Contrast-induced nephropathy prediction following ST-elevation myocardial infarction: Missing links.

Dear Editor, The study by Ceylan and Yildirim outlining H2FPEF score as independent predictor of contrast-induced nephropathy (CIN) in ST-elevation myocardial infarction (STEMI) patients undergoing percutaneous coronary intervention (PCI), emerges as an exemplary research work.1 Nonetheless, considering the relevance of the research subject, additional insights into the topic would certainly interest the Journal readership. The authors retrospectively analyze the data of 355 patients, wherein one misses a comparative account of the serum albumin (SA) levels in the cohort developing CIN (n = 63) as opposed to those without CIN (n = 292).1 The importance of the former is heralded by the Wiedermann et al meta-analysis suggesting a causal association between hypoalbuminemia and acute kidney injury (AKI), emanating from a total of 43 studies and 68,262 subjects.2 Notably so, the meta-analysis included 8 studies with 4,344 patients combined from either cardiac surgical or PCI settings.2 More importantly, Murat et al retrospectively delineate significantly lower SA in their acute coronary syndrome (ACS) patients with contrast-induced AKI, or CI-AKI (n = 107) compared to those with normal renal function following PCI (n = 783) (3.52 ± 0.40 v/s 3.94 ± 0.39 mg/ dL, P < 0.001).3 Subsequent to a multivariate analysis, the group highlights SA as an independent CI-AKI predictor (OR; 95% CI: 0.177; 0.080-0.392, P < 0.001) in a research scenario demonstrating peculiar similarities to the Ceylan and Yildirim study.1,3 Ahead of the well-known pro-inflammatory links of both hypoalbuminemia and AKI, Wei et al elucidate a pivotal role of nutritional status in determining the eventual risk to contrast-induced renal injury in an elderly subset undergoing PCI.2-5 Indeed, the dual relationship of SA with malnutrition and inflammation cannot be overemphasized, particularly in advanced age.3,5 Moreover, whilst the inclusion of SA could have augmented the contextual research lucidity, the optimal CIN-predictive cut-off of the H2FPEF score might also require further consolidation given the recent literature in the subject (H2FPEF cut-off of 2.5 predicting CIN in ACS patients with 79.8% and 64.1% sensitivity-specificity in Ozbeyaz et al study vis-à-vis a CIN-predictive cut-off of 1.5 emanating from the Ceylan and Yildirim study and demonstrating a sensitivity-specificity of 64.0% and 72.1% in an exclusive STEMI cohort).1,6