Spinal Cord Ischemia and Reinterventions Following thoracic endovascular repair for Acute Type B Aortic Dissections

Objective The technical aspects of thoracic endovascular aortic repair (TEVAR) for acute type B aortic dissection (TBAD), specifically the location of proximal seal zone (PSZ) (need to cover the left subclavian artery [LSA]), distal seal zone (DSZ) (length of aortic coverage), benefit of LSA revascularization, and prophylactic lumbar drainage are still debated. Each of these issues has potential benefits but also has known risks. This study aims to identify factors associated with reintervention and spinal cord ischemia (SCI) following TEVAR for acute TBAD with a zone 3 entry tear. Methods The Vascular Quality Initiative was queried for TEVARs performed for acute TBAD with zone 3 entry tear, zone 3 proximal zone of disease, treated with TEVAR extending between zone 2 and zone 5. The primary outcomes were SCI and related reintervention. Secondary outcomes were stroke, arm ischemia and retrograde type A dissection (RTAD). The exposure variables were PSZ 2 vs. 3, DSZ 4 vs. 5, prophylactic lumbar drain, and LSA revascularization. Univariate analyses were conducted with chi-square analysis and multivariable logistic regression was used to evaluate association with outcomes. Results Of 583 patients who met inclusion criteria, 266 had PSZ 2 and 317 had PSZ 3. On univariate analysis, PSZ 2 was associated with a higher rate of reintervention, but PSZ2 was not significant on multivariable analysis after accounting for age, sex, race, smoking, PSZ, DSZ, prophylactic lumbar drain and LSA patency. PSZ 2 was not associated with SCI, arm ischemia, or RTAD. PSZ 2 was associated with a trend towards a higher rate of stroke. DSZ 4 and DSZ 5 were performed in 161 and 422 TEVARs, respectively, and DSZ 5 was associated with a higher rate of SCI on univariate (3 [1.9%] vs. 39 [9.2%], P = .01) and multivariable (OR, 7.384, [95% CI, 2.193 – 24.867]; P = .001) analyses. Prophylactic lumbar drain placement was not statistically significantly associated with SCI, but lack of postoperative LSA patency was associated with SCI (OR 2.966, [95% CI, 1.016 – 8.656]; P = .05). Conclusions This study found that PSZ 2 was not associated with lower reinterventions or higher rates of SCI but trended towards a higher rate of stroke than PSZ 3. Additionally, DSZ 5 was strongly associated with SCI when compared with DSZ 4, highlighting the importance of limiting aortic coverage to coverage of the proximal entry tear when possible.