Coronary slow flow is one of the most unfamiliar causes of chest pain of cardiac origin and heart attack. Chest pain contributes to frequent emergency room visits and is a leading cause of increasing health-care costs. An under-recognized cause of chest pain, the coronary slow-flow (CSF) phenomenon is characterized by delayed coronary opacification during diagnostic angiography in the absence of epicardial coronary artery disease (CAD).
A new study published in the Journal of Invasive Cardiology has reported a simple technique to effectively treat coronary slow flow (CSF). They have found that intracoronary nicardipine, a calcium channel blocker. appears highly effective in reversing spontaneous Coronary slow flow,CSF .
While the pathophysiology of CSF is not fully understood, abnormally elevated microvascular resistance appears to be an important feature. It is identified by angiogram of the heart, revealing arteries that fill with blood more slowly than normal, even in the absence of fatty plaque deposits. But what causes the condition, and why in 80 per cent of cases patients experience additional episodes of chest pain, is still unknown.
When the researchers first saw the condition on angiograms of their patients, it appeared similar to the no-reflow phenomenon caused by microvascular spasm during coronary angioplasty procedures. Since that condition could be treated with a drug called nicardipine, the investigators hypothesized that CSF may be reversed by intracoronary (IC) administration of nicardipine. Nicardipine, a dihydropyridine calcium-channel blocker with selective vasodilatory effects, has been shown to increase coronary blood flow and reverse no-reflow complicating PCI. The study was conducted to assess the effect of IC nicardipine on the CSF phenomenon.
“One of the biggest issues with the coronary slow flow is that many cardiologists aren’t familiar with it and don’t know what to look for to diagnose it,” said senior author Michael Savage, MD, Director of the Cardiac Catheterization Lab at the Sidney Kimmel Medical College at Thomas Jefferson University. “Here we’ve shown that once you do recognize it, the condition can be treated with an existing and safe medical intervention that reverses the problem.”
The researchers assessed the effect of IC nicardipine on CSF in 30 patients. Nicardipine was administered as a 200 µg IC bolus, after which repeat angiography was performed. Coronary flow before and after nicardipine was evaluated by TIMI flow grade and corrected TIMI frame count (TFC) assessments.
The investigators found a total of 49 blood vessels with slow blood flow. After treatment with nicardipine, all of the vessels showed normalized blood flow.
According to the researchers, the results suggest that microvascular spasm may be responsible for this condition, which can be effectively reversed with a calcium channel blocker like nicardipine. which is a simple intervention that takes only a few seconds to administer, and helps diagnose the condition and treat it at the same time.”
The study concluded that intracoronary nicardipine appears highly effective in reversing spontaneous CSF and warrants the need for further studies to find out whether the one-time treatment reverses the condition permanently, or whether patients would benefit from long-term use of an oral calcium channel blocker.
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