A cohort study of coagulation parameters and the use of blood products in surgery of the thoracic and thoracoabdominal aorta

OBJECTIVES: We sought to study the hemostatic profile and the use of blood products in patients undergoing thoracic and thoracoabdominal aortic aneurysm repair. METHODS: This is a cohort study comparing three groups of patients: 7 undergoing elective acute normovolemic hemodilution (ANH); 15 undergoing elective procedures without ANH (non-ANH); and 8 undergoing repair of ruptured thoracoabdominal aneurysms. A control group of 10 patients was used for comparison of preoperative hemostasis. The parameters studied were platelet concentration, partial thromboplastin time (PTT), and international normalized ratio (before and after surgery), packed red blood cells, fresh frozen plasma, platelets, cryoprecipitates, donor exposure, and use of desmopressin and epsilon-aminocaproic acid. Analysis of variance and multiple stepwise regression analysis were used. RESULTS: Before operation the patients with aneurysms had PTTs prolonged compared with control subjects (P <.05). After operation the ANH group had higher platelet counts than the ruptured group (P =.001) and higher platelet counts (P =.05) and lower PTTs (P =.001) than the non-ANH group. The ANH group was transfused fewer platelets than the non-ANH group (P =.001) and less of every blood product than the ruptured group (P =.05); statistically significant differences were not observed for packed red blood cells, fresh frozen plasma, or platelets. The ANH group was exposed to an average of 65 donors fewer than the ruptured group (P <.001) and 34 fewer than the non-ANH group (P <.05). These differences could not be explained by baseline coagulation status or by the intraoperative use of desmopressin or epsilon-aminocaproic acid. CONCLUSIONS: The coagulation abnormality identified before surgery is that of higher PTT values, suggesting a disturbance of the extrinsic coagulation pathway. Blood losses, donor exposure, and platelet use were highest in the ruptured group and lowest in the ANH group. After surgery the ruptured group exhibited the worst coagulation parameters, and the ANH group exhibited the best with higher platelet count and lower PTT values than the other groups. The ANH technique appears to be an useful adjunct in the anesthetic management of these patients.     

The Impact of Introducing an Autologous Intraoperative Transfusion Device to a Community Hospital

The purpose of this study was to determine the benefits and disadvantages of transfusing autologous blood during abdominal aortic aneurysm (AAA) surgery at a district general hospital with an intraoperative autologous transfusion device (Haemoccel ABT 350). In this retrospective study, 128 patients underwent abdominal aortic aneurysm repair between 1992 and 1999 by a single vascular surgeon. Ninety-three patients (60 autologous and 33 allogeneic) had elective AAA repair (group A) and 25 patients (4 autologous and 21 allogeneic) had emergency AAA repair (group B). Nine group A patients (7.6%) received their own salvaged blood and no other allogeneic blood. Although the mean estimated blood loss was higher in the autologous group of patients (NS), the intraoperative autologous transfusion device did not significantly reduce allogeneic blood usage in patients who had autologous transfusion in both elective and emergency groups. There was no difference in postoperative hemoglobin and hematocrit, ICU stay or hospital stay. In this study, red cell salvage was significantly more expensive than blood bank usage (p < 0.0001), yet it did not significantly reduce the needs of allogeneic blood. We concluded that the intraoperative autologous transfusion device is underused, not cost-effective and requires formulation of local guidelines.     

Haemodilutional effect of standard fluid management limits the effectiveness of acute normovolaemic haemodilution in AAA surgery--results of a pilot trial.

OBJECTIVE: To evaluate the impact of standard fluid management on the effectiveness of ANH as a blood conservation method in elective open AAA repair. DESIGN: Prospective randomised controlled study. METHODS: Thirty-four patients undergoing elective AAA repair were randomised to have ANH (16) or act as controls (18). Intra-operative cell salvage was permitted in both groups. Haemoglobin (Hb) concentrations were determined at variable intervals peri-operatively. Blood loss and the use of heterologous blood were recorded. RESULTS: The pre- and post-operative Hb concentrations, surgical blood loss and the use of cell salvage were similar in both groups. Hb concentration (median, range) decreased significantly from pre-operative to aortic clamping (with blood loss <100 ml) in ANH patients from 8.8 (7.5-10.2) to 5.7 (4.2-6.6)mmol/l following ANH but also in controls from 8.6 (7.5-9.7) to 7.0 (4.5-9.0)mmol/l due to fluid infusion (P<0.01 for every comparison). Bank blood requirements were similar: median 2 units in ANH and 2.5 units in control patients (P=0.68). CONCLUSIONS: Large volumes of fluids infused during AAA repair already conserve blood by the mechanism of hypervolaemic haemodilution. When cell salvage is used with standard fluid management during AAA repair, additional ANH is ineffective in saving blood.     

The effect of acute normovolaemic haemodilution on the inflammatory response and clinical outcome in abdominal aortic aneurysm repair--results of a pilot trial.

OBJECTIVES: To determine the effect of acute normovolaemic haemodilution (ANH) on the inflammatory response and clinical outcome in elective open abdominal aortic aneurysm (AAA) repair. DESIGN: Randomised controlled clinical trial. METHODS: Thirty-six patients were randomised to undergo ANH or act as controls. Cell salvage was permitted in both groups. Heterologous blood was transfused according to pre-determined triggers. Outcome measures were markers of the systemic inflammatory response in serum and urine observed at multiple time points, and clinical recovery. RESULTS: Median 890 (range 670-1620) ml of blood was removed at ANH in 16 patients. There were no differences in peri-operative changes in neutrophil count ( P = 0.13), serum C-reactive protein ( P = 0.38), interleukin-6 ( P = 0.50), total antioxidant capacity ( P = 0.73), urinary secretion of albumin ( P = 0.97) or retinol binding protein ( P = 0.41). There were no differences in the mortality and morbidity rates, systemic inflammatory response syndrome, ITU or hospital stay. CONCLUSIONS: ANH, when used in combination with cell salvage, made no impact on systemic inflammatory response and clinical outcome when compared to cell salvage alone after AAA repair. ANH cannot be recommended for routine use in patients undergoing abdominal aortic aneurysm surgery when cell salvage is available.     

Blood loss and transfusion in elective abdominal aortic aneurysm surgery

BACKGROUND: Intraoperative blood loss and transfusion are known determinants of mortality and morbidity of elective abdominal aortic aneurysm (AAA) repair. The present study analysed the pattern of blood loss and transfusion and evaluated the risk factors of blood loss during open repair of infrarenal AAA. METHODS: Blood loss, transfusion and fluid replacement during elective open repair operation for patients with infrarenal AAA were correlated to demographic data, operative findings and procedural information. RESULTS: A total of 129 patients with a mean age of 71 years was analysed. The mean blood loss was 1000 +/- 887 mL (200-6000 mL). Blood transfusion, with a mean transfusion volume of 400 +/- 591 mL (0-3000 mL), was required in 46% of patients. Univariate analysis showed that bodyweight, renal impairment, low haemoglobin and platelet counts, iliac artery involvement, large aneurysm, bifurcated graft, large graft diameter, prolonged aortic clamp time and long operation time were associated with a higher blood loss. A haemoglobin level of <10.5 g/dL (relative risk (RR): 4.6), platelet count <130 x 10(9)/L (RR: 3.9), aortic clamp time >50 min (RR: 15), total operation time >200 min (RR: 11) and type of graft (RR: 3.5) were identified as independent determinants of blood loss on multivariate analysis. CONCLUSION: Intraoperative blood loss in elective infrarenal aneurysm surgery is influenced by patients' haematological parameters, distal involvement of aneurysm and degree of difficulty of operation.     

Eliminating homologous blood transfusions during abdominal aortic aneurysm repair

In order to eliminate homologous blood transfusions during abdominal aortic aneurysm (AAA) repair, increased usage of autologous predonation and intraoperative salvage is required. To determine what quantity of predonated blood is necessary to completely avoid the use of homologous blood, we reviewed the transfusion histories of 100 consecutive patients undergoing elective AAA repairs. A total of 445 units of blood were transfused, and the number of units required was directly proportional to the size of the aneurysm. One hundred sixty-six units of blood (37%) were homologous, and 279 units (63%) were autologous. Of the autologous units, 255 (91%) were from intraoperative salvage and 24 (9%) were predonated. Stratification of transfusions by size revealed that for aneurysms less than or equal to 7 cm, 132 units of homologous and 21 units of predonated blood were transfused (1.55 units per patient and 0.25 units per patient, respectively). For aneurysms greater than 7 cm, 34 units of homologous and 3 units of predonated blood were used (2.3 units per patient and 0.2 units per patient, respectively). From these data, it is concluded that predonation before surgery of a minimum of 2 units for patients with smaller aneurysms and 3 units for patients with larger aneurysms, combined with intraoperative salvage, should eliminate the need for any homologous blood transfusions associated with elective AAA repair.     

Impact of Red Cell Salvage on Transfusion Requirements during Elective Abdominal Aortic Aneurysm Repair

Elective abdominal aortic aneurysm (AAA) surgery may result in substantial blood loss. Concerns regarding the safety, availability, and acceptability of homologous blood have led to initiatives toward reducing transfusion requirements at the time of aneurysm repair. This study was designed to determine if the routine use of intraoperative red cell salvage and autotransfusion resulted in a reduction in homologous transfusion at our institution. A retrospective review of elective AAA repairs in the years 1987, 1992, and 1997 was carried out. Demographic data, operative details, blood loss, hemoglobin levels, red cell salvage and return volumes, and transfusion requirements were recorded and compared across the study years. From this study we conclude that routine use of red cell salvage and autotransfusion is an effective means for reducing transfusion requirements in elective AAA repair.     

Acute normovolemic hemodilution and intraoperative cell salvage in aortic surgery

OBJECTIVE: The objective of this study was to report current transfusion requirements and outcomes in patients undergoing elective aortic surgery with autologous transfusion. METHODS: This was a retrospective review of transfusion practice in infrarenal aortic surgery in a tertiary vascular unit with a longstanding interest in autologous transfusion. One hundred and ten consecutive patients underwent infrarenal aortic surgery with a combination of acute normovolemic hemodilution (ANH) and intraoperative cell salvage (ICS). All patients underwent hemodilution to a target hemoglobin concentration of 11 g/dL and underwent ICS with a centrifugal device. RESULTS: Median blood loss was 1140 mL (interquartile range [IQR], 683 to 1609 mL) in 78 aneurysm repairs and 775 mL (IQR, 400 to 1225 mL) in 32 aortobifemoral bypasses for occlusive disease (P =.02), resulting in a median salvaged red cell volume of 403 mL (IQR, 256 to 563 mL) for aneurysm repairs and 250 mL (IQR, 200 to 290 mL) in bypass surgery (P =.001). Thirty-six patients (33%) needed transfusion of stored blood, for a total of 115 units, with just four patients needing more than five units. The mortality rate was 8% (9/110). With multivariate analysis, low hemoglobin level (P =.006) and low platelet count (P =.023) were associated with stored blood transfusion. CONCLUSION: Blood loss is too small to justify ICS in surgery for occlusive disease; ANH alone may be a suitable strategy. With appropriate experience, the combination of ANH and ICS may render crossmatching unnecessary, even in aortic aneurysm surgery.     

A randomized trial of intraoperative autotransfusion during aortic surgery

Purpose: The net benefit of routine intraoperative autotransfusion (IAT) in patients undergoing elective infrarenal aortic surgery was studied. Methods: One hundred patients undergoing abdominal aortic aneurysm (AAA) repair (n = 50) or aortofemoral bypass (AFB) for occlusive disease (n = 50) were randomized to IAT and control groups. This experience accounted for 58% of patients undergoing aortic surgery during the 16-month study period. Results: IAT and control groups were balanced for preoperative demographics, disease (50:50 split of AFB:AAA in each group), and risk factors. There were no significant differences between patients randomized to IAT and control patients in estimated blood loss (EBL), allogeneic blood transfusion (units administered intraoperatively, postoperatively, and total), proportion of patients not receiving allogeneic blood (34% of patients randomized to IAT and 28% of control patients), postoperative hemoglobin/hematocrit levels, and complications. IAT did not reduce allogeneic blood transfusion among all patients undergoing aortic surgery nor in any subgroups that might be more likely to benefit, such as those undergoing AAA repair, those with 1000 mL or more EBL, and those receiving larger volumes of IAT-processed blood. Conclusion: We could find no net benefit of IAT in patients undergoing elective, infrarenal aortic surgery. (J Vasc Surg 1999;29:22-31.)     

An audit of emergency abdominal aortic aneurysm repair to establish the necessity for an emergency vascular surgical rota.

Mortality for emergency abdominal aortic aneurysm (AAA) repair remains high but results of specialist vascular surgeons are superior to those of general surgeons. A retrospective audit was performed on all patients undergoing emergency AAA repair over 53 months at one hospital to determine the necessity for a vascular specialist on-call rota. Patients were stratified into two groups, those treated by specialist vascular surgeons and those treated by general surgeons. There were 37 patients in the vascular surgeon group and 36 in the general surgeon group. There was no significant difference between the two groups when age, sex distribution, APACHE II score on admission, pre-operative delay and type of rupture were considered. The average operating time was 114.7 min in the vascular surgeon group and 111.9 min in the general surgeon group. Total blood transfusion requirements, and postoperative duration of ventilation, inotrope therapy and intensive treatment unit stay were similar in the two groups. Intra-operative, 30-day and cumulative hospital mortalities were 10.8% versus 8.3%, 32.4% versus 38.9% and 40.5% versus 38.9% in the vascular surgeon and general surgeon groups, respectively. The mortality figures compare favourably with other published series. As the results of the two groups were similar, there is currently no need for vascular surgeons to be routinely available for acute AAA surgery at our hospital.     

Randomized, multicentre, double-blind, placebo-controlled trial of the use of aprotinin in the repair of ruptured abdominal aortic aneurysm. On behalf of the Joint Vascular Research Group

BACKGROUND: The use of aprotinin in cardiac surgery reduces blood transfusion requirements. The aim of this trial was to see whether the same benefit applies in the repair of ruptured abdominal aortic aneurysm (AAA). METHODS: In this prospective, randomized trial, nine centres with local ethics committee approval recruited 77 patients with a ruptured AAA. A bolus of aprotinin 2 x 106 units, followed by an infusion of 0.5 x 106 units every 30 min, was administered to 38 patients, and 39 received a placebo infusion. The quantity of blood products transfused during surgery and in the first 12 h after operation was noted, along with the incidence of complications, mortality rates and length of hospital stay. RESULTS: Seventeen of the 38 patients who received aprotinin and 17 of the 39 given placebo died within 30 days (overall mortality rate 44 per cent). The median amount of blood given to the aprotinin group after operation was 1 (range 0-14) unit, while for the placebo group it was 3 (range 0-13) units (P = 0.02). However, the difference in the total number of units of blood transfused did not reach significance (10 (range 2-29) versus 14 (range 4-38) units respectively). CONCLUSION: The use of high-dose aprotinin during the repair of a ruptured AAA reduced blood transfusion requirements in the first 12 h after operation, but had no significant effect on the overall blood transfusion requirement.     

Beneficial effect of acute normovolemic hemodilution in cardiovascular surgery

OBJECTIVE: The efficacy of acute normovolemic hemodilution (ANH) in avoiding homologous blood transfusion (HBT) during cardiovascular surgery remains controversial. Our objective was to evaluate the impact of ANH on blood transfusion requirements during open cardiovascular surgery using cardiopulmonary bypass (CPB). METHODS: We retrospectively reviewed 243 patients who had undergone open cardiac or thoracic aortic surgery using CPB between September 2001 and July 2003 in our department. ANH was performed when the hematocrit was over 35% and the patient was hemodynamically stable. Risk factors were selected in accordance with the Japanese Adult Cardiovascular Surgery Database and analyzed to determine their effect on perioperative HBT requirement. RESULTS: Of the 243 patients, 64 (26%) underwent preoperative autologous blood donation and 62 (26%) ANH. HBT was required in 62% of patients (150/243) overall, in 32% (20/62) of ANH patients, and in 76% (130/171) of non-ANH patients. Multivariate stepwise logistic regression analysis revealed that preoperative or pre-donation hemoglobin value (p < 0.001), duration of surgery (p = 0.001), intraoperative minimum rectal temperature (p = 0.001), age (p = 0.002), need for emergency surgery (p = 0.003), amount of ANH (p = 0.018), blood loss (p = 0.033) and amount of preoperative autologous blood donation (p = 0.042) were independent predictors of the need for perioperative HBT. CONCLUSIONS: Our data showed that open cardiovascular surgery using CPB continues to pose a high risk of HBT, but that ANH is an effective means of reducing this risk in those patients undergoing these operations.     

Effectiveness of acute normovolemic hemodilution to minimize allogeneic blood transfusion in major liver resections

BACKGROUND: Liver resection is a major operation for which, even with the improvements in surgical and anesthetic techniques, the reported rate of blood transfusion was rarely less than 30%. About 60% of transfused patients require only 1 or 2 units of blood, a blood requirement that may be accommodated by the use of acute normovolemic hemodilution (ANH). METHODS: The efficacy, hemodynamic effects, and safety of ANH were investigated in a randomized, active-control study in patients with American Society of Anesthesiologists status I-II who were undergoing major liver resection with fentanyl-nitrous oxide-isoflurane anesthesia. Patients were randomized to the ANH (n = 39) or control group (n = 39). Patients in the ANH group underwent hemodilution to a target hematocrit of 24%. The indication for blood transfusion was standardized. In both groups transfusion was started at a hematocrit of 20%. The primary efficacy endpoint was the avoidance of allogeneic blood transfusion in the intraoperative period and first 72 h after surgery. Various laboratory and hemodynamic parameters as well as postoperative morbidity were monitored to define the safety of ANH in this patient population. RESULTS: During the perioperative period, 14 control patients (36%) received at least one unit of allogeneic blood compared with 4 patients (10%) in the ANH group ( < 0.05). The hemodilution process was not associated with significant changes in patients' hemodynamics. Morbidity was similar between the control and the ANH groups. Postoperative hematocrit levels and biochemical liver, renal, and standard coagulation test results were similar in both groups. CONCLUSIONS: Acute normovolemic hemodilution in patients with American Society of Anesthesiologists status I-II undergoing major liver resection may allow a significant number of patients to avoid exposure to allogeneic blood.     

Usefulness of one-stage coronary artery bypass grafting on the beating heart and abdominal aortic aneurysm repair.

Abdominal aortic aneurysm (AAA) is commonly associated with coronary artery disease (CAD). Simultaneous coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) under cardiac arrest and AAA repair may be considerably invasive. Recently CABG under the beating heart without CPB has been reported as a less invasive method. We report the combined operation of CABG on a beating heart and AAA repair for AAA patients with CAD, and compare it with a separate operation. A retrospective review of the records of consecutive patients who underwent elective combined procedure or single operation for CABG on a beating heart and/or repair of the AAA between May 1999 and October 2001 was carried out. Ten patients underwent combined procedures. A single operation, CABG on a beating heart or repair of AAA, were performed in 27 or 19 patients. There were no significant differences with regard to intraoperative blood loss, transfusion and postoperative intubation time among the three groups. There was no operative mortality for any of the three groups. All cases were discharged without severe complications and with patent coronary bypass grafts. There was a decrease in mean total hospital costs for the combined operation group compared with the CABG group plus AAA repair group (3.34 million versus 5.87 million yen). Combined CABG on a beating heart and AAA repair on a one-step approach appears to be a safe and useful therapeutic strategy for AAA patients with CAD.     

Endovascular repair of ruptured abdominal aortic aneurysm--a challenge to open repair? Results of a single centre experience in 20 patients.

INTRODUCTION: The mortality from ruptured abdominal aortic aneurysm (AAA) remains in the region of 50% despite advances in critical care. Endovascular repair of AAA has been shown to be associated with reduced physiological stress in the elective setting. It is hypothesised that the reduced physiological stress associated with EVAR may improve the outcome in patients with ruptured AAA. METHODS: A feasibility study of endovascular repair of ruptured AAA was undertaken at the University Hospital, Nottingham, U.K. between 1994 and 2000. Patients admitted with ruptured AAA were assessed by a team familiar with endovascular techniques for elective repair of AAA. After giving informed consent patients underwent spiral computed tomographic angiography (CTA) in the majority of cases. Patients were then transferred to the operating theatre for EVAR. RESULTS: Twenty patients underwent repair of ruptured AAA. Of these 20 patients, seven were referred from another hospital. Eight patients were considered unfit for open repair. The median duration of procedure was 180 min (range 120-480) and median blood loss was 1200 ml (range 750-2000 ml). The overall peri-operative mortality was 45%. A number of intra-operative and peri-operative procedures (both open and endovascular) were required to ensure aneurysm exclusion and to deal with the complications of endovascular surgery. CONCLUSIONS: Ruptured AAA remains a particularly hazardous condition to treat. There are a number of advantages of EVAR in this condition. A number of the problems early in the experience of EVAR have been addressed, but further experience is required to demonstrate its efficacy when compared with open repair.     

Endovascular Repair of Ruptured Abdominal Aortic Aneurysm – a Challenge to Open Repair? Results of a Single Centre Experience in 20 Patients

Introduction: the mortality from ruptured abdominal aortic aneurysm (AAA) remains in the region of 50% despite advances in critical care. Endovascular repair of AAA has been shown to be associated with reduced physiological stress in the elective setting. It is hypothesised that the reduced physiological stress associated with EVAR may improve the outcome in patients with ruptured AAA. Methods: a feasibility study of endovascular repair of ruptured AAA was undertaken at the University Hospital, Nottingham, U.K. between 1994 and 2000. Patients admitted with ruptured AAA were assessed by a team familiar with endovascular techniques for elective repair of AAA. After giving informed consent patients underwent spiral computed tomographic angiography (CTA) in the majority of cases. Patients were then transferred to the operating theatre for EVAR. Results: twenty patients underwent repair of ruptured AAA. Of these 20 patients, seven were referred from another hospital. Eight patients were considered unfit for open repair. The median duration of procedure was 180 min (range 120–480) and median blood loss was 1200 ml (range 750–2000 ml). The overall peri-operative mortality was 45%. A number of intra-operative and peri-operative procedures (both open and endovascular) were required to ensure aneurysm exclusion and to deal with the complications of endovascular surgery. Conclusions: ruptured AAA remains a particularly hazardous condition to treat. There are a number of advantages of EVAR in this condition. A number of the problems early in the experience of EVAR have been addressed, but further experience is required to demonstrate its efficacy when compared with open repair.     

Elective endovascular and open repair of abdominal aortic aneurysms in octogenarians

OBJECTIVES: Endovascular aortic aneurysm repair (EVAR) is an increasingly popular treatment option for patients with abdominal aortic aneurysms (AAA), although open repair is considered the standard by virtue of its durability. Octogenarians, as a subgroup, may stand to benefit the most by EVAR. The purpose of this study is to review operative results and durability of open AAA repair and EVAR in octogenarians. METHODS: From May 1996 to August 2006, 150 patients aged >or=80 years underwent elective repair of their infrarenal AAA. Eighty-one underwent EVAR and 69 had open repair. Demographic data, aneurysm specifics, comorbidities, operative morbidity and mortality, intensive care unit and hospital length of stay, and late outcomes were analyzed. RESULTS: In the EVAR group, 27 of 81 (33%) patients died during a mean follow-up of 25 months. In the open repair group, 34 of 69 (49%) patients died during a mean follow-up of 43 months. The median survival time for EVAR was 350 weeks (range, 145-404 weeks) compared with 317 weeks (range, 233-342 weeks) for the open repair group. A Kaplan-Meier log-rank analysis showed no difference in early or long-term survival between EVAR and open repair (P = .13). EVAR was associated with decreased blood loss, decreased length of intensive care unit and hospital stays, and a greater number of patients discharged to home. CONCLUSIONS: EVAR and open repair are comparable in safety and efficacy in octogenarians. Operative repair outcomes remain acceptable. Mid- and long-term survival are similar, indicating no survival advantage of one procedure compared with the other.     

Survival after ruptured abdominal aortic aneurysm: effect of patient, surgeon, and hospital factors

OBJECTIVE: The purpose of this study was to determine the effects of patient, surgeon, and hospital factors on survival after repair of ruptured abdominal aortic aneurysm (AAA) and to compare them with risk factors for survival after elective AAA repair. It was hypothesized that patients operated on by high-volume surgeons with subspecialty training would have better outcomes, which might argue for regionalization of AAA surgery. METHODS: In this population-based retrospective cohort study, surgeon billing and administrative data were used to identify all patients who had undergone AAA repair between April 1, 1992, and March 31, 2001, in Ontario, Canada. Demographic information was collected for each patient, as well as numerous variables related to the surgeons and hospitals. RESULTS: There were 2601 patients with ruptured AAA repair, with an average 30-day mortality rate of 40.8%. Significant independent predictors of lower survival were older age, female gender, lower patient income quintile, performance of surgery at night or on weekends, repair in larger cities, surgeons with lower annual volume of ruptured AAA operations, and surgeons without vascular or cardiothoracic fellowship training. There were 13,701 patients with elective AAA repair, with an average 30-day mortality rate of 4.5%. Significant independent predictors of lower survival were similar, except gender was not significant, but the Charlson Comorbidity Index was. When the hazard ratios associated with predictive factors were compared, surgeon factors appeared to be more important in ruptured AAA repair, and patient factors appeared more important in elective AAA repair. CONCLUSION: For elective AAA repair, and even more so for ruptured AAA repair, high-volume surgeons with subspecialty training conferred a significant survival benefit for patients. Although this would seem to argue in favor of regionalization, decisions should await a more complete understanding of the relationship between transfer time, delay in treatment, and outcome.     

Delayed aortic aneurysm enlargement due to endotension after endovascular abdominal aortic aneurysm repair

Abdominal aortic aneurysm (AAA) enlarges after successful endovascular repair, because of persistent blood flow within the aneurysm sac, or endoleak. In the absence of detectable endoleak, AAA may still expand, in part because of persistent pressurization within the excluded aneurysm, or endotension. We report three patients who underwent successful endovascular AAA repair in whom postoperative surveillance showed aneurysm regression, yet delayed AAA enlargement without demonstrable endoleak developed in all three patients. Endotension was confirmed in all three patients at elective open conversion. Our study underscores the significance of endotension as a mechanism of delayed aneurysm enlargement after successful endovascular AAA repair.     

Hormonal stress response and hemodynamic stability in patients undergoing endovascular vs. conventional abdominal aortic aneurysm repair.

BACKGROUND AND AIMS: To investigate the effect of two different surgical techniques with different anesthetic modes on intraoperative and postoperative hormonal stress response, hemodynamic stability, fluid loading and renal function in patients scheduled for elective infrarenal abdominal aortic aneurysm (AAA) repair. MATERIALS AND METHODS: Forty consecutive patients scheduled for elective infrarenal AAA repair were allocated without randomizing into two groups: an endovascular (EVAR, n = 20) and a conventional (CAR, n = 20) aneurysm repair group according to aneurysm morphology as determined by preoperative computed tomography and angiography. The EVAR group were operated under spinal anesthesia and the CAR group using general anesthesia with epidural blockade. RESULTS: Patients undergoing CAR showed lower intraoperative mean arterial pressure and significantly higher plasma norepinephrine before aortic cross-clamping and significantly higher lactate after aortic declamping and postoperatively than patients in the EVAR group. Postoperatively, vasopressin and serum cortisol were also significantly higher in the CAR group. Fluid loading and estimated blood loss were more excessive in the CAR group. CONCLUSIONS: Stress response was lower and hemodynamic stability and lower body perfusion superior and renal function also better maintained in patients undergoing EVAR under spinal anesthesia as compared to those undergoing CAR using general anesthesia with epidural blockade.