117,320 research outputs found
How to achieve an aortic root remodelling by performing an aortic root reimplantation
No full textThe aortic root remodelling procedure, introduced by Yacoub in the early 1980s, is the valve-sparing aortic root replacement procedure that better reproduces the anatomical and functional properties of the native aortic root. Long-term durability of the repair, in terms of freedom from recurrent aortic regurgitation, has been questioned and can probably be improved by appropriate patient selection. Reproducibility of the operation, however, depends on subjective evaluations and surgical skill. We report a simplification of the technique designed to possibly increase the reproducibility of the aortic root remodelling operation while retaining its functional advantages
Reduction of allogeneic red blood cell usage during cardiac surgery by an integrated intra- and postoperative blood salvage strategy: results of a randomized comparison.
No full textBACKGROUND: The amount of allogeneic blood transfusion may relate to worse outcome in cardiac surgery. The reinfusion of red blood cells (RBCs) lost by patients, including those of chest drains, is a promising strategy to minimize allogeneic transfusions. STUDY DESIGN AND METHODS: To verify this hypotheis, 1047 cardiac surgery patients were randomly assigned to either traditional intraoperative blood salvage followed by chest drain insertion or intra- and postoperative strategy with the Haemonetics cardioPAT system. Allogeneic RBC transfusion rate (primary endpoint) and postoperative complications (secondary endpoint) were recorded at the time of discharge from the hospital and at first month follow-up visit, respectively. RESULTS: The cardioPAT arm received 1.20 units of allogeneic RBCs per patient, whereas the control group required 2.11 units per patient, and this difference proved to be highly significant (p=0.02). We observed a comparable 45-day mortality rate but a lower rate of deep vein thrombosis (p=0.04) and atrial fibrillation (p=0.04) in the cardioPAT arm. DISCUSSION: A significant reduction in patient exposure to allogeneic RBCs was observed in the cardioPAT system arm. Complications were slightly less frequent in the cardioPAT group. The use of the cardioPAT is a safe and effective strategy to reduce allogeneic RBC transfusions in cardiac surgery
Differences in aortic cusp coaptation between the reimplantation and the remodeling techniques of aortic valve-sparing surgery: An in vitro porcine model study
No full textWe sought to evaluate the effects of the reimplantation type versus the remodeling type of aortic valve-sparing technique on the geometry of the same aortic root
The combined role of sinuses of Valsalva and flow pulsatility improves energy loss of the aortic valve
No full textNormal aortic valve opening and closing movement is a complex mechanism mainly regulated by the blood flow characteristics and the cyclic modifications of the aortic root. Our previous in vitro observations demonstrated that the presence of the Valsalva sinuses, independently from root compliance, is important in reducing systolic pressure drop across the aortic valve. This in vitro study was designed to ascertain if this effect is dependent on the flow characteristics.Stentless 21, 23 and 25 mm aortic prostheses were sutured inside Dacron graft with and without sinuses. Hydrodynamic performance of the root models was investigated in steady-state (continuous) and unsteady-state (pulsatile) flow regimes. Aortic transvalvular pressure drop and effective orifice area (EOA) were evaluated.The continuous flow analysis revealed that no marked differences in pressure drop characterized the two root configurations at flow regimes lower than 15 l/min, independently of valve size. Conversely, at higher flow regimes (up to 30 l/min) a relatively low pressure drop continued to characterize grafts with sinuses, whereas marked increments in pressure drop were measured in straight grafts, especially in the smaller size (77.05 +/- 4.58 vs 23.80 +/- 2.44 mmHg; 18.40 +/- 1.31 vs 7.66 +/- 0.37 mmHg and 29.54 +/- 0.17 vs 7.12 +/- 0.07 mmHg, for 21, 23 and 25 mm valve, respectively). Under pulsatile conditions, the presence of sinuses clearly confirmed lower pressure drops also more evident in the smaller valve sizes (53.89 +/- 1.06 vs 11.6 +/- 0.24 mmHg at 7 l/min for 21 mm valve). EOA values were always lower in the absence of sinuses. In continuous flow regimes, at 30 l/min EOA of 25 mm valve size was 3.67 +/- 0.02 cm(2) in the Valsalva model versus 1.79 +/- 0.01 cm(2) for the Straight model. In pulsatile tests, at 7 l/min a 25-valve size demonstrated an EOA of 5.47 +/- 0.60 in the Valsalva model versus 2.50 +/- 0.02 cm(2) in the Straight model.These findings (i) confirm the hypothesis that the sinuses of Valsalva play a key role in optimizing the aortic haemodynamics during systole, minimizing energy losses; (ii) suggest that the sinuses of Valsalva are needed because of the complex nature of blood flow during ejection
Twenty years of experience with combined carotid endoarterectomy and coronary artery bypass grafting
No full textEvaluation of prosthetic-valved devices by means of numerical simulations
No full textThe in vivo evaluation of prosthetic device performance is often difficult, if not impossible. In particular, in order to deal with potential problems such as thrombosis, haemolysis, etc., which could arise when a patient undergoes heart valve replacement, a thorough understanding of the blood flow dynamics inside the devices interacting with natural or composite tissues is required. Numerical simulation, combining both computational fluid and structure dynamics, could provide detailed information on such complex problems. In this work, a numerical investigation of the mechanics of two composite aortic prostheses during a cardiac cycle is presented. The numerical tool presented is able to reproduce accurately the flow and structure dynamics of the prostheses. The analysis shows that the vortical structures forming inside the two different grafts do not influence the kinematics of a bileaflet valve or the main coronary flow, whereas major differences are present for the stress status near the suture line of the coronaries to the prostheses. The results are in agreement with in vitro and in vivo observations found in literature
Twenty years of experience with combined carotid endoarterectomy and coronary artery bypass grafting.
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