Plasma N-terminal proatrial natriuretic factor can predict normal pulmonary capillary wedge pressure in cardiac transplant recipients

BACKGROUND: Plasma N-terminal proatrial natriuretic factor (proANP) is closely related to atrial filling pressure, but this may be distorted in heart transplant recipients. OBJECTIVE: The aim of this study was to examine the usefulness of proANP as a non-invasive marker of cardiac filling pressure in transplanted patients with normal to moderately elevated serum creatinine (s-creatinine). METHODS: Blood was sampled at rest for analysis of proANP from 220 patients 1-13 (median 4) years after orthotopic heart transplantation undergoing routine diagnostic catheterization. RESULTS: In multivariate analysis proANP was significantly positively related to s-creatinine, mean pulmonary capillary wedge pressure (PCWP) and time after transplantation and negatively related to haemoglobin and cardiac index. All the patients with proANP below 1140 pmol/l had normal PCWP (<13 mmHg). The area under the receiver-operating characteristic curve for proANP for the detection of PCWP > 13 mmHg was 0.81. The positive predictive value of proANP for detection of increased PCWP was very low. CONCLUSION: A low proANP had a 100% negative predictive value for increased atrial pressure but the low positive predictive value makes proANP unsuitable as an indicator of increased atrial pressures in heart transplanted patients.