Optimal interval screening and surveillance of abdominal aortic aneurysms.

OBJECTIVES: to determine safe and optimal intervals of rescreening and surveillance for AAA. METHODS: hospital-based mass screening of 6339 65-73-year-old men from 1994-98. 76.4% attended. One hundred and ninety-one (4%) had AAA53 cm. Twenty-four (0.5%) were initially >5 cm and referred for surgery, while the rest were offered annual control scans to check for expansion. Later, all 348 (7.5%) men who 3 to 5 years ago had an ectatic aorta (infrarenal aortic diameter of 25-29 mm or distal/renal aortic diameter ratio >1.2) were offered rescreening. Of these, 62 (18%) died before rescanning, while 248 of the survivors attended rescreening (87%). Furthermore, a random sample of 380 of those with non-ectatic aortas were offered rescreening. Of these, 49 (13%) died before rescreening (p=0.06), while 275 (83%) of the survivors attended re-screening. RESULTS: none of the controls had developed AAA. Of those who initially had an 25-29 mm aorta, 29% had developed AAA (size range 30-48 mm) with expansion rates varying from 1.0 to 4.7 mm/year. Only 3.5% with a ratio >1.2 developed AAA (size range: 30-34 mm) with expansion rates from 1.3 to 2.4 mm/year. During the fourth year of surveillance some AAA initially sized below 3.5 cm expanded to above 5 cm, while some sized 3.5-3.9 cm did so during the second year, >4 cm did so during the first year of surveillance. CONCLUSION: rescreening for AAA can be restricted to initially ectatic aortas sized 25-29 mm at 5-year intervals. Surveillance of small AAA can be restricted to 1-4 year intervals.     

Inflammatory abdominal aortic aneurysms.

BACKGROUND: Inflammatory abdominal aortic aneurysms (IAAA) are a variant of aortic aneurysm characterised by extensive peri-aneurysmal fibrosis, thickened walls and dense adhesions and represent between 3 and 10% of all abdominal aortic aneurysms (AAA). Surgery is technically challenging and is still associated with an increased morbidity and mortality. Controversy exists about aetiology and pathogenesis. METHODS: We review the literature on the current theories, the available imaging modalities and the current thinking on management of IAAA. A Medline database search was performed. Articles were cross-referenced. RESULTS AND CONCLUSIONS: Aneurysm development is multifactorial with important genetic and environmental factors. The literature supports the theory that IAAA arise from the same antigenic stimulus that is responsible for the non-IAAA, representing one extreme of an inflammatory spectrum. The results after open repair have improved and there is now little difference in the mortality between non-IAAA and IAAA repair. However, there is likely to be a role for endovascular stenting in IAAA management and this requires further study. It is clear that closer follow-up of patients after IAAA repair with either technique is necessary to monitor the inflammatory process. No evidence-based follow-up protocol exists but three to six-monthly monitoring of renal function and erythrocyte sedimentation rate (ESR) for 24 months post-repair would seem a reasonable regime.     

Elective surgery for small abdominal aortic aneurysms.

BACKGROUND AND PURPOSE: Surgical repair for abdominal aortic aneurysm has become more frequent and the mortality associated with elective surgery has been reduced, but the overall mortality for ruptured aneurysm remains unacceptably high. The dilemma for the vascular surgeon is whether to operate early and electively on asymptomatic small aneurysms, less than 5 cm in diameter, or to delay surgery, adopting a wait-and-see attitude. The purpose of this retrospective study was to review a recent 5-year experience of elective aneurysm surgery, with special emphasis on the perioperative outcome of surgical repair of asymptomatic small aneurysms, in order to evaluate whether early mortality and morbidity justify an aggressive approach. METHODS: The report concerns a series of 141 consecutive patients who underwent aneurysm repair for small (n = 65, group I) and large aneurysms (n = 76, group II). For each group, the age, sex, risk factors and associated diseases, operative and aortic cross-clamping times, estimated blood loss, blood transfusion volume, type of operation and graft, perioperative morbidity and mortality, and causes of death were recorded and compared. RESULTS: The majority of patients were males. The mean age of the patients was lower in group I than in group II. No statistically significant difference was found from the comparison of the risk factors and associated diseases in groups I and II. The mean operating time was 82 minutes in group I, 98 minutes in group II, and the aortic cross-clamping time was also shorter in group I (37 min versus 52 min), whereas blood loss was greater, with a statistically significant difference (P < 0.05). The operative mortality rate was higher in group II than in group I (1.3% versus 0%, P = NS). CONCLUSIONS: Elective small aneurysm repair is recommended in good-risk patients for the following reasons: (i) the operative mortality and morbidity rates are lower in small than in large aneurysm patients, and (ii) the small aneurysm repair is technically easier and safer to perform. In addition, there are two other considerations that are more difficult to quantify, but may support an aggressive approach: the cost-benefit ratio is better with early diagnosis and elective surgery, before an emergency operation is required, and personal choice and psychological reasons can induce patients to prefer early elective repair to periodic monitoring by ultrasound or computed tomography scans.     

Endovascular treatment of abdominal aortic aneurysms.

OBJECTIVE: The purpose of this paper is to briefly review the historical aspects and outcome of endoluminal abdominal aortic aneurysm (AAA) repair and summarise two studies presented at the 1997 and 1998 meetings of the Society for Vascular Surgery. PATIENTS: Between May 1992 and September 1998 the endoluminal method was used to repair arterial aneurysms in 304 patients at the Royal Prince Alfred Hospital, Sydney, a tertiary referral teaching hospital. The study focuses on 243 patients with true AAA who underwent primary repair. There were 17 females and 226 males with a mean age of 72 years. Co-morbidities leading to rejection for conventional open repair were present in 83 patients. The criteria for inclusion included a segment of thrombus-free aorta between the lowermost renal artery and the commencement of the aneurysm of 1.5 cm or greater and iliac arteries that allowed access to the aorta from the groin. The technique involved the delivery of an endograft into the abdominal aorta by means of a sheath inserted through the femoral or iliac artery. Laparotomy associated with conventional open repair was avoided. Outcome measures included clinical examination and contrast-enhanced computed tomography (CT) within 10 days, at 6, 12, 18 months after operation and then annually thereafter. RESULTS: Endografts were successfully deployed in 226 patients. In the remaining 17 patients endoluminal repair was converted to open repair. There were 8 deaths within 30 days of operation giving a perioperative mortality rate of 3.3%. The two studies presented to the Society for Vascular Surgery concern: (i) a concurrent comparison of the endoluminal versus open methods of treating AAA; and (ii) a comparison of adverse events following endoluminal repair of AAA during two consecutive periods of time.     

The measurement of abdominal aortic aneurysms.

A study was made of the accuracy of different methods currently used in assessing the transverse diameter of abdominal aortic aneurysms. The maximum transverse diameter of the abdominal aorta was estimated by clinical palpation, plain radiology, ultrasonography and aortography, in a group of 47 patients who were subjected to either a surgical exploration or elective aneurysm resection. The results of these estimations were compared with the actual measurements obtained during the surgical procedure. Measurements of aortic wall calcification seen on the plain X-ray film correlated best with the operative findings. However, calcification was seen in only 30% of the patients. Ultrasonography was almost universally applicable as a technique of assessing aortic size and was found to be a reliable technique for measuring the aortic diameter.     

Histoplasma infection of abdominal aortic aneurysms.

Fungal endarteritis resulting from progressive disseminated histoplasmosis may cause arterial aneurysms, or lead to infection of pre-existing aneurysms. Three patients with Histoplasma capsulatum infections of abdominal aortic aneurysms are reported. All had previous disseminated histoplasmosis and atherosclerotic peripheral vascular disease. All were considered cured of systemic infection when their aneurysms were discovered. Atherosclerotic vascular lesions may become infected during the course of systemic fungal disease and may serve as a haven for viable organisms in patients whose dissemination recurs despite seemingly adequate antifungal therapy. In treating these patients, resection of all infected arterial tissue, revascularization through uninfected tissues, and long-term antimicrobial therapy are recommended.     

Computed tomography of abdominal aortic aneurysms.

Computed tomography is an excellent non-invasive method for visualization of the size and extent of abdominal aortic aneurysms. It demonstrates the size of the lumen and the amount of thrombus in the aneurysm, and detects complications such as dissection and leakage.     

Laparoscopic surgery for abdominal aortic aneurysms

Background: Laparoscopic surgery for infrarenal aortic aneurysms is based on the principle of retroperitoneal exclusion of the aneurysm sac with aortofemoral or aortoiliac bypass. Methods: Of 22 patients who met the selection criteria, 20 successfully underwent laparoscopic aortic surgery at Morristown Memorial Hospital between February and October 1997. Technical elements and steps of this operation are described and illustrated. Results: Within 30 days of surgery, 2 patients died and 9 had various major and minor perioperative complications. As a group, the laparoscopic patients had less postoperative pain, needed fewer hours of ventilator support, had shorter intensive care unit (ICU) and hospital lengths of stay, and resumed diet and normal activity earlier than the historical norms for patients undergoing transabdominal or retroperitoneal aortic resections at the same institution. Conclusions: These early observations suggest that the laparoscopic treatment of infrarenal abdominal aneurysms may have several significant potential benefits. Long-term results and randomized prospective studies with patients matched by risk stratification will be needed to confirm these impressions. Received: 23 June 1997/Accepted: 11 December 1997     

Misdiagnosis of ruptured abdominal aortic aneurysms.

Ruptured abdominal aortic aneurysm is a surgical emergency with a high mortality rate even when diagnosed and repaired immediately. We retrospectively reviewed 152 cases of ruptured abdominal aneurysms to identify the incidence of misdiagnosis leading to a delay in treatment, the most frequent misdiagnoses, and the outcome in this group of patients. Forty-six (30%) were initially misdiagnosed. The most common misdiagnoses were renal colic, diverticulitis, and gastrointestinal hemorrhage. The most common initial physical findings in misdiagnosed patients were abdominal pain (70%), shock (57%), and back pain (50%). A pulsatile abdominal mass was found in only 26% of misdiagnosed patients versus 72% of patients correctly diagnosed (p less than 0.005). Misdiagnosed ruptured abdominal aneurysm had a 44% mortality rate, which was not significantly different from patients correctly diagnosed (58%, p = 0.34). The lack of difference in mortality rates is most likely due to preselection of those misdiagnosed patients who were able to withstand the delay in diagnosis and survive to surgical treatment. The 30% incidence of misdiagnosis in this series suggests that it is frequently a difficult diagnosis to make and must be considered in elderly patients, especially men, who are admitted with abdominal pain and/or back pain.     

Ruptured abdominal aortic aneurysms

Eighty two aortic replacements of ruptured abdominal aortic aneurysms have been performed during the last 6 years. There were 72 male and 10 female patients, and the average age was 71.33 years. Hemorrhagic shock on the admission was observed in 45 patients, and 13 have been operated urgently without any diagnostic procedures. The transperitoneal approach have been used for the operation. Two aorto duodenal and one aorto caval fistulas, have been found. Only exploration (three patients died immediately after laparotomy and 6 after cross clamping) has been done in 9 cases, and the aortic replacement in 70 cases (27 with tubular, and 43 with bifurcated graft). In 3 cases and axillobifemoral bypass had to be done. During the operation eleven patients died, and 30 in postoperative period, during the period between one and 40 days. Total intrahospital mortality rate was 50%, compared with 3.5% for 250 electively operated patients with abdominal aortic aneurysms in same period. In postoperative period the most important cause of death was multiple organs failures. Statistically significant greater mortality rate (p > 0.01%) was found in cases of late operative treatment, hemorrhagic shock, intra-operational bleeding, ruptured front wall, suprarenal cross clamping and in patients older than 75 year. In complicated cases such as juxtarenal aneurysm, 3 sutures parachute technique for proximal anastomosis, a temporary transection of the left renal vein, and intraaortal balloon occlusive catheter for proximal bleeding control are recommended.     

Inflammatory abdominal aortic aneurysms

In a series of 517 operations for abdominal aortic aneurysm from 1971 to 1988 there were 45 cases (8.7%) with an inflammatory aneurysm with a typical thick glistening whitish fibrous layer. Almost two-third of the patients had rather severe chronic or acute progressive pain in the abdomen, the back or the flank. Unilateral (7) or bilateral (2) hydronephrosis due to ureteral compression occurred in 9 patients (20%). A diagnosis of inflammatory aneurysm was made preoperatively only in 10 patients. In 8 of the 9 patients with hydronephrosis ureterolysis was done, unilaterally (6) or bilaterally (2). After ureterolysis all had complete resolution of the hydronephrosis. Preoperative diagnostic methods are excretory urography, showing medial deviation, ultrasonography and CT-scanning of the abdominal aorta. All patients with an inflammatory aneurysm should undergo aortic replacement to prevent rupture and achieve pain relief. Ureterolysis in cases of hydronephrosis is strongly recommended and may be performed safely and with excellent results.     

Familial abdominal aortic aneurysms

The case histories of three brothers, the only siblings of one family, all of whom underwent surgery for the treatment of a previously asymptomatic ruptured abdominal aortic aneurysm, are recorded. The possibility of underlying constitutional and hereditary factors is discussed and the suggestion of a primary familial incidence of atheromatous, nondissecting aortic aneurysm is raised.     

Ruptured abdominal aortic aneurysms

A series of 180 consecutive patients with ruptured aortic aneurysms has been studied to determine the causes of death. 18% died before operation could be carried out, 8% proved inoperable and a further 10.5% died before operation could be completed. Overall mortality was 75%. By multivariate analysis, the most significant preoperative features influencing survival were a systolic BP less than 80 mmHg on admission and a history of hypertension, angina or myocardial infarct. The mortality increased with increasing age. Administration of fresh frozen plasma preoperatively significantly increased survival. However, we could not identify a single group of patients for whom the outcome was inevitably fatal.