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Mitral Annular Calcification Mean Pressure Gradient and Prognosis
Quick Takes
- Among patients with mitral annular calcification (MAC), the mean transmitral gradient is associated with increased mortality after adjustment for age, sex, and MAC-related risk factors.
- In contrast, mitral regurgitation severity was associated with mortality only when associated with low transmitral gradients.
- It remains to be determined whether the transmitral gradient among patients with MAC is the cause of, or a marker for, increased all-cause mortality.
Study Questions:
What is the prognostic importance of the transmitral mean pressure gradient and the presence of mitral regurgitation (MR) among patients with mitral annular calcification (MAC)?
Methods:
A retrospective review of an institutional echocardiographic database was used to identify a total of 5,754 patients with MAC. Patients were divided by transmitral mean gradient as low (3-5 mm Hg, n = 3,927), medium (5-10 mm Hg, n = 1,476), and high (≥10 mm Hg, n = 351). The mean age was 78 ± 11 years, and 67% were women. MR was none/trace in 32%, mild in 42%, moderate in 23%, and severe in 3%. The primary outcome was all-cause mortality; outcome models were adjusted for age, sex, and risk factors related to MAC (hypertension, diabetes, coronary artery disease, chronic kidney disease).
Results:
Survival at 1, 5, and 10 years was 77%, 42%, and 18% in the low gradient group; 73%, 38%, and 17% in the mid gradient group; and 67%, 25%, and 11% in the high gradient group, respectively (log-rank p < 0.001 between groups). The mitral gradient was independently associated with mortality (adjusted hazard ratio, 1.064 per 1 mm Hg increase; 95% confidence interval, 1.049-1.080). MR severity was associated with mortality at low gradients (p < 0.001), but not at mid gradient (p = 0.17) or high gradient (p = 0.37).
Conclusions:
Among patients with MAC, mean transmitral gradient is associated with increased mortality after adjustment for age, sex, and MAC-related risk factors. Concomitant MR is associated with excess mortality among patients with MAC and low gradients (3-5 mm Hg), but loses its prognostic importance with higher transmitral gradients, which the authors conclude indicates the prognostic utility of transmitral gradients among patients with MAC regardless of MR severity.
Perspective:
MAC is a common degenerative condition that can be associated with mitral stenosis and MR, and itself is associated with adverse outcomes. This retrospective single-center study suggests that an increased transmitral gradient among patients with MAC is associated with worse all-cause mortality. The degree of MAC was not quantified (and admittedly might not be readily quantifiable on echocardiography); heart rate (which would be expected to affect the transmitral gradient) was not assessed; the transmitral gradient could be affected by factors in addition to the degree of mitral obstruction (including left ventricular diastolic function); and, like all retrospective studies, there is uncertainty about how well other factors potentially affecting mortality could be controlled for in the analysis. Although the findings are provocative, additional study is necessary to determine whether transmitral gradient among patients with MAC is the cause of, or a marker for, increased all-cause mortality.
Clinical Topics: Geriatric Cardiology, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Prevention, Valvular Heart Disease, Atherosclerotic Disease (CAD/PAD), Echocardiography/Ultrasound, Hypertension, Mitral Regurgitation
Keywords: Coronary Artery Disease, Diabetes Mellitus, Diagnostic Imaging, Diastole, Echocardiography, Geriatrics, Heart Valve Diseases, Hypertension, Kidney Diseases, Mitral Valve Insufficiency, Mitral Valve Stenosis, Risk Factors, Secondary Prevention, Ventricular Function, Left
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