Regurgitant Volume Informs Rate of Progressive Cardiac Dysfunction in Asymptomatic Patients With Chronic Aortic or Mitral Regurgitation | Journal Scan
In asymptomatic patients with moderate to severe aortic regurgitation (AR) or mitral regurgitation (MR), does regurgitant volume index correlate with left ventricular (LV) dysfunction?
In an observational cohort study, 130 consecutive asymptomatic patients with moderate to severe MR and 130 patients with moderate to severe asymptomatic AR who underwent exercise echocardiography were matched according to age and regurgitant volume index. Regurgitation severity was determined using quantitative Doppler (the difference between valve stroke volume and systemic stroke volume); severe regurgitation was defined as a regurgitant volume index ≥30 ml/m2. All patients underwent yearly echocardiographic follow-up.
During follow-up, regardless of etiology (AR vs. MR), patients with severe regurgitation demonstrated increasing LV volume index (4.2 ± 1.5 ml/m2 per year; p = 0.01) and decreasing LV ejection fraction (1.3 ± 0.4% per year; p = 0.002). In patients with moderate regurgitation, LV volume and ejection fraction did not significantly change. In addition, independent of regurgitation etiology, patients with severe regurgitation experienced a similar drop in contractility (end-systolic pressure/end-systolic volume ratio and single-beat preload recruitable stroke work) during follow-up. Contractility parameters did not change in patients with moderate regurgitation.
Asymptomatic patients with moderate AR or MR had stable cardiac function during 3 years of follow-up; the authors concluded that frequent echocardiography may not be necessary in the absence of change in clinical status. In the setting of severe regurgitation, LV deterioration occurred at a similar rate and manner regardless of whether there was underlying AR or MR.
The authors note that frequent monitoring of asymptomatic patients with moderate AR or MR might be unnecessary, but also found a progressive decrease in LV performance among asymptomatic patients with severe AR or MR. One role for periodic monitoring would be to screen for progression to severe regurgitation. Methodological issues with the study might include some degree of selection bias (absence of ‘prophylactic’ mitral valve repair among patients with severe MR, a presumably small subset of patients who underwent exercise echo, and substantial attrition after 1 year due to surgery or loss to follow-up), the use of quantitative Doppler for isolated assessment of regurgitation severity, and the assessment of LV contractility using noninvasively derived variables of end-systolic pressure-volume ratio and single-beat preload recruitable stroke work. The finding of progressive decline in LV performance among asymptomatic patients with severe MR or AR, presumably in the absence of a clinical indication for intervention, is troublesome if accurate.
Keywords: Aortic Valve Insufficiency, Blood Pressure, Echocardiography, Doppler, Mitral Valve Insufficiency, Selection Bias, Stroke Volume, Ventricular Dysfunction, Left, Ventricular Function, Left
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