Clinical Outcome of Degenerative Mitral Regurgitation: Critical Importance of Echocardiographic Quantitative Assessment in Routine Practice
Background—Echocardiographic quantitation of degenerative mitral regurgitation (DMR) is recommended whenever possible in clinical guidelines but is criticized and its scalability to routine clinical practice doubted. We hypothesized that echocardiographic DMR quantitation, performed in routine clinical practice by multiple practitioners predicts independently long-term survival, and thus is essential to DMR management.
Methods—We included patients diagnosed with isolated mitral-valve-prolapse 2003-2011 and any degree of MR quantified by any physician/sonographer in routine clinical practice. Clinical/echocardiographic data acquired at diagnosis were retrieved electronically. Endpoint was mortality under medical treatment analyzed by Kaplan-Meir method and Proportional-Hazard models.
Results—The cohort included 3914 patients (55% male) aged 62±17 years, with left ventricular ejection fraction (LVEF) 63±8% and routinely measured effective regurgitant orifice area (EROA) 19[0-40] mm2. During follow-up (6.7±3.1 years) 696 patients died under medical management and 1263 underwent mitral surgery. In multivariate analysis, routinely measured EROA was associated with mortality (adjusted-hazard-ratio 1.19[1.13-1.24] p<0.0001 per-10mm2) independently of LVEF and end-systolic diameter, symptoms and age/comorbidities. The association between routinely measured EROA and mortality persisted with competitive risk modeling (adjusted hazard-ratio 1.15[1.10-1.20] per 10mm2 p<0.0001), or in patients without guideline-based Class I/II surgical triggers (adjusted hazard ratio 1.19[1.10-1.28] per 10mm2 p<0.0001) and in all subgroups examined (all p<0.01). Spline curve analysis showed that, compared with general population mortality, excess mortality appears for moderate DMR (EROA ≥20mm2) becomes notable ≥EROA 30mm2 and steadily increases with higher EROA levels, > 40 mm2 threshold.
Conclusions—Echocardiographic DMR quantitation is scalable to routine practice and is independently associated with clinical outcome. Routinely measured EROA is strongly associated with long-term survival under medical treatment. Excess mortality vs. the general population appears in the "moderate" DMR range and steadily increases with higher EROA. Hence, individual EROA values should be integrated into therapeutic considerations, additionally to categorical DMR grading.
- Received December 9, 2017.
- Revision received April 23, 2018.
- Accepted May 16, 2018.