Date Published: June 12, 2019
Publisher: Public Library of Science
Author(s): Misato Chimura, Shinichiro Yamada, Yoshinori Yasaka, Hiroya Kawai, Yoshiaki Taniyama.
The benefit of revascularization of chronic total occlusion (CTO) in percutaneous coronary intervention (PCI) is controversial. On the other hand, left ventricular (LV) global longitudinal strain (GLS) is a more sensitive marker of LV myocardial ischemia and LV function than LV ejection fraction (EF). The purpose of this study was to investigate the impact of revascularization of CTO on LV function using LV GLS. A total of 70 consecutive patients (65.1±8.9 years, 59 males, LVEF 51.0±12.0%) with CTO who had a positive functional ischemia and underwent PCI, were included in this study. Echocardiography was performed before and 9 months after the procedure with conventional assessment including LV end-diastolic and end-systolic volume (LVEDV, LVESV), LVEF, and with 2DSTE analysis of GLS. Successful PCI was obtained in 60 patients (86%). There were no stent thromboses during follow-up. GLS showed a significant improvement 9 months after successful PCI (pre-PCI -12.4±4.1% vs. post-PCI -14.5±4.1%, P< 0.01), whereas in failed PCI group that did not change significantly (pre-PCI -13.2±4.2% vs. post-PCI -14.0±4.7%, P = 0.64). LVEF, LVEDV and LVESV did not change significantly during follow-up in both successful and failed groups. Successful PCI for CTO improved LV function, assessed by LV GLS.
Chronic total occlusions (CTO) are defined as lesions with TIMI (Thrombolysis in Myocardial Infarction) grade 0 flow for more than three months. CTO lesions are identified in 18.4% in patients undergoing elective percutaneous coronary intervention (PCI) in the absence of previous coronary artery bypass surgery or those presenting with acute myocardial infarction . Several previous studies reported the effect of successful PCI for CTO, such as improvement of quality of life, exercise capacity, and reducing the need for late CABG surgery [2, 3]. However the benefits of revascularization using PCI for CTO are still controversial. Two-dimensional speckle-tracking echocardiography (2DSTE) is emerging as a novel technique to allow the assessment of LV systolic and diastolic function through the quantification of active myocardial deformation [4–6]. The global longitudinal strain (GLS) assessed with 2DSTE, which evaluates the longitudinal myocardial deformation, is more reproducible than left ventricular ejection fraction (LVEF) or wall motion score index (WMSI), is advantageous over the color kinesis technique and is proven to be effective in detecting the LV myocardial ischemia [7–13]. Moreover in patients with cardiovascular disease, myocardial dysfunction occurs even if overall LVEF is preserved, and that may be associated with impaired LV longitudinal deformation . Accordingly, the purpose of this study was to investigate the impact of revascularization of CTO on LV function using LV GLS.
Between January 2009 and December 2013, a total of 70 CTO lesions (in 70 patients) were targeted, and 60 lesions were successfully revascularized with PCI, and 10 lesions were failed (Fig 1). No procedural complications (coronary perforation, cardiac tamponade or emergent cardiac surgery) were observed in any patients undergoing CTO-PCI attempt. During the 9-month from the procedure, there were no changes in prescribed medical treatment, such as beta-blockers, angiotensin receptor blockers or angiotensin converting enzyme inhibitors, and nitrates, and no cardiac resynchronization therapy and pacemaker were implanted.
In this study, we investigated the impact of revascularization of CTO on LV function using LV GLS. Successful PCI for CTO improved LV function assessed by LV GLS. To the best of our knowledge, this is the first study to demonstrate the comparison with successful and failed CTO-PCI patients with a positive functional ischemia before PCI, according to LV function evaluated with LV GLS before and after 9 month PCI.
Successful PCI for CTO improved LV function, assessed by LV GLS.