Elective treatment of abdominal aortic aneurysms

The PTFE Y-graft: One Year Experience in 21 Patients

21 patients had aortoiliac reconstructions for aortic aneurysms or occlusive disease with the new PTFE Y-graft during the past 12 months. 2 patients in the aneurysm group with additional renal artery reconstruction suffered postoperative myocardial infarction and subsequently died. 2 patients older than 80 years died after aneurysm repair in cause of graft infection, respectively respiratory insufficiency. All grafts (n = 17) are functioning well or did so until death of the patient (n=4). The obvious advantage of the PTFE Y-graft is the fact, that there is no need of preclotting. Suture line — even using 4-0 material at the proximal anastomosis — and graft body is absolutely tight and no blood loss has to be expected from this site. However positioning of the left limb of the y-graft can be difficult in patients with right sided extraperitoneal approach and proximal side end anastomosis. Performing an end-end anastomosis can overcome this problem. For occlusion of the prosthesis limbs two vascular clamps on each side are needed to control blood flow within the rather stiff graft. Immediate and short term function is excellent. There was no material specific complication noted until now. Further longterm experience is necessary to evaluate the definitive quality of this new prosthetic material after some years.

Familial Incidence of Abdominal Aortic Aneurysms

The rupture of an abdominal aortic aneurysms (AAAs) is associated with a mortality rate exceeding 50%. To reduce this figure it is necessary to increase the frequency of early diagnosis and elective surgery. Screening the general population for occult AAAs has proven cost ineffective. Only by identifying high-risk subgroups will screening programs be improved. The aim of this report was to investigate by ultrasonography the prevalence of previously unknown aortic dilatations among first-degree relatives (parents, siblings, and children) of patients operated on for AAAs.

Ninety-one (52.6%) of the 173 living first degree-relatives of 51 patients who underwent AAA resection were submitted to an aortoiliac ultrasonographic examina tion to establish aortic diameter and morphology. There was at least 1 first-degree relative with an AAA (multiplex family) in 10 families (19.6%) before ultrasound screening. With ultrasound a previously unknown infrarenal aortic dilatation was detected in 14 subjects (9 men/5 women; 10 siblings and 4 children) of 12 different families. Specifically, these aortic dilatations consisted of 10 AAAs (diameters ranged from 2.6 to 4.3 cm) and 4 aortic blebs. These occult aortic dilatations were located in 50% of cases in the lower third of the infrarenal abdominal aorta. The cumulative incidence of multiplex families was 35.3%. This study suggests a familial tendency to have an important etiologic role in the formation of AAAs. Family screening of, above all, male siblings older than forty-five years will help identify occult AAAs and reduce the mortality rates associated with their rupture.

Anesthesia for Open Abdominal Aortic Aneurysm Repair

Abdominal aortic aneurysms (AAAs) are the 13th leading cause of death in the United States 1 and approximately 40,000 patients undergo elective AAA repair each year.2 With the population aging, this number is expected to increase. Although the use of endovascular AAA repair is becoming more common, open repair, first reported by Dubost et al. in 1951 remains the gold standard.2 This chapter will review the etiology, risk factors, diagnosis, pathophysiology, operative technique, perioperative management, and postoperative complications of patients undergoing open AAA repair.

Elective Versus Ruptured Abdominal Aortic Aneurysm Repair: A 1-Year Cost-Effectiveness Analysis

Abdominal aortic aneurysm (AAA) is a life-threatening condition with an overall mortality of 80%. It predominantly affects men 65-74 years of age and is caused by focal distension of the main blood vessel in the abdomen. Most patients go undetected until their aneurysm ruptures. Controversy surrounds the most appropriate form of screening for AAA. Currently, screening is only carried out selectively in patients with peripheral vascular disease. Some patients have their AAA detected incidentally, whilst ultrasound examination of the abdomen is carried out for other indications. These patients have the opportunity to undergo surveillance or elective surgery. The mortality rate of emergency surgical intervention following rupture (50%) is far worse in comparison to that of patients undergoing planned intervention under specialist vascular surgeons (5%). Despite improvements in outcomes from elective intervention for AAA as a result of specialisation, the overall mortality from this condition remains very high (80%) as the commonest presentation of an AAA is rupture. Screening all men aged 65-74 years is considered too costly in the current economic climate. However the cost difference between elective repair and emergency repair of AAA must be considered given that the outcome from elective AAA repair is far superior to that following ruptured AAA repair. Our objective was to retrospectively collect costs and outcomes of elective and emergency AAA repair in order to carry out a cost-effectiveness analysis. Four multiprofessional teams in accident and emergency, operation theatres, intensive care, and surgical wards at the Kent and Canterbury Hospital were selected from health-care professionals including doctors, managers, nurses, and clerical staff with the purpose of obtaining costs. Detailed cost data collection sheets were prepared to calculate costs, which included staff costs, consumables including drugs, intravenous fluids, equipment, investigations, laundry, catering, and stationery. An inventory of costs per item was obtained, and the total cost was calculated from the number of items used. Outcomes were measured in terms of survival. The total costs of emergency AAA repair were pounds sterling 96,700.69, with a cost per life saved of pounds sterling 24,175.17. The total cost of elective AAA repair was pounds sterling 76,583.22, with a cost per life saved of pounds sterling 5,470.23. Emergency intervention for AAA was found to cost five times more than a planned intervention per life saved per year.

Cost-effectiveness of different screening strategies for abdominal aortic aneurysm

OBJECTIVE

The primary objective of this study was to develop a simulation model to assess the cost-effectiveness of different screening strategies for abdominal aortic aneurysms (AAAs) in men.

METHODS

A systematic review of the literature was conducted for different screening strategies in terms of age (60, 65, or 70 years) and risk profiles (all men or specific high-risk groups) of the screened population, and rescreening after 5 or 10 years. These data were analyzed in a Markov simulation cohort model.

RESULTS

The cost per life year gained for different screening strategies ranged from US 8,309 dollars to US 14,084 dollars and was estimated at US 10,474 dollars when 65-year-old men were screened once. Screening 60-year-old men was equally cost-effective, with the advantage of more life years gained. We demonstrated a trade-off between high prevalence of AAA and lower life expectancy, eliminating the expected benefits of screening high-risk groups such as smokers (US 10,695 dollars) or cardiovascular patients (US 10,392 dollars). Assuming general population utility resulted in a cost per quality-adjusted life year (QALY) gained of US 13,900 dollars, whereas a hypothetical 5% reduction in utility among men with a screening-detected AAA raised the cost per QALY gained to US 75,100 dollars.

CONCLUSION

This Markov model, which was based on a systematic review of the literature, supplied information on the estimated cost-effectiveness of different screening strategies. Screening men for AAA may be cost-effective in the long-term. Different screening strategies and quality-of-life effects related to screening for AAA need to be evaluated in future clinical studies.

Abdominal aortic aneurysm rupture rates: a 7-year follow-up of the entire abdominal aortic aneurysm population detected by screening

PURPOSE

The goal of the current study was to identify the risk of rupture in the entire abdominal aortic aneurysm (AAA) population detected through screening and to review strategies for surgical intervention in light of this information.

METHODS

Two hundred eighteen AAAs were detected through ultrasound screening of a family practice population of 5394 men and women aged 65 to 80 years. Subjects with an AAA of less than 6.0 cm in diameter were followed prospectively with the use of ultrasound, according to our protocol, for 7 years. Patients were offered surgery if symptomatic, if the aneurysm expanded more than 1.0 cm per year, or if aortic diameter reached 6.0 cm.

RESULTS

The maximum potential rupture rate (actual rupture rate plus elective surgery rate) for small AAAs (3.0 to 4.4 cm) was 2.1% per year, which is less than most reported operative mortality rates. The equivalent rate for aneurysms of 4.5 to 5.9 cm was 10.2% per year. The actual rupture rate for aneurysms up to 5.9 cm using our criteria for surgery was 0.8% per year

CONCLUSION

In centers with an operative mortality rate of greater than 2%, (1) surgical intervention is not indicated for asymptomatic AAAs of less than 4.5 cm in diameter, and (2) elective surgery should be considered only for patients with aneurysms between 4.5 and 6 cm in diameter that are expanding by more than 1 cm per year or for patients in whom symptoms develop. In centers with elective mortality rates of greater than 10% for abdominal aortic aneurysm (AAA) repair, the benefit to the patient of any surgical intervention for an asymptomatic AAA of less than 6.0 cm in diameter is questionable.

Prognostic factors in elective aortic reconstructive surgery

BACKGROUND

The present study was carried out to determine the risk factors associated with peri-operative mortality and long-term survival in patients undergoing abdominal aortic reconstructive surgery (ARS).

METHODS

A retrospective review was performed of the case notes of all patients having ARS at a university teaching hospital during a 5.5-year period, and their details entered onto a pro forma.

RESULTS

A total of 252 patients underwent ARS between July 1989 and December 1994. The peri-operative mortality was 7.5%. The most frequent adverse events were cardiac events, accounting for 8 (42%) of the peri-operative deaths. The risk of a peri-operative cerebrovascular accident was low (n = 3, 1.2%) as was the risk of peri-operative renal failure requiring dialysis (n = 3, 1.2%). Factors independently linked to increased peri-operative mortality included moderate-to-severe hypertension (P = 0.05, odds ratio = 3.54), those with renal impairment (P = 0.05, odds ratio = 2.69), and blood transfusion requirements (P < 0.001, odds ratio = 1.26). Long-term survival was independently shortened by occlusive disease (P = 0.004, hazard ratio = 2.78) and ischaemic heart disease (P < 0.001, hazard ratio = 3.58).

CONCLUSIONS

The risks of ARS were significantly increased in patients with severe hypertension, those with renal impairment and those requiring blood transfusion. Long-term survival was shortened for those patients with occlusive aortic disease and ischaemic heart disease. These risk factors should be carefully assessed in each patient before performing elective ARS.

Vascular ultrasonography

Although vascular ultrasonography has been established as an essential diagnostic tool in many clinical settings, its role in the emergency department patient population is uncertain. Preliminary reports of emergency physician--directed ultrasonography are promising. Further studies are needed to establish its reliability and suitability in the emergency department setting.

Graft-related complications after abdominal aortic aneurysm repair: reassurance from a 36-year population-based experience

PURPOSE

Graft-related complications must be factored into the long-term morbidity and mortality rates of abdominal aortic aneurysm (AAA) repair. However, the true incidence may be underestimated because some patients do not return to the original surgical center when a problem arises.

METHODS

To minimize referral bias and loss to follow-up, we studied all patients who underwent AAA repair between 1957 and 1990 in a geographically defined community where all AAA operations were performed and followed by a single surgical practice. All patients who remained alive were asked to have their aortic grafts imaged.

RESULTS

Among 307 patients who underwent AAA repair, 29 patients (9.4%) had a graft-related complication. At a mean follow-up of 5.8 years (range, < 30 days to 36 years), the most common complication was anastomotic pseudoaneurysm (3.0%), followed by graft thrombosis (2.0%), graft-enteric erosion/fistula (1.6%), graft infection (1.3%), anastomotic hemorrhage (1.3%), colon ischemia (0.7%), and atheroembolism (0.3%). Complications were recognized within 30 days after surgery in eight patients (2.6%) and at late follow-up in 21 patients (6.8%). These complications were observed at a median follow-up of 6.1 years for anastomotic pseudoaneurysm, 4.3 years for graft-enteric erosion, and 0.15 years for graft infection. Kaplan-Meier 5- and 10-year survival free estimates were 98% and 96% for anastomotic pseudoaneurysm, 98% and 95% for combined graft-enteric erosion/infection, and 98% and 97% for graft thrombosis.

CONCLUSIONS

This 36-year population-based study confirms that the vast majority of patients who undergo standard surgical repair of an abdominal aortic aneurysm remain free of any significant graft-related complication during their remaining lifetime.

Endoluminal repair of abdominal aortic aneurysms

OBJECTIVE

To review the outcome of endoluminal repair of abdominal aortic aneurysm.

PATIENTS

Twelve patients with abdominal aortic aneurysms (mean diameter, 5 cm; range, 4.4-7.8 cm) were selected according to strict criteria relating to the morphology of the aneurysm and iliac arteries. The aneurysms all had a proximal neck between the renal arteries and the aneurysm and a distal neck between the aneurysm and the bifurcation of the aorta. The iliac arteries were not tortuous and were 8 mm or greater in diameter.

INTERVENTION

The aneurysm was repaired with a graft stent device introduced into the aorta via a sheath in the femoral artery.

RESULTS

Successful endoluminal repair was achieved in 10 of 12 patients (83%). The two patients in whom the endoluminal repair was abandoned were treated by standard open repair. All patients have since had an aortogram and duplex ultrasound examination to confirm exclusion of the aneurysm from the general circulation (mean period of follow-up, seven months). There have been no deaths.

CONCLUSION

Abdominal aortic aneurysms conforming to strict morphological criteria can be treated safely and successfully by this minimally invasive endoluminal method.

Perioperative management and outcome of patients having cardiac surgery combined with abdominal aortic aneurysm resection

Patients with abdominal aortic aneurysms (AAA) have a high incidence of associated cardiac disease. If a patient presents with both severe coronary artery disease and a large AAA, a staged procedure of cardiac surgery (CS) followed by AAA resection may present too great a risk of aneurysm rupture and death. A combined procedure may be recommended in this circumstance; however, the literature contains only individual successful case reports of such a procedure. A series of 10 patients who underwent CS and AAA repair to define the risks and outcome of this complex patient population is presented. Methods used included a retrospective analysis of hospital chart data from patients undergoing combined CS and AAA resection from 1980 to the present at this institution. The data analyzed included age, sex, chief complaint, past medical history, indications for surgery, abdominal aneurysm size, coronary anatomy, valvular pathology, preoperative left ventricular function, anesthetic agent and dose, order of surgery, prebypass complications, intraoperative complications, cardiopulmonary bypass time, aortic cross-clamp time, abdominal aortic cross-clamp time, blood product use, and postoperative complications. Seven of the 10 patients had a successful outcome (S group), whereas 3 of the 10 patients died postoperatively (D group). The staged procedure of first performing CS and then the AAA resection has a combined operative mortality of 4%. When the nature of both lesions is severe and a combined procedure is necessary, there is an associated in-hospital mortality of approximately 30% at this institution. The S group patients had an unremarkable postoperative course with a relatively short hospital stay when compared to the staged procedure.

Supraceliac clamping in the surgical treatment of abdominal aortic aneurysm. An experimental study in dogs

Previous reports have suggested the use of supraceliac aortic clamping in the surgical treatment of abdominal aortic aneurysm of difficult approach. The objective of the present report was to study the hepatic and renal metabolic changes of three groups of dogs submitted to temporary clamping (30 minutes) of the abdominal aorta at three different levels: below the renal arteries, infrarenal group (8 dogs); above the renal arteries, suprarenal group (9 dogs); above the celiac artery, supraceliac group (9 dogs). Blood bilirubin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea nitrogen, and creatinine levels were measured before clamping and 5 minutes and 24 hours after reperfusion of the aorta. Bilirubin levels remained unchanged 5 minutes and 24 hours after reperfusion in all three groups. Alkaline phosphatase levels were significantly increased in all three groups 24 hours after reperfusion. ALT levels increased significantly in the supraceliac group and AST levels increased significantly in the infrarenal and supraceliac groups 24 hours after reperfusion of the aorta. However, despite these significant increases after reperfusion, the levels of these hepatic enzymes were still within the normal range for dogs. Urea nitrogen and creatinine levels showed that renal function did not change in any of the three groups. We conclude that supraceliac, infrarenal or suprarenal aortic clamping for 30 minutes do not promote any important changes in the hepatic or renal function of dogs.

Vascular disease in the elderly patient

At a time of potentially dramatic changes in health care policy in this country, and in view of the necessity for health care cost containment, physicians are expected to exercise serious introspection in the selection of treatment for the elderly patient with peripheral arterial disease. These decisions should be made while acknowledging that it is the goal of the health-care provider "to postpone chronic illness, to maintain vigor, and to slow social and psychological involution." For the elderly patient with an abdominal aortic aneurysm, with significant carotid disease, or with limb-threatening peripheral ischemia, the evidence is compelling that timely surgical intervention in properly selected patients is well tolerated and will satisfy this goal.

Transfemoral intraluminal graft implantation for abdominal aortic aneurysms

This study reports on animal experimentation and initial clinical trials exploring the feasibility of exclusion of an abdominal aortic aneurysm by placement of an intraluminal, stent-anchored, Dacron prosthetic graft using retrograde cannulation of the common femoral artery under local or regional anesthesia. Experiments showed that when a balloon-expandable stent was sutured to the partially overlapping ends of a tubular, knitted Dacron graft, friction seals were created which fixed the ends of the graft to the vessel wall. This excludes the aneurysm from circulation and allows normal flow through the graft lumen. Initial treatment in five patients with serious co-morbidities is described. Each patient had an individually tailored balloon diameter and diameter and length of their Dacron graft. Standard stents were used and the diameter of the stent-graft was determined by sonography, computed tomography, and arteriography. In three of them a cephalic stent was used without a distal stent. In two other patients both ends of the Dacron tubular stent were attached to stents using a one-third stent overlap. In these latter two, once the proximal neck of the aneurysm was reached, the sheath was withdrawn and the cephalic balloon inflated with a saline/contrast solution. The catheter was gently removed caudally towards the arterial entry site in the groin to keep tension on the graft, and the second balloon inflated so as to deploy the second stent. Four of the five patients had heparin reversal at the end of the procedure. We are encouraged by this early experience, but believe that further developments and more clinical trials are needed before this technique becomes widely used.

The spontaneous course of small abdominal aortic aneurysms. Aneurysmal growth rates and life expectancy

Since abdominal ultrasonography has become a routine diagnostic procedure, increasing numbers of small asymptomatic abdominal aortic aneurysms are detected incidentally. Of 128 patients (108 male, 20 female) with abdominal aortic aneurysms, 96 patients were observed clinically and by repeated ultrasound studies for an average of 3.47 years, adding up to a total observation period of 333 patient-years. Among these 96 patients, 72 had small aneurysms (averaged diameters less than 5 cm). Three of them were lost to follow up. None of the remaining 69 patients died from rupture, 20 died from other causes and 8 patients were successfully operated. Of the patients with a large aneurysm one was lost to follow up. Five patients of the remaining 23 died as a result of rupture, 7 were successfully operated. The average growth rate of small aneurysms was 0.18 cm/year, whereas the larger aneurysms showed a growth rate of 0.28 cm/year (diameter). The survival rate of patients with small aneurysms was 94% after one year, 80% after 3 years, and 73% after 5 years, indicating that life expectancy is reduced in patients with an aneurysm of the abdominal aorta, but not because of complications of the aneurysm.

Abdominal pain: a surgical audit of 1190 emergency admissions

In an audit of 1190 emergency admissions with abdominal pain (1166 patients) in a general surgical unit, the diagnosis was non-specific abdominal pain (NSAP) in 415 (35 per cent), acute appendicitis in 200 (17 per cent) and intestinal obstruction in 176 (15 per cent). The largest number of admissions occurred in the age groups 10-29 years (31 per cent) and 60-79 years (29 per cent). Surgical operations were performed in 551 patients (47 per cent) and there was a 16 per cent incidence of unnecessary appendicectomy (22 per cent in the age group 20-29 years). Fifty-one deaths resulted in a 30-day hospital mortality rate of 4.4 per cent and a perioperative mortality rate of 8 per cent. The mortality rate increased significantly in patients aged greater than or equal to 60 years, and patients aged 80-89 years had a perioperative mortality rate of 20 per cent. The causes of perioperative death included laparotomy for inoperable disease (28 per cent), ruptured abdominal aortic aneurysm (23 per cent), perforated peptic ulcer (16 per cent) and colonic resections (14 per cent). The perioperative mortality rates for ruptured aneurysm and perforated ulcer were 71 and 23 per cent respectively. The duration of inpatient stay increased significantly with the age of the patients, including those with NSAP. The results of the study indicate a need to review the methods of management of ruptured aortic aneurysm and perforated peptic ulcer, the methods of diagnosis of appendicitis, particularly in young females, and the factors that determine the duration of stay of patients suffering from NSAP.

Intraoperative management of abdominal aortic aneurysms. The anesthesiologist's viewpoint

Factors that influence the choice of anesthetic, monitoring methods, and fluid management for aneurysm repair are reviewed, with particular attention to epidural anesthesia and analgesia and the pulmonary artery catheter. Management of bleeding, renal preservation, temperature control, and myocardial ischemia are discussed, and special anesthetic issues associated with ruptured aneurysms and juxtarenal and suprarenal surgery are summarized.

Ruptured abdominal aortic aneurysms: experience with 70 cases

During the period 1965-1983, 270 patients underwent resection of abdominal aortic aneurysm. In 70 patients (26%) the aneurysm was ruptured. Overall hospital mortality of patients with ruptures was 34%. Five patients died before the graft could be completed. Common denominators associated with mortality were hypotension, renal failure, cardiac arrest, and postoperative hemorrhage. The average age over the first 10 years was 68, but subsequently, has risen gradually, with a corresponding increase in mortality despite improved surgical technique and postoperative care. Only with more widespread elective resections and earlier diagnosis of rupture followed by prompt operative management, can the outlook for patients with abdominal aortic aneurysm be improved.

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.

[Sonographic observation of the course of aneurysms of the abdominal aorta]

Forty-two patients with an abdominal aortic aneurysm that had not been treated surgically were repeatedly examined by ultrasonography. The average observation time of all patients was 3.1 years. The total observation period including follow-up times of all patients adds up to 129 "patient years". Within this time none of the 35 asymptomatic abdominal aneurysms with transversal diameters of maximally 5 cm ruptured. Three patients of seven with larger and symptomatic aneurysms died in consequence of a rupture. Small asymptomatic abdominal aortic aneurysms seem to have a better prognosis than previously supposed. The question whether all abdominal aneurysms should be operated on needs reconsideration, especially in the elderly.

Discordance in the sizing of abdominal aortic aneurysm and its significance

Much of the confusion surrounding the repair of asymptomatic abdominal aortic aneurysms related to inaccuracies in their measurement, both preoperatively and intraoperatively. Multiple measurements of aneurysms at operation have convinced us that the largest and least variable diameter is the anteroposterior diameter measured from aortic wall anteriorly to vertebral bodies posteriorly. This AP-to-spine distance is accurately predicted by ultrasonography to within 0.3 cm. Computerized tomography does no better. plain radiography is accurate but seldom applicable. When properly estimated, aneurysm size can be accurately determined preoperatively by either ultrasonography, computerized tomography, or plain radiography, in that order of preference. Since the decision to operate on asymptomatic aneurysms is based largely on their size, accurate preoperative estimation is essential.