Continued favorable results with open surgical repair of type IV thoracoabdominal aortic aneurysms

Endovascular Repair of Thoracoabdominal Aortic Aneurysm: A Brief Review

Thoracoabdominal aortic aneurysms (TAAAs) are complex and if untreated have high mortality and morbidity rates. Open surgical repair is the historical treatment approach; however, postoperative complications remain high with spinal cord ischemia notably one of the more serious and common complications. The avoidance of thoracotomy or laparotomy with the advent of endovascular aortic repair (EVAR) and thoracic endovascular aortic repair (TEVAR) have decreased the morbidity and mortality with TAAA repair, especially in patients with significant comorbidities such as a history of aortic surgery, underlying cardiac disease, and chronic obstructive pulmonary disease. Endovascular treatment options have grown to include fenestrated EVAR, multibranched EVAR, and physician-modified fenestration stent grafts. These techniques have achieved lower mortality rates than traditional open repair, but complications such as limb ischemia, spinal cord ischemia, and long-term durability must be considered. This review provides an overview of the most common endovascular techniques for TAAAs as well as short- and midterm outcomes.

Independent associations with early mortality after open repair of Crawford extent IV thoracoabdominal aortic aneurysms

OBJECTIVE

We aimed to identify outcomes and factors that independently associate with early mortality after open repair of Crawford extent IV thoracoabdominal aortic aneurysms, defined as aneurysms confined to the segment below the diaphragm.

METHODS

This retrospective analysis included 721 extent IV thoracoabdominal aortic aneurysm repairs performed in our institution from 1986 to 2021. Indications for repair were aneurysm without dissection in 627 cases (87.0%) and aortic dissection in 94 cases (13.0%). Overall, 466 patients (64.6%) were symptomatic preoperatively; 124 (17.2%) procedures were performed in patients with acute presentation, including 58 (8.0%) ruptured aneurysms.

RESULTS

Operative death occurred after 49 (6.8%) repairs. Persistent renal failure necessitating dialysis occurred after 43 (6.0%) repairs. Binary logistic regression modeling revealed that previous extent II thoracoabdominal aortic aneurysm repair, chronic kidney disease, previous myocardial infarction, urgent or emergency repair, and longer crossclamp times during surgery were independently associated with operative mortality. Among early survivors (n = 672), competing risk analysis revealed that cumulative incidence of mortality and reintervention rates at 10 years were 74.8% (95% confidence interval, 71.4%-78.5%) and 3.3% (95% confidence interval, 2.2%-5.1%), respectively.

CONCLUSIONS

Although patient comorbidities contributed to operative mortality, factors associated with the repair, such as urgent or emergency status, the duration of aortic crossclamping, and certain types of complex reoperation, also played prominent roles. Patients who survive the operation can expect a durable repair that usually is free from late reintervention. Expanding our collective knowledge regarding patients who undergo open repair of extent IV thoracoabdominal aortic aneurysms will enable clinicians to establish best practices and improve patient outcomes.

Efficacy and Safety of Endovascular Fenestrated and Branched Grafts Versus Open Surgery in Thoracoabdominal Aortic Aneurysm Repair: An Updated Systematic Review, Meta-analysis, and Meta-regression

OBJECTIVE

To provide an updated systematic review and meta-analysis with meta-regression of efficacy and safety of fenestrated/branched endovascular repair of thoracoabdominal aortic aneurysms (TAAAs) compared with open repair.

BACKGROUND

Endovascular repair of TAAAs may be a promising alternative to open surgery by reducing invasiveness and expanding the eligible population, but evidence remains limited.

METHODS

We applied "Prepared Items for Systematic Reviews and Meta-analysis" guidelines to retrieve, quantitatively pool, and critically evaluate the efficacy and safety (including 30-day mortality, reintervention, spinal cord injury [SCI], and renal injury) of both approaches. Original studies were retrieved from PubMed, Embase, and Cochrane Library until April 20, 2022, excluding papers reporting <10 patients. Pooled proportions and means were determined using a random-effect model. Heterogeneity between studies was evaluated with I2 statistics.

RESULTS

Sixty-four studies met the predefined inclusion criteria. Endovascular cohort patients were older and had higher rates of comorbidities. Endovascular repair was associated with similar proportions of mortality (0.07, 95% confidence intervals [CI]: 0.06-0.08) compared with open repair (0.09, 95% CI: 0.08-0.12; P = 0.22), higher proportions of reintervention (0.19, 95% CI: 0.13-0.26 vs 0.06, 95% CI: 0.04-0.10; P < 0.01), similar proportions of transient SCI (0.07, 95% CI: 0.05-0.09 vs 0.06, 95% CI: 0.05-0.08; P = 0.28), lower proportions of permanent SCI (0.04, 95% CI: 0.03-0.05 vs 0.06, 95% CI: 0.05-0.07; P < 0.01), and renal injury (0.08, 95% CI: 0.06-0.10 vs 0.13, 95% CI: 0.09-0.17; P = 0.02). Results were affected by high heterogeneity and potential publication bias.

CONCLUSIONS

Despite these limitations and the lack of randomized trials, this meta-analysis suggests that endovascular TAAA repair could be a safer alternative to the open approach.

Open extent IV thoracoabdominal aneurysm repair: 22-year experience of the Scottish National Service

BACKGROUND

Since 1999, the Scottish National Service for Thoracoabdominal Aneurysms has offered repair of thoracoabdominal aneurysms (TAAAs) to a population of 5.5 million people. The open operation most commonly performed by the service is the extent IV TAAA repair.

METHODS

All extent IV open TAAA repairs performed at the Scottish National Service for TAAAs from June 1999 until April 2021 were evaluated for clinical features, technical details, and clinical outcomes. The primary outcome measure was 30-day mortality; secondary outcomes included short-term (90 days, 6 months, 1 and 2 years) and long-term (5 and 10 years) survival, perioperative complications, and reintervention. Survival was assessed using Kaplan-Meier analysis.

RESULTS

Some 248 patients underwent extent IV TAAA repair, with elective surgery in 204 (82.3 per cent). A totally abdominal transperitoneal approach was used for all patients, with a median visceral ischaemia time of 40 (i.q.r. 35-48) min. Overall, 18 patients (7.3 per cent) died within 30 days. The proportion of patients surviving at 90 days, 6 months, 1, 2, 5, and 10 years was 0.91, 0.90, 0.89, 0.85, 0.72, and 0.41, respectively. Ten patients (4.0 per cent) required a reintervention while in hospital, four (1.6 per cent) experienced permanent spinal cord ischaemia, 19 (7.9 per cent) required temporary renal replacement therapy (RRT), and four (1.6 per cent) required permanent RRT.

CONCLUSION

Open extent IV TAAA repair performed in a high-volume national centre is associated with favourable short- and long-term survival, and acceptable complication rates.

Results of cryopreserved arterial allograft replacement for thoracic and thoracoabdominal aortic infections

BACKGROUND

Primary and secondary thoracic aortic infections are rare but associated with high morbidity and mortality. There is currently no consensus on their optimal treatment. Arterial allografts have been shown to be resistant to bacterial colonization. Complete excision of infected material, especially synthetic grafts, combined with in situ aortic repair is considered the best treatment of abdominal aortic infections. The aim of this study was to assess the management of thoracic and thoracoabdominal aortic infections using arterial allografts.

METHODS

Between January 2009 and December 2017, all patients with thoracic and thoracoabdominal aortic native or graft infections underwent complete excision of infected material and in situ arterial allografting. The end points were the early mortality and morbidity rates and early and late rates of reinfection, graft degeneration, and graft-related morbidity.

RESULTS

Thirty-five patients with a mean age of 65.6 ± 9.2 years were included. Twenty-one (60%) cases experienced graft infections and 14 (40%) experienced native aortic infections. Eight (22.8%) patients had visceral fistulas: 5 (14.4%) prosthetic-esophageal, 1 (2.8%) prosthetic-bronchial, 1 (2.8%) prosthetic-duodenal, and 1 (2.8%) native aortobronchial. In 12 (34.3%) cases, only the descending thoracic aorta was involved; in 23 (65.7%) cases, the thoracoabdominal aorta was involved. Fifteen (42.8%) patients died during the first month or before discharge: 5 of hemorrhage, 4 of multiorgan failure, 3 of ischemic colitis, 2 of pneumonia, and 1 of anastomotic disruption. Eleven (31.5%) patients required early revision surgery: 6 (17.1%) for nongraft-related hemorrhage, 3 (8.6%) for colectomy, 1 (2.9%) for proximal anastomotic disruption, and 1 (2.9%) for tamponade. One (2.9%) patient who died before discharge experienced paraplegia. One (2.9%) patient experienced stroke. Six (17.1%) patients required postoperative dialysis. Among them, four died before discharge. The mean length of stay in the intensive care unit was 11 ± 10.5 days; the mean length of hospital stay was 32 ± 14 days. During a mean follow-up of 32.3 ± 23.7 months, three allograft-related complications occurred in survivors (15% of late survivors): one proximal and one distal false aneurysm with no evidence of reinfection and one allograft-enteric fistula. The 1-year and 2-year survival rates were 49.3% and 42.5%, respectively.

CONCLUSIONS

Although rare, aortic infections are highly challenging. Surgical management includes complete excision of infected tissues or grafts. Allografts offer a promising solution to aortic graft infection because they appear to resist reinfection; however, the grafts must be observed indefinitely because of the risk of late graft complications.

The Long-term Fate of Renal and Visceral Vessel Reconstruction After Open Thoracoabdominal Aortic Aneurysm Repair

OBJECTIVES

In the ever-advancing era of endovascular thoracoabdominal aneurysm (TAAA) repair, understanding long-term patency of renovisceral reconstructions after open TAAA repair provides important benchmarks.

METHODS

Institutional open TAAA repair patient data were queried. Patients dying during index admission or with incomplete operative detail were excluded. Visceral and renal reconstructions were categorized as bypass, incorporation into a proximal or distal beveled aortic anastomosis, inclusion button, Carrel patch, or hybrid stent along with endarterectomy/stent adjuncts. Axial imaging or angiography determined long-term patency. Vessel event was defined as new occlusion or reintervention after repair. Overall time-to-event analysis was performed as well as separate analyses for each vessel (Celiac, SMA, right renal, left renal) by reconstruction type utilizing Kaplan-Meier methods. Log-rank testing was employed to compare reconstructive strategies.

RESULTS

Over 28-years, 604 repairs [Type I 106(18%), Type II 73(12%), Type III 195(32%), Type IV 230(38%)] were identified. Follow-up (median 500 days) was available in 410/570(72%) Celiac, 406/573(71%) SMA, 379/532(71.2%) right renal, and 370/515(72%) left renal reconstructions. There were five celiac, one SMA, eight right renal, and ten left renal events. No type of reconstruction or adjunct was significantly associated with event. Overall 5-year patency of all renal/visceral reconstructions was 94% (95%CI [90%-96%]). Estimated 5-year patency of the Celiac, SMA, left renal, and right renal were similar, and were 99%, 100%, 97%, and 96%, respectively (p = .09).

CONCLUSIONS

Visceral and renal long-term patency after open TAAA repair is excellent regardless of reconstructive technique. No differences are appreciated even when target vessel disease is addressed at the time of reconstruction. These findings continue to substantiate the effective long-term durability of open TAAA repair and are particularly germane to the ongoing evolution of endovascular strategies.

Female Sex Portends Worse Long-Term Survival after Open Type I-III Thoracoabdominal Aneurysm Repair

BACKGROUND

Although outcomes after infrarenal abdominal aortic aneurysm surgery are worse in females, sex-specific differences in outcomes after open thoracoabdominal aortic aneurysm (TAAA) repair are less clear. The goal of this study was to identify sex-based disparities in short- and long-term outcomes after open type I-III TAAA surgery.

METHODS

All open type I-III TAAA repairs performed from 1987 to 2015 were evaluated using an institutional database. Charts were retrospectively evaluated for perioperative outcomes: major adverse events (MAEs), in-hospital death, and long-term survival. Univariate analysis was performed using the Fisher's exact test for categorical variables and the Wilcoxon rank-sum test for continuous variables. Logistic regression was used for in-hospital end points; survival analyses were performed with Cox proportional hazards modeling and Kaplan-Meier techniques. Sensitivity analyses were performed for relevant multivariable models, one with ruptures removed and another evaluating only repairs performed before 2006 to account for any selection bias due to wider use of complex endovascular technology.

RESULTS

Five-hundred sixteen patients underwent open type I-III TAAA repair during the study period. Females accounted for 54.3% (n = 280) of the cohort. Women were older, less likely to have a chronic dissection etiology, more likely to present with a symptomatic/ruptured lesion, and had a lower admission creatinine than men. Perioperative death occurred in 23 men (9.8%) and 19 women (6.8%) (P = 0.26); 133 women (47.3%) and 116 men (49.2%) suffered an MAE (P = 0.72). Multivariable analyses revealed no sex-based difference in perioperative death (Female sex adjusted odds ratio (AOR): 0.72, 95% confidence interval (CI): 0.4-1.4, P = 0.34) or MAE (AOR: 1.0 CI: 0.7-1.5, P = 0.82). Unadjusted survival at five years was 50% for women and 67% for men (log-rank P < 0.001). Female sex was an independent predictor of decreased survival (hazard ratio (HR): 1.5 95% CI: 1.2-1.9, P = 0.001) when adjusted for age, aneurysm extent, creatinine, chronic obstructive pulmonary disease, and ruptures. After removing all ruptures, female sex remained nonpredictive of perioperative death (AOR: 1.1, 95% CI 0.5-2.5, P = 0.75) or MAE (AOR: 1.2, CI: 0.8-1.9, P = 0.31) and predictive of decreased long-term survival (HR: 1.5, 95% CI: 1.2-2.0, P = 0.001).

CONCLUSIONS

Those undergoing open type I-III TAAA repair have similar rates of perioperative mortality and MAEs, regardless of sex. However, female sex is an independent risk factor for decreased long-term survival.

Sex-related outcomes after open type IV thoracoabdominal aortic aneurysm repair

OBJECTIVE

Although outcomes after infrarenal abdominal aortic aneurysm surgery are worse in women, sex-specific differences in outcomes after open type IV thoracoabdominal aortic aneurysm (TAAA) surgery are undefined. The goal of this study was to define sex-based disparities in short- and long-term outcomes after open type IV TAAA surgery.

METHODS

All open type IV TAAA repairs performed during 27 years were evaluated using a single institutional database. Charts were retrospectively evaluated for major adverse events (in-hospital death, other major in-hospital complication) and long-term complications (graft- and aortic-related events and death). Univariate analyses were performed using the Fisher's exact test for categorical variables and Wilcoxon rank-sum testing for continuous variables. Logistic multivariable regression was used for the in-hospital end points death and major complication, and survival analyses were performed with Cox proportional hazards modeling and Kaplan-Meier techniques.

RESULTS

During the 27-year study period, 234 patients had an open type IV TAAA repair; 85 were female and 149 were male. There were 26 (17.5%) men and 16 (18.8%) women who suffered a major in-hospital complication/death. There were eight (3.4%) in-hospital deaths, all occurring in men. Unadjusted survival at 5 years was 67.9% for women and 58.4% for men. Multivariable analyses revealed no sex-based difference in combined major in-hospital events and death (female: odds ratio [OR], 1.8; confidence interval [CI], 0.83-4.0; P = .13) or any complication (OR, 1.0; CI, 0.55-1.8; P = .99). However, women were less likely than men to be discharged to home (OR, 0.28; CI, 0.13-0.60; P = .001) and had decreased survival compared with men after discharge (hazard ratio, 2.1; CI, 1.2-3.5; P = .008).

CONCLUSIONS

No sex-based differences were found for the in-hospital outcomes of death or major complication after open type IV TAAA repair. However, women are less likely than men to be discharged home. Among those who survive the index operation, female sex portends decreased survival following discharge after repair.

Early Postoperative Renal Dysfunction Predicts Long-Term Renal Function Degradation after Type IV Thoracoabdominal Aortic Aneurysm Surgical Repair

BACKGROUND

Type IV thoracoabdominal aortic aneurysm surgical repair is often complicated by postoperative acute kidney injury. The aim was to evaluate early renal injury influence on long-term renal function.

METHODS

All type IV thoracoabdominal surgical repair performed between January 2000 and January 2014 in our tertiary hospital were included in this retrospective observational study. All procedures were performed through a retroperitoneal approach with at least suprarenal aortic cross-clamping. Cold Ringer Lactate was used to perfuse the kidneys. Serum creatinine (Scr.) and glomerular filtration rate (GFR) were recorded preoperatively, daily until discharge and at least annually during follow-up. Postoperative renal dysfunction was classified using the RIFLE score. Predictors of long-term renal decline were identified by logistic regression and a Cox model.

RESULTS

Of total, 80 patients were included. Aortic clamping level was suprarenal (10%), supramesenteric (37%) or supracoeliac (53%). Ischemic durations were 29 ± 9 min for the gastrointestinal tract and the right kidney, 54 ± 28 min for the left kidney. Three patients died postoperatively. At discharge, 31 (38.8%) patients did not have a postoperative renal impairment (RIFLE-), compared with 49 (61.2%) who had a renal dysfunction (RIFLE+). GFR was 89 ± 29 ml/min vs 68 ± 37 ml/min, respectively (P < 0.01). In the RIFLE + group, Scr. was increased by x1.5 (Risk) for 22 patients, x2 (Injury) for 19 patients, and ×3 (Failure) for 8 patients. Mean follow-up was 59 months. Eighteen patients died, and 2 patients started permanent dialysis at 46 and 118 months during follow-up. The only predictive factor of long-term GFR degradation was a postoperative GFR below 45 ml/min (OR: 16.5; 95%; P < 0.001).

CONCLUSIONS

Postoperative renal dysfunction was a frequent complication, associated with long-term renal function degradation.

Current status of endovascular treatment for thoracoabdominal aortic aneurysms

Open surgical repair (OSR) for thoracoabdominal aortic aneurysms (TAAAs) is maximally invasive and associated with high rates of operative mortality and perioperative complications including spinal cord ischemia (SCI), despite improvements in surgical techniques and perioperative care. Elderly patients, patients with a history of aortic surgery, and patients with severe comorbidities are often considered ineligible for this surgery and endovascular treatment may be their only treatment option. Total endovascular aneurysm repair (t-EVAR) without debranching surgery does not require thoracotomy and laparotomy and could improve the outcomes of these patients. t-EVAR includes fenestrated EVAR (f-EVAR), multi-branched EVAR (b-EVAR), and physician-modified fenestration endograft (PMFG). Although these techniques have achieved lower mortality rates than OSR, there are concerns about perioperative complications including limb ischemia, SCI, and long-term outcomes such as endograft migration and endoleaks (ELs). This article provides an overview of available endovascular devices for TAAAs and reviews the short and mid-term results of t-EVAR, as well as alternative options.

Systematic review of contemporary outcomes of endovascular and open thoracoabdominal aortic aneurysm repair

OBJECTIVE

The purpose of the study was to provide a systematic review of the literature reporting the contemporary early outcomes after endovascular and open repair of thoracoabdominal aortic aneurysms (TAAAs).

METHODS

MEDLINE and Embase were searched for studies from January 2006 to March 2018 that reported either endovascular (using branched or fenestrated endografts) or open repair of TAAA in at least 10 patients. Outcomes of interest included perioperative mortality, spinal cord injury (SCI), renal failure requiring dialysis, and stroke. Pooled proportions were determined using a random-effects model.

RESULTS

The analysis included 71 studies, of which 24 and 47 reported outcomes after endovascular and open TAAA repair, respectively. Endovascular cohort patients were older and had higher rates of coronary artery disease, chronic obstructive pulmonary disease, and diabetes. Endovascular repair was associated with higher rates of SCI (13.5%; 95% confidence interval [CI], 10.5%-16.7%) compared with open repair (7.4%; 95% CI, 6.2%-8.7%; P < .01) but similar rates of permanent paralysis (5.2% [95% CI, 3.8%-6.7%] vs 4.4% [95% CI, 3.3%-5.6%]; P = .39), lower rates of postoperative dialysis (6.4% [95% CI, 3.2%-9.5%] vs 12.0% [95% CI, 8.2%-16.3%]; P = .03) but similar rates of being discharged on permanent dialysis (3.7% [95% CI, 2.0%-5.9%] vs 3.8% [95% CI, 2.9%-5.3%]; P = .93), a trend to lower stroke (2.7% [95% CI, 1.9%-3.6%] vs 3.9% [95% CI, 3.0%-4.9%]; P = .06), and similar perioperative mortality (7.4% [95% CI, 5.9%-9.1%] vs 8.9% [95% CI, 7.2%-10.9%]; P = .21).

CONCLUSIONS

This systematic review summarizes the contemporary literature results of endovascular and open TAAA repair. Endovascular repair studies included patients with more comorbidities and were associated with higher rates of SCI but similar rates of permanent paraplegia, whereas open repair studies had higher rates of postoperative dialysis but similar rates of being discharged on permanent dialysis. Perioperative mortality rates were similar. Universally adopted reporting standards for patient characteristics, outcomes, and the conduct of contemporary comparative studies will allow better assessment and comparisons of the risks associated with the two surgical treatment options for TAAA.

Therapeutic hypothermia attenuates paraplegia and neuronal damage in the lumbar spinal cord in a rat model of asphyxial cardiac arrest

Spinal cord ischemia can result from cardiac arrest. It is an important cause of severe spinal cord injury that can lead to serious spinal cord disorders such as paraplegia. Hypothermia is widely acknowledged as an effective neuroprotective intervention following cardiac arrest injury. However, studies on effects of hypothermia on spinal cord injury following asphyxial cardiac arrest and cardiopulmonary resuscitation (CA/CPR) are insufficient. The objective of this study was to examine effects of hypothermia on motor deficit of hind limbs of rats and vulnerability of their spinal cords following asphyxial CA/CPR. Experimental groups included a sham group, a group subjected to CA/CPR, and a therapeutic hypothermia group. Severe motor deficit of hind limbs was observed in the control group at 1 day after asphyxial CA/CPR. In the hypothermia group, motor deficit of hind limbs was significantly attenuated compared to that in the control group. Damage/death of motor neurons in the lumbar spinal cord was detected in the ventral horn at 1 day after asphyxial CA/CPR. Neuronal damage was significantly attenuated in the hypothermia group compared to that in the control group. These results indicated that therapeutic hypothermia after asphyxial CA/CPR significantly reduced hind limb motor dysfunction and motoneuronal damage/death in the ventral horn of the lumbar spinal cord following asphyxial CA/CPR. Thus, hypothermia might be a therapeutic strategy to decrease motor dysfunction by attenuating damage/death of spinal motor neurons following asphyxial CA/CPR.

Contemporary strategies for repair of complex thoracoabdominal aortic aneurysms: real-world experiences and multilayer stents as an alternative

Thoracoabdominal aortic aneurysms (TAAA) present special challenges for repair due to their extent, their distinctive pathology, and the fact that they typically cross the ostia of one or more visceral branch vessels. Historically, the established treatment for TAAA was open surgical repair, with the first procedure reported in 1955. Endovascular repair of TAAA with fenestrated and/ or branched endografts, has been studied since the beginning of the current century as a means of mechanical aneurysm exclusion. More recently, flow modulator stents have been employed with the aim at reducing shear stress on aortic aneurysmal wall. In this review we present technical and main results of these techniques, based on literature review and personal experience.

Treatment of Abdominal Aortic Pathology

Abdominal aortic pathology is a diverse topic, ranging through a broad span of possible pathologies. The treatment options are equally vast, particularly with the ever-expanding endovascular techniques. In this article, we discuss management strategies for abdominal aortic aneurysms and aortic occlusive disease, because they represent some of the most common pathologies encountered in clinical scenarios.

Left heart bypass for thoracoabdominal aortic aneurysm repair: technical aspects

There are different surgical techniques for providing circulatory support during the repair of thoracoabdominal aortic aneurysms. They all aim at reducing the afterload of the heart and the preservation of distal organ perfusion. Partial or total extracorporeal circulation with or without cooling and left heart bypass (LHB) are actually the most used surgical approaches. The objective of this study was to describe and comment on the technical aspects of the LHB. We briefly describe our results and put them into perspective based on the current literature.

Long-term outcomes in thoracoabdominal aortic aneurysm repair for chronic type B dissection

INTRODUCTION

Open repair for chronic aortic dissection remains a challenging surgical option. Different centers report diverse experiences and outcomes pertaining to thoracoabdominal aortic aneurysm repair (TAAAR) for chronic type B dissection. We highlight our center's experience and results on a background of published literature and current evidence.

METHODS

We reviewed 214 open TAAAR performed between October 1998 and February 2014. Of these, chronic type B dissection was present in 62 (29.0%) patients. We reviewed these patients in terms of demographics, operative characteristics and outcomes. Thirteen (21.0%) patients had surgery on the descending thoracic aorta [Category A =2 (3.2%), B =0 (0%), C =11 (17.7%)] and 49 (79.0%) in the thoracoabdominal thoracic aorta [Crawford extent I =5 (8.1%), extent II =39 (62.9%), extent III =4 (6.5%), extent IV =1 (1.6%)]. Left heart bypass was used in 12 (19.4%) patients.

RESULTS

The composite in-hospital endpoint, adverse outcome-defined as operative death, renal failure necessitating dialysis at discharge, stroke, or permanent paraplegia or paraparesis-occurred after 28 (45.2%) procedures. There were 14 (22.6%) operative deaths. In-hospital mortality was seven (16.3%) out of 43 elective patients, and increased to seven (36.8%) of the 19 non-elective ones. Permanent paraplegia or paraparesis occurred after two (3.2%) cases, stroke occurred after seven (11.3%) and renal failure requiring dialysis occurred after 16 (25.8%). Mean follow-up time was 3.2 years and actuarial 5-year mortality was 27.4% [nine (14.5%) elective and eight (12.9%) non-elective patients].

CONCLUSIONS

TAAAR in chronic type B dissection carries a substantial risk of early adverse outcomes. The results could be well alleviated with cases directed towards specialized regional and supra-regional centers. Although the endovascular approaches offer relatively low mortality and morbidity, there is a lack of long-term data and guidelines on their use. There is a need for a multidisciplinary international registry on the management of thoracoabdominal aortic aneurysms and dissection. This would provide a degree of guidance on relevant clinical and surgical judgments and outcomes.

Role of the TLR4 pathway in blood-spinal cord barrier dysfunction during the bimodal stage after ischemia/reperfusion injury in rats

Background

Spinal cord ischemia-reperfusion (I/R) involves two-phase injury, including an initial acute ischemic insult and subsequent inflammatory reperfusion injury, resulting in blood-spinal cord barrier (BSCB) dysfunction involving the TLR₄ pathway. However, the correlation between TLR₄/MyD₈₈-dependent and TLR₄/TRIF-dependent pathways in BSCB dysfunction is not fully understood. The aim of this study is to characterize inflammatory responses in spinal cord I/R and the events that define its clinical progression with delayed neurological deficits, supporting a bimodal mechanism of injury.

Methods

Rats were intrathecally pretreated with TAK-242, MyD₈₈ inhibitory peptide, or Resveratrol at a 12 h interval for 3 days before undergoing 14-minute occlusion of aortic arch. Evan’s Blue (EB) extravasation and water content were detected at 6, 12, 18, 24, 36, 48, and 72 h after reperfusion. EB extravasation, water content, and NF-κB activation were increased with time after reperfusion, suggesting a bimodal distribution, as maximal increasing were detected at both 12 and 48 h after reperfusion. The changes were directly proportional to TLR₄ levels determined by Western blot. Double-labeled immunohistochemical analysis was also used to detect the relationship between different cell types of BSCB with TLR₄. Furthermore, NF-κB and IL-1β were analyzed at 12 and 48 h to identify the correlation between MyD₈₈-dependent and TRIF-dependent pathways.

Results

Rats without functional TLR₄ and MyD₈₈ attenuated BSCB leakage and inflammatory responses at 12 h, suggesting the ischemic event was largely mediated by MyD₈₈-dependent pathway. Similar protective effects observed in rats with depleted TLR₄, MyD₈₈, and TRIF receptor at 48 h infer that the ongoing inflammation which occurred in late phase was mainly initiated by TRIF-dependent pathway and such inflammatory response could be further amplified by MyD₈₈-dependent pathway. Additionally, microglia appeared to play a major role in early phase of inflammation after I/R injury, while in late responding phase both microglia and astrocytes were necessary.

Conclusions

These findings indicate the relevance of TLR₄/MyD₈₈-dependent and TLR₄/TRIF-dependent pathways in bimodal phases of inflammatory responses after I/R injury, corresponding with the clinical progression of injury and delayed onset of symptoms. The clinical usage of TLR₄ signaling inhibitors at different phases may be a therapeutic option for the prevention of delayed injury.

Results of open thoracoabdominal aortic aneurysm repair

BACKGROUND

Open surgical repair of thoracoabdominal aortic aneurysms (TAAAs) enables the effective replacement of the diseased aortic segment and reliably prevents aneurysm rupture. However, these operations also carry substantial risk of perioperative morbidity and mortality, principally caused by the associated ischemic insult involving the spinal cord, kidneys, and other abdominal viscera. Here, we describe the early outcomes of a contemporary series of open TAAA repairs.

METHODS

We reviewed the outcomes of 823 open TAAA repairs performed between January 2005 and May 2012. Of these, 209 (25.4%) were Crawford extent I repairs, 264 (32.1%) were extent II, 157 (19.1%) were extent III, and 193 (23.5%) were extent IV. Aortic dissection was present in 350 (42.5%) cases, and aneurysm rupture was present in 37 (4.5%). Adjuncts used during the procedures included cerebrospinal fluid drainage in 639 (77.6%) cases, left heart bypass in 430 (52.2%), and cold renal perfusion in 674 (81.9%).

RESULTS

The composite endpoint, adverse outcome-defined as operative death, renal failure that necessitated dialysis at discharge, stroke, or permanent paraplegia or paraparesis-occurred after 131 (15.9%) procedures. There were 69 (8.4%) operative deaths. Permanent paraplegia or paraparesis occurred after 42 (5.1%) cases, stroke occurred after 27 (3.3%), and renal failure necessitating permanent dialysis occurred after 45 (5.5%).

CONCLUSIONS

Although open surgical repair of the thoracoabdominal aorta can be life-saving to patients at risk for fatal aneurysm rupture, these operations remain challenging and are associated with substantial risk of early death and major complications. Additional improvements are needed to further reduce the risks associated with TAAA repair, particularly as increasing numbers of patients with advanced age and multiple or severe comorbidities present for treatment.

The fate of untreated concomitant suprarenal aortic aneurysms after endovascular aneurysm repair of infrarenal aortic aneurysms

OBJECTIVE

Many patients treated with endovascular aortic repair (EVAR) have a concomitant suprarenal abdominal aortic aneurysm (sAAA). The natural history of these sAAAs and whether they require intervention after EVAR is unknown.

METHODS

We identified 470 patients from the M2S database (M2S Inc, West Lebanon, NH) as having an infrarenal AAA (iAAA) with a concomitant sAAA (diameter, 2.9-4.7 cm). The analysis included 217 patients with preoperative computed tomography angiography and follow-up imaging of ≥12 months. Patients who did not undergo EVAR (n = 65) served as a control. Patients with EVAR were subdivided into 90 with suprarenal fixation (SR) and 62 with infrarenal fixation (IR). Standard measurements from the M2S images were extracted, and growth rates were calculated for different abdominal aortic segments.

RESULTS

The average follow-up was 33.0 ± 18.8 months. The average sAAA initial size and growth rate were 34.6 ± 3.0 and 0.6 ± 1.1 mm/y for SR, 34.0 ± 3.3 and 0.6 ± 1.3 mm/y for IR, and 36.6 ± 3.4 and 1.2 ± 1.5 mm/y for controls (SR vs IR, P > .05; SR or IR vs control, P < .05). After EVAR, two of 152 (1.3%) sAAAs grew to ≥ 50 mm, which was not statistically different from four of 65 (6.2%) in the control group (P = .07). At 48 months, the Kaplan-Meier freedom from sAAA growth to ≥ 50 mm was 99.3% for patients undergoing EVAR and 95.2% for controls (P = .061). Patients with starting sAAAs sized ≥ 40 mm had a higher growth rate (1.4 ± 2.1 mm/y) and frequency of growth to ≥50 mm (14.3%) than patients with starting sAAAs sized <40 mm (0.7 ± 1.2 mm/y and 1.5%; P < .05).

CONCLUSIONS

Isolated treatment of iAAAs via EVAR with a concomitant sAAA is acceptable because endografts with or without SR do not affect sAAA growth rates. Routine EVAR follow-up is sufficient for sAAAs of <40 mm, and more intensive follow-up should be considered for sAAAs of 40 to 50 mm. For sAAAs approaching 50 mm, an endograft with IR should be considered in case sAAA repair is required in the future.

Temporary extracorporeal axillo-iliac vascular prosthesis shunt in open repair of a pararenal aortic aneurysm

INTRODUCTION

When a long aortic clamp time is expected or when upper body to lower body collateral arteries are sparse, temporary lower body perfusion may be needed to reduce ischemic injury during supraceliac clamping in open repair of pararenal aortic aneurysms. The use of conventional extracorporeal perfusion techniques carry extra risks and is not in the armamentarium of most vascular surgeons. An axillo-femoral or -iliac shunt using a vascular prosthesis does not require the same degree of anticoagulation and causes less activation of blood components.

PRESENTATION OF CASE

A patient, who had extensive vascular stenotic disease and large bowel ischemia, was operated on for a pararenal aortic aneurysm while the lower body was perfused via a temporary extracorporeal vascular prosthesis axillo-iliac shunt. Copious backbleeding encountered while suturing the proximal anastomosis testified to the efficacy of the temporary shunt. A left hemicolectomy had to be performed for gangrene of the sigmoid colon and he needed 2 days of respiratory support; otherwise the postoperative course was uneventful.

DISCUSSION

In our case more ischemic injury than that observed might have been expected without the temporary bypass but significant backbleeding may have negated some of the beneficial effect of the shunt.

CONCLUSION

A temporary axillo-femoral or -iliac shunt prevents lower limb ischemia and provides an ample amount of collateral blood flow to the torso. It does not need to be buried subcutaneously as previously described. Occlusive balloons should be used where possible to prevent backbleeding and to further increase available collateral blood supply.

Intrathecal transplantation of bone marrow stromal cells attenuates blood-spinal cord barrier disruption induced by spinal cord ischemia-reperfusion injury in rabbits

OBJECTIVE

Intrathecal administration of bone marrow stromal cells has been found to produce beneficial effects on ischemia-reperfusion injury to the spinal cord. The blood-spinal cord barrier is critical to maintain spinal cord homeostasis and neurologic function. However, the effects of bone marrow stromal cells on the blood-spinal cord barrier after spinal cord ischemia-reperfusion injury are not well understood. This study investigated the effects and possible mechanisms of bone marrow stromal cells on blood-spinal cord barrier disruption induced by spinal cord ischemia-reperfusion injury.

METHODS

This was a prospective animal study conducted at the Central Laboratory of the First Affiliated Hospital, China Medical University. The study used 81 Japanese white rabbits (weight, 1.8-2.6 kg). Spinal cord ischemia-reperfusion injury was induced in rabbits by infrarenal aortic occlusion for 30 minutes. Two days before the injury was induced, bone marrow stromal cells (1 × 10(8) in 0.2-mL phosphate-buffered saline) were transplanted by intrathecal injection. Hind-limb motor function was assessed using Tarlov criteria, and motor neurons in the ventral gray matter were counted by histologic examination. The permeability of the blood-spinal cord barrier was examined using Evans blue (EB) and lanthanum nitrate as vascular tracers. The expression and localization of tight junction protein occludin were assessed by Western blot, real-time polymerase chain reaction, and immunofluorescence analysis. Matrix metalloproteinase-9 (MMP-9) and tumor necrosis factor-α (TNF-α) expression were also measured.

RESULTS

Intrathecal transplantation of bone marrow stromal cells minimized the neuromotor dysfunction and histopathologic deficits (P < .01) and attenuated EB extravasation at 4 hours (5.41 ± 0.40 vs 7.94 ± 0.36 μg/g; P < .01) and 24 hours (9.03 ± 0.44 vs 15.77 ± 0.89 μg/g; P < .01) after spinal cord ischemia-reperfusion injury. In addition, bone marrow stromal cells treatment suppressed spinal cord ischemia-reperfusion injury-induced decreases in occludin (P < .01). Finally, bone marrow stromal cells reduced the excessive expression of MMP-9 and TNF-α (P < .01).

CONCLUSIONS

Pre-emptive intrathecal transplantation of bone marrow stromal cells stabilized the blood-spinal cord barrier integrity after spinal cord ischemia-reperfusion injury in a rabbit model of transient aortic occlusion. This beneficial effect was partly mediated by inhibition of MMP-9 and TNF-α and represents a potential therapeutic approach to mitigating spinal cord injury after aortic occlusion.

CLINICAL RELEVANCE

Clinical thoracoabdominal aorta surgery may trigger spinal cord ischemia-reperfusion injury, resulting in paraplegia as well as bladder, bowel, and sexual dysfunction. Transplantation of bone marrow stromal cells has attracted increasing attention in the field of nervous system protection, but its mechanisms have not been elucidated completely. The blood-spinal cord barrier plays a crucial role to maintain normal spinal cord function. This study suggested that intrathecal transplantation of bone marrow stromal cells stabilized blood-spinal cord barrier integrity through inhibiting the upregulation of matrix metalloproteinase-9 and tumor necrosis factor-a and ameliorated spinal cord ischemia-reperfusion injury. This may provide a novel train of thought to enhance the protective effects of bone marrow stromal cells on spinal cord injury.

Descending thoracic aortic surgery: update on mortality, morbidity, risk assessment and management

PURPOSE OF REVIEW

The purpose of this review is to summarize the literature on thoracic aortic surgery, as well as key management guidelines in the perioperative period. This is particularly timely, as endovascular techniques continue to evolve and become more available.

RECENT FINDINGS

Endovascular treatment of thoracic aortic disease is expanding in applications and case complexity.

SUMMARY

With the expanded use of endovascular techniques to treat aortic disease, midterm and long-term outcome studies and comparisons to open surgical approach are now being published with increasing frequency. This review analyzes the available literature on preventing adverse outcomes after descending thoracic aortic surgery, with specific attention to mortality, morbidity, risk assessment and management in the perioperative setting.

Distal aortic perfusion during thoracoabdominal aneurysm repair for prevention of paraplegia

BACKGROUND

During thoracoabdominal aortic aneurysm (TAAA) surgery, decreased spinal cord perfusion can result in neurological deficits such as paraplegia and paraparesis. Distal aortic perfusion, alone or in combination with other adjuncts, may counter the decrease in spinal cord perfusion and hence reduce the risk of spinal cord injury.

OBJECTIVES

To determine the effectiveness of distal aortic perfusion with or without other adjuncts against other adjuncts without use of distal perfusion during TAAA surgery in reducing the risk of developing paraplegia and paraparesis.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Specialised Register (last searched 5 January 2012) and CENTRAL (Issue 4, 2011) were searched for publications describing randomised controlled trials of distal aortic perfusion during thoracoabdominal aortic aneurysm surgery. Reference lists of relevant studies were checked.

SELECTION CRITERIA

Randomised or quasi-randomised controlled clinical trials of distal aortic perfusion during TAAA repair.

DATA COLLECTION AND ANALYSIS

Studies identified for potential inclusion were independently assessed for inclusion by at least two authors, with excluded trials arbitrated by the third author.

MAIN RESULTS

There were no randomised controlled trials identified.

AUTHORS' CONCLUSIONS

Currently, there are no randomised controlled trials to support the role of distal aortic perfusion in TAAA surgery for prevention of neurological injury. However, randomised controlled trials are not always feasible based on ethical grounds. Observational studies suggest that distal aortic perfusion alone or in combination with other adjuncts, that is cerebrospinal fluid (CSF) drainage, reduces the rate of neurologic deficit across all types of TAAA; in particular making a striking difference in the rate of neurologic deficit following type II TAAA repair. In the absence of randomised controlled trials, we recommend a standardised approach to reporting through registry studies to strengthen the evidence base for distal aortic perfusion.