The Impact of Kidney Function on the Slow-Flow/No-Reflow Phenomenon in Patients Treated with Primary Percutaneous Coronary Intervention: Registry Analysis

Objective. The objective of this study is to analyze the impact of declining kidney function on the occurrence of the slow-flow/no-reflow phenomenon in patients with ST-elevation myocardial infarction (STEMI) treated with primary PCI (pPCI), as well as the analysis of the prognostic impact of the slow-flow/no-reflow phenomenon on short- and long-term mortality in these patients. Methods. We analyzed 3,115 consecutive patients. A value of the glomerular filtration rate (eGFR) at the time of admission of eGFR <90 ml/min/m2 was considered a low baseline eGFR. The follow-up period was 8 years. Results. The slow-flow/no-reflow phenomenon through the IRA was registered in 146 (4.7%) patients. Estimated GFR of <90 ml/min/m2 was an independent predictor for the occurrence of the slow-flow/no-reflow phenomenon (OR 2.91, 95% CI 1.25–3.95, $p$ < 0.001), and the risk for the occurrence of the slow-flow/no-reflow phenomenon increased with the decline of the kidney function: eGFR 60–89 ml/min/m2: OR 1.94 (95% CI 1.22–3.07, $p$ = 0.005), eGFR 45–59 ml/min/m2: OR 2.55 (95% CI 1.55–4.94, $p$ < 0.001), eGFR 30–44 ml/min/m2: OR 2.77 (95% CI 1.43–5.25, $p$ < 0.001), eGFR 15–29 ml/min/m2: OR 5.84 (95% CI 2.84–8.01, $p$ < 0.001). The slow-flow/no-reflow phenomenon was a strong independent predictor of short- and long-term all-cause mortality: 30-day mortality (HR 2.62, 95% CI 1.78–3.57, $p$ < 0.001) and 8-year mortality (HR 2.09, 95% CI 1.49–2.09, $p$ < 0.001). Conclusion. Reduced baseline kidney function was an independent predictor for the occurrence of the slow-flow/no-reflow phenomenon, and its prognostic impact started with the mildest decrease in eGFR (below 90 ml/min/m2) and increased with its further decline. The slow-flow/no-reflow phenomenon was a strong independent predictor of mortality in the short- and long-term follow-up of the analyzed patients.