Initial Results after Implantation of Coronary Artery Stents with Antiplatelet Agents

Son, Ji Won; Kim, Yeong Jun; Son, Min Soo; Oh, Se Jin; Ahn, Tae Hoon; Choi, In Suk; Shin, Iak Kyun

Abstract

Backgound: The placement of stents in coronary arteries has been shown to reduce acute closure and restenosis in comparison to balloon angioplasty. However, clinical use of intracoronary stents is impeded by the subacute stent thrombosis and hemorrhagic complications associated with the anticoagulant regimen. It's known that the complete stent deployment with high pressure inflation and new antiplatelet agents are effective in reduction of subacute thrombosis and hemorrhage. So we evaluated initial results (success and complication rate) after high pressure-stent deployment with new anticoagulation protocol.
METHODS
One hundred and ninety one patients with 201 lesions were treated with 231 stents of various types. The high pressure balloon inflation and antiplatelets agents were used in all cases. Final high pressure balloon inflation guided by IVUS were performed in 23 consecutive cases with incomplete stent deployment according to angiographic findings.
RESULTS
1) The indications of stenting (n=210) were De novo in 124 (59%), bailout procedure in 57 (27%), suboptimal result after PTCA in 19 (8%), and restenosis after PTCA in 14 (6%). The location of lesions were LAD in 101, RCA in 67, circumflex in 28, ramus intermedius in 3, and LMT artery in 2 lesions. Angiographic morphologic characteristics were type A in 2, type B in 158 (B1: 57, B2: 101), and type C in 22 lesions. 2) The angiographic and clinical success rate was 96% (192/201) and 92% (186/201) respectively. 3) In angiographic analysis, the baseline average reference vessel dirmeter was 3.33+/-0.35 mm. Baseline minimum lumen diameter (MLD) was 0.58+/-0.29 mm, with baseline percent diameter stenosis of 82.86+/-8.64%. The final stent diameter was 3.37+/-0.29 mm, with mean final percent stenosis of 0.63+/-8.25. The mean MLD after stenting was significantly increased (p<0.001). The mean MLD within stent increased 14%, from 2.91+/-0.39 mm at the nominal balloon inflation (inflation pressure=7 atm) to 3.37+/-0.29 mm at high pressure balloon inflation (inflation pressure <0A65B>12atm) (p<0.001). The length of lesions in GR I (cook), GR II, and Micro II stents were significantly longer than ones in PS, Cordis, Wiktor, Nir (p<0.001). 4) In intravascular ultrasound analysis, the mean lumen CSA at the tightest point within stent increased 11%, from 8.4+/-2.4 mm2 at the intial intravascular ultrasound to 9.4+/-2.1 mm2 at the final intravascular ultrasound (p<0.001). 5) The procedural and postprocedural complications were 2 acute closures associated with AMI and emergent CABG, 1 subacute closure which was revascularized by bail out stenting, 5 major hemorrhage requiring transfusion associated with 1 CVA and 2 metabolic acidosis induced by acute renal failure, and 5 death.
CONCLUSION
The high pressure stent deployment procedure and new anticoagulation protocol associating tidopidine and aspirin without coumadin or prolonged heparin infusion allow us to obtain an acceptably low subacute thrombosis or bleeding complication rate. These results are encouraging and allow a wide use of coronary stenting.