Prospective application of pre-defined intravascular ultrasound criteria for assessment of intermediate left main coronary artery lesions results from the multicenter LITRO study

Abstract

Objectives: This study is a prospective validation of 6 mm(2) as a minimum lumen area (MLA) cutoff value for revascularization of left main coronary artery (LMCA) lesions.

Background: Lesions involving the LMCA are prognostically relevant. Angiography has important limitations in the evaluation of LMCA lesions with intermediate severity. An MLA of 6 mm(2) assessed by intravascular ultrasound has been proposed as a cutoff value to determine lesion severity, but there are no large studies evaluating the prospective application and safety of this approach.

Methods: We have designed a multicenter, prospective study. Consecutive patients with intermediate lesions in unprotected LMCA were evaluated with intravascular ultrasound. An MLA <6 mm(2) was used as criterion for revascularization.

Results: A total of 354 patients were included in 22 centers. LMCA revascularization was performed in 90.5% (152 of 168) of patients with an MLA <6 mm(2) and was deferred in 96% (179 of 186) of patients with an MLA of 6 mm(2) or more. A large scatter was observed between both groups regarding angiographic parameters. In a 2-year follow-up period, cardiac death-free survival was 97.7% in the deferred group versus 94.5% in the revascularized group (p = 0.5), and event-free survival was 87.3% versus 80.6%, respectively (p = 0.3). In the 2-year period, only 8 (4.4%) patients in the deferred group required subsequent LMCA revascularization, none with an infarction.

Conclusions: Angiographic measurements are not reliable in the assessment of intermediate LMCA lesions. An MLA of 6 mm(2) or more is a safe value for deferring revascularization of the LMCA, given the application of the clinical and angiographic inclusion criteria used in this study.