Aortic valve replacement in patients with aortic valve stenosis improves myocardial metabolism and diastolic function.

Abstract

To evaluate whether functional and metabolic changes recover after aortic valve replacement (AVR). Eighteen men with aortic valve stenosis (mean pressure gradient +/- SD, 79.9 mm Hg +/- 15.1) underwent magnetic resonance (MR) imaging and phosphorus 31 MR spectroscopy. In nine patients who underwent AVR, MR imaging and spectroscopy were repeated 40 weeks +/- 12 after AVR. Ten age-matched healthy men were control subjects. Before AVR, the myocardial phosphocreatine (PCr)-to-adenosine triphosphate (ATP) ratio in the 18 patients was 1.24 +/- 0.17 and 1.43 +/- 0.14 in the control group (P <.01). In nine patients who underwent follow-up MR spectroscopy, the ratio increased from 1.28 +/- 0.17 to 1.47 +/- 0.14 (P <.05) following AVR. Before AVR, early acceleration peak corrected for cardiac output was (0.043 +/- 0.008) x 10(-3) sec(-1) in patients and (0.081 +/- 0.033) x 10(-3) sec(-1) in the control group (P <.05). After 40 weeks +/- 12, the mean early acceleration peak corrected for cardiac output in the nine patients increased significantly to (0.055 +/- 0.006) x 10(-3) sec(-1) (P <.05), although it was still significantly lower than that of the control group (P <.05). Before AVR, a significant correlation was found between the myocardial PCr-ATP ratio and left ventricular diastolic function (n = 18; P <.05). Severe aortic valve stenosis leads to a decreased myocardial PCr-ATP ratio and impairment of left ventricular diastolic function; following AVR, the ratio normalizes completely, whereas function improves significantly. There is an association between altered myocardial high-energy phosphate metabolism and impaired left ventricular diastolic function.