A clampless and sutureless aorto-prosthetic end-to-side anastomotic device: an experimental study.

OBJECTIVES: A feasibility study. METHODS: Eight pigs (all females; mean weight: 29 kg) underwent a conventional transperitoneal aortic approach with implantation of an aorto-prosthetic end-to-side anastomosis using a Clampless device and deployment of a 5-mm polytetrafluoroethylene (PTFE) graft. After proximal ligature, a conventional end-to-end anastomosis was then performed between the graft and the left iliac artery. RESULTS: The first pig died during the procedure due to graft misplacement. The seven other procedures were successful with a mean operative and anastomosis time of 101 min (range: 81-115 min) and 3.35 min (range: 2.25-4.25 min), respectively; mean blood loss was 152 ml (range: 30-235 ml). Another pig with a patent graft died at day 4 as a result of a severe unrelated pneumonopathy. The angiogram performed during the procedure and before sacrifice, at 2 (n=2), 4 (n=2) and 6 weeks (n=2), showed no graft stenosis or thrombosis. Microscopic examination revealed a tissue covering the intraluminal stent, which evolved over time, with no visible endothelial proliferation or inflammation. CONCLUSION: An aorto-prosthetic anastomosis can be performed safely and efficiently with our new clampless and sutureless device. The next step will be a laparoscopic Clampless implantation.

Evaluation of a new vascular suture system for aortic laparoscopic surgery: an experimental study on pigs and cadavers.

OBJECTIVES: The aim of this study was to assess the feasibility and efficacy of a new laparoscopic vascular suturing device. METHODS: Animal study: six pigs underwent surgery using a retroperitoneal laparoscopic approach. Aorto-prosthetic side-to-end and end-to-end anastomoses were performed laparoscopically on each pig using SuDyn. Clamping and anastomosis times, as well as the properties of the anastomoses, were recorded. Study on cadavers: four aorto-prosthetic end-to-end anastomoses were performed using the direct transperitoneal laparoscopic approach to assess the feasibility of the SuDyn device on atherosclerotic aortas. RESULTS: Animal study: No pigs died and 12 patent and impermeable anastomoses were obtained. Mean anastomosis time was 38(+/-8)min for end-to-side anastomoses and 37(+/-5)min for end-to-end anastomoses. Study on cadavers: Totally laparoscopic anastomoses were performed in 4 human cadavers with a mean anastomosis time of 37(+/-3)min. CONCLUSIONS: SuDyn makes laparoscopic aorto-prosthetic anastomoses easier to perform, produces good results and does not require a learning curve.

In-vitro measurements of the regurgitation of mechanical mitral heart valve prostheses in case of atrial fibrillation.

BACKGROUND AND AIM OF THE STUDY: The characterization of heart valve prostheses requires regurgitation tests to be conducted in pulsatile flow. Although tests are generally conducted in accordance with hemodynamic conditions of a healthy young man, heart valve implantation is often associated with other pathology, such as atrial fibrillation. To run more realistic trials, four mechanical heart valve prostheses were tested with, and then without, atrial contraction. METHODS: The dual activation simulator (DAS) allow simulation of physiologically normal and pathological flows through the mitral valve. The DAS comprises silicon-based cavities, is activated by pumps, and was equipped successively with monoleaflet (Björk-Shiley, Medtronic Hall) and bileaflet (St. Jude Medical, CarboMedics) valves. Each valve (mitral, size 27 mm) was tested under two conditions (with and without atrial contraction) at a mean flow rate of 3 l/min of glycerol/water solution (analog blood viscosity). RESULTS: Leakage volumes were of the same magnitude as the precision of the instruments. Respectively, closing volumes increased from normal conditions to atrial fibrillation from 3.2 to 5.1 ml for Björk-Shiley, from 4.6 to 6.3 ml for Medtronic Hall, from 5 to 6.6 ml for St. Jude Medical, and from 5.2 to 5.4 ml for CarboMedics. The standard deviation was below the precision of measurements (+/- 0.5 ml). CONCLUSION: Without atrial contraction, the valves seemed to be closed by backward flow only, thus confirming earlier reports. This study showed that different heart valves behave differently in pathological situations with regard to their design; this must be considered when selecting a valve for implantation.

A new dual activation simulator of the left heart that reproduces physiological and pathological conditions.

Heart valve replacements are often associated with cardiac pathologies, but valvular prostheses are still tested in vitro under the same physiological conditions as for a healthy young man. Therefore a new mock circulatory system of the left heart, the dual activation simulator (DAS), has been built. The DAS allows atrial and ventricular dynamics to be controlled with pumps that activate anatomically shaped silicon models of the cavities. The mitral flow is a two-peak waveform. The E/A ratio can be changed, and the A-wave can be suppressed to simulate, for instance, atrial fibrillation. The cardiac rhythm and the mean flow-rate can be changed at will. The ability of the DAS to reproduce physiological flow is assessed by computation of the aortic input impedance and by harmonic analysis of left ventricular and atrial pressures. It allows the behaviour of valve prostheses to be studied in various conditions of concern to clinicians and can be a useful tool for engineers to improve valve prostheses or validate diagnostic tools such as 3D colour Doppler. The DAS and its capacities are described.