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Biomedical subjects

R A Baum

Publications and source records attributed to R A Baum.

At least 55 records · Page 3Linked to original sources
PubMed1994

Evaluation of renal artery stenosis by magnetic resonance angiography.

BACKGROUND: Accurate identification of patients with surgically correctable renovascular hypertension has been difficult by noninvasive means. Advances in the technique of magnetic resonance angiography (MRA) have begun to provide detailed, accurate imaging of the vascular system. This study reports our recent experience in the evaluation of the renal arteries by this technique. METHODS: MRA and contrast arteriography were performed in 32 arteries (16 adult patients) for evaluation of hypertension, abdominal aortic aneurysm, mesenteric vascular disease, and aorto-iliac occlusive disease. Luminal diameter reduction (%) was determined from two-dimensional time-of-flight (TOF) axial images. Contrast arteriography served as the gold standard for comparison. RESULTS: Contrast arteriography revealed a 50% or greater stenosis in 11 of 32 vessels studied (34%). As a screening test for detection of greater than 50% diameter reduction, MRA had a sensitivity of 91%, a negative predictive value of 94%, and an overall accuracy of 81%. Linear regression analysis demonstrated significant correlation between MRA and arteriographic measurements (r = 0.8; P < 0.001). CONCLUSIONS: This study demonstrates the ability of MRA to accurately assess the main renal arteries for the presence of critical stenosis. This noninvasive evaluation compares well with conventional angiography and may have increasing application in the screening of patients with suspected renovascular disease.

Adult↗
PubMed1994

Intracardiac thrombosis and antiphospholipid antibodies: a case report and review of the literature.

A case report and review of the literature are reported concerning the relationship of intracardiac thrombosis and antiphospholipid antibody syndromes. Nine cases are identified, divided into three categories: three patients had antiphospholipid syndrome associated with systemic lupus erythematosus, three had primary antiphospholipid syndrome, and three had probable secondary antiphospholipid syndrome. All had intracardiac thrombosis. All patients were women, and the average age was 36 years. Although intracardiac thrombosis appears to be an unusual association with antiphospholipid antibody syndromes, young women with embolic events should be evaluated for antiphospholipid antibodies and intracardiac source of embolus.

Antibodies, Antiphospholipid↗
PubMed1994

Transjugular intrahepatic portosystemic shunt stenosis and revision: early and midterm results.

OBJECTIVE: The purpose of this study was to define the pattern, rate, and interval during which stenosis develops in transjugular intrahepatic portosystemic shunts (TIPS) and to assess the effect of revision in prolonging shunt patency. MATERIALS AND METHODS: TIPS were created in 100 patients during a 34-month period. Sixty-one shunt venograms were obtained in 38 consecutive patients between 1 and 24 months after TIPS placement. Eighteen patients were examined because of recurrent symptoms, and all 38 had routine follow-up. RESULTS: Stenoses attributed to neointimal hyperplasia developed within both the TIPS stent and the outflow hepatic veins. Stenoses of greater than 50% developed in 12 patients within 6 months of TIPS placement. In addition to focal stenoses, the outflow hepatic veins diffusely shrank an average of 51% in diameter. Thirty-six shunt interventions were required: eleven balloon dilatations and 25 placements of an additional stent. Life-table analysis showed that patency of the primary shunt was 75% at 6 months, 50% at 1 year, and 32% at 2 years. The primary-assisted patency of the shunt was 85% at 12 months after shunt creation. CONCLUSION: The results indicate that TIPS are prone to significant and frequent early stenosis, warranting follow-up within 3-6 months in all cases. Stenosis of the outflow hepatic vein is the most common cause of shunt malfunction. Revision of a shunt significantly prolongs shunt patency.

Catheterization↗
PubMed1994

Magnetic resonance angiography of the aorta, iliac, and femoral arteries.

BACKGROUND: Successful management of patients with peripheral vascular disease requires detailed vascular imaging, usually performed by contrast arteriography. Recently, magnetic resonance angiography (MRA) has been shown to be a noninvasive technique with greater sensitivity than contrast arteriography for detecting distal runoff vessels in patients with peripheral arterial occlusive disease. However, to supplant the need for contrast arteriography and provide a completely noninvasive evaluation of patients with occlusive disease, accurate imaging of the inflow vessels and the runoff vessels is necessary. METHODS: We used both conventional arteriography and MRA in preoperative studies of the aorta, iliac, and femoral vessels of 47 patients. Conventional arteriography and MRA studies were compared for their ability to detect vessel patency and the presence of hemodynamically significant stenoses. Independent interventional plans were developed based on the information provided by each technique. The findings of conventional and MRA studies were verified by intraoperative arteriography or direct operative exploration. RESULTS: Results of the two studies were identical in 41 (87%) of 47 patients or 600 (98%) of 614 segments imaged. MRA accurately detected patent and occluded arterial segments (sensitivity 99.6%, specificity 100%, positive predictive value 100%, negative predictive value 98.6%) and hemodynamically significant stenoses. Therapeutic plans based on either MRA or conventional arteriography were identical for each patient. CONCLUSIONS: MRA provides comparable results to contrast arteriography in the proximal arterial system and superior results for imaging the distal vasculature. This noninvasive technique may replace contrast arteriography in a large number of patients in the future.

Adult↗
PubMed1994

Magnetic resonance angiographic imaging of angioplasty and atherectomy sites.

UNLABELLED: Magnetic resonance angiography (MRA) provides detailed morphologic and flow information that demonstrates complex changes at sites of percutaneous transluminal angioplasty (PTA) and atherectomy. The purpose of this study is to examine the appearance of the vessel by MRA in the initial post-procedural and early follow-up periods. METHODS: MRA was performed to evaluate 35 infrainguinal endovascular procedures (20 patients), including PTA (20), atherectomy (4), and combination PTA/atherectomy (11). MRA imaging was performed within 24 hours of the procedure and at a mean follow-up interval of 3.5 months (range 1-8). RESULTS: Abnormalities in the immediate post-procedural MRA were seen in 55% of the PTA group and 93% of the atherectomy group (p = 0.04). Importantly, three of 35 lesions (9%) were shown by MRA to harbor > 50% stenoses despite angiographically "successful" procedures. Follow-up MRA showed abnormalities in 25% of those undergoing PTA, and in 67% of those with atherectomy (p = 0.01). At the time of follow-up MRA, four areas showed > 50% stenosis and four areas showed occlusion, revealing unfavorable outcomes in 22%. CONCLUSIONS: MRA provides a detailed noninvasive image of the sites of endovascular interventions and reveals vessel wall abnormalities not appreciated by conventional arteriography. Continued observation may allow prediction of segments at increased risk for restenosis.

Aged↗
PubMed1993

Comparison of magnetic resonance angiography and contrast arteriography in peripheral arterial stenosis.

Magnetic resonance angiography (MRA) has recently been shown to be more sensitive than contrast arteriography in the detection of patent distal runoff vessels. This study compares MRA and contrast arteriography in evaluating the severity of stenotic lesions in peripheral arteries, which has not been previously investigated. Forty-eight arterial stenoses (19 patients) were identified, from the distal aorta through the crural vessels. Contrast arteriograms (anterioposterior projection) and MRA axial images were used to measure stenoses. Interobserver agreement of arteriogram readings was excellent (average weighted k = 0.87). Measurements of degree of stenosis as evaluated by MRA and contrast arteriography were analyzed by linear regression and Spearman rank correlation, which showed a high degree of correlation between the two diagnostic modalities (r = 0.83, p < 0.001; rs = 0.84, p < 0.001). These observations suggest that MRA is accurate in the evaluation of peripheral arterial stenosis when compared with the "gold standard" contrast arteriogram. In addition, MRA cross-sectional images provide information beyond that of conventional arteriography, showing details of plaque eccentricity and vessel wall characteristics. In the future, MRA may supplant diagnostic contrast arteriography for many patients.

Adult↗
PubMed1993

Infrageniculate bypass graft entrapment.

When failure of vein grafts is due to technical error it is usually observed in the early postoperative period. In this review we describe late failure of five bypass grafts as a result of entrapment of the vein graft caused by an improperly placed tunnel from the femoral to the popliteal artery. Vein graft entrapment may either produce no symptoms or eventually lead to limb ischemia. Pulses and pressures that vary with flexion and extension maneuvers should alert the clinician to the possibility of an entrapment syndrome. The characteristic arteriographic findings observed in these patients include an aberrant course of the vein graft outside the anatomic course of the popliteal artery and position-dependent compression of the graft. The ability of magnetic resonance angiography to demonstrate the arteriographic appearance of the graft as well as the precise location of the compression and to identify structures involved in the entrapment, make it a valuable noninvasive tool in the preoperative assessment of these patients. Treatment options include division of the gastrocnemius muscle, division of the vein graft, or replacement of the vein graft. Familiarity with vein graft entrapment should facilitate its recognition. Careful placement of bypass grafts along the anatomic course of the popliteal artery within the popliteal space will prevent this complication.

Aged↗
PubMed1993

Magnetic resonance venography for the detection of deep venous thrombosis: comparison with contrast venography and duplex Doppler ultrasonography.

PURPOSE: Contrast venography is the gold standard for diagnosis in deep venous thrombosis (DVT); however, this technique is invasive and requires the use of potentially hazardous contrast agents. Although duplex Doppler ultrasonography is accurate in the evaluation of lower extremity DVT, it is less accurate in the assessment of the pelvic and intraabdominal veins. Magnetic resonance venography (MRV) has recently been developed, and our purpose was to determine whether MRV could accurately demonstrated DVT when compared with duplex scanning and contrast venography. METHODS: Eighty-five patients underwent contrast venography and MRV from the inferior vena cava to the popliteal veins to rule out DVT. Thirty-three of these patients also underwent duplex scanning. Blinded readings of these studies were compared for the presence or absence and extent of venous thrombosis. RESULTS: DVT was documented by contrast venography in 27 (27%) venous systems. Results of MRV and contrast venography were identical in 98 (97%) of 101 venous systems, whereas results of duplex scanning and contrast venography were identical in 40 (98%) of 41 venous systems. All DVTs identified by contrast venography were detected by MRV and duplex scanning. The discrepancies were due to false-positive MRV (3) and duplex scanning (1) results. When compared with contrast venography, MRV had a sensitivity of 100%, specificity of 96%, positive predictive value of 90%, and negative predictive value of 100%. For duplex scanning the sensitivity was 100%, specificity was 96%, positive predictive value was 94%, and negative predictive value was 100%. CONCLUSIONS: It is concluded that MRV is an accurate noninvasive venographic technique for the detection of DVT.

Humans↗
PubMed1993

Symptomatic peripheral vascular disease: selection of imaging parameters and clinical evaluation with MR angiography.

In the first phase of this study, seven healthy subjects underwent examination with two-dimensional time-of-flight (TOF) magnetic resonance (MR) angiography to develop a protocol for evaluation of peripheral arterial vasculature from the infrarenal aorta to the foot. In the second phase, 73 patients with symptomatic peripheral vascular disease underwent examination with both conventional contrast material-enhanced arteriography and two-dimensional TOF MR angiography to evaluate the clinical usefulness of MR angiography. Postinterventional and intraoperative angiography or direct surgical exploration was the standard of reference. In 32 patients, discrepancies occurred between findings on arteriograms and those on MR angiograms; most of these discrepancies were caused by improved depiction of runoff vessels on MR angiograms. The demonstration with MR angiography of blood vessels not seen on conventional arteriograms, unidentified stenoses, or misidentified blood vessels altered surgical management in 12 patients (16%). Metal-clip artifacts obscured clinically important disease on MR angiograms in two patients. It is concluded that two-dimensional TOF MR angiography is very useful in preoperative assessment of patients with severe peripheral vascular disease.

Adult↗
PubMed1993

Magnetic resonance arteriography of the pelvis and lower extremities.

Reconstructive vascular surgery is the last resort for limb salvage in patients with vascular insufficiency. Planning the sites of arterial bypass grafts depends on an exact knowledge of the angiographic anatomy. Currently, conventional contrast angiography is the primary preoperative study for surgical planning. Recently, magnetic resonance (MR) arteriography has been shown to be an accurate technique for the evaluation of slow arterial flow in the lower extremities. The purpose of this review will be to show how MR arteriography can be used as both an adjunct to and in some cases instead of conventional angiography for the preoperative assessment of lower-extremity vascular reconstruction. The derivation of common artifacts, the many pitfalls of interpretation, and the evaluation of peripheral arterial occlusion and percentage stenosis will be discussed. MR arteriography of the lower extremities is an important advance for the noninvasive evaluation of disease of the peripheral vasculature.

Algorithms↗
PubMed1992

Magnetic resonance imaging of angiographically occult runoff vessels in peripheral arterial occlusive disease.

BACKGROUND: Bypass grafting to arteries of the lower leg has become standard surgical management of advanced peripheral vascular disease. Its success depends on identifying suitable distal vessels. Preoperative preparation includes imaging of the arteries of the lower leg, usually by conventional contrast arteriography. An alternative procedure, magnetic resonance (MR) angiography, has been successfully employed in patients with various cardiovascular diseases, but its possible value in patients with peripheral vascular disease has received little attention. METHODS: We used both conventional and MR angiography in preoperative studies of the lower-leg vessels of 23 patients (25 legs) with peripheral arteriosclerosis and arterial insufficiency, and developed independent therapeutic plans based on the information provided by each technique. When the plans differed, the interventional procedure judged more likely to save the limb was performed. The findings of conventional and MR angiography were verified by intraoperative arteriography, postinterventional arteriography, or direct operative exploration. RESULTS: MR angiography detected all vessels identified by conventional angiography, whereas conventional arteriography failed to detect 22 percent of the runoff vessels identified by MR angiography. The detection by MR angiography of vessels not identified by conventional angiography altered the surgical management of the disorders of four patients (17 percent) and guided successful bypass procedures. CONCLUSIONS: MR angiography is a noninvasive technique with greater sensitivity than conventional contrast arteriography for detecting distal runoff vessels in patients with peripheral arterial occlusive disease.

Aged↗
PubMed1992

Magnetic resonance angiography of peripheral runoff vessels.

Recent improvements in magnetic resonance imaging techniques have made magnetic resonance angiography (MRA) a very useful adjunct to invasive angiography. Fifty-five limbs in 51 patients with occlusive peripheral vascular disease were studied with both MRA and contrast arteriography. The magnetic resonance and contrast arteriograms were read by radiologists and surgeons and separate interventional plans were based on each study. The MRA findings differed significantly from those of conventional arteriography in 26 limbs (48%). In every case MRA visualized all of the same vessels and hemodynamic stenoses seen on the contrast arteriogram. In 48% of the cases, however, MRA revealed additional findings. Thus the discrepancies in the two studies were always the result of the failure of the arteriogram to reveal all of the patent vessels seen on MRA. The additional information provided by MRA resulted in alteration of the interventional plan in 11 cases (22%). In nine cases (18%) target vessels suitable for use in a limb-salvage procedure were identified by MRA, although they had been missed by conventional arteriography. In all of these cases, intraoperative arteriograms confirmed the suitability of these vessels for use in technically successful bypass procedures. In two cases (4%) additional information provided by MRA identified a target runoff vessel for bypass grafting that proved to be a better alternative than the one that would have been chosen on the basis of contrast arteriography.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Peritoneovenous shunting as compared with medical treatment in patients with alcoholic cirrhosis and massive ascites. Veterans Administration Cooperative Study on Treatment of Alcoholic Cirrhosis with Ascites.

The optimal management of severe ascites in patients with alcoholic cirrhosis has not been defined. in a 5 1/2-year study, we randomly assigned 299 men with alcoholic cirrhosis, who had persistent or recurrent severe ascites despite a standard medical regimen, to receive either intensive medical treatment or peritoneovenous (LeVeen) shunting. We identified three risk groups: Group 1 had normal or mildly abnormal results on liver-function tests, Group 2 had more severe liver dysfunction or previous complications, and Group 3 had severe prerenal azotemia without kidney disease. For the patients who received the medical treatment and those who received the surgical treatment combined, the median survival times were 1093 days in Group 1, 222 days in Group 2, and 37 days in Group 3 (P less than or equal to 0.01) for all comparisons). For all the groups combined, the median time to the resolution of ascites was 5.4 weeks for medical patients and 3.0 weeks for surgical patients (P less than 0.01). Within each risk group, mortality during the initial hospitalization and median long-term survival were similar among patients receiving either treatment. However, the median time to the recurrence of ascites in Group 1 was 4 months in medical patients, as compared with 18 months in surgical patients (P = 0.01); in Group 2 it was 3 months in medical patients as compared with 12 months in surgical patients (P = 0.04). The median duration of hospitalization was longer in medical patients than in surgical patients (6.1 vs. 2.4 weeks in Group 1 [P less than 0.001] and 5.0 vs. 3.1 weeks in Group 2 [P less than 0.01]). Group 3 was too small to permit a meaningful comparison. During the initial hospitalization, the incidence of infections, gastrointestinal bleeding, and encephalopathy was similar among the medical and surgical patients. We conclude that peritoneovenous shunting alleviated disabling ascites more rapidly than medical management. However, survival was closely related to the severity of the illness at the time of randomization and was not altered by shunting.

Ascites↗
PubMed1987

Relationship between self-actualization and self-reported health practices.

To compare the reported health practices of high self-actualizing individuals with those of low self-actualizing individuals, 453 students enrolled in personal hygiene classes at a large southern university completed the Personal Orientation Inventory, a measure of self-actualization. The fifty highest scorers were identified as the high self-actualizing group and the 50 lowest scorers were identified as the low self-actualizing group. The two groups were administered the Health Practices Inventory. The high self-actualizing group reported using better health practices.

Adult↗
PubMed1984

Low-dose chenodiol to prevent gallstone recurrence after dissolution therapy.

Chenodiol is a safe and effective agent for the medical dissolution of gallstones in selected patients; however, after dissolution and cessation of treatment, gallstones recur. This study was done to determine the recurrence rate after successful medical treatment and cessation of chenodiol therapy; compare the efficacy and safety of low-dose chenodiol, as compared to placebo, for prophylaxis against recurrence; and identify factors predictive of recurrence. In a randomized, double-blind fashion, 53 patients with gallstone dissolution received either chenodiol, 375 mg/d, or placebo, for at least 2 years. Standardized oral cholecystograms were done at 6 months, 1 year, and then yearly thereafter. Routine laboratory testing was done every 6 months. The cumulative rate of recurrence (life-table) was 27% in patients followed for up to 3.5 years. Chenodiol, 375 mg/d, was ineffective in preventing the recurrence of gallstones. No demographic, clinical, roentgenographic, or biochemical characteristics were predictive of recurrence.

Aged↗