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N °57 Perfusion 2018, Vol. 33(1S) 18–23
New, optimized, dual-lumen cannula for veno-venous ECMO
LK von Segesser, D Berdajs, S Abdel-Sayed, E Ferrari, M Halbe, M Wilhelm and F Maisano

Objective: The present study was designed to assess in vivo a new, optimized, virtually wall-less, dual-lumen, bi-caval cannula for veno-venous ECMO in comparison to a commercially available cannula.

Methods: Veno-venous extracorporeal membrane oxygenation (ECMO) was carried out in a bovine study (n=5,bodyweight 75±5kg). Following systemic heparinization, ECMO was established in a trans-jugular fashion through a calibrated 23F orifice, using a new, optimized, virtually wall-less, dual-lumen, bi-caval 24F cannula (Smartcanula LLC, Lausanne, Switzerland) versus a commercially available 23F bi-caval, dual-lumen control cannula (Avalon Elite®, Maquet, Rastatt, Germany) in a veno-venous ECMO setup. Veno-venous ECMO was initiated at 500 revolutions per minute (RPM) and increased by incremental steps of 500 RPM up to 2500 RPM. Catheter outlet pressure, catheter inlet pressure, oxygen saturation and pump flow were recorded at each stage.

Results: Mean flow accounted for 0.37±0.04 L/min for wall-less versus 0.29± 0.07 L/min for control at 500 RPM, 0.97±0.12 versus 0.67±0.06 at 1000 RPM, 1.60±0.14 versus 1.16±0.08 at 1500 RPM, 2.31±0.13 versus 1.52±0.13 for 2000 RPM and 3.02±0.5 versus 2.11±0.18 (p<0.004). The mean venous suction required was 19±8 mmHg for wall-less versus 20±3 mmHg for control at 500 RPM, 7±3 versus 9±4 for 1000 RPM, -11±10 versus -12±8 at 1500 RPM, -39±15 versus -49±10 for 2000 RPM and -60±28 versus -94±7 for 2500 RPM. The mean venous injection pressure accounted for 29±7 mmHg for wall-less versus 27±5 mmHg for control at 500 RPM, 50±6 versus 61±7 at 1000 RPM, 89±10 versus 99±17 for 1500 RPM, 142±14 versus 161±9 at 2000 RPM and 211±41 versus 252 ±3 for 2500 RPM.

Conclusion: Compared to the commercially available control cannula, the new, optimized, virtually wall-less, dual-lumen, bi-caval 24F cannula allows for significantly higher blood flows, requires less suction and results in lower injection pressures in vivo.

N °56 Innovations (Phila). 2018 Mar/Apr;13(2):104-107. doi: 10.1097/IMI.0000000000000478
Clinical Experience in Minimally Invasive Cardiac Surgery With Virtually Wall-Less Venous Cannulas
E Ferrari E, LK von Segesser, D Berdajs, L Müller, M Halbe, F Maisano

OBJECTIVE: Inadequate peripheral venous drainage during minimally invasive cardiac surgery (MICS) is a challenge and cannot always be solved with increased vacuum or increased centrifugal pump speed. The present study was designed to assess the benefit of virtually wall-less transfemoral venous cannulas during MICS.

METHODS: Transfemoral venous cannulation with virtually wall-less cannulas (3/8″ 24F 530-630-mm ST) was performed in 10 consecutive patients (59 ± 10 years, 8 males, 2 females) undergoing MICS for mitral (6), aortic (3), and other (4) procedures (combinations possible). Before transfemoral insertion of wall-less cannulas, a guidewire was positioned in the superior vena cava under echocardiographic control. The wall-less cannula was then fed over the wire and connected to a minimal extracorporeal system. Vacuum assist was used to reach a target flow of 2.4 l/min per m with augmented venous drainage at less than -80 mm Hg.

RESULTS: Wall-less venous cannulas measuring either 630 mm (n = 8) in length or 530 mm (n = 2) were successfully implanted in all patients. For a body size of 173 ± 11 cm and a body weight of 78 ± 26 kg, the calculated body surface area was 1.94 ± 0.32 m. As a result, the estimated target flow was 4.66 ± 0.78 l/min, whereas the achieved flow accounted for 4.98 ± 0.69 l/min (107% of target) at a vacuum level of 21.3 ± 16.4 mm Hg. Excellent exposure and "dry" intracardiac surgical field resulted.

CONCLUSIONS: The performance of virtually wall-less venous cannulas designed for augmented peripheral venous drainage was tested in MICS and provided excellent flows at minimal vacuum levels, confirming an increased performance over traditional thin wall cannulas. Superior results can be expected for routine use.

N °55 ASAIO J. 2016 Jul-Aug;62(4):427-31. doi: 10.1097/MAT.0000000000000377
New Dual Lumen Self-Expanding Catheter Design Requiring Less Suction.
S Abdel-Sayed , LK von Segesser

Contribution of venovenous extracorporeal membrane oxygenation (v-v ECMO) to gas transfer is flow dependent. Catheter design is a key factor for optimal pressure/flow rate relationship. This study was designed for the assessment of a new self-expanding dual lumen catheter design versus the current standard. Outlet pressure/flow rate and inlet pressure/flow rate for a new Smart catheter with self-expanding dual lumen design constricted to 27 F with 5 mm long constrictor corresponding to the percutaneous path versus Avalon 27 F catheter (control) were compared on a flow bench with a Biomedicus centrifugal pump. Flow, pump inlet pressure and outlet pressure were determined at 500, 1,000, 1,500, 2,000, and 2,500 revolutions per minute (RPM).
At 500 RPM and with a 5 mm long constrictor (1,000; 1,500; 2,000; and 2,500 RPM), catheter outlet pressure values were -0.13 ± 0.07 mm Hg (-2.55 ± 0.06; -7.38 ± 0.14; -15.03 ± 0.44; -26.46 ± 0.39) for self-expanding versus -2.93 ± 0.23* (-10.60 ± 0.14; -22.74 ± 0.34; -38.43 ± 0.41; -58.25 ± 0.40)*: p < 0.0001* for control. The flow values were 0.61 ± 0.01 L/min (1.64 ± 0.03, 2.78 ± 0.02; 4.07 ± 0.04; 5.37 ± 0.02) for self-expanding versus 1.13 ± 0.06*; (2.19 ± 0.04; 3.30 ± 0.03; 4.30 ± 0.03; 5.30 ± 0.03)*: p < 0.0001* for control.
The corresponding catheter inlet flow rates of the self-expanding catheter were slightly more than that of the control. For the given setup, our evaluation demonstrated that the new dual lumen self-expanding catheter requires lower catheter outlet pressures for higher flows as compared to the current standard.

N °54 Innovations (Phila) 2016; 11: 278-81
New, virtually wall-less cannulas for augmented venous drainage in minimally invasive cardiac surgery
LK von Segesser, D Berdajs, S Abdel-Sayed, P Tozzi, E Ferrari, F Maisano

Inadequate venous drainage during minimally invasive cardiac surgery becomes most evident when the blood trapped in the pulmonary circulation floods the surgical field. The present study was designed to assess the in vivo performance of new, thinner, virtually wall-less, venous cannulas designed for augmented venous drainage in comparison to traditional thin-wall cannulas.
Remote cannulation was realized in 5 bovine experiments (74.0 ± 2.4 kg) with percutaneous venous access over the wire, serial dilation up to 18 F and insertion of either traditional 19 F thin wall, wire-wound cannulas, or through the same access channel, new, thinner, virtually wall-less, braided cannulas designed for augmented venous drainage. A standard minimal extracorporeal circuit set with a centrifugal pump and a hollow fiber membrane oxygenator, but no in-line reservoir was used. One hundred fifty pairs of pump-flow and required pump inlet pressure values were recorded with calibrated pressure transducers and a flowmeter calibrated by a volumetric tank and timer at increasing pump speed from 1500 RPM to 3500 RPM (500-RPM increments).
Pump flow accounted for 1.73 ± 0.85 l/min for wall-less versus 1.17 ± 0.45 l/min for thin wall at 1500 RPM, 3.91 ± 0.86 versus 3.23 ± 0.66 at 2500 RPM, 5.82 ± 1.05 versus 4.96 ± 0.81 at 3500 RPM. Pump inlet pressure accounted for 9.6 ± 9.7 mm Hg versus 4.2 ± 18.8 mm Hg for 1500 RPM, -42.4 ± 26.7 versus -123 ± 51.1 at 2500 RPM, and -126.7 ± 55.3 versus -313 ± 116.7 for 3500 RPM.
At the well-accepted pump inlet pressure of -80 mm Hg, the new, thinner, virtually wall-less, braided cannulas provide unmatched venous drainage in vivo. Early clinical analyses have confirmed these findings.

N °53 Swiss Medical Weekly 2016; 146: w 14304
Prevention and therapy of leg ischemia in extracorporeal life support and extracorporeal membrane oxygenation with peripheral cannulation
LK von Segesser, S Marinakis, D Berdajs, E Ferrari, M Wilhelm, F Maisano

Extracorporeal Membrane Oxygenation (ECMO) and Extracorporeal Life Support (ECLS) have been around for a long time, but it is only in recent years with the advent of acute respiratory distress syndrome consecutively to influence A (H1N1) infection that these life saving technologies have seen a broader application. Although the results of ECLS and ECMO are perceived as encouraging in general, there are still disturbing complications related to peripheral cannulation in general and more specifically to cannulation in the groin. The present review was designed to assess the magnitude of this latter problem, i.e. leg ischemia related to ECLS and ECMO in the literature and to identify strategies for possible therapies and more importantly, prevention.
The search strategy selected identified 7 original articles totalizing 407 patients who underwent veno-arterial ECMO and on large review. For the original reports, the number of cases with veno-arterial support ranges from 21-143, with, as far as available, a range of ischemic complications between 11% and 52%, a reported range of surgical intervention between 9% and 22%, and a leg amputation rate ranging from 2% to 10%. It appears that the number of reports dealing with lower extremity ischemia during ECMO increases in parallel with the number of reports about ECMO. Strategies for early detection of peripheral ischemia, interventions for efficient reperfusion, and measures for prevention including new concepts with smaller and eventually bidirectional arterial cannulas are discussed.

N °52 European Journal of Cardiothoracic Surgery 2015, 10 (Suppl1): A123
How to get a bloodless surgical field in mini-invasive cardiac surgery
LK von Segesser, D Berdajs, S Abdel-Sayed, P Tozzi, E Ferrari

Virtually wall-less cannulas designed for augmented venous drainage allow for unmatched venous drainage in vivo despite a small 18F access orifice and relatively low negative pressure.

N °51 European Journal of Cardio-Thoracic Surgery 2015; 48: 499-501
Use of self-expanding venous cannula in tricuspid reoperation
Pinon M, Pradas G, Molina D, Legarra JJ

Tricuspid surgery on cardiopulmonary bypass with single transfemoral smart cannulation of the right atrium, without superior and inferior vena caval snaring, is feasible and safe by using a suitable self-expanding venous cannula. This technique adds to the advantages of peripheral cannulation by lowering the risk of injuries associated with reoperation. The limitation of the right atrial surface area that needs to be exposed reduces the morbidity related to the surgical procedure. Peripheral cannulation also enhances the surgical field through having no cannula present in the field. Moreover, excellent venous drainage without augmentation was achieved here, consistent with previous reports on the use of these cannulae. Also, complications of vacuum-assisted venous return, such as the collapse of the caval axis during cardiopulmonary bypass, are avoided, thus providing an optimal flow and an improved end-organ perfusion.

N °50 Swiss Medical Weekly 2014 DOI: 10.4414/smw.2014.14022
Late removal of retrievable caval filters
von Segesser L, Ferrari E, Tozzi P, Abdel-Sayed S, Berdajs D

Retrievable caval filters inserted for thrombo-embolic prophylaxis in the acute setting often become permanent despite the initial decision of temporary use (designed implant duration < 30 days). However, such “forgotten“ retrievable devices can still be removed with a great chance of success up to three months after implantation. Conventional percutaneous removal techniques (catheters, hooks, lassos, etc.) may be sufficient up to sixteen months after implantation whereas more sophisticated catheter techniques have been shown to be successful up to 83 months or more than seven years of implant duration. Tilting, migrating, or misplaced devices should be removed early on, and replaced if indicated with a device which is both, efficient and retrievable.

N °49 Interactive CardioVascular and Thoracic Surgery 2014 DOI: 10.1093/iscvts/ivu 318
Venous cannula performance assessment in a realistic caval tree model
Li L. Abdel-Sayed S, Berdajs D, Ferrari E, von Segesser L

The objective of this study was to assess cannula performance for virtually wall-less cannulas designed for augmented venous drainage versus standard percutaneous thin-walled venous cannulas in a setting of venous collapse in case of negative pressure. For the thin wall and the wall-less cannulas, 36 pairs of flow and pressure measurements were realized for three different centrifugal pump RPM values. The mean Q-values at 1500, 2000 and 2500 RPM were: 3.98 ± 0.01, 6.27 ± 0.02 and 9.81 ± 0.02 l/min for the wall-less cannula (P <0.0001), versus 2.74 ± 0.02, 3.06 ± 0.05, 6.78 ± 0.02 l/min for the thin-wall cannula (P <0.0001). The corresponding inlet pressure values were: −8.88 ± 0.01, −23.69 ± 0.81 and −70.22 ± 0.18 mmHg for the wall-less cannula (P <0.0001), versus −36.69 ± 1.88, −80.85 ± 1.71 and −101.83 ± 0.45 mmHg for the thin-wall cannula (P <0.0001). The thin-wall cannula showed mean Q-values 37% less and mean P values 26% more when compared with the wall-less cannula (P <0.0001).

N °48 Artificial organs 2014 DOI: 10.1111/aor.12369
Effect of inflow cannula tip design on potential parameters of blood compatibility and thrombosis
Wong KC, Büsen M, Benzinger C, Gäng R, Bezema M et al.

Cannula tip design strongly affects the function of a cannula and its potential for blood trauma. Inflow cannulas with conventional tip geometries (Blunt, blunt with four side holes, beveled with three side ports and cage) were compared to a custom designed crown tip in vitro using particle flow velocimetry. Among the five tip geometries, the highest shear volume was observed for the blunt tip, whereas the crown tip had the lowest recirculation volume.

N °47 Perfusion 2014 DOI: 10.1177/0267659114560042
How to prevent caval cannula orifice obstruction during extracorporeal circulation
Abdel-Sayed S, Favre J, von Segesser LK

Venous cannula orifice obstruction is an underestimated problem during augmented cardiopulmonary bypass (CPB), which can potentially be reduced with redesigned, virtually wall-less cannula designs versus traditional percutaneous control venous cannulas. A bench model, allowing for simulation of the vena cava with various affluent orifices, venous collapse and a worst case scenario with regard to cannula position, was developed. Flow (Q) was measured sequentially for right atrial + hepatic + renal + iliac drainage scenarios, using a centrifugal pump and an experimental bench set-up (afterload 60 mmHg). This experimental evaluation demonstrates that the redesigned, virtually wall-less cannulas, allowing for direct venous drainage at practically all intra-venous orifices, outperform the commercially available control cannula, with superior flow at reduced suction levels for all scenarios tested.

N °46 European Journal of Cardio-Thoracic Surgery 2014; 43: 306-312
Caval collapse during cardiopulmonary bypass: a reproducible bench model
Li L. Abdel-Sayed S, Berdajs D, Tozzi P, von Segesser L, Ferrari E

Based on data for venous anatomy and physiology from the literature, a caval tree system is designed (polyethylene, thickness 0.061 mm), which receives venous inflow from nine afferent veins representing all major affluent. With water as medium and a preload of 4.4 mmHg, the system has an outflow of 4500 ml/min (Scenario A). After the insertion of a percutaneous venous cannula (23-Fr), the venous model is continuously served by the afferent branches in a venous test bench and venous drainage is augmented with a centrifugal pump (Scenario B).This caval model provides a realistic picture for the limitations of flow due to spontaneously reversible atrial chatter versus irreversible venous collapse for a given negative pressure during CPB. Temporary interruption of negative pressure in the venous line can allow for recovery of venous drainage. This know-how can be used not only for testing different cannula designs, but also for further optimizing perfusion strategies.

N °45 Innovations 2014; 9: 297-301
Performance increase in venous drainage for mini-invasive heart surgery. Superiority of self-expanding cannulas
Belkoniene M., Abdel-Sayed S, Favre J., von Segesser LK

Experimental evaluation of a new 14F self-expanding cannula designed for use in combination with augmentation by a centrifugal pump (or vacuum) was to standard 25F percutaneous thin wall cannulas. Superior flow (3.6 l/min to 11.8 l/min) at a fraction of negative pressure (-5.4 to -80.6 mmHg) was demonstrated for the self-expanding design at all pump speeds of 1500, 2000, 2500, and 300 RPM.

N °44 European Journal of Cardio-Thoracic Surgery 43 (2013) 665–672
The contraindications of today are the indications of tomorrow
Ludwig K. von Segesser

One of the remaining problems during ECMO is the considerable haemodilution, which can become a major issue. However, stripped down, integrated pump-oxygenator designs have been developed with minimized priming volumes below 400 ml for the entire circuit, which allow for stealth perfusion provided adequate cannulation is realized. Pump flows up to 6 l/min can be realized without significant modification of the haematocrit. A different issue is the scavenging of a major part of the circulating blood volume in the pulmonary circulation in patients with weak or fibrillating heart, a situation where the aortic valve does not open, and nothing can be ejected from the left ventricle. Remote pulmonary artery drainage by flexible wall-less venous cannulas (Smartcanula LLC, Lausanne, Switzerland) introduced from the groin through the tricuspid and the pulmonary valves is promising for this scenario.

N ° 43 ASAIO Journal 2013;59:46–51
Prevention of Caval Collapse During Venous Drainage for CPB
Saad Abdel-Sayed, Julien Favre, Steven Taub,* and Ludwig-Karl von Segesser

A new plastic self-expanding Smartcanula is designed for central insertion and prevention of caval collapse. The objective is to assess the influence of the new design on atrial chatter. Caval collapse over the entire caval axis, right atrial, hepatic, renal vein, and iliac vein is realized in drainage tubes with holes at 5 cm distance intervals. Smartcanulas with various lengths (26 cm [= right atrial], 34 cm [= hepatic], 43 cm [= renal], and 53 cm [= iliac]) versus two-stage cannulas are compared. The Smartcanula outperforms significantly the two-stage control cannula. In addition, direct central smart cannula insertion without guide-wire is effective.

N ° 42 Anesthesiology. 2013; 119: 365-378
Interactions of Cardiopulmonary Bypass and Erythrocyte Transfusion in the Pathogenesis of Pulmonary Dysfunction in Swine
Patel NN, Lin H, Jones C, Walkden G, Ray P, Sleeman PA, Angelini GD, Murphy GJ.

Thirty-six pigs were infused with allogeneic 14- or 42-day-old erythrocytes or they underwent cardiopulmonary bypass after smart cannulation with or without transfusion of 42-day erythrocyte. Controls received saline. All pigs were recovered and assessed for pulmonary dysfunction, inflammation, and endothelial activation at 24 h

N ° 41 Interact Cardiovasc Thorac Surg. 2012 Oct;15(4):574-7. Epub 2012 Jul 9.
How to improve flow during cardiopulmonary bypass in an acardia experimental model.
Marinakis S, Niclauss L, Rolf T, von Segesser LK.

In extreme scenarios,such as hyperacute rejection of heart transplant, an urgent heart explantation might be necessary. Veno-arterial cardiopulmonary bypass after cardiectomy may allow to bridge such a situation. Baseline pump flow was 4.16 ± 0.75 l/min dropping to 2.9 ± 0.63 l/min (p< 0.001) 10 min after induction of ventricular fibrillation. After cardiectomy with the pulmonary artery clamped, the pump flow increased non-significantly to 3.20 ± 0.78 l/min. After declamping, the flow significantly increased to (3.61 ± 0.73 l/min, P(DB )= 0.009, P(DC )= 0.017), supporting the notion that full cardiopulmonary bypass in acardia is feasibleprovided adequate drainage of pulmonary circulation is maintained.

N ° 40 Amsect Abstracts 2012
ECMO Circulatory Support After Cardiectomy; How To Improve Flow?
Marinakis S, von Segesser L

Purpose: Veno-arterial bypass is commonly used for cardiorespiratory support in acute cardiac failure. In extreme scenarios, such as hyperacute rejection of heart transplant, an urgent heart explantation might be necessary. The aim of this experimental study was to determine the feasibility and to improve the hemodynamics of a venoarterial cardiopulmonary bypass after cardiectomy.
Methods: A venoarterial cardiopulmonary bypass was established in 4 bovine experiments (56 +/- 5 kg) by the transjugular insertion to the caval axis of a self expanded cannula, with return through a carotid artery. After baseline measurements (A), ventricular fibrillation was induced (B), the great arteries were clamped, the heart was excised and right and left atria remnants, containing the pulmonary veins, were sutured together leaving an atrial septal defect (ASD) over the cannula in the caval axis. Measures were taken with the pulmonary artery clamped (C) and declamped (D).
Results: Initial pump flow (A) was 3.7+/-0.8 L/min dropping to 2.7+/-0.2 L/min on induction of ventricular fibrillation (B). After cardiectomy, with the pulmonary artery clamped (C) it continued to decrease to 2.4+/-0.2 L/min, due to pulmonary congestion from the left to right shunt of bronchial circulation. Finally, after declampation (D), flow significantly raised, almost to baseline (3.45+/-0.5 L/min), supporting that pulmonary artery drainage is necessary to maintain cardiac output in acardia.
Conclusions: Full circulatory support in acardia is feasible, making cardiectomy a possibility in situations where heart must urgently be explanted. However, in order to optimise pump flow, pulmonary artery drainage must be assured to avoid pulmonary congestion and loss of volume.

N ° 39 Int J Artif Organs 2012; 35: 132-138
Characterizing the impact of minor cannula design modification
Abdel-Sayed S, Favre J, von Segesser LK

The hydrodynamic behaviour of self-expanding venous cannulas with either 8 mm versus 9 mm connecting tube measuring 100 mm in length was assessed on a test bench with a computerized recording system. Flow accounted for 7.22±0.10 l/min for the 8 mm connecting tube versus 7.81±0.04 for the 9 mm version. A 17% reduced resistance was also observed for the 9 mm connecting tube. Obviously, even minor cannula design modifications have a significant impact on drainage.

N ° 38 ACTA-SCTS, Manchester, April 18-20, 2012: Abstract book 230
A novel and safe approach to complex aortic surgery
Lu J, Shajar M, Campbell J, Hammond S, Nalk S

The Smart venous cannula is inserted percutaneously without skin incision and re-expanded in situ. Superior flow, much smaller access aperture, and less trauma result. This avoids the need for vacuum assisted drainage and minimizes trauma to blood components. It particularly improves the venous drainage of the lower body and hence reduces the ischemic risk to the gut and the kidneys. Closure of femoral vein in open cannulation can be difficult and this technique avoids the problem.

N ° 37 Int J Artif Organs 2012; 35 (2): 132-138
Characterizing the impact of minor cannula design modification
Saad Abdel-Sayed1, Julien Favre, Ludwig K. von Segesser

Objective: Bench evaluation of the hydrodynamic behavior of venous cannulas is a valuable technique for the analysis of their performance during cardiopulmonary bypass (CPB). The aim of this study was to investigate the effect of the internal diameter of the extracorporeal connecting tube of venous cannulas on flow rate (Q), pressure drop (?P), and cannula resistance (?P/Q2) values, using a computer assisted test bench.
Methods: An in vitro circuit was set up with silicone tubing between the test cannula encased in a movable reservoir, and a static reservoir. The ?P, defined as the difference between the drainage pressure and the preload pressure, was measured using high-fidelity Millar pressure transducers. Q was measured using an ultrasonic flowmeter. Data display and data recording were controlled using virtual instruments in a stepwise fashion.
Results: The 27 F Smartcanula® with a 9 mm connecting tube diameter showed 17% less resistance compared to that with an 8 mm connecting tube diameter. Q values were 7.22±0.1 and 7.81±0.04 L/min for cannulas with 8 mm and 9 mm connecting tube diameters, respectively. The ?P/Q2 ratio values were 72% lower for the cannula with a 9 mm connecting tube diameter compared to that with an 8 mm connecting tube diameter. Q values for the control cannula were 3.94±0.23 and 6.58±0.04 L/min with 8 mm and 9 mm connecting tube diameters, respectively. The 27 F Smartcanula ® showed 13% more flow rate compared to the 28 F Medtronic cannula using the unpaired Student t-test (p<0.0001).
Conclusions: Our results demonstrated that Q was increased but ?P and ?P/Q2 values were significantly decreased when the connecting tube diameter was increased for venous cannulas. The connecting tube diameter significantly affected the resistance to liquid flow through the cannula. Smartcanulas ® outperform control cannulas.

N ° 36 Am J Physiol Renal Physiol 301: F605–F614, 2011
Reversal of anemia with allogenic RBC transfusion prevents post-cardiopulmonary bypass acute kidney injury in swine
Nishith N. Patel, Hua Lin, Tibor Toth, Gavin I. Welsh, Ceri Jones, Paramita Ray, Simon C. Satchell, Philippa Sleeman, Gianni D. Angelini, and Gavin J. Murphy

Anemia during cardiopulmonary bypass (CPB) is strongly associated with acute kidney injury in clinical studies; however, reversal of anemia with red blood cell (RBC) transfusions is associated with further renal injury. To understand this paradox, we evaluated the effects of reversal of anemia during CPB with allogenic RBC transfusion in a novel large-animal model of post-cardiac surgery acute kidney injury with significant homology to that observed in cardiac surgery patients. Adult pigs undergoing general anesthesia were allocated to a Sham procedure, CPB alone, Sham_RBC transfusion, or CPB_RBC transfusion, with recovery and reassessment at 24 h. CPB was associated with dilutional anemia and caused acute kidney injury in swine characterized by renal endothelial dysfunction, loss of nitric oxide (NO) bioavailability, vasoconstriction, medullary hypoxia, cortical ATP depletion, glomerular sequestration of activated platelets and inflammatory cells, and proximal tubule epithelial cell stress. RBC transfusion in the absence of CPB also resulted in renal injury. This was characterized by endothelial injury, microvascular endothelial dysfunction, platelet activation, and equivalent cortical tubular epithelial phenotypic changes to those observed in CPB pigs, but occurred in the absence of severe intrarenal vasoconstriction, ATP depletion, or reductions in creatinine clearance. In contrast, reversal of anemia during CPB with RBC transfusion prevented the reductions in creatinine clearance, loss of NO bioavailability, platelet activation, inflammation, and epithelial cell injury attributable to CPB although it did not prevent the development of significant intrarenal vasoconstriction and endothelial dysfunction. In conclusion, contrary to the findings of observational studies in cardiac surgery, RBC transfusion during CPB protects pigs against acute kidney injury. Our study underlines the need for translational research into indications for transfusion and prevention strategies for acute kidney injury.

N ° 35 Care Med 2011 Vol. 39, No. 4: 793-802
Prevention of post-cardiopulmonary bypass acute kidney injury by endothelin A receptor blockade
Nishith N. Patel, MBBS, MRCS; Tibor Toth, MD, MRCPath; Ceri Jones, BSc; Hua Lin, PhD; Paramita Ray, MB ChB, FRCA; Sarah J. George, PhD; Gavin Welsh, PhD; Simon C. Satchell, PhD, MRCP; Philippa Sleeman, BSc; Gianni D. Angelini, MD, FRCS; Gavin J. Murphy, MD, FRCS

Objective: The aim of this study was to determine whether administration of a specific endothelin A receptor antagonist, sitaxsentan sodium, would prevent the development of postcardiopulmonary bypass acute kidney injury in swine.
Design: Experimental study.
Setting: Cardiovascular Research Institute.
Interventions: Adult pigs (n _ 8 per group) were randomized to undergo a sham procedure, cardiopulmonary bypass, or cardiopulmonary bypass plus administration of endothelin A receptor antagonist (RA), with recovery and reassessment at 24 hrs.
Measurements and Main Results: Cardiopulmonary bypass resulted in a significant reduction in creatinine clearance relative to sham pigs (mean difference for cardiopulmonary
bypass vs. sham, -50.3 mL/min [95% confidence interval -89.2 to -11.4 mL/min], p= .008). This was reversed by the administration of endothelin A RA during cardiopulmonary bypass (mean difference for cardiopulmonary bypass+ endothelin A RA vs. cardiopulmonary bypass, +43.3 mL/min [95% confidence interval +3.3 to +83.4 mL/min], p= .030). Cardiopulmonary bypass also resulted in a significant rise in the specific urinary biomarker of acute kidney injury interleukin-18 compared to sham procedures (mean difference +209 pg/mL [95% confidence interval +119 to +299 pg/mL], p< .001) that was reversed by endothelin A receptor antagonist administration. Post-cardiopulmonary bypass kidney injury was associated with vascular endothelial injury and dysfunction,reduced nitric oxide bioavailability, inflammation, and a significant increase in the expression of the paracrine vasoconstrictors adenosine and endothelin-1. In post-cardiopulmonary bypass kidneys at 24 hrs there was persistent hypoxia at the level of the outer medulla, cortical adenosine triphosphate depletion, and evidence of proximal tubule epithelial cell stress manifest as phenotypic change. There was no evidence of acute tubular necrosis. Administration of endothelin A RA to cardiopulmonary bypass pigs reversed endothelial dysfunction, regional hypoxia, inflammation, and tubular changes.
Conclusion: In this model, post-cardiopulmonary bypass acute kidney injury is associated with endothelial dysfunction, regional tissue hypoxia, and proximal tubular epithelial cell stress but not acute tubular necrosis. Antagonism of the endothelin-1 A receptor reversed these changes and may represent a therapeutic target for the prevention of post-cardiac surgery acute kidney injury

N ° 34 Ann Thorac Surg 2011; 92: 2168 –76
Phosphodiesterase-5 Inhibition Prevents Postcardiopulmonary Bypass Acute Kidney Injury in Swine
Nishith N. Patel, MRCS, Hua Lin, MS, Tibor Toth, MD, MRCPath, Ceri Jones, BS, Paramita Ray, FRCA, Gavin I. Welsh, PhD, Simon C. Satchell, PhD, MRCP, Philippa Sleeman, BS, Gianni D. Angelini, MD, FRCS, and Gavin J. Murphy, MD, FRCS

Background. Acute kidney injury after cardiac surgery is common, has no effective treatments, and is associated with adverse outcomes. The aim of this study was to determine whether administration of the phosphodiesterase-5 inhibitor sildenafil citrate (SDF) would prevent the development of post–cardiopulmonary bypass (CPB acute kidney injury in swine.
Methods. Adult pigs (n= 8 per group) were randomized to undergo sham procedure, CPB, or CPB plus administration of SDF, with recovery and reassessment at 24 hours.
Results. Cardiopulmonary bypass resulted in a significant reduction in creatinine clearance relative to sham pigs (mean difference CPB versus sham, -47.9 mL/min; 95% confidence interval [CI]: -93.7 to -2.2; p = 0.039). This was prevented by the administration of SDF during CPB (mean difference CPB+SDF versus CPB, +55.6 mL/min; 95% CI: +6.5 to +104.7; p = 0.024). Cardiopulmonary bypass also resulted in a significant rise in the urinary biomarker interleukin-18 compared with sham procedures (mean difference 209.3 pg/mL; 95% CI: 120.6 to 298.1; p< 0.001) that was prevented by SDF administration. Post-CPB kidney injury was associated with vascular endothelial injury and dysfunction, reduced nitric oxide bioavailability, medullary hypoxia, cortical adenosine triphosphate depletion, inflammation, and evidence of proximal tubule epithelial cell stress manifest as phenotypic change. Administration of SDF to CPB pigs preserved nitric oxide bioavailability and prevented endothelial dysfunction, regional hypoxia, inflammation, and tubular changes.
Conclusions. In this model, phosphodiesterase-5 inhibition using SDF prevented post-CPB acute kidney injury by the preservation of nitric oxide bioavailability, and warrants evaluation as a renoprotective agent in clinical trials.

N ° 33 Medimond 2012 NX23 C0002 407-415
A new plastic self-expanding cannula for central insertion
Abdel-Sayed S, Favre J, von Segesser LK

A new plastic self expanding cannula is designed to fit with all sizes of adult right atrium and vena cava(<34F). AN in vitro circuit was set-up with silicone tubing between the test cannula encased in amovable reservoir, and a static reservoir. At 90 cm height differential, the flow values were 8.88±0.05 l/min as compared to 8.05±0.05 l/min for a typical 32/42 F two stage cannula. Despite the 38% smaller access orifice, the new self-expanding plastic cannula outperforms the typical two stage cannulas.

N ° 32 Kardiotechnik 2011; 4: 111-113
Erfahrungen mit der Smartcanula® zur venösen Drainage im Langzeiteinsatz
Straub A, Schnu W, Quinz H, Oertel F, Beyer M

The Smartcanula® was used for venous cannulation in 26 ECMO/ECLS runs for up to 17 days. In addition the Smartcanula® was used without oxygenator in two cases for right ventricular assist (RVAD) with the Centrimag® pump. The experience with the Smartcanula® was very positive in all patients. Pump flows of more than 5 l/min were reached without problem and maintained over prolonged periods. No air-leak or thromboses were observed, and there were no technical complications. Insertion and removal of the Smartcanula® was easy.

N ° 31 Perfusion 2011 ; 26 : 271-275
No prototype of femoral arterial Smartcanula® with anterograde and retrograde flow
Berdajs D, Ferrari E, MIchalis A, Burki M, Pieterse CW, Horisberger J, von Segesser LK

A modified, bidirectional arterial Smartcanula® (18F, 130mm long) was compared to aretrograde rectilinear percutaneous cannula (19F) with an antegrade 8F shunt in bovine experiments (67.6±5.1 kg). The modified, bidirectional, arterial Smartcanula® provided up to 50% superior antegrade flow as compared to the traditional method relying on a retrograde cannula with an antegrade shunt.

N ° 30 Interactive CardioVascular and Thoracic Surgery 13 (2011) 591-596
The new advanced membrane gas exchanger
Denis A. Berdajs*, Eleonora de Stefano, Dominique Delay, Enrico Ferrari, Judith Horisberger, Quntin Ditmar, Ludwig K. von Segesser

Current membrane oxygenators are constructed for patients with a body surface under 2.2 m2. If the body surface exceeds 2.5 m2, com¬mercially available devices may not allow adequate oxygenation during cardiopulmonary bypass. To address this, a hollow-fiber oxygenator with an enlarged contact surface of 1.81 m2 was tested. In an experimental set-up, six calves of mean weight 85.4±3 kg were connected to cardiopulmonary bypass. They were randomly assigned to a standard oxygenator (n=3; ADMIRAL, Euroset, Medola, Italy) with a surface of 1.35 m2 or to an enlarged surface oxygenator (n=3; AMG, Euroset). Blood samples were taken before bypass, after 10 min on bypass, and after 1, 2, 5 and 6 h of perfusion. Analysis of variance was used for repeated measurements. The mean flow rate was 6.5 l/min for 6 h. The total oxygen transfer at 6 h was significantly higher in the high-surface group (P<0.05). Blood trauma, evaluated by plasma hemoglobin and lactate dehydrogenase levels, did not detect any significant hemolysis. Thrombocytes and white blood cell count profiles showed no significant dif¬ferences between the two groups at 6 h of perfusion (P=0.06 and 0.80, respectively). At the end of testing, no clot deposition was found in the oxygenator, and there was no evidence of peripheral emboli. The results suggest that the new oxygenator allows very good gas transfer and may be used for patients with a large body surface area.

N ° 29 Ter verkrijging van de graad van doctor aan de Universiteit Maastricht, op gezag van de Rector Magnificus, Prof. mr. G.P.M.F. Mols, volgens het besluit van het College van Decanen, in het openbaar te verdedigen op woensdag 23 juni 2010 om 14:00 uur
To drain or not to drain: Quantification of drainable intravascular venous volume during extracorporeal life support
Antoine B. Simons

Previous work has shown, that patient filling is a fundamental ingredient for successful operation of extracorporeal life support (ELS). This thesis focuses on the interaction of the support system and the patient’s circulation with respect to patient filling, and in addition highlights hardware components used in extracorporeal circulation. Several references to the Smartcanula® are made throughout this work.
Chapter 2 presents a possible method to detect and reverse venous collapse resulting of low filling during extracorporeal life support, and uses in vitro and animal experimental data providing evidence for the rationale.
Chapter 3 illustrates the impact of tip design of different venous cannulae for central cannulation on drainage performance during obstruction of the inlet. A mock circulation was used to induce vessel collapse resulting of excessive drainage with insufficient filling.
Chapter 4 describes a clinical investigation of a measurement method to assess volume available for drainage during the application of minimized extracorporeal bypass systems. Luxation of the heart during coronary artery bypass surgery was used to change volume that can be potentially drained by the minimized extracorporeal circuit, and acted as a model for decreased circulatory filling. Data from transesophageal echocardiography were used to verify the impact of luxation on drainable volume.
Chapter 5 shows proof of principle for a reserve-driven pump control for extracorporeal life support, and presents animal experimental data in which the controller is tested during an acute condition of low filling.
Chapter 6 presents a case report in which a new approach for the quantitative assessment of cardiac load-responsiveness is introduced, and discusses its potential for assisting future weaning from extracorporeal life support.
Chapter 7 discusses a new pulsatile centrifugal blood pump described in literature and its potential for application in minimized bypass circuits as used in extracorporeal life support (letter in response to an original publication).
Chapter 8 offers a general discussion of the individual chapters and major findings, and provides a basis for future research on extracorporeal life support.

N ° 28 CardioVascular and Thoracic Surgery 10 (2010) 873–876
Self-expanding mini-cannula for remote perfusion with pediatric scenarios
Denis A. Berdajs, Enrico Bernandi, Marco Burki, Michel Hurni, Piergiorgo Tozzi, Judit Horisberger, Ludwig K. von Segesser

The aim of this report is to address the benefits of the minimal invasive venous drainage in a pediatric cardio surgical scenario. Juvenilebovine experiments (67.4"11 kg) were performed. The right atrium was cannulated in a trans-jugular way by using the self-expandable (Smart Stat, 12y20F, 430 mm) venous cannula (Smartcannula_ LLC, Lausanne, Switzerland) vs. a 14F 250 mm (Polystan Lighthouse) standard pediatric venous cannula. Establishing the cardiopulmonary bypass (CPB), the blood flows were assessed for 20 mmHg, 30 mmHg and 40 mmHg of driving pressure. Venous drainage (flow in lymin) at 20 mmHg, 30 mmHg, and 40 mmHg drainage load was 0.26"0.1, 0.35"0.2 and 0.28"0.08 for the 14F standard vs. 1.31"0.22, 1.35"0.24 and 1.9"0.2 for the Smart Stat 12y20F cannula. The 43 cm self-expanding 12y20F Smartcannula_ outperforms the 14F standard cannula. The results described herein allow us to conclude that usage of the selfexpanding Smartcannula_ also in the pediatric patients improves the flow and the drainage capacity, avoiding the insufficient and excessive drainage. We believe that similar results may be expected in the clinical settings.

N ° 27 Journal of Cardio-thoracic Surgery 36 (2009) 665—669
Superior flow for bridge to life with self-expanding venous cannulas
Ludwig K. von Segesser, Martens Kalejs, Enrico Ferrari, Sandra Bommeli, Olaf Maunz, Judith Horisberger, Piergiorgio Tozzi

Background: Recently, a compact cardiopulmonary support (CPS) system designed for quick set-up for example, during emergency cannulation, has been introduced. Traditional rectilinear percutaneous cannulas are standard for remote vascular access with the original design. The present study was designed to assess the potential of performance increase by the introduction of next-generation, self-expanding venous cannulas, which can take advantage of the luminal width of the venous vasculature despite a relatively small access orifice.
Methods: Veno-arterial bypass was established in three bovine experiments (69 ± 10 kg). The LifebridgeW (Lifebridge GmbH, Munich, Germany) system was connected to the right atrium in a trans-jugular fashion with various venous cannulas; and the oxygenated blood was returned through the carotid artery with a 17 F percutaneous cannula. Two different venous cannulas were studied, and the correlation between the centrifugal pump speed (1500—3900 RPM), flow and the required negative pressure on the venous side was established: (A) Biomedicus 19 F (Medtronic, Tolochenaz, Switzerland); (B) Smart canula 18 F/36 F (Smartcanula LLC, Lausanne, Switzerland).
Results: At 1500 RPM, the blood flow was 0.44 ± 0.26 l min-1 for the 19 F rectilinear cannula versus 0.73 ± 0.34 l min-1 for the 18/36 F self-expanding cannula. At 2500 RPM the blood flow was 1.63 ± 0.62 l min-1 for the 19 F rectilinear cannula versus 2.13 ± 0.34 l min-1 for the 18/36 F self-expanding cannula. At 3500 RPM, the blood flow was 2.78 ± 0.47 l min-1 for the 19 F rectilinear cannula versus 3.64 ± 0.39 l min-1 for the 18/36 F self-expanding cannula ( p< 0.01 for 18/36 F vs 19 F). At 1500 RPM, the venous line pressure was 18 _ 8 mmHg for the 19 F rectilinear cannula versus 19 _ 5 mmHg for the 18/36 F selfexpanding cannula. At 2500 RPM the venous line pressure accounted for -22 ± 32 mmHg for the 19 F rectilinear cannula versus 2 ± 5 mmHg for the 18/36 F self-expanding cannula. At 3500 RPM, the venous line pressure was -112 ± 42 mmHg for the rectilinear cannula versus 28 ± 7 mmHg for the 18/36 F self-expanding cannula ( p< 0.01 for 18 F/36 F vs 19 F).
Conclusions: The negative pressure required to achieve adequate venous drainage with the self-expanding venous cannula accounts for approximately 31% of the pressure necessary with the 19 F rectilinear cannula. In addition, a pump flow of more than 4 l min_1 can be achieved with the self-expanding design and a well-accepted negative inlet pressure for minimal blood trauma of less than 50 mmHg.

N ° 26 Interact CardioVasc Thorac Surg 2009; 8 Suppl 1: S87 Full paper link
Total cardiac unloading without augmentation for beating heart LVAD implantation
E. Ferrari, P. Tozzi, S. Bommeli, D. Delay, L. K. von Segesser

Trans-femoral venous smart cannulation of the caval axis provides total unloading of the heart, thus allowing for beating heart trans-apical cannulation for LVAD implantation: calculated target flow was 4.54±0.26 l/min and achieved flow accounted for 5.43±0.55 l/min (119.6% of target).

N ° 25 Interact CardioVasc Thorac Surg 2009; 8 Suppl 1: S54 Full paper link
Self expanding arterial cannula for cardiopulmonary bypass: hemodynamic performance in an animal model
S. Bommeli, E. Ferrari, E.Bernadini, L. K. von Segesser

This experimental study shows two very interesting findings:
A) trans-jugular venous smart cannulation allows to generate flows up top 6 l/min in bovine with a mean bodyweight of 61.7±1.5 kg without augmentation
B) up to 6 l/min can be returned to the animal through a 15F orifice using an arterial smart canula with acceptable pressure gradients.

N ° 24 Perfusionist 2009; 33: 9-10 Full paper link
Venous drainage is key for CPB
L. K. von Segesser

The importance of venous drainage is often underestimated during cardiopulmonary bypass. At typical flow rates for adult patients of 4 I/min, even a venous reservoir level of 2.5 litres provides sufficient volume to maintain flow for just about 30 seconds (= 2 litres) if venous drainage is interrupted for some reason (eg venous line collapse, air lock etc). However, for a reservoir level of 500 ml at the time of venous drainage shut-down, the remaining time for action is close to zero. Hence, the quality of the blood inflow into the pump-oxygenator is of prime importance, and it has been well demonstrated the self-expanding venous smart canula ® allows for significant improvement of the latter.

N ° 23 European Journal for Cardiothoracic Surgery. 2008;34:635-40 Abstract link
Routine use of self-expanding venous cannulas for cardiopulmonary bypass: benefits and pitfalls in 100 consecutive cases
L. K. von Segesser, E. Ferrari, D. Delay, O. Maunz, J. Horisberger, P. Tozzi

A prospective study was realized in 100 unselected consecutive patients undergoing open-heart surgery with either remote or central smart venous cannulation. The study focuses on the 76 consecutive adult patients (mean age 59.2+/-17.3 years; 60 males, 16 females) undergoing surgical procedures with total cardiopulmonary bypass for either valve procedures (42/76 patients=55.3%), ascending aorta and arch repair (20/76 patients=26.3%), coronary artery revascularization (13/76 patients=17.1%) or other procedures (11/76 patients=14.5%) with 14/76 patients (18.4%) undergoing redo surgery and 6/76 patients (7.9%) undergoing small access surgery. Full or more than target flow was achieved in 97% of the patients studied undergoing CPB with self-expanding venous cannulas and gravity drainage. Remote venous cannulation with self-expanding cannulas provides similar flows as central cannulation. Augmentation of venous return is no longer necessary.

N ° 22 Interactive CardioVascular and Thoracic Surgery. 2008; 7:1096-100 Full paper link
Temporary caval stenting improves venous drainage during cardiopulmonary bypass
L. K. von Segesser G. Siniscalch, K. Kang, O. Maunz, J. Horisberger, E. Ferrari, D. Delay, P. Tozzi

Temporary caval stenting was realized in bovine experiments (65+/-6 kg) by the means of self-expanding (18F for insertion, 36F in situ) venous cannulas (Smartcanula LLC, Lausanne, Switzerland) with various lengths: 43 cm, 53 cm, 63 cm versus a standard 28F wire armed cannula in trans-jugular fashion and maximal blood flows were assessed. The 43 cm self-expanding 36F smartcanula outperforms the 28F standard wire armed cannula at low drainage pressures and without augmentation. Temporary caval stenting with long self-expanding venous cannulas provides even better drainage (+51%).

N ° 21 The Thoracic and Cardiovascular Surgeon 2008; 56: 337-41 Abstract link
A simple way to decompress the left ventricle during veno-arterial bypass
L. K. von Segesser, W. Dembitsky, E. Ferrari, D. Delay, J. Horisberger, P. Tozzi

Venoarterial bypass was established in the experimental setting and cardiogenic shock was simulated with ventricular fibrillation induced by an external stimulator. Left ventricular decompression was achieved by switching to transfemoral drainage of the pulmonary artery with a long self-expanding cannula. Remote drainage of the pulmonary artery during venoarterial bypass allowed for effective decompression of the left ventricle and provided superior hemodynamics.

N ° 20 Perfusion. 2007 Nov; 22: 411-6 Abstract link
New bench test for venous cannula performance assessment
S. Abdel-Sayed, J. Favre, J. Horisberger, S. Taub, D. Hayoz, L. K. von Segesser

Cannula design is of prime importance for venous drainage during cardiopulmonary bypass (CPB). To evaluate cannulas intended for CPB, an in vitro circuit was set up with silicone tubing between the test cannula encased in a movable preload reservoir and another static reservoir. Out of five cannulas tested, the Smartcanula outperforms the other commercially available cannulas. The mean (DeltaP/Q) values were 3.3 +/- 0.08, 4.07 +/- 0.08, 5.58 +/- 0.10, 5.74 +/- 0.15, and 6.45 +/- 0.15 for Smart, Medtronic, Edwards, Sarns, and Gambro cannulas, respectively (two-way ANOVA, p < 0.0001). In conclusion, the present assay allows discrimination between different forms of cannula with high or low lumen resistance.

N ° 19 Innovations 2006; 4: 213-4 Abstract link
Selfexpanding Cannulas For Combined Use With Valved Stent Based Interventions. Superior Cardiopulmonary Flows In Small Vessels - A Smarter Choice
C. Huber, G. Murphy, I. Mallabiabarrena, I. Seigneul, M. Augstburger, G. Mucciolo, D. Jegger, J. Horisberger, S. Taub, L. K. von Segesser

The smart canula ®was able to sustain significantly (p< 0.0001) higher CPB flows of 3.9±0.7L/min with a mean arterial pressure of 74.7±20.7mmHg compared to 2.8±1.5L/min of flow for the dlp cannula with a MAP of 71.3±19.9mmHg. Native macroscopic inspection and Evans blue vital staining as well as histological analysis of various jugular vein segments confirmed absence of endothelial damage.

N ° 18 Multimedia Manual for Cardiothoracic Surgery 2006; doi:10.1510/mmcts.2005.001610 Full paper link
Peripheral cannulation for cardiopulmonary bypass
L. K. von Segesser

Although most open heart procedures are nowadays realized with central cannulation, there is renewed interest in remote cannulation through the femoral, iliac, axillary, subclavian and jugular vessels. Remote cannulation is not only of interest in hemodynamically unstable patients who can be put on cardiopulmonary bypass in local anesthesia, and stabilized prior to intubation, but also for complex procedures like replacement of the thoracoabdominal aorta, acute type A aortic dissections, complex redo open heart surgery, extracorporeal membrane oxygenation, and more recently, small access open heart surgery, robotic surgery, and others. Venous canulation with self-expanding smart canulase allows for full flow with gravity drainage and does not require adjuncts for augmentation.

N ° 17 European Journal of Cardio-thoracic Surgery 2006; 29: 525-529 Abstract link
A novel technique using echocardiography to evaluate venous cannula performance perioperatively in CPB cardiac surgery
D. Jegger, P-G. Chassot, M-A. Bernath, J. Horisberger, P. Gersbach, P. Tozzi, D. Delay, L. K. von Segesser

An epicardial echocardiography probe was placed over the venous smart canula ® or a control two-stage cannula during open heart surgery with CPB and central cannulation (right atrium to aorta) and a Doppler image was obtained. The main findings of this study include superior blood flow for the venous smart canula ® despite a smaller access aperture and lower pressure drop as compared to classic two stage venous cannulae. There was no difference between groups with regard to blood trauma.

N ° 16 The Heart Surgery Forum 2005; 8: 241-5 Abstract link
The smart canula ®: A new tool for remote access perfusion in limited access cardiac surgery
L. K. von Segesser, D. Jegger, G. Mucciolo, P. Tozzi, A. Mucciolo, D. Delay, I. Mallabiabarrena, J. Horisberger

Smart canula ® performance was assessed in a small series of patients (76 ± 17 kg) undergoing ascending aortic redo procedures. The calculated target pump flow (2.4 L/min/m2)in these patients was 4.42 ± 61 L/ min. Mean pump flow achieved during cardiopulmonary bypass was 4.84 ± 87 L/min or 110% of the target. Reduced atrial chatter, kink resistance in situ, and improved blood drainage despite smaller access orifice size, are the most striking advantages of this new device.

N ° 15 Swiss Medical Weekly 2005; 136: 235-7 Full paper link
Hepato-atrial anastomosis, the "other Senning operation" for treatment of Budd-Chiari syndrome
D. Delay, C. Lardi, A. Jaussi, L. K. von Segesser

The smart canula ® was used in femoral position for repair of an Intra-hepatic vena cava occlusion. Trans-atrial resection and hepato-atrial anastomosis was realized in open fashion (no snears). Full pump flow and excellent visibility intra-hepatic and intracaval visibility were achieved throughout the procedure.

N ° 14 Artificial Organs 2004 ; 28 : 649-54
Vascular access for cardiopulmonary bypass procedures
D. Jegger, J. Horisberger, Y Boone, I. Seigneuil, M. Jachertz, Holzmann, L. K. von Segesser

Not only catheter diameter , but also catheter drainage hole surface and the catheter diameter to the patients veins diameter ratio correlate with flow. The smart canula ® maximizes hole surface area and minimizes wall thickness in order to improve flow rate and vascular access to the patient.

N ° 13 Syllabus of Postgraduate Course on Perfusion by the European Association for Cardio-thoracic Surgery, Leipzig 2004
Systemic venous return: Can we help Newton?
A. F. Corno

The limitations of current venous cannulae and related technologies for augmentation of venous return are summarized. The smart canula ® allowing for adequate venous return with gravity drainage alone outperforms traditional approaches.

N ° 12 European Journal for Cardio-thoracic Surgery 2004; 26: 219-20
Right atrial surgery with un-snared inferior vena cava
A. F. Corno, J. Horisberger, D. Jegger, L. K. von Segesser

Femoral cannulation with the smart canula ® allows for open right atrial surgery without snaring the inferior vena cava. Despite full pump flow, the supra-hepatic veins can be inspected in detail and cavo-atrial anastomoses or extra-cardiac tunnels for Fontan completion can be realized with unmatched comfort.

N ° 11 Business Briefings: Surgery 2003
A smart solution for cannulation bottleneck
L. K. von Segesser

Flow-wise, the highest benefits with the smart canula ® can be achieved by peripheral cannulation. However, use of the smart canula ® is also beneficial for central cannulation, where the access aperture can be reduced from 50F or more to less than 30F without compromising pump flow.

N ° 10 Swiss Perfusion 2003; 12: 22-25 Full paper link
In vivo analysis of the smart canula ® for assisted venous drainage applications
D. Jegger, J. Horisberger, Y. Boone, M. Jachertz, I. Seigneul, M. Augstburger, L. K. von Segesser

For assisted venous drainage applications, the smart canula ®outperforms standard and percutaneous type venous cannulas. The smart canula ® in combination with gravity drainage achieves the same flow as standard and percutaneous cannulas in combination with a centrifugal pump in the venous line. Hence, with the smart canula ®, centrifugal pump augmentation is not necessay.

N ° 09 Perfusion 2003 ; 18 : 219-224
Miniaturization in cardiopulmonary bypass
L. K. von Segesser, P. Tozzi, I. Mallbiabarrena, J. Horisberger, A. Corno

Miniaturization is key to further reduction of the priming volumes in cardiopulmonary bypass. This report provides an up-date of already commercially availableand up-coming low-prime perfusion devices like the smart canula ® with its revolutionary cannulation concept.

N ° 08 Perfusion 2003; 18: 61-65Abstract link
A prototype paediatric venous cannula with shape change in situ
D. Jegger, A. F. Corno, A Mucciolo, G. Mucciolo, Y. Boone, J. Horisberger, I. Seigneul, M. Jachertz, L. K. von Segesser

Bench tests simulating a collapsible vein of a pediatric cannula based on the smart canula ®principle shows superior flow if compared to classic single stage cannulas typically used for paediatric cardiopulmonary bypass.

N° 07 The Annals of Thoracic Surgery 2002; 74: S1330-3 Abstract link
A new expandable venous cannula for minimal acces heart surgery
X Mueller, H tevaearai, D. Jegger, J. Horisberger, G. Mucciolo, L. K. von Segesser

In vivo evaluation of the smart canula ® in comparison to typical percutaneous venous canulas shows 34 % more flow for a 27 F access aperture, 42 % more flow for a 25 F access aperture and 53 % more flow for a 21% access aperture.

N ° 06 The International Journal of Artificial Organs 2002; 25: 672
A new expandable pediatric venous cannula which changes shape in situ
D. Jegger, X. Mueller, G. Mucciolo, Y. Boone, J. Horisberger, L. K. von Segesser

In vitro evaluation of a new pediatric cannula based on the smart canula ® principle shows superior flow if compared to standard pediatric cannulas.

N ° 05 ASAJO Journal 2002; 48: 132
The smart canula: a new concept for improved venous drainage with no impact on blood cell integrity
X. Mueller, H. Tevaearai, D. Jegger, J. Horisberger, G. Mucciolo, L. K. von Segesser

The smart canula ® with its innovative design for improved drainage has no impact on formed blood elements when compared with standard single stage cannulas.

N° 04 The International Journal of Artificial Organs 2002; 25: 136-40
A new expandable cannula to increase venous return during peripheral access cardiopulmonary bypass surgery
D. Jegger, X. Mueller, G. Mucciolo, Y. Boone, I. Seigneul, J. Horisberger, L. K. von Segesser

Benchtests simulating drainage of a collapsible vein showed superior performance for the smart canula ® as compared to standard cannulas.

N ° 03 Interactive Cardiovascular and Thoracic Surgery 2002; 1: 23-7 Full paper link
Optimized venous return with a self expanding cannula: From computational fluid dynamics to clinical application
X Mueller, I Mallabiabarena, G Mucciolo, LK von Segesser

Computational fluid dynamics, animal experiments, and first clinical use confirm superior performance of smart canula ®: includes discussion.

N° 02 Cardiovascular Engineering 2002; 7: 23-4
Optimisation of venous return with a self-expandable canula
X Mueller, D Jegger, J Horisberger, G Mucciolo, A Mucciolo, LK von Segesser

Preliminary experimental evaluation in vivo showed better performance for smart canula ®.

N° 01 The International Journal of Artificial Organs 2001; 24: 532
A new expandable canula to increase venous return during peripheral access in cpb surgery
D Jegger, X Mueller, G Mucciolo, Y Boone, I Seigneul, J Horisberger, LK von Segesser

Benchtests showed higher flows for the smart canula ® as compared to standard cannulas.

Patents: US 6626859, WO 015273, AU770989, JP5059305, EP1248571, US8679053, EP1651121, HK1091109, US7967776, CN02149340, US8992455, US8679053
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