Abstract 2083: Improvement in Coronary Flow Reserve is Associated With Late Recovery of Left Ventricular Function After Carvedilol Therapy in Patients with Idiopathic Dilated Cardiomyopathy
Background: Beta-blocker therapy reverses left ventricular (LV) remodeling in patients with idiopathic dilated cardiomyopathy (IDC). Improvement in coronary circulation by beta-blocker could play a role in theses circumstances. This study investigated the relationship between change in coronary flow reserve (CFR), as a marker of coronary circulation, and subsequent improvement in LV ejection fraction (LVEF) at follow-up during carvedilol therapy in IDC patients.
Methods: We studied 20 patients with IDC (mean age 56 ± 15 years, NYHA I–II) who were scheduled to receive carvedilol therapy. All patients were stabilized using an angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker and diuretic treatment. Transthoracic Doppler echocardiography with intravenous infusion of adenosine triphosphate was used to assess CFR in the left anterior descending artery at baseline and after 1 month of treatment with carvedilol. A follow-up echocardiographic assessment of LVEF was done at 12 ± 6 months of treatment. The patients were classified by the degree of improvement in LVEF in the follow-up study, as Group A (LVEF change ≥10%) and Group B (LVEF change <10%).
Results: Although there was no significant difference in CFR between the 2 groups at baseline (Group A vs. Group B, 2.4 ± 1.0 vs. 2.2 ± 0.8; P=NS), CFR was significantly higher in Group A than in Group B at 1 month of therapy (3.7 ± 0.5 vs. 2.5 ± 0.9; P<0.01). The magnitude of CFR change after 1 month of therapy was significantly greater in Group A than in Group B (1.3 ± 0.6 vs. 0.4 ± 0.5; P<0.01). Logistic regression analysis revealed that CFR change predicted a significant improvement in LVEF at follow-up (P<0.05). Furthermore, a significant correlation was found between the change in CFR after 1 month and that in LVEF on follow-up (r=0.65, P<0.01).
Conclusions: This study demonstrated that early change in CFR is associated with subsequent improvement in LVEF, suggesting the potential predictive value of coronary circulation for subsequent LV reverse remodeling after beta-blocker therapy in patients with IDC.