Myocardial metabolism and diastolic function after aortic valve replacement for aortic stenosis: influence of patient-prosthesis mismatch.

Objective: This study evaluated the impact of patient-prosthesis mismatch on myocardial function and high-energy phosphate metabolism after aortic valve replacement for pure aortic stenosis. Patients with and without patient-prosthesis mismatch were compared using magnetic resonance techniques.

Methods: Thirty patients who had undergone aortic valve replacement with Medtronic Mosaic bioprosthesis were evaluated. Fifteen patients with patient-prosthesis mismatch were compared to 15 matched patients without patient-prosthesis mismatch. These two homogeneous groups were studied for myocardial metabolism and left ventricle function preoperatively and at 12 months postoperatively with magnetic resonance imaging and (31)P spectroscopy.

Results: All patients experienced improvement in myocardial metabolism and left ventricle function. Left ventricle mass regression was impaired in both groups. Impaired diastolic filling was associated with increased left ventricle wall mass in both groups (patient-prosthesis mismatch: R(2) = -0.71, p = 0.002; no patient-prosthesis mismatch: R(2) = -0.88, p < 0.001). Myocardial phosphocreatine/adenosine triphosphate ratio revealed a modest correlation with left ventricle function as evaluated by early acceleration peak (patient-prosthesis mismatch: R(2) = 0.37, p = 0.03; no patient-prosthesis mismatch: R(2) = 0.17, p = 0.02) and early deceleration peak (patient-prosthesis mismatch: R(2) = 0.30, p = 0.01; no patient-prosthesis mismatch: R(2) = 0.39, p = 0.008). No significant correlation between the phosphocreatine/adenosine triphosphate ratio and left ventricle mass was found (patient-prosthesis mismatch: R(2) = 0.39, p = 0.6; no patient-prosthesis mismatch: R(2) = 0.40, p = 0.08).

Conclusion: Aortic valve replacement leads to early improvement of left ventricle function and myocardial metabolism in all patients regardless of the occurrence of patient-prosthesis mismatch.