Long-Term Outcomes After Valve Replacement for Low-Gradient Aortic Stenosis

Abstract

Background-The long-term outcomes of patients with low-gradient aortic stenosis (LGAS) after aortic valve replacement (AVR) are poorly defined. The purpose of this study was to define the long-term outcomes of LGAS patients after AVR and to evaluate the potential impact of prosthesis-patient mismatch (PPM) in these patients. Methods and Results-A cohort of 664 patients undergoing AVR for aortic stenosis after 1990 were followed-up prospectively with annual clinical assessment and echocardiography (total follow-up 3447 patient-years; mean follow-up 5.2Ϯ3.3 years).LGAS was defined as an aortic valve area Ͻ1.2 cm 2 , a mean transvalvular pressure gradient Ͻ40 mm Hg, and a left ventricular (LV) ejection fraction Ͻ50%, and was present in 79 patients. Rates and correlates of survival, freedom from congestive heart failure (CHF), and LV mass regression after AVR were determined using multivariate regression methods. Ten-year survival and freedom from CHF after AVR were 72.7Ϯ7.5% and 68.2Ϯ9.5%, respectively, for patients with LGAS, compared with 89.6Ϯ1.8% and 84.1Ϯ4.2% for patients without LGAS (hazard ratio [HR] for death and postoperative CHF, 3.1Ϯ1.1 and 2.7Ϯ0.9, respectively; PϽ0.01). In LGAS patients, PPM, defined as an indexed effective orifice area Յ0.85 cm 2 /m 2 , was independently associated with increased rates of CHF (HR, 3.6Ϯ2.2; Pϭ0.039), impaired LV mass regression (Pϭ0.037), and a trend toward increased late mortality (HR, 3.0Ϯ1.9; Pϭ0.084). Conclusions-Patients withLGAS have worse long-term outcomes after AVR compared with patients without LGAS.PPM adversely affects the long-term outcomes of LGAS patients and should be avoided in this population.

Prosthesis-patient Mismatch after Mitral Valve Replacement Stratified by Referred and Measured Effective Valve Area

“…3) Though many have reported a link between PPM after aortic valve replacement (AVR) and late left ventricular function, cardiac events or survival, some do not agree that the link exists. [4][5][6][7][8][9][10][11][12][13][14] On the other hand, the focus of attention on PPM is its occurring after AVR instead of mitral valve replacement (MVR). Within the past 10 years, there has been greater interest in PPM after MVR.…”

Ejection Fraction/Velocity Ratio Identifies Prosthesis-Patient Mismatches in Patients With Aortic Bioprosthetic Valves and Left Ventricular Dysfunction

“…11,12 Previous studies identified a PPM as an independent predictor of a higher incidence of congestive heart failure and impaired left ventricular mass regression after AV replacement in patients with impaired left ventricular function; conversely, a PPM of 0.85 cm 2 /m 2 or less does not result in an appreciable detrimental effect on overall longterm survival, freedom from heart failure, and left ventricular mass regression in patients with normal preoperative left ventricular function. 15,16 Evaluation of bioprostethic function and the indexed EOA measurement is mandatory in patients receiving a biological prosthesis in the aortic position. In the presence of a poor LVEF 19 observed that a 4V 2 of greater than 50 mm Hg was highly specific (94%) but poorly sensitive (48%) for identifying patients with severe aortic stenosis.…”

New concepts in valvular hemodynamics: Implications for diagnosis and treatment of aortic stenosis

“…Indeed, it is well known that a failing ventricle is much more sensitive to a moderate increase in afterload than a normal ventricle (64,65). Although there are no direct data regarding this issue in the context of low-flow AS, an analogy can, however, be made with recent studies showing that moderate patient-prosthesis mismatch, which is a postoperative equivalent to moderate native AS in terms of LV afterload, has no significant impact on mortality in patients with preserved LV systolic function, but a major impact on mortality in patients with poor ventricular function (66)(67)(68). Hence, it cannot be excluded that relief of valvular obstruction, even if only moderate by conventional criteria, may have beneficial effects on morbidity and mortality in patients with PS AS.…”

“…As outlined above, these findings are consistent with the fact that an increased hemodynamic burden is less well tolerated by a poorly functioning ventricle than by a normal ventricle. In light of these recent data (66)(67)(68), every effort should be made to avoid prosthesis-patient mismatch in the patients with low-flow AS. The clinical implications of these findings are important given that prosthesis-patient mismatch is frequent (20% to 30%) after AVR and, as opposed to other risk factors, it can largely be avoided or its severity can be reduced with the use of a prospective strategy at the time of operation (36,(70)(71)(72)(73)(74).…”