Normal lower limb venous Doppler flow phasicity: is it cardiac or respiratory?

OBJECTIVE: The purposes of this study were to determine the origin and nature of normal lower limb venous Doppler flow phasicity and to assess normal and respiratory variations. SUBJECTS AND METHODS: The common femoral veins of 12 healthy volunteers (three men and nine women; age range, 21-50 years; mean, 29 years) were evaluated by detailed spectral Doppler examinations with simultaneous ECG and respirometric tracings. The examinations were performed using a 5- or 7-MHz linear-array transducer with breath held in mid respiration, at the end of deep expiration, at the end of deep inspiration, during Valsalva's maneuver, and during quiet and deep breathing. The tracing obtained during breath-hold in mid respiration was considered the baseline. Tracings obtained during the other respiratory phases were analyzed for changes from the baseline. Doppler tracings were analyzed for phasicity, waveform frequency, components, velocities, velocity ratios, and presence of retrograde flow, all in correlation with simultaneous ECG and respirometric tracings. Tracings were analyzed independently by two observers to assess interobserver variability. RESULTS: With breath-hold in mid respiration, the common femoral vein Doppler tracings consisted of multiphasic waveforms that had a frequency similar to that of the heart rate. Each waveform consisted of systolic, v, diastolic, and a waves. The systolic wave occurred 0.4 sec later than the QRS complex of the ECG and was always antegrade. The v wave was always retrograde without flow reversal. The diastolic wave was always antegrade. The a wave was always retrograde but showed flow reversal in nine of 12 subjects. The systolic:diastolic velocity ratio ranged from 0.9 to 1.5 (mean, 1.1). The minimum:maximum velocity ratio ranged from -0.4 to 0.2 (mean, -0.15). With breath-hold at the end of expiration, the waveforms became slightly damped, becoming biphasic in five subjects and remaining multiphasic in seven. With breath-hold at the end of inspiration, the waveforms became nonphasic or biphasic in nine and decreased in velocity in 12. With Valsalva's maneuver, flow stopped. With normal respiration, cardiac waveforms were modulated by higher amplitude and less frequent biphasic respiratory waves. The plasticity was equal in two, dominantly cardiac in six, and dominantly respiratory in four. Flow velocity increased with expiration and decreased with inspiration. With deep breathing, the respiratory waves further increased, while the cardiac ones decreased in amplitude. The latter continued to modulate the respiratory phasicity in 10 subjects. CONCLUSION: During quiet respiration, lower limb venous Doppler tracings consisted of both cardiac and respiratory waveforms. Although respiratory waveforms disappeared when patients held their breath, Doppler tracings continued to be multiphasic and cardiac. Therefore, cardiac phasicity in lower limb venous Doppler tracings does not necessarily indicate cardiac disease. Other respiratory phases can modulate this basic cardiac pattern. Decrease in or loss of phasicity in these waveforms does not always mean proximal obstruction, because it can be caused by respiratory factors. Finally, the presence of minimal cyclic retrograde flow that is 5 cm/sec or less does not necessarily indicate cardiac disease.

Spigelian hernia: diagnosis by high-resolution real-time sonography.

The purpose of this study was to demonstrate the role of high-resolution real-time sonography in the diagnosis of spigelian hernias. The sonographic findings in three patients, two of whom had surgical confirmation, are presented. We also discuss and demonstrate the anatomic and pathologic factors that predispose to these hernias. In all three cases, real-time high-resolution sonography was very helpful in providing detailed images of the abdominal wall defect, the hernial sac and contents, and the relationship of the contents to the spigelian fascia and the rectus, external oblique, and internal oblique muscles. The role of the Valsalva and other provocative maneuvers in demonstrating the "in and out" sliding movement of the contents of the hernia also is discussed. Although the number of cases in our study is small, we think that this modality may be the most effective means for establishing this diagnosis, especially in cases with equivocal clinical findings.

Pulsatile venous Doppler flow in lower limbs: highly indicative of elevated right atrium pressure.

OBJECTIVE: The purpose of this study was to determine if pulsatile flow in lower limbs as seen on venous Doppler waveforms correlates with increased right atrium pressure. MATERIALS AND METHODS: Of 429 patients who, over a 14-month period, underwent venous Doppler imaging of the lower limb to exclude deep venous thrombosis, 343 records were available for review at the time of the study. Of these, 74 had right atrium pressure measurements available for correlation. Seventeen patients were excluded because of thrombosis in the common femoral vein. Six other patients were also excluded because the time difference between the Doppler and the correlative studies was more than 4 weeks. The remaining 51 patients constituted the study subjects. In 18 of these, the right atrium pressure was measured within 1 week, 31 within 2 weeks, 42 within 3 weeks, and 51 within 4 weeks. In the study, we evaluated the three major veins of the lower limb (the common femoral, superficial femoral, and popliteal) by venous Doppler imaging. Data from only the common femoral vein were included in our analysis because this vessel was the least involved with thrombosis. The findings were correlated with the presence or absence of right-sided heart failure as determined by right atrium pressure measurement. A Doppler waveform was considered pulsatile when it had a cyclic retrograde component. A right atrium pressure of more than 8 mm Hg was considered elevated. RESULTS: Of 51 patients, 17 (33%) had pulsatile lower limb venous Doppler flow waveforms and 33 (65%) had elevated right atrium pressure. We found a statistically significant correlation between the presence of these abnormal waveforms and elevated right atrium pressure. The sensitivity of lower limb venous Doppler imaging for detecting right-sided heart failure as determined by right atrium pressure measurement was 46%, specificity was 94%, positive predictive value was 94%, negative predictive value was 50%, and accuracy was 65%. CONCLUSION: Pulsatile lower limb venous Doppler waveform correlates well with right-sided heart failure, as indicated by a right atrium pressure measurement of more than 8 mm Hg. However, because of its low sensitivity, lower limb venous Doppler imaging cannot be used to screen for right-sided heart failure.