Using Machine Learning to Predict Five-Year Reintervention Risk in Type B Aortic Dissection Patients After Thoracic Endovascular Aortic Repair

Purpose: Type B aortic dissection (TBAD) is a high-risk disease, commonly treated with thoracic endovascular aortic repair (TEVAR). However, for the long-term follow-up, it is associated with a high 5-year reintervention rate for patients after TEVAR. There is no accurate definition of prognostic risk factors for TBAD in medical guidelines, and there is no scientific judgment standard for patients’ quality of life or survival outcome in the next five years in clinical practice. A large amount of medical data features makes prognostic analysis difficult. However, machine learning (ML) permits lots of objective data features to be considered for clinical risk stratification and patient management. We aimed to predict the 5-year prognosis in TBAD after TEVAR by Ml, based on baseline, stent characteristics and computed tomography angiography (CTA) imaging data, and provided a certain degree of scientific basis for prognostic risk score and stratification in medical guidelines. Materials and Methods: Dataset we recorded was obtained from 172 TBAD patients undergoing TEVAR. Totally 40 features were recorded, including 14 baseline, 5 stent characteristics and 21 CTA imaging data. Information gain (IG) was used to select features highly associated with adverse outcome. Then, the Gradient Boost classifier was trained using grid search and stratified 5-fold cross-validation, and Its predictive performance was evaluated by the area under the curve (AUC) in the receiver operating characteristic (ROC). Results: Totally 60 patients underwent reintervention during follow-up. Combing 24 features selected by IG, ML model predicted prognosis well in TBAD after TEVAR, with an AUC of 0.816 and a 95% confidence interval of 0.797 to 0.837. Reintervention rate of prediction was slightly higher than the actual (48.2% vs. 34.8%). Conclusion: Machine learning, which combined with baseline, stent characteristics and CTA imaging data for personalized risk computations, effectively predicted reintervention risk in TBAD patients after TEVAR in 5-year follow-up. The model could be used to efficiently assist the clinical management of TBAD patients and prompt high-risk factors.

Clinical Application of an Original Flexible MK Stent-Graft for Nonruptured Thoracic Aortic Aneurysms: Early Experience

Objective

To obtain early MK stent-grafting results for nonruptured thoracic aortic aneurysms and thoracoabdominal aortic aneurysms.

Methods

The authors analyzed 47 patients who underwent treatment using MK stent-grafting. All patients (40 men and 7 women; mean age, 70.8 years) underwent elective procedures. Straight, curved, or tapered MK stents were constructed from a nitinol wire and covered with seamless, cylindrical woven polyester fabric grafts. The mean stent-graft diameter was 24 to 48 mm. In cases where the aneurysm had a short proximal neck (under 15 mm), supraaortic arch artery bypass surgery was planned to lengthen the neck.

Results

Simple stent-grafting without bypass was performed in 26 patients, whereas stent-grafting with supraaortic arch artery bypass was performed in 21 patients. An 18 or 20 F sheath was used as the delivery system in 46 patients (96%). In all 47 patients, the stent-grafts were successfully deployed. Two patients died while in hospital, and another 2 patients suffered a stroke. No other perioperative complications were observed. Postoperative computed tomography after 3 months showed complete thrombus formation in 42 patients (93.3%; 42/45 patients).

Conclusions

Forty-seven patients with thoracic aortic aneurysm were treated with our original flexible MK stent-graft system. Using a small sheath system, straight or curved M-K stent-grafts could be deployed to adequately fit to the aorta as planned. Furthermore, simultaneous bypass surgery widened the application of stent-grafting. However, careful long-term observation is necessary, and further studies are needed to assess such stent-grafting with bypass surgery.

Outcomes of carotid-subclavian bypass performed in the setting of thoracic endovascular aortic repair

BACKGROUND

Subclavian artery revascularization is frequently performed in the setting of thoracic endovascular aortic repair (TEVAR). However, there is little information on the short- and long-term outcomes of patients undergoing carotid to subclavian artery bypass in this clinical setting. As such, this study sought to define the early and late outcomes associated with this procedure.

METHODS

Patients undergoing carotid-subclavian bypass in conjunction with TEVAR between June 2005 and September 2016 were retrospectively identified from a prospectively maintained, single-center aortic surgery database. The 30-day outcomes specific to the carotid-subclavian bypass procedure were analyzed, including cervical plexus nerve injury, bleeding complications, and local vascular complications. All preoperative and postoperative chest radiographs were carefully analyzed to assess for hemidiaphragm elevation indicative of phrenic nerve palsy. Long-term outcomes included primary graft patency and anastomotic complications.

RESULTS

Of 579 consecutive patients undergoing TEVAR during this time interval, 112 patients (19%) underwent concomitant carotid-subclavian bypass. The cohort was 38% female (n = 43), with a mean age of 65 ± 14 years. The majority of conduits were 8-mm polytetrafluoroethylene grafts (n = 107 [95.5%]), with a minority being reversed saphenous vein (n = 4 [3.6%]) or Dacron (n = 1 [0.9%]) grafts. The bypass procedure was done concurrently at the time of TEVAR in 91% (n = 102) of cases. The short-term complication rate attributed specifically to the carotid-subclavian bypass was 29% (n = 33). These complications included phrenic nerve palsy in 25% (n = 27), recurrent laryngeal nerve palsy in 5% (n = 6), axillary nerve palsy in 2% (n = 2), and neck hematoma requiring re-exploration in 1% (n = 1) of patients. The 30-day in-hospital all-cause mortality rate was 5% (n = 6), and the rate of permanent paraparesis or paraplegia was 0.9% (n = 1). Of the operative survivors (n = 106), follow-up imaging of the bypass graft was available in 87% (n = 92) of patients. Actuarial primary graft patency was 97% at 5 years. There were three patients (3%) with bypass graft occlusions, two of which were clinically silent and detected on follow-up imaging. The third was detected because of symptoms of subclavian steal and required repeated revascularization. Two patients (2%) developed a late anastomotic pseudoaneurysm requiring either endovascular (n = 1) or surgical (n = 1) intervention.

CONCLUSIONS

Carotid-subclavian bypass for revascularization of the subclavian artery performed in the setting of TEVAR is durable, although the true complication rate is likely higher than is generally reported in the literature because of a not insignificant rate of phrenic nerve palsy. These data should serve well as "gold standard" comparison data for emerging branch graft devices.

Association of left subclavian artery coverage without revascularization and spinal cord ischemia in patients undergoing thoracic endovascular aortic repair: A Vascular Quality Initiative® analysis

Objectives

Investigate the impact of left subclavian artery coverage without revascularization on spinal cord ischemia development in patients undergoing thoracic endovascular aortic repair.

Methods

The Vascular Quality Initiative thoracic endovascular aortic repair module (April 2011–July 2014) was analyzed. Patients undergoing left subclavian artery coverage were divided into two groups according to revascularization status. The association between left subclavian artery revascularization with the primary outcome of spinal cord ischemia and the secondary outcome of stroke was assessed with multivariable analysis adjusting for between-group baseline differences.

Results

The left subclavian artery was covered in 508 (24.6%) of the 2063 thoracic endovascular aortic repairs performed. Among patients with left subclavian artery coverage, 58.9% underwent revascularization. Spinal cord ischemia incidence was 12.1% in the group without revascularization compared to 8.5% in the group undergoing left subclavian artery revascularization (odds ratio (95%CI): 1.48(0.82–2.68), P = 0.189). Multivariable analysis adjustment identified an independent association between left subclavian artery coverage without revascularization and the incidence of spinal cord ischemia (adjusted odds ratio (95%CI): 2.29(1.03–5.14), P = 0.043). Although the incidence of stroke was also higher for the group with a covered and nonrevascularized left subclavian artery (12.1% versus 8.5%), this difference was not statistically significant after multivariable analysis (adjusted odds ratio (95%CI): 1.55(0.74–3.26), P = 0.244).

Conclusion

For patients undergoing left subclavian artery coverage during thoracic endovascular aortic repair, the addition of a revascularization procedure was associated with a significantly lower incidence of spinal cord ischemia.

Functional Assessment and Evaluation of Outcome After Endovascular Therapy With Coverage of the Left Subclavian Artery in Case of Blunt Thoracic Aortic Injury

BACKGROUND

Patients suffering blunt thoracic aortic injury (BTAI) can be treated by use of thoracic endovascular aortic repair (TEVAR). In this setting, the coverage of the left subclavian artery (LSA) is frequently necessary. Nevertheless, the functionality of the upper left extremity after TEVAR had been rarely analyzed. Thus, this study intends to underline the safety of TEVAR as well as to determine the functionality of the left arm after coverage of the LSA.

METHODS

All patients suffering from BTAI treated by endovascular means in 3 centers (Aachen [Germany], Maastricht [Netherlands], and Innsbruck [Austria]) between 1996 and 2009 were retrospectively analyzed. The safety of the procedure had been assessed by the morbidity and mortality rate. The mid-term functional status of the upper left extremity was evaluated by using the DASH score (disabilities of the arm shoulder and hand).

RESULTS

Forty-six patients (40 male, 6 female), mean age 39.4 ± 16.9 years suffered from BTAI caused by traffic accident (n = 31 [67.39%]), by skiing injury (n = 8 [17.39%]), and by fall (n = 7 [15.21%]). All patients underwent TEVAR, the technical success rate was 100%; 1 carotid-carotid subclavian bypass implantation was necessary. LSA coverage was performed in 76% (35/46) of the cases. Total complication rate was 17.3% (8/46); the endoleak rate was 8.6% (4/46) (2 × Ib, 1 × IIa, 1 × IV). Further complications were bypass and endograft occlusion. The postoperative mortality rate was 6% (3/46), the DASH score was completed in 65% (30/46). The study population reached a mean value of 17 ± 20, which is comparable to a nonharmed reference group (10.10 ± 14.68). A significant correlation between the DASH score and patients age could be demonstrated (2-sided P value: 0.0213).

CONCLUSIONS

Endovascular therapy of BTAI revealed a good primary success rate. An adequate mid-term functional status of the upper left extremity could be assessed in comparison to a nonharmed reference group.

Endografting of the Aortic Arch

In recent years, endovascular repair with stent-grafts has made great advances as a minimally invasive alternative to conventional open surgery in the treatment of aortic aneurysm and dissection. Although many commercial endograft systems are now used worldwide for the treatment of these pathologies in the abdominal aorta, only a few dedicated stent-grafts have been developed for use in the thoracic aorta. However, these second-generation commercial endografts have almost identical specifications and performance profiles in terms of structure, function, and delivery mechanism as stent-graft systems employed in the abdominal aorta. Thus, endografts have been used in the thoracic aorta with little consideration to the morphological and hemodynamic characteristics specific to the aortic arch and the deployment techniques needed to navigate this curved region of the thoracic aorta. This review will survey the literature on aortic arch stent-graft repair and identify key elements critical to the successful design of an endograft to treat lesions in the aortic arch.

Techniques for Preserving Vertebral Artery Perfusion During Thoracic Aortic Stent Grafting Requiring Aortic Arch Landing

Thoracic endografting offers many advantages over open repair. However, delivery of the device can be difficult and may necessitate adjunctive procedures. We describe our techniques for preserving perfusion to the left subclavian artery despite endograft coverage to obtain a proximal seal zone. We reviewed our experience with the Talent thoracic stent graft (Medtronic, Santa Rosa, CA). From 1999 to 2003, 49 patients received this device (29 men, 20 women). Seventeen patients required adjunctive procedures to facilitate proximal graft placement. We performed left subclavian-to-left common carotid artery transposition (6), left common carotid-to-left subclavian artery bypass with ligation proximal to the vertebral artery (7), and left common carotid-to-left subclavian artery bypass with proximal coil embolization (4). Patients who had anatomy unfavorable to transposition or bypass with proximal ligation (large aneurysms or proximal vertebral artery origin) were treated with coil embolization of the proximal left subclavian artery in order to prevent subsequent type II endoleaks. Technical success rate of the carotid subclavian bypass was 100%. Patient follow-up ranged from 3 to 48 months with a mean of 12 months. Six patients had follow-up <6 months owing to recent graft placement. Primary patency was 100%. No neurologic events occurred during the procedure or upon follow-up. One patient had a transient chyle leak that spontaneously resolved in 24 hours. Another patient had a phrenic nerve paresis that resolved after 3 weeks. We believe that it is important to maintain patency of the vertebral artery specifically when a patent right vertebral system and an intact basilar artery is not demonstrated. Furthermore, we describe a novel technique of coil embolization of the proximal left subclavian artery in conjunction with left common carotid-to-left subclavian artery bypass. This circumvents the need for potentially hazardous mediastinal dissection and ligation of the proximal left subclavian artery in cases of large proximal aneurysms or unfavorable vertebral artery anatomy.

Endovascular Aortic Arch Reconstruction with Supra-Aortic Transposition for Symptomatic Contained Rupture and Dissection: Early Experience in 8 High-Risk Patients

Purpose:

To report our initial experience with total and subtotal endovascular aortic arch reconstruction combined with supra-aortic vessel transposition in high-risk patients and to present a new morphological classification of thoracic aortic lesions for patient and procedure selection.

Methods:

Among 80 patients treated with thoracic stent-grafts at our department between 1997 and 2003, 8 patients (6 men; mean age 71 years, range 45–81) unfit for open repair were not candidates for standard endovascular repair due to inadequate proximal landing zones on the aortic arch. Commercially available endografts (Excluder, Zenith, Endofit, Talent) were used to repair the arch after supra-aortic vessel transposition was performed. The endograft was implanted transfemorally or via an iliac Dacron conduit graft with standardized endovascular techniques and deployed during intravenous adenosine-induced asystole. The imaging data from all thoracic endograft patients was analyzed to classify thoracic and thoracoabdominal lesions according to a 4-level anatomical system.

Results:

Deployment success was 100% after staged supra-aortic vessel transposition, but 1 patient died of endograft-related rupture of the proximal aortic arch. There was no neurological complication. Mean follow-up was 16 months (range 1–36). Patency of all endografts and conventional bypasses was 100%, and no migration was observed. One minor type II endoleak was demonstrated.

Conclusions:

Initial results are encouraging for endovascular aortic arch repair in combination with supra-aortic transposition in selected high-risk patients with complex aortic pathologies.

Endoluminal Repair of a Thoracic Arch Aneurysm Using a Scallop-Edged Stent-Graft

Purpose:

To report a new technique of endoluminal thoracic aortic arch aneurysm repair using a scalloped stent-graft.

Case Report:

A 79-year-old man presented with a 7.5-cm thoracic aneurysm involving the inner curve of the aortic arch. Endoluminal repair was performed with a scalloped stent-graft that allowed perfusion of the brachiocephalic (innominate) artery. Preliminary extra-anatomical left common carotid and subclavian artery bypass grafting had been performed to allow coverage of the origins of these vessels.

Conclusions:

The use of fenestrated endoluminal grafts in the aortic arch can be achieved safely and may increase the treatment options for the high-risk patient.

Complications after Endovascular Treatment of Thoracic Aortic Aneurysms

Purpose:

To retrospectively determine the value of stent-graft repair of descending thoracic aortic aneurysms by analyzing the results and complications.

Methods:

From May 1997 to July 2002, 45 patients (33 men; mean age 69 years, range 31–88) received endovascular treatment for thoracic aortic aneurysms. In 11 patients, emergency treatment was necessary for a contained rupture. The medical records of these patients were reviewed to gather data on the procedures, immediate results, complications, mortality, and survival in follow-up.

Results:

In all cases, the stent-grafts were successfully implanted. In 15 (33%) cases, the subclavian artery was covered by the stent-graft without complications. There was no paraparesis/paraplegia; 2 (4.4%) patients suffered a stroke intraoperatively. The in-hospital mortality was 2.2% (n = 1); 3 (6.7%) patients died within 30 days. Primary endoleaks occurred in 8 (17.8%) cases. Procedural success (technical success without endoleak or death) was 80% (93.3% after primary endoleak repair). During follow-up, 2 (4.4%) secondary endoleaks developed. All endoleaks were treated successfully or sealed spontaneously (n = 2). At a mean 24-month follow-up (range 1–62), 84% of patients were alive.

Conclusions:

The endovascular treatment of thoracic aortic aneurysms appears to be safe and effective, with lower morbidity and mortality than in conventional open operations. For these reasons, endovascular treatment should be administered whenever possible.

Development of a Branched Stent-Graft for Endovascular Repair of Aortic Arch Aneurysms

Purpose:

To develop a branched stent-graft for endovascular repair of aortic arch aneurysm.

Methods:

Four different prototypes of a branched aortic stent-graft were inserted into a rubber model of the human aortic arch under fluoroscopic guidance. Each prototype was tested, modified, and tested again through a series of 4 iterations. The first 3 prototypes had multiple short side branches, as docking sites for extensions into the branches of the aortic arch. The last iteration had only 1 short branch for an extension into the distal aorta and 1 long branch for direct perfusion of the innominate artery.

Results:

With every re-design, the prototype aortic stent-graft became shorter, and its insertion site moved to a more proximally located arch artery. Stent-graft insertion, orientation, and extension also became quicker and easier with each change in device design. However, the only system to perform reliably was the last, which was subsequently used to treat a large, symptomatic pseudoaneurysm of the aortic arch in a high-risk patient.

Conclusions:

None of our multibranched systems was simple, safe, or durable enough for insertion into the aortic arch; only an iteration that had a short branch for an extension into the distal aorta and a long branch for direct perfusion of the innominate artery could be deployed without difficulty or delay.

An IVUS-Based Approach to Traumatic Aortic Rupture, with a Look at the Lesion from inside

Purpose:

To review a single-institution experience with endovascular repair of acute traumatic aortic rupture (ATAR) performed on an emergency basis using intravascular ultrasound (IVUS) exclusively as the navigation tool for stent-graft implantation (no arteriography).

Methods:

Between September 1998 and November 2006, 26 consecutive patients (19 men; mean age 38619 years, range 15 to 83) underwent endovascular repair of ATAR performed by a surgical team using IVUS and fluoroscopy for lesion characterization and stent-graft deployment guidance. Transesophageal echocardiography was routinely used in all patients to visualize the aortic lesion and rule out residual flow after device deployment. Sealing of the aortic tear was evaluated by postoperative contrast-enhanced computed tomography.

Results:

IVUS revealed an extensive disruption of the tunica intima and media (>180°) in 46% (12/26) of patients; the disruption was circumferential in 3 cases, with pseudocoarctation. The aortic diameter at the site of rupture measured 24±4 mm. Primary technical success was 92% (24/26); 1 persistent but small proximal endoleak and an intraoperative death (4% in-hospital mortality) from abdominal bleeding in an octogenarian accounted for the failures. Procedure-related complications (2, 8%) included the aforementioned endoleak and a minor stroke secondary to cerebral embolization. There was no paraplegia associated with the repairs. Conclusion: Endovascular repair of acute traumatic aortic disruption yields promising results, with high technical success and minimal procedure-related morbidity. IVUS as the primary navigation tool for device implantation allows prompt endovascular setup, instant aortic measurements, and precise visualization of the aortic disruption.

Technical Strategies to Expand Stent-Graft Applicability in the Aortic Arch and Proximal Descending Thoracic Aorta

The endovascular repair of thoracic aortic pathology is on an evolutionary threshold, as advancing technologies and techniques combine to offer the interventionist expanded treatment opportunities. A variety of maneuvers are recommended to address the landing zone limitations to thoracic endografting imposed by the arch vessels: transostial bare stent placement, intentional occlusion of the arch vessel origin, vessel transposition, and bypass grafting. These adjunctive techniques can help us extend the option of a minimally invasive treatment to a greater number of patients with severe thoracic aortic lesions and comorbidities that place them at high risk for standard surgical intervention.

Stent Grafts for Thoracic Aortic Pathology: Single-Center Experience in Western Australia

The purpose of this article is to report a single-center experience in treating thoracic aortic pathology with stent grafts. This is a retrospective review of cases done within a period of 30 months.

Between January 2002 and May 2004, 12 patients were treated in our institution with thoracic stent grafts ( n = 12) for various clinical conditions. There were seven men and five women. Three patients required emergency treatment ( n = 3), two for aortic transection and one for iatrogenic injury during lung biopsy. Others were treated electively ( n = 9).

All patients were high risk for open surgery. There was one perioperative death, with a patient with multiple trauma succumbing to head injury 4 weeks after stent graft insertion. There was no incidence of paraplegia. Three patients underwent bypass surgery in the neck to achieve an adequate proximal seal zone prior to stent grafting. One patient with an aneurysm of the descending thoracic aorta required an extension limb below the original graft for an increase in sac size, possibly owing to endotension. Renal failure occurred in one patient and resolved without dialysis. One patient died 18 months after her procedure, possibly owing to aneurysm expansion.

Stent grafts are a viable alternative to open surgery for thoracic aortic pathology in high-risk individuals. Visceral and spinal cord ischemia is less prevalent with stent grafts compared with open surgery. The short-term results are promising. Long-term follow-up is awaited. Stent grafts might have greater impact in the thoracic aorta than the abdominal aorta for which they were initially developed.

Thoracic endovascular aortic repair with left subclavian artery coverage without prophylactic revascularisation-early and midterm results

Background

The management of the left subclavian artery when coverage is necessary during thoracic aorta endografting remains a matter of debate.

Materials and methods

A retrospective analysis of a single-centre experience with thoracic endovascular aorta repair (TEVAR) was performed. Between April 2004 and October 2012, 125 cases of TEVAR were performed. The analysis focused on patients who required coverage of the left subclavian artery (LSA). We analysed mortality and morbidity with special attention to the rates of cerebrovascular accidents (CVAs) and spinal cord ischaemia (SCI) in the early and midterm.

Results

Of the 125 patients, 53 (42 %, group A) required an intentional coverage of the LSA to obtain an adequate proximal seal for the endograft; the remaining patients constituted group B. None of the patients in group A had protective LSA revascularisation prior to TEVAR. The primary technical success rate was 79.2 vs. 90.3 % (group A vs. group B, p = 0.08), and the primary clinical success rate was 77.4 vs. 82 % (group A vs. group B, p = 0.53). The 30-day mortality rate was 11.3 vs. 11.1 % (group A vs. group B, p = 0.97). The 30-day morbidity was 7.5 vs. 13.9 % (group A vs. group B, p = 0.4). CVA occurred in 1.9 % of group A patients, compared to 1.4 % of patients from group B (p = 0.82). The SCI incidence rate was 0 vs. 1.4 % (p = 0.39). The mean follow-up of group A was 24.1 months (range 2–64.6 months, SD = 19). Additionally, the 1-year estimated survival was 85.5 %, and the 3-year estimated survival was 78 %. There were no midterm CVAs; one event of SCI occurred in the seventh post-operative month in group A.

Conclusion

Our analysis, although retrospective and based on one institution experience, shows a realistic population of TEVAR patients. We prove that TEVAR with coverage of LSA origin can be accomplished with minimal neurological morbidity in this patient population. The study shows that LSA revascularisation is not mandatory before endograft deployment, especially in emergency settings. We also prove that although zone 2 TEVAR extends the proximal landing zone, it does not prevent type IA endoleaks from appearing. A multicentre randomised control trial with higher number of patients is necessary for proper, robust conclusion to be established.

Coverage of the left subclavian artery without revascularization during thoracic endovascular repair is feasible: a prospective study

BACKGROUND

To effectively isolate thoracic aortic lesions in thoracic endovascular aortic repair (TEVAR), an adequate proximal landing zone length is required. The left subclavian artery (LSCA) and other branches of the aortic arch commonly impose limitations on proximal landing zone length, restricting the use of TEVAR. In this study, we investigated the outcomes of LSCA coverage during TEVAR.

METHODS

Between March 2009 and February 2010, we recruited patients with thoracic dissection, aneurysm or trauma from a single center for TEVAR. We categorized patients into 3 groups: full coverage, partial coverage, or noncoverage of the LSCA. We measured pre- and postoperative blood pressures and evaluated complications during follow-up.

RESULTS

We recruited 111 patients for our study: 55 (50%) and 25 (23%) patients had full and partial LSCA coverage, respectively. The upper left arm blood pressures before and after the operations were significantly different between the full-coverage group and the other groups (P < 0.0001). Follow-up occurred between 6 and 20 months, and the mean follow-up time was 10.4 months. Thirteen patients (24%) in the full-coverage group and 2 patients (8%) in the partial-coverage group suffered from simple vertebrobasilar ischemia (VBI). Eleven of the patients with VBI (20%) in the full-coverage group and 2 (8%) patients with VBI in the partial-coverage group had left subclavian steal syndrome at follow-up. No paraplegia or stroke was observed.

CONCLUSIONS

Intentional coverage of the LSCA to obtain an adequate proximal landing zone for TEVAR can be a treatment option for thoracic aortic lesions, although some patients experienced mil complications.

Routine revascularization is unnecessary in the majority of patients requiring zone II coverage during thoracic endovascular aortic repair: A longitudinal outcomes study using United States Medicare population data

Objective

We aimed to evaluate outcomes of thoracic endovascular aortic repair (TEVAR) with left subclavian artery (LSA) coverage without bypass (TEVAR + SUB) to TEVAR with coverage of the LSA with a bypass at the time of the initial procedure or later at a separate procedure (TEVAR + SUB + BYPASS).

Methods

The Centers for Medicare & Medicaid Services inpatient claims for 2006–2007 were queried using Current Procedural Terminology codes for TEVAR, TEVAR + SUB, TEVAR + SUB + BYPASS or later as a separate procedure.

Results

A total of 2676 patients underwent TEVAR; 869 (32.5%) underwent TEVAR + SUB and 49 (5.6%) TEVAR + SUB + BYPASS. At the time of the initial procedure, TEVAR + SUB + BYPASS was associated with a higher incidence of stroke compared to TEVAR + SUB (12.8% vs. 3.8 %; p = 0.0033). Among TEVAR + SUB, only 1.93% (50 patients) had a subsequent bypass performed during a one-year follow-up. Overall rates of morbidity ( p = 0.004) and mortality ( p = 0.011) trended towards significance in favor of TEVAR + SUB.

Conclusions

TEVAR + SUB were associated with lower rates of mortality and complications. Only a small percentage of TEVAR + SUB required a bypass at one year after procedure. Our data suggest that routine LSA bypass during TEVAR is unnecessary and associated with increase morbidity and mortality.

Neurological complications of thoracic endovascular aortic repair

Thoracic endovascular aortic repair (TEVAR) has decreased the morbidity and mortality associated with open surgical repair of descending thoracic aortic diseases, but important complications unique to the procedure remain. Spinal cord ischemia and infarction is a recognized complication caused by endovascular coverage or injury to spinal cord collateral vessels. Stroke is a consequence of thromboembolism or coverage of aortic arch branch vessels with insufficient collateral circulation. Understanding the risk factors and the pathophysiology of neurological complications of TEVAR are important for the successful anesthetic and surgical management and treatment of patients undergoing endovascular procedures involving the thoracic aorta.

Evaluation of the vertebrobasilar system in thoracic aortic surgery

BACKGROUND

We evaluated the probability of vertebrobasilar system malperfusion due to occlusion of the left subclavian artery as assessed by preoperative magnetic resonance angiography in patients scheduled to undergo thoracic aortic surgery.

METHODS

(Study 1) From January 2000 through March 2009, we studied variations of vertebral arteries in 301 patients scheduled to undergo thoracic aortic surgery. We classified vertebral artery variations into 3 categories according to the findings on preoperative magnetic resonance angiography: connection type, interrupted right vertebral artery, and interrupted left vertebral artery. (Study 2) From February 2007 through January 2010, we evaluated the cerebral complication in 41 patients who had occlusion of the left subclavian artery with a stent graft.

RESULTS

(Study 1) On preoperative magnetic resonance angiography, the vertebral artery was classified as connection type in 247 patients, interrupted right vertebral artery in 34, and interrupted left vertebral artery in 20. (Study 2) We performed subclavian obstruction test, left-right subclavian artery bypass, or left subclavian artery-left common carotid artery bypass to the 3 patients with interrupted right vertebral artery, respectively. Forty patients (98%) out of 41 patients had no complication after occlusion of the left subclavian artery.

CONCLUSIONS

Preoperative magnetic resonance angiography is useful for detection of the patients with high risk of vertebrobasilar system malperfusion due to occlusion of the left subclavian artery.

Delayed endovascular treatment of descending aorta stent graft collapse in a patient treated for post- traumatic aortic rupture: a case report

BACKGROUND

We report a case of delayed endovascular correction of graft collapse occurred after emergent Thoracic Endovascular Aortic Repair (TEVAR) for traumatic aortic isthmus rupture.

CASE PRESENTATION

In 7th post-operative day after emergent TEVAR for traumatic aortic isthmus rupture (Gore TAG® 28-150), a partial collapse of the endoprosthesis at the descending tract occurred, with no signs of visceral ischemia. Considering patient's clinical conditions, the graft collapse wasn't treated at that time. When general conditions allowed reintervention, the patient refused any new treatment, so he was discharged.Four months later the patient complained of severe gluteal and sural claudication, erectile disfunction and abdominal angina; endovascular correction was performed. At 18 months the graft was still patent.

DISCUSSION AND CONCLUSION

Graft collapse after TEVAR is a rare event, which should be detected and treated as soon as possible. Delayed correction of this complication can be lethal due to the risk of visceral ischemia and limbs loss.

How to manage the left subclavian artery during endovascular stenting for thoracic aortic dissection? An assessment of the evidence

BACKGROUND

Despite the publication of recent guidelines for management of the left subclavian artery (LSA) during endovascular stenting procedures of the thoracic aorta, specific management for those presenting with dissection remains unclear. This systematic review attempts to address this issue.

METHODS

Systematic assessment of the published data on thoracic aorta dissection was performed identifying 46 studies, which incorporated 1,275 patients. Primary outcomes included the prevalence of left arm ischemia, stroke, spinal cord ischemia, endoleak, stent migration, and mortality. Outcomes were compared between patients with and without LSA coverage and revascularization incorporating factors such as the number of stents used, length of aorta covered, urgency of intervention, and type of dissection (acute or chronic). Statistical pooling techniques, χ(2) tests, and Fisher's exact testing were used for group comparisons.

RESULTS

As compared with other outcomes, LSA coverage without revascularization in the presence of aortic dissection is much more likely to be complicated by left arm ischemia (prevalence increased from 0.0% to 4.0% [p = 0.021]), stroke (prevalence increased from 1.4% to 9.0% [p = 0.009]), and endoleak (prevalence increased from 4.0% to 29.3% [p = 0.001]). However, revascularization was not shown to reverse these effects. Longer aortic coverage (≥ 150 mm) was associated with an increased prevalence of spinal cord ischemia (from 1.3% to 12.5% [p = 0.011]) and mortality (from 1.3% to 15.6% [p = 0.003]).

CONCLUSION

In patients undergoing endovascular stenting for thoracic aortic dissection, in cases where LSA coverage is necessary, revascularization should be considered before the procedure to avoid complications such as left arm ischemia, stroke, and endoleak, and where feasible, an appropriate preoperative assessment should be carried out.

Treating blunt aortic injuries with endografts: pros and cons of a meta-analysis

Modern management of blunt aortic injury (BAI) is based on evidence from mostly well-conducted meta-analyses as surrogates for prospective randomized controlled trials. There are several obvious pros and cons to this strategy. The advantages rest on the fact that it is unlikely that a prospective randomized trial comparing open surgical repair with endovascular repair will ever be conducted based on ethical grounds and the apparent survival advantage and reduced paraplegia rates associated with an endovascular approach; pooled data from high-volume studies provides for higher statistical power; and a well-conducted meta-analysis provides the ability to control for inter-study variation. The disadvantages of this approach are that meta-analyses are statistical examinations of scientific studies and not scientific studies in and of themselves; sources of bias cannot be controlled by the method of the analysis; and a heavy reliance on published studies can create exaggerated outcomes. Nonetheless, the studies reviewed in this article offer the best glimpse yet at the truth. The evidence grade to support endovascular over open repair for BAI is Level II (intermediate), which suggests that the described effect is plausible but is not quantified precisely or may be vulnerable to bias. The recommendation grade is B (provisional recommendation), which suggests that on balance of the evidence, endovascular repair for BAI is recommended with caution.

Acute traumatic aortic injuries: posttherapy multidetector CT findings

Acute traumatic aortic injury is a life-threatening entity that requires emergent treatment. Treatment was once performed with left thoracotomy, resection of the damaged aortic segment, and placement of an interposition graft. Within the past decade, endovascular therapy has gained increased acceptance, primarily because of a significant decrease in mortality and morbidity compared with those of surgery. The authors reviewed the experience with management of acute traumatic aortic injuries at their institution, as well as that reported in the literature. Complications after endovascular repair include endoleak, endograft collapse, stroke, upper extremity ischemia, paraplegia, graft infection, endograft structural failure, missed injury or stent migration, and access site complications. After surgical repair, paraplegia and ischemia to other organs, graft dehiscence, graft infection, and graft stenosis may occur. With the growing use of endovascular management of acute traumatic aortic injuries and the increased likelihood of patient survival, the radiologist will be expected to be familiar with the findings in these patients and is positioned to play a critical role in early recognition of potential complications. Early diagnosis of the complications of therapy for aortic injury is imperative for reduction of mortality and morbidity.

Endovascular approach to acute aortic trauma

Traumatic thoracic aortic injury remains a major cause of death following motor vehicle accidents. Endovascular approaches have begun to supersede open repair, offering the hope of reduced morbidity and mortality. The available endovascular technology is associated with specific anatomic considerations and complications. This paper will review the current status of endovascular management of traumatic thoracic aortic injuries.

Coverage of the celiac artery during TEVAR: is it ever appropriate?

Adequate seal at the proximal and distal extent of stent grafts in the aorta is paramount to the success of thoracic endovascular aortic repair (TEVAR). Thoracoabdominal aneurysms pose a formidable challenge given their extension into the arch branches proximally and the visceral segment distally. Extension of the landing zone of even 3 to 5 mm can possibly increase the durability of the stent graft and may decrease the chances of future migration or collapse. Although coverage of the subclavian artery to extend the proximal landing zone has been met with initial success, the outcome of coverage of the celiac axis in order to extend the distal landing zone has not been as well studied. Because of the abundance of rich collateral vessels in the foregut, it has been perceived as a potentially safe practice. However, careful angiographic anatomic delineation and patient selection is vital to determine whether concomitant revascularization procedures are warranted.

Occlusion of the left subclavian artery with stent grafts is safer with protective reconstruction

BACKGROUND

Safe fixation of endovascular stent grafts in thoracic aortic disease often requires covering of the left subclavian artery (LSA) with the stent graft. It is controversial whether this occlusion can be done without additional risk of ischemic complications.

METHODS

In 102 patients treated with endovascular stent grafts, the LSA was covered. In a nonrandomized clinical practice, unprotected occlusion of the LSA was performed in 63 patients (61%), whereas 39 patients underwent extrathoracic subclavian to carotid artery revascularization before (n = 28) or concomitantly with (n = 11) the endovascular procedure.

RESULTS

Left cerebral ischemia occurred in 11% of the unprotected group and in 5% of the protected group. The difference was not statistically significant. The difference in spinal cord ischemia was insignificant owing to the low incidence in general, but the covered length of the aorta was significantly longer in the protected group. Arm ischemia after unprotected LSA occlusion occurred in 25%.

CONCLUSIONS

The interpretation of the results remains speculative because many factors contribute to left cerebral ischemia. However, in terms of overall complications, there is a significant difference in favor of the group protected by revascularization of the LSA either before or simultaneously with stent grafting. Arm ischemia is mostly mild and can be managed secondarily. Subclavian revascularization is associated with relatively low risk and should be considered in advance, at least when extended covering of the thoracic aorta is intended.

Standard of practice for the endovascular treatment of thoracic aortic aneurysms and type B dissections

Thoracic endovascular aortic repair (TEVAR) represents a minimally invasive technique alternative to conventional open surgical reconstruction for the treatment of thoracic aortic pathologies. Rapid advances in endovascular technology and procedural breakthroughs have contributed to a dramatic transformation of the entire field of thoracic aortic surgery. TEVAR procedures can be challenging and, at times, extraordinarily difficult. They require seasoned endovascular experience and refined skills. Of all endovascular procedures, meticulous assessment of anatomy and preoperative procedure planning are absolutely paramount to produce optimal outcomes. These guidelines are intended for use in quality-improvement programs that assess the standard of care expected from all physicians who perform TEVAR procedures.