Annals of the Royal College of Surgeons of England (1983) vol. 65 ASPECTS OF TREATMENT* Unoperated Abdominal Aortic Aneurysm: Presentation and Natural History E. M. WALKER FRC'S Senior Registrar B. R. HOPKINSON FRCS Consultant Surgeon G. S. MAKIN FRCS Consultant Surgeon University Hospital Nottingham Key words: ABDOMINAL AORTIC ANEURYSM; RUPTURE; GRAFT; ELECTIVE OPERATION Summary The natural history of abdominal aortic aneurysm (AAA) is death from rupture unless the patient diesfrom another cause prior to rupture. Elective aortic grafting is the treatment of choice. Following rupture, emergency operation is the only treatment which will prolong the patient's survival. Controversy still exists as to the optimum management in poor risk patients and in those with a small aneurysm. This paper describes the presentation and natural history of 65 patientis presenting with a ruptured abdominal aortic aneurysm who did not have an emergency operation, and afurther 27 patients in whom the diagnosis of intact AAA was made who did not have an elective aortic replacement graft. The correct diagnosis was made at the time of admission in only 43 of the 65 patients with ruptured aneurysms. The diagnostic errors and appropriate investigations in cases of doubt are discussed. The mean time from admission to hospital to death was 8 hours. The reasons for not performing an elective operation in the 27 patients known to have AAA are given. .Nine have subsequently died from rupture. There have been 7 deaths from other causes. Clinical experience The incidence of intact abdominal aortic aneurysm (AAA) found at autopsy is approximately 2°o (1). The natural history of AAA is death from rupture unless the patient dies from other causes prior to rupture. Most clinical studies of patients with unoperated AAA cite a 30-60% incidence of rupture (2-5), McGregor (6) reported 41 deaths from ruptured AAA in 9894 consecutive autopsies (0.41o ). Despite recent advances in the treatment of patients with AAA the mortality is still 40-600o in those patients operated on after rupture (4, 7). In contrast the mortality following elective resection is 2-50O (8). In poor risk patients or those with small aneurysms controversy still exists as to the optimum management. In addition there is a small group of patients who will not accept an operation. Accurate diagnosis is an essential pre-requisite to early operation. In a retrospective study of 42 ruptured AAA 15 died without the diagnosis being suspected, and in only half the remainder was the correct diagnosis made at the time of admission to hospital (9). This paper presents details of 65 patients presenting with ruptured AAA and the natural history of a further 27 patients in whom the diagnosis of AAA had been confirmed but who did not have an elective operation. GROUP I 65 PATIENTS PRESENTING WITH RUPTURED ABDOMINAL AORTIC ANEURYSM AND NOT UNDERGOING SURGERY Sixty-five patients presented to hospital during the period 1971-81 and subsequently died from ruptured AAA without undergoing aortic graft replacement. During the same period, a further 68 patients were operated on for ruptured AAA. Of the 65 patients who did not have a graft 53 were male and 12 female, age range 51-88 years. Table 1 details the principle presenting symptoms in the 65 patients. Abdominal pain and circulatory collapse were the two most common presenting symptoms. Back pain was not a common feature, and no patient presented with lower limb ischaemic pain. In only 16 was the classical triad of circulatory collapse, abdominal pain, and an expansile abdominal swelling present. Thirteen of the patients had a systolic blood pressure above 100mm/Hg, and in 23 the systolic pressure was below 70 mm/Hg. In 43 the correct diagnosis was made at the time of admission, of whom 6 were previously known to have an aneurysm. Two had previously refused elective operation, and 4 had been refused on the grounds of age (82-85 years). In all but 6 patients some abdominal tenderness was elicited, TABLE I Presenting symptoms in 65 patients with ruptured aortic aneurysm Circulatory collapse Abdominal pain Back pain Vomiting Shortness of breath Chest pain Renal failure The Editor would welcome any comments on this paper by readers Fellows and Members interested in submitting papers for consideration for publication should first write to the Editor * 35 34 4 5 2 I I E Al Walker, B R Hopkinson and G S Makin 312 but an expansile abdominal mass was only felt in 29. The reason for no operation being performed in the 43 patients in whom the correct diagnosis had been made are given in Table II. The 2 patients previously known to have an aortic aneurysm who had refused elective operation also refused an emergency operation. The most common reason for refusal of emergency surgery was age. Many of these patients had a previous history of cardiovascular disease. The list of erroneous diagnosis which were confused with ruptured AAA is shown in Table III. In the patient with renal failure and ischaemic colitis, AAA was the underlying cause of these conditions, but was unrecognised at the time. TABLE II Reasons for no operation in patients with the correct diagnosis of ruptured aneurysm Age Died awaiting emergency operation Died on induction of anaesthetic Possible dissecting aneurysm Congestive cardiac failure Renal failure Earlier elective operation aborted Not recorded Patient refused operation 22 3 3 2 3 Range 76-88 I I 6 2 TABLE IV Reasons for no definitive operation bein, performed in patients known to have an intact abdominal aortic aneurysm Age Congestive cardiac failure Patient refused operation Operation aborted Small aneurysm Multiple medical problems Known carcinoma of stomach 12 5 4 4 2 2 I grafted. The fourth patient also had an inflammatory sugaricing aneurysm in which the inferior vena cava and the left renal vein were incorporated in the dense inflammatory tissue surrounding the aneurysm. Nine of these 27 patients have subsequently died from rupture of their aneurysm. The time from diagnosis to rupture varied from 3 months to 6 years (mean 21 months). Six patients have died from causes unrelated to their aneurysm and in 1 the cause of death was unknown. Four patients have been lost to follow up and 7 remain alive, 3 of whom have survived more than 6 years since the diagnosis was made. Of these 3, 2 are the patients with inflammatory aneurysms, and the third has persistently refused operation despite the fact that his aneurysm has slowly been getting larger for 8 years. TABLE iII Diagnoses confused with ruptured aortic aneurysm Myocardial infarction Carcinoma of stomach Abdominal tumour Mesenteric infarction Cerebrovascular accident Renal failure Renal failure and ischaemic colitis Diverticular disease Congestive cardiac failure Gastro-intestinal tract bleeding Chronic bronchitis Perforated duodenal ulcer Ureteric colic No diagnosis made 4 2 I I I I I I I I I I I 5 In one of the patients diagnosed as having carcinoma of the stomach, this diagnosis was confirmed at post-mortem in addition to his undiagnosed ruptured AAA. In the 3 patients diagnosed as having mesenteric infarction, gastro-intestinal bleeding and perforated duodenal ulcer, surgery might have been undertaken, but none of the patients was referred to a surgeon. GROUP 2 27 PATIENTS WITH INTACT AORTIC ANEURYSM WHO DID NOT HAVE AN OPERATION In 27 patients a diagnosis of intact AAA was made in whom elective operation was not performed. The most common presentations in these patients were abdominal pain (7), abdominal mass (6), and back pain (3). Seven were found on routine clinical examination in patients presenting with unrelated symptoms. The reason for elective operation not being performed in these patients is shown in Table IV. Age was again the most common reason for refusal (range 77 to 90 years). In 2 the aneurysm was considered too small to warrant operation but one of these died 2 years later from rupture. In 4 more patients in whom an operation was attempted and abandoned 1 had multiple congenital venous anomalies, including a bilateral vena cava. In 1 the aneurysm was thought to involve the renal arteries, but adhesions from a previous gastrectomy prevented full dissection. One patient presented with bilateral hydronephrosis due to retroperitoneal fibrosis. His ureters were freed but the aneurysm which was of the inflammatory sugar-icing type, was not Discussion There must always be some limitations on the conclusions drawni from retrospective studies, but we believe this study shows some interesting and important aspects of AAA. Mortality following rupture of an AAA is so high that no properly controlled trial of operation versus conservative management of AAA either ruptured or intact is possible. Of the 23 patients in whom follow up is available, and are known to have had an aneurysm managed conservatively 8 (35%/) died from rupture within 3 years. Darling (2) from a series of 16483 consecutive autopsies reported 83 deaths from ruptured AAA (0.50/), and intact AAA in 199 patients dying from other causes (1.20o) indicating that fewer than 300, of patients with an AAA died from rupture. Very few of the patients in this series were known to have an aneurysm prior to death, and no mention is made of the number who had had an elective operation for their aneurysm. The mean time from diagnosis to death in the present series of ruptured AAA in whom the correct diagnosis was made was 8 hours, excluding 3 patients who survived more than 24 hours. Thus ample time was available to assess the fitness for operation in the patient with ruptured AAA. The diagnosis of ruptured AAA is often difficult. In the 16 patients presenting with the classical triad of circulatory collapse, abdominal pain and an expansile abdominal mass the diagnosis was made without difficulty. Circulatory collapse may be due to many causes, but in elderly men careful examination of the abdomen is imperative. An abdominal mass was not felt in over half the patients. This may be due to obesity, guarding of the abdominal musculature, or leakage from a small aneurysm. Some abdominal tenderniess was almost always present. The lack of tamponade provided by the retroperitoneal structures when the rupture is into the peritoneal cavity, usually results in such profound shock that the patients do not reach hospital alive, but abdominal distention due to haemoperitoneum may produce tenderness with no palpable mass. Only 3 patients died before emergency operation could be performed, and in the 22 in whom the wrong diagnosis or no diagnosis was made, 19 survived more than 2 hours. Ample time was therefore available for plain abdominal x-ray or ultrasound examination which might have helped in making the diagnosis (10). Linoperated abdominal aortic aneurysm Janover (11) found that in 18 out of 20 patients with ruptured AAA the radiographs were diagnostic. The lateral views of the abdomen are the most valuable, but unless the possibility of an aneurysm is borne in mind, the radiographs may be misinterpreted. The more important radiographic findings in cases of ruptured aneurysm include obliteration of the psoas shadow, hazy and indistinct margin of the mass with extension beyond the calcified rim, and displacement of the bowel gas anteriorly on the lateral film. The list of diagnostic errors made in the patients with ruptured AAA is similar to that reported elsewhere (6, 9). A high index of suspicion is essential if the diagnosis is not to be missed. In the 27 patients knowin to have an intact AAA who did not have an elective operation, the most common reason was again age (440w). Chang et al. (12) reported a mortality of 1400 in patients undergoing elective operation for AAA over the age of 70 compared with 4.800 for patients under 70. If the patient was over 70, had symptoms from his aneurysm and had 3 or more 'risk factors' (cardiac disease, hypertension, chronic obstructive airways disease, peripheral vascular disease, cerebro-vascular disease, diabetes, chronic renal failure, previous pulmonary embolism) the mortality rose to 44()0. Esselstyne (13) comparing the mortality in elective on patients over or under the age of 75 found that olperation thie operative mortality was not related to age, but was related to whether or not the patietnt had symptoms from his aneurvsm (490) vs 12 Man\y authors have reported that the risk of rupture is related to size (2, 6, 14). Clinical estimation of the size of an aneurysm by palpation has been shows\n to correlate poorly with measurement by ultrasound or at operation; whereas ultrasound and measurement at operaton have been found to correlate w%-ell (15). Shumacker (16), and WValker (17) have described dense peri-anieurvsmal fibrosis. The aneurysmns have a thick firm smooth w all which is shiny white in appearance. The histology showed dense inflammatory tissue. The incidence of rupture was 15"O (3/19) compared with 400O (65/168) in arteriosclerotic aneurysms. Darke (18) reviewed 27 patients with ureteric obstruction and aortic aneurysm. Advocating aneurysmectomy and ureterolysis this group of workers reported that the ESR fell to normal postoperatively, suggesting that the aneurysm was the primary pathology. Grafting of these inflammatory aneurysms may, however, be technically difficult as was the case in two patients presented hiere. Conclusions Approximately half the patients who presented with an abdominal aortic aneurysm in a 10 year period did not present uiitil the aneurysm had ruptured. Thle diagnosis of ruptured abdominal aortic aneurysm will be missed unless it is specifically considered, and should be thoughlt of in all elderly patients presenting with abdominal pain and circulatory collapse, or in whom no other positive diagnosis can be made. 313 If there is doubt about the diagnosis of ruptured abdominal aortic aneurysm time is available for simple investigations such as plain abdominal radiographs before irreversible deterioration takes place. The mortality from rupture in patients known to have an abdominal aortic aneurysm is so high that conservative management is unacceptable in all but the very poor risk patient. References I Darling RC, NMessina R, Brewster DC, Ottinger LWV. Autopsy study of unoperated abdominal aortic aneurysms. Circulation 1977;56: suppl 161-4. 2 Darling, RC. 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