The influence of aneurysm size on perioperative cardiac outcome in elective open infrarenal aortic aneurysm repair

Asymptomatic myocardial injury identified on postoperative troponin testing after open or endovascular surgical procedures is a predictor of mortality

OBJECTIVE

Elevated troponin (TnT) levels after open or endovascular surgical procedures have been previously shown to correlate with significantly higher postoperative and short-term mortality. The incidence of asymptomatic myocardial injury after vascular surgical procedures has also been shown to be high. The aim of the present study was to evaluate the utility of routine postoperative TnT screening and long-term outcomes for patients with postoperative TnT elevation.

METHODS

Data from consecutive patients who had undergone open or endovascular surgery on an emergent or elective basis with routine postoperative TnT testing from January 2010 to December 2012 were retrospectively analyzed. Elevated postoperative TnT was considered >0.01 ng/mL. Patients with no documented postoperative TnT levels, those who had denied research authorization, and those with elevated TnT levels secondary to renal insufficiency alone were excluded. Patients were also excluded if they had required a dialysis access procedure, varicose vein procedure, or any procedure performed on an outpatient basis, because these were considered nonmajor surgeries. The end points were all-cause mortality at 30 days and 1, 2, 4, and 8 years postoperatively. Mortality data were retrieved from the electronic medical records and the Social Security Death Index and Accurint Death database.

RESULTS

During the 3-year study period, 1632 patients with postoperative TnT levels available had met the inclusion criteria (70% men; 30% women; mean age, 69.7 years). Postoperatively, 410 patients (25.1%) had had elevated TnT levels (TnT+) and 1222 (74.9%) had had nonelevated TnT levels (TnT-). Of the 410 TnT+ patients, 261 had undergone open, 143 had undergone endovascular, and 6 had undergone hybrid procedures. These included 180 aortic, 128 infrainguinal, 22 cerebrovascular, and 80 upper extremity or miscellaneous procedures. Of the 410 TnT+ patients, 168 had experienced asymptomatic myocardial injury. The 30-day mortality was significantly higher for the TnT+ patients than for the TnT- patients (3.9% vs 0.8%; P < .001). The cumulative probability of death for the TnT+ patients remained significantly higher than that for the TnT- patients at 1 (13% vs 3.2%), 2 (17.8% vs 4.8%), 4 (43% vs 18.5%), and 8 (81.4% vs 48.6%) years (P < .0001). The difference held true even for the 168 asymptomatic TnT+ patients compared with the TnT- patients at 30 days (2.4% vs 0.8%) and 1 (7.6% vs 3.2%), 2 (13.3% vs 4.8%), 4 (43.6 vs 18.5%) and 8 (80.8 vs 48.6%) years (P < .0001).

CONCLUSIONS

In the present study, patients with elevated TnT levels after vascular surgery had had significantly higher early and late all-cause mortality compared with those with normal postoperative TnT levels. This was true even for patients with asymptomatic TnT elevation, suggesting a role might exist for routine postoperative TnT screening to allow for long-term risk stratification and targeted medical management.

Major Adverse Cardiac Events after Elective Infrarenal Endovascular Aortic Aneurysm Repair

OBJECTIVE

There is a significant cardiac morbidity and mortality after endovascular aneurysm repair (EVAR). However, information about long-term risk of cardiac events after EVAR and potential predictors is lacking. Therefore, the aim of this study was to determine incidence and predictors of major adverse cardiac events (MACE) at one- and five-years after elective EVAR for infrarenal abdominal aortic aneurysms.

METHODS

Baseline, perioperative and postoperative information of 320 patients was evaluated. The primary outcome was the incidence of MACE after EVAR, which was defined as acute coronary syndrome, unstable angina pectoris, de novo atrial fibrillation, hospitalization for heart failure, mitral valve insufficiency, revascularization (including PCI and CABG), as well as cardiovascular and non-cardiovascular death. Kaplan Meier analysis was performed to determine incidences of MACE, MACE excluding non-cardiovascular death and cardiac events by excluding non-cardiovascular and vascular death from MACE. Predictors of MACE were identified using univariate and multivariate binary regression analysis.

RESULTS

Through one- and five-years follow-up after EVAR, freedom from MACE was 89.4% (standard error (SE) 0.018) and 59.8% (SE 0.033), freedom from MACE excluding non-cardiovascular death was 94.7% (SE 0.013) and 77.5% (SE 0.030) and freedom from cardiac events was 96.0% (SE 0.011) and 79.1% (SE 0.030), respectively. Predictors for MACE within one-year were American Society of Anaesthesiologists (ASA) score 3 or 4 (OR, 3.17; 95% CI, 1.52-6.59) and larger abdominal aortic diameter (OR, 1.04; 95% CI, 1.01-1.08). History of atrial fibrillation (OR, 0.14; 95% CI, 0.03-0.60) was a negative predictor factor. Predictors for MACE through five-years were history of heart failure (OR, 4.10; 95% CI 1.36-12.32) and valvular heart disease (OR, 2.31; 95% CI, 0.97-5.51), ASA score 3 or 4 (OR, 1.66; 95% CI, 0.96-2.88) and older age (OR, 1.04; 95% CI, 1.01-1.08).

CONCLUSION

MACE is a common complication during the first five-years after elective EVAR. Cardiac diseases at baseline are strong predictors for long-term MACE and potentially helpful in optimizing future post-operative long-term follow-up.

The comparative and added prognostic value of biomarkers to the Revised Cardiac Risk Index for preoperative prediction of major adverse cardiac events and all-cause mortality in patients who undergo noncardiac surgery

BACKGROUND

The Revised Cardiac Risk Index (RCRI) is a widely acknowledged prognostic model to estimate preoperatively the probability of developing in-hospital major adverse cardiac events (MACE) in patients undergoing noncardiac surgery. However, the RCRI does not always make accurate predictions, so various studies have investigated whether biomarkers added to or compared with the RCRI could improve this.

OBJECTIVES

Primary: To investigate the added predictive value of biomarkers to the RCRI to preoperatively predict in-hospital MACE and other adverse outcomes in patients undergoing noncardiac surgery. Secondary: To investigate the prognostic value of biomarkers compared to the RCRI to preoperatively predict in-hospital MACE and other adverse outcomes in patients undergoing noncardiac surgery. Tertiary: To investigate the prognostic value of other prediction models compared to the RCRI to preoperatively predict in-hospital MACE and other adverse outcomes in patients undergoing noncardiac surgery.

SEARCH METHODS

We searched MEDLINE and Embase from 1 January 1999 (the year that the RCRI was published) until 25 June 2020. We also searched ISI Web of Science and SCOPUS for articles referring to the original RCRI development study in that period.

SELECTION CRITERIA

We included studies among adults who underwent noncardiac surgery, reporting on (external) validation of the RCRI and: - the addition of biomarker(s) to the RCRI; or - the comparison of the predictive accuracy of biomarker(s) to the RCRI; or - the comparison of the predictive accuracy of the RCRI to other models. Besides MACE, all other adverse outcomes were considered for inclusion.

DATA COLLECTION AND ANALYSIS

We developed a data extraction form based on the CHARMS checklist. Independent pairs of authors screened references, extracted data and assessed risk of bias and concerns regarding applicability according to PROBAST. For biomarkers and prediction models that were added or compared to the RCRI in ≥ 3 different articles, we described study characteristics and findings in further detail. We did not apply GRADE as no guidance is available for prognostic model reviews.

MAIN RESULTS

We screened 3960 records and included 107 articles.   Over all objectives we rated risk of bias as high in ≥ 1 domain in 90% of included studies, particularly in the analysis domain. Statistical pooling or meta-analysis of reported results was impossible due to heterogeneity in various aspects: outcomes used, scale by which the biomarker was added/compared to the RCRI, prediction horizons and studied populations.  Added predictive value of biomarkers to the RCRI Fifty-one studies reported on the added value of biomarkers to the RCRI. Sixty-nine different predictors were identified derived from blood (29%), imaging (33%) or other sources (38%). Addition of NT-proBNP, troponin or their combination improved the RCRI for predicting MACE (median delta c-statistics: 0.08, 0.14 and 0.12 for NT-proBNP, troponin and their combination, respectively). The median total net reclassification index (NRI) was 0.16 and 0.74 after addition of troponin and NT-proBNP to the RCRI, respectively. Calibration was not reported. To predict myocardial infarction, the median delta c-statistic when NT-proBNP was added to the RCRI was 0.09, and 0.06 for prediction of all-cause mortality and MACE combined. For BNP and copeptin, data were not sufficient to provide results on their added predictive performance, for any of the outcomes. Comparison of the predictive value of biomarkers to the RCRI  Fifty-one studies assessed the predictive performance of biomarkers alone compared to the RCRI. We identified 60 unique predictors derived from blood (38%), imaging (30%) or other sources, such as the American Society of Anesthesiologists (ASA) classification (32%). Predictions were similar between the ASA classification and the RCRI for all studied outcomes. In studies different from those identified in objective 1, the median delta c-statistic was 0.15 and 0.12 in favour of  BNP and NT-proBNP alone, respectively, when compared to the RCRI, for the prediction of MACE. For C-reactive protein, the predictive performance was similar to the RCRI. For other biomarkers and outcomes, data were insufficient to provide summary results. One study reported on calibration and none on reclassification. Comparison of the predictive value of other prognostic models to the RCRI   Fifty-two articles compared the predictive ability of the RCRI to other prognostic models. Of these, 42% developed a new prediction model, 22% updated the RCRI, or another prediction model, and 37% validated an existing prediction model. None of the other prediction models showed better performance in predicting MACE than the RCRI. To predict myocardial infarction and cardiac arrest, ACS-NSQIP-MICA had a higher median delta c-statistic of 0.11 compared to the RCRI. To predict all-cause mortality, the median delta c-statistic was 0.15 higher in favour of ACS-NSQIP-SRS compared to the RCRI. Predictive performance was not better for CHADS₂, CHA₂DS₂-VASc, R₂CHADS₂, Goldman index, Detsky index or VSG-CRI compared to the RCRI for any of the outcomes. Calibration and reclassification were reported in only one and three studies, respectively.

AUTHORS' CONCLUSIONS

Studies included in this review suggest that the predictive performance of the RCRI in predicting MACE is improved when NT-proBNP, troponin or their combination are added. Other studies indicate that BNP and NT-proBNP, when used in isolation, may even have a higher discriminative performance than the RCRI. There was insufficient evidence of a difference between the predictive accuracy of the RCRI and other prediction models in predicting MACE. However, ACS-NSQIP-MICA and ACS-NSQIP-SRS outperformed the RCRI in predicting myocardial infarction and cardiac arrest combined, and all-cause mortality, respectively. Nevertheless, the results cannot be interpreted as conclusive due to high risks of bias in a majority of papers, and pooling was impossible due to heterogeneity in outcomes, prediction horizons, biomarkers and studied populations. Future research on the added prognostic value of biomarkers to existing prediction models should focus on biomarkers with good predictive accuracy in other settings (e.g. diagnosis of myocardial infarction) and identification of biomarkers from omics data. They should be compared to novel biomarkers with so far insufficient evidence compared to established ones, including NT-proBNP or troponins. Adherence to recent guidance for prediction model studies (e.g. TRIPOD; PROBAST) and use of standardised outcome definitions in primary studies is highly recommended to facilitate systematic review and meta-analyses in the future.

Statins reduce mortality after abdominal aortic aneurysm repair: A systematic review and meta-analysis

OBJECTIVE

The necessity and efficacy of statin treatment for abdominal aortic aneurysm (AAA) remains controversial. This systematic review and meta-analysis was conducted to investigate the effects of statin therapy on the outcomes of patients with AAA.

METHODS

The Cochrane library, Embase, and MedLine were searched comprehensively to identify relevant cohort studies and randomized controlled trials. The primary outcomes included short- and long-term mortality after AAA repair, and secondary outcomes included the incidence of perioperative cardiovascular complications, sac shrinkage after endovascular aneurysm repair, and the growth rate of the aneurysms. Short-term mortality was defined as all-cause 30-day or in-hospital postoperative mortality. Long-term mortality was defined as the all-cause mortality at the end of follow-up period (≥1 year). A random effects model was used to combine the results of included studies. Forest plots were created to show the pooled results of each outcome.

RESULTS

One post hoc analysis of a randomized trial and 36 cohort studies (n = 134,290 patients) were included in this systematic review. The average score of included studies by Newcastle-Ottawa Scale was 7.76. Patients taking or not taking statin therapy were all diagnosed with unruptured AAA, and 59.9% of these patients were given statin therapy. Compared with statin nonusers, patients in statin therapy had significantly lower long-term mortality (odds ratio, 0.67; 95% confidence interval, 0.59-0.75; P < .001; I² = 71.7%), and short-term mortality after aneurysmal repair (odds ratio, 0.51; 95% confidence interval, 0.36-0.73; P < .001; I² = 81.4%). No significant difference was found between patients taking or not taking statin treatment on perioperative cardiovascular complications or sac shrinkage after endovascular aneurysm repair or growth rate of AAA under surveillance.

CONCLUSIONS

These findings suggest that statin use is associated with a significant decrease in long- and short-term mortality in patients after AAA repair. Based on these results, statin therapy is worth being used in clinical practice for the management of AAA.

Statins Reduce Abdominal Aortic Aneurysm Growth, Rupture, and Perioperative Mortality: A Systematic Review and Meta-Analysis

Background

There are no recognized pharmacological treatments for abdominal aortic aneurysms (AAA), although statins are suggested to be beneficial. We sought to summarize the literature regarding the effects of statins on human AAA growth, rupture, and 30‐day mortality.

Methods and Results

We conducted a systematic review and meta‐analysis of randomized and observational studies using the Cochrane CENTRAL database, MEDLINE, and EMBASE up to June 15, 2018. Review, abstraction, and quality assessment were conducted by 2 independent reviewers, and a third author resolved discrepancies. Pooled mean differences and odds ratios with 95% confidence intervals were calculated using random effects models. Heterogeneity was quantified using the I² statistic, and publication bias was assessed using funnel plots. Our search yielded 911 articles. One case‐control and 21 cohort studies involving 80 428 patients were included. The risk of bias was low to moderate. Statin use was associated with a mean AAA growth rate reduction of 0.82 mm/y (95% confidence interval 0.33, 1.32, P=0.001, I²=86%). Statins were also associated with a lower rupture risk (odds ratio 0.63, 95% confidence interval 0.51, 0.78, P<0.0001, I²=27%), and preoperative statin use was associated with a lower 30‐day mortality following elective AAA repair (odds ratio 0.55, 95% confidence interval 0.36, 0.83, P=0.005, I²=57%).

Conclusions

Statin therapy may be associated with reduction in AAA progression, rupture, and lower rates of perioperative mortality following elective AAA repair. These data argue for widespread statin use in AAA patients.

Clinical Trial Registration

URL: http://www.crd.york.ac.uk. Unique identifier: CRD42017056480.

Peripheral artery disease is associated with poor clinical outcome in patients with abdominal aortic aneurysm after endovascular aneurysm repair

BACKGROUND

We investigated the effects of coronary artery disease (CAD) or peripheral artery disease (PAD) on clinical outcomes of patients with abdominal aortic aneurysm (AAA) treated with endovascular aortic aneurysm repair (EVAR).

METHODS

We retrospectively evaluated a total of 475 patients with AAA treated with EVAR at a single center. Patients were divided into three groups: group A (n = 166), patients without CAD or PAD; group B (n = 196), patients with CAD but without PAD; and group C (n = 113), patients with PAD regardless of CAD. The primary endpoint was the accumulated rate of major adverse cardiovascular and cerebrovascular event (MACCE), a composite of all-cause death, myocardial infarction (MI), or stroke.

RESULTS

The prevalence of CAD and PAD in patients with AAA was 55.8 and 23.8%, respectively. Patients were followed for 40.2 ± 35.3 months. Baseline characteristics were similar among the groups except for current smoking (A, 27.4%; B, 20.8%; C, 50.5%; p = 0.001). Three years after EVAR, the incidences of MACCE (A, 5.6%; B, 9.5%; C, 16.7%; p = 0.021) and stroke (A, 0%; B, 2.2%; C, 5.2%; p = 0.025) were highest in group C. All-cause death and aneurysm death did not differ among the groups. PAD [hazard ratio (HR) 2.88, 95% confidence interval (CI) 1.32-6.29, p = 0.008] and previous stroke (HR 4.39, 95% CI 1.94-9.93, p < 0.001) were independent predictors of MACCE.

CONCLUSIONS

PAD was an independent risk factor of increased MACCE and stroke for patients with AAA undergoing EVAR. More intensive secondary prevention may be needed to reduce adverse cardiovascular events in AAA patients with PAD.

Pharmacological treatment of vascular risk factors for reducing mortality and cardiovascular events in patients with abdominal aortic aneurysm

BACKGROUND

Pharmacological prophylaxis has been proven to reduce the risk of cardiovascular events in individuals with atherosclerotic occlusive arterial disease. However, the role of prophylaxis in individuals with abdominal aortic aneurysm (AAA) remains unclear. Several studies have shown that despite successful repair, those people with AAA have a poorer rate of survival than healthy controls. People with AAA have an increased prevalence of coronary heart disease and risk of cardiovascular events. Despite this association, little is known about the effectiveness of pharmacological prophylaxis in reducing cardiovascular risk in people with AAA. This is an update of a Cochrane review first published in 2014.

OBJECTIVES

To determine the long-term effectiveness of antiplatelet, antihypertensive or lipid-lowering medication in reducing mortality and cardiovascular events in people with abdominal aortic aneurysm (AAA).

SEARCH METHODS

For this update the Cochrane Vascular Information Specialist (CIS) searched the Cochrane Vascular Specialised Register (14 April 2016). In addition, the CIS searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2016, Issue 3) and trials registries (14 April 2016) and We also searched the reference lists of relevant articles.

SELECTION CRITERIA

Randomised controlled trials in which people with AAA were randomly allocated to one prophylactic treatment versus another, a different regimen of the same treatment, a placebo, or no treatment were eligible for inclusion in this review. Primary outcomes included all-cause mortality and cardiovascular mortality.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, and completed quality assessment and data extraction. We resolved any disagreements by discussion. Only one study met the inclusion criteria of the review, therefore we were unable to perform meta-analysis.

MAIN RESULTS

No new studies met the inclusion criteria for this update. We included one randomised controlled trial in the review. A subgroup of 227 participants with AAA received either metoprolol (N = 111) or placebo (N = 116). There was no clear evidence that metoprolol reduced all-cause mortality (odds ratio (OR) 0.17, 95% confidence interval (CI) 0.02 to 1.41), cardiovascular death (OR 0.20, 95% CI 0.02 to 1.76), AAA-related death (OR 1.05, 95% CI 0.06 to 16.92) or increased nonfatal cardiovascular events (OR 1.44, 95% CI 0.58 to 3.57) 30 days postoperatively. Furthermore, at six months postoperatively, estimated effects were compatible with benefit and harm for all-cause mortality (OR 0.71, 95% CI 0.26 to 1.95), cardiovascular death (OR 0.73, 95% CI 0.23 to 2.39) and nonfatal cardiovascular events (OR 1.41, 95% CI 0.59 to 3.35). Adverse drug effects were reported for the whole study population and were not available for the subgroup of participants with AAA. We considered the study to be at a generally low risk of bias. We downgraded the quality of the evidence for all outcomes to low. We downgraded the quality of evidence for imprecision as only one study with a small number of participants was available, the number of events was small and the result was consistent with benefit and harm.

AUTHORS' CONCLUSIONS

Due to the limited number of included trials, there is insufficient evidence to draw any conclusions about the effectiveness of cardiovascular prophylaxis in reducing mortality and cardiovascular events in people with AAA. Further good-quality randomised controlled trials that examine many types of prophylaxis with long-term follow-up are required before firm conclusions can be made.

The Vascular Quality Initiative Cardiac Risk Index for prediction of myocardial infarction after vascular surgery

OBJECTIVE

The objective of this study was to develop and to validate the Vascular Quality Initiative (VQI) Cardiac Risk Index (CRI) for prediction of postoperative myocardial infarction (POMI) after vascular surgery.

METHODS

We developed risk models for in-hospital POMI after 88,791 nonemergent operations from the VQI registry, including carotid endarterectomy (CEA; n = 45,340), infrainguinal bypass (INFRA; n = 18,054), suprainguinal bypass (SUPRA; n = 2678), endovascular aneurysm repair (EVAR; n = 18,539), and open abdominal aortic aneurysm repair (OAAA repair; n = 4180). Multivariable logistic regression was used to create an all-procedure and four procedure-specific risk calculators based on the derivation cohort from 2012 to 2014 (N = 61,236). Generalizability of the all-procedure model was evaluated by applying it to each procedure subtype. The models were validated using a cohort (N = 27,555) from January 2015 to February 2016. Model discrimination was measured by area under the receiver operating characteristic curve (AUC), and performance was validated by bootstrapping 5000 iterations. The VQI CRI calculator was made available on the Internet and as a free smart phone app available through QxCalculate.

RESULTS

Overall POMI incidence was 1.6%, with variation by procedure type as follows: CEA, 0.8%; EVAR, 1.0%; INFRA, 2.6%; SUPRA, 3.1%; and OAAA repair, 4.3% (P < .001). Predictors of POMI in the all-procedure model included age, operation type, coronary artery disease, congestive heart failure, diabetes, creatinine concentration >1.8 mg/dL, stress test status, and body mass index (AUC, 0.75; 95% confidence interval [CI], 0.73-0.76). The all-procedure model demonstrated only minimally reduced accuracy when it was applied to each procedure, with the following AUCs: CEA, 0.65 (95% CI, 0.59-0.70); INFRA, 0.69 (95% CI, 0.64-0.73); EVAR, 0.72 (95% CI, 0.65-0.80); SUPRA, 0.62 (95% CI, 0.52-0.72); and OAAA, 0.63 (95% CI, 0.56-0.70). Procedure-specific models had unique predictors and showed improved prediction compared with the all-procedure model, with the following AUCs: CEA, 0.69 (95% CI, 0.66-0.72); INFRA, 0.75 (95% CI, 0.73-0.78); EVAR, 0.76 (95% CI, 0.73-0.80); and OAAA, 0.72 (95% CI, 0.69-0.77). Bias-corrected AUC (95% CI) from internal validation for the models was as follows: all procedures, 0.75 (0.73-0.76); CEA, 0.68 (0.65-0.71); INFRA, 0.74 (0.72-0.76); EVAR, 0.73 (0.70-0.78); and OAAA repair, 0.68 (0.65-0.73).

CONCLUSIONS

The VQI CRI is a useful and valid clinical decision-making tool to predict POMI after vascular surgery. Procedure-specific models improve accuracy when they include unique risk factors.

Does the diameter of abdominal aortic aneurysm influence late survival following abdominal aortic aneurysm repair? A systematic review and meta-analysis

Background

Studies reporting the influence of preoperative abdominal aortic aneurysm diameter on late survival following abdominal aortic aneurysm repair have not been consistent. Aim: To report the influence of abdominal aortic aneurysm diameter on overall long-term survival following abdominal aortic aneurysm repair.

Methods

Embase, Medline and the Cochrane electronic databases were searched to identify articles reporting the influence of abdominal aortic aneurysm diameter on late survival following open aneurysm repair and endovascular aneurysm repair published up to April 2015. Data were extracted from multivariate analysis; estimated risks were expressed as hazard ratio.

Results

A total of 2167 titles/abstracts were retrieved, of which 76 studies were fully assessed; 19 studies reporting on 22,104 patients were included. Preoperative larger abdominal aortic aneurysm size was associated with a worse survival compared to smaller aneurysms with a pooled hazard ratio of 1.14 (95% CI: 1.09–1.18), per 1 cm increase in abdominal aortic aneurysm diameter. Subgroup analysis of the different types of repair was performed and the hazard ratio (95% CI), for open aneurysm repair and endovascular aneurysm repair were 1.08 (1.03–1.12) and 1.20 (1.15–1.25), respectively, per 1 cm increase. There was a significant difference between the groups p < 0.02.

Conclusions

This meta-analysis suggests that preoperative large abdominal aortic aneurysm independently influences overall late survival following abdominal aortic aneurysm repair, and this association was greater in abdominal aortic aneurysm repaired with endovascular aneurysm repair.

Validity of the Postoperative Morbidity Survey after abdominal aortic aneurysm repair-a prospective observational study

BACKGROUND

Currently, there is no standardised tool used to capture morbidity following abdominal aortic aneurysm (AAA) repair. The aim of this prospective observational study was to validate the Postoperative Morbidity Survey (POMS) according to its two guiding principles: to only capture morbidity substantial enough to delay discharge from hospital and to be a rapid, simple screening tool.

METHODS

A total of 64 adult patients undergoing elective infrarenal AAA repair participated in the study. Following surgery, the POMS was recorded daily, by trained research staff with the clinical teams blinded, until hospital discharge or death. We modelled the data using Cox regression, accounting for the competing risk of death, with POMS as a binary time-dependent (repeated measures) internal covariate. For each day for each patient, 'discharged' (yes/no) was the event, with the elapsed number of days post-surgery as the time variable. We derived the hazard ratio for any POMS morbidity (score 1-9) vs. no morbidity (zero), adjusted for type of repair (endovascular versus open), age and aneurysm size.

RESULTS

The hazard ratio for alive discharge with any POMS-recorded morbidity versus no morbidity was 0.130 (95 % confidence interval 0.070 to 0.243). The median time-to-discharge was 13 days after recording any POMS morbidity vs. 2 days after scoring zero for POMS morbidity. Compliance with POMS completion was 99.5 %.

CONCLUSIONS

The POMS is a valid tool for capturing short-term postoperative morbidity following elective infrarenal AAA repair that is substantial enough to delay discharge from hospital. Daily POMS measurement is recommended to fully capture morbidity and allow robust analysis. The survey could be a valuable outcome measure for use in quality improvement programmes and future research.

Proposed research plan for the derivation of a new Cardiac Risk Index

The Revised Cardiac Risk Index (RCRI) was incorporated into the American College of Cardiology/American Heart Association (ACC/AHA) recommendations for the preoperative evaluation of the cardiac patient for noncardiac surgery. The purpose of this review was to analyze studies on cardiovascular clinical risk prediction that had used the previous "standard best" model, the RCRI, as a comparator. This review aims to determine whether modification of the current risk factors or adoption of other risk factors or other risk indices would improve upon the discrimination of cardiac risk prediction when compared with the RCRI. This is necessary because recent risk prediction models have shown better discrimination for major adverse cardiac events, and the pre-eminence of the RCRI is now in question. There is now a need for a new "best standard" cardiovascular risk prediction model to supersede the RCRI. This is desirable because it would: (1) allow for a global standard of cardiovascular risk assessment; (2) provide a standard comparator in all risk prediction research; (3) result in comparable data collection; and (4) allow for individual patient data meta-analyses. This should lead to continued progress in cardiovascular clinical risk prediction. A review of the current evidence suggests that to improve the preoperative clinical risk stratification for adverse cardiac events, a new risk stratification model be built that maintains the clinical risk factors identified in the RCRI, with the following modifications: (1) additional glomerular filtration rate cut points (as opposed to a single creatinine cut point); (2) age; (3) a history of peripheral vascular disease; (4) functional capacity; and (5) a specific surgical procedural category. One would expect a substantial improvement in the discrimination of the RCRI with this approach. Although most noncardiac surgeries will benefit from a standard "generic" cardiovascular risk prediction model, there are data to suggest that patients with human immunodeficiency virus disease who are undergoing vascular surgery may benefit from specific cardiovascular risk prediction models.

The impact of abdominal aortic aneurysm on muscle mass and energy expenditure: A novel preliminary investigation

OBJECTIVE

Vascular surgical patients, including those with abdominal aortic aneurysm (AAA), are nutritionally vulnerable. The aim of this study was to compare resting energy expenditure (REE) of patients with AAA relative to age- and gender-matched controls and explore relationships between aneurysm size and muscle mass.

METHODS

Twenty patients with AAA underwent assessment of REE using indirect calorimetry. Mid-arm circumference and triceps skinfold thickness were measured and corrected arm muscle area calculated. Twenty gender- and age-matched controls were assessed using the same procedures.

RESULTS

Mean (SD) age of participants with AAA was 74.7 (7.7) years, size of AAA ranged from 45 to 70 mm. Median (IQR) REE was significantly higher than controls [5990 (5469, 7017) kJ/day versus 5086 (4536, 5886) kJ/day, p = .011; or 69 (64, 80) kJ/kg/day versus 66 (61, 69) kJ/kg/day, p = .046]. While weight-adjusted REE was independent of aneurysm size (r = .200; p = .397), as aneurysm size increased, weight-adjusted corrected arm muscle area decreased (r = -.576; p = .008).

CONCLUSION

The raised REE and decline in muscle mass associated with larger AAA suggest that early detection and attention to nutritional requirements of patients with AAA may be warranted.

Pharmacological treatment of vascular risk factors for reducing mortality and cardiovascular events in patients with abdominal aortic aneurysm

BACKGROUND

Pharmacological prophylaxis has been proven to reduce the risk of cardiovascular events in patients with atherosclerotic occlusive arterial disease. However, the role of prophylaxis in patients with abdominal aortic aneurysm (AAA) remains unclear. Several studies have shown that despite successful repair, those with AAA have a poorer rate of survival than healthy controls. People with AAA have an increased prevalence of coronary heart disease and risk of cardiovascular events. Despite this association, little is known about the effectiveness of pharmacological prophylaxis in reducing cardiovascular risk in people with AAA.

OBJECTIVES

To determine the long-term effectiveness of antiplatelet, antihypertensive or lipid-lowering medication in reducing mortality and cardiovascular events in people with abdominal aortic aneurysm (AAA).

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched April 2013) and CENTRAL (2013, Issue 3). Reference lists of relevant articles were also checked.

SELECTION CRITERIA

Randomised controlled trials in which people with AAA were randomly allocated to one prophylactic treatment versus another, a different regimen of the same treatment, a placebo, or no treatment were eligible for inclusion in this review. Primary outcomes included all-cause mortality and cardiovascular mortality.

DATA COLLECTION AND ANALYSIS

Selection of the studies, quality assessment and data extraction were completed independently by two review authors. Any disagreements were resolved by discussion. Only one study was included in the review, therefore meta-analysis could not be performed.

MAIN RESULTS

One randomised controlled study was included in the review. A subgroup of 227 patients with AAA received either metoprolol (N = 111) or placebo (N = 116). There was no clear evidence that metoprolol reduced all-cause mortality (odds ratio (OR) 0.17, 95% confidence interval (CI) 0.02 to 1.41), cardiovascular death (OR 0.20, 95% CI 0.02 to 1.76), AAA-related death (OR 1.05, 95% CI 0.06 to 16.92) or increased nonfatal cardiovascular events (OR 1.44, 95% CI 0.58 to 3.57) 30 days postoperatively. Furthermore, at six months postoperatively, estimated effects were compatible with benefit and harm for all-cause mortality (OR 0.71, 95% CI 0.26 to 1.95), cardiovascular death (OR 0.73, 95% CI 0.23 to 2.39) and nonfatal cardiovascular events (OR 1.41, 95% CI 0.59 to 3.35). Adverse drug effects were reported for the whole study population and were not available for the subgroup of participants with AAA. The study was deemed to be at a generally low risk of bias.

AUTHORS' CONCLUSIONS

Due to the limited number of trials, there is insufficient evidence to draw any conclusions about the effectiveness of cardiovascular prophylaxis in reducing mortality and cardiovascular events in people with AAA. Further good-quality randomised controlled trials examining many types of prophylaxis with long-term follow-up are required before firm conclusions can be made.

Extracorporeal membrane oxygenation support for abdominal aortic aneurysms surgery in high-risk patients

Surgical treatment of an abdominal aortic aneurysm in patients with a heart disease is risky. Aortic cross-clamping is featured by important consequences on cardiac, renal and gastrointestinal functions. Endovascular aortic repair is considered to be the gold standard in patients with severe comorbidities. However, in the case of unsuccessful endovascular treatment, surgery can be reconsidered with the use of extracorporeal membrane oxygenation, which seems to be a new tool for the management of cardiac and gastrointestinal events ensuring better post-operative outcomes.

Meta-analysis of postoperative mortality after elective repair of abdominal aortic aneurysms detected by screening

Background

The aim of this study was to compare the mortality rate within 30 days of elective surgery for abdominal aortic aneurysm (AAA) in men randomized to an invitation for ultrasound screening with that of men in the control group, whose aneurysms were detected incidentally.

Methods

Relevant reports from randomized trials of screening were identified through a systematic search of MEDLINE. Four relevant trials were identified, and supplemented with data from the Viborg Vascular screening trial. Data were updated in two studies. Meta-analysis was undertaken with effects calculated as a fixed odds ratio (OR) with 95 per cent confidence interval. Heterogeneity between the studies was assessed by the χ2 test.

Results

There were 25 deaths (2·9 per cent) following elective surgery in 858 men invited for screening compared with 21 (5·5 per cent) of 383 in the control group (OR 0·49, 0·27 to 0·88). There were 18 deaths (2·4 per cent) following elective surgery for 747 screen-detected AAAs compared with 28 (6·1 per cent) following elective repair of 459 incidentally detected aneurysms (OR 0·37, 0·20 to 0·68).

Conclusion

The offer of screening identifies men whose early survival following elective AAA repair is better than that of men with an AAA detected incidentally.

Thrombus volume is associated with cardiovascular events and aneurysm growth in patients who have abdominal aortic aneurysms

BACKGROUND

Patients with abdominal aortic aneurysms (AAA) are predisposed to cardiovascular events and often experience continual expansion of their aneurysm. Cardiovascular events and expansion rates are positively correlated with aneurysm size. AAA is usually associated with intraluminal thrombus, which has previously been implicated in AAA pathogenesis. This study prospectively assessed the association of infrarenal abdominal aortic thrombus volume with cardiovascular events and AAA growth.

METHODS

Ninety-eight patients with AAAs underwent computed tomography angiography (CTA). The volume of infrarenal aorta thrombus was measured by a previously validated technique. Patients were monitored prospectively for a median of 3 years (interquartile range [IQR], 2.0-3.6 years), and cardiovascular events (nonfatal stroke, nonfatal myocardial infarction, coronary revascularization, amputation, and cardiovascular death) were recorded. Of the original patients, 39 underwent repeat CTA a median of 1.5 years (IQR, 1.1-3.3 years) after entry to the study. Kaplan-Meier and Cox proportional analysis were used to examine the association of aortic thrombus with cardiovascular events and average weighted AAA growth.

RESULTS

There were 28 cardiovascular events during follow-up. The incidence of cardiovascular events was 23.4% and 49.2% for patients with small (smaller than the median) and large (median or larger) volumes of aortic thrombus, respectively, at 4 years (P = .040). AAA thrombus volume of median or larger was associated with increased cardiovascular events (relative risk [RR] 2.8, 95% confidence interval [CI], 1.01-5.24) independent of other risk factors, including initial AAA diameter, but was only of borderline significance when patients were censored at the time of AAA repair (RR, 2.35; 95% CI, 0.98-5.63). In the subset of patients with CTA follow-up, the median annual increase in AAA volume was 5.1 cm³ (IQR, 0.8-10.3 cm³). Annual AAA volume increase was positively correlated with initial AAA diameter (r = 0.44, P = .006) and thrombus volume (r = 0.50, P = .001). Median or larger aortic thrombus volume was associated with rapid AAA volume increase (≥ 5 cm/y), independent of initial aortic diameter (RR, 15.0; 95% CI, 1.9-115.7; P = .009).

CONCLUSION

In this small cohort, infrarenal aortic thrombus volume was associated with the incidence of cardiovascular events and AAA progression. These results need to be confirmed and mechanisms underlying the associations clarified in large further studies.

The Influence of Diabetes on Degree of Abdominal Aortic Aneurysm Tissue Inflammation

Abdominal aortic aneurysm (AAA) progression and disease resistance are related to transmural degenerative processes and an inflammatory infiltration (INF). Diabetes is associated with low prevalence and growth rate of AAA. We sought to characterize INF in established AAA (INFAAA), in diabetic patients. From 89 male patients aged 52 to 83 years, aneurysm specimens obtained at open asymptomatic nonruptured AAA repair were graded for INF and immunostained using antibodies against T-lymphocytes (CD3) and macrophages (CD68). Diabetic patients had an odds ratio (OR) 3.8, 95% confidence interval ([CI] 1.14-12.96), P = .03, of experiencing above-median INFAAA. These associations were affected by serum glucose (SG) levels (OR 3.6, 95% CI [0.72-18.77]; P = .1). Macrophage subpopulations higher in diabetic patients (1.44 ± 0.78 versus 0.98 ± 0.76; P = .02) were correlated with SG (r = .21, P = .044). Abdominal aortic aneurysms in diabetic patients are associated with higher INF. Macrophage densities are correlated with SG.

Are Statins an Option in the Management of Abdominal Aortic Aneurysms?

Medline was searched for studies investigating the perioperative and long-term results that derive from statin use in patients with abdominal aortic aneurysm and the clinical and experimental evidence dealing with aneurysm expansion. Data suggest that statins improve the perioperative and long-term outcomes of aneurysm operations and may also reduce expansion rates. International guidelines recommend the use of statins in these patients because abdominal aortic aneurysms are considered as a coronary heart disease equivalent. These guidelines do not appear to have been widely implemented. Preliminary results suggest that statins might play a role in the management of abdominal aortic aneurysms. Verification of these results in large-scale trials may hold implications for a more comprehensive approach of patients with abdominal aortic aneurysms as well as population-wide aneurysm screening programs. Irrespective of the role of statins on aneurysm expansion rates, it is important to ensure that all abdominal aortic aneurysm patients receive statin therapy to improve perioperative and long-term morbidity and mortality.

Anemia is associated with abdominal aortic aneurysm (AAA) size and decreased long-term survival after endovascular AAA repair

OBJECTIVE

Anemia is a common comorbid condition in various inflammatory states and an established predictor of mortality in patients with chronic heart failure, ischemic heart disease, and end-stage renal disease. The present study of patients with abdominal aortic aneurysm (AAA) undergoing endovascular repair (EVAR) assessed the relationships between baseline hemoglobin concentration and AAA size, as well as anemia and long-term survival.

METHODS

Between March 1994 and November 2006, 711 patients (65 women, mean age 75.8 +/- 7.8 years) underwent elective EVAR. Anemia was defined as a hemoglobin level <13 g/dL in men and <12 g/dL in women. Post-EVAR mean follow-up was 48.3 +/- 32.0 months. Association of hemoglobin level with AAA size was assessed with multiple linear regression. Mortality was determined with use of the internet-based Social Security Death Index and the electronic hospital record. Kaplan-Meier survival curves of anemic and nonanemic patient groups were compared by the log-rank method. Multivariable logistic regression models were used to determine the influence of anemia on vital status after EVAR.

RESULTS

A total of 218/711 (30.7%) of AAA patients undergoing EVAR had anemia at baseline. After adjustment for various risk factors, hemoglobin level was inversely related to maximum AAA diameter (beta: - .144, 95%-CI: -1.482 - .322, P = .002). Post-EVAR survival was 65.5% at 5 years and 44.4% at 10 years. In long-term follow-up, survival was significantly lower in patients with anemia as compared to patients without anemia (P < .0001 by log-rank). Baseline hemoglobin levels were independently related to long-term mortality in multivariable Cox regression analysis adjusted for various risk factors (adjusted HR: 0.866, 95% CI: .783 to .958, P = .005). Within this model, statin use (adjusted HR: .517, 95% CI: .308 to .868, P = .013) was independently related to long-term survival, whereas baseline AAA diameter (adjusted HR: 1.022, 95% CI: 1.009 to 1.036, P = .001) was an independently associated with increased mortality.

CONCLUSIONS

Baseline hemoglobin concentration is independently associated with AAA size and reduced long-term survival following EVAR. Thus, the presence or absence of anemia offers a potential refinement of existing risk stratification instruments.

Glomerular filtration rate after left renal vein division and reconstruction during infrarenal aortic aneurysm repair

OBJECTIVES

The study assessed the effect on postoperative renal function of left renal vein (LRV) division and reconstruction by direct reanastomosis or graft interposition during infrarenal abdominal aortic aneurysm (AAA) repair.

METHODS

Between January 2001 and March 2006, 1189 patients underwent elective open repair of infrarenal AAAs. LRV division was performed in 15 (1.3%) and its reconstruction in all but one (LRV group), where the LRV was occluded. Patients' glomerular filtration rates (GFRs) were retrospectively estimated through postoperative day 4 by using the Cockcroft-Gault equation and compared with the GFRs of 56 controls undergoing AAA repair without LRV division (control group) randomly identified from a prospectively compiled database in a 4:1 ratio. Post hoc 1:1 case-matched analysis was also performed. Statistical analyses were performed as appropriate.

RESULTS

Comparison of demographics and risk factors revealed no statistically significant differences between the two groups with the exception of the following: AAAs were larger in LRV group (71.4 +/- 17.1 mm vs 56.0 +/- 14.6 mm; P = .003) and preoperative GFR was lower in LRV group (65.3 +/- 19.0 mL/min/1.73 m(2) vs 82.8 +/- 22.3 mL/min/1.73 m(2); P = .009). Postoperatively, the trend of GFR with time did not differ between groups (P = .33). The variation of GFR at day 4 after surgery compared with preoperative values was not different either (5.6 +/- 12.6 mL/min/1.73 m(2) vs 1.0 +/- 15.5 mL/min/1.73 m(2); P = .67). A further 1:1 case-matched multivariate analysis of variance, matching patients and controls by AAA size and preoperative GFR, showed no difference in trend of GFR with time between groups (P = .15). Operative time was not significantly longer in LRV group (148.4 +/- 35.8 minutes vs 131.0 +/- 40.3 minutes; P = .07). No differences between groups were found for blood loss (585.7 +/- 264.2 mL vs 567.7 +/- 222.5 mL; P = .88), perioperative complications (5 vs 8; P = .12), or hospital length of stay (6.2 +/- 1.8 days vs 5.5 +/- 1.2 days; P = .10). A 6-month follow-up of renal function available in 12 patients of LRV group showed no significant decrease in GFR compared with postoperative values (70.8 +/- 24.8 mL/min/1.73 m(2) vs 69.1 +/- 23.5 mL/min/1.73 m(2); P = .86). At duplex scan, the reconstructed LRV could be insonated in nine of these 12 patients and all were patent.

CONCLUSIONS

LRV division during AAA repair was associated with larger aneurysms and preoperative subclinical renal function impairment. In these patients, LRV reconstruction was associated with the maintenance of preoperative renal functional status without significantly lengthening of operative time or increasing the complications from surgery.