Poor awareness of chronic kidney disease in patients with acute coronary syndrome--challenge for cardiologists and nephrologists

Abstract

Sir, In the last issue of Nephrology, Dialysis and Transplantation, we read with great interest a review by Charles A. Herzog regarding kidney disease in cardiology [1]. In this article, the author highlighted three clinically relevant topics concerning acute kidney injury in patients with ischaemic heart disease, use of statins in chronic kidney disease (CKD) and ischaemic heart disease in patients with end-stage renal disease. In our opinion, this review omitted an important area, namely the poor awareness of CKD in patients with acute coronary syndrome (ACS) and cardiologists taking care of them. However, this very important topic is not often present in the literature. Epidemiologicalstudiesofrecentyearsfocusedontheincreased cardiovascular morbidity and mortality in patients with chronic kidney disease [2]. It was found that CKD is not only an important cause of arterial hypertension, left ventricle hyperthrophy and anaemia but also a risk factor for the development of accelerated arteriosclerosis and atheromatosis of both coronary and peripheral arteries (cardio-renal syndrome) [3]. Reddan et al. documented that almost 40% of patients with ACS suffer from at least stage 3 of CKD [4]. Therefore, we have performed a study that aimed to evaluate the awareness of CKD and effectiveness of the referral process to nephrologists in patients with ACS. The survey involved 150 patients (78 women and 72 men) with ACS referred to the cardiology unit [Table 1]. Patients were treated noninvasively or underwent urgent primary coronary intervention when TIMI Risk Score was equal or over 5 points. For each patient, detailed anamnesis concerning cardiovascular and kidney diseases and nephrological care was obtained. Based on estimated eGFR (MDRD formula) and urine analysis, CKD was diagnosed in 137 (91.3%) patients with ACS. eGFR <60 ml/min/ 1.73 m 2 was found in 29.3%, while proteinuria over 1 g/l in 9.3% of all patients with ACS. None of those patients was treatedbyanephrologistbeforetheoccurrenceofACS.The most frequently previously undiagnosed CKD was diabetic nephropathy (53%). After discharge from the cardiology unit, patients with diagnosed stages 3 and 4 of CKD or proteinuria over 1 g/l were referred to nephrologists. One-third of patients (n = 16) refused immediately. Finally, documented nephrological care during the 1-year follow-up period was undertaken only in 16 out of 48 initially referred patients (33.3%) (excluding 4 patients who died). Our results clearly indicate the poor awareness of CKD in patients with ACS. What is especially sad, is that even