The Clinical Relevance of Circulating Tumor Necrosis Factor-a in Acute Decompensated Chronic Heart Failure Without Cachexia (Materials and Methods)

In: Heart Failure

12 Dec 2013

The Clinical Relevance of Circulating Tumor Necrosis Factor-a in Acute Decompensated Chronic Heart Failure Without Cachexia (Materials and Methods)Study Population

The study population consisted of 29 noncachectic patients (20 men and 9 women; age range, 27 to 79 years; mean 56 ±13 years) with advanced CHF who demonstrated acute decompensation while receiving adequate oral medical therapy, thus requiring admission to the hospital for therapeutic intervention. Patients were excluded if they exhibited any evidence of cachexia or infectious, inflammatory, or neoplastic disease. Cachexia was considered to be present if the percentage of ideal body weight was less than 90% or the serum albumin level was less than 3.0 g/dL. Height and weight were measured and the percentage of ideal body weight (weight/height index) was calculated (actual weight divided by ideal weight) for height and gender. The cause of heart failure was ischemic cardiomyopathy in 13 patients and idiopathic dilated cardiomyopathy in 16 patients.

All patients were in New York Heart Association (NYHA) class IV. Ejection fraction was 16±6% (range, 10 to 30%), mean BP was 82 ± 11 mm Hg (range, 65 to 101 mm Hg), serum sodium level was 135 ±4 mmol/L (range, 126 to 143 mmol/ L), BUN was 30± 13 mg/dL (range, 11 to 61 mg/dL), creatinine was 1.5±0.4 mg/dL (range, 1.0 to 3.0 mg/dL), bicarbonate was 21 ±4 mEq/L (range, 14to30mEq/L), and albumin was 4.0±0.5 g/dL (3.1 to 4.8 g/dL). Outpatient therapy for CHF consisted of furosemide in all patients, angiotensin-converting enzyme inhibitors in 28 patients, hydralazine in 1 patient, digoxin in 21 patients, and long-acting nitrate preparations in 12 patients.

Twenty-five healthy male subjects without evidence of cardiovascular or inflammatory disease (determined by history and physical examination) served as control subjects. The mean age of these normal subjects was 41 years. The study was approved by the hospital’s Institutional Review Committee, and all patients gave informed consent.

Ctjtokine Measurements

Ten milliliters of antecubital venous blood was collected in chilled potassium EDTA tubes from supine, resting subjects for determination of plasma cytokine concentration. Plasma was immediately separated from blood elements by centrifugation, and aliquots were stored at -80°C until assay. All samples were assayed as a batch and analyzed in our laboratory (S.E., A.E.) within 5 months of collection. Concentrations of TNFa were measured with commercially available high-sensitivity enzyme-linked immunosorbent assay (ELISA) kits (Ultrasensitive TNF ELISA; Biosource; Camarillo, Calif). The limit of detection for the assays was 0.5 pg/mL. All samples were run in duplicate with the average of the two measurements reported.

Study Protocol

All CHF patients demonstrated evidence of severe decompensation as evidenced by NYHA class, hyponatremia, and “relative” hypotension. CHF patients were admitted to the hospital, started on a regimen of IV furosemide, and reevaluated within 12 to 16 h. Patients were then divided into two groups: (A) diuretic responsive with predominantly “congestive” features, and (B) diuretic resistant with predominantly “low output state” features (suggested by lower BPs and increased BUN and creatinine) requiring IV inotropes. Diuretic resistance was defined clinically as a failure to achieve improvement of congestive symptoms in 24 h by diuretic therapy alone. Group B was randomly allocated to receive either IV dobutamine or IV milrinone for 72 h. Dobutamine was administered in a concentration of 2.5 pg/kg/min and increased in increments of 2.5 pg/kg/min every 30 min to a maximum dose of 10 pg/kg/min or until significant ventricular ectopy, tachycardia, or hypotension occurred. Milrinone was administered at a standard infusion of 0.375 pg/kg/min and titrated to a maximal dose of 0.75 pg/kg/min within 18 h based on clinical response and side effects. TNFa measurements were performed serially on days 0, 1, and 3 and approximately 1 week after hospital discharge (mean, 11 ±1 days from baseline) on an outpatient basis.

Statistical Analysis

All values are stated as mean±SE. Plasma concentrations of TNFa were compared with CHF patients and normal subjects using the Student’s t test for unpaired observations. Serial concentrations of TNFa in CHF patients were compared with a repeat-ed-measure analysis of variance model, p values <0.05 are considered statistically significant.

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