Midterm results after endovascular treatment of acute, complicated type B aortic dissection

Interventions in Acute or Subacute Phase for Type B Aortic Dissection

The treatment strategy for acute and subacute Stanford type B aortic dissection has changed significantly since the advent of thoracic endovascular aortic repair (TEVAR). Indication for invasive treatment: In addition to the conventional complicated cases (rupture or malperfusion case), the indication for invasive treatment now includes cases with refractory hypertension, persistent or recurrent pain, large aortic diameter, and other conditions that are considered to have a poor prognosis with conservative treatment. Treatment methods: TEVAR is the first choice for acute, subacute, and early chronic-stage treatment, and when this is not possible, other techniques (fenestration and graft replacement) are chosen. Treatment timing: The timing of invasive treatment should be emergent in life-threatening conditions (for rupture or malperfusion case) and immediate in symptomatic cases, while in other cases, preemptive TEVAR is considered appropriate on a scheduled timing within 6 months of onset. (This is a translation of Jpn J Vasc Surg 2023; 32: 157-163.).

Three-dimensional modelling and hemodynamic simulation of the closure of multiple entry tears in type B aortic dissection

BACKGROUND

Stanford type B aortic dissection (TB-AD) is a life-threatening vascular condition with high rates of morbidity and mortality. Currently, thoracic endovascular aortic repair (TEVAR) is widely performed to treat TB-AD, and some studies have analyzed the influence of stents on hemodynamics using computational fluid dynamics (CFD) models. However, the accuracy of TB-AD simulation models are not satisfactory, they are often constructed as a regular ideal model. Furthermore, it is unclear which tear should be closed for the best treatment when there are multi entry tears.

PURPOSE

The aims of this paper were to provide an assessment method for the selection of the surgical closure location for type B aortic dissection. Five 3D models of multiple entry tears in type B aortic dissection were produced using real patient computed tomography (CT) images to perform hemodynamic analyses of flow velocity streamlines, wall pressure, and wall shear stress.

METHODS

A Boolean operation was adopted to establish 3D models with multiple entry tears in type B aortic dissection based on patient-specific CT images. The Mimics and Ansys plug-in The Integrated Computer Engineering and Manufacturing code for Computational Fluid Dynamics (ICEM CFD) software were applied to mesh the 3D models. The flow velocity streamlines, wall pressures, and wall shear stresses were then analyzed in the finite element analysis software Fluent. Five 3D models were produced to compare the hemodynamic characteristics of different entry tear numbers, as well as the changes of different closure positions before and after closure.

RESULTS

The false lumen of the model with two entry tears had a higher wall pressure than that of model with multiple entry tears, which may tend to squeeze the true lumen and expand the false lumen. The load distribution of the vessel in the model with multiple entry tears had a more balanced flow velocity, and its wall pressure and shear stress were lower than that of model with two entry tears. For aortic dissection with two entry tears, the closure of the proximal entry tear was recommended, which helped to isolate and thrombose the false lumen, thereby improving the blood supply function of the true lumen. Because the postoperative vascular flow velocity and mechanical load performance of the vascular wall were still higher than those of normal blood vessels, the postoperative blood vessels remained pathological, and TEVAR did not restore the blood vessels to their original healthy state.

CONCLUSIONS

Type B aortic dissection with two entry tears tend to squeeze the true lumen and expand the false lumen, resulting in a new entry tear and deterioration into multiple entry type B aortic dissection. The model of the vessel with multiple entry tears had a more balanced distribution in flow velocity and a smaller wall pressure and shear stress than that of the vessel with two entry tears. The closure of the proximal entry tear was considered an ideal solution for type B aortic dissection with two entry tears.

MANAGEMENT OF LEFT SUBCLAVIAN ARTERY IN TYPE-B AORTIC DISSECTION TREATED WITH THORACIC ENDOVASCULAR AORTA REPAIR

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) has been the favored approach for the treatment of type B aortic dissection (TBAD). To obtain an adequate proximal landing zone, coverage of the left subclavian artery (LSA) will often be necessary. The occurrence of possible neurologic complications has continued to be debated. We investigated the management of the LSA in patients with TBAD undergoing endovascular repair.

METHODS

We searched the PubMed and MEDLINE databases to October 2020 for studies of TEVAR for TBAD. Data on the study design, demographics, endograft details, LSA coverage and revascularization, mortality, complications, and follow-up were extracted and analyzed. The effects of LSA coverage and revascularization on neurologic complications and outcomes were investigated.

RESULTS

A total of 26 reports (24 retrospective and 2 prospective) were deemed eligible for our study. A total of 1483 patients (mean age, 56.9 ± 6.2 years) had undergone TEVAR for acute (n = 932; 62.9%), subacute (n = 36; 2.4%), or chronic (n = 515; 34.7%) TBAD, with a success rate of 97.8% and hospital mortality of 4.9%. The LSA origin had been covered for 707 patients (47.7%), and 326 had undergone LSA revascularization (surgical, n = 96; endovascular, n = 170; unspecified or not reported, n = 60). LSA revascularization was concomitant for 68.1% of cases, after TEVAR for 1.8%, and not reported for 30.1%. Of 1146 patients, 10 (0.9%) had experienced left arm claudication, and the overall stroke rate was 3.3% (2.7% for the LSA group and 1% for the uncovered LSA group; P = .0815). Of the patients with stroke and a covered LSA, 1% (2 of 203) had undergone LSA revascularization and 4.8% (5 of 105) had not (P = .0478). Twenty-six patients (1.9%) had developed paraplegia: 0.7% (3 of 433) with a covered LSA, 1.4% (7 of 491) with an uncovered LSA (P = .3508), and not reported for 16 patients. Endoleak was present in 138 patients (13.4%) at a mean follow-up of 32.1 ± 25.6 months.

CONCLUSIONS

Our review has shown that LSA coverage during endovascular repair for complicated TBAD will does not significantly increase the risk of neurologic complications; however, revascularization of the LSA should be always recommended.

1-Year Outcomes of a Multicenter Randomized Controlled Trial of the Ankura II Thoracic Endoprosthesis for the Endovascular Treatment of Stanford Type B Aortic Dissections

Background

The Ankura II Thoracic Stent Graft System (Lifetech, Shenzhen, China) is an evolution of the Ankura stent graft. This study reports one-year outcomes of the Ankura II Thoracic Stent Graft System for endovascular treatment of Stanford type B aortic dissections.

Methods

The Ankura II Thoracic Aortic Endovascular Trial was a randomized, single-blinded, clinical trial conducted at 12 Chinese institutes. The enrolled patients diagnosed with Stanford type B aortic dissections (TBADs) were randomly assigned to the Ankura group or Ankura II group. Standard follow-up examinations were performed at 1, 6, and 12 months. Safety and efficacy data were analyzed.

Results

132 patients with TBADs were enrolled. The outcomes for the primary safety end points revealed that the Ankura II stent graft was statistically non-inferior compared to the Ankura stent graft. The 1-month device-related major adverse events (1.6 vs. 0%; p = 0.48), 1-month all-cause mortality (1.7 vs. 4.5%; p = 0.621), 12-month survival rate (95.2 ± 2.7% vs. 94.1 ± 2.9%; p = 0.769), and major adverse event (MAE) rate (5.1 vs. 4.7% at 1 month; p = 0.73 and 5.8 vs. 8.9% at 12 months; p = 0.718) of Ankura II group are all comparable to Ankura group. The two groups showed similar primary effectiveness and true lumen expansion effect, and false lumen remodeling was improved in Ankura II group (−100.0 vs. −48.5%; p = 0.08).

Conclusions

The one-year outcomes from this prospective, randomized, multicenter study demonstrate that Ankura II stent graft shows comparable results to Ankura for treating TBADs, resulting in low mortality rates, MAEs and reintervention rates.

Clinical Trial Registration

ChiCTR-TRC-12002844.

Endovascular repair of acute complicated type B aortic dissection-systematic review and meta-analysis of long-term survival and reintervention

Background

Thoracic endovascular repair (TEVAR) is considered the first-line therapy in the repair of acute complicated type B aortic dissection (AC-BAD). Given the difficulty of designing randomized trials in this surgical cohort, long-term outcome data is limited. This systematic review and meta-analysis provide a complete aggregation of reported long-term survival and freedom from reintervention of AC-BAD patients based on the existing literature.

Methods

Three databases were searched from date of database inception to January 2021. The relevant references were identified and baseline cohort characteristics, survival and freedom from reintervention were extracted. The primary endpoints were survival and freedom from reintervention, whilst secondary endpoints were post-operative outcomes such as cord ischemia and endoleak. Kaplan-Meier curves were digitized and aggregated as per established procedure.

Results

A total of 2,812 references were identified in the literature search for review, with 46 selected for inclusion. A total of 2,565 patients were identified, of which 1,920 (75%) were male. The mean age of the cohort was 59.8±5.8. Actuarial survival at 2, 4, 6 and 10 years was 87.5%, 83.2%, 78.5% and 69.7%, respectively. Freedom from all secondary reintervention at 2, 4, 6, 8 and 10 years was 74.7%, 69.1%, 65.7%, 63.9% and 60.9%, respectively. When accounting for study quality, actuarial survival at 2, 4, 6 and 8 years was 85.4%, 79.1%, 69.8% and 63.1%, respectively. Freedom from all secondary reintervention at 2, 4, 6 and 8 years was 73.2%, 67.6%, 63.7% (maintained), respectively.

Conclusions

TEVAR is associated with promising long-term survival extended to 10 years, though rates of freedom from reintervention remain an ongoing point for improvement. Randomized controlled trials comparing endovascular with open repair in the setting of acute, complicated type B aortic dissection are needed.

Endograft exclusion of the false lumen restores local hemodynamics in a model of type B aortic dissection

OBJECTIVE

Endovascular intervention in uncomplicated type B dissection has not been shown conclusively to confer benefit on patients. The hemodynamic effect of primary entry tear coverage is not known. Endovascular stent grafts were deployed in a model of aortic dissection with multiple fenestrations to study these effects. It is hypothesized that endograft deployment will lead to restoration of parabolic true lumen flow as well as elimination of false lumen flow and transluminal jets and vortices locally while maintaining distal false lumen canalization.

METHODS

Thoracic stent grafts were placed in silicone models of aortic dissection with a compliant and mobile intimal flap and installed in a flow loop. Pulsatile fluid flow was established with a custom positive displacement pump, and the models were imaged by four-dimensional flow magnetic resonance imaging. Full flow fields were acquired in the models, and velocities were extracted to calculate flow rates, reverse flow indices, and oscillatory shear index, the last two of which are measures of stagnant and disturbed flows.

RESULTS

Complete obliteration of the false lumen was achieved in grafted aorta, with normal parabolic flow profiles in the true lumen (maximal velocity, 30.4 ± 8.4 cm/s). A blind false lumen pouch was created distal to this with low-velocity (5.8 ± 2.7 cm/s) and highly reversed (27.9% ± 13.9% reverse flow index) flows. In distal free false lumen segments, flows were comparable to ungrafted conditions with maximal velocities on the order of 7.0 ± 2.1 cm/s. Visualization studies revealed forward flow in these regions with left-handed vortices from true to false lumen. Shear calculations in free false lumen regions demonstrated reduced oscillatory shear index.

CONCLUSIONS

Per the initial hypothesis, endovascular grafting improved true lumen hemodynamics in the grafted region. Just distally, a prothrombotic flow regimen was noted in the false lumen, yet free false lumen distal to this remained canalized. Clinically, this suggests a need for advancing endovascular intervention beyond sole entry tear coverage to prevent further false lumen canalization through uncovered fenestrations.

The Year in Vascular Anesthesia: Selected Highlights From 2018

This special article is the second in an annual series for the Journal of Cardiothoracic and Vascular Anesthesia that is specifically dedicated to highlights in vascular anesthesiology published in 2018. This review begins with 2 updates in preoperative medicine in the vascular surgery population, including recent publications regarding the management of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers and antiplatelet medications in the perioperative period. The next section focuses on complications related to thoracic endovascular aortic surgery, particularly as technology advances allow for endovascular repair of more complex anatomy. The final section focuses on quality in vascular surgery and evaluates recent publications that examine the safety and feasibility of fast-track endovascular aortic surgery. Even though this is only a sampling of the literature published in 2018 relevant to the cardiovascular anesthesiologist, these themes represent some of the topics most clinically relevant to the perioperative period.

Acute medical management of aortic dissection

Acute aortic dissection is a life-threatening disease. Current therapeutic guidelines recommend medical therapy with aggressive blood pressure lowering for patients with acute aortic dissection, when they are not indicated for emergency surgery. In particular, patients with aortic dissection without ascending aorta involvement (Stanford type B) are treated medically, unless they have fatal complications. Patients with type B aortic dissection who have critical complications have higher early mortality than that in patients without complications. However, recent advances in thoracic endovascular aortic repair can improve the clinical outcomes in such patients. Accordingly, current guidelines recommend thoracic endovascular aortic repair for patients with complicated type B aortic dissection. However, patients with visceral ischemia still have a poor prognosis, even when they are treated with thoracic endovascular aortic repair; an early diagnosis and intervention is crucial to prevent mortality. Understanding the pathophysiological anatomy that can induce organ malperfusion might be important for an early diagnosis and intervention. This review summarizes the current state of acute medical management in patients with acute aortic dissection, based on current evidence and expert consensus, focusing on patients with type B aortic dissection.

Update on the Therapeutic Strategy of Type B Aortic Dissection

Stanford type B aortic dissection (TBAD) is a life-threatening disease. Current therapeutic guidelines recommend medical therapy with aggressive blood pressure lowering for patients with acute TBAD unless they have fatal complications. Although patients with uncomplicated TBAD have relatively low early mortality, aorta-related adverse events during the chronic phase worsen the long-term clinical outcome. Recent advances in thoracic endovascular aortic repair (TEVAR) can improve clinical outcomes in patients with both complicated and uncomplicated TBAD. According to present guidelines, complicated TBAD patients are recommended for TEVAR. However, the indication in uncomplicated TBAD remains controversial. Recent results of randomized trials, which compared the clinical outcome in patients treated with optimal medical therapy and those treated with TEVAR, suggest that preemptive TEVAR should be considered in uncomplicated TBAD with suitable aortic anatomy. However, these trials failed to show improvement in early mortality in patients treated with TEVAR compared with patients treated with optimal medical therapy, which suggest the importance of patient selection for TEVAR. Several clinical and imaging-related risk factors have been shown to be associated with early disease progression. Preemptive TEVAR might be beneficial and should be considered for high-risk patients with uncomplicated TBAD. However, an interdisciplinary consensus has not been established for the definition of patients at high-risk of TBAD, and it should be confirmed by experts including physicians, radiologists, interventionalists, and vascular surgeons. This review summarizes the current understanding of the therapeutic strategy in patients with TBAD based on evidence and expert consensus.

Treatment of serious complications following endovascular aortic repair for type B thoracic aortic dissection

Objective

This study aimed to describe treatment of serious complications after primary thoracic endovascular aortic repair (TEVAR) in type B aortic dissection.

Methods

From June 2008 to March 2016, serious complications occurred in 58 patients without Marfan syndrome who received TEVAR for type B aortic dissection.

Results

Complications included endoleak, distal true lumen collapse, retrograde dissection, stroke, stent–graft (SG) migration and mistaken deployment, lower limb ischaemia, and SG fracture. Treatment included endovascular repair, surgical procedures, or conservative medication. Forty-six patients recovered from complications. Twelve patients were not cured. The median follow-up time was 29.5 months (2–61 months). The overall 30-day mortality rate was 1.7% (1/58) and the total mortality rate following secondary complications was 8.6% (5/58). The causes of death were stroke and aortic rupture.

Conclusion

Some treatments need to be performed after TEVAR because of severe complications. A reduction in these complications can be achieved by optimal evaluation of patients, selection of SGs, and specialized endovascular manipulation.

Influence of distal entry tears in acute type B aortic dissection after thoracic endovascular aortic repair

OBJECTIVE

This study evaluated the clinical influence of distal entry tears in acute type B aortic dissection (ATBAD) after thoracic endovascular aortic repair (TEVAR).

METHODS

From August 2009 to December 2014, the clinical outcomes of 130 patients who underwent TEVAR for ATBAD were retrospectively analyzed. According to whether distal entry tears existed after TEVAR, patients were divided into group A (n = 25, absence of distal entry tears) and group B (n = 105, presence of distal entry tears). We evaluated clinical outcomes, including mortality and morbidity in early and late follow-up, as well as aortic remolding. Late aortic events were defined as aortic dissection-related events occurring >30 days from the initial TEVAR procedures, which consisted of endoleak, retrograde type A aortic dissection, aortic enlargement, late rupture, repeat dissection, and stent-induced new entry tear.

RESULTS

The study comprised 130 patients (114 men [87.7%] and 16 women [12.3%)] with a mean age of 53.71 years. The 30-day mortality was 3.1%, and early morbidity included type I endoleak, 3.1%, organ failure, 3.8%; stroke, 3.1%; spinal cord ischemia, 0%; and early rupture 1.5%. The overall survival rate by Kaplan-Meier analysis at 1, 3, and 5 years was 93.8%, 89.5%, and 79.2%, respectively. There were no significant differences in early morbidity and 30-day mortality and late survival between group A and group B. However, group A had a significantly lower rate of late aortic events than group B (P = .028 by log-rank test). Meanwhile, group A had better aortic remolding than group B in complete thrombosis of the thoracic aorta at 12 months postoperatively (100% vs 83.5%; P = .029).

CONCLUSIONS

This study demonstrated that TEVAR for ATBAD had low perioperative morbidity and mortality and satisfactory midterm outcome. Distal entry tears increase the occurrence of late aortic events and inhibit aortic remolding but do not have a significantly negative effect on late survival. Repairing all entry tears to restore single-lumen blood flow and enhance false lumen thrombosis might benefit selected patients.

Rapid Aneurysmal Sac Expansion Following Endovascular Repair of a Dissecting Thoracoabdominal Aneurysm

Endovascular repair of dissecting thoracoabdominal aneurysms (TAAA) is challenging and often requires multiple procedures. A 61-year-old man with a dissecting type-II TAAA treated first by placement of a thoracic endograft, and subsequently implantation of a fenestrated endograft. Six months postoperatively, a 10-mm increase of the aorta was observed. A reentry tear in left external iliac artery (EIA) was perfusing the false lumen in a retrograde fashion connecting with the endoleak caused by the inferior mesenteric artery and lumbar arteries. False lumen embolization of the left EIA and outflow vessels was performed. Thrombosis and rapid decrease of false lumen diameter was then observed. This case illustrates the complexity of endovascular management of extensive chronic aortic dissections.

The Potential of Computational Fluid Dynamics Simulation on Serial Monitoring of Hemodynamic Change in Type B Aortic Dissection

PURPOSE

We aimed to assess the potential of computational fluid dynamics simulation (CFD) in detecting changes in pressure and flow velocity in response to morphological changes in type B aortic dissection.

MATERIALS AND METHODS

Pressure and velocity in four morphological models of type B aortic dissection before and after closure of the entry tear were calculated with CFD and analyzed for changes among the different scenarios. The control model (Model 1) was patient specific and built from the DICOM data of CTA, which bore one entry tear and three re-entry tears. Models 2-4 were modifications of Model 1, with two re-entry tears less in Model 2, one re-entry tear more in Model 3, and a larger entry tear in Model 4.

RESULTS

The pressure and velocity pertaining to each of the morphological models were unique. Changes in pressure and velocity findings were accountable by the changes in morphological features of the different models. There was no blood flow in the false lumen across the entry tear after its closure, the blood flow direction across the re-entry tears was reversed after closure of the entry tear.

CONCLUSION

CFD simulation is probably useful to detect hemodynamic changes in the true and false lumens of type B aortic dissection in response to morphological changes, it may potentially be developed into a non-invasive and patient-specific tool for serial monitoring of hemodynamic changes of type B aortic dissection before and after treatment.

Influence of distal extension of false lumen on adverse aortic events after TEVAR in patients with acute type B aortic dissection

OBJECTIVE

To investigate the clinical outcomes influenced by distal extension of false lumen in acute type B aortic dissection (TBAD) patients following thoracic endovascular aortic repair (TEVAR).

METHODS

From April 2002 to January 2013, 264 TBAD patients treated with TEVAR were retrospectively enrolled. The IIIa group exhibited a distal false lumen above the diaphragm (n = 70), and the IIIb group exhibited a distal false lumen under the diaphragm (n = 194). The morphological characteristics and adverse events (30-day and >30 days) were recorded and evaluated.

RESULTS

There were no significant differences between the two groups regarding the demographics, comorbidity profiles, or initial feature of computed tomography angiography. The incidence of true lumen compression and branch involvement were significantly increased in the IIIb group compared with the IIIa group (8.6% vs. 25.3%, respectively; 15.7% vs. 36.1%, respectively, both P < 0.05). The 30-day mortality rate was 1.0% (2/194) in the IIIb group, whereas the IIIa group was zero. The incidence of early adverse events, the 5-year cumulative freedom from adverse events, and the 5-year cumulative freedom from all-cause mortality rate were not significantly different between the IIIa and IIIb groups (2.9% vs. 6.7%, 81.4%, and 80.4%, and 95.7% vs. 93.8%, respectively, all P > 0.05). Log-rank tests also indicated there was no significant difference.

CONCLUSIONS

There was no significant difference between the IIIa and IIIb groups in the 5-year morality and adverse aortic events following TEVAR. The distal extension of false lumen prior to TEVAR does not influence the long-term morality and adverse aortic events in acute TBAD.

Current Treatment Strategies for Acute Type B Aortic Dissection

Acute type B aortic dissection (ATBAD) is a medical emergency that is a common occurrence in patients with atherosclerotic disease. The presentation is usually severe, with tearing pain that radiates to the back, and various levels of end-organ ischemia and malperfusion, even rupture, may occur. Everyone agrees that prompt and aggressive blood pressure control with β-blockers and nitroprusside is imperative, but when to surgically intervene is still not well characterized. However, the advent of minimally invasive stent graft placement has reshaped our thoughts regarding therapeutic intervention for ATBAD. This review is an attempt to define the current surgical indications for treating ATBAD.

Emergency endovascular stent grafting in acute complicated type B dissection

OBJECTIVE

The objective of this study was to assess midterm results of emergency endovascular stent grafting for patients with life-threatening complications of acute type B aortic dissection.

METHODS

Between March 1999 and November 2011, 110 patients (86 men, 24 women) with complications of acute type B aortic dissection (mean age, 61 years; range, 19-87 years) were treated with thoracic endovascular aortic repair for malperfusion (55.5%) or aortic rupture (53.6%) in five major European referral centers and one U.S. referral center. Additional comorbidities included hypertension in 90 patients (82%), diabetes in 14 patients (13%), and chronic obstructive pulmonary disease in six patients (6%). Eleven patients (10%) had undergone previous aortic surgery.

RESULTS

Overall hospital mortality was 12% (n = 13), with 14 late deaths after hospital discharge. In-hospital complications occurred in 32 patients (36%); 10 patients developed postoperative renal failure, five patients experienced new permanent neurologic symptoms, and six patients (5.4%) experienced retrograde type A aortic dissection. Furthermore, nine patients (8%) developed an early type I endoleak. Actuarial survival at 1 and 5 years was 85% and 73%, respectively. Postprocedural computed tomography angiography showed complete or partial thrombosis of the false lumen at the stent graft level in 61% and 23% of all patients, respectively. Freedom from treatment failure according to the Stanford classification was 82%, 75%, and 59% at 1, 3, and 5 years.

CONCLUSIONS

Endovascular repair of complicated acute type B aortic dissection is proven to be a technically feasible and effective treatment modality in this relatively difficult patient cohort. Short-term and midterm results are persuasive; however, the long-term efficacy needs to be further evaluated.

Best surgical option for arch extension of type B dissection: the endovascular approach

Despite advances in surgical techniques and postoperative management, the in-hospital mortality rate for patients undergoing conventional open surgical repair for type B dissections is still significant. In light of this, the less invasive surgical procedure for acute type B aortic dissections, defined as thoracic endovascular aortic repair (TEVAR), was developed. Despite some controversy, the use of TEVAR for the management of type B aortic dissections has become commonplace. Generally, the main entry tear in type B aortic dissection is located in the vicinity of the orifice of the left subclavian artery (LSA). The proximal landing zone in the aortic arch must be secured as long as the aim of TEVAR for type B dissection is primary entry closure. This requires hybrid surgery that includes the use of open surgical procedures, such as debranching for revascularization of cervical branches. Despite the presence of challenging anatomic conditions in the aortic arch, hybrid repair has evolved as an increasingly viable alternative, and promising early and long-term results have been reported. As the next step, fenestrated and branched TEVAR techniques have recently been reported with satisfactory early results. In the coming years, there will be intense competition to develop the devices themselves, improve delivery systems, and supplement devices with auxiliary functions. Thus there is high expectations for the next generation and how they will improve and advance treatment methods of TEVAR for type B aortic dissections.

Endovascular repair of acute uncomplicated aortic type B dissection promotes aortic remodelling: 1 year results of the ADSORB trial

OBJECTIVES

Uncomplicated acute type B aortic dissection (AD) treated conservatively has a 10% 30-day mortality and up to 25% need intervention within 4 years. In complicated AD, stent grafts have been encouraging. The aim of the present prospective randomised trial was to compare best medical treatment (BMT) with BMT and Gore TAG stent graft in patients with uncomplicated AD. The primary endpoint was a combination of incomplete/no false lumen thrombosis, aortic dilatation, or aortic rupture at 1 year.

METHODS

The AD history had to be less than 14 days, and exclusion criteria were rupture, impending rupture, malperfusion. Of the 61 patients randomised, 80% were DeBakey type IIIB.

RESULTS

Thirty-one patients were randomised to the BMT group and 30 to the BMT+TAG group. Mean age was 63 years for both groups. The left subclavian artery was completely covered in 47% and in part in 17% of the cases. During the first 30 days, no deaths occurred in either group, but there were three crossovers from the BMT to the BMT+TAG group, all due to progression of disease within 1 week. There were two withdrawals from the BMT+TAG group. At the 1-year follow up there had been another two failures in the BMT group: one malperfusion and one aneurysm formation (p = .056 for all). One death occurred in the BMT+TAG group. For the overall endpoint BMT+TAG was significantly different from BMT only (p < .001). Incomplete false lumen thrombosis, was found in 13 (43%) of the TAG+BMT group and 30 (97%) of the BMT group (p < .001). The false lumen reduced in size in the BMT+TAG group (p < .001) whereas in the BMT group it increased. The true lumen increased in the BMT+TAG (p < .001) whereas in the BMT group it remained unchanged. The overall transverse diameter was the same at the beginning and after 1 year in the BMT group (42.1 mm), but in the BMT+TAG it decreased (38.8 mm; p = .062).

CONCLUSIONS

Uncomplicated AD can be safely treated with the Gore TAG device. Remodelling with thrombosis of the false lumen and reduction of its diameter is induced by the stent graft, but long term results are needed.

Stent graft therapy for false lumen aneurysmal degeneration in established type B aortic dissection (FADED) results in differential volumetric remodeling of the thoracic versus abdominal aortic segments

BACKGROUND

Despite optimal medical therapy of type B aortic dissections, false lumen aneurysmal degeneration of these established dissections (FADED) occur over long term (>6 months). The efficacy of thoracic stent grafts (thoracic endovascular aortic repair [TEVAR]) in promoting aortic remodeling when placed at late time points remains controversial and was the focus of this investigation.

METHODS

Utilizing tomographic scans, the volume of 6 distinct aortic compartments were calculated including the stented true lumen and stented false lumen (STL and SFL), below-stent true and false lumens (BSTL and BSFL), and the infrarenal aorta true and false lumens (IRA TL and IRA FL) when applicable. Cross-sectional areas were calculated at 1-cm intervals, collated, and volumetric ratios were derived from preoperative values.

RESULTS

From 2004 to 2011, 21 patients met inclusion criteria. Complete false lumen (FL) thrombosis was achieved in 85.7% of SFL and 26.3% of BSFL. Volumetric analysis demonstrated that 71% of patients had increased STL volume and 71% had decreased SFL. In the below-stent region, 75% of patients had increased true lumen (TL) with 59% concurrently decreased FL volume. The IRA TL volume increased in 85% of patients and the IRA FL also expanded in 75% of this cohort. At the latest time point, overall growth was noted in the infrarenal aortic segment.

CONCLUSIONS

Utilization of TEVAR in patients suffering from FADED can promote TL expansion with concurrent FL regression; however, progressive dilation in the total infrarenal aorta volume may occur and warrants close surveillance.

Prognostic factors in patients with uncomplicated acute type B aortic dissection

BACKGROUND

The benefit of thoracic endovascular aortic repair (TEVAR) for uncomplicated acute type B aortic dissection is unclear. Reliable prognostic factors are needed to identify candidates for prophylactic TEVAR. The aim of this study was to detect prognostic factors in patients with uncomplicated acute type B aortic dissection.

METHODS

From January 2003 to April 2012, a total of 228 patients with uncomplicated acute type B aortic dissection were admitted to our institute. Cox proportional hazards analysis was performed to identify risk factors for death, dissection-related death, and aortic events.

RESULTS

Independent predictors of mortality were age (hazard ratio [HR], 1.08; p < 0.001) and false lumen thickness (mm) (HR, 1.10; p = 0.013), and the risk factor for dissection-related death was false lumen thickness (mm) (HR, 1.14; p < 0.001). Independent risk factors for aortic events were diameter of the descending aorta (mm) (HR, 1.14; p < 0.001) and entry in a proximal site (HR, 2.90; p = 0.02). The actuarial freedom from aortic events in patients with a descending aortic diameter of less than 40 mm and no entry in a proximal site at 1, 3, and 5 years was 96.6%, 90.8%, and 82.5%, respectively, whereas in patients with 1 of these 2 factors, it was 80.1%, 66.8%, and 53.5%, respectively.

CONCLUSIONS

In uncomplicated acute type B aortic dissection, the diameter of the descending aorta and entry in a proximal site were independent prognostic factors for aortic events. Prophylactic TEVAR should be considered for patients with these risk factors.

Treatment of acute type-B aortic dissection: thoracic endovascular aortic repair or medical management alone?

OBJECTIVES

This study sought to evaluate the early and long-term effect of thoracic endovascular aortic repair (TEVAR) on type-B acute aortic dissection (AAD).

BACKGROUND

Uncomplicated type-B AAD is generally treated with medical management; complicated dissections require surgery or TEVAR. Studies have demonstrated that long-term outcomes with medical management are suboptimal. Therefore, we sought to determine the long-term effect of TEVAR compared with medical management alone on type-B AAD.

METHODS

From January 2004 to May 2008, 193 consecutive patients in 2 hospitals were treated and retrospectively placed into 1 of 2 groups: 1) the TEVAR group-type-B AAD treated with TEVAR and antihypertensive medications (n = 152); and the 2) medicine group-uncomplicated type-B AAD treated medically alone (n = 41). All TEVAR procedures were performed in the acute phase.

RESULTS

There were no significant differences in demographics, comorbidity profiles, or early events between groups. The cumulative freedom from all late adverse events at 1, 3, and 5 years was 97%, 89%, and 67% in the TEVAR group and 97%, 63%, and 34% in the medicine group. Log-rank tests showed that medically treated patients had more late adverse events than TEVAR-treated patients did (p = 0.003). The 5-year cumulative survival rate from all-cause death was not significantly different between the 2 groups.

CONCLUSIONS

Patients with type-B AAD treated with TEVAR experienced fewer late adverse events than those treated with medical management, but there was no significant difference among the groups in 5-year mortality rates. Further studies of longer-term survival rates are needed to determine whether TEVAR could be an effective treatment for type-B AAD.

Role of the femorofemoral crossover graft in acute lower limb ischemia due to acute type B aortic dissection

Acute limb ischemia due to type B aortic dissection is rare and continues to be a management challenge. A case series is presented here with the aim of assessing the outcomes of treatment with a femorofemoral crossover graft with or without thoracic stent graft insertion. This is a combined retrospective and prospective review of nine cases of acute lower limb ischemia secondary to acute type B aortic dissection. The presenting features, radiological findings, treatment and outcomes were reviewed. Five patients had a femorofemoral crossover graft (FFXO) alone, two an FFXO with a thoracic stent graft and the eighth a thoracic and iliac stent. The other case was initially treated conservatively but subsequently required an FFXO. The mean follow-up was 16 (3-51) months. A further two thoracic stents were placed during the follow-up period. Thus five out of nine patients (56%) required aortic stenting. This series suggests that an FFXO is a reliable treatment for acute limb ischemia due to type B aortic dissection. However, these patients are often complex with ischemia in other vascular beds and are at risk of subsequent aneurysmal dilation.

Early malperfusion, ischemia reperfusion injury, and respiratory failure in acute complicated type B aortic dissection after thoracic endovascular repair

BACKGROUND

The aim of this study was to determine the early mortality and major complications of acute complicated type B aortic dissection (ACBD) after thoracic endovascular aortic repair (TEVAR).

METHODS

Twenty-six consecutive patients with ACBD who underwent TEVAR were included. Clinical indications before TEVAR and in-hospital mortality and major complications after TEVAR were analyzed and compared with similar reports.

RESULTS

TEVAR was technically successful in all cases. In-hospital mortality occurred in four patients (15%), and major complications occurred in an additional four patients (15%). Three of the four (75%) of the deaths were associated with malperfusion and ischemia reperfusion injury (IRI), and 3/4 (75%) of the major complications were caused by respiratory failure (RF).

CONCLUSIONS

In-hospital mortality associated strongly with severe end-organ malperfusion and IRI, while major complications associated with RF, during TEVAR. Our results indicate that malperfusion, IRI and respiratory failure during TEVAR should be carefully monitored and aggressively treated.