Symptoms and natural history in patients with isolated severe calcific mitral stenosis
Authors: Kato N , Padang R , Scott C.G , Guerrero M , Pislaru S.V , Pellikka P.A 
Published: November 2020

Abstract

Background
Prevalence of calcific mitral stenosis (MS) increases with age. Mitral valve interventions for calcific MS are often delayed until symptoms are severely limiting because the natural history of calcific MS and its relation to cardiac symptoms or comorbidities have not been well assessed.

Objectives
We assessed the prevalence of symptoms, comorbidities and determinants of all-cause mortality in patients with severe calcific MS.

Methods
We retrospectively investigated adults with echocardiographic isolated severe MS, defined as mitral valve area (MVA by the continuity equation) ≤1.5 cm2, from July 2003 to December 2017. Among them, calcific MS was identified as obstruction of left ventricular inflow due to degenerative calcification of the mitral annulus using echocardiography and, whenever available, operative findings including histopathological examination. Inactivity was defined as requirement for assistance with activities of daily living. Follow up was obtained by review of medical records.

Results
Of 491 patients with isolated severe MS, calcific MS was present in 200 (41%; age 78±11 years, 18% men, 32% with atrial fibrillation). Charlson Comorbidity Index (CCI) was 5.1±1.7 and 14 (7%) were inactive. MVA and transmitral gradient (TMG) were 1.26±0.19 cm2 and 8.1±3.8 mmHg, respectively. Symptoms were present at baseline in 120 (60%) including dyspnea in 97, chest discomfort in 12, syncope in 3, lower extremity edema in 3, thrombosis in 3 and fatigue in 2. Of them, mitral valve interventions including surgical or transcatheter mitral valve replacement and mitral valve bypass were performed in 27 (23%): within 1 year after index TTE in 23 (19%) and at 2, 4, 5 and 6 years in 1 each. Of 80 patients without symptoms at index TTE, 20 (25%) developed symptoms at mean 2.9±3.2 years and interventions were performed in 5 (6%). Of 168 who did not receive interventions, 60 (36%) did not develop symptoms during follow up, 58 (35%) were considered to have moderate MS, 46 (27%) were not offered surgery because of high risk due to advanced age, multiple comorbidities or heavy calcification, and 2 (1%) declined interventions. During follow-up of 2.8±3.0 years, Kaplan-Meier survival at 1 and 3 years without intervention were 72% and 52%, respectively (Fig. A). Inactivity, CCI &gt;5, left ventricular ejection fraction (LVEF) &lt;50%, TMG ≥8 mmHg (the mean TMG) and right ventricular systolic pressure (RVSP) ≥50 mmHg were independently associated with mortality (Fig. B). Symptoms were associated with referral for interventions (OR 3.43, 95% CI 1.22–9.65; p=0.019), but not with mortality.

Conclusion
Patients with isolated severe calcific MS had a high burden of comorbidities and had high mortality without intervention. Symptoms were common (60%), but were not associated with mortality. TMG ≥8 mmHg, RVSP ≥50 mmHg, LVEF&lt;50%, CCI &gt;5 and inactivity were independently associated with mortality.

Funding Acknowledgement
Type of funding source: None