Degenerative Mitral Stenosis Versus Rheumatic Mitral Stenosis

Mitral stenosis is classically caused by rheumatic disease (RMS). However, degenerative mitral stenosis (DMS) is increasingly encountered, particularly in developed countries with aging populations. The aim of this study was to compare clinical and echocardiographic characteristics between the 2 entities. One hundred fifteen patients with DMS were identified from an echocardiographic database in the United States and compared with 510 patients with RMS from Seoul, Korea. All subjects had a mitral valve area (MVA) ≤2.5 cm² by continuity equation but were otherwise unselected. Patients with DMS were older and had more hypertension, diabetes, chronic kidney disease, and chronic obstructive pulmonary disease than those with RMS. Atrial fibrillation was more common in RMS patients. Mean mitral valve gradient was slightly lower in DMS versus RMS (7.63 ± 3.67 vs 8.50 ± 4.23 mm Hg, p = 0.04) but MVA was strikingly higher in the DMS group (1.35 ± 0.41 vs 0.95 ± 0.38 cm², p <0.0001). This appeared to be due to greater stroke volume in the DMS patients (70.4 ± 19.7 vs 55.7 ± 15.5 ml, p <0.0001). Indexed left atrial volume was greater in RMS (82.1 ± 40.3 vs 57.9 ± 21.4 ml, p <0.0001) while estimated pulmonary artery systolic pressure was greater in DMS (49.3 ± 16.5 vs 39.4 ± 13.6 mm Hg, p <0.0001). In conclusion, DMS patients are older and have more comorbidities than RMS patients. DMS presents with greater MVA relative to mean mitral valve gradient than RMS. This appears due to a higher stroke volume in DMS patients.