Abstract 3575: Patients With High Baseline Levels of B-Type Natriuretic Peptide are Less Likely to Experience Significant Left Ventricular Reverse Remodeling With Cardiac Resynchronization Therapy in the Multicenter InSync Randomized Clinical Evaluation (MIRACLE) Trial
Background: Cardiac resynchronization therapy (CRT) can improve cardiac function and clinical status in heart failure (HF) patients with ventricular dyssynchrony; however, there are a substantial number of patients who do not seem to benefit from CRT. Thus, accurate tests to help predict responders and non-responders are a high priority. While there is no clearcut definition of what constitutes a significant response to CRT, reduction in left ventricular end systolic volume (LVESV) has been shown to be associated with improved outcome. We investigated whether baseline plasma B-type natriuretic peptide (BNP) would predict subsequent reverse remodeling in patients treated with CRT in the Multicenter InSync Randomized Clinical Evaluation (MIRACLE) trial.
Methods: Entry criteria included NYHA class III-IV, LV ejection fraction ≤35%, end diastolic diameter ≥55 mm, and QRS duration ≥130 ms. We analyzed patients randomized to the CRT group with paired echo and BNP values (baseline- 6 months). Baseline BNP values were divided into quintiles. Reverse remodeling was defined
as ≥15% reduction in LVESV and
≥15% reduction in LVESV and/or ≥20% increase in LV ejection fraction. *p<0.05 with chi-square test.
Results: Limits between BNP quintiles were 112, 272, 674, and 1451 pg/mL (n=144). With definition
the % of responders in the BNP quintiles were 71, 73, 50, 42, and 24%*. Further %s based on etiology: ischemic HF etiology (n=71): 60, 63, 9, 25, 22%*; non-ischemic etiology (n=73): 75, 90, 85, 60, 27%*. With definition
the % of responders in the BNP quintiles were 82, 77, 58, 48, and 48%*, with ischemic HF etiology 70, 69, 27, 31, 44%, p=0.08, and with non-ischemic etiology 88, 90, 85, 67, 55%, p=0.13.
Conclusion: In the MIRACLE trial, lower baseline plasma BNP especially with a non-ischemic etiology appears more likely to be associated with significant LV reverse remodelling with CRT than higher BNP activation or an ischemic etiology. While BNP cannot guarantee or rule out a favorable response, its use may provide some guidance regarding the likelihood of significant reverse remodelling.