Uncomplicated Type B Aortic Dissection: Complicated Choices

The Impact of Oversizing in Thoracic Endovascular Aortic Repair on Long-Term Outcomes in Uncomplicated Type B Aortic Dissection: A Single-Center Retrospective Study

PURPOSE

The purpose of this study was to assess the impact of oversizing in thoracic endovascular aortic repair (TEVAR) on early and long-term survival and major adverse events in patients with uncomplicated type B aortic dissection (TBAD).

METHODS

Between January 2010 and December 2018, 226 patients who were diagnosed with uncomplicated TBAD and received TEVAR were analyzed retrospectively. The patients were divided into ≤5% oversizing (n=153) and >5% oversizing (n=73) groups. Primary end points were all-cause and aortic-related mortalities. Secondary end points were procedure-related complications, including retrograde type A aortic dissection (RTAD), endoleak, distal stent-induced new entry (SINE), and late reintervention. All-cause and aortic-related mortalities were assessed using the Kaplan-Meier survival method, while procedure-related complications were evaluated using a competing risk model with all-cause death as a competing risk.

RESULTS

Mean oversizing was 2.1%±1.5% in the ≤5% oversizing group and 9.6%±4.1% in the >5% oversizing group. Differences in the 30-day mortality and adverse events between the 2 groups were statistically insignificant. The freedom from all-cause mortality was comparable between the ≤5% oversizing group and the >5% oversizing group (≤5%: 93.3% at 5 years, >5%: 92.3% at 5 years, p=0.957). No significant difference was observed between both groups in the freedom from aortic-related mortality (≤5%: 95.0% at 5 years, >5%: 96.7% at 5 years, p=0.928). However, the competing risk analyses revealed that the cumulative incidence of RTAD was statistically significantly greater in the >5% oversizing group than in the ≤5% oversizing group (≤5%: 1(0.7%) at 5 years, >5%: 6(6.9%) at 5 years, p=0.007). All RTADs occurred within a year of TEVAR. The differences in the cumulative incidences of type I endoleak, distal SINE, and late reintervention were not significant between the 2 groups.

CONCLUSION

The differences in the 5-year all-cause mortality and aortic-related mortality between patients with uncomplicated TBAD who received TEVAR with ≤5% oversizing and those who got TEVAR with >5% oversizing were insignificant. However, oversizing >5% was considerably associated with an increased risk of RTAD within a year of TEVAR, suggesting that oversizing ≤5% may be the appropriate size for TEVAR in patients with uncomplicated TBAD.

CLINICAL IMPACT

For patients with uncomplicated TBAD, choosing oversizing ≤5% in endovascular treatment is beneficial to reduce the risk of postoperative retrograde type A aortic dissection. This finding provides a basis for stent size selection in endovascular repair. In addition, one year after TEVAR is the main time period for postoperative retrograde type A aortic dissection, and attention should be paid to the management and follow-up of this period.

Impact of post-implantation syndrome on outcomes in acute type B aortic syndrome patients undergoing endovascular repair

Background: The aim of this study was to explore the impact of post-implantation syndrome (PIS) on prognosis outcomes in individuals with type B acute aortic syndrome (AAS) undergoing thoracic endovascular aortic repair (TEVAR). Patients and methods: Data from type B AAS individuals who underwent TEVAR from January 2014 to April 2021 were retrospectively reviewed. Study subjects were divided into PIS and non-PIS (nPIS) groups and postoperative clinical outcomes were analyzed. Results: Our study cohort of 74 individuals with type B AAS included 40 aortic dissection (AD), 30 intramural hematoma (IMH), 4 penetrating aortic ulcer (PAU). The incidence of PIS was 14.9%. No statistically significant differences were found in baseline characteristics. The left subclavian artery (LSCA) reconstruction was performed more frequently among the PIS group (45.5% vs 9.5%, p=.008). Major adverse events (MAE) tended to be more frequent in the PIS group, but the difference was not significant (27.3% vs 22.2%, p=.707). At 2-year follow-up, results were comparable between the two groups. Kaplan-Meier analysis showed that PIS was not associated with a higher incidence of mortality, endoleak, new-onset AD, or stroke. A baseline neutrophil-to-lymphocyte ratio (NLR) >10.3 was associated with greater incidence of MAE. In individuals with IMH, better aortic remodeling evaluated by lower total aortic diameter/true lumen diameter (TAD/TLD) was achieved in the nPIS group (1.23±0.10 vs 1.43±0.07, p<.001), and a TAD/TLD ratio >1.32 was associated with significantly more MAE. Cox multivariate regression analysis also showed that a postoperative TAD/TLD ratio >1.32 was an independent risk factor for MAE (OR, 11.36; 95% CI, 1.53-84.26; p=.017). Conclusions: PIS was associated with a trend toward a higher incidence of MAE after TEVAR. In individuals with IMH, a TAD/TLD ratio >1.32 was an independent predictor of postoperative MAE.

Hemodynamic Implications of STABILISE Technique for Aortic Dissection Repair

BACKGROUND

The stent-assisted balloon-induced intimal disruption and relamination (STABILISE) technique for treatment of type B dissection has shown promising clinical results at mid-term. Computational modeling is a way of noninvasively obtaining hemodynamic effects, such as pressure and wall shear stress, leading to a better understanding of potential benefits. Particular areas of interest are (1) the effect of intimal disruption and re-lamination and (2) the effect of the bare metal stent in the visceral aortic segment.

METHODS

Single-center prospective case series. Data from 5 consecutive locally performed cases of STABILISE technique were analyzed. Included cases were type B aortic dissection with or without prior de-branching. The STABILISE procedure had to be performed without 30-day major complications. Preoperative and postoperative imaging data for each patient were transferred to the biomedical engineering team. Each case was reconstructed, meshed, and simulated with computational fluid dynamics using patient-specific data (heart rate, blood pressure, height, and weight). Hemodynamic parameters were then extracted from the simulations.

RESULTS

In all cases, computational analysis showed for postoperative patients: (1) a drop in pressure difference between lumina and (2) lower wall shear stress effects, compared to their preoperative status. These observations were most pronounced in the visceral aortic segment.

CONCLUSIONS

Computational modeling shows favourable changes in the flow dynamics of type B dissection treated using the STABILISE technique. This may suggest protective effects of this technique for long-term aortic healing and cicatrization.

Risk factors for distal stent graft-induced new entry after endovascular repair in uncomplicated type B aortic dissection

OBJECTIVE

We investigated the risk factors for distal stent graft-induced new entry (dSINE) after thoracic endovascular aortic repair for patients with uncomplicated type B aortic dissection (TBAD) and reported the outcomes of using a tapered stent graft and dSINE reintervention.

METHODS

A total of 226 patients with uncomplicated TBAD who had undergone thoracic endovascular aortic repair between January 2010 and December 2018 were analyzed retrospectively. The global features of the thoracic aorta and the local features of the proximal and distal landing zones were evaluated and compared between the dSINE and non-dSINE groups. A multivariate Cox model was used to identify the independent risk factors for dSINE. The cumulative incidence of reintervention was estimated using competing risk models.

RESULTS

After a median follow-up of 4.6 years, 16 patients (7.1%) had developed dSINE. Multivariable Cox regression analysis demonstrated that a type III aortic arch, decreased angle, increased distal oversizing, and increased distal mismatch ratio were significant risk factors for dSINE. Of the patients with tapered stent grafts, five with a ≤4-mm taper had developed dSINE. However, no dSINE was seen in the >4-mm taper group (P = .024). Reintervention was performed for 7 of the 16 patients with dSINE (43.8%). The mean time from the initial detection of dSINE to reintervention was 6.43 ± 4.62 months. The competing risk analyses showed that the cumulative incidence of reintervention in the dSINE group at 1, 3, and 5 years was 25.0%, 37.5%, and 43.5%, respectively.

CONCLUSIONS

A type III aortic arch, excessive distal oversizing and mismatch ratio, and severe angulation were associated with dSINE in patients with uncomplicated TBAD. The use of a tapered stent graft with a >4-mm taper could help prevent dSINE in patients with a high taper ratio. Aggressive reintervention was associated with favorable long-term outcomes for patients with progressive dSINE.

Timing of endovascular repair impacts long-term outcomes of uncomplicated acute type B aortic dissection

OBJECTIVE

To compare the 5-year outcomes of acute versus subacute thoracic endovascular aortic repair (TEVAR) in patients with uncomplicated acute type B aortic dissection (ATBAD).

METHODS

Between March 2008 and September 2018, 238 consecutive patients with uncomplicated ATBAD underwent TEVAR in the acute or subacute phase and were analyzed retrospectively. The primary end points were all-cause death and aortic-related death. The secondary end point was a composite of the outcomes of death from any cause, rupture, new dissection, retrograde type A aortic dissection, endoleak, and late reintervention. Inverse probability treatment weighting was used to balance baseline characteristics. Weight-adjusted Kaplan-Meier estimate with landmark analysis and weighted Cox model were performed to assess time-to-event outcomes.

RESULTS

In the inverse probability treatment weighting-adjusted population, the 30-day mortality was 1.5% in the acute TEVAR group and 0% in the subacute TEVAR group (P = .24). The incidence of 30-day adverse events occurred in 16.8% and 6.9% patients in the acute TEVAR and subacute TEVAR groups, respectively (P = .13). At 5 years, there was no statistically significant difference in all-cause death (hazard ratio [HR], 1.50; 95% confidence interval [CI], 0.59-3.81; P = .39) and aortic-related death (HR, 1.11; 95% CI, 0.34-3.60; P = .86) between the two groups. The composite outcomes occurred in 30 patients (23.0%) in the acute TEVAR group and 18 patients (22.3%) in the subacute TEVAR group, respectively (HR, 0.67; 95% CI, 0.36-1.25; P = .20). However, a landmark analysis of the composite outcomes indicated that there was a significant interaction between treatment effect and time (P_interaction = .01), with a significantly higher incidence of the composite outcomes in the acute TEVAR group compared with the subacute TEVAR group within 1 year (HR, 0.25; 95% CI, 0.08-0.79; P = .02), and a comparable rate between 1 and 5 years (HR, 1.25; 95% CI, 0.56-2.76; P = .59).

CONCLUSIONS

At the 5-year follow-up, no significant differences exist in the all-cause death and aortic-related death between acute and subacute TEVAR. However, acute TEVAR is associated with an increased rate of severe complications within 1 year, which suggests that performing TEVAR in the subacute phase of ATBAD may be the preferable option.

Influence of Sex on Outcomes After Thoracic Endovascular Repair for Type B Aortic Dissection

We aimed to investigate whether sex differences influence the clinical outcomes of patients who undergo thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD). We retrospectively analyzed a prospectively maintained single-center cohort of patients with TBAD who underwent TEVAR between January 2010 and June 2017. We evaluated the in-hospital and long-term mortality and composite end point. Of the 913 patients, 793 (86.8%) were male and 120 (13.1%) were female. Compared to male patients, the female patients were older, more likely to have diabetes mellitus, but less likely to smoke or have hypertension. The proximal landing zone in 0 and 1 was higher in male patients (P = .023), who were more likely to require an aortic arch bypass. Endoleak, delirium, and ICU stay after stent-graft implantation were also more frequent in men. Sex factor was not associated with in-hospital or long-term mortality or the composite end point in the multivariable regression analyses and Cox regression model. The mean estimated survival time was similar between males and females (2462.9 ± 141.2 vs 2804.1 ± 117.4 days, P = .167) in the propensity score-matched cohort. Despite distinct characteristics between sex, there was no sex-related difference in long-term clinical outcomes after TEVAR for TBAD.