Dosing of unfractionated heparin in obese patients with venous thromboembolism.

BACKGROUND: Aggressive weight-based dosing guidelines help achieve prompt therapeutic anticoagulation in patients with venous thromboembolism (VTE). While obese patients with VTE face an increased risk of recurrence, physicians typically resist prescribing doses two to three times the usual dose because of concern about bleeding complications. OBJECTIVE: To examine the use of unfractionated heparin in obese patients with VTE at an academic teaching hospital in order to document the extent and pattern of underprescribing in this high-risk patient population. DESIGN: Three-year, cross-sectional consecutive case series. PATIENTS: Adult inpatients with VTE and a body mass index ≥30 kg/m(2) who were treated with unfractionated heparin. MEASUREMENTS: Time to achievement of therapeutic anticoagulation (activated partial thromboplastin time >60 s) and gap between recommended and prescribed heparin doses. RESULTS: Time to attainment of therapeutic anticoagulation exceeded 24 h in 29% of study patients (n = 84) and exceeded 48 h in 14% of patients. In 75 patients (89%), the prescribed bolus dose fell below the recommended dose of 80 units/kg, and in 64 patients (76%) the initial continuous infusion fell more than 100 units/h below--in some cases more than 1000 units/h below--the recommended dose of 18 units/kg/h. There was a significant correlation between time to therapeutic anticoagulation and initial infusion dose (Spearman r = -0.27; p < 0.02). Each decrease of 1 unit/kg/h translated to a delay ranging from about 0.75 h to 1.5 h over the range of prescribed doses (6 to 22 units/kg/h). CONCLUSIONS: A substantial proportion of obese patients treated with unfractionated heparin experienced a delay >24 h in achieving adequate anticoagulation, and the vast majority received an inadequate heparin bolus or initial continuous infusion (or both) according to current dosing guidelines.

Aortic valve replacement in octogenarians.

In a consecutive series of 1109 patients undergoing aortic valve replacement (AVR) between January 1988 and December 1990, there were 48 patients (33 female, 15 male) over 80 years of age (mean age 83.5 years, median 82.9 years). Of those, 33 had aortic stenosis and 15 combined aortic valve disease, with additional coronary artery disease being present in 36. Isolated AVR was performed in 25 patients, and it was combined with coronary venous bypass grafting, with 1-4 (mean 1.8) peripheral anastomoses in 23. Two patients died within 30 days (early mortality 4.2%). Non-fatal complications included one hemiparesis, four transient cerebral disorders, two cases of pneumonia which led to ventilatory assistance, three rethoracotomies because of postoperative bleeding, 15 tachycardias and one transient AV block. Late results were obtained after a median follow up time of 22 months. There were eight late deaths (four cardiac related, four not related) and a low incidence of non-fatal complications (two episodes of gastrointestinal bleeding while on oral anticoagulation, one cerebral transient ischemic attack and one acute left ventricular failure). Nine patients are in NYHA Class I, 12 in Class I-II, 11 in Class II, three in Class II-III and three in Class III. Of the surviving 38 patients, four are currently living in a home for the aged or a nursing home, while all the others are living in their own homes and are able to sustain a relatively independent life-style. We conclude that in very old patients with aortic valve disease, AVR can be performed with low mortality and few non-fatal complications.