In-hospital mortality from abdominal aortic surgery in Great Britain and Ireland: Vascular Anaesthesia Society audit

Preoperative cardiac assessment for patients with infrarenal abdominal aortic aneurysms: a survey of current practice by vascular surgeons in New South Wales and Australian Capital Territory

BACKGROUND

The reported mortality rate following open elective repair of abdominal aortic aneurysm (AAA) varies between 0 and 12%. Much of the mortality and major morbidity is caused by cardiac events. The evidence regarding best practice for cardiac assessment and optimization of this patient group is unclear. The aim of the present study was to evaluate current practice of cardiac risk factor assessment by vascular surgeons in New South Wales (NSW) and Australian Capital Territory (ACT) for patients undergoing open elective repair of infrarenal AAA.

METHODS

A postal questionnaire was sent to 46 surgeons in NSW and ACT identified as expressing a principal or major interest in vascular surgery. If no response was received within 3 weeks, a second questionnaire was sent and if no response was received after the second mailing, a telephone survey of non-responders was conducted. Data were collated regarding the importance of risk factors elicited by clinical history, preoperative investigation, referral for cardiological opinion, use of perioperative beta-blockade and the timing of aortic surgery in relation to coronary artery revascularization and acute myocardial infarction.

RESULTS

The overall response rate was 87% (40/46) and the median (range) response time was 14 (4-109) days. Only 22 of 40 and 23 of 40 surgeons consider diabetes mellitus or renal impairment, respectively, to be important when assessing cardiac risk and 34 of 40 surgeons do not employ a validated risk index in preoperative assessment. Sixteen of 40 surgeons refer all patients needing AAA repair to a cardiologist, while 24 of 40 would initiate cardiac investigations themselves (either stress electrocardiography, scintigraphy or echocardiography). Seventeen surgeons always or usually commenced perioperative beta-blockade with wide variations in the commencement (1 to > 28 days preoperatively) and duration (< 1 week to > 28 days postoperatively) of treatment. The timing of AAA repair following coronary revascularization ranged from < 1 week to 6 months and delay in surgical repair of AAA following myocardial infarction ranged from < 1 week to > 6 months.

CONCLUSION

Preoperative assessment of cardiac risk in patients for repair of AAA lacks consensus among vascular surgeons in NSW and ACT. The diversity of clinical practice may rest with the paucity of prospective trials published in the medical literature or the influence of local institutional facilities.

Cardiac risk stratification in patients undergoing endoluminal graft repair of abdominal aortic aneurysm: a single-institution experience with 365 patients

OBJECTIVE

Patients undergoing abdominal aortic aneurysm repair have a high incidence of coexisting cardiac disease. The traditional cardiac risk stratification for open abdominal aortic aneurysm surgery may not apply to patients undergoing endoluminal graft exclusion. The purpose of this study was to examine predictive risk factors for perioperative cardiac events.

METHODS

As part of multiple prospective endograft trials approved by the US Food and Drug Administration, data for 365 patients who underwent endoluminal graft repair from 1996 to 2001 were collected. Variables included for analysis were age and sex; history of smoking; presence of hypertension, diabetes mellitus, or renal insufficiency; Eagle clinical cardiac risk factors; American Society of Anesthesiologists index; type of anesthesia administered; estimated blood loss; preoperative hemoglobin level; preoperative use of beta-blocker therapy; duration of surgery; need for iliac artery conduit; and concomitant other vascular procedures. Univariate and multivariate logistic regression analysis were used to determine which variables were predictive of an adverse perioperative cardiac event, eg, Q wave and non-Q wave myocardial infarction (MI), congestive heart failure (CHF), severe arrhythmia, and unstable angina.

RESULTS

The study cohort included 322 men and 43 women (mean age, 74.2 years). Fifty-two (14.2%) postoperative cardiac events occurred: severe dysrhythmia in 15 patients (4.1%), MI in 14 patients (3.8%), non-Q wave MI in 8 patients (2.2%), CHF in 8 patients (2.2%), and unstable angina in 7 patients (1.9%). Univariate analysis demonstrated that age 70 years or older (P =.034), history of MI (P =.018), angina (P =.004), history of CHF (P <.001), two or more Eagle risk factors (P <.001), and lack of use of preoperative beta-blocker therapy (P =.005) were predictors of perioperative cardiac events. Multivariate analysis identified only age 70 years or older (P =.026), history of MI (P =.024) or CHF (P =.001), and lack of use of preoperative beta-blocker therapy (P =.007) as independent risk factors for an adverse cardiac event.

CONCLUSIONS

Age 70 years or older, history of MI or CHF, and lack of use of preoperative beta-blocker therapy are independent risk factors for perioperative cardiac events in patients undergoing endoluminal graft repair.

Value of the Glasgow Aneurysm Score in predicting the immediate and long-term outcome after elective open repair of infrarenal abdominal aortic aneurysm

BACKGROUND

This study aimed to explore the value of the Glasgow Aneurysm Score in predicting the immediate and long-term outcome after elective open repair of abdominal aortic aneurysm (AAA).

METHODS

Some 403 patients underwent elective open repair of an infrarenal AAA and were classified retrospectively according to the criteria of the Glasgow Aneurysm Score (risk score = (age in years) + (7 for myocardial disease) + (10 for cerebrovascular disease) + (14 for renal disease)).

RESULTS

Fourteen patients (3.5 per cent) died after operation, 23 (5.7 per cent) had a myocardial infarction and six (1.5 per cent) had a stroke. One hundred and nine patients (27.0 per cent) experienced severe postoperative complications. The Glasgow Aneurysm Score was predictive of postoperative death (area under the receiver-operator characteristic curve (AUC) 0.80, 95 per cent confidence interval (c.i.) 0.71 to 0.90), severe postoperative complications (AUC 0.67, 95 per cent c.i. 0.61 to 0.73), myocardial infarction (AUC 0.72, 95 per cent c.i. 0.62 to 0.82), myocardial infarction-related postoperative death (AUC 0.78, 95 per cent c.i. 0.63 to 0.94) and stroke (AUC 0.84, 95 per cent c.i. 0.74 to 0.95). Univariate analysis showed that this risk index was also predictive of long-term survival.

CONCLUSION

The Glasgow Aneurysm Score is a good predictor of outcome after elective open repair of AAA. Its simplicity and accuracy make it useful for preoperative risk stratification.

Myocardial ischaemia precipitated by acute normovolaemic haemodilution

Acute normovolaemic haemodilution (ANH) is widely used as part of a blood conservation strategy to minimize the use of allogenic blood in the peri-operative period. Its role has not been proven in a prospective randomized trial. The potential benefits must not blind clinicians to the possible hazards. We report a life-threatening complication of ANH prior to induction of anaesthesia for aortic aneurysm repair.

Guidelines for the treatment of abdominal aortic aneurysms. Report of a subcommittee of the Joint Council of the American Association for Vascular Surgery and Society for Vascular Surgery

Decision-making in regard to elective repair of abdominal aortic aneurysms (AAA) requires careful assessment of factors that influence rupture risk, operative mortality, and life expectancy. Individualized consideration of these factors in each patient is essential, and the role of patient preference is of increasing importance. It is not possible or appropriate to recommend a single threshold diameter for intervention which can be generalized to all patients. Based upon the best available current evidence, 5.5 cm is the best threshold for repair in an "average" patient. However, subsets of younger, good-risk patients or aneurysms at higher rupture risk may be identified in whom repair at smaller sizes is justified. Conversely, delay in repair until larger diameter may be best for older, higher-risk patients, especially if endovascular repair is not possible. Intervention at diameter <5.5 cm appears indicated in women with AAA. If a patient has suitable anatomy, endovascular repair may be considered, and it is most advantageous for older, higher-risk patients or patients with a hostile abdomen or other technical factors that may complicate standard open repair. With endovascular repair, perioperative morbidity and recovery time are clearly reduced; however, there is a higher reintervention rate, increased surveillance burden, and a small but ongoing risk of AAA rupture. There is no justification at present for different indications for endovascular repair, such as earlier treatment of smaller AAA. Until long-term outcome of endoluminal repair is better defined and results of randomized trials available, the choice between endovascular and open repair will continue to rely heavily on patient preference.

A myth exposed: fast growth in diameter does not justify precocious abdominal aortic aneurysm repair

OBJECTIVES

fast growth of abdominal aortic aneurysm (AAA) diameter is claimed to be an indication for repair. We investigated the validity of this claim.

METHODS

between January 1988 and October 2000, 277 patients have had duplex sonography at six-monthly intervals in our aneurysm surveillance programme. During this period fast AAA growth was not an indication for operation in our unit.

RESULTS

we identified 63 patients whose aneurysms had grown 0.5 cm or more in 6 months. Thirty-one of the 63 patients had aneurysms measuring 5.5 cm or greater in anterior-posterior diameter after the fast growth and all have been operated on unless deemed not fit due to anaesthetic risk. The remaining 32 patients continued in surveillance for a total of 50 patient years and none had rupture of their aneurysm. The calculated 95% confidence interval for the risk of rupture was 0-6 per 100 patient years. Six patients, who would have been operated on if fast growth had been an indication, have been spared surgery of whom 3 died and 3 became unfit. Nine patients remained in surveillance at the end of the study.

CONCLUSION

our data support the view that rapid increase in AAA diameter is not an indication for elective AAA repair.

Internal iliac artery embolization with bilateral occlusion before endovascular aortoiliac aneurysm repair-clinical outcome of simultaneous and sequential intervention

PURPOSE

To retrospectively evaluate the clinical outcome of patients after simultaneous or sequential internal iliac artery (IIA) embolization for bilateral IIA occlusion.

MATERIALS AND METHODS

Sixteen patients (65-88 y; mean, 75.6 y; two women), 11 with aortobiiliac aneurysms, three with bilateral common iliac artery (CIA)/IIA aneurysms, and two with unilateral CIA/IIA aneurysms, underwent IIA occlusion before endovascular aortoiliac repair. Eight patients underwent simultaneous bilateral IIA embolization before endovascular aortic repair (EVAR). Eight patients had sequential bilateral IIA occlusion. The outcome was assessed by clinical follow-up.

RESULTS

There were no severe ischemic complications such as buttock necrosis or acute bowel, bladder, or spinal cord ischemia. Early ischemic complications occurred in 25% (buttock/thigh claudication, n = 3, 18.8%; and sexual dysfunction, n = 1, 6.2%) and had an onset not later than 6 months after intervention: buttock claudication resolved (n = 2) or persisted after aggravation by inferior mesenteric artery embolization for type II endoleak (n = 1). Impotence in a fourth patient persisted. The ischemic complication rate after 6 months was 30% (three of 10) because of a fifth patient who developed ischemic colitis with aggravation of ischemic heart disease after 15 months. The mean follow-up duration was 19.7 months. Patients with simultaneous embolization had a lower complication rate than those with sequential embolization (one of eight [12.5%] vs four of eight [50%], respectively).

CONCLUSIONS

IIA embolization for bilateral IIA occlusion can be performed with a complication rate comparable with results of previous studies of unilateral IIA embolization. Chronic buttock claudication may be aggravated by embolization of aortic side branches. Late complications can have an insidious course and be initiated by low-output cardiac failure. Bilateral IIA occlusion is recommended only in patients who are considered unfit for aortic surgery.