Cardiac Pathology After Isolated Valve Replacement for Aortic Stenosis in Relation to Preoperative Patient Status: Early and Late Autopsy Findings

Abstract

Autopsy was performed on 51 (65%) of 79 patients who underwent valve replacement for aortic stenosis in 1965–1973 and died 0 days to 14 years (mean 3.2 years) later. Heart weight index (HWI) at autopsy averaged 356±94 g/m² and left ventricular wall thickness (LVWT) 19±4 mm. Macroscopic scattered streaky fibrosis (SSF) of the left ventricle was absent in 10% of the cases, slight in 31% and moderate/severe in 59%. Circumscript fibrotic scars were found in 31% and moderate/severe coronary artery disease (CAD) in 33%. All hearts were enlarged (HWI>200 g/m²), primarily due to residual left ventricular hypertrophy (LVWT>14 mm), which was present in 86% of cases. Both SSF and circumscript scars were unrelated to CAD. The preoperative predictability of autopsy findings was studied with multiple regression analyses. Predictive factors were as follows. For high HWI: high left ventricular end-diastolic pressure, short operation-autopsy time (O-A time) and high ECG hypertrophy score (ECG-hyp). For high LWT value: high cardiothoracic index (CTI), high transvalvular peak-systolic gradient and NYHA class II-III (vs. class IV). For moderate/severe SSF: high CTI and left ventricular failure. For moderate/severe CAD: short O–A time, narrow pulse pressure and low ECG-hyp. Although separated by valve replacement and a time span of up to 14 years, cardiac pathology at autopsy and preoperative patient/heart status were closely interrelated, thus emphasizing the significance of preoperatively impaired cardiac functional status and its relation to irreversible myocardial damage. The results advocate early operative intervention in aortic stenosis.

Key Words:

• aortic valve stenosis
• heart valve surgery
• cardiac pathology
• myocardial hypertrophy
• myocardial fibrosis