Indexed effective orifice area after mechanical aortic valve replacement does not affect left ventricular mass regression in elderly

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.

Clinical outcomes and hemodynamics of the 19-mm Perimount Magna bioprosthesis in an aortic position: comparison with the 19-mm Medtronic Mosaic Ultra Valve

BACKGROUND

When aortic valve replacement is performed in patients with a small aortic annulus, prosthesis-patient mismatch (PPM) is of concern because it can affect postoperative clinical outcomes. Although larger bioprosthetic valves have been well studied, the hemodynamics of 19-mm bioprostheses have been reported in only a small number of patients. The effectiveness as well as the impact of PPM on outcomes are thus still unclear.

METHODS AND RESULTS

Postoperative clinical and hemodynamic variables were compared in 67 patients with a 19-mm Carpentier Edwards Perimount Magna bioprosthesis and in 10 patients with a 19-mm Medtronic Mosaic Ultra valve. Mean follow-up time was 13 months. There was no in-hospital mortality. Echocardiography 6.5±4.0 months after surgery showed significant decreases in the mean left ventricular (LV)-aortic pressure gradient, and decreases in the mean LV mass index. Reduction in LV mass index did not differ between the valve groups, despite a higher pressure gradient in the Mosaic group. Although PPM was detected in 21 patients in the Magna group, it did not affect regression of the LV mass index during the follow-up period.

CONCLUSIONS

Use of the 19-mm Magna bioprosthesis appears to provide satisfactory clinical results. LV-aortic pressure gradient was lower in the Magna group. The present data suggest that PPM is not related to reduction in the LV mass index.

Hemodynamics and Outcomes of Aortic Valve Replacement with a 17- or 19-mm Valve

When aortic valve replacement is performed in patients with a small aortic annulus, prosthesis-patient mismatch is of concern because it may affect postoperative clinical status. We conducted a retrospective study of outcomes in 65 patients with aortic stenosis requiring valve replacement. Fifty were given a 17-mm or 19-mm St. Jude Regent mechanical valve, and 15 were given a 19-mm Medtronic Mosaic bioprosthesis. Echocardiography was carried out preoperatively, at discharge, and at follow-up. There was 1 (2%) operative death in the Regent group and none in the Mosaic group. There was no valve-related event. Follow-up echocardiography in both groups revealed a significant increase in the mean effective orifice area index, a decrease in the mean left ventricular-aortic pressure gradient, and a decrease in the mean left ventricular mass index. Prosthesis-patient mismatch (effective orifice area index <0.85 cm2 · m−2) existed in 13 (26%) patients in the Regent group and 11 (73%) in the Mosaic group at discharge. All patients improved to New York Heart Association functional class II or better. A small-sized prosthesis may provide satisfactory clinical and hemodynamic results in patients with a small aortic annulus.

Cardiac Mechanics Revisited

The keynote to understanding cardiac function is recognizing the underlying architecture responsible for the contractile mechanisms that produce the narrowing, shortening, lengthening, widening, and twisting disclosed by echocardiographic and magnetic resonance technology. Despite background knowledge of a spiral clockwise and counterclockwise arrangement of muscle fibers, issues about the exact architecture, interrelationships, and function of the different sets of muscle fibers remain to be resolved. This report (1) details observed patterns of cardiac dynamic directional and twisting motions via multiple imaging sources; (2) summarizes the deficiencies of correlations between ventricular function and known ventricular muscle architecture; (3) correlates known cardiac motions with the functional anatomy within the helical ventricular myocardial band; and (4) defines an innovative muscular systolic mechanism that challenges the previously described concept of “isovolumic relaxation.” This new knowledge may open new doors to treating heart failure due to diastolic dysfunction.

Aortic valve replacement for aortic stenosis in the elderly: influence of prosthesis-patient mismatch on late survival and left ventricular mass regression

PURPOSE

Controversy still exists about the influence of prosthesis-patient mismatch on outcomes after aortic valve replacement in the elderly. Our aim was to evaluate the effect of prosthesis-patient mismatch on survival and the extent of left ventricular (LV) mass regression after aortic valve replacement for aortic stenosis in Japanese patients aged >or=65 years.

MATERIALS AND METHODS

A total of 84 patients who underwent isolated aortic valve replacement for aortic stenosis between 1986 and 2006 were retrospectively analyzed. Patients were divided into two groups based on the definition of prosthesis-patient mismatch (indexed effective orifice area <or=0.85 cm(2)/m(2)), and long-term results were compared. The mean follow-up time was 4.5 +/- 4.5 years. In 49 patients, follow-up echocardiography was performed at least 6 months after surgery, and the extent of LV mass regression was analyzed according to the presence of a prosthesis-patient mismatch.

RESULTS

Eight years after surgery, there was no significant difference between patients with and without mismatch in terms of actuarial freedom from cardiac-related death (P = 0.159) or death from any valve-related events (P = 0.107). The postoperative transvalvular pressure gradients were not significantly different between the two groups, and significant absolute and relative LV mass regression were observed in both groups.

CONCLUSION

Although a moderate prosthesis-patient mismatch appeared to be tolerable, the criteria of prosthesis-patient mismatch may have to be reassessed for elderly Japanese patients.

Impact of Valve Prosthesis-Patient Mismatch on Long-Term Survival and Left Ventricular Mass Regression After Aortic Valve Replacement for Aortic Stenosis

BACKGROUND AND AIM OF THE STUDY

The influence of prosthesis-patient mismatch on long-term results after aortic valve replacement remains controversial. The aim of this study was to evaluate the effect of prosthesis-patient mismatch on survival and the extent of left ventricular mass regression after aortic valve replacement for aortic stenosis.

METHODS

We retrospectively reviewed 146 patients who underwent isolated aortic valve replacement for aortic stenosis between 1990 and 2005. Prosthesis-patient mismatch was defined as an effective orifice area/body surface area <or=0.85 cm(2)/m(2). Mean follow-up was 4.5 +/- 3.3 years, with a total follow-up of 650.0 patient-years. In 108 patients, follow-up echocardiography was performed at least 6 months after surgery, and the extent of postoperative left ventricular mass regression was analyzed according to the presence of prosthesis-patient mismatch.

RESULTS

Ten years after surgery, there was no significant difference between patients with mismatch and those without mismatch in overall survival (p = 0.345), actuarial freedom from cardiac-related death (p = 0.576), and freedom from any valve-related mortality or morbidity (p = 0.614). Using multivariate analysis, PPM was not a predictor of late cardiac-related death or all deaths. Echocardiographic examination showed that left ventricular wall thickness and left ventricular mass was significantly decreased postoperatively in both groups. However, the absolute and relative left ventricular mass regression was significantly lower in patients with mismatch than in those without mismatch.

CONCLUSIONS

This study showed no negative effects of prosthesis-patient mismatch on survival at 10 years after aortic valve replacement for aortic stenosis. However, the extent of left ventricular mass regression was significantly lower in patients with mismatch.