Coronary slow flow phenomenon and microalbuminuria: Is there any relationship?

OBJECTIVE
The pathophysiology of coronary slow flow phenomenon (CSFP) is poorly understood. Evidence suggesting endothelial dysfunction in patients with slow coronary flow (SCF) led to this evaluation of a possible correlation between microalbuminuria (MAU), as an indicator of endothelial dysfunction, and CSFP in order to investigate a mutual pathophysiology.

METHODS
In this case-control study, 15786 patients who presented between September 2016 and April 2018 were screened. All patients with CSFP had chest pain and coronary angiography was indicated due to a positive noninvasive test. All cases had a Thrombosis in Myocardial Infarction (TIMI) flow grade of 2 or a corrected TIMI frame count of >27 without any evidence of obstructive coronary artery disease. The patients used as controls had completely normal coronary angiograms. Fasting mid-stream urine samples were analyzed using an immunoturbidimetric assay to determine the albumin-creatinine ratio (ACR) as a surrogate of microalbuminuria (MAU) (ACR: 30–300 mg/g). The prevalence of MAU in the case and control groups was analyzed.

RESULTS
A total of 154 individuals with a normal coronary angiogram and 46 patients with SCF were enrolled in the study. The prevalence of MAU was greater in patients with SCF than in the control group (8.7% vs 1.9%, respectively; p=0.048). Even after adjustment for major risk factors, the association between MAU and CSPF remained significant.

CONCLUSION
The results of this study indicated that there was a relationship between MAU and CSFP and confirmed that endothelial dysfunction is a contributing factor to CSFP. These findings are of utmost importance due to the prognostic value of MAU for both all-cause and cardiovascular mortality rates.