Relationship between leukocyte and subtype counts, low-grade inflammation and slow coronary flow phenomenon in patients with angiographically normal coronary arteries

Abstract

Background: Slow coronary flow (SCF) is an angiographic finding characterized by delayed opacification of epicardial coronary arteries in the absence of obstructive coronary disease. Leukocytes and low-grade inflammation play a major role in atherosclerotic vascular processes and may be important in other coronary pathologies. Therefore, we aimed to investigate whether there is a positive correlation between leukocyte counts, high-sensitive C-reactive protein (hsCRP) and SCF determined by frame rates. Methods: Seventy-seven individuals who underwent coronary angiography with suspected CAD, and had angiographically normal coronary arteries (NCA) of varying coronary flow rates were enrolled. From the original 77 study participants, forty-seven patients with NCA and SCF in all three coronary vessels and 30 sex- and age-matched control participants with NCA but without SCF were investigated. The quantification of the coronary flow was assessed by use of the TIMI frame count method (TFC) in all coronary arteries. The normal flow was defined as TFC < 28 frames and slow flow as TFC ? 28 frames. Results: HsCRP was significantly positively correlated with mean TFC (r = 0.522, p < 0.001). In addition, leukocytes, neutrophils and monocytes were significantly positively related to mean TFC (r = 0.353, p = 0.002; r = 0.298, p = 0.009 and r = 0.511, p < 0.001, respectively). In multivariate analyses, only hsCRP (?: 0.324, p = 0.003) and monocyte count (?: 0.354, p = 0.003) were related to SCF as determined by TFC. Conclusion: Our results showed that circulating monocytes and low-grade inflammation are related to SCF. Although we cannot make conclusive assumptions about the underlying pathologic process of SCF, we believe that these findings may be pivotal for further studies which seek to ascertain the specific roles of monocytes and hsCRP on SCF phenomenon in coronary vasculature.