Emergency operation in patients with symptomatic abdominal aortic aneurysms

Emergency Operation in Patients With Symptomatic Abdominal Aortic Aneurysms Randall W. Buss, MD, G. Patrick Clagett, MD, Daniel F. Fisher, Jr., ~ID, Richard E. Fry, MD, John F. Eidt, MD, Ted H. Humble, MD, William J. Fry, r~ID,Dallas.Texas

To assess the need for routine preoperative computerized tomography scanning to discern patients with rupture among those presenting with acutely symptomatic abdominal aortic aneurysms, a retrospeclive review was performed. During a 5-year period, all patients presenting with symptomatic aneurysm underwent emergency operation without preoperative computerized tomography. The mortality rate was not significantly different among patients with symptomatic, intact aneurysms undergoing emergency operation (3 percent) and those without symptoms having elective operation (5 percent). The mortality rate of patients with ruptured aneurysms was 68 percent. We concluded that the addition of preoperative computerized tomography to the clinical evaluation would not have improved ihesr results. Furthermore, since it is expensive and delays emergency operation in patients with ruptured aneurysms, computerized tomography seems rarely indicated in symptomatic patients with obvious aneurysms,

From the Universityof TexasSouthwesternMedical Centerat Dallas, Department of Surgery;the Dallas VeteransAdministration Medical Center; and Parkland MemorialHospital,Dallas,Texas. Requests for reprints should be addressed to G. Patrick Clagett, MD, The Universityof TexasSouthwesternMedical Center, Department of Surgery,5323 Harry Hines Boulevard,Dallas, Texas 752359031. Presentedat the 40th Annual Meetingof the SouthwesternSurgical Congress,Phoenix,Arizona,April 10-13, !988.

outine computerized tomographyhas been advocated R in symptomatic patients to differentiate ruptured from intact, nonruptured abdominal aortic aneurysms so that patients with intact aneurysms can be spared emergency operation [1,2]. Such an approach is based on reports that patients with intact aneurysms undergoing emergency operation have higher morbidity and mortality rates than those having elective operations [3-7]. To assess the validity of this approach, an analysis was performed of contemporary results of an aggressive approach, whereby all acutely symptomatic patients with obvious aneurysm underwent immediate repair without preoperative computerized tomography. PATIENTS AND M E T H O D S Charts of all patients who underwent surgery for abdominal aortic aneurysm were reviewed for the past 5 years. Patients with concomitant renovascular or visceral artery repair were excluded. Patients were divided into three groups: asymptomatic patients undergoing elective operation (Group I), symptomatic patients undergoing emergency operations who were found to have intact aneurysms (Group II), and patients undergoing emergency operations for ruptured aneurysms (Group I!I). Risk factors, preoperative and intraoperative factors, and postoperative outcomes among the groups were compared. RESULTS During a 5-year period, 212 patients had repair of abdominal aortic aneurysms. Of these, 155 patients were asymptomatic and had elective operations. The remaining 57 patients presented to the emergency room complaining of recent onset of abdominal pain, back pain, or both. These patients underwent emergency operation; 23 (40 percent) were found to have ruptured aneurysms and 34 (60 percent), intact aneurysms. Patients with obvious aneurysms who were hemodynamically unstable were taken directly to the operating room. However, in most patients, the diagnosis was not obvious to the initial examining physicians, and surgical consultation was obtained after some delay. During this delay, several tests were performed. All patients had abdominal plain films and 21 received ultrasonography. Once the presence of symptomatic aortic aneurysm was established, patients were taken immediately to the operating room. The mean time from emergency room admission to skin incision was 5.2 4- 1 hours for patients with ruptured aneurysms and 6.2 4-1 hours for patients with intact aneurysms. This difference was not significant. The patient characteristics, associated risk factors, and comorbid conditions for asymptomatic patients undergoing elective aneurysm repair and symptomatic pa-

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tients undergoing emergency operation who had intact or ruptured aneurysms are listed in Table I. In general, patients with ruptured aneurysms were older and tended to have more coexisting medical illnesses, but there were no significant differences between the three groups except for larger aneurysms among patients with rupture. The use of clinical criteria to determine preoperatively who among the symptomatic patients had rupture was generally unreliable. Preoperative assessment of hemodynamic stability and the hematocrit value is shown in Table II. Using the combined clinical criteria of systolic blood pressure of less than 100 mm Hg and hematocrit value of less than 37 percent, 16 of 23 patients with rupture (70 percent) would have been identified preoperatively [5]. Postural hemodynamic changes (tilt test) were assessed in 35 symptomatic patients. In 12 of 14 patients with rupture (86 percent), the test result was positive in comparison to 1 of 21 patients with intact aneurysms (5 percent; p <0.001). Operative factors among patients with elective repair and those having emergency operation for intact or ruptured aneurysms are shown in Table II. In comparing elective patients with those having emergency operation for intact aneurysms, there were no significant differences in operative blood loss, blood replacement, and crystalloid and plasma administered. Not surprisingly, patients with rupture had significantly greater blood loss, blood replacement, and operative time. Six patients with intact aneurysms undergoing emergency operation were judged to have other conditions that TABLE

TABLE l Patient Characteristics by Type of Operation*

Mean age (yr) Men Smoking Coronary disease Hypertension COPD CVA

Diabetes mellitus Aneurysm size (cm)

Elective

Emergency Intact A Ruptured A

(n = 55)

(n = 34)

(n = 23)

66 91 90 58 61 53 16 9 5.6 4- 0.4

66 91 84 54 67 63 26 18 6.4 4- 0.6

70 83 94 60 40 60 20 13 8.9 4- 0.9 t

A = aneurysm; COPD = chronic obstructive pulmonary disease; CVA = cardiovascular accident. 9 All values expressed as percentages unless otherwise indicated. t p <0.02.

accounted for preoperative symptoms. These included myocardial infarction, sigmoid diverticulitis, cholelithiasis with common bile duct stones, renal calculus, internal hernia, and intraabdominal lymphoma. All of these patients had successful aneurysm repair and concomitant or staged correction of other intraabdominal pathologic abnormalities when indicated. Although there were misdiagnoses of the causes of symptoms, there were no misdiagnoses of the presence of aneurysm. The postoperative course and total morbidity and mortality rates are shown in Table II. In comparing pa-

II

Preoperative, Intraoperatlve, and Postoperative Courses"

I: Elective

I1: Intact A

(n = 155)

(n = 34)

Emergency Ill: Ruptured A (n = 23)

AnaTysis by Group (p value) I vs Ill II vs Ill

I vs II

Preoperative Factors Systolic pressure (ram Hg) Pulse rate (beats/rain) Positive tilt testt Hematocrit value (%)

137 4- 4

144 4- 4

76 4. 1 ... 41 4- 0.3

82 4- 3 1/21 (5) 42 4- 1

109 4. 11

NS

93 4- 5 12/14 (86) 36 4- 2

NS . . NS

.

.

.

<0.001

<0.065

<0.001 <0.001

NS <0.001 <0.025

.

Intraoperative Factors I-lypotension (n) t Blood loss (liters) Fluid replacement (liters) Crystallold Blood Plasma Operative time (rain) Crossclamp time (rain)

8(5) 2.1 4- 0.2 6.3 2.2 0.4 270

4444-

0.3 0.2 0.1 7 77 4- 4

3(9) 1.7 4- 0.2 5.5 1.8 0.3 245 71

444. 44-

0.4 0.2 0.1 15 7

17(74) 5.5 4- 1.4

NS NS

<0.01 <0.001

<0.01 <0.001

7.6 5.7 1.0 274 98

NS NS NS NS NS

NS <0.001 <0.001 NS NS

NS <0.005 <0.05 <0.05 NS

NS NS NS NS NS

<0.001 <0.001 <0.005 <0.01 <0.001

<0.05 <0.05 <0.05 <0.01 <0.001

44444-

1.5 1.5 0.3 23 10

Postoperative Course Hospital time (d) Ventilator ICU Discharge Total morbidity (%) Mortality (%)I

1.6 4- 0.2

3.8 4- 0.3 14.1 4- 2.2 37.5 4.5

2.8 4- 0.9 6.0 4- 1.2 18.3 4- 3.2 38.5 2.9

14.2 4- 11.4 18.0 4- 11.8 48.0 4- 28.7 95 68.1

A = aneurysm. 9 Values In parentheses are percentages. t Positive result: 10 percent decrease in systolic blood pressure, 10 percent increase in pulse rate upon sitting upright from supine position, or both. t Blood pressure less than 90 mm Hg for 10 minutes or more.

1 Includes Intraoperative death.

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tients who had elective aneurysm repair with those who five-fold increase in perioperative myocardial infarction underwent emergency operation with intact aneurysms, (15 percent) among the patients with intact aneurysms there were no significant differences in time required for undergoing emergency operations in comparison to those mechanical ventilation, time spent in the intensive care having elective operations underscores this point. In an unit, and length of hospitalization. Patients with ruptured attempt to reduce both morbidity and mortality rates, aneurysms who survived operation had complicated post- some investigators have advocated tests to differentiate operative courses. Ninety-five percent of patients with intact from ruptured aneurysms in stable patients so that ruptured aneurysms had postoperative morbidity in com- only those with rupture undergo emergency operation. parison to 38 percent of patients undergoing emergency Johnson et al [5] recommended using blood pressure (less operation with intact aneurysms and 38 percent of those than I00 mm Hg) and hematocrit value (less than 37 having elective operation. Although there were no signifi- percent) to determine rupture. In applying these criteria, cant differences in total morbidity among patients having only 70 percent of our patients with rupture would have em%rgency operation with intact aneurysm and elective been identified. Furthermore, several patients with intact patients, the incidence of perioperative myocardial in- aneurysms satisfied these criteria. We found that careful farction was five times greater in the former group. Myo- assessment of posturally induced hemodynamic changes cardial infarction occurred in 15 percent of emergency (tilt test) was more helpful. However, this test was inconpatients with intact aneurysms, 13 percent of patients sistently applied, and it would be misleading to recomwith ruptured aneurysms, and 3 percent of patients hav- mend this maneuver as a reliable test to discern rupture. ing elective repair. The 30-day operative mortality rate Hemodynamic changes and a low hematocrit value may among patients with elective operations was 5 percent. rightfully increase the index ofsuspicion that a symptomFor patients undergoing emergency operation with intact atic aneurysm is ruptured, but the absence of such findaneurysms, the mortality rate was 3 percent, which was ings does not exclude the presence of rupture. much lower than the rate in those with ruptured aneu- 9 Recently, some have advocated the routine use of rysms (68 percent; p <0.01) but not significantly differ- computerized tomography in symptomatic patients who ent from the rate in those having elective operation. are stable [1,2]. The purported advantages include the reliable differentiation of ruptured and intact aneurysms, COMMENTS the disclosure of other intraabdominal pathologic abnorSeveral investigators have noted that the mortality malities that may be mimicking signs and symptoms of rate from emergency operations on patients with symp- rupture, and an overall reduction in operative morbidity tomatic, intact aneurysms has been excessive (range 14 to and mortality by selecting only patients with rupture for 25 percent, mean 16 percent) [3-7]. The reasons for the emergency operation. Johnson et al [2] were the first to high rate in these patients is unclear. The most commonly report the use of computerized tomography in this setcited reason is that emergency operation precludes ade- ting. They retrospectively analyzed 57 symptomatic paquate preoperative preparation. However, many have tients, of whom only 6 (10 percent) had ruptured aneunoted excessive operative mortality among these patients, rysms. Computerized tomography results suggested even when standard preoperative preparation was carried rupture in 12 patients, thus giving a false-positive rate of out. Among 131 patients with intact aneurysms and pain 50 percent. These patients had emergency operation and tenderness, Crawford et al [4] noted that the opera- (mortality rate 25 percent). In seven patients, computertive mortality (8 percent) was twice as high in comparison ized tomography disclosed an intact but unstable aneuto patients with no symptoms. In a smaller series, Chang rysm (recent increase in size, focal discontinuity of calciet al [3] also noted that the operative mortality rate of fied rim, and other nonspecific radiologic signs). These symptomatic patients (13 percent) was two times higher patients had urgent operation performed within 24 to 48 than that of asymptomatic patients. Most recently, John- hours of admission (mortality rate 14 percent). The invesson et al [2] reported using computerized tomography to tigators noted that no patient with an intact aneurysm differentiate intact from ruptured aneurysms in symp- ruptured during the delay imposed by computerized totomatic patients to spare those with intact aneurysms mography; however, they had one patient who rapidly emergency operation. Despite adequate preoperative exsanguinated after the scan showed a Confined rupture. preparation, the operative mortality among these patients The potential for delayed operation in patients with was in excess of 7 percent. In most series, patients with ruptured aneurysms and the risk of rupture in symptomsymptomatic, intact aneurysms are older and have more atic patients with intact aneurysms who are undergoing a risk factors for major surgery than patients undergoing period of evaluation and preparation for urgent operation elective operations, and it is probable that many ot" these are of great concern [8-10]. In our series, the mean time patients would not have been considered for elective sur- interval between admission and operation was 6 hours for gery had they remained asymptomatic. patients with ruptured and intact aneurysms. Most of this Our results compare favorably with other series of delay was engendered by inexperience on the part of the patients with symptomatic, intact aneurysms undergoing examining physicians in the emergency room. Because of emergency or semielective operation. Our series is more lack of recognition of the condition, many diagnostic tests recent, and the lower mortality may reflect contemporary and radiographs were obtained before surgical consultastandards and improvements in care. That is not to say tion was sought. Despite a vigorous campaign to educate that these patients would not have benefited from more physicians in the emergency room, inappropriate delays thorough preoperative evaluation and preparation. The for diagnostic tests still occur regularly. We suspect that 472

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this situation is common, particularly in large teaching institutions with frequent turnover of physicians in the emergency room. To add further delay by obtaining a computerized tomography scan would, in our opinion, expose patients to excessive risk. The clinical course of patients with symptomatic aneurysms is notoriously unpredictable [8,9]. Every surgeon with experience in this area has had patients who were seemingly stable who suddenly "crash." Lawrie et al [11] noted that 10 of 44 patients with ruptured aneurysms (23 percent) developed hypotension after admission to the hospital. Many investigators have noted that preoperative hypotension is associated with a high mortality rate. Wakefield et al [12], in a multivariate study of death from ruptured aneurysms, found significantly increased intraoperative and postoperative mortality rates associated with the development of preoperative hypotension (39 percent and 78 percent, respectively). Our results would not have been substantially improved by the routine use of computerized tomography scanning. It is possible that some of the six patients with other intraabdominal abnormalities would have been identified and more appropriately managed. It is also possible that the incidence of perioperative myocardial infarction might have been reduced because of better preoperative evaluation and preparation in some patients. Because it is expensive and delays emergency operation in patients who actually have ruptured aneurysms, computerized tomography seems rarely indicated in symptomatic patients with obvious aneurysms. In patients in whom the diagnosis of aneurysm is uncertain (for example, obese patients), in those with small aneurysms, and in those with atypical symptoms, computerized tomography scanning may be helpful. REFERENCES 1. Lineaweaver WC, Clore F, Alexander RH. Computed tomographic diagnosisof acute aortoiliaccatastrophes.Arch Surg 1982; 117: 1095-7. 2. Johnson WC, Gerzof SG, Nabseth DC. The role of computed tomographyin symptomaticaortic aneurysms.Surg GynecolObstet 1986; 162: 49-53. 3. Chang FC, Smith JL, Rahbar A, Farha GJ. Abdominalaortic aneurysms.A comparativeanalysisof surgical treatment of symptomatic and asymptomaticpatients. Am J Surg 1978; 136: 705-8, 4. Crawford ES, Saleh SA, Babb JW, et al. Infrarenal abdominal aortic aneurysm. Factors influencingsurvival after operation performed over a 25-year period. Ann Surg 1981; 193: 699-709. 5. JohnsonG, McDevittNB, Proctor HJ, MandelSR, PeacockJB. Emergent or electiveoperation for symptomaticabdominalaortic aneurysm. Arch Surg 1980; 115: 51-3. 6. McCabe CJ, Coleman WS, Brewster DC. The advantage of early operation for abdominalaortic aneurysm.Arch Surg 1981; 116: 1025-9. 7. Soreide O, LillestolJ, Christensen O, et al. Abdominal aortic aneurysms: survival analysisof four hundred thirty-four patients. Surgery 1982; 91: 188-93. 8. Gaylis H, Kessler E. Ruptured aortic aneurysms.Surgery 1980; 87: 300-4. 9. Hiatt JCG, BarkerWF, MachlederHI, BakerJD, BusuttilDW, Moore WS. Determinantsof failure in the treatment of ruptured abdominal aortic aneurysm.Arch Surg 1984; 119: 1264-8.

10. Ottinger LW. Ruptured arterioscleroticaneurysmsof the abdominal aorta. JAMA 1975; 233: 147-50. 11. LawrieGM, Morris GC, Crawford ES, et al. Improvedresults of operation for ruptured abdominal aortic aneurysms. Surgery 1979; 85: 483-8. 12. WakefieldTW, WhitehouseWM, Wu S-C, et al. Abdominal aortic aneurysm rupture: statistical analysis of factors affecting outcome of surgical treatment. Surgery 1982; 91: 586-96. DISCUSSION M. Alex Jaeoeks (Oklahoma City, OK): Dr. Buss, do you routinely use Swan-Ganz monitoring and hemodynamic pharmacologic management in patients undergoing aneurysm repair, and how do you propose to lower that 15 percent perioperative myocardial infarction rate? You did perform abdominal radiography on all patients, which Loughran from Liverpool recently reported to have as much as a 90 percent sensitivity for diagnosing ruptured aneurysms, and you did perform abdominal ultrasonography on 21 of your patients. Did these preoper ative diagnostic aids help identify ruptured aneurysms in your group? Do you have any other suggestions regardifig the timely diagnosis of aneurysm rupture? Ernest Poulos (Dallas, TX): We have tried to get our radiologists to establish ultrasonography for use in the emergency room to help diagnose patients who have abdominal pain with an occult source. This would help screen patients who are hurting but have not ruptured. This is a category you have described in which the intact aneurysm mortality rate is much lower than that of frank rupture. Dominie Albo (Salt Lake City, UT): What you do when you operate on patients who you think have ruptured aneurysms who, indeed, have an aneurysm that is ruptured but have, in addition, pathologic abnormalities such as acute cholecystitis, diverticulitis, and so on? Do you correct both conditions at the same operation? Randall W. Buss (closing): We routinely use SwanGanz monitoring. The KUB and ultrasonography did help to identify the aneurysms, but we did not find that they helped to identify or determine if the patient did indeed have a ruptured aneurysm. Dr. Poulos, I agree that ultrasonography is very useful in patients, and it can be performed in the emergency room and the findings rapidly obtained. I also agree that if computerized tomography could be rapidly carried out and read, it could be useful in a patient in whom it is not clear whether or not the aneurysm has ruptured. Dr. Albo, we would proceed with the cholecystectomy first and then stage the patient at a later date to undergo aneurysm surgery. Dr. Jacocks, in order to decrease the 15 percent myocardial infarction rate, I think it would be useful to be able to determine which patients are ruptured and which ones are not because then those patients who were could undergo more complete preoperative assessment, including cardiology evaluation and, possibly, catheterization.

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