Biomedical subjects

A D Callow

Publications and source records attributed to A D Callow.

At least 91 records · Page 5Linked to original sources

PubMed1980

Diagnosis of deep venous thrombosis in the outpatient by venography.

One hundred and two patients, presenting at the outpatient departments of two Boston teaching hospitals, underwent clinical examination and venography. History, physical examination and presence of risk factors were unreliable in the diagnosis of deep venous thrombosis. Seventy-two per cent of the patients with deep venous thrombosis had a proximal extension of the thrombus to the femoral vein or higher. The outpatient with deep venous thrombosis appears to differ from the more frequently studied inpatient in the time of diagnosis and its anatomic extent. The high incidence of false-positive clinical examination results has important cost-benefit implications.

Adult↗

PubMed1980

The economic impact of acute variceal bleeding: cost-effectiveness implications for medical and surgical therapy.

The hospital costs and its respective components for 32 patients with acute variceal bleeding were determined. The average total cost for treating the 32 patients was $35,000. The cost for those patients who underwent elective surgery ($53,000) was approximately twofold that of the elective medical group. Nutritional and metabolic rehabilitation that prolonged hospitalization, reutilization of the intensive care unit, and perioperative blood requirements were the significant factors that increased the cost of treating the surgically treated patients. Derivation of the cost/benefit ratio, however, showed that the decreased rehospitalization rate of the surgically treated group and the apparent better "quality of life" almost offset the increased initial hospital costs for this group.

Adult↗

PubMed1980

The relative value of carotid noninvasive testing as determined by receiver operator characteristic curves.

To determine the relative value of carotid phonoangiography (CPA), oculoplethysmography-Kartchner (OPG-K), and Doppler ultrasonic arteriography (UA), 90 vessels undergoing carotid endarterectomy were prospectively examined. By analyzing the data on receiver operator characteristic curves, the dynamic relationship between sensitivity and specificity for each of the three noninvasive tests was assessed. Disease was defined by either the percentage of angiographic stenosis or the mean pressure gradient across the carotid (deltaP). All three tests were shown to be relatively insensitive, but quite specific, if disease was defined by 50% and 60% angiographic stenosis or deltaP of greater than 10 and 20 mm Hg. By employing a more rigid definition of disease, 70% stenosis or deltaP of greater than 30 mm Hg, sensitivity was increased for all examinations and was highest in OPG-K and UA for a given specificity. The sensitivity for UA was enhanced to 80% with a comparable specificity, if those 23 UA exams with plaque were treated as positive studies. The combination of CPA, OPG-K, and UA was superior to any one of these tests alone, but the best value balancing maximum sensitivity and specificity still was associated with a 23% false negative rate. This study would suggest that these three tests should be limited to screening patients at risk for carotid stenosis and not for symptomatic patients. To achieve the best balance between sensitivity and specificity, lax threshold criteria for calling the test positive should be employed, and the tests should be used in combination.

Angiography↗

PubMed1980

A comparison of the early noninvasive hemodynamic results after aortofemoral or axillofemoral bypass graft.

Aortofemoral (AF) and axillofemoral bypass grafts (AXFG) are alleged to have similar patency rates, but little is known of their comparative functional results. In 91 limbs clinically selected for AXFG or AF, pulse volume recording amplitude (PVR) and Dopper systolic ankle/brachial artery pressure ratio (DSP A/B) were measured before and 6 months after surgery. Preoperatively, the limbs were classified by angiography into aortoiliac disease alone (AI) or AI and femoropopliteal disease (AIFP), and were further classified by PVR and DSP A/B into claudication and limb salvage groups. Six months after surgery, the degree of hemodynamic improvement was comparable for AF and AXFG for limbs with AI. After AXFG in AIFP, however, the claudication group showed less of an improvement in DSP A/B ratio and PVR than with AF. There was no functional improvement after AXFG in the limb salvage group. AF appears to be associated with better functional results than AXFG in AIFP.

Arterial Occlusive Diseases↗

PubMed1979

Effect of elastic compression on venous hemodynamics in postphlebitic limbs.

To determine whether elastic compression alters the venous hemodynamics in the postphlebitic limb, we measured venous pressure patterns in 11 postphlebitic limbs with and without elastic compression stockings. Following cannulation of a dorsal vein of the foot, the patients underwent measurements of basal resting pressure, maximum percent decrease in venous pressure with exercise (delta VPex), peak systolic venous pressure during exercise (SVPmax), the amplitude of the pressure swing, and venous return time. Elastic compression did not alter basal resting pressure, delta VPex, or venous return time. By contrast, SVPmax decreased from 139 +/- 0.3 mm Hg to 11 +/- 8 mm Hg with elastic compression. If venous ulcers are related to the high pressure developed in the superficial veins during calf muscle systole, then elastic compression may be beneficial by decreasing systolic venous pressure and its subsequent deleterious consequences.

Bandages↗

PubMed1979

Prophylactic interruption of the inferior vena cava: immediate and long-term hemodynamic effects.

Two hundred patients were evaluated retrospectively to determine the clinical effects of prophylactic inferior vena cava (IVC) interruption in association with aortic reconstruction. No pulmonary embolism occurred in the group with IVC interruption, but embolisms did occur in seven of 68 patients who had aortic reconstruction performed without IVC interruption. In two patients, the pulmonary embolism was fatal. Postoperative incidence of deep vein thrombosis was fatal. Postoperative incidence of deep vein thrombosis was 9% in both groups. Clinical and hemodynamic effects of prophylactic IVC interruption were studied in 20 additional patients. Venous hemodynamics (maximum venous outflow, inferior vena cava pressure, and ambulatory venous pressure) showed no change following interruption in 19/20. Sixteen patients from the original group of patients with prophylactic interruption were studied hemodyamically. No pulmonary embolism was clinically evident. One new case of deep vein thrombosis was seen. Again, venous hemodynamics showed no change as a result of IVC interruption. Prophylactic IVC interruption is a safe means of decreasing the incidence of pulmonary embolism without increasing venous-related morbidity.

Aorta↗

PubMed1979

Positive blood culture as an aid in the diagnosis of secondary aortoenteric fistula.

The successful management of aortoenteric fistula (AEF) requires early diagnosis. To evaluate the accuracy of our diagnostic approach, the hospital course of seven patients with AEF was reviewed. In six patients, the initial bleeding episodes were of the low volume type characterized by hematemesis and melena or by melena alone. All patients were febrile. In six patients, blood cultures obtained preoperatively were positive for enteric organisms identical to those found in cultures obtained intraoperatively from the AEF site. Roentgenographic examination of the upper gastrointestinal (GI) tract performed in three patients was diagnostic for AEF in only one. Endoscopy in seven patients revealed a bleeding suture line in one. Angiography was not diagnostic in the six patients in whom it was performed. When patients are seen with the triad of GI bleeding, a history of aortic surgery, and fever, aerobic and anaerobic blood cultures should be obtained. If blood cultures are positive for enteric organisms, the diagnosis of AEF should be strongly suspected, and early surgical intervention is indicated.

Aged↗

PubMed1979

Failure of carotid stump pressures. Its incidence as a predictor for a temporary shunt during carotid endarterectomy.

A total of 289 carotid endarterectomies were performed in 204 patients. A decision to place a temporary shunt during carotid endarterectomy in this series was made entirely on the basis of intraoperative EEG monitoring. Retrospectively, the correlation between stump pressures and the results of intraoperative EEG monitoring in each case was determined. Evidence of ischemia developed in 6% of the total series on intraoperative EEG monitoring despite a stump pressure of greater than 50 mm Hg. The degree of disagreement between stump pressure and EEG varied according to clinical category in this series. In those endarterectomies performed for completed stroke, all cases requiring shunting had stump pressures less than 50 mm Hg. In those cases performed for symptoms of vertebral basilar insufficiency, however, 77% of the cases requiring an intraoperative shunt had stump pressures greater than 50 mm Hg. A review of the complication rate in the various study groups indicates that the use of intraoperative EEG is a safe indicator of cerebral ischemia during carotid endarterectomy regardless of stump pressure.

Blood Pressure↗

PubMed1979

Prophylactic interruption of the inferior vena cava. A retrospective evaluation.

One hundred sixty patients were retrospectively evaluated to determine the effect of prophylactic inferior vena caval interruption in association with aortic surgery. Sixty-three patients underwent aortic procedures without inferior vena caval interruption and ninety-seven patients underwent placement of an Adams-DeWeese clip as prophylaxis against pulmonary embolism. Pulmonary embolism occurred in 10 per cent of the group without the clip and in no patients in the group with the clip. The incidence of deep vein thrombosis was identical in both groups (10 per cent). The 6 per cent rate of early (within 6 months) postoperative leg edema in the group with the inferior vena caval clip was a significant problem in only one patient after twenty-four months. Prophylactic interruption of the inferior vena cava has been shown to be a safe method of decreasing the incidence of pulmonary embolism without increasing the incidence of venous-related complications.

Aged↗

PubMed1979

Interposition grafting with expanded polytetrafluoroethylene for portal hypertension.

If an interposition graft for the decompression of esophageal varices is necessary, Gore-Tex may be the graft material of choice. It is intert, nonthrombogenic and, possibly, thrombo-resistant. These characteristics of Gore-Tex explain the ease with which a graft thrombectomy was performed in one patient when necessary. Final appraisal of a synthetic venous prosthesis requires many months, if not years, of in vivo evaluation. Nevertheless, when an interposition graft is necessary for the decompression of esophageal varices, it appears that a clinical trial of Gore-Tex is reasonable in view of its characteristics.

Adult↗

PubMed1979

A prospective study of Doppler pressures and segmental plethysmography before and following aortofemoral bypass. Implications for predicting success and for adopting a uniform method of classifying arterial disease.

To determine the clinical and hemodynamic changes associated with aortofemoral bypass, 44 limbs of 31 patients underwent segmental plethysmography (PVR) and Doppler pressures (DSP) before operation, immediately after operation, and again at 6 months. Prior to operation patients were separated by angiographic criteria into two groups: aortoiliac segment disease alone (AI) (n = 22), and aortoiliac and femoropopliteal segment disease (AIFP) (n = 22). At 6 months the two groups were subdivided into four groups based on relief (oSx) or lack of relief (+Sx) of symptoms. Before operation the only significant difference between the four groups was a higher thigh PVR and calf DSP in the AI + Sx group. Six month PVR values in AIoSx were improved nearly twofold over preoperative measurements at the thigh and calf, but at the thigh level only for AIFPxSx. DSP was increased at all three levels in both AI and AIFPoSx groups. No hemodynamic improvement occurred in either the AI or the AIFP + Sx groups. A derivative index of PVR (thigh-ankle/15 mm) or the FPomega was significantly lower in AIFOsSx before operation. There was a significant disparity between classification by hemodynamics and by symptoms prior to operation which lessened somewhat after operation. These studies suggest that success or failure can be predicted before operation in AIFP by FPomega, and arterial disease should be classified by a combination of symptoms, angiography, and hemodynamics.

Angiography↗

PubMed1979

Chronic mesenteric ischemia masquerading as cancer.

Mesenteric vascular insufficiency should be suspected in patients with a history of abdominal pain, marked weight loss and significant atherosclerosis. Selective mesenteric angiography is essential and should be used early in the work-up studies of such patients. To ensure clinical correlation, there should be significant occlusion demonstrated in two of the three major mesenteric arteries. Four patients studied extensively for an intra-abdominal neoplasm had occlusive disease of the mesenteric artery demonstrated by arteriography. Elective surgical revascularization of the intestine successfully corrected the problem.

Abdominal Neoplasms↗

PubMed1978

Early restenosis after carotid endarterectomy.

Restenosis within 24 months of carotid endarterectomy was discovered in 3.6% of 361 operations. The patients in this group of restenosis tended to be younger than the overall group. Hypertension and hyperlipidemia were also more frequent. Restenosis recurred within an average of 12.5 months of the first operation, with a range from five to 24 months. No surgical technical causes could be found. Restenosis is attributed to rapid, exuberant myointimal proliferation. This process is histologically distinct from the atherosclerotic plaque which is the cause of late restenosis. Reoperation on this group of patients with the fibrous myointimal proliferative type of lesion was difficult and was infrequently associated with improvement in the patients' signs and symptoms.

Aged↗

PubMed1978

The Grimonster symposium on the occasion of the 50th anniversary of the first lumbar sympathectomy.

Under the auspices of the Belgian Surgical Society, a small group of American and European surgeons discussed in detail the place of lumbar sympathectomy in present day surgical practice. A consensus was reached concerning the physiologic effect, anatomical variations and indications for the operation. Conclusions included the questionable value of lumbar sympathectomy for treating intermittent claudication due to aortoiliac disease alone, its possible effectiveness when obliterative arterial disease is limited to the femoral popliteal segment, and its occasional beneficial effect when performed in conjunction with some reconstructive arterial operations.

Belgium↗

PubMed1978

Results of carotid endarterectomy for vertebrobasilar insufficiency: an evaluation over ten years.

A review was performed of 114 patients with symptoms of vertebrobasilar insufficiency (VBI) alone, or in combination with carotid territory transient ischemic attacks or carotid territory completed stroke (cCS) with follow-up extending to ten years. The most frequent symptoms of VBI were visual changes (50%), dizziness (31%), and syncope (30%). Patients with symptoms of VBI and arteriographic evidence of intracranial disease, regardless of stump pressure, are at high risk for cerebral ischemia during endarterectomy. At late follow-up, ranging from one to ten years, 63% of the patients were alive; 88% were asymptomatic. Causes of death were mainly cardiac (44%) and stroke (36%), but patients with symptoms of VBI and cCS died earlier and from a second cerebrovascular accident. When a correct preoperative diagnosis was established, carotid endarterectomy produced relief of symptoms in 90% of the patients.

Adult↗

PubMed1978

Noninvasive intraoperative monitoring: a prospective study comparing Doppler systolic occlusion pressure and segmental plethysmography.

Seventy-two limbs in forty patients underwent Doppler systolic ankle pressure and Pulse Volume Recording (PVR) amplitude measurements intraoperatively. Control patients and patients undergoing abdominal aortic aneurysm (AAA) resections showed no significant decrease in Doppler systolic ankle/brachial pressure ratio (DSAB). PVR measurements were slightly decreased after declamping in the AAA patients. Femoropopliteal bypass was associated with a prompt increase in PVR and DSAB levels. In contrast, postreconstruction values in the extraanatomic (EA) and aortofemoral (AF) bypass groups were dependent upon the patency of the femoropopliteal segment. Intraoperative monitoring provides a quantitative assessment of the immediate success of arterial surgery.

Ankle↗

PubMed1977

Hazards and safeguards during carotid endarterectomy. Technical considerations.

The hazards and safeguards of carotid endarterectomy are presented in a consecutive series of 130 patients over a fourteen month period. The mortality rate of 1.5 per cent was due to myocardial infarction. Two patients (1.5 per cent) suffered minor but permanent neurologic deficit. There was an incidence of 4.6 per cent transient neurologic deficits, all of which cleared within 24 hours. Special emphasis is placed on peripheral nerve injuries (12.3 per cent). Local neurologic anatomy is reviewed to facilitate safe dissection and an avoidance of nerve injury.

Carotid Artery Diseases↗

PubMed1977

Survival in patients with postnecrotic cirrhosis and Laennec's cirrhosis undergoing therapeutic portacaval shunt.

Survival rates were compared in 82 patients who underwent therapeutic portacaval shunt. All patients were followed for at least 5 years after shunt or until death. Survival rates were calculated by Life Table methods. Based on a combination of currently accepted histological and clinical criteria, there were 45 patients with Laennec's cirrhosis, 29 patients with postnecrotic cirrhosis, 11 of whom had histological evidence of chronic active hepatitis, and 8 patients with primary biliary cirrhosis. Survival rates were similar in all three groups, alcoholic cirrhosis, postnecrotic cirrhosis, and primary biliary cirrhosis. Hepatic reserve, as defined by Child's classification, provided the best criteria for predicting survival. The type of shunt, end-to-side, side-to-side, or splenorenal, did not influence survival. Histological evidence of chronic active hepatitis adversely affected survival in patients with postnecrotic cirrhosis. However, histological evidence of ongoing alcoholic hepatitis in patients with Laennec's cirrhosis did not influence survival adversely. The data indicate that once a patient with cirrhosis has bled from esophageal varices, the etiology of the cirrhosis is not a major factor in determining survival after a therapeutic portacaval shunt.

Adult↗