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Biomedical subjects

R G Hart

Publications and source records attributed to R G Hart.

At least 73 records · Page 4Linked to original sources
PubMed1995

Oral anticoagulants and intracranial hemorrhage. Facts and hypotheses.

BACKGROUND: Intracranial hemorrhage is the most feared and lethal complication of oral anticoagulation. We review the frequency, predictors, and prognosis of this most common neurological complication of oral anticoagulation. SUMMARY OF REVIEW: Anticoagulation to conventional intensities increases the risk of intracranial hemorrhage 7- to 10-fold, to an absolute rate of nearly 1%/y for many stroke-prone patients. Most (70%) anticoagulant-related intracranial hemorrhages are intracerebral hematomas (approximately 60% are fatal); the bulk of the remainder are subdural hematomas. Predictors of anticoagulant-related intracerebral hematoma are advanced patient age, prior ischemic stroke, hypertension, and intensity of anticoagulation. In approximately half of anticoagulated patients with intracerebral hematoma the bleeding evolves slowly over 12 to 24 hours, and emergency reversal of anticoagulation is crucial. CONCLUSION: Both patient factors and anticoagulation intensity importantly influence the rate of anticoagulation-related intracranial hemorrhage. Patient-related risk factors for this complication overlap with those for ischemic stroke. The risk/benefit equation of anticoagulation for elderly, stroke-prone patients is complex and differs from that for younger patients. The absolute rate reduction (not the relative risk reduction) of ischemic stroke by anticoagulation is the critical issue and must offset accentuation of often lethal brain hemorrhage.

Age Factors↗
PubMed1995

What's new in stroke?

More than 30,000 strokes occur each year in Texas, even though most strokes can be prevented by currently available and well-tolerated therapies. Antiplatelet therapy with aspirin or ticlopidine reduces stroke by about 25% in many patients with transient ischemic attack or initial stroke. Warfarin should not be used routinely for primary cerebrovascular disease but is useful to prevent cardioembolic stroke. Carotid endarterectomy is highly beneficial for patients with symptomatic, high-grade carotid stenosis, but its value for lesser degrees of symptomatic carotid plaque and for asymptomatic stenosis is less clear. Patients with nonvalvular atrial fibrillation have a substantial risk for stroke; most should be treated with warfarin. Risk-factor management (eg, control of hypertension, cessation of smoking, and treatment of hyperlipidemia) is as important as antithrombotic or surgical therapies for most patients with threatened stroke. Treating isolated systolic hypertension in elderly patients reduces stroke risk. Determining the cause of threatened stroke strongly influences preventive management. The tools are at hand to prevent most strokes; the challenge remains to apply them optimally.

Acute Disease↗
PubMed1994

Carotid stenosis in patients with atrial fibrillation. Prevalence, risk factors, and relationship to stroke in the Stroke Prevention in Atrial Fibrillation Study.

BACKGROUND: Several mechanisms contribute to the increased stroke rate of patients with atrial fibrillation (AF). We assessed the frequency of carotid artery stenosis in patients with AF and its relationship to stroke during aspirin or warfarin therapy. METHODS: Carotid ultrasonography was done in 676 patients with AF enrolled in the Stroke Prevention in Atrial Fibrillation Study to detect cervical carotid stenosis of 50% or more of the luminal diameter. The presence of carotid stenosis was correlated with patient features and subsequent stroke during a mean of 2.6 years of follow-up. RESULTS: In patients with AF who were older than 70 years, the frequency of carotid stenosis was 12% in men and 11% in women. Carotid stenosis was independently associated with systolic hypertension (relative risk, 2.4; P = .002), diabetes (relative risk, 1.8; P = .04), and tobacco use (relative risk, 1.8; P = .02). Carotid stenosis did not add significantly to prediction of stroke when analyzed with other clinical risk factors for stroke in patients with AF (relative risk, 1.3; 95% confidence interval, 0.5 to 3.6; P = .55). CONCLUSIONS: Carotid artery stenosis of 50% or more occurs in about 12% of elderly patients with AF, reflecting the substantial prevalence of hypertension and diabetes in these patients. Carotid stenosis was not usefully predictive of stroke in patients with AF who were given aspirin or warfarin. Routine ultrasonography to detect carotid stenosis does not appear warranted in patients with AF without previous symptoms of brain ischemia.

Aged↗
PubMed1994

Antithrombotic therapies for stroke prevention.

Aspirin is the most widely used antiplatelet agent, reducing nonfatal ischemic stroke by 22%. There is increasing evidence that the efficacy of aspirin may vary with the etiologic subtype of stroke. Although the cost and side effects have limited the use of ticlopidine, patients who are intolerant of aspirin and those experiencing transient ischemic attack or stroke during aspirin therapy should be given ticlopidine. Patients with atrial fibrillation have a five-fold increased risk of stroke and require prophylactic therapy with warfarin or aspirin. Aspirin is less effective than warfarin in preventing atrial fibrillation-associated stroke, but the higher risk of hemorrhagic complications and frequent monitoring associated with warfarin must be considered. Clinical and echocardiographic predictors of increased thromboembolic risk in atrial fibrillation patients have been identified and may direct the treatment choice.

Anticoagulants↗
PubMed1994

Prevention of stroke in atrial fibrillation: an update.

Atrial fibrillation (AF) is associated with a substantially increased risk of ischemic stroke. Recently, five randomized clinical trials independently assessed the value of antithrombotic prophylaxis in AF patients. The rate of ischemic stroke in patients receiving a placebo averaged 5% per year. On aggregate, anticoagulation (INR 1.5 to 4.0) was shown to substantially (mean = 70%) reduce the risk of arterial thromboembolism. The effect of acetylsalicylic acid (ASA) studied in two trials was not uniform, but the efficacy of ASA was less than anticoagulation. ASA appeared to prevent nonembolic strokes better than embolic strokes in AF patients. The characterization of subgroups of AF patients who have relatively high or low absolute stroke rates determines which patients gain greater or lesser benefit from anticoagulant therapy. A multivariate analysis of a large cohort of placebo-treated patients yielded three independent clinical predictors of an increased risk of arterial thromboembolism: a history of hypertension, recent (within three months) congestive heart failure and prior transient ischemic attack (TIA) or stroke, and two echocardiographic predictors--left atrial size of greater than 4.6 cm and impaired left ventricular function. At present, anticoagulation with warfarin (INR 2 - 3) is recommended in AF patients with one or more of these risk factors. The European Atrial Fibrillation Trial studied only AF patients with prior stroke and TIA and confirmed the superiority of warfarin over ASA for secondary prevention.

Aged↗
PubMed1994

Ticlopidine hydrochloride use and threatened stroke.

Ticlopidine hydrochloride is an antiplatelet agent of proven antithrombotic efficacy that in December 1991 became available for general clinical use in the United States. The relative value of ticlopidine compared with aspirin, also an effective antiplatelet agent, has become a key clinical issue. Whereas ticlopidine is somewhat more effective than aspirin for preventing stroke in certain populations, it is also more expensive and potentially toxic. We recommend its use for patients with threatened stroke who are intolerant of aspirin and for patients who have cerebral ischemic symptoms despite aspirin therapy. Patients surviving major ischemic stroke make up a third group for whom ticlopidine use may be recommended in preference to aspirin. The use of ticlopidine rather than aspirin in patients with other cerebrovascular conditions is not strongly supported by existing data. The risk-benefit-cost equation involving ticlopidine versus other antithrombotic therapies is complex, rendering a wide range of acceptable management practices. If reliable laboratory monitoring for neutropenia during the first 3 months of therapy is not feasible, ticlopidine should not be used.

Aspirin↗
PubMed1993

Ischemic stroke in patients with atrial fibrillation: effect of aspirin according to stroke mechanism. Stroke Prevention in Atrial Fibrillation Investigators.

Ischemic strokes occurring in patients with nonrheumatic atrial fibrillation are due to a variety of mechanisms, not exclusively to cardiogenic embolism. Without knowledge of antithrombotic therapy assignment, we categorized strokes in the Stroke Prevention in Atrial Fibrillation Study as presumed cardioembolic or noncardioembolic. We then compared patient clinical and echocardiographic variables, as well as the efficacy of aspirin prophylaxis, for each stroke type. Of 71 ischemic strokes, we categorized 46 (65%) as cardioembolic, 13 (18%) as noncardioembolic, and 12 (17%) as of uncertain cause. Patients developing noncardioembolic strokes, relative to cardioembolic strokes, were more commonly men (p = 0.005) and were more likely to have left ventricular wall motion abnormalities by two-dimensional echocardiography (p = 0.002). Aspirin reduced the occurrence of strokes categorized as noncardioembolic significantly more than it did those categorized as cardioembolic (p = 0.01). These results emphasize the value of considering stroke mechanisms in therapeutic trials of antithrombotic agents and suggest a differential effect of aspirin according to mechanism.

Aged↗
PubMed1993

Flexor tendon injuries of the hand.

Flexor tendon injuries can be problematic injuries from the time of occurrence until the patient returns to full and complete recovery. There are many misadventures that can occur along the way. The emergency physician must be keenly aware of the anatomy involved, and a careful history and physical examination must be performed. The diagnosis may be obvious or subtle, and the emergency physician must methodically search for the unsuspected injury. An appropriate referral should be initiated soon after an injury is determined. The hand surgeon has many considerations and obstacles in flexor tendon repairs, but good to excellent results can be expected in up to 80% of patients if the emergency physician and the hand surgeon work together to ensure an optimal patient outcome.

Emergencies↗
PubMed1993

Extensor tendon injuries of the hand.

Extensor tendon injuries are often initially evaluated and diagnosed in the Emergency Department. These injuries may be painfully obvious or frightfully subtle, but if the emergency physician has a firm understanding of the anatomy involved and he or she embarks on a careful and complete history and physical examination, the diagnosis should be made. There are various considerations in the ultimate treatment and outcome for the patient, and the patient's best interests are served when the emergency physician provides the initial appropriate treatment and proper disposition.

Emergencies↗
PubMed1993

Fingertip and nail bed injuries.

Nail bed and fingertip injuries are commonly seen in the Emergency Department. Each of these injuries must be evaluated carefully not only for the acute situation but for the possible long-term effects. Nail bed injuries must be appropriately diagnosed and treated initially because a secondary repair is often unsatisfactory. Fingertip injuries must provide the patient with a sensitive fingertip with sufficient length for effective use of the finger. The initial care and treatment are vital for the best patient outcome.

Acute Disease↗