Natriuretic peptides in addition to Zwolle score to enhance safe and early discharge after acute myocardial infarction: A prospective observational cohort study

BackgroundThe Zwolle score is recommended to identify low-risk patients eligible for early hospital discharge after ST-elevation myocardial infarction (STEMI), but since only one third of STEMI has low Zwolle score, hospital discharge is frequently delayed. B-type natriuretic peptide (BNP) also provides prognostic information after STEMI. The aim of the study was to test the hypothesis that patients with high Zwolle score associated with low BNP share similar outcomes than those with low Zwolle score.Methods and resultsThe study population consisted of 1032 consecutive STEMI patients in whom BNP was measured 24 h after chest pain onset. The area under the curve of Zwolle score and plasma BNP for 30-day mortality were 0.82 and 0.87, p = 0.39. A BNP threshold of 200 pg/ml had sensitivity of 100% and specificity of 34% for predicting 30-day mortality. Patients with high Zwolle score and BNP ≤ 200 pg/ml (n = 183) had similar mortality and hospital stay to those with low Zwolle score (0% vs. 0.5% and 5 vs. 5 days, both p = 1.0). By contrast, patients with high Zwolle score and BNP > 200 pg/ml had the highest mortality (6.7%) and the longest hospital stay (6 days), both p < 0.01.ConclusionSTEMI patients with high Zwolle score but low BNP share similar outcomes with those with low Zwolle score and should be eligible for early discharge. Hence, using the rule of “low-Zwolle or low-BNP” might increase the number of STEMI patients that might be eligible for early discharge.