Mid- and long-term outcomes of thoracic endovascular aortic repair in acute and subacute uncomplicated type B aortic dissection

Uncomplicated Type B Aortic Dissection: A European Multicentre Cross-Sectional Evaluation

BACKGROUND

A multicentre European randomized control trial - European Uncomplicated Type B Aortic Repair (EU-TBAR) is being developed to compare pre-emptive thoracic endovascular aortic repair (TEVAR) with custom-made devices versus conventional optimal medical therapy. The pretrial set-up is confluent on different pillars, including evaluation of 1) European activity, trends, and governance; 2) outcome reporting; and 3) cost evaluation. This article aimed to demonstrate the observational cross-sectional survey results from participating centers and highlight the risk assessment, activity, practices, and governance of uncomplicated type B aortic dissection (uTBAD).

METHODS

This observational cross-sectional European survey used a questionnaire that examined the understanding, risk assessment, local governance oversight, and clinical activity of uTBAD. The data were collected and managed using Research Electronic Data Capture (REDCap).

RESULTS

Out of 43 surveyed surgeons, 37 (86%) responded within a month from 14 European countries. Most reported low annual uTBAD encounters, with autumn being the most common season for cases. Pre-emptive TEVAR was recommended by 43.2% of participants, who favored subacute intervention timing. The Gore TAG was the most used TEVAR device, and custom devices were available for 73% of respondents. Risk factors for uTBAD were ranked, with 'Rapid Aortic Enlargement' deemed most critical. A majority of centers had protocols and multidisciplinary teams, with most having readily available radiology services. Only 45.9% had transfer services to specialized centers.

CONCLUSIONS

uTBAD remains a misnomer of a dynamic, ongoing disease process requiring early diagnosis and intervention. Pre-emptive TEVAR in high-risk uTBAD is becoming more common, with encouraging results prompting an expansion of indication criteria to a broader uTBAD population managed conservatively. Nevertheless, further evidence is needed through large randomized controlled trials, mainly European collaboratives, to reach a definitive conclusion on the optimum surgical management of uTBAD.

Pre-Emptive Endovascular Repair for Uncomplicated Type B Dissection - Is This an Option?

Type B aortic dissection (TBAD) primarily affects men aged 60-65 years, with hypertension in over 80% of cases. The gold standard for the treatment of uncomplicated acute TBAD is Best Medical Treatment (BMT), which focused on controlling blood pressure and heart rate. However, Thoracic Endovascular Aortic Repair (TEVAR) has gained attention over the years, especially for complicated TBAD cases, by covering the primary entry tear, lowering false lumen pressure, and promoting aortic remodeling. TBAD can be classified according to the onset of symptoms into acute, subacute and chronic stages, with different intervention implications at each stage. Studies such as the Acute Dissection Stentgraft OR Best Medical Treatment and Investigation of STEnt grafts in Acute Dissection trials have shown the benefits of TEVAR over BMT, particularly in promoting aortic remodeling and reducing long-term aorta-related mortality. However, these trials noted no significant difference in immediate mortality. TEVAR timing is crucial, as early intervention in the acute phase can lead to higher complication rates due to higher intimal fragility. As a result, the subacute phase offers a balance, allowing beneficial remodeling with a lower complication rate.

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.

Initial aortic repair versus medical therapy for early uncomplicated type B dissections

BACKGROUND

Uncomplicated type B aortic dissections was regarded benign and treated with optimal medical therapy (OMT). However, studies showed highly unpredictable of disease progression, which suggested the need of earlier intervention. To search for features associated with worse outcomes with OMT is important due to risk of intervention. We investigated mortality and aortic remodeling between aggressive (OMT and pre-emptive endovascular intervention) and conservative therapy (OMT and necessary operations).

METHODS

Retrospective analysis was performed in acute and subacute uncomplicated type B dissections patients, including typical aortic dissection, intramural hematoma and penetrating atherosclerotic ulcer, diagnosed between June 2005 and May 2021. Patients with Marfan, traumatic, iatrogenic, zone 0 (ascending aorta) involvement, and maximal aortic diameter > 45mm were excluded. Patients are classified according to initial management.

RESULTS

77 and 33 patients in the aggressive and conservative groups were included respectively. There was no differences in baseline clinical and radiological characteristics between them. During mid-term follow-up (median 62.5 months), there was no difference in the mortality but the incidence of 30-day acute kidney injury was significantly higher in aggressive group. Positive aortic remodeling was noted in aggressive group, with development to complete or incomplete false lumen thrombosis (p < 0.01).

CONCLUSION

Aggressive pre-emptive endovascular therapy though has acceptable outcomes and positive aortic remodelling in early uncomplicated type B dissection with maximal aortic diameter ≤ 45mm. However, it could not translate into better mid-term survival than conservative therapy, but with higher risk of 30-day acute kidney injury. Aggressive pre-emptive endovascular intervention should be cautious in these patients.

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.

Trends in utilization, timing, and outcomes of thoracic endovascular repair for type B aortic dissection in the United States

Background

Aortic dissection is the most common acute aortic syndrome in the United States. Type B aortic dissection (TBAD) can be managed medically, through open surgical repair, or with thoracic endovascular repair (TEVAR). The present study sought to assess contemporary trends in the use and timing of TEVAR.

Methods

Adult nonelective TBAD admissions were identified in the 2010 to 2020 Nationwide Readmissions Database. Patients were categorized as medical management (Medical Management), TEVAR at initial hospitalization (Early), or TEVAR during readmission (Delayed). Multivariable models were developed to assess associations with clinical outcomes and resource utilization.

Results

Of 85,753 patients, 8.7% underwent TEVAR at index hospitalization (Early). From 2010 to 2020, the proportion undergoing TEVAR decreased significantly (from 11.3% to 9.6%; nptrend < .001), while the proportion of TEVAR at a subsequent hospitalization increased (from 13.0% to 21.6%; nptrend < .001). Compared to Medical Management, the Early group was younger (median. 63 [interquartile range (IQR), 52-74] years vs 69 [IQR, 57-81] years), and more frequently privately insured (27.7% vs 17.5%; P < .001). Following adjustment, the Early group had a reduced odds of mortality (adjusted odds ratio [aOR], 0.56; 95% confidence interval [CI], 0.48-0.66) and increased hospitalization costs (β = +$50,000; 95% CI, $48,000-$53,000). Among 4267 TEVAR patients with available procedure timing data, 15.7% were categorized as Delayed. The Early and Delayed groups did not differ in terms of demographics. The Delayed group had a decreased likelihood of major adverse events (aOR, 0.50; 95% CI, 0.39-0.64); however, this did not affect 90-day cumulative hospitalization costs (β = +$2700; 95% CI, -$5000-$11,000, ref: Early).

Conclusions

This study suggests changes to TBAD management in both treatment modality and TEVAR timing. Focused analysis on the timing and long-term costs of TEVAR are needed to optimize care delivery.

Growth and remodeling of the dissected membrane in an idealized dissected aorta model

While transitioning from the acute to chronic phase, the wall of a dissected aorta often expands in diameter and adaptations in thickness and microstructure take place in the dissected membrane. Including the mechanisms, leading to these changes, in a computational model is expected to improve the accuracy of predictions of the long-term complications and optimal treatment timing of dissection patients. An idealized dissected wall was modeled to represent the elastin and collagen production and/or degradation imposed by stress- and inflammation-mediated growth and remodeling, using the homogenized constrained mixture theory. As no optimal growth and remodeling parameters have been defined for aortic dissections, a Latin hypercube sampling with 1000 parameter combinations was assessed for four inflammation patterns, with a varying spatial extent (full/local) and temporal evolution (permanent/transient). The dissected membrane thickening and microstructure was considered together with the diameter expansion over a period of 90 days. The highest success rate was found for the transient inflammation patterns, with about 15% of the samples leading to converged solutions after 90 days. Clinically observed thickening rates were found for 2-4% of the transient inflammation samples, which represented median total diameter expansion rates of about 5 mm/year. The dissected membrane microstructure showed an elastin decrease and, in most cases, a collagen increase. In conclusion, the model with the transient inflammation pattern allowed the reproduction of clinically observed dissected membrane thickening rates, diameter expansion rates and adaptations in microstructure, thus providing guidance in reducing the parameter space in growth and remodeling models of aortic dissections.

Aortic Arch Debranching and Thoracic Endovascular Aortic Repair (TEVAR) for Type B Aortic Dissection

BACKGROUND

Since its introduction, thoracic endovascular aortic repair (TEVAR) has revolutionized the treatment of type B aortic dissections (TBADs). However, the proximal aspect of the aortic pathology treated may infringe on the origin of the left subclavian artery or even more proximally. Hence, to ensure durable outcomes, the origin of these vessels needs to be covered, but an extra-anatomical bypass is required to perfuse vital branches, known as aortic arch debranching. This series aims to describe and delineate the disparities of aortic arch debranching during TEVAR for TBAD.

METHODS

A retrospective review and analysis of a multicenter international database was conducted to identify patients with TBAD treated with TEVAR between 2005 and 2021. Data analyzed included patient demographics, disease characteristics, operative characteristics, and postoperative outcomes with follow-up on mortality and reintervention. All statistical analyses were carried out using IBM SPSS 26. Patient survival was calculated using a Kaplan-Meier survival analysis, and a P value of less than 0.05 was considered statistically significant.

RESULTS

A total of 58 patients were included in the analysis, of which 27 (46.6%) presented with complicated disease and 31 were uncomplicated, of which 10 (17.2%) were classed as high risk and 21 (36.2%) low risk. Zone 2 was the most common proximal landing zone for the stent graft. Left subclavian artery bypass was performed selectively (26%), with 1 stroke occurring, likely due to embolic reasons. A further 6 underwent more proximal aortic debranching before TEVAR (10%) and was a significant risk factor for mortality and the number of stents deployed. The overall rates of reintervention and mortality were 17.2% (n = 10) and 29.3% (n = 17).

CONCLUSIONS

Aortic arch debranching and TEVAR for TBAD is associated with significant mortality. Future developments to treat aortic arch pathology could incorporate branched graft devices, eliminating the need for debranching, improving stroke rates, and reducing future reinterventions.

Need for and update on clinical trials for uncomplicated type B aortic dissection

The mainstay of management for uncomplicated type B aortic dissection is currently optimal medical therapy, targeting blood pressure and heart rate, along with serial imaging. There is a paucity of data that informs whether early intervention with thoracic endografting in this group of patients will promote aortic remodeling and better long-term outcomes. Investigations to date, including the Investigation of Stent Grafts in Aortic Dissection (INSTEAD), INSTEAD-XL, and Acute Dissection: Stent Graft or Best Medical Therapy (ADSORB) studies, have compared thoracic endovascular aortic repair (TEVAR) with optimal medical therapy in patients with uncomplicated type B aortic dissection but have not shown a benefit for TEVAR conclusively. We discuss three major new randomized trials, which will recruit concurrently in Scandinavia (the Scandinavian trial of uncomplicated aortic dissection therapy [SUNDAY] trial), in the United States (the IMPRoving outcomes in vascular DisEase - aortic dissection [IMPROVE-AD] trial) and the United Kingdom (the Early aortic repair in patients needing endovascular surgery for type B aortic dissection [EARNEST] trial), which promise to provide conclusive, level 1 evidence to decipher whether early TEVAR in this cohort of patients in beneficial.

Population risk profile analysis of acute uncomplicated type B aortic dissection patients undergoing thoracic endovascular aortic repair

BACKGROUND

Uncomplicated type B aortic dissection (unTBAD) comprises the estimated majority of type B aortic dissection (TBAD), presenting without any of the complications associated with complicated TBAD (coTBAD). Although first-line treatment for coTBAD is thoracic endovascular aortic repair (TEVAR), and despite the fact that TEVAR has proven its safety and effectiveness in the treatment of unTBAD, unTBAD is still being predominantly managed conservatively with medical therapy, with a small proportion of patients being offered TEVAR.

AIMS

The main scope of this review is to highlight the evidence in the literature of the demographic characteristics and associated co-morbidities of unTBAD patients undergoing TEVAR in order to produce a risk stratification system to achieve favourable outcomes.

METHODS

A comprehensive literature search was conducted using multiple electronic databases including PubMed, Ovid, Scopus, and EMBASE.

RESULTS

Multiple demographic characteristics and associated co-morbidities of unTBAD patients affecting TEVAR outcomes were identified, assessed, and investigated, including age, gender, race, genetics, medical conditions, such as hypertension and diabetes, and lifestyle factors such as smoking. Most factors were associated with increased risks of mortality and morbidity, while others, such as race, were identified as being protective against those when it comes to TEVAR.

CONCLUSION

Despite the favourable results yielded by TEVAR in unTBAD, there remains a grey area concerning its management. Thus, it is important to incorporate the demographics and co-morbidities of unTBAD patients' when into clinical judgement when assessing indications for TEVAR intervention to ensure optimum results can be achieved.

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.

Early Versus Delayed Thoracic Endovascular Aortic Repair for Blunt Traumatic Aortic Injury: A Systematic Review and Meta-Analysis

Blunt aortic injury is the second most prevalent cause of patient fatalities post-trauma, closely following head injuries as the leading cause. In recent years, thoracic endovascular aortic repair (TEVAR) has evidently improved survival rates and reduced complications in patients suffering from blunt traumatic aortic injury (BTAI) in comparison to open surgery and non-operative management. It is difficult to characterize the appropriate criteria for the timing of TEVAR, whether early or delayed for BTAI, considering the discrepancies related to timing. Electronic databases, including PubMed, Scopus, the Cochrane Central Register of Controlled Trials (CENTRAL), and Embase, were searched through April 2023. The primary outcomes were short-term mortality and hospital and intensive care unit (ICU) stays. Time to TEVAR, acute respiratory distress syndrome, sepsis, deep vein thrombosis, delayed stroke, and renal failure were also evaluated. We included a total of seven studies, comprising 4177 patients who met the inclusion criteria. Short-term mortality was significantly higher in the early TEVAR group (RR: 1.86; 95% confidence interval (CI); (1.26-2.74); p<0.001; I2=33%). In contrast, the ICU length of stay was significantly shorter in the early group (mean difference: -2.82 days; 95% CI; (-4.09 - -1.56); p<0.0001; I2=55%). There was no significant difference between both groups in the presenting profile or postoperative complications. Patients undergoing delayed TEVAR had markedly lower mortality rates but a longer ICU stay. The need for future studies with more robust designs is imperative to investigate the factors influencing the timing of repair and the associated outcomes.

Acute aortic dissection

Although substantial progress has been made in the prevention, diagnosis, and treatment of acute aortic dissection, it remains a complex cardiovascular event, with a high immediate mortality and substantial morbidity in individuals surviving the acute period. The past decade has allowed a leap forward in understanding the pathophysiology of this disease; the existing classifications have been challenged, and the scientific community moves towards a nomenclature that is likely to unify the current definitions according to morphology and function. The most important pathophysiological pathway, namely the location and extension of the initial intimal tear, which causes a disruption of the media layer of the aortic wall, together with the size of the affected aortic segments, determines whether the patient should undergo emergency surgery, an endovascular intervention, or receive optimal medical treatment. The scientific evidence for the management and follow-up of acute aortic dissection continues to evolve. This Seminar provides a clinically relevant overview of potential prevention, diagnosis, and management of acute aortic dissection, which is the most severe acute aortic syndrome.

Risk Factors Associated with Poor Prognosis in Patients with Stanford Type B Aortic Dissection after Thoracic Endovascular Aortic Repair

BACKGROUND

The aim of the study was to analyze the clinical characteristics of patients with Stanford type B aortic dissection (TBAD) and risk factors for poor prognosis after thoracic endovascular aortic repair (TEVAR).

METHODS

Clinical records for patients with TBAD presenting to a medical center between March 1, 2012 and July 31, 2020 were reviewed. Clinical data including demographics, comorbidities, and postoperative complications were obtained from electronic medical records. Comparative analysis and subgroup analysis were performed. A logistic regression model was used to analyze prognostic factors in patients with TBAD after TEVAR.

RESULTS

TEVAR was performed on all 170 patients with TBAD, and poor prognosis was identified in 28.2% (48/170) of cases. Patients with a poor prognosis were younger (38.5 [32.0, 53.8] years vs. 55.0 [48.0, 62.0] years, P < 0.001), had higher systolic blood pressure (SBP) (138.5 [127.8, 152.8] mm Hg vs. 132.0 [120.8, 145.3] mm Hg, P = 0.013) and more complicated aortic dissection patients (19 [60.4] vs. 71 [41.8], P = 0.029) than those without a poor prognosis. According to the results of binary logic regression analysis, the possibility of a poor prognosis after TEVAR decreased with each 10 years increase in age (odds ratio: 0.464, 95% confidence interval: 0.327-0.658, P < 0.001).

CONCLUSIONS

There is an association between younger age and a poor prognosis after TEVAR in patients with TBAD, with the condition that those with poor prognoses have higher SBP and more complicated cases. In younger patients, postoperative follow-up should be more frequent, and complications should be managed in time.

Driving Technology for Thoracic Endovascular Aortic Repair: An International Analysis of Single-versus Double-Branch RELAY Outcomes

BACKGROUND

The introduction of endovascular aortic arch repair (EAR) represents a paradigm shift in the management of complex arch pathologies usually treated with open surgical repair (OSR). This shift in treatment of aortic arch disease has also been accompanied with a rise in commercial interest in EAR resulting in the development of several endografts. However, the RELAY™ Branched by Terumo Aortic can be considered the prime endograft choice. In this international original study, a retrospective comparative analysis of international prospective outcomes data on the single- and double-branch RELAY stent grafts is provided.

METHODS

International data on EAR procedures carried out from January 2019 to January 2022 using the single- and double-branch RELAY endograft configurations were collected prospectively. Follow-up data were collected at 30 days, 6 months, 12 months, and 24 months postoperatively. Retrospective descriptive analysis, logistic regression, and Kaplan-Meier analysis were performed.

RESULTS

A total of 125 patients were included, out of which 17 (13.6%) received the single-branch RELAY and 108 the double-branch device. In the single-branch group, no mortalities, strokes, or reinterventions were recoded over 24 months of follow-up. The rates of these outcomes were higher in the other group; however, the differences did not reach significance. Target vessel patency was maintained at 100% throughout the study period with the single-branched RELAY. Overall, our Kaplan-Meier analyses proved that both configurations of RELAY Branched yield excellent short- and mid-term survival and freedom from reintervention.

CONCLUSIONS

Our series has clearly demonstrated that EAR using RELAY Branched is a highly efficacious strategy that yields very favorable results which can be considered superior to other EAR devices as well as OSR. Nevertheless, it seems that clinical outcomes with the single-branch RELAY are more optimal than with the double-branch device.

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.

The intervention seasons of thoracic endovascular aortic repair impacted the outcomes for patients with type B aortic dissection

Purpose

The objective of this research was to investigate whether seasonal variations influence the outcomes of type B aortic dissection (TBAD) patients with thoracic endovascular aortic repair (TEVAR).

Patients and methods

From 2003 to 2020, a retrospective cohort study was performed, which included 1,123 TBAD patients who received TEVAR. Medical records were used to gather data on baseline characteristics. Outcomes including all-cause mortality and aortic-related adverse events (ARAEs) were tracked and analyzed.

Results

Of the 1,123 TBAD patients in this study, 308 received TEVAR in spring (27.4%), 240 cases in summer (21.4%), 260 cases in autumn (23.2%), and 315 cases in winter (28.0%). Patients in the autumn group had a significantly lower risk of 1-year mortality than those in the spring group (hazard ratio: 2.66, 95% confidence interval: 1.06-6.67, p = 0.037). Kaplan-Meier curves revealed that patients who underwent TEVAR in autumn had a lower risk of 30-day ARAEs (p = 0.049) and 1-year mortality (p = 0.03) than those in spring.

Conclusion

This study confirmed that TEVAR operated in autumn for TBAD was associated with a lower risk of 30-day ARAEs and 1-year mortality than in spring.

Ethnic & Sex Disparities in Type B Aortic Dissection Patients Undergoing Thoracic Endovascular Aortic Repair: An International Perspective

BACKGROUND

There has been a revolution in the management of type B aortic dissection (TBAD) over the last 2 decades due to the increasing development of endovascular techniques, with the prime example being thoracic endovascular aortic repair (TEVAR). However, many controversies concerning the use of TEVAR in TBAD exist. For instance, there is little available evidence suggesting any differences in demographics, disease characteristics, intervention technicalities, and clinical outcomes between males and females as well as different ethnicities when undergoing TEVAR for TBAD, both in the short and long term. Also, there is no risk prediction model/tool available. The objective of this international study is to describe and delineate the disparities between male and female patients of different ethnicities in terms of demographics, disease and interventional characteristics, and clinical outcomes.

METHODS

Over 17 years a total of 58 TBAD patients were admitted to 2 tertiary vascular centres and treated using TEVAR. Mortality, postoperative complications and reintervention data were recorded for the first 30 days after the procedure as well as during follow-up. Follow-up for all patients lasted until the study endpoint or until a patient's death. Data were analysed retrospectively using IBM SPSS statistical package 26 for Windows.

RESULTS

The mean age was similar between the 2 groups, with the majority of patients in both being Caucasian. More than half of the males had complicated TBAD, while the majority of females were classed as having uncomplicated disease. The most commonly utilized proximal and distal landing zone for the TEVAR stent graft was zone 2 and zone 4, respectively. The mean proximal stent diameter was significantly larger in males compared to females (P = 0.004). The difference in mean distal diameter between the 2 groups was insignificant (P = 0.721). The mean total stent coverage of the thoracic aorta was 251.3 mm in male patients compared to 291.2 mm in females (P = 0.203). A total of 32 patients underwent adjunctive procedures. Seven (17%) of the males had one or more postoperative complications compared to 2 (12%) females. Nine (22%) males underwent a reintervention procedure post TEVAR compared to only 1 (6%) female (P = 0.136). Overall, males had a mortality rate of 24% (n = 10) compared to 41% of females (n = 7) (P = 0.201). Estimated survival of males and females post TEVAR was 80.4 ± 9.6 months and 69.7 ± 14.4 months (P = 0.428). For the total population, the number of stent grafts was inversely correlated with mortality.

CONCLUSIONS

Despite the favourable clinical outcomes achieved by TEVAR in TBAD, there remains a grey area concerning its management. Thus, it is important to perform risk stratification of individual patients using their demographics and comorbidities, particularly scrutinizing patient sex and ethnic origin, when considering intervention for TBAD to achieve optimum results.

Dynamic and Static Vessel Malperfusion as a Consequence of Acute Type B Aortic Dissection

BACKGROUND

Acute type B aortic dissection (TBAD) is relatively uncommon with an estimated incidence of up to 8 cases per 100,000 individuals annually. It can be classified based on presenting clinical and radiological features into complicated and uncomplicated. Following the initial tear, the direction and extent of the dissection flap is unpredictable, possibly propagating proximally or distally. One consequence of a dissection flap is the occurrence of organ malperfusion by occlusion of the origin of the branch vessel. The 2 types of malperfusion in TBAD are static and dynamic, with the latter being the more common mechanism. Thoracic endovascular aortic repair (TEVAR) has demonstrated its high safety and efficacy when used for TBAD and subsequent malperfusion.

AIMS

This original study specifically examines patients diagnosed with acute TBAD and treated with TEVAR at a single vascular unit, focusing on those presenting with organ malperfusion.

METHODS

Over 16 years, 28 TBAD patients were admitted to a single center and treated using TEVAR. After clinical examination, all patients underwent computed tomography of the thorax and abdomen/pelvis to confirm the diagnosis and classify the extent of the dissection proximally and distally. Once diagnosed, patients were transferred to the high dependency unit and started on blood pressure medication. Subsequent computed tomography scans were performed to classify patients, after which TEVAR was performed.

RESULTS

Twenty five patients underwent TEVAR for TBAD, of which 8 (32%) had symptoms of organ malperfusion. The majority of cases presented with hypertension (89%), describing a sudden onset of upper/midthoracic pain. The origin of the left subclavian artery was occluded in 14 (56%) patients with 9 (64%) needing an extra-anatomical bypass. There was only a single mortality due to a posterior circulation stroke 2 days after TEVAR. Median (range) length of coverage of thoracic aorta by the stent-graft was 33 (15-35) cm. The true lumen (TL) perfused the celiac artery in 6/8 malperfusion patients, superior mesenteric artery in 7/8, right renal artery in 6/8, and, conversely, left renal artery in only 2/8.

CONCLUSIONS

Complicated TBADs behave in an unpredictable manner as it seems the propagating intimal flap invariably maintains vital organ perfusion via the TL. Maintenance of abdominal vessels perfusion from the TL following TEVAR is vital to ensuring optimal results.

Cost analysis of thoracic endovascular aortic repair in type B aortic dissection: How much does quality cost?

BACKGROUND

Aortic dissection (AD) is a life-threatening medical emergency that affects an estimated 3-4 people per 100,000 annually, with 40% of cases classified as type B AD (TBAD). TBAD can be further classified as being complicated (co-TBAD) or uncomplicated (un-TBAD) based on the presence or absence of certain features such as malperfusion and rupture. TBAD can be managed conservatively with optimal medical therapy (OMT), or invasively with open surgical repair (OSR) or thoracic endovascular aortic repair (TEVAR), depending on several factors such as type of TBAD and its clinical acuity. The cost-effectiveness, or cost-benefit profile, of these strategies must be given equal consideration. However, TBAD studies featuring cost analyses are limited within the literature. This narrative review aims to address the gap in the literature on cost-effectiveness of TBAD treatments by providing an overview of cost analyses comparing OMT with TEVAR in un-TBAD and TEVAR with OSR in co-TBAD. Another aim is to provide a market analysis of the commercially available TEVAR devices.

METHODS

A comprehensive literature search was performed using several search engines including PubMed, Ovid, Google Scholar, Scopus, and Embase to identify and extract relevant studies.

RESULTS

Several TEVAR devices are available commercially on the global market costing $12,000-19,495. Nevertheless, the Terumo Aortic RELAY® stent graft seems to be the most cost-effective, yielding highly favourable clinical outcomes. Despite the higher initial cost of TEVAR, evidence in the literature strongly suggest that it is superior to OMT for un-TBAD on the long-term. In addition, TEVAR is well established in the literature as being gold-standard repair technique for co-TBAD, replacing OSR by offering a more optimal cost-benefit profile through lower costs and improved results.

CONCLUSIONS

The introduction of TEVAR has revolutionized the field of aortovascular surgery by offering a highly efficacious and long-term cost-effective treatment for TBAD.

The misnomer of uncomplicated type B aortic dissection

BACKGROUND

Acute type B aortic dissection (TBAD) is a rare condition that can be divided into complicated (CoTBAD) and uncomplicated (UnCoTBAD) based on certain presenting clinical and radiological features, with UnCoTBAD constituting the majority of TBAD cases. The classification of TBAD directly affects the treatment pathway taken, however, there remains confusion as to exactly what differentiates complicated from uncomplicated TBAD.

AIMS

The scope of this review is to delineate the literature defining the intervention parameters for UnCoTBAD.

METHODS

A comprehensive literature search was conducted using multiple electronic databases including PubMed, Scopus, and EMBASE to collate and summarize all research evidence on intervention parameters and protocols for UnCoTBAD.

RESULTS

A TBAD without evidence of malperfusion or rupture might be classified as uncomplicated but there remains a subgroup who might exhibit high-risk features. Two clinical features representative of "high risk" are refractory pain and persistent hypertension. First-line treatment for CoTBAD is TEVAR, and whilst this has also proven its safety and effectiveness in UnCoTBAD, it is still being managed conservatively. However, TBAD is a dynamic pathology and a significant proportion of UnCoTBADs can progress to become complicated, thus necessitating more complex intervention. While the "high-risk" UnCoTBAD do benefit the most from TEVAR, yet, the defining parameters are still debatable as this benefit can be extended to a wider UnCoTBAD population.

CONCLUSION

Uncomplicated TBAD remains a misnomer as it is frequently representative of a complex ongoing disease process requiring very close monitoring in a critical care setting. A clear diagnostic pathway may improve decision making following a diagnosis of UnCoTBAD. Choice of treatment still predominantly depends on when an equilibrium might be reached where the risks of TEVAR outweigh the natural history of the dissection in both the short- and long-term.