NEW YORK – A significantly higher percentage of patients achieved false lumen thrombosis in the best medical therapy plus stent group, compared with those who received only BMT, based on 1-year results of the ADSORB trial.
The maximum true lumen diameter at 1 year was also greater in those who received the combination treatment, Dr. G. Chad Hughes of Duke University Medical Center, Durham, N.C., said at the meeting sponsored by the American Association for Thoracic Surgery.
The ADSORB trial is a European study sponsored by W.L. Gore and Associates and is the first-ever randomized trial comparing BMT with BMT plus stent grafting of the proximal tear in patients having an uncomplicated type B acute dissection of the descending aorta. The stent used was the Gore TAG Endoprosthesis (TAG). BMT consisted of a regimen of antihypertensive medications used to maintain blood pressure below 125/80 mm/Hg throughout the entire follow-up period. The regimen was individualized to each patient, but typically consisted of one to four concomitant antihypertensive medications.
The final study cohort was comprised of 30 patients with acute uncomplicated type B dissection of the descending aorta who received TAG + BMT and 31 who received BMT alone. All were randomized within 5 days of symptom onset. For inclusion in the study, patients could not have a descending thoracic aortic aneurysm or a transverse diameter of the descending thoracic aorta of 55 mm or greater.
The primary endpoint consisted of three components. For the first component, the percentage of patients achieving false lumen thrombosis in the TAG + BMT group was statistically higher than in the group who received BMT alone (P less than .001). Complete thrombosis was seen in 63.3% of those receiving combination treatment vs. 6.5% of the BMT-alone group, while a much higher rate of no or incomplete thrombosis was found in the BMT group (67.7% vs. 13.3%). About one-quarter of each group were considered failures because of incomplete imaging.
The second component, which evaluated aortic dilatation, showed no significant differences. For instance, 70% of the TAG + BMT group showed no dilatation, compared with 61.3% of the BMT-alone group; the rates of dilatation were 22.6% in the BMT group vs. 6.7% in the combination treatment group (P = .474).
One-year aortic rupture was the third component of the primary endpoint, and no differences were apparent between groups. There were no aortic ruptures within 365 days of randomization in either of the treatment groups, with excellent survival seen in both groups at 1 year.
When all three components were taken into consideration, 56.7% of those treated with TAG + BMT were free from all of the endpoint events, compared with 3.2% of the BMT group, and this difference was significant (P less than .001).
The secondary endpoint related to evidence of aortic remodeling at 1 year. The study found that the maximum true lumen diameter was significantly larger in the BMT + TAG group (P less than .001). A nonsignificant trend was seen toward smaller overall aortic diameter in the TAG + BMT group (P = .06)
Dr. Hughes addressed some of the criticisms of the ADSORB trial. For instance, it has been suggested that the surrogate composite endpoint does not yield clinically useful information that can be applied to make treatment decisions. Dr. Hughes explained that the study was conceived as a feasibility study rather than one designed to give definitive advice about treatment. He also acknowledged that the small sample size was underpowered to detect differences in aortic-related or all-cause mortality. Objections have also been raised that the definitions of false lumen thrombosis differed for the two groups, and might have favored the TAG + BMT group.
Dr. Hughes did not participate in the ADSORB trial but said he does have a financial relationship with W.G. Gore and Associates, the study sponsor. He presented the results on behalf of the principal investigator, Dr. Jan Brunkwall of the University of Cologne (Germany).