The role of pre-existing renal dysfunction on in-hospital morbidity and mortality in patients with acute coronary syndrome

Abstract

Introduction The baseline renal function is an important predictor for the prognosis of patients with acute coronary syndrome (ACS).

The aim of our study was to analyse the impact of pre-existing renal failure (RF) and the risk profile of patients with ACS on the development of in-hospital morbidity and mortality.

Materials and methods This was a single-center cross-sectional cohort study on 2702 patients with ACS. The main exclusion criterion was pre-existing left ventricular (LV) dysfunction. Demographical and clinical characteristics, biochemical parameters, the anatomical distribution of coronary artery disease, and the final outcomes were analysed according to presence of RF at the moment of the index event. The estimated glomerular filtration rate (eGFR) was calculated by the Modification of Diet in Renal Disease Study Group Equation (MDRD), where patients with eGFR<60 ml/min/1.73 m2 had moderate to severe renal dysfunction.

Results 777 (22.3%) out of 2702 patients had eGFR <60 ml/min at the moment of the index event. These patients were predominantly female, 34.1% (333) vs.17.7% (444), p=0.0004,OR 1.921(95%CI 1.701-2.168);older (70.0±9.7vs.60.5±10.7;p <0.000). They had significantly higher values of cardiac troponin (p=0.007), stress glycemia (p=0.000019), glycated hemoglobin (p=0.000012), and WBC (p=0.00001), meaning the extent of myocardial injury was bigger, with a more activated neuro-hormonal and inflammatory response in the conditions of the notably widespread anatomical distribution of CAD. However, patients with significantly reduced eGFR were less likely to be offered coronary angiography and PCI treatment, OR 0.524 (95%CI 0.434–0.632),p <0.000. As expected, anemia predominated in these patients (RBC 4.88±0.75 vs 4.53±0.58, p=0.000001; OR 1.27 (95% CI 1.09-1.48), and Hgb 143.81±16.69 vs 132.03±21.34, p=0.00001). They had a significantly lower level of sodium (p=0.008) and a higher level of potassium (p=0.00003). Interestingly, patients with eGFR <60 ml/min had lower lipoprotein levels. In-hospital mortality rate was 4.2%, however, significantly higher in reduced eGFR group (12% vs 1.9%, OR 6.9 (95% CI 4.9–9.8), p <0.00004). These patients were more likely to develop acute kidney injury [25.7% vs. 1.3%, OR 1.6 (95% CI 1.3-1.9, p = 0.000021)], pulmonary oedema [8% vs. 1.8%, OR 1.12 (95% CI 1.02-1.23, p = 0.000021), and cardiogenic shock [19.5% vs. 2.6%, OR 1.22 (95% CI 1.2-1.4), p = 0.00023]. Independent variables associated with RF were: advanced age, female gender, extracardiac ASCVD, previous CVI, previous RAAS treatment, stress glycemia, triglyceride, cholesterol, LDL-C, Hgb, WBC, and potassium level.

Conclusion Patients with reduced eGFR (<60 ml/min) have a very specific risk profile, as identified in our study, and reduced eGFR is a major contributor to the prognosis of ACS, highly responsible for in-hospital morbidity and mortality.