Relation Between Coronary “Steal” and Contractile Function at Rest in Collateral-Dependent Myocardium of Humans With Ischemic Heart Disease

Abstract

Background-We tested the hypothesis that rest asynergy in collateral-dependent myocardium correlates with coronary steal. Methods and Results-PET with [13 N]ammonia measured myocardial blood flow and flow reserve in 15 patients with symptomatic chronic ischemic heart disease. Coronary angiography assessed stenosis severity and collateral blood supply. Echocardiography or contrast ventriculography evaluated regional wall motion. Collateral-dependent segments with normal flow at rest and supplied by coronary vessels having Յ50% diameter stenosis were studied. Steal was defined as a decline in myocardial blood flow with adenosine Ն0.15 mL ⅐ min Ϫ1 ⅐ g Ϫ1 versus rest. Blood flow at rest in asynergic, collateral-dependent segments with steal (1.15Ϯ0.35 mL ⅐ min Ϫ1 ⅐ g Ϫ1 ) exceeded (PϽ0.0001) that of asynergic segments without steal (0.81Ϯ0.24) and those with normal contraction (0.77Ϯ0.18). Although the flow reserve ratio of segments with normal contraction (1.8Ϯ0.8) exceeded that of asynergic ones with (0.6Ϯ0.1) or without (1.3Ϯ0.4) steal, overlap was great. Correlation between basal contraction and flow reserve ratio in collateral-dependent myocardium was significant but weak (rϭ0.45, PϽ0.001). However, segments demonstrating "steal" with adenosine manifested asynergy in 22 of 23 collateral-dependent segments versus 24 of 39 nonsteal segments ( 2 ϭ7.10, PϽ0.01). Conclusions-Although myocardial flow reserve in collateral-dependent segments with normal contraction exceeded that of asynergic segments, overlap was great. However, in patients with angina or congestive heart failure, left ventricular segments demonstrating steal with adenosine almost always exhibit asynergy at rest. Thus, coronary steal may play an important role in the pathogenesis of chronic contractile impairment at rest, whereas simple reduction of flow reserve may be less important in selected patients. (Circulation. 1999;99:2510-2516.)

Direct Assessment of Coronary Steal and Associated Changes of Collateral Hemodynamics in Chronic Total Coronary Occlusions

“…1,4,5,12,13 Coronary steal was observed in one third of patients. Another one third had a collateral flow reserve Ͼ1.…”

“…When group S is compared with quantitative PET studies, the values of collateral flow reserve (0.65Ϯ0.17) are in a similar range. 5,13 In patients without Abbreviations as in Figure 1. P values for changes within groups; difference between group N and S, *PϽ0.05; between group N and R, †PϽ0.05; between group S and R, ‡PϽ0.05.…”

“…1,2 In some patients, microvascular vasodilation during exercise or pharmacological stimulation leads to a decrease of blood flow to the collateral-dependent myocardium, an observation described as coronary steal. [3][4][5][6][7][8][9] This becomes clinically relevant when specific drugs are prescribed for patients with coronary artery disease. 10 In humans, coronary steal can be detected noninvasively by perfusion scintigraphy.…”

Low whole-body insulin sensitivity in patients with ischaemic heart disease is associated with impaired myocardial glucose uptake predictive of poor outcome after revascularisation

“…Assessment of relative myocardial glucose metabolism by 18 F-FDG and blood flow by nitrogen-13 ammonia ( 13 NH 3 ) is of prognostic value in patients with impaired LV contractile function undergoing coronary artery bypass graft surgery (CABG) [9,10,11]. Patients who have myocardial areas with increased myocardial 18 F-FDG uptake in relation to 13 NH 3 uptake (PET-mismatch) appear to benefit more from CABG than do patients in whom myocardial areas show a concordant decrease in 18 F-FDG and 13 NH 3 uptake (PET-match).…”

Physiology and Pathophysiology of Coronary Circulation

“…Coronary steal may occur from the subendocardium as a result of vasodilatation of subepicardial vessels (transmural coronary steal) (Maseri 1995;Hamasaki et al 1997) or from collateralized territories, as a result of arteriolar dilatation in the territory of the supplying artery, in particular when this is also stenosed (lateral coronary steal) (Holmvang et al 1999). …”