Coronary collaterals provide more than half of normal perfusion in patients with coronary artery disease - quantification by myocardial perfusion SPECT during elective balloon occlusion

Abstract Funding Acknowledgements Type of funding sources: None. BACKGROUND The coronary collateral circulation is a preformed network anastomotic connections acting as "natural bypass" mechanism. Whilst the prevalence collaterals varies between species, approximately 25% patients have angiographically visible robust at time ST elevation myocardial infarction. While presence associated with improved outcomes, magnitude perfusion which can be provided by remains uncertain. PURPOSE aim was to quantify during experimental balloon occlusion in CAD. METHODS study approved local investigational review board, and all informed consent. Patients without prior infarction, bypass surgery, or undergoing elective percutaneous transluminal angioplasty (PTCA) single epicardial vessel, underwent two scans 99mTc-sestamibi single-photon emission computed tomography (SPECT). All subjects least three minutes verified complete occlusion, an intravenous injection radiotracer administered, followed SPECT imaging. A second imaging performed 24 hours after PTCA. RESULTS included 21 (median [interquartile range] age 70 [56-74] years, 52% male). degree diameter stenosis treated vessels ranged from 60-99%, successful PTCA mean 5-minute time, resulting ?20% residual cases. were 6 LAD, 5 LCx, 10 RCA. For cohort, size defect 16 [8-30]% LV rest within 64 [58-68]% normal that region. Collateral negatively correlated (R2 = 0.85, p < 0.001), but did not differ sex (p 0.27) 0.58). CONCLUSIONS: This first describe microvascular On average, despite absence vessels, provide 60% reaches jeopardized myocardium occlusion. much higher than previously speculated. previous using microspheres dogs found setting occluded vessel 6% normal. By comparison, current ten times greater Figure.