A meta-analysis of combined proximal stent grafting with or without adjunctive distal bare stent for the management of aortic dissection

Critical Review of Guidelines for Type B Aortic Dissection

The management of type B aortic dissection is one of the most challenging and debated topics in contemporary cardiovascular surgery practice. Patients with acute or chronic dissection-related complications face high morbidity and mortality if not treated promptly. For most patients requiring intervention, thoracic endovascular aortic repair (TEVAR) is considered the gold standard. However, both early and late TEVAR-related complications make decision-making complex, even for experienced clinicians. In many cases, optimal medical management with longitudinal imaging surveillance may be preferred. In response to these challenges, several societal guidelines have recently been published to provide evidence-based or expert consensus "best practice" recommendations. Although these guidelines share many commonalities, they also highlight key unresolved clinical questions. For example, debates persist over the appropriate use of TEVAR for "uncomplicated" TBAD, defining "high-risk" criteria for uncomplicated presentations, and management of the false lumen, among other topics. Despite recent updates, a critical evaluation of the nuanced differences between these guidelines is lacking. Therefore, the purpose of this review is to compare current clinical practice guidelines, highlight their similarities and differences, and offer a comprehensive evaluation of the evidence surrounding management of TBAD. Moreover, this analysis will provide recommendations to address important knowledge gaps.

Midterm Results of the STABILISE Technique in the Treatment of Aortic Dissection

Background: Contemporary treatments of acute aortic dissection, including medical, surgical, and endovascular options, are remarkably effective at the management of malperfusion and rupture. Unfortunately, long-term studies indicate that 30%-50% of patients need secondary procedures to treat progressive aneurysmal enlargement of the untreated aorta. The Stent-assisted balloon-induced intimal disruption and relamination in aortic dissection repair (STABILISE) technique was introduced to improve long-term outcomes. Purpose: This study aims to investigate the results of the STABILISE technique in patients with aortic dissection. Methods: This is a single-center, retrospective review of all patients treated with the STABILISE technique. There were 12 de novo type B aortic dissection (TBAD) and 7 residual TBAD following type A aortic dissection (TAAD) repair. Results: There was disruption of the dissection membrane and relamination in all or part of the bare metal stent segment in 100% of cases. The average percent attainment of a uni-luminal aorta in comparison to the length with persistent false lumen was 91 ± 12%. Conclusion: Midterm results suggest that the STABILISE technique may improve aortic remodeling after endovascular treatment of acute dissection.

Emerging Trends in the Care of Type B Aortic Dissections

Aortic dissection is the most common of the acute aortic syndromes. Acute aortic dissection remains a highly morbid and potentially lethal condition despite contemporary advances in medical and surgical care. Type B aortic dissection (TBAD) is classified as uncomplicated, uncomplicated with high-risk features, and complicated. The role of thoracic endovascular aortic repair (TEVAR) in uncomplicated TBAD remains uncertain and is the topic of ongoing clinical trials. In most complicated cases, TEVAR is effective at restoring visceral and extremity blood flow. TEVAR has also been shown to arrest hemorrhage in the setting of thoracic aortic rupture. TEVAR has been demonstrated to induce satisfactory remodeling in the covered segment of the thoracic aorta, but progressive enlargement of the visceral aorta has led to a variety of techniques designed to promote remodeling in the uncovered aortic segment. There is a need to better define high-risk features so that treatment can be tailored to specific clinical conditions.

Radiomics-Based Risk Assessment Correlates With Outcomes in Patients With Acute Type B Aortic Dissection Undergoing Thoracic Endovascular Repair

OBJECTIVES

Our study aimed to investigate the correlations between radiomics-based assessment and outcomes, including positive aortic remodeling (PAR), reintervention for dissection at 1 year, and overall survival, in patients with Type B aortic dissection (TBAD) who underwent thoracic endovascular aortic repair (TEVAR).

METHODS

This was a single-center, retrospective, cohort study. The cohort comprised 104 patients who had undergone TEVAR of TBAD in our institution between January 2010 and October 2022. We segmented preoperative computed tomography (CT) images of the patients' descending aorta regions, then extracted a comprehensive set of radiomic features, including first-order features, shape features (2D and 3D), gray-level co-occurrence matrix (GLCM), gray-level size zone matrix, gray-level run length matrix, gray-level dependence matrix, neighborhood gray-tone difference matrix, from the regions of interest. Next, we selected radiomics features associated with total descending aorta positive aortic remodeling (TDA-PAR) and reintervention by least absolute shrinkage and selection operator (LASSO) regression and features associated with survival by LASSO-Cox regression. This enabled us to calculate radiomics-based risk scores for each patient. We then allocated the patients to high and low radiomics-based risk groups, the cutoff being the median score. We used 3 different models to validate the radiomics-based risk scores.

RESULTS

The patients' baseline characteristics did not differ between those who achieved TDA-PAR and those who did not. The radiomics-based risk scores were significantly and independently associated with all 3 outcomes. As to the impact of specific radiomics features, we found that GLSZM_SmallAreaLowGrayLevelEmphasis and shape_Maximum2DDiameterColumn had positive impacts on both reintervention and survival outcomes, whereas GLCM_Idmn positively affected survival but negatively affected reintervention. We found that radiomics-based risk for TDA-PAR correlated most significantly with zone 6 PAR.

CONCLUSIONS

Radiomics-based risk scores were significantly associated with the outcomes of TDA-PAR, reintervention, and overall survival. Radiomics has the potential to make significant contributions to prediction of outcomes in patients with TBAD undergoing TEVAR.

CLINICAL IMPACT

In this study of 104 patients with Type B aortic dissection, we demonstrated associations between radiomics-based risk and postoperative outcomes, including total descending aorta positive aortic remodeling, reintervention and survival. These findings highlight radiomics' potential as a tool for risk stratification and prognostication in acute Type B aortic dissection management.

Changing Management of Type B Aortic Dissections

The purpose of this manuscript is to review recent trends in the management of acute type B aortic dissection. Due to its efficacy and low morbidity, thoracic endografting has rapidly been adopted as the treatment of choice for most patients with malperfusion or rupture as a consequence of acute aortic dissection. This technology is increasingly applied to patients without rupture or malperfusion, so-called "uncomplicated" dissections, to reduce the incidence of late aneurysmal degeneration in the ungrafted segments of the thoracoabdominal aorta. A variety of techniques have been proposed, including intentional rupture of the dissection membrane to obliterate the false lumen as well as the candy-plug technique to eliminate retrograde flow in the false lumen.

Five-year results of the STABLE II study for the endovascular treatment of complicated, acute type B aortic dissection with a composite device design

OBJECTIVE

To provide the five-year outcomes of the use of a composite device (proximal covered stent-graft + distal bare stent) for endovascular repair of patients with acute, type B aortic dissection complicated by aortic rupture and/or malperfusion.

METHODS

STABLE II was a prospective, multicenter study of the Zenith Dissection Endovascular System (William Cook Europe, Denmark). Patients were enrolled between August 2012 and January 2015 at sites in the United States and Japan. Five-year follow-up was completed by January 2020.

RESULTS

In total, 73 patients (mean age 60.7±10.9 years; 65.8% male) with acute type B dissection complicated by malperfusion (72.6%), rupture (21.9%), or both (5.5%) were enrolled. Patients were treated with either a composite device (79.5%) or the proximal stent-graft alone (no distal bare stent, 20.5%). Dissections were more extensive in patients who received the composite device (408.9±121.3 mm) than in patients who did not receive a bare stent (315.9±100.1 mm). Mean follow-up was 1209.4±754.6 days. Freedom from all-cause mortality was 80.3%±4.7% at one year and 68.9%± 7.3% at five years. Freedom from dissection-related mortality remained at 97.1%±2.1% from one-year through five-year follow-up. Within the stent-graft region, the rate of either complete thrombosis or elimination of the false lumen increased over time (82.1% of all patients at five years vs. 55.7% at first post-procedure CT), with a higher rate at five years in patients who received the composite device (90.5%) compared with patients without the bare stent (57.1%). Throughout follow-up, overall true lumen diameter increased within the stent-graft region, and overall false lumen diameter decreased. At five years, 20.7% of patients experienced a decrease in maximum transaortic diameter within the stent-graft region, 17.2% experienced an increase, and 62.1% experienced no change. Distal to the treated segment (but within the dissected aorta), 23.1% of patients experience no change in transaortic diameter at five years; a bare stent was deployed in all these patients at the procedure. Five-year freedom from all secondary intervention was 70.7%±7.2%.

CONCLUSIONS

These five-year outcomes indicate a low rate of dissection-related mortality for the Zenith Dissection Endovascular System in the treatment of patients with acute, complicated type B aortic dissection. Further, these data suggest a positive influence of composite device use on false lumen thrombosis. Continuous monitoring for distal aortic growth is necessary in all patients.

Extended Stent Coverage Decreases Distal Aortic Segmental Enlargement After the Endovascular Repair of Acute Complicated Type B Aortic Dissection: A Multi-Center Retrospective Study of 814 Patients

PURPOSE

This study aimed to investigate the effect of distal aortic segmental enlargement (DASE) after thoracic endovascular aortic repair for complicated type B aortic dissection (cTBAD).

MATERIALS AND METHODS

From March 2003 to October 2018, 814 patients with acute cTBAD from 5 medical centers were retrospectively identified. DASE is indicated as the enlargement of distal aortic segmental volume ≥1.6 fold of the preoperative volume compared with the most recent postoperative computed tomography angiography (CTA) scan. Of these patients, 635 (78%) were identified as non-DASE, and 179 (22%) were identified as DASE. Competing risk analysis was performed to compare late death and distal aortic reintervention between the groups. The morphological variables and false lumen thrombosis at 7 aortic levels were measured based on the preoperative CTA and the most recent CTA. Univariate and multivariate Cox regression analyses were used to assess the independent predictors of DASE.

RESULTS

The mean follow-up time of the entire cohort was 5.6 years (interquartile range: 2.4-8.3 years). There were total of 208 late deaths, including 94 (14.8%) deaths in non-DASE group versus 114 (63.7%) deaths in the DASE group. Distal aortic reintervention was observed in 89 patients, with 43(6.7%) in the non-DASE group versus 46 (25.7%) in the DASE group. The cumulative incidence of late death and distal aortic reintervention were significantly higher in the DASE than in the non-DASE group (p<0.001). In morphological analysis, significant incomplete false lumen thrombosis was observed in all distal aortic segments above the aortic level of celiac artery (p<0.01). According to multivariate analysis, the Marfan syndrome, stent coverage to the level of diaphragm and the level of celiac artery were independent predictors of the DASE (p<0.001). Patients with extended stent coverage to the level of celiac artery have shown a lower incidence of DASE (p<0.010).

CONCLUSION

Compared with the non-DASE group, patients with DASE demonstrated a higher rate of late death and distal aortic reintervention. For the cTBAD population, extended stent-graft coverage to the aortic section between diaphragm and celiac artery might serve as a "cost-efficient" cutoff point aiming to reduce the risk of DASE.

Chronic abdominal aortic dissection, endovascular treatment using a new Stent-graft for in situ Fenestration

Background

Although endovascular treatment of the thoracic aorta (TEVAR) has become an elective procedure for treatment of complicated type B aortic dissection, its role in treating post dissection thoraco-abdominal aortic aneurysm (TAAA), is still limited. This is a case of aortic vascular disease, which reports the use of a new endovascular device.

Case presentation

: We present the case of a 62 year old male patient with a history of hypertension, active smoker, who presented penetrating descending thoracic aortic ulcer in the setting of a chronic abdominal aortic dissection. The patient was treated using a new stent graft capable of in situ fenestration that allowed crossing the stent-graft membrane, implanting a covered stent to exclude the re-entry at the level of the left renal artery and redirecting the blood flow through the true lumen.

Conclusions

This case report demonstrates the feasibility of a novel stent-graft concept. Larger studies with longer follow-up are essential to fully evaluate the safety and effectiveness of this new design.