Left Ventricular Assist Device End-to-End Connection to the Left Subclavian Artery: An Alternative Technique.

We describe a modified implantation technique for the HeartWare ventricular assist device. We access the apex through a left minithoracotomy. The outflow graft is tunneled through a small incision in the fourth intercostal space and then subcutaneously to the subclavian region. After division of the left axillary artery, an end-to-end anastomosis is performed to the proximal part, and the distal vessel is connected end-to-side through a fenestration in the outflow graft. We believe that this technique, particularly suitable for redo scenarios or severely calcified aorta, achieves a more direct blood flow into the aorta and reduces cerebrovascular events while avoiding excessive flow to the arm.

In vitro comparison of different mechanical prostheses suitable for replacement of the systemic atrioventricular valve in children.

OBJECTIVE: The aim of the present study was to compare the hydrodynamics of 4 different mechanical prostheses fitting the atrioventricular annulus in children. METHODS: We tested different inverted aortic prostheses with a prosthesis-annulus relationship in the mitral chamber of the Sheffield pulse duplicator (Department of Medical Physics and Clinical Engineering, Royal Hallamshire Hospital, Sheffield, UK), analyzed by comparing the prosthetic housing diameter and the predicted annulus diameter based on body surface area (0.8 and 1 m(2) corresponding to an annulus diameter of 18.8-20.2 mm). The On-X 19 (On-X Life Technologies, Inc, Austin, Tex), SJM Regent 19 (St Jude Medical Inc, St Paul, Minn), Sorin Overline 18 (Sorin Biomedica, Saluggia, Italy), and Medtronic Advantage Supra 19 (Medtronic Inc, Minneapolis, Minn) valves with a housing diameter of 19 to 20 mm were hydrodynamically compared. The tests were carried out at increasing pulse rate of 72, 80, 100, and 120 beats/min for a stroke volume of 20 and 30 mL. Therefore, cardiac output ranged from 1.44 to 3.6 L/min. RESULTS: Regardless of the pulse rate and stroke volume, the Medtronic Advantage Supra valve showed the highest mean diastolic pressure difference at each cardiac output (P < .05). The mean gradients were significantly lower for the Sorin Overline valve regardless of the cardiac output, stroke volume, and pulse rate (P < .05). The effective orifice areas observed followed exactly the same behavior: the lowest for the Medtronic Advantage Supra valve and the highest for the Sorin Overline valve. The Sorin Overline valve showed the highest closure volumes (P < .05), and the On-X prosthesis showed the highest leakage volumes (P < .05). The Sorin Overline valve had the highest total regurgitant volume (P < .05), and the Medtronic Advantage Supra valve had the lowest total regurgitant volume (P < .05). The On-X valve showed the highest total energy loss regardless of the pulse rate at 20 mL of stroke volume, which was comparable to the SJM Regent and Sorin Overline valves at increased stroke volume. The Medtronic Advantage Supra valve showed the lowest total energy loss regardless of cardiac outputs (P < .05). CONCLUSIONS: This hydrodynamic evaluation model allowed us to compare the efficiency of currently available valve prostheses suitable for atrioventricular replacement in children. Among these prostheses, the Sorin Overline valve showed the best diastolic performance. On the other hand, for total energy loss, the Medtronic Advantage Supra valve demonstrated excellent performance.

Aortic valve hydrodynamics: considerations on the absence of sinuses of Valsalva.

BACKGROUND AND AIM OF THE STUDY: The study aim was to compare the hydrodynamics of the Carpentier-Edwards Magna 21 (CEM) and St. Jude Medical Biocor-Epic-Supra 21 (SJME) valves at increasing stroke volume and pulse rate in two different aortic conduits, namely straight and with sinuses of Valsalva present. METHODS: Both valve types were tested in the aortic chamber of the Sheffield pulse duplicator, at rates of 70, 80 and 90 beats/min, and stroke volumes of 50 and 60 ml. The systolic and diastolic performances were each recorded. The leaflet coaptation time, ventricle isovolumetric time and maximum instantaneous flow rate were also recorded. RESULTS: Regardless of the aortic conduit, CEM valves showed a significantly lower gradient than SJME valves (p < 0.05), and a significantly larger effective orifice area (EOA) (p < 0.05); the latter parameter was unaffected for both valves, at an increasing pulse rate (p > 0.05). The maximum transvalvular flow velocity was significantly higher in the straight conduit for both valves (p < 0.05). With regards to diastole, the SJME valve showed the lowest regurgitant volume (p < 0.05). The leaflet coaptation time was significantly shorter for the SJME valve than for the CEM valve (p < 0.05), but when tested in a straight conduit it was shortened significantly for both valves (p < 0.05). CONCLUSION: An absence of the sinuses of Valsalva may modify the diastolic and systolic behaviors of the tissue valve leaflets by reducing the time required for leaflet coaptation, and increasing the valve closing volume and maximum transvalvular flow velocity. It is speculated that these hydrodynamic changes may increase the working stress on the valve tissue, leading to possible premature structural valve deterioration.