Editor's Choice - Cohort Study Examining the Association Between Abdominal Aortic Size and Major Adverse Cardiovascular Events in Patients with Aortic and Peripheral Occlusive and Aneurysmal Disease

Abdominal aortic aneurysm histomorphology shows different inflammatory aspects among patients and is not associated with classic risk factors - the HistAAA study

AIMS

Abdominal aortic aneurysm (AAA) treatment is upon a diameter threshold. Attempts for medical growth abrogation have failed thus far. This study aims to elucidate the heterogeneity of AAA histomorphology in correlation to individual patient and aneurysm metrics.

METHODS AND RESULTS

Samples from the left anterior aneurysm wall underwent histologic analysis including angiogenesis, calcification, fibrosis, type and grade of inflammation in adventitia and media. Clinical information and state of aneurysm (intact, symptomatic, ruptured, inflammatory) were retrieved. Semi-automated geometric analysis (Endosize©, Therenva) and finite element methods (A4Clinics© Research Edition, Vascops GmbH) were included.364 patients' samples (85.4% male, median age 69 years) were scored for acute or chronic inflammation, both not associated with rupture (52x), symptomatic disease (37x) or diameter (57 [52-69] mm; p = 0.87). The degree of fibrosis and the presence of angiogenesis were significantly higher (both p < 0.001) with increasing inflammation, which in turn significantly decreased with patient age (est = - 0.015/year, p = 0.017). No significant differences were seen for acute (vs. elective), male (vs. female) or diabetic patients. Aneurysm geometry (n=252) or annual growth rate (n=142) were not associated with histologic characteristics. Yet, local luminal thrombus formation was significantly higher with increasing inflammation (p = 0.04).

CONCLUSION

Type and degree of inflammation are the most distinguishable histologic characteristics in the AAA wall between individual patients, yet are not associated with diameter or rupture. Local luminal thrombus formation is associated with inflammatory features and suggests a vivid bio-physical compartment with intra-individual age-dependent differences.

Lower Rates of Abdominal Aortic Aneurysm Repair and Higher Long-term Aortic Mortality in Women Compared With Men: Results of a Population-Based Study Spanning 4 Decades

OBJECTIVE

To determine the population-level impact of screening and endovascular repair as well as mortality in women with abdominal aortic aneurysms (AAAs).

PATIENTS AND METHODS

We conducted a population-based cohort study of patients from Olmsted County, Minnesota, in whom AAA was diagnosed between January 1, 1980, and December 31, 2017. The AAAs were identified using the International Classification of Diseases, Ninth and Tenth Revisions and Current Procedural Terminology codes with medical record review to confirm the diagnosis and identify late events. Survival analysis for overall and aortic mortality was performed and stratified based on sex and repair status.

RESULTS

There were 1537 patients in our study cohort (75% [1156] male; median age, 74 years). Compared with men, women were older (80 vs 73 years; P<.001), had smaller initial aneurysm size (4 vs 4.3 cm; P<.001), underwent AAA repair less frequently (26% [99] vs 41% [475]; P<.001), and had similar 30-day mortality from AAA repair (4% [4 of 381] vs 5% [22 of 1156]; P=.50). Median follow-up was 18 years. Aortic and all-cause mortality at 10 and 20 years were highest in females who did not undergo repair (hazard ratio, 3; 95% CI, 1.8 to 4.5; P<.001), as compared with all men and women who underwent AAA repair. Cumulative aortic mortality analyzed with non-aortic-related deaths as a competing risk factor remained significantly higher in NRF (15% [40 of 282] vs 5% to 8% in other groups; 5/99 in females undergoing repair, 39/681 in non repaired males and 37/475 in males who underwent repair, P=.001). All patients with aortic-related mortality had refused repair due to older age and comorbidities, except 2 females with ruptures of 4.8 and 5.5 cm AAAs awaiting repair.

CONCLUSION

Abdominal aortic aneurysms are diagnosed in women almost a decade later and repaired less often than in men. There is a 3-fold greater long-term aortic-related mortality in women not undergoing AAA repair compared with men and women who underwent AAA repair.

Rates of Stroke in Patients With Different Presentations of Carotid Artery Stenosis

OBJECTIVE

Carotid artery stenosis may present without the classical symptoms of transient ischaemic attack or stroke but the rates of stroke for these presentations is unknown. The aim of this study was to examine the rates of stroke in patients with different presentations of carotid artery stenosis.

METHODS

A multicentre prospective cohort study was conducted across three Australian vascular centres with low rates of surgical treatment of patients without transient ischaemic attack or stroke. Patients with a 50 - 99% carotid artery stenosis presenting with non-focal symptoms (e.g., dizziness or syncope; n = 47), prior contralateral carotid endarterectomy (n = 71), prior ipsilateral symptoms more than six months earlier (n = 82), and no symptoms (n = 304) were recruited. The primary outcome was ipsilateral ischaemic stroke. Secondary outcomes were any ischaemic stroke and cardiovascular death. Data were analysed using Cox proportional hazard and Kaplan-Meier analyses.

RESULTS

Between 2002 and 2020, 504 patients were enrolled (mean age 71 years, 30% women) and followed for a median of 5.1 years (interquartile range 2.5, 8.8; 2 981 person years). Approximately 82% were prescribed antiplatelet therapy, 84% were receiving at least one antihypertensive drug, and 76% were prescribed a statin at entry. After five years the incidence of ipsilateral stroke was 6.5% (95% confidence interval [CI] 4.3 - 9.5). There were no statistically significant differences in the annual rate of ipsilateral stroke among people with non-focal symptoms (2.1%; 95% CI 0.8 - 5.7), prior contralateral carotid endarterectomy (0.2%; 0.03 - 1.6) or ipsilateral symptoms > 6 months prior (1.0%; 0.4 - 2.5) compared with those with no symptoms (1.2%; 0.7 - 1.8; p = .19). There were no statistically significant differences in secondary outcomes across groups.

CONCLUSION

This cohort study showed no large differences in stroke rates among people with different presentations of carotid artery stenosis.

The Incidence of IgG4-Related and Inflammatory Abdominal Aortic Aneurysm Is Rare in a 101 Patient Cohort

Abdominal aortic aneurysms (AAA) are the most frequent aortic dilation, with considerable morbidity and mortality. Inflammatory (infl) and IgG4-positive AAAs represent specific subtypes of unclear incidence and clinical significance. Here, histologic and serologic analyses with retrospective clinical data acquisition are investigated via detailed histology, including morphologic (HE, EvG: inflammatory subtype, angiogenesis, and fibrosis) and immunhistochemic analyses (IgG and IgG4). In addition, complement factors C3/C4 and immunoglobulins IgG, IgG2, IgG4 and IgE were measured in serum samples and clinical data uses patients' metrics, as well as through semi-automated morphometric analysis (diameter, volume, angulation and vessel tortuosity). A total of 101 eligible patients showed five (5%) IgG4 positive (all scored 1) and seven (7%) inflammatory AAAs. An increased degree of inflammation was seen in IgG4 positive and inflAAA, respectively. However, serologic analysis revealed no increased levels of IgG or IgG4. The operative procedure time was not different for those cases and the short-term clinical outcomes were equal for the entire AAA cohort. Overall, the incidence of inflammatory and IgG4-positive AAA samples seems very low based on histologic and serum analyses. Both entities must be considered distinct disease phenotypes. Short-term operative outcomes were not different for both sub-cohorts.

Association of Oral Anticoagulation Prescription with Clinical Events in Patients with an Asymptomatic Unrepaired Abdominal Aortic Aneurysm

Background: Most abdominal aortic aneurysms (AAA) have large volumes of intraluminal thrombus which has been implicated in promoting the risk of major adverse events. The aim of this study was to examine the association of therapeutic anticoagulation with AAA-related events and major adverse cardiovascular events (MACE) in patients with an unrepaired AAA. Methods: Patients with an asymptomatic unrepaired AAA were recruited from four sites in Australia. The primary outcome was the combined incidence of AAA repair or AAA rupture-related mortality (AAA-related events). The main secondary outcome was MACE (the combined incidence of myocardial infarction, stroke, or cardiovascular death). The associations of anticoagulation with these outcomes were assessed using Cox proportional hazard analyses (reporting hazard ratio, HR, and 95% confidence intervals, CI) to adjust for other risk factors. Results: A total of 1161 patients were followed for a mean (standard deviation) of 4.9 (4.0) years. Of them, 536 (46.2%) patients had a least one AAA-related event and 319 (27.5%) at least one MACE. In the sample, 98 (8.4%) patients were receiving long-term therapeutic anticoagulation using warfarin (84), apixaban (7), rivaroxaban (6), or dabigatran (1). Prescription of an anticoagulant was associated with a reduced risk of an AAA-related event (adjusted HR 0.61; 95% CI 0.42, 0.90, p = 0.013), but not MACE (HR 1.16; 95% CI 0.78, 1.72, p = 0.476). Conclusions: These findings suggest that AAA-related events but not MACE may be reduced in patients prescribed an anticoagulant medication. Due to the inherent biases of observational studies, a randomized controlled trial is needed to assess whether anticoagulation reduces the risk of AAA-related events.

Aortic Area as an Indicator of Subclinical Cardiovascular Disease

Aim:

Outward arterial remodeling occurs early in cardiovascular disease (CVD) and, as such, measuring arterial dimension may be an early indicator of subclinical disease.

Objective:

The objective of our study was to measure area at three aortic locations: The ascending thoracic (ASC), the descending thoracic (DSC), and the abdominal (ABD), and to test for association with traditional CVD risk factors and subclinical CVD throughout the body.

Methods:

We measured ASC, DSC, and ABD using computed tomography (CT) in 408 African ancestry men aged 50-89 years. We assessed prevalent CVD risk factors via participant interview and clinical exam, and subclinical CVD, including carotid atherosclerosis through B-mode carotid ultrasound, vascular calcification via chest and abdominal CT, and arterial stiffness via pulse-wave velocity (PWV).

Results:

As expected, all aortic areas were in correlation with each other (r=0.39-0.63, all p<0.0001) and associated with greater age, greater body size, and hypertension (p≤0.01 for all). After adjustment for traditional CVD risk factors, ASC was positively associated with carotid atherosclerosis (p<0.01). A greater area at each location was associated with greater PWV (p<0.03 for all), with the DSC region showing the most significant association.

Conclusion:

This is the first study to test the association of aortic area measured at multiple points with subclinical CVD. We found that combined CT assessment of ascending and descending aortic area may indicate a high risk of prevalent subclinical CVD elsewhere in the body independent of age, body size, and blood pressure.