Early experience with the minimal extracorporeal circulation system (MECC) during thoracoabdominal aortic aneurysm repair.

AIM: The purpose of this report is to describe our early experience with a minimal extracorporeal circulation system (MECC), a compact closed heparin coated system consisting of a centrifugal pump and a membrane oxygenator, during thoracoabdominal aortic aneurysm (TAAA) repair. METHODS: Between January and December 2002 the MECC system was employed in seven consecutive patients (four TAAA type II, two TAAA type I and one TAAA type III according to the Crawford classification). In all patients distal aortic, selective renal and visceral perfusion was performed with this compact closed heparin coated system consisting of a centrifugal pump and a membrane oxygenator. RESULTS: The MECC system was used in all cases with no technical malfunctions. Six out seven patients were discharged from the unit. One patient developed paraplegia after TAAA repair and died on the third post-operative day from multi-organ failure. In this case the total spinal ischaemic time was 120 min and the distal aortic perfusion pressure was <50 mmHg. No cardiac, cerebral, renal, hepatic or bleeding complications were recorded in the remaining six patients. CONCLUSION: Our early experience with MECC during TAAA repair showed that it is feasible for distal aortic spinal and visceral selective perfusion. Further large clinical trials are required to determine the efficacy of this technique.     

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. (J Vasc Surg 1998;27:378-83.)     

Thoracoabdominal aortic aneurysm repair in patients with marfan syndrome.

OBJECTIVE: We assessed the surgical outcome of descending thoracic aortic aneurysm repair (DTAA) and thoracoabdominal aortic aneurym (TAAA) repair in patients with Marfan syndrome. METHODS: During a six year period, 206 patients underwent DTAA and TAAA repair. In 22 patients, Marfan syndrome was confirmed. The median age was 40 years with a range between 18 and 57 years. The extend of the aneurysms included 6 DTAA (1 with total arch, 2 with distal hemi-arch), 11 type II TAAA (2 with total arch, 3 with distal hemi-arch), 4 type III and one type IV TAAA. All patients suffered from previous type A (n=6) or type B (n=16) aortic dissection and 15 already underwent aortic procedures like Bentall (n=7) and ascending aortic replacement (n=8). All patients were operated on according to the standard protocol with cerebrospinal fluid drainage, distal aortic and selective organ perfusion and monitoring motor evoked potentials. In patients undergoing simultaneous arch replacement (via left thoracotomy), transcranial Doppler and EEG assessed cerebral physiology during antegrade brain perfusion. In four patients circulatory arrest under moderate hypothermia was required. RESULTS: In-hospital mortality did not occur. Major postoperative complications like paraplegia, renal failure, stroke and myocardial infarction were not encountered. Mean pre-operative creatinine level was 125mmol/L, which peaked to a mean maximal level of 130 and returned to 92mmol/L at discharge. Median intubation time was 1.5 days (range 0.33-30 days). Other complications included bleeding requiring surgical intervention (n=1), arrhythmia (n=2), pneumonia (n=2) and respiratory distress syndrome (n=1). At a median follow-up of 38 months all patients were alive. Using CT surveillance, new or false aneurysms were not detected, except in one patient who developed a visceral patch aneurysm six years after open type II repair. CONCLUSION: Surgical repair of descending and thoracoabdominal aortic aneurysms provides excellent short- and mid-term results in patients with Marfan syndrome. In this series, a surgical protocol with cerebrospinal fluid drainage, distal aortic and selective organ perfusion and monitoring motor evoked potentials resulted in low morbidity and absent mortality. These outcomes of open surgery should be considered when discussing endovascular aneurysm repair in Marfan patients.     

Cold visceral perfusion improves early survival in patients with acute renal failure after thoracoabdominal aortic aneurysm repair

INTRODUCTION: Despite advances in organ protection during thoracoabdominal aortic aneurysm (TAAA) repair, acute renal failure (ARF) remains a significant clinical problem, associated with increased morbidity and mortality. We studied outcome of ARF after TAAA repair in patients who underwent either warm or cold visceral perfusion. METHOD: Between 1991 and 2001 657 TAAA repairs were performed, of which 359 (55%) had either warm or cold visceral perfusion. Twelve patients with renal failure who had undergone preoperative dialysis were excluded from the study. Of the remaining 347 patients, ARF developed in 81 (23%) after TAAA repair. Forty-four (54%) of the 81 patients with ARF received cold visceral perfusion, and 37 (46%) patients received warm visceral perfusion. ARF was defined as either an increase of 1 mg/dL in serum creatinine (SCr) concentration per day for 2 consecutive days or dialysis requirement. Patient records were reviewed through hospital discharge. RESULTS: Twenty six (32%) of the 81 patients in whom ARF developed died, 17 of 37 (46%) patients in the warm perfusion group versus 9 of 44 (21%) patients in the cold perfusion group (P <.02). Median onset of ARF was on postoperative day 1 in both groups. Twenty-six of 81 (32%) patients recovered renal function, 10 of 37 (27%) patients in the warm perfusion group versus 16 of 44 (36%) patients in the cold perfusion group. Preoperative SCr concentration was predictive of recovery of renal function (odds ratio, 4.5 per mg/dL increase; P <.03) in patients who received either warm or cold visceral perfusion. CONCLUSIONS: ARF after TAAA repair remains a significant clinical problem. Recovery of renal function occurred in approximately one third of patients. Preoperative SCr concentration was the only significant determinant of recovered renal function. While cold visceral perfusion did not alter renal recovery, it significantly reduced hospital mortality.     

Selective visceral perfusion during thoracoabdominal aortic aneurysm repair.

PURPOSE: To evaluate the effectiveness of selective visceral perfusion during repair of an thoracoabdominal aortic aneurysm (TAAA), we compared the postoperative renal and hepatic functions (blood urea nitrogen, serum creatinine, total bilirubin, glutamate pyruvate transaminase) between the two groups with and without perfusion. PATIENTS AND METHODS: We operated on 52 patients with TAAA. Among them, the visceral vessels were reconstructed in 22 patients with selective visceral perfusion and in 12 patients without perfusion. The average selective perfusion time was 49.5+/-25.5 min. in the celiac and superior mesenteric arteries and 32.8+/-18.8 min. in the renal arteries. The average perfusion flow rate per each visceral vessel was 155.4+/-97.4 ml/min. RESULTS: There were five hospital deaths. There was no significant difference between the groups in the postoperative value of four factors. The selective perfusion time for vessel reconstruction in the selective visceral perfusion group was significantly longer than the arterial clamp time for vessel reconstruction in the non-perfusion group (49.5+/-25.5 min. vs. 25.6+/-13.4 min.). CONCLUSION: Our selective visceral perfusion method is not only beneficial for organ protection, but also provides us with the necessary time to reimplant the visceral as well as intercostal or lumbar arteries.     

RETRACTED: Prevention of renal failure in patients undergoing thoracoabdominal aortic aneurysm repair

OBJECTIVE: Renal failure is a potential complication after thoracoabdominal aortic aneurysm (TAAA) repair and is a significant risk factor for postoperative mortality. We assessed the results of distal aortic perfusion and continuous volume-controlled and pressure-controlled blood perfusion of the kidneys during TAAA repair in patients with preoperative normal and impaired renal function. METHODS: Surgical repair of TAAA was performed in 279 consecutive patients (type I, n = 90; type II, 117; type III, 42; type IV, 30). In 195 patients preoperative renal function was normal; however, in 84 patients renal insufficiency was diagnosed (serum creatinine concentration [SCr], 1.4-2.0 mg/dL, n = 46; SCr, 2.0-2.5 mg/dL, n = 20; and SCr, >2.5 mg/dL, n = 18). Renal perfusion was established with catheters connected to the left-sided heart bypass. Volume flow was assessed with ultrasound, and pressure channels in the catheters enabled pressure- controlled perfusion of the kidneys. RESULTS: Selective renal artery perfusion was achieved in all patients without technical problems or complications. In each catheter, mean arterial pressure was 69 mm Hg and volume flow was 275 mL/min. During aortic cross-clamping, urine output was uninterrupted, irrespective of clamp time. Most patients demonstrated limited or moderate increase in SCr concentration. In 17 patients (6%) SCr doubled, and peaked above 3 mg/dL, but returned to baseline levels within several days. Three patients (1%) required temporary dialysis but were discharged without further need for dialysis. In general, preoperative renal impairment did not worsen. CONCLUSION: Distal aortic and selective renal blood perfusion is an effective measure to protect renal function during TAAA repair, but only if perfusion is provided with adequate volume and pressure. This technique also averts dialysis in most patients with preoperative renal failure.     

Hybrid approach to thoracoabdominal aortic aneurysms in patients with prior aortic surgery

OBJECTIVE: The hybrid approach to the repair of thoracoabdominal aortic aneurysm (TAAA), consisting of visceral aortic debranching with retrograde revascularization of the splanchnic and renal arteries and aneurysm exclusion using stent grafts, has been previously described and may be considered particularly appealing in high-risk patients, especially those who have undergone prior aortic surgery. This study analyzed prospectively recorded data of a series of high-risk patients with prior aortic surgery who underwent hybrid TAAA repair at our institute and contrasted the outcomes with those of a similar group of patients who underwent conventional open TAAA repair. METHODS: Between 2001 and 2006, 13 patients (12 men) with a median age of 69.6 years (range, 35 to 82 years) underwent one-stage hybrid repair of TAAA (7 type I, 2 type II, 2 type IV, and 2 aneurysms of the visceral aortic patch). These patients, the hybrid group, had a history of aortic surgery (30.7% ascending, 30.7% descending, 46.1% abdominal aortic repair, and 15.4% redo TAAA) and were at high risk for open repair. The criteria used to define these patients as high risk and to indicate the need for hybrid treatment were American Society of Anesthesiologists (ASA) class 3 or 4 associated with a preoperative forced expiratory volume in 1 second (FEV1)<50%. In all cases, we accomplished partial or total visceral aortic debranching through (1) a previous visceral artery retrograde revascularization with synthetic grafts (single bypass, customized Y or bifurcated grafts), and (2) aortic endovascular repair with one of three different commercially produced stent grafts (Cook, W.L. Gore & Assoc, and Medtronic). We analyzed the results and compared the outcomes of the hybrid group with those of a similar group of 29 patients (25 men) with a median age 65.3 years (range, 58 to 79) selected from our overall series of 246 TAAA repairs between 1988 and 2005. These 29 patients, the conventionally treated group, were selected for having had aortic surgery (22% ascending, 38% descending, 42% abdominal aortic repair, and 10.3% redo TAAA), an ASA 3 or 4, a preoperative FEV1<50%, and a conventional open repair of TAAA (10 type I, 5 type II, 4 type III, 7 type IV, and 3 aneurysms of the visceral aortic patch). RESULTS: In the hybrid group, 32 visceral bypasses were completed and endovascular TAAA repair was successful in all cases. No intraoperative deaths occurred. Perioperative mortality was 23%, and morbidity was 30.8% (renal failure in 2, respiratory failure in 1, and delayed transient paraplegia in 1). At a median follow-up of 14.9 months (range, 11 days to 59.4 months), all grafts were patent at postoperative computed tomography angiography and no aneurysm-related deaths, endoleak, stent graft migration, or morbidity related to visceral revascularization had occurred. No conventionally treated patients died intraoperatively. Perioperative mortality was 17.2% and morbidity was 44.8% (respiratory failure in 7, coagulopathy in 1, renal failure in 2, and paraplegia in 3). At a median follow-up of 5.4 years (range, 1.7 to 7.9 years), no significant complications related to aortic repair occurred, except for three patients (10.3%) with asymptomatic dilatation of the visceral aortic patch<5 cm undergoing radiologic surveillance. CONCLUSION: Hybrid TAAA repair is technically feasible in selected cases. Perioperative morbidity and mortality were considerable in our subset of high-risk patients with prior aortic surgery, but no aneurysm-related or procedure-related complications were reported at mid-term follow-up. Hybrid TAAA repair did not lead to a significant improvement in outcomes compared with open TAAA repair in a similar group of patients. Larger series are required for valid statistical comparisons and longer follow-ups are necessary to evaluate the durability of hybrid repairs.     

Deployment of balloon expandable stents during open repair of thoracoabdominal aortic aneurysms: a new strategy for managing renal and mesenteric artery lesions.

OBJECTIVE: Patients undergoing graft repair of thoracoabdominal aortic aneurysms (TAAAs) often require concomitant correction of ostial stenoses or dissection involving visceral branches. The purpose of this report is to describe our initial experience with a new strategy for addressing these lesions during open TAAA repair-direct deployment of balloon expandable stents into the renal and mesenteric arteries. METHODS: Over a two-year period, 367 patients have undergone TAAA surgery. Balloon expandable stents were used to manage visceral branch lesions during open TAAA repair in 93 (25.3%) of these patients. Fifteen patients (16%) had preoperative renal insufficiency. After opening the aneurysm and exposing the branch artery ostia, premounted balloon expandable stents were deployed in the affected vessels under direct vision. Stents were deployed after an endarterectomy in 40 patients (43%). Eighty patients (86%) had stents placed in one or both renal arteries and 36 (39%) had stents placed in the celiac axis and/or superior mesenteric artery. Postoperative renal function was monitored with daily serum creatinine levels. RESULTS: There were nine early operative deaths (10%). Two patients (2%) had bleeding complications related to stenting, one of which died after developing multiple organ failure. Twelve patients (13%) developed renal failure, eight of which required dialysis. CONCLUSIONS: This study demonstrates the feasibility of treating ostial lesions of the visceral branches with balloon expandable stents during open TAAA repair. Despite a high prevalence of preoperative renal insufficiency, the incidence of postoperative renal failure was acceptable. This new strategy may be a valuable adjunct to TAAA repair and warrants further investigation.     

Surgical repair of thoracoabdominal aortic aneurysms

Morbidity and mortality following thoracoabdominal aortic aneurysm (TAAA) repair are tremendous. Preoperative assessment is essential in detecting cardiac and pulmonary risk factors in order to reduce cardiopulmonary complications. Paraplegia and renal failure are main determinants of postoperative mortality and therefore gained substantial attention during the last decades. Left heart bypass, cerebrospinal fluid (CSF) drainage and epidural cooling have significantly reduced paraplegia rate, however, this dreadful event still occurs in up to 25% of patients undergoing type II repair. Renal failure has been partly prevented by means of retrograde aortic perfusion and cooling but renal failure still remains a significant problem. We have evaluated the effects of protective measures aiming for reduction of paraplegia and renal failure. Monitoring motor evoked potentials (MEPs) is an accurate technique to assess spinal cord integrity during TAAA repair, guiding surgical strategies to prevent paraplegia. Selective volume- and pressure controlled perfusion is a technique to continuously perfuse the kidneys during aortic cross clamping and subsequent circulatory exclusion In patients with atherosclerotic thoracoabdominal aortic aneurysms, blood supply to the spinal cord depends on a highly variable collateral system. In our experience, monitoring MEPs allowed detection of cord ischemia, guiding aggressive surgical strategies to restore spinal cord blood supply and reduce neurologic deficit: overall paraplegia rate was less than 3%. We believe that these protective measures should be included in the surgical protocol of TAAA repair, especially in type II cases. Renal and visceral ischemia can be reduced significantly by continuous perfusion during aortic cross clamping in TAAA repair. Not only sufficient volume flow but also adequate arterial pressure appears to be essential in maintaining renal function.Obviously, endovascular modalities have been successfully applied in TAAA patients, the majority of which as part of hybrid procedures. Technological innovation will eventually cause a shift from open to minimal invasive surgical repair. At present, however, open surgery is considered the gold standard for TAAA repair, especially in (relatively) young patients and patients suffering from Marfan's disease.     

Surgical repair of thoracoabdominal aneurysms: patient selection,techniques and results

BACKGROUND: Repair of thoracoabdominal aortic aneurysms (TAAAs) continues to be a challenging task. Hemorrhagic shock, cardiac arrest and multisystem organ failures are the most frequent causes of death, and paraplegia and renal failure are the most devastating complications. METHODS: Flawless surgical technique and the use of adjuncts to protect key organs including the brain, heart, spinal cord, liver and kidneys affect outcome. Perfection in exposure and suturing technique decreases bleeding complications, shortens cross-clamp time and assures optimal, visceral, renal and lower extremity perfusion. Technical details include retroperitoneal abdominal aortic exposure, double thoracotomy for Type I and Type II aneurysms, and preservation of the diaphragm. The kidneys are protected by perfusion of iced lactated Ringers; visceral ischemia in Type I and Type II, aneurysms is diminished by using pulmonary vein-femoral artery pump with sequential clamping. Spinal cord protection is attempted by spinal fluid pressure monitoring and drainage, moderate general hypothermia, selective left heart bypass, reimplantation of critical intercostal arteries, monitoring somatosensory and somatomotor evoked potentials and epidural cooling of the spinal cord. RESULTS: Outcome in 203 patients (Group I) who underwent repair of TAAAs without epidural cooling was compared with outcome in 97 patients, 27 with thoracic aortic aneurysms and 70 with TAAA (Group II) who underwent repair using epidural cooling. In Group II paraplegia/parapesis occurred in 11.6%, not different from the 8.9% in Group I. Thirty day mortality for elective cases decreased from 14.6% (Group I) to 7.2% (Group II, P<0.05). CONCLUSIONS: Open surgical repair of TAAA carries elevated mortality and complication rates. The etiology of ischemic and reperfusion injury to the spinal cord is multifactorial and its prevention remains a formidable and as yet unresolved task. To select patients for surgical repair, the risk of TAAA rupture should be balanced against risks of perioperative mortality, paraplegia and renal failure.     

Endovascular treatment of thoracoabdominal aortic aneurysms

OBJECTIVE: This study assessed the role of multibranched stent grafts for thoracoabdominal aortic aneurysm (TAAA) repair. METHODS: Self-expanding covered stents were used to connect the caudally directed cuffs of an aortic stent graft with the visceral branches of a TAAA in 22 patients (16 men, 6 women) with a mean age of 76 +/- 7 years. All patients were unfit for open repair, and nine had undergone prior aortic surgery. Customized aortic stent grafts were inserted through surgically exposed femoral (n = 16) or iliac (n = 6) arteries. Covered stents were inserted through surgically exposed brachial arteries. Spinal catheters were used for cerebrospinal fluid pressure drainage in 22 patients and for and spinal anesthesia in 11. RESULTS: All 22 stent grafts and all 81 branches were deployed successfully. Aortic coverage as a percentage of subclavian-to-bifurcation distance was 69% +/- 20%. Mean contrast volume was 203 mL, mean blood loss was 714 mL, and mean hospital stay was 10.9 days. Two patients (9.1%) died perioperatively: one from guidewire injury to a renal arterial branch and the other from a medication error. Serious or potentially serious complications occurred in 9 of 22 patients (41%). There was no paraplegia, renal failure, stroke, or myocardial infarction among the 20 surviving patients. Two patients (9.1%) underwent successful reintervention: one for localized intimal disruption and the other for aortic dissection, type I endoleak, and stenosis of the superior mesenteric artery. One patient has a type II endoleak. Follow-up is >1 month in 19 patients, >6 months in 12, and >12 months in 8. One branch (renal artery) occluded for a 98.75% branch patency rate at 1 month. The other 80 branches remain patent. There are no signs of stent graft migration, component separation, or fracture. CONCLUSIONS: Multibranched stent graft implantation eliminates aneurysm flow, preserves visceral perfusion, and avoids many of the physiologic stresses associated with other forms of repair. The results support an expanded role for this technique in the treatment of TAAA.     

Collective experience with hybrid procedures for suprarenal and thoracoabdominal aneurysms

Not every patient is fit for open thoracoabdominal aortic aneurysm (TAAA) repair, nor is every TAAA or juxtarenal abdominal aortic aneurysm suitable for branched or fenestrated endovascular exclusion. The hybrid procedure consists of debranching of the renal and visceral arteries followed by endovascular exclusion of the aneurysm and might be an alternative in these patients. Between May 2004 and March 2006, 16 patients were treated with a hybrid procedure. The indications were recurrent suprarenal or thoracoabdominal aneurysms after previous abdominal and/or thoracic aortic surgery (n = 8), type I to III TAAAs (n = 3), proximal type I endoleak after endovascular repair (n = 2), penetrating ulcer of the juxtarenal aorta (n = 1), visceral patch aneurysm after type IV open repair (n = 1), and primary suprarenal aneurysm (n = 1). Eight (50%) of 16 patients were judged to be unfit for open TAAA repair. The hospital mortality rate was 31% (5 of 16). Four of five deceased patients were unfit for thoracophrenic laparotomy. Two patients died from cardiac complications and three from visceral ischemia. No spinal cord ischemia was detected, and temporary renal failure occurred in four patients (25%). The mean follow-up was 13 months (range 6-28 months). During follow-up, no additional grafts occluded and no patients died. Hybrid procedures are technically feasible but have substantial mortality (31%), especially in patients unfit for open repair (80%). They might be indicated when urgent TAAA surgery is required or when vascular anatomy is unfavorable for fenestrated endografts in patients with extensive previous open aortic surgery.     

Descending thoracic aorta aneurysmectomy: left-left centrifugal pump versus simple clamping technique

Forty-six patients who had had an elective repair of a descending thoracic aortic aneurysm were reviewed, in order to investigate the efficacy of support by a centrifugal pump on distal organ perfusion and spinal cord protection during cross-clamping of the thoracic aorta. Two concurrent groups were analysed: 36 patients (78%) were supported by left atriofemoral arterial bypass with a centrifugal pump and 10 (22%) had no distal circulatory support. No patient was fully heparinized. The demographic data and preoperative characteristics of the groups, including location and type of aneurysrn, were similar. The mean(s.d.) duration of cross-clamping was 37.8(16) min in the centrifugal pump group and 42.3(21) min in the simple clamping group. Preoperative haemodynamic and laboratory data were similar in both groups. During cross-clamping, parameters of pH and blood urea varied but were better in the centrifugal pump group; changes from pre-intervention to early aortic cross-clamping time were not significant (pH, P<0.0006; bases, P<0.0003). Differences in creatinine values were caused mainly by the change from pre-intervention to the first postoperative day (P<0.03); this continued throughout the hospital stay. The cerebrospinal fluid pressure measurement indicated a significant difference in time change (P<0.0001) and mean level over time (P<0.0002): levels were significantly lower in the centrifugal pump group throughout aortic cross-clamping. Three patients in the simple clamping group and none in the centrifugal pump group (P<0.02) required cerebrospinal fluid drainage. Paraplegia occurred in one patient (3%) in the centrifugal pump group and in one (10%) in the simple clamping group (P = n.s.). The overall in-hospital mortality rate was 9%, with 71% of all deaths occurring in patients who had an emergency repair of the aneurysrn. The cumulative 5-year survival rate was 72% in the centrifugal pump group and 84% in the simple clamp group (P = n.s.). The results confirm that patients offered centrifugal pump support are better stabilized metabolically, suggesting that spinal cord perfusion is improved.     

Surgical treatment of thoracoabdominal aortic aneurysm after repairs of descending thoracic or infrarenal abdominal aortic aneurysm.

OBJECTIVE: The outcome of thoracoabdominal aortic aneurysm repair after operations for descending thoracic or infrarenal abdominal aortic aneurysm was investigated. METHODS: Between May 1982 and July 2000, 102 patients underwent thoracoabdominal aortic aneurysm repair. Of these patients, 36 had previously undergone operations for descending thoracic or abdominal aortic aneurysm. To evaluate the influence of previous descending thoracic or infrarenal abdominal aortic aneurysm repair on the results of TAAA replacement, patients were divided into two groups: one group of patients who had previously undergone descending thoracic or infrarenal abdominal aortic aneurysm repair (group I, n=36) and one group of patients who had not previously undergone descending thoracic or infrarenal abdominal aortic aneurysm repair (group II, n=66). RESULTS: Patients with previous descending thoracic or infrarenal abdominal aortic aneurysm repair had more chronic dissection and extensive thoracoabdominal aortic aneurysm. The distal aortic perfusion time and total aortic clamp time were both longer in group I. The total selective visceral and renal perfusion time and operation time did not differ significantly between the two groups. In 30-day mortality rates were 5.5% in group I and 13% in group II. Major postoperative complications included paraplegia in 14% of patients in group I and 3.1% in group II, renal failure requiring hemodialysis in 22% of patients in group I and 19% of patients in group II, respiratory failure in 36% of patients in group I and 30% of patients in group II, postoperative hemorrhage in 11% of patients in group I and 16% of patients in group II. CONCLUSION: The presence of a previous descending thoracic or infrarenal abdominal aortic aneurysm did not adversely affect the outcome of thoracoabdominal aortic aneurysm repair.     

Renal perfusion during thoracoabdominal aortic operations: cold crystalloid is superior to normothermic blood

BACKGROUND: Renal failure remains a common complication of thoracoabdominal aortic aneurysm repair. The purpose of this randomized clinical trial was to compare two methods of selective renal perfusion--cold crystalloid perfusion versus normothermic blood perfusion--and determine which technique provides the best kidney protection during thoracoabdominal aortic aneurysm repair. METHODS: Thirty randomized patients undergoing Crawford extent II thoracoabdominal aortic aneurysm repair with left heart bypass had renal artery perfusion with either 4 degrees C Ringer's lactate solution (14 patients) or normothermic blood from the bypass circuit (16 patients). Acute renal dysfunction was defined as an elevation in serum creatinine level exceeding 50% of baseline within 10 postoperative days. RESULTS: One death occurred in each group. One patient in the blood perfusion group experienced renal failure requiring hemodialysis. Ten patients (63%) in the blood perfusion group and 3 patients (21%) in the cold crystalloid perfusion group experienced acute renal dysfunction (p = 0.03). Multivariable analysis confirmed that the use of cold crystalloid perfusion was independently protective against acute renal dysfunction (p = 0.02; odds ratio, 0.133). CONCLUSIONS: When using left heart bypass during repair of extensive thoracoabdominal aortic aneurysms, selective cold crystalloid perfusion offers superior renal protection when compared with conventional normothermic blood perfusion.     

Perfusion techniques for renal protection during thoracoabdominal aortic surgery

Open thoracoabdominal aortic aneurysm (TAAA) repair includes aortic clamping that interrupts antegrade blood flow to distal organs. Ischemia involving the kidneys can lead to renal failure and poor outcomes. To this end, prevention of ischemic kidney damage has led to several perfusion strategies that protect the kidneys during TAAA surgery. Options for renal perfusion include the use of passive shunts or mechanical circulatory support to deliver oxygenated blood continuously to the kidneys until normal aortic flow is re-established. An alternative approach, renal perfusion with cold crystalloid, has emerged as the preferred option of renal protection at several centers. Although there is considerable variation, several studies have demonstrated that cold crystalloid renal perfusion provides excellent protection, particularly in high-risk patients such as those with renal artery occlusive disease, preoperative renal dysfunction, or a ruptured aneurysm. Notably, recent consensus practice guidelines recommend either cold crystalloid or blood perfusion be considered for renal protection during TAAA repair. In this article, we discuss these various strategies for renal protection during TAAA repair and highlight the related technical aspects.     

Centrifugal pump support for distal aortic perfusion during repair of traumatic thoracic aortic injury

Paraplegia from ischemic injury of the spinal cord and renal failure from inadequate perfusion of the kidneys may occur from aortic cross-clamping during repair of traumatic thoracic aortic injuries. After Institutional Review Board approval, we retrospectively reviewed the charts of 26 patients surgically treated for traumatic transection of the descending thoracic aorta during a 14 year period (1987-2001), using centrifugal pump (Sarns) support for distal aortic perfusion. The study group comprised 19 males and 7 females, whose ages ranged from 15 to 69 years. For all but 1 patient, who fell from a flagpole, the injuries were incurred in motor vehicle accidents. Aortic cross-clamp time lasted between 5 to 78 min (median = 40 min). Mean arterial pressure ranged from 50 to 80 mm Hg (median = 70 mm Hg). All patients survived operation without developing paraplegia or renal failure. Distal centrifugal pump perfusion during repair of traumatic injury of the descending thoracic aorta is a valuable adjunct during surgical treatment and aids in preservation of spinal cord and renal function.     

Thoracoabdominal aortic aneurysm repair through redo left-sided thoracotomy

BACKGROUND: The outcome of thoracoabdominal aortic aneurysm repair through redo-left thoracotomy after operations for descending thoracic aortic aneurysms was investigated. METHODS: Between May 1982 and March 2003, 100 patients underwent thoracoabdominal aortic aneurysm repair in elective surgery without profound hypothermic circulatory arrest. Thirty of these patients had previously undergone operations for descending thoracic aortic aneurysms. To evaluate the influence of previous descending thoracic aortic aneurysm repairs on the results of thoracoabdominal aortic aneurysm replacements, patients were divided into two groups: (1) patients who had previously undergone descending thoracic aortic aneurysm repair (group I; n = 30), and (2) patients who had not previously undergone descending thoracic aortic aneurysm repair (group II; n = 70). RESULTS: The distal aortic perfusion time and operation time were both longer in group I than in group II, but there was no significant difference between the two groups in total selective visceral and renal perfusion time or aortic clamp time. In-hospital mortality rates were 13% in group I and 19% in group II (p = 0.52). Major postoperative complications included paraplegia (10% of patients in group I and 4.3% of patients in group II; p = 0.36), renal failure requiring hemodialysis (20% of patients in group I and 11% of patients in group II; p = 0.35), respiratory failure (30% of patients in group I and 19% of patients in group II; p = 0.22). CONCLUSIONS: Previously descending thoracic aortic aneurysm and redo-left thoracotomy do not adversely affect the outcome of thoracoabdominal aortic aneurysm repair.     

Fate of the visceral aortic patch after thoracoabdominal aortic repair.

OBJECTIVE: To analyse the fate of a visceral aortic patch (VAP) in patients that underwent thoracoabdominal aortic aneurysm (TAAA) repair. METHODS: We reviewed 204 consecutive patients (158 M, 46 F) treated for TAAA between 1988 and 2004. We performed VAP in 182 cases. Among the 149 survivors at 6 months, we followed 138 cases, mean follow-up 7 years (range 0.6-16 years). The mean graft diameter we used was 29mm (range 24-34mm) from 1988 to 1999 (83 patients), and 21.7mm (range 16-24mm) from 2000 to 2003 (55 patients). In 23% of cases we performed a separate bypass to the left renal artery. RESULTS: We observed 16 (12%) VAP dilatations (<5cm), 6 (4%) VAP aneurysms (>5cm) and one VAP pseudoaneurysm, at a mean time of 6 years after atherosclerotic TAAA was atherosclerotic repair. There were no VAP dilatations/aneurysms in the group of patients with separate left renal revascularization. Five VAP aneurysms were treated electively. In four cases the operation was performed with thoracophrenolaparotomy, in one case with a bilateral subcostal laparotomy. In all cases the visceral aorta was re-grafted. Reimplantation of a single undersized VAP was performed in one case, separate revascularization of visceral arteries was performed in the other four cases. Selective intraoperative hypothermic perfusion of visceral and renal arteries was used in all the patients. There was 1 perioperative death; 2 patients with preoperative renal failure required dialysis. The last VAP aneurysm has remained asymptomatic and stable at annual CT surveillance. The VAP pseudoaneurysm was successfully treated with an emergency thoracophrenolaparotomy and refashioning the left side suture line. CONCLUSIONS: Aneurysm of VAP is not uncommon in the patients operated on using larger grafts with a single VAP that includes the LRA (7.4%, 5/67 cases). Its treatment carries significant morbidity and mortality.     

Comparative study of hypothermic circulatory arrest and normothermic distal perfusion for thoracoabdominal aortic aneurysm repair

BACKGROUND: Hypothermic bypass with circulatory arrest for thoracoabdominal aortic aneurysm (TAAA) repair is employed for its protective effect on spinal cord function and because it avoids clamping the diseased aorta. However, organ dysfunction caused by reperfusion injury as well as bleeding tendencies due to deep hypothermia have been described. In this paper we compared the efficacies of the hypothermic and normothermic operations. METHODS: Between February 1996 and June 2000, 28 patients underwent thoracoabdominal aortic repair. Twenty-three patients were men, 5 were women, and the median age was 55.3 (range 23 to 75 years). Fourteen patients had aortic dissection, and 7 had Marfan syndrome. Fourteen patients required reconstruction of visceral arteries. Twelve patients underwent TAAA repair under deep hypothermic circulatory arrest (H group), and 15 under normothermic distal perfusion (N group), while 1 patient underwent a simple clamp procedure. Perioperative data and early outcomes were compared between groups. RESULTS: The overall 30-day mortality rate was 0%, but 3 patients (25.0%) in II group, and 1 patient (6.3%) in N group died during hospital stay. Operation time and bypass time were longer in H group than N group (operative time 793 min vs. 481 min (p < 0.05): cardiopulmonary bypass (CPB) time 255 min vs. 102 min (p < 0.05). Also, more intraoperative bleeding was found in H group than in N group (3,506 ml vs. 1,220 ml). Spinal cord neurologic deficit did not occur in either group. Respiratory failure occurred in 3 patients (25.0%) in H group and one (6.3%) in N group. Renal failure occurred in 3 (25.0%) in H group, and none in N group. CONCLUSION: Early and mid-term outcome of TAAA repair was almost satisfactory and without neurospiral complications. The deep hypothermic operation is more likely to induce postoperative respiratory and renal dysfunction than the normothermic operation. TAAA repair using deep hypothermic circulatory arrest should be limited to patients with TAAA involving the distal arch or a severely calcified aortic wall.