We assessed the ethnic differences in coronary atherosclerosis lesion morphology between white and Asian patients. Our hypothesis was that left main coronary artery (LMCA) disease was more focal and less complex in Asian than in Western white patients. We studied 99 Asian patients (Japan and South Korea) and 99 matched control United States white patients with a stable clinical presentation and >30% LMCA angiographic diameter stenosis by visual estimation. The matching parameters included age, gender, and diabetes mellitus. The vessel and lumen areas and calcium arc were analyzed every 0.5 mm and normalized for analysis length. Overall, 75.1% of the patients were men and 34.1% had diabetes. The patient age was 68.0 ± 10 years, with no differences between the Asian and white patients. The Asian patients had a lower prevalence of hyperlipidemia than the white patients (41.4% vs 81.8%; p <0.0001) and were smaller in size, and the white patients were more obese (body mass index 23.7 ± 2.6 vs 27.6 ± 4.1 kg/m 2 , p <0.0001). The Asian patients had a smaller lumen area (5.2 ± 1.8 vs 6.2 ± 14 mm 2 ; p <0.0001), larger vessel area (20.0 ± 4.9 vs 18.4 ± 4.4 mm 2 ; p <0.0001), and larger plaque burden (72 ± 10 vs 64 ± 12%: p <0.0001) at the minimum lumen site and over the entire LMCA length. The white patients had more calcification, whether assessed by the maximum arc (82° ± 74° vs 49° ± 45°; p <0.0001) or total length (3.6 ± 3.2 vs 2.1 ± 2.1 mm; p <0.0001). In conclusion, after matching well-known risk factors, there appeared to be ethnic differences in coronary atherosclerosis morphology between Asian and white patients, at least as it affected LMCA morphology.
Left main coronary artery (LMCA) disease is associated with a worse long-term prognosis. Although angiography continues to be the reference standard for assessing LMCA stenoses, intravascular ultrasound (IVUS) and fractional flow reserve studies have highlighted the inaccuracy of the angiographic assessment of LMCA disease. Furthermore, unlike angiography, IVUS examinations assess not only the lumen dimensions, but also disease of the vessel wall, including plaque burden, remodeling, and calcification. Recent studies have suggested that stent implantation into a LMCA stenosis is a viable alternative to coronary artery bypass grafting. Genetic factors appear to contribute to ethnic differences in the prevalence of coronary heart disease. In Asian countries, the mean total cholesterol levels are lower than those in Western countries. The purpose of the present analysis was to compare LMCA disease in Asian and white patients. We hypothesized that the LMCA disease would be more focal and have less calcification in Asian patients than in Western white patients.
Methods
We matched 99 Asian patients (67 from Showa University Northern Yokohama Hospitals, Yokohama, Japan, and 32 from Ajou University Hospital, Suwon, South Korea) and 99 white patients (Columbia University Medical Center, New York, New York) who had >30% LMCA angiographic diameter stenosis by visual estimation and who had undergone either preintervention or diagnostic IVUS imaging. The initial matching criteria were age, gender, and the presence of diabetes mellitus. The exclusion criteria were previous coronary artery bypass grafting, acute myocardial infarction or cardiogenic shock at presentation, and a calculated creatinine clearance <25 ml/min.
The risk factors for coronary artery disease included diabetes mellitus (medication-dependent, either oral hypoglycemic agents or insulin), hypertension, and hypercholesterolemia. Hypertension was defined as systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg or antihypertensive medication. The definition of hyperlipidemia included previously documented hypercholesterolemia (serum total cholesterol ≥240 mg/dl or serum triglycerides ≥200 mg/dl) or treatment with lipid-lowering drugs. The body mass index was calculated as the weight (kg)/height (m 2 ), and the body surface area was calculated using the Dubois formula: 0.20247 × height (m) 0.725 × weight (kg) 0.425 . The creatinine clearance was calculated as follows:
e C C r = ( 140 − A g e ) × Mass ( in kilograms ) × [ 0.85 if Female ] 72 × Serum Creatinine ( in m g / d L )
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