A 44-year-old man presented with Canadian Cardiovascular Society (CCS) class II exertional angina. Both the physical examination and resting electrocardiogram were unremarkable. Depression of the ST segment in anterolateral derivations was observed during the exercise test, and coronary angiography revealed chronic total occlusion (CTO) of the proximal right coronary artery (RCA) with collateral flow from the distal left anterior descending artery (LAD) and bridging intraplaque collaterals from the proximal RCA. The LAD was diffusely diseased. A close up view of the intra-plaque channels with pooling of contrast within the lesion is shown in fig 1. We decided to proceed with percutaneous coronary intervention of the CTO.
The CTO in the proximal segment was crossed following several attempts with guidewire (0.014 inch PT2-MS, Boston Scientific, USA), and predilatation (at 10 atm for 30 s) with a balloon catheter (20/2.00 mm Maverick 2, Boston Scientific). This resulted in dilatation of the intraplaque collateral channel and was followed by stenting of the above mentioned lesion (23/3.50 mm, Xience V, Abbot, USA). Subsequently we performed stenting of type B1 lesion causing 80% luminal narrowing in the distal RCA segment (23/4.00 mm, Flex, Abbot) (fig 2).
This case demonstrates the presence of intraplaque collaterals in CTO, further supporting the microchannel scenario, which suggests that, in the presence of pre-existing micron channels, crossing of the CTO should not require any force. A “trial and error approach” of carefully steering and redirecting the guidewire should be employed until the true channel which connects the stump and the distal parent lumen is entered. Therefore, anyone dealing with a CTO must first try to “find a true way”.