Endovascular stent-graft treatment for Stanford type A aortic dissection

Endovascular Treatment of Type A Aortic Dissection: A Systematic Review and Meta-Analysis Using Reconstructed Time-to-Event Data

OBJECTIVE

The undisputed gold standard of treatment for type A aortic dissections (TAAD) is open surgery. Anecdotal reports have assessed thoracic endovascular aortic repair (TEVAR) as a last resort for highly selected candidates. The present study aims to evaluate endovascular outcomes in TAAD patients who are unsuitable for open surgery whilst having TEVAR-compatible aortic anatomy.

METHODS

A PRISMA-compliant systematic search of the PubMed, Scopus, and Cochrane databases was performed up to 19 May 2022. Time-to-event data were reconstructed using Kaplan-Meier curves from the source literature.

RESULTS

In 20 eligible studies, 311 patients underwent TEVAR for acute, subacute, or chronic TAAD. Mean age at the time of the operation was 60.70 ± 8.00 years and 75.48% (95% Confidence Interval [CI], 60.33-88.46%) of the included patients were males. Mean operative time was 169.40 ± 30.70 min. Overall, 0.44% (95% CI, 0.00-4.83%) of the cases were converted to salvage open surgery. Technical failure, stroke, and endoleaks occurred in 0.22%, 0.1%, and 8.52% of the cohort, respectively. Thirty-day postoperative complication rate was 7.08% (95% CI, 1.52-14.97%), whereas late complications developed in 16.89% (95% CI, 7.75-27.88%) of the patients. One-, three-, and five-year survival rates were estimated at 87.15%, 82.52% and 82.31%, respectively. Reintervention was required in 8.38% of the cohort over a mean follow-up of 32.40 ± 24.40 months.

CONCLUSIONS

TEVAR seems to be feasible in highly selected patients with TAAD who cannot tolerate open surgery. Overcoming technical limitations and acquiring long-term data are warranted to safely define the place of endovascular treatment in the armamentarium of TAAD repair.

Feasibility and safety of Stanford A aortic dissection complete endovascular repair system in a porcine model

BACKGROUND

Acute type A aortic dissection (ATAAD) is a catastrophic disease with high morbidity and mortality. Although open surgery is still the gold standard for the treatment of ATAAD, some patients, with advanced age and multiple comorbidities, can only receive medical management alone. Nowadays, thoracic aortic endovascular repair (TEVAR) provides a potential treatment option for the patient with ATAAD, but traditional stent grafts (SGs), which are not designed for the ATAAD, are inapplicable to the unique anatomy of the aortic arch. Therefore, we innovatively created the BRIDGE system (Chuangxin Medical, Shenzhen, China), a complete endovascular reconstruction system designed to treat ATAAD. This study aimed to evaluate the feasibility and safety of the novel Stanford A aortic dissection complete endovascular reconstruction system in a porcine model.

METHOD

The BRIDGE system consists of the type A stent system and the type C stent system. Between November 2020 and March 2021, three white swine were utilized in the study. The BRIDGE system was deployed via the transcatheter approach under angiographic guidance. The swine(n = 3) treated with our system were evaluated using angiography before sacrifice 1-month after implantation, which was followed by gross specimen evaluation and histological examination of harvested tissues.

RESULT

The acute procedure success rate was 100% (3/3). The immediate post-procedural angiography showed that both type A SGs and type C SGs were deployed in satisfactory locations, with patency of the supra-aortic trunk and no endoleak. The cumulative mortality of 30-day was 0% without any adverse events. No device migration or leakage was observed angiographically, before sacrifice. The gross observation confirmed a type A SG covered part of the entry of anonyma. Favorable endothelialization, no thrombogenesis, and slight inflammatory infiltration of the tissues around the device were confirmed by microscopic examinations in all pigs.

CONCLUSION

It was feasible and secure to use Stanford A aortic dissection complete endovascular reconstruction system to implement a transcatheter endovascular repair in a porcine model. With this novel system, treating acute type A aortic dissection may be more efficient and secure in human.

Complete zone 0-10 aortic endovascular reconstruction

To the best of our knowledge, the present report is the first on the safety and efficacy of complete endovascular aortic reconstruction from zone 0 to 10 using a standardized approach and parallel stent graft configurations in high-risk patients considered unfit for surgery. During a 7-year period, five patients with complex thoracoabdominal aortic aneurysms and dissections involving zone 0-10 presented with rupture (n = 1; 20%), were symptomatic (n = 2; 40%), or had an aortic pseudoaneurysm (n = 2; 40%) and underwent complete endovascular zone 0-10 reconstruction using off-the-shelf stent grafts in parallel configurations that included chimneys, periscopes, and endovascular docking stations. The zone 0-5 complete arch chimney thoracic endovascular repair included chimneys that extended from the ascending thoracic aorta to the innominate, left common carotid, and left subclavian arteries and a thoracic stent graft extending from zone 0 to 5. The zone 5-10 aortic reconstructions were staged. Stage 1 included either thoracic stent graft and antegrade four visceral chimney placement or abdominal aortic stent graft and retrograde four visceral chimney placement. Stage II included completion of the remainder of the aortic reconstruction with cerebrospinal fluid drainage. A total of 15 aortic procedures included 34 chimneys (14 aortic arch and 20 visceral). Two patients (40%) underwent zone 0-5 aortic reconstruction first, and three patients (60%) underwent zone 5-10 aortic reconstruction first. The incidence of 30-day mortality, spinal cord ischemia, myocardial infarction, stroke, and visceral ischemia was 0%. At a mean follow-up of 4.5 ± 3.1 years, the aortic reconstruction-related mortality was 0%. All-cause mortality was 20%; one patient had died of pneumonia at 3 years postoperatively. Two endoleaks each occurred in zone 0-5 and zone 5-10 (40% for both groups). All endoleaks were treated with coil embolization. Complete endovascular zone 0-10 aortic reconstruction using parallel stent grafts with a docking station is a feasible and relatively safe technique that offers the ability to customize off-the-shelf devices for the treatment of high-risk patients with limited morbidity and mortality.

Acute aortic dissection: evidence, uncertainties, and future therapies

Remarkable progress has become especially apparent in aortic medicine in the last few decades, leading to essential changes in how thoracic aortic dissection is understood and treated. This state-of-the-art review article addresses the mechanisms of acute aortic dissection, explaining the role of its primary entry location, proximal, and distal dissection extension in their clinical presentation and impact on the decision-making process towards the best treatment approach. The latest evidence on novel treatment methods for acute aortic syndromes is presented, and the diverse dissection classification systems that remain uncertain are discussed, which reveals the need for shared terminology and more clarity. Finally, future aspects are discussed in treating acute aortic dissection, such as the endovascular treatment of aortic dissection Type A and biomarkers for acute aortic syndromes.

Aortic Remodeling After Stepwise External Wrapping for Type A Acute Aortic Dissection

BACKGROUND

The optimal repair technique for type A acute aortic dissection is graft replacement; however, the treatment approach in high-risk patients remains controversial or suboptimal.

METHODS

We have retrospectively analyzed a cohort of high-risk patients who were admitted to our center for type A acute aortic dissection and who were treated by a new surgical approach using artificial grafts (stepwise external wrapping) between January 2016 and January 2020. The primary endpoints included inhospital mortality and survival during follow-up. Secondary endpoints included the assessment of aortic remodeling after ascending aorta wrapping.

RESULTS

Among the 134 patients admitted for type A acute aortic dissection, 43 patients underwent stepwise external wrapping. The mean patient age was 79.1 ± 6.8 years. The new standard European System for Cardiac Operative Risk Evaluation score was 64% ± 12%. There was one hospital death (2.3%). There were two major complications of persistent cerebral disorder (4.6%). Minor complications included temporary neurologic disorder (2.3%) and renal failure (2.3%). The intensive care unit and hospital stays were 2.8 ± 1.0 days and 11.7 ± 2.5 days, respectively. The follow-up survival rate was 95.3% ± 6.2% and 91% ± 10.2% at 1 and 3 years, respectively, after surgery. There was no aortic-related death during follow-up. At 1 year after surgery, complete remodeling of the ascending aorta was obtained in 30 patients (85.7%), and 5 patients (14.3%) showed partial remodeling.

CONCLUSIONS

Our stepwise external wrapping technique was associated with excellent outcomes for high-risk patients with type A acute aortic dissection.

Current management of acute type B dissection in 2021

The rationale for thoracic endovascular aortic repair (TEVAR) for type B aortic dissection depends on the phase of disease: acute phase, which is 'complicated', subacute to early chronic phase, which requires 'preemptive TEVAR' and chronic phase, which entails 'prevention of further dilatation and rupture'. Low operative mortality and morbidity after TEVAR for complicated acute type B aortic dissection have been reported with significant improvement during midterm survival. 'Retrograde' type A dissection, which can be described as type B_0,X (X>3) according to a new reporting standard, has reportedly been treated with TEVAR with less invasiveness. TEVAR is the first and possibly the only effective strategy for acute type B dissection, so that expansion of indications for type B_0,X, as described in the new reporting standard has been validated.

Current Understanding of Aortic Dissection

The aorta is the largest artery in the body, delivering oxygenated blood from the left ventricle to all organs. Dissection of the aorta is a lethal condition caused by a tear in the intimal layer of the aorta, followed by blood loss within the aortic wall and separation of the layers to full dissection. The aorta can be affected by a wide range of causes including acute conditions such as trauma and mechanical damage; and genetic conditions such as arterial hypertension, dyslipidaemia, and connective tissue disorders; all increasing the risk of dissection. Both rapid diagnostic recognition and advanced multidisciplinary treatment are critical in managing aortic dissection patients. The treatment depends on the severity and location of the dissection. Open surgical repair is the gold standard of treatment for dissections located to the proximal part of the aorta and the arch, while endovascular interventions are recommended for most distal or type B aortic dissections. In this review article, we examine the epidemiology, pathophysiology, contemporary diagnoses, and management of aortic dissection.

Duration of deep hypothermic circulatory arrest for aortic arch surgery: is it a myth, fiction, or scientific leap?

INTRODUCTION

The use of deep hypothermic circulatory arrest (DHCA) to provide aortic surgeons with a bloodless operative field while simultaneously protecting the brain and peripheries from ischemic damage revolutionized cardiac and aortic surgery, and is currently used in specialist centers across the globe. However, it is associated with manifold adverse outcomes, including neurocognitive dysfunction and mortality. This review seeks to analyze the relationship between DHCA duration and clinical outcome, and evaluate the controversies and limitations surrounding its use.

EVIDENCE ACQUISITION

We performed a review of available literature with statistical analysis to evaluate the relationship between DHCA duration (<40 min and >40 min) and key clinical outcomes, including mortality, permanent and temporary neurological deficit, renal damage, admission length, and reintervention rate. The controversies surrounding DHCA use and future directions for care are also explored.

EVIDENCE SYNTHESIS

Statistical analysis revealed no significant association (P>0.05) between DHCA duration and clinical outcomes (early and late mortality rates, neurological deficit, admission length, and reintervention rate), both with and without adjunctive perfusion techniques.

CONCLUSIONS

Available literature suggests that the relationships between DHCA duration (with and without adjunctive perfusion) and clinical outcomes are unclear, and at present not statistically significant. Alternative surgical and endovascular techniques have been identified as promising novel approaches not requiring DHCA, as have the use of biomarkers to enable early diagnosis and intervention for aortic pathologies.

Alternative management of proximal aortic dissection: concept and application

Open surgery remains the mainstay of treatment for acute type A aortic dissection and should be offered to most patients. However, there are elderly patients in which surgical treatment may be deemed extremely high risk or futile. Endovascular treatment approaches have been applied to a small number of these patients and data are limited to case reports and small series. The application of endovascular therapies to ascending aorta is currently limited by anatomical and technical challenges posed by the dynamic motion of the ascending aorta and the proximity of vital structures to intended landing zones (aortic valve, coronary arteries, and supra-aortic branches) and lack of specially designed endografts to address these issues. While thoracic endovascular aortic repair (TEVAR) has replaced open aortic repair for a suitable lesion in distal aortic dissection, some selected patients with type A aortic dissection at high surgical may be candidates. Hence, there is potential because, in proximal (Stanford type A) dissections, 10–30% of patients are not accepted for surgery, and 30–50% are technically amenable for TEVAR. Recent experience has shown that carefully selected patients with favorable anatomical characteristics may be subject to endovascular stent-graft treatment as a last resort with mixed results. Technical improvement is necessary to offer. satisfactory endovascular options in non-surgical candidates.

Endovascular repair of the aortic arch: State of the art

BACKGROUND

Open total arch replacement remains the gold standard treatment for aneurysms and dissections involving the aortic arch. However, high-risk surgical candidates may benefit from endovascular techniques to reduce the risk of perioperative mortality and morbidity, especially neurologic complications. Numerous endografts are available for investigational use in the aortic arch as part of investigational device exemption (IDE) programs. Some devices are fenestrated or scalloped, while others are branched, ranging from single branch to triple branch stent-grafts. Furthermore, chimney techniques and in situ fenestration may be utilized in bailout or emergent situations.

RESULTS

Initial results describing outcomes of complete endovascular repair of the aortic arch are encouraging, with current data estimating that technical success ranges from 84.2% to 100%. Moreover, operative mortality may be as high as 13.2%, while neurologic complications also remain common, with stroke rates being as high as 20% and spinal cord ischemia being as high as 3.1%. However, more data are necessary to determine the comparative treatment effect of endovascular stent-grafting of the aortic arch, compared with conventional open and hybrid repairs. Longitudinal follow-up is also lacking, which will determine the long-term durability of endografts in the aortic arch. Nevertheless, endovascular repair represents an important opportunity for improving outcomes in patients with complex and potentially devastating pathologies of the aortic arch.

Back-Table Modified Stent-Graft for Endovascular Repair of Ascending Aorta

OBJECTIVES

To investigate the effectiveness of modified stent-grafts (SGs) for the management of ascending aortic pathologies.

MATERIALS AND METHODS

From January 2015 to December 2019, 31 individuals were treated by ascending aortic endovascular repair with a back-table modified SG for acute (n=4) or chronic (n=1) type A aortic dissections, penetrating aortic ulcers (n=18), pseudoaneurysms (n=2), anastomotic fistula (n=1), and endoleaks after thoracic endovascular aortic repair (TEVAR) (n=5). The commercially available thoracic aortic SGs were modified with a fenestration or truncation technique on the back-table according to aortography during the operation.

RESULTS

The 30-day mortality and aorta-related mortality rates were 12.9% and 6.5%, respectively. There were 2 strokes, 3 respiratory insufficiencies, and 6 endoleaks during hospitalization. During a mean follow-up of 28.8±16.6 months, the overall survival rates at 1 year and 3 years were both 80.6%. Free from adverse event rates at 1 year and 3 years were 88.9% and 84.7%, respectively. There were 2 deaths during follow-up: One patient died of cachexia 1 month after discharge, and the other patient died of acute myocardial infarction 3 months after discharge. One patient with a pseudoaneurysm underwent open ascending aorta replacement 3 months after discharge for a type Ia endoleak. Another patient suffered from cerebellar infarction 17 months after discharge.

CONCLUSION

The modified SG for endovascular repair of the ascending aorta is a practicable alternative and presents acceptable outcomes in high-risk patients.

Endovascular Stent-Graft Repair of the Ascending Aorta: Assessment of a Specific Novel Stent-Graft Design in Phantom, Cadaveric, and Clinical Application

Purpose

To test a stent-graft specifically designed for the ascending aorta in phantom, cadaver, and clinical application, and to measure deployment accuracy to overcome limitations of existing devices.

Methods

A stent-graft has been designed with support wires to fixate the apices toward the inner curvature, thereby eliminating the forward movement of the proximal end which can happen with circumferential tip capture systems. The device was deployed in three aortic phantoms, and in four cadavers, deployment precision was measured. Subsequently, the device was implanted in a patient to exclude a pseudoaneurysm originating from the distal anastomosis after ascending aortic replacement.

Results

The stent-grafts were successfully deployed in all phantoms and cadavers. Deployment accuracy of the proximal end of the stent-graft was within 1 mm proximally and 14 mm distally to the intended landing zone on the inner curvature, and 2–8 mm distal to the intended landing zone on the outer curvature. In clinical application, the pseudoaneurysm could be successfully excluded without complications.

Conclusion

The novel stent-graft design promises accurate placement in the ascending aorta. The differential deployment of the apices at the inner and outer curvatures allows deployment perpendicular to the aortic axis.

Level of Evidence

No level of evidence.

Endovascular treatment of the dissected proximal aortic arch: a systematic review

OBJECTIVES

Surgical repair of aortic dissection involving the proximal aortic arch is associated with higher morbidity and mortality, in particular when elderly high-risk patients are concerned. Endovascular treatments for this disease are under evaluation and some reports exist. We investigated the current use of catheter-based treatments for the dissected proximal aortic arch repair.

METHODS

We searched in PubMed and MEDLINE databases up to the end of June 2020 for studies on endovascular treatment of the dissected proximal aortic arch. Data on demographic, procedure and stent graft (SG) details, access route, mortality with cause of death, complications and follow-up were extracted. A systematic review on the employed technology, procedure and outcome was performed.

RESULTS

A total number of 15 articles (13 retrospective reports and 2 case reports) were deemed eligible and were included in the study. In total, 140 patients (mean age: 56.7 years in 106 cases) received endovascular treatments for the dissected proximal aortic arch (unspecific aortic dissection: 14; acute and subacute type A aortic dissection: 88; chronic type A aortic dissection: 23; type B aortic dissection with retrograde type A dissection: 15). The procedure strategy included unspecific thoracic endovascular aorta repair (TEVAR) (n = 8), TEVAR + supra-aortic debranching (n = 2), TEVAR + cervical bypass (n = 8), TEVAR + periscope SG (n = 12), TEVAR + chimney graft (n = 8), TEVAR + branched SG (n = 21) and TEVAR + fenestration (n = 81). Procedural success rate was 95.6% for 116 reported cases. Complications included endoleaks (postoperative: 2; late: 5), stroke (n = 4), late SG-induced new entry (n = 3) and new false lumen formation (n = 1). Hospital mortality was 5% (6 cases) in 13 reports (120 patients). The mean follow-up time was 26.2 ± 29.4 months and 2 patients died during follow-up.

CONCLUSIONS

As an alternative to surgery for high-risk patients with a dissected proximal aortic arch, the endovascular treatment seems to be promising in highly selected cases. Further studies with long-term results and specifically designed devices are required to standardize this approach.

Anesthetic Considerations in Endovascular Repair of the Ascending Aorta

Since the first endovascular aortic repair in 1990, endovascular devices and the indications for their use have significantly grown. Considerable progress has been made in endovascular devices and techniques, such that endovascular repair is now considered first-line treatment for patients with descending aortic disease. However, for patients with ascending aortic disease, open surgical repair with cardiopulmonary bypass and hypothermic cardiac arrest was the only option until recently. Although the outcomes for open surgical repair of the ascending aorta have improved over the years, approximately 30% of patients with an emergent surgical indication, such as type A aortic dissection, are considered to be too high risk for open repair. For these patients, endovascular repair of the ascending aorta offers a life-saving procedure. The ascending aorta is regarded as the final frontier for endovascular therapy. Endovascular repair of it has posed a formidable challenge thus far, due to its unique anatomy, hemodynamic forces, and lack of an appropriate stent-graft designed specifically for the ascending aorta. Although currently there are no comprehensive data from randomized clinical trials, there are several case series and case reports that have shown favorable outcomes. Improvements in available devices soon will drive an exponential increase in the number of patients undergoing endovascular ascending aortic repair. In this review, the authors discuss multiple aspects of endovascular ascending aortic repair including the unique surgical and anesthetic considerations, the devices used, and the available outcomes data, and future directions are also explored.

Systematic review and meta-analysis of endovascular interventions for Stanford type A aortic dissection

OBJECTIVE

The standard surgical approach to Stanford type A aortic dissection is open repair. However, up to one in four patients will be declined surgery because of prohibitive risk. Patients who are treated nonoperatively have an unacceptably high mortality. Endovascular repair of the ascending aorta is emerging as an alternative treatment for a select group of patients. The reported rates of technical success, mortality, stroke, and reintervention have varied. The objective of the study was to systematically report outcomes for acute type A dissections repaired using an endovascular approach.

METHODS

The systematic review and meta-analysis was conducted in accordance with the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines. We performed online literature database searches through April 2020. The demographic and procedural characteristics of the individual studies were tabulated. Data on technical success, short-term mortality, stroke, and reintervention were extracted and underwent meta-analysis using a random effects model.

RESULTS

Fourteen studies with 80 cases of aortic dissection (55 acute and 25 subacute) were included in the final analysis. A wide variation was found in technique and device design across the studies. The outcomes rates were estimated at 17% (95% confidence interval [CI], 10%-26%) for mortality, 15% (95% CI, 8%-23%) for technical failure, 11% (95% CI, 6%-19%) for stroke and 18% (95% CI, 9%-31%) for reintervention. The mean Downs and Black quality assessment score was 13.9 ± 3.2.

CONCLUSION

The technique for endovascular repair of type A aortic dissection is feasible and reproducible. The results of our meta-analysis demonstrate an acceptable safety profile for inoperable patients who otherwise would have an extremely poor prognosis. Data from clinical trials are required before the technique can be introduced into routine clinical practice.

Endovascular ascending aortic repair in type A dissection: A systematic review

PURPOSE

Up to 10% of acute type A aortic dissection (TAAD) patients are deemed unfit for open surgical repair, exposing these patients to high mortality rates. In recent years, thoracic endovascular aortic repair has proven to be a promising alternative treatment modality in specific cases. This study presents a comprehensive overview of the current state of catheter-based interventions in the setting of primary TAAD.

METHODS

A literature search was conducted, using MEDLINE and PubMed databases according to PRISMA guidelines, updated until January 2020. Articles were selected if they reported on the endovascular repair of DeBakey Type I and II aortic dissections. The exclusion criteria were retrograde type A dissection, hybrid procedures, and combined outcome reporting of mixed aortic pathologies (e.g., pseudoaneurysm and intramural hematoma).

RESULTS

A total of 31 articles, out of which 19 were case reports and 12 case series, describing a total of 92 patients, were included. The median follow-up was 6 months for case reports and the average follow-up was 14 months for case series. Overall technical success was 95.6% and 30-day mortality of 9%. Stroke and early endoleak rates were 6% and 18%, respectively. Reintervention was required in 14 patients (15%).

CONCLUSION

This review not only demonstrates that endovascular repair in the setting of isolated TAAD is feasible with acceptable outcomes at short-term follow-up, but also underlines a lack of mid-late outcomes and reporting consistency. Studies with longer follow-up and careful consideration of patient selection are required before endovascular interventions can be widely introduced.

Catheter-based treatment of the dissected ascending aorta: a systematic review

OBJECTIVES

METHODS

A PubMed search was supplemented by searching through bibliographies and key articles. Demographics, risk score, stent graft detail, access route, mortality, cause of death, complications, reinterventions and follow-up data were extracted and analysed.

RESULTS

Thirty-one articles (7 retrospective reports; 24 case reports/series) were included in the study. In total, 104 patients (mean age 71 ± 14 years) received endovascular treatment for acute (63) or chronic (41) type A dissection. A history of a major cardiac or aortic operation was present in 29 patients. The mean EuroSCORE II was 30 ± 20 in 4 reports. A total of 114 stent grafts were implanted: ‘off-the-shelf’, 65/114; custom made, 12/114; and modified, 7/114. Hospital complications included intraprocedural conversion to open surgery (2/104), stroke (2/104), coronary stenting (2/104), early endoleak (9/104) and repeat aortic endovascular treatment for endoleak (5/104). Hospital mortality was 10% (intraoperative death 2/104). Mean duration of follow-up time was 21 ± 21 months (range 1–81 months); follow-up data were available for 86 patients: 10 patients died of non-aortic-related causes; reintervention for aortic disease (endovascular repair or open surgery) was performed in 8 patients.

CONCLUSIONS

Catheter-based ascending aorta repair for type A aortic dissection with the entry tear in the ascending aorta can be considered in carefully selected high-risk patients. Further analysis and specifically designed devices are required.

Zone 0 Thoracic Endovascular Repair After Aortic Wrapping for Acute Aortic Syndrome

We report a successful treatment of type A acute aortic syndrome (AAS)-associated aortic arch aneurysm in a 71-year-old man with major comorbidities. The ascending aorta was wrapped with artificial graft, and supra-aortic debranching was constructed. Then, Zone 0 thoracic endovascular aneurysm repair (TEVAR) with plug occlusion of the left subclavian artery was successfully performed. The patient was discharged in good physical condition without any complications. To our knowledge, this is the first reported case in the literature of successful Zone 0 TEVAR after ascending aorta wrapping and supra-aortic debranching with type A AAS associated with aortic arch aneurysm.

Impact of center volume on outcomes of surgical repair for type A acute aortic dissections

BACKGROUND

Acute type A aortic dissection is a cardiovascular emergency requiring operative intervention. Despite advancements in operative technique and increased specialization of cardiovascular care, operative mortality, and morbidity after repair of type A aortic dissection remain high. Our aim was to assess national trends in outcomes of type A aortic dissection repair and the impact of institutional thoracic aortic repair volume on clinical outcomes and resource use in the United States.

METHODS

Using the procedural and diagnostic codes of the International Classification of Diseases, Ninth Revision, we identified type A aortic dissection repairs from the 2005 to 2014 database of the National Inpatient Sample. Hospitals were classified into low-, medium- and high-volume tertiles based on annual incidence of thoracic aortic operations. Patient demographics and hospital characteristics, as well as outcomes including mortality, cost, and duration of stay, were evaluated using parametric tests for trends and the volume-outcome relationship. We used a multivariable-adjusted logistic regression model to identify factors associated with mortality.

RESULTS

An estimated 25,231 patients received type A aortic dissection repair with an increasing temporal trend in volume and concomitant decrease in mortality. When stratified by hospital volume, 10,115 (40.1%), 8,194 (32.4%), and 6,920 (27.4%) underwent type A aortic dissection at low-volume, medium-volume, and high-volume, respectively. The unadjusted mortality rate in high-volume was the least (21.5% vs 16.8% vs 11.6% for low-volume, medium-volume, and high-volume, respectively; P < .001). Multivariable analysis revealed older age, lesser household incomes and comorbidities, including congestive heart failure (adjusted odds ratio 1.44; P < .001) and coagulopathy (adjusted odds ratio 1.33; P = .01) as statistically significant predictors of mortality; however, the risk-adjusted duration of stay (adjusted odds ratio 0.88; P = .06) was not different between low-volume and high-volume hospitals. After adjusting for patient and hospital characteristics, type A aortic dissection repair at low-volume hospitals was associated with increased likelihood of mortality compared with high-volume hospitals (adjusted odds ratio 2.10; P < .001). Patients undergoing type A aortic dissection repair at low-volume hospitals had increased odds of all complications including stroke, and respiratory complications compared than those at high-volume hospitals (P = .02, P < .001, and P < .001, respectively).

CONCLUSION

The volume of open surgical repair for type A aortic dissection in the United States has increased over the past decade, while mortality has decreased. Hospital aortic operative volume is strongly associated with outcomes for type A aortic dissection repair. Protocols for expeditious transfer of patients to high volume aortic centers may serve to further decrease the acute mortality and complications of this procedure.

The future of stenting in patients with type A aortic dissection: a systematic review

Acute type A aortic dissection (ATAAD) carries high morbidity and mortality rates and is a clinical emergency. The reported mortality rate is 50% to 65% within the first 48 hours without surgical intervention. Open surgery therefore remains the gold standard management for ATAAD. However, in patients who are deemed unfit for surgery and where possible, endovascular repair offers a useful alternative to medical treatment alone or high-risk open surgical repair. Several case reports, case series, and retrospective studies have reported good outcomes following endovascular treatment. The endovascular option also has comparable early and late outcomes, favourable aortic remodelling, and satisfactory overall survival despite having a higher-risk patient cohort. However, stenting in patients with ATAAD undoubtedly still has several limitations and technical challenges.

Volume-Outcome Relationships in Surgical and Endovascular Repair of Aortic Dissection

BACKGROUND

As surgical mortality decreases and endovascular utilization increases, it is unknown whether volume-outcome relationships exist in thoracic aortic dissection repair. We characterized volume-outcome relationships for surgical and endovascular management of thoracic aortic dissection.

METHODS

Patients aged more than 18 years undergoing repair of thoracic aortic dissection in the United States between 2010 and 2014 were identified in seven all-payer state inpatient administrative databases. Patients were divided into groups based on type of repair: surgical repair of type A dissection (TAAD), surgical repair of type B dissection (TBAD), and endovascular repair (TEVAR). Hierarchical logistic regression models evaluated the association between hospital volume and in-hospital mortality.

RESULTS

Overall in-hospital mortality rate was 13.4% (890 of 6650), highest after TAAD (463 of 2918, 15.9%), followed by TBAD (270 of 1934, 14.0%) and TEVAR (157 of 1798, 8.7%). Volume-outcome relationships for adjusted in-hospital mortality were demonstrated for TAAD and TBAD (P-trend < .001), but not TEVAR (P-trend = .11). Adjusted in-hospital mortality differed most for TAAD (fewer than 3 cases per year: 21%, 95% confidence interval, 18% to 24%; vs 11 or more cases per year: 12%, 95% confidence interval, 8% to 16%; P < .001) and TBAD (fewer than 2 cases per year: 18%, 95% confidence interval, 15% to 22%; vs 11 or more cases per year: 9%, 95% confidence interval, 5% to 12%; P < .001), whereas TEVAR did not differ between quartiles. Adjusted mortality was lower at centers with 26 or more overall annual thoracic dissection repairs, compared with any of the three lower-volume quartiles (P < .001).

CONCLUSIONS

This study demonstrated lower mortality at high-volume hospitals for overall repair of aortic dissection, persisting separately for surgical repair of TAAD and TBAD, but not TEVAR. As endovascular technology advances and practice patterns consequently change, analyses should focus on understanding the balance between procedural volume, mortality, and access to care for thoracic aortic dissection.

Back-table Modified Aortic Endograft Deployed via "Innominate Bounce" Technique for Management of a Zone 0 Ascending Aortic Pseudoaneurysm

Ascending aortic pseudoaneurysms pose a difficult therapeutic dilemma. Surgical repair carries high morbidity and mortality risk and may be challenging in patients with unfavorable anatomy or prior aortic surgery. Endovascular repair is difficult due to short landing zones, need for precise delivery, and the lack of adequately sized commercially available devices. This report describes a case of back-table modification of a thoracic aortic stent graft successfully deployed using an "innominate bounce" technique.

Thoracic Endovascular Aortic Repair for Acute Aortic Dissection

Thoracic endovascular aortic repair (TEVAR) for thoracic aortic disease constitutes a paradigm shift in the treatment strategy of aortic dissection, as well as thoracic aortic aneurysms. Conventionally, most patients with Stanford type B acute aortic dissection are treated using conservative medical treatment during the acute phase. However, in patients with complicated type B aortic dissection who present with life-threatening complications, TEVAR has been introduced as a novel and less-invasive alternative and has shown better early results than those observed with conventional therapy. Recently, TEVAR was reported to be effective in not only promoting thrombosis of the false lumen but also in preventing aortic enlargement observed at long-term follow-up. TEVAR has been established as first-line therapy for complicated type B aortic dissection. In contrast, a considerable number of patients who received acute phase medical treatment required surgical intervention for chronic dissecting aortic aneurysms. With the increasing popularity of TEVAR for the treatment of complicated type B aortic dissection, prophylactic and pre-emptive TEVAR has been considered in patients with uncomplicated type B aortic dissection. However, supportive evidence for this strategy is limited, and reassessment is mandatory because it is continuously evolving. Although acute type A aortic dissection is a life-threatening condition, the results of open surgery continue to improve in the modern surgical era. Open surgical treatment is well established and recognized as a gold standard even in the endovascular era. Presently, the application of TEVAR for ascending aortic dissection has undergone a change, and TEVAR is considered a viable rescue option for patients with type A aortic dissection who are not eligible for open surgical repair. However, TEVAR for the descending aorta is well-established treatment for retrograde type A dissection. Several conceptual and technical issues remain unresolved, and technological advances would lead to the development of innovative disease-specific devices and solutions in the future for endovascular treatment of acute aortic dissection. (This is a translation of Jpn J Vasc Surg 2018; 27: 337–345.)

Morphological features of the thoracic aorta and supra-aortic branches in patients with acute Type A aortic dissection in China

OBJECTIVES

This study aimed to investigate the morphological characteristics of the dissected thoracic aorta and brachiocephalic arteries within the Chinese population.

METHODS

A retrospective analysis of computed tomography scans of 387 patients with acute Type A aortic dissection was carried out. The dimensions of the thoracic aorta at multiple levels and other imaging characteristics were studied.

RESULTS

The patients with a maximum diameter ≥55 mm accounted for less than one-third of the population. Among those without Marfan syndrome (MFS) (n = 349), only 114 (32.8%) patients had a maximal aortic diameter ≥ 55 mm, whereas among those with MFS (n = 38), 20 (78.9%) had a maximal aortic diameter ≥ 45 mm. The predicted maximum aortic diameter is 88.46 - 0.81 × height (cm) + 63.02 × body surface area (m2) + 5.50 × (if diabetes, 1, if not, 0) - 6.63 × (if hypertension, 1, if not, 0). A positive correlation was established between a circular false lumen and the probability that brachiocephalic arteries were involved by dissection. The size ratio of false lumen to true lumen was greater in the circumferential group when compared with the crescent group. The independent predictors for the circumferential false lumen were age, atherosclerosis and smoking.

CONCLUSIONS

Herein, the morphological characteristics of the thoracic aorta among Chinese patients with acute Type A aortic dissection were described. The currently recommended criteria for prophylactic aorta surgery were applied to most patients with MFS but not to those without MFS within the Chinese population. Furthermore, the shape of the false lumen was identified as a putative risk factor that might affect the prognosis of the patients.

Endovascular total arch replacement techniques and early results

During the last 20 years, a clear shift has been observed towards thoracic endovascular aortic repair for different aortic pathologies. However, total endovascular repair of the aortic arch remains technically demanding. Simultaneous perfusion of all supra-aortic arteries without longer cerebral ischemia time, whilst trying to avoid cerebral embolization, labels endovascular aortic arch repair with highest level of technical difficulty and surgical expertise. The aim of this article is to present an overview of the current technical options for endovascular aortic arch repair and their early results. Currently, early results are reported from four endovascular arch replacement techniques: hybrid repair, total endovascular approach, chimney grafts and in-situ fenestration. The early results of these different arch replacement techniques are promising, especially the total arch replacement with custom-made fenestrated or branched stent-grafts. Long-term results are unknown, and larger series results and comparative studies are needed to determine safety and efficacy.

Experimental evaluation of homemade distal stent graft fenestration for thoracic endovascular aortic repair of type A dissection by a transapical approach

OBJECTIVE

The use of off-the-shelf stent grafts for thoracic endovascular aortic repair of type A dissections is limited by variability in both the length of the ascending aorta and the location of the proximal intimal tear. This experimental study aimed to assess the feasibility of using a physician-modified thoracic aortic stent graft to treat acute type A dissection by a transapical cardiac approach.

METHODS

The experiments were performed on six cadaveric human heart, ascending aorta, aortic arch, and descending aorta specimens. Fenestration was fashioned in each standard tubular Valiant thoracic stent graft (Valiant Captivia; Medtronic Vascular, Santa Rosa, Calif) to match the anatomy of each specimen. Stent grafts of sufficient length were selected to cover the entire ascending aorta and aortic arch. Stent graft diameters in proximal sealing zones were oversized by 5% to 10%. The length of the fenestration was the distance between the left subclavian artery and the proximal edge of the origin of the brachiocephalic trunk with an additional 10 mm. The diameter of the scallop was that of the brachiocephalic trunk with an additional 5 mm on all sides. The length of the covered portion of the stent graft was the distance between coronary arteries and the proximal edge of the origin of the brachiocephalic trunk. Two lateral radiopaque markers were positioned to delineate the distal and lateral edge of the scallop. Another 3-cm radiopaque marker was sutured onto the sheath to ensure accurate radiologic positioning of the scallop on the outer curve of the aorta. The left ventricle and the thoracic aorta were connected to a benchtop aortic pulsatile flow model. A 5-mm 30-degree lens was introduced through the left subclavian artery to monitor the procedure. The customized stent graft was deployed by a transapical approach under fluoroscopic control.

RESULTS

Median duration of stent graft modification was 21 minutes (range, 17-40 minutes). All attempts to deploy the homemade proximal scalloped stent graft by a transapical approach were successful. Completion angiography demonstrated patency of the supra-aortic trunks and of the coronary arteries in all cases. Macroscopic evaluation did not identify any deterioration of the customized stent graft.

CONCLUSIONS

The use of physician-modified stent grafts is feasible for thoracic endovascular aortic repair of type A dissection by a transapical approach in this model.

Endovascular treatment of acute Type A aortic dissection-the Endo Bentall approach

Outcome after classical surgical repair of acute Type A aortic dissection has steadily improved over the years and several modifications in cannulation and perfusion added to this achievement. However, subgroups remain where results of classical surgical repair still have room for improvement, particularly patients with severe preoperative malperfusion as well as elderly patients with a limited physiological reserve. So far, only small case series or case reports have been published on the endovascular treatment of dissected ascending aortas. However, a tube alone is not sufficient to fix the entire complex underlying problem in the vast majority of patients with acute Type A aortic dissection. In addition, these published reports are either due to a favorable anatomy or due to very localized disease processes, which are the exception and not the rule. The concept of an endovascular valve-carrying conduit may significantly increase the number of patients suitable for endovascular therapy and it may soon be common practice.

Thoracic endovascular repair for acute type A aortic dissection: operative technique

Acute type A aortic dissection is a potentially lethal condition which requires immediate diagnostic and therapeutic intervention. Open surgical repair remains the standard of care as survival rates continue to improve in the modern surgical era. Unfortunately, up to twenty percent of patients are denied surgical therapy because they are deemed medically unfit to undergo open repair. The application of thoracic endovascular aortic repair (TEVAR) has changed the treatment paradigm for aortic disease involving the descending thoracic aorta and may be a viable rescue option for patients with type A dissection who are not eligible for open surgical repair. New endovascular devices and advanced image-guided procedures are continually evolving. This article summarizes the pathology of aortic dissection and focuses on currently available endovascular solutions for transapical and transfemoral stent graft deployment for acute aortic dissection involving the ascending aorta for selected patients who are ineligible for open surgical repair.

The imaging assessment and specific endograft design for the endovascular repair of ascending aortic dissection

Background

Endovascular option has been proposed for a very limited and selected number of Stanford type A aortic dissection (TAAD) patients. We have performed a computed tomography (CT)-based TAAD study to explore appropriate endograft configurations for the ascending aortic pathology.

Methods

TAAD patients treated with optimal CT scans were retrospectively reviewed, and their entry tears (ETs) were identified using three-dimensional and multiplanar reconstructions in an EndoSize workstation. After generating a centerline of flow, measurements, including numerous morphologic characteristics of anatomy, were evaluated and a selected subset of patients were determined to be suitable for endovascular treatments. Proximal diameter and distal diameter of endograft were selected based on diameters measured at the ET level and at the innominate artery (IA) level, with 10% oversizing with respect to the true lumen, but not exceeding the original aortic diameter. The length of the endograft was determined by the distance from the sinotubular junction to IA.

Results

This study covered 126 TAAD patients with primary ET in ascending aorta, among which, according to the assumed criteria, 48 (38.1%) patients were deemed to be suitable for endovascular treatment. The diameters of ascending aorta from the sinotubular junction to the IA level presented a downward trend, and the proximal diameters differed significantly from distal diameters of the endograft for TAAD (39.9 versus 36.2 mm, P<0.01), implying that the conical endograft might be compatible with the ascending pathology. In the ascending aorta, lengths of the endograft should be 50, 60, 70, 80, and 90 mm in five (10.4%), 22 (45.9%), 13 (27.1%), six (12.5%), and two (4.2%) patients, respectively.

Conclusion

In this selected number of Chinese patients, the suitability of endovascular repair has been demonstrated based on the CT imaging. Shorter, larger, and bare spring-free conical endografts were preferred in the ascending aortic pathology.

Prediction of Intimal Tear Site by Computed Tomography in Acute Aortic Dissection Type A

Background and Objectives

Preoperative identification of intimal tear site in acute type A dissection will help procedural planning. The objective of this study was to determine the key findings of computed tomography (CT)-based prediction for tear site and compare the accuracy between radiologists and surgeons.

Subjects and Methods

Multi-detector CT (MDCT) images from 50 patients who underwent surgical repair of type A aortic dissection were retrospectively reviewed by 4 cardiac surgeons with limited experience or by 3 radiologists specialized in cardiovascular imaging. Surgical findings of intimal tear site were used as references.

Results

In surgical findings, the locations of intimal tear that were identified in 43 patients included aorta (n=25), ascending with arch (n=7), and arch only (n=11). The rest were retrograde dissections from the tear of descending aorta. Key CT findings that were most frequently found were defect in the intimal flap shadow (30.0±4.0 patients/reviewer, accuracy 87.0±11.7%) and differential filling of false lumen by phase and location (9.4±2.9 patients/reviewer, 84.8±10.4%). Surgeons predicted tear site (75.0±7.7% vs. 86.7±1.2%, p=0.055) and specified flap defect (80.5±10.3% vs. 95.7±7.4%, p=0.073) with lower accuracy than radiologists.

Conclusions

With MDCT imaging, well-educated surgeons could be accurate in three fourths of cases. There was room for improvement through experience. Considering the substantial possibility of inaccuracy, critical decisions on CT images should be made through thorough reviewing by as many experienced radiologists and surgeons as possible.

Endovascular Repair of Type A Aortic Dissection: Current Experience and Technical Considerations

Dissection of the ascending aorta, type A aortic dissection (TAAD), represents a surgical emergency with high morbidity and mortality. Current open surgical techniques, although state-of-the-art procedures and having improved outcomes for patients with TAAD over the last decades, confer significant risk of complications and death. Recently, endovascular techniques for repair of both the abdominal and thoracic aorta have gained acceptance within the vascular and cardiovascular surgical communities as a useful tool in select pathologies and patient populations. As development of endovascular technology proceeds ever closer to the aortic valve, thoracic endovascular repair for TAAD deserves special investigation. A comprehensive literature search for studies reporting outcomes of endovascular repair in the ascending aorta was performed. In this review, we compile the worldwide experience of thoracic endovascular repair for TAAD as well as imaging studies for patient selection and the use of hybrid (open plus endovascular) techniques. The authors discuss the remaining challenges that preclude its broader adoption in this role, namely patient selection and device specificity.

Endovascular Repair of Saccular Ascending Aortic Aneurysm After Orthotopic Heart Transplantation Using an Investigational Zenith Ascend Stent-Graft

Purpose: To report the use of an investigational stent-graft to treat an ascending aortic aneurysm in a patient with a heart transplant. Case Report: A 48-year-old man presented with a 3.5×1.5-cm saccular aneurysm in the mid anterior ascending aorta, abutting the sternum. The patient’s history was notable for placement of a left ventricular assist device followed by orthotopic heart transplantation 2 years prior to treat end-stage familial dilated cardiomyopathy. Under compassionate use, a custom-designed ascending aortic stent-graft (Zenith Ascend) was successfully delivered via an 18-F system and deployed just distal to the origin of the left main coronary artery under pulmonary artery catheter–guided rapid ventricular pacing. The patient was discharged the next day, and 6-month follow-up was unremarkable. Imaging at 5 months showed an excluded aneurysm sac with no endoleak or migration. Conclusion: The ideal ascending aortic stent-graft should be low profile, conformable to the arch anatomy, with short tip delivery system and a stepwise deployment mechanism that allows precise placement relative to the ostia of the coronary arteries and the innominate artery. This case illustrates the advancement of endovascular techniques to the most challenging segment of the aorta to decrease morbidity and mortality in high-risk patients.

Computed tomography-based study exploring the feasibility of endovascular treatment of type A aortic dissection in the Chinese population

PURPOSE

To characterize type A aortic dissection (TAAD) in the Chinese population using high-resolution computed tomography (CT) and explore potential candidacy for endovascular repair of TAAD.

METHODS

The imaging studies and medical records of all 302 patients presenting with TAAD at two Chinese hospitals from 2010 to 2013 were reviewed. Of these, 221 patients were excluded because of missing/inadequate preoperative CT scans. The remaining 91 patients (64 men; mean age 51.1±7.5 years) had CT data adequate to assess anatomical suitability for endovascular treatment. Entry tears were identified using multiplanar reconstructions, while morphological measurements were based on a centerline of flow (CLF) technique. Suitability for endovascular treatment was based on a proximal landing zone ≥20 mm long, a true lumen aortic diameter ≤38 mm, and a total aortic diameter ≤46 mm; no coronary bypass grafts originating from the ascending aorta; no malfunctioning aortic valve; and good cerebral and cardiac perfusion.

RESULTS

In the 91 patients, the precise location of the primary proximal entry tear could be identified in only 34 (37.4%) patients; in these patients, the identifiable intimal tears were located 36.4±41.0 mm distal to the closest coronary artery. The CLF was successfully generated in the CT scans of all patients; the mean lumen and total aortic lumen diameters at the entry tear level were 37.6±6.3 and 44.3±13.3 mm, respectively. Based on the CT measurements, stent-graft repair would have been anatomically feasible in 35 (38.5%) patients. No proximal landing zone (n=23), large aortic diameter (n=15), abnormal aortic valve (n=10), previous coronary bypass graft surgery (n=5), and poor cerebral and cardiac perfusion (n=3) were obstacles that affected the suitability for this treatment.

CONCLUSION

Based on high-resolution CT scans, our pilot study suggested that 38% of Chinese patients with TAAD could potentially be treated by stent-grafting based on the anatomical characteristics of the proximal dissection.