Importance of Doppler analysis of transmitted atrial waveforms prior to placement of central venous access catheters.

PURPOSE: To assess the sensitivity of Doppler flow analysis of the axillary and internal jugular veins to screen for clinically occult thoracic central veno-occlusive disease and predict successful placement of central access catheters. MATERIALS AND METHODS: Sixty-seven patients underwent both duplex sonographic evaluation of the axillary and internal jugular veins and contrast venography prior to placement of a central venous catheter. Duplex evaluation included visual evidence of veno-occlusive disease as well as the presence or absence of normal transmitted polyphasic atrial waves and respiratory variation of flow. Diagnostically adequate venograms were available for comparison with the duplex sonograms in 168 access routes (access site plus downstream conduit veins). The contrast venograms and sonograms were compared by using retrospective blinded interpretation. Outcome of attempted catheter placement was tabulated. RESULTS: Directed sonographic imaging of the axillary and internal jugular vein allowed detection of access route veno-occlusive disease with a sensitivity of only 33.3%. Alternatively, when Doppler flow analysis found atrial waveforms that were not polyphasic, central conduit occlusive disease was detected with a sensitivity of 79.6%. Monophasic atrial waveforms were associated with a 25% failure rate of catheterization due to central vein occlusive disease, whereas polyphasic atrial waveforms were correlated with a 100% success rate for catheter placement. CONCLUSION: In asymptomatic patients, sonographic imaging alone misses most instances of central veno-occlusive disease. However, Doppler flow analysis of transmitted atrial waveforms substantially improved the sensitivity. A normal polyphasic atrial waveform virtually excludes the possibility of a more central venous occlusion or stenosis greater than 80% and ensures an adequate route for central venous catheterization.

Intraosseous venous drainage anomaly in patients with pretibial varices: imaging findings.

PURPOSE: To determine a set of distinctive imaging findings seen in symptomatic patients with pretibial varices. MATERIALS AND METHODS: Medical records and imaging studies of patients who presented with pretibial varices over an 8-year period were collected from four institutions. Findings in six symptomatic patients with pretibial varices were retrospectively reviewed. Radiographic and magnetic resonance (MR) imaging findings were available from all six patients; findings from several other modalities were also available in some patients. RESULTS: Conventional radiographs showed a small osteolytic defect in the anterior cortex of the midtibia and a prominent, longitudinally oriented, radiolucent groove in the proximal half of the tibial diaphysis. MR images showed pretibial varices connected to an enlarged vessel in the tibia that eventually exited through the nutrient foramen. Computed tomographic (three patients), sonographic (four patients), venographic (four patients), arteriographic (two patients), and surgical (three patients) findings demonstrated that these patients had an unusual intraosseous varix that traversed the anterior cortex, medullary cavity, and posterior cortex of the tibia. CONCLUSION: Recognition of these findings can prevent misdiagnosis and may prove helpful in the planning of appropriate treatment.

The superficial femoral vein. A potentially lethal misnomer.

OBJECTIVE: To assess the potential for error in interpretation of venous duplex reports that use the term "superficial femoral vein." DESIGN: Three surveys conducted by mail. SETTING: Three multispecialty medical groups, anatomy departments of all US medical schools, and vascular laboratories. PARTICIPANTS: A total of 46 family practitioners and general internists, 95 chairpersons of departments of anatomy, and 85 laboratory directors. MAIN OUTCOME MEASURES: Proposed treatment of a patient with leg pain and an acute thrombosis of the superficial femoral vein; what nomenclature(s) for the deep thigh veins is (are) felt to be correct, what are acceptable alternatives, what is taught to students and which is preferred; and what terminology is being used in lower limb venous duplex reports. RESULTS: Only 24% (11/46) of the respondents would have administered anticoagulants to the patient as described. Only 3% (3/95) of anatomists felt the term "superficial femoral vein" was correct, 22% (21/95) felt it was an acceptable alternative (though only 9% [9/95] taught it to medical students), and only 7% (7/95) of anatomists felt the term was preferred for everyday use. The term "superficial femoral vein" is used by 93% (79/85) of vascular laboratories in lower limb venous duplex reports. CONCLUSION: Although the overwhelming majority of vascular laboratories use the term "superficial femoral vein" in venous duplex reports, the use of this term is potentially hazardous to patients. Most primary care physicians have not been taught and are not aware that the superficial femoral vein is a deep vein and that acute thrombosis of this vessel is potentially life threatening.

An unusual variant of popliteal artery entrapment.

A 43-year-old woman presented with incapacitating exertional pain in the right foot, ankle, and lower calf of 1 years' duration following a minor ankle sprain. Evaluation by several physicians had been inconclusive. Physical examination identified normal pedal pulses at rest but obliteration of pulses with active plantar flexion. Segmental pressures were normal at rest and duplex scanning showed occlusion of the popliteal artery with active plantar flexion. The findings were confirmed by arteriography despite a normal course of the popliteal artery. Magnetic resonance imaging (MRI) showed no muscular abnormality. At exploration entrapment was noted to be the result of compression by branches of the sural nerve and vein as they coursed medially inserting into the medial head of the gastrocnemius muscle. Division of the neurovascular bundle resulted in complete resolution of symptoms and arterial compression on duplex examination postoperatively. This case was unusual because of the patient's age, sex, and the pathologic findings that had not been previously reported. In this case MRI was not useful in demonstrating a muscular or neurovascular bundle abnormality, supporting the use of duplex scanning as the noninvasive diagnostic modality of choice.

Nitroglycerin decreases medial smooth muscle cell proliferation after arterial balloon injury.

PURPOSE: Nitroglycerin and its effector molecules nitric oxide and cyclic guanosine monophosphate decrease smooth muscle cell proliferation in vitro. We examined the in vivo effect of nitroglycerin on intimal hyperplasia. METHODS: We treated rats after carotid artery balloon injury with nitroglycerin delivered paraarterially with a miniosmotic pump for 1 week. RESULTS: High nitroglycerin serum levels were achieved, and the level of cyclic guanosine monophosphate in the carotid artery wall was significantly increased (1.48 +/- 0.37 vs 0.86 +/- 0.39 pmol/mg protein; p < 0.05) in the nitroglycerin-treated group. Cellular proliferation in the arterial wall was assessed by incorporation of 5-bromo-2'-deoxyuridine 6 days after the injury and was lower in the nitroglycerin-treated group (15.2 +/- 3.4 vs 36.3 +/- 5.5 positive cells/section; p < 0.005). This was due to a decrease in the number of proliferating cells in the media (6.3 +/- 1.2 vs 21.8 +/- 4.5; p < 0.005), whereas in the budding neointima, the difference in the number of proliferating cells was not significant. Neointimal lesions 21 days after the injury did not differ in cross-sectional intimal area, in intimal/medial area ratio, and in cell density. CONCLUSION: Nitroglycerin decreased medial cellular proliferation after balloon injury and had no significant effect on intimal proliferation. The size of the neointimal lesion was not affected by nitroglycerin therapy.

Use of the air plethysmograph in the evaluation and treatment of patients with venous stasis disease.

BACKGROUND: Some patients with venous stasis disease require physiologic testing of venous function for complete evaluation prior to and/or after treatment. OBJECTIVE: To review basic uses of the air plethysmograph in evaluating patients with venous stasis disease. METHODS: The air plethysmograph can be used to quantitate obstruction, reflux, and the effectiveness of the calf muscle pump. RESULTS: Significant outflow obstruction is indicated by an outflow fraction of less than 35%. A venous filling index of 2 ml/second or greater indicates significant reflux. An ejection fraction of less than 40% is associated with poor calf muscle pump function. CONCLUSIONS: The air plethysmograph can be used in the evaluation of patients with venous stasis disease to quantify venous abnormalities of obstruction, reflux, and poor muscle calf pump function.

The etiology of intimal hyperplasia.

Injury of an arterial wall results in the growth of a neointima which can cause significant luminal narrowing. Current theories do not adequately explain the experimental and clinical data. We propose the hypothesis that some substance produced by the media is inhibitory to smooth muscle cell proliferation. This substance cannot cross the normal intima. Following an injury which removes the intima this substance quickly diffuses out of the arterial wall into the blood, its concentration in the arterial wall falls and proliferation of smooth muscle cells begins. Later, as the arterial wall volume increases and the lumen (and, thus, area for diffusion) decreases, the substance returns to inhibitory levels and intimal hyperplasia ceases.