Abstract 14386: Determinants of Chronic Phase Plasma Bnp Levels in Patients after Extremely Large Acute Myocardial Infarction: Does Cardiac Rehabilitation Exercise Training Adversely Affect?

Abstract

[Background] The impact of exercise training in cardiac rehabilitation (CR) on plasma B-type natriuretic peptide (BNP) levels in chronic phase after extremely large acute myocardial infarction (AMI) is unknown. The purpose of the present study was to determine whether excessive intensity or amount of exercise training in CR program hampers the favorable decrease in plasma BNP levels in patients after extremely large AMI. [Methods] We studied 92 patients with extremely large first AMI (defined as peak CK >= 5500mg/dl) among 835 AMI patients who participated in our CR program and underwent measurements for BNP and exercise capacity at the beginning and the end of the 3-month program. Patients were categorized into two groups according to plasma BNP levels >= or <100pg/ml at 3 months: High BNP (n=58) and Low BNP groups (n=34). [Results] In the acute phase, peak CK levels were very high in both groups, but did not differ between the groups (High BNP group 7804U/L vs Low BNP group 7274, NS). Plasma BNP levels significantly fell in both groups at 3 months (High group 381 to 263pg/mL, Low group 207 to 55pg/mL, both p<0.01), but the reduction was significantly smaller in High BNP than Low BNP group (12.6% vs 64.0%, p<0.01). High BNP group showed significantly, lower left ventricular ejection fraction (LVEF, 35% vs 40%, p<0.01), lower glomerular filtration rate (eGFR, 59 vs 68mL/min/1.73m2, p<0.05), and lower hemoglobin levels (12.6 vs 13.6g/dL, p<0.05) compared with Low BNP group. Regarding measures of intensity and amount of exercise training, prescribed training heart rate was significantly lower in High BNP group (99.2 vs 108.3bpm, p<0.05), and there were no differences in the numbers of exercise session attendance or the percentage improvement in exercise capacity (peak oxygen uptake, peak work rate). [Conclusions] In patients with extremely large AMI,LVEF, renal function, and anemia were the determinants of plasma BNP in chronic phase. Active participation in CR does not adversely affect chronic phase BNP in these patients.