IVUS determination of normal left main stem artery size and plaque burden, and correlation with body surface area in...

There is a scarcity of data regarding the normal size of the left main stem coronary artery (LMS) in the Indian population; further data are needed to help determine the optimal device size during percutaneous coronary intervention (PCI).

The aim of our study was to determine the normal size of the LMS and to calculate the mean plaque burden (PB) in the left main arteries which are angiographically normal or insignificantly diseased, using intravascular ultrasound (IVUS). We hoped to establish a correlation between LMS size and body surface area (BSA).

We collected demographic and coronary artery data from 140 patients who underwent IVUS-guided PCI in the left anterior descending and circumflex arteries over a 2-year period from 2019 to 2020, where a pullback sequence of the LMS was available. The reference and luminal vessel diameters, the reference and luminal vessel areas and the mean plaque burden (PB) were obtained. Regression analysis was used to develop a correlation between BSA and LMS diameter.

The IVUS-determined mean reference diameter of the LMS was 5.53±0.63 mm and the mean luminal diameter was 4.62±0.65 mm. The mean reference vessel area was 24.79±5.5 mm² and the luminal vessel area was 17.19±4.89 mm². The mean PB was found to be 29.21% in patients with an angiographically normal left main and 32.29% in patients with angiographically insignificant left main stenosis. A linear correlation was noted between the left main reference and luminal vessel diameters; the correlation equations derived were 3.57+1.01 BSA and 2.95+0.87 BSA, respectively.

The mean reference and luminal diameters of LMS in the Indian population are on par with the size of LMS in other ethnicities. The vessel compensates for up to 40% PB with vessel remodelling. Hence, a PB of 40% is a good landing zone for stent deployment.