Commentary on ‘Distinction between Acute and Chronic Type B Aortic Dissection: Is there a Subacute Phase?’

A Systematic Review and Meta-Analysis of Current Evidence Related to the Impact of Endovascular Repair Timing on Prognosis of Acute Stanford Type B Aortic Dissection

BACKGROUND

The objective of this study was to determine whether thoracic endovascular aortic repair (TEVAR) timing is more beneficial in the acute phase (first 14 days) than in the subacute phase (14-90 days) for the administration of acute Stanford type B aortic dissection (TBAD).

METHODS

A comprehensive literature search was conducted in databases (EMBASE, PubMed and Cochrane Library) until December 2023 to identify studies reporting the results of TEVAR used for patients with acute TBAD. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated utilizing either the random-effects model or the fixed-effects model.

RESULTS

A total of 25 studies involving 4,827 individuals with TBAD (including 1,609 with subacute TBAD) met our selection criteria. Early results revealed a lower incidence of Ia endoleaks (OR, 1.55; 95% CI, 1.03-2.33; P = 0.04) and aortic ruptures (OR, 2.89; 95% CI, 0.98-8.50; P = 0.05) in subacute TBAD. Apart from these findings, there was little difference in other incidents between the 2 groups. Regarding late outcomes, we observed significantly higher rates of retrograde dissection (OR, 2.12; 95% CI, 1.04-4.34; P = 0.04), distal stent-induced new entry (OR, 2.39; 95% CI, 1.24-4.61; P = 0.009), and reintervention (OR, 1.45; 95% CI, 0.05-1.99; P = 0.02) in acute TBAD than in subacute TBAD, whereas no significant differences were found for other outcomes between the 2 groups. Also, TEVAR appeared to yield comparable results for false lumen thrombosis and true lumen regression in both groups.

CONCLUSIONS

Subacute TBAD repair with TEVAR demonstrates a more effective reduction in adverse event rates compared to immediate treatment in the acute phase.

Risk factors for incomplete thrombosis in false lumen in sub-acute type B aortic dissection post-TEVAR

There is scarce information about the risk factors for incomplete false lumen thrombosis (FLT) among type B aortic dissection (AD) patients, particularly in the sub-acute phase following thoracic endovascular aortic repair (TEVAR). We enrolled consecutive sub-acute type B AD patients at Xinqiao Hospital (Chongqing, China) from May 2010 to December 2019. Patients with severe heart failure, cancer, and myocardial infarction were excluded. The postoperative computed tomography angiography (CTA) data were extracted from the most recent follow-up aortic CTA. Multivariate logistic regressions were applied to identify the association between FLT and clinical or imaging factors. Fifty-five subjects were enrolled in our study. Twelve participants showed complete FLT, and 2 of these died during the follow-up, while 8 patients died in incomplete FLT group. In the multivariate analysis, maximum abdominal aorta diameter (OR 1.20, 95% CI 1.016-1.417 p = 0.032) and the number of branches arising from the false lumen (FL) (OR 15.062, 95% 1.681-134.982 p = 0.015) were significantly associated with incomplete FLT. The C-statistics was 0.873 (95% CI 0.773-0.972) for the model. The FL diameter (p < 0.001) was significantly shorter following TEVAR, while the true lumen diameter (p < 0.001) and maximum abdominal aorta diameter (p = 0.011) were larger after the aortic repair. There were 21.8% of sub-acute type B AD patients presented complete FLT post-TEVAR. Maximum abdominal aorta diameter and the number of branches arising from the FL were independent risk factors for incomplete FLT. The true lumen diameter, maximum abdominal aorta diameter, and FL diameter changed notably following TEVAR.

Long-term Results of Thoracic Endovascular Aortic Repair for Type B Aortic Dissection and Risk Factors for Survival

Purpose: To compare characteristics of acute, subacute, and chronic type B aortic dissection and their influence on long-term results of thoracic endovascular aortic repair (TEVAR). Materials and Methods: In a single-center, retrospective cohort study, 314 patients (median age 52 years; 244 men) with acute (n=165), subacute (n=115), or chronic (n=34) type B aortic dissection underwent TEVAR between January 2009 and December 2013. Patient demographics, risk factors, and imaging characteristics were compared among the groups. Univariable and multivariable Cox regression analyses were performed to identify any factors influencing survival. Results: The acute and subacute patients exhibited more complications at presentation than chronic patients. However, the chronic patients exhibited more aneurysmal dilatation (p<0.001) and true lumen collapse (p<0.001). Over a mean follow-up of 68.1±22.9 months (range 2–108), subacute patients showed a lower reintervention rate (3.6% vs 12.1% vs 12.1%, p=0.045), a lower major complication rate (14.4% vs 33.1% vs 27.3%, p=0.002), and better cumulative overall survival (p=0.03) than the acute and chronic groups, respectively. Furthermore, acute patients developed more stent-graft–induced distal erosion (p=0.017) and retrograde type A dissection (RTAD) (p=0.036), whereas chronic patients had less aortic remodeling in the stented segment (p<0.001), distal thoracic aorta (p<0.001), and abdominal aorta (p=0.047). Finally, multivariable analysis demonstrated age >52 years, visceral malperfusion, and RTAD as independent factors influencing overall survival; aneurysmal dilatation, rupture/impending rupture, and RTAD were independent factors influencing aorta-specific survival. Conclusion: Acute and subacute patients had increased risks of rupture and complications at presentation, whereas chronic patients had increased risks for aneurysmal dilatation. From a long-term perspective, the subacute phase might be an optimal time for TEVAR in cases of type B aortic dissection that do not need emergent interventions. The risk factors influencing survival should be identified, carefully managed, and possibly prevented.