Br. J. Surg. Vol. 63 (1976) 113-116
Unoperated ruptured abdominal aortic aneurysms : a retrospective clinicopathological study over a 10-year period J O H N C. M c G R E G O R * SUMMARY
A series is described of 41 cases of unoperated ruptured abdominal aortic aneurysm in 9894 consecutive autopsies performed in two large general hospitals in Glasgow between I964 and 1974. The preceding clinicatpresentations are discussed. These show the dificulties in diagnosing the condition correctly and quickly and the liability to confusion with other intra-abdominal conditions. The correct diagnosis was established before death in only 11 cases, it was suspected in 6 cases and was completely missed in 24 cases. Pathologically, all the cases were atheromatous and measured more than 5 cm in diameter, and the most common site of rupture was through the lateral wall, Resection would appear to have been technically possible without undue dificulties in the majority of the cases. An analysis of all the findings indicates the necessity for greater clinical awareness of this condition and its variable mode of presentation. Only in this way will early diagnoJis and safer siirgical intervention be possible.
OSLER(1905) drew attention to some difficulties in correctly diagnosing the presence of an abdominal aortic aneurysm. These difficulties remain even today; indeed, abdominal aortic aneurysms have been confused with almost every intra-abdominal and retroperitoneal syndrome known (Eliason and McNamee, 1942). This unfortunately is just as true when an abdominal aortic aneurysm ruptures (Pryor, 1972). The mortality in untreated cases is 100 per cent; even when operation is performed half the patients may die (Alpert et al., 1970). Greater emphasis needs to be placed on immediate diagnosis and earlier treatment in order to save life. Pryor’s (1972) retrospective clinical analysis of 44 cases of ruptured abdominal aortic aneurysm demonstrated how difficult this can be. In only 14 of his cases was the correct diagnosis made at the time of admission, while in 15 patients it was unsuspected until necropsy. No analysis of the reasons for misdiagnosis was made apart from the lack of awareness of thc variable clinical presentation and the importance of careful abdominal examination. Two large studies have been made of non-resected ruptured abdominal aortic aneurysms (Crane, 1955; Darling, 1970). Both attempted to combine clinical and pathological observations. Although these authors included and discussed the preceding clinical presentations, neither mentioned diagnostic confusion or emphasized the need for greater clinical awareness in arriving at the correct diagnosis.
It was with this in mind that the present clinicopathological retrospective study was undertaken. A total of 41 cases who were found at autopsy to have died as a result of a ruptured abdominal aortic aneurysm were studied. The pathology records from 1964 to 1974 inclusive for Stobhill General Hospital and the Royal Infirmary, Glasgow, were used to trace the patients initially. An analysis was then made of the clinical and pathological observations in order to try to demonstrate the variable nature of the condition and to clarify the reasons for misdiagnosis.
Results From 1964 to 1974 inclusive a total of 9894 consecutive autopsies were studied restrospectively, and details extracted from the official post-mortem records were matched with those obtained from the clinical case records. Clinical details of 5 cases could not be traced but pathology records were available for all the cases. Altogether 41 cases of unoperated ruptured abdominal aortic aneurysm were found; 26 were male. The average age of the patients was 74.5 years (range 60-89 years). Clinical details Thirty-five of the cases were referred to hospital as emergencies but 5 had already been admitted for other reasons not apparently directly related to the abdominal aortic aneurysm which subsequently ruptured (Table I ) . I n I case the reason for admission to hospital was unrecorded. The duration of the preceding history ranged from 2 hours to 2 months, but in most instances it was short (24 hours or less). The time interval between admission and death varied from 30 minutes to 26 months (in a patient admitted to a geriatric ward for social reasons), with the majority dying within 48 hours. The correct diagnosis of a ruptured abdominal aortic aneurysm was made before death in only 1 1 cases, though it was suspected in another 6. The diagnosis was completely missed in 24 cases. Table I I lists the diagnoses made. Only 4 out of the 41 patients were known to have an abdominal aortic aneurysm before admission. Twenty-one patients were noted to have an abdominal mass which was pulsatile in 18. The mass occurred most frequently in the mid- or left upper abdomen (Table ZIZ). The main symptom recorded in 30 out of the 41 cases was abdominal pain, generally of sudden onset
* Stobhill General Hospital, Glasgow. 113
John C. McCregor Table I : DETAILS OF 5 CASES WHO WERE ADMITTED TO HOSPITAL FOR REASONS NOT DIRECTLY RELATED TO THE ANEURYSM Time between admission and death Mass in abdomen Reason A ae Sex Ward 71 78 77 72 80
M M F M F
Geriatric Surgical Gynaecology Geriatric Geriatric
Table 11: DIAGNOSES MADE Intestinal obstruction Pancreatitis Ureteric colic Diverticulitis I ntra-abdominal haemorrhage Ischaemic colitis Retention of urine Gastric neoplasm Bacteraemic shock Myocardial infarction Left ventricular failure Cerebrovascular disorder Unknown
Social/cardiovascular accident Cancer of rectum Procidentia Social/cardiovascular accident Social
No. of cases: 4 2 2 1
1 5 1
1 3
Table 111: POSITION OF MASS IN ABDOMEN Upper abdomen No. of cases: 2 Right 7 Left L Centre Lower abdomen 0 Right 1 Left 1 Centre J Mid-abdomen 3 Not given Table 1V: SIGNS AND SYMPTOMS IN PATIENTS WITH CONFIRMED OR SUSPECTED ANEURYSM COMPARED WITH THOSE IN WHOM THE DIAGNOSIS WAS MISSED Diagnosis Diagnosis definite or possible missed ( n = 17) ( I ? = 23) Signs and symptoms 5 16 Abdominal mass 9 8 Backache 10 10 Hypotension 7 L Abdominal distension 1 1 External bruising 2 10 Obesity 16 11 Abdominal pain 4 4 Gastro-intestinal haemorrhage 2 4 Urological 0 0 Neuroloeical
and severe constant character. In 7 backache was the main symptom. Only 9 patients presented with the classic triad of shock, abdominal pain and a pulsatile abdominal mass. Table ZV records some of the signs and symptoms that were noted and the findings for the group Of patients with confirmed or susDected aneurysm with those in whom the diagnosis was completely missed. Abdominal tenderness and even guarding were observed in many Of the patients; in none were sounds reported to be absent*The recording Of lower limb reflexes and femoral pulses had been omitted 114
None noted None noted ? Aneurysm None noted Aneurysm noted
2 mth 6d 7d 21 d 26 mth
from most of the records; no conclusions could be reached from the remainder. Eight patients had vomiting of either altered blood or fresh blood (2 cases). A plain X-ray of the abdomen had been performed in most of the patients on admission but only 7 appeared to have had a lateral X-ray specifically looking for calcification in an abdominal aortic aneurysm. Calcification was present in 6 cases of which 4 indicated that an aneurysm was present. Only 1 patient had had an aortogram performed. This had shown an abdominal aortic aneurysm 1 year before emergency admission to hospital with rupture. Reasons for no operation when n correct diagnosis was made The diagnosis was correctly and rapidly made soon after admission in 11 cases. In 6 of these it was decided by senior surgeons that n o operative intervention should be undertaken because of the patient’s ‘general poor condition-and age’. Two patients died while arrangements were being made for surgery, 1 died in the casualty department before admission, having arrived in a moribund state, and in the remaining 2 no reason for lack of operative intervention was given. In 3 of this group of 11 cases abdominal aortic aneurysm had been known to be present for 2, 3 and 8 years before rupture respectively, but apparently elective surgery had never been considered. Reasons for suspected but uncertain diagnosis In 6 cases the diagnosis of a ruptured abdominal aortic aneurysm was considered to be a possibility but was not certain. Case 1 : A 68-year-old man presented with pain suggestive of right ureteric colic. Clinically, an abdominal aneurysm was noted but was assumed to be intact initially. However, after a few hours the patient became hypotensive and died within 12 hours of admission.
Case 2: A 76-year-old woman was admitted, following a domicilary visit, with a n epigastric mass, abdominal pain, vomiting and a history of pernicious anaemia. The initial diagnosis had been a gastric carcinoma, but she was seen subsequently a few days after admission by a vascular surgeon who thought that an aneurysm was likely. Preparations were being made to treat her anaemia prior to surgery, but she became hypotensive and died 15 days after her admission. Case 3: An 83-year-old man was admittedmoribundand unable to give a precise history. The absence of pain together with a slow pulse rate in the presence of shock were considered to preclude a diagnosis of leaking abdominal aortic aneurysm. (A pulsatile abdominal mass was noted.) The patient died within 24 hours of admission.
case4, 86-year-old was admitted with an 8-hour history of lower left-sided abdominal pain. An aortic aneurysm was noted and assumed to be intact because the patient
Unoperated ruptured abdominal aortic aneurysms appeared normotensive. The patient died within 48 hours of admission following a hypotensive episode. Case 5 : An 80-year-old woman was admitted to a geriatric ward for social reasons. She was noted to have an upper abdominal pulsatile mass thought to be either an aortic aneurysm or a carcinoma of the pancreas. Just over 2 years later she developed abdominal pain and died suddenly without surgical intervention or a final diagnosis being made. Case 6 : A 73-year-old man was admitted as an emergency, having collapsed the same day. A pulsatile mass was noted in the abdomen. Because he was normotensive and did not complain of pain it was incorrectly assumed that the aneurysm was intact. The patient died within 12 hours.
Pathological observations All 41 abdominal aortic aneurysms were associated with atherosclerosis. No case of syphilitic disease was present in this series. Eleven fusiform and 11 saccular aneurysms were noted. Associated aneurysms were recorded in 3 patients; these were of the right femoral, thoracic aorta and both common iliac arteries respectively. The average transverse diameter of the aortic aneurysms recorded in 13 cases was 9.4 cm (range 5-15 cm); in the others miscellaneous descriptive terms inferred a general tendency towards large size. In 26 patients the aneurysm was infrarenal, in 2 it extended above the renal arteries, in 1 it extended to the level of the renal arteries and in 12 the position was not recorded. Rupture occurred extraperitoneally in 1 case, but in the rest it was into the peritoneum. Rupture into important neighbouring structures occurred in 5 cases. These were: inferior vena cava (I), left perinephric tissues ( 2 ) and posterior wall of the third part of the duodenum ( 2 ) . The site of the rupture of the aneurysm wall varied although it appeared to occur most commonly through the lateral walls (Table V). In 5 cases the size of the rupture externally was recorded and ranged from I to 4cm. Thick laminated thrombus was noted in many of the aneurysms, but no measurements of the wall thickness were made which would have enabled correlation with the site of rupture. Discussion Although there must always be some deficiencies in the interpretation of retrospective information it is clear that this study provides some interesting and valid conclusions. There is no doubt that while atherosclerotic abdominal aortic aneurysms have become more common since the report of Osler (1905), there is still difficulty and uncertainty in diagnosing the condition. When an aneurysm ruptures the result will be death unless operative intervention is undertaken quickly. In the present series the time between the onset of symptoms due to rupture and death was less than 24 hours in the majority of cases. The true incidence of ruptured aneurysm is unknown since many patients probably die undiagnosed outside hospital. Only in 1 case referred to hospital as an emergency by a general practitioner was the diagnosis of possible ruptured abdominal aortic aneurysm made before admission. There is, therefore, a real need for early
Table V: SITE OF RUPTURE Anterior Posterior Left lateral Right lateral Left anterolateral Right anterolateral Left posterolateral Right posterolateral Unrecorded
No. of cases: 5 4 11 5 1
3 5
0 I
identification of the condition. The diagnosis would not be unduly difficult provided that the clinician is aware of the various clinical presentations and looks specifically for an abdominal mass in all patients. In this series these points d o not appear to have been considered often enough. To some extent this may be because usually relatively junior staff initially examined the patients on admission, but more senior staff are not blameless in this. However, when clinicians with experience in vascular surgery saw the patient the diagnosis was usually made quickly. Misinterpretation of the clinical observations showed itself in a number of ways : 1. An abdominal mass which should have been noted was not observed. (Most of the ruptured aneurysms were large.) 2. An abdominal mass which might have otherwise been noted was obscured by abdominal distension or obesity (Table ZV). 3. An abdominal mass was observed but its significance was missed because of position, lack of pulsation or confusion with other possible causes (e.g. faeces, pancreatic or gastric lesions). 4. An observed abdominal aortic aneurysm was considered to be intact. 5. The mistaken assumption that ruptured aneurysms are always associated with the classic triad of a pulsatile mass, hypotension and abdominal pain. 6 . Other mistaken assumptions that a ruptured aneurysm is unlikely when the patient has no pain, is not apparently hypotensive or has no palpable mass. These clinical observations may be made because the patient cannot give a coherent history, may normally be hypertensive or may have an impalpable mass for reasons given above (2). 7. The lack of investigative procedures directed at identifying aortic aneurysms (e.g. lateral X-rays). The pathological findings confirm that atheroma is the usual cause of abdominal aortic aneurysm today. In agreement with other authors (Crane, 1955; Darling, 1970) it seems that aneurysms which rupture are likely to be large (i.e. 7 cm or more in diameter). This, together with the fact that smaller abdominal aortic aneurysms tend to occur in a younger population and appear less likely to rupture, suggests that progression from small to large occurs with time and is associated with an increasing risk of rupture. At present, since little is known about the natural development of aneurysms and their rate of growth, there is an obvious need to look for and identify the presence of an aneurysm at an early stage. Operating before rupture of the aneurysm carries a reasonable 115
John C. McGregor prognosis (DeBakey et al., 1964). When a ruptured aneurysm is diagnosed early the chances of survival after operation are good enough to justify surgical intervention in most cases (Alpert et al., 1970). Even in the presence of profound shock early operation may be successful (Shumacker et al., 1973). In the present series 4 patients were known to have abdominal aortic aneurysms long before their admission for rupture; possibly elective surgery at a n earlier stage should have been considered. It is of interest that since the majority of the aneurysms occurred below the level of the renal arteries, surgery would have been technically feasible relatively early in almost all the cases. This observation was also made by Crane (1955) and Darling (1970) in their series. As an aid to diagnosis in difficult cases, apart from improved clinical awareness, ordinary radiological studies should be used. Where available, ultrasonography offers a more precise and rapid non-invasive technique that can be employed as a screening procedure in the diagnosis of intact aortic aneurysms (McGregor et al., 1975a). It may also be of value in demonstrating rupture (McGregor et al., 1975b). Acknowledgements I would like to thank the Pathology Departments of Stobhill Hospital and the Royal Infirmary, Glasgow, for allowing access to their records. My thanks are also due to the Medical Records Officers of these hospitals for making available the case records and to Mrs C. M. Nasmyth and her staff for typing the manuscript.
116
References and PARSONNET v. (1970) Surgery for the ruptured aortic aneurysm. JAMA 212, 1355-1 359. CRANE c. (1955) Arteriosclerotic aneurysm of the abdominal aorta. Some pathological and clinical correlations. New Engl. J . Med. 253, 954-958. DARLING R. c. (1970) Ruptured arteriosclerotic abdominal aortic aneurysms. A pathological and clinical study. Am. J. Surg. 119, 397401. ALPERT J., BRIEF D. K.
DEBAKEY M. E., CRAWFORD E. S., COOLEY D. A., MORRIS G. c., ROYSTER T. s. and ABBOTT w. P. (1964)
Aneurysm of abdominal aorta. Ann. Surg. 160, 622-639. ELIASON E. L. and MCNAMEE H. G. (1942) Abdominal aneurysm. Report on 24 cases. Am. J . Surg. 56, 590-593. MCGREGOR J. c., POLLOCK J . G. and ANTON H. c. (1975a) The value of ultrasonography in the diagnosis of abdominal aortic aneurysm. Scott. Med. J . 20, 133-137. MCGREGOR J. c., POLLOCK J . C. and ANTON H. c. ( I 975b) Ultrasonography in the investigation of possible ruptured abdominal aortic aneurysm. Br. Med. J . 3, 78-79. OSLER w. (1905) Aneurysm of the abdominal aorta. Lancet 2, 1089-1 096. PRYOR J. P. (1972) Diagnosis of ruptured aneurysm of abdominal aorta. Br. Med. J . 3, 735-736. SHUMACKER H. B., BARNES D. L. and KING H. (1973) Ruptured abdominal aortic aneurysms. Ann. Surg. 177, 772-779.
Unoperated ruptured abdominal aortic aneurysms : a retrospective clinicopathological study over a 10-year period J O H N C. M c G R E G O R * SUMMARY
A series is described of 41 cases of unoperated ruptured abdominal aortic aneurysm in 9894 consecutive autopsies performed in two large general hospitals in Glasgow between I964 and 1974. The preceding clinicatpresentations are discussed. These show the dificulties in diagnosing the condition correctly and quickly and the liability to confusion with other intra-abdominal conditions. The correct diagnosis was established before death in only 11 cases, it was suspected in 6 cases and was completely missed in 24 cases. Pathologically, all the cases were atheromatous and measured more than 5 cm in diameter, and the most common site of rupture was through the lateral wall, Resection would appear to have been technically possible without undue dificulties in the majority of the cases. An analysis of all the findings indicates the necessity for greater clinical awareness of this condition and its variable mode of presentation. Only in this way will early diagnoJis and safer siirgical intervention be possible.
OSLER(1905) drew attention to some difficulties in correctly diagnosing the presence of an abdominal aortic aneurysm. These difficulties remain even today; indeed, abdominal aortic aneurysms have been confused with almost every intra-abdominal and retroperitoneal syndrome known (Eliason and McNamee, 1942). This unfortunately is just as true when an abdominal aortic aneurysm ruptures (Pryor, 1972). The mortality in untreated cases is 100 per cent; even when operation is performed half the patients may die (Alpert et al., 1970). Greater emphasis needs to be placed on immediate diagnosis and earlier treatment in order to save life. Pryor’s (1972) retrospective clinical analysis of 44 cases of ruptured abdominal aortic aneurysm demonstrated how difficult this can be. In only 14 of his cases was the correct diagnosis made at the time of admission, while in 15 patients it was unsuspected until necropsy. No analysis of the reasons for misdiagnosis was made apart from the lack of awareness of thc variable clinical presentation and the importance of careful abdominal examination. Two large studies have been made of non-resected ruptured abdominal aortic aneurysms (Crane, 1955; Darling, 1970). Both attempted to combine clinical and pathological observations. Although these authors included and discussed the preceding clinical presentations, neither mentioned diagnostic confusion or emphasized the need for greater clinical awareness in arriving at the correct diagnosis.
It was with this in mind that the present clinicopathological retrospective study was undertaken. A total of 41 cases who were found at autopsy to have died as a result of a ruptured abdominal aortic aneurysm were studied. The pathology records from 1964 to 1974 inclusive for Stobhill General Hospital and the Royal Infirmary, Glasgow, were used to trace the patients initially. An analysis was then made of the clinical and pathological observations in order to try to demonstrate the variable nature of the condition and to clarify the reasons for misdiagnosis.
Results From 1964 to 1974 inclusive a total of 9894 consecutive autopsies were studied restrospectively, and details extracted from the official post-mortem records were matched with those obtained from the clinical case records. Clinical details of 5 cases could not be traced but pathology records were available for all the cases. Altogether 41 cases of unoperated ruptured abdominal aortic aneurysm were found; 26 were male. The average age of the patients was 74.5 years (range 60-89 years). Clinical details Thirty-five of the cases were referred to hospital as emergencies but 5 had already been admitted for other reasons not apparently directly related to the abdominal aortic aneurysm which subsequently ruptured (Table I ) . I n I case the reason for admission to hospital was unrecorded. The duration of the preceding history ranged from 2 hours to 2 months, but in most instances it was short (24 hours or less). The time interval between admission and death varied from 30 minutes to 26 months (in a patient admitted to a geriatric ward for social reasons), with the majority dying within 48 hours. The correct diagnosis of a ruptured abdominal aortic aneurysm was made before death in only 1 1 cases, though it was suspected in another 6. The diagnosis was completely missed in 24 cases. Table I I lists the diagnoses made. Only 4 out of the 41 patients were known to have an abdominal aortic aneurysm before admission. Twenty-one patients were noted to have an abdominal mass which was pulsatile in 18. The mass occurred most frequently in the mid- or left upper abdomen (Table ZIZ). The main symptom recorded in 30 out of the 41 cases was abdominal pain, generally of sudden onset
* Stobhill General Hospital, Glasgow. 113
John C. McCregor Table I : DETAILS OF 5 CASES WHO WERE ADMITTED TO HOSPITAL FOR REASONS NOT DIRECTLY RELATED TO THE ANEURYSM Time between admission and death Mass in abdomen Reason A ae Sex Ward 71 78 77 72 80
M M F M F
Geriatric Surgical Gynaecology Geriatric Geriatric
Table 11: DIAGNOSES MADE Intestinal obstruction Pancreatitis Ureteric colic Diverticulitis I ntra-abdominal haemorrhage Ischaemic colitis Retention of urine Gastric neoplasm Bacteraemic shock Myocardial infarction Left ventricular failure Cerebrovascular disorder Unknown
Social/cardiovascular accident Cancer of rectum Procidentia Social/cardiovascular accident Social
No. of cases: 4 2 2 1
1 5 1
1 3
Table 111: POSITION OF MASS IN ABDOMEN Upper abdomen No. of cases: 2 Right 7 Left L Centre Lower abdomen 0 Right 1 Left 1 Centre J Mid-abdomen 3 Not given Table 1V: SIGNS AND SYMPTOMS IN PATIENTS WITH CONFIRMED OR SUSPECTED ANEURYSM COMPARED WITH THOSE IN WHOM THE DIAGNOSIS WAS MISSED Diagnosis Diagnosis definite or possible missed ( n = 17) ( I ? = 23) Signs and symptoms 5 16 Abdominal mass 9 8 Backache 10 10 Hypotension 7 L Abdominal distension 1 1 External bruising 2 10 Obesity 16 11 Abdominal pain 4 4 Gastro-intestinal haemorrhage 2 4 Urological 0 0 Neuroloeical
and severe constant character. In 7 backache was the main symptom. Only 9 patients presented with the classic triad of shock, abdominal pain and a pulsatile abdominal mass. Table ZV records some of the signs and symptoms that were noted and the findings for the group Of patients with confirmed or susDected aneurysm with those in whom the diagnosis was completely missed. Abdominal tenderness and even guarding were observed in many Of the patients; in none were sounds reported to be absent*The recording Of lower limb reflexes and femoral pulses had been omitted 114
None noted None noted ? Aneurysm None noted Aneurysm noted
2 mth 6d 7d 21 d 26 mth
from most of the records; no conclusions could be reached from the remainder. Eight patients had vomiting of either altered blood or fresh blood (2 cases). A plain X-ray of the abdomen had been performed in most of the patients on admission but only 7 appeared to have had a lateral X-ray specifically looking for calcification in an abdominal aortic aneurysm. Calcification was present in 6 cases of which 4 indicated that an aneurysm was present. Only 1 patient had had an aortogram performed. This had shown an abdominal aortic aneurysm 1 year before emergency admission to hospital with rupture. Reasons for no operation when n correct diagnosis was made The diagnosis was correctly and rapidly made soon after admission in 11 cases. In 6 of these it was decided by senior surgeons that n o operative intervention should be undertaken because of the patient’s ‘general poor condition-and age’. Two patients died while arrangements were being made for surgery, 1 died in the casualty department before admission, having arrived in a moribund state, and in the remaining 2 no reason for lack of operative intervention was given. In 3 of this group of 11 cases abdominal aortic aneurysm had been known to be present for 2, 3 and 8 years before rupture respectively, but apparently elective surgery had never been considered. Reasons for suspected but uncertain diagnosis In 6 cases the diagnosis of a ruptured abdominal aortic aneurysm was considered to be a possibility but was not certain. Case 1 : A 68-year-old man presented with pain suggestive of right ureteric colic. Clinically, an abdominal aneurysm was noted but was assumed to be intact initially. However, after a few hours the patient became hypotensive and died within 12 hours of admission.
Case 2: A 76-year-old woman was admitted, following a domicilary visit, with a n epigastric mass, abdominal pain, vomiting and a history of pernicious anaemia. The initial diagnosis had been a gastric carcinoma, but she was seen subsequently a few days after admission by a vascular surgeon who thought that an aneurysm was likely. Preparations were being made to treat her anaemia prior to surgery, but she became hypotensive and died 15 days after her admission. Case 3: An 83-year-old man was admittedmoribundand unable to give a precise history. The absence of pain together with a slow pulse rate in the presence of shock were considered to preclude a diagnosis of leaking abdominal aortic aneurysm. (A pulsatile abdominal mass was noted.) The patient died within 24 hours of admission.
case4, 86-year-old was admitted with an 8-hour history of lower left-sided abdominal pain. An aortic aneurysm was noted and assumed to be intact because the patient
Unoperated ruptured abdominal aortic aneurysms appeared normotensive. The patient died within 48 hours of admission following a hypotensive episode. Case 5 : An 80-year-old woman was admitted to a geriatric ward for social reasons. She was noted to have an upper abdominal pulsatile mass thought to be either an aortic aneurysm or a carcinoma of the pancreas. Just over 2 years later she developed abdominal pain and died suddenly without surgical intervention or a final diagnosis being made. Case 6 : A 73-year-old man was admitted as an emergency, having collapsed the same day. A pulsatile mass was noted in the abdomen. Because he was normotensive and did not complain of pain it was incorrectly assumed that the aneurysm was intact. The patient died within 12 hours.
Pathological observations All 41 abdominal aortic aneurysms were associated with atherosclerosis. No case of syphilitic disease was present in this series. Eleven fusiform and 11 saccular aneurysms were noted. Associated aneurysms were recorded in 3 patients; these were of the right femoral, thoracic aorta and both common iliac arteries respectively. The average transverse diameter of the aortic aneurysms recorded in 13 cases was 9.4 cm (range 5-15 cm); in the others miscellaneous descriptive terms inferred a general tendency towards large size. In 26 patients the aneurysm was infrarenal, in 2 it extended above the renal arteries, in 1 it extended to the level of the renal arteries and in 12 the position was not recorded. Rupture occurred extraperitoneally in 1 case, but in the rest it was into the peritoneum. Rupture into important neighbouring structures occurred in 5 cases. These were: inferior vena cava (I), left perinephric tissues ( 2 ) and posterior wall of the third part of the duodenum ( 2 ) . The site of the rupture of the aneurysm wall varied although it appeared to occur most commonly through the lateral walls (Table V). In 5 cases the size of the rupture externally was recorded and ranged from I to 4cm. Thick laminated thrombus was noted in many of the aneurysms, but no measurements of the wall thickness were made which would have enabled correlation with the site of rupture. Discussion Although there must always be some deficiencies in the interpretation of retrospective information it is clear that this study provides some interesting and valid conclusions. There is no doubt that while atherosclerotic abdominal aortic aneurysms have become more common since the report of Osler (1905), there is still difficulty and uncertainty in diagnosing the condition. When an aneurysm ruptures the result will be death unless operative intervention is undertaken quickly. In the present series the time between the onset of symptoms due to rupture and death was less than 24 hours in the majority of cases. The true incidence of ruptured aneurysm is unknown since many patients probably die undiagnosed outside hospital. Only in 1 case referred to hospital as an emergency by a general practitioner was the diagnosis of possible ruptured abdominal aortic aneurysm made before admission. There is, therefore, a real need for early
Table V: SITE OF RUPTURE Anterior Posterior Left lateral Right lateral Left anterolateral Right anterolateral Left posterolateral Right posterolateral Unrecorded
No. of cases: 5 4 11 5 1
3 5
0 I
identification of the condition. The diagnosis would not be unduly difficult provided that the clinician is aware of the various clinical presentations and looks specifically for an abdominal mass in all patients. In this series these points d o not appear to have been considered often enough. To some extent this may be because usually relatively junior staff initially examined the patients on admission, but more senior staff are not blameless in this. However, when clinicians with experience in vascular surgery saw the patient the diagnosis was usually made quickly. Misinterpretation of the clinical observations showed itself in a number of ways : 1. An abdominal mass which should have been noted was not observed. (Most of the ruptured aneurysms were large.) 2. An abdominal mass which might have otherwise been noted was obscured by abdominal distension or obesity (Table ZV). 3. An abdominal mass was observed but its significance was missed because of position, lack of pulsation or confusion with other possible causes (e.g. faeces, pancreatic or gastric lesions). 4. An observed abdominal aortic aneurysm was considered to be intact. 5. The mistaken assumption that ruptured aneurysms are always associated with the classic triad of a pulsatile mass, hypotension and abdominal pain. 6 . Other mistaken assumptions that a ruptured aneurysm is unlikely when the patient has no pain, is not apparently hypotensive or has no palpable mass. These clinical observations may be made because the patient cannot give a coherent history, may normally be hypertensive or may have an impalpable mass for reasons given above (2). 7. The lack of investigative procedures directed at identifying aortic aneurysms (e.g. lateral X-rays). The pathological findings confirm that atheroma is the usual cause of abdominal aortic aneurysm today. In agreement with other authors (Crane, 1955; Darling, 1970) it seems that aneurysms which rupture are likely to be large (i.e. 7 cm or more in diameter). This, together with the fact that smaller abdominal aortic aneurysms tend to occur in a younger population and appear less likely to rupture, suggests that progression from small to large occurs with time and is associated with an increasing risk of rupture. At present, since little is known about the natural development of aneurysms and their rate of growth, there is an obvious need to look for and identify the presence of an aneurysm at an early stage. Operating before rupture of the aneurysm carries a reasonable 115
John C. McGregor prognosis (DeBakey et al., 1964). When a ruptured aneurysm is diagnosed early the chances of survival after operation are good enough to justify surgical intervention in most cases (Alpert et al., 1970). Even in the presence of profound shock early operation may be successful (Shumacker et al., 1973). In the present series 4 patients were known to have abdominal aortic aneurysms long before their admission for rupture; possibly elective surgery at a n earlier stage should have been considered. It is of interest that since the majority of the aneurysms occurred below the level of the renal arteries, surgery would have been technically feasible relatively early in almost all the cases. This observation was also made by Crane (1955) and Darling (1970) in their series. As an aid to diagnosis in difficult cases, apart from improved clinical awareness, ordinary radiological studies should be used. Where available, ultrasonography offers a more precise and rapid non-invasive technique that can be employed as a screening procedure in the diagnosis of intact aortic aneurysms (McGregor et al., 1975a). It may also be of value in demonstrating rupture (McGregor et al., 1975b). Acknowledgements I would like to thank the Pathology Departments of Stobhill Hospital and the Royal Infirmary, Glasgow, for allowing access to their records. My thanks are also due to the Medical Records Officers of these hospitals for making available the case records and to Mrs C. M. Nasmyth and her staff for typing the manuscript.
116
References and PARSONNET v. (1970) Surgery for the ruptured aortic aneurysm. JAMA 212, 1355-1 359. CRANE c. (1955) Arteriosclerotic aneurysm of the abdominal aorta. Some pathological and clinical correlations. New Engl. J . Med. 253, 954-958. DARLING R. c. (1970) Ruptured arteriosclerotic abdominal aortic aneurysms. A pathological and clinical study. Am. J. Surg. 119, 397401. ALPERT J., BRIEF D. K.
DEBAKEY M. E., CRAWFORD E. S., COOLEY D. A., MORRIS G. c., ROYSTER T. s. and ABBOTT w. P. (1964)
Aneurysm of abdominal aorta. Ann. Surg. 160, 622-639. ELIASON E. L. and MCNAMEE H. G. (1942) Abdominal aneurysm. Report on 24 cases. Am. J . Surg. 56, 590-593. MCGREGOR J. c., POLLOCK J . G. and ANTON H. c. (1975a) The value of ultrasonography in the diagnosis of abdominal aortic aneurysm. Scott. Med. J . 20, 133-137. MCGREGOR J. c., POLLOCK J . C. and ANTON H. c. ( I 975b) Ultrasonography in the investigation of possible ruptured abdominal aortic aneurysm. Br. Med. J . 3, 78-79. OSLER w. (1905) Aneurysm of the abdominal aorta. Lancet 2, 1089-1 096. PRYOR J. P. (1972) Diagnosis of ruptured aneurysm of abdominal aorta. Br. Med. J . 3, 735-736. SHUMACKER H. B., BARNES D. L. and KING H. (1973) Ruptured abdominal aortic aneurysms. Ann. Surg. 177, 772-779.
