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PubMed1979

Cardiac valve replacement. Problems solved and unsolved.

In this review the present state of cardiac valve replacement is summarized on the basis of the literature and personal experience in approximately 1500 cases, using various prosthetic models. Durability, hemodynamic performance at rest and during exercise, and thromboembolic risk are considered in particular and our choice of the various valve models is discussed on these grounds. The long-term durability has been significantly improved and has possibly been solved in the more advanced mechanical valves, while this question is still open in the present biological prostheses. Hemodynamic performance is considered less than optimal in all conventional mechanical prostheses and in the xenografts. Pressure gradients are abnormal in all mechanical as well as in stented biological prostheses, the latter being less likely to solve the problem of a narrow aortic root. The significantly lower incidence of thromboembolism and total valve thrombosis and the absence of anticoagulation accidents in patients with bioprostheses has tipped the balance for the present in favor of the latter, particularly in mitral valve replacement and certainly in all those patients in whom anticoagulation in impossible, unlikely, or undesirable.

Aortic Valve↗

PubMed1979

RIGHT AND LEFT VENTRICULAR HEMODYNAMIC INDICES AS PREDICTORS OF THE NEED FOR AND OUTCOME OF POST-CARDIOTOMY MECHANICAL INTRAAORTIC BALLOON PUMP SUPPORT.

Preoperative cardiac catheterization data of 21 patients requiring intraaortic balloon pumping (IABP) for weaning from cardiopulmonary bypass were analyzed and compared with similar data in 28 patients who underwent nearly similar operative procedures, but did not require IABP for weaning. Cardiac index (CI) and systemic vascular resistance (SVR) were found to have predictive value for the need of IABP for weaning from cardiopulmonary bypass and differentiated survival from non-survival. Left ventricular end diastolic pressure (LVEDP) was not found to be predictive. Ejection fraction (EF) was significantly lower in those who required IABP than those who did not; EF did not predict the outcome. Pulmonary capillary wedge pressure ([unk]), pulmonary artery pressure ([unk]) and pulmonary vascular resistance (PVR) were predictive of the need for IABP, but not the outcome. Left ventricular minute work index (LVMWI) was significantly lower in those requiring IABP, right ventricular minute work index (RVMWI) was predictive of survival with IABP. Together, LVMWI and RVMWI were predictive of the need for and outcome of IABP following cardiopulmonary bypass. Twenty-seven of 28 control RVMWI's were normal. No patient requiring IABP had depressed RVMWI's preoperatively. Elevated preoperative RVMWI's were associated with 80% survival with postcardiotomy IABP; normal RVMWI's were associated with a 56% survival with post-cardiotomy IABP. Elevated preoperative RVMWI's reflected moderate to maximal right ventricular compensatory capacity in response to depressed left ventricular function. Normal preoperative RVMWI's in the presence of depressed LVMWI's were indicative of decreased right ventricular compensatory capacity in post-cardiotomy IABP-support settings. Right ventricular function is as important as left ventricular function as a prognosticator for the need and outcome of IABP support of the failing post-cardiotomy circulation.

Journal Article↗