Optical coherence tomography for DES SAfety - ODESSA
Animal and autopsy studies of drug-eluting stents (DES) have demonstrated delayed healing and incomplete endothelialization at sites of DES overlap. It is unknown if the use of overlapping DES is associated with a higher incidence of incomplete or delayed stent coverage in humans. The ODESSA trial was designed to assess the utility of optical coherence tomography (OCT) in evaluating strut coverage and malapposition of different DES compared with bare-metal stents at a micron level in vivo.
OCT would allow accurate characterization of strut coverage and malapposition in long lesions (>20 mm) requiring overlapping stents.
Patients Enrolled: 77
Mean Follow Up: 6 months
Mean Patient Age: 66.5 years
Long lesions (>20 mm) requiring overlapping stents
Proportion of stent struts uncovered and/or malapposed at overlap in OCT at 6 months
- Percent intimal hyperplasia by OCT and IVUS at 6 months
- Six-month clinical outcomes, including death, myocardial infarction, stent thrombosis, and need for repeat revascularization
OCT was used to characterize patients with sirolimus-eluting (SES), paclitaxel-eluting (PES), zotarolimus-eluting (ZES), and bare-metal stents (BMS).
Dual antiplatelet therapy
A total of 77 patients (189 stents) were randomized, of which 22 received Taxus (PES), 22 received Cypher (SES), 22 received Endeavor (ZES), and 11 received Liberte (BMS). Lesion characteristics, including reference vessel diameter (2.78 mm), lesion length (35.9 mm), % stenosis (76.4%), and minimal luminal diameter (0.64 mm) were similar between the four arms. The left anterior descending artery was the target vessel in 61% of all cases. The mean number of stents per lesion was 2.4, with an average stent diameter of 2.93 mm. Stent overlap was necessary in 39% of the patients. OCT was used to quantitatively analyze 250 stented segments, 6,968 cross-sections, and 53,047 struts.
The proportion of uncovered and/or malapposed struts when stents were overlapped tended to be higher with DES compared with BMS, although this difference was not statistically significant (5.4% vs. 1.8%, p = 0.08). On further analysis, the proportion of uncovered and/or malapposed struts was highest with SES (8.7%), followed by PES (8.3%), and then ZES (0.05%) (p < 0.05 for all comparisons). When DES were not overlapped, the incidence of malapposed or uncovered struts was still highest with SES (7.9%), followed by PES (2.3%) and then ZES (0.01%), compared with BMS (0.5%) (p < 0.05 for all comparisons). There seemed to be an inverse relationship between uncovered and/or malapposed struts and intimal hyperplasia: % intimal hyperplasia was 19.3% versus 31.5% versus 45.2% versus 57.8% for SES, PES, ZES, and BMS, respectively (p < 0.05), as measured with OCT. There was also a high correlation between OCT and intravascular ultrasound (IVUS) findings for intimal hyperplasia, although OCT demonstrated intimal hyperplasia more often than IVUS.
The incidence of in-hospital adverse events was very low, with no difference between the four groups. On 6-month follow-up, there was only one death, which occurred in the SES group due to probable stent thrombosis. The incidence of repeat revascularization was lowest in the SES group, but it was not statistically significant (4.5% vs. 9.1% vs. 13.6% vs. 36.4%, p = 0.07).
The ODESSA trial demonstrates the utility of OCT in studying strut coverage and malapposition in vivo. The proportion of uncovered and/or malapposed struts tended to be higher with DES compared with BMS in both overlapping and non-overlapping situations. Of all the DES, SES seemed to be associated with the highest incidence of uncovered and/or malapposed struts, whereas ZES had a virtually zero incidence of the same. On the other hand, SES seemed to be associated with a trend toward a lower incidence of intimal hyperplasia and repeat revascularization, compared with both PES and ZES, as well as BMS. Clinical events were low, and similar between the four stent groups.
While the OCT findings are unique and interesting, the clinical significance of these findings is unclear. Moreover, even in this small study, the investigators had to analyze more than 50,000 struts. Hence, until this methodology is standardized, automated, and validated, its applicability in routine practice is limited.
Guagliumi G, Musumeci G, Sirbu V, et al. Optical coherence tomography assessment of in vivo vascular response after implantation of overlapping bare-metal and drug-eluting stents. JACC Cardiovasc Interv. 2010 May;3(5):531-9
Presented by Dr. Giulio Guagliumi at the Transcatheter Cardiovascular Therapeutics meeting (TCT 2008), Washington, DC, October 2008.
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