Total coronary occlusion: a different animal?

Provided collateralization is adequate, a chronic total coronary occlusion clinically imitates a 90% stenosis but is exempt from the risk of myocardial infarction. For angioplasty of vessels with chronic total coronary occlusion, technical difficulties and clinical risks are balanced against projected subjective benefit and amount of viable myocardium concerned. The primary success rate is approximately 65% and complications are rare because abrupt vessel reclosure may be common but is harmless. New Q wave infarction in that context has not been reported. The duration of occlusion is the most important predictor of success. The length of the occluded segment is also important. Recurrence averages 68% (21% reocclusion and 47% restenosis) and happens typically within 6 months. The high recurrence rate is due to competitive pressure exerted by collateral vessels and an often suboptimal local result. Even if the primary success rate of angioplasty in vessels with chronic total coronary occlusion can be improved by advanced technology and skill, the clinical yield will remain low compared with that of angioplasty of stenoses. Because low yield procedures must be low risk and low cost, there are definite limits to how sophisticated, risky and expensive new techniques can become. Derivatives of conventional balloon systems are likely to remain the equipment of first choice, perhaps complemented by mechanical drills. Although chronic total coronary occlusions are no clinical menace in contrast to stenoses, they frequently deserve revascularization and are the reason to select bypass surgery over angioplasty. These factors justify endeavors to improve recanalization techniques that help to refine coronary angioplasty of nontotal lesions, because total occlusion, albeit a different animal, is of the same species.