Abstract 11100: Difference in Clinical Characteristics, Left Atrial Reverse Remodeling and Functional Outcomes After Mitral Valve Replacement in Patients With Low-Gradient Very Severe Mitral Stenosis

Abstract

Introduction: The discrepancy between planimetered mitral valve area (MVA) and mean diastolic pressure gradient (MDPG) has not been studied extensively in patients with mitral stenosis (MS). Hypothesis: The purpose of the current study was to investigate the difference in characteristics and outcomes after mitral valve replacement (MVR) between low and high MDPG groups in very severe MS patients. Methods: This study evaluated 140 patients who received isolated MVR due to very severe MS (planimetered MVA ≤ 1.0 cm2) and performed follow-up echocardiography at least 12 months after MVR. Patients were divided into two groups according to preoperative MDPG (Low-gradient, < 10 mmHg; High-gradient, ≥ 10 mm Hg). Strain and strain rate analysis was performed using speckle tracking echocardiography before MVR in 56 patients. Results: There were 82 patients in low-gradient group and 58 patients in high-gradient group. The low-gradient group was older and demonstrated higher prevalence of female gender, diabetes mellitus, and atrial fibrillation (all p <0.05). When comparing the low-gradient and high-gradient groups, the left atrial volume index was larger (LAVI, 105.1 ± 51.9 ml/m2 vs. 87.8 ± 42.9 ml/m2, p < 0.001) and strain rate during isovolumic relaxation was lower (0.17 ± 0.08 s-1 vs. 0.29 ± 0.09 s-1, p < 0.001) in low-gradient group. After MVR, the percentage in LAVI reduction after MVR was significantly smaller in low-gradient group (-29.9 ± 15.1% vs. -43.5 ± 16.4%, p < 0.001). Persistent symptoms after MVR was more common in the low-gradient group compared to the high-gradient group (p = 0.004), even though preoperative functional class was similar between the groups. Conclusions: Low-gradient very severe MS was common in the population of high prevalence in diastolic dysfunction, such as the elderly, women, diabetes mellitus, and atrial fibrillation, was associated with impaired myocardial isovolumic relaxation, and demonstrated unfavorable left atrial reverse remodeling and a greater risk of persistent symptoms after MVR. These data might suggest the importance of concurrent management of diastolic dysfunction in low-gradient very severe MS.