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.     

Importance of intercostal artery reattachment during thoracoabdominal aortic aneurysm repair

Purpose: We studied the relationship of neurologic deficit to ligation, reimplantation, and preexisting occlusion of intercostal arteries to determine which arteries and consequent management are most critical to outcome in thoracoabdominal aortic aneurysm repair. Methods: From February 1991 to July 1996, 343 patients with thoracoabdominal aortic aneurysms underwent repair by one surgeon. In this study, only Crawford types I, II, and III (n = 264) were considered. Of these, 110 (42%) were type I, 116 (44%) type II, and 38 (14%) type III. The adjuncts of distal aortic perfusion and cerebrospinal fluid drainage were used in 164 patients (62%). Data were analyzed by contingency table and by multiple logistic regression. Results: Early neurologic deficit occurred in 23 patients (8.7%), and late deficit in 10 patients (3.8%). Neurologic deficit in patients with at least one reimplantation and no ligation of arteries T11 or T12 occurred in 19 of 147 (12.9%). Neurologic deficit for occlusion of the same arteries occurred in 11 of 111 (9.9%), whereas for ligation of T11 and T12 neurologic deficit occurred in three of six (50%; reimplantation, p < 0.03; occlusion, p < 0.006). In addition, reimplantation of intercostal arteries T9 or T10 was significantly associated with reduced late neurologic deficit in multivariate analysis (p = 0.05). No other intercostal artery status was associated with modification of the neurologic deficit rate. Multivariate analysis showed type II aneurysms and acute dissections to be significantly associated with an increased risk of postoperative neurologic deficit (p < 0.0009, 0.002, respectively). Adjuncts were protective (p < 0.007), most often in types II and III (14.1% neurologic deficit in type II with adjunct, 35.3% without; 0% in type III with adjunct, 20% without). Conclusions: Patients with patent arteries at the T11/T12 level have highly variable outcomes depending on whether the arteries are reattached or ligated. Our data suggest that reimplantation of thoracic intercostal arteries T11 and T12 is indicated when these arteries are patent. Reimplantation of T9 and T10 lowers the risk of late neurologic deficit, probably by decreasing the spinal cord's vulnerability to changes in blood and cerebrospinal fluid pressure in the days after surgery. Adjuncts lower overall risk and provide adequate time for targeted intercostal artery reimplantation. (J Vasc Surg 1998;27:58-68.)     

Cefamandole levels during thoracoabdominal aortic aneurysm surgery

The pharmacokinetics of prophylactic antibodies may differ in cardiac and aortic aneurysm surgery for at least two reasons: aortic aneurysm surgery generally entails a greater blood volume loss and replacement, and aortic aneurysm surgery usually does not require extracorporeal cardiopulmonary bypass. We prospectively studied two different cefamandole dosing regimens in patients undergoing aortic aneurysm surgery (phase 1, 1 gm intravenously at the induction of anesthesia; phase 2, 2 gm intravenously at the induction of anesthesia followed by 1 gm intravenously every 2 hours during surgery). In phase 1 and 2 plasma levels were measured at the time of skin incision, aortic cross-clamping, aortic unclamping, and skin closure. In phase 2 cefamandole elimination in urine and cell-saver effluent was also determined. An adequate plasma level of 10 micrograms/ml was maintained in only 4 of 14 patients in phase 1, but in 10 of 10 patients in phase 2. Cefamandole loss in cell-saver effluent was 136 +/- 100 mg, which was 13% of the measured renally excreted amount. As has been previously shown in cardiac surgery, a cefamandole prophylactic antibiotic regimen of 2 gm intravenously at the induction of anesthesia followed by 1 gm every 2 hours during surgery provides a dependable and practical dosing regimen in patients undergoing aortic aneurysm surgery.     

Selective perfusion of segmental arteries in patients undergoing thoracoabdominal aortic surgery

BACKGROUND: Reattachment of segmental arteries is one method used to prevent paraplegia associated with thoracoabdominal aortic repair. Nevertheless, even when important segmental arteries are reattached, ischemia causing spinal injury may occur during anastomosis. METHODS: In 27 patients undergoing thoracoabdominal aortic repair, we attempted to perfuse the segmental arteries to be reattached with catheters connected to the distal bypass circuit. To identify perioperative risk factors for spinal ischemia, we examined changes in spinal somatosensory evoked potentials. RESULTS: A median value of four segmental arteries were perfused in 20 (74%) of the 27 patients. Changes in somatosensory evoked potential indicative of spinal ischemia were observed in 13 patients (48%). The only risk factor associated with changes in evoked potentials revealed by a multivariate analysis was prolonged aortic cross-clamp time (> 120 minutes). Of the 2 patients who suffered paraplegia, one had the longest clamp time and the other showed spinal cord necrosis due to embolic shower. CONCLUSIONS: Despite selective perfusion of segmental arteries, spinal ischemia associated with aortic cross-clamping may occur when clamping is prolonged over 120 minutes. Most of the changes appear to be reversible, however.     

Open surgery of thoracoabdominal aortic aneurysm

Postoperative paraplegia is a serious complication of reconstructive surgery on the thoracoabdominal or descending thoracic aorta, and the major cause is thought to be spinal cord ischemia during and after the procedure. Due to advances in anesthetic and surgical techniques, the incidence of intractable neurological complications has declined, but the rate of paraplegia or paraparesis is still within the range of 5-16%. Many methods have been devised to prevent this complication, such as 1) distal perfusion, 2) reimplantation of segmental arteries, 3) detection of the Adamkiewicz artery, 4) hypothermia, 5) cerebrospinal fluid drainage, 6) multisegmental aortic clamping, 7) motor-evoked potential monitoring, 8) epidural perfusion cooling, and 9) selective perfusion of the intercostal arteries and they can be utilized in combination.     

A counterpulsation technique for use during complicated aortic surgery with residual thoracoabdominal aortic aneurysm

Mechanical circulatory support can be difficult for patients with thoracoabdominal aortic disease. We herein describe a counterpulsation technique using an intra-graft balloon pump that can be safely used in the setting of thoracoabdominal aortic aneurysm remaining immediately after aortic root and arch replacement coupled with coronary artery bypass grafting.     

Acute diastolic dysfunction in thoracoabdominal aortic aneurysm surgery

PURPOSE: To report transesophageal echocardiographic (TEE) findings consistent with intraoperative acute diastolic dysfunction in a series of patients undergoing thoracoabdominal aortic aneurysm (TAAA) repair. METHODS: A series of nine consecutive patients underwent TAAA repair with intraoperative TEE monitoring. Surgical repair was performed with the adjunct of a left atrio-femoral bypass. Invasive arterial and venous pressures were monitored. Intraoperative TEE was utilized to assess the diastolic function before, and during aortic cross clamping. Diastolic dysfunction was defined as a mitral inflow pulsed wave Doppler (E: A ratio) < 1. RESULTS: All patients demonstrated an E: A ratio > 1 (1.3 +/- 0.08) before aortic cross clamping. During cross clamp, the E: A ratio decreased to < 1 (0.75 +/- 0.05) in six of nine patients consistent with diastolic dysfunction. The three patients who did not develop E: A changes were receiving ss-blockers pre-operatively. Patients with diastolic dysfunction were treated with nitroglycerin infusions, which resulted in restoration of their E: A ratios > 1 (1.2 +/- 0.09). Three of the patients with intraoperative diastolic dysfunction developed postoperative myocardial infarction. CONCLUSIONS: Chronic diastolic dysfunction is a well-known entity. This report describes acute diastolic dysfunction, which was observed frequently in patients undergoing TAAA during aortic cross clamp. Further research is required to confirm this phenomenon and determine its possible association with increased postoperative cardiac morbidity.     

Selective visceral and renal perfusion in thoracoabdominal aneurysm repair.

OBJECTIVE: Whether or not selective visceral and renal perfusion during thoracoabdominal aortic aneurysm (TAAA) repair has a protective effect on visceral and renal function remains unknown. The aim of this study was to clarify if selective perfusion has such an effect. METHODS: From May 1982 to December 1997, 82 consecutive patients underwent TAAA repair. Patients receiving hypothermic circulatory arrest or cooling of the kidney using Ringer's lactate solution were excluded, thus 73 patients were enrolled into this study. They were divided into three groups: those in whom selective visceral and renal perfusion was performed using a roller pump (n = 41), those in whom it was performed using a centrifugal pump with a reduced heparin regimen (n = 22) and those who underwent simple aortic clamping alone (n = 10). RESULTS: Serum creatinine, total bilirubin and alanine aminotransferase levels were elevated postoperatively in patients undergoing simple cross-clamp repair, but remained almost within normal limits in patients undergoing TAAA repair with selective visceral and renal perfusion. Urine output was more in selective perfused patients than in non-perfused patients. Renal dysfunction, defined by requirement of hemodialysis or by a serum level of creatinine above 3 mg/dl, occurred in four patients (10%) of the roller pump group and in two patients (9%) of the centrifugal pump group, while in four patients (40%) of the simple cross-clamping group. CONCLUSION: Our experience suggests that selective visceral and renal perfusion has a protective effect on hepato-renal function during TAAA repair.     

Spinal cord protection during thoracoabdominal aortic aneurysm repair; efficacy of distal aortic perfusion and segmental aortic clamping

Despite improvement in adjuncts for thoracoabdominal aortic aneurysms (TAAA) repairs, many devastating complications remains after the surgery. Our experience with these aneurysms has been reviewed in order to identify those methods at risk of major morbidity, as well as which further improvements required. During last 16 years, 53 consecutive patients were operated on TAAA. The mean age was 58 years. Twenty patients had dissecting aneurysms and 13 patients had had prior aortic surgery. A femoro-femoral bypass was used to maintain distal aortic perfusion in most patients. Reimplantation of intercostal or lumbar arteries under the multi-segmental aortic clamping is consistent in our technique. Motor evoked potentials (MEP) were measured to monitor spinal cord protection since 2000. The hospital mortality was 9.4% (5/53), 22.2% (2/9) for emergency operation and 15.4% (2/13) for patients with prior aortic surgery. The mortality for the first and elective operations was 3.2% (1/31). No any neurologic dysfunction was observed in all patients including the hospital deaths. In view of clinical results, our adjuncts and techniques are useful for prevention of spinal cord ischemia during the TAAA surgery.     

A new suture technique for reconstruction of intercostal arteries during thoracoabdominal aortic aneurysmal surgery.

Reconstruction of several intercostal arteries is inevitable in surgical treatment of thoraco-abdominal aortic aneurysm. A Dacron inverted-Y shaped graft was fashioned by cutting one of two graft legs and making an elliptical patch, like a cobra-head. Once the elliptical patch was sutured to the orifices of the intercostal arteries (usually from T9 to T12) with running sutures, selective intercostal arterial perfusion was initiated. After completion of aneurysmectomy, the distal end of the elliptical patch graft was sutured to the main tube graft. This method is easier and faster and results in a decreased incidence of spinal cord injury.     

Novel strategy for spinal cord protection during thoracoabdominal aortic aneurysm surgery using Doppler ultrasonography

Paraplegia remains one of the most serious complications after thoracoabdominal aortic aneurysm surgery. Spinal cord ischemia during the operation is thought to be the most important contributor to the development of this neurological deficit. So, it is important to preserve or reconstruct the critical segmental arteries for spinal cord protection. In order to identify the critical segmental arteries, we evaluate the segmental arteries by measuring the flow velocities using Doppler ultrasonography. The flow velocities are different among segmental arteries and some segmental arteries have no flow even though they are patent. Because we think that the segmental arteries with high flow velocities have much contribution to the spinal cord perfusion, we reconstruct or preserve such segmental arteries during the operation. We hope that this method would be clinically useful for spinal cord protection during thoracoabdominal aortic aneurysm surgery.     

The use of an aortoiliac side-arm conduit to maintain distal perfusion during thoracoabdominal aortic aneurysm repair

Thoracoabdominal aneurysm repair continues to be associated with a significant risk of operative complications, many of which are related to the prolonged period of aortic cross clamping inherent in the procedure. A variety of adjuvant techniques have been used in attempts to decrease morbidity, including atriofemoral extracorporal bypass, subarachnoid drainage, epidural cooling, and preliminary axillofemoral bypass. Herein is described a method to maintain distal perfusion with a side-arm conduit, originating from the most proximal aspect of the aortic graft and terminating on the left iliac artery. The technique has the potential to minimize hemodynamic instability while decreasing the period of pelvic and lower extremity ischemia and simplifying reattachment of aortic branch vessels. This method provides another option that can be considered in these technically demanding operative procedures.     

Individual temperature management during thoracoabdominal aortic aneurysm repair using separate perfusion of upper and lower torso

We report thoracoabdominal aortic aneurysm repair using separate perfusion of upper and lower torso that can control temperature of each organ individually. This novel modality can maintain mild hypothermic organ perfusion in upper torso and protect the heart under empty beating, while lower torso is further cooled to protect the spinal cord and visceral organs. Therefore this technique may be useful for patients with heart disease who require complex reconstruction of the intercostal arteries or visceral branches. We used this technique successfully in a patient who has a history of surgical repair of the aortic arch and the abdominal aorta. A 70-year-old male who had a history of abdominal aortic aneurysm repair and aortic arch aneurysm repair using stented elephant trunk underwent Crawford's type II thoracoabdominal aortic aneurysm repair. Three pairs of the intercostal arteries and 4 visceral branches were reconstructed using this technique successfully.