VALOR II and VALOR Results Published for Medtronic's TEVAR Devices

October 23, 2012—In the Journal of Vascular Surgery, Ronald M. Fairman, MD, et al report 30-day and 12-month results from the VALOR II study of endovascular treatment with the Valiant thoracic stent graft system (Medtronic, Inc., Minneapolis, MN) in patients with descending thoracic aortic aneurysms of degenerative etiology (2012;56:1222–1231). The Valiant stent graft is an evolution of Medtronic's Talent thoracic stent graft, noted the investigators.

Also in the Journal of Vascular Surgery, Paul J. Foley, MD, et al published the 5-year results of the VALOR trial of thoracic endovascular aneurysm repair (TEVAR) of the Talent thoracic stent graft in patients considered low or moderate risk for open surgical repair (2012;56:1214–1221).

In the published VALOR II study, the investigators stated that the prospective, nonrandomized, pivotal trial was conducted at 24 sites in the United States with enrollment between December 2006 and September 2009. Standard follow-up examinations, including physical examination, computed tomography, and chest radiography, were performed at 1, 6, and 12 months, and annually through 5 years. VALOR II outcomes were compared with those from the pivotal VALOR trial of the Talent stent graft, which enrolled 195 patients with similar enrollment criteria.

As summarized in the Journal of Vascular Surgery, VALOR II enrolled 160 patients. Compared with VALOR patients, VALOR II patients had similar age and sex distribution but higher rates of cardiovascular risk factors and significantly more severe modified Society for Vascular Surgery/American Association for Vascular Surgery risk scores. Stent graft delivery and deployment were successful in 154 patients (96.3%).

Outcomes at 30 days in VALOR II were perioperative mortality, 3.1%; major adverse events, 38.1%; paraplegia, 0.6%; paraparesis, 1.9%; and stroke, 2.5%.

At 12 months, after the minimum sample size was reached, 151 patients were evaluated. Aneurysm-related mortality was 4%, stent graft migration was 2.9%, and endoleak was 13%. Through 12 months, there were no ruptures, conversions to open surgery, secondary procedures due to endoleak > 30 days, or loss of stent graft patency. The Valiant stent graft was statistically noninferior to the Talent stent graft in 12-month all-cause mortality (12.6% vs 16.1%) and exceeded the primary effectiveness goal of 12-month successful aneurysm treatment, defined as absence of aneurysm growth > 5 mm and absence of secondary procedures for type I/III endoleak (97.4% vs 80%).

The investigators concluded that the VALOR II 12-month results demonstrate that the Medtronic Valiant thoracic stent graft is a safe and effective treatment for patients with descending thoracic aortic aneurysms of degenerative etiology.

In the VALOR study of the Talent device in patients considered at low or moderate risk for open surgical repair, the investigators conducted a prospective, nonrandomized, multicenter, pivotal study at 38 sites in the United States. Between December 2003 and June 2005, VALOR enrolled 195 patients who were low or moderate risk (0, 1, and 2) per the modified Society for Vascular Surgery and American Association for Vascular Surgery criteria. The patients had fusiform thoracic aortic aneurysms (TAAs) and/or focal saccular TAAs/penetrating atherosclerotic ulcers. Standard follow-up interval examinations were conducted at 1 month, 6 months, 1 year, and annually thereafter.

As summarized in the Journal of Vascular Surgery, during the 5-year follow-up, 76 deaths occurred (43.9%). Freedom from all-cause mortality was 83.9% at 1 year and 58.5% at 5 years. Most deaths were due to cardiac, pulmonary, or cancer-related causes. Freedom from aneurysm-related mortality (ARM) was 96.9% at 1 year and 96.1% at 5 years. There was 1 case of ARM after the first year of follow-up.

During the 5-year follow-up period, four patients were converted to open surgery and four patients experienced aneurysm rupture. The 5-year freedom from aneurysm rupture was 97.1% and the 5-year freedom from conversion to surgery was 97.1%. The incidence of stent graft migration (> 10 mm) was ≤ 1.8% in each year of follow-up. The rate of type I endoleak was 4.6% at 1 month, 6.3% from 1 month to 1 year, and 3.8% during year 5. The rate of type III endoleak was 1.3% at 1 month, 1.9% from 1 month to 1 year, and 1.9% during year 5. Through 5 years, 28 patients (14.4%) underwent 31 additional endovascular procedures on the original target lesion. The 5-year freedom from secondary endovascular procedures was 81.5%, reported the VALOR investigators.

The VALOR investigators concluded that through 5-year follow-up in patients who were candidates for open surgical repair, TEVAR using the Talent thoracic stent graft system has demonstrated sustained protection from ARM, aneurysm rupture, and conversion to surgery, and durable stent graft performance. Close patient follow-up remains essential after TEVAR, the investigators advised.