Original article Renal insufficiency increases mortality in acute coronary syndromes regardless of TIMI risk score

Abstract

Background:
Non ST-segment elevation acute coronary syndromes (NSTE ACS) are the most frequent cause of admission to intensive care units. Early risk assessment and implementation of optimal treatment are of special importance in these patients. Previous studies have demonstrated that renal insufficiency is an independent risk factor in patients with cardiovascular disease.
Aim:
To assess the effects of renal function on the course of treatment and prognosis in patients with NSTE ACS admitted to hospitals without on-site invasive facilities but with a possibility of immediate transfer to a reference centre with a catheterisation laboratory.
Methods:
Twenty-nine community hospitals without on-site invasive facilities participated in the Krakow Registry of Acute Coronary Syndromes – a prospective, multicentre, web-based, observational registry. Renal insufficiency (RI) was defined as creatinine clearance (CrCl) <60 ml/min.
Results:
NSTE ACS was diagnosed in 1396 patients. Renal insufficiency was diagnosed in 34% of all patients. Only 17% of them had been diagnosed with RI prior to admission. Transfer for invasive treatment was undertaken in 10% of RI patients as compared to 16% of patients with CrCl >60 ml/min (NS). In-hospital mortality among patients remaining on conservative treatment in community hospitals was significantly higher among RI patients (4.0 vs. 0.6%; p <0.001). Thienopyridines were less frequently used in RI patients (46 vs. 54%; p <0.05). In-hospital mortality among RI patients remaining in community hospitals and treated conservatively was higher than among non-RI patients in each TIMI risk score group: 7.3 vs. 2.4% (p <0.05) in the high risk group, 4.1 vs. 1.4% (NS) in the moderate and 3.6 vs. 0% (p <0.001) in the low risk group. Multivariate logistic regression analysis identified reduced creatinine clearance and a history of heart failure as independent factors influencing mortality.
Conclusions:
Renal insufficiency was present in one-third of NSTE ACS patients. Patients with renal insufficiency had worse clinical risk profile and received less aggressive treatment. Patients with NSTE ACS and renal insufficiency treated conservatively had higher in-hospital mortality. Renal insufficiency modifies mortality irrespective of the TIMI risk score. Creatinine clearance should be considered in modification of the TIMI risk score scale.