Endovascular Treatment for Chronic Type B Dissection:Limitations of Short Stent-Grafts Revealed at Midterm Follow-up

Abstract

To examine the incidence of and the indications for re-intervention, as well as the changes in aortic morphology, in patients with chronic type B aortic dissection who underwent endovascular intervention for false lumen aneurysms. A retrospective analysis was conducted of 10 patients (8 men; mean age 63 years, range 45-79) who underwent stent-graft repair of aneurysmal false lumen expansion related to chronic type B aortic dissection at a median 16 months (range 2-71) from the initial diagnosis. All grafts had been oversized by 10% relative to the normal non-dissected aorta and were implanted to cover the primary entry tear. Follow-up computed tomography scans were analyzed to define changes in aortic morphology. Mean radiological follow-up was 56 months (median 64.5; range 19-86.5). There was no perioperative mortality or stroke; no cases of aortic rupture were recorded during follow-up. One patient suffered a procedure-related stroke with postoperative hemiparesis following re-intervention for proximal erosion 15 months after the initial treatment. In 6 of the 7 re-interventions performed in 6 patients at a median 42 months after the index procedure, stent-graft extension was required to treat erosion of the dissection membrane that had resulted in endoleak with false lumen reperfusion. The extent of dissection, duration of follow-up, or length of aortic coverage was not predictive of the need for re-intervention during follow-up. At last follow-up, the mean false lumen diameter at the level of the stented aorta was significantly smaller than at baseline (11+/-15 versus 24+/-15 mm, p<0.01). This was associated with false lumen thrombosis at the level of the stent-graft in 9 of 10 cases, although 7 patients had persistent false lumen perfusion distal to the stent-graft. Endovascular stent-graft treatment is effective therapy for chronic type B dissection patients with false lumen aneurysms. Erosion of the dissection membrane, causing proximal or distal endoleak, is the most common reason for re-intervention during midterm follow-up.