Abstract 2832: Intravascular Ultrasound Evaluation of Optimal Stent Expansion: Cypher versus TAXUS Stent. Post-stent Optimal Stent Expansion Trial (POET)
Background: The aim of this study is to compare two different drug-eluting stents, Cypher and TAXUS stents in their property to expand adequately by staged balloon inflation.
Methods: We conducted a prospective multicenter, randomized study to compare Cypher(groupI, n=104) vs TAXUS stent(groupII, n=106) in IVUS parameters regarding stent expansion and clinical outcomes. A total of 210 patients (M:F = 127:83, age 61.8±8.8 years), who underwent the elective coronary stenting for a de-novo lesion were included. Infarct-related lesions within 7 days were excluded. Stent was serially expanded with gradual increase in balloon inflation pressures (1. stenting with nominal pressure; 2. adjuvant ballooning up to 14 atm; 3. up to 20 atm) until optimal stent expansion (OSE) criteria were met. Adjuvant balloon dilation was performed using a non- or semi-compliant balloon. OSE was defined as the criteria of MUSIC study. IVUS was performed before and after each balloon inflation. The presence of OSE and various IVUS parameters were investigated after each post-stent adjuvant balloon inflation step.
Result: Baseline clinical, lesion, balloon catheter and stent characteristics of both groups showed no significant difference. After stenting with the nominal pressure of the stent balloon, OSE was found in 5 (4.8%) of group I and 5 (4.7%) of group II (p=NS). After 1st and 2nd post-stent adjuvant balloon dilations, OSE was obtained in 6 (5.8%) and 24 (23%) of group I and in 12 (11.3%) and 18 (17.0%) of group II (p=NS). The ratio of final minimal stent area (MSA) to reference area, an indicator for the extent of final stent expansion were not different between the two groups (Cypher 80.8±12.6% vs TAXUS 82.7±13.8%, p=NS). However, the initial ratio of MSA to reference area, after nominal pressure ballooning were different between two stents (Cypher 58.9±13.0% vs TAXUS 67.9±14.8%, p<0.001).
Conclusion: The stent underexpansion was found commonly after stent deployment at nominal pressure and the ratio of MSA to reference area was lower in Cypher than TAXUS. Both stents revealed no statistical difference in the incidence of OSE and the extent of stent expansion after high pressure balloon inflation. The significance of OSE in DES will to be evaluated by follow-up angiography and IVUS study.