Surgical techniques. Thoracoabdominal aorta

Organ Protection During Thoracoabdominal Aortic Surgery: Rationale for a Multimodality Approach

Surgical repair of thoracoabdominal aortic aneurysms (TAAAs) remains a technically challenging operation that requires a systematic approach to prevent ischemic complications and achieve excellent clinical outcomes. Techniques for organ protection have evolved substantially over the past 20 years. This review describes our current multimodality approach to organ protection during TAAA repair.

[Thoracic aorta aneurysm as a complication after transpedicular stabilization of the thoracic vertebral column--a case study]

INTRODUCTION

Incorrectly positioned transpedicular stabilization accounts for 4 to 30% of the complications occurring after vertebral column stabilization operations.

OBSERVATIONS

We describe a specific complication following transpedicular stabilization of TH5-TH7, performed due to fracture of the TH6 vertebra. Given that the patient complained of pain in the thoracic vertebrae, a CT scan of the TH5-TH7 region was performed and revealed that the transpedicular stabilization was incorrectly located; it was immediately adjacent to the thoracic aorta and had led to the formation of a false aneurysm. The stabilization was removed and the patient is under the constant supervision of a vascular surgeon.

CONCLUSIONS

Thoracic aorta false aneurysm is a rare complication after vertebral column stabilization. However, there is a high risk of the aorta wall damage during stabilization removal.

Role of poly(ADP-ribose) polymerase during vascular reconstruction

Open vascular repair of ischemic myocardium and aortic aneurysms results in a systemic inflammatory response that influences the mortality and morbidity of these procedures. Recent studies in animal models of complex vascular reconstruction indicate that the activity of poly(ADP-ribose) polymerase (PARP) may influence the mortality and morbidity of these kinds of reconstructions. PARP's activity, localized to nuclei and mitochondria, is stimulated by deoxyribonucleic acid (DNA) strand breaks. Activation of PARP results in synthesis of poly(ADP-ribose) sugar moieties, whose primary role is to protect DNA from degradation during cytotoxic stress. Paradoxically, when stressful conditions similar to those experienced during vascular reconstructions result in overactivation of PARP, depletion of cellular levels of adenosine triphosphate and nicotinamide adenine dinucleotide can result in exacerbation of tissue injury. Herein we review the role of PARP in inflammation and its relevance to cardiovascular reconstructions.

Strategies for prevention and operative treatment of aortic lesions related to spinal interventions

STUDY DESIGN

A retrospective analysis of a case series was performed.

OBJECTIVE

To give recommendations for the prevention and operative treatment of thoracic and thoracoabdominal aortic lesions in association with spinal interventions.

SUMMARY OF BACKGROUND DATA

Aortic lesions after spinal interventions for traumatic vertebral fractures, segmental spondylodiscitis, or vertebral metastasis are fortunately rare, but associated with a high perioperative mortality rate and absolute numbers are unknown. Therefore, preventive strategies to avoid perioperative major vessel injuries and recommendations for the operative treatment of aortic lesions related to spinal surgery are required.

METHODS

The clinical course of 10 patients with an acute aortic hemorrhage or an increased intraoperative risk for aortic injuries in association with primary or secondary spinal interventions is reported. All patients were evaluated before surgery by orthopedic trauma surgeons, vascular surgeons, and diagnostic radiologists.

RESULTS

Five patients had preventive vascular interventions to avoid major aortic injuries during spinal reinterventions, and 5 patients were treated as an emergency for acute intraoperative hemorrhage related to spinal interventions. The operative treatment was performed by direct aortic sutures (n = 3), segmental alloplastic reconstructions (n = 2), or endovascular stent graft implantations (n = 3). Prophylactic banding of the thoracic aorta during thoracotomy or a femoral access for possible aortic balloon blockade was performed in patients with an estimated lower risk for an aortic laceration caused by malpositioned pedicle screws. No perioperative mortality was observed in patients treated by this interdisciplinary concept, but 1 patient treated under emergency condition for spondylodiscitis with an initially unrecognized aortic lesion died.

CONCLUSION

In patients with complex spinal trauma, spondylodiscitis or difficult vertebral reinterventions, and an increased risk of major vessel injury, a preoperative interdisciplinary evaluation is recommended, even under emergency conditions. Endovascular stent graft technique is an additional option for prevention and treatment of suspected or acute aortic injuries of thoracic and infrarenal aortic lesions, whereas injuries to the visceral aortic segment still require advanced vascular reconstructions.

Delayed Spinal Cord Deficits After Thoracoabdominal Aortic Aneurysm Repair

BACKGROUND

Limited information is available about the treatment and outcomes of delayed paraplegia after thoracoabdominal aortic aneurysm (TAAA) repair. The objective of this study was to assess factors that precipitate and favorably affect delayed-onset neurologic deficits.

METHODS

Over a 19-year period, 2,368 TAAA repairs were performed. Of the 93 patients (3.9%) who had postoperative paraplegia or paraparesis, 34 (37%) initially had intact neurologic function, but a delayed spinal cord deficit developed. We retrospectively examined clinical factors and events associated with development of the deficits, treatments used, and outcomes. Factors related to functional status were evaluated by comparing survivors who were ambulatory at discharge or transfer with those who were not.

RESULTS

The delayed deficits occurred between 13 hours and 91 days postoperatively and were associated with a period of hypotension in 9 patients (26%). Two patients (6%) died in hospital. Of the 32 patients discharged or transferred, 13 (41%) were ambulatory. Poor functional outcomes were associated with female sex, intraoperative cerebrospinal fluid drainage, fewer intercostal arteries reattached, and administration of corticosteroids or osmotic diuretics. The actuarial survival rate at 2 years was 80% +/- 13% for the ambulatory patients and 32% +/- 12% for the nonambulatory patients (p = 0.002).

CONCLUSIONS

Although precipitating episodes of hypoperfusion were common, most cases of delayed paraplegia occurred without such events, suggesting that other factors may play an important role in the development of this complication. Ambulatory status at discharge significantly predicts midterm survival.

Spectrum of Aortic Operations in 300 Patients With Confirmed or Suspected Marfan Syndrome

BACKGROUND

Cardiovascular disease is the main cause of morbidity and mortality in patients with Marfan syndrome. Many patients with presumed Marfan syndrome do not meet current diagnostic criteria. This study reviews the surgical aspects of aortic disease in 300 patients referred with the diagnosis of Marfan syndrome.

METHODS

During a 16-year period, 300 patients with presumed Marfan syndrome underwent 398 operations on the aorta and branch arteries, including 125 aortic root operations, 59 aortic arch repairs, 31 descending thoracic aortic repairs, and 178 thoracoabdominal aortic repairs. Based on medical record review, patients were classified as confirmed Marfan syndrome if documented features satisfied current diagnostic criteria; patients not meeting these criteria were classified as suspected Marfan syndrome.

RESULTS

There were 17 operative deaths (4.3%) after the 398 operations. Survival after the initial referral operation was 96.2% +/- 1.5% at 1 year, 82.7% +/- 2.4% at 5 years, and 74.6% +/- 3.1% at 10 years. Presentations, operative details, and outcomes were remarkably similar in the 137 patients (45.7%) with confirmed Marfan syndrome and the 163 patients (54.3%) with suspected Marfan syndrome. Freedom from repair failure, however, was significantly better in patients with confirmed Marfan syndrome (90.3% +/- 2.3% at 10 years) than in those with suspected Marfan syndrome (82.0% +/- 3.1% at 10 years; p = 0.001).

CONCLUSIONS

Operative treatment of the full spectrum of aortic disease in Marfan patients enables excellent long-term survival. Similarities in surgical aspects of aortic disease suggest that patients with features of Marfan syndrome who do not meet diagnostic criteria should be managed in the same manner as patients with confirmed Marfan syndrome.

Existence of abdominal aortic aneurysms in patients with thoracic aortic dissections

OBJECTIVE

The objective of this study was to determine the coexistence or later development of pararenal and infrarenal abdominal aortic aneurysms (AAAs) in patients with thoracic aortic dissections.

METHODS

One hundred forty-five patients (95 men, 50 women) encountered from 1992 to 2001 with thoracic aortic dissections-excluding those associated with trauma, those with Marfan's syndrome, and those with thoracoabdominal aortic aneurysms-were studied. The most common risk factors included hypertension (59%) and a history of tobacco use (52%). Type III dissections affected 86 patients (59%), and type I dissections affected the remaining 59 patients (41%). Aortic computed tomography (CT) scans were obtained annually. Data were assessed by univariate and multivariate analyses.

RESULTS

Five patients (3%) had a history of AAA repair prior to their thoracic aortic dissection diagnosis-3 were type III dissections and 2 were type I dissections. Twelve patient's (8%) AAAs were diagnosed with the initial CT study of their thoracic aortic dissection. Type III dissections accounted for all but one of these (11 of 12, 92%). Ten additional AAAs (7%) developed in the 128 patients with no initial evidence of an AAA being recognized from 1 to 48 months (average 16 months) after the thoracic aortic dissection was diagnosed. Type III dissections affected 8 of these 10 patients. Among the total 27 AAAs noted in this series, 74% (20 AAAs) were not continuous with the thoracic aortic dissection. In the univariate analysis, age (P =.0002), male gender (P =.044), history of smoking (P =.01), chronic obstructive pulmonary disease (P <.001), duration of dissection (P =.05), and presence of type III dissection (P =.009) were associated with the presence of an AAA. In the multivariate analysis, both chronic obstructive pulmonary disease (odds ratio 5.4, 95% CI, 1.3 to 22.3; P =.02) and age (OR 1.06, 95% CI, 1.02 to 1.11; P =.004) were significant predictors of the development of AAAs.

CONCLUSION

This study documented that patients with thoracic aortic dissections are at risk to harbor or develop a later AAA. This finding supports the tenet that abdominal CTs or ultrasound scanning should be mandatory in the follow-up of patients with known thoracic aortic dissections.

Estimating group mortality and paraplegia rates after thoracoabdominal aortic aneurysm repair

BACKGROUND

Most clinical studies regarding thoracoabdominal aortic aneurysm (TAAA) surgery are retrospective comparisons involving heterogeneous groups of patients. Risk models that evaluate susceptibility bias enhance interpretation of these intergroup comparisons. The purpose of this analysis was to derive group risk models for mortality and paraplegia after TAAA repair.

METHODS

Data regarding 1,220 consecutive patients undergoing TAAA repair were analyzed via multiple logistic regression with stepwise model selection. Categorical preoperative risk factors that predicted 30-day mortality and paraplegia were used to develop risk models.

RESULTS

Fifty-eight patients (4.8%) died within 30 days and 56 patients (4.6%) developed paraplegia or paraparesis. Predictors of mortality were rupture, renal insufficiency, symptomatic aneurysms, and Crawford extent II repairs. Extent of repair and acute presentation were predictors of paraplegia. The derived risk models estimated mortality and paraplegia rates that correlated well with actual frequencies reported in other contemporary series (regression slopes = 0.87 and 1.06, respectively).

CONCLUSIONS

The derived risk models accurately estimate paraplegia and mortality rates in groups of patients. Prospective model validation will be required to confirm their accuracy.

Thoracoabdominal aortic aneurysm repair: review and update of current strategies

BACKGROUND

Surgical repair of thoracoabdominal aortic aneurysms remains a technically challenging operation that requires a multimodality approach to preventing ischemic complications. The purpose of this report is to update our experience and highlight our current clinical strategies.

METHODS

Between January 1, 1986 and December 31, 2001, 1,773 patients underwent thoracoabdominal aortic aneurysm repair. The majority of these patients (1,153, 65%) required Crawford extent I or II repairs. Segmental intercostal or lumbar arteries were reattached in 1,082 patients (61%); left heart bypass was used in 686 patients (38.7%), and 173 patients (9.8%) had cerebrospinal fluid drainage.

RESULTS

The 30-day survival rate was 94.3% (1,672 patients). Postoperative complications included renal failure requiring hemodialysis in 105 patients (5.9%) and paraplegia or paraparesis in 79 patients (4.5%). Actuarial 5-year survival was 73.5% +/- 1.6%.

CONCLUSIONS

This clinical experience demonstrates that current technical strategies enable patients to undergo thoracoabdominal aortic aneurysm repair with excellent early survival and acceptable morbidity.

Emergency surgery for thoracoabdominal aortic aneurysms with acute presentation

PURPOSE

The mortality rate for elective repair of thoracoabdominal aortic aneurysms is as low as 4% in some surgical centers. However, patients with emergent presentation with acute pain, rupture, or complicated acute dissection traditionally have a poor outcome. We evaluated the results of surgery in a large contemporary series of patients with acute presentation at a tertiary referral center with a special interest and experience in aortic surgery.

METHODS

Between 1986 and 1998, 1220 patients underwent repair of thoracoabdominal aortic aneurysms. One hundred twelve patients had acute presentation, and 1108 patients underwent elective repair. Data were collected in a prospectively generated database.

RESULTS

Seventy-six patients had rupture, and 36 patients had acute dissection without rupture. The operative mortality rate was 6% for elective cases and 17% for acute cases (P =.0004). The long-term survival was longer for the elective group compared with the acute group (mean, 8.3 +/- 0.4 years versus 5.5 +/- 0.7 years; P <.005). Age did not influence survival rate in the acute group. Postoperative pulmonary complications, paraplegia/paraparesis, and renal impairment occurred in 45%, 14%, and 25%, respectively, of acute cases and were significantly more common than in elective cases (P < or =.01). Left heart bypass was used in 34 acute patients (30%), and intercostal arteries were reattached in 66 acute patients (59%). Surgery without the use of either adjunct was associated with significantly higher mortality and renal impairment rates.

CONCLUSION

Repair of thoracoabdominal aortic aneurysms with acute presentation is associated with worse outcome compared with elective cases. Nevertheless, repair may be performed with reasonable mortality and morbidity rates at specialized centers. In the acute setting, the use of surgical adjuncts is associated with improved outcome and should be used when possible. Age does not impact on survival rate in patients with acute presentation, and surgery should not be restricted to only younger patients.

Morbidity and mortality after extent II thoracoabdominal aortic aneurysm repair

BACKGROUND

Surgical repair of Crawford extent II thoracoabdominal aortic aneurysms (TAAAs) carries substantial risk for morbidity and mortality. The purpose of this study was to analyze the results of a large consecutive series of extent II TAAA repairs and identify factors that influence morbidity and survival.

METHODS

Of 1,415 consecutive patients who underwent TAAA operations over a 13-year period, 442 (31.2%) had extent II repairs. Data from a prospectively maintained database were analyzed to determine which factors were associated with death and major complications.

RESULTS

The operative mortality was 10.0% (44 patients). Postoperative complications included paraplegia/paraparesis in 33 patients (7.5%), pulmonary complications in 158 (35.7%), and renal failure in 69 (15.9%). Multivariable analysis revealed that renal insufficiency (odds ratio [OR] 2.6), increasing age (OR 1.1/year), and increasing red blood cell transfusion requirements (OR 1.1/U) were predictors for mortality; renal insufficiency (OR 2.8) and peptic ulcer disease (OR 9.3) were predictors of renal failure; and rupture (OR 6.3) was a predictor of paraplegia. Left heart bypass was an independent protective factor against paraplegia (OR 0.4).

CONCLUSIONS

This contemporary experience demonstrates acceptable levels of morbidity and mortality in this high-risk group. Left heart bypass was found to provide protection against paraplegia in these patients.

Cerebrospinal fluid drainage reduces paraplegia after thoracoabdominal aortic aneurysm repair: results of a randomized clinical trial

OBJECTIVE

Despite the use of various strategies for the prevention of spinal cord ischemia, paraplegia and paraparesis continue to occur after thoracoabdominal aortic aneurysm (TAAA) repair. Although cerebrospinal fluid drainage (CSFD) is often used as an adjunct for spinal cord protection, its benefit remains unproven. The purpose of this randomized clinical trial was to evaluate the impact of CSFD on the incidence of spinal cord injury after extensive TAAA repair.

METHODS

After randomization, 145 patients underwent extent I or II TAAA repairs with a consistent strategy of moderate heparinization, permissive mild hypothermia, left heart bypass, and reattachment of patent critical intercostal arteries. The repairs were performed with CSFD (n = 76) or without CSFD (n = 69). In the former group, CSFD was initiated during the operation and continued for 48 hours after surgery. The target CSF pressure was 10 mm Hg or less.

RESULTS

The two groups had similar risk factors for paraplegia. Aortic clamp time, left heart bypass time, and number of reattached intercostal arteries were also similar in both groups. Thirty-day mortality rates were 5.3% (four patients) and 2.9% (two patients) for CSFD and control groups, respectively (P =.68). Nine patients (13.0%) in the control group had paraplegia or paraparesis develop. In contrast, only two patients in the CSFD group (2.6%) had deficits develop (P =.03). No patients with CSFD had immediate paraplegia. Overall, CSFD resulted in an 80% reduction in the relative risk of postoperative deficits.

CONCLUSION

Perioperative CSFD reduces the rate of paraplegia after repair of extent I and II TAAAs.

The outcome in the United States after thoracoabdominal aortic aneurysm repair, renal artery bypass, and mesenteric revascularization

OBJECTIVES

The purpose of this study was to determine outcome and identify predictors of death after thoracoabdominal aortic aneurysm (TAA) repair, renal artery bypass (RAB), and revascularization for chronic mesenteric ischemia (CMI).

PATIENTS AND METHODS

In this retrospective analysis, data were obtained from the Nationwide Inpatient Sample, a 20% all-payer stratified sample of hospitals in the United States during 1993 to 1997. Patients were identified by the presence of a diagnostic or procedure code from the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). The main outcomes we examined were death, ICD-9-CM -based complications, length of stay, hospital charges, and disposition. A multivariate model was constructed to predict death.

RESULTS

A total of 2934 patients were identified (TAA, 540; RAB, 2058; CMI, 336) in the database. The mean age was comparable (TAA, 69 +/- 9 years; RAB, 66 +/- 12 years; CMI, 66 +/- 11 years), but the breakdown between the sexes varied by procedure (male: TAA, 53%; RAB, 55%; CMI, 24%). The mortality rate (TAA, 20.3%; RAB, 7.1%; CMI, 14.7%), complication rate (TAA, 62.2%; RAB, 37.4%; CMI, 44.6%), and the percentage of patients discharged to another institution (TAA, 21.2%; RAB, 9.3%; CMI, 12.0%) were clinically significant for all procedures. The mortality rate for RAB was greater when performed concomitant with an aortic reconstruction (4.4% vs 8.3%). All three procedures were resource intensive as reflected by the median length of stay (TAA, 14 days; RAB, 9 days; CMI, 14 days) and median hospital charges (TAA, $64,493; RAB, $36,830; CMI, $47,390). The multivariate model identified several variables for each procedure that had an impact on the predicted mortality rate (TAA, 14%-76%; RAB, < 1%-46%; CMI, < 2%-87%).

CONCLUSIONS

The operative mortality rates across the United States for patients undergoing TAA repair and RAB are greater than commonly reported in the literature and mandate reexamining the treatment strategies for these complex vascular problems.

A new predictive model for adverse outcomes after elective thoracoabdominal aortic aneurysm repair

BACKGROUND

Recent recommendations have emphasized individualized treatment based on balancing a patient's risk of thoracoabdominal aortic aneurysm rupture with the risk of an adverse outcome after surgical repair. The purpose of this study was to determine which preoperative risk factors currently predict an adverse outcome after elective thoracoabdominal aortic aneurysm repair.

METHODS

A single, composite end point termed adverse outcome was defined as the occurrence of any of the following: death within 30 days, death before discharge from the hospital, paraplegia, paraparesis, stroke, or acute renal failure requiring dialysis. A risk factor analysis was performed using data from 1,108 consecutive elective thoracoabdominal aortic aneurysm repairs.

RESULTS

The incidence of an adverse outcome was 13.0% (144 of 1,108 patients); predictors included preoperative renal insufficiency (p = 0.0001), increasing age (p = 0.0035), symptomatic aneurysms (p = 0.020), and extent II aneurysms (p = 0.0001). These risk factors were used to construct an equation that estimates the probability of an adverse outcome for an individual patient.

CONCLUSIONS

This new predictive model may assist in decisions regarding elective thoracoabdominal aortic aneurysm operations. For patients who are acceptable candidates, contemporary surgical management provides favorable results.