Ruptured abdominal aortic aneurysm: factors influencing operative mortality

Of fifty-eight consecutive patients surgically treated for aneurysm of the abdominal aorta, twenty were emergency cases following the rupture. Associated diseases were found in 85 per cent of patients; hypertension being the most common. Fifty per cent of patients were in shock on admission. The duration between rupture and operation was three hrs to two weeks with the average of 115.5 hrs. In six patients, the diagnosis of abdominal aortic aneurysm was known for over six months. The operative mortality rate in case of ruptured abdominal aortic aneurysm was 45 per cent. The most important determinants of survival were the incidence of shock on admission, the incidence of associated disease, the known duration of the aneurysm, and the time interval from rupture to admission. The intraoperative factors most influencing survival were the type of rupture, intraoperative hypotension, and total blood loss. Comparison of the mortality rate in elective surgery of abdominal aortic aneurysms (5.3 per cent) with that in ruptured aneurysms (45.0 per cent) suggests the necessity for early elective operations whenever abdominal aortic aneurysms are diagnosed.     

Ruptured abdominal aortic aneurysm. Treatment and review of eighty-seven patients

Between 1954 and 1973 at the Texas Heart Institute, eighty-seven patients underwent operation for resection of ruptured abdominal aortic aneurysms. Included in this series were eighty-one men and six women who ranged in age from forty-four to eighty-four years. Hospital mortality, including intra- and postoperative mortality (within thirty days of operation), was 21 per cent. Mortality for men was 19.8 per cent and for women, 33.3 per cent.The lower mortality indicates that abdominal aortic aneurysms should be excised electively. When rupture does occur, aggressive surgical treatment can produce gratifying results.     

Ruptured abdominal aortic aneurysm: Factors influencing operative mortality

Of fifty-eight consecutive patients surgically treated for aneurysm of the abdominal aorta, twenty were emergency cases following the rupture. Associated diseases were found in 85 per cent of patients; hypertension being the most common. Fifty per cent of patients were in shock on admission. The duration between rupture and operation was three hrs to two weeks with the average of 115.5 hrs. In six patients, the diagnosis of abdominal aortic aneurysm was known for over six months. The operative mortality rate in case of ruptured abdominal aortic aneurysm was 45 per cent. The most important determinants of survival were the incidence of shock on admission, the incidence of associated disease, the known duration of the aneurysm, and the time interval from rupture to admission. The intraoperative factors most influencing survival were the type of rupture, intraoperative hypotension, and total blood loss. Comparison of the mortality rate in elective surgery of abdominal aortic aneurysms (5.3 per cent) with that in ruptured aneurysms (45.0 per cent) suggests the necessity for early elective operations whenever abdominal aortic aneurysms are diagnosed. Presented at the Fifteenth Annual Meeting of the Japanese Association for Cardiovascular Surgery, Kanazawa, Japan, May 17–18, 1985.     

Abdominal aortic aneurysms in Western Australia: descriptive epidemiology and patterns of rupture

All abdominal aortic aneurysms presenting to hospitals and coroners in Western Australia over an 11-year period (January 1971 to December 1981) have been reviewed. A total of 1237 abdominal aortic aneurysms were found. After age and sex standardization it was apparent that the prevalence of diagnosis of abdominal aortic aneurysms had increased from 74.8 per 100 000 to 117.2 per 100 000 for men over 55 years of age (increase of 56.7 per cent) and from 17.5 per 100 000 to 33.9 per 100 000 for women over 55 years of age (increase of 93.7 per cent) during this period. One hundred and twenty-three patients were identified by coroner's autopsy after sudden death from ruptured abdominal aortic aneurysms in whom there had been no previous diagnosis of abdominal aortic aneurysm. Between 1971 to 1981, 478 patients underwent surgery; 225 had elective resection of their aneurysm with a 4.0 per cent fatality rate, and 253 had emergency operations with a 31.2 per cent fatality rate. Seasonal variations contributing to the date of emergency presentation or death from rupture of abdominal aortic aneurysms indicated a possible influence of colder weather upon rupture. It is hoped that the information provided in this paper will be of use to surgeons and physicians involved in health care planning for similar populations.     

RUPTURED ABDOMINAL AORTIC ANEURYSM: LONG-TERM SURVIVAL AFTER OPERATION

The long-term follow-up of 65 patients surviving surgery for ruptured abdominal aortic aneurysms is presented. Fifty-six per cent of these patients were alive at the time of review, having survived for a mean period of 36 months. The majority were enjoying a quality of life similar to that experienced before operation. Preexisting ischaemic heart disease did not alter the long-term prognosis. Cumulative survival curves for this group of surivivors approximated both the survival curve for the average matched Australian population and similar curves constructed for patients operated upon electively for abdominal aortic aneurysms.     

Abdominal aortic aneurysms: should they all be resected?

A retrospective study has been carried out on 124 consecutive patients with abdominal aortic aneurysms admitted during the period 1960-74. The mortality rate after emergency operation was 56 per cent and after elective operation 15 per cent. As in other vascular centres during these years the mortality rate has decreased among electively operated patients. We have tried to answer two questions: which patients without signs of rupture should undergo operation and which patients with a ruptured aneurysm should not be operated upon?     

Impact of vascular surgery on community mortality from ruptured aortic aneurysms

The workload of aortic surgery in a district increased fourfold over 10 years as the incidence of aneurysm rupture rose from 7 to 17/100,000. Of 260 patients with ruptured aneurysms 101 reached hospital alive (38 per cent) of which 52 (52 per cent) survived, an overall survival rate of 19.8 per cent. Despite increasing experience, mortality after emergency surgery did not improve, suggesting outcome was largely determined by the patient's condition and age. Only 5 of 90 patients aged over 75 survived aortic rupture at home. In consequence overall community mortality did not improve in the period studied. Survival after elective surgery was 95 per cent, suggesting that efforts to improve survival should be directed towards identifying and treating the disease before rupture occurs. The commonly stated figure of 50 per cent survival for ruptured aortic aneurysms is an overestimate, due to neglect of patients dying at home.     

An evaluation of new methods of expressing aortic aneurysm size: relationship to rupture.

The diameter of aortic aneurysms were standardized to measures of patient size and normal aortic size in an effort to define indexes that might be more predictive of aneurysm rupture than raw aneurysm diameter alone. Normal aortic diameters were measured in 100 patients undergoing abdominal CT scans for other reasons, and an average infrarenal aortic diameter of 2.10 +/- 0.05 cm was observed. Normal aortic diameter was dependent on both age and sex, ranging from 1.71 +/- 0.06 cm in women below age 40 years to 2.85 +/- 0.04 cm in men above age 70 years. Overall, 11 (5.1%) of the ruptures occurred in aneurysms less than 5 cm in diameter, and four (1.9%) occurred in aneurysms less than 4.0 cm in diameter. When the CT scans of 100 patients undergoing elective aneurysm resection were compared with those of 36 patients with ruptured aneurysms, no threshold diameter value accurately discriminated between the two groups. However, standardization of the aneurysm diameter to the transverse diameter of the third lumbar vertebral body as an index of patient body size produced an accurate predictor of rupture when a threshold ratio of 1.0 was used. No aneurysm ruptured below this ratio, but 29% of elective aneurysms were smaller than the vertebral body diameter. Receiver operating characteristic curve analysis confirmed the superiority of the aneurysm to vertebral body diameter ratio as a discriminator of ruptured aneurysms. It appears that aneurysm diameter alone is not sufficiently predictive of rupture to be used as the sole indication for elective resection.     

Problems in the diagnosis and treatment of abdominal aortic aneurysms

Experience with surgery for abdominal aortic aneurysms in a growing community of transients and retirees suggests that the diagnosis of aneurysm is being delayed and that surgery is recommended late. Pain or a pulsating mass was found in all patients when seen in surgical consultation, yet the diagnosis was first made by roentgenogram in 38 per cent of the patients with nonruptured aneurysms. The significance of pain and the need to examine carefully the abdomen of elderly patients are emphasized. Late diagnosis or concern over the risks of surgery caused a delay of over four months in the surgical treatment of one third the patients. The 39 per cent incidence of rupture could have been decreased by earlier diagnosis and recommendation for surgery. Pulmonary and cardiac complications remain a problem in these elderly patients. Mortality has been lowered to 7.4 per cent for elective surgery and 34 per cent for emergency surgery for ruptured aneurysm by paying closer attention to complications and by shortening the surgical procedure.     

Prevention of distal embolism during arterial reconstruction

Distal embolization of fragmented laminated thrombus and atheroma producing peripheral ischemia or gangrene is an underemphasized complication of arterial reconstruction. A set of techniques has been developed to minimize this important complication. To assess their effectiveness, the incidence of distal embolism in patients undergoing resection of abdominal aortic aneurysm with and without the use of these techniques was studied. In the 434 patients who underwent elective resection of abdominal aneurysm, measures to prevent distal embolism were used in all cases. The incidence of distal embolism was only 0.23 per cent (1 of 434), in contrast to reported incidences of up to 11 per cent. In the 21 patients who underwent emergency resection of ruptured aneurysm, these techniques were not used due to the need for early proximal control for resuscitation; distal embolism of atheromatous material occurred in 2 cases, an incidence of 9 per cent. The application of these techniques to other peripheral vascular procedures has resulted in similar low rates of postoperative distal ischemia.     

Abdominal aortic aneurysm in elderly patients: Selective management based on clinical status and aneurysmal expansion rate

The records of 125 patients 75 years of age or older with a diagnosis of unruptured abdominal aortic aneurysm were reviewed. Operative mortality was 4.3 percent in 69 patients considered at low risk and 39.8 percent in 13 patients at high risk who underwent aneurysmectomy shortly after diagnosis. Forty-three patients with an asymptomatic abdominal aortic aneurysm initially measuring 3.5 to 6 cm did not undergo aneurysmal resection and were followed for 6 to 72 months (mean 24 months) with serial echography. The mean enlargement rate was 0.48 cm/year. In the 43 patients, resection of the abdominal aortic aneurysm was performed for aneurysmal expansion to greater than 6 cm, development of symptoms, or a sudden change in aneurysmal diameter. Two patients were lost to follow-up, 21 underwent elective resection, aneurysms ruptured in 2, 9 died from other causes, and 9 were alive and asymptomatic at last follow-up. An aggressive surgical approach seems appropriate, even in the asymptomatic elderly patient with a small aneurysm of 4.5 to 6 cm. Serial echographic measurement appears useful in determining which patients with a very small aneurysm of less than 4.5 cm or who are considered to be high risk surgical candidates require elective aneurysmectomy.     

Early and mid-term results of endovascular stent grafting for aortic aneurysms]

Early and mid-term clinical results of 28 cases of endovascular stent grafting for descending thoracic aortic aneurysms and 11 cases of abdominal aortic aneurysms are reported. Early clinical results: Among 28 patients (7 true thoracic aortic aneurysms, 3 pseudothoracic aortic aneurysms and 8 acute, 4 subacute, and 6 chronic aortic dissections), two patients (7.1%) with ruptured acute aortic dissection or ruptured infected pseudoaneurysm died in the perioperative period. Two of the remaining 26 patients experienced minor complications. Aneurysmal sacs or false lumens at the descending thoracic aorta were completely thrombosed in the 26 patients. One patient (9.1%) with a ruptured abdominal aneurysm died, and one of the remaining 10 patients had renal and peripheral emboli and peripheral vascular trauma. Inadvertent covering of the renal arteries occurred in another patient. Unless one patient had persistent endoleak, aneurysmal sacs in the 10 surviving patients were thrombosed. Mid-term clinical results: One aortic dissection at a different section of the descending aorta occurred 6 months after stent grafting for aortic dissection, and one patient died of pneumonia 3 months after stent grafting for an abdominal aortic aneurysm. CT scanning 6 months after stent grafting revealed a decrease in maximal aneurysmal size in 3 of 9 patients with true or pseudothoracic aneurysms and in 2 of 5 patients with abdominal aortic aneurysms. Five of 9 patients with stent grafting for acute or subacute dissection showed elimination of the false lumen in the descending thoracic aorta in a CT scan 6 months after grafting. One patient with a true thoracic aneurysm and one patient with an abdominal aortic aneurysm showed an increase in aneurysmal size in a CT scan 2 years and one year after treatment, respectively.     

Aneurysm of the infrarenal abdominal aorta

Preoperative and postoperative treatment as well as standardisation of surgical techniques over the past 20 years have helped to bring about considerable reduction of operative mortality in cases of asymptomatic aortic aneurysm. Yet, with all improvement, rupture of aneurysm has continued to be associated with high rates of mortality. At the Department of Surgery of Cologne University, between 1963 and 1985, operations were performed on 681 patients for abdominal aortic aneurysm. Asymptomatic aneurysm were surgically removed from 41.7 per cent of them, while 27.5 per cent underwent surgery in symptomatic stages. Aneurysm had ruptured in 210 patients. Operative mortality accounted for 5.3 per cent of all asymptomatic patients. High mortality rates among patients with ruptured aortic aneurysms were attributable to preoperative shock. Only 16.3 per cent of patients survived in this group. The mortality rate among patients without shock amounted to 39.5 per cent.     

Surgical treatment of the aortic aneursysm

For 93 cases of thoracic and 118 cases of abdominal aneurysms, the over-all operative mortality rate was 24.7 per cent and 9.3 per cent, respectively. Although the over-all operative mortality rate for 37 patients with aneurysms of the ascending aorta or aortic arch had been 40.5 per cent, recent advances in surgical technique led to a higher survival rate so that since 1975 no death occurred among 14 consecutive surgery cases. Cardiopulmonary bypass with or without selective perfusion of the carotid arteries or temporary external bypass procedures were employed in these 14 cases. The over-all operative mortality rate for 56 patients with aneurysms of the descending thoracic aorta was 14.3 per cent. Temporary external bypass prodedures were employed in 49 cases. The operative mortality rate for 99 patients with unruptured abdominal aneurysms was five per cent, and that for 19 patients with ruptured aneurysms was 31.5 per cent.     

Surgical treatment of the aortic aneurysm

For 93 cases of thoracic and 118 cases of abdominal aneurysms, the over-all operative mortality rate was 24.7 per cent and 9.3 per cent, respectively. Although the over-all operative mortality rate for 37 patients with aneurysms of the ascending aorta or aortic arch had been 40.5 per cent, recent advances in surgical technique led to a higher survival rate so that since 1975 no death occurred among 14 consecutive surgery cases. Cardiopulmonary bypass with or without selective perfusion of the carotid arteries or temporary external bypass procedures were employed in these 14 cases. The over-all operative mortality rate for 56 patients with aneurysms of the descending thoracic aorta was 14.3 per cent. Temporary external bypass procedures were employed in 49 cases. The operative mortality rate for 99 patients with unruptured abdominal aneurysms was five per cent, and that for 19 patients with ruptured aneurysms was 31.5 per cent.     

Emergency operation in patients with symptomatic abdominal aortic aneurysms

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 retrospective 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 these 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.     

Technical aspects in the management of abdominal aortic aneurysms

During the past decade, resection of abdominal aortic aneurysms has become common. The technical aspects of the operation are now relatively standardized and simplified. With concomitant improvements in anesthesia and intensive care, the operative mortality for elective resection of these aneurysms has declined progressively; several centres report an operative mortality of less than 5%. The author considers the following principles important in managing patients with abdominal aortic aneurysms: (a) simplicity and limited dissection are critical features of the operative technique; (b) tubular grafts should be used whenever possible; (c) selected patients should be transferred to the intensive care unit preoperatively for "fine-tuning" of the cardiovascular system; (d) patients should be monitored intraoperatively and postoperatively; (e) the surgeon should be aware of special problems such as horseshoe kidney, venous anomalies, adherent duodenum and the presence of major arteries arising from the aneurysm; (f) ruptured aneurysms should be diagnosed promptly and the patient operated upon without delay. Using these principles, the author's group achieved an operative mortality of only 1.8% in 168 patients with abdominal aortic aneurysms resected electively. However, the operative mortality for their patients with ruptured aortic aneurysms was 50%, a rate that has not changed appreciably over the years.     

Abdominal aortic aneurysm as an incidental finding in abdominal ultrasonography

The difference between the mortality rate from ruptured abdominal aortic aneurysm (overall mortality rate 85-95 per cent and operative mortality rate 23-63 per cent), and that for elective aneurysm repair (less than 5 per cent) is dramatic. Awareness of the existence of an abdominal aortic aneurysm is therefore essential. Of 1800 consecutive patients aged greater than or equal to 50 years referred for their first abdominal ultrasonography, 113 who had been referred specifically for suspected abdominal aortic aneurysm or vascular screening were excluded. The remaining 1687 patients (693 men and 994 women) form the study group. Apart from the symptom-directed examination, the entire abdomen of every patient was routinely studied by ultrasonography. The definition of an abdominal aortic aneurysm was a local dilatation of the aorta with an anteroposterior diameter greater than 30 mm or greater than 1.5 times the anteroposterior diameter of the proximal aorta. In 82 cases (4.9 per cent) an abdominal aortic aneurysm was disclosed; 61 were in men (8.8 per cent) and 21 were in women (2.1 per cent). The prevalence of abdominal aortic aneurysm as an incidental finding in men aged greater than or equal to 60 years was 11.4 per cent. In every patient aged greater than or equal to 50 years undergoing their first abdominal ultrasonography examination, the aorta should be screened for the presence of an aneurysm.     

Cryptic mycotic abdominal aortic aneurysms: diagnosis and management

The incidence of cryptic mycotic abdominal aortic aneurysms has relatively increased since antibiotic therapy has become available. The causative organism is the salmonella group in about 50 per cent of cases. This diagnosis should be strongly entertained in patients with fever of unknown origin, vague abdominal pain, and progressive appearance of a pulsatile abdominal mass. Aortography may be helpful in establishing the diagnosis. Some postoperative graft infections may be due to unrecognized cryptic mycotic infection of the aorta and not from external contamination, as previously supposed. Construction of an axillofemoral bypass graft through clean tissue is advised for the successful treatment of the grossly infected infrarenal aortic aneurysm. Three surviving patients with cryptic mycotic abdominal aortic aneurysms are added to the sixteen surviving patients already reported in the literature.     

Infrarenal aortic aneurysms. Asymptomatic versus symptomatic

Between 1978 and 1983, 103 patients underwent operations for infrarenal abdominal aortic aneurysms (AAA). Fifty-seven patients (group I) had elective procedures without a death and with a morbidity of 19 per cent. Thirty-three patients (group II) had symptomatic but nonruptured AAA, while 13 patients (group III) had ruptured AAA. In group II, the mortality was 6 per cent and in group III, 37 per cent, while the morbidity was 33 and 100 per cent, respectively. There was no morbidity or mortality from pulmonary emboli, as all patients had prophylactic inferior vena cava interruption at the time of operation for their AAA. These results substantiate the necessity for early and aggressive treatment in patients with AAA, as the mortality and morbidity, once symptoms develop, remain prohibitive.