Background and aims Increasingly collateral channels have been used for retrograde wiring as a means of improving success rates in the recanalisation of complex CTOs.However the feasibility of wiring variable collateral channels and the risk of injury to important collateral channels is still to be definedTo conduct a systematic review and meta-analysis on the anatomy of the collateral circulation of the heart with specific reference to retrograde wiring in chronic total occlusions (CTO).

Methods and Results We searched publications from 1966 to June 2013 in PubMed, Ovid, EMBASE and the Cochrane database inserting a number of terms relating to the collateral circulation of the heart in CTOs. 17 case series (n range17–378) with a total of 1818 CTO revascularisation attempts fulfilled criteria for a study of retrograde wiring of collateral channels in CTOs. There were no randomised studies comparing a primary antegrade with a retrograde approach in any anatomical subset of CTO or those with previous failed antegrade wiring. Procedural CTO revascularisation success rates ranged from 67–90.6% and was strongly predicted by success of retrograde wiring. There was no temporal pattern in success rates of retrograde wiring or overall successful revascularisation or collateral channel used. (2007–2013), Figure 1. The septal perforator collaterals and epicardial channels were used in 75%(n = 1356) and 21%(n = 384) of cases respectively. Extraction of individual and group data according to operator selected collateral channel revealed greater success of retrograde wiring withseptal perforating channels (80%, n = 430/535) as compared to epicardial collateral channels (68.8%, n = 106/154). RR 1.16 (95% CI: 1.04, 1.30; p = 0.010). (Figure 2, forest plot) Although collateral/coronary perforation was not infrequent (n = 90, 5%) serious acute complications were uncommon; in the combined population 12 cases of cardiac tamponade (0.7%) requiring pericardiocentesis, and 2 deaths (0.1%).

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Abstract 73 Figure 1

Temporal pattern in collateral channel use and overall success rates of CTO revascularisation

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Abstract 73 Figure 2

Conclusions Our analysis demonstrates for the first time that septal perforator channels are significantly more likely to be successfully retrogradely wired compared to epicardial vessels when either is selected, on account of their anatomy, by the operator, as a route of access to the distal cap of a CTO. Successful retrograde wiring of collateral channels in selected patients undertaken by experienced CTO operators can significantly enhance the chances of revascularisation of complex CTOs with a low risk of acute serious complications.