The relationship between the contralateral collateral supply and myocardial viability on cardiovascular magnetic resonance: can the angiogram predict functional recovery?
BACKGROUND
A collateral circulation which supplies a myocardial territory, subtended by a chronic total occlusion (CTO), may be observed at invasive coronary angiography. The prognostic and protective role of such collateralisation is well demonstrated suggesting that a good collateral circulation may be a predictor of myocardial viability, but current evidence is discrepant. The aim of this study is to assess the relationship between collateralisation from the contralateral epicardial vessels and myocardial viability by cardiovascular magnetic resonance (CMR).


METHOD
Consecutive patients with CTO having had both CMR and invasive coronary angiography were retrospectively identified. The collateral circulation was graded with the Cohen and Rentrop classification. CMR images were graded per segment for wall motion (1: normal/hyperkinetic, 2: hypokinetic, 3: akinetic, or 4: dyskinetic) and wall motion score index (WMSI) was calculated. The segmental transmurality of late gadolinium enhancement was scored as 1 (0%), 2 (1-25%), 3 (26-50%), 4 (51-75%) and 5 (76-100%).


RESULTS
A good collateral circulation was more likely to supply viable myocardium (p=0.01). There was no relationship between collateral circulation supply and wall motion score index (WMSI), however, increasing transmurality of LGE was significantly associated with higher mean WMSI representing increasing dysfunctional myocardium (p<0.001).


CONCLUSION
The presence of collateral coronary circulation at angiography predicts the presence of viability on cardiovascular MRI, with a gradation of greater viability associated with improving Rentrop grade. A collateral circulation at angiography should, therefore, prompt more formal assessment of viability and consideration of revascularisation in order for the patient to obtain the associated functional and prognostic improvement.
['Ripley|David P|DP|', 'Gosling|Oliver E|OE|', 'Bhatia|Loke|L|', 'Peebles|Charles R|CR|', 'Shore|Angela C|AC|', 'Curzen|Nick|N|', 'Bellenger|Nick G|NG|']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D003097:Collateral Circulation D017023:Coronary Angiography D003331:Coronary Vessels D005260:Female D006801:Humans D019028:Magnetic Resonance Imaging, Cine D008297:Male D008875:Middle Aged D009206:Myocardium D011237:Predictive Value of Tests D020127:Recovery of Function D012189:Retrospective Studies
Viability Collateral circulation Chronic total occlusion Magnetic resonance imaging