Biomedical subjects

BK Shively

Publications and source records attributed to BK Shively.

2 recordsLinked to original sources

PubMed2001

Infective Endocarditis.

Despite improvements in antibiotic regimens, patients with infective endocarditis (IE) have a high risk of valve replacement and death. Effective initial treatment depends on two steps: 1) diagnosis of the infecting organism, enabling specific antibiotic therapy, and 2) complete characterization of the anatomic extent of infection. Identification of the infecting organism requires culturing of blood prior to the initiation of antibiotics. Whenever possible, at least three sets of blood cultures should be obtained over 6 to 24 hours and held for 4 weeks if necessary to detect unusual or fastidious organisms. Transesophageal echocardiography (TEE) is usually necessary either to confirm the diagnosis or, most importantly, to identify the local complications of infection, many of which mandate surgery. Despite widespread availability, TEE remains under-used, both for the prevention of unnecessary antibiotic therapy in patients at very low risk for the disease and for the recognition of patients likely to benefit from early surgery. The selection of optimal antibiotic therapy depends on microbiologic data to establish the sensitivities of the specific causative organism. Short courses of antibiotic therapy and outpatient administration of intravenous antibiotics are useful in selected cases.

Journal Article↗

PubMed1998

Evolving Concepts about Aortic Stenosis.

Concepts about the management of aortic stenosis have evolved over the last several years. Concerns about the safety of exercise, positive inotropic drugs, and afterload reduction have been based on the expected exponential relationship of pressure and flow predicted by the Gorlin equation. However, in most patients, even those with severe stenosis, transvalvular pressure gradient increases much less than predicted with increases in cardiac output. Furthermore, data show that exercise testing usually can be performed safely and often provides helpful information about functional status and symptoms. In addition, positive inotropes and afterload-reducing drugs, when initiated cautiously, are often beneficial for these patients. Based on newly available data, physicians are encouraged to wait until symptoms develop before replacing the aortic valve in patients with severe stenosis. Patients with severe aortic stenosis but low transvalvular gradients because of left ventricular dysfunction should have functional testing with dobutamine or nitroprusside. If an increase in flow produces only a minimal increase in transvalvular velocity or pressure gradient, the patient is less likely to benefit from surgery. Risk for noncardiac surgery may not be as high as previously reported in most patients with aortic stenosis; again, functional testing can play an important role in their clinical assessment.

Journal Article↗