Objective Coronary drug-eluting stents have been implanted in small renal arteries (<5.0 mm) to reduce restenosis. The aim of this study is to investigate the anatomic basis for off label use of coronary stent in renal artery in swine.

Methods Nine animals were examined in this study. Paired segments of coronary and renal artery were sampled from the same animal. Tunica media circumference referred to length of demarcation between tunica media and adventitia. Area of intima and tunica media was the area between intima circumference and tunica media circumference. Wall thickness (from intima to tunica media) was calculated as mean of four measurement in different directions. Inner diameter was calculated as intima circumference/π. Corrected wall thickness was calculated as wall thickness/inner diameter ×100.

Results Intima circumference and inner diameter were not significantly different between coronary and renal arteries. Tunica media circumference (7.00±0.73 mm vs 8.30±0.48 mm), wall thickness (0.34±0.05 mm vs 0.50±0.11 mm), area of intima and tunica media (2.09±0.41 mm² vs 3.38±0.73 mm²), and corrected wall thickness (21.4±1.96 vs 32.0±9.70) were significantly less in coronary arteries than renal arteries.

Conclusion It seems that muscle layer in renal artery is stronger than coronary artery. Renal artery needs stronger radial force than coronary artery. The off label use of coronary stent in renal artery might be inappropriate.