Secondary Interventions after Endovascular Repair of Aortic Dissections

Endovascular therapies for Type B Aortic Dissection

Aortic dissection is a life-threatening condition resulting from a tear in the intimal layer of the aorta, requiring emergent diagnosis and prompt multi-disciplinary management strategy for best patient outcomes. While type A dissection involving ascending aorta is best managed surgically due to high early mortality, type B aortic dissection (TBAD) involving descending aorta generally has better outcomes with conservative management and medical therapy as primary strategy is favored. However, there has been a recent paradigm shift in management of TBAD due to late aneurysmal degeneration of TBAD increasing morbidity and mortality at longer-term. Late surgical intervention can be prevented by early endovascular intervention when combined with optimal medical therapy. In this narrative review, we explore available literature on different endovascular therapies for TBAD in different populations of patients.

Predicting reintervention after thoracic endovascular aortic repair of Stanford type B aortic dissection using machine learning

OBJECTIVES

To construct models for predicting reintervention after thoracic endovascular aortic repair (TEVAR) of Stanford type B aortic dissection (TBAD).

METHODS

A total of 192 TBAD patients who underwent TEVAR were included; 68 (35.4%) had indications for reintervention. Clinical characteristics, aorta characteristics on pre- and postoperative computed tomography angiography, and aorta characteristics on immediate postoperative aortic digital subtraction angiography were collected. The least absolute shrinkage and selection operator (LASSO) regression was applied to identify the risk factors for reintervention. Eight classifiers were used for modeling. The models were trained on 100 train-validation random splits with a ratio of 2:1. The performance was evaluated by the receiver operating characteristic curve.

RESULTS

Seven predictors of reintervention were identified, including maximum false lumen diameter, aortic diameter measured at the level of approximately 15 mm distal to the left subclavian artery, aortic diameter measured at the level of the diaphragm, false lumen diameter measured at the level of the celiac artery, number of bare-metal and covered stents, number of bare-metal stents, and residual perfusion of the false lumen. Logistic regression (LR) yielded the highest performance, with an area under the curve of 0.802. A nomogram built for clinical use showed good calibration. The cutoff value for dividing patients into low- and high-risk subgroups was 0.413. Kaplan-Meier curves showed that the overall survival of high-risk patients was significantly shorter than that of low-risk patients (both p < 0.05).

CONCLUSION

Our nomogram could predict the reintervention after TEVAR in patients with TBAD, which may facilitate patient selection and surveillance strategies.

KEY POINTS

• Seven risk factors of reintervention after TEVAR of TBAD were identified for modeling. • Logistic regression performed best in predicting reintervention with an AUC of 0.802. • Patients with a high risk of reintervention had shorter OS than those with a low risk.

Adjunctive false lumen intervention for chronic aortic dissections is safe but offers unclear benefit

OBJECTIVE

Adjunctive false lumen embolization (FLE) with thoracic endovascular aortic repair (TEVAR) in patients with chronic aortic dissection is thought to induce FL thrombosis and favorable aortic remodeling. However, these data are derived from small single-institution experiences and the potential benefit of FLE remains unproven. In this study, we examined perioperative and midterm outcomes of patients with aortic dissection undergoing concomitant TEVAR and FLE.* METHODS: Patients 18 or older who underwent TEVAR for chronic aortic dissection with known FLE status in the Society for Vascular Surgery Vascular Quality Initiative database between January 2010 and February 2020 were included. Ruptured patients and emergent procedures were excluded. Patient characteristics, operative details and outcomes were analyzed by group: TEVAR with or without FLE. Primary outcomes were in-hospital post-operative complications and all-cause mortality. Secondary outcomes included follow-up mean maximum aortic diameter change, rates of false lumen thrombosis, re-intervention rates, and mortality.

RESULTS

884 patients were included: 46 had TEVAR/FLE and 838 had TEVAR alone. There was no significant difference between groups in terms of age, gender, comorbidities, prior aortic interventions, mean maximum pre-operative aortic diameter (5.1cm vs. 5.0cm, P=0.43), presentation symptomatology, or intervention indication. FLE was associated with significantly longer procedural times (178min vs. 146min, P=0.0002), increased contrast use (134mL vs. 113mL, P=0.02), and prolonged fluoroscopy time (34min vs. 21min, P<0.0001). However, FLE was not associated with a significant difference in post-operative complications (17.4% vs. 13.8%, P=0.51), length of stay (6.5 vs. 5.7 days, P=0.18), or in-hospital all-cause mortality (0% vs. 1.3%, P=1). In mid-term follow-up (median 15.5months, IQR 2.2-36.2 months), all-cause mortality trended lower, but was not significant (2.2% vs. 7.8%); and Kaplan-Meier analysis demonstrated no difference in overall survival between groups (P=0.23). By Cox regression analysis, post-operative complications had the strongest independent association with all-cause mortality (HR 2.65, 95% CI 1.56-4.5, P<0.001). In patients with available follow-up imaging and re-intervention status, mean aortic diameter change (n=337, -0.71cm vs. -0.69cm, P=0.64) and re-intervention rates (n=487, 10% vs. 11.4%, P=1) were similar.

CONCLUSIONS

Adjunctive FLE, despite increased procedural times, can be performed safely for patients with chronic dissection without significantly higher overall perioperative morbidity or mortality. TEVAR/FLE demonstrates trends for improved survival and increased rates of FL thrombosis in the treated thoracic segment; however, given the lack of evidence to suggest a significant reduction in re-intervention rates or induction of more favorable aortic remodeling compared to TEVAR alone, the overall utility of this technique in practice remains unclear. Further investigation is needed to determine the most appropriate role for FLE in managing chronic aortic dissections.

Endovascular management of chronic symptomatic aortic dissection with the Streamliner Multilayer Flow Modulator: Twelve-month outcomes from the global registry

OBJECTIVE

Reported are initial 12-month outcomes of patients with chronic symptomatic aortic dissection managed by the Streamliner Multilayer Flow Modulator (SMFM; Cardiatis, Isnes, Belgium). Primary end points were freedom from rupture- and aortic-related death, and reduction in false lumen index. Secondary end points were patency of great vessels and visceral branches, and freedom of stroke, paraplegia, and renal failure.

METHODS

Out of 876 SMFM implanted globally, we have knowledge of 542. To date, 312 patients are maintained in the global registry, of which 38 patients were identified as having an aortic dissection (12.2%). Indications included 35 Stanford type B dissections, two Stanford type A and B dissections, and one mycotic Stanford type B dissection.

RESULTS

There were no reported ruptures or aortic-related deaths. All cause survival was 85.3% Twelve-month freedom from neurologic events was 100%, and there were no incidences of end-organ ischemia, paraplegia or renal insult. Morphologic analysis exhibited dissection remodeling by a reduction in longitudinal length of the dissected aorta, and false lumen volume. A statistically significant reduction in false lumen index (P = .016) at 12 months, and a borderline significant increase in true lumen volume (P = .053) confirmed dissection remodeling.

CONCLUSIONS

The SMFM is an option in management of complex pan-aortic dissection. Results highlight SMFM implantation leads to dissection stabilization with no further aneurysm progression, and no retrograde type A dissection. Thoracic endovascular aneurysm repair by SMFM ensued in freedom from aortic rupture, neurologic stroke, paraplegia and renal failure. Further analysis of the global registry data will inform long-term outcomes.