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Biomedical subjects

Timothy A Mixon

Publications and source records attributed to Timothy A Mixon.

10 recordsLinked to original sources
PubMed2004

Assessment of anticoagulation using activated clotting times in patients receiving intravenous enoxaparin during percutaneous coronary intervention.

Enoxaparin is being used more frequently in patients undergoing percutaneous coronary intervention (PCI). In this study, we determined the effect of intravenous enoxaparin on activated clotting time (ACT) measurements in the setting of PCI. In 67 consecutive patients, either 1 mg/kg intravenous enoxaparin alone was given for anticoagulation or 0.75 mg/kg given in patients receiving eptifibatide. ACT was measured before and 5 min following enoxaparin administration. After 1 mg/kg enoxaparin (n = 22), mean ACT increased from 122 +/- 22 to 199 +/- 20 sec. After 0.75 mg/kg enoxaparin and eptifibatide (n = 45), mean ACT increased from 125 +/- 22 to 194 +/- 24 sec. The mean increase in ACT was 77 +/- 26 sec in the 1 mg/kg group and 69 +/- 23 sec in the 0.75 mg/kg group (both P values < 0.0001). Moreover, in a subgroup of 26 patients, there was an excellent correlation (r = 0.86) between ACTs and the ENOX test, a new point-of-care test for assessing enoxaparin anticoagulation. None of the patients had transient abrupt closure, thrombus formation, major bleeding, or required urgent revascularization. Intravenous enoxaparin at clinically relevant doses with and without eptifibatide increases ACT levels at 5 min in patients undergoing PCI. These data suggest the ACT may be useful in the assessment of anticoagulation by enoxaparin.

Angioplasty, Balloon, Coronary↗
PubMed2004

Temporary coronary guidewire pacing during percutaneous coronary intervention.

Temporary pacing is occasionally required during percutaneous coronary artery interventions. This can be accomplished by the insertion of a temporary transvenous pacemaker wire into the right ventricle, but there is some risk and inconvenience associated with this approach. Temporary pacing using the coronary artery guidewire was described in 1985 but is used infrequently. Using currently available equipment, we evaluated guidewire pacing in 26 patients. Guidewire pacing was successful in all patients, but not with all coronary guidewires at acceptable ventricular capture thresholds. No complications occurred from guidewire pacing. Bench testing of multiple different wires showed several with very high resistances likely unsuitable for clinical use. Temporary guidewire pacing is easily performed and should be considered as an alternative to the separate placement of a temporary transvenous pacemaker.

Adult↗
PubMed2004

Recombinant platelet factor 4 for heparin neutralization.

Protamine sulfate has been used for many years to reverse the effects of unfractionated heparin, but it can cause hemodynamic changes and other serious side effects. Platelet factor 4 (PF4) is a naturally occurring protein synthesized in megakaryocytes and eventually stored in the alpha granules of platelets for later release. Although the complete physiologic role of PF4 is unknown, it is highly effective for the neutralization of heparin anticoagulation. Several preliminary animal studies and trials using blood obtained from cardiopulmonary bypass circuits suggested recombinant PF4 (rPF4) would be an effective alternative to protamine. In the first open-label, phase 1 human study, patients received rPF4 in doses of 0.5, 1.0, 2.5, or 5.0 mg/kg over 3 minutes to reverse heparin anticoagulation after diagnostic cardiac catheterization. There were no important hemodynamic changes and the rPF4 was highly effective in neutralizing heparin. Serial measurements of rPF4 levels showed a monophasic elimination pattern with a serum half-life of 25.5 +/- 13.5 minutes that was independent of dose administered. A randomized and blinded trial comparing rPF4 to protamine confirmed the safety and effectiveness of rPF4. Although rPF4 was initially being evaluated as a clinical alternative to protamine, it is not currently being developed for general clinical use.

Aged↗
PubMed2004

Abnormal diastolic flow demonstrated by color M mode echocardiography in hypertrophic cardiomyopathy with mid-ventricular cavity obliteration.

We report a case of a 55-year-old woman who presented with ventricular tachycardia and myocardial infarction. Investigations revealed no disease of the epicardial coronary arteries, but a diagnosis of hypertrophic cardiomyopathy with mid-cavitary dynamic obstruction was made. Detailed echocardiographic examination, including pulse-wave Doppler and Color M Mode recordings revealed unusual components of diastolic dysfunction.

Blood Flow Velocity↗
PubMed2003

Patient care before and after percutaneous coronary artery interventions.

Care of the patient before and after percutaneous coronary interventions has changed largely because of the increased use of stents. Important patient management issues include the evaluation of chest pain after the procedure, recognition of acute vessel closure during the periprocedural period, management of the vascular access site, and prevention of contrast-induced renal dysfunction. Risk factor modification and drug therapies are important interventions for the secondary prevention of coronary events. Functional testing has a meaningful role in the evaluation of some patients after coronary intervention. It is important for the specialist in internal medicine to have a firm working knowledge of the various aspects of patient care before and after these procedures because their role in the management of these patients is increasing.

Acute Kidney Injury↗
PubMed2003

Intestinal obstruction mimicking acute myocardial infarction.

A 64-year-old woman presented at our institution with abdominal pain. An electrocardiogram suggested the possibility of acute anteroseptal myocardial infarction. Her medical history included esophageal reconstruction with use of a jejunal conduit in the anterior mediastinum. Echocardiography revealed a distended jejunal conduit, which was compressing the right ventricle. Once the cause was identified, nasogastric suction was initiated and the symptoms and electrocardiographic changes resolved.

Abdominal Pain↗