An indeterminate occlusion duration predicts procedural failure in the recanalization of coronary chronic total occlusions.

Objectives: To identify the impact of occlusion duration (OD) and, in particular, an indeterminate occlusion duration (IOD) on immediate angiographic success and long-term clinical outcomes in patients undergoing chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

Methods: From May 2003 to October 2006, all patients having PCI for a CTO were consecutively registered. In addition to an assessment of procedural outcomes, patients were followed long-term for occurrence of major adverse cardiac events (MACE).

Results: 202 consecutive patients were included. Of these, 123 (60.9%) had a known OD while in the remaining 79 (39.1%), OD was indeterminate. Overall technical success was 82.7% and was lower in the IOD group (70.9% vs. 90.2%, P = 0.0004). An IOD was a predictor of procedural failure (adjusted OR 4.51, 95% CI 1.7-11.5, P = 0.002). An IOD (HR 2.59, 95%CI 1.08-6.23, P = 0.032) and procedural success (HR 0.26, 95%CI 0.11-0.60, P = 0.002) were the only independent predictors of long-term MACE. Patients with a failed PCI and an IOD had a 5-fold increased risk of MACE compared to those with known OD (37.0% vs. 7.1%, log rank P = 0.0036).

Conclusions: In addition to the traditional predictors of procedural success and clinical outcome, this study, for the first time uncovered the importance of OD and, in particular, of an IOD. Still, in patients who are successfully recanalized, a long or IOD bears the same low rate of MACE as the general CTO population while in patients with failed PCI, an IOD carries a considerable risk of adverse prognosis.