Background: Phenomenon of Coronary Slow Flow (CSF) is a rare clinical entity leading to angina, ischemic electrocardiographic changes and abnormal cardiac scintigraphy while having normal appearance of coronary arteries.
Objective: The study was aimed to explore the clinical and angiographic characteristics of this peculiar condition among our Sri Lankan patients. Methodology: A retrospective cross sectional study was conducted at teaching hospital Kandy, Sri Lanka. All consecutive patients scheduled for coronary angiography between 2014 and 2016 were included. CSF was diagnosed based on the Thrombolysis In Myocardial Infarction (TIMI) frame count (TFC) of coronary flow. Coronary arteries without plaque burden and a TFC > 27 of flow rate was defined as having CSF phenomenon. Angiograms were reviewed by two examiners individually. The clinical details were obtained by interviewer administered questionnaire. A comparison was made with age and gender matched control group, who had normal coronaries.
Results: The mean age of the sample was 52.18 ± 8.99 years and 65.50% (n=25) were males. Out of the sample, 15.00% (n=6) had diabetes, 32.50% (n=13) had hypertension and 32.50% (n=13) had dyslipidaemia as risk factors. Out of that 67.50% (n=27) had acute coronary syndromes and 50.00% (n=20) presented with recurrent atypical chest pains. In the sample 50.00% (n=50) had positive, 37.50% (n=15) had negative and 12.50% (n=5) had inconclusive stress test by Bruce protocol. Out of the sample, 57.50% (n=23) had ejection fraction ≥55% and 62.50% (n=25) hadn’t have wall motion abnormalities Prevalence of CSF in triple vessels was 35.00% (n=14). There were 45.00% (n=18) had slow flow involving two vessels being Left Anterior Descending (LAD) & Right Coronary Artery was the commonest combination. Single vessel involvement was 20.00% (n=8) and LAD was the commonest artery involved. There was no statistical significance of age (p=0.74), gender (p=0.52), prevalence of hypertension (p=0.91), diabetes mellitus (p=0.83), dyslipidaemia (p=0.24) among patients with CSF compared to controls.
Conclusion: CSF phenomenon is an infrequent finding in patients with angina but commonly precipitates to recurrent episodes of chest pains. These patients often have positive stress tests and occasional to have wall motion abnormalities in echocardiography. Micro-vascular metabolism and altered coronary haemodynamics should be further exploded in this clinical entity in future studies.
