Two-year results from STABLE trial unveiled



SAN FRANCISCO – Endovascular repair of complicated type B aortic dissection using a composite device design demonstrates favorable aortic modeling, 2-year results from an ongoing trial showed.

However, patients treated in an acute phase may be prone to aortic growth and require close monitoring, Dr. Joseph V. Lombardi reported at Society for Vascular Surgery Annual Meeting.

Those are key findings the STABLE trial, a prospective, multicenter trial evaluating the safety and effectiveness of a composite endovascular system consisting of TX2 thoracic stent grafts and distal bare metal dissection stents (Zenith Dissection Endovascular System; Cook Medical) for the treatment of complicated type B aortic dissection. The system is commercially available in Europe but not in the United States.

Dr. Joseph Lombardi

The first published results from STABLE, which was comprised of 40 patients, found a 30-day mortality of 5% and a 1-year all-cause mortality of 10% (J. Vasc. Surg. 2012;55:629-40) "Positive aortic modeling was recognized as well," said Dr. Lombardi, chief of vascular surgery at Cooper University Hospital in Camden, N.J., and the principal STABLE investigator. "The goals for complicated type B aortic dissection are to recognize complications promptly, alleviate branch vessel malperfusion, reduce the risk of rupture, and minimize long-term complications."

Dr. Lombardi updated meeting attendees on 2-year data from the STABLE trial, which is being conducted in the United States, Europe, and Australia. He reported on results from 86 patients with a mean age of 59 years. Nearly three-quarters (73%) were male. The primary endpoint is 30-day mortality and follow-up through 5 years is ongoing.

The researchers observed a mean onset to treatment of 17 days. More than half (64%) presented in an acute phase, which they defined as within 0-14 days of symptom onset, while the remainder presented in a non-acute phase defined as greater than 14 days after symptom onset.

"The anatomical extent of the dissections extended through the visceral aorta in 99% of cases and in the common iliac artery or below in 80% of cases," Dr. Lombardi said. "There were a number of device combinations used depending on the patient’s anatomical presentation. Successful device deployment was seen in all patients, with 100% patency."

The all-cause mortality was 12% at 1 year and 15% at 2 years. The 30-day mortality rate for the 86 patients was 4.7%. Of the 55 patients who had acute presentations, the 30-day mortality rate was 5.5%.

"There were nine deaths between 1 month and 24 months, four of which were determined to be not related to the dissection," he said. "Combined, this translated into a dissection-related mortality of 11% at 24 months."

Between baseline and 2 years the true lumen diameter increased significantly in the descending thoracic aorta and in the more distal abdominal aorta, with a concomitant decrease in false lumen diameter, Dr. Lombardi said. Transaortic growth of 5 mm or greater was observed in the descending thoracic aorta in 21 patients (24%) and the abdominal aorta in 21 patients (24%).

Generalized linear model analysis revealed that the only significant factor for transaortic growth was duration from symptom onset to treatment (P = .05). "The acute phase treatment is associated with a risk of aortic dilation," Dr. Lombardi said. "Patients in this subgroup need to be closely monitored. Longer-term follow-up on STABLE is needed."

The STABLE Trial was sponsored by Cook Medical. Dr. Lombardi disclosed that he has received research grants from Cook Medical.

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