Related Experiment Video
Updated: Jun 14, 2025
Interventional Diagnostic Procedure: A Practical Guide for the Assessment of Coronary Vascular Function
Published on: March 15, 2022
Sildenafil's effectiveness in the primary coronary slow flow phenomenon: a pilot randomised controlled clinical trial
Abbas Andishmand1, Seyedmostafa Seyedhosseini1, Seyedeh Mahdieh Namayandeh2,3
1Yazd Cardiovascular Research Center, Non-communicable Diseases Research Institute, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Insights
Sildenafil significantly improved angina severity and functional capacity in patients with coronary slow flow phenomenon (CSFP). This pilot study suggests daily low-dose sildenafil as a potential treatment for CSFP.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Coronary slow flow phenomenon (CSFP) is linked to chest pain, myocardial infarction, and sudden cardiac death.
- Optimal treatment for primary CSFP remains undefined, necessitating further research.
Purpose of the Study:
- To evaluate the effectiveness of sildenafil in treating primary CSFP.
- To assess sildenafil's impact on angina severity, functional capacity, and exercise tolerance.
Main Methods:
- A 12-week, triple-blind, randomized, placebo-controlled trial involving 20 patients with primary CSFP.
- Patients received either 50 mg daily oral sildenafil or a placebo.
- Primary outcomes included changes in angina severity (CCS class), functional capacity (METs), and Duke treadmill score (DTS).
Main Results:
- Sildenafil group showed significant improvement in angina severity, with all patients reaching CCS class I (asymptomatic).
- The sildenafil group experienced a significant increase in functional capacity (METs) and Duke treadmill score (DTS) compared to placebo.
- Median METs increased by 3.1 and median DTS by 5.5 in the sildenafil group versus minimal changes in the placebo group.
Conclusions:
- Daily low-dose sildenafil is a promising therapeutic option for primary CSFP.
- Sildenafil effectively alleviates symptoms and improves exercise tolerance in patients with CSFP.
Background:
On the one hand, the primary coronary slow flow phenomenon (CSFP) can cause recurrence of chest pain, prompting medical examinations and further healthcare costs, while on the other hand, it can lead to myocardial infarction, ventricular arrhythmia and sudden cardiac death. Nevertheless, there is not any agreement on the optimal treatment for primary CSFP, so we decided to examine the effectiveness of sildenafil in this context.
Methods:
This pilot study is a 12-week, triple-blind, randomised, placebo-controlled trial for receiving either 50 mg daily oral sildenafil or placebo. Twenty eligible patients aged 30-70 years from a tertiary hospital in Yazd were randomly allocated in a 1:1 ratio to two groups. The primary outcomes were the alterations in functional capacity (metabolic equivalents, METs), Duke treadmill score (DTS) and angina severity (Canadian Cardiovascular Society (CCS) class). The study protocol registration code is IRCT20220223054103N1.
Results:
The angina severity in the Sildenafil group improved, with all receivers achieving a state of being asymptomatic during regular physical activity (CCS I). Whereas just 40% of the recipients in the placebo group achieved the same level of improvement (p=0.011). Mean METs at baseline were 9.9 (SD: 3.1) and at week 12 were 13.1 (SD: 3.3) for sildenafil and 9.56 (SD: 2.1) and 9.63 (SD: 2.4) for placebo (difference favouring sildenafil with a median increase of 3.1 (IQR: 1.1 to 4.1, p=0.008)). Median DTS scores at baseline were 3 (IQR: 0 to 9) and at week 12 were 9.5 (IQR: 7.75 to 15) for sildenafil and 7 (IQR: -1.5 to 9.25) and 8 (IQR: 1.5 to 11.25) for placebo (difference favouring sildenafil with a median increase of 5.5 (IQR: 1 to 9.2, p=0.01)).
Conclusions:
We suggest that a daily low dose of sildenafil could be a valuable therapeutic option for primary CSFP.
Trial Registration Number:
IRCT20220223054103N1.
Related Concept Videos
01:28Treatment for Pulmonary Arterial Hypertension: Phosphodiesterase Inhibitors
Among the PDE5 inhibitors, sildenafil (Revatio) stands out as a competitive and selective inhibitor. It operates by elevating cellular levels of cGMP and augmenting signaling through the cGMP-PKG pathway, promoting vasodilation. Upon oral...
01:25Antianginal Drugs: Calcium Channel Blockers and Ranolazine
CCBs, a diverse class that includes dihydropyridines (nifedipine) and diphenylalkylamines (verapamil and diltiazem), exert their effect by blocking calcium channels in cardiac and smooth muscle cells. This...
01:16Antianginal Drugs: Nitrates and β-Blockers
Organic nitrates, such as nitroglycerin, play a pivotal role. Once metabolized, they liberate nitric oxide, a molecular marvel. Nitric oxide triggers guanylyl cyclase and augments cGMP production. This biochemical cascade orchestrates the relaxation of vascular smooth muscles, ushering in vasodilation and enhancing coronary blood flow....
01:28Nitric Oxide Signaling Pathway
01:23Antihypertensive Drugs: Vasodilators