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Biomedical subjects

A Askenase

Publications and source records attributed to A Askenase.

9 recordsLinked to original sources
PubMed2000

Hirudin therapy during thrombolysis for venous thrombosis in heparin-induced thrombocytopenia.

Heparin-induced thrombocytopenia (HIT) is the most common drug-related thrombocytopenia. Thromboembolic complications occur in approximately 50% of patients with HIT and result in limb amputation and death in up to 20% and 30% respectively. Because patients with a history of HIT may require future intravenous anticoagulation but have a high-risk of thromboembolism if re-challenged with heparin, alternative therapies are necessary when further anticoagulation is indicated. The use of direct thrombin inhibitors in HIT patients who also require thrombolytic therapy offers unique challenges to anticoagulant monitoring and safety. We present a case of progressive ileofemoral deep venous thrombosis in a patient with a history of HIT in order to review the combined use of hirudin and thrombolysis in this setting.

Anticoagulants↗
PubMed1988

Use of exercise thallium-201 imaging for risk stratification of elderly patients with coronary artery disease.

Although coronary artery disease (CAD) may be asymptomatic, it is the most common cause of death in elderly patients in the U.S. This study examined the prognosis of 449 patients with a mean age of 65 years using exercise thallium-201 imaging. At a follow-up of 25 months, 45 patients underwent coronary artery revascularization, 8 died of cardiac causes and 10 had nonfatal acute myocardial infarctions (AMIs). Thus the total of patients with "hard" events was 18. The events included 12 of 276 patients with atypical or non-anginal symptoms versus 6 of 128 with typical angina (p = not significant); 7 of 51 patients (14%) with Q-wave AMI versus 11 of 353 (3%) without Q-wave AMI (p less than 0.001); 1 of 183 patients (1%) with normal versus 17 of 221 (8%) with abnormal exercise thallium-201 images (p less than 0.002); 10 of 76 patients (13%) with multi vessel thallium-201 abnormality vs 8 of 328 (2%) with no or 1-vessel thallium-201 abnormality (p less than 0.001) and 10 of 96 patients (10%) with greater than or equal to 3 abnormal segments by thallium-201 imaging (total segments = 9) versus 8 of 308 patients with no or less than 3 abnormal segments (p less than 0.001). The number of segments with thallium-201 defects was 1 +/- 2 patients without and 3 +/- 2 in patients with hard events (p less than 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1988

Effect of phase-encoding direction upon magnetic resonance image quality of the heart.

In order to optimize overall cardiac image quality on MR images experienced observers were asked to rank and rate MR images of the heart. The effect of phase-encoding direction and use of cardiac triggering with and without respiratory gating was examined in three orthogonal imaging planes. Results indicate that use of both respiratory and cardiac gating yields the best images. Adequate images of the heart can be obtained without respiratory gating. The quality of images of the heart can be optimized by proper selection of the direction of the phase-encoding gradient. These are improved by using horizontal phase encoding in the sagittal plane and vertical phase encoding in transverse and coronal planes.

Heart↗
PubMed1988

The role of nitrates, beta blockers, and calcium antagonists in stable angina pectoris.

Numerous controlled studies have shown that nitrates, beta blockers, and calcium antagonists are effective in the treatment of stable angina pectoris. The pharmacokinetics, pharmacodynamics, and hemodynamic effects of these agents are different, and thus combination therapy offers additive improvement and also counterbalancing of the undesirable side effects of each drug. The choice of therapy depends on the severity of symptoms, associated diseases, compliance, side effects, and status of left ventricular function. The main mechanism of improvement is a decrease in myocardial oxygen consumption, though an increase in coronary blood flow is another potential reason for the use of calcium blockers. This review considers the properties of these drugs, their mechanism of action, and the results of randomized studies.

Adrenergic beta-Agonists↗
PubMed1988

Dipyridamole cardiac imaging.

Dipyridamole cardiac imaging is a useful alternative technique to exercise stress testing in the evaluation of patients with ischemic heart disease. Intravenous dipyridamole is still in the investigational phase, while oral dipyridamole is widely available. The hemodynamic effects of dipyridamole include an increase in coronary blood flow (due to coronary vasodilation) which is in excess of the increase in myocardial oxygen consumption and cardiac output. The disparity in the increase in coronary blood flow relative to the cardiac output results in an increase in myocardial thallium activity and an increase in the myocardial/background activity ratio. The quality of the thallium images is better or similar to that of exercise thallium images. The optimal dose of intravenous dipyridamole is 0.56 mg/kg, and of the oral dose it is 300 to 400 mg, although higher doses may be necessary in some patients. Analysis of the thallium images has been to a large extent based on visual inspection of the planar images. Delayed images are helpful to establish the nature of the perfusion abnormalities (transient or fixed). The process of redistribution is based on disparate rates of washout from the normal and abnormal zones. The sensitivity and specificity of dipyridamole thallium imaging, whether intravenous or oral, have been shown in a number of studies to be quite adequate and comparable to that achieved during exercise thallium imaging. Dipyridamole two-dimensional echocardiography has also been used in the detection of coronary artery disease; transient (new or worsening of preexisting) wall motion abnormalities have been found to be a specific marker of coronary artery disease. Transmural as well as regional coronary steal phenomena have been postulated as the mechanism for dipyridamole-induced regional wall motion abnormalities. Compared to exercise two-dimensional echocardiography, dipyridamole echocardiography provides high-quality studies and in higher proportions of patients. The results of dipyridamole thallium imaging have also been extremely important in identifying high-risk patients after acute myocardial infarction or patients with peripheral vascular disease undergoing elective vascular surgery; the presence of a dipyridamole-induced perfusion abnormality identifies patients at high risk for future cardiac events. Thus, dipyridamole cardiac imaging is helpful in the diagnosis of coronary artery disease and in risk stratification.

Animals↗
PubMed1987

Thallium imaging with single photon emission computed tomography.

Evaluation of myocardial perfusion with thallium-201 SPECT has advantages over planar images. These advantages are related to better contrast of the images, lack of superimposition of normal and abnormal areas, and a three-dimensional representation of the site and extent of perfusion abnormalities (ischemia, scar, or both). For this reason, rotational tomography is superior to planar imaging in assessing the extent of coronary artery disease, in the detection of small infarcts, and for quantitative measurements. Several techniques have provided accurate quantitative data for infarct sizing both in animals and men. The ability to quantitate infarct size (or ischemia) will be extremely important in studies of myocardial salvage, risk stratification, and longitudinal studies to evaluate the effects of medical and surgical interventions.

Animals↗