Popliteal vein compression, obesity, and chronic venous disease.

BACKGROUND: Obesity is a known risk factor for the development of chronic venous disease (CVD). However, some obese patients with lower limb skin changes suggestive of venous disease do not demonstrate venous reflux or obstruction. Popliteal vein compression (PVC) caused by knee hyperextension during standing has been postulated by others to be more common in the obese due to the increased adipose content of the popliteal fossa. This compression may contribute to the development of venous disease. The objective was to examine the prevalence of PVC in obese and nonobese subjects, with and without venous disease. METHODS: Participants were recruited across the range of Clinical-Etiology-Anatomy-Pathophysiology (CEAP) clinical classifications and body mass. Those referred for venous studies had full venous ultrasound assessments. To assess for PVC, the popliteal vein was assessed via B-mode ultrasound whilst the subject stood and performed two maneuvers: knee hyperextension and a bilateral toe stand. Video clips of each maneuver were analyzed offline. RESULTS: There were 309 limbs (158 subjects), of which 131 were nonobese (body mass index [BMI]: 26 ± 3 kg/m2) and 178 obese (BMI: 43 ± 8 kg/m2). PVC with toe stand (PVC(toe stand)) was more common in obese limbs (89% vs 64%, P < .001). It occurred mainly in the distal popliteal vein, associated with contraction of the gastrocnemius muscles. PVC with knee hyperextension (PVC(lock)) was also more frequent in obese limbs (39% vs 10%, P < .0001) and was distinct as it occurred more proximally in the popliteal vein. PVC(lock) was significantly more frequent in all C classes of obese patients, most notably in the obese with C4-6 CVD (41% vs 4%, P < .0001), and was associated with more severe Venous Clinical Severity Score (median 8 [range: 0-19] vs 5 [0-21], P = .034). There were 19 limbs with skin changes (C4-6) with no venous reflux or obstruction on ultrasound, exclusively obese limbs. These limbs, designated CEAP Pn limbs, were in older, shorter participants with a higher BMI than their counterparts demonstrating reflux, and they also had more frequent PVC(lock) (63% vs 37%, P = .036). CONCLUSIONS: PVC(toe stand) and PVC(lock) are both functional effects and more common in obese limbs. PVC(toe stand) is likely associated with normal functioning of the calf muscle pump. Although PVC(lock) may contribute to CVD in some obese limbs, the demonstration of PVC(lock) alone is insufficient evidence for direct intervention.

The clinical implications of adopting new criteria for the grading of internal carotid artery stenosis.

INTRODUCTION: A patient's eligibility for carotid endarterectomy (CEA) is determined primarily by the degree of carotid stenosis detected on duplex ultrasound. The Australasian Society for Ultrasound in Medicine (ASUM) criteria are widely used to grade carotid stenoses in many practices throughout Australasia. METHODS: We sought to investigate the potential impact on the grading of carotid artery stenosis if practitioners switched from the ASUM criteria to the United Kingdom's joint recommendation (UKJR) criteria by reviewing 100 patients with a haemodynamically significant carotid artery stenosis. RESULTS: We found agreement between the criteria in 100% of cases for stenoses <50%, in 80% of cases for stenoses 50-69%, in 89% of cases for stenoses ≥70% and in 100% of cases for stenoses ≥80%. While there was variation in grading of stenoses in 16% of cases, reclassification resulted in no change in the number of patients eligible for CEA. The UKJR guideline enabled more precise categorisation of haemodynamically significant stenosis into deciles. DISCUSSION: Because the UKJR guideline is more comprehensive, we believe that adopting this guideline would enable the ultrasound practitioner to grade carotid stenoses more precisely, better understand the nuances of carotid duplex imaging and more successfully navigate and interpret complex carotid examinations, without impacting the number of patients eligible for CEA.

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.

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.