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Notes: Abstract Noninvasive tests for deep venous thrombosis (DVT) are helpful in evaluating patients with suspected pulmonary embolism (PE) who have non-high-probability ventilation/perfusion (V/Q) lung scans. Based on the enthusiasm for these noninvasive tests, venous duplex imaging (VDI) has evolved as the initial screening test for patients with clinically suspected PE in some centers. This study evaluates the utility of VDI as the initial test in a diagnostic algorithm for patients with suspected PE. A total of 306 consecutive patients who underwent VDI as the initial screening test for clinically suspected PE during the past 24 months were reviewed; 121 patients were subsequently evaluated with V/Q scans and 20 underwent pulmonary arteriography. VDI demonstrated DVT in 10% (23/216), with 7% (22/306) having proximal DVT and 3% (9/306) having isolated calf DVT. In 25 patients with unilateral leg symptoms, DVT was found in 40% (10/25); however, among the 281 without unilateral leg symptoms, results of VDI were abnormal in only 5% (15/281). V/Q scans were obtained in 40% (121/306), with only 16% (19/121) of scans showing a high probability of PE. DVT was found in 25% (5/19) of patients with high-probability V/Q scans and in 25% (26/102) with non-high-probability scans. In patients with clinically suspected PE the incidence of detectable infrainguinal DVT is low. VDI appears to be a reasonable initial screening test in patients with clinically suspected PE and unilateral leg symptoms. However, in patients without unilateral leg symptoms, the diagnostic yield is low and an alternative diagnostic approach appears justified.

Notes: venoarterial reflex (VAR) restricts arterial inflow, and avoids an excessive rise in capillary pressure. This study tests the hypothesis that there is microcirculatory compensation to atherosclerotic disease of increasing severity. Foot skin perfusion (FSP) was measured in 100 limbs with a laser Doppler placed on the plantar aspect of the great toe. Limbs were categorized as normal (n= 31) with an ankle brackial index (ABI) ≥ 0.96, claudicants (n= 42) ABI 0.5–0.86, and critical ischemia (n= 27) with an ABI 〈*leq〉 0.49 or a pulse volume recording consistent with severe peripheral vascular disease and symptoms of rest pain or tissue loss. Segmental Doppler pressures and pulse volume recordings were performed prior to laser Doppler measurements. Subjects with clinical signs or symptoms of chronic venous insufficiency were excluded. The resting foot skin perfusion was measured in the horizontal and dependent position, with the patient supine and sitting. Comparisons within categories were done using Wilcoxon matched pairs signed rank test and between groups with Mann–Whitney U test for unpaired data. Differences were considered significant if they exceeded the 95% confidence level (p value 〈*leq〉0.05). Resting supine skin perfusion was similar between nondiabetic normals and claudicants and diabetic normals and claudicants. There was a significant decrease in the foot skin perfusion (mean FSP ± SEM) in the normal limb with a change from the supine (7.8 ± 2.2 ml/min/100 g) to the dependent (2.8 ± 0.6 ml/min/100 g) position indicating an intact VAR. This was absent in 33% of the limbs with claudication. Limbs with critical ischemia demonstrated an increase in FSP with dependency (supine 4.0 ± 1.0 ml/min/100 g) versus dependent (8.4 ± 1.8 ml/min/100 g) and was present in both diabetic and nondiabetic limbs. Microcirculatory compensation occurs early in atherosclerotic limbs. Although supine FSP is similar in normals and claudicants, a greater percentage of claudicants demonstrate a loss of the VAR. Critically ischemic limbs have increased FSP in the dependent position. These observations indicate that there are microcirculatory alterations in limbs with claudication and assist in explaining why patients with ischemic rest pain obtain relief and develop edema with dependency.