Several kinds of stents have shown their safety and efficacy to treat acute or subacute closure after balloon angioplasty as well as to reduce restenosis rate. However, one of the limitations of stents is difficult to deploy especially in tortuos vessels, lesions at a bend, and distal to previously deployed stents. The Micro stent II, which was one of the most recently developed stents, ia a rapid-exchage balloon expandable stainless steel stent with a zigzag design connected with a continuous single weld in each 3mm segments. It scores over excellent trackability and optimum radio-opacity. Therefore, it is easy to operate and feasible in tortuous, distal lesions and variety of lesion lengths. We report our experiences with Micro-II stent implanatation in the first 76 patients at Tonsei cardiovascular center to assess its safety and efficacy in patients with complex coronary anatomy and clinical results in the first months.

Between January 1996 and July 1996, eighty-six Micro-II stent were implanted in the coronary arteries of 76 patients(male 65.8%, age 59±10 year). Forty-five patients had unstable angina, the others had stable angina(17pts), acute myocardial infarction(14pts).

1) Indication of stenting was de novo 51(59.3%), suboptimal result 25(29.1%), restenosis 1(1.2%) and 9(10.4%) of lesions were stented in bail out situation. 2) Single stent were implanted in 76(88.4%)lesions, overlapping stent in 10(11.6%)lesions. Among overlapping stents, the second stent with Micro-II stent and with another kind of stent were 4.6%, 7.0%, respectively. 3) Procedure related complication including a subacute closure was occurred in 1(1.2%) patient who had distal dissection and 45% residual stenosis. In 12(14%) lesions, preistent dissection has been noticed after stent impantation. 4) Angiographic success(defined as a residual stenosis of <30% without major dissection) was achieved in 82 of 86 attempts(95.3%). The procedual success rate(defined as a residual stenosis of <30% without occurrence of major clinical events within 4 weeks after procesure) was 96.1%(73/76 patients). Angiographic success and procedural success rate in calcified lesion were 100% and 100%, respectively. Angiographic success and procedural success rate in more than 45` angulated lesion were 97% and 100%, respectively. 5) The mean minimal luminal diameter of the target lesions was increased from 0.42±0.40mm before stent implantation to 2.93±0.50mm(p<0.001). The percentage of diameter stenosis was reduced from 86.49±13.04% to 1.40±7.11%(p<0.001) after stent implantation.

Coronary stenting with AVE Micro-II stent can be safety performed and is particularly beneficial in tortuous and calcified arteries. There was a high tendency for peristent dissection which need to special consideration to avoid. Follow-up data is needed to assess mid and term patency. Coronary artery disease . AVE Micro-II stent . Immediate results.