RESUMEN
OBJECTIVE: To identify the mechanisms which influence the development of cardiac insufficiency in Paget's disease of bone (PD). METHODS: In this hospital-based case-control study 23 consecutive, recently diagnosed and untreated PD patients were compared against 23 controls frequency-matched by sex, age and body index. All subjects underwent non-invasive assessment of cardiac function by two-dimensional Doppler echocardiography. Calcium, phosphate, and creatinine were determined in the serum and urine, along with alkaline phosphatase and hydroxyproline excretion, two biochemical parameters of PD activity. RESULTS: Peripheral vascular resistance proved lower (1604.9 +/- 390.1 vs 1801.2 +/- 421.0) and the stroke volume higher in PD patients (67.2 +/- 14.4 vs 56.0 +/- 8.6; p = 0.07) compared with controls. These differences were greater (1504.7 +/- 289.9 and 71.0 +/- 6.2) and attained statistical significance (p = 0.008) when the subgroup with more extensive skeletal disease only was considered. A moderate correlation was observed between hydroxyproline excretion and the E/A ratio (r = 0.45; p = 0.03), peripheral vascular resistance (r = -0.42; p = 0.04), and diastolic arterial pressure (r = -0.42; p = 0.04). The final model obtained via multivariate analysis identified both urinary hydroxyproline and age as predictive variables linked to peripheral vascular resistance. CONCLUSION: In the early phases of PD there is a trend towards a reduction in peripheral vascular resistance. If this persists, it may lead progressively to increased cardiac output, which is mainly influenced by the degree of turnover impairment and the age of the individual.