Editor's Choice – Effect of Statins on Total Mortality in Abdominal Aortic Aneurysm Repair: A Systematic Review and Meta-analysis

Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms

OBJECTIVE

The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy.

METHODS

The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence.

RESULTS

A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed.

CONCLUSION

The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.

Persistent High Long-term Excess Mortality After Elective AAA Repair Especially in Women: A Large Population-based Study

OBJECTIVE

The aim of this time-trend analysis is to estimate long-term excess mortality and associated cardiovascular risk for abdominal aortic aneurysm (AAA) patients after elective repair while addressing the changes in AAA management and patient selection over time.

BACKGROUND

Despite the intensification of endovascular aneurysm repair and cardiovascular risk management, Swedish population data suggest that AAA patients retain a persistently high long-term mortality after elective repair. The question is whether this reflects suboptimal treatment, a changing patient population over time, or a national phenomenon.

METHODS

Nationwide time-trend analysis including 40,730 patients (87% men) following elective AAA repair between 1995 and 2017. Three timeframes were compared, each reflecting changes in the use of endovascular aneurysm repair and intensification of cardiovascular risk management. Relative survival analyses were used to estimate disease-specific excess mortality. Competing risk of death analysis evaluated the risk of cardiovascular versus noncardiovascular death. Sensitivity analysis evaluated the impact of changes in patient selection over time.

RESULTS

Short-term excess mortality significantly improved over time. Long-term excess mortality remained high with a doubled mortality risk for women (relative excess risk=1.87, 95% CI: 1.73-2.02). Excess mortality did not differ between age categories. The risk of cardiovascular versus noncardiovascular death remained similar over time, with a higher risk of cardiovascular death for women. Changes in patient population (ie, older and more comorbid patients in the latter period) marginally impacted excess mortality (2%).

CONCLUSIONS

Despite changes in AAA care, patients retain a high long-term excess mortality after elective repair with a persistent high cardiovascular mortality risk. In this, a clear sex - but no age - disparity stands out.

Using red blood cell distribution width to predict death after abdominal aortic aneurysm rupture

BACKGROUND

An abdominal aortic aneurysm is a life-threatening enlargement in the major vessel at the abdomen level. This study investigated the associations between different levels of red blood cell distribution width and all-cause mortality among patients with abdominal aortic aneurysm rupture. It developed predictive models for all-cause mortality risk.

METHODS

This was a retrospective cohort study using 2001 to 2012 MIMIC-III dataset. The study sample included 392 U.S. adults with abdominal aortic aneurysms who were admitted to ICU after the aneurysm rupture. Then we used two single-factor and four multivariable logistic regression models to examine the associations between different levels of red blood cell distribution and all-cause mortality (30 days and 90 days), controlling for demographics, comorbidities, vital signs, and other laboratory measurements. The receiver operator characteristic curves were calculated, and the areas under the curves were recorded.

RESULTS

There were 140 (35.7%) patients with an abdominal aortic aneurysm in the red blood cell distribution width range between 11.7 and 13.8%, 117 (29.8%) patients in the range between 13.9 and 14.9%, and 135 (34.5%) patients in the range between 15.0 and 21.6%. Patients with higher red blood cell distribution width level (> 13.8%) tended to have a higher mortality rate (both 30 days and 90 days), congestive heart failure, renal failure, coagulation disorders, lower hemoglobin, hematocrit, MCV, red blood cell count, higher levels of chloride, creatinine, sodium, and BUN (All P < 0.05). Results of multivariate logistic regression models indicated that patients with higher red blood cell distribution width levels (> 13.8%) had the highest statistically significant odd ratios of 30 days and 90 days of all-cause mortality than lower red blood cell distribution width levels. The area under the RDW curve was lower (P = 0.0009) than that of SAPSII scores.

CONCLUSIONS

Our study found that patients with abdominal aortic aneurysm rupture with a higher blood cell distribution had the highest risk of all-cause mortality. Using the blood cell distribution width level in patients with abdominal aortic aneurysm rupture to predict mortality should be considered in future clinical practice.

Temporal trends in abdominal aortic aneurysmal disease: a nationwide cohort study on cardiovascular morbidity and medical cardioprotective therapy

Aims

Abdominal aortic aneurysmal disease is associated with increased risk of cardiovascular morbidity and death, which potentially can be reduced with cardioprotective medical therapy. The aim of this study was to observe temporal trends in prevalence and incidence of cardiovascular comorbidity as well as use of medical cardioprotective treatment in patients diagnosed with abdominal aortic aneurysmal disease.

Methods and results

This was a population-based cohort study based on data from national health registries, including all patients diagnosed with abdominal aortic aneurysms between 1998 and 2018. Data were stratified into four time periods (1999–2003, 2004–2008, 2009–2013, and 2014–2018) to illustrate trends over time. Outcome measures were (i) cardiovascular comorbidity and medical cardioprotective therapy at time of diagnosis, (ii) new admissions for atherosclerotic cardiovascular disease, and (iii) all-cause mortality after 2-year follow-up. The study cohort included 33 296 individuals. Mean age was 74 years. Prevalence of atherosclerotic cardiovascular comorbidity at diagnosis decreased from 41.5 to 32.6%. Use of statins increased from 17.9 to 66.9%, antiplatelets from 45.6 to 63.3%, and combined therapy with both antiplatelets and statins from 11.3 to 44.8%, and from 12.1 to 50.7% when anticoagulant therapy was included. Developments in medication use plateaued after 2013. Prevalence and incidence of atherosclerotic cardiovascular disease decreased through all four time periods. The same applied to all-cause mortality, which decreased from 24.3 to 12.4 deaths (per 100 person-years).

Conclusion

In patients diagnosed with abdominal aortic aneurysm, cardiovascular comorbidity at diagnosis, risk of future cardiovascular events, and all-cause mortality is decreasing. Nevertheless, cardiovascular burden and mortality rates remain substantial, and medical cardioprotective therapy can be further improved.

An assessment of the current medical management of thoracic aortic disease: A patient-centered scoping literature review

Thoracic aortic aneurysm and dissection are complex diagnoses that require management by multidisciplinary providers using a variety of medical therapies, surgical interventions, and lifestyle modifications. Pharmacological agents, such as β-blockers (atenolol) and angiotensin II type 1 receptor blockers (losartan), have been mainstay treatments for several years, and research from the past decade has continued to evaluate these and other medication classes to further improve patient morbidity and mortality. Combination β- and renin-aldosterone-angiotensin blockade, statins, metformin, antioxidants, and vitamins have been evaluated as therapeutics in both thoracic and abdominal aortic aneurysms, as well as the effects of various antibiotics (ie, fluoroquinolones and tetracyclines) and benefits of lifestyle modifications (eg, diet and exercise) and enhanced patient-centered care and treatment adherence. In addition, as our understanding of the genetic, biochemical, and pathophysiological mechanisms behind these diseases expands, so do potential targets for future therapeutic research (eg, interleukins, matrix metalloproteases, and mast cells). This review incorporates the major meta-analyses, systematic and generalized reviews, and clinical trials published from 2010 through 2021 that focus on these topics in thoracic aortic aneurysms (and abdominal aneurysms when thoracic literature is scarce). Several key ongoing clinical trials, case studies, and in vivo/in vitro studies are also mentioned. Furthermore, we discuss current gaps in the literature and the abundance of clinical evidence for some interventions in abdominal aneurysms with few thoracic correlates, thus indicating a need for investigation of these subjects in the latter.

Five-year survival after elective open and endovascular aortic aneurysm repair

BACKGROUND AND OBJECTIVE

Current evidence suggests short-term survival benefit from endovascular aneurysm repair (EVAR) versus open surgical repair (OSR) in elective abdominal aortic aneurysm (AAA) procedures, but this benefit is lost during long-term follow-up. The aim of this study was to compare short- and mid-term all-cause mortality in patients with non-ruptured aneurysm treated by OSR and EVAR; and to assess the rate of complications and reinterventions, as well as to evaluate their impact on survival.

METHODS

The medical records of the non-ruptured AAA patients undergoing OSR or EVAR between 1 January 2011 and 31 December 2019 at Tartu University Hospital, Estonia, were retrospectively reviewed. We gathered survival data from the national registry (mean follow-up period was 3.7 ± 2.3 years).

RESULTS

A total of 225 non-ruptured AAA patients were treated operatively out of whom 95 (42.2%) were EVAR and 130 (57.8%) were OSR procedures. The difference in estimated all-cause mortality between the OSR and EVAR groups at day 30 was statistically irrelevant (2.3% vs 0%; p = 0.140), but OSR patients showed statistically significantly higher 5 year survival compared with EVAR patients (75.3% vs 50.0%, p = 0.002). Complication and reintervention rates for the EVAR and OSR groups did not differ statistically (26.3% vs 16.9%, p = 0.122; 10.5% vs 11.5%, p = 0.981, respectively). Multivariate analysis revealed that greater aneurysm diameter (p = 0.012), EVAR procedure (p = 0.016), male gender (p = 0.023), and cerebrovascular diseases (p = 0.028) were independently positively associated with 5-year mortality.

CONCLUSIONS

Thirty-day mortality, and complication and reintervention rates for EVAR and OSR after elective AAA repair were similar. Although the EVAR procedure is an independent risk factor for 5-year mortality, higher age and greater proportion of comorbidities among EVAR patients may influence not only the choice of treatment modality, but also prognosis.

No Effect of Hypercholesterolemia on Elastase-Induced Experimental Abdominal Aortic Aneurysm Progression

OBJECTIVE

Epidemiological studies link hyperlipidemia with increased risk for abdominal aortic aneurysms (AAAs). However, the influence of lipid-lowering drugs statins on prevalence and progression of clinical and experimental AAAs varies between reports, engendering controversy on the association of hyperlipidemia with AAA disease. This study investigated the impact of hypercholesterolemia on elastase-induced experimental AAAs in mice.

METHODS

Both spontaneous (targeted deletion of apolipoprotein E) and induced mouse hypercholesterolemia models were employed. In male wild type (WT) C57BL/6J mice, hypercholesterolemia was induced via intraperitoneal injection of an adeno-associated virus (AAV) encoding a gain-of-function proprotein convertase subtilisin/kexin type 9 mutation (PCSK9) followed by the administration of a high-fat diet (HFD) (PCSK9+HFD) for two weeks. As normocholesterolemic controls for PCSK9+HFD mice, WT mice were infected with PCSK9 AAV and fed normal chow, or injected with phosphate-buffered saline alone and fed HFD chow. AAAs were induced in all mice by intra-aortic infusion of porcine pancreatic elastase and assessed by ultrasonography and histopathology.

RESULTS

In spontaneous hyper- and normo-cholesterolemic male mice, the aortic diameter enlarged at a constant rate from day 3 through day 14 following elastase infusion. AAAs, defined as a more than 50% diameter increase over baseline measurements, formed in all mice. AAA progression was more pronounced in male mice, with or without spontaneous hyperlipidemia. The extent of elastin degradation and smooth muscle cell depletion were similar in spontaneous hyper- (score 3.5 for elastin and 4.0 for smooth muscle) and normo- (both scores 4.0) cholesterolemic male mice. Aortic mural macrophage accumulation was also equivalent between the two groups. No differences were observed in aortic accumulation of CD4+ or CD8+ T cells, B cells, or mural angiogenesis between male spontaneous hyper- and normocholesterolemic mice. Similarly, no influence of spontaneous hypercholesterolemia on characteristic aneurysmal histopathology was noted in female mice. In confirmatory experiments, induced hypercholesterolemia also exerted no appreciable effect on AAA progression and histopathologies.

CONCLUSION

This study demonstrated no recognizable impact of hypercholesterolemia on elastase-induced experimental AAA progression in both spontaneous and induced hypercholesterolemia mouse models. These results add further uncertainty to the controversy surrounding the efficacy of statin therapy in clinical AAA disease.

The Potential Benefits and Costs of an Intensified Approach to Low Density Lipoprotein Cholesterol Lowering in People with Abdominal Aortic Aneurysm

OBJECTIVE

The aims of this study were to assess the incidence of major vascular events (MVE) and peripheral vascular events (PVE) in people with a small asymptomatic abdominal aortic aneurysm (AAA) and model the theoretical benefits and costs of an intensified low density lipoprotein cholesterol (LDL-C) lowering programme.

METHODS

A total of 583 participants with AAAs measuring 30 - 54 mm were included in this study. The control of LDL-C and prescription of lipid lowering drugs were assessed by dividing participants into approximately equal tertiles depending on their year of recruitment into the study. The occurrence of MVE (myocardial infarction, stroke, cardiovascular death, and coronary or non-coronary revascularisation) and PVE (non-coronary revascularisation, AAA repair, and major amputation) were recorded prospectively, and the incidence of these events was calculated using Kaplan-Meier analysis. The relative risk reduction reported for these events in a previous randomised control trial (RCT) was then applied to these figures to model the absolute risk reduction and numbers needed to treat (NTT) that could theoretically be achieved with a mean LDL-C lowering of 1 mmol/L. The maximum allowable expense for a cost effective intensive LDL-C lowering programme was estimated using a cost utility analysis.

RESULTS

At entry, only 28.5% of participants had an LDL-C of < 1.8 mmol/L and only 18.5% were prescribed a high potency statin (atorvastatin 80 mg or rosuvastatin 40 mg). The five year incidences of MVE and PVE were 38.1% and 44.7%, respectively. It was estimated that if the mean LDL-C of the cohort had been reduced by 1 mmol/L, this could have reduced the absolute risk of MVE and PVE by 6.5% (95% CI 4.4 - 8.7; NNT 15) and 5.3% (95% CI 1.4 - 7.5; NNT 19), respectively. It was estimated that the maximum allowable expense for a cost effective LDL-C lowering programme would be between $1 239 AUD (€768) and $1 582 AUD (€981) per person per annum over a five year period.

CONCLUSION

People with a small asymptomatic AAA are at high risk of MVE and PVE. This study provides evidence of the possible benefits and allowable expense for a cost effective intensive LDL-C lowering programme in this population.

Metabolomic Profile of Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is characterized by structural deterioration of the aortic wall, leading to aortic dilation and rupture. The aim was to compare 183 low molecular weight metabolites in AAA patients and aorta-healthy controls and to explore if low molecular weight metabolites are linked to AAA growth. Blood samples were collected from male AAA patients with fast (mean 3.3 mm/year; range 1.3-9.4 mm/year; n = 39) and slow growth (0.2 mm/year; range -2.6-1.1 mm/year; n = 40), and from controls with non-aneurysmal aortas (n = 79). Targeted analysis of 183 metabolites in plasma was performed with AbsoluteIDQ p180 kit. The samples were measured on a QTRAP 4500 coupled to an Agilent 1260 series HPLC. The levels of only four amino acids (histidine, asparagine, leucine, isoleucine) and four phosphatidylcholines (PC.ae.C34.3, PC.aa.C34.2, PC.ae.C38.0, lysoPC.a.C18.2) were found to be significantly lower (p < 0.05) after adjustment for confounders among the AAA patients compared with the controls. There were no differences in the metabolites distinguishing the AAA patients with slow or fast growth from the controls, or distinguishing the patients with slow growth from those with fast growth. The current study describes novel significant alterations in amino acids and phosphatidylcholines metabolism associated with AAA occurrence, but no associations were found with AAA growth rate.

Peripheral Artery Disease and Abdominal Aortic Aneurysm: The Forgotten Diseases in COVID-19 Pandemic. Results from an Observational Study on Real-World Management

Background and Objectives: It is well established that patients with peripheral artery disease (PAD) as well abdominal aortic aneurysm (AAA) have an increased cardiovascular (CV) mortality. Despite this higher risk, PAD and AAA patients are often suboptimality treated. This study assessed the CV profile of PAD and AAA patients, quantifying the survival benefits of target-based risk-factors modification even in light of the COVID-19 pandemic. Materials and Methods: PAD and AAA patients admitted for any reason to the Vascular Unit from January 2019 to February 2020 were retrospectively analyzed. Biochemical and CV profiles as well as ongoing medical therapies were recorded. Benefits of CV risk-factors control were estimated using the SMART-REACH model. A follow-up visit during the year 2020 was scheduled. Results: A total of 669 patients were included. Of these, 190 showed AAA and 479 PAD at any stage. Only 54% of PAD and 41% of AAA patients were on lipid-lowering drugs with non-optimal low-density lipoprotein (LDL) levels for most of them. A better control of all modifiable CV risk-factors based on the current guidelines would offer an absolute risk reduction of the mean 10-year CV risk by 9% in PAD and 14% in AAA. Unfortunately, the follow-up visit was lost because of COVID-19 limitations. Conclusions: Lipid profiles of PAD and AAA patients were far from guideline-based targets, and medical management was suboptimal. In our center, the COVID-19 pandemic impacted on the strict surveillance required in these very high-risk patients. The achievement of guideline-based therapeutic targets would definitively confer additional significant benefits in reducing the CV risk in these patients.

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.

Preoperative statin therapy is associated with higher 5-year survival after thoracic endovascular aortic repair

OBJECTIVE

Statin use is associated with higher long-term survival after abdominal aortic aneurysm repair. However, the association between statin use and survival after thoracic endovascular aortic repair (TEVAR) has not been established.

METHODS

We performed a review of prospectively collected data of all patients who had undergone TEVAR in the Vascular Quality Initiative between 2014 and 2020. We excluded patients aged <18 years, those who had presented with trauma, and those who had received custom-manufactured or physician-modified devices. We evaluated the association between preoperative statin therapy and in-hospital mortality and complications and 5-year mortality. We also analyzed the trend of preoperative statin use in elective cases for the previous 7 years. To account for nonrandom assignment to treatment, we used propensity score matching of patient characteristics, comorbidities, pathology, and urgency for preoperative statin use. We used logistic regression and Cox regression for the short-term and 5-year outcomes, respectively.

RESULTS

Of 6266 patients who had undergone TEVAR and met the inclusion criteria, 3331 (53%) patients had been taking a statin preoperatively, including 1148 of 2267 (64%) treated for aneurysmal disease. After propensity score matching, 1875 patients were in each cohort. Preoperative statin use was associated with lower rates of any perioperative complication (16.7% vs 19.6%; odds ratio, 0.82; 95% confidence interval [CI] 0.69-0.97; P = .022). Overall, preoperative statin use was also associated with lower 5-year mortality (18.8% vs 24.5%; hazard ratio [HR], 0.74; 95% CI, 0.63-0.89; P = .001). When stratified by urgency, preoperative statin use was associated with lower 5-year mortality after elective TEVAR (14.9% vs 22.4%; HR, 0.62; 95% CI, 0.49-0.79; P < .001) but not after urgent or emergent TEVAR (27.4% vs 29.1%; HR, 0.89; 95% CI, 0.70-1.14; P = .37). When stratified by pathology, preoperative statin use was associated with significantly lower 5-year mortality for patients with aneurysms (HR, 0.63; 95% CI, 0.48-0.83; P = .001). Although the mortality was also lower for patients with dissection and "other" pathology, these differences did not reach statistical significance. Between 2014 and 2019, a significant increase had occurred in statin use among patients undergoing elective TEVAR, from 56% in 2014 to 64% in 2019 (P = .007).

CONCLUSIONS

Preoperative statin therapy is associated with lower perioperative complication rates and 5-year mortality for patients undergoing TEVAR. All patients with known thoracic aortic pathology should receive statin therapy unless contraindications for the drug are present. For patients undergoing elective TEVAR, the statin prescription percentage should be considered a quality metric, and further implementation research should occur to improve preoperative statin use.