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Ruptured Versus Elective Abdominal Aortic Aneurysm Repair: Outcome and Cost
Ruptured versus Elective Abdominal Aortic Aneurysm Repair: Outcome and Cost Enrico Ascher, MD, Marcel Scheinman, MD, Patrick DePippo, MD, and William Yorkovich, RPA, Brooklyn, New York
During a recent 30-month period, we repaired 10 ruptured abdominal aortic aneurysms (RAAA) at our institution. To evaluate the survival, postoperative morbidity, and financial impact of treating RAAA, we compared these patients with 10 randomly selected patients undergoing elective AAA (EAAA). Both groups were comparable for age, gender, and incidence of diabetes, hypertension, coronary artery disease, chronic obstructive pulmonary disease (COPD), and renal failure. Although we have noted a dramatic increase in survival for RAAA (90%), the morbidity continues to be unacceptably high (60%). Efforts should be made toward better detection of AAA prior to rupture as well as development of strategies to minimize or prevent these major complications. Potential average savings accrued from one patient undergoing EAAA repair rather than RAAA repair ($93,139.21) can be used to perform screening abdominal ultrasound tests in patients at increased risk of having an AAA. (Ann Vasc Surg 1999;13:613617.)
INTRODUCTION Although there have been great improvements in operative technique and postoperative care since the repair of the first ruptured abdominal aortic aneurysm (RAAA) in 1954, death following surgery remains common.1 Furthermore, 50% of all deaths related to RAAA occur prior to arrival at the hospital.2 Patients who survive operative repair have an increased incidence of major complications such as respiratory failure, renal failure, sepsis, cardiac failure, bleeding, stroke, ischemic colitis, lower extremity ischemia, and paraplegia. In addition to the increased morbidity associated with patients who survive RAAA, there is a concomitant increase in cost to the health care system. This has not been so obvious because of the high mortality associated with RAAA. However, as survival improves and associated cost for saving RAAA patients increases, From the Division of Vascular Surgery, Department of Surgery, Maimonides Medical Center, Brooklyn, NY. Correspondence to: E. Ascher, MD, Division of Vascular Surgery, 4802 10th Avenue, Brooklyn, NY, 11219, USA.
there is further impetus for early identification of AAAs and their elective repair. To investigate this hypothesis, we retrospectively reviewed our experience with RAAA to determine how major complications associated with improved survival negatively impact cost and compared these results with elective repair. In addition, we investigated whether the price of screening abdominal ultrasound is justified if patients discovered to have an asymptomatic AAA undergo elective (EAAA) repair rather than RAAA repair.
PATIENTS AND METHODS During a 30-month period from January 1993 to June 1995, 155 patients underwent infrarenal aortic aneurysm repair at Maimonides Medical Center, Brooklyn, NY. Ten patients presented with a RAAA on admission. There were seven males and three females ranging in age from 65 to 85 years (mean 73.4 years). Thirty percent of the patients had a history of hypertension (HTN), 10% were diabetic, 20% had coronary artery disease (CAD), 20% had chronic obstructive pulmonary disease (COPD), and 613
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Table I. Preoperative risk factors
Ruptured Elective
Patients
Average age
Average admit BP
Hct (%)
HTN (%)
DM (%)
CAD (%)
CRF (%)
COPD (%)
10 10
73.4 70.8
103.3 —
41.4 40.4
30 60
10 10
20 10
20 0
20 0
DM, diabetes mellitus; Hct, hematocrit.
20% had chronic renal failure (CRF). Five patients presented with an admitting systolic blood pressure (SBP) <90 mmHg and mean admitting SBP was 103 mmHg. Nine of the 10 patients had a SBP <90 mmHg at least once prior to induction of general anesthesia. Averaged admitting hematocrit was 41.4. Preoperative radiographic testing to confirm the diagnosis of a RAAA was obtained in four patients, which included one abdominal ultrasound, one abdominal computed tomography (CT) scan, one abdominal X-ray, and one renal scan for a patient thought to be suffering from renal colic. One patient had previous knowledge of his AAA and was taken to the operating room (OR) on the basis of this knowledge and his presentation. Five patients were taken straight to the OR because of presumptive diagnosis and hemodynamic instability. Packed red blood cells (PRBCs), fresh frozen plasma (FFP), and platelets were made available once the diagnosis of RAAA was made. Once in the OR, patients were stabilized with 2.0 L of Ringer’s lactate, prepped, and draped prior to anesthetic induction. Patients who remained hypotensive despite 2.0 L of intravenous crystalloid solution underwent crash induction. Operative technique included a transperitoneal approach through a midline incision. Supraceliac control was obtained in 9 out of 10 cases followed by rapid control of the infrarenal abdominal aorta and removal of the supraceliac cross-clamp. All patients were heparinized prior to cross-clamping the aorta to avoid thrombotic complications. Tube grafts were preferentially used over bifurcated grafts despite the presence of small iliac artery aneurysms (<3 cm), but iliac artery aneurysms larger than 3 cm were repaired with a bifurcated graft. Care was taken to avoid any major venous injury. The cell saver was used in all cases. Hypothermia was avoided by increasing the temperature of the OR and ventilated gas, warming intravenous fluids, use of a forced warm air blanket (Bear Hugger), and warm peritoneal and gastric lavage when these efforts failed. Survival, morbidity, and hospital cost of patients treated for RAAA were compared with that of 10 patients randomly selected from those patients who
underwent EAAA repair. The randomization methodology was as follows: a list of 145 EAAA repairs done in chronological order was obtained from the hospital database system. The first patient and every subsequent 15th patient were selected to ensure an even time distribution. Demographics for patients undergoing EAAA repair can be found on Table I. The costs of major complications such as postoperative pulmonary failure, pneumonia, cardiac arrhythmia, mesenteric ischemia, renal failure, and myocardial infarction (MI) were recorded. Other parameters analyzed included length of stay in the surgical intensive care unit (SICU), days spent in a ward bed, nursing requirements, medical supplies, laboratory tests, medications, and transfusion of blood products. Physician fees were excluded. Results were compared using the unpaired Student’s t-test and Fisher’s exact test.
RESULTS Patients in both groups were comparable for age, gender, and incidence of diabetes, HTN, CAD, COPD, and renal function (Table I). All patients who underwent EAAA repair survived whereas only one patient who presented with a RAAA died within 30 days of surgery. The operating time for the RAAA group ranged from 120 to 540 min (mean 348 min). Aortic cross-clamp time for the RAAA group ranged from 25 to 120 min (mean 70 min). Neither of these values differed significantly from the EAAA group with means of 259 min operating time and 60 min aortic cross-clamp time. Patients undergoing RAAA repair had an averge estimated blood loss (EBL) of 3.2 L, an average intraoperative fluid requirement of 13.0 L, and an average number of units of PRBCs, FFP, and platelets transfused during surgery equaling 7.4, 2.2, and 6.8, respectively (Table II). These values were significantly greater than those for patients undergoing EAAA repair (p < 0.001). Eleven major postoperative complications occurred in 6 out of the 10 RAAA patients: (1) five patients developed pulmonary failure requiring prolonged mechanical ventilation and two of these
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Ruptured versus elective AAA repair 615
Table II. Operative blood loss and transfusion requirements
Ruptured Elective a
Patients
Average FFP (units)
Average platelets (units)
10 10
2.2 0.1
6.8a 7.2
EB loss (L)
Average intraoperative fluids (L)
Average PRBCs transfused (units)
3.2a 1.1
13.0a 6.0
7.4a 0.3
p < .001.
patients required tracheostomies; (2) two patients had cardiac arrythmias requiring intravenous antiarrhythmia medication; (3) two patients developed renal failure requiring chronic hemodialysis; (4) one patient underwent a Hartman’s procedure for mesenteric ischemia; and (5) one patient suffered a fatal MI. Five patients who developed complications survived and were discharged from the hospital. Only one patient in the EAAA repair group developed cardiac arrhythmia. Patients undergoing RAAA repair had a significantly increased length of stay in the SICU: 21.3 days on average for the RAAA group vs. 4.6 days on average for the EAAA group (p < 0.001). Average time spent on the ward was 20.4 days for the RAAA group and 6.9 days for the EAAA repair group (p < 0.001). Intraoperative blood product transfusions, intravenous crystalloid requirements, and EBL were significantly higher in the RAAA group (p < 0.001) (Table II). There was no significant difference in the average diameter of the aneurysm—8.9 cm for the RAAA group vs. 7.2 cm for the EAAA group. The greatest difference in cost between the two groups was attributed to the increased length of stay in the SICU for the RAAA group ($55,380.00 vs. $11,960.00) (Table III). Length of stay in a ward bed also significantly contributed to the difference in cost ($38,950.00 vs. $13,352.40). Unfortunately, average hospital third-party reimbursement for EAAA repair was $26,615.33 and for RAAA repair was $64,547.25. This represented a net hospital loss of $6,550.58 for EAAA repair and $61,757.87 for RAAA repair.
DISCUSSION Our experience demonstrates that increased survival from RAAA is associated with increased morbidity that leads to a tremendous cost burden on the health care system. Ninety percent of patients presenting to our institution with a RAAA survived, but at a price of four times that of an EAAA repair. Although developing strategies to minimize major
Table III. Average hospital cost per AAA
Blood products SICU days SICU medical supplies SICU labs Ward days Ward supplies Ward labs OR cost Return trips to OR/dialysis Total
Elective ($)
Ruptured ($)
400.45 11,960.00 92.40 1,352.40 13,352.40 108.10 434.70 5,465.46 0.00 33,165.91
2,118.05 55,380.00 4,132.20 6,262.20 38,950.00 321.03 1,291.50 5,697.84 12,152.30 126,305.21
complications is one obvious solution to decrease cost associated with RAAA, this seems difficult to accomplish. The average overall length of stay for a patient undergoing RAAA repair was 42 days whereas patients undergoing EAAA repair stayed 12 days. Most of the increased length of stay can be attributed to a 50% incidence of prolonged respiratory failure and a 20% incidence of renal failure requiring chronic hemodialysis postoperatively. Little data have been published addressing the hospital length of stay following RAAA repair. Bush et al.3 point to hypothermia as a major contributory factor to prolonged hospital stay (up to 34 days), while Donaldson et al.4 reported a mean hospital stay of 20 days for RAAA, but with an overall survival of 57%. Differences in the distribution of risk factors (COPD, CRF, CAD) between the two groups could not be determined because of the small number of patients in the study. However, the outcome for the EAAA repair group is comparable to that for the remaining 135 EAAA patients operated on during the same period (data not shown). Therefore, it is our impression that even if these risk factors were compared between both groups, the overall outcome would not have been significantly different. Factors that likely influenced our improved sur-
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vival were limited intraoperative blood loss with aggressive blood product and fluid replacement. EBL >4.0 L has been found to be associated with increased mortality.5 Furthermore, increased transfusion requirements have also been associated with high postoperative mortality.6-8 Patients with blood transfusion requirements of >19 units have been associated with mortality rates ranging from 83 to 100%.7,8 The average EBL for the RAAA group was 3.2 L whereas patients undergoing EAAA had an EBL of 1.1 L. Patients in our RAAA group required on average 7.4 units of PRBCs in the OR whereas patients undergoing elective repair averaged 0.3 units of PRBCs. In addition, the cell saver was used in all cases. Other risk factors that have been found to influence early complications and death are duration of cross-clamp time, preoperative shock, use of a suprarenal cross-clamp, and a history of CAD.9 Postoperative complications associated with early death are myocardial failure, sepsis, renal failure, and colon ischemia.10 There was no significant difference in aortic cross-clamp time between the RAAA group and patients undergoing EAAA repair. We used a suprarenal clamp in 9 out of 10 patients with a RAAA. Decreased intraoperative blood loss, transfusion requirement, and intraoperative hypotension could be attributed to the use of the suprarenal clamp. Preoperative hypotension is the most frequently cited prognostic factor, associated with decreased survival and early death.7,8,11,12 In our series five patients from the RAAA group presented with an admitting SBP <90 mmHg and the mean admitting SBP for this group equaled 103 mmHg. Nine out of 10 patients had a SBP of <90 mmHg at least once prior to induction of general anesthesia. Some practitioners have theorized that use of a suprarenal clamp causes increased myocardial strain due to a rapid rise in SBP and subsequent increased cardiac morbidity and mortality. Other disadvantages to supraceliac clamping include mesenteric and renal ischemia. We had one case of mesenteric ischemia requiring a Hartman’s procedure, one fatal MI, and two cases of CRF requiring hemodialysis. It is not clear whether these complications were due to the use of a supraceliac clamp or preoperative hypotension combined with pre-existing atherosclerotic occlusive disease. We find that the benefits of hemodynamic stability offered by expeditious supraceliac cross-clamping outweigh the risk of ischemic complications that may be associated with its use. Operative duration for RAAA has also been found to correlate with mortality. Operations lasting longer than 300 min had a significantly higher
Annals of Vascular Surgery
mortality compared to operations that lasted 120 to 180 min.5 Others have reported 100% mortality for operations over 400 min.13 The average time spent in the OR for the RAAA group was 384 min while actual operating time was 348 min. This was not statistically different from the operating time for patients undergoing EAAA repair. Factors that reduced operative time and, more importantly, aortic cross-clamp time were preferential use of tube grafts despite the presence of limited iliac aneurysms (<3 cm) and experienced vascular surgeons. In addition, there were no major intraoperative complications such as cardiac arrest,14,15 venous injury,12 and intestinal or splenic injury.4 Hypothermia is a problem frequently encountered in patients undergoing RAAA repair and has been found to be associated with coagulopathy, acidosis, and decreased oxygen delivery.3 We avoided intraoperative hypothermia in our patients, and this may have contributed to a better outcome. Beside all the aforementioned measures that may have contributed to a better outcome, the high rate of 90% survival in this series may also be due in part to the small number of patients in the series rather than other innovative care practice. Although survival was improved dramatically in this cohort of RAAA patients, there was a high frequency of major complications with associated increased cost compared to individuals undergoing EAAA repair. The most effective means to reduce morbidity and cost from RAAA may be screening patients at high risk for AAA and offering elective repair to these individuals prior to rupture. The incidence of AAA for men age 60 and greater is estimated to be between 2.0% and 7.8%.16 Individuals with additional risk factors such as smoking, HTN, or atherosclerotic vascular disease have a higher prevalence.17 Overal, approximately 6% of aneurysms >4 cm in diameter will rupture annually,18 and RAAA is reported to cause 1.2% of male deaths and 0.6% of female deaths of individuals older than 65 years in the United States.19 Sensitivity of the physical exam in detecting AAA has ranged from 22 to 96%. Thus, a physical exam cannot be relied on to effectively screen patients suspected of having an AAA. Ultrasonography is a reliable test for detecting AAA, with sensitivity rates of between 82 and 99%.20 Wolf et al.21 recently reported a 3.2% incidence of an AAA 4.0 cm or greater in 475 patients screened for AAA during lower extremity arterial evaluation in the vascular laboratory. Screening for AAA in male smokers over age 65 in this same patient population yielded a prevalence of 8.8%. The cost of identifying an aneurysm of 4.0 cm or greater
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ranged from $561 to $1603, depending on the selection of the population to be screened. These figures compare favorably with the cost of identifying a single breast cancer, which is estimated at $23,000 with the use of physical exam and screening mammography.22 The familial tendency of AAA has been noted by Clifton,23 Tilson et al.,24 and most recently by Webster et al.25 In Webster’s study, AAA was found in 8.2% of first-degree relatives over age 55. Clearly there are select patient populations that have an increased incidence of AAA. This would include males over age 65 with a history of symptomatic lower extremity vascular disease, carotid occlusive disease, tobacco use, or family history of an AAA. Screening this population wtih abdominal ultrasound would be justified to preferentially repair AAA prior to rupture. REFERENCES 1. Johansen K, Kohler TR, Nicholls C, Zierler RE, Clowes AW, Kazmers A. Ruptured abdominal aortic aneurysm: the Harborview experience. J Vasc Surg 1991;13:240-247. 2. Johannson G, Swedenborg J. Ruptured abdominal aortic aneurysm: a study of incidence and mortality. Br J Surg 1986; 73:101-103. 3. Bush HL Jr, Hydo LJ, Fischer E, Fantini GA, Silane MF, Barie PS. Hypothermia during elective abdominal aortic aneurysm repair: the high price of avoidable morbidity. J Vasc Surg 1995;21:392-402. 4. Donaldson MC, Rosenberg JM, Bucknam CA. Factors affecting survival after ruptured abdominal aortic aneurysm. J Vasc Surg 1985;2:564-570. 5. Hidebrand HD, Fry PD. Ruptured abdominal aortic aneurysm. Surgery 1975;77:540-544. 6. Morris PJ, Buxton BF, Flac C. Ruptured abdominal aortic aneurysms presenting to a general hospital. Med J Aust 1975;1:555-558. 7. Sink JD, Myers RT, James PM. Ruptured abdominal aortic aneurysms: review of 33 cases treated surgically and discussion of prognostic indicators. Am Surg 1976;42:303-307. 8. VanHeeckeren DW. Ruptured abdominal aortic aneurysm. Am J Surg 1970;119:402-407. 9. Bauer EP, Redaelli C, von Segesser LK, Turina MI. Ruptured abdominal aortic aneurysms: predictors for early complications and death. Surgery 1993;114:31-35.
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10. Ouriel K, Geary K, Green RM, Fiore W, Geary JE, DeWeese JA. Factors determining survival after ruptured aortic aneurysm: the hospital, the surgeon and the patient. J Vasc Surg 1990;11:493-496. 11. Chiariello L, Reul Jr GJ, Wukasch DC, et al. Ruptured abdominal aortic aneurysm: treatment and review of eightyseven patients. Am J Surg 1974;128:735-738. 12. DiGiovanni R, Volpetti R, Berkowitz H, et al. Twenty-one years’ experience with ruptured abdominal aortic aneurysms. Surg Gynecol Obstet 1975;141:859-862. 13. Wakefield TW, Whitehouse WM, Wu SC, et al. Abdominal aortic aneurysm rupture: statistical analysis of factors affecting outcome of surgical treatment. Surgery 1982;91:586596. 14. Gardner RJ, Gardner NL, Tarnam TJ, et al. The surgical experience and a one to sixteen year follow-up of 277 abdominal aortic aneurysms. Am J Surg 1978;135:226-230. 15. Lawrie GM, Morris Jr GC, Crawford ES, et al. Improved results of operation for ruptured abdominal aortic aneurysms. Surgery 1979;85:483-488. 16. O’Kelly TJ, Heather BP. General practice-based population screening for abdominal aortic aneurysms: a pilot study. Br J Surg 1989;76:479-480. 17. Ballard DF, Etchason JA, Hilborne LH, et al. Abdominal aortic aneurysm surgery: a literature review and ratings of appropriateness and necessity. Santa Monica, CA: RAND, 1992, JRA-04. 18. Cronenwett JL, Murphy TF, Zelenock GB, et al. Actuarial analysis of variables associated with rupture of small abdominal aortic aneurysms. Surgery 1985;98:472-483. 19. Vital Statistics of the United States, 1974, Mortality, Vol. 2, part A. Washington, DC: U.S. Department of Health Education and Welfare, 1974, Publication no. PHS 79-1101. 20. Quill DS, Colgan MP, Sumner DS. Ultrasonic screening for the detection of abdominal aortic aneurysms. Surg Clin of North Am 1989;69:713-720. 21. Wolf GW, Otis SM, Schwend RB, Bernstein EF. Screening for abdominal aortic aneurysms during lower extremity arterial evaluation in the vascular laboratory. J Vasc Surg 1995;22:417-423. 22. Russell JGB. Is screening for abdominal aortic aneurysm worthwhile? Clin Radiol 1990;41:181-184. 23. Clifton MA. Familial abdominal aortic aneurysms. Br J Surg 1977;64:765-766. 24. Tilson MD, Seashore MR. Fifty families with abdominal aortic aneurysms in two or more first order relatives. Am J Surg 1984;147:551-553. 25. Webster MW, Ferrell RE, St. Jean PL, Majumder PP, Fogel SR, Steed DL. Ultrasound screening of first degree relatives of patients with an abdominal aortic aneurysm. J Vasc Surg 1991;13:9-14.
During a recent 30-month period, we repaired 10 ruptured abdominal aortic aneurysms (RAAA) at our institution. To evaluate the survival, postoperative morbidity, and financial impact of treating RAAA, we compared these patients with 10 randomly selected patients undergoing elective AAA (EAAA). Both groups were comparable for age, gender, and incidence of diabetes, hypertension, coronary artery disease, chronic obstructive pulmonary disease (COPD), and renal failure. Although we have noted a dramatic increase in survival for RAAA (90%), the morbidity continues to be unacceptably high (60%). Efforts should be made toward better detection of AAA prior to rupture as well as development of strategies to minimize or prevent these major complications. Potential average savings accrued from one patient undergoing EAAA repair rather than RAAA repair ($93,139.21) can be used to perform screening abdominal ultrasound tests in patients at increased risk of having an AAA. (Ann Vasc Surg 1999;13:613617.)
INTRODUCTION Although there have been great improvements in operative technique and postoperative care since the repair of the first ruptured abdominal aortic aneurysm (RAAA) in 1954, death following surgery remains common.1 Furthermore, 50% of all deaths related to RAAA occur prior to arrival at the hospital.2 Patients who survive operative repair have an increased incidence of major complications such as respiratory failure, renal failure, sepsis, cardiac failure, bleeding, stroke, ischemic colitis, lower extremity ischemia, and paraplegia. In addition to the increased morbidity associated with patients who survive RAAA, there is a concomitant increase in cost to the health care system. This has not been so obvious because of the high mortality associated with RAAA. However, as survival improves and associated cost for saving RAAA patients increases, From the Division of Vascular Surgery, Department of Surgery, Maimonides Medical Center, Brooklyn, NY. Correspondence to: E. Ascher, MD, Division of Vascular Surgery, 4802 10th Avenue, Brooklyn, NY, 11219, USA.
there is further impetus for early identification of AAAs and their elective repair. To investigate this hypothesis, we retrospectively reviewed our experience with RAAA to determine how major complications associated with improved survival negatively impact cost and compared these results with elective repair. In addition, we investigated whether the price of screening abdominal ultrasound is justified if patients discovered to have an asymptomatic AAA undergo elective (EAAA) repair rather than RAAA repair.
PATIENTS AND METHODS During a 30-month period from January 1993 to June 1995, 155 patients underwent infrarenal aortic aneurysm repair at Maimonides Medical Center, Brooklyn, NY. Ten patients presented with a RAAA on admission. There were seven males and three females ranging in age from 65 to 85 years (mean 73.4 years). Thirty percent of the patients had a history of hypertension (HTN), 10% were diabetic, 20% had coronary artery disease (CAD), 20% had chronic obstructive pulmonary disease (COPD), and 613
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Table I. Preoperative risk factors
Ruptured Elective
Patients
Average age
Average admit BP
Hct (%)
HTN (%)
DM (%)
CAD (%)
CRF (%)
COPD (%)
10 10
73.4 70.8
103.3 —
41.4 40.4
30 60
10 10
20 10
20 0
20 0
DM, diabetes mellitus; Hct, hematocrit.
20% had chronic renal failure (CRF). Five patients presented with an admitting systolic blood pressure (SBP) <90 mmHg and mean admitting SBP was 103 mmHg. Nine of the 10 patients had a SBP <90 mmHg at least once prior to induction of general anesthesia. Averaged admitting hematocrit was 41.4. Preoperative radiographic testing to confirm the diagnosis of a RAAA was obtained in four patients, which included one abdominal ultrasound, one abdominal computed tomography (CT) scan, one abdominal X-ray, and one renal scan for a patient thought to be suffering from renal colic. One patient had previous knowledge of his AAA and was taken to the operating room (OR) on the basis of this knowledge and his presentation. Five patients were taken straight to the OR because of presumptive diagnosis and hemodynamic instability. Packed red blood cells (PRBCs), fresh frozen plasma (FFP), and platelets were made available once the diagnosis of RAAA was made. Once in the OR, patients were stabilized with 2.0 L of Ringer’s lactate, prepped, and draped prior to anesthetic induction. Patients who remained hypotensive despite 2.0 L of intravenous crystalloid solution underwent crash induction. Operative technique included a transperitoneal approach through a midline incision. Supraceliac control was obtained in 9 out of 10 cases followed by rapid control of the infrarenal abdominal aorta and removal of the supraceliac cross-clamp. All patients were heparinized prior to cross-clamping the aorta to avoid thrombotic complications. Tube grafts were preferentially used over bifurcated grafts despite the presence of small iliac artery aneurysms (<3 cm), but iliac artery aneurysms larger than 3 cm were repaired with a bifurcated graft. Care was taken to avoid any major venous injury. The cell saver was used in all cases. Hypothermia was avoided by increasing the temperature of the OR and ventilated gas, warming intravenous fluids, use of a forced warm air blanket (Bear Hugger), and warm peritoneal and gastric lavage when these efforts failed. Survival, morbidity, and hospital cost of patients treated for RAAA were compared with that of 10 patients randomly selected from those patients who
underwent EAAA repair. The randomization methodology was as follows: a list of 145 EAAA repairs done in chronological order was obtained from the hospital database system. The first patient and every subsequent 15th patient were selected to ensure an even time distribution. Demographics for patients undergoing EAAA repair can be found on Table I. The costs of major complications such as postoperative pulmonary failure, pneumonia, cardiac arrhythmia, mesenteric ischemia, renal failure, and myocardial infarction (MI) were recorded. Other parameters analyzed included length of stay in the surgical intensive care unit (SICU), days spent in a ward bed, nursing requirements, medical supplies, laboratory tests, medications, and transfusion of blood products. Physician fees were excluded. Results were compared using the unpaired Student’s t-test and Fisher’s exact test.
RESULTS Patients in both groups were comparable for age, gender, and incidence of diabetes, HTN, CAD, COPD, and renal function (Table I). All patients who underwent EAAA repair survived whereas only one patient who presented with a RAAA died within 30 days of surgery. The operating time for the RAAA group ranged from 120 to 540 min (mean 348 min). Aortic cross-clamp time for the RAAA group ranged from 25 to 120 min (mean 70 min). Neither of these values differed significantly from the EAAA group with means of 259 min operating time and 60 min aortic cross-clamp time. Patients undergoing RAAA repair had an averge estimated blood loss (EBL) of 3.2 L, an average intraoperative fluid requirement of 13.0 L, and an average number of units of PRBCs, FFP, and platelets transfused during surgery equaling 7.4, 2.2, and 6.8, respectively (Table II). These values were significantly greater than those for patients undergoing EAAA repair (p < 0.001). Eleven major postoperative complications occurred in 6 out of the 10 RAAA patients: (1) five patients developed pulmonary failure requiring prolonged mechanical ventilation and two of these
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Ruptured versus elective AAA repair 615
Table II. Operative blood loss and transfusion requirements
Ruptured Elective a
Patients
Average FFP (units)
Average platelets (units)
10 10
2.2 0.1
6.8a 7.2
EB loss (L)
Average intraoperative fluids (L)
Average PRBCs transfused (units)
3.2a 1.1
13.0a 6.0
7.4a 0.3
p < .001.
patients required tracheostomies; (2) two patients had cardiac arrythmias requiring intravenous antiarrhythmia medication; (3) two patients developed renal failure requiring chronic hemodialysis; (4) one patient underwent a Hartman’s procedure for mesenteric ischemia; and (5) one patient suffered a fatal MI. Five patients who developed complications survived and were discharged from the hospital. Only one patient in the EAAA repair group developed cardiac arrhythmia. Patients undergoing RAAA repair had a significantly increased length of stay in the SICU: 21.3 days on average for the RAAA group vs. 4.6 days on average for the EAAA group (p < 0.001). Average time spent on the ward was 20.4 days for the RAAA group and 6.9 days for the EAAA repair group (p < 0.001). Intraoperative blood product transfusions, intravenous crystalloid requirements, and EBL were significantly higher in the RAAA group (p < 0.001) (Table II). There was no significant difference in the average diameter of the aneurysm—8.9 cm for the RAAA group vs. 7.2 cm for the EAAA group. The greatest difference in cost between the two groups was attributed to the increased length of stay in the SICU for the RAAA group ($55,380.00 vs. $11,960.00) (Table III). Length of stay in a ward bed also significantly contributed to the difference in cost ($38,950.00 vs. $13,352.40). Unfortunately, average hospital third-party reimbursement for EAAA repair was $26,615.33 and for RAAA repair was $64,547.25. This represented a net hospital loss of $6,550.58 for EAAA repair and $61,757.87 for RAAA repair.
DISCUSSION Our experience demonstrates that increased survival from RAAA is associated with increased morbidity that leads to a tremendous cost burden on the health care system. Ninety percent of patients presenting to our institution with a RAAA survived, but at a price of four times that of an EAAA repair. Although developing strategies to minimize major
Table III. Average hospital cost per AAA
Blood products SICU days SICU medical supplies SICU labs Ward days Ward supplies Ward labs OR cost Return trips to OR/dialysis Total
Elective ($)
Ruptured ($)
400.45 11,960.00 92.40 1,352.40 13,352.40 108.10 434.70 5,465.46 0.00 33,165.91
2,118.05 55,380.00 4,132.20 6,262.20 38,950.00 321.03 1,291.50 5,697.84 12,152.30 126,305.21
complications is one obvious solution to decrease cost associated with RAAA, this seems difficult to accomplish. The average overall length of stay for a patient undergoing RAAA repair was 42 days whereas patients undergoing EAAA repair stayed 12 days. Most of the increased length of stay can be attributed to a 50% incidence of prolonged respiratory failure and a 20% incidence of renal failure requiring chronic hemodialysis postoperatively. Little data have been published addressing the hospital length of stay following RAAA repair. Bush et al.3 point to hypothermia as a major contributory factor to prolonged hospital stay (up to 34 days), while Donaldson et al.4 reported a mean hospital stay of 20 days for RAAA, but with an overall survival of 57%. Differences in the distribution of risk factors (COPD, CRF, CAD) between the two groups could not be determined because of the small number of patients in the study. However, the outcome for the EAAA repair group is comparable to that for the remaining 135 EAAA patients operated on during the same period (data not shown). Therefore, it is our impression that even if these risk factors were compared between both groups, the overall outcome would not have been significantly different. Factors that likely influenced our improved sur-
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vival were limited intraoperative blood loss with aggressive blood product and fluid replacement. EBL >4.0 L has been found to be associated with increased mortality.5 Furthermore, increased transfusion requirements have also been associated with high postoperative mortality.6-8 Patients with blood transfusion requirements of >19 units have been associated with mortality rates ranging from 83 to 100%.7,8 The average EBL for the RAAA group was 3.2 L whereas patients undergoing EAAA had an EBL of 1.1 L. Patients in our RAAA group required on average 7.4 units of PRBCs in the OR whereas patients undergoing elective repair averaged 0.3 units of PRBCs. In addition, the cell saver was used in all cases. Other risk factors that have been found to influence early complications and death are duration of cross-clamp time, preoperative shock, use of a suprarenal cross-clamp, and a history of CAD.9 Postoperative complications associated with early death are myocardial failure, sepsis, renal failure, and colon ischemia.10 There was no significant difference in aortic cross-clamp time between the RAAA group and patients undergoing EAAA repair. We used a suprarenal clamp in 9 out of 10 patients with a RAAA. Decreased intraoperative blood loss, transfusion requirement, and intraoperative hypotension could be attributed to the use of the suprarenal clamp. Preoperative hypotension is the most frequently cited prognostic factor, associated with decreased survival and early death.7,8,11,12 In our series five patients from the RAAA group presented with an admitting SBP <90 mmHg and the mean admitting SBP for this group equaled 103 mmHg. Nine out of 10 patients had a SBP of <90 mmHg at least once prior to induction of general anesthesia. Some practitioners have theorized that use of a suprarenal clamp causes increased myocardial strain due to a rapid rise in SBP and subsequent increased cardiac morbidity and mortality. Other disadvantages to supraceliac clamping include mesenteric and renal ischemia. We had one case of mesenteric ischemia requiring a Hartman’s procedure, one fatal MI, and two cases of CRF requiring hemodialysis. It is not clear whether these complications were due to the use of a supraceliac clamp or preoperative hypotension combined with pre-existing atherosclerotic occlusive disease. We find that the benefits of hemodynamic stability offered by expeditious supraceliac cross-clamping outweigh the risk of ischemic complications that may be associated with its use. Operative duration for RAAA has also been found to correlate with mortality. Operations lasting longer than 300 min had a significantly higher
Annals of Vascular Surgery
mortality compared to operations that lasted 120 to 180 min.5 Others have reported 100% mortality for operations over 400 min.13 The average time spent in the OR for the RAAA group was 384 min while actual operating time was 348 min. This was not statistically different from the operating time for patients undergoing EAAA repair. Factors that reduced operative time and, more importantly, aortic cross-clamp time were preferential use of tube grafts despite the presence of limited iliac aneurysms (<3 cm) and experienced vascular surgeons. In addition, there were no major intraoperative complications such as cardiac arrest,14,15 venous injury,12 and intestinal or splenic injury.4 Hypothermia is a problem frequently encountered in patients undergoing RAAA repair and has been found to be associated with coagulopathy, acidosis, and decreased oxygen delivery.3 We avoided intraoperative hypothermia in our patients, and this may have contributed to a better outcome. Beside all the aforementioned measures that may have contributed to a better outcome, the high rate of 90% survival in this series may also be due in part to the small number of patients in the series rather than other innovative care practice. Although survival was improved dramatically in this cohort of RAAA patients, there was a high frequency of major complications with associated increased cost compared to individuals undergoing EAAA repair. The most effective means to reduce morbidity and cost from RAAA may be screening patients at high risk for AAA and offering elective repair to these individuals prior to rupture. The incidence of AAA for men age 60 and greater is estimated to be between 2.0% and 7.8%.16 Individuals with additional risk factors such as smoking, HTN, or atherosclerotic vascular disease have a higher prevalence.17 Overal, approximately 6% of aneurysms >4 cm in diameter will rupture annually,18 and RAAA is reported to cause 1.2% of male deaths and 0.6% of female deaths of individuals older than 65 years in the United States.19 Sensitivity of the physical exam in detecting AAA has ranged from 22 to 96%. Thus, a physical exam cannot be relied on to effectively screen patients suspected of having an AAA. Ultrasonography is a reliable test for detecting AAA, with sensitivity rates of between 82 and 99%.20 Wolf et al.21 recently reported a 3.2% incidence of an AAA 4.0 cm or greater in 475 patients screened for AAA during lower extremity arterial evaluation in the vascular laboratory. Screening for AAA in male smokers over age 65 in this same patient population yielded a prevalence of 8.8%. The cost of identifying an aneurysm of 4.0 cm or greater
Vol. 13, No. 6, 1999
ranged from $561 to $1603, depending on the selection of the population to be screened. These figures compare favorably with the cost of identifying a single breast cancer, which is estimated at $23,000 with the use of physical exam and screening mammography.22 The familial tendency of AAA has been noted by Clifton,23 Tilson et al.,24 and most recently by Webster et al.25 In Webster’s study, AAA was found in 8.2% of first-degree relatives over age 55. Clearly there are select patient populations that have an increased incidence of AAA. This would include males over age 65 with a history of symptomatic lower extremity vascular disease, carotid occlusive disease, tobacco use, or family history of an AAA. Screening this population wtih abdominal ultrasound would be justified to preferentially repair AAA prior to rupture. REFERENCES 1. Johansen K, Kohler TR, Nicholls C, Zierler RE, Clowes AW, Kazmers A. Ruptured abdominal aortic aneurysm: the Harborview experience. J Vasc Surg 1991;13:240-247. 2. Johannson G, Swedenborg J. Ruptured abdominal aortic aneurysm: a study of incidence and mortality. Br J Surg 1986; 73:101-103. 3. Bush HL Jr, Hydo LJ, Fischer E, Fantini GA, Silane MF, Barie PS. Hypothermia during elective abdominal aortic aneurysm repair: the high price of avoidable morbidity. J Vasc Surg 1995;21:392-402. 4. Donaldson MC, Rosenberg JM, Bucknam CA. Factors affecting survival after ruptured abdominal aortic aneurysm. J Vasc Surg 1985;2:564-570. 5. Hidebrand HD, Fry PD. Ruptured abdominal aortic aneurysm. Surgery 1975;77:540-544. 6. Morris PJ, Buxton BF, Flac C. Ruptured abdominal aortic aneurysms presenting to a general hospital. Med J Aust 1975;1:555-558. 7. Sink JD, Myers RT, James PM. Ruptured abdominal aortic aneurysms: review of 33 cases treated surgically and discussion of prognostic indicators. Am Surg 1976;42:303-307. 8. VanHeeckeren DW. Ruptured abdominal aortic aneurysm. Am J Surg 1970;119:402-407. 9. Bauer EP, Redaelli C, von Segesser LK, Turina MI. Ruptured abdominal aortic aneurysms: predictors for early complications and death. Surgery 1993;114:31-35.
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10. Ouriel K, Geary K, Green RM, Fiore W, Geary JE, DeWeese JA. Factors determining survival after ruptured aortic aneurysm: the hospital, the surgeon and the patient. J Vasc Surg 1990;11:493-496. 11. Chiariello L, Reul Jr GJ, Wukasch DC, et al. Ruptured abdominal aortic aneurysm: treatment and review of eightyseven patients. Am J Surg 1974;128:735-738. 12. DiGiovanni R, Volpetti R, Berkowitz H, et al. Twenty-one years’ experience with ruptured abdominal aortic aneurysms. Surg Gynecol Obstet 1975;141:859-862. 13. Wakefield TW, Whitehouse WM, Wu SC, et al. Abdominal aortic aneurysm rupture: statistical analysis of factors affecting outcome of surgical treatment. Surgery 1982;91:586596. 14. Gardner RJ, Gardner NL, Tarnam TJ, et al. The surgical experience and a one to sixteen year follow-up of 277 abdominal aortic aneurysms. Am J Surg 1978;135:226-230. 15. Lawrie GM, Morris Jr GC, Crawford ES, et al. Improved results of operation for ruptured abdominal aortic aneurysms. Surgery 1979;85:483-488. 16. O’Kelly TJ, Heather BP. General practice-based population screening for abdominal aortic aneurysms: a pilot study. Br J Surg 1989;76:479-480. 17. Ballard DF, Etchason JA, Hilborne LH, et al. Abdominal aortic aneurysm surgery: a literature review and ratings of appropriateness and necessity. Santa Monica, CA: RAND, 1992, JRA-04. 18. Cronenwett JL, Murphy TF, Zelenock GB, et al. Actuarial analysis of variables associated with rupture of small abdominal aortic aneurysms. Surgery 1985;98:472-483. 19. Vital Statistics of the United States, 1974, Mortality, Vol. 2, part A. Washington, DC: U.S. Department of Health Education and Welfare, 1974, Publication no. PHS 79-1101. 20. Quill DS, Colgan MP, Sumner DS. Ultrasonic screening for the detection of abdominal aortic aneurysms. Surg Clin of North Am 1989;69:713-720. 21. Wolf GW, Otis SM, Schwend RB, Bernstein EF. Screening for abdominal aortic aneurysms during lower extremity arterial evaluation in the vascular laboratory. J Vasc Surg 1995;22:417-423. 22. Russell JGB. Is screening for abdominal aortic aneurysm worthwhile? Clin Radiol 1990;41:181-184. 23. Clifton MA. Familial abdominal aortic aneurysms. Br J Surg 1977;64:765-766. 24. Tilson MD, Seashore MR. Fifty families with abdominal aortic aneurysms in two or more first order relatives. Am J Surg 1984;147:551-553. 25. Webster MW, Ferrell RE, St. Jean PL, Majumder PP, Fogel SR, Steed DL. Ultrasound screening of first degree relatives of patients with an abdominal aortic aneurysm. J Vasc Surg 1991;13:9-14.