Carotid Atherosclerosis and Relation to Growth of Infrarenal Aortic Diameter and Follow-up Diameter: The Tromsø Study

Two-dimensional echocardiographic and strain values of the proximal thoracic aorta in a normal sub-Saharan African population

BACKGROUND

There is limited data regarding reference ranges for aortic dimensions in African populations. This study aims to establish normal reference ranges for echocardiographic dimensions and circumferential strain (CS) of the proximal thoracic aorta in a healthy sub-Saharan African population.

METHODS

This was a secondary analysis of data from a prospective cross-sectional study of 88 participants conducted at Chris Hani Baragwanath Hospital (2017-2019). Aortic measurements were obtained as per the 2015 American Society of Echocardiography guidelines using a Philips iE33 system. Circumferential Strain was measured using Philips QLAB version 11.0 software offline semi-automated analysis of speckle-based strain 2-D speckle-tracking software (Amsterdam, The Netherlands).

RESULTS

Mean age was 37.22 ± 10.79 years (41% male). The mean diameter at the aortic annulus, sinuses, sino-tubular junction (STJ) and ascending aorta (AAO) were 19.11 ± 2.38 mm, 27.40 ± 6.11 mm, 25.32 ± 3.52 mm and 25.36 ± 3.38 mm, respectively. Males had larger absolute and indexed aortic diameters at all levels when compared to females. The mean aorta CS was 11.97 ± 5.05%. There was no significant difference in CS based on gender (12.19 ± 5.04% vs 11.51 ± 5.02%, P = 0.267). On multivariate linear regression analysis, male sex was the most significant predictor of increased diameter at the level of the aortic annulus (r = 0.17, P = 0.014), body surface area was the most significant predictor at the sinuses (r = 0.17, P = 0.014) and AAO (r = 0.30, P < 0.001), while age was the most significant predictor at the STJ (r = 0.27, P = 0.004). There was a negative correlation between age and aortic CS (r = - 0.12, P < 0.001). The most important predictor of aorta CS was age, on multivariate analysis (r = - 0.19, P = 0.024).

CONCLUSIONS

This study provides normal reference ranges for dimensions of the proximal aorta and circumferential strain (CS) in a sub-Saharan African population according to age, sex, and body habitus. It serves as a platform for future larger studies and allows for risk stratification of cardiovascular disease in an African population.

Potential influencing factors of aortic diameter at specific segments in population with cardiovascular risk

Background

Aortic diameter is a critical parameter for the diagnosis of aortic dilated diseases. Aortic dilation has some common risk factors with cardiovascular diseases. This study aimed to investigate potential influence of traditional cardiovascular risk factors and the measures of subclinical atherosclerosis on aortic diameter of specific segments among adults.

Methods

Four hundred and eight patients with cardiovascular risk factors were prospectively recruited in the observational study. Comprehensive transthoracic M-mode, 2-dimensional Doppler echocardiographic studies were performed using commercial and clinical diagnostic ultrasonography techniques. The aortic dimensions were assessed at different levels: (1) the annulus, (2) the mid-point of the sinuses of Valsalva, (3) the sinotubular junction, (4) the ascending aorta at the level of its largest diameter, (5) the transverse arch (including proximal arch, mid arch, distal arch), (6) the descending aorta posterior to the left atrium, and (7) the abdominal aorta just distal to the origin of the renal arteries. Multivariable linear regression analysis was used for evaluating aortic diameter-related risk factors, including common cardiovascular risk factors, co-morbidities, subclinical atherosclerosis, lipid profile, and hematological parameters.

Results

Significant univariate relations were found between aortic diameter of different levels and most traditional cardiovascular risk factors. Carotid intima-media thickness was significantly correlated with diameter of descending and abdominal aorta. Multivariate linear regression showed potential effects of age, sex, body surface area and some other cardiovascular risk factors on aortic diameter enlargement. Among them, high-density lipoprotein cholesterol had a significantly positive effect on the diameter of ascending and abdominal aorta. Diastolic blood pressure was observed for the positive associations with diameters of five thoracic aortic segments, while systolic blood pressure was only independently related to mid arch diameter.

Conclusion

Aortic segmental diameters were associated with diastolic blood pressure, high-density lipoprotein cholesterol, atherosclerosis diseases and other traditional cardiovascular risk factors, and some determinants still need to be clarified for a better understanding of aortic dilation diseases.

Both Small and Large Infrarenal Aortic Size is Associated with an Increased Prevalence of Ischaemic Heart Disease

OBJECTIVE

Past studies have suggested a potential "J shaped" relationship between infrarenal aortic diameter and both cardiovascular disease (CVD) prevalence and all cause mortality. However, screening programmes have focused primarily on large (aneurysmal) aortas. In addition, aortic diameter is rarely adjusted for body size, which is particularly important for women. This study aimed to investigate specifically the relationship between body size adjusted infrarenal aortic diameter and baseline prevalence of CVD.

METHODS

A retrospective analysis was performed on a total of 4882 elderly (>50 years) participants (mean age 69.4 ± 8.9 years) for whom duplex ultrasound to assess infrarenal abdominal aortic diameters had been performed. History of CVDs, including ischaemic heart disease (IHD), and associated risk factors were collected at the time of assessment. A derivation cohort of 1668 participants was used to select cut offs at the lower and upper 12.5% tails of the aortic size distributions (aortic size index of <0.84 and >1.2, respectively), which was then tested in a separate cohort.

RESULTS

A significantly elevated prevalence of CVD, and specifically IHD, was observed in participants with both small and large aortas. These associations remained significant following adjustment for age, sex, diabetes, hypertension, dyslipidaemia, obesity (body mass index), and smoking.

CONCLUSION

The largest and smallest infrarenal aortic sizes were both associated with prevalence of IHD. In addition to identifying those with aneurysmal disease, it is hypothesised that screening programmes examining infrarenal aortic size may also have the potential to improve global CVD risk prediction by identifying those with small aortas.

The impact of statin therapy after surgical or endovascular treatment of cerebral aneurysms

OBJECTIVE

Cerebral aneurysms represent the most common cause of spontaneous subarachnoid hemorrhage. Statins are lipid-lowering agents that may expert multiple pleiotropic vascular protective effects. The authors hypothesized that statin therapy after coil embolization or surgical clipping of cerebral aneurysms might improve clinical outcomes.

METHODS

This was a retrospective cohort study using the National Health Insurance Service-National Sample Cohort Database in Korea. Patients who underwent coil embolization or surgical clipping for cerebral aneurysm between 2002 and 2013 were included. Based on prescription claims, the authors calculated the proportion of days covered (PDC) by statins during follow-up as a marker of statin therapy. The primary outcome was a composite of the development of stroke, myocardial infarction, and all-cause death. Multivariate time-dependent Cox regression analyses were performed.

RESULTS

A total of 1381 patients who underwent coil embolization (n = 542) or surgical clipping (n = 839) of cerebral aneurysms were included in this study. During the mean (± SD) follow-up period of 3.83 ± 3.35 years, 335 (24.3%) patients experienced the primary outcome. Adjustments were performed for sex, age (as a continuous variable), treatment modality, aneurysm rupture status (ruptured or unruptured aneurysm), hypertension, diabetes mellitus, household income level, and prior history of ischemic stroke or intracerebral hemorrhage as time-independent variables and statin therapy during follow-up as a time-dependent variable. Consistent statin therapy (PDC > 80%) was significantly associated with a lower risk of the primary outcome (adjusted hazard ratio 0.34, 95% CI 0.14-0.85).

CONCLUSIONS

Consistent statin therapy was significantly associated with better prognosis after coil embolization or surgical clipping of cerebral aneurysms.

Association of carotid atherosclerosis and stiffness with abdominal aortic aneurysm: The atherosclerosis risk in communities (ARIC) study

BACKGROUND AND AIMS

Individuals with atherosclerosis and stiffness often have increased abdominal aortic diameters, but prospective evidence linking them to the risk of abdominal aortic aneurysm (AAA) is limited.

METHODS

We prospectively examined the relationship of carotid atherosclerosis and stiffness with future risk of AAA in ARIC. At Visits 1 (1987-89) or 2 (1990-1992), we assessed carotid atherosclerosis (represented by greater carotid intima-media thickness [cIMT] or presence of atherosclerotic plaque) and lower carotid distensibility (reflected by a higher carotid Beta Index). We identified incident, clinical AAAs during follow-up through 2011 using hospital discharge codes, Medicare outpatient diagnoses, or death certificates.

RESULTS

Participants' mean age at baseline was 54.2 years (SD 5.8), 45% were male and 73% white. During a median of 22.5 years of follow-up, 542 clinical AAAs were ascertained. After multivariable adjustment, the presence of carotid atherosclerotic plaque at baseline was associated with 1.31 (95% CI: 1.10-1.57; p = 0.003) times higher risk of clinical AAA. Greater cIMT and Beta Index were also associated with clinical AAA with a dose-response across quartiles (p trend for both: 0.006; hazard ratios [95% CI] for the highest vs. lowest quartiles: 1.55 [1.13-2.11] and 1.68 [1.16-2.43], respectively). The associations of cIMT and Beta Index with AAA were independent of each other.

CONCLUSIONS

This prospective population-based study found that indices of greater carotid atherosclerosis and lower carotid distensibility are markers of increased AAA risk.

Family history of atherosclerotic vascular disease is associated with the presence of abdominal aortic aneurysm

We investigated whether family history (FHx) of atherosclerotic cardiovascular disease (ASCVD) was associated with presence of abdominal aortic aneurysm (AAA). The study cohort comprised of 696 patients with AAA (70±8 years, 84% men) and 2686 controls (68±10 years, 61% men) recruited from noninvasive vascular and stress electrocardiogram (ECG) laboratories at Mayo Clinic. AAA was defined as a transverse diameter of abdominal aorta ⩾ 3 cm or history of AAA repair. Controls were not known to have AAA. FHx was defined as having at least one first-degree relative with aortic aneurysm or with onset of ASCVD (coronary, cerebral or peripheral artery disease) before age 65 years. FHx of aortic aneurysm or ASCVD were each associated with presence of AAA after adjustment for age, sex, conventional risk factors and ASCVD: adjusted odds ratios (OR; 95% confidence interval): 2.17 (1.66-2.83, p < 0.01) and 1.31 (1.08-1.59, p < 0.01), respectively. FHx of ASCVD remained associated with AAA after additional adjustment for FHx of aortic aneurysm: adjusted OR: 1.27 (1.05-1.55, p = 0.01). FHx of ASCVD in multiple arterial locations was associated with higher odds of having AAA: the adjusted odds were 1.23 times higher for each additionally affected arterial location reported in the FHx (1.08-1.40, p = 0.01). Our results suggest both unique and shared environmental and genetic factors mediating susceptibility to AAA and ASCVD.

Influence of apolipoprotein E, age and aortic site on calcium phosphate induced abdominal aortic aneurysm in mice

OBJECTIVE

To assess relevant features of abdominal aortic aneurysms (AAA) induced by calcium phosphate within a mouse model. Specifically we investigated: (1) whether apolipoprotein E deficiency and older age promoted AAA formation, and (2) whether the local application of calcium phosphate affected the size of distant aortic segments.

METHODS

AAA was induced by application of calcium phosphate to the infra-renal aortas of 3 and 7 month old male mice. AAA induction was assessed by calculating expansion of the infra-renal aortic diameter over 1-4 weeks. Aortic samples were assessed to quantify calcification, macrophages infiltration, elastic lamellar degradation and apoptosis. Blood pressure was measured by the tail cuff method, and plasma concentrations of total cholesterol, low density lipoprotein and very low density lipoprotein cholesterol, and pro-inflammatory cytokines were measured using commercially available kits. The maximum diameters of the aortic arch, thoracic and supra-renal aorta at sacrifice were measured by morphometry and the mean maximal diameter of these three aortic segments was calculated.

RESULTS

The median expansion of the infra-renal aorta 2 weeks after AAA induction was significantly greater in apolipoprotein E deficient (ApoE(-/-)) mice than in age- and gender-matched wild type controls [275.8% (IQR 193.8%-348.5%) versus 94.7% (IQR 47.8%-163.4%), P = 0.02]. The greater aortic expansion in ApoE(-/-) mice was associated with aortic calcification, macrophage infiltration, elastic lamellar degradation and apoptosis of cells in the media and adventitia. The plasma low density lipoprotein/very low density lipoprotein cholesterol concentrations 2 weeks after AAA induction were positively correlated with the expansion of the infra-renal aorta induced by calcium phosphate. The median expansion of the infra-renal aorta 2 weeks after AAA induction was similar in 3 and 7 month old wild type mice. The local administration of calcium phosphate was associated with an increase in the mean maximal diameter of distant aortic segments, but not associated with changes in the concentrations of pro-inflammatory markers in either the plasma or the spleen.

CONCLUSION

This study suggests that apolipoprotein E deficiency, but not age, predisposes to AAA induced within the calcium phosphate model. Increased AAA expansion in ApoE(-/-) mice was associated with calcification, macrophage infiltration, elastic lamellar degradation, and cell apoptosis. Local application of calcium phosphate also promoted dilation of distant aortic segments.

An unusual cause of chronic otitis media with effusion

OBJECTIVE

To describe an unusual cause for hearing loss in an adult.

CASE REPORT

A 37-year-old man presented with a year's history of right-sided hearing loss. He had no history of trauma, or local or systemic infection. He was otherwise well, took no medication and had no allergies. He had a two-year history of low back pain. On examination, he had a retracted right tympanic membrane with no perforation, and a middle-ear effusion. Nasendoscopy was normal. Examination of other systems was unremarkable. Computed tomography of the temporal bones with contrast demonstrated a large, right, intra-cerebral internal carotid artery aneurysm compressing the eustachian tube. After a balloon occlusion test, he underwent endovascular occlusion of the parent vessel. He made a good post-operative recovery. A subsequent abdominal ultrasound excluded an abdominal aneurysm as a cause of his low back pain. His hearing had not improved three days post-operatively, and was to be formally assessed and monitored in the clinic.

DISCUSSION

A carotid aneurysm is a rare cause of eustachian tube compression but must be considered in the differential diagnosis of conductive hearing loss. Aneurysms may have systemic causes, and their presence in other systems should be excluded as they may be multiple.