Stimulating Extracardiac Collaterals via Right Internal Mammary Artery Occlusion
Another Step Into an Undiscovered Country
This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.
But that the dread of something after death, The undiscovered country from whose bourn [boundary] No traveler returns, puzzles the will
—The Tragedy of Hamlet Prince of Denmark, Act III, Scene I
—William Shakespeare (1564–1616)
In their search to find ways to reduce ischemia and possibly prevent death in patients with refractory angina, Stoller and Seiler, in 2014, moved into an undiscovered country and advanced a novel therapeutic strategy involving stimulation of extracardiac collaterals through occlusion of the internal mammary artery.1 In this issue of Circulation: Cardiovascular Interventions, Stoller and Seiler2 take another step from temporary internal mammary artery (IMA) occlusion now to report on the effects of permanent percutaneous right internal mammary artery (RIMA) occlusion.
See Article by Stoller and Seiler
In the current study,2 50 patients with coronary disease underwent 1-minute serial right and left coronary artery balloon occlusion at baseline and then again 6 weeks after placement of a distal RIMA vascular occluding device. The primary end point was the change in collateral flow index (CFI) derived from pressure, (CFIpressure, [Pocclusion−Pvenous]/[Paorta−Pvenous]), using a pressure sensor guidewire distal to the balloon occlusion. Secondary end points included fractional flow reserve, degree of ST-segment elevation from an intracoronary electrogram, and anginal symptoms during the 1 minute of ischemia with coronary occlusion.
After 6 weeks of follow-up, CFI increased in the right coronary artery (RCA) after RIMA occlusion (from 0.071±0.08 to 0.132±0.12; P<0.0001), whereas the left anterior descending coronary artery CFI was unchanged (0.11±0.09 to 0.08±0.08; P=NS). Concomitant with the increased RCA CFI was a decrease in the intracoronary ST-segment elevation during RCA occlusion, a response not demonstrated in the left anterior descending artery. Likewise, angina tended to be less in …