The calcium-channel blocker nicardipine can effectively reverse coronary slow flow (CSF)—“an under-recognized cause of chest pain”—according to the authors of a study published online Dec. 15 in the Journal of Invasive Cardiology.
Senior author Michael Savage, MD, and colleagues studied 30 patients who were found to have CSF in 49 total vessels. CSF was defined as delayed blood flow (TIMI flow grade 2 or lower) upon diagnostic angiography without obstructive coronary artery disease or other conditions known to limit coronary flow.
“First described in 1972, CSF may be more common than generally appreciated,” wrote Savage, the director of the cardiac catheterization lab at the Sidney Kimmel Medical College at Thomas Jefferson University, and coauthors. “CSF has been described in up to 7% of patients undergoing diagnostic angiography and may account for up to 4% of unstable angina admissions. The clinical course can be challenging, with recurrence of chest pain occurring in up to 80% of patients and hospital readmission in 20% within a 2-year follow-up period.”
After administering a 200 µg intracoronary bolus of nicardipine to the patients in their study and performing repeat angiographies, the researchers found the treatment successfully reversed CSF in all cases—at least in the short term. Every vessel with CSF demonstrated TIMI flow grade 3, and the TIMI frame count improved from an average of 47 at baseline to 15 following nicardipine administration.
“These results suggest that microvascular spasm may be responsible for this condition, which can be effectively reversed with a calcium channel blocker like nicardipine,” Savage said in a press release. “It’s a simple intervention that takes only a few seconds to administer, and helps diagnose the condition and treat it at the same time.”
Savage et al. hypothesized this method would work because it has proven effective in reversing no-reflow in PCI, which bears an angiographic resemblance to CSF.
The authors noted their study was limited by its small sample size and retrospective design. They also reiterated the need for future studies to examine the duration of nicardipine’s effect in increasing coronary flow and to evaluate whether oral calcium-channel blockers can help manage CSF over the long term.