Perioperative brain natriuretic peptide in off-pump coronary artery bypass

During the last decade brain natriuretic peptide (BNP) has been recognized as a useful marker for acute and chronic left ventricular dysfunction. The present study was designed to evaluate the clinical relevance of BNP before and after off-pump coronary artery bypass (OPCAB).

One hundred and twelve patients undergoing primary OPCAB were divided into two groups by preoperative BNP levels (group A, BNP < or = 100 pg/ml and group B, BNP > 100 pg/ml). Levels of BNP and MB isoenzyme of creatine kinase (CK-MB) were measured preoperatively, 6 hours and 1 day post-operatively. Echocardiographic and clinical data were collected.

Patients in group A had smaller perioperative left ventricular end-diastolic dimensions (LVEDD) and greater left ventricular ejection fractions (LVEF) compared to group B (P < 0.05). Levels of BNP and CKMB increased postoperatively in both groups (P < 0.01). However, there was no relationship between postoperative BNP and CKMB at any time point. Logistic regression analyses showed that a preoperative BNP level > 100 pg/ml was an independent risk factor for ventilation > 24 hours (odds ratio, OR = 13.33; 95% CI: 1.42-125.03) and ICU stay > 72 hours (OR = 3.01; 95% CI: 1.09-8.33).

The baseline BNP level correlated with preoperative ventricular function and longer durations of ventilation and hospital stay after OPCAB. BNP increased early after operation. However, postoperative BNP did not correlate with myocardial injury or clinical results after OPCAB.