Multicentric clinical evaluation of a computed tomography-based fully automated deep neural network for aortic maximum diameter and volumetric measurements

OBJECTIVE

This study aims to evaluate a fully automatic deep learning-based method (augmented radiology for vascular aneurysm [ARVA]) for aortic segmentation and simultaneous diameter and volume measurements.

METHODS

A clinical validation dataset was constructed from preoperative and postoperative aortic computed tomography angiography (CTA) scans for assessing these functions. The dataset totaled 350 computed tomography angiography scans from 216 patients treated at two different hospitals. ARVA's ability to segment the aorta into seven morphologically based aortic segments and measure maximum outer-to-outer wall transverse diameters and compute volumes for each was compared with the measurements of six experts (ground truth) and thirteen clinicians.

RESULTS

Ground truth (experts') measurements of diameters and volumes were manually performed for all aortic segments. The median absolute diameter difference between ground truth and ARVA was 1.6 mm (95% confidence interval [CI], 1.5-1.7; and 1.6 mm [95% CI, 1.6-1.7]) between ground truth and clinicians. ARVA produced measurements within the clinical acceptable range with a proportion of 85.5% (95% CI, 83.5-86.3) compared with the clinicians' 86.0% (95% CI, 83.9-86.0). The median volume similarity error ranged from 0.93 to 0.95 in the main trunk and achieved 0.88 in the iliac arteries.

CONCLUSIONS

This study demonstrates the reliability of a fully automated artificial intelligence-driven solution capable of quick aortic segmentation and analysis of both diameter and volume for each segment.

Trends among platelet function, arterial calcium, and vascular function measures

Arterial tonometry and vascular calcification measures are useful in cardiovascular disease (CVD) risk assessment. Prior studies found associations between tonometry measures, arterial calcium, and CVD risk. Activated platelets release angiopoietin-1 and other factors, which may connect vascular structure and platelet function. We analyzed arterial tonometry, platelet function, aortic, thoracic and coronary calcium, and thoracic and abdominal aorta diameters measured in the Framingham Heart Study Gen3/NOS/OMNI-2 cohorts (n = 3,429, 53.7% women, mean age 54.4 years ±9.3). Platelet reactivity in whole blood or platelet-rich plasma was assessed using 5 assays and 7 agonists. We analyzed linear mixed effects models with platelet reactivity phenotypes as outcomes, adjusting for CVD risk factors and family structure. Higher arterial calcium trended with higher platelet reactivity, whereas larger aortic diameters trended with lower platelet reactivity. Characteristic impedance (Zc) and central pulse pressure positively trended with various platelet traits, while pulse wave velocity and Zc negatively trended with collagen, ADP, and epinephrine traits. All results did not pass a stringent multiple test correction threshold (p < 2.22e-04). The diameter trends were consistent with lower shear environments invoking less platelet reactivity. The vessel calcium trends were consistent with subclinical atherosclerosis and platelet activation being inter-related.

Echocardiographic Phenotypes of Subclinical Organ Damage: Clinical and Prognostic Value in the General Population. Findings from the Pamela Study

Subclinical alterations in cardiac structure and function include a variety of abnormal phenotypes of established adverse prognostic significance such as left ventricular hypertrophy (LVH), alterations of LV geometry, left atrial (LA) enlargement, and aortic root (AR) dilatation. The excess cardiovascular (CV) risk associated with these phenotypes has been consistently demonstrated in different clinical settings such in patients with systemic hypertension, coronary heart disease, diabetes mellitus, chronic kidney disease, heart failure and in geneal population samples. The Pressioni Monitorate e Loro Associazioni (PAMELA), a longitudinal population-based study originally designed to assess the normality values, prognostic significance of office, home and 24-hour blood pressure, including among the many clinical and laboratory variables the collection of echocardiographic data, allowed to gather important information on the clinical prognostic significance of subclinical cardiac damage during a long follow-up period. This article summarizes the original findings provided by the PAMELA study on the clinical correlates and prognostic significance of echocardiographic markers of subclinical organa damage namely LVH, left atrial enlargement (LA) and AR dilatation at the community level.

Extended law of laplace for measurement of the cloverleaf anatomy of the aortic root

The cross-sectional shape of the aortic root is cloverleaf, not circular, raising controversy regarding how best to measure its radiographic "diameter" for aortic event prediction. We mathematically extended the law of Laplace to estimate aortic wall stress within this cloverleaf region, simultaneously identifying a new metric of aortic root dimension that can be applied to clinical measurement of the aortic root and sinuses of Valsalva on clinical computerized tomographic scans. Enforcing equilibrium between blood pressure and wall stress, finite element computations were performed to evaluate the mathematical derivation. The resulting Laplace diameter was compared with existing methods of aortic root measurement across four patient groups: non-syndromic aneurysm, bicuspid aortic valve, Marfan syndrome, and non-dilated root patients (total 106 patients, 62 M, 44 F). (1) Wall stress: Mean wall stress at the depth of the sinuses followed this equation: Wall stress = BP × Circumscribing circle diameter/(2 × Aortic wall thickness). Therefore, the diameter of the circle enclosing the root cloverleaf, that is, twice the distance between the center, where the sinus-to-commissure lines coincide, and the depth of the sinuses, may replace diameter in the Laplace relation for a cloverleaf cross-section (or any shaped cross-section with two or more planes of symmetry). This mathematically derived result was verified by computational finite element analyses. (2) Diameters: CT scan measurements showed a significant difference between this new metric, the Laplace diameter, and the sinus-to-commissure, mid-sinus-to-mid-sinus, and coronal measurements in all four groups (p-value < 0.05). The average Laplace diameter measurements differed significantly from the other measurements in all patient groups. Among the various possible measurements within the aortic root, the diameter of the circumscribing circle, enclosing the cloverleaf, represents the diameter most closely related to wall stress. This diameter is larger than the other measurements, indicating an underestimation of wall stress by prior measurements, and otherwise provides an unbiased, convenient, consistent, physics-based measurement for clinical use. "Diameter" applies to circles. Our mathematical derivation of an extension of the law of Laplace, from circular to cloverleaf cross-sectional geometries of the aortic root, has implications for measurement of aortic root "diameter." The suggested method is as follows: (1) the "center" of the aortic root is identified by drawing three sinus-to-commissure lines. The intersection of these three lines identifies the "center" of the cloverleaf. (2) The largest radius from this center point to any of the sinuses is identified as the "radius" of the aortic root. (3) This radius is doubled to give the "diameter" of the aortic root. We find that this diameter best corresponds to maximal wall stress in the aortic root. Please note that this diameter defines the smallest circle that completely encloses the cloverleaf shape, touching the depths of all three sinuses.

Type 2 diabetes has a protective causal association with thoracic aortic aneurysm: a Mendelian randomization study

BACKGROUND

Observational studies have reported an inverse association of type 2 diabetes (T2D) with thoracic aortic aneurysm (TAA). However, the causality of the association has not been established yet. The present study aims to clarify the causal relationship between T2D and TAA via a Mendelian randomization (MR) approach.

METHODS

Causality of associations were assessed using a two-sample MR framework. Genome-wide association study (GWAS) summary statistics were obtained for T2D, glycated hemoglobin (HbA1c), fasting glucose (FG) and fasting insulin (FI) as exposures, and TAA, ascending aortic diameter (AAoD) and descending aortic diameter (DAoD) as outcomes. Four different methods (inverse variance weighted [IVW], weight median, MR-Egger and MR-PRESSO) were used to calculate causal estimates. Heterogeneity and horizontal pleiotropy were assessed using Cochran Q test and MR-Egger regression intercept, respectively.

RESULTS

Genetically predicted T2D was inversely associated with the risk of TAA (OR: 0.931, 95% CI 0.870 to 0.997, p = 0.040, IVW method) and AAoD (Beta: -0.065, 95%CI -0.099 to  - 0.031, p = 1.7e-04, IVW method), but not with DAoD (p > 0.05). Genetically predicted FG level was inversely associated with AAoD (Beta: -0.273, 95% CI -0.396 to -0.150, p = 1.41e-05, IVW method) and DAoD (Beta: -0.166, 95% CI -0.281 to -0.051, p = 0.005, IVW method), but not with TAA (p > 0.05). The effect of genetically predicted HbA1c and FI on TAA, AAoD and DAoD did not reach statistical significance (p > 0.05).

CONCLUSIONS

Genetic predisposition to T2D decreases the risk of TAA. Genetically predicted T2D is inversely associated with AAoD, but not with DAoD. Genetically predicted FG level was inversely associated with AAoD and DAoD.

Ascending Aorta Dissection Before 5.5 cm Diameter; "It Wasn't Raining When Noah Built the Ark"

INTRODUCTION

The aim of this study was to compare mean maximum ascending aortic diameter at the time of acute aortic dissection with the current surgical threshold for elective ascending aortic operations on non-syndromic thoracic aortic aneurysms.

MATERIAL AND METHODS

All consecutive non-syndromic adult patients admitted for acute type A aortic dissection in a single tertiary centre were prospectively enrolled from April 2020 to March 2021. The primary endpoint was the difference between mean maximum aortic diameter at the time of dissection and the 5.5 cm threshold for elective repair. Secondary endpoints included 30-day/in-hospital mortality, aortic length and comparison with normal controls, length/height ratio index, "actual" preoperative Euroscore II and "predicted" Euroscore II if electively operated.

RESULTS

Among 31 patients ageing 67.3±12.03 years on average, mean maximum aortic diameter at the time of dissection was 5.13±0.66 cm, significantly lower than the guidelines-derived surgical threshold of 5.5 cm (p=0.004). Mean aortic length was 11±1.47 cm, also significantly longer compared normal controls reported in the literature (p<0.001). The 30-day/in-hospital mortality was 35.5%. Mean length/height ratio index was 6.18±0.76 cm/m. Finally, mean "actual" preoperative Euroscore II was 10.43±4.07 which was significantly higher than the 1.47±0.57 "predicted" Euroscore II (p<0.05).

CONCLUSIONS

The maximum aortic diameter at the time of acute type A aortic dissection of non-syndromic cases was significantly lower than the current recommendation for elective repair. Lowering of the current diameter-based surgical threshold of 5.5 cm may be profitable in terms of prevention, but further investigations should be undertaken. Length-based thresholds could also add to timely aortic dissection prevention.

Snoring and aortic dimension in Marfan syndrome

Recent reports suggest that self-reported snoring, which is a feature of obstructive sleep apnea, is associated with aortic enlargement in Marfan syndrome (MFS). Objective assessment of snoring although lacking, could provide a rational for OSA screening in MFS patients. Our goal in this study was to examine the association between objective measurements of snoring with OSA and aortic size in persons with MFS. Consecutive persons with MFS who reported snoring were recruited at Johns Hopkins, completed the Epworth Sleepiness Scale (ESS) and underwent overnight polysomnography during which inspiratory sound was captured. We measured breath-by-breath peak decibel levels and snoring was defined as flow limitation with sound ≥ 40 dB(A). OSA was defined as an apnea-hypopnea-index (AHI) ≥ 15 or AHI: 5-15 and ESS > 10. Participants' aortic data were collated to ascertain aortic root diameter. Regression models were used to determine the relationship of snoring breath% with OSA and aortic root diameter. In our cohort (M|F:13|16, Age: 37.0 ± 15.5 years, Aortic diameter; 38.9 ± 4.8 mm), a 1-unit increase in snoring breath percentage increased the odds of having OSA by 5% in both the unadjusted (OR = 1.05, p = 0.040) model, and a model adjusted for age and sex (OR = 1.05, p = 0.048). Similarly, a 10-unit increase in snoring breath percentage was associated with a 1 mm increase in contemporaneous aortic-root-diameter in both unadjusted (β = 0.09, p = 0.007), and adjusted (β = 0.08, p = 0.023) models. Objective snoring assessment could provide a means for identifying persons with MFS who need sleep studies, who may also be at risk for more severe aortic disease.

Ultrasound-based method for individualized estimation of central aortic blood pressure from flow velocity and diameter

Central aortic blood pressure (CABP) is a better predictor for cardiovascular events than brachial blood pressure. However, direct CABP measurement is invasive. The objective of this paper is to develop an ultrasound-based method using individualized Windkessel (WK) models for non-invasive estimation of CABP. Three WK models (with two-, three- and four-element WK, named, WK2, WK3 and WK4, respectively) were created and the model parameters were individualized based on aortic flow velocity and diameter waveforms measured by ultrasound (US). Experimental data were acquired in 42 subjects aged 21-67 years. The CABP estimated by WK models was compared with the reference CABP obtained using a commercial system. The results showed that the overall performance of the WK3 and WK4 models was similar, outperforming the WK2 model. The estimated CABP based on WK3/WK4 model showed good agreement with the reference CABP: the absolute errors of systolic blood pressure (SBP), 2.4 ± 2.1/2.4 ± 2.0 mmHg; diastolic blood pressure (DBP), 1.4 ± 1.1/1.7 ± 1.5 mmHg; mean blood pressure (MBP), 1.3 ± 0.8/1.3 ± 0.8 mmHg; pulse pressure (PP), 3.0 ± 2.3/3.2 ± 2.6 mmHg; the root mean square error (RMSE) of the waveforms, 2.5 ± 1.0/2.6 ± 1.1 mmHg. Therefore, the proposed method can provide a non-invasive CABP estimation during routine cardiac US examination.

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.

Artificial intelligence measuring the aortic diameter assist in identifying adverse blood pressure status including masked hypertension

INTRODUCTION AND OBJECTIVES

Artificial intelligence (AI) made it achievable that aortic dilation could be measured in CT images indirectly, while aortic diameter (AD) has the certain relationship with blood pressure. It was potential that the blood pressure condition be determined by AD measurement using the data obtained from a CT scanning especially in identifying masked hypertension and predicting the risk of poor control of blood pressure (BP) which was easy to elude diagnosis in clinic. We aimed to evaluate the possibility of utilizing AD by AI for predicting the risk of adverse BP status (including masked hypertension or poor BP control) and the optimal thoracic aortic position in measurement as well as the cutoff value for predicting the risk.

METHODS

Eight hundred and one patients were enrolled in our study. AI-Rad Companion Cardiovascular (K183268 FDA approved) was used to perform automatic aorta measurement in thoracic CT images at nine key positions based on AHA guidelines. Data was post processed by software from AI-Rad Companion undergone rigorous clinical validation by both FDA and CE as verification of its efficacy and usability. The AD's risk and diagnostic value was assessed in identifying hypertension in the general population, in identifying the poor BP controlled in the hypertension population, and in screening masked hypertension in the general population respectively by multiple regression analysis and receiver operating curve analysis.

RESULTS

AD measured by AI was a risk factor for adverse BP status after clinical covariates adjustment (OR = 1.02 ~ 1.26). The AD at mid descending aorta was mostly affected by BP particularly, which is optimal indicator in identifying hypertension in the general population (AUC = 0.73) and for screening masked hypertension (AUC = 0.78).

CONCLUSION

Using AI to measure the AD of the aorta, particularly at the position of mid descending aorta, is greatly valuable for identifying people with poor BP status. It will be possible to reveal more clinical information reflected by ordinary CT images and enrich the screening methods for hypertension, especially masked hypertension.PLAIN LANGUAGE SUMMARYHTN has a significant adverse effect on arterial deformation. BP and arterial dilation promote each other in a vicious circle. Arterial dilation may not be restricted by apparent fluctuations in BP and is objective evidence of an undesirable BP state. The accuracy of AD measurements by AI on chest CT images has been verified. There has not been the application of AD measurement by AI in the scene of poor BP status in clinical practice.In this study, we applied AI to measure the diameter of the aorta in nine consecutive positions. We explored the association between AD at various positions and BP levels and the possibility that AD in identifying poor BP status in different populations. We found that the AD at the MD is of great value in screening MH and evaluating the control state of BP in HTN. It will be possible to significantly expand the clinical information reflected by ordinary CT images and enrich the screening methods for HTN, especially MH.

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

OBJECTIVE

The aim of this study was to examine whether there were independent associations between abdominal aortic diameter, size index, and height index and the risk of major adverse events in patients referred for treatment of various types of aortic and peripheral occlusive and aneurysmal disease (APOAD).

METHODS

In total, 1 752 participants with a variety of APOADs were prospectively recruited between 2002 and 2020 and had a maximum abdominal aortic diameter, aortic size index (aortic diameter relative to body surface area), and aortic height index (aortic diameter relative to height) measured by ultrasound at recruitment. Participants were followed for a median of 4.6 years (interquartile range 2.0 - 8.0 years) to record outcome events, including major adverse cardiovascular events (MACE), peripheral artery surgery, abdominal aortic aneurysm (AAA) events (rupture or repair), and all cause mortality. The association between aortic size and events was assessed using Cox proportional hazard analysis. The ability of aortic size to improve risk of events classification was assessed using the net reclassification index (NRI).

RESULTS

After adjusting for other risk factors, larger aortic diameter was associated with an increased risk of MACE (hazard ratio [HR] 1.17, 95% confidence interval [CI] 1.05 - 1.31), requirement for peripheral artery surgery (HR 2.05, 95% CI 1.90 - 2.22), AAA events (HR 3.01, 95% CI 2.77 - 3.26), and all cause mortality (HR 1.20, 95% CI 1.08 - 1.32). Findings were similar for aortic size and aortic height indices. According to the NRI, all three aortic size measures significantly improved classification of risk of peripheral artery surgery and AAA events but not MACE. Aortic size index, but not aortic diameter or aortic height index, significantly improved the classification of all cause mortality risk.

CONCLUSION

Larger abdominal aortic diameter, size index, and height index are all independently associated with an increased risk of major adverse events in patients with established vascular disease.

Proximal aortic aneurysms: correlation of maximum aortic diameter and aortic wall thickness

OBJECTIVES

The goal of therapy of proximal aortic aneurysms is to prevent an aortic catastrophe, e.g. acute dissection or rupture. The decision to intervene is currently based on maximum aortic diameter complemented by known risk factors like bicuspid aortic valve, positive family history or rapid growth rate. When applying Laplace's law, wall tension is determined by pressure × radius divided by aortic wall thickness. Because current imaging modalities lack precision, wall thickness is currently neglected. The purpose of our study was therefore to correlate maximum aortic diameter with aortic wall thickness and known indices for adverse aortic events.

METHODS

Aortic samples from 292 patients were collected during cardiac surgery, of whom 158 presented with a bicuspid aortic valve and 134, with a tricuspid aortic valve. Aortic specimens were obtained during the operation and stored in 4% formaldehyde. Histological staining and analysis were performed to determine the thickness of the aortic wall.

RESULTS

Patients were 62 ± 13 years old at the time of the operation; 77% were men. The mean aortic dimensions were 44 mm, 41 mm and 51 mm at the aortic root, sinotubular junction and ascending aorta, respectively. Aortic valve stenosis was the most frequent (49%) valvular dysfunction, followed by aortic valve regurgitation (33%) and combined dysfunction (10%). The maximum aortic diameter at the ascending level did not correlate with the thickness of the media (R = 0.07) or the intima (R = 0.28) at the convex sample site. There was also no correlation of the ascending aortic diameter with age (R = -0.18) or body surface area (R = 0.07). The thickness of the intima (r = 0.31) and the media (R = 0.035) did not correlate with the Svensson index of aortic risk. Similarly, there was a low (R = 0.29) or absent (R = -0.04) correlation between the aortic size index and the intima or media thickness, respectively. There was a similar relationship of median thickness of the intima in the 4 aortic height index risk categories (P < 0.001).

CONCLUSIONS

Aortic diameter and conventional indices of aortic risk do not correlate with aortic wall thickness. Other indices may be required in order to identify patients at high risk for aortic complications.

Sex-specific criteria for repair should be utilized in patients undergoing aortic aneurysm repair

OBJECTIVE

Female patients are more likely to undergo repair of intact and ruptured abdominal aortic aneurysm (AAA) at smaller aortic diameter compared with male patients. By adjusting for inherent anatomic differences between sexes, aortic size index (ASI) and aortic height index (AHI) may provide an additional method for guiding treatment. We therefore analyzed sex-specific criteria for AAA repair using aortic diameter, ASI, and AHI.

METHODS

We identified all patients who underwent AAA repair between 2003 and 2019 in the Vascular Quality Initiative database. The Dubois and Dubois formula was used to calculate body surface area; aortic diameter was divided by body surface area to calculate ASI. Aortic diameter was divided by height to calculate AHI. Cumulative distribution curves were used to plot the proportion of patients who underwent repair of ruptured aneurysm according to aortic diameter, ASI, and AHI. Multivariable logistic regression modeling was used to identify the association of female sex with perioperative mortality and any major postoperative complication.

RESULTS

We identified 55,647 patients, of whom 12,664 were female (20%). For both intact and rupture repair, female patients were older, less likely to undergo endovascular aneurysm repair, and more likely to have comorbid conditions. Female patients underwent repair at smaller median aortic diameter compared with male patients for intact (5.4 vs 5.5 cm; P < .001) and rupture repair (6.7 vs 7.7 cm; P < .001). However, ASI was higher in female patients for both intact (3.1 vs 2.7 cm/m²; P < .001) and rupture repair (3.8 vs 3.7 cm/m²; P < .001), whereas AHI was higher in female patients for intact repair (3.3 vs 3.1 cm/m; P < .001) but lower for rupture repair (4.1 vs 4.3 cm/m; P < .001). When analyzing the cumulative distribution of rupture repair in male patients, 12% of rupture repairs were performed at an aortic diameter below 5.5 cm. To achieve the same proportion of rupture repair in female patients, the repair diameter was only 4.9 cm. However, when ASI and AHI were used, female and male patients both reached 12% of rupture repair at an ASI of 2.7 cm/m² and an AHI of 3.0 cm/m.

CONCLUSION

Our study provides data to strongly support the sex-specific 5.0-cm aortic diameter threshold suggested for repair in female patients by the Society for Vascular Surgery. The high percentage of patients undergoing rupture repair below 5.5 cm in male patients and 5.0 cm in female patients highlights the need to better identify patients at risk of rupture at smaller aortic diameters.

Aortic events in pregnant patients with Marfan syndrome. Lessons from a multicenter study

INTRODUCTION AND OBJECTIVES

Pregnancy in women with Marfan syndrome (MS) is associated with an increased risk of aortic events. The clinical evidence on pregnant patients with MS is limited and there is no specific consensus on their optimal management. We report our multicenter experience.

METHODS

From January 2004 to January 2020, 632 patients with MS underwent periodic monitoring in Marfan units. During this period, we identified all pregnant women with MS and analyzed the incidence of aortic events during pregnancy and puerperium.

RESULTS

There were 133 pregnancies in 89 women with MS (8 women with prior aortic surgery). There were no maternal deaths, but 5 women had aortic events during the third trimester and puerperium (type A dissections in 2, type B dissection in 1, and significant [≥ 3mm] aortic growth in 2). The aortic event rate was 3.7%. Pregestational aortic diameter≥ 40mm showed a nonsignificant association with aortic events (P=.058). Fetal mortality was 3% and 37.6% of births were cesarean deliveries.

CONCLUSIONS

Women with MS have an increased risk of aortic events during pregnancy, especially in the third trimester and postpartum period. Patients with MS and aortic diameters ≥40mm should be assessed in experienced centers for prophylactic aortic surgery before pregnancy. It is important to provide early diagnosis, prepregnancy study of the aorta, beta-blocker administration, and close monitoring during pregnancy, especially during the last trimester and postpartum.

Follow-up aortic dilatation in patients with repaired tetralogy of Fallot using cardiovascular magnetic resonance

Purpose

The study sought to determine the rate of aortic expansion and correlation with somatic growth in patients with repaired tetralogy of Fallot (rTOF), and predictors for determining the annual growth rate of the aorta (Ao-AGR).

Methods

Ninety-four rTOF patients (mean age 14.5 ± 4.4 years) with two cardiac magnetic resonance tests (CMR) (median duration 52 months, interquartile range, IQR 24-71) were analyzed for aortic diameter (AoD) at the annulus, the sinus of Valsalva (SoV), the sinotubular junction, and the ascending aorta (AAo), and compared with the normal limit AoD (NL-AoD) values. The median age-at-repair was 60 months (IQR 36-84). Ao-AGR and its index (Ao-AGRI) were derived from changes of the AoD and AoD-index, respectively, divided by the duration between the two studies. Three potential predictors (baseline AoD, sex, and age-at-repair) for the progression of Ao-AGR were analyzed.

Results

There was a significant larger AoD than NL-AoD (p < 0.001). Slow aortic growth was encountered in 78-85 % of patients. The Ao-AGR was slow, the median AGR ranged from 0.37 mm (IQR 0.13-0.72) at annulus to 0.56 mm (IQR 0.22-0.91) at AAo. There was a regression in Ao-AGRI, ranged from -1.41 mm (IQR -1.94, -0.87) at annulus to -2.36 mm (IQR -3.09, -1.63) at SoV. The three predictors were not correlated with severity of Ao-AGR.

Conclusion

Most adolescents with rTOF show significant aortic dilatation. There is a slow Ao-AGR with regression of Ao-AGRI, which may suggest that the rate of aortic growth is slower than the somatic growth. There are no significant predictors of the progression of Ao-AGR.

Diabetes, its duration, and the long-term risk of abdominal aortic aneurysm: The Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND AND AIMS

We aimed at comprehensively evaluate the independent association of diabetes and its duration with incident abdominal aortic aneurysm (AAA) and aortic diameter.

METHODS AND RESULTS

We prospectively studied incident AAA according to baseline glycemic status (diabetes, prediabetes, normal glycemia) in 13,116 ARIC participants (1990-1992) and the time-varying exposure of duration post incident diabetes in 11,675 participants (1987-1989) using Cox models. Additionally, we cross-sectionally explored ultrasound-based abdominal aortic diameter by glycemic status and cumulative duration of diabetes in 4710 participants (2011-2013) using linear regression models. Over ~20 years of follow-up, diabetes (vs. normal glycemia) at baseline was independently associated with lower AAA risk (489 cases) (hazard ratio: 0.71 [95%CI 0.51-0.99]), especially after 10 years (hazard ratio: 0.58 [0.38-0.87]). Prediabetes did not demonstrate an independent association. The inverse association was more evident with longer duration of diabetes (p for trend = 0.045), with 30-50% lower risk in eight years after diabetes diagnosis. The cross-sectional analysis demonstrated smaller aortic diameters with longer duration of diabetes (e.g., -0.76 mm [-1.24, -0.28] in diabetes with 8-12 years) compared to non-diabetes, whereas prediabetes consistently showed nominally greater diameter.

CONCLUSIONS

Diabetes, especially with longer duration, but not prediabetes, was independently associated with lower risk of AAA and smaller aortic diameter. Our findings suggest that long lasting clinical hyperglycemia plays an important role in the reduced AAA risk, and the reduced aortic diameter may be a structural mechanism behind this paradoxical association.

The effect of ticagrelor on growth of small abdominal aortic aneurysms-a randomized controlled trial

AIMS

To evaluate if ticagrelor, an effective platelet inhibitor without known non-responders, could inhibit growth of small abdominal aortic aneurysms (AAAs).

METHODS AND RESULTS

In this multi-centre randomized controlled trial, double-blinded for ticagrelor and placebo, acetylic salicylic acid naïve patients with AAA and with a maximum aortic diameter 35-49 mm were included. The primary outcome was mean reduction in log-transformed AAA volume growth rate (%) measured with magnetic resonance imaging (MRI) at 12 months compared with baseline. Secondary outcomes include AAA-diameter growth rate and intraluminal thrombus (ILT) volume enlargement rate. A total of 144 patients from eight Swedish centres were randomized (72 in each group). MRI AAA volume increase was 9.1% for the ticagrelor group and 7.5% for the placebo group (P = 0.205) based on intention-to-treat analysis, and 8.5% vs. 7.4% in a per-protocol analysis (P = 0.372). MRI diameter change was 2.5 mm vs. 1.8 mm (P = 0.113), US diameter change 2.3 mm vs. 2.2 mm (P = 0.778), and ILT volume change 12.9% vs. 10.4% (P = 0.590).

CONCLUSION

In this RCT, platelet inhibition with ticagrelor did not reduce growth of small AAAs. Whether the ILT has an important pathophysiological role for AAA growth cannot be determined based on this study due to the observed lack of thrombus modulating effect of ticagrelor.

TRIAL REGISTRATION

The TicAAA trial is registered at the US National Institutes of Health (ClinicalTrials.gov) #NCT02070653.

Association Between Cardiovascular Risk Factors and the Diameter of the Thoracic Aorta in an Asymptomatic Population in the Central Appalachian Region

BACKGROUND

Effects of cardiovascular (CV) risk factors on the diameter of the thoracic aorta have not been fully studied. This study examined the associations between CV risk factors and diameter of thoracic aorta.

MATERIALS AND METHODS

Study population comprised of 1273 asymptomatic adults aged ≥18 years from Central Appalachia region of the United States who participated in a coronary artery screening between January 2014 and December 2016. Descriptive statistics and multiple linear regression analyses were performed to examine associations between multiple CV risk factors and diameters of the thoracic aorta.

RESULTS

Mean (±SD) age of participants was 57.9±9.7 years; that of body mass index (BMI) was 29.4±5.9. The mean aortic sinus, ascending aorta, and descending aorta diameter were 34.1±4.4 mm, 33.8±4.4 mm, and 26.0±3.6 mm, respectively. Increasing age, being male, and having a higher BMI were associated with wider aortic sinus, ascending aorta, and descending aorta diameters. Hypertension (p < 0.05) and obesity (p < 0.0001) were significantly associated with wider diameter for all measured aortic diameters. Participants with diabetes had wider descending aorta compared to those without (26.6±3.9 mm vs. 25.9±3.5 mm, P = 0.012). Participants who had ever smoked a cigarette had significantly wider descending aorta diameter compared to never smokers (26.3±3.6 mm vs. 25.9±3.5 mm, p = 0.031).

CONCLUSIONS

The study results suggest that decreasing BMI and management of CV risk factors such as hypertension and modifying behavioral risk factors such as smoking are likely to be emphasized in order to decrease the rate of aortic dilatation and subsequent aortic dissection, if aortic dilatation is detected during a CT scan.

Locational impact of luminal communication on aortic diameter changes and reintervention in acute type I aortic dissection

OBJECTIVES

The aim of this study is to evaluate the locational impact of a luminal communication on aortic diameter changes and reintervention after surgical repair of acute type I aortic dissection.

METHODS

Between 2009 and 2017, 304 patients underwent operation for acute type I aortic dissection. Among them, 93 patients were enrolled. The luminal communications were analysed in segment 1 (the proximal descending thoracic aorta), segment 2 (the distal descending thoracic aorta) and segment 3 (the abdominal aorta). The aortic diameter was measured at the pulmonary artery bifurcation, coeliac axis, maximal abdominal aorta and maximal thoraco-abdominal aorta using serial follow-up computed tomography scans. The linear mixed model was used, and the rate of freedom from reintervention was analysed.

RESULTS

In the adjusted analysis, the initial diameter of the maximal abdominal aorta and the first luminal communication in segment 1 was statistically significant. However, the slope value of the maximal abdominal aorta was smaller than that of the first luminal communication in segment 1 (0.024 vs 0.198). The 3-year freedom from reintervention rate was significantly higher in patients without a luminal communication than in those with an initial luminal communication in segment 1 (96% vs 47%, log rank, P = 0.003).

CONCLUSIONS

A luminal communication at the proximal descending thoracic aorta (segment 1) is a significant factor for an increasing aortic diameter and reintervention after surgical repair of acute type I aortic dissection.

Comparison of dynamic changes in aortic diameter during the cardiac cycle measured by computed tomography angiography and transthoracic echocardiography

OBJECTIVE

This study aimed to examine the relationship between dynamic changes in aortic diameter and corresponding measurement methods.

METHODS

Consecutive adult (nonaneurysmal) patients being surgically treated for heart disease (mean age, 51 ± 11 years; range, 29-76 years; N = 25) were included in this study. All patients underwent transthoracic echocardiography (TTE), computed tomography angiography (CTA), and intraoperative ultrasound (IOUS). Anteroposterior diameters were measured at 1 cm above the junction of the aortic sinus, the proximal 1 cm of the innominate artery, and the midpoint of the two.

RESULTS

The average diameter of the proximal ascending aorta in systole/diastole measured by IOUS was 32.07 ± 2.03/30.27 ± 2.05 mm (paired t-test: difference, 1.80 ± 0.46 mm; P < .001). The average diameters of the proximal ascending aorta measured by nonelectrocardiography-gated CTA and TTE were 31.45 ± 1.97 mm and 29.7 ± 1.84 mm, respectively. The average diameter of the mid and distal ascending aorta in systole/diastole measured by IOUS was 32.35 ± 1.95/30.57 ± 1.94 mm (paired t-test: difference, 1.78 ± 0.44 mm; P < .001) and 32.32 ± 1.92/30.67 ± 1.90 mm (paired t-test: difference, 1.65 ± 0.42 mm; P < .001), respectively. The average diameter of the mid and distal ascending aorta measured by CTA was 31.74 ± 1.92 mm and 31.59 ± 1.96 mm, respectively. At each location, the difference in the aortic diameter between systole and diastole was statistically significant (all P values <.001; paired t-test). The minimum and maximum changes in the diameter between systole and diastole were 0.90 mm and 2.70 mm. In all, 96% (24/25) of the average diameters derived from IOUS and CTA at the three locations were within the concordance limit in systole, and 92% to 100% (23/25 to 25/25) were within the concordance limit in diastole. The average diameters derived from IOUS and TTE images of the proximal ascending aorta were within the bounds of the concordance limit 92% (23/25) of the time in systole and 100% (25/25) of the time in diastole. The average diameters derived from CTA and TTE images of the proximal ascending aorta were within the bounds of the concordance limit 88% (22/25) of the time. Pearson correlation coefficients between these groups ranged from 0.905 to 0.982 (all P values <.01).

CONCLUSIONS

The ascending aorta diameters measured by nonelectrocardiography-gated CTA and TTE were consistent with the IOUS measurements.

Value of N-terminal pro-brain natriuretic peptide and aortic diameter in predicting in-hospital mortality in acute aortic dissection

OBJECTIVE

To determine the value of N-terminal pro-brain natriuretic peptide (NT-proBNP) and aortic diameter in predicting in-hospital mortality in acute aortic dissection (AD).

METHODS

A single-center prospective study was designed in the setting of University hospital in China. 122 patients with acute AD were enrolled. Admission plasma NT-proBNP levels and aortic diameter were measured.

RESULTS

Plasma NT-proBNP concentrations (P < 0.001), aortic diameter (P = 0.002), and admission systolic blood pressure (SBP) (P = 0.011) were significantly increased in patients who died compared to those who survived during hospitalization. Furthermore, aortic diameter had positive correlations with NT-proBNP levels (r = 0.270, P = 0.003) and admission diastolic blood pressure (DBP) (r = 0.202, P = 0.025), respectively. Multiple logistic regression analysis demonstrated that NT-proBNP ≥569.75 pg/ml and aortic diameter ≥40 mm were strongly associated with in-hospital mortality. The odds ratio (OR) and 95% confidence interval (CI) were 3.246, 1.212-8.693 (P = 0.019); and 2.917, 1.102-7.722 (P = 0.031), respectively. Moreover, when NT-proBNP ≥1325.6 pg/ml, the sensitivity and specificity of NT-proBNP in predicting in-hospital mortality risk were 55.2% and 95.7% (95% CI, 0.707-0.891; P < 0.001), respectively. In addition, when aortic diameter ≥47 mm, the sensitivity and specificity were 58.6% and 88.2% (95% CI, 0.607-0.841; P < 0.001), respectively.

CONCLUSIONS

NT-proBNP ≥569.75 pg/ml and aortic diameter ≥40 mm were important risk factors and independently associated with acute AD in-hospital mortality. NT-proBNP ≥1325.6 pg/ml or aortic diameter ≥47 mm showed higher specificity in predicting in-hospital mortality. Using NT-proBNP and aortic diameter together showed better performance in predicting in-hospital mortality with higher sensitivity.

Current evidence in predictors of aortic growth and events in acute type B aortic dissection

OBJECTIVES

Acute type B aortic dissection can have a stable course or evolve into aneurysm and subsequent adverse events. The aim of this systematic review was to analyze the morphologic predictors of an adverse course to establish their validity based on consistency of results.

METHODS

Fifty-one studies were included in this review, reporting on aortic size, false lumen (FL) size, primary entry tear (ET) size and location, status of FL thrombosis, number of ETs, branch vessels involvement, and FL longitudinal extent.

RESULTS

Some predictors showed good consistency, whereas others did not. Aortic size was the most investigated predictor. A larger diameter at presentation predicted worse outcomes, with few exceptions. Both FL size and size relative to true lumen size also predicted an adverse course, although a standardized measurement method was not used. Regarding primary ET size and location, evidence was sparse and somewhat conflicting. Although FL complete thrombosis was consistently associated with a more benign course, the role of partial thrombosis remained unclear and the concept of FL saccular formation might account for the inconsistency, but further evidence is needed. A higher number of re-entry tears was considered to be protective against false channel expansion, but results need to be confirmed. The predictive role of branch vessels involvement and FL longitudinal extent remain controversial.

CONCLUSIONS

Among several predictors of aortic growth and events in acute type B aortic dissection, controversial and even conflicting results have been described. Consistent evidence has been demonstrated only for two predictors: aortic size at presentation is associated with adverse events and total FL thrombosis has a protective role.

Pregnancy outcome in Turner syndrome: A French multi-center study after the 2009 guidelines

OBJECTIVE

This study aimed to assess the application of the French guidelines for pregnancies in Turner syndrome (TS) and their impact on perinatal prognosis.

STUDY DESIGN

We performed a French multi-center retrospective study (14 centers), including TS pregnant patients (spontaneously or by Assisted Reproductive Technology (ART)) between January 2006 and July 2017. Only clinical pregnancies were analyzed. The adjustment of medical follow-up modalities to French guidelines was evaluated for all pregnancies after 2009. Pregnancies from oocyte donation (OD) after 2009 were compared to those of a cohort of TS pregnancies obtained by OD before 2009, which were reported by the French Study Group for Oocyte Donation.

RESULTS

One hundred seventy pregnancies in 103 patients were included: 35 spontaneous, 5 by means of intra-conjugal ART, and 130 with OD. No serious maternal complications were observed. We reported two stillbirths and one intra uterine fetal death. The French guidelines were partially respected. The preconceptional assessment was carried out in 74% of cases. Cardiology follow-up during pregnancy was performed in accordance with guidelines in 74% of patients. Postpartum cardiac ultrasonography was performed in 45% of pregnancies but only in 11% within 8 days post-partum. When compared to the 2009 historical cohort, the rates of high blood pressure (19% vs. 38%; p < 0.005) pre-eclampsia (8% vs. 21%; p < 0.005) and prematurity <35 weeks (15% vs 38%; p < 0.0001) were lower.

CONCLUSIONS

The implementation of guidelines has allowed the standardization of TS pregnancy care and improved perinatal indicators for both mothers and children. However, an effort must be done, in a postpartum survey.

Sex- and Age-Related Reference Values in Cardiology, with Annotations and Guidelines for Interpretation

The definition of "abnormal" in clinical sciences is often based on so-called reference values which point to a range that experts by some sort of consensus consider as normal when looking at biological variables. Such a level is commonly calculated by taking (twice) the standard deviation from the mean, or considering certain percentiles. The suspicion or even confirmation of a disease is then established by demonstrating that the value measured exceeds the upper or lower reference value. As is often the case, the measurement accuracy may depend on the conditions and specific method employed to collect and analyze data. This implies that, for example, data assessed by 2D echocardiography possibly differ from those obtained by MRI and therefore require modality-specific reference values. In this review we summarize reference values for the electrocardiogram, cardiac compartmental volumes, and arterial vessel size in males and females for various age groups. These values may further depend on other variables such as body size, physical training status, and ethnicity. Additional variables relevant for cardiology such as those referring to the microcirculation and biomarkers are only mentioned with reference to the pertinent literature. In general, the sex- and age-specific differences observed are often remarkable and warrant consideration in clinical practice and basic biomedical sciences.

Familial intracranial aneurysm, the relationship of the aortic diameter

OBJECTIVES

Familial predisposition appears as an identified risk factor for cerebrovascular disease. The primary objective of our study was to assess intracranial aneurysm (IA) recurrence rate in a population of familial IA. Secondary objectives were first to analyse the inheritance categorisation/pattern of these families and second to assess the correlation between the aortic diameter on MRI and the aneurysmal characteristics.

PATIENTS AND METHODS

Over a period of 20 years (1990-2010), 26 patients from 23 families, identified from a regional register, accepted to participate in this prospective trial in order to determine, the inheritance pattern, the screening of de novo aneurysms by CT angioscan, and the aortic mensuration by MRI. The transmission pattern was categorised into autosomal dominant inheritance, autosomal recessive and autosomal dominance with incomplete penetrance. The aortic diameter was measured: anatomic coverage in the caudo-cranial direction from the iliac arteries to the ventriculo-aortic junction.

RESULTS

All 26 patients [from 55.4 ± 11.2 years, sex ratio female/male: 1.36] were reviewed after a mean follow-up of 7.9 ± 6.6 years after the diagnosis of a cerebral aneurysm. The characteristics of this population were the diagnostic circumstances such as a subarachnoid hemorrhage (SAH) in 14 (53.8%), the multiple locations in 10 (38.5%) and a giant aneurysm in 4 (15.4%). Four de novo aneurysms were diagnosed in 3 patients (11.5%) after a mean follow-up of 22.3 ± 4 years, which corresponds to an annual incidence of 1.9 (95% CI 1.4-2.6%). The transmission pattern was autosomal dominant in 16 (61.5%), recessive in 3 (11.5%) and not defined in 7 (26.9%). As regards the aortic diameter, a significant decrease in the aortic diameter was observed in patients with an aneurysmal diameter superior to 10mm.

CONCLUSION

The rate of de novo aneurysm justifies prolonged monitoring by imaging of these patients with familial intracranial aneurysm. The narrowing of the terminal part of the aorta could be a hemodynamic factor involved into the IA development.

Association of Resting Heart Rate with Infrarenal Aortic Diameter: A Cross Sectional Study in Chinese Hypertensive Adults

OBJECTIVE

Elevated resting heart rate (RHR) has been shown to be a risk marker for cardiovascular disease. Results from studies on the effects of RHR in large arteries are limited to the functional changes of those arteries, while the association between RHR and aortic diameter remains largely understudied.

METHODS

This was a cross sectional study of hypertensive Chinese adults from rural areas. The maximum infrarenal aortic diameter (maxIAD) from renal arteries to the iliac bifurcation was obtained by ultrasound. MaxIADs in different RHR groups were compared in males and females separately because of the significant differences between sexes. Multiple regression analysis was used to determinate the correlation between RHR and maxIAD. Further interactions between three factors (BMI, smoking, and anti-hypertensive regimens) and RHR for maxIAD were examined using subgroup analysis.

RESULTS

19,200 subjects were enrolled in the study, with an average age of 64.8±7.4 years and 61.6% females. Only 22 cases (0.11%) were detected with AAA, with males (n = 17) presenting a higher AAA incidence than females (n = 5). In subjects ≥65 years, there were 18 (0.19%) AAA, and 15 (83.3%) had a history of smoking. In the total subjects, the mean maxIAD ranged from 15.7±2.1 mm to 15.2±2.2 mm as RHR changed from the lowest quartile to the highest (≥84 bpm) in males, with a similar tendency observed in females. The correlation coefficient of RHR on maxIAD was -0.17 in males and -0.12 in females. Further subgroup analysis revealed that smoking exaggerated the correlation between RHR and maxIAD, but only in females.

CONCLUSIONS

A low AAA incidence was observed in this hypertensive Chinese population. There was a negative association between RHR and maxIAD, potentially exaggerated by smoking, especially in females.

Thoracic and abdominal aortic diameters in a general population: MRI-based reference values and association with age and cardiovascular risk factors

OBJECTIVES

To generate reference values for thoracic and abdominal aortic diameters determined by magnetic resonance imaging (MRI) and analyse their association with cardiovascular risk factors in the general population.

METHODS

Data from participants (n = 1759) of the Study of Health in Pomerania were used for analysis in this study. MRI measurement of thoracic and abdominal aortic diameters was performed. Parameters for calculation of reference values according to age and sex analysis were provided. Multivariable linear regression models were used for determination of aortic diameter-related risk factors, including smoking, blood pressure (BP), high-density lipoprotein cholesterol (HDL-C).

RESULTS

For the ascending aorta (β = -0.049, p < 0.001), the aortic arch (β = -0.061, p < 0.001) and the subphrenic aorta (β = -0.018, p = 0.004), the body surface area (BSA)-adjusted diameters were lower in men. Multivariable-adjusted models revealed significant increases in BSA-adjusted diameters with age for all six aortic segments (p < 0.001). Consistent results for all segments were observed for the positive associations of diastolic BP (β = 0.001; 0.004) and HDL (β = 0.035; 0.087) with BSA-adjusted aortic diameters and for an inverse association of systolic BP (β = -0.001).

CONCLUSIONS

Some BSA-adjusted median aortic diameters are smaller in men than in women. All diameters increase with age, diastolic blood pressure and HDL-C and decrease as systolic BP increases.

KEY POINTS

• Median aortic diameter increases with age and diastolic blood pressure. • Median aortic diameter is larger in men than in women. • Some BSA-adjusted median aortic diameters are smaller in men than in women.

Using The Descending Aortic Wall Thickness Measured In Transesophageal Echocardiography As A Risk Marker For Aortic Dissection

OBJECTIVE

The aim of this study is to estimate whether aortic wall thickness is increased in patients with Aortic dissection (AD) compared to low risk control group and can be used in addition to aortic diameter as a risk marker of AD.

BACKGROUND

AD occurs due to pathologies that may increase thickness of the aortic wall. Transesophageal echocardiography (TEE) has the ability to visualize both the thoracic aortic wall and lumen. Aortic diameter has been used to predict aortic dissection and timing of surgery, but it is not always predictive of that risk.

METHODS

In 48 patients with AD who underwent TEE were examined retrospectively and compared to 48 control patients with patent foramen ovale (PFO). We measured aortic diameter at different levels, intimal/medial thickness (IMT) and complete wall thickness (CMT). Demographic data and cardiovascular risk factors were reviewed. The data was analyzed using ANOVA and student t test.

RESULTS

(AD) patients were older [mean age 66 AD vs. 51 PFO], had more hypertension, diabetes, hyperlipidemia and Coronary artery disease. Both IMT and CMT in the descending aorta were increased in AD group [(1.85 vs. 1.43 mm; P=0.03 and 2.93 vs. 2.46 mm; p=0.01). As expected the diameter of ascending aorta was also greater in AD (4.61 vs. 2.92 cm; P=0.004).

CONCLUSIONS

CMT and IMT in the descending aorta detected by TEE is greater in patients with AD when compared to control and may add prognostic data to that of aortic diameter.

Plasma levels of cathepsins L, K, and V and risks of abdominal aortic aneurysms: a randomized population-based study

BACKGROUND

Cathepsin L (CatL), cathepsin K (CatK), and cathepsin V (CatV) are potent elastases implicated in human arterial wall remodeling. Whether plasma levels of these cathepsins are altered in patients with abdominal aortic aneurysms (AAAs) remains unknown.

METHODS AND RESULTS

Plasma samples were collected from 476 male AAA patients and 200 age-matched male controls to determine CatL, CatK, and CatV levels by ELISA. Student's t-test demonstrated significantly higher plasma CatL levels in AAA patients than in controls (P < 0.0001), whereas CatK and CatV levels were lower in AAA patients than in controls (P = 0.052, P = 0.025). ROC curve analysis confirmed higher plasma CatL levels in AAA patients than in controls (P < 0.001). As potential confounders, current smoking and use of angiotensin-converting enzyme (ACE) inhibitors, aspirin, clopidogrel, and statins associated with significantly increased plasma CatL. Pearson's correlation test demonstrated that plasma CatL associated positively with CatS (r = 0.43, P < 0.0001), body-mass index (BMI) (r = 0.07, P = 0.047) and maximal aortic diameter (r = 0.29, P < 0.001), and negatively with lowest measured ankle-brachial index (ABI) (r = -0.22, P < 0.001). Plasma CatL remained associated positively with CatS (r = 0.43, P < 0.0001) and aortic diameter (r = 0.212, P < 0.001) and negatively with ABI (r = -0.10, P = 0.011) after adjusting for the aforementioned potential confounders in a partial correlation analysis. Multivariate logistic regression analysis indicated that plasma CatL was a risk factor of AAA before (odds ratio [OR] = 3.04, P < 0.001) and after (OR = 2.42, P < 0.001) the same confounder adjustment.

CONCLUSIONS

Correlation of plasma CatL levels with aortic diameter and the lowest ABI suggest that this cysteinyl protease plays a detrimental role in the pathogenesis of human peripheral arterial diseases and AAAs.