ABC | Volume 114, Nº3, March 2020

Original Article Determination of Myocardial Scar Tissue in Coronary Slow Flow Phenomenon and The Relationship Between Amount of Scar Tissue and Nt-ProBNP Mustafa Candemir, 1, 2 A sife Şahinarslan, 2 Merve Yazol, 3 Yusuf Ali Öner, 4 Bülent Boyacı 2 Yozgat City Hospital - Department of Cardiology, 1 Yozgat - Turkey Gazi University - Faculty of Medicine - Department of Cardiology, 2 Ankara - Turkey Şanlıurfa Education and Research Hospital, Department of Radiology, 3 Şanlıurfa - Turkey Gazi University - Faculty of Medicine - Department of Radiology, 4 Ankara - Turkey Mailing Address: Mailing Address • Yozgat City Hospital, Department of Cardiology, Yozgat, 66100, Turkey E- mail: mstfcndmr@hotmail.com Manuscript received August 15, 2018, revised manuscript April 27, 2019, accepted June 05, 2019 Abstract Background: Pathophysiology and prognosis are not clearly determined in patients with the coronary slow flow phenomenon (CSFP). These patients present with various clinical conditions ranging from being asymptomatic to being admitted with sudden cardiac death. Objectives: We aimed at assessing the findings of late gadolinium enhancement (LGE) in cardiac magnetic resonance imaging (CMR) as an indicator of myocardial fibrosis. We also aimed at determining the relationship between the presence of myocardial fibrosis and NT-proBNP levels in patients with CSFP in the left anterior descending coronary artery (LAD). Methods: A total of 35 patients were enrolled within an age range of 31-75. The study patients (n=19) had normal epicardial coronary arteries at angiography, but they presented with CSFP in the LAD. The control group patients (n=16) had normal epicardial coronary arteries and TIMI scores at normal levels in angiography. In both groups, the patients were examined with CMR for the presence of myocardial fibrosis. In addition, plasma NT-proBNP levels were measured. A p-value < 0.05 was considered significant. Results: The rate of myocardial fibrosis was significantly higher in CMR in the patients with CSFP (p=0.018). A variable amount of myocardial scar tissue was detected at the left ventricular apex in 7 patients and at the inferior and inferolateral regions in 3 patients. There was no difference in the level of NT-proBNP in patients with CSFP. However, the NT-proBNP levels were higher in patients with CSFP, who had scar tissue in CMR (p=0.022). Conclusions: In conclusion, LGE in CMR showed that ischemic myocardial scarring may exist in patients with CSFP. These results indicate that CSFP may not always be innocent. (Arq Bras Cardiol. 2020; 114(3):540-551) Keywords: Heart Failure; Fractional Flow Reserve, Myocardial; Cicatrix, Hypertrophic; Prognosis; Natriuretic-Peptide, C-Type; Endomyocardial Fibrosis, Magnetic Resonance Spectroscopy. Introduction There is limited information in the literature regarding the prognosis of slow coronary flow phenomenon (CSFP). The preexisting data indicates that slow flow-related myocardial ischemia may cause angina and the prognosis is worse in these patients. 1 Acute myocardial infarction, 2 sudden cardiac death and malignant ventricular arrhythmia were also reported to be associated with CSFP. 3 The occurrence of recurrent episodes of chest pain or chest pain developing at rest, as well as high rates of emergency admissions, and hospitalizations are reported. 4,5 Thus, this phenomenon is not as innocent as it appears to be, bearing a potential to cause serious deterioration in the quality of life. It is not clearly known today whether organic injuries exist in these patients, due to the lack of further investigation and findings. The level of N-terminal proB-type natriuretic peptide (NT- proBNP) has been shown to increase after exercise in patients with slow coronary artery flow. 6 There is a correlation between ischemia or infarct size on magnetic resonance imaging (MRI) and this correlation can be observed in the NT-proBNP levels in patients with acute coronary syndrome as well. 7 As a result of the advances in cardiac magnetic resonance imaging (CMR), microvascular ischemia and cardiac fibrosis can be demonstrated using this technique. 8,9 The relation between the extent of fibrosis and NT-proBNP levels in these patients has been revealed by several MRI studies performed in patients with acute coronary syndrome. 10,11 However, there are no studies in the literature evaluating patients with CSFP for the DOI: https://doi.org/10.36660/abc.2018149 540