Impact of Heterogeneous Overlapping Drug-Eluting Stents on the Arterial Responses of Rabbit Iliac Arteries: A Comparison With Overlapping Bare Metal Stents

BACKGROUND AND OBJECTIVES: Although the use of heterogeneous overlapping drug-eluting stents (DES) is not uncommon in clinical practice, whether the implantation sequences of heterogeneous DES will influence the endothelialization or arterial responses differently remains unclear. MATERIALS AND METHODS: Twenty-one rabbits were randomized to receive overlapping stents in the iliac artery for 3 months {distal sirolimus-eluting stent (SES, Cypher(TM))+proximal paclitaxel-eluting stent (PES, Taxus(TM)) (C+T, n=7), distal Taxus+proximal Cypher (T+C, n=7) and bare metal stent (BMS)+BMS (B+B, n=7)}. Endothelial function was evaluated by the acetylcholine provocation test during follow-up angiography. Histopathological changes in proximal, overlapped, and distal stented segments were evaluated. RESULTS: Although the overall angiographic outcomes were comparable, late loss (mm) in the distal stented segment was higher in the B+B (0.39+/-0.07) and C+T (0.40+/-0.20) than that in the T+C (0.06+/-0.02) group (p<0.001). The incidence of acetylcholine-induced spasm was higher in the DES groups compared with BMS, regardless of the implantation sequences (85.7% in C+T vs. 14.3% in B+B vs. 71.4% in T+C, p=0.017). Notably, only the distal Cypher implantation group (C+T) had three cases of stent fracture. A histopathological analysis showed that despite similar arterial injury scores, Taxus and Cypher stents had higher inflammatory reactions at the overlapped and distal segments compared with those of BMS. CONCLUSION: Despite similar arterial injury, higher inflammatory reactions were observed in overlapping DES segments regardless of the implantation sequence compared with that of BMS. Moreover, DES was associated with impaired endothelial function on the adjacent non-stented segments.

Impact of Smoking and Smoking-Related Parameters on Acetylcholine-Induced Coronary Artery Spasm

BACKGROUND AND OBJECTIVES: Smoking has been known to be an independent risk factor of the coronary morbidity induced by coronary artery endothelial dysfunction, but its detailed impact, including the duration and amount of smoking on coronary artery spasm, has not been clarified yet. We investigated the incidence of acetylcholine (Ach)-induced coronary artery spasm according to smoking and the smoking-related parameters. SUBJECTS AND METHODS: The study consisted of 306 patients (163 males, age: 56.1+/-11.2 years), without significant coronary artery disease underwent Ach provocation testing by injecting incremental doses of 20, 50 and 100 ug Ach into the left coronary artery. Significant coronary artery spasm was defined as focal or diffuse severe transient luminal narrowing (>75%) with/without chest pain or ST-T change of the EKG. The impact of conventional risk factors, including smoking and the smoking-related parameters, on coronary artery spasm was analyzed. RESULTS: The conventional risk factors of coronary atherosclerosis, including hypertension, DM and hyperlipidemia, were numerically higher in the provocation (+) group, but the differences were not statistically different between the two groups. Only smoking itself was significantly higher in the provocation (+) group whereas the smoking duration, amount and the duration of quitting smoking were not different between the two groups. CONCLUSION: Smoking is known to be an independent risk factor of coronary artery spasm, but smoking-related parameters such as the smoking duration, the amount and the duration of quitting smoking were not associated with coronary artery spasm.