DOES STANDARD SURGICAL REPAIR OF DEBAKEY TYPE I DISSECTION ALTER TRUE LUMEN GEOMETRY DOWNSTREAM?

Abstract

After successful surgical repair of DeBakey Type I dissection using contemporary standard surgical techniques, patients are generally left with a dissection flap in the descending aorta. Recent evidence suggests that a narrowed true lumen in the distal aorta may lead to early end-organ malperfusion if vital branch vessels arise off the narrowed true lumen. Furthermore, an effaced true lumen may also be associated with poor long term outcomes. The effect of standard surgery involving cardiopulmonary bypass, replacement of the ascending aorta and an open distal anastamosis on the true lumen size in the distal aorta has not been investigated. Pre- and post-op CT scans of patients who had emergency repair for acute aortic syndrome at a single centre between 2006 and 2013 were reviewed. Patients with Debakey Type 2 Dissection, intramural hematoma, hybrid arch repair, total arch repair, and those patients that did not have adequate imaging were excluded. Using a TeraRecon workstation, double oblique surface area measurements of the true lumen and total aortic lumen at the level of the subclavian artery, pulmonary artery bifurcation and diaphragmatic hiatus were obtained. A total of 128 patients underwent operative repair. Inclusion criteria were met by 45 patients (34 males and 11 females) with a mean age of 56 (range 26-79). The median interval between scans was 11 days. The average pre-op and post-op true lumen area in the descending aorta was 2.43 cm2 (0.98-4.25) and 2.70 cm2 (0.82-4.90) respectively. Preoperatively, the true lumen constituted 36% of the total aortic area in the descending thoracic aorta. Postoperatively, this ratio was 38% (p=NS). The true:total ratio improved in 44% of the study population and worsened in 56%. In the group that showed improvement, the average increase in true:total aortic ratio was 42% (median 35%, range: 3%- 121%). In the group that showed worsening of the average ratio, the average decrease was 18%(median 17%, range 49% - 2%). Standard surgical repair in patients with acute De Bakey type I dissection may not improve true lumen morphology in the descending thoracic aorta. When malperfusion is clinically suspected perioperatively and the true lumen is effaced, consideration should be given to adjunctive modalities that may expand true lumen area. Further research is required to understand if adjunctive surgical strategies to expand the true lumen distally will mitigate long term complications.