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Biomedical subjects

Robert C Pendleton

Publications and source records attributed to Robert C Pendleton.

4 recordsLinked to original sources

Left ventricular hypertrophy in severe obesity: interactions among blood pressure, nocturnal hypoxemia, and body mass.

Obese subjects have a high prevalence of left ventricular (LV) hypertrophy. It is unclear to what extent LV hypertrophy results directly from obesity or from associated conditions, such as hypertension, impaired glucose homeostasis, or obstructive sleep apnea. We tested the hypothesis that LV hypertrophy in severe obesity is associated with additive effects from each of the major comorbidities. Echocardiography and laboratory testing were performed in 455 severely obese subjects with body mass index 35 to 92 kg/m(2) and 59 nonobese reference subjects. LV hypertrophy, defined by allometrically corrected (LV mass/height(2.7)), gender-specific criteria, was present in 78% of the obese subjects. Multivariable regression analyses showed that average nocturnal oxygen saturation <85% was the strongest independent predictor of LV hypertrophy (P<0.001), followed by systolic blood pressure (P<0.015) and then body mass index (P<0.05). With regard to LV mass, there were synergistic effects between hypertension and body mass index (P interaction <0.001) and between hypertension and reduced nocturnal oxygen saturation. Severely obese subjects had normal LV endocardial fractional shortening (35+/-6% versus 35+/-6%) but mildly decreased midwall fractional shortening (15+/-2% versus 17+/-2%; P<0.001), indicating subtle myocardial dysfunction. In conclusion, more severe nocturnal hypoxemia, increasing systolic blood pressure, and body mass index are all independently associated with increased LV mass. The effects of increased blood pressure seem to amplify those of sleep apnea and more severe obesity.

Adult↗

The treatment of venous thromboembolism in special populations.

Anticoagulant therapy for the typical venous thromboembolism patient is straightforward with predictably favorable outcomes. However, for certain patients with venous thromboembolism, there remains uncertainty and controversy about optimal treatment. These controversial areas include venous thromboembolism patients with: heparin resistance, renal insufficiency, morbid obesity, cancer, antiphospholipid antibody syndrome, recurrent thrombosis despite appropriate anticoagulation, and patients with unprovoked VTE who may or may not benefit from thrombophilia testing. This review summarizes the current data for these special patient populations with venous thromboembolism and provides our recommendations for management.

Anticoagulants↗

Incidence and economic implications of heparin-induced thrombocytopenia in medical patients receiving prophylaxis for venous thromboembolism.

STUDY OBJECTIVES: To determine the incidence of heparin-induced thrombocytopenia (HIT) in patients admitted to a medical service who were given unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) to prevent venous thromboembolism, the incremental cost of developing HIT, and the cost consequences of using LMWH to prevent venous thromboembolism in medical patients. DESIGN: Retrospective analysis with a nested case-control. SETTING: University-affiliated tertiary-care hospital. PATIENTS: A total of 10,121 adult medical patients admitted between August 1, 2000, and November 2, 2004, received UFH or LMWH to prevent venous thromboembolism during their admission. From these, patients with immune-mediated HIT were identified and served as case patients, and 3-5 matched control patients were identified for each case patient. MEASUREMENTS AND MAIN RESULTS: The development of HIT was determined for patients who received LMWH and for patients who received UFH. Costs were compared between the patients with HIT and the matched control patients. The cost of using LMWH to prevent venous thromboembolism was compared with the cost of using UFH. In patients receiving UFH and those receiving LMWH, the incidence of HIT was 0.51% (43/8420) and 0.084% (1/1189), respectively (p=0.037), with an overall incidence of 0.43% (44/10,121). Admissions that included development of HIT incurred an average cost of 56,364 dollars compared with 15,231 dollars (p<0.001) for admissions without HIT. Using LMWH to prevent venous thromboembolism in medical patients cost 13.88 dollars less per patient than using UFH. CONCLUSIONS: For the prophylaxis of venous thromboembolism, LMWH was associated with a lower incidence of HIT than UFH in medical patients. An admission during which the patient develops HIT costs significantly more than an admission during which the patient does not develop HIT. Low-molecular-weight heparin is cost-effective for prevention of venous thromboembolism in medical patients.

Anticoagulants↗