23 The influence of collateral regression post coronary chronic total occlusion (cto) percutaneous coronary intervention (pci) on donor vessel coronary pressure-derived measurements

Background There is strong evidence of FFR-guided treatment in multi-vessel disease. The presence of a concomitant CTO may influence the FFR measurement in donor vessel. We sought to investigate the influence of collateral regression after successful CTO recanalisation on donor vessel pressure-derived indices. Methods 28 out of 34 consecutive patients underwent successful PCI to RCA CTOs and completed the follow up study (at 3 months post CTO-PCI). Resting Pd/Pa,iFR and FFR were measured pre and post successful CTO PCI and at follow-up in donor vessels. Results The mean resting Pd/Pa, iFR and FFR pre and post-RCA CTO PCI and at follow-up procedures in major donor vessel were (0.893, 0.862, 0.764), (0.907, 0.886, 0.753) and (0.918, 0.901, 0.787) respectively. The mean resting Pd/Pa, iFR and FFR pre and post-RCA CTO PCI and at follow-up procedures in minor donor vessel were (0.979, 0.966, 0.890), (0.983, 0.979, 0.880) and (0.981, 0.974, 0.898) respectively. Changes in pressure-derived indices are summarised in table 1. Conclusion Successful recanalisation of a RCA CTO results in a significant increase in coronary pressure-derived indices of the major donor vessel at follow-up associated with a regression of collateral function. The expected change and the optimal timing to perform PCI in donor vessel should be considered when planning multi-vessel revascularisation in this setting.