The Valiant Captiva (Medtronic) thoracic stent graft has demonstrated positive outcomes at two years when used to treat acute complicated type B aortic dissections. Ali Azizzadeh, Memorial Herman Heart and Vascular Institute, Houston, USA, told delegates at the Vascular Interventional Advances (VIVA) meeting (2–5 November, Las Vegas, USA) that the stent graft was implanted with 100% delivery and deployment success and acceptable rates of adverse events. Session chairman, Michael R Jaff, Massachusetts General Hospital, Boston, USA, called the results “breath-taking”.
The most common aortic emergency, aortic dissection occurs in 4–5/100,000 people annually. Open surgical repair for acute complicated type B aortic dissection carries high morbidity and mortality rates, which can rise as high as 50–80% if complicated by renal or mesenteric ischaemia.
Therapy for the condition aims to stabilise the aorta and promote remodelling. In recent years, thoracic endovascular aortic repair (TEVAR) has allowed surgeons to reduce early morbidity and mortality when compared with open repair, and the procedure has thus become a first-line therapy.
The Valiant Captiva—approved by the US Food and Drug Administration for treating type B aortic dissections in January 2014—trial enrolled 50 patients at 16 US centres to evaluate the stent graft’s performance over five years. Eighty per cent of the patients were male and the average age was 57.2 years. Sixty-two per cent were Caucasian, 22% were African American and 12% were Asian.
Azizzadeh told delegates that 90% of patients had a history of cardiac illness, with 90% suffering from hypertension. At onset, 88% of patients exhibited back or chest pain, rupture was present in 20% and malperfusion in 86%.
The clinical trial investigators achieved 100% delivery and deployment success with the primary entry tear covered in all patients. No misaligned deployment was reported.
Two-year freedom from all-cause mortality was 81.8%. Only one death—adjudicated to natural causes—was reported between one and two years. Two-year freedom from dissection-related mortality was 90%. One dissection-related death was reported between 30 days and two years, which was a result of pneumonia. The 90% freedom from dissection-related mortality “suggests that after TEVAR the aorta stabilises, and these patients are dying from non-aortic-related events,” explained Azizzadeh.
Azizzadeh and colleagues reported “acceptable rates of adverse and serious adverse events,” with no serious adverse events between one and two years after intervention. Two serious adverse events—one retrograde type A aortic dissection and one acute renal failure—occurred between 30 days and one year. Four patients required secondary endovascular procedures within two years of surgery. Three of these procedures were dissection-related (extension endografts) and the fourth was an implantation of a left subclavian plug placement for endoleak, which was not related to dissection.
The patient population also enjoyed “favourable remodelling over the stented segment,” according to Azizzadeh. Of all the patients, 71.4% had dissection extending to or past the aortic bifurcation. Among these, 42% had more than one visible re-entry tear and 28% had three or more re-entry tears. At two years, the maximum diameter of false lumen had decreased or was stable in 78.6% of patients. In comparison, the maximum diameter of true lumen had increased or remained stable in 85.7% of patients and partial or complete false lumen thrombosis was observed in 70.4% of patients at two years.
“These mid-term results of the Valiant Captiva thoracic stent graft system in the treatment of acute complicated type B aortic dissection are very encouraging,” concluded Azizzadeh. “Long-term outcomes are needed to assess the durability of TEVAR for this indication.”