ABC | Volume 115, Nº1, July 2020

Review Article Leite et al. Acute cardiorenal syndrome Arq Bras Cardiol. 2020; 115(1):127-133 Intermittent ACRS reflects a reversible reduction in GFR and seems less harmful than persistent ACRS. Paradoxically, in cases of ACRS on admission, the decrease in creatinine during hospitalization can be associated with adverse outcomes. 28,53,62 Considering renal congestion as the major pathophysiological mechanism of ACRS, diuretics are expected to have a beneficial effect on prognosis. A post hoc analysis of the DOSE trial 63 has shown that renal function improvement when associated with inadequate decongestive strategies had a worse prognosis. Other studies have shown that, with diuretic therapy and hemoconcentration, worsening renal function has a lower impact on prognosis than in patients with persistent congestion and no hemoconcentration. 28,64 Those findings are partially due to confounding factors in serum creatinine assessment. In the context of measures of decongestion, the increase in serum creatinine can result from other mechanisms regardless of GFR reduction, such as hemoconcentration that reduces the distribution of creatinine. That renal change is harmless and transient, and named pseudo-AKI. The concept of pseudo‑AKI can explain why biomarkers of tubular lesion were poor predictors of ACRS, considering that previous studies have made no distinction between AKI and pseudo‑AKI. 62,65 During aggressive diuretic therapy, serum creatinine increased in 22% of the patients with DHF without increase in biomarkers, suggesting a potentially high proportion of pseudo-AKI. 65 It is not easy to determine whether the therapy is effective and pseudo-AKI can induce inadequate discontinuation of treatment. It is worth assessing the clinical parameters of perfusion, urine output, body weight loss and hemoconcentration. In addition, biomarkers seem to be good to guide therapy. 66 Measuring cardiac output and other hemodynamic parameters can help ensure an adequate and directed diuretic therapy, 67 in addition to enabling better understanding of ACRS. Conclusions The different references of baseline serum creatinine limit the capacity of accurate comparisons between studies and interfere with the estimates of ACRS diagnosis, overestimating or underestimating it. This study suggests that the ACRS criteria should be revised to include the diagnosis of ACRS on hospital admission. Reference creatinine should reflect baseline renal function before AKI begins. Author contributions Conception and design of the research: Leite AM, Gomes BFO, Albuquerque DC, Spineti PPM, Martins WA; Acquisition of data and Writing of the manuscript: Leite AM; Analysis and interpretation of the data: Leite AM, Gomes BFO, Marques AC, Petriz JLF, Albuquerque DC, Spineti PPM, Villacorta H, Martins WA; Critical revision of the manuscript for intellectual content: Leite AM, Gomes BFO, Marques AC, Petriz JLF, Albuquerque DC, Spineti PPM, Jorge AJL, Villacorta H, Martins WA. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This article is part of the thesis of master submitted by Andréa de Melo Leite, fromUniversidade Federal Fluminense. 1. Rohde LEP, Montera, MW, Bocchi EA, Clausell NO, Albuquerque DC, Rassi S, Colafranceschi AS, et al. Diretriz Brasileira de Insuficiência Cardíaca Crônica e Aguda. 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