Use of left heart bypass in the surgical repair of thoracoabdominal aortic aneurysms

Outcomes following Management of Complex Thoracoabdominal Aneurysm by an Open Approach

BACKGROUND

In the last decade, advances in surgical techniques, and the introduction of adjuncts for organ protection, have modified the approach for thoracoabdominal aortic aneurysm (TAAA) surgical repair. The aim of this study is to determine whether the contemporary approach influenced the outcomes.

METHODS

From 1989 to 2022, patients who had received elective open surgical repair (OSR) for TAAA at our institution were retrospectively analyzed. This series has been divided in two groups: Group 1 (1989-2009), and Group 2 (2010-2022). Patients included in Group 1 were those treated with a selective use of adjuncts, and Group 2 included patients treated with the systematic use of adjuncts.

RESULTS

A total of 1107 patients were treated (Group 1: 455; Group 2: 652). The surgical management was significantly different between the two groups. The in-hospital mortality was significantly different between the two groups (Group 1: 13.4%, Group 2: 8.1%; p 0.004), as was the rate of permanent spinal cord ischemia (Group 1: 11.9%, Group 2: 7.8%; p 0.023). Renal and respiratory failure were reduced in Group 2, but not significantly.

CONCLUSIONS

The use of the adjuncts enabled the achievement of improvement in mortality and SCI prevention in TAAA OSR. Although a refined surgical technique, mortality and morbidity are still noteworthy in this complex aortic field.

Open Replacement of the Thoracoabdominal Aorta: Short- and Long-term Outcomes at a Single Institution

Background  Despite much progress in the surgical and endovascular treatment of thoracoabdominal aortic diseases (TAADs), there is no consensus regarding the optimal approach to minimize operative mortality and end-organ dysfunction. We report our experience in the past 16 years treating TAAD by open surgery. Methods  A retrospective review of all TAAD patients who underwent an open repair since January 2000 was performed. The primary endpoints included early morbidity and mortality, and the secondary endpoints were overall death and rate of aortic reintervention. Results  There were 112 patients treated by open surgery for TAAD. Mean age was 66 ± 10 years and 61 (54%) were male. Seventy-seven (69%) patients had aneurysmal degeneration without aortic dissection and the remaining 35 (31%) had a concomitant aortic dissection. There were 12 deaths (10.7%) and they were equally distributed between the aneurysm and dissection groups ( p  = 0.8). The mortality for elective surgery was 3.2% (2/61). The rate of permanent paraplegia and stroke were each 2.6% (3/112). The rate of cerebrovascular accident was significantly higher in the dissection group (8.5% vs. 1.2%, p  = 0.05). The survival at 1, 5, and 10 years was 80.6, 56.1, and 32.7%, respectively. Conclusion  Our data confirm that open replacement of the thoracoabdominal aorta can be performed in expert centers quite safely. Different aortic pathologies (degenerative aneurysm vs. dissection) do not influence the short- and long-term outcomes. Open surgery should still be considered the standard in the management of TAAD.

Bypass Techniques for Descending Thoracic Aortic Surgery

The conduct of partial left heart bypass or partial car diopulmonary bypass (CPB) during surgery involving the descending thoracic aorta or thoracoabdominal aorta is one of the most unappreciated and misunder stood extracorporeal circulation procedures in cardio vascular surgery. It is different from conventional CPB, and although some uninitiated practitioners consider it simpler, it is in fact more complicated than conven tional CPB and involves different concepts. It requires expertise and skill in regulating the flow, pressure, and oxygenation of blood going to both the proximal and distal parts of the body and management of the special bypass or shunt procedures used, specialized monitor ing, and knowledge about the protection and preserva tion of organs both proximal and distal to the aortic clamping. It demands exquisite communication and un derstanding of the unique problems faced by the sur geon, anesthesiologist, and perfusionist.

Repair of adult aortic coarctation by resection and interposition grafting

OBJECTIVES

Aortic coarctation presenting during adult life most frequently represents cases of re-coarctation, following previous transcatheter or surgical therapy, or missed cases of native coarctation. In the area of evolving endovascular therapy, we believe that there is still a place for durable open repair by means of resection and interposition grafting. We, therefore, evaluated our results in adult patients with primary aortic coarctation or complications of a previous coarctation repair.

METHODS

A total of 38 patients were operated between 1989 and 2014. Median age was 43 years (range 18-69 years), and 20 were male (52.6%). Seventeen patients (44.7%) had recurrent coarctation or dilatation after previous repair during childhood; the remaining 21 (55.3%) had primary coarctation diagnosed at adult age. Data were retrospectively reviewed and analysed for indications, type of repair, operative details and outcomes.

RESULTS

Resection and interposition grafting was performed primarily with the use of left-left bypass (mean cross-clamping time 41 ± 13 min). There were no in-hospital deaths, stroke, spinal cord ischaemia, renal or respiratory failure. No patient had evidence of symptomatic aortic re-coarctation or pseudoaneurysm formation on follow-up. Long-term survival after 20 years was 94.7%.

CONCLUSIONS

Open surgical repair of primary, recurrent or complicated adult aortic coarctation by interposition grafting is a safe and feasible therapeutic option, providing durable long-term results and excellent long-term survival.

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.

Cerebrospinal fluid drainage for thoracic and thoracoabdominal aortic aneurysm surgery

BACKGROUND

During aortic aneurysm surgery, cross-clamping can lead to inadequate blood supply to the spinal cord resulting in neurological deficit. Cerebrospinal fluid drainage (CSFD) may increase the perfusion pressure to the spinal cord and hence reduce the risk of ischaemic spinal cord injury.

OBJECTIVES

To determine the effect of CSFD during thoracic and thoracoabdominal aortic aneurysm (TAAA) surgery on the risk of developing spinal cord injury.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched May 31 2012) and CENTRAL (2012, Issue 5) for publications describing randomised controlled trials of cerebrospinal fluid drainage for thoracic and thoracoabdominal aortic aneurysm surgery. Reference lists of relevant articles were checked.

SELECTION CRITERIA

Randomised trials involving CSFD during thoracic and TAAA surgery.

DATA COLLECTION AND ANALYSIS

Both authors assessed the quality of trials independently. SNK extracted data and GS verified the data.

MAIN RESULTS

Three trials with a total of 287 participants operated on for Type I or II TAAA were included.In the first trial of 98 participants, neurological deficits in the lower extremities occurred in 14 (30%) of CSFD group and 17 (33%) controls. The deficit was observed within 24 hours of the operation in 21 (68%), and from three to 22 days in 10 (32%) participants. CSFD did not have a significant benefit in preventing ischaemic injury to the spinal cord.The second trial of 33 participants used a combination of CSFD and intrathecal papaverine. It showed a statistically significant reduction in the rate of postoperative neurological deficit (P = 0.039), compared to controls. Analysis was undertaken after only one third of the estimated sample size had entered the trial.In the third trial TAAA repair was performed on 145 participants. CSFD was initiated during the operation and continued for 48 hours after surgery. Paraplegia or paraparesis occurred in 9 of 74 participants (12.2%) in the control group versus 2 of 82 participants (2.7%) receiving CSFD (P = 0.03). Overall, CSFD resulted in an 80% reduction in the relative risk of postoperative deficits. Meta-analysis showed an odds ratio (OR) of 0.48 (95 % confidence interval (CI) 0.25 to 0.92). For CSFD-only trials, OR was 0.57 (95% CI 0.28 to 1.17) and for intention-to-treat analysis in CSFD-only studies, the OR remained unchanged.

AUTHORS' CONCLUSIONS

There are limited data supporting the role of CSFD in thoracic and thoracoabdominal aneurysm surgery for prevention of neurological injury. Further clinical and experimental studies are indicated.

Blood supply and vascular reactivity of the spinal cord under normal and pathological conditions

The authors present a review of spinal cord blood supply, discussing the anatomy of the vascular system and physiological aspects of blood flow regulation in normal and injured spinal cords. Unique anatomical functional properties of vessels and blood supply determine the susceptibility of the spinal cord to damage, especially ischemia. Spinal cord injury (SCI), for example, complicating thoracoabdominal aortic aneurysm repair is associated with ischemic trauma. The rate of this devastating complication has been decreased significantly by instituting physiological methods of protection. Traumatic SCI causes complex changes in spinal cord blood flow, which are closely related to the severity of injury. Manipulating physiological parameters such as mean arterial blood pressure and intrathecal pressure may be beneficial for patients with an SCI. Studying the physiopathological processes of the spinal cord under vascular compromise remains challenging because of its central role in almost all of the body's hemodynamic and neurofunctional processes.

Repair of extensive thoracoabdominal aortic aneurysm with a tetrafurcate graft: midterm results of 63 cases

OBJECTIVE

The objective is to present a method for maintaining the spinal cord blood supply and our midterm results for using a tetrafurcate graft in extensive thoracoabdominal aortic aneurysm (TAAA) repair.

METHODS

From August 2003 to October 2007, we used a tetrafurcate graft to perform repairs to TAAAs of Crawford extent II in 63 consecutive patients. The mean age of this group of patients was 39.98 +/- 10.62 years, and 46 (73%) of them were male. All of the procedures were performed under profound hypothermia with a short interval of circulatory arrest. T6 to T12 intercostal arteries were reconstructed as a "neo-intercostal artery" (N-IA) and were connected to an 8-mm sidearm of the graft to maintain the spinal cord blood supply. Visceral arteries were joined into a patch and were anastomosed to the end of the main graft. The left renal artery was anastomosed to an 8-mm sidearm or joined to the patch. The other 10-mm sidearms were anastomosed to iliac arteries.

RESULTS

With 100% follow-up, the early-mortality rate was 7.94%. The incidence of cerebral complications was 9.52%. Temporary paraplegia was observed in 2 patients, and paraparesis occurred in 1 patient. Pulmonary complication was the most common morbidity in this group (25.40%). Two patients with Marfan syndrome had N-IA artery pseudoaneurysms during follow-up. The mean survival time of this group was 50.64 +/- 2.13 months, with survival rates of 92.06% after 1 year, 88.38% after 2 years, and 86.11% after 3 years.

CONCLUSION

The N-IA may play an important role in spinal cord protection, and N-IA pseudoaneurysm should be avoided in Marfan syndrome patients. The use of a tetrafurcate graft is a reliable method for TAAA repair, with satisfactory midterm results.

Cerebrospinal fluid drainage for thoracic and thoracoabdominal aortic aneurysm surgery

BACKGROUND

During aortic aneurysm surgery, cross-clamping can lead to inadequate blood supply to the spinal cord resulting in neurological deficit. Cerebrospinal fluid drainage (CSFD) may increase the perfusion pressure to the spinal cord and hence reduce the risk of ischaemic spinal cord injury.

OBJECTIVES

To determine the effect of CSFD during thoracic and thoracoabdominal aortic aneurysm (TAAA) surgery on the risk of developing spinal cord injury.

SEARCH STRATEGY

The reviewers searched the Cochrane Peripheral Vascular Diseases Group Specialised Trials Register (last searched October 2003), the Cochrane Central Register of Controlled Trials (CENTRAL) database (last searched Issue 4, 2003), MEDLINE and EMBASE, and reference lists of relevant articles. Recent conference proceedings were scanned.

SELECTION CRITERIA

Randomised trials involving CSFD during thoracic and TAAA surgery.

DATA COLLECTION AND ANALYSIS

Both reviewers assessed the quality of trials independently. One reviewer (SNK) extracted data and the other reviewer (GS) verified the data.

MAIN RESULTS

Three trials, with a total of 287 participants operated on for type I or II TAAA, were included. In the first trial of 98 patients, neurological deficits in the lower extremities occurred in 14 (30%) CSFD and 17 (33%) controls. The deficit was observed within 24 hours of the operation in 21 (68%), and from 3 to 22 days in 10 (32%). CSFD did not have a significant benefit in preventing ischaemic injury to the spinal cord. The second trial of 33 patients used a combination of CSFD and intrathecal papaverine. It showed a statistically significant reduction in the rate of postoperative neurological deficit (p = 0.039), compared to controls. Analysis was undertaken after only one third of the estimated sample size had entered the trial. In the third trial TAAA repair was performed on 145 patients. CSFD was initiated during the operation and continued for 48 hours after surgery. Paraplegia or paraparesis occurred in 9 of 74 patients (12.2%) in the control group versus 2 of 82 patients (2.7%) with CSFD (p = 0.03). Overall, CSFD resulted in an 80% reduction in the relative risk of postoperative deficits. Meta-analysis showed an odds ratio (OR) of 0.48 (0.25 to 0.92; confidence interval (CI) 95%). For CSFD trials only OR was 0.57 (0.28 to 1.17) and for intention-to-treat in CSFD only studies OR remained unchanged.

REVIEWER'S CONCLUSIONS

There are limited data supporting the role of CSFD in thoracic and thoracoabdominal aneurysm surgery for prevention of neurological injury. Further clinical and experimental studies are indicated.

Distal aortic perfusion and cerebrospinal fluid drainage for thoracoabdominal and descending thoracic aortic repair: ten years of organ protection

OBJECTIVE

To report the long-term results of our experience using cerebrospinal fluid drainage and distal aortic perfusion in descending thoracic and thoracoabdominal aortic repair.

SUMMARY BACKGROUND DATA

Repair of thoracoabdominal and thoracic aortic aneurysm by the traditional clamp-and-go technique results in a massive ischemic insult to several major organ systems. Ten years ago, we began to use distal aortic perfusion and cerebrospinal fluid drainage (adjunct) to reduce end-organ ischemia.

METHODS

Between January 1991 and February 2003, we performed 1004 thoracoabdominal or descending thoracic repairs. Adjunct was used in 741 (74%) of 1004. Multivariable data were analyzed by Cox regression. Number needed to treat was calculated as the reciprocal of the risk difference.

RESULTS

Immediate neurologic deficit was 18 (2.4%) of 741 with adjunct and 18 (6.8%) of 263 without (P < 0.0009). In high-risk extent II aneurysms, the numbers were 11 (6.6%) of 167 with adjunct, and 11 (29%) of 38 without. Long-term survival was improved with adjunct (P < 0.002). The long-term survival results persisted after adjustment for age, extent II aneurysm, and preoperative renal function.

CONCLUSION

Use of adjunct over a long period of time has produced favorable results; approximately 1 neurologic deficit saved for every 20 uses of adjunct overall. In extent II aneurysms, where the effect is greatest, this increases to 1 saved per 5 uses. Adjunct is also associated with long-term survival, which is consistent with mitigation of ischemic end-organ injury. These long-term results indicate that cerebrospinal fluid drainage and distal aortic perfusion are safe and effective adjunct for reducing morbidity and mortality following thoracic and thoracoabdominal aortic repair.

The use of left heart bypass in the repair of thoracoabdominal aortic aneurysms: current techniques and results

The surgical repair of thoracoabdominal aortic aneurysms (TAAA) remains challenging. The prevention of spinal cord ischemic complications requires a multidisciplinary approach. The protective effect of left heart bypass (LHB), particularly regarding spinal cord ischemia, during the repair of extensive TAAA is evaluated here. Data from 1,250 consecutive patients who underwent the repair of extent I or extent II TAAA over a 16-year period was prospectively entered into a database. LHB was used in 666 (53.3%) patients. This group was retrospectively compared with 584 (46.7%) patients who had undergone surgery without the use of LHB. A total of 1,173 (93.8%) patients were 30-day survivors. Paraplegia or paraparesis developed postoperatively in 68 (5.5%) patients. In patients with extent I TAAA, paraplegia and paraparesis rates in the LHB cohort (9 of 290, 3.1%) and those without LHB (13 of 313, 4.2%) were statistically similar (P=0.866). The latter was observed despite the fact that longer clamp times were used in the LHB group. In patients with extent II TAAA, the LHB group had a statistically significant lower incidence of paraplegia or paraparesis (17 of 375, 4.5%) compared with the non-LHB group (29 of 259, 11.2%; P=0.019). In our experience, we identified LHB as protective for reducing the risk of postoperative paraplegia and paraparesis in patients who underwent the repair of extent I and extent II TAAA, the latter statistically significant.

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.

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.

Chronic aortic dissection not a risk factor for neurologic deficit in thoracoabdominal aortic aneurysm repair

OBJECTIVE

chronic aortic dissection has long been considered a risk factor for neurologic deficit following thoracoabdominal aortic aneurysm (TAA) surgery. We reviewed our experience with regard to aneurysm extent and the use of adjunct, (distal aortic perfusion/cerebrospinal fluid drainage), and examined the impact of these factors on neurologic deficit among chronic dissection and non-dissection cases.

METHODS

between February 1991 and March 2001, we repaired 800 aneurysms of the descending thoracic and thoracoabdominal aorta. Seven hundred and twenty-nine cases were elective; 196 chronic dissection, 533 non-dissection. 182/729 (24.9%) were TAA extent II. Among these, 61/182 (33%) involved chronic dissection. Adjunct was used in 507/729 (69.6%). We conducted detailed multivariate analyses to isolate the impact of chronic aortic dissection on neurologic morbidity, with other important risk factors taken into account.

RESULTS

overall, 32/729 (4.4%) patients had neurologic deficit upon awakening; 7/196 (3.6%) in chronic dissections, and 25/533 (4.7%) in non-dissections. Adjunct had a major effect, reducing neurologic deficit in TAA extent II from 10/36 (27.8%) to 10/146 (6.9%) (p=0.001). However, in univariate and multivariate analysis, chronic dissection did not increase the risk of neurologic deficit, regardless of extent or mode of treatment.

CONCLUSION

in contrast to previous reports, we determined that chronic aortic dissection is not a risk factor in TAA patients.

Surgical repair of aneurysms involving the suprarenal, visceral, and lower thoracic aortic segments: early results and late outcome

OBJECTIVE

The purpose of this study is to review our experience with surgical repair of lower thoracoabdominal and suprarenal aortic aneurysms to determine early and late survival rates and identify factors influencing morbidity and survival among these patients.

MATERIALS

From 1989 through 1998, 165 consecutive patients underwent repair of 108 thoracoabdominal (55 group III and 53 group IV) and 57 suprarenal aneurysms. The study group consisted of 109 men and 56 women with a mean age of 70 years (median, 70 years; range, 29-89 years). Mean aneurysm diameter was 6.9 cm (median, 6.5 cm; range, 4-12 cm). There were 125 aneurysms (76%) repaired electively; 40 repairs (24%) were nonelective. The cause of 12 aneurysms (7%) was chronic aortic dissection; the remaining 153 (93%) were degenerative aneurysms.

RESULTS

The early postoperative (30-day) mortality rates were 7% (9/125) for elective and 23% (9/40) for nonelective operations (P =.016). For both elective and urgent procedures, early mortality was 1.8% (1/57) for suprarenal aneurysm repair, 11% (6/53) for group IV thoracoabdominal aneurysms, and 20% (11/55) for group III thoracoabdominal aneurysms (P =.013, suprarenal vs group III). Spinal cord ischemia occurred after 6% (10/165) of aneurysm repairs (4% paraplegia, 2% paraparesis). None of the 57 suprarenal aneurysm repairs were complicated by spinal cord ischemia, whereas it occurred in 2% (1/53) of group IV thoracoabdominal aneurysms and 16% (9/55) of group III thoracoabdominal aneurysms (P =.001, suprarenal vs group III; P =. 016, group IV vs group III). Three (25%) of the 12 patients with dissection developed spinal cord ischemia; this compared with seven (5%) of 153 patients with degenerative aneurysms (P =.027). The cumulative 3-year survival rate for the entire series was 71% (95% CI, 64%-79%), and 5-year survival was 50% (95% CI, 40%-60%).

CONCLUSIONS

Aneurysms involving the suprarenal, visceral, and lower thoracic aorta may be repaired with acceptable perioperative mortality and late survival rates. The risk of spinal cord ischemia is increased for patients with aortic dissection and may be stratified according to the proximal extent of the aneurysm.

Comparison of Nikkiso and Bio-Medicus Pumps in Thoracoabdominal Aortic Surgery

Left heart bypass reduces the risk of ischemic complications during the repair of extensive thoracoabdominal aortic aneurysms. This prospective study compared the performance of the recently developed Nikkiso centrifugal pump with the well-established Bio-Medicus pump during left heart bypass for thoracoabdominal aortic aneurysm surgery. Thirty-five consecutive patients undergoing graft repair of extensive thoracoabdominal aortic aneurysms were prospectively assigned to have left heart bypass using either the Bio-Medicus (in the first 19 patients) or Nikkiso pump (in the next 16 patients). There were no significant differences in pump flow rates or patient hemodynamics between the two groups and there was no evidence of pump malfunction. All patients survived and none developed postoperative coagulopathy, myocardial infarction, or left heart failure. Paraparesis developed in 2 patients in the Nikkiso group (12.5%); there were no neurologic complications in the Bio-Medicus group (p = 0.202). One patient in the Bio-Medicus group developed renal failure (5.3%; p = 1.000 vs. Nikkiso group). Overall, no significant differences were found in the incidence of postoperative complications. Although a small series, this comparison demonstrates that the Nikkiso centrifugal pump is as effective and safe in providing left heart bypass during thoracoabdominal aortic aneurysm repair as the widely-used Bio-Medicus model.

Surgical techniques. Thoracoabdominal aorta

Patients presenting with impending rupture of a thoracoabdominal aortic aneurysm require emergency operative repair. To prevent rupture and its associated mortality, elective repair of thoracoabdominal aortic aneurysms exceeding 5.5 cm to 6.0 cm in diameter is recommended in patients with adequate physiologic reserve. Similarly, surgery should be considered for patients with smaller symptomatic aneurysms. Atypical symptoms have been associated with rupture, therefore, they require thorough evaluation. Whether the aortic conditions are caused by medial degenerative disease or chronic aortic dissection, surgical techniques allow for graft repair of thoracoabdominal aortic aneurysms with low mortality and morbidity rates. Although surgery is usually avoided in patients with acute distal aortic dissection, operative intervention is occasionally required when complications develop. Patients with acute aortic dissection complicated by impending rupture of the thoracoabdominal segment require graft repair to restore aortic integrity; although the mortality rate is acceptable, the incidence of postoperative paraplegia approaches 20% in this setting. For patients presenting with ischemic complications of acute distal aortic dissection, less-extensive surgical options have been effective in restoring perfusion. In experienced centers, overall operative survival rate following thoracoabdominal aortic surgery can exceed 92%. Retrospective data suggest that left heart bypass reduces the incidence of paraplegia following extensive thoracoabdominal aortic repairs. Although recent advances have led to improved outcomes, paraplegia continues to occur regardless of the strategy used. The prevention of spinal cord ischemia during thoracoabdominal aortic surgery, therefore, will remain a focus of controversy and investigation, just as it was more than 4 decades ago.

Emergency thoracoabdominal aortic aneurysm repair: clinical outcome

OBJECTIVE

Emergency repair of thoracoabdominal aortic aneurysm remains a formidable operation with high morbidity and mortality. Although advanced surgical and perioperative care techniques have reduced the risks in elective repair of these aneurysms, the mortality rate has remained high when emergency surgery is performed. We have evaluated the outcome of patients undergoing emergency repair of thoracoabdominal aortic aneurysm.

METHODS

Of 47 consecutive patients with thoracoabdominal aortic aneurysm observed from January 1993 to September 1998, 19 required an emergency operation. Twelve had a ruptured aneurysm and 7 an acute dissection. Twelve type I, 3 type II, 1 type III, and 3 type IV thoracoabdominal aortic aneurysms (Crawford's classification) were diagnosed. All patients were operated on via a thoracolaparotomy with partial femoral-femoral extracorporeal circulation. The cerebrospinal fluid pressure was monitored, and the aorta was replaced with a vascular graft. Patent intercostal arteries were reimplanted when feasible.

RESULTS

The early (30-day) mortality was 42.1%; there were 2 late deaths. Complications in the 11 surviving patients are summarized as follows: paraplegia/paraparesis, 3 cases; renal, 4 cases; pulmonary, 4 cases; cardiac, 1 case; cerebrovascular, 1 case; and reexploration for bleeding, 1 case. Hemodialysis and aortic dissection were predictive factors of hospital mortality.

CONCLUSIONS

Our surgical experience in emergency repair of thoracoabdominal aortic aneurysm must be considered encouraging in terms of late outcome despite the in-hospital mortality of 42.1% and serious postoperative complications in the surviving patients. Moreover, our results show that acute aortic dissection and the need for hemodialysis are predictive factors for mortality.

Impact of left heart bypass on the results of thoracoabdominal aortic aneurysm repair

BACKGROUND

This study evaluated the role of left heart bypass on the results of thoracoabdominal aortic aneurysm (TAAA) operations.

METHODS

Two hundred fifty-eight patients had surgical repair of a thoracoabdominal aortic aneurysm between 1981 and 1998 using the inlay technique. Simple cross-clamping was used in 47.7% and left heart bypass (atriodistal) in 52.3%. Further surgical technique was identical: liberal intercostal or lumbar artery reimplantation, cerebrospinal fluid drainage (since 1989), administration of a renal cooling solution, permissive mild hypothermia, and no pharmacologic protection. Both univariate and multivariate analysis were used.

RESULTS

The hospital mortality rate was 10.1% overall: 14.6% in the cross-clamp group, and 5.9% in the bypass group (p = 0.02). The risk of hospital death increased with aneurysm rupture (odds ratio 5.6) and when the patient needed postoperative dialysis (odds ratio 7.5). The use of left heart bypass had a mild protective effect on hospital death (odds ratio 0.56). The incidence of postoperative renal failure requiring dialysis was 8.3% overall: 10.9% in the cross-clamp group, and 5.9% in the bypass group (p = 0.16). After multivariate analysis, a longer operative procedure (odds ratio 1.01 per minute) and a longer reappearance time of blue dye in the urine (odds ratio 1.05 per minute) increased the risk of dialysis, whereas the use of atriodistal bypass reduced that risk (odds ratio 0.08). Paraplegia or paraparesis occurred in 10.9% of patients overall: 13.2% in the cross-clamp group, and 8.8% in the bypass group (p = 0.27). After logistic regression, rupture increased the risk of paraplegia or paraparesis (odds ratio 3.2) and dissection reduced it (odds ratio 0.23).

CONCLUSIONS

The use of atriodistal bypass is beneficial in patients who had thoracoabdominal aortic aneurysm repair. Hospital mortality rates, postoperative dialysis, and paraplegia/paraparesis were reduced.

Left heart bypass reduces paraplegia rates after thoracoabdominal aortic aneurysm repair

BACKGROUND

The optimal strategy for spinal cord protection during thoracoabdominal aortic aneurysm (TAAA) repair remains unclear. We evaluated the protective effect of left heart bypass (LHB) during repair of extensive TAAAs.

METHODS

During a 12-year period, 710 patients had repair of extent I or II TAAAs. Left heart bypass was used in 312 (43.9%) patients. This group was retrospectively compared with 398 (56.1%) patients who had operations without LHB.

RESULTS

The overall 30-day survival rate was 94.8% (673 patients). In 42 patients, (6.0%) paraplegia or paraparesis developed. In patients with extent I TAAAs, paraplegia and paraparesis rates in LHB (6 of 123, 4.9%) and non-LHB (9 of 246, 3.7%) groups were similar (p = 0.576) despite longer aortic clamp times in the former group. In patients with extent II TAAAs, the LHB group had a lower incidence of paraplegia or paraparesis (9 of 189, 4.8%) compared with the non-LHB group (18 of 137, 13.1%; p = 0.007).

CONCLUSIONS

Left heart bypass reduced the risk of paraplegia and paraparesis in patients who had repair of extent I and II TAAAs.

Nonsurgical reconstruction of thoracic aortic dissection by stent-graft placement

BACKGROUND

The treatment of thoracic aortic dissection is guided by prognostic and anatomical information. Proximal dissection requires surgery, but the appropriate treatment of distal thoracic aortic dissection has not been determined, because surgery has failed to improve the prognosis.

METHODS

We prospectively evaluated the safety and efficacy of elective transluminal endovascular stent-graft insertion in 12 consecutive patients with descending (type B) aortic dissection and compared the results with surgery in 12 matched controls. In all 24 patients, aortic dissection was diagnosed by magnetic resonance angiography. In each group, the dissection involved the aortic arch in 3 patients and the descending thoracic aorta in all 12 patients. With the patient under general anesthesia, either surgical resection was undertaken or a custom-designed endovascular stent-graft was placed by unilateral arteriotomy.

RESULTS

Stent-graft placement resulted in no morbidity or mortality, whereas surgery for type B dissection was associated with four deaths (33 percent, P=0.09) and five serious adverse events (42 percent, P=0.04) within 12 months. Transluminal placement of the stent-graft prosthesis was successful in all patients, with no leakage; full expansion of the stents was ensured by balloon inflation at 2 to 3 atm. Sealing of the entry tear was monitored during the procedure by transesophageal ultrasonography and angiography, and thrombosis of the false lumen was confirmed in all 12 patients after a mean of three months by magnetic resonance imaging. There were no deaths or instances of paraplegia, stroke, embolization, side-branch occlusion, or infection in the stent-graft group; nine patients had postimplantation syndrome, with transient elevation of C-reactive protein levels and body temperature plus mild leukocytosis. All the patients who received stent-grafts recovered, as did seven patients who underwent surgery for type B dissection (58 percent) (P=0.04).

CONCLUSIONS

These preliminary observations suggest that elective, nonsurgical insertion of an endovascular stent-graft is safe and efficacious in selected patients who have thoracic aortic dissection and for whom surgery is indicated. Endoluminal repair may be useful for interventional reconstruction of thoracic aortic dissection.

Thoracoabdominal aortic aneurysm repair with sequential visceral perfusion: A technical note

The aim of this study was to develop a method for type III and type IV thoracoabdominal aortic aneurysm (TAA) repair that reduces ischemia time to the abdominal viscera, spinal cord, and lower extremities. Over a 25-month period, five type IV TAAs and three type III TAAs were repaired with a trifurcated polytetrafluoroethylene (PTFE) graft to bypass three of four visceral vessels and another graft to reconstruct the thoracoabdominal aorta. The trifurcated graft was sewn end-to-side to an unaffected area of descending thoracic aorta. Sequential end-to-end bypasses to the left renal, superior mesenteric, and celiac arteries followed this anastomosis. The remaining TAA was then replaced with a Dacron tube or bifurcated graft by clamping distal to the trifurcated graft so as to maintain visceral and left renal artery perfusion. Implantation of the right renal artery into the Dacron graft completed visceral artery reconstruction. The postoperative results indicate the feasibility of type III and IV TAA repair using tangential thoracic aortic clamping, individual aortic branch vessel reconstruction, and separate distal revascularization. This operative technique decreases ischemia time to the abdominal viscera, spinal cord, and lower extremities.

Mesenteric shunting decreases visceral ischemia during thoracoabdominal aneurysm repair

PURPOSE

A technique to decrease visceral ischemic time during thoracoabdominal aneurysm (TAA) repair is reported.

METHODS

A 10 mm Dacron side-arm graft is attached to the aortic prosthesis and positioned immediately distal to the planned proximal thoracic aortic anastomosis. On completion of the anastomosis, a 16 to 22 Fr perfusion catheter is attached to the side-arm graft and inserted into the orifice of the celiac axis or superior mesenteric artery. The cross-clamp is then placed on the aortic graft distal to the mesenteric side-arm graft. Pulsatile arterial perfusion is thus established to the visceral circulation while intercostal anastomoses or reconstruction of celiac, superior mesenteric, and right renal arteries is performed. Visceral ischemic time and the rise in end-tidal Pco2 after reconstruction of the visceral vessels in patients with mesenteric shunting was compared with a control group matched for aneurysm extent and treated immediately before use of the mesenteric shunt technique.

RESULTS

Between July and Oct, 1996, the technique was applied in 15 patients undergoing type I, II, or III TAA repair with a clamp and sew technique. The mean decrease in systolic arterial pressure was 12.5 +/- 8.5 mm Hg, with a concomitant rise in end-tidal Pco2 (mean, 6.9 +/- 5.8 mm Hg), after perfusion was established through the mesenteric shunt. Mean time to establishment of visceral perfusion through the shunt was 25.5 +/- 4.4 minutes; the resultant decrement in visceral ischemic time averaged 31.3 minutes (i.e., until celiac, superior mesenteric, and right renal arteries were reconstructed). Compared with controls, patients with shunts had a significantly decreased (6.9 +/- 5.8 versus 21.6 +/- 8.4 mm Hg; p = 0.0003) rise in end-tidal CO2 on completion of visceral vessel reconstruction.

CONCLUSIONS

In-line mesenteric shunting is a simple method to decrease visceral ischemia during TAA repair, and it is adaptable to clamp and sew or partial bypass and distal perfusion operative techniques.

Prevention of spinal cord ischaemic complications after thoracoabdominal aortic surgery

Since the publication of prior reviews on this topic, substantial clinical experience with a variety of operative strategies to prevent ischaemic cord complications has been reported. The available data on angiographic localisation of critical intercostal vessels, and, in particular, the evoked potential response to cross-clamping in patients indicates that risk of paraplegia varies considerably even among patients with equivalent TAA extent. Factors such as individual development of the ASA, patent critical intercostals, and the particulars of collateral circulation when intercostal aortic ostia are already occluded likely account for this variability. Information available from SSEP monitoring relative to the dynamic course of cord ischaemia with cross-clamping, and the parallel, if not, frustrating experience with angiographic localisation and intercostal vessel reconstruction indicates that a narrow temporal threshold of cord ischaemia with clamping is present in many patients. This reinforces the importance of both expeditious clamp intervals, critical intercostal re-anastomoses, and the desirability of neuroprotective manoeuvres during cross-clamp induced cord ischemia. As suggested in compelling experimental work our contemporary clinical experience, and predicted by prior reviewers, regional cord hypothermia provides significant promise for limiting or eliminating, in particular, immediate perioperative deficits. Avoidance of postoperative hypotension, spinal cord oedema, and preservation of critical intercostal vessels are additional strategies necessary to impact the development of delayed deficits favourably.

Initial experience with the Nikkiso centrifugal pump during thoracoabdominal aortic aneurysm repair

PURPOSE

Several centers use atriodistal bypass (ADB) as a protective adjunct against distal ischemia during extensive thoracoabdominal aortic aneurysm (TAAA) repair. Most current ADB circuits use indirect-drive centrifugal pumps. The purpose of this report is to describe our initial clinical experience with the Nikkiso pump, a more compact direct-drive centrifugal pump recently developed at Baylor, for ADB during TAAA repair.

METHODS

The Nikkiso pump was used for ADB perfusion in 10 consecutive patients during graft repair of TAAAs (six Crawford extent I and four extent II). Two patients had aortic dissection. In the four patients who had extent II repairs, selective renal and visceral perfusion was also performed with the Nikkiso pump.

RESULTS

No mechanical pump malfunctions or adverse events related to the device occurred. All 10 patients survived and were discharged from the hospital. No patient had paraplegia after surgery. Two patients had delayed lower extremity weakness after undergoing extent I repairs; both recovered and were ambulating at the time of discharge. No complications were associated with bleeding or cerebral, respiratory, renal, or hepatic function.

CONCLUSIONS

Our initial experience with the Nikkiso centrifugal pump during TAAA repair demonstrated excellent pump function that provided sufficient flow for both distal aortic and selective organ perfusion. The prevention of permanent spinal cord injury and distal organ failure was successful in this group.

Spinal cord complications of thoracoabdominal aneurysm surgery

BACKGROUND

Although rare, paralysis secondary to spinal cord ischaemia after aortic aneurysm surgery is a devastating complication. Many papers have been published on this topic but without a clear consensus on the best way of minimizing the problem. Recent articles have included advanced pharmacological approaches and the literature has been reviewed in light of these.

METHODS

Relevant papers were identified by an extensive text word search of the Medline database and a review of quoted articles.

RESULTS

Spinal cord complications are commoner after the repair of Crawford type II aneurysms than less extensive aneurysms. The presence of dissection, rupture and prolonged clamp times are associated with an increased incidence. About a quarter of all cord problems develop over 24 h after surgery and this may be due to a reperfusion type injury, although the exact mechanisms are by no means clear.

CONCLUSION

A combination of rapid surgery, left heart bypass for the repair of more extensive aneurysms, free spinal drainage and the avoidance of postoperative hypoxia and hypotension help to minimize spinal cord ischaemia. No pharmacological agent has yet been shown conclusively to improve outcome in the clinical setting.

Retrograde aortic and selective organ perfusion during thoracoabdominal aortic aneurysm repair

OBJECTIVES

To evaluate the possible prevention of renal and intestinal ischaemia during surgery of thoracoabdominal aortic aneurysms (TAAA) by use of retrograde and selective organ perfusion.

DESIGN

Prospective study.

MATERIALS

Thirty-three consecutive patients underwent TAAA repair, six of whom had a previous type B dissection: 14 patients (35%) had type I TAAA, 12 patients type II (32%), three patients type III (15%) and four patients type IV (18%). Mean age was 61 years (range 22-84 years).

METHODS

In patients with type I TAAA, retrograde aortic perfusion was performed by means of a left atrium femoral artery bypass or partial cardiopulmonary bypass. In type II, III and IV the same procedure was performed; however, following cross-clamping and opening of the abdominal aorta, the coeliac trunc, superior mesenteric and both renal arteries were selectively perfused with four Pruitt-catheters (9 Fr.), connected as an octopus to the extracorporal circulation.

RESULTS

All patients survived the surgical procedure. The minimal volume flow through each octopus catheter was 60 ml/min. Urine output was uninterrupted in all patients, irrespective of the aortic cross-clamp time. Only one patient (3%), who already had renal insufficiency, developed renal failure. Total in-hospital mortality was 15%, paraplegia occurred in 12%.

CONCLUSION

Retrograde aortic and selective organ perfusion is a safe technique and can prevent ischaemic renal and intestinal damage during cross-clamping of the aorta in thoracoabdominal aneurysm surgery.

Thoracoabdominal aneurysm repair: perspectives over a decade with the clamp-and-sew technique

OBJECTIVES

Experience over a decade with thoracoabdominal aortic aneurysm (TAA) repair using a clamp-sew technique was reviewed to compare overall results with alternative operative methods.

SUMMARY BACKGROUND DATA

Controversy continues as to the optimal technique for TAA repair, with frequent contemporary emphasis on bypass-distal perfusion methods. Proponents of this technique claim improved results compared to those of historic control subjects in the parameters of operative mortality, postoperative renal failure, and lower extremity neurologic deficit.

METHODS

Over the interval from 1987 to 1996, 160 TAA repairs (type I, 32%; type II, 15%; type III, 34%; and type IV, 19%) were performed in 157 patients with a mean age of 70 years and a male-to-female ratio of 1/1. Clinical features included ruptured TAA (10%), urgent operation (22.5%), and aortic dissection (18%). Operative management used a clamp-sew technique with regional hypothermia for spinal cord (epidural cooling, since 1993) and renal protection. Variables associated with the endpoints of operative mortality or major morbidity, particularly spinal cord injury, were assessed with Fisher exact test and logistic regression; late survival was estimated with the Kaplan-Meier method.

RESULTS

In-hospital mortality was 9% and was associated with operation for rupture (p < 0.005) or other acute presentation (p < 0.001). After multivariate analysis, the postoperative complication renal failure (relative risk, 6.5 [95% confidence interval, 1.8-23.6, p = 0.004]) and significant spinal cord injury (relative risk, 16.5 [95% confidence interval, 3.2-83.2, p = 0.001]) were associated independently with operative mortality. Paraparesis-paraplegia occurred in 7%, an incidence significantly (p < 0.001) less than that (18.7%) predicted for this cohort from published models. Variables associated (univariate analysis) with this complication included TAA rupture (p < 0.0001), other acute presentation or dissection (p < 0.001), prolonged (>6 hours) operation (p < 0.04), and excessive (>3 L) transfusions (p < 0.02). Operation for acute presentation or dissection (relative risk, 7.9 [95% confidence interval, 1.7-37.7, p = 0.009]) and prolonged surgery [relative risk, 7.5 [95% confidence interval, 1.5-35.3, p = 0.01]) retained independent association with paraplegia-paraparesis after multivariate analysis. Dialysis was needed in 2.5%. Late survival at 1 and 5 years was 86 +/- 2.9% and 62 +/- 5.8%, respectively.

CONCLUSIONS

These data compare favorably with those from contemporary reports using other operative strategies and do not support routine adoption of bypass-distal perfusion as the preferred technique for TAA repair.

Paraplegia after thoracoabdominal aortic aneurysm repair: is dissection a risk factor?

BACKGROUND

The association between aortic dissection and paraplegia or paraparesis (P/P) after thoracoabdominal aortic aneurysm repair is not clear.

METHODS

Six hundred sixty patients underwent thoracoabdominal aortic aneurysm repair from 1986 through 1995 using selective atriodistal bypass, liberal reattachment of critical intercostal arteries, moderate heparinization, and permissive mild hypothermia. Dissection was present in 163 patients (24.7%) and absent in 497 (75.3%).

RESULTS

Early mortality occurred in 7.4% overall, and did not differ between patients with nondissection, acute dissection, or chronic dissection. The incidence of P/P was 5.4% overall, 5.5% without dissection, and 5.0% with dissection. The risk of P/P for acute versus chronic dissection was 19% versus 2.9%, respectively (p = 0.011). Rupture and Crawford extent II were predictive of the development of P/P. In patients at high risk for P/P (ie, Crawford extent I or II), atriodistal bypass reduced the intercostal artery ischemic time, and reattachment of critical intercostal arteries (T8 to L1) reduced the incidence of P/P.

CONCLUSIONS

Acute dissection increases the risk of P/P after thoracoabdominal aortic aneurysm repair; using contemporary methods, however, chronic dissection does not increase the risk of postoperative P/P. Critical intercostal artery reattachment and atriodistal bypass are beneficial in patients undergoing extensive repairs.