Thoracic Endovascular Aortic Repair for Type B Dissection

A more proximal landing zone is preferred for thoracic endovascular repair of acute type B aortic dissections

OBJECTIVES

Thoracic endovascular aortic repair (TEVAR) has become first line therapy for complicated acute type B aortic dissection (aTBAD). However, the strategy for optimal proximal landing zone remains to be determined. We compared early outcomes and late aortic-related adverse events in patients undergoing TEVAR for complicated aTBAD with endograft deployment in proximal landing zone 2 versus 3.

METHODS

We performed a retrospective chart review of adult patients undergoing TEVAR for complicated aTBAD within 6 weeks of diagnosis from 1/2008 to 12/2018. We excluded patients with connective tissue disorders and prior type A repair. Patients were divided into landing zone 2 TEVAR (Z2T) and zone 3 TEVAR (Z3T) groups. Z2 patients were divided between left subclavian artery (LSA) revascularization (Z2R) versus LSA coverage without revascularization (Z2C). Groups were compared for need for aortic re-intervention within 36 months of initial admission and freedom from aortic related adverse events and mortality (AREM), defined as need for aortic re-intervention, aortic-related death or rupture.

RESULTS

Eighty-three patients underwent TEVAR for complicated aTBAD within a mean of 4.1±7.8 days. 89.5% of patients had less than 2 cm of healthy proximal descending thoracic aorta. Landing zone was Z3T in 35 patients and 48 underwent Z2T: 10 Z2C and 38 Z2R. There were no differences between Z2T and Z3T in time from diagnosis to TEVAR, demographics, comorbidities and diameter aortic measurements. 30-day survival was 87.8%: 89.5% for Z2R, 88.6% for Z3 and 80.0 % for Z2C (p=0.610). Post-operative spinal cord ischemia rate was 3.7%: 2.7 % for Z2R, 0% for Z3T and 20.0% for Z2C (p=0.012). Post-operative thoracic aortic rupture was 2.2% in Z2 and 0 in Z3. Need for aortic re-intervention at 36 months post-TEVAR was lower for Z2T (10.4%) vs. Z3T (31.4%), p=0.025. Freedom from AREM at 36 months was higher in Z2T vs. Z3T - 87.5% vs. 68.6%, p= 0.048. Freedom from proximal re-intervention was higher in Z2T (95.8%) compared to Z3T (80.0%), p=0.019. Z3T deployment was predictive for AREM (OR:3.648,95%CI:1.161-11.465,p=0.027) and need for proximal re-intervention (OR: 5.542,95%CI:1.062-28.927,p=0.042).

CONCLUSION

Most patients with aTBAD have less than 2 cm of proximal healthy descending thoracic aorta. In patients treated for complicated aTBAD, zone 2 TEVAR is associated with a lower need for aortic re-intervention and aortic-related adverse events than zone 3 TEVAR. Patients may benefit from a more aggressive proximal landing zone with similar perioperative morbidity when zone 2 TEVAR is done with LSA revascularization.

Acute aortic syndromes: diagnosis and management, an update

Acute aortic syndromes (AAS) encompass a constellation of life-threatening medical conditions including classic acute aortic dissection (AAD), intramural haematoma, and penetrating atherosclerotic aortic ulcer. Given the non-specific symptoms and physical signs, a high clinical index of suspicion is necessary to detect the disease before irreversible lethal complications occur. In order to reduce the diagnostic time delay, a comprehensive flowchart for decision-making based on pre-test sensitivity of AAS has been designed by the European Society of Cardiology guidelines on aortic diseases and should be thus applied in the emergency scenario. When the definitive diagnosis is made, prompt and appropriate therapeutic interventions should be undertaken if indicated by a highly specialized aortic team. Urgent surgery for AAD involving the ascending aorta (Type A) and medical therapy alone for AAD not involving the ascending aorta (Type B) are typically recommended. In complicated Type B AAD, thoracic endovascular aortic repair (TEVAR) is generally indicated. On the other hand, in uncomplicated Type B AAD, pre-emptive TEVAR rather than medical therapy alone to prevent late complications, while intuitive, requires further study in randomized cohorts. Finally, it should be highlighted that there is an urgent need to increase awareness of AAS worldwide, including dedicated education/prevention programmes, and to improve diagnostic and therapeutic strategies, outcomes, and lifelong surveillance.