Acid–base imbalance in uncomplicated ST-elevation myocardial infarction: the clinical role of tissue acidosis

摘要

Little information is available on acid–base imbalance in uncomplicated ST-elevation myocardial infarction (STEMI) submitted to primary percutaneous intervention (PCI). We therefore assessed acid–base imbalance in 257 consecutive uncomplicated STEMI patients submitted to PCI to determine whether its evaluation could help in identifying patients at higher risk for in-hospital complications (acute pulmonary edema and dysrhythmias). A basic metabolic profile was performed at hospital admission, that is before PCI. After PCI, we measured: creatinine, uric acid and NT-pro BNP and serum electrolytes. Peak troponin I was also considered. Acidemia was present in 11 patients (4.2%), HCO₃ < 22 in 62 (24.1%). Base excess 12 in 13 (5.1%), Cl/Na < 0.79 in 93 patients (38.5%). Patients with a Cl/Na < 0.79 had a lower LVEF (p = 0.042) and higher values of NT-pro-BNP (p = 0.019) and of latency (p = 0.029) together with a higher length of stay (p = 0.017) and a higher incidence of in-hospital complications (p = 0.017). At backward stepwise regression analysis, the following variables resulted independent predictors of in-hospital complications: base excess OR 1.47 (95% CI 1.04–2.10) p = 0.031; Cl/Na ratio O.R. 1.85 (95% CI 1.05–3.27) p = 0.035. In STEMI patients submitted to mechanical revascularization the evaluation of acid–base status and, in particular the detection of even mild degrees of acidosis may help in risk stratification for in-hospital complications. A Cl/Na < 0.79 ratio and a base excess are independent predictors for in-hospital complications.