Preserved Atrial Natriuretic Peptide Secretory Function After Cardiac Transplantation Randall C. Starling, MD, Thomas M. O’Dorisio, MD, William 6. Malarkey, MD, Kevin D. Murray, MD, P. David Myerowitz, MD, and Robert J. Cody, MD

The purpose of this investigation was to determine whether atrial natriuretic peptide (ANP) secretory function,is preserved after cardiac transplantation. Thirteen hemodynamieally stable outpatients performed supine exercise on a bicycle an average of 7 months after orthotopic cardiac transplantation. Right atrial pressure increased 2.29fold (6 f 1 to 13 f 2 mm Hg) and pulmonary (11 f 1 to 23 f 7 artery wedge pressure P&fold mm Hg) with exercise in the transplant recipients. Resting venous ANP level (114 f 19 Pg/ml) and peak exercise venous level (373 f 61 pg/ml) was elevated in transplant recipients (p 160 beats/min with exercise,and the time required to reach exhaustion was 21 f 1 minutes. Intracardiac pressureswere not obtained in the control population. Venous ANP levels (superior vena cava or peripheral vein) were used for comparisonsbetweenthe control and study population. The protocol was approved by the Human SubjectsReview Committee and all subjectsgave informed consent. The ANP levels were determined by a modification of the a-human ANP radioimmunoassaykit produced by Peninsula Laboratories. The sensitivity of the assay in our laboratory is 20 pg/ml of plasma. The intra- and interassay coefficients of variation for this radioimmunoassaywere 4 and 22%, respectively.The values were calculated using control-spiked samplesof plasma previously stripped with charcoal and assayedat 3 separate known concentrations on the standard curve. Unextracted charcoal-treated plasma was added to the assay curve and all plasma samples were assayedwith nonspecific (e.g., no ANP antibody added) tubes to correct for further nonspecific protein binding. Mdistics: Measurements are expressed as mean values,with the standard error of the mean as the index of dispersion.The unpaired Student’s t test was used to compare the resting ANP levels in the normal and transplant patient groups. Analysis of variance was performed on the ANP levels obtained from different intravascular sample sites. Rest and peak exercise ANP levels among matched patient groups were compared using the paired Student’s t test. Simple linear regression was used to determine the relation between the ANP level and hemodynamic measures.Results were consideredsignificant at p

Preserved atrial natriuretic peptide secretory function after cardiac transplantation.

The purpose of this investigation was to determine whether atrial natriuretic peptide (ANP) secretory function is preserved after cardiac transplantat...
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