Effects of Nicorandil on Angina Symptoms in Patients With Coronary Slow Flow

Nicorandil Versus Nitroglycerin for Symptomatic Relief of Angina in Patients With Slow Coronary Flow Phenomenon Visited in Imam Reza Hospital, Mashhad, Iran

Slow coronary flow is an angiographically diagnosed phenomenon defined as delayed opacification of epicardial arteries in the absence of significant arterial narrowing and blockade. Endothelial dysfunction at the level of microarteries have been proposed as the main pathological mechanism in this regard. Available evidence suggest that standard anti-angina medications (e.g. nitroglycerin) that solely target large coronary trunks might not provide adequate symptomatic relief in patients with slow coronary flow phenomenon. It is hypothesized that anti-angina medications which exert vasodilatory effects in large coronary arteries as well as small dividing branches might be superior to nitroglycerin in amelioration of angina symptoms. The present randomized clinical trial was thus designed and conducted to compare the short-term efficacy of nicorandil (a dual-acting anti-angina medication with effects on both large and small coronary vessels) with nitroglycerin in a group of patients with slow coronary flow presented with frequent angina episodes.

sustained-release glyceryl trinitrate (6.4mg tablets, two times a day) + standard treatment (an anti-platelet agent, a beta-blocker, an angiotensin converting enzyme inhibitor, and a 3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitor)

nicorandil (10mg tablets, two times a day) + standard treatment (an anti-platelet agent, a beta-blocker, an angiotensin converting enzyme inhibitor, and a 3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitor)

One month after treatment, patients were asked to determine the frequency of angina episodes in the preceding week.

One month after treatment, patients were asked to determine the average intensity of chest pain in experienced episodes using a Likert-type scale of 0 to 10, where 0 indicated lowest intensity/no pain and 10 indicated the highest possible pain experienced.

One month after treatment, patients were asked to describe the angina episode and based on their descriptions, the CCS class of chest pain was determined. Based on patient's description of the anginal episodes, angina severity was classified into one of CCS class I (angina only with prolonged demanding physical activity), Class II (Slight limitation, with angina only during vigorous physical activity), Class III (Symptoms with everyday living activities), or class IV (angina at rest).

Patients were asked and underwent physical examination regarding the common and uncommon side effects attributed to anti-angina medications

Inclusion Criteria: on coronary angiographic studies, arterial narrowing did not exceed 50% in any of the three main coronary arteries; ( a delayed opacification in at least one of the main coronary arteries was documented. Delayed opacification was defines as corrected TIMI frame count > 23 fps Exclusion Criteria: comorbid cardiovascular condition other than mild coronary atherosclerosis and coronary slow flow refusal to participate discontinuation of treatment not returning for the follow up visit