The long-term survival rates of patients after repair of abdominal aortic aneurysms

Systematic Review and Meta-analysis of Factors Influencing Survival Following Abdominal Aortic Aneurysm Repair

BACKGROUND

Predicting long-term survival following repair is essential to clinical decision making when offering abdominal aortic aneurysm (AAA) treatment. A systematic review and a meta-analysis of pre-operative non-modifiable prognostic risk factors influencing patient survival following elective open AAA repair (OAR) and endovascular aneurysm repair (EVAR) was performed.

METHODS

MEDLINE, Embase and Cochrane electronic databases were searched to identify all relevant articles reporting risk factors influencing long-term survival (≥1 year) following OAR and EVAR, published up to April 2015. Studies with <100 patients and those involving primarily ruptured AAA, complex repairs (supra celiac/renal clamp), and high risk patients were excluded. Primary risk factors were increasing age, sex, American Society of Anaesthesiologist (ASA) score, and comorbidities such as ischaemic heart disease (IHD), cardiac failure, hypertension, chronic obstructive pulmonary disease (COPD), renal impairment, cerebrovascular disease, peripheral vascular disease (PVD), and diabetes. Estimated risks were expressed as hazard ratio (HR).

RESULTS

A total of 5,749 study titles/abstracts were retrieved and 304 studies were thought to be relevant. The systematic review included 51 articles and the meta-analysis 45. End stage renal disease and COPD requiring supplementary oxygen had the worst long-term survival, HR 3.15 (95% CI 2.45-4.04) and HR 3.05 (95% CI 1.93-4.80) respectively. An increase in age was associated with HR of 1.05 (95% CI 1.04-1.06) for every one year increase and females had a worse survival than men HR 1.15 (95% CI 1.07-1.27). An increase in ASA score and the presence of IHD, cardiac failure, hypertension, COPD, renal impairment, cerebrovascular disease, PVD, and diabetes were also factors associated with poor long-term survival.

CONCLUSION

The result of this meta-analysis summarises and quantifies unmodifiable risk factors that influence late survival following AAA repair from the best available published evidence. The presence of these factors might assist in clinical decision making during discussion with patients regarding repair.

Risk factors affecting survival after surgical repair of ruptured abdominal aortic aneurysm

PURPOSE

The purpose of this study is to identify the risk factors affecting the high mortality rates associated with the treatment of ruptured abdominal aortic aneurysm (AAA).

METHODS

In this retrospective study, the subjects consisted of 105 patients who underwent repair of ruptured AAA at our institution from December 1984 to March 2012. We compared the patients of ruptured AAA in survival group with those in death group to evaluate the clinical factors in ruptured AAA mortality.

RESULTS

The operative and in-hospital mortality of ruptured AAA patients was 22.9% compared with 1.9% for that of non-ruptured AAA patients. The mean hemoglobin level was significantly lower in death group than in survival group. Intraoperative bleeding volume was significantly higher in death group than in survival group. Cox proportional hazard analysis showed that level 3 or 4 according to the Rutherford classification, preoperative hemoglobin level of less than 9.0 g/dl, intraoperative blood loss volume of more than 3000 ml, postoperative bowel ischemia and class 3 or 4 according to the Fitzgerald classification were significantly associated with high mortality.

CONCLUSION

These findings showed that every effort to maintain preoperative hemodynamic stability reduce volumes of blood loss in operation, and to minimize postoperative deterioration of organ functions would be essential to improve patient survival.

Effects of thoracic and hiatal clamping in repair of ruptured abdominal aortic aneurysms

The purpose of this study was to determine the effects of hiatal and thoracic clamping on postoperative outcome and morbidity and factors affecting mortality and morbidity. The records of 102 patients who had undergone ruptured abdominal aortic aneurysm repair between 1993 and 2005 were evaluated retrospectively. Hiatal clamping and thoracic clamping were performed in 72 patients and 30 patients, respectively. Postoperative complications and survival were evaluated comparatively between the two groups by univariate and multivariate statistical analyses. Overall mortality and hospital mortality rates were 63 (61.8%) and 24 (23.5%) patients, respectively; and there was no difference between the two groups. Postoperative respiratory complications, gastrointestinal complications, and blood requirement were higher in the thoracic clamping group. Preoperative shock and renal ischemia time (>30 min) were found to be significant predictors of hospital mortality. Postoperative renal failure was the only independent postoperative predictor of mortality. In the follow-up period, cardiac event was an independent predictor of late mortality. If hospital mortalities were excluded, 5-year and 10-year cumulative survivals were 57.82 +/- 5.85% and 38.16 +/- 6.97%, respectively. Cross-clamp level did not have a significant effect on long-term survival. Although both thoracic and hiatal clamping had no effect on mortality, postoperative respiratory complications, blood requirement, and intestinal ischemia were more pronounced in patients operated with thoracic clamping. Hiatal clamping is preferable for a safe postoperative period.

Carotid ultrasound findings as a predictor of long-term survival after abdominal aortic aneurysm repair: a 14-year prospective study

PURPOSE

Several factors have been related to long-term survival after open abdominal aortic aneurysm (AAA) repair. The effect of carotid stenosis on outcome has not yet been examined. We performed an open prospective study to evaluate the prognostic significance of carotid stenosis on long-term survival of patients who had undergone elective operative repair of AAA.

METHODS

Two hundred eight patients who underwent elective open AAA repair in our department between March 1987 and December 2001 were included in the study. All patients were evaluated preoperatively with color duplex ultrasound (US) scanning of the carotid arteries, and were followed up with clinical examination and carotid duplex US scanning 1 month after the operation and every 6 months thereafter. Median duration of follow-up was 50 months (range, 5-181 months). Cardiovascular morbidity and mortality, as well as all causes of mortality, were recorded and analyzed with regard to traditional risk factors and carotid US findings.

RESULTS

Twenty-seven fatal and 46 nonfatal cardiovascular events were recorded. Both univariate and multivariate analysis showed that carotid stenosis 50% or greater and echolucent plaque were significantly associated with cardiovascular mortality and morbidity. Carotid stenosis was a stronger predictor of cardiovascular death than was ankle/brachial index. Age, hypercholesterolemia, coronary artery disease, and diabetes mellitus were also associated with higher mortality and morbidity from cardiovascular causes.

CONCLUSION

Patients electively operated on for AAA repair and with stenosis 50% or greater and echolucent plaque at duplex US scanning are at significantly increased risk for cardiovascular mortality and morbidity. Carotid US can therefore be used to select a subgroup of patients with AAA who might benefit from medical intervention, including antiplatelet and lipid-lowering agents.

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

Background

The mortality rate associated with elective aortic aneurysm repair is widely assumed to be in the region of 5 per cent. This figure does not take into consideration the effect of pre-existing risk factors. The Vascular Anaesthesia Society of Great Britain and Ireland conducted a large audit to estimate the in-hospital mortality rate associated with non-emergency infrarenal aortic surgery throughout the British Isles, and to determine the influence of risk factors on mortality rate.

Methods

This was a multicentre, prospective audit of 177 hospitals throughout the UK and Ireland. Data were collected by questionnaire to include all patients undergoing elective or urgent surgery for infrarenal abdominal aortic aneurysm or aortoiliac occlusive disease over 4 months.

Results

Nine hundred and thirty-three patients were recruited into the audit. The overall mortality rate was 7·3 per cent. Factors increasing the risk of death by up to fivefold included age over 74 years, urgent surgery, operation for occlusive disease, limited exercise capacity, a history of severe angina or cardiac failure, the presence of ventricular ectopics and abnormalities suggesting ischaemic heart disease on electrocardiography.

Conclusion

Although the in-hospital mortality rate was similar to previously published figures, the rate increased considerably when commonly encountered risk factors were present.

Risk stratification and outcomes of transluminal endografting for abdominal aortic aneurysm: 7-year experience and long-term follow-up

PURPOSE

To determine early and late outcomes of transluminal endografting (TE) in patients with abdominal aortic aneurysm (AAA), stratified by predicted risk of procedure-related mortality with conventional operation.

MATERIALS AND METHODS

A retrospective study was conducted in consecutive risk-stratified AAA patients undergoing TE at a not-for-profit cardiovascular referral center from March 1994 through November 2000 with follow-up through February 2001. With use of conventional risk strata (0 = low, 1 = minimal, 2 = moderate, and 3 = high), predicted procedure-related mortalities were 0%-1% in stratum 0 (n = 40), 1%-3% in stratum 1 (n = 118), 3%-8% in stratum 2 (n = 116), and 8%-30% in stratum 3 (n = 31). Main outcome measures were: (i) TE procedural success, (ii) procedure-related mortality, (iii) major nonfatal complications, (iv) composite adverse outcome (ii + iii), (v) length of stay (LOS), (vi) freedom from AAA rupture, (vii) late survival, (viii) late complications, and (ix) endoleaks and their classification and management.

RESULTS

Women were significantly less likely than men to qualify for and undergo endografting: 24 of 91 (26.4%) women underwent TE, compared to 281 of 684 (41.1%) men. Of 305 attempted TE procedures, 291 (95.4%) were successful, four (1.3%) were urgently converted to open repair, and 10 (3.3%) were aborted. Procedure-related mortalities occurred in eight cases (2.6%) overall and one of 40 (2.5%), one of 118 (0.8%), four of 116 (3.4%), and two of 31 (6.5%) cases for risk strata 0-3, respectively. Perioperative survivors were significantly younger than nonsurvivors (74.3 y +/- 9 vs 81.6 y +/- 5.1; P =.0087). Forty-six patients (15.1%) had major complications. Composite adverse outcome was worse for patients in stratum 3 than those in stratum 1 (P =.0296) and those in strata 0, 1, and 2 combined (P =.026). Procedure-related mortality declined with institutional experience, from 4% among the first 100 patients undergoing TE to 1% among the last 105. For strata 0-3, median LOS were 2, 3, 3, and 4 days, respectively. Seventy patients (22.9%) had 75 endoleaks, of which 30 necessitated additional procedures, 17 self-resolved, and 22 were untreated as of March 1, 2001. Five patients with endoleak died of unrelated causes. One late-onset type IA endoleak (26 mo) resulted in the only AAA rupture and death in the follow-up period among the 291 patients who underwent successful transluminal endograft implantation. Actuarial survival rates at 1 year after TE were 90.3% +/- 1.9% for the overall study group and 97.5% +/- 2.5%, 94% +/- 2.5%, 86.9% +/- 3.3%, and 81.3% +/- 7.7% for risk strata 0-3, respectively. At 5 years, overall actuarial survival was 69.6% +/- 6.1%. Thirty-eight late deaths were attributable to post-TE AAA rupture (n = 1), AAA rupture late after failed TE with no further treatment (n = 1), other cardiovascular disorders (n = 7), cancer (n = 15), other causes (n = 10), and unknown causes (n = 4). Late deaths occurred in risk strata 0-3 at the following rates: two of 40 (5%), 10 of 118 (8.5%), 16 of 116 (13.8%), and 10 of 31 (32.3%), respectively (stratum 0 vs stratum 3, P =.0017; stratum 1 vs stratum 3, P =.003).

CONCLUSIONS

TE is safe and confers durable protection against AAA rupture in treated populations. Still, protection is not absolute in patients with endoleaks, because late AAA enlargement and even rupture can occur. Given current knowledge, technology, and practice, careful patient selection and close surveillance of patients after implantation of transluminal endografts is essential.

Aneurysm rupture is independently associated with increased late mortality in those surviving abdominal aortic aneurysm repair

PURPOSE

The aim of this study was to define whether veterans who survived repair of ruptured abdominal aortic aneurysms (AAA) experienced late survival rates similar to those surviving repair of intact AAA.

METHODS

All veterans undergoing AAA repair in DRGs 110 and 111 during fiscal years 1991-1995 were identified using the Veterans Affairs (VA) Patient Treatment File (PTF). Late mortality was defined using VA administrative databases including the Beneficiary Identification and Record Locator System and PTF. Illness severity and patient complexity were defined using PTF discharge data that were further analyzed by Patient Management Category software. Veterans were followed up to 6 years after AAA repair.

RESULTS

During the study, 5833 veterans underwent repair of intact AAA while 427 had repair of ruptured AAA in all VA medical centers. Operative mortality was defined as that which occurred within 30 days of surgery or during the same hospitalization as aneurysm repair. For those undergoing repair of intact AAA, operative mortality thus defined was 4.5% (265/5833). Operative mortality was 46% (195/427) after repair of ruptured AAA. Overall mortality (including operative mortality) during 2.62+/-1.61 years follow-up was 22% (1282/5833) with intact AAA versus 61% (260/427) for those with ruptured AAA (P<0.001). Further analysis of survival outcomes was performed in patients who survived AAA repair (i.e., those who were discharged alive and lived 30 days or more after surgery). Of those who initially survived repair of ruptured AAA, 28% (65/232) died during follow-up versus 18% (1017/5568) who initially survived repair of intact AAA (odds ratio 1.74; 95% confidence limits 1.30-2.34; P<0.001). In those initially surviving AAA repair, stepwise logistic regression analysis revealed that increasing age, illness severity, patient complexity, as well as AAA rupture and aortic graft complications were increasingly and independently associated with late mortality. Mean survival time was 1681 days for those who survived >30 days and who were discharged alive after repair of ruptured AAA versus 1821 days for those who initially survived repair of intact AAA (P< 0.001).

CONCLUSIONS

In addition to higher postoperative mortality rates with ruptured AAA, mortality during follow-up for survivors of AAA repair was also greater for those who survived repair of ruptured AAA. The toll taken by ruptured abdominal aortic aneurysms did not end in the immediate postoperative period.