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Prognostic value of coronary and microvascular flow reserve in patients with nonischemic dilated cardiomyopathy
Marta F Lima1, Wilson Mathias, João C N Sbano
1Heart Institute, University of São Paulo Medical School, São Paulo, Brazil.
Insights
In nonischemic dilated cardiomyopathy, increased left atrial diameter and depressed beta reserve (β reserve) are key predictors of cardiac events. Beta reserve from real-time myocardial perfusion echocardiography (RTMPE) offers valuable prognostic information.
Area of Science:
- Cardiology
- Echocardiography
- Cardiovascular Imaging
Background:
- Coronary and microvascular blood flow reserve are established prognostic markers in cardiovascular disease.
- Non-ischemic dilated cardiomyopathy (NICM) carries a significant risk of adverse cardiac events.
- Assessing prognostic factors in NICM is crucial for guiding clinical management.
Purpose of the Study:
- To evaluate the prognostic value of coronary flow velocity reserve (CFVR) and real-time myocardial perfusion echocardiography (RTMPE) in patients with NICM.
- To identify independent predictors of cardiac events in this patient population.
Main Methods:
- A prospective study of 195 patients with NICM (LVEF < 35%) undergoing dipyridamole stress RTMPE.
- Coronary flow velocity reserve (CFVR) was calculated from distal left anterior coronary artery velocities.
- RTMPE parameters including replenishment velocity (β), plateau of acoustic intensity (A(N)), and myocardial blood flow reserve were assessed.
Main Results:
- Mean CFVR was 2.07 ± 0.52, mean β reserve was 2.05 ± 0.39.
- During a median 29-month follow-up, 45 events (deaths or urgent transplantations) occurred.
- Independent predictors of events were increased left atrial diameter and depressed β reserve (≤ 2.0). CFVR and myocardial blood flow reserve lost predictive value after adjustment for β reserve.
Conclusions:
- Increased left atrial diameter and depressed β reserve are independent predictors of cardiac death and transplantation in NICM patients.
- β reserve assessed by RTMPE provides incremental prognostic value beyond established clinical and echocardiographic factors.
- RTMPE is a valuable tool for risk stratification in non-ischemic dilated cardiomyopathy.
Background:
Coronary and microvascular blood flow reserve have been established as important predictors of prognosis in patients with cardiovascular disease. The aim of this study was to assess the value of coronary flow velocity reserve (CFVR) and real-time myocardial perfusion echocardiography (RTMPE) for predicting events in patients with nonischemic dilated cardiomyopathy.
Methods:
One hundred ninety-five patients (mean age 54 ± 12 years; 66% men) with dilated cardiomyopathy (left ventricular ejection fraction < 35% and no obstructive coronary disease on invasive angiography or multidetector computed tomography) who underwent dipyridamole stress (0.84 mg/kg over 10 min) RTMPE were prospectively studied. CFVR was calculated as the ratio of hyperemic to baseline peak diastolic velocities in the distal left anterior coronary artery. The replenishment velocity (β), plateau of acoustic intensity (A(N)), and myocardial blood flow reserve were obtained from RTMPE.
Results:
Mean CFVR was 2.07 ± 0.52, mean A(N) reserve was 1.05 ± 0.09, mean β reserve was 2.05 ± 0.39, and mean myocardial blood flow reserve (A(N) × β) was 2.15 ± 0.48. During a median follow-up period of 29 months, 45 patients had events (43 deaths and two urgent transplantations). Independent predictors of events were left atrial diameter (relative risk, 1.16; 95% confidence interval, 1.08-1.26; P < .001) and β reserve ≤ 2.0 (relative risk, 3.22; 95% confidence interval, 1.18-8.79; P < .001). After adjustment for β reserve, CFVR and myocardial blood flow reserve no longer had predictive value. Left atrial diameter added prognostic value over clinical factors and left ventricular ejection fraction (χ2 = 36.8-58.5, P < .001). Beta reserve added additional power to the model (χ2 = 70.2, P < .001).
Conclusions:
Increased left atrial diameter and depressed β reserve were independent predictors of cardiac death and transplantation in patients with nonischemic dilated cardiomyopathy. Beta reserve by RTMPE provided incremental predictive value beyond that provided by current known prognostic clinical and echocardiographic factors.
