There is a widespread belief that coronary arteries are smaller in Indo-Asi
ans. The aim of the present study was to compare the size of atheroma-free
proximal and distal epicardial coronary arteries of Indo-Asians and Caucasi
ans. We analysed normal coronary angiograms from 77 Caucasians and 39 Indo-
Asians. The two groups were comparable for dominance of the coronary arteri
es. Indo-Asian patients had generally smaller coronary arteries, with a sta
tistically significant difference in the mean diameters of the left main co
ronary artery, proximal, mid and left anterior descending, and proximal and
distal right coronary artery segments. There was a non-significant trend t
owards smaller coronary artery segment diameters for the distal left anteri
or descending, proximal and distal circumflex, and obtuse marginal artery s
egments. However, after correction for body surface area, none of these dif
ferences in size were statistically significant. Thus, the smaller coronary
arteries in Indo-Asian patients were explained by body size alone and were
not due to ethnic origin per se. This finding nevertheless has important t
herapeutic implications, since smaller coronary arteries may give rise to t
echnical difficulties during bypass graft and intervention procedures such
as percutaneous transluminal coronary angioplasty, stents and atherectomy.
On smaller arteries, atheroma may also give an impression of more severe di
sease than on larger diameter arteries.