Transperitoneal versus retroperitoneal suprarenal cross-clamping for repair of abdominal aortic aneurysm with a hostile infrarenal aortic neck

Infrarenal abdominal aortic aneurysms (AAAs) with a hostile infrarenal aortic neck unfit for endovascular aneurysm repair (EVAR) are more likely to require open repair with suprarenal aortic cross-clamping. We compared the results of the transperitoneal versus retroperitoneal approaches for repair of infrarenal AAA requiring suprarenal cross-clamping and the relative frequency of such techniques after incorporating EVAR into our clinical practice. From January 1998 through September 2005, 478 elective infrarenal aortic aneurysms were repaired. There were 160 (33%) open repairs (71% transperitoneal and 29% retroperitoneal) and 318 (67%) endovascular repairs. In 38 cases (24%) suprarenal cross-clamping was performed (47% transperitoneal and 53% retroperitoneal incisions) for a hostile infrarenal neck. A hostile aortic neck was defined as severe angulation (>60 degrees ), short neck (<15 mm), extensive calcification, or circumferential thrombus. The median age was 70 years; 47% were men; 16% had diabetes mellitus, 29% pulmonary disease, 53% coronary artery disease, and 11% renal insufficiency. The median aneurysm size was 6.0 cm. A retrospective analysis was performed to compare 30-day postoperative outcomes between the trans- and retroperitoneal patient cohorts. The results were determined for two time periods to assess whether open repair with suprarenal cross- clamping was being performed more frequently as a result of increased utilization of EVAR in the contemporary period. After 2002, EVAR increased from 60% to 71% (p = 0.04) while open repair declined from 40% to 29% (p = 0.01). The retroperitoneal approach doubled from 19% to 39%, while the transperitoneal approach decreased from 81% to 61% (p = 0.02). Suprarenal cross-clamping increased by 11% after 2002. There was no significant difference in age, sex, aneurysm size, or comorbidities between the trans- and retroperitoneal groups with suprarenal cross-clamping. The 30-day mortality was 2/38 (5%) and occurred only in the transperitoneal group. The transperitoneal approach was associated with significantly greater blood loss and longer suprarenal cross-clamp times (2,400 vs. 1,800 mL and 38.0 vs. 29.5 min; p = 0.03), but there were no significant differences in 30-day postoperative complications. In our 7 years' experience, there has been a gradual increase in the utilization of EVAR for infrarenal AAAs. At the same time, more infrarenal AAAs with hostile aortic necks requiring suprarenal aortic cross-clamping were encountered. In such instances, the retroperitoneal approach is safer, with less perioperative blood loss and shorter suprarenal cross-clamp time. This is likely attributed to better exposure of the suprarenal abdominal aorta, allowing a more secure proximal anastomosis.     

The effect of suprarenal cross-clamping on abdominal aortic aneurysm repair.

Two hundred five patients who underwent elective abdominal aortic aneurysm repair were divided into two groups: those who underwent infrarenal cross-clamping alone (n = 166) and those who underwent suprarenal cross-clamping alone or combined with infrarenal cross-clamping (n = 39). Mortality was comparable between groups (1.2% for infrarenal cross-clamping vs 2.6% for suprarenal cross-clamping). Transient renal insufficiency was more frequent in the suprarenal group than in the infrarenal group (28% vs 10%), but dialysis rates (3% for suprarenal vs 2% for infrarenal) were similar. Cardiac morbidity was comparable between groups as well. Operating room data reflected the technical challenge of complex aneurysm repairs. The retroperitoneal approach was the preferred exposure in the suprarenal group since better access to the suprarenal aorta may be achieved with this technique. While abdominal aortic aneurysm repairs requiring suprarenal cross-clamping remain a technical challenge, the risks are not formidable and suprarenal cross-clamping should be considered when confronted with difficult periaortic dissection.     

Results of supraceliac aortic clamping in the difficult elective resection of infrarenal abdominal aortic aneurysm

We have used clamping of the aorta above the celiac axis (SC) in 30 of 431 elective resections of infrainguinal abdominal aortic aneurysms (AAA) during the past five years as an alternative to a difficult aortic cuff dissection. The results of SC clamping in these 30 patients are compared with the results of 379 routine aneurysm resections with infrarenal (IR) clamping and 22 additional aneurysm resections where the clamp was placed immediately above the renal arteries. These difficult cuff dissections occurred in 12 patients with inflammatory AAA, in 11 patients with juxtarenal AAA, and in seven patients with recurrent or noninfected false AAA of the proximal cuff. Patients with ruptured or suprarenal aneurysms and those undergoing combined operation for a visceral ischemic syndrome and an aneurysm were excluded from this study. Patients with SC clamping had similar operative mortality rates, comparable renal function, and frequency of cardiac events as patients with IR clamping. Blood loss was slightly higher in the SC group (p = 0.07) and serum aspartate amino transferase (AST) levels were three times higher than in the IR group; however, this was of no clinical significance. In contrast, those 22 patients whose aortas were clamped immediately above the renal arteries (AR) had higher perioperative mortality rates (2% IR, 3% SC vs 32% AR) and a higher incidence of kidney failure requiring dialysis (1% IR, 3% SC vs 23% AR). The mean values of serum creatinine and blood urea nitrogen were also significantly higher in the AR group when compared with both the IR and the SC groups (IR: 25 and 1.5 mg/dl, respectively; SC: 27 and 1.8 mg/dl; AR: 41 and 3.5 mg/dl). The single most important risk factor accounting for the differences between clamping above the celiac artery and clamping above the renal arteries was the presence of atherosclerotic debris in the nonaneurysmal, juxtarenal aortic segment. Clamping the aorta with juxtarenal atherosclerosis caused either atheroembolization to kidneys, legs, and intestine or injury to the aorta, renal arteries, or both; it was the cause of morbidity in all five cases of kidney failure requiring dialysis and accounted for all seven of the deaths in the AR group. SC clamping does not add risk to the patient undergoing resection of an infrarenal AAA and is the preferred method of achieving proximal control of the infrarenal aorta when a a hazardous cuff dissection is likely.(ABSTRACT TRUNCATED AT 400 WORDS)     

Comparative early and midterm results of open juxtarenal and infrarenal aneurysm repair

Background and aims Since the introduction of endovascular aortic aneurysm repair (EVAR) for aortic aneurysms, the number of juxtarenal aortic aneurysms (JRA) has been growing steadily due to selection bias (neck morphology for EVAR). This case-match study compares the perioperative outcome and midterm results of suprarenally clamped JRA with infrarenal aortic aneurysms (AAA). Methods From 1997 to 2004, patients who received open surgery with suprarenal clamping for JRA were included in the study and compared to matched patients with infrarenal clamping (AAA). Measurements analyzed were the in-hospital mortality and morbidity. Midterm results were obtained through clinical investigation and magnetic resonance angiography imaging. Results Thirty-five patients (mean age, 68.4 years; 30 male and 5 female) received suprarenal cross-clamping for JRA. The overall in-hospital mortality for JRA and for the controls (AAA) with elective aortic repair was 4.5% (6.1% JRA; 3% AAA, p = 0.058). The morbidity of JRA was elevated according to the rate of pulmonary complications (p = 0.021) and the need for re-operation (p = 0.019). The mean follow-up time was 2.3 years (range, 8–96 months). At follow-up, 28 patients (80%) from the JRA group and 29 patients from the AAA group (82.9%) were alive. Conclusion Open aortic surgery for JRA with the need for suprarenal cross-clamping shows a slightly elevated in-hospital mortality rate without statistical significance and equal midterm mortality results in comparison with infrarenally clamped aortic aneurysms.     

Critical Analysis of Outcome Determinants Affecting Repair of Intact Aneurysms Involving the Visceral Aorta

Visceral (mesenteric and/or renal) ischemia/reperfusion phenomena likely contribute to the greater operative risk associated with pararenal and lower thoracoabdominal aortic aneurysm (TAA) repair. To differentiate the relative adverse effects of aortic clamp level, visceral ischemic duration, and various pre- and perioperative factors shared with infrarenal aneurysm patients, a comparative analysis of early and late outcomes after open repair of intact infrarenal and visceral aortic aneurysms was undertaken. A retrospective review of our university experience from 1993-1999/2002 revealed 549 patients (mean age 70 ± 8 years, 11% female) undergoing open repair of intact, degenerative aneurysms of the infrarenal (n = 391, 71%), juxtarenal (n = 78, 14%), suprarenal (n = 35, 7%), and type IV (n = 40, 7%) and type III (n = 5, 1%) TAA segments. All pararenal aneurysms required suprarenal (SR) or supravisceral (SV, above celiac or superior mesenteric artery) clamp placement. Concomitant renal reconstruction was done in 30% of visceral aortic and 3% of open infrarenal aneurysm repairs. Thirty-day adverse outcomes [death, renal failure (creatinine 2 × baseline or new dialysis), visceral (bowel, hepatic, renal, spinal cord, multiple organ dysfunction), and nonvisceral (cardiac, pulmonary, procedural) complications] were analyzed relative to patient and operative factors using univariate comparisons and multivariate stepwise logistic regression. Perioperative mortality rates varied significantly between aneurysm locations (infrarenal 2.1%, juxtarenal 2.6%, suprarenal 11.4%, TAA 13.3%; p < 0.01) and for clamp locations (infrarenal 2.1%, SR 3.0%, SV 10.8 %; p < 0.01) but were not different between juxtarenal (1.8% vs. 4.4 %) and SR (9.1% vs. 12.5%) aneurysms requiring SR or SV clamping, respectively. Visceral ischemic time (VIT) during SR or SV clamping, and not clamp location, was the only independent predictor of operative mortality [odds ratio (OR) = 10.8, 95% confidence interval (CI) 4-29]. Sensitivity analyses revealed VIT > 32 min to be the strongest predictor of early death. Visceral complication or renal failure affected 34% and 23% of visceral aortic (5% dialysis) and 7% and 5% (1% dialysis) of infrarenal repairs, respectively. VIT > 32 min, SV clamp placement, diabetes, and inflammatory aneurysm repair were each predictive of visceral complications and/or renal failure. Five-year survival rate was similar after visceral aortic (70%) and infrarenal (75%) repairs but negatively impacted only in patients with prior infrarenal abdominal aortic aneurysm repair and recurrent aneurysms (OR = 2.8, 95% CI 1.2-6.9). The high incidence of early adverse outcomes following repair of pararenal and lower thoracoabdominal aneurysms is primarily associated with excessive periods of renal and/or gut ischemia during visceral aortic clamp placement. However, nearly equivalent early and late survival was seen for visceral aortic and infrarenal repairs when VIT < 32 min was achieved.Presented at the Twenty-eighth Annual Meeting of the Southern Association for Vascular Surgery, Rio Grande, Puerto Rico, January 14-17, 2004.     

Management of juxtarenal aortic aneurysms and occlusive disease with preferential suprarenal clamping via a midline transperitoneal incision: technique and results

Surgical management of juxtarenal aortic (JR-Ao) aneurysms and occlusive disease may include supraceliac aortic clamping, a retroperitoneal approach, or medial visceral rotation. The authors report their results using preferential direct suprarenal aortic clamping via a midline transperitoneal incision. Between July 1, 1992, and July 31, 2001, they treated 58 patients with JR-Ao disease (44 aneurysmal, 14 occlusive) via a midline incision without medial visceral rotation. Preferential suprarenal aortic clamping was used in 53 cases (42 proximal to both renal arteries, 11 proximal to the left renal artery only) and supraceliac or supramesenteric clamping in 5 cases when there was insufficient space for an aortic clamp between the superior mesenteric artery and renal arteries. This strategy avoided mesenteric ischemia associated with supraceliac clamping in the majority of cases and afforded better exposure of the right renal artery than obtainable with a left retroperitoneal approach or medial visceral rotation. Eleven patients underwent concomitant renal revascularization. Critical adjuncts included the following: (1) selective left renal vein (LRV) division if the vein stump pressure was < 35 mm Hg (suggesting sufficient renal venous collaterals existed), (2) bilateral renal artery occlusion during aortic clamping to prevent thromboembolism, (3) flushing of aortic debris before restoring renal perfusion, and (4) routine administration of perioperative intravenous mannitol and renal-dose dopamine. Patients with type IV thoracoabdominal aneurysms, ruptured aneurysms, or JR-Ao disease approached via a retroperitoneal incision (severely obese patients, re-do aortic surgery) were excluded. No patients died or required dialysis during their hospital stay. The LRV was divided in 12 (21%) cases and reanastomosed in 2 cases (elevated stump pressures). The average suprarenal clamp time was 26 minutes (range, 10-60). Postoperative serum creatinine remained > 0.5 ng/dL above baseline in 3 (5%) patients. These results support suprarenal aortic clamping with a midline transperitoneal incision as the optimal strategy for treating juxtarenal aortic aneurysms and occlusive disease. The authors believe that selective left renal vein division enhances juxtarenal aortic exposure, and routine administration of renal protective agents, along with occlusion of both renal arteries during suprarenal aortic clamping, are critical adjuncts in performing these operations.     

Suprarenal aortic cross-clamping and renal function

Renal failure occurs in 1-13% of abdominal aortic reconstructions. In our survey of 81 abdominal aortic aneurysms, out of 100 abdominal aortic operations, suprarenal cross-clamping was necessary in 4 cases, with 1 transient postoperative dialysis, followed by a fully restored renal function in 19th postoperative day. Among the cases with infrarenal aortic cross-clamping, one patient died owing to colonic infarction, another patient presented progressive and persistent renal damage. From our experience, literature results and knowledge about renal physiopathology, it must be stressed that during and after abdominal aortic operations not only the manouvres of supra or infrarenal aortic clamping, but also concomitant cardiac diseases, the share of body fluids, and consequent hydroelectrolytic changes could affect the renal function. All these factors, and not only the technical aspects, should be considered with the aim of doing a correct prevention of the postoperative renal failure.     

Totally laparoscopic juxtarenal aortic anastomosis: an experimental study

The surgical management of juxtarenal aneurysms necessitates suprarenal aortic clamping and control of the renal arteries. We attempted to reproduce this procedure laparoscopically. Five female piglets were submitted to a totally laparoscopic approach of the aortoiliac segment. After laparoscopic control of the renal arteries and suprarenal clamping, a 6-mm Dacron tube graft was anastomosed to the juxtarenal aorta. After the procedure, a midline laparotomy allowed verification of the patency of the renal arteries and the quality of the anastomosis. Mean operative time was 198 minutes (range, 170-240 minutes). The dissection took an average of 92 minutes (range, 75-110 minutes). The mean suprarenal aortic cross-clamp time was 46.3 minutes (range, 29.1-81.5 minutes), and the mean anastomotic time was 28.9 minutes (range, 16.5-68.1 minutes). This study demonstrates in this animal model the feasibility of juxtarenal aortic anastomosis using a laparoscopic technique. Newly designed instruments should allow a shorter clamping time in the future.     

Open repair for pararenal abdominal aortic aneurysm: the strategy and pitfalls for safe surgery

Pararenal abdominal aortic aneurysm (PRAAA) includes two types of AAA : juxtarenal (JRAAA) and suprarenal (SRAAA). JRAAA is defined as aneurysms that extend up to but do not involve the renal arteries, necessitating suprarenal aortic clamping for repair. SRAAA is defined as aneurysms that extend up to the superior mesenteric artery, involving one or both renal arteries to be repaired. The surgical repair of PRAAAs requires more extensive aortic exposure and may result in ischemic injury to kidneys and visceral organs with higher morbidity and mortality compared with infrarenal AAAs. The four approaches to PRAAA repair are: 1) midline abdominal incision, transperitoneal, left renal vein divided or mobilized; 2) midline abdominal incision, transperitoneal, left medial visceral rotation technique 3) left flank incision, retroperitoneal; and 4) thoracoabdominal incision, thoracoretroperitoneal approach. The four positions of proximal clamping are: 1) suprarenal; 2) interrenal; 3) supramesenteric; and 4) supraceliac aorta. The surgical strategy should be determined based on computed tomography and magnetic resonance angiography imaging, and severe atherosclerotic or calcified aorta should never be clamped to prevent lethal embolic complications. Although developing fenestrated endovascular technology can be used in some cases of PRAAA repair, open surgery with thorough preoperative assessment and careful utilization of techniques to prevent visceral and renal ischemic injury is safe, effective, and durable and remains the gold standard for repair.     

Supraceliac aortic occlusion: A safe approach to pararenal aortic aneurysms

Twenty-four patients who underwent surgery for pararenal aortic aneurysms between January 1992 and April 1997 are reviewed. Eighteen patients had primary atherosclerotic aneurysms, three patients had symptomatic infected aneurysms, two patients had an aneurysm proximal to a prior aortic repair, and one patient had a pseudoaneurysm of a proximal aortic graft anastomosis. Thirteen patients underwent elective operation, five had an urgent operation, and six patients underwent an emergency procedure. Five patients had the proximal aortic clamp placed between the renal arteries (Group I), three patients had it placed between the superior mesenteric and the renal arteries (Group II), and 16 patients had it placed in a supraceliac location (Group III). Aneurysm size, age, sex, preoperative blood chemistries (including hemoglobin, hematocrit, liver function studies, and coagulation studies) were similar in all groups. Two patients in Group III were on hemodialysis preoperatively. Preoperative renal function (blood urea nitrogen and creatinine) was the same in all groups. Visceral ischémic time was 43.4 ± 9.37 min to the distal kidney in Group I, 26.6 ± 7.63 min in Group II, and 24.5 ± 6.22 min in Group III. Mean transfusion requirements were similar in all groups. Two patients in Group I required postoperative hemodialysis. No patient in either Group II or III developed renal insufficiency. Mortality was the same in each group but was related to the urgency of operation (elective 7.6%, urgent 40%, emergent 50%). Intrarenal clamping (Group I) was associated with more renal and gastrointestinal complications than either suprarenal or supraceliac clamping. Although suprarenal and supraceliac clamping had similar results, our preference is supraceliac clamping because it is technically easy to achieve and is associated with few end-organ complications.     

Open repair of pararenal aortic aneurysms

Surgical treatment of pararenal aortic aneurysms, if compared to open repair of infrarenal aneurysms, is characterized by more technical difficulties and haemodynamic problems. Since endovascular repair has become feasible in most cases of infrarenal aneurysms, surgical treatment of pararenal aneurysms is a matter of great interest for vascular surgery. Detection of pararenal aneurysms needs a careful preoperative diagnosis, assessment of cardiac, renal and pulmonary status of the patient and planning of the surgical intervention. The surgeon needs to face an extended proximal aorta exposure, to manage the left renal vein and to choose an appropriate clamping site. Then a skilled and quick reconstruction of the visceral arteries is fundamental to minimize organ disfunction. Coupled intraoperative selective perfusion of visceral arteries and systemic administration of nephroprotective drugs optimizes organ protection during ischemia. To better define challenges, risks and results, we reviewed our experience with the treatment of pararenal aortic aneurysms. In the period between January 1993 and May 2003, 98 consecutive patients underwent surgery for pararenal aneurysms at our Institution. We treated 98 pararenal aneurysms, divided in 68 juxtarenal and 30 pararenal ones. In the juxtarenal aneurysms group, the 30 days mortality rate was 5.8% (4/68); 3 of these patients underwent urgent operation for ruptured aneurysm. In the suprarenal aneurysms group, the 30 days mortality rate was 3.3% (1/30). In conclusion pararenal aneurysm repair is a safe procedure, especially if performed electively, and represents an interesting field of research to improve surgical and anesthesiologic techniques.     

Management of juxtarenal aortic occlusions: Technique for suprarenal clamp placement

Atherosclerotic occlusion of the entire infrarenal abdominal aorta can produce gangrene, rest pain or claudication and can progress to involve the renal artery origins. Features of the operative technique for treating these juxtarenal aortic occlusions include self-retaining retraction, mobilization of the left renal vein with division of all non-renal branches, exposure of the suprarenal aorta and renal arteries by division between clamps of the surrounding paraaortic fibroareolar tissue and fat, sharp division of crural attachments to the aorta, control of the two renal arteries with doubled vessel loops and then direct vertical clamping of the suprarenal aorta. Through an arteriotomy below the renal arteries, 2–4 cm of pararenal aorta are cleared of thrombus and atherosclerotic debris under direct vision. After transfer of the suprarenal clamp to an infrarenal position, conventional aortobifemoral bypass is then performed. In a series of 18 patients with juxtarenal aortic occlusion managed by this technique, suprarenal clamp time ranged from 4 to 25 minutes (mean, 13 minutes). There was no morbidity from renal failure or emboli and no mortality. This technique allows for deliberate, careful disobliteration of the pararenal and infrarenal aorta and minimizes the risk of renal embolization.     

Juxtarenal aneurysm. Comparative study with infrarenal abdominal aortic aneurysm and proposition of a new classification.

OBJECTIVE: to propose an anatomical classification of juxtarenal aortic aneurysm (JRA) that relates to their epidemiology and the result of surgical repair. MATERIAL AND METHODS: retrospective study of 53 JRA and 376 infrarenal aortic aneurysm (AAA) operated between January 1989 and August 1999. RESULTS: perioperative mortality after JRA repair was 19% for type A (interrenal), 13% for type B (aneurysm of one or two renal origins) and 4% for type C (no infrarenal neck). These differences were not significant. The overall perioperative mortality after JRA repair (11%) was significantly higher than mortality of AAA (3%p<0.01). Postoperative morbidity after JRA repair was 62% for type A, 75% for type B and 33% for type C. Postoperative morbidity after type B repair was significantly more frequent than after type C (p<0.001). The overall postoperative morbidity (51%) was significantly more frequent than after AAA repair (26%p<0.01). Preoperative ischaemic heart disease, aortic clamping above the coeliac axis and aortic proximal clamping longer than 30 min were significant risk factors for death after JRA repair. Survival by life-table analysis at five years after JRA repair and AAA repair were respectively 73%+/-7% and 76%+/-3%. CONCLUSION: there is a less favourable outcome after JRA repair as compared to AAA repair. The complexity of the surgical procedure requires accurate preoperative morphological assessment. The proposed classification of juxtarenal aneurysms may be helpful in guiding surgical access.     

Aortic clamping during elective operations for infrarenal disease: The influence of clamping time on renal function

OBJECTIVE: Aortic clamping proximal to the renal arteries is sometimes necessitated during infrarenal and juxtarenal aortic surgery and may be associated with an increased risk of renal ischemia and its consequences. The aim of the study was to estimate this risk and possibly identify a "safe" duration of renal ischemia. METHODS: Medical records were retrospectively reviewed for 60 consecutive patients (from 1987 to 1994) with abdominal aortic aneurysm (n = 43) and occlusive disease (n = 17) confined to the infrarenal or juxtarenal aorta who underwent infrarenal aortic reconstruction with temporary suprarenal clamping. The data obtained included risk factors, preoperative and postoperative serum creatinine level, blood urea nitrogen (BUN) value, proteinuria before surgery, and suprarenal clamping times. RESULTS: The mean age of the patients was 64.4 years (+/- 11.4 years), and 74% were men. Concomitant cardiac disease was present in 41% of the patients, and 9% had diabetes. The preoperative creatinine level was 1.21 mg/dL (+/- 0.54 mg/dL), and the BUN value was 16.6 mg/dL (+/- 7.8 mg/dL). During surgery, blood flow to the renal arteries was interrupted for 32.0 minutes (+/- 17 minutes). None of the surviving patients needed dialysis or had signs of acute renal failure after the operations, but transient azotemia (rise in creatinine level) occurred in 23% of the patients. Risk factors for this condition were high preoperative creatinine values and hypotension during surgery, but the main determinant was total renal ischemia time. Odds ratios for such transient renal dysfunction showed as much as a 10-fold risk when suprarenal aortic clamping was greater than 50 minutes as compared with 30 minutes or less. CONCLUSION: Postoperative renal function impairment is rare in this group of patients. If suprarenal clamp duration (renal ischemia time) is brief, patients with normal preoperative creatinine levels exhibit no increase or a marginal increase in BUN or creatinine levels after surgery. Accordingly, suprarenal aortic clamping less than 50 minutes in this patient group appears safe and well tolerated.     

Open Repair of Pararenal Aortic Aneurysms: Operative Management, Early Results, and Risk Factor Analysis

Surgical treatment of pararenal aortic aneurysms, if compared to open surgical repair of infrarenal aneurysms, is technically more demanding and characterized by problems related to organ ischemia. To better define challenges, risks, and results, we analyzed our experience with the treatment of pararenal aortic aneurysms. Between January 1993 and March 2005, 119 consecutive patients underwent surgery for pararenal aneurysms at our institution. A prospective analysis of results was performed. According to their localization, we treated 85 juxtarenal aneurysms and 34 suprarenal aneurysms. One hundred and three patients underwent primary repair of an atherosclerotic aneurysm, four patients underwent surgical repair of an anastomotic pseudoaneurysm, and eight patients underwent correction of an aneurysm of the pararenal aorta proximal to a previous infrarenal anastomosis. Four patients underwent emergency operation for a ruptured aneurysm. In the juxtarenal aneurysm group, the 30-day mortality rate was 4.7% (4/85) including three patients with ruptured aneurysm. In the suprarenal aneurysm group, the 30-day mortality rate was 2.9% (1/34). Preoperative renal insufficiency was present in 16 patients, respectively in 7 patients with juxtarenal aneurysms and in 9 patients with suprarenal ones. In 22 patients, we registered a transient increase in creatinine levels with return to baseline levels by discharge. Four patients required long-term dialysis. In three patients, a short period of dialysis was required. Clamping time longer than 30 min was associated with a higher risk of transient postoperative deterioration of renal function (p = 0.0073). Preoperative renal insufficiency was associated with a higher risk of persistent postoperative deterioration of renal function (p < 0.0001). Morbidity and mortality of elective surgery for pararenal aneurysms is acceptable. One of the main risks of this surgery is renal morbidity. Preoperative renal insufficiency and long periods of renal ischemia are associated with a higher risk of postoperative deterioration of renal function that is often, but not always, reversible. Nowadays, pararenal aneurysm repair is a safe procedure, especially if performed electively.     

Pararenal aortic aneurysms: definition, classification, directions for surgery

The formidable impact derived by the endovascular correction (Evar) of abdominal aorta aneurysms (AAA), has risen its classification aspects. The topographical criteria has assumed importance in decisional diagnostic-therapeutic strategy especially in cases of so called pararenal aneurysms (PRAA). DEFINITION: PRAA defines aneurysm being involved underenal juxtarenal aorta (JRA), or more rarely, suprarenal aorta with normal aortic diameter at level of celiac (JRA), or more rarely, suprarenal aorta with normal aortic diameter at level of celiac trunk. CLASSIFICATION: The morphologic-topographic aspect is considered in function of selection or eligibility of patients to Evar or standard open surgery, in the need of a suprarenal clamping for the tailoring of proximal anastomosis or anchorage of endoprotesis. Various specific classifications for these aneurysms have been proposed (Schumacher, 1997; Wolf, 2000; Ayari, 2001) that considers: 1. Aneurysm collar: short/long/tortuous, 2. Relations with renal arteries, 3. Relations with the left renal vein. DIRECTIONS FOR SURGICAL TREATMENT: The choice between the technical solution to prefer either open or endovascular surgery will have to consider a series of additional variables to the standard direction common to every AAA based on dimensions and morphology. Priority will have to be given to evaluating, using shared morphologic-topographical classification criteria, real incidence of PRAA-JRA (3%-20% in literature review); greater post opening mortality (1.3%-15.3%); dimensions (AAA with diameter > or = 5.5 cm in operating risk assessment of single patient, in clinical evolution and increase in the time of the lesion); in common occurrence in AAA of steno-obstructive lesions of renal arteries and involvement of same ones in the aneurysm collar in need of reconstruction and suprarenal aortic clamping.     

Hypothermic renal protection using cold histidine-tryptophan-ketoglutarate solution perfusion in suprarenal aortic surgery

We examined data of 21 patients who were treated with selective perfusion of both renal arteries with 500 mL of 8 degrees C histidine-tryptophan-ketoglutarate (HTK) solution each for renal protection during aortic surgery. Only the data from aortic surgeries with unavoidable suprarenal aortic cross-clamping for juxtarenal or suprarenal abdominal aortic aneurysms (AAAs) or high Leriche syndrome accompanied with stenosis of renal arteries are presented. Five patients underwent immediate surgery because of perforation of an AAA; the other 16 patients went through elective surgeries. In three cases (14%) stenosis of the renal arteries was diagnosed; nevertheless, implantation of an aortorenal bypass was necessary in seven patients. In total, 14 aortorenal bypasses were implanted (five venous grafts and nine prosthesis grafts). Four (19%) patients needed catecholaminergic support to establish stable circulatory conditions; in two (9%) of these cases additional ischemia of the colon was observed and sigmoidectomy was performed. All of these four patients underwent immediate surgery, and one died after surgery because of severe sepsis. In four cases postsurgical renal insufficiency was observed. Three of these patients were admitted for emergency surgery because of their hemodynamic situation due to perforation of the AAA. None of the patients needed chronic dialysis after surgery. Whereas in all patients who underwent elective surgery the renal function remained stable as judged by postoperative serum creatinine values, in five out of seven patients with aortorenal bypass surgery the renal function improved. Perfusion with cold HTK solution offers an additional procedure to protect renal function in patients undergoing elective surgery with suprarenal cross-clamping of the aorta.     

Pararenal aortic aneurysms: the future of open aortic aneurysm repair

PURPOSE: As endovascular stent graft repair of infrarenal abdominal aortic aneurysms (AAAs) becomes more common, an increasing proportion of patients who undergo open operation will have juxtarenal aneurysms (JR-AAAs), which necessitate suprarenal crossclamping, suprarenal aneurysms (SR-AAAs), which necessitate renal artery reconstruction, or aneurysms with associated renal artery occlusive disease (RAOD), which necessitate repair. To determine the current results of the standard operative treatment of these patterns of pararenal aortic aneurysms, we reviewed the outcome of 257 consecutive patients who underwent operation for JR-AAAs (n = 122), SR-AAAs (n = 58), or RAOD (n = 77). METHODS: The patients with SR-AAAs and RAOD were younger (67.5 +/- 8.8 years) than were the patients with JR-AAAs (70.5 +/- 8.3 years), and more patients with RAOD were women (43% vs 21% for JR-AAAs and SR-AAAs). The patient groups were similar in the frequency of coronary artery and pulmonary disease and in most risk factors for atherosclerosis, except hypertension, which was more common in the RAOD group. Significantly more patients with RAOD had reduced renal function before surgery (51% vs 23%). Supravisceral aortic crossclamping (above the superior mesenteric artery or the celiac artery) was needed more often in patients with SR-AAAs (52% vs 39% for RAOD and 17% for JR-AAAs). Seventeen patients (7%) had undergone a prior aortic reconstruction. The most common renal reconstruction for SR-AAA was reimplantation (n = 37; 64%) or bypass grafting (n = 12; 21%) and for RAOD was transaortic renal endarterectomy (n = 71; 92%). Mean AAA diameter was 6.7 +/- 2.1 cm and was larger in the JR-AAA (7.1 +/- 2.1 cm) and SR-AAA (6.9 +/- 2.1 cm) groups as compared with the RAOD group (5.9 +/- 1.7 cm). RESULTS: The overall mortality rate was 5.8% (n = 15) and was the same for all the groups. The mortality rate correlated (P <.05) with hematologic complications (bleeding) and postoperative visceral ischemia or infarction but not with aneurysm group or cardiac, pulmonary, or renal complications. Renal ischemia duration averaged 31.6 +/- 21.6 minutes and was longer in the SR-AAA group (43.6 +/- 38.9 minutes). Some postoperative renal function loss occurred in 104 patients (40.5%), of whom 18 (7.0%) required dialysis. At discharge or death, 24 patients (9.3%) still had no improvement in renal function and 11 of those patients (4.3%) remained on dialysis. Postoperative loss of renal function correlated (P <.05) with preoperative abnormal renal function and duration of renal ischemia but not with aneurysm type, crossclamp level, or type of renal reconstruction. CONCLUSION: These results showed that pararenal AAA repair can be performed safely and effectively. The outcomes for all three aneurysm types were similar, but there was an increased risk of loss of renal function when preoperative renal function was abnormal. These data provide a benchmark for expected treatment outcomes in patients with these patterns of pararenal aortic aneurysmal disease that currently can only be managed with open repair.     

Left retroperitoneal approach for aortic surgery

Twenty-eight consecutive patients underwent surgery of the abdominal aorta by the left retroperitoneal approach. There were 11 suprarenal, 12 juxtarenal, three complicated infrarenal aneurysms and two occlusive aortoiliac disease (considered to be at high risk) undergoing surgical repair. Twenty-one underwent a tube graft repair whilst seven had a bifurcation graft. There were five deaths in this series; four of which occurred in the initial 12 patients. In our initial experience using the left retroperitoneal approach the overall mortality rate was 17%, though this reduced to 6% for the latter half of the study. The retroperitoneal approach allows access to the supracoeliac aorta without the need for thoracotomy and this approach should be considered for all aortoiliac reconstructive surgery.The transabdominal route to the abdominal aorta remains the most commonly used approach. However, the left retroperitoneal approach offers advantages in high-risk patients and suprarenal and juxtarenal abdominal aortic aneurysms (AAA). This is our initial experience of 28 patients undergoing surgical repair of the abdominal aorta via the left retroperitoneal approach.     

Predictors of diffuse renal microembolization following endovascular repair of abdominal aortic aneurysms

We evaluated the incidence, risk factors, and clinical consequences of renal microembolic events following endovascular aneurysm repair using suprarenal or infrarenal fixation. Pre- and postoperative (1 month) computed tomographic angiograms were reviewed for new renal perfusion defects. Suprarenal aortic and infrarenal neck thrombus load was classified by circumference involved and thrombus thickness. Serum creatinine was measured preoperatively, on the first postoperative day, and 1 month postoperatively. Among 136 patients, 8 (5.9%) had bilateral microembolic cortical defects. Patients with moderate or severe suprarenal thrombus were more likely to have renal microemboli than those with no or mild suprarenal thrombus (17% vs 0%; p < .001). Similarly, patients with moderate or severe infrarenal neck thrombus were more likely to have renal microemboli than those with no or mild infrarenal thrombus (9.6% vs 1.5%; p = .08). Severe infrarenal thrombus was independently predictive of microembolization (odds ratio 15.0; 95% confidence interval 1.6-142; p = .018). There was no statistically significant difference in the incidence of renal microembolization when comparing suprarenal and infrarenal fixation (8.2% vs 4.0%; p = .47). Changes in creatinine from baseline were not different in those with or without renal microemboli. Renal microembolization is an uncommon but distinct radiographic finding that is more associated with significant neck thrombus than fixation level.