Abstract 18965: Monitoring the Asymptomatic Patient with Severe Mitral Regurgitation: Do Measuring LV Volumes Make a Difference in Predicting Mortality?

Abstract

Background: The ACC/AHA Valvular Heart Disease Guidelines include a class I recommendation for surgery in asymptomatic patients with chronic severe mitral regurgitation (MR) if the EF is ≤ 60% and/ or the end-systolic diameter (ESD) > 40 mm. However, the ESD has inherent limitations because it only detects changes in one dimension while LV volume can detect subtle changes in LV geometry in multiple dimensions. We sought to measure the impact of shifting from ESD to end systolic volume (ESV) in predicting mortality.

Methods: We performed a retrospective search of our single center echocardiography database over a 5 year period for all cases with severe (4+) MR. From this list of 240 patients, we reviewed the medical records to identify the subgroup of patients who remained asymptomatic at the time of echo evaluation (N = 61). Since the ACC/AHA Guidelines recommend surgical referral for asymptomatic patients with an EF ≤ 60%, these patients were also excluded in order to isolate the impact of LV size on mortality. This resulted in a total of 31 study subjects. Study subjects were classified according to 2 different methods: “classic” LV size criteria (ESD > 40mm) or “volume” LV size criteria (ESV ≥ “mildly dilated” per ASE Chamber Quantification Guidelines). Volumes were obtained using a biplane Simpson.

Results: As compared to classic LV size criteria using ESD, a change to volume criteria using ESV would significantly increases the percentage of patients identified with abnormal LV geometry (61% vs 25%, p < 0.01). However, despite identifying a larger number of patients with abnormal LV geometry, the difference in mortality using volume criteria or classic criteria was not significant.

Conclusion: Although there are conceptual advantages to the assessment of LV size using LV volumes rather than 2D linear measurements, the difference in the two methods for predicting mortality in the context of asymptomatic MR with normal EF was not significant. Further refinements in the assessment of LV volumes, larger studies, and inclusion of additional end-points such as CHF admissions may be needed to further understand the relationship between changes in LV geometry and adverse events in this population.