Journal for Vascular Ultrasound

Brachial artery flow-mediated dilation is a well-established technique in the noninvasive assessment of endothelial function. Endothelial dysfunction is thought to be a potential precursor of atherosclerosis. In this study we compared the electrocardiogram (ECG) R-wave-gated acquisition of brachial artery measurement versus averaged measurement throughout the cardiac cycle.

Cohort study: participant data was analyzed by use o the ECG-gated and nongated techniques and then analyzed.

Patients with peripheral vascular disease were studied. Upper limb ischemia was caused by inflating a blood pressure cuff at the right upper arm for 3 minutes. Brachial artery diameter measurements were taken in longitudinal section using a Sonosite Titan ultrasound machine with a 38 mm 5–10 MHz broadband linear array transducer.

Twenty-three participants were tested (10 lower limb claudicants and 13 healthy volunteers). There was good correlation between ECG R-wave gated and nongated measurement R² = 0.58 and Pearson's correlation coefficient was 0.762 (p < 0.0001). Bland and Altman's method demonstrated good agreement and no heteroscedastic error.

We suggest that the use of automated image acquisition and analysis throughout the cardiac cycle to be preferable to ECG-gated acquisition. This may be important in the design of clinical trials involving noninvasive assessment of endothelial function.

Vascular screening programs have been gaining popularity in recent years; however, most programs accept all patients willing to participate. This study was designed to determine the yield of disease when screening examinations are limited to those most at risk, to stratify the amount of disease present in the at-risk population, and to establish which patients might benefit most from vascular screening.

Patients enrolled in a community outreach program for seniors 55 years of age and older were asked to participate in a free vascular screening. Screenings consisted of completion of a questionnaire, physical examination, limited carotid artery evaluation for stenosis, aorta evaluation for detection of aneurysm, and ankle/brachial index (ABI) calculation to detect peripheral vascular disease. Findings were grouped into “Normal,” “Mild disease,” and “Significant disease.” Findings were then compared with the following controllable risk factors: hypertension, hyperlipidemia, diabetes, coronary artery disease (CAD), or smoking history.

Between May 16 and October 17, 2007, 357 participants' (75 male, 157 female, mean age 72.9 years) results were analyzed. Overall, 140 participants (43%) had some form of vascular disease (“mild” and “significant” categories combined). Of 324 eligible participants, carotid findings showed 199 normal (61%), 104 mild (32%), and 21 significant (7%) results. Aorta findings showed 296 normal (91%), 25 mild (8%), and 3 significant (1%) results. ABI findings showed 278 normal (86%), 18 mild (6%), and 28 significant (8%) results. In participants with three or more risk factors, there was a greater probability that carotid (p = 0.0022) and peripheral vascular disease (p = 0.0003) would be detected; however, there was no predictive value for aortic aneurysm (p = 0.5).

Vascular screening programs focusing on the at-risk population may reduce unnecessary testing compared with programs evaluating all patients willing to participate.

Aortic dissection limited to the abdominal aorta is not common. This case report describes the role of duplex ultrasound in the diagnosis of asymptomatic dissection of the abdominal aorta.

A 59-year-old man with hypertension and mild renal impairment was referred to the vascular laboratory for color ultrasound examination of the renal arteries to rule out renal arterial stenosis. The ultrasound examination revealed a nonsignificant (<60%) stenosis in the right renal artery and two thickened but patent left renal arteries; however, there was an incidental finding of dissection of the abdominal aorta arising from the level of the celiac trunk down into the iliac arteries. Magnetic resonance imaging of the thoracic and abdominal aorta was requested; contrast was not used in view of the patient's deteriorating renal function. The finding revealed no features to indicate dissection in the thoracic or abdominal aorta. In view of the discrepancy in findings, computed tomography aortogram was performed. Dissection of the abdominal aorta just distal to the origins of the renal arteries was seen. This case study details the high sensitivity of color ultrasound imaging in identifying abdominal aorta dissection.

Color duplex ultrasound may be operator dependent but it is a highly sensitive and cost effective modality for identifying abdominal aortic dissection.

Carotid artery dissection is an important cause of stroke in young adults. Because warning signs usually precede stroke, the timely diagnosis of carotid dissection can have a significant clinical impact. We present a case of spontaneous carotid artery dissection with dynamic findings on duplex ultrasound examination.

A 47-year-old man presented with acute neurologic symptoms. Carotid duplex ultrasound demonstrated a high resistive waveform in the right internal carotid artery (RICA) with absent end-diastolic flow (peak-systolic velocity [PSV] = 49 cm/sec, end-diastolic velocity = 0 cm/sec), a narrowing of the lumen in the distal RICA with low velocity flow (PSV = 10 cm/sec), and eventual loss of flow. The right common carotid artery demonstrated a high resistive waveform. The use of magnetic resonance angiography confirmed the presence of distal RICA dissection. The patient was treated with antiplatelet therapy and had marked clinical improvement within 48 hours. A duplex ultrasound study performed 24 hours after the first study demonstrated dramatic restoration of the diastolic flow in the RICA (PSV = 97 cm/sec, EDV = 44 cm/sec) with normalization of the Doppler waveforms. Repeat magnetic resonance angiography demonstrated near complete resolution of the RICA dissection, correlating with the ultrasound findings.

Our case demonstrates the potentially dynamic nature of carotid artery dissection and the utility of duplex ultrasound as an invaluable tool in the early diagnosis and management of this disorder. In addition, the case demonstrates the importance of carotid Doppler waveform clues as indirect evidence of more distal cerebrovascular disease that warrants further investigation.