Thoracic Endovascular Aortic Repair for Type B Aortic Dissection

Early Results of the Newly-Designed Flowdynamics Dense Mesh Stent for Residual Dissection After Proximal Repair of Stanford Type A or Type B Aortic Dissection: A Preliminary Single-Center Report From a Multicenter, Prospective, and Randomized Study

BACKGROUND

Negative remodeling of the distal aorta due to residual dissection significantly impacts the long-term outcomes of dissection patients after proximal repair of acute aortic dissection. Branched/fenestrated aortic stents are technically demanding, and studies of the first generation of multilayer flow modulators for tackling this clinical scenario are few and limited. The single-center results from a multicenter, prospective, and randomized controlled study aimed to verify the safety and effectiveness of a newly-designed flowdynamics dense mesh stent for treating residual dissection after proximal repair.

METHODS

Patients with nonchronic residual dissection involving visceral branches were prospectively enrolled in 3 centers (ChiCTR1900023638). Eligible patients were randomly assigned to the flowdynamics dense mesh stent (FDMS) group and control group. Follow-up visits were arranged at 1, 3, 6, and 12 months after recruitment. The primary endpoints were all-cause and aortic-related mortality. The secondary endpoints included visceral branch occlusion, reintervention, and severe adverse events. Morphological changes were analyzed to exhibit the therapeutic effect. Our center participated in the multicenter prospective randomized controlled trial, and the preliminary single-center experience was reported.

RESULTS

Thirty-six patients were enrolled in our center, and the baseline characteristics of the 2 groups were comparable. Thirty-four patients completed the 12 month follow-up. Freedom from all-cause and aortic-related death were 94.4% and 100%. All visceral branches remained patent in the FDMS group. Increased area of the true lumen (1.03±0.38 vs 0.48±0.63 cm2 at the plane below renal arteries, p=0.006; 1.27±0.80 vs 0.32±0.50 cm2 at the plane 5 cm below renal arteries, p<0.001) and decreased area of the false lumen at the plane below renal arteries (-1.03±0.84 vs -0.15±1.21 cm2, p=0.023) were observed in the FDMS group compared with those parameters in the control group. The FDMS group showed a significant increase in true lumen volume (p<0.001) and a significant decrease in false lumen volume (p=0.018).

CONCLUSIONS

This newly-designed FDMS for endovascular repair of residual dissection after the proximal repair is safe and effective at 12 months.

CLINICAL IMPACT

One-year results of the randomized controlled clinical trial indicated the short-term safety and promising effect of FDMS on treating non-chronic residual dissection after proximal repair. At the 12th-month follow-up, the true lumen expanded, the false lumen shrunk and all visceral arteries kept patent. As far as I'm concerned, this is the first randomized controlled study concerning utilizing multilayer flow mesh stent treating aortic dissection. Despite a preliminary single-center report, our results are supposed to provide high-quality evidence to guide clinical practice and fill the gap in the application of FDMS.

One-year results of the Flowdynamics Dense Mesh Stent for residual dissection after proximal repair of stanford type A or type B aortic dissection: a multicenter, prospective, and randomized study

OBJECTIVE

Negative remodeling of the distal aorta following proximal repair for acute aortic dissection has garnered growing attention. This clinical scenario has spurred the development of techniques and devices. A multicenter, prospective, and randomized controlled study was conducted with the aim of confirming the safety and effectiveness of a newly-designed flowdynamics dense mesh stent for the treatment of residual dissection after proximal repair.

METHODS

Patients with nonchronic residual dissection affecting visceral branches were prospectively enrolled at three centers and randomly allocated to either the FDMS group or the control group. Primary endpoints encompassed all-cause and aortic-related mortality, while the patency of branch arteries is indeed a key focal metric. Morphological changes (diameter, area, and volume) were analyzed to demonstrate the therapeutic effect.

RESULTS

One hundred twelve patients were recruited in the clinical trial, and 103 patients completed the 12-month follow-up. The rate of freedom from all-cause and aortic-related death in the FDMS group was 94.64 and 100%, respectively. All visceral branches remained patent. The FDMS group exhibited a substantial expansion in TL and a notable shrinkage in FL at the planes below renal arteries (ΔArea TL : FDMS vs. Control, 0.74±0.46 vs. 0.34±0.66 cm 2 , P <0.001; ΔArea FL : FDMS vs. Control, -0.72±1.26 vs. -0.12±0.86 cm, P =0.01) and 5 cm below renal arteries (ΔArea TL : FDMS vs. Control, 1.06±0.75 vs. 0.16±0.63 cm 2 , P <0.001; ΔArea FL : FDMS vs. Control, -0.53±1.43 vs. -0.25±1.00 cm, P =0.27). Meanwhile, the FDMS group demonstrated an increase of 22.55±11.14 cm 3 in TL ( P <0.001) and a corresponding reduction of 21.94±11.77 cm 3 in FL ( P =0.08).

CONCLUSIONS

This newly-designed FDMS for endovascular repair of residual dissection following the proximal repair is demonstrated to be safe and effective at 12 months.

Timing of Intervention and Long-Term Outcomes of Type B Aortic Intramural Hematoma with Intimal Disruption at Admission

BACKGROUND

To compare the 30-day and long-term outcomes between patients with concomitant type B intramural hematoma and intimal disruption upon admission who underwent endovascular repair in the acute or subacute phases.

METHODS

Data were extracted from January 1, 2010, to December 31, 2019. Logistic regression and Cox regression were performed to evaluate the impact of timing of intervention on 30-day and long-term outcomes, respectively.

RESULTS

The study included 241 patients, among which 159 were in the acute group. No significant difference was observed in 30-day mortality (0.6% vs. 0%, P = 1), 30-day complication rate (2.5% vs. 1.2%, P = 0.664), long-term all-cause mortality (10.7% vs. 7.3%, P = 0.540), and aortic reintervention rate (2.5% vs. 2.4%, P = 1) between the acute and subacute group. In multivariable analysis, the timing of intervention was not associated with 30-day mortality (odds ratio (OR) = 0, 95% confidence interval CI: 0-Inf, P = 0.999), 30-day complication (OR = 0.30, 95% CI: 0.02-3.77, P = 0.348), long-term mortality (hazard ratio = 0.56, 95% CI: 0.20-1.61, P = 0.283), and aortic reintervention (OR = 0.97, 95% CI: 0.15-6.08, P = 0.970).

CONCLUSIONS

For patients with concomitant type B intramural hematoma and intimal disruption upon admission, there is no significant difference in 30-day and long-term outcomes between those who undergo endovascular treatment in the acute or subacute phase.

Management of Isolated Abdominal Aortic Dissection: Indications and Strategies for Treatment

BACKGROUND

The aim of this paper was to report our experience in the management of isolated abdominal aortic dissection with endovascular aortic repair and conservative treatment.

METHODS

A cohort of 22 consecutive patients with isolated abdominal aortic dissection was treated between January 2016 and December 2021. We reviewed the demographics, clinical features, therapeutic modalities and follow-up results. Retrospective data analysis from patient charts was performed.

RESULTS

Twenty-two patients were enrolled in this study from 2 centers. The mean age was 66.2 ± 13.3 years. Hypertension was the primary risk factor. Seventeen (72.7%) patients were asymptomatic, and 18 patients were subrenal artery type (type II). A total of 12 patients had successful endovascular repair (EVAR), and 10 patients underwent conservative treatment. In the group receiving conservative treatment, no patients required EVAR during follow-up, and 4 patients died. However, none of them had aortic causes: 2 patients had cardiac causes, the other 2 had cancer, and the others remained symptom-free. The latest computed tomographic angiography images showed that abdominal aortic dissection still existed, and the extent of the false lumen did not increase significantly.

CONCLUSIONS

Both conservative treatment and EVAR are effective treatment options. Appropriate treatment needs to be performed according to different patients' clinical manifestations and doctors' experience.

Endovascular repair of acute vs. subacute uncomplicated type B aortic dissection: a systematic review and meta-analysis

Objective

This study aimed to conduct a meta-analysis evaluating the optimal timing for endovascular repair of acute versus subacute uncomplicated Type B Aortic Dissection.

Method

PubMed, EMBASE, web of science and Cochrane Library was interrogated to identify Electronic bibliographic studies updated to January 2023 to collect studies compared the clinical outcomes of endovascular repair for Acute Versus Subacute Uncomplicated Type B Aortic Dissection. Data were aggregated as pooled odds ratios (OR) using the fixed or random effects models according to the significance of heterogeneity, Pooled odds ratios (OR) were calculated by RevMan 5.3 and applied with fixed or random-effect models.

Result

A comprehensive literature search found 322 citations published and finally among them 6 studies containing 3,769 patients (acute group 2,642, subacute group 1,127) were included in review. There is an increased risk of 30-day complications (OR = 1.51,95%CI,1.26-1.81) 30-day mortality (OR = 2.39,95%CI, 1.55-3.67) and 1-year mortality (OR = 1.71,95%CI,1.27-2.30) for an acute uTBAD group compared to subacute ones. Similarly, reintervention was more likely in the acute group than in the subacute group (OR = 1.42,95%CI,1.05-1.91). However, no significant differences were found in long-term mortality.

Conclusion

This meta-analysis confirmed that there was no significant difference in the long-term prognosis between the acute and subacute phases in the timing of surgery. However, considering the high incidence of complications, high re-intervention rate and one-year mortality probably caused by high intima fragility in the acute phase, endovascular repair at subacute phase appears to favorably compare with acute strategy. But future studies with adequate patient numbers and longer-term follow-up are necessary to further verify the study conclusion.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021247609, identifier PROSPERO CRD42021247609.

Five-Year Results of Aortic Remodeling for Acute, Subacute, and Chronic Type B Aortic Dissection Following Endovascular Repair

Background

This study was performed to compare aortic remodeling and clinical outcomes in patients with acute, subacute, and chronic type B aortic dissection (TBAD) after thoracic endovascular aortic repair (TEVAR).

Methods

We retrospectively examined 323 consecutive patients with acute (n = 129), subacute (n = 161), and chronic (n = 33) TBAD who underwent TEVAR from June 2013 to December 2016 in in multicenter institution. Patient demographics, clinical data, and imaging characteristics were recorded and compared among the three groups.

Results

The three groups had comparable baseline characteristics. Perioperative mortality rates were similar among the acute (2.3%), subacute (0.0%), and chronic (0.0%) groups (P = 0.34). Perioperative morbidity rates, including the rates of visceral and lower limb malperfusion and cerebral infraction, were also similar. The rate of perioperative endoleak was significantly higher in the chronic group (18.1%) than in the acute (3.9%) and subacute (3.7%) groups (P = 0.02). The mean follow-up duration was 78 ± 22 months (range, 36–101 months). The mortality rates were comparable among the three groups. The rates of reintervention and lower limb malperfusion were higher in the chronic group than in the acute and subacute groups. FL diameter reduction were more robust in the acute and subacute groups than in the chronic group.

Conclusion

Patients with acute, subacute, and chronic TBAD had different outcomes in this study. Patients with acute and subacute TBAD had fewer complications than those with chronic TBAD. Aortic remodeling after TEVAR was more favorable in patients with acute and subacute TBAD than in patients with chronic TBAD. TEVAR promotes more positive remodeling at the stent graft level than at the distal level of the aorta.

Impact of high-risk features and timing of repair for acute type B aortic dissections

OBJECTIVE

The new Society for Vascular Surgery/Society for Thoracic Surgery reporting standards for type B aortic dissection (TBAD) categorize clinical presentations of aortic dissection into uncomplicated, high-risk features (HRF), and complicated groups. Although it is accepted that complicated dissections require immediate repair, the optimal timing of repair for HRF has yet to be established. This study aims to identify the ideal timing of thoracic endovascular aortic repair (TEVAR) for HRF, as well as outcomes associated with specific HRF.

METHODS

The Vascular Quality Initiative was queried for TEVARs performed for acute and subacute TBAD with HRF from 2014 to 2020. Rupture, malperfusion, and uncomplicated patients were excluded. HRF were defined per the guidelines as refractory hypertension, pain, or rapid expansion/aneurysm of more than 40 mm. The primary outcomes were in-hospital/30-day mortality and 1-year survival with primary exposure variables being days from symptoms to repair and number of HRFs. Secondary outcomes were spinal cord ischemia, stroke, and retrograde type A dissection (RTAD).

RESULTS

Of the 1100 patients who met inclusion criteria, 811 had one HRF, 249 had two, and 40 had three. There were no significant differences in primary or secondary outcomes based on number of HRFs. There were 309 patients who underwent repair at 0 to 2 days, 262 at 3 to 6 days, 270 at 7 to 14 days, and 259 at 15 days or more. TEVAR performed at 15 days or more was independently associated with lower in-hospital/30-day mortality (odds ratio, 0.38; P = .0388) and improved 1-year survival. Postoperative stroke was associated with earlier repair (0-2 days). There was no association of timing of repair with spinal cord ischemia, retrograde type A dissection or reintervention.

CONCLUSIONS

TEVAR for TBAD with HRF delayed at least 15 days from symptom onset is associated with improved survival, supporting the theory that it is best to delay TEVAR until the subacute phase. Additionally, TEVAR delayed at least 3 days is associated with a decrease in stroke. Having more than one HRF was not associated statistically with worse outcomes. Because the classification of HRF is relatively new and without guidelines for repair, this study highlights the risks of early intervention for HRF and suggests that these patients seem to benefit from at least a short stabilization period before TEVAR.

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.

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.

Multilayer flow modulator enhances vital organ perfusion in patients with type B aortic dissection

Management of aortic dissections (AD) is still challenging, with no universally approved guideline among possible surgical, endovascular, or medical therapies. Approximately 25% of patients with AD suffer postintervention malperfusion syndrome or hemodynamic instability, with the risk of sudden death if left untreated. Part of the issue is that vascular implants may themselves induce flow disturbances that critically impact vital organs. A multilayer mesh construct might obviate the induced flow disturbances, and it is this concept we investigated. We used preintervention and post-multilayer flow modulator implantation (PM) geometries from clinical cases of type B AD. In-house semiautomatic segmentation routines were applied to computed tomography images to reconstruct the lumen. The device was numerically reconstructed and adapted to the PM geometry concentrically fit to the true lumen centerline. We also numerically designed a pseudohealthy case, where the geometry of the aorta was extracted interpolating geometric features of preintervention, postimplantation, and published representative healthy volunteers. Computational fluid dynamics methods were used to study the time-dependent flow patterns, shear stress metrics, and perfusion to vital organs. A three-element Windkessel lumped parameter module was coupled to a finite-volume solver to assign dynamic outlet boundary conditions. Multilayer flow modulator not only significantly reduced false lumen blood flow, eliminated local flow disturbances, and globally regulated wall shear stress distribution but also maintained physiological perfusion to peripheral vital organs. We propose further investigation to focus the management of AD on both modulation of blood flow and restoration of physiologic end-organ perfusion rather than mere restoration of vascular lamina morphology. NEW & NOTEWORTHY The majority of aortic dissection modeling efforts have focused on the maintenance of physiological flow using minimally invasive placed grafts. The multilayer flow modulator is a complex mesh construct of wires, designed to eliminate flow disruptions in the lumen, regulate the physiological wall stresses, and enhance endothelial function and offering the promise of improved perfusion of vital organs. This has never been fully proved or modeled, and these issues we confirmed using a dynamic framework of time-varying arterial waveforms.

Endovascular treatment of acute and chronic isolated abdominal aortic dissection

Objective

To discuss the strategies and clinical outcomes of endovascular aortic repair (EVAR) for acute and chronic isolated abdominal aortic dissection (IAAD).

Methods

From January 2012 to June 2017, 33 patients with IAAD were retrospectively reviewed. Patients were classified into acute and chronic groups based on the time to EVAR from IAAD onset (acute: ≤90 days; chronic: >90 days). Patient demographics, clinical parameters, procedural factors, and clinical outcomes were evaluated and compared between the two groups.

Results

Among 33 patients, 21 were diagnosed with acute IAAD and 12 were diagnosed with chronic IAAD. All patients underwent EVAR, and no significant difference in EVAR-related procedural factors was observed between the two groups. The primary technical success rate in all patients was 100%. The overall survival rate in the chronic group was lower than that in the acute group, but the difference was not statistically significant ( P = 0.186). However, the reintervention-free survival rate in the chronic group was significantly lower than that in the acute group ( P = 0.039). Significant enlargement of the true lumen (TL) and regression of the false lumen (FL) and maximal aortic diameter were observed in all patients after EVAR ( P < 0.05). The mean diameter of the TL in the acute group increased significantly more than that in the chronic group (14 ± 3 mm vs. 11 ± 3 mm, P = 0.040). A significant difference was not observed in the regression of the FL ( P = 0.628) or maximal aortic diameter ( P = 0.319) between the two groups.

Conclusion

EVAR continues to be a safe therapeutic approach with a high technical success rate and favorable clinical outcomes. The clinical outcomes and aortic remodeling in the chronic group seem to be poorer than those in the acute group.

Early and midterm outcomes of thoracic endovascular aortic repair (TEVAR) for acute and chronic complicated type B aortic dissection

Thoracic endovascular aortic repair (TEVAR) in the current era has been chosen as a dominant and minimally invasive treatment for complicated aorta dissection. This study aimed to assess safety and feasibility of TEVAR in acute and chronic type B aortic dissection.Between January 2011 and December 2013, 85 patients with complicated type B aortic dissection undergoing TEVAR were divided into acute aortic dissection (AAD) (n = 60) group and chronic aortic dissection (CAD) group (n = 25). Computed tomography was used to evaluate postoperative changes in maximal aortic diameter and true and false lumen diameters at 3 levels during a mean follow-up period of 26.4 ± 15.6 months.The technical success rate was 100%. In-hospital and 30-day rates of death were 3.3% in acute group and 0 in chronic group. Postdischarge rates of type I leak, type II leak, and retrograde type A dissection were 6.7%, 5.2%, and 3.4% (acute) and 0%, 4.0%, and 4.0% (chronic), respectively. The maximal aorta diameter remained stable in all the 3 levels in both acute and chronic group. The cumulative freedom from all-cause mortality at 3 years was similar in acute and chronic groups (89.5% vs 95.5%, P = .308). The cumulative freedom from aortic-related mortality was also not significantly different in the acute and chronic groups (92.8% vs 95.2%, P = .531). In the thoracic aorta, TEVAR treatment resulted in a significant increase in true lumen (TL) diameter and decrease in false lumen (FL). However, in the abdominal aorta, TEVAR did not lead to significant change in TL and FL diameters. The rates of complete thrombosis thoracic false lumens were better than that in the abdominal false lumen.TEVAR was a safe and effect therapy for complicated acute and chronic type B dissection with low early and mid-term mortality and morbidity.