Impact of Valve Prosthesis-Patient Mismatch on Intermediate-term Outcome and Regression of Left Ventricular Mass Following Aortic Valve Replacement with Mechanical Prosthesis

Impact of Prosthesis-Patient Mismatch After Surgical Aortic Valve Replacement: Systematic Review and Meta-Analysis of Reconstructed Time-to-Event Data of 122 989 Patients With 592 952 Patient-Years

BACKGROUND

It remains controversial whether prosthesis-patient mismatch (PPM) impacts long-term outcomes after surgical aortic valve replacement. We aimed to evaluate the association of PPM with mortality, rehospitalizations, and aortic valve reinterventions.

METHODS AND RESULTS

We performed a systematic review with meta-analysis of reconstructed time-to-event data of studies published by March 2023 (according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses). Sixty-five studies met our eligibility criteria and included 122 989 patients (any PPM: 68 332 patients, 55.6%). At 25 years of follow-up, the survival rates were 11.8% and 20.6% in patients with and without any PPM, respectively (hazard ratio [HR], 1.16 [95% CI, 1.13-1.18], P<0.001). At 20 years of follow-up, the survival rates were 19.5%, 12.1%, and 8.8% in patients with no, moderate, and severe PPM, respectively (moderate versus no PPM: HR, 1.09 [95% CI, 1.06-1.11], P<0.001; severe versus no PPM: HR, 1.29 [95% CI, 1.24-1.35], P<0.001). PPM was associated with higher risk of cardiac death, heart failure-related hospitalizations, and aortic valve reinterventions over time (P<0.001). Statistically significant associations between PPM and worse survival were observed regardless of valve type (bioprosthetic versus mechanical valves), contemporary PPM definitions unadjusted and adjusted for body mass index, and PPM quantification method (in vitro, in vivo, Doppler echocardiography). Our meta-regression analysis revealed that populations with more women tend to have higher HRs for all-cause death associated with PPM.

CONCLUSIONS

The results of the present study suggest that any degree of PPM is associated with poorer long-term outcomes following surgical aortic valve replacement and provide support for implementation of preventive strategies to avoid PPM after surgical aortic valve replacement.

A critical review of hemodynamic changes and left ventricular remodeling after surgical aortic valve replacement and percutaneous aortic valve replacement

The introduction of transcatheter aortic valve replacement (TAVR) in clinical practice has widened options for symptomatic patients at high surgical risk; however, it is not known whether TAVR has equivalent or prolonged benefits in terms of left ventricular (LV) remodeling.

METHODS

To explore the relative hemodynamic benefits and postoperative LV remodeling associated with TAVR and surgical aortic valve replacement (SAVR), we performed a critical review of the available literature. A total of 67 studies were included in this systematic review.

RESULTS

There is at least equivalent if not slightly superior hemodynamic performance of TAVR over SAVR, and TAVR showed lower prosthesis-patient mismatch compared with SAVR. However, LV mass appears to regress to a greater degree after SAVR compared with TAVR. Aortic regurgitation, paravalvular in particular, is more common after TAVR than SAVR, although it is rarely more than moderate in severity. Improvements in diastolic function and mitral regurgitation are reported in only a handful of studies each and could not be compared across prosthesis types.

CONCLUSIONS

The published data support the hemodynamic comparability of SAVR and TAVR, with the higher incidence of prosthesis-patient mismatch in SAVR offset by higher incidence of paravalvular leak in TAVR. These results highlight the need for further studies focusing on hemodynamic changes after valve therapy.

Update on aortic valve prosthesis-patient mismatch in Japan

The influence of aortic valve prosthesis-patient mismatch (VP-PM) on the clinical outcome has been an ongoing controversy. The reported prevalence of VP-PM after aortic valve replacement (AVR) ranges widely between 20 and 70 %. The inconsistent impact of VP-PM on short-term and long-term mortality, regression of left ventricular (LV) hypertrophy, and exercise capacity may be explained by differences of the patient populations, the definition of VP-PM, and the use of different prostheses. Moreover, many factors other than the severity of VP-PM should be taken into account when considering its impact on individual patients after AVR. Although the concept of VP-PM is easy to understand, it cannot be applied to the whole patient population. In Japan, the age of the candidates for AVR has increased markedly in recent years, but almost all elderly patients with a small BSA (<1.6 m(2)) have received newer-generation prostheses with a small outer diameter and large effective orifice area. Indeed, previous studies of Japanese patients have demonstrated that VP-PM was no more than moderate in most cases and its impact on clinical outcomes was generally acceptable. Although severe VP-PM is infrequent and its clinical implications are still unproven in elderly Japanese patients, it would seem reasonable to try to prevent severe VP-PM. Thus, VP-PM itself cannot be accepted as an independent risk factor in Japanese patients, but the useful preventive strategies for severe VP-PM in inactive very elderly persons remain controversial. The implantation of newer-generation biological or mechanical prostheses with or without aortic annular enlargement should be considered according to the characteristics of the patient and the risk-benefit ratio for carrying out a particular procedure in an individual patient.

Enhanced left ventricular mass regression after aortic valve replacement in patients with aortic stenosis is associated with improved long-term survival

BACKGROUND

Aortic valve replacement in patients with aortic stenosis is usually followed by regression of left ventricular hypertrophy. More complete resolution of left ventricular hypertrophy is suggested to be associated with superior clinical outcomes; however, its translational impact on long-term survival after aortic valve replacement has not been investigated.

METHODS

Demographic, operative, and clinical data were obtained retrospectively through case note review. Transthoracic echocardiography was used to measure left ventricular mass preoperatively and at annual follow-up visits. Patients were classified according to their reduction in left ventricular mass at 1 year after the operation: group 1, less than 25 g; group 2, 25 to 150 g; and group 3, more than 150 g. Kaplan-Meier and multivariable Cox regression were used.

RESULTS

A total of 147 patients were discharged from the hospital after aortic valve replacement for aortic stenosis between 1991 and 2001. Preoperative left ventricular mass was 279 ± 98 g in group 1 (n = 47), 347 ± 104 g in group 2 (n = 62), and 491 ± 183 g in group 3 (n = 38) (P < .001). Mean time to last echocardiogram was 6.2 ± 3.2 years. Left ventricular mass at late follow-up was 310 ± 119 g in group 1, 267 ± 107 g in group 2, and 259 ± 96 g in group 3 (P = .05). Transvalvular gradients at follow-up were not significantly different among the groups (group 1, 24.8 ± 23 mm Hg; group 2, 21.4 ± 16 mm Hg; group 3, 14.7 ± 9 mm Hg) (P = .31). There was no difference in the prevalence of other factors influencing left ventricular mass regression such as ischemic heart disease or hypertension, valve type, or valve size used. Ten-year actuarial survival was not statistically different in patients with enhanced left ventricular mass regression when compared with the log-rank test (group 1, 51% ± 9%; group 2, 54% ± 8%; and group 3, 72% ± 10%) (P = .26). After adjustment, left ventricular mass reduction of more than 150 g was demonstrated as an independent predictor of improved long-term survival on multivariate analysis (P = .02).

CONCLUSIONS

Our study is the first to suggest that enhanced postoperative left ventricular mass regression, specifically in patients undergoing aortic valve replacement for aortic stenosis, may be associated with improved long-term survival. In view of these findings, strategies purported to be associated with superior left ventricular mass regression should be considered when undertaking aortic valve replacement.