Suprarenal Clamping Research Articles

Open abdominal aortic aneurysm repair in octogenarians before and after the adoption of endovascular grafting procedures

This study evaluated (1) elective open abdominal aortic aneurysm repair (OAR) in patients aged > or =80 years before and after stent graft devices for endovascular aneurysm repair (EVAR) became commercially available and (2) the effect on perioperative (30-day) outcome of the anatomic constraints that led to EVAR being excluded for many of them. A review was conducted on the records of 111 patients aged > or =80 years who underwent elective OAR during a 14-year period at the University of Padua School of Medicine. Patients were separated into two groups: group 1 (n = 65) had OAR before and group 2 (n = 46) after an EVAR program was adopted at the medical school in mid-2000. Perioperative death and morbidity, location of proximal aortic clamp, management of the left renal vein, associated iliac aneurysmal or occlusive diseases, the type of surgical reconstruction, operating time, and lengths of stay in the intensive care unit and the hospital were recorded. All the data were compared between the two groups. Retroperitoneal approach, suprarenal clamping, left renal vein division, and longer operating room time were statistically more common in group 2 (36.9% vs 12.3%, P = .002; 15.2% vs 3.1%, P = .032; 23.9% vs 7.7%, P = .026; and 117 +/- 8 min vs 95 +/-7 min, P < .001, respectively). Although group 2 had significantly more iliac aneurysms (52.1% vs 32.3%; P = .036), the number of bifurcated reconstructions was comparable. The overall perioperative mortality rate was 1.8% (2 of 111), and the figures for groups 1 and 2 were comparable (3.1% vs 0%; P = .510). No deaths were cardiac related. Group 2 had a significantly higher incidence of kidney failure (8.7% vs 0%; P = .027). Kaplan-Meier analysis showed an overall 3-, 5-, and 10-year survival rate of 80.6%, 67.2%, and 59.4%, respectively, with a 3- and 5-year survival rate comparable between groups 1 and 2 (77.8% and 66.7% vs 87.8% and 45.8%, respectively; log-rank test, P = .921). Octogenarians can tolerate OAR with acceptable rates of perioperative mortality and morbidity. Although the complexity of OAR has increased significantly in the era of EVAR, the perioperative outcome has not changed.

The Relationship Between Volume and Outcome Following Elective Open Repair of Abdominal Aortic Aneurysms (AAA) in 131 German Hospitals

Objectives: Several studies indicate that high-volume hospitals have better results in open repair of unruptured abdominal aortic aneurysms (AAA). Up to now no studies had addressed this question in German hospitals. Design: Post-hoc-analysis from a prospective physician-led registry. Material and methods: Since 1999, the German Society for Vascular Surgery has conducted a prospective registry for open and endovascular repair of AAAs. This study includes 131 hospitals who conducted n=10163 elective open repairs for unruptured AAA between 1999 to 2004. All perioperative variables including annual volume as a continuous variable were analysed in a step-wise logistic regression model. In order to define a threshold annual volume an additional logistic regression analysis was performed by use of annual volume groups (0–9, 10–19, 20–29, 30–39, 40–49, 50 or more). The relationship between annual volume and further outcome parameters (length of procedure, blood transfusion, length of stay) were also analyzed. Results: The overall mortality rate was 3.2%. The stepwise logistic regression model identified the following predictors of an increased perioperative mortality: age (OR 1.084, 95% CI 1.066–1.102), AAA diameter (OR 1.008, 95% CI 1.001–1.016), length of procedure (OR 1.008, 95% CI 1.006–1.009), ASA-Score (OR 2.636, 95% CI 2.129–3.264), suprarenal clamping (OR 1.447, 95% CI 1.008–2,078), blood transfusion (OR 1.786, 95% CI 1.268–2.514). Annual volume was moderately predictive (OR 1.003, 95% CI 1–1.006) but failed to reach statistical significance (p=0.07). The analysis of volume groups identified a significantly higher risk for hospitals with an annual volume of 1-9 AAA-repairs by comparison to hospitals with an annual volume of 50 or more AAA-repairs (OR 1.903, 95% CI 1.124–3.222). Operations at low volume hospitals were also longer (p<0.001), with an extended postoperative stay (p<0.001) and a higher transfusion rate (p<0.001). Conclusions: Patient’s age, ASA classification, AAA diameter, length of procedure, suprarenal clamping and blood transfusion are predictive variables for an increased perioperative mortality in elective open AAA repair. Mortality is also increased by a low annual volume. Further studies are needed to examine whether these data are applicable to all German hospitals.

Acute and chronic open conversion after endovascular aortic aneurysm repair: A 14-year review

This study reviewed outcomes of patients requiring surgical conversion after endovascular abdominal aortic aneurysm (AAA) repair. Records for all patients undergoing open conversion after endovascular AAA repair were reviewed. From 1993 to 2006, 574 patients underwent endovascular repair for AAA. Seventeen patients, including three patients who underwent prior endovascular repair at other centers, required surgical conversion with complete (n = 9) or partial graft removal (n = 8). Five patients required immediate conversion (acute), and 12 underwent delayed conversion 4 to 72 months after endovascular repair. Indications for acute conversion were large type I endoleak (n = 3, 60%), including one patient with graft migration, and retroperitoneal bleeding (n = 2, 40%). Indications for chronic conversion were endoleak with increasing aneurysm size (n = 9, 75%), stent fracture without endoleak (n = 1, 8%), delayed retroperitoneal bleeding (n = 1, 8%), and infection (n = 1, 8%). Suprarenal aortic cross-clamping was required in two patients (12%), and endograft components were retained in eight (47%). An aortic occlusion balloon placed through the body of the existing endograft facilitated proximal control in three patients. There were two perioperative deaths in the acute conversion group (2/5; 40%) and none in the delayed conversion group (P = .04). Five-year actuarial survival was 71.9%. Mean follow-up was 41.6 +/- 32.2 months. Retained endovascular components in patients with partial graft removal remained stable during follow-up. Surgical conversion after endovascular AAA repair can be performed without suprarenal clamping in most patients. Endovascular aortic control with a balloon avoids suprarenal exposure. Partial endograft removal in selected patients facilitates open conversion and appears durable. Acute conversion is associated with increased mortality.

The Relationship Between Volume and Outcome Following Elective Open Repair of Abdominal Aortic Aneurysms (AAA) in 131 German Hospitals

Several studies indicate that high-volume hospitals have better results in open repair of unruptured abdominal aortic aneurysms (AAA). Up to now no studies had addressed this question in German hospitals. Post-hoc-analysis from a prospective physician-led registry. Since 1999, the German Society for Vascular Surgery has conducted a prospective registry for open and endovascular repair of AAAs. This study includes 131 hospitals who conducted n=10163 elective open repairs for unruptured AAA between 1999 to 2004. All perioperative variables including annual volume as a continuous variable were analysed in a step-wise logistic regression model. In order to define a threshold annual volume an additional logistic regression analysis was performed by use of annual volume groups (0-9, 10-19, 20-29, 30-39, 40-49, 50 or more). The relationship between annual volume and further outcome parameters (length of procedure, blood transfusion, length of stay) were also analyzed. The overall mortality rate was 3.2%. The stepwise logistic regression model identified the following predictors of an increased perioperative mortality: age (OR 1.084, 95% CI 1.066-1.102), AAA diameter (OR 1.008, 95% CI 1.001-1.016), length of procedure (OR 1.008, 95% CI 1.006-1.009), ASA-Score (OR 2.636, 95% CI 2.129-3.264), suprarenal clamping (OR 1.447, 95% CI 1.008-2,078), blood transfusion (OR 1.786, 95% CI 1.268-2.514). Annual volume was moderately predictive (OR 1.003, 95% CI 1-1.006) but failed to reach statistical significance (p=0.07). The analysis of volume groups identified a significantly higher risk for hospitals with an annual volume of 1-9 AAA-repairs by comparison to hospitals with an annual volume of 50 or more AAA-repairs (OR 1.903, 95% CI 1.124-3.222). Operations at low volume hospitals were also longer (p<0.001), with an extended postoperative stay (p<0.001) and a higher transfusion rate (p<0.001). Patient's age, ASA classification, AAA diameter, length of procedure, suprarenal clamping and blood transfusion are predictive variables for an increased perioperative mortality in elective open AAA repair. Mortality is also increased by a low annual volume. Further studies are needed to examine whether these data are applicable to all German hospitals.

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

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). 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. 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. 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.

External validation of the Glasgow Aneurysm Score to predict outcome in elective open abdominal aortic aneurysm repair

Selecting patients based on their risk profiles could improve the outcome after elective surgery of an abdominal aortic aneurysm (AAA). The Glasgow Aneurysm Score (GAS) is a scoring system developed to determine such risk profiles. In other settings, the GAS has proved to have a predictive value for the postoperative outcome. The aim of this study was to investigate whether the GAS was also valid for the patients in our hospital and to examine risk factors with a possible predictive value for postoperative mortality and morbidity. We performed a retrospective cohort study in a university hospital. The medical records of 229 patients who underwent open elective repair for an AAA in the period 1994 to 2003 were retrospectively analyzed to assess the GAS and to determine which of the examined risk factors had a predictive value for the prognosis. Five patients (2.2%) died after surgery and 30 (13.1%) had a major complication. The GAS was predictive for postoperative death (P = .021; sensitivity, 1.00; 95% confidence interval [CI], 0.52 to 1.00; specificity, 0.67; 95% CI, 0.61 to 0.73) and also for major morbidity (P = .029; sensitivity, 0.63; 95% CI, 0.46 to 0.78; specificity, 0.70; 95% CI, 0.64 to 0.76). The positive predictive value (mortality, 0.06; morbidity, 0.24) and the positive likelihood ratio (mortality, 3.07; morbidity, 2.14) were low, however. The best cutoff value for the GAS was determined at 77. All the deceased patients (100%) and 63.3% of those who had a major complication had a risk score of >or=77. Of all examined risk factors, suprarenal clamping during surgery was predictive of in-hospital mortality (8.3%, P = .017). For major morbidity, three risk factors, all of which are components of the GAS, were predictive: age (P = .046), cardiac disease (P = .032), and renal disease (P = .041). The Glasgow Aneurysm Score has a predictive value for outcome after open elective AAA repair. Because of its relatively low positive predictive value for death and major morbidity, the GAS is of limited value in clinical decision-making for the individual high-risk patient. In some particular cases, however, the GAS can be a useful tool, especially for low-risk patients because it has good negative predictive value for this group. Suprarenal clamping was found to be a risk factor for postoperative death.

Total laparoscopic suprarenal aortic coral reef removal

Symptomatic suprarenal coral reef aortic lesions have a poor natural history and threaten visceral and lower extremity perfusion. We report our experience with total laparoscopic suprarenal aortic coral reef removal in three patients, aged 46, 48, and 52 years. Coral reef lesions were associated with aortoiliac occlusive lesions in two cases. One patient had an associated thoracic coral reef lesion. Patients underwent total laparoscopic coral reef removal combined with laparoscopic aortobifemoral bypass in two cases and open thoracic coral reef removal in one case. Postoperative courses were uneventful. All patients were alive with patent revascularization after a mean follow-up of 38 months, 29 months, and 1 month.

Management of Juxtarenal Aortic Aneurysms and Occlusive Disease With Preferential Suprarenal Clamping Via a Midline Transperitoneal Incision: Technique and Results

Management of Juxtarenal Aortic Aneurysms and Occlusive Disease With Preferential Suprarenal Clamping Via a Midline Transperitoneal Incision: Technique and Results

Prediction of Survival After 48-h of Intensive Care Following Open Surgical Repair of Ruptured Abdominal Aortic Aneurysm

Objective To identify predictive factors for 30-day mortality after 48 h of maximal treatment in intensive care unit (ICU) after repair for ruptured abdominal aortic aneurysm (RAAA). Design Retrospective study in the ICU of the university central hospital. Materials and methods Between 1999 and 2003, a total of 197 patients were admitted to emergency unit due to RAAA, and 185 of them underwent open surgical repair. A total of 138 patients survived at least 48-h and were included in a study to identify factors predictive of 30-day mortality by logistic regression analysis. Results Thirty-day mortality of all RAAA patients was 46% (87/197) whereas the 30-day mortality for those alive at 48 h was 22% (31/138). Forward stepwise multivariate logistic regression analysis revealed that only organ dysfunction by SOFA score (sequential organ failure assessment) at 48-h, preoperative Glasgow Aneurysm Score, and supra-renal clamping in operation were independent predictors of death. Conclusions Degree of organ dysfunction by SOFA score was the best predictor of 30-day mortality in RAAA patients alive at 48-h after open surgical repair.

Exogenous nitric oxide modulates the systemic inflammatory response and improves kidney function after risk-situation abdominal aortic surgery

Renal impairment is a very frequent complication of aortic surgery requiring prolonged suprarenal clamping, especially if it is associated with previous hemorrhage. The aim of this study was to assess the beneficial effect of the administration of a nitric oxide (NO) donor on renal function through a modulation of the systemic inflammatory response in a model of abdominal aortic surgery. Twenty-five minipigs were divided into five groups. Under anesthesia, the animals were subjected to suprarenal aortic-iliac clamping (for 30 minutes) and bypass with a Dacron-collagen prosthetic graft impregnated in rifampicin, with or without associated hemorrhage (40% of total blood volume). Prophylaxis with cefazolin was implemented. The five groups were (1) the sham group (only aortic dissection), (2) the clamping and bypass (C) group, (3) hemorrhage preclamping and bypass (H+C) group, (4) the same as group C but with the administration of the NO donor molsidomine (4 mg/kg intravenously) (C+NO group), (5) the same as the H+C group but with the administration of the NO donor molsidomine (4 mg/kg intravenously) (H+C+NO group). The following were determined: (1) kidney function (serum creatinine), (2) serum cytokines (tumor necrosis factor alpha [TNF-alpha] and interleukin-10 [IL-10]); (3) neutrophil infiltration (myeloperoxidase [MPO]) in the kidney, (4) oxygen free radicals (superoxide anion [SOA] and superoxide dismutase [SOD]) in the kidney, (5) serum nitrites, (6) soluble and kidney tissue cell adhesion molecule (soluble intercellular adhesion molecule-1 [sICAM-1], soluble vascular cell adhesion molecule-1 [sVCAM-1], intercellular adhesion molecule-1 [ICAM-1], and vascular cell adhesion molecule-1 [VCAM-1]), (7) inducible nitric oxide synthase (iNOS) in the kidney, and (8) nuclear factor-kappaB (NF-kappaB) in the kidney. Determinations were made during ischemia at 15 minutes post-reperfusion; at 24, 48, and 72 hours; and on day 7. The different insults used in the experimental model led to deterioration in kidney function and an increase in the systemic (and renal) inflammatory response at all levels investigated. Treatment with an NO donor, both with and without associated hemorrhage, reduced the inflammatory response at the systemic (TNF-alpha and IL-10) and kidney (MPO, SOA, and SOD) levels, normalizing kidney function. Likewise, exogenous administration of NO improved the excessive production of NO (nitrites) via iNOS. This was also reflected in a reduction in CAMs and of NF-kappaB expression. The hypotension induced by molsidomine was transitory and did not elicit hemodynamic repercussions. In our experimental model, prophylactic treatment with the NO donor molsidomine regulates the systemic inflammatory response and minimizes damage at the kidney level. Clinical Relevance The importance of this article resides in the fact that an experimental study that clarifies the effect of the donors of NO under circumstances as similar as possible to those of the human clinic, such as aortic surgery under hypovolemic shock (ruptured aortic aneurysm) have been little studied, most of these studies being performed in rodents without bypass. Using a model with one or two simultaneous insults (aortic clamping with/without previous hemorrhage) that is very similar to the human clinical situation (abdominal aortic rupture), we confirm the findings of previous work related to the beneficial effects of NO donors.

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.

Delayed open conversion following endovascular aortoiliac aneurysm repair: partial (or complete) endograft preservation as a useful adjunct

The purpose of this study was to review our experience with delayed open conversion (>30 days) following endovascular aortoiliac aneurysm repair (EVAR) and to introduce the concept and advantages of endograft retention in this setting. From January 1992 to January 2003, a total of 386 EVARs using a variety of endografts were successfully deployed. Eleven (2.8%) patients required delayed conversion to open repair at an average of 30 months (range, 10-64). Data from all patients undergoing both EVAR and open conversion were prospectively collected. EVARs were performed using grafts made by Talent (4), Vanguard (2,) AneuRx (1), and Surgeon (4). Conversion to open repair (9 transabdominal, 1 retroperitoneal, 1 transabdominal plus thoracotomy) was performed for aneurysm rupture in 7 patients (4 type 1 endoleak, 2 type 2 endoleak, 1 aortoenteric fistula) and aneurysm enlargement in 4 patients (1 type 1 endoleak, 1 type 2 endoleak, 1 type 3 endoleak, 1 endotension). Patients with aneurysm rupture were treated on an emergent basis. Complete removal of the endograft with supraceliac cross-clamping was performed in two cases. One patient (rupture) did not survive the operation, and one patient (aortoenteric fistula) died 2 weeks postoperatively. In the remaining nine cases, the endograft was either completely (1) or partially (6) removed, or left in situ (2). Supraceliac balloon control (2), supraceliac clamping (1), suprarenal clamping (1), or infrarenal clamping (5) was used in these cases. All nine of these patients survived the operation. In one procedure in which the endograft was left intact (endotension), repair was accomplished by exposing the endograft and by placing a standard tube graft over it as a sleeve. In the second procedure in which the graft was left in situ (rupture), the graft was well incorporated, and bleeding lumbar arteries were oversewn and the sac was closed tightly over the endograft. In the remaining 7 cases, the endograft was transected and the proximal portion only (6) or the proximal and distal portions (1) were excised. All surviving patients continue to do well and remain without complications associated with the endograft remnant at a mean follow-up of 22 months (range, 3-56) from the time of open conversion and 46 months (range, 10-73) from the time of original EVAR. Open repair in the setting of a long-standing endograft offers several unique technical challenges but can be successfully accomplished in most patients. Preservation of all or part of the endograft is possible in many patients. This technique simplifies the operative approach and is preferred over complete endograft removal if possible.

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.

Clampaje suprarrenal y evolución de la función renal en los aneurismas yuxtarrenales

The juxtarenal aneurysm and the suprarenal cross-clamp, have been related with poor results in postoperatory morbidity. Some reports involve the renal function deterioration in this fact. The aim of this work is to determine the postoperative renal function impairment during the suprarenal cross-clamp in aortic abdominal aneurysm repair. Within 1992-2001 period, 374 abdominal aortic aneurysms, had been repaired in elected way. Juxtarenal type was encounter in 53 patients and underwent a suprarenal clamping. Risk factors and renal function data were analyzed. No specific renal preservation method was used. Sequenced postoperative serum creatinine levels were collected. Timing of suprarenal clamping was carefully annotate. Mortality rate was 5.6% (3). Eight patients (15.1%) developed postoperative renal insufficiency. The suprarenal mean time was 30.2 min (15-75 min). The statistic analysis show that preoperative renal insufficiency is determinant, in the increase of values of postoperative serum creatinine (p = 0.018), in spite of crossclamp timing. Likewise, in the patients with preoperative normal renal function, the rise of creatinine level, become significant at 35 minutes of suprarenal cross-clamping (p = 0.02). No statistic differences were encountered between discharge creatinine levels and preoperatory baseline. Previous isquemic cardiopathy was the only morbidity predictor. In patients with normal renal function, no specific renal function preservation method is necessary below 35 minutes of suprarenal cross-clamp. In uremic patients in which a suprarenal crossclamping is performed, an impairment in renal function is always expected. In our serie the morbidity, was depend on preoperative risk factors. Los aneurismas yuxtarrenales que requieren clampaje suprarrenal (CSR) se han asociado con una morbimortalidad mayor postoperatoria, que en algunos trabajos se ha relacionado con el deterioro de la función renal. Determinar la repercusión renal del CSR para la corrección del aneurisma de aorta abdominal (AAA). Pacientes y métodos. En el período 1992-2001, se ha intervenido electivamente a 374 pacientes con AAA. De ellos, 53 eran yuxtarrenales y requirieron un CSR. Se analizan los factores de riesgo generales y los datos de la función renal preoperatoria. No se utilizó ningún método de protección renal específico. Se midió la creatinina de forma seriada tras la operación y se relacionó con el tiempo de clampaje y la función renal previa. La mortalidad fue del 5,6% (tres). Un 15,1% (ocho) de los pacientes presentaron insuficiencia renal (IR). El tiempo de clampaje fue de 30,2 min (15-75 min). La IR previa fue determinante para la elevación de la creatinina en el postoperatorio (p = 0,018). El tiempo de clampaje, cuando fue mayor de 35 min, alcanzó significación estadística para la elevación de la creatinina (p = 0,02) en los pacientes con una función renal previa normal. En los pacientes con función renal normal, la creatinina al alta no mostró diferencias significativas con la basal. El único factor determinante en la morbimortalidad fue la cardiopatía isquémica (p = 0,02). En pacientes con función renal normal no se necesitan métodos de protección renal, si el tiempo de CSR es inferior a 35 min. En los pacientes con IR se espera un deterioro de la función renal siempre que se realice un CSR. La morbimortalidad en nuestra serie ha dependido de los factores de riesgo. Os aneurismas justarenais que requerem clampagem supra-renal (CSR) foram associados a uma maior morbilidade- mortalidade operatória, que em alguns trabalhos foi relacionada com a deterioração da função renal. Determinar a repercussão renal do CSR para a correcção do aneurisma da aorta abdominal (AAA). No período 1992-2001, foram electivamente submetidos a operação 374 AAA. Destes, 53 eram justa-renais, e requereram um CSR. Analisam-se os factores de risco gerais e os dados de função renal préoperatória. Não se utilizou qualquer método de protecção renal específico. Mediram-se as creatininas seriadas pós-operatórias, e relacionaram- se com o tempo de clampagem e com a função renal prévia. A mortalidade foi de 5,6% (três). 15,1% (oito) dos doentes apresentaram insuficiência renal (IR). O tempo de clampagem foi de 30,2 min. (15-75 min). A IR prévia foi determinante para a avaliação da creatinina e no pós-operatório (p = 0,018). O tempo de clampagem, quando foi maior que 35 min, alcançou significado estatístico para a elevação da creatinina (p = 0,02), nos doentes com função renal prévia normal. Nos doentes com função renal normal, a creatinina à alta não mostrou diferenças significativas com a basal. O único factor determinante na morbilidade e mortalidade foi a cardiopatia isquémica (p = 0,02). Em doentes com função renal normal, não são necessários módulos de protecção renal, se o CSR for inferior a 35 min. Nos doentes com IR espera-se uma deterioração da função renal sempre que se realize um CSR. A morbilidade e mortalidade na nossa série tem dependido dos factores de risco.

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. (J Vasc Surg 2002;36:13-8.)

Ruptured abdominal aortic aneurysm and quality of life.

This study was undertaken to examine the community hospital experience in managing ruptured abdominal aortic aneurysm, and to assess the quality of life in survivors of the abdominal aortic aneurysm procedure. Study parameters included a retrospective chart review with prospective follow-up at a 369-bed, university-affiliated, community teaching hospital. Eighty-one consecutive patients undergoing surgery for ruptured abdominal aortic aneurysm between 1991 and 2000 were included. Main outcome measures included mortality and quality of life, as assessed by the SF-36 health survey. The overall perioperative mortality rate was 34.6%, significantly less (p < 0.005) than the 50% mortality rate reported in the literature. Predictor variables significantly related to mortality were age (p < 0.002), preoperative creatinine (p < 0.026), use of suprarenal clamp (p < 0.0001), acute renal failure (p < 0.0001), myocardial infarction (p < 0.0001), respiratory failure (p < 0.0001), and tobacco use (p < 0.05). Multiple regression analysis found that three predictor variables--myocardial infarction, respiratory failure, and use of a suprarenal clamp--predicted 25% of the variability in mortality (p < 0.0001). The quality-of-life analyses showed that the majority of the patients for whom follow-up data could be obtained (n = 26), reported the same or better quality of life compared to SF-36 norms for age-matched individuals. Results from this community hospital sample suggest that ruptured abdominal aortic aneurysm repair can be accomplished in this setting with an acceptable survival rate, and subsequent quality of life that meets or exceeds that of an age-matched sample.

Hand-Assisted Laparoscopic Abdominal Aortic Aneurysm Repair

Hand-assisted laparoscopic aneurysm resection enables the surgeon to use his tactile senses while performing a laparoscopic aneurysm repair. Even more complex procedures that involve suprarenal clamping of the aorta can be performed by using this laparoscopically assisted approach. Twenty-nine laparoscopic patients were compared with a control group of 19 patients who were operated on conventionally. Transperitoneal hand-assisted laparoscopic aneurysm resection with a tube graft or a bifurcated graft was performed. The anastomosis was sutured with conventional instruments using the mini-incision as an access. The time for laparoscopy did not exceed 40 minutes. The incidence of complications did not vary between groups. The mean operating time was 135 minutes in the conventional group versus 180 minutes in the minimal invasive group. Intensive care stay and postoperative hospital stay were significantly shorter after the laparoscopic procedure. An oral diet was resumed significantly earlier, and the time until complete recovery was shortened in the miniaccess group. Hand-assisted laparoscopic aneurysm resection can be performed safely with operating times almost as expeditiously as in open surgery. Because it can be offered to the majority of patients with aortic disease, the technique described has distinct advantages over a total laparoscopic approach and a less steep learning curve.

Suprarenal Aortic Cross-Clamping in Elective Abdominal Aortic Aneurysm Surgery

Introduction: this retrospective study was undertaken to evaluate whether suprarenal aortic cross-clamping increased the perioperative mortality and morbidity as compared to infrarenal clamping, in order to create the rationale for a more extensive application of this apparently more traumatic manoeuvre. Materials and methods: in a series of 734 elective aortic substitutions for abdominal aneurysm (AA), performed consecutively from January 1992 to June 1999, aortic cross-clamping was performed at a suprarenal level in 56 juxtarenal aneurysms, i.e. aneurysms extending to the lower edge of the renal arteries (8%, Group 1), and at an infrarenal level in 634 subrenal aneurysms (92%, Group 2). When analysing preoperative data, the diameter of aneurysms was larger in Group 1 than in Group 2 (p<0.005). No significant differences were found between the two groups as regards age, sex, postinfarction cardiomyopathy, chronic obstructive pulmonary disease, chronic renal insufficiency and ASA classification of operative risks. Results: the average time of renal exclusion in the juxtarenal aneurysms was 20 min (range 12–35 min). There is no difference between the two groups as regards the time of aortic clamping (mean 50 vs. 60 min) or the need for homologous blood transfusion (7% vs. 11% of patients). Perioperative (30 days) mortality did not differ: 3.6% vs. 1.9% (n.s.); nor did the incidence of acute myocardial infarction (3.6% vs. 2.3%). Renal function deteriorated in 8 (14%) vs. 0 (0%) (p<0.001) and 1 patient (2%) required permanent dialysis, as compared to 0% in Group 2. The incidence of ischaemic colitis was also significantly higher in Group 1 (7%) than in Group 2 (2%, p<0.01). Conclusion: this data shows that suprarenal clamping, which is necessary for the radical treatment of juxtarenal aortic aneurysms, can be performed with a low risk.

Postoperative renal function after an abdominal aortic aneurysm repair requiring a suprarenal aortic cross-clamp.

We describe herein the postoperative renal functions of patients who required a suprarenal aortic cross-clamp during abdominal aortic surgery. Seven patients required a unilateral suprarenal aortic cross-clamp (group A) and six patients required a bilateral suprarenal clamp (group B). Eighty-three patients who required an infrarenal aortic clamp were assigned to group C. Renal hypothermia with renal perfusion or topical cooling during suprarenal clamp was not performed. No hospital deaths were encountered. In group B, the postoperative creatinine and blood urea nitrogen (BUN) levels remained statistically significantly higher than that of group C until the seventh postoperative day. The postoperative renal dysfunction (serum creatinine level >2.0 mg/dl) was 28.6% in group A and 50% in group B, while it was only 8.4% in group C, although no patient required either temporary or permanent hemodialysis. The postoperative peak BUN over 30 min suprarenal clamp was significantly higher than that within 30 min. In summary, the postoperative renal function was impaired after an extended bilateral suprarenal clamp. These findings suggest that if prolonged renal ischemia is thus expected, then renal preservation should be considered.

Factors maintaining a pH gradient within the kidney: Role of the vasculature architecture

The architecture of the vasa rectae produces significant oxygen (O2) "shunting" and marked decreases in renal medullary pO2 values. We hypothesized that carbon dioxide (CO2) trapping and increases in medullary pCO2 along with decreases in medullary pH values should also accompany this O2 shunting. We developed computer simulations employing a model of gas exchange through the countercurrent vasculature that predicted trapping of CO2 along with O2 shunting. To test the validity of this model directly, medullary pH was measured by using needle electrodes in the in situ kidney before and after the administration of mannitol or furosemide, or by decreasing blood flow with a transient decrease of renal perfusion pressure with a suprarenal clamp. Data are expressed as mean +/- SD. Medullary pH was lower than cortical pH (7.20 +/- 0.09 vs. 7.39 +/- 0.08, P < 0.01). Mannitol caused a decrease in medullary pH to 7.02 +/- 0.07 (P < 0.01), whereas furosemide increased medullary pH to 7. 31 +/- 0.09 (P < 0.01). Brief periods of severe hypotension decreased medullary pH to 6.90 +/- 0.09 (P < 0.01). These data demonstrate that a significant pH gradient exists within the kidney parenchyma. This gradient is related to the metabolic activity of the thick ascending limb of Henle and the countercurrent vascular architecture, and may be relevant to a variety of physiological phenomena involved in volume, electrolyte, and acid-based homeostasis.