Date Published: June 12, 2018
Publisher: Public Library of Science
Author(s): Takao Konishi, Naohiro Funayama, Tadashi Yamamoto, Daisuke Hotta, Shinya Tanaka, Shuangtao Ma.
A high coronary artery calcium score (CACS) predicts a poor prognosis in patients with coronary artery disease. We examined the relationship between the bifurcation angle and the CACS of the left main (LM) and left anterior descending (LAD) arteries in patients suffering from chronic kidney disease (CKD).
We analyzed the data of 121 patients who underwent coronary computed tomography between October 2014 and June 2015 and whose estimated glomerular filtration rate (eGFR) was <60 ml/min/1.73 m2. The LM-LAD bifurcation angle was measured by 3-dimensional coronary computed tomography. The CACS of the LM-LAD arteries was also calculated. We excluded stent recipients and patient who had undergone coronary artery bypass graft surgery. In the overall sample, the mean ± standard deviation (range) LM-LAD bifurcation angle was 35.9 ± 11.4° (6.8–79.4°) and mean CACS was 227 ± 351 (0 to 1,695). The mean LM-LAD arteries angle was 40.3° ± 10.0° in 39 patients whose CACS was ≥200, versus 33.8° ± 11.6° in 82 patients with CACS <200 (p = 0.003). A weak, but positive correlation (r = 0.269, p = 0.003) was observed between the LM-LAD arteries angle and CACS of the LM-LAD arteries. By multiple variable analysis, hemoglobin A1c, triglycerides, eGFR and the LM-LAD arteries angle were independent predictors of a high CACS of the LM-LAD arteries. In patients with CKD, a wide LM-LAD arteries angle was associated with a high CACS of the LM-LAD arteries. The prognostic value of this observation warrants further evaluation.
In the past three decades, computed tomography angiography (CTA) has been adopted for its high spatial and temporal resolution and accuracy as a superior imaging test for the diagnosis of coronary artery disease [1–4]. Coronary CTA enables the visualization of coronary artery anatomy as well as the composition of coronary atherosclerotic plaques. The assessment of the left coronary bifurcation angle has gained clinical interest because the angulation of the left coronary bifurcation has been shown to influence the wall shear stress and cause disturbances of bloodstream followed by the atherosclerotic development at the bifurcation region [5–7]. Therefore, analyses of the bifurcation angles will provide clinically important information about the relationship between coronary atherosclerosis and coronary bifurcation angles. In previous studies, measurement of the left coronary bifurcation angle has been found useful to predict high-grade coronary stenoses [5, 6] and clinical outcomes after percutaneous coronary intervention in the left coronary artery [8–10]. Since the left anterior descending (LAD) coronary artery supplies approximately 50% of the left ventricular myocardial blood flow [11, 12], progression of atherosclerosis in that vessel might be associated with worse clinical outcomes than progression of disease in other epicardial arteries .
The main observations made in this study are 1) hemoglobin A1c, triglycerides, eGFR and the LM-LAD arteries angle were predictors of high CACS in patients suffering from CKD, and 2) in these patients, the CACS was higher when the LM-LAD arteries angle was ≥ than when it was <32.1°. To the best of our knowledge, this study is the first to a) find a correlation between the LM-LAD arteries angle and CACS in patients suffering from CKD, and b) compare the LM-LAD arteries angle with other predictors of high CACS by multiple variable analysis. It adds important anatomical information to the list of predictors of severe coronary calcifications. Therefore, its merit, as a predictor of clinical cardiovascular events in patients suffering from CKD warrant further evaluation. The results of this study suggest that, in patients suffering from CKD, a wide LM-LAD arteries angle is associated with a high CACS of the bifurcation. Measurement of that angle should be part of clinical practice to identify patients suffering from CKD at high risk of developing severe calcifications, which might burden their prognosis. Source: http://doi.org/10.1371/journal.pone.0198566