Intravascular ultrasound-guided treatment for angiographically indeterminate left main coronary artery disease: A long-term follow-up study

The purpose of this study was to evaluate the efficacy of an intravascular ultrasound (IVUS)-guided strategy for patients with angiographically indeterminate left main coronary artery (LMCA) disease. The assessment of LMCA lesions using coronary angiography is often challenging; IVUS provides useful information for assessment of coronary disease. Intravascular ultrasound was performed on 121 patients with angiographically normal LMCAs to determine the lower range of normal minimum lumen area (MLA), defined as the mean - 2 SD. We conducted IVUS studies on 214 patients with angiographically indeterminate LMCA lesions, and deferral of revascularization was recommended when the MLA was larger than this predetermined value. The lower range of normal LMCA MLA was 7.5 mm ². Of the patients with angiographically indeterminate LMCAs, 83 (38.8%) had an MLA <7.5 mm ², and 131 (61.2%) an MLA <7.5 mm ². Left main coronary artery revascularization was performed in 85.5% (71 of 83) of patients with an MLA <7.5 mm ² and deferred in 86.9% (114 of 131) of patients with an MLA <7.5 mm ². Long-term follow-up (mean 3.3 ± 2.0 years) showed no significant difference in major adverse cardiac events (target vessel revascularization, acute myocardial infarction, and death) between patients with an MLA <7.5 mm ² who underwent revascularization and those with an MLA <7.5 mm ² deferred for revascularization (p = 0.28). Based on outcome, the best cut-off MLA by receiver operating characteristic was 9.6 mm ². Multivariate predictors of cardiac events were age, smoking, and number of non-LMCA vessels diseased. Intravascular ultrasound is an accurate method to assess angiographically indeterminate lesions of the LMCA. Furthermore, deferring revascularization for patients with a minimum lumen area <7.5 mm ² appears to be safe.