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Biomedical subjects

H B Wheeler

Publications and source records attributed to H B Wheeler.

At least 19 recordsLinked to original sources
PubMed1992

Physician practices in the management of venous thromboembolism: a community-wide survey.

Although there is a broad consensus on the optimum approach to the management of venous thromboembolism, there are few data from which to assess the extent of compliance with these recommendations. A community-wide study was therefore conducted in 16 short-stay hospitals in central Massachusetts to assess the clinical management of venous thromboembolism. Based on validated discharge diagnostic codes, there were 1231 clinically recognized cases of venous thromboembolism, 0.8% of 148,730 discharges in the 18-month period from July 1, 1988, to December 31, 1989. Eighty-one percent of study patients were admitted with signs or symptoms of acute venous thromboembolism. Ninety-seven percent of patients were treated with either heparin, warfarin, or inferior vena caval filter. Intravenous heparin was given to 89% of patients (mean bolus 6674 IU; mean duration 6.6 days). After heparin administration, there was a mean delay of 2.3 days in starting warfarin. Assuming a corresponding decrease in the length of hospital stay, appreciable cost savings could have been realized by earlier start of oral anticoagulation. An inferior vena cava filter was placed in 14% of patients. There was a clinically recognized in-hospital recurrence of venous thromboembolism during treatment in 2% of patients. Despite a slightly lower rate of compliance with recommended treatment regimens in nonteaching hospitals, and despite less frequent use of the inferior vena cava filter, there was no significant difference in the rate of in-hospital recurrence of clinically recognized venous thromboembolism in 10 nonteaching hospitals compared with six teaching hospitals.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

The prevalence of risk factors for venous thromboembolism among hospital patients.

BACKGROUND: This study provides an estimate of the prevalence of risk factors for venous thromboembolism among hospital patients. METHODS: The presence of risk factors for venous thromboembolism was determined from a retrospective review of the medical records of 1,000 randomly selected patients in 16 acute care hospitals in central Massachusetts. RESULTS: The most common risk factors for venous thromboembolism were age 40 years (59%) or more, obesity (28%), and major surgery (23%). The average number of risk factors increased with increasing age. One or more risk factors for venous thromboembolism were present in 78% of hospital patients, two or more in 48%, three or more in 19%, four or more in 6%, and five or more in 1%. CONCLUSION: Risk factors for venous thromboembolism are common among hospital patients, suggesting that prophylaxis should be widely employed. The cost-effectiveness and risk benefit of prophylaxis is well established in patients undergoing major surgery. Further studies are needed to confirm the benefit of prophylaxis in patients with nonsurgical risk factors for venous thromboembolism.

Age Factors↗
PubMed1992

Precoating expanded polytetrafluoroethylene grafts alters production of endothelial cell-derived thrombomodulators.

Although the use of extracellular matrix proteins to precoat small-caliber vascular grafts before endothelial cell seeding has been shown to improve cell attachment, proliferation, and adherence, the effect of precoating on the thrombomodulatory properties of the seeded cells is unknown. The use of vascular prostheses lined with confluent endothelial cell monolayers expressing optimal thromboresistant properties may enhance patency rates. In this study human saphenous vein endothelial cells were seeded onto expanded polytetrafluoroethylene (ePTFE) graft material, both unmodified and precoated with fibronectin, type I collagen, or fibronectin and type I collagen (fibronectin/type I collagen). After 3 days of in vitro cultivation, endothelial cell production of prostacyclin, tissue plasminogen activator, and plasminogen activator inhibitor was evaluated under basal conditions and after stimulation with arachidonate or thrombin. Production of tissue plasminogen activator by endothelial cells cultured on fibronectin-ePTFE was significantly greater compared with production by endothelial cells grown on noncoated or fibronectin/type I collagen-ePTFE under basal conditions (p values less than 0.01 and less than 0.05, respectively) and in response to thrombin (p values less than 0.002 and less than 0.003, respectively). Plasminogen activator inhibitor-1 production was not detected in any of the four experimental groups. Endothelial cells cultured on fibronectin-ePTFE also synthesized significantly more prostacyclin than endothelial cells grown on type I collagen- or fibronectin/type I collagen-ePTFE, under basal conditions (p values less than 0.02 and less than 0.01, respectively) and in response to arachidonate (p values less than 0.03 and less than 0.002, respectively) and thrombin (p values less than 0.003 and less than 0.002, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Vessel Prosthesis↗
PubMed1991

Physician practices in the prevention of venous thromboembolism.

OBJECTIVE: To determine the rate of use of prophylaxis for venous thromboembolism in high-risk hospital patients. DESIGN: A retrospective medical record review. SETTING: A community-wide study in 16 short-stay hospitals in central Massachusetts. PATIENTS: A total of 2017 patients with multiple risk factors for venous thromboembolism. MEASUREMENTS AND MAIN RESULTS: On the basis of age, length of hospitalization, and the presence of at least one additional major risk factor, 17% of 151,349 discharges (25,410 patients) were identified as being at high risk for venous thromboembolism. Eight percent of these discharges were randomly selected for medical record review. Prophylaxis for venous thromboembolism was received by 32% of these high-risk patients. Prophylaxis use among the 16 study hospitals varied widely, ranging from 9% to 56%, and was higher in teaching hospitals than in nonteaching hospitals (44% compared with 19%; P less than 0.001). One or more of the following methods of prophylaxis was used: low-dose heparin (78%), intermittent calf compression (13%), warfarin (12%), and inferior vena caval filter (3%). Use of prophylaxis increased with the number of risk factors identified (P less than 0.001). CONCLUSION: Prophylaxis for venous thromboemobolism is underused, particularly in nonteaching hospitals.

Adult↗
PubMed1991

Prophylaxis against venous thromboembolism in surgical patients.

Venous thromboembolic disease is a common, potentially life-threatening, but preventable complication of surgery. Venographic studies have shown a high incidence of deep vein thrombosis in patients who do not receive prophylaxis. The long-term sequelae of deep vein thrombosis in these patients can be disabling, but the exact prevalence of post-thrombotic complications has not been well documented. Fatal pulmonary embolism has been reported in 0.5% to 1% of patients after major abdominal surgery and in 2% to 6% after total hip replacement. Several methods of prophylaxis against venous thromboembolism have demonstrated efficacy, but a surprising number of patients still do not receive prophylaxis. A medical record review in 16 hospitals recently disclosed that only 32% of high-risk patients received prophylaxis, with a range from 9% in a community hospital to 56% in a major teaching hospital. The possible reasons for this comparatively low rate of utilization are discussed. Current issues and future trends in the prophylaxis of venous thromboembolism are briefly summarized.

Humans↗
PubMed1991

A population-based perspective of the hospital incidence and case-fatality rates of deep vein thrombosis and pulmonary embolism. The Worcester DVT Study.

A community-wide study was conducted in 16 short-stay hospitals in metropolitan Worcester, Mass, to examine the incidence and case-fatality rates of deep vein thrombosis and pulmonary embolism in patients hospitalized between July 1, 1985, and December 31, 1986. The average annual incidence of deep vein thrombosis alone was 48 per 100,000, while the incidence of pulmonary embolism with or without deep vein thrombosis was 23 per 100,000. The incidence rates of deep vein thrombosis and pulmonary embolism increased exponentially with age. The in-hospital case-fatality rate of venous thromboembolism was 12%. Among patients discharged from the hospital, the long-term case-fatality rates were 19%, 25%, and 30% at 1, 2, and 3 years after hospital discharge. Extrapolation of the data from this population-based study suggests that there are approximately 170,000 new cases of clinically recognized venous thromboembolism in patients treated in short-stay hospitals in the United States each year, and 99,000 hospitalizations for recurrent disease. Because of the silent nature of this disease and the low rate of autopsy in the United States, the total incidence, prevalence, and mortality rates of venous thromboembolism remain elusive.

Adolescent↗
PubMed1990

Randomized controlled trial of tissue plasminogen activator in proximal deep venous thrombosis.

PURPOSE: To compare the efficacy and safety of recombinant human tissue-type plasminogen activator (rt-PA, supplied as Activase) with heparin alone or rt-PA plus heparin in the treatment of venographically documented proximal deep venous thrombosis (DVT) of the leg. PATIENTS AND METHODS: Sixty-four patients underwent 65 randomizations to rt-PA alone (n = 36), rt-PA plus heparin (n = 17), or heparin alone (n = 12) in a prospective, multicenter, randomized, open-label trial, with efficacy assessed by a radiology panel unaware of treatment assignment. Patients randomly assigned to rt-PA received 0.05 mg/kg/hour for 24 hours via a peripheral vein, with a maximum dose of 150 mg. All patients then received heparin and warfarin for the remainder of the hospitalization. Follow-up venography was performed 24 to 36 hours after initiation of therapy. RESULTS: Complete or more than 50% lysis occurred in 10 (28%) patients treated with rt-PA, five (29%) patients with rt-PA plus heparin, and no patient treated with heparin. No lysis occurred in 16 (44%) patients treated with rt-PA plus heparin, and 10 (83%) patients who received heparin alone (p = 0.04). There was one major complication, a nonfatal intracranial hemorrhage in a patient who received rt-PA alone. At 7 to 10 days after initiation of treatment, the level of serum glutamic oxaloacetic transaminase nearly doubled among all patients, including those assigned to receive heparin alone. CONCLUSION: (1) rt-PA and rt-PA plus heparin cause more clot lysis than heparin alone; (2) the addition of heparin to rt-PA does not improve the lysis rate; (3) DVT treated with heparin is commonly associated with a rise in the transaminase level; (4) heparin does not increase the risk of bleeding from rt-PA therapy; and (5) alternative dosing regimens and modes of administration of rt-PA should be investigated to improve further its efficacy and safety in the treatment of acute DVT.

Adolescent↗
PubMed1990

Axillary artery compression and thrombosis in throwing athletes.

A 28-year-old major league baseball pitcher sustained an axillary artery thrombosis which was successfully treated with intraarterial urokinase. Subsequent angiography and duplex scanning with the arm elevated in the pitching position demonstrated inducible compression of the axillary artery by the humeral head as well as compression at the thoracic outlet. To determine the incidence of axillary and subclavian artery compression and to investigate the mechanism of injury, brachial artery blood pressures and duplex scans of the subclavian and axillary arteries were performed in both the neutral position and the throwing position in the 92 extremities of 19 major league baseball pitchers, 16 non-pitching major league players, and 11 nonathlete controls. A drop in blood pressure of greater than 20 mm Hg was noted in the position in 56% of extremities tested, with a loss of a detectable blood pressure in 13%. Compression of the axillary artery by the humeral head was documented in 83% of extremities, but in only 7.6% was a greater than 50% stenosis inducible. No statistical difference was found in the incidence of arterial compression between the three groups tested or between their dominant and nondominant extremities. Dissection of the axillary artery in two cadavers documented that abduction and external rotation of the arm causes compression of the axillary artery by the humeral head, which acts as a fulcrum. We conclude that the repetitive mechanical trauma of the throwing motion can cause intermittent compression and contusion of the axillary artery by the humeral head and predisposes the athlete who throws to thrombosis of the axillary artery.

Adult↗
PubMed1989

Extended indications for placement of an inferior vena cava filter.

To study the morbidity and mortality rates after placement of an inferior vena cava filter and to define the appropriate indications for interruption of the inferior vena cava, the records of all patients who underwent insertion of a Greenfield filter during the decade January 1978 to December 1987 were reviewed. Patients were designated as having either a traditional or extended indication for placement of an inferior vena cava filter. Two hundred sixty inferior vena cava filters were placed in 264 attempts, with no deaths related to insertion of the filter. An extended indication was the primary reason for placement of the Greenfield filter in 66 (25%) of the patients. In patients with extended indications there were no cases of air embolism or filter misplacement and only three wound complications (4.5%). Pulmonary embolism after insertion of the inferior vena cava filter occurred in three patients (4.5%), with one fatality (1.5%). Inferior vena cava occlusion was documented in three cases (4.5%), and manifestations of the postphlebitic syndrome in early follow-up were present in two patients (3.0%). As the procedures to prevent fatal pulmonary embolism have become safer, more efficacious, and less morbid, the number of patients in whom the potential benefits of insertion of an inferior vena cava filter outweigh the risks has become larger. Our results support the liberalized use of Greenfield filters in those patients who do not necessarily have one of the traditional indications for placement of an inferior vena cava filter but are at a high risk of having a fatal pulmonary embolus.

Anticoagulants↗
PubMed1988

Long-term survival and quality of life following ruptured abdominal aortic aneurysm.

To document both the long-term survival and the quality of life of patients following surgery for ruptured abdominal aortic aneurysm (AAA), the records of 65 patients with ruptured AAA resection were compared with those of 100 who underwent elective AAA resection. The actuarial survival following ruptured aneurysm surgery was 92%, 51%, and 51% at 1, 5, and 10 years, respectively, and did not differ statistically for patients after elective AAA surgery or for an age- and sex-matched sample from the general population. Based on responses to a quality of life survey, there were no discernible differences in life-style, degree of independence, or productivity following either ruptured or elective AAA surgery. Survivors of ruptured AAA have an excellent long-term prognosis and expectation for a good quality of life.

Age Factors↗
PubMed1987

The clinical implications of bilaterally abnormal impedance plethysmography.

Although impedance plethysmography (IPG) is a test of recognized value in the diagnosis of acute proximal deep venous thrombosis (DVT), its meaning in patients with bilaterally abnormal IPGs is unclear. Consequently, we sought to determine the clinical significance of the bilaterally abnormal IPG in hospitalized patients. In a five-month prospective study, 19% (81/425) of all IPGs done at our institution were bilaterally abnormal (55% of all abnormal IPGs). Acute proximal DVT was found in 26% (14/53) of patients with bilaterally abnormal IPGs who underwent further diagnostic testing. Thirty-five percent of the patients with DVT were found to have either bilateral lower extremity DVT or clots in the inferior vena cava. A numerical score, the venous function index (VFI), was computed for the 101 legs for which further definitive diagnostic evaluations for DVT had been completed. The mean VFI of seven for legs with acute proximal DVT was significantly less than the mean VFI of 13 for legs with no DVT. Fifty percent of legs with a VFI less than or equal to five had DVT, whereas only 7% of legs with a VFI greater than 15 had DVT. The bilaterally abnormal IPG is a common clinical occurrence, is frequently associated with acute DVT, and the VFI is helpful in discriminating legs with acute proximal DVT from normal legs in patients with a bilaterally abnormal IPG.

Adolescent↗