Retrograde type A aortic dissection after endovascular stent graft placement for treatment of type B dissection

Endovascular therapy in Marfan syndrome: PRO

Marfan syndrome (MFS) is an inherited connective tissue disorder that is associated with arterial fragility and aortic pathologies. The endovascular treatment of patients with MFS is controversial. Published series suggest that while endovascular intervention can be carried out with a low rate of immediate morbidity and mortality, midterm follow up demonstrates sizeable numbers of complications. However, in certain situations-such as rupture, reintervention for patch aneurysms, and elective interventions in which the landing zone is within a previously placed graft-endovascular interventions are appropriate. We present a review of the literature and our institutional perspective on this complex topic.

Endovascular surgery in Marfan syndrome: CON

The frequency of endovascular stent grafting procedures to treat various conditions of the thoracic aorta has increased dramatically over the past three decades. Stent grafting has been applied on a limited basis in patients with Marfan syndrome and other connective tissue disorders, despite recommendations from current guidelines and expert consensus statements against its use in this setting. A review of publications reporting outcomes after stent grafting of the descending thoracic aorta in Marfan patients with acute or chronic aortic dissection indicates that these procedures can be accomplished with rates of early mortality, stroke and spinal cord ischemic injury that are comparable to those observed in patients who do not have Marfan syndrome. However, the rates of primary treatment failure (principally endoleak), secondary treatment failure, need for open repair and late death among the Marfan patients are substantially higher than those observed in patients without this condition. In addition, the rates of retrograde aortic dissection and development of stent-graft induced new entry (SINE), are also greater among patients with Marfan syndrome. All of these findings argue strongly against the routine use of endovascular grafts in Marfan patients with type B or residual type A dissection. Few data are available to assess the role of endografting in Marfan patients with aneurysmal disease, but the progressive aortic dilatation noted in these patients argues strongly against its use in this setting as well. At present, the available data indicate that there is no justification for elective stent grafting in Marfan patients with aortic dissection or aneurysm. The only reasonable indications for primary aortic stent grafting are in the setting of acute aortic dissection or rupture, where the intervention is considered life-saving and rarely, considering the relatively young age of these patients, where the risk of open operation is considered to be prohibitive.

Incidence and risk factors for retrograde type A dissection and stent graft-induced new entry after thoracic endovascular aortic repair

OBJECTIVE

Stent graft (SG)-induced new entry (SINE) and retrograde type A dissection (RTAD) are serious device-related complications occurring after thoracic endovascular aortic repair (TEVAR) for Stanford type B aortic dissection (TBAD) and may lead to endograft-related complications including retrograde dissection and death. The purpose of this study was to investigate the incidence and risk factors for the development of RTAD and SINE after TEVAR for TBAD and to identify the complications associated with this.

METHODS

From April 2005 to October 2013, there were 997 patients who underwent TEVAR for TBAD; 852 were followed up (0-6 years; mean, 2.6 years), and 59 SINEs developed in 53 patients. The oversizing ratio and incidence of RTAD and SINE were compared between proximal bare stent (PBS) and non-PBS groups and RTAD and SINE and non-RTAD and non-SINE groups. The baseline characteristics and SG configurational factors potentially affecting both RTAD and distal SINE were analyzed.

RESULTS

There was no significant difference between PBS and non-PBS groups in the incidence of RTAD. A greater oversizing ratio was related to a higher distal SINE rate. SINE was seen more frequently in smokers and in patients with hypertension, Marfan syndrome, and TEVAR in the chronic phase and less frequently in complicated dissection cases. Device-related factors for SINE were SG with a connecting bar and SG length <165 mm. The SG length <165 mm increased the overall proximal and distal SINE incidence in multivariate analysis.

CONCLUSIONS

The presence of a PBS is not associated with a higher RTAD rate, whereas the use of an SG with a connecting bar and length <165 mm increases the risk of RTAD and SINE after TEVAR.

Retrograde Type A Aortic Dissection After Thoracic Endovascular Aortic Repair: A Systematic Review and Meta-Analysis

Background

Retrograde type A aortic dissection (RTAD) is a potentially lethal complication after thoracic endovascular aortic repair (TEVAR). However, data are limited regarding the development of RTAD post‐TEVAR. This systematic review aims to define the incidence, mortality, and potential risk factors of RTAD post‐TEVAR.

Methods and Results

Multiple electronic searches were performed. Fifty publications with a total of 8969 patients were analyzed. Pooled estimates for incidence and mortality of RTAD were 2.5% (95% confidence interval [CI], 2.0–3.1) and 37.1% (95% CI, 23.7–51.6), respectively. Metaregression analysis evidenced that RTAD rate was associated with hypertension (P=0.043), history of vascular surgery (P=0.042), and American Surgical Association (P=0.044). The relative risk of RTAD was 1.81 (95% CI, 1.04–3.14) for acute dissection (relative to chronic dissection) and 5.33 (95% CI, 2.70–10.51) for aortic dissection (relative to a degenerative aneurysm). Incidence of RTAD was significantly different in patients with proximal bare stent and nonbare stent endografts (relative risk [RR]=2.06; 95% CI, 1.22–3.50). RTAD occurrence rate in zone 0 was higher than other landing zones.

Conclusions

The pooled RTAD rate after TEVAR was calculated at 2.5% with a high mortality rate (37.1%). Incidence of RTAD is significantly more frequent in patients treated for dissection than those with an aneurysm (especially for acute dissection), and when the proximal bare stent was used. Rate of RTAD after TEVAR varied significantly according to the proximal Ishimaru landing zone. The more‐experienced centers tend to have lower RTAD incidences.

How should we manage type B aortic dissections?

Dissection of the descending aorta is a serious and potentially lethal event. Treatment options consist of medical therapy, open surgical replacement of the affected aorta and thoracic endovascular repair. In acute cases, medical treatment is started initially. When complicated, endovascular repair is generally considered as first choice treatment, except for connective tissue disorders where open surgery remains the standard. In stable, uncomplicated patients with risk factors for future aortic growth pre-emptive endovascular repair should be considered in the sub-acute phase of the dissection. The treatment strategy in chronic dissections is somewhat debated. Long-term results and aortic remodeling of endovascular repair are disappointing and open surgery remains the standard.

Restrictive bare stent prevents distal stent graft-induced new entry in endovascular repair of type B aortic dissection

OBJECTIVE

Distal stent graft-induced new entry (SINE) can occur after thoracic endovascular aortic repair (TEVAR) of type B aortic dissection. This study investigated the mechanism of distal SINE and its prevention using a restrictive bare stent (RBS) technique.

METHODS

From January 2013 to December 2014, 68 consecutive type B aortic dissection patients received endovascular repair at our center. The RBS technique was used with distal oversizing (between the diameter of the thoracic stent graft and the descending aorta true lumen diameter at the level of the intended distal edge of the thoracic stent graft) >20%.

RESULTS

Twenty-three patients received TEVAR with a single thoracic stent graft (TEVAR group, n = 23); the rest received TEVAR combined with the RBS technique (TEVAR + RBS group, n = 45). Four distal SINEs occurred in the TEVAR group. Distal oversizing (69.7% ± 35.5% vs 31.2% ± 24.5%; P = .005) and expansion mismatch ratio (132.2% ± 16.9% vs 106.5% ± 11.6%; P < .05) were significantly higher in the SINE patients. Compared with standard TEVAR, TEVAR + RBS was associated with significantly lower distal oversizing (TEVAR vs TEVAR + RBS group, 59.8% ± 24.7% vs 16.7% ± 7.6%; P < .05), lower expansion mismatch ratio (113.8% ± 14.6% vs 103.8% ± 11.7%; P = .012), and lower distal SINE rate (4/23 [17.4%] vs 0/45 [0%]; P = .011). Compared with the TEVAR group, the false lumen was reduced significantly at the level of the RBS distal edge (P = .029).

CONCLUSIONS

Excessive distal oversizing and distal expansion mismatch ratio may contribute to the occurrence of distal SINE. The RBS technique reduced the incidence of distal SINE. Based on our midterm and long-term observations, implantation of an RBS may improve aortic remodeling.

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

Objective

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

Methods

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

Results

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

Conclusion

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

Chimney Technique in Supra-Aortic Branch Reconstruction in China: A Systematic and Critical Review of Chinese Published Experience

BACKGROUND

The chimney graft (CG) technique has been proposed as a complete endovascular supra-aortic branch reconstruction for aortic pathologies. Due to the rapid growth of thoracic endovascular aortic repair (TEVAR) in China, we aimed to investigate the current data of the CG technique in this most populous country.

METHODS

Studies of supra-aortic branch reconstruction using the CG technique from Chinese centers were collected and analyzed.

RESULTS

A total of 294 patients from Chinese centers who underwent TEVAR with CGs were included. There were 301 CGs performed, with a technical successful rate of 97.7%. The rate of early type I endoleaks was 7.1%, and the patency rate of the CGs was desirable. Balloon-expandable bare CGs were significantly associated with good early outcomes and a low rate of endoleaks.

CONCLUSION

Current data from China revealed positive outcomes using CGs for supra-aortic branch reconstruction. Balloon-expandable bare CGs may be the first choice according to the data available but should be considered with caution.

Type B Aortic Dissections: Current Guidelines for Treatment

Stanford type B aortic dissections (TBADs) involve the descending aorta and can present with complications, including malperfusion syndrome or aortic rupture, which are associated with significant morbidity and mortality if left untreated. Clinical diagnosis is straightforward, typically confirmed using CT angiography. Treatment begins with immediate anti-impulse medical therapy. Acute TBAD with complications should be repaired with emergent thoracic endovascular aortic repair (TEVAR). Uncomplicated TBAD with high-risk features should undergo TEVAR in the subacute phase. Open surgical repair is seldom required and reserved only for select cases. It is critical to follow these patients clinically and radiographically in the outpatient setting.

Precise treatment of aortic aneurysm by three-dimensional printing and simulation before endovascular intervention

In this study, three-dimensional printing (3Dp) models and simulation surgeries (SSs) were applied in two challenging aortic cases. The first was an abdominal aortic aneurysm with a complex neck, and the second was a thoracic aortic dissection aneurysm (TADA) with an angled arch. In order to avoid unpredictable obstacles and difficulties, we made optimal surgical plans by using 3D models and virtual simulations. Based on preoperative evaluation system, the surgical plans seemed more reasonable and time-saving.

Impact of thoracic endovascular aortic repair on radial strain in an ex vivo porcine model

Objectives

To quantify the impact of thoracic endovascular aortic repair (TEVAR) on radial aortic strain with the aim of elucidating stent-graft-induced stiffening and complications.

Methods

Twenty fresh thoracic porcine aortas were connected to a mock circulatory loop driven by a centrifugal flow pump. A high-definition camera captured diameters at five different pressure levels (100, 120, 140, 160, and 180 mmHg), before and after TEVAR. Three oversizing groups were created: 0-9% ( n  = 7), 10-19% ( n  = 6), and 20-29% ( n  = 6). Radial strain (or deformation) derived from diameter amplitude divided by baseline diameter at 100 mmHg. Uniaxial tensile testing evaluated Young's moduli of the specimens.

Results

Radial strain was reduced after TEVAR within the stented segment by 49.4 ± 24.0% ( P  < 0.001). As result, a strain mismatch was observed between the stented segment and the proximal non-stented segment (7.0 ± 2.5% vs 11.8 ± 3.9%, P  < 0.001), whereas the distal non-stented segment was unaffected ( P  = 0.99). Stent-graft oversizing did not significantly affect the amount of strain reduction ( P  = 0.30). Tensile testing showed that the thoracic aortas tended to be more elastic proximally than distally ( P  = 0.11).

Conclusions

TEVAR stiffened the thoracic aorta by 2-fold. Such segmental stiffening may diminish the Windkessel function considerably and might be associated with TEVAR-related complications, including stent-graft-induced dissection and aneurysmal dilatation. These data may have implications for future stent-graft design, in particular for TEVAR of the highly compliant proximal thoracic aorta.

Impact of Thoracic Endovascular Repair on Pulsatile Aortic Strain in Acute Type B Aortic Dissection: Preliminary Results

BACKGROUND

The impact of thoracic endovascular aortic repair (TEVAR) on pulsatile aortic strain remains undetermined in patients with Type B aortic dissection (TBAD). Therefore, we quantified pulsatile aortic strain in TBAD patients and control subjects.

METHODS

We retrospectively analyzed two TBAD patients from our database with cardiac-gated computed tomography angiography imaging available before and after TEVAR and two control subjects (67- and 76-year-old males). Patient 1 (54-year-old female) presented with acute TBAD, and Patient 2 (55-year-old male) had Marfan syndrome and ruptured acute TBAD. Custom-developed software was used to compute aortic length, diameter, and area during the cardiac cycle. Pulsatile strain was calculated as systolic increments of length and circumference divided by corresponding diastolic values.

RESULTS

Before TEVAR, pulsatile longitudinal strain of the thoracic aorta was lower in TBAD patients (1.4-1.7%) than in control subjects (2.1-4.5%). After TEVAR, pulsatile longitudinal strain increased proximal to the stent-graft by 65% in the arch of Patient 1 and by 70% in the ascending aorta of Patient 2. Pulsatile circumferential strain was elevated in false lumen patency (4.4-6.2%) compared with thrombosed false lumen (1.4-2.1%) or control subjects (0.9-3.3%). Following TEVAR, circumferential measurements within stented segments were deemed unreliable due to artifacts.

CONCLUSIONS

TEVAR led to a considerable increase of pulsatile longitudinal strain proximal to the stent-grafts, and TBAD was associated with longitudinally stiffer aortas, which may be part of the pathophysiology of TEVAR-related complications such as retrograde dissection and aneurysmal dilatation. These preliminary data call for larger prospective studies.

Acute retrograde type A aortic dissection: morphologic analysis and clinical implications

Background:

This study compares the morphology and outcomes of acute retrograde type A dissections (RTADs) with acute antegrade type A dissections (ATADs), and acute type B dissections.

Materials and methods:

From 2000 to 2016, there were 12 acute RTADs, 96 ATADs, and 92 type B dissections with available imaging. Dissections were characterized using computerized tomography angiography images. We examined clinical features, tear characteristics, and various morphologic measurements.

Results:

Compared with acute type B dissections, RTAD primary tears were more common in the distal arch (75% versus 43%, P = 0.04), and the false-to-true lumen contrast intensity ratio at the mid-descending thoracic aorta was lower (0.46 versus 0.71, P = 0.020). RTAD had less false lumen decompression because there were fewer aortic branch vessels distal to the subclavian that were perfused through the false lumen (0.40 versus 2.19, P < 0.001). Compared with ATAD, RTAD had less root involvement where root true-to-total lumen area ratio was higher (0.88 versus 0.76, P = 0.081). Furthermore, RTAD had a lower false-to-true lumen contrast intensity ratio at the root (0.25 versus 0.57, P < 0.05), ascending aorta (0.25 versus 0.72, P < 0.001), and proximal arch (0.39 versus 0.67, P < 0.05). RTAD were more likely to undergo aortic valve resuspension (100% versus 74%, P = 0.044).

Conclusions:

RTAD tends to occur when primary tears occur in close proximity to the aortic arch and when false lumen decompression through the distal aortic branches are less effective. Compared with ATAD, RTAD has less root involvement, and successful aortic valve resuspension is more likely.

Impact of Thoracic Endovascular Aortic Repair on Pulsatile Circumferential and Longitudinal Strain in Patients With Aneurysm

Purpose: To quantify both pulsatile longitudinal and circumferential aortic strains before and after thoracic endovascular aortic repair (TEVAR), potentially clarifying TEVAR-related complications. Methods: This retrospective study assessed the impact of TEVAR on pulsatile aortic strains through custom developed software and cardiac-gated computed tomography imaging of 8 thoracic aneurysm patients (mean age 71.0±8.2 years; 6 men) performed before TEVAR and during follow-up (median 0.1 months, interquartile range 0.1–5.8). Lengths of the ascending aorta, the aortic arch, and the descending aorta were measured. Diameters and areas were computed at the sinotubular junction, brachiocephalic trunk, left subclavian artery, and the celiac trunk. Pulsatile longitudinal and circumferential strains were quantified as systolic increments of length and circumference divided by the corresponding diastolic values. Results: Average pulsatile longitudinal strain ranged from 1.4% to 7.1%, was highest in the arch (p<0.001), and increased after TEVAR by 77% in the arch (7.1%±2.5% vs 12.5%±5.1%, p=0.04) and by 69% in the ascending aorta (5.6±2.3% vs 9.4±4.4%, p=0.06). Average pulsatile circumferential strain ranged from 3.6% to 5.0% before TEVAR and did not differ significantly throughout the thoracic aorta; there was a nonsignificant increase after TEVAR at the unstented sinotubular junction (5.0%±1.4% vs 6.3%±1.0%, p=0.18), with a significant increase at the celiac trunk (3.6%±1.8% vs 6.2%±1.8%, p=0.02). Pulsatile circumferential strains within stented segments were deemed unreliable due to image artifacts. Conclusion: TEVAR was associated with an increase of pulsatile longitudinal strains (in the arch) and circumferential strains (at the celiac trunk) in unstented aortic segments. These observations suggest increased pulsatile wall stress after TEVAR in segments adjacent to the device, which may contribute to the understanding of stent-graft–related complications such as retrograde dissection, aneurysm formation, and rupture.

Iatrogenic aortic dissection after minimally invasive aortic valve replacement: a case report

BACKGROUND

As minimally invasive cardiac and vascular procedures are on the rise, the incidence of iatrogenic acute aortic dissection (IAAD) will increase. Cardiovascular professionals should be aware about the risk factors, means of prevention and best management options for IAAD in the perioperative setting.

CASE PRESENTATION

We present the successful clinical management of a complicated case of IAAD after minimally invasive aortic valve replacement.

CONCLUSION

High index of suspicion is required for prompt diagnosis of IAAD; collaboration of the whole perioperative team is imperative for management of this catastrophe.

Surgical Management of Peripheral Vascular Manifestations of Loeys-Dietz Syndrome

BACKGROUND

Loeys-Dietz syndrome (LDS) is characterized by a triad of aortic aneurysm, vessel tortuosity, and hypertelorism. LDS patients often harbor additional aneurysms and dissections throughout their vasculature. The optimal management of these additional lesions is poorly understood. Accordingly, we sought to analyze our experience with the peripheral arterial manifestations of LDS.

METHODS

Adult and pediatric LDS patients who sought treatment at a single institution from 2005 to 2015 were retrospectively reviewed. Patients were included if radiographic or clinically documented evidence existed of peripheral artery aneurysm or dissection. Standard univariate analyses were performed.

RESULTS

Eighteen LDS patients (aged 1.3-59.3 years, mean age 27.8 years at diagnosis) with aortic (not including root, ascending, or arch) vascular abnormalities were identified. Average follow-up was 5.2 ± 3.8 years. Fourteen (77.8%) patients had peripheral aneurysms, occurring most frequently in the carotid (35.7%), subclavian (35.7%), and visceral (28.6%) segments. Most patients had multiple peripheral segments involved (average 2, range 1-6). Nine (64%) patients with peripheral involvement underwent repair, for a total of 17 operations (average 1.89 operations per patient, range 1-4). Endovascular techniques were used in 4 operations (23.5%), without technical failures. Among patients requiring surgical repair, a history of abdominal aortic repairs was present in 77.8%, yielding a total of 36 vascular repairs (average 4, range 2-7). Perioperative morbidity was 11.8%, with no reported mortalities. Prior aortic dissection was not associated with peripheral surgical repairs (P = 0.58).

CONCLUSIONS

LDS is an aggressive vasculopathy which commonly affects the peripheral vasculature. Our data suggest that open and endovascular procedures may be safe and effective in the LDS periphery and multiple operations are common. As prior aortic dissection did not predict peripheral arterial involvement in LDS, vigilant peripheral arterial surveillance of LDS is warranted regardless of aortic disease state and may be key to early identification and our treatment success.

Endovascular Stent-Graft Placement in Patients with Stanford Type B Aortic Dissection in China: A Systematic Review

BACKGROUND

Improvements in stent-graft devices and increasing clinical experience with the technique have improved outcomes and expanded clinical indications in patients with Stanford type B aortic dissection (AD) in China. However, the evolution of and modifications to stent grafts have not been reviewed. The aim of this study was to summarize all available published data on technical success, potential benefits, complications, stent evolution, and survival rates associated with endovascular stent-graft placements in patients with Stanford type B AD in China.

METHODS

We performed comprehensive searches of the Chinese-language medical literature in Chinese Biomedical Database, China National Knowledge Infrastructure, and Wanfang Data and of the English-language medical literature in PubMed, Web of Science, and the Cochrane Library. This systematic review was based on all retrospective studies assessing outcomes of Stanford type B AD treated with endovascular stent-graft placement in China.

RESULTS

A total of 153 retrospective studies that included 8,694 cases were analyzed in this study. Procedure success was reported in 99.7 ± 0.1% of patients. Overall complications were reported in 19.1 ± 0.6% of patients. Postoperative endoleaks occurred in 7.2 ± 0.3% of patients. Major complications were reported in 3.2 ± 0.2% of patients, with a neurological complication rate of 1.3 ± 0.1%. Periprocedural stroke occurred more frequently than did paraplegia (0.8 ± 0.1% vs. 0.1 ± 0.04%). Overall complications were significantly greater in patients treated with first-generation stents than in those treated with second-generation stents (25.1 ± 1.2% vs. 9.5 ± 0.9%, P < 0.001). The in-hospital mortality rate was 1.6 ± 0.1%. In addition, 1.8 ± 0.2% of patients died during a mean follow-up period of 29.4 ± 13.5 months. The Kaplan-Meier estimates of the overall survival rate were 99.0 ± 0.1% at 30 days, 98.5 ± 0.2% at 6 months, 98.4 ± 0.2% at 1 year, 98.1 ± 0.2% at 2 years, and 97.9 ± 0.2% at 5 years.

CONCLUSIONS

Endovascular stent-graft placement is feasible and has a high technique success rate as well as favorable neurological complication and survival rates when used to treat Stanford type B AD. The new generation of stent grafts appears to have favorable in-hospital and follow-up outcomes.

Impact of Oversizing on the Risk of Retrograde Dissection After TEVAR for Acute and Chronic Type B Dissection

Purpose: To find a suitable rate of thoracic stent-graft oversizing by exploring its association with the occurrence of retrograde type A dissection (RTAD) after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection. Methods: From January 2013 to June 2014, 203 patients (mean age 55 years; 167 men) with type B aortic dissection underwent TEVAR. The mean rate of oversizing at the proximal landing zone was 10% (range 0%–32%). Patients were stratified into 2 groups based on the degree of oversizing: ≤5% (n=105, mean 1.2%±1.5%) and >5% (n=98, mean 18.5%±2.8%). TEVAR-related complications, including RTAD, stent migration, and type I endoleaks, were analyzed. Results: There were no significant differences in the preoperative proximal landing zone diameters between the groups (31.1 mm for the ≤5% group vs 31.8 mm for the >5% group, p=0.229). The incidence of type I endoleaks over a mean follow-up 15.1±6.4 months was 5.4% [6 (5.7%) in the ≤5% group vs 5 (5.1%) in the >5% group, p=0.847]. The stent migration rate was low in both groups (1% vs 2%, respectively; p=0.521). The occurrence of RTAD [0 in the ≤5% group vs 11 (11.2%) in the >5% group] was significantly associated with the rate of oversizing (p<0.001). Conclusion: The early and midterm outcomes of this study demonstrate that ≤5% oversizing may be a suitable option for thoracic endografts used to treat type B dissection. The smaller rate of oversizing can lower the incidence of RTAD without increasing stent migration or type I endoleak rates.

Delayed Retrograde Ascending Aortic Dissection After Endovascular Repair of Descending Dissection

We report the case of a 34-year-old woman who developed delayed retrograde ascending aortic dissection after previous endovascular repair of her descending thoracic aorta. Preoperative computed tomography imaging specifically highlights the interaction of endograft springs with the dissection flap and surrounding aortic tissues. Intraoperative findings are presented for comparison and further discussion.

Update in the management of type B aortic dissection

Stanford type B aortic dissection (TBAD) is a life-threatening aortic disease. The initial management goal is to prevent aortic rupture, propagation of the dissection, and symptoms by reducing the heart rate and blood pressure. Uncomplicated TBAD patients require prompt medical management to prevent aortic dilatation or rupture during subsequent follow-up. Complicated TBAD patients require immediate invasive management to prevent death or injury caused by rupture or malperfusion. Recent developments in diagnosis and management have reduced mortality related to TBAD considerably. In particular, the introduction of thoracic stent-grafts has shifted the management from surgical to endovascular repair, contributing to a fourfold increase in early survival in complicated TBAD. Furthermore, endovascular repair is now considered in some uncomplicated TBAD patients in addition to optimal medical therapy. For more challenging aortic dissection patients with involvement of the aortic arch, hybrid approaches, combining open and endovascular repair, have had promising results. Regardless of the chosen management strategy, strict antihypertensive control should be administered to all TBAD patients in addition to close imaging surveillance. Future developments in stent-graft design, medical therapy, surgical and hybrid techniques, imaging, and genetic screening may improve the outcomes of TBAD patients even further. We present a comprehensive review of the recommended management strategy based on current evidence in the literature.

Hybrid Repair of an Aortic Arch Aneurysm Using Double Parallel Grafts Perfused by Retrograde Flow in Endovascular Repair Combined With Left Subclavian Artery Surgical Bypass

Despite its invasive nature, open surgical repair is still the first choice to treat aortic arch aneurysms. With the advancement of endovascular technology, thoracic endovascular aortic repair (TEVAR) has gained popularity in treating aortic aneurysms; however, blood flow preservation of the supra-arch branches remains a complicated challenge. This case report describes a hybrid procedure that successfully treated a patient with aortic arch aneurysm by combining the parallel grafts perfused by retrograde flow in the TEVAR procedure and a carotid-subclavian artery bypass.

Risk factors for distal stent graft-induced new entry following endovascular repair of type B aortic dissection

BACKGROUND

Distal stent graft-induced new entry (DSINE) has been increasingly observed following thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD). We seek to identify the risk factors for DSINE following TEVAR in patients with TBAD.

METHODS

Between January 2009 and January 2013, we performed TEVAR for 579 patients with TBAD. The clinical data were retrospectively analyzed with univariate and multivariate analyses to identify the risk factors for DSINE.

RESULTS

Two patients (0.3%) died after the initial TEVAR. Morbidity included spinal cord injury in 2 (0.3%), stroke in 3 (0.5%) and endoleak in 12 (2.1%) patients. Clinical and radiological follow-up was complete in 100% (577/577) averaging 47±16 months. Late death occurred in 6 patients. DSINE occurred in 39 patients (6.7%) at mean 22±17 months after the initial TEVAR, which was managed with re-TEVAR in 25 and medically in 14. At 33±18 months after DSINE, 11 of patients managed medically (11/14) and all patients managed with re-TEVAR (25/25) survived (P=0.048). Freedom from DSINE was 92.7% at 5 years (95% CI: 90.0-94.7%). Using tapered stent grafts with a proximal end 4-8 mm larger than the distal end, TEVAR performed in the acute phase (≤14 days from onset) was associated with a significantly lower incidence of DSINE than TEVAR performed in the chronic phase (4.3%, 7/185 vs. 13.9%, 15/108; P=0.003). Risk factors for DSINE were stent grafts less than 145 mm in length [odds ratio (OR) 2.268; 95% CI: 1.121-4.587; P=0.023] and TEVAR performed in the chronic phase (OR 1.935; 95% CI: 1.004-3.731; P=0.049).

CONCLUSIONS

Our results show that TEVAR performed during the acute phase and using stent grafts longer than 145 mm could decrease the incidence of DSINE in patients with TBAD. Tapered stent grafts with a proximal end 4-8 mm larger than the distal end may be helpful in preventing DSINE after TEVAR performed in the acute phase than TEVAR performed in the chronic phase, due to the difference in mobility of the dissected flap. Expedite repeat TEVAR is recommended to improve the clinical prognosis for patients with DSINE.

Apparatus for Comparison of Pullout Forces for Various Thoracic Stent Grafts at Varying Neck Angulations and Oversizes

BACKGROUND

The purpose of this study is to provide an apparatus for comparison of pullout forces for various thoracic stent grafts at varying neck angulations and oversizes.

METHODS

An in vitro platform capable of performing pullout tests was used on stent grafts in angulated silicone tubes designed for this study (0°, 45°, 90°, and 135° with a 32-mm inner diameter) in a temperature-controlled chamber (37 ± 2°C). Three commercial stent grafts with sizes commonly used in Taiwan (Valiant: 34, 36, 38, and 40 mm; Zenith TX2: 34, 36, 38, and 40 mm; and TAG: 34, 37, and 40 mm) were used, and each size was tested 8 times for each angulation condition.

RESULTS

The mean dislodgement forces (DFs) at 0° angulation within 10-20% oversize were approximately 22.7, 9.6, and 9.0 N for the Valiant, Zenith TX2, and TAG devices, respectively, whereas the mean DFs decreased by 46%, 38%, and 50% to 12.3, 5.9, and 4.5 N when the angulation reached 135°. Regression analysis shows that neck angulation was a significant factor for the Valiant and Zenith TX2 devices (P < 0.0001 and P < 0.0001, respectively) but not for the TAG device (P = 0.483). In addition, oversize and interactions between variables (angulation × oversize) exhibited significant effects on the DFs for all devices (P < 0.0001).

CONCLUSIONS

We successfully built up an apparatus for comparison of pullout forces for various thoracic stent grafts at varying neck angulations and oversizes. With the empirical comparative data of different brand stent grafts under various conditions shown and compared, our findings suggest that aortic neck angulation has a negative correlation with stent-graft fixation. To have better stent-graft fixation and seal in the aortic arch for thoracic endovascular aortic repair, a longer landing zone with cautiously selected oversize is a more suitable selection.

Thoracic Endovascular Repair of Complicated Penetrating Aortic Ulcer

Purpose: To analyze an 11-year single-center experience of treating complicated penetrating aortic ulcer (PAU) using thoracic endovascular aortic repair (TEVAR). Methods: This study included 63 consecutive patients (mean age 69.1±11.5 years; 40 men) with complicated PAU (42 symptomatic, 22 with rupture) who underwent TEVAR between 2002 and 2013. The PAUs were located in the aortic arch (n=11), the descending thoracic aorta (n=43), and the thoracoabdominal aorta (n=9). Results: TEVAR was performed within 14 days of diagnosis in 33 (52.3%) cases (19 ruptures treated immediately); the other 30 (47.6%) patients had an average interval between diagnosis and intervention of 40±39 days. Technical success was 98.4% (62/63). One patient had a type I endoleak after stent-graft repair of a PAU in the aortic arch without great vessel transposition; another procedure was required for carotid-subclavian bypass and proximal stent-graft extension. No patient experienced spinal cord ischemia after TEVAR. Five (7.9%) patients died in-hospital; 3 had severe cardiac complications, 1 died from complications of aortic rupture, and the other succumbed to septic shock. Mean follow-up was 45.6±47.2 months, during which 12 (19.0%) patients needed a secondary intervention because of late endoleaks (n=4, 6.3%) or new complications due to disease progression. Multivariate analysis indicated that a PAU depth >15 mm was an independent predictor of mortality (hazard ratio 6.92, p=0.03). In the biomarker analysis, symptomatic patients had significantly higher D-dimer and troponin levels compared to asymptomatic patients [559.5±460.7 vs 283.2±85.2 µg/L (p=0.016) and 0.22±0.61 vs 0.02±0.03 ng/mL (p=0.04), respectively]. Conclusion: Patients with PAU suffer from underlying severe atherosclerotic disease and have a significant number of cardiovascular comorbidities that lead to relevant mortality and morbidity after TEVAR. As a PAU diameter >15 mm represented high risk for disease progression, these patients may be candidates for early intervention. D-dimer levels may help identify patients at risk and with progression of PAU.

Biomechanical Changes After Thoracic Endovascular Aortic Repair in Type B Dissection

Thoracic endovascular aortic repair (TEVAR) has evolved into an established treatment option for type B aortic dissection (TBAD) since it was first introduced 2 decades ago. Morbidity and mortality have decreased due to the minimally invasive character of TEVAR, with adequate stabilization of the dissection, restoration of true lumen perfusion, and subsequent positive aortic remodeling. However, several studies have reported severe setbacks of this technique. Indeed, little is known about the biomechanical behavior of implanted thoracic stent-grafts and the impact on the vascular system. This study sought to systematically review the performance and behavior of implanted thoracic stent-grafts and related biomechanical aortic changes in TBAD patients in order to update current knowledge and future perspectives.

Endovascular repair of Stanford B aortic dissection using two stent grafts with different sizes

OBJECTIVE

The objective of this study was to introduce a novel strategy for thoracic endovascular aortic repair of Stanford B aortic dissection using two-stent graft implantation (TSI), in which the proximal stent and distal stent with different sizes are sequentially deployed, and to summarize our experience with this technique.

METHODS

A retrospective study was conducted of 72 consecutive patients (61 men; mean age, 55 ± 7 years; range, 41-67 years) with Stanford type B aortic dissection who underwent TSI treatment between January 2012 and May 2013. Among all patients, 43 (59.7%) involved the infrarenal aorta and 29 (40.3%) involved the whole thoracic and abdominal aorta; mean aortic involvement length was 226 ± 13 mm (range, 182-312 mm). Eight cases were for acute dissection (within 2 weeks from onset of symptoms), 11 cases were for chronic dissection (>3 months after initial dissection), and 53 cases were for subacute dissection (between 2 weeks and 3 months). Twenty-two cases (30.6%) were uncomplicated type and 50 cases (69.4%) were complicated type. Follow-up was performed postoperatively at 1 month, 6 months, and yearly thereafter. Technique success, aorta morphology, and procedure-related complications were evaluated.

RESULTS

Technical success was achieved in 100%; 72 pairs of stent grafts (144 thoracic stent grafts) and 10 left subclavian artery chimney stents were used. The mean aortic length coverage by the stent grafts was 197.6 ± 20.3 mm, and mean taper diameter span was 7.5 ± 1.8 mm. All patients were followed up from 6 to 16 months (mean, 10 ± 4 months); 95.8% (69 of 72) had a thrombosed false lumen in the aortic coverage, and the true lumen expanded on average 57% ± 11% (23%-100%). No significant changes were found in aortic diameters of the proximal and distal ends of the two stent grafts and the angles between centerlines of the distal end of the stent and the aorta during follow-up. Procedure-related complications included transient paraplegia (coverage of the left subclavian artery without revascularization and extensive coverage of aorta >220 mm) due to acute spinal cord ischemia (n = 1) and malapposition of the distal stent (primary tear closed, true lumen expansion led to oversize rate insufficient in distal stent diameter; n = 1). No death or malperfusion complications were observed during the perioperative period and follow-up.

CONCLUSIONS

Short-term outcomes showed TSI to be a flexible and effective approach to accurately repair Stanford B aortic dissection that could potentially address the limitations of currently available stent grafts. Further prospective clinical studies are warranted to evaluate its long-term efficacy.

Endovascular Repair of Aortic Dissection in Marfan Syndrome: Current Status and Future Perspectives

Over the last decades, improvement of medical and surgical therapy has increased life expectancy in Marfan patients. Consequently, the number of such patients requiring secondary interventions on the descending thoracic aorta due to new or residual dissections, and distal aneurysm formation has substantially enlarged. Surgical and endovascular procedures represent two valuable options of treatment, both associated with advantages and drawbacks. The aim of the present manuscript was to review endovascular outcomes in Marfan syndrome and to assess the potential role of Thoracic Endovascular Aortic Repair (TEVAR) in this subset of patients.

Endovascular Repair versus Open Repair for Isolated Descending Thoracic Aortic Aneurysm

PURPOSE

To compare the outcomes of thoracic endovascular aortic repair (TEVAR) with those of open repair for descending thoracic aortic aneurysms (DTAA).

MATERIALS AND METHODS

We compared the outcomes of 114 patients with DTAA and proximal landing zones 3 or 4 after TEVAR to those of 53 patients after conventional open repairs. Thirty-day and late mortality were the primary endpoints, and early morbidities, aneurysm-related death, and re-intervention were the secondary endpoints.

RESULTS

The TEVAR group was older and had more incidences of dissecting aneurysm. The mean follow-up was 36±26 months (follow-up rate, 97.8%). The 30-day mortality in the TEVAR and open repair groups were 3.5% and 9.4% (p=0.11). Perioperative stroke and paraplegia incidences were similar between the groups [5.3% vs. 7.5% (p=0.56) and 7.5% vs. 3.5% (p=0.26), respectively]. Respiratory failure occurred more in the open repair group (1.8% vs. 26.4%, p<0.01). The incidence of acute kidney injury requiring dialysis was higher in the open repair group (1.8% vs. 9.4%, p<0.01). The cumulative survival rate was higher in the TEVAR group at 2 to 5 years (79.6% vs. 58.3%, p=0.03). The free from re-intervention was lower in the TEVAR group (65.3% vs. 100%, p=0.02), and the free from aneurysm-related death in the TEVAR and open repair groups were 88.5% and 86.1% (p=0.45).

CONCLUSION

TEVAR is safe and effective for treating DTAAs with improved perioperative and long-term outcomes compared with open repair.

One-stage hybrid procedure without sternotomy for treating thoracic aortic pathologies that involve distal aortic arch: a single-center preliminary study

OBJECTIVE

This study aims to evaluate the initial results of a hybrid procedure without sternotomy for treating descending thoracic aortic disease that involves distal aortic arch. It also intends to report our initial experience in performing this procedure.

METHODS

A total of 45 patients (35 males and 10 females) with descending thoracic aortic disease underwent a hybrid procedure, namely, thoracic endovascular aortic repair (TEVAR) combined with supra-arch branch vessel bypass, in our center from April 2009 to August 2014. Right axillary artery to left axillary artery bypass (n=20) or right axillary artery to left common carotid artery (LCCA) and left axillary artery bypass (n=25) were performed. The conditions of all patients were followed up from the 2(nd) month to the 65(th) month postoperative (mean, 26.0±17.1). Mortality within 30 days, complications such as endoleak after the hybrid procedure, and stenosis or blockage of the bypass graft during the follow-up period was assessed.

RESULTS

All the patients underwent a one-stage procedure. One case of death and one case of cerebral infarction were reported within 30 days. One patient died of the sudden drop in blood pressure during the 2(nd) day of operation. Meanwhile, another patient suffered from cerebral infarction. Two patients underwent open surgery, and one of them had to undergo a second TEVAR during the follow-up period. Moreover, endoleak occurred in two patients and a newly formed intimal tear was observed in one patient. Overall, 93.2% of the patients survived without any complication related to the hybrid procedure.

CONCLUSIONS

Initial results suggest that the one-stage hybrid procedure is a suitable therapeutic option for thoracic aortic pathologies that involve distal aortic arch. However, this procedure is not recommended for type-B aortic dissection, in which a tear is located in the greater curvature or near the left subclavian artery (LSA), because of the high possibility of endoleak occurrence.