Prevalence and Prognostic Significance of Left Ventricular Reverse Remodeling in Dilated Cardiomyopathy Receiving Tailored Medical Treatment

Study Questions:

What is the prevalence left ventricular reverse remodeling (LVRR) in dilated cardiomyopathy, and what prognostic significance does it confer?

Methods:

This is a cohort study of consecutive patients (n = 361 enrolled between 1988-1997) with idiopathic dilated cardiomyopathy. LVRR was assessed via echocardiography at baseline and at the 24-month mid-term follow-up. LVRR was defined as: 1) an LV ejection fraction (LVEF) increase >10% or an LVEF ≥50% in patients with an LVEF 45-49% at enrollment, and 2) a ≥10% decrease in LV end-diastolic diameter (LViDd) or an indexed LViDd of ≤33/m2 at 24 months. Patients without complete data (n = 84, 34%) and those having died or undergoing transplant prior to mid-term follow-up (n = 34, 9%) were excluded from the final cohort study. Baseline correlates of LVRR were evaluated with logistic regression. Two Cox proportional hazards models were generated for assessing survival free of transplant. One model included baseline data only, and the second included baseline variables along with select data measured at 24 months. The models were compared via receiver operating characteristic curves.

Results:

At baseline, mean patient age was 43 ± 13 years, 18% had New York Heart Association (NYHA) class III/IV heart failure, the mean LVEF was 31 ± 10% (50% had LVEF ≤30%), and HF duration was a mean of 13 ± 25 months. Beta-blockers and angiotensin inhibitors were used in 85% and 91%, respectively. Of the 242 patients with echocardiographic data at 24 months, LVRR was noted in 89 (37%). The odds of having LVRR were higher in those without a left bundle branch block (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.3-4.9) and those with higher systolic blood pressures (OR, 1.2; 95% CI, 1.01-1.53, per 10 mm Hg) at baseline. After a mean 123 ± 61 months of follow-up, there were 155 (64%) survivors and 87 (36%) deaths/transplants. Subjects with LVRR at 24 months had better survival free of transplant compared with those without LVRR (78% vs. 57%, respectively, at 12 years, p < 0.001). Baseline multivariable correlates of death/transplant included male sex, longer durations of heart failure, NYHA class III/IV, lower LVEF, moderate to severe mitral regurgitation, and absence of beta-blocker therapy. The presence of advanced heart failure symptoms, LVRR, and moderate-severe mitral regurgitation at 24 months of follow-up added to the prognostication of the above baseline variables, offering better outcome discrimination (area under the curve [AUC] 0.80) than the model employing baseline variables alone (AUC 0.70, p = 0.004 for AUC comparison).

Conclusions:

LVRR occurred in approximately one-third of patients studied with dilated cardiomyopathy, and was associated with fewer long-term events.

Perspective:

This is the first large population study of LVRR in patients with nonischemic dilated cardiomyopathy. Importantly, this study focuses on those surviving 24 months free of transplant, thereby selecting out a lower risk group of patients with a very respectable 12-year survival. In these select patients, absence of LVRR portended worse outcome. The absence of LVRR may be a marker of ‘treatment failure,’ and may help to identify those ‘lower risk’ individuals with heart failure who are at higher risk for adverse events in the long-term. An important limitation of this study is the era of cohort enrollment. It is likely that few patients received aldosterone antagonists or defibrillator/biventricular pacemaker therapies. Many would argue that magnetic resonance imaging would now be the ‘gold standard’ for assessment of LV remodeling, offering better accuracy and less inter- and intra-observer measurement variability. Finally, 34% of patients in the original cohort were excluded due to incomplete data, which may compromise some of the validity of the results.

Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Implantable Devices, SCD/Ventricular Arrhythmias, Acute Heart Failure, Echocardiography/Ultrasound

Keywords: Survivors, Prevalence, Defibrillators, Follow-Up Studies, Heart Failure, Ventricular Remodeling, Pacemaker, Artificial, New York, Cardiomyopathy, Dilated, Echocardiography


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