Managing Branch Vessels in Acute Dissections

During Tuesday’s session on Aortic Updates, Dr. John Fritz Angle of the University of Virginia in Charlottesville provided an overview on managing branch vessels in acute dissections. Dissections can extend into the branch, causing malperfusion, and aortic intima can separate from a branch completely, making the branch dependent on false lumen flow. Malperfusion (brachiocephalic, spinal, renal, mesenteric, or lower extremity) is common, he said, with an incidence of 30% and early mortality of 30%.

After examination and computed angiography, Dr. Angle indicated that angiography, intravascular ultrasound, and pressure measurements are essential in determining which patients to treat; management options for these patients include conservative treatment, operative bypass, or endovascular stents. Discussing when to treat, he said that branch occlusions should be managed after potential bleeding is under control (eg, type A repair) and closure of entry tear (type B endograft). Treatment of most hypoperfused branches is deferred unless definite clinical signs are seen.

Treatment of aortic branch dissections can be performed with stents in most situations, he said. Self-expanding covered stents extend the dissection and stent migration; using covered stents seals fenestrations to exclude false lumen flow. Bare-metal self-expanding stents can be used to protect distal renal or superior mesenteric branches. Balloon-expandable covered stents may be required in some cases, such as after placement of an abdominal aortic stent due to aortic stent struts encroaching on the ostea).

Dr. Angle reviewed a study by Cirillo-Penn et al regarding 34 patients who underwent retrograde open stenting; 18 (53%) were treated for acute mesenteric ischemia (AMI), 11 (32%) for acute-on-chronic mesenteric ischemia, and 5 (15%) for chronic mesenteric ischemia. Etiology was chronic atherosclerosis in 28 (82%), superior mesenteric artery dissection in 3, and 3 other causes. Technical success was seen in 31 patients (91%); 8 (23%) required thromboembolectomy and 9 (26%) underwent patch angioplasty. Thirty-day mortality rate was 35%, all in patients with AMI (10) or acute-on-chronic mesenteric ischemia (2). Eighteen patients (53%) underwent bowel resection.

In conclusion, Dr. Angle indicated that aggressive early management of branch dissections is warranted, given its high morbidity and mortality. Clinicians should stent to a normal caliber distal true lumen and proximally to the aortic true lumen, and in general use covered stents unless critical branches are to be covered. IVUS is important both pre- and post-treatment.