MUNICH - A joint Swedish and U.K. study involving CT angiography and calcium scoring has found that angina patients of South Asian origin have more aggressive and diffuse arterial calcification compared with Caucasians, especially those older than age 50.
Ethnic differences in the prevalence and severity of coronary artery disease (CAD) or coronary artery calcification (CAC) have been noted, Dr. George Koulaouzidis from the Heart Centre and the department of public health and clinical medicine at Umeå University in Sweden, reported at this week's European Society of Cardiology (ESC) annual meeting. South Asians are one of the largest ethnic groups at risk of CAD, but they are underrepresented in previous research.
"We retrospectively studied 101 symptomatic angina patients of South Asian origin -- India, Pakistan, Sri Lanka, Nepal, and Bangladesh -- who underwent CT coronary angiography between December 2009 and April 2011 and compared them with 101 consecutive symptomatic Caucasians matched for age, gender, and CAD risk factors," he explained. "Imaging was performed using a 640-slice, 320-row CT scanner with 0.5-mm detector elements, 350 msec of gantry rotation time, and up to 16 cm of coverage in the Z direction."
No significant differences were found between the two groups in age, CAD risk factors, and CAC prevalence. The left anterior descending artery was the predominantly affected artery, with plaques causing more than 25% of obstruction in both groups.
Compared with Caucasians, South Asians had a higher mean CAC score (156 ± 27.4 versus 25.4 ± 6.2), higher mean number of affected coronary artery segments (1.9 ± 2.3 versus. 1.0 ± 1.6), higher incidence of three-vessel disease (25.7% for South Asians, 5.9% for Caucasians), and higher incidence of obstructive CAD (19.8% for South Asians, 5.76% for Caucasians).
In the 37 patients age 50 or younger, the researchers found no significant differences between the two groups in mean CAC score, number of affected segments, and CAD severity and extent. In those older than 50, South Asians had a higher mean CAC score (226 versus 35.9), number of affected segments, and a greater incidence of obstructive CAD (37.5% versus 9.4%), as well as three-vessel disease (37.5% for South Asians, 9.4% for Caucasians). Single-vessel disease was far more common in Caucasians (15.6% for South Asians, 39% for Caucasians).
"This difference [in coronary artery calcification] is age-related, despite similar conventional cardiovascular risk factors," Koulaouzidis concluded. "Our cohort included only patients with stable CAD; therefore, findings should not be extrapolated to patients with acute coronary syndrome."
For further details about this study, go to the International Journal of Cardiology (15 June 2012, Epub ahead of print).
