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.

Meta-Analysis of Genome-Wide Association Studies for Abdominal Aortic Aneurysm Identifies Four New Disease-Specific Risk Loci.

RATIONALE: Abdominal aortic aneurysm (AAA) is a complex disease with both genetic and environmental risk factors. Together, 6 previously identified risk loci only explain a small proportion of the heritability of AAA. OBJECTIVE: To identify additional AAA risk loci using data from all available genome-wide association studies. METHODS AND RESULTS: Through a meta-analysis of 6 genome-wide association study data sets and a validation study totaling 10 204 cases and 107 766 controls, we identified 4 new AAA risk loci: 1q32.3 (SMYD2), 13q12.11 (LINC00540), 20q13.12 (near PCIF1/MMP9/ZNF335), and 21q22.2 (ERG). In various database searches, we observed no new associations between the lead AAA single nucleotide polymorphisms and coronary artery disease, blood pressure, lipids, or diabetes mellitus. Network analyses identified ERG, IL6R, and LDLR as modifiers of MMP9, with a direct interaction between ERG and MMP9. CONCLUSIONS: The 4 new risk loci for AAA seem to be specific for AAA compared with other cardiovascular diseases and related traits suggesting that traditional cardiovascular risk factor management may only have limited value in preventing the progression of aneurysmal disease.

Correcting for Body Surface Area Identifies the True Prevalence of Abdominal Aortic Aneurysm in Screened Women.

OBJECTIVE: Recently, the prevalence of abdominal aortic aneurysm (AAA) using screening strategies based on elevated cardiovascular disease (CVD) risk was reported. AAA was defined as a diameter ≥30 mm, with prevalence of 6.1% and 1.8% in men and women respectively, consistent with the widely reported AAA predominant prevalence in males. Given the obvious differences in body size between sexes this study aimed to re-evaluate the expanded CVD risk based AAA screening dataset to determine the effect of body size on sex specific AAA prevalence. METHODS: Absolute (26 and 30 mm) and relative (aortic size index [ASI] equals the maximum infrarenal aorta diameter (cm) divided by body surface area (m2), ASI ≥ 1.5) thresholds were used to assess targeted AAA screening groups (n = 4115) and compared with a self reported healthy elderly control group (n = 800). RESULTS: Male AAA prevalence was the same using either the 30 mm or ASI ≥1.5 aneurysm definitions (5.7%). In females, AAA prevalence was significantly different between the 30 mm (2.4%) and ASI ≥ 1.5 (4.5%) or the 26 mm (4.4%) thresholds. CONCLUSION: The results suggest the purported male predominance in AAA prevalence is primarily an artefact of body size differences. When aortic size is adjusted for body surface area there is only a modest sex difference in AAA prevalence. This observation has potential implications in the context of the ongoing discussion regarding AAA screening in women.

Novices may be trained to screen for abdominal aortic aneurysms using ultrasound.

BACKGROUND: Highly trained vascular sonographers make up a significant cost of abdominal aortic aneurysm (AAA) ultrasound screening. However, they are over-trained for this very limited task. Others have reported that health workers (e.g. emergency room staff and nurses) with far less training may be able to perform these scans. The national AAA screening programme in the UK uses staff with limited training. Whether individuals without a health professional qualification could be trained to perform the scan accurately to improve cost-effectiveness is not known. We aimed to investigate whether a short, well-supervised course in ultrasonography could train novices to detect AAA for screening purposes. METHODS: Three novices were trained by an experienced sonographer for 15 days to perform abdominal aortic ultrasound examinations and detect AAA using a portable ultrasound system. The examination included four anterior-posterior aortic measurements: a maximal diameter in the coronal plane and three diameters of the suprarenal, mid and distal infrarenal aorta in the transverse plane. The novices independently scanned 215 subjects following training; experienced sonographers repeated the measurements on the same subject in the same session. Using Bland-Altman plots and CUSUM analysis, the novices' and experienced sonographers' accuracy and efficiency measurements were compared. Factors influencing performance were recorded. RESULTS: The novices measured the maximal coronal aortic diameter accurately, to within 0.46-0.52 cm of the true diameter; 85-97% of their coronal measurements were within 0.5 cm of the assessors; kappa statistic and Bland-Altman plots show a high agreement with the assessor's measurements. However, the novices' measurements of the three diameters in the transverse plane were outside clinically acceptable limits. Assuming a referral policy for a second scan for scans recorded as 'difficult', only one novice missed a 3.13 cm aneurysm.A CUSUM quality improvement analysis demonstrated substantial improvements in the scanning efficiency of the novices with continued scanning experience. CONCLUSION: This study showed that novices could be trained to screen for AAA over 15 days. However, the need for continuing quality improvement is critical, especially in more technically demanding cases. Measuring the maximal infrarenal diameter instead of specific segmental diameters may be more appropriate for AAA screening using novices.

Failure of microvenous valves in small superficial veins is a key to the skin changes of venous insufficiency.

OBJECTIVE: To determine the role of microvenous valves in the superficial venous system in the prevention of reflux and skin changes in the progression of venous insufficency. METHODS: The venous anatomy of 15 amputated lower limbs, eight free from clinical venous disease and seven with varicose veins and ulcers, was examined using retrograde venography corrosion casting. Prior to amputation, all limbs were scanned by duplex ultrasound to confirm the presence or absence of reflux in the great (GSV) and small saphenous veins or their tributaries. The resulting resin casts were photographed and mapped to show the position, orientation, and competency of valves in the superficial venous network. Casts were also examined by scanning electron microscopy. RESULTS: Retrograde venous filling was demonstrated in the "normal" limbs despite a competent GSV. Microvalves were identified down to the sixth generation of tributaries from the GSV. Only in regions where incompetence existed in microvalves out to the third (ie, the "boundary") generation was the resin able to penetrate deeper into microvenous networks of the dermis. This was despite the presence of subsequent competent valves, which were able to be bypassed in the network. In limbs with varicose veins and venous ulcers, reflux into the small venous networks and capillary loops was more extensive with more dense networks and greater tortuousity. CONCLUSIONS: This study demonstrates that valvular incompetence can occur independently in small superficial veins in the absence of reflux within the GSV and the major tributaries. We have shown that once there is incompetence of the third generation "boundary" microvalves, reflux can extend into the microvenous networks in the skin. These effects are markedly worse in the presence of GSV incompetence. We propose that degenerative changes with valve incompetence are required in both the larger proximal vessels and the small superficial veins, in particular at the "boundary" valve level, for the severe skin changes in venous insufficiency to occur.

The natural history of ultrasound-detected recurrence in the groin following saphenofemoral treatment for varicose veins.

OBJECTIVE: This prospective study sought to track the natural history of duplex ultrasound (DUS) detected varicose vein recurrence in the groin after surgical intervention during a 5-year period. METHODS: Patients were recruited from a previous prospective trial investigating outcomes after high ligation and stripping with and without patch saphenoplasty. Follow-up examinations of the lower limb venous systems using DUS, air plethysmography, and clinical assessment were carried out at 1, 6, 12, and 36 months. At 60 months, an additional detailed DUS scan of the groin was performed on those with recurrence, including vessel numbers, diameter, and reflux velocity, to characterize the state of this groin recurrence. RESULTS: In the 130 limbs at 5 years, ultrasound groin recurrence was detected in 82%, and visible varicose veins occurred in 83% (108 limbs). In contrast, recurrence with severe varices occurred in 47% (61 limbs) as clinical recurrence (Venous Clinical Severity Score less the stocking component >3) in 22% (29 limbs) and functional recurrence (venous filling index >2 mL/s) in 34% (43/125 limbs). The DUS pattern was junctional in 29 limbs (22%), nonjunctional in 37 limbs (29%), and mixed pattern in 40 limbs (31%). Compared with the 24 (19%) with no ultrasound-detected recurrence, severe visible varicose veins were significantly more common with each of these patterns and especially with multiple connecting vessels (odds ratio, 5.4; confidence interval, 1.5-19.5). The diameter and velocity of reflux through recurrent vessels in the groin did not correlate with disease severity, and no DUS feature in the groin was predictive of Venous Clinical Severity Score >3 or a venous filling index >2 mL/s. The appearance of DUS recurrence within the first year and other features, including residual lower leg reflux, body mass index, gender, and previous treatment, were more consistent predictors. CONCLUSIONS: Early ultrasound recurrence is predominantly evidence of neovascularization and some small-vessel remodeling at the site of treatment. When it occurs, some visible varicose veins are inevitable. However, these appearances alone are not good predictors of severe clinical recurrence.