Early and late outcome of surgical repair for small abdominal aortic aneurysms: A population-based analysis

Excess Mortality for Abdominal Aortic Aneurysms and the Potential of Strict Implementation of Cardiovascular Risk Management: A Multifaceted Study Integrating Meta-Analysis, National Registry, and PHAST and TEDY Trial Data

OBJECTIVE

Previous studies imply a profound residual mortality risk following successful abdominal aorta aneurysm (AAA) repair. This excess mortality is generally attributed to increased cardiovascular risk. The aim of this study was (1) to quantify the excess residual mortality for patients with AAA, (2) to evaluate the cross sectional level of cardiovascular risk management, and (3) to estimate the potential of optimised cardiovascular risk management to reduce the excess mortality in these patients.

METHODS

Excess mortality was estimated through a systematic review and meta-analysis, and through data from the Swedish National Health Registry. Cardiovascular risk profiles were individually assessed during eligibility screening of patients with AAA for two multicentre pharmaceutical AAA stabilisation trials. The potential of full implementation of cardiovascular risk management was estimated through the validated Second Manifestations of ARTerial disease (SMART) risk scores algorithm.

RESULTS

The meta-analysis showed a similarly impaired survival for patients who received early repair (small AAA) or regular repair (≥ 55 mm), and a further impaired survival for patients under surveillance for a small AAA. Excess mortality was further quantified using Swedish population data. The data revealed a more than quadrupled and doubled five year mortality rate for women and men who had their AAA repaired, respectively. Evaluation of the level of risk management of 358 patients under surveillance in 16 Dutch hospitals showed that the majority of patients with AAA did not meet therapeutic targets set for risk management in high risk populations, and indicated a more pronounced prevention gap in women. Application of the SMART risk score algorithm predicted that optimal implementation of risk management guidelines would reduce the 10 year risk of major adverse cardiovascular events from 43% to 14%.

CONCLUSION

Independent of the rupture risk, AAA is associated with a worryingly compromised life expectancy with a particularly poor prognosis for women. Optimal implementation of cardiovascular risk prevention guidelines is predicted to profoundly reduce cardiovascular risk.

Editor's Choice - Endovascular Aneurysm Repair in High Risk Patients: A Systematic Review and Meta-Analysis

OBJECTIVE

To investigate outcomes of endovascular aneurysm repair (EVAR) in high risk patients.

METHODS

Bibliographic sources (MEDLINE, EMBASE, CINAHL, and CENTRAL) were searched using combinations of thesaurus and free text terms. The review protocol was registered in PROSPERO (CRD42021287207) and reported according to PRISMA 2020. Pooled estimates were calculated using odds ratio (OR) or hazard ratio (HR) and 95% confidence interval (CI) applying the Mantel-Haenszel or inverse variance method. EVAR peri-operative mortality in high risk patients over time was examined with mixed effects meta-regression. The GRADE framework was used to rate the certainty of evidence.

RESULTS

The pooled peri-operative mortality in 18 416 high risk patients who underwent EVAR was 3% (95% CI 2.3 - 4%) and has significantly reduced over time (year of publication p = .003; median study point p = .023). The peri-operative mortality was significantly lower in high risk patients treated with EVAR compared with open repair (OR 0.64; 95% CI 0.45 - 0.92), but no significant difference was found in overall (HR 1.06; 95% CI 0.76 - 1.49) or aneurysm related mortality (HR 0.57; 95% CI 0.21 - 1.55). No significant difference was found in overall mortality between high risk patients treated with EVAR vs. no intervention (HR 0.42; 95% CI 0.14 - 1.26), but the aneurysm related mortality was significantly lower in the former (HR 0.30; 95% CI 0.14 - 0.63). The peri-operative mortality was higher in high risk than normal risk patients treated with EVAR (OR 2.33; 95% CI 1.75 - 3.10), as was the overall mortality (HR 3.50; 95% CI 2.55 - 4.80). The certainty of evidence was very low for EVAR vs. open surgery or no intervention and low for high vs. normal risk patients.

CONCLUSION

The EVAR peri-operative mortality in high risk patients has improved over time. Even though the aneurysm related mortality of EVAR is lower compared with no intervention, EVAR may confer no overall survival benefit.

Malnutrition provides important long-term prognostic information in patients undergoing endovascular abdominal aortic aneurysm repair

OBJECTIVES

Malnutrition has been shown to be associated with survival in a variety of diseases. Our aim is to evaluate the prognostic value of objective nutritional indexes indicating malnutrition, in patients underwent endovascular aortic replacement.

METHODS

We retrospectively evaluated 149 consecutive patients who underwent technically successful endovascular aortic replacement operation between October 2010 and August 2019. Objective nutritional indexes, prognostic nutritional index, geriatric nutritional risk index and controlling nutritional status, scores were calculated using the preoperative data. Optimal cut-off values were obtained by receiver operating characteristic analysis. According to the cut-off values, we investigated the relationship between indexes and the long-term all-cause mortality.

RESULTS

During mean 48.0 ± 30.3 months follow-up duration, in 47 of patients (31.5%), all-cause mortality were documented. In mortality group, prognostic nutritional index (42.8 ± 7.1 vs 51.3 ± 5.2, p < 0.001) and geriatric nutritional risk index (100.7 ± 10.1 vs 107.6 ± 9.2, p < 0.001) were significantly lower, controlling nutritional status score (2.0 (1.0-4.0) vs 1.0 (0.0-2.0), p < 0.001) was higher when compared to survivor group. Kaplan-Meier curves presented higher mortality incidence in malnutrition patients evaluated with objective nutritional indexes (Log-rang test, for all three indexes p < 0.001). Besides Cox-proportional hazard analysis showed all three nutritional indexes may be a predictive marker for all-cause mortality, prognostic nutritional index introduced more valuable data than other two indexes.

CONCLUSIONS

Malnutrition is associated with significant increase in postoperative long-term mortality in endovascular aortic replacement patients. Preoperatively calculated objective nutritional indexes especially prognostic nutritional index can be used as an important prognostic tool.

Endovascular Aortic Aneurysm Repair with the Zenith AAA Endovascular Graft: Does Gender Affect Procedural Success, Postoperative Morbidity, or Early Survival?

The purpose of this study was to analyze the effect of gender on deployment, early morbidity, and survival after endovascular aortic aneurysm repair (EVAR) using the Zenith Endovascular Graft. Data were obtained from the U.S. Multicenter Zenith Endograft trial and complemented with results from the Zenith female registry, including 40 women (10.9%) and 326 men (89.1%). Data analysis included preoperative medical risk factors, aneurysm morphology, deployment, and postoperative morbidity data, and 30-day and 1-year results. Preoperatively, women more often had experienced thromboembolic events (13% vs 4.3%; P = 0.04), but less angina pectoris (24% vs 49%; P = 0.002) or myocardial infarction (18% vs 38%; P = 0.01) compared with men. Women had more angulated aneurysm necks and narrower iliac arteries compared with men. Procedural success, cardiovascular, pulmonary, renal, bowel-related, neurologic, or other adverse events were comparable, as were 30-day and 1-year survival. Females experienced more wound dehiscences (5.0% vs 0.0%; P = 0.01) and open surgical conversions in the first year (5%) compared with men (0.31%) ( P = 0.03). With more challenging aneurysm morphologies, women were found to be at a higher risk for conversion in the first year after EVAR using the Zenith endograft. This however does not translate into inferior survival or higher overall morbidity compared with men.

Cost-effectiveness of contrast-enhanced ultrasound for the detection of endovascular aneurysm repair-related endoleaks requiring treatment

OBJECTIVE

Follow-up after endovascular aneurysm repair is necessary to detect potentially life-threatening complications such as endoleaks. Computed tomography angiography (CTA) or magnetic resonance angiography (MRA) is often used as standard of care for follow-up. Contrast-enhanced ultrasound (CEUS) has been shown to be a viable and fast real-time nonionizing imaging modality with equivalent diagnostic accuracy while also being superior to color Doppler ultrasound. The aim of this cost-utility analysis was to evaluate the cost-effectiveness of this imaging method in comparison to others for the evaluation of endoleaks requiring treatment.

METHODS

A decision model based on Markov simulations estimated lifetime costs and quality-adjusted life years (QALYs) associated with CTA, MRA, CEUS, and color Doppler ultrasound. Model input parameters were obtained from recent literature. The applied sensitivity and specificity values amounted to 90.5% and 100.0% for CTA, 96.0% and 100.0% for MRA, 94.0% and 95.0% for CEUS, and 82.0% and 93.0% for color Doppler ultrasound. Probabilistic and deterministic sensitivity analysis was performed to estimate uncertainty of model results. To evaluate cost-effectiveness, incremental cost-effectiveness ratios were reported as a measure representing the economic value of a strategy compared with an alternative. The willingness to pay was set to $100,000/QALY.

RESULTS

In the base-case scenario for a willingness to pay of $100,000 per QALY, CEUS was the most cost-effective of the four diagnostic strategies with estimated costs of $17,383 and effectiveness of 9.770 QALYs. CTA was estimated to result in lifetime costs of $17,679 with an expected effectiveness of 9.768 QALYs, whereas color Doppler ultrasound showed expected costs of $17,287 with 9.763 QALYs. Expected costs and effectiveness of MRA amounted to $17,945 and 9.771 QALYs each. Base-case estimates of the incremental cost-effectiveness ratios for CEUS vs color Doppler ultrasound equaled $14,173.52/QALY.

CONCLUSIONS

CEUS is a cost-effective imaging method for the evaluation of therapy-requiring endoleaks in endovascular aneurysm repair surveillance.

Prospective Ultrasound Screening of Men With Cerebrovascular Disease for Abdominal Aortic Aneurysms

BACKGROUND

The prevalence of abdominal aortic aneurysms is higher in population with other vascular comorbidities, especially among men. Utility of screening among patients with cerebrovascular disease is unclear.

OBJECTIVE

To determine the prevalence of abdominal aortic aneurysm in male patients with diagnosed cerebrovascular disease manifested by transient ischemic attack or stroke.

METHODS

Between May 2013 and May 2014, all consecutive male patients undergoing carotid ultrasound in single tertiary center with a catchment area of 179,000 inhabitants were evaluated for ultrasound screening of abdominal aortic aneurysm. Abdominal aortic aneurysm was defined as maximum diameter of infrarenal aorta 30 mm or more.

RESULTS

Of 105 (n = 105) consecutively evaluated male patients, only 69% (n = 72) were eligible for the study and underwent aortic screening. Reason for ineligibility was most often poor general medical condition (n = 29). Mean age of screened patients was 66 years (SD 9.8 years). Half of the screened patients suffered stroke (n = 36). The incidence of abdominal aortic aneurysm was 5.6% (n = 4). All found abdominal aortic aneurysms were small and did not require immediate surgical intervention. During a follow-up period of over 4 years, none of the aneurysms exhibited tendency for growth.

CONCLUSIONS

The male population with cerebrovascular disease is comorbid and frail. Only, moderate prevalence of abdominal aortic aneurysms can be found in this subpopulation.

Analysis of Echocardiographic Markers and Pulse Wave Velocities in a Patient Who Developed New Cardiac Symptoms after Implantation of an Aortic Endograft

Increased arterial stiffness has been related to altered cardiovascular hemodynamics, left ventricular hypertrophy, and a higher risk for cardiac events. Pulse wave velocity (PWV) has been used as a surrogate marker for arterial stiffness. Treatment of abdominal aortic aneurysms (AAAs) involves insertion of a rigid graft or endograft inside the arterial system which has been shown to increase arterial stiffness, but the cardiac implications of these alterations are mostly unknown. We report a case of a patient with a previous AAA surgical repair (>10 years ago) who developed a para-anastomotic pseudoaneurysm which was excluded with implantation of an endoluminal graft. From a cardiac perspective, this patient was asymptomatic and had a normal baseline preoperative evaluation. He had an initially high PWV (17 m/sec). Postprocedurally, the patient developed cardiac symptoms, and he underwent coronary angiography which indicated significant coronary artery disease, and he subsequently underwent bypass grafting. One week after the endovascular repair, the patient presented with an increased PWV at 21 m/sec. Echocardiographic indices were mostly unaltered (ejection fraction, left ventricular mass index, and left atrium volume index) compared with the preoperative evaluation, except for the global longitudinal strain which deteriorated from -25 to -21%. This case provides insight into hemodynamic alterations after implantation of an endograft which may result in deterioration of asymptomatic heart disease.

Operative Repair for Aortic Aneurysms: The Gold Standard

Surgical treatment of abdominal aortic aneurysm (AAA) is being challenged by newer, minimally invasive therapies. Such new treatment strategies will need to prove themselves against concurrent results of standard operative AAA repair, within defined medical risk and aneurysm morphological categories. We review the natural history of AAAs, the medical risk levels for elective AAA repair, aneurysm morphology and its impact on operative mortality, the issue of high-risk patient treatment, and the current standard of care for AAAs based on single-center, multicenter, and population-based statistics. In good-risk patients, aneurysms > 5 cm in diameter are best treated by replacement with a prosthetic graft. Operative mortality should be < 5% and 1-year survival > 90%. Aortic endograft techniques must meet or exceed these standards if they are to supplant standard surgical repair.

Transthoracic Echocardiography Provides Important Long-Term Prognostic Information in Selected Patients Undergoing Endovascular Abdominal Aortic Repair

BACKGROUND

The value of performing transthoracic echocardiography (TTE) as part of the clinical assessment of patients awaiting endovascular repair of the abdominal aorta is little evaluated. We aimed to estimate the prognostic importance of information derived from TTE on long-term all-cause mortality in a selected group of patients undergoing endovascular aneurysm repair.

METHODS AND RESULTS

This was a retrospective cohort study of 273 consecutive patients selected for endovascular aneurysm repair. All patients included in the analysis underwent TTE before their procedure. Multivariable Cox regression analysis was used to estimate the effect of TTE measures on all-cause mortality. Over a mean follow-up of 3.2±1.5 years, there were 78 deaths with a mean time to death of 1.28±1.16 years. A greater tubular ascending aorta (hazard ratio [HR] 5.6, 95% confidence interval [CI] 2.77-11.33), presence of mitral regurgitation (HR 8.13, 95% CI 4.09-12.16), lower left ventricular ejection fraction (HR 0.96, 95% CI 0.93-0.98), younger age (HR 0.97, 95% CI 0.95-0.99), and presence of diabetes mellitus (HR 1.46, 95% CI 1.24-1.89) were predictors of all-cause mortality.

CONCLUSIONS

Echocardiography provides important long-term prognostic information in patients undergoing endovascular aneurysm repair. These TTE indices were more important at predicting outcome than standard conventional risk factors in this patient group. A greater tubular ascending aorta, presence of mitral regurgitation, reduced left ventricular ejection fraction, younger age, and diabetes mellitus were independently associated with long-term mortality.

Systematic Review and Meta-analysis of Long-term survival After Elective Infrarenal Abdominal Aortic Aneurysm Repair 1969-2011: 5 Year Survival Remains Poor Despite Advances in Medical Care and Treatment Strategies

Background

Improved critical care, pre-operative optimization, and the advent of endovascular surgery (EVAR) have improved 30 day mortality for elective abdominal aortic aneurysm (AAA) repair. It remains unknown whether this has translated into improvements in long-term survival, particularly because these factors have also encouraged the treatment of older patients with greater comorbidity. The aim of this study was to quantify how 5 year survival after elective AAA repair has changed over time.

Methods

A systematic review was performed identifying studies reporting 5 year survival after elective infrarenal AAA repair. An electronic search of the Embase and Medline databases was conducted to January 2014. Thirty-six studies, 60 study arms, and 107,814 patients were identified. Meta-analyses were conducted to determine 5 year survival and to report whether 5 year survival changed over time.

Results

Five-year survival was 69% (95% CI 67 to 71%, I² = 87%). Meta-regression on study midpoint showed no improvement in 5 year survival over the period 1969–2011 (log OR −0.001, 95% CI −0.014–0.012). Larger average aneurysm diameter was associated with poorer 5 year survival (adjusted log OR −0.058, 95% CI −0.095 to −0.021, I² = 85%). Older average patient age at surgery was associated with poorer 5 year survival (adjusted log OR −0.118, 95% CI −0.142 to −0.094, I² = 70%). After adjusting for average patient age, an improvement in 5 year survival over the period that these data spanned was obtained (adjusted log OR 0.027, 95% CI 0.012 to 0.042).

Conclusion

Five-year survival remains poor after elective AAA repair despite advances in short-term outcomes and is associated with AAA diameter and patient age at the time of surgery. Age-adjusted survival appears to have improved; however, this cohort as a whole continues to have poor long-term survival. Research in this field should attempt to improve the life expectancy of patients with repaired AAA and to optimise patient selection.

Systematic review of cardiovascular disease and cardiovascular death in patients with a small abdominal aortic aneurysm

Background

Screening for abdominal aortic aneurysm (AAA) has reduced the rate of AAA rupture. However, cardiovascular disease is still a major cause of death in men with an AAA. The aim of this study was to assess cardiovascular risk in patients with a small AAA.

Methods

Standard PRISMA guidelines were followed. Analysis was performed of studies reporting cardiovascular outcomes in patients with a small AAA (30–54 mm). Weighted metaregression was performed for cardiovascular death in patients with a small AAA, and the prevalence of cardiovascular disease was reviewed.

Results

Twenty-one articles were identified describing patients with an AAA, and the prevalence of, and death from, cardiovascular disease. Ten of these reported cardiovascular death rates in patients with a small AAA. Some 2323 patients with a small AAA were identified; 335 cardiovascular deaths occurred, of which 37 were due to AAA rupture. Metaregression demonstrated that the risk of cardiovascular death was 3·0 (95 per cent c.i. 1·7 to 4·3) per cent per year in patients with a small AAA (R2 = 0·902, P &lt; 0·001). The prevalence of ischaemic heart disease (44·9 per cent), myocardial infarction (26·8 per cent), heart failure (4·4 per cent) and stroke (14·0 per cent) was also high in these patients.

Conclusion

The risk of cardiovascular death in patients with a small AAA is high and increases by approximately 3 per cent each year after diagnosis. Patients with a small AAA have a high prevalence of cardiovascular disease. Patients a small AAA should be considered for lifestyle modifications and secondary cardiovascular protection.

Circulating interleukin-6 levels are associated with abdominal aortic aneurysm presence: a meta-analysis and meta-regression of case-control studies

BACKGROUND

In a number of relatively small-size studies, investigators have measured and compared circulating interleukin-6 (IL-6) levels in cases with abdominal aortic aneurysm (AAA) and controls without AAA to assess its possible role in the pathogenesis or progression of AAA. To summarize the present evidence for an association between circulating IL-6 levels and AAA presence, we performed a meta-analysis of case-control studies that compared circulating IL-6 levels between patients with AAA and subjects without AAA.

METHODS

MEDLINE and EMBASE were searched through December 2013 using Web-based search engines (PubMed and OVID). Eligible studies were case-control studies of patients with AAA and subjects without AAA reporting circulating IL-6 levels. For each study, data regarding plasma or serum IL-6 levels in both the AAA and control groups were used to generate standardized mean differences (SMDs) and 95% confidence intervals (CIs). Mixed-effects (unrestricted maximum likelihood) meta-regression analyses were performed to determine whether the differences in circulating IL-6 levels were modulated by the prespecified factors.

RESULTS

Our search identified 13 eligible studies enrolling a total of 1,029 cases with AAA and 924 controls without AAA. Pooled analysis of the 13 studies demonstrated significantly greater circulating IL-6 levels in the AAA group than those in the control group (random-effects SMD 0.59; 95% CI 0.37-0.80; P for effect < 0.00001; P for heterogeneity < 0.0000). The meta-regression coefficient for the mean age (P = 0.10196) and the proportion of current smokers (P = 0.29893) was not statistically significant. That for the mean AAA diameter, however, was significantly positive (coefficient 0.02789; 95% CI 0.00778-0.04800; P = 0.00657), and that for the proportion of men was significantly negative (coefficient -0.01823; 95% CI -0.03202 to -0.00445; P = 0.00952).

CONCLUSIONS

Circulating IL-6 levels are greater in patients with AAA than those in subjects without AAA, which suggest that greater circulating IL-6 levels are associated with AAA presence. As the mean AAA diameter and the proportion of men increase, circulating IL-6 levels in patients with AAA are respectively more and less greater than those in controls without AAA.

Abdominal aortic aneurysm: Treatment options, image visualizations and follow-up procedures

Abdominal aortic aneurysm is a common vascular disease that affects elderly population. Open surgical repair is regarded as the gold standard technique for treatment of abdominal aortic aneurysm, however, endovascular aneurysm repair has rapidly expanded since its first introduction in 1990s. As a less invasive technique, endovascular aneurysm repair has been confirmed to be an effective alternative to open surgical repair, especially in patients with co-morbid conditions. Computed tomography (CT) angiography is currently the preferred imaging modality for both preoperative planning and post-operative follow-up. 2D CT images are complemented by a number of 3D reconstructions which enhance the diagnostic applications of CT angiography in both planning and follow-up of endovascular repair. CT has the disadvantage of high cummulative radiation dose, of particular concern in younger patients, since patients require regular imaging follow-ups after endovascular repair, thus, exposing patients to repeated radiation exposure for life. There is a trend to change from CT to ultrasound surveillance of endovascular aneurysm repair. Medical image visualizations demonstrate excellent morphological assessment of aneurysm and stent-grafts, but fail to provide hemodynamic changes caused by the complex stent-graft device that is implanted into the aorta. This article reviews the treatment options of abdominal aortic aneurysm, various image visualization tools, and follow-up procedures with use of different modalities including both imaging and computational fluid dynamics methods. Future directions to improve treatment outcomes in the follow-up of endovascular aneurysm repair are outlined.

Long-term surveillance with computed tomography after endovascular aneurysm repair may not be justified

Background

There is a common perception that a large number of secondary interventions are needed following endovascular aortic aneurysm repair.

Methods

Prospective data were collected for a cohort of 417 consecutive elective patients undergoing infrarenal aortic endograft repair between April 2000 and May 2008. The rate of secondary interventions, associated morbidity and need for reintervention following surveillance imaging were analysed.

Results

The male : female ratio was 11 : 1, median age 76 (range 40–93) years and median aneurysm diameter 6·1 (5·3–11) cm. The overall 30-day mortality rate was 1·7 per cent (seven of 417). Secondary interventions were performed in 31 patients (7·4 per cent), of which six (1·4 per cent) were detected by surveillance. Endoleaks requiring reintervention occurred in 12 patients (2·9 per cent; ten type I and two type III endoleaks). Limb ischaemia secondary to graft occlusion occurred in 17 patients (4·1 per cent); extra-anatomical bypass was needed in 15 patients (3·6 per cent) and the remaining two had an amputation. Graft explantation following late infection was required in two patients (0·5 per cent).

Conclusion

Endoluminal repair of infrarenal aortic aneurysms can be performed with a low reintervention rate. The value of prolonged surveillance seems limited and current surveillance protocols may require revision.

Aortic aneurysms secrete interleukin-6 into the circulation

OBJECTIVE

Circulating plasma interleukin-6 (IL-6) concentrations are elevated in patients with abdominal aortic aneurysms (AAAs) compared with controls. In vitro studies suggest that the aneurysm is the source of the IL-6. Because IL-6 is an independent risk factor for cardiovascular mortality, elevation of this cytokine may be significant in these patients, who represent a group at increased risk from cardiovascular death. The aim of this study was to directly measure in vivo aortic IL-6 concentrations, testing the hypothesis that aneurysms secrete IL-6 into the circulation.

METHODS

Before endovascular aneurysm repair took place, blood was sampled from the entire length of the aorta in 27 patients with AAA and nine with thoracic aneurysms (TAs). A control group consisted of 15 patients without aneurysms undergoing angiography. Plasma IL-6 was determined using enzyme-linked immunosorbent assay, and high-sensitivity C-reactive protein (hs-CRP) was measured turbidimetrically. Aneurysm surface area was calculated from axial computed tomography scans.

RESULTS

Mean IL-6 concentrations (pg/mL) were higher in the TA and AAA groups compared with controls (10.4 +/- 3.7 and 4.9 +/- 0.5 vs 2.7 +/- 0.5, P = .002). There was a significant difference in plasma IL-6 concentration corresponding to aneurysm position in the AAA (P = .002) and TA (P = .008) groups, with both patterns conforming to a linear trend. This pattern was not observed in the control group, in which no significant difference in IL-6 concentrations was found throughout the aorta. Peak IL-6 occurred earlier in TAs compared with AAAs (descending aorta vs iliac artery) corresponding to aneurysm position (P = .0007). Linear regression revealed a positive correlation between aneurysm surface area and mean plasma IL-6 (Spearman's correlation, P = .003). The mean surface areas of the TAs, at 0.07 m2 (interquartile range [IQR], 0.06 to 0.09), were higher than those of the AAAs at 0.03 m2 (IQR, 0.02 to 0.04; P = .002). High-sensitivity CRP was within normal limits, and no significant differences were found between the AAA group and the controls.

CONCLUSIONS

Circulating IL-6 is elevated within the aorta in patients with aneurysms and corresponds to aneurysm position. Furthermore, aneurysm surface area and mean plasma IL-6 are correlated. In the absence of any evidence of systemic inflammation in the form of elevated hs-CRP, these data support the hypothesis that aneurysms secrete IL-6 into the circulation. This may contribute to the high cardiovascular mortality observed in patients with aneurysms.

Thoracoabdominal Aneurysm Repair: A 20-Year Perspective

BACKGROUND

A variety of operative approaches and protective adjuncts have been used to minimize organ dysfunction and, in particular, spinal cord injury (SCI) after thoracoabdominal aneurysm (TAA) repair. There is no consensus with respect to the optimal approach.

METHODS

Reviewed were 445 consecutive TAA repairs done between January 1987 and December 2005. Clinical features included urgent operation in 103 patients (22.6%), of which 52 (11.4%) were ruptures. Operative management consisted of a clamp-and-sew technique with adjuncts in 417 patients (92%). Epidural cooling to prevent SCI was used in 240 (68%) extent I to III repairs. Predictors of mortality and SCI were assessed with multivariate analysis, and long-term survival was determined with Kaplan-Meier life-table analysis.

RESULTS

Operative mortality was 8.2% and was associated with preoperative serum creatinine level of 1.8 mg/dL or more (p = 0.005), intraoperative hypotension (p = 0.01), intraoperative transfusion requirement (p = 0.0008), postoperative SCI (p = 0.02), and postoperative renal failure (p < 0.0001). SCI of any severity occurred in 60 patients (13.2%), and 43 (9.5% of the total cohort) sustained major paraplegia. Epidural cooling significantly reduced the risk of SCI in patients with types I to III TAA (13.7% versus 29%, p = 0.01). Independent predictors of SCI included extent I/II aneurysms (p = 0.02), epidural cooling (p = 0.02), urgent/emergent operation (p = 0.02), intraoperative hypotension (p = 0.005), total aortic cross-clamp time (p = 0.01), and postoperative pulmonary complications (p = 0.003). Late survival rates were at 54.4% at 5 years, 28.7% at 10 years, and 20.5% at 15 years.

CONCLUSIONS

Despite the favorable impact of operative adjuncts on perioperative mortality and SCI, major morbidity after TAA remains a challenge; the implications to further develop stent graft strategies are clear.

Long-term survival and temporal trends in patient and surgeon factors after elective and ruptured abdominal aortic aneurysm surgery

OBJECTIVE

Records for all patients in Ontario who underwent elective repair of abdominal aortic aneurysms (AAAs) or repair of ruptured AAAs between 1993 and 1999 were studied to determine whether the profile of surgeons or patients changed and to determine whether postoperative mortality changed over time. The secondary objective was to describe long-term survival after AAA surgery.

METHODS

A population-based retrospective cohort was assembled from administrative data. Surgeon billing records were used to identify operations performed between 1993 and 1999. Chi(2) and linear regression analyses were used to determine whether variables changed over time. Kaplan-Meier survival curves were used to estimate long-term survival.

RESULTS

For patients undergoing elective AAA repair, average annual surgeon volume (P <.0001) and proportion of patients operated on by vascular surgeons (P =.02) increased over the study period; similar trends were noted for patients undergoing repair of ruptured AAAs. Surgeon volume was clearly correlated with mortality after both elective AAA repair and repair of ruptured AAAs; however, the benefit of this effect was modest beyond a surgeon volume of 6 to 10 ruptured AAA repairs per year or 20 to 30 elective AAA repairs per year. No change in crude 30-day mortality (4.5% for elective AAA repair and 40.4% for repair of ruptured AAAs) was noted during the study.

CONCLUSION

Despite the finding that surgery to repair ruptured AAAs and elective repair of AAAs is being increasingly performed by high-volume vascular surgeons, there was no change in early mortality between 1993 and 1999. This may have been because average surgeon volume was already relatively high at the beginning of the study period, which translated into only modest benefit to further increases in surgeon volume.

CT of acute abdominal aortic disorders

Aortic aneurysm rupture, aortic dissection, PAU, acute aortic occlusion, traumatic aortic injury, and aortic fistula represent acute abdominal aortic conditions. Because of its speed and proximity to the emergency department, helical CT is the imaging test of choice for these conditions. MR imaging also plays an important role in the imaging of aortic dissection and PAU, particularly when the patient is unable to receive intravenous contrast material. In this era of MDCT, conventional angiography is used as a secondary diagnostic tool to clarify equivocal findings on cross-sectional imaging. Ultrasound is helpful when CT is not readily available and the patient is unable or too unstable to undergo MR imaging.

Association between long-term statin use and mortality after successful abdominal aortic aneurysm surgery

PURPOSE

To assess the potential long-term beneficial effects of statin use after successful abdominal aortic surgery.

METHODS

Between 1991 and 2001, 570 patients underwent abdominal aortic aneurysm repair at the Erasmus Medical Center. Of the 519 patients (91%) who survived surgery beyond 30 days, 510 (98%) were followed for a median of 4.7 years (interquartile range, 2.7 to 7.3 years). These patients were evaluated for use of statins and beta-blockers, and for clinical risk factors (e.g., advanced age; prior myocardial infarction; diabetes mellitus; renal dysfunction; chronic pulmonary disease; history of heart failure, stroke, or angina), and their association with all-cause and cardiovascular mortality.

RESULTS

A total of 205 patients (40%) died during follow-up; 140 due to cardiovascular causes. The incidence of all-cause (18% [27/154] vs. 50% [178/356], P <0.001) and cardiovascular (11% [17/154] vs. 34% [122/356], P <0.001) mortality was significantly lower in statin users than in nonstatin users. After adjusting for clinical risk factors and beta-blocker use, the association between statin use and reduced all-cause (hazard ratio [HR] = 0.4; 95% confidence interval [CI]: 0.3 to 0.6; P <0.001) and cardiovascular (HR = 0.3; 95% CI: 0.2 to 0.6; P <0.001) mortality persisted. Beta-blocker use was also associated with a significant reduction in all-cause (HR = 0.6; 95% CI: 0.5 to 0.9; P = 0.003) and cardiovascular (HR = 0.7; 95% CI: 0.4 to 0.9; P = 0.03) mortality. There was no evidence of an association between statin use and all-cause and cardiovascular mortality according to beta-blocker use or clinical risk factors.

CONCLUSION

Long-term statin use is associated with reduced all-cause and cardiovascular mortality irrespective of clinical risk factors and beta-blocker use.

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.

Anaesthesia and endovascular surgery

Anaesthetic requirements for endovascular surgery for aortic, carotid and peripheral vascular disease are reviewed. Peculiarities of the surgery which may impinge on anaesthetic management are discussed together with the pre-operative assessment issues of particular relevance to patients with generalized vascular disease. The detailed anaesthetic management for carotid and aortic endovascular repair is addressed. The lowered peri-operative stress and general morbidity levels which occur with endovascular surgery allow sicker patients with greater risk factors to present for this type of surgery, thus increasing the challenges facing anaesthetists.

Durability of open repair of infrarenal abdominal aortic aneurysm: a 15-year follow-up study

PURPOSE

This study reviewed the long-term outcome of patients who underwent open repair of infrarenal abdominal aortic aneurysms (AAAs).

METHODS

A retrospective study of 208 patients (188 men and 20 women) with a mean age of 65.6 years who survived elective or emergency open repair of an infrarenal AAA was conducted at a university referral hospital. Main outcome measures included late graft-related complications, survival free from any reintervention, survival free from any vascular reintervention, and overall survival rates.

RESULTS

Late graft-related complications occurred in 32 patients (15.4%). A proximal para-anastomotic pseudoaneurysm developed in six patients (2.9%), and a distal pseudoaneurysm developed in 18 patients (8.7%); in seven of these cases (3.4%), it was bilateral or recurrent. A graft limb occlusion occurred in 11 patients (5.3%). These complications required 37 surgical or other invasive procedures in 27 patients (13.0%). Thirty-one vascular and/or endovascular reoperations were performed. The 5-year, 10-year, and 15-year survival free from any reintervention rates were 91.5%, 86.2%, and 72.0%, respectively. At the same intervals, the survival free from any vascular reintervention rates were 93.8%, 88.5%, and 73.9%, respectively, and the overall survival rates were 66.8%, 39.4%, and 18.0%, respectively. Complications associated with a ruptured femoral artery pseudoaneurysm, a ruptured aortic pseudoaneurysm, an aortoduodenal fistula, and the elective repair of a femoral pseudoaneurysm were the graft-related causes of death, which occurred in four patients (1.9%). Age (P <.0001) and chronic obstructive pulmonary disease (P =.002) were shown by means of multivariate analysis to be predictive of poor survival outcome, and chronic obstructive pulmonary disease (P =.02) and lower limb ischemia (P =.04) were shown to be associated with an increased need for vascular reinterventions to treat graft-related complications.

CONCLUSION

Open repair of infrarenal AAAs can achieve satisfactory 15-year follow-up rates of survival free from reintervention for any graft-related complications, suggesting that surgery should still be considered the procedure of choice for infrarenal AAAs, at least in patients who are fit for surgery.

Abdominal aortic aneurysm screening using a hand-held ultrasound device. "A pilot study"

This study shows the usefulness of a small, portable hand-held echo ultrasound device for the screening for abdominal aortic aneurysms.

Abdominal aortic aneurysm repair

Newer, minimally invasive catheter-based endovascular technology utilizing stent grafts are currently being evaluated for abdominal aortic aneurysm (AAA) repair. A retrospective review of all (3 years) consecutive, non-ruptured elective AAA repairs was undertaken to document the results of AAA surgical repair in a modern cohort of patients to allow a contemporary comparison with the evolving endoluminal data. One hundred twenty-one AAAs were identified in a male veteran population. Mean age was 68.5 +/-7.7 years. Medical history review showed hypertension in 55%, heart disease in 73.5%, peripheral vascular disease in 21%, stroke and transient ischemic attacks in 22%, diabetes mellitus in 7%, renal insufficiency in 10%, and smoking history in 80%. The AAA size was documented with ultrasound (5.2 +/-1.3 cm, n=40) and computed tomography (5.6 +/-1.3 cm, n=100). Fifty-nine percent had angiography. Intraoperative end points included an operative time of 165 +/-6.3 minutes from incision to dressing placement. A Dacron tube graft was used in 78%, the remaining were Dacron bifurcated grafts. A suprarenal clamp was used in 8% for proximal aortic control with juxtarenal aneurysms. A pulmonary-artery catheter was placed in 69%. A transverse incision was used in 69% of patients and a midline incision was used in the rest. Estimated blood loss was 1505 +/-103 mL; cell saver blood returned 754 +/-53 mL; crystalloid/Hespan 4771 +/-176 mL; banked packed red blood cells 0.75 +/-0.11 U. Time to extubation was, in the operating room (78.5%), on the day of the operation (5.0%), postoperative day (POD) 1 (12.4%), POD2 (1.7%), POD3 (0.8%), and one case was performed with epidural anesthesia only. Postoperative end points included a 30-day mortality rate of 1.6% (two patients). Postoperative morbidity included wound dehiscence 0.8%; sepsis, urinary tract infection, wound infection, leg ischemia, ischemic colitis, and stroke each had an incidence of 1.6%; myocardial infarction, congestive heart failure, pneumonia, re-operation for suspected bleeding, and ileus or bowel obstruction occurred with an incidence of 3.3%. No significant increase in serum creatinine levels was noted. Time to enteral fluids/nutrition was 3.5 +/-0.08 days. Patients were out of bed to a chair or walking by 1.3 +/-0.06 days postoperatively. The length of stay in the intensive care unit (ICU) was 2.0 +/-0.12 days and postoperative hospital stay was 6.6 +/- 0.33 days. Transfusion requirement for the hospital stay was 1.6 +/-0.2 U per patient. This review highlights a cohort of male veteran patients with significant cardiac co-morbidity who have undergone repair with a conventional open technique and low mortality and morbidity rates. This group had rapid extubation, time to oral intake, and ambulation. In addition, ICU and hospital stays were relatively short.

Aortic aneurysm diameter and risk of cardiovascular mortality

After successful surgical repair of an abdominal aortic aneurysm, patients have for many years an increased risk of death from cardiovascular causes. We have tested the hypothesis that for patients with abdominal aortic aneurysms, the risk of nonaneurysm cardiovascular mortality before and after surgery increased with aneurysm diameter. Records of aneurysm repair or rupture and mortality were available from 2305 patients entered into the UK Small Aneurysm Trial and Study. Two hundred fifty-nine deaths occurred before aneurysm repair or rupture (mean follow-up 1.7 years), and 325 occurred after surgical repair (mean follow-up 3.6 years). The risk of nonaneurysm-related mortality and cardiovascular death before and after surgery increased with aneurysm diameter at baseline, even after adjustment for other known risk factors. The adjusted hazard ratios for cardiovascular mortality, per standard deviation (0.8-cm) increase in aneurysm diameter, were 1.34 (95% CI 1.01 to 1.79) and 1.31 (95% CI 1.06 to 1.63) in the periods before aneurysm repair or rupture and after aneurysm repair, respectively. The significant association between aortic diameter and cardiovascular mortality, excluding aneurysm-related deaths, suggests that aneurysm diameter is an independent marker of cardiovascular disease risk.

Surgical management of abdominal aortic aneurysm

Abdominal aortic aneurysms (AAA) are increasingly common in the aging population. While the etiology of abdominal aortic aneurysms is unknown, there is growing evidence that suggests an immune response. The majority of AAA are asymptomatic and when treated are standard open surgical procedures. The overall mortality rate is 5% or less. The current recommendations for the treatment of aneurysms are based on diameter: diameters exceeding 5 cm in good-risk younger patients should be treated. Aortic aneurysms tend to enlarge over time with a growth-rate between 0.2 and 0.4 mm per year. Once rupture occurs mortality is estimated to exceed 75%, with half of the patients dying prior to arriving at the hospital and the remaining one-half following surgical correction. Recently, minimally invasive techniques have been developed to treat AAA in high-risk patients. These techniques involve the use of covered stented grafts. Current clinical investigations are underway both in this country and in Europe, which have yielded promising results. However, long-term complications are unknown. Currently, aortic aneurysms are best treated with open surgical management.

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.

Endoleak as a predictor of outcome after endovascular aneurysm repair: AneuRx multicenter clinical trial

OBJECTIVE

The purpose of this study was to determine whether evidence of blood flow in the aneurysm sac (endoleak) is a meaningful predictor of clinical outcome after successful endovascular aneurysm repair.

METHODS

We reviewed all patients in Phase II of the AneuRx Multicenter Clinical Trial with successful stent graft implantation and predischarge contrast computed tomographic (CT) imaging. The clinical outcome of patients with evidence of endoleak was compared with the outcome of patients without evidence of endoleak. The CT endoleak status before hospital discharge at 6, 12, and 24 months was determined by each clinical center as well as by an independent core laboratory. Endoleak status at 1 month was assessed with duplex scanning examination or CT at each center without confirmation by the core laboratory.

RESULTS

Centers reported endoleaks in 152 (38%) of 398 patients on predischarge CT, whereas the core laboratory reported endoleaks in 50% of these patients (P <.001). The center-reported endoleak rate decreased to 13% at 1 month. Follow-up extended to 2 years (mean, 10 +/- 4 months). One patient had aneurysm rupture and underwent successful open repair at 14 months. This patient had a Type I endoleak at discharge but no endoleak at 1 month or at subsequent follow-up times. There were no differences between patients with and patients without endoleak at discharge in the following outcome measures: patient survival, aneurysm rupture, surgical conversion, the need for an additional procedure for endoleak or graft patency, aneurysm enlargement more than 5 mm, the appearance of a new endoleak, or stent graft migration. Despite a higher endoleak rate identified by the core laboratory, neither the endoleak rate reported by the core laboratory nor the endoleak rate reported by the center at discharge was significantly related to subsequent outcome measures. Patients with endoleak at 1 month were more likely to undergo an additional procedure for endoleak than patients without endoleaks. Patients with Type I endoleaks at discharge and patients with endoleak at 1 month were more likely to experience aneurysm enlargement at 1 year. However, there was no difference in patient survival, aneurysm rupture rate, or primary or secondary success rate between patients with or without endoleak. Actuarial survival of all patients undergoing endovascular aneurysm repair was 96% at 1 year and was independent of endoleak status. Primary outcome success was 92% at 12 months and 88% at 18 months. Secondary outcome success was 96% at 12 months and 94% at 18 months.

CONCLUSIONS

The presence or absence of endoleak on CT scan before hospital discharge does not appear to predict patient survival or aneurysm rupture rate after endovascular aneurysm repair using the AneuRx stent graft. Although the identification of blood flow in the aneurysm sac after endovascular repair is a meaningful finding and may at times indicate inadequate stent graft fixation, the usefulness of endoleak as a primary indicator of procedural success or failure is unclear. Therefore, all patients who have undergone endovascular aneurysm repair should be carefully followed up regardless of endoleak status.

Peroperative factors influencing the outcome of elective abdominal aorta aneurysm repair

PURPOSE

To identify perioperative variables which may influence mortality of elective abdominal aneurysm repair (AAA).

METHOD

prospective study of patients undergoing elective AAA repair between 1986 and 1997.

RESULTS

Four hundred and seventy patients (438 men, 32 females) with a mean age of 69.4+/-13 years and aneurysms with a diameter of 60+/-3 mm were operated on with a 1-month mortality rate of 5.3%. Multivariate analysis identified the following independent risk factors for mortality: age >70 (p<0.0001), a past history of myocardial infarction (p<0.0001), preoperative renal insufficiency (p<0.0001), reoperation (p<0.0001), colonic necrosis (p<0.0001), and severe postoperative medical complications (p<0.0001).

CONCLUSION

Intra- and postoperative events affect the outcome of AAA repair, independently of preoperative factors, and should be described when presenting the results of AAA repair.

Long-term survival following emergency abdominal aortic aneurysm repair

Survival following emergency surgery for ruptured abdominal aortic aneurysm remains poor and is in stark contrast to that for elective repair. We have carried out a 5-year retrospective observational study to determine the long-term (5-year) survival of patients following emergency surgery for ruptured abdominal aortic aneurysm at a district general hospital in East Anglia. A total of 99 patients presented to the operating theatre for emergency repair of ruptured abdominal aortic aneurysm in this 5-year study period. In-hospital mortality was 70% and was unchanged over the 5 years. Overall long-term survival in those patients discharged from hospital was good. The ICU cost per long-term survivor was calculated to be pound sterling 36750.

Management of abdominal aortic aneurysms

Rupture of an abdominal aortic aneurysm (AAA) remains a common vascular catastrophe in all emergency departments. Currently, the natural history of AAAs indicates that risk of rupture increases considerably when the aneurysm is greater than 5 cm in diameter. Appropriate management of aneurysms is elective repair for patients with a good operative risk whose aneurysm is between 5 and 6 cm. For patients with a serious medical comorbidity, the threshold for AAA repair is usually 6 cm. Surgical management is generally safe with extraordinarily durable results. Another current option is an investigational endovascular stent graft, but the long-term outcome for these new devices remains unknown. In addition, optimal medical management should include careful control of hypertension and smoking cessation. The current prognosis for healthy patients who undergo elective aneurysm repair is excellent.

Is Surgery Justifiable for Treatment of Small Abdominal Aortic Aneurysms?

Patients who underwent elective surgery for abdominal aortic aneurysms between January 1990 and December 1996 were evaluated retrospectively. Forty-six patients (group 1) with aneurysms of less than 5 cm in diameter were compared with 121 patients (group 2) with larger aneurysms. There were no differences in age, sex, or associated pathology between the two groups. Hypertension, coronary artery disease, and chronic obstructive lung disease were the most frequently associated conditions. Hospital mortality was not significantly different; 4.3% for group 1 and 2.5% for group 2. At 7 years, the cumulative long-term survival rates for group 1 and group 2 were 97% and 90% respectively (p > 0.05). For any infrarenal aortic aneurysm, indication for surgery should be based on the rate of aneurysm expansion, development of increased aneurysm-related symptoms or complications, and patient anxiety.

Mid-term results of a second generation bifurcated endovascular graft for abdominal aortic aneurysm repair: the French Vanguard trial

PURPOSE

The purpose of this study was to evaluate prospectively the results of the bifurcated Vanguard endovascular graft for abdominal aortic aneurysm (AAA) repair.

METHODS

Seventy-five patients, with a median age of 69.6 years (range, 48 to 88 years) and asymptomatic AAAs, were recruited in 14 French vascular institutions. An independent committee validated the indications for endovascular repair, and all the implantations were supervised by a well-trained medico-technical assistant. Further independent committees reviewed patient data, clinical data, and imaging follow-up examination. The main endpoints were implantation success, mortality, morbidity, reinterventions, and aneurysm evolution assessed with serial computed tomographic (CT) scanning.

RESULTS

All the grafts were successfully implanted, resulting in a 100% success rate on an intent-to-treat basis. At discharge, there were no deaths, six significant local complications (8%) that necessitated surgery, no vascular complications, and six systemic complications (8%). The average durations of intensive care unit and hospital stays were 26 +/- 6 hours and 6 +/- 2.54 days, respectively. Predischarge CT scan results showed five type I and 18 type II endoleaks (total, 30%). At the end of the follow-up period (mean duration, 18.35 +/- 4.12 months; range, 17 days to 24 months), seven patients (9%) had died: one from sepsis, five from unrelated causes, and one from aneurysm rupture. The 2-year cumulative survival rate was 86% +/- 5.9%. Twenty-one subsequent endovascular or vascular procedures were necessitated (28%) in 17 patients (23%) to treat graft limb occlusion or stenosis (n = 9 patients) or to seal an endoleak (n = 8 patients). The 2-year cumulative survival rate free of reintervention was 67% +/- 7%. On CT scans, the mean AAA diameter decreased from 54 mm +/- 8.9 (range, 45 to 80 mm) before surgery to 51.6 mm +/- 9.1 at 6 months and to 43.4 mm +/- 4.4 at the end of the follow-up period (P =.001). Persistent endoleak was significantly associated with an increase in diameter (4 of 5 [80%] vs 1 of 47 [2%]; P =.001).

CONCLUSION

In selected patients, the bifurcated Vanguard endovascular graft may be implanted with a low mortality and morbidity rate and a favorable mid-term survival rate. The decrease of the aneurysm size is a strong argument in favor of the efficiency of the device. However, lasting endoleaks with increased aneurysm diameter and occurrence of limb graft stenosis or occlusion raise concerns and justify a careful long-term follow-up monitoring of all patients who undergo treatment with endovascular technique.

The value of late computed tomographic scanning in identification of vascular abnormalities after abdominal aortic aneurysm repair

PURPOSE

The purpose of this study was to determine the prevalence of late arterial abnormalities after aortic aneurysm repair and thus to suggest a routine for postoperative radiologic follow-up examination and to establish reference criteria for endovascular repair.

METHODS

Computed tomographic (CT) scan follow-up examination was obtained at 8 to 9 years after abdominal aortic aneurysm (AAA) repair on a cohort of patients enrolled in the Canadian Aneurysm Study. The original registry consisted of 680 patients who underwent repair of nonruptured AAA. When the request for CT scan follow-up examination was sent in 1994, 251 patients were alive and potentially available for CT scan follow-up examination and 94 patients agreed to undergo abdominal and thoracic CT scanning procedures. Each scan was interpreted independently by two vascular radiologists.

RESULTS

For analysis, the aorta was divided into five defined segments and an aneurysm was defined as a more than 50% enlargement from the expected normal value as defined in the reporting standards for aneurysms. With this strict definition, 64.9% of patients had aneurysmal dilatation and the abnormality was considered as a possible indication for surgical repair in 13.8%. Of the 39 patients who underwent initial repair with a tube graft, 12 (30.8%) were found to have an iliac aneurysm and six of these aneurysms (15.4%) were of possible surgical significance. Graft dilatation was observed from the time of operation (median graft size of 18 mm) to a median size of 22 mm as measured by means of CT scanning at follow-up examination. Fluid or thrombus was seen around the graft in 28% of the cases, and bowel was believed to be intimately associated with the graft in 7%.

CONCLUSION

Late follow-up CT scans after AAA repair often show vascular abnormalities. Most of these abnormalities are not clinically significant, but, in 13.8% of patients, the thoracic or abdominal aortic segment was aneurysmal and, in 15.4% of patients who underwent tube graft placement, one of the iliac arteries was significantly abnormal to warrant consideration for surgical repair. On the basis of these findings, a routine CT follow-up examination after 5 years is recommended. This study provides a population-based study for comparison with the results of endovascular repair.

Influence of study design on reported mortality and morbidity rates after abdominal aortic aneurysm repair

BACKGROUND

The mortality and morbidity rates of elective abdominal aortic aneurysm (AAA) surgery, as reported over the past 12 years, were graded and analysed by levels of evidence.

METHODS

Articles on elective AAA surgery published between 1985 and 1996 were retrieved and classified into five levels of evidence. Level 1 contains prospective studies and is subdivided into population-based (level 1a) and hospital-based (level 1b) studies. Level 2 includes retrospective studies, subdivided into population-based studies (level 2a), hospital-based studies (level 2b) and hospital-based studies concerning a specified group of selected patients (level 2c). Operative mortality and systemic and local/vascular complication rates with 95 per cent confidence intervals were calculated for each level of evidence.

RESULTS

Seventy-two articles describing a total of 37 654 patients could be included: two level 1a studies (692 patients), nine level 1b studies (1677 patients), 13 level 2a studies (21 409 patients), 32 level 2b studies (12019 patients) and 16 level 2c studies (1857 patients). The mean 30-day mortality rates of the two population-based levels were similar: 8.2 (95 per cent confidence interval 6.4-10.6) per cent for the prospective (la) and 7.4 (7.0-7.7) per cent for the retrospective (2a) series. These figures were significantly higher than the remarkably similar hospital-based mortality rates: 3.8 (3.0-4.8) per cent for the prospective (1b), 3.8 (3.5-4.2) per cent for the retrospective (2b) and 3.5 (2.8-4.4) per cent for selected patient group (2c) studies. The most frequent complication was of cardiac origin. In the population-based series the cardiac complication rates were 10.6 (8.5-13.2) and 11.1 (9.1-13.6) per cent for levels 1a and 2a respectively. This compared well with 12.0 (10.5-13.9) per cent for the prospective hospital-based series (level 1b). The cardiac complication rates in the retrospective hospital-based studies were significantly lower: 8.9 (8.4-9.5) and 6.1 (4.9-7.6) per cent for levels 2b and 2c respectively.

CONCLUSION

There is a clear and consistent disagreement in reported mortality rates between hospital-based and population-based studies of elective surgery for AAA. Prospective studies give the best documentation of postoperative morbidity.

Mortality results for randomised controlled trial of early elective surgery or ultrasonographic surveillance for small abdominal aortic aneurysms. The UK Small Aneurysm Trial Participants

BACKGROUND

Early elective surgery may prevent rupture of abdominal aortic aneurysms, but mortality is 5-6%. The risk of rupture seems to be low for aneurysms smaller than 5 cm. We investigated whether prophylactic open surgery decreased long-term mortality risks for small aneurysms.

METHODS

We randomly assigned 1090 patients aged 60-76 years, with symptomless abdominal aortic aneurysms 4.0-5.5 cm in diameter to undergo early elective open surgery (n=563) or ultrasonographic surveillance (n=527). Patients were followed up for a mean of 4.6 years. If the diameter of aneurysms in the surveillance group exceeded 5.5 cm, surgical repair was recommended. The primary endpoint was death. Mortality analyses were done by intention to treat.

FINDINGS

The two groups had similar cardiovascular risk factors at baseline. 93% of patients adhered to the assigned treatment. 309 patients died during follow-up. The overall hazard ratio for all-cause mortality in the early-surgery group compared with the surveillance group was 0.94 (95% CI 0.75-1.17, p=0.56). The 30-day operative mortality in the early-surgery group was 5.8%, which led to a survival disadvantage for these patients early in the trial. Mortality did not differ significantly between groups at 2 years, 4 years, or 6 years. Age, sex, or initial aneurysm size did not modify the overall hazard ratio.

INTERPRETATION

Ultrasonographic surveillance for small abdominal aortic aneurysms is safe, and early surgery does not provide a long-term survival advantage. Our results do not support a policy of open surgical repair for abdominal aortic aneurysms of 4.0-5.5 cm in diameter.

The fate of patients undergoing surveillance of small abdominal aortic aneurysms

OBJECTIVES

Increasing numbers of patients with small abdominal aortic aneurysms (AAA) are being diagnosed. The aim of this paper is to define the fate of those patients undergoing surveillance of small AAAs.

SETTING

U.K. district general hospital.

METHODS

A prospective study has been carried out of all patients undergoing surveillance. At the time of the first consultation the patient was assessed, a Detsky score calculated and the referral source noted. End points of the study were elective repair of the aneurysm, aneurysm rupture or death of the patient.

RESULTS

Details of 267 patients were analysed. The referral source was general practitioner in 39%, patients with peripheral vascular disease in 32% and department of urology in 21%. None were referred from population screening. The cumulative 5-year risks of rupture, elective repair or non-AAA related deaths were 15%, 26% and 46% for all patients, 4%, 13% and 38% for patients initially presenting with AAA less than 4 cm diameter and 21%, 42% and 54% for patients presenting with an AAA 4-5.5 cm diameter. All but one of 11 patients whose aneurysm ruptured were unfit or had declined elective repair. There were 56 non-AAA related deaths, the majority due to cardiovascular causes. Those patients with low Detsky scores had a 5-year survival of 62%, those with high scores 44%. The age/sex matched survival or a normal population at 5 years in 80%.

CONCLUSION

Overall the non-AAA related mortality was greater than the risks of rupture or elective repair. It is important to bear in mind the poor prognosis of this group of patients compared with a normal population when considering elective repair of small AAAs.

Complications of standard elective abdominal aortic aneurysm repair

OBJECTIVE

To evaluate complications of standard elective repair of infrarenal abdominal aortic aneurysms.

DESIGN

Prospective multicentre study.

MATERIALS

Two-hundred and ninety-one consecutive patients undergoing standard elective surgery for an infrarenal aortic aneurysm.

METHODS

Recording adverse events according to the recommendations of the Ad Hoc Committee on Reporting Standards.

RESULTS

Seventy-five patients (26%) experienced some complication following elective aortic aneurysm surgery. Twenty-two patients had a mild complication (7.6%, 95% C.I. 4.8-11.2%), 27 a moderate (9.3%, 95% C.I. 6.2-13.2%) and 26 patients had a severe and/or fatal complication (8.9%, 95% C.I. 5.9-12.8%). The in-hospital mortality was 4.1% (12 patients, 95% C.I. 2.2-7.1%). Cardiac failure was the commonest primary cause for death (58%). Twenty-two per cent of the patients had a non-fatal complication: the most frequent being pulmonary (10%) and cardiac (10%). Patients with a history of cardiac events had a five times higher risk of a fatal outcome (95% C.I. 1.1-24.0) and a two and a half times higher risk of any severe fatal or non-fatal complication (95% C.I. 1.0-6.5). Other risk factors were advancing age and the presence of pulmonary disease.

CONCLUSIONS

In addition to mortality, morbidity figures of standard aneurysm operations are important, as well as associated risk factors. This is especially true when evaluating early repair of small aneurysms and new endovascular techniques.

Relationship between abdominal aortic aneurysm wall compliance and clinical outcome: a preliminary analysis

BACKGROUND

Aortic compliance, as measured by the pressure-strain elastic modulus (Ep) and stiffness (B), may allow a more precise estimate of abdominal aortic aneurysm rupture risk than size alone.

AIM

To determine the relationships between AAA compliance, size, growth, and clinical outcome.

METHODS

One-hundred and twelve patients with initially non-operated AAA (86 men, 26 women, mean age 73 years), recruited from five centres, underwent baseline compliance measurements and were then followed for a median of 7 (range 2-18) months; 85 patients underwent repeated measurements (median 3, range 2-5) 3-6-monthly over a median of 12 (range 3-18 months).

RESULTS

Seven patients have ruptured and 16 have undergone repair of non-ruptured AAA. AAA that ruptured had significantly lower Ep and B (more compliant). In AAA that ruptured or required repair there was an inverse relationship between diameter and Ep and B. In those undergoing repeated measurements AAA expansion was only associated with a significant increase in Ep and B in non-operated patients.

CONCLUSIONS

Baseline AAA compliance was significantly related to rupture and the future requirement for operative repair. Failure of compliance to increase with size may be a marker for rapid growth, developmental symptoms and rupture.

Operative repair for aortic aneurysms: the gold standard

Surgical treatment of abdominal aortic aneurysm (AAA) is being challenged by newer, minimally invasive therapies. Such new treatment strategies will need to prove themselves against concurrent results of standard operative AAA repair, within defined medical risk and aneurysm morphological categories. We review the natural history of AAAs, the medical risk levels for elective AAA repair, aneurysm morphology and its impact on operative mortality, the issue of high-risk patient treatment, and the current standard of care for AAAs based on single-center, multicenter, and population-based statistics. In good-risk patients, aneurysms > 5 cm in diameter are best treated by replacement with a prosthetic graft. Operative mortality should be < 5% 1-year survival > 90%. Aortic endograft techniques must meet or exceed these standards if they are to supplant standard surgical repair.

A prospective survey of patients presenting with abdominal aortic aneurysm

OBJECTIVES

To define the presentation and management of patients presenting with abdominal aortic aneurysm (AAA) DESIGN AND SETTING: A prospective survey was carried out of all patients presenting to hospitals within the Oxford region.

MATERIALS AND METHODS

Data were collected by one surgeon in each hospital. Full details were collected onto data sheets.

RESULTS

One hundred and ninety patients presented, 141 electively, 46 with ruptured AAA and three with acute AAAs. In 53 patients presenting electively the aneurysm was small and surveillance started. Fifty-six patients underwent an operation, three patients died. Of 46 patients with a ruptured aneurysm 24 (52%) died. In 11 no operation was carried out and all of these patients died within 24 h. Operative mortality was 13 of 35 patients (37%). More patients with a ruptured AAA were transferred to the teaching hospital compared with a district general hospital (p < 0.05). This was reflected in a lower operative mortality in the teaching hospital.

CONCLUSIONS

The presentation of AAA in this study was approximately 15 per 100,000 population. Approximately one-third of patients presenting electively had small AAAs which required surveillance. A further third underwent an operation, the remaining patients being unfit. Approximately one-quarter of patients with a ruptured aneurysm did not undergo an operation. The operative mortality was 37%.

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.