Open repair techniques in the aortic arch are still superior

Update on Existing and Upcoming Branched and Fenestrated Thoracic Aortic Arch Stent Grafts

Conventional management of thoracic aortic arch aneurysm and dissection with aneurysmal degeneration remains open surgical repair. However, multiple branched and fenestrated endograft systems offer promise for hybrid or total endovascular treatment of aortic arch pathology. Two zone 0 solutions involving an aortic arch with innominate branch and ascending aorta components are contemporarily in trial: the Gore thoracic branch endoprosthesis and ascending stent graft in the ARISE II Trial (W. L. Gore & Associates, Newark, Delaware) and the NEXUS Arch Stent Graft System (Endospan Ltd., Herzliya, Israel). Both device systems require a debranching procedure prior to endovascular treatment. Patients deemed appropriate for endovascular treatment with acute pathology or not qualifying for one of these trial devices may undergo homemade single or multiple fenestrated physician-modified endovascular grafts or in situ laser fenestration of aortic arch grafts with branch stenting to treat arch pathology. Ultimately, a durable total endovascular solution must achieve comparable or superior outcomes compared with open surgical repair, at significantly lower impact to patients. Branched and fenestrated endovascular treatments for aortic arch pathology require further investigation and follow-up to determine early, mid, and long-term outcomes including mortality, stroke, and endoleak requiring reintervention.

Structural numerical analysis of a branched modular stent-graft for aneurysms encompassing all zones of the aortic arch

The development of stent-grafts for the total repair of aneurysms in the aortic arch is still a technical challenge due mainly to the anatomical complexity of this region. Research performed here structurally evaluated a modular branched stent-graft for aneurysms encompassing all zones of the aortic arch by means of numerical simulations using fluid-structure interaction. The geometric domain obtained by means of computed tomography was subjected to physiological boundary conditions. The blood was modelled as non-Newtonian by the Carreau model, and the arterial wall was modelled as anisotropic hyperelastic by the Holzapfel model. The material adopted for the stents was Nitinol, and expanded polytetrafluoroethylene (ePTFE) was used for the graft. A comparison of the structural behaviour of the aneurysmal aortic arch before and after stent-graft implantation was performed. The numerical flow model was experimentally verified in vitro on a representative test bench of blood flow in the aortic arch. The stent-graft was shown to minimally modify arterial wall dynamics and was not susceptible to migration and endoleak. Peak stresses and strains were found in the stents and graft, respectively, while the stresses in the aneurysm sac were significantly reduced, of the order of 97.5%, due to the isolation of the arterial wall by the stent-graft.

Frozen Elephant Trunk for Aortic Dissection Using Different Hybrid Grafts: Preliminary Results from a Prospective Study

BACKGROUND

The frozen elephant trunk technique has become popular and led to an expansion of indications for surgery. Various hybrid grafts for the frozen elephant trunk are used, sometimes with significantly different features. The objective of this study was to compare early- and mid-term outcomes after the frozen elephant trunk for aortic dissection using different hybrid grafts.

METHODS

The prospective study included 45 patients with acute/chronic aortic dissections. The patients were randomized into two groups. Group 1 patients (n = 19) were implanted with a hybrid graft E-vita open plus (E-vita OP). Group 2 (n = 26) included patients who received a MedEng graft. The inclusion criteria were type A and type B acute and chronic aortic dissection. The exclusion criteria were as follows: hyperacute aortic dissection (less than 24 h), organ malperfusion, oncology, severe heart failure, stroke, and acute myocardial infarction. The primary endpoint was early- and mid-term mortality. The secondary endpoints were postoperative complications (stroke and spinal cord ischemia, myocardial infarction, respiratory failure, acute renal injury, and re-operation for bleeding).

RESULTS

The rate of stroke and spinal cord ischemia in the E-vita OP vs. MedEng groups was 11% vs. 4% (p = 0.565) and 11% vs. 0% (p = 0.173), respectively. The respiratory failure rate was comparable in both groups (p > 0.999). Acute kidney injury requiring hemodialysis and the need for re-sternotomy in the MedEng group vs. E-vita OP group was 31% vs. 16% (p = 0.309) and 15% vs. none (p = 0.126), respectively. Early mortality in the MedEng and E-vita OP groups did not differ (8% vs. 0, p = 0.501). The mid-term survival in the analyzed groups was 79% vs. 61%, (p = 0.079), respectively.

CONCLUSIONS

No statistically significant differences were observed between patients receiving frozen elephant trunk with the hybrid MedEng and E-vita OP grafts in regard to early mortality and morbidity. Mid-term survival was also non-significant between analyzed groups with a trend toward more favorable mortality in the MedEng group.

Evaluation of Different Cannulation Strategies for Aortic Arch Surgery Using a Cardiovascular Numerical Simulator

Aortic disease has a significant impact on quality of life. The involvement of the aortic arch requires the preservation of blood supply to the brain during surgery. Deep hypothermic circulatory arrest is an established technique for this purpose, although neurological injury remains high. Additional techniques have been used to reduce risk, although controversy still remains. A three-way cannulation approach, including both carotid arteries and the femoral artery or the ascending aorta, has been used successfully for aortic arch replacement and redo procedures. We developed circuits of the circulation to simulate blood flow during this type of cannulation set up. The CARDIOSIM© cardiovascular simulation platform was used to analyse the effect on haemodynamic and energetic parameters and the benefit derived in terms of organ perfusion pressure and flow. Our simulation approach based on lumped-parameter modelling, pressure-volume analysis and modified time-varying elastance provides a theoretical background to a three-way cannulation strategy for aortic arch surgery with correlation to the observed clinical practice.

[Clamshell incision plus full sternotomy as a complex approach to complicated aortic arch aneurysm]

Surgical treatment of aortic arch aneurysm is one of the greatest challenges of aortic surgery. We present a young woman with Marfan syndrome, severe Excavated Pectus and previous Bentall procedure, who underwent emergency surgery for ruptured aortic arch aneurysm. We achieved a successful approach through a Clamshell incision associated with a median re-sternotomy.

Late Retrograde Aortic Dissection after Hybrid Thoracic Endovascular Aortic Repair (TEVAR): A Case Report

Open total arch replacement is allied to high rates of mortality and morbidity; surgeons, therefore, tend to choose hybrid aortic arch repair as a less invasive operative procedure for the treatment of aortic arch aneurysms, especially in high-risk patients. However, studies on the early and late outcomes of patients undergoing hybrid aortic arch repair have revealed high rates of reintervention and reoperation compared with open total arch replacement. Here, we describe a male patient with late retrograde aortic dissection after hybrid thoracic endovascular aortic repair for aortic arch aneurysms. The patient returned 3 years after the procedure with signs of dyspnea on exertion and chest pain. Transthoracic echocardiography and computed tomography showed dissection of the ascending aorta, for which he underwent a redo Bentall procedure. The patient was weaned from cardiopulmonary bypass without any problem and discharged after 7 days.

Parallel grafts and physician modified endografts for endovascular repair of the aortic arch

Aortic arch aneurysms are a challenging clinical problem especially in high-risk patients. Open aortic arch replacement, even in the best of centers, carries significant risk of stroke or death in this high-risk population. Many high-risk patients are deemed inoperable and not offered repair. Branched and fenestrated thoracic endografts are currently undergoing clinical trials in the United States but are not yet commercially available. Many elderly and frail patients have significant brachiocephalic occlusive disease or anatomy excluding them for consideration for such clinical trials. These patients also present with acute aortic syndromes requiring urgent or emergent repair and are unable to participate in clinical trials due to the time required to have such devices available. Alternative endovascular therapies, including parallel stent grafts (including Chimneys, Snorkels and Periscopes) and physician modified thoracic endografts, have been used to treat such high-risk patients combined with commercially available thoracic endovascular aneurysm repair (TEVAR) devices. This paper aims to review the techniques and current reported outcomes from parallel stent grafts and physician modified devices used to treat high risk patients undergoing repair for aortic arch pathologies.

Alternative Approach for Cerebral Protection during Complex Aortic Arch and Redo Surgery

Total arch replacement remains a very demanding surgical procedure. It can be associated with reasonable long-term outcomes but carries serious perioperative complications. Aortic arch surgery has progressed in recent years to a wider adoption of reproducible and reliable techniques. Conventional open, surgical aortic arch replacement is currently offered to the majority of patients, although hybrid and wholly endovascular techniques are gaining popularity. With regards to open arch replacement, the nuances of surgical technique, the mode of cannulation and the optimal cerebral protection protocols remain a matter of debate. We propose an alternative cannulation approach facilitated by the cooperation between cardiac and vascular surgeons. A three-way arterial cannulation including both carotid arteries and the femoral artery (or ascending aorta) is the key feature of this approach. A case series of complex patients is presented to show both the feasibility and relative safety of a standardised new approach with a 100% technical success rate and a 16% 30-day mortality. The three-way cannulation approach may have a role to play for complex and extensive procedures requiring prolonged cerebral protection. We believe that a shared skill set from cardiac and vascular specialists is essential for the safe management and successful outcomes using this adaptive technique.

Hybrid repair versus conventional open repair for thoracic aortic arch aneurysms

BACKGROUND

Thoracic aortic arch aneurysms (TAAs) can be a life-threatening condition due to the potential risk of rupture. Treatment is recommended when the risk of rupture is greater than the risk of surgical complications. Depending on the cause, size and growth rate of the TAA, treatment may vary from close observation to emergency surgery. Aneurysms of the thoracic aorta can be managed by a number of surgical techniques. Open surgical repair (OSR) of aneurysms involves either partial or total replacement of the aorta, which is dependent on the extent of the diseased segment of the aorta. During OSR, the aneurysm is replaced with a synthetic graft. Hybrid repair (HR) involves a combination of open surgery with endovascular aortic stent graft placement. Hybrid repair requires varying degrees of invasiveness, depending on the number of supra-aortic branches that require debranching. The hybrid technique that combines supra-aortic vascular debranching with stent grafting of the aortic arch has been introduced as a therapeutic alternative. However, the short- and long-term outcomes of HR remain unclear, due to technical difficulties and complications as a result of the angulation of the aortic arch as well as handling of the arch during surgery.

OBJECTIVES

To assess the effectiveness and safety of HR versus conventional OSR for the treatment of TAAs.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and AMED databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 22 March 2021. We also searched references of relevant articles retrieved from the electronic search for additional citations.

SELECTION CRITERIA

We considered for inclusion in the review all published and unpublished randomised controlled trials (RCTs) and controlled clinical trials (CCTs) comparing HR to OSR for TAAs.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened all titles and abstracts obtained from the literature search to identify those that met the inclusion criteria. We retrieved the full text of studies deemed as potentially relevant by at least one review author. The same review authors screened the full-text articles independently for inclusion or exclusion.

MAIN RESULTS

No RCTs or CCTs met the inclusion criteria for this review.

AUTHORS' CONCLUSIONS

Due to the lack of RCTs or CCTs, we were unable to determine the safety and effectiveness of HR compared to OSR in people with TAAs, and we are unable to provide high-certainty evidence on the optimal surgical intervention for this cohort of patients. High-quality RCTs or CCTs are necessary, addressing the objective of this review.

Zone 1 Aortic Arch Hybrid Endovascular Repair with Extra-anatomical Bypass: A Meta-analysis

BACKGROUND

The aim of this meta-analysis is to determine the morbidity and mortality outcomes of adult patients with aortic arch disease managed with extra-anatomical bypass avoiding median sternotomy and cardiopulmonary bypass, with simultaneous or staged hybrid zone 1 endovascular aortic repair.

METHODS

Systematic literature searches of the MEDLINE, EMBASE, and Cochrane databases were carried out to identify relevant studies on zone 1 hybrid arch repair. Extracted data were analyzed by random effects models. Primary outcomes included 30-day or in-hospital mortality. Longitudinal survival was analyzed up to 7 years from date of operation. Secondary outcomes included in-hospital morbidity, as well as late endoleak and reintervention.

RESULTS

Twenty studies incorporating 348 patients were included. In-hospital or 30-day mortality was 10.1% (95% confidence interval, 6.7-14.9%). Overall operative technical success was 89.8% (83.7-93.8%). Early type 1 endoleak rate was 14.0% (7.4-24.7%). Stroke prevalence was 9.5% (6.1-14.3%). Spinal cord paraplegia prevalence was 3.8% (1.9-7.6%). Retrograde aortic dissection prevalence was 4.1% (1.5-10.6%). Survival at 1 year postoperatively was 77.2% (66.1-85.4%). Survival at 3 years postoperatively was 73.7% (59.2-84.4%). Survival beyond 4 years postoperatively (range 58-80 months) was 65.9% (53.6-76.4%). Late type 1 endoleak prevalence was 11.8% (5.5-23.7%). Overall rate of reintervention was 11.6% (6.4-20.1%).

CONCLUSIONS

Zone 1 hybrid repair has evidence for satisfactory short- and long-term morbidity/mortality outcomes and may be considered as an alternative approach to aortic arch disease.

Single-center experience with the frozen elephant trunk procedure in 111 patients with complex aortic disease

Background

The frozen elephant trunk (FET) technique is increasingly used for the treatment of acute and chronic aortic arch disease. This study reports our single center experience with the FET technique in patients with complex aortic disease.

Methods

Between 2009 and 2019, 111 consecutive patients underwent aortic arch surgery in our institution using the FET technique for acute type A dissection (AAD group; n=75) or non-acute type A dissection (non-AAD group; n=36; 10 patients with chronic type A dissection; 26 patients with aneurysm), respectively. Relevant perioperative data, including 30-day mortality and neurological complications, were retrospectively obtained from our electronic patient’s records, including follow-up (FU) data of outpatient clinical visits and computed tomography (CT).

Results

Thirty-day mortality in the entire FET cohort was 16.2% (AAD 18.7% vs. non-AAD 11.1%; n=0.414). Severe brain injury was the leading cause of death in AAD patients (12.0% vs. 0% non-AAD; P=0.030). Overall permanent stroke and spinal cord injury was 12.6% and 3.6%. Four patients in the AAD group developed paraplegia and permanent stroke rate was significantly higher in AAD compared to non-AAD patients (17.3% vs. 2.8%; P=0.034). One, 3- and 5-year survival rates were 78.7%±4.0%, 72.2%±4.8%, and 64.3%±6.8% for the total cohort; survival at 1-, 3- and 5-year was 76.7%±5.0%, 71.0%±6.1%, and 64.5%±8.3% for the AAD cohort compared to 83.1%±6.3%, 75.0%±7.9% and 66.7% for non-AAD patients (P=0.579), respectively.

Conclusions

Our single-center experience confirms good early and mid-term survival after the FET procedure in patients presenting with AAD, CAD and aneurysm. Future efforts should focus on reduction of severe neurological complication.

Off-Label Treatment With Transfemoral Bare Stents for Isolated Aortic Arch Dissection

BACKGROUND

Aortic arch dissection is a catastrophic acute event involving the aorta. Its accurate diagnosis and treatment are mandatory to optimize patient outcome. We aimed to assess the efficacy and safety of endovascular treatment with transfemoral bare stents of isolated aortic arch dissection as a valid alternative in patients unsuitable for conventional surgery.

METHODS

In this case series, we report our experience with 3 patients affected by isolated aortic arch dissection treated with endovascular surgery from February 2019 to May 2019. All patients were associated with severe comorbidities emergently referred at our center. Vascular access was achieved by surgical exposure of the right common femoral artery performed under general anesthesia. All patients were observed for at least 3 months.

RESULTS

All patients were treated in a hybrid operative room with transfemoral implantation of a bare metal Jotec E-XL stent released in the aortic arch. The postoperative period was uneventful, and all 3 patients were discharged or transferred on the fourth postoperative day. At follow-up, computed tomography scans showed good results in all patients.

CONCLUSIONS

A purely endovascular approach to located aortic arch dissections, with bare stents, remains challenging, although it has been proven to be a valid alternative treatment in some off-label cases.

Performing Antegrade Selective Cerebral Perfusion Using the AV Cannula: A Novel Approach

Antegrade selective cerebral perfusion has become the preferred choice for brain protection during aortic arch surgery. To perform antegrade selective cerebral perfusion, cannulas have been introduced directly into the ostia of the supra-aortic vessels (SAV) after institution of hypothermic circulatory arrest and opening the aortic arch. We describe a different surgical technique with a new type of cannula for antegrade selective cerebral perfusion. This cannula, called AV (Andrea Venturini) cannula, has been designed to be introduced in the SAV directly using a standard guidewire technique (Seldinger's technique). The AV cannula can also be introduced from the ostia of the SAV if preferred. The AV cannula can be introduced before the institution of hypothermic circulatory arrest and before opening the aortic arch. One great advantage of this technique is that the ostia of the SAV remain free from a cannula, allowing the operator easier access and a faster anastomosis or reimplantation.

Aortic arch aneurysms and dissection-open repair is the gold standard

The aortic arch repair is one of the most complex surgeries and carries a high risk of complications as well as mortality. Since 1975, when the arch repair was first done by Randall B. Griepp using hypothermic circulatory arrest, many new technologies were introduced. But even with the use of antegrade and retrograde perfusion techniques and improvement of surgical techniques and grafts, the rate of mortality, cerebral, spinal, and visceral damage was much higher as compared to any other cardiac surgeries. With further developments aimed at less invasive approaches, thoracic endovascular aortic repair (TEVAR) along with de-branching of supra-aortic vessels or the frozen elephant trunk was introduced. Here, in this article, we review the myriad of approaches to the aortic arch and have come to a conclusion that while traditional open surgery is considered as the gold standard for treatment of extensive aortic arch pathologies, one school of thought suggests hybrid techniques such as the frozen elephant trunk and aortic arch vessel de-branching as more appropriate procedures for high-risk patients, where co-morbidities may contraindicate cardiopulmonary bypass and longer operative times required for traditional repair. No randomized trials are present to compare between open and hybrid or endovascular procedure in normal or high-risk patients. The meta-analysis of most of the studies defines open surgery as the gold standard for arch pathology because the hybrid procedures did not provide any proven survival benefits or decrease in stroke rate and spinal ischemia when compared to open surgery in early, mid, or long-term results.