Selective Direct Coronary Stenting In Unstable Coronary Syndrome

Objective To evaluate the feasibility and safety of stenting without balloon predilatation in elective coronary artery lesions and further explore its effect on coronary artery microcirculation so as to strengthen the clinical significance of coronary artery microthrombus.Methods From Jan.2001 to Dec. 2002, 92 patients withunstable coronary artery syndrome were selected and divided into direct stent implantation group A(n=39) and stent implantation with predilatation group B(n=53). Only lesion type A or Bl without any calcification and important angulation were treated with only one stent and the lesion had to be <10mm in length with a coronary artery diameter >2.5mm. 6 hours before and after operation, cTnT was tested . After successful angioplasty, patients continued with aspirin 150mg daily and received ticlopidine 250mg twice daily for 6 weeks.Results In group A in 38(97%) of the 39 cases the stents easily crossed the lesions and could be expanded with high balloon pressures (12-16atm). In group B in 52(98%)of the 53 cases the stents successfully crossed the lesions. In group A, the mean time of the procedure and fluoroscopy were respectively 21±11 minutes and 9±6 minutes. The volume of contrast was 138±55ml,obviously lower than that of group B(58±4min,p<0.001; 33±4min, p<0.001; 180±36ml, p<0.001). In group A in 8(21%)of the 38 cases, blood circulation in lesion blood vessel became slow but turned normal after injecting 500ug verapamil, indicating temporary "no-reflow phenomenon". Of the 38 cases in group A: TMPO: 0 case; TMP1: 0 case; TMP2: 3 cases and all the rest 35 cases TMP 3. In group B 12 cases had temporary "no-reflow phenomenon". TMPO: 5 cases; TMP1: 3 cases; TMP2; 6 cases, and all the rest 39 cases TMP3. There is marked difference between the two groups. In group A cTnT after operation>0.1ng/ml: 3 cases(7.9%); in group BcTnT>0,Ing/ml: 18 cases(33.9%),There is a marked difference between the two groups(p<0.001). In 14 Of the 18 cases are below TMP3 showing thrombosis in coronary artery microcirculation. During the hospitalization, no subacute occlusion, acute myocardial infarction and death or coronary artery bypass graft surgery occurred. A half-year follow-up showed that in group A 5 cases had angina with contrast medium indicating coronary restenosis (13%); in group B 18 cases had angina, with contrast medium indicating coronary restenosis(22.6%);one case died.Conclusion Direct stent implantation without predilitation is feasible and safe but should be selective with the advantages of shorter procedural time, shorter duration of vessel occlusion, shorter exposure to X-ray, smaller dose of contrast medium, lower incidence of coronary artery far-end thrombosis, higher myocardial perfusion grading, lower rate of blood vessel restenosis and lower rate of complication.