Low-dose sildenafil shows therapeutic potential in primary coronary slow flow phenomenon

In the treatment of patients with primary coronary slow flow phenomenon (CSFP), the use of low-dose sildenafil daily appears to confer several benefits, including symptom improvement, blood pressure reduction, and enhanced exercise test parameters, according to the results of a pilot trial.

Twenty adult patients (average age 49 years, 65 percent male) who had a confirmed diagnosis of primary CSFP through coronary angiography and presented with typical angina pectoris with Canadian Cardiovascular Society (CCS) classes II–IV participated in the trial. These patients were randomly assigned to receive either 50-mg oral sildenafil or placebo daily for 12 weeks.

Researchers evaluated changes in functional capacity (metabolic equivalents [METs]), Duke treadmill score (DTS), and angina severity (Canadian Cardiovascular Society (CCS) class).

After 12 weeks of treatment, sildenafil yielded improvements in angina severity, with all patients showing no symptoms during regular physical activity (CCS I). In comparison, only 40 percent of patients in the placebo group achieved the same level of improvement (p=0.011).

Functional capacity was also significantly better in the sildenafil group. Mean METs increased from 9.9 at baseline to 13.1 at week 12 with sildenafil and remained unchanged from 9.56 to 9.63, respectively, with placebo (sildenafil vs placebo: median increase, 3.1; p=0.008).

Finally, sildenafil was associated with a significantly greater improvement in DTS scores compared with placebo (from 3 to 9.5 vs from 7 to 8), with a median increase of 5.5 points (p=0.01).

The findings highlight the potential of daily low-dose sildenafil as a therapeutic option for primary CSFP.