Is bilateral ultrasound scanning of the legs necessary for patients with unilateral symptoms of deep vein thrombosis?

PURPOSE: The purpose of this study was to determine the necessity of bilateral lower-extremity venous duplex ultrasound scanning in patients with unilateral symptoms of deep vein thrombosis (DVT). PATIENTS AND METHODS: A retrospective review of 1080 bilateral venous duplex scans was performed. Patients were randomly selected from a total of 7922 studied between May 1998 and May 2000. Data on patient age, sex, comorbidity, and the reason for ultrasound scan were compiled. Forty percent (435/1080) of patients presented with unilateral symptoms of lower-extremity DVT. This group was further analyzed according to their status as inpatients or outpatients. RESULTS: DVT was diagnosed in 26.9% (117/435) of the patients. Of the inpatients found to have DVT, the thrombus was confined to the symptomatic leg in 23.8% (38/159), thrombus was present just in the asymptomatic leg in 8/159 (5.0%), and thrombus was found in both legs in 8/159 (5.0%). In the outpatient group, thrombus was confined to the symptomatic leg in 21.0% (58/276) and found in both legs in 1.8% (5/276). None of the 276 outpatients had DVT isolated in the asymptomatic leg. CONCLUSION: Routine bilateral lower-extremity venous duplex studies are not necessary in outpatients presenting with unilateral symptoms. In many outpatients, a single-limb study will suffice. If a patient is found to have a DVT on the symptomatic side, then we believe that a bilateral study is indicated. We do believe that routine bilateral scanning of inpatients remains justified. This algorithm may save technician time and increase vascular laboratory efficiency.

Feasibility of transgastric ultrasonography of the abdominal aorta.

PURPOSE: Transesophageal echocardiography provides detailed images of the thoracic aorta, but imaging of the abdominal aorta and its branches does not occur routinely when the transesophageal echocardiography transducer is advanced into the stomach. Transgastric aortic ultrasonography (TAUS) was investigated as an intraoperative procedure to determine whether transgastric imaging of the abdominal aortic, mesenteric, and renal arteries could be obtained and whether pathologic lesions of these arteries could be identified. METHODS: Twelve patients with diagnoses of aortic aneurysmal or occlusive disease, chronic mesenteric ischemia, or renal artery stenosis that required operative treatment were examined. Preoperative transabdominal duplex imaging was performed in all 12 patients. Transgastric B-mode and color-flow ultrasonography of the abdominal aorta and branches was performed as an intraoperative procedure with the patients under general anesthesia. After the abdomen was opened but before the vascular reconstruction was performed, the transesophageal transducer was advanced into the stomach and directed by the surgeon's hand to obtain an image of the underlying aorta and branches. TAUS images were compared with those obtained by standard transabdominal duplex imaging. RESULTS: TAUS provided high-resolution images of both aneurysmal and occlusive aortic disease. In all 12 cases the images of the aortic lumen, plaque, and thrombus obtained with TAUS had greater detail and better resolution than those obtained with transabdominal duplex imaging. The origins of the renal arteries were seen with TAUS in 23 of 24 cases, whereas transabdominal ultrasonography obtained images of the origins in only 6 of 24 cases (p < 0.01). In the five renal arteries and the one mesenteric artery with hemodynamically significant stenoses in which transabdominal ultrasonography identified the stenoses based on velocity criteria alone, TAUS visualized the occlusive plaque at the origin of the renal and mesenteric arteries. CONCLUSION: Intraoperative TAUS is feasible and may be useful for evaluating atherosclerotic disease of the abdominal aorta and renal arteries.

Mesenteric flow velocity variations as a function of angle of insonation.

This study was designed to quantitate variations in duplex ultrasound arterial flow velocities (cm/sec) in the common carotid artery and the superior mesenteric artery that were produced by changes in the angle of pulsed Doppler insonation. Duplex scanning was used to measure peak systolic flow velocity and mean velocity at angles from 30 degrees to 80 degrees; individual measurements were made at 10-degree increments in both the common carotid artery and the superior mesenteric artery in normal subjects. Peak systolic velocity in the common carotid artery varied from 86 cm/sec at 30 degrees to 168 m/sec at 80 degrees. Over the same transducer angle variation mean velocity ranged from 28 to 53 cm/sec. Similar changes in the superior mesenteric artery flow velocities were observed by varying the angle of insonation, where peak systolic velocity varied from 108 cm/sec (30 degrees) to 280 cm/sec (80 degrees), and mean velocity ranged from 29 cm/sec (30 degrees) to 71 cm/sec (80 degrees). Measurements taken from 70 to 80 degrees produced the most dramatic deviation from those taken at 60 degrees. In the common carotid artery the 70- and 80-degree angles produced 14% and 59% increases, respectively, in peak systolic velocity and 16% and 63% increases, respectively, in mean velocity. In the superior mesenteric artery 70-degree and 80-degree angles produced 16% and 120% increases, respectively, in peak systolic velocity and 17% and 111% increases, respectively, in mean velocity. At 80 degrees the percent increases in measured flow velocities for the superior mesenteric artery were significantly greater than those for the common carotid artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Duplex assessment of the renal transplant.

Duplex scanning is an inexpensive, noninvasive method of following renal transplant function. It can accurately define degrees of renal artery stenosis, and it can identify perirenal and perivascular fluid collections. Duplex scanning can provide less-specific information regarding changes in intrarenal vascular impedance that can assist in the diagnosis of acute rejection. It is an important initial method for following patients after renal transplantation.

Duplex ultrasound measurement of changes in mesenteric flow velocity with pharmacologic and physiologic alteration of intestinal blood flow in man.

Duplex ultrasound scanning has been used to assess mesenteric blood flow in normal and disease states. To investigate this technique we studied nine normal volunteers at rest and under conditions known to modify intestinal blood flow. After a baseline mesenteric duplex scan, each subject was given one of three treatments in random order: (1) test meal (710 kcal), (2) intravenous glucagon (40 micrograms/min), or (3) intravenous vasopressin (0.2 units/min). Peak systolic and diastolic velocities and vessel diameters were measured at intervals after treatment in the celiac and the superior mesenteric arteries (SMAs) and the right common carotid artery. Resting velocities did not differ among the groups. Peak systolic velocity increased significantly in both celiac and SMAs after the meal, with maximal changes in the celiac artery preceding those in the SMA in most subjects. Early diastolic flow reversal in the SMA was consistently lost after the meal (eight of nine subjects). Velocity changes after glucagon closely paralleled those after the meal. Vasopressin produced significant decreases in peak systolic velocity in both visceral vessels. No changes in vessel diameter were noted after any treatment. Coefficient of variation for repeated measures of peak velocities was 19% in the celiac and 12% to 16% in the SMA and the common carotid. The coefficient of variation for repeated measurements of arterial diameter was 6% to 8% in the SMA and 11% in the celiac artery. Clinically relevant changes in mesenteric hemodynamics can be reproducibly detected and quantitated by means of current duplex ultrasound technology. The similarities between the visceral arterial responses to a meal and glucagon are of interest.(ABSTRACT TRUNCATED AT 250 WORDS)