Cardiac damage extent in patient with isolated severe aortic stenosis referred to surgical aortic valve replacement: is it reversible after surgery?

Abstract

Abstract Background Aortic stenosis (AS) may lead to progressive and adverse cardiac remodeling. A recently-proposed staging classification regarding extravalvular cardiac damage in AS patients undergoing aortic valve intervention was shown to have significant prognosis implications. However, cardiac damage evolution and reversibility after intervention remain unknown. Aims to assess extravalvular cardiac damage evolution after surgical aortic valve replacement (SAVR) in patients with isolated severe AS. Methodology we performed a single-center, prospective cohort study enrolling consecutive patients with severe aortic stenosis undergoing SAVR. Those with previous cardiomyopathy or concomitant severe valve dysfunction beyond AS were excluded. All patients performed transthoracic echocardiogram (TTE) and cardiac magnetic resonance (CMR) within 3 months before SAVR as well as at the 3rd to 6th post-operative month. Patients were classified according to the extent of cardiac damage into 4 groups: stage 0: no damage; stage 1: left ventricle (LV) hypertrophy (indexed LV mass >95 g/m2 [women] or >115 g/m2 [men]), LV diastolic (E/e′ > 14) or systolic (ejection fraction <50%) dysfunction; stage 2: dilated left atrium (>34mL/m2) or atrial fibrillation; stage 3: pulmonary hypertension (systolic pulmonary artery pressure ≥60mmHg); stage 4: significant right ventricle (RV) dysfunction. Global longitudinal strain (GLS) was also assessed to further characterize the extent of LV damage – a GLS > -14.7% was considered abnormal. Due to the impact of on-pump cardiac surgery on RV systolic longitudinal function, RV ejection fraction assessed by CMR (<45%) was used to define significant post-operative RV dysfunction. Results A total of 67 patients were included (mean age 71 ± 8 years; 50% male; mean valvular transaortic gradient 60 ± 19 mmHg; mean indexed aortic valve area 0.4 ± 0.01 cm2/m2; mean LV ejection fraction by TTE 58 ± 9%). Overall, a significant number of patients still showed sign of structural cardiac damage after surgery – 14 vs. 10 on stage 1, 44 vs. 39 on stage 2, 1 vs. 1 on stage 3 and 4 vs. 4 on stage 4 after AVR- figure 1. However, a statistically significant improvement in the number of patients at stage 0 after surgery (4 vs. 11, paired McNemar test p=0.016) was observed, as well as a significant improvement in GLS (mean GLS pre and post AVR -14.8 ± 3.6% vs. -16.6 ± 3.3%, respectively; 45 vs. 21% patients with abnormal GLS before and after AVR, p=0.001). Conclusion Extravalvular cardiac damage is common in a selected cohort of severe AS and potentially reversible after SAVR. A significant improvement in GLS, although not a part of the previously established staging system, was observed after AVR. Whether or not these findings may correlate with long-term patient prognosis or if additional favorable cardiac remodeling is seen on a longer-term follow-up remains to be determined.