The purpose of this study was to evaluate pulmonary and cardiovascular parameters during ergometry which are involved in the decreased exercise ability of IPF patients and to determine if these parameters have any prognostic value about surveillance.
Nineteen patients with IPF were studied at the day of admission with spirometry and measurements of arterial blood gasses. Right heart catheterization and ergometry was performed at the next day. Patients underwent an incremental exercise test (10Watt/2min). All patients received standard therapy for IPF and were followed untill death, for an average of 46±11 months.
Maximal predicted oxygen uptake (VO2max%) was 41±13.7%predicted and all patients demonstrated significant arterial (PaO2) and central venous (SVO2) desaturation during exercise. Patients with IPF had lower cardiac output (COmax=8.47±2.5L/min) at the same work level than normal subjects; as well as more pulmonary hypertension (PAPm=37.2±15.5mmHg) and elevated pulmonary vascular resistance (PVR=241±331.2 dynòsec/cm-5). The difference (δ) between values at rest and peak exercise for cardiac output (δCO) was significantly correlated with δSVO2 (r=0.617 p=0,004) and δSVR (r=0.616 p=0.004). Based on Kaplan-Meier and ROC tests we found that the values of δCO=3.1L/min and δSVO2 =32% were significant prognostic factors of survival in IPF patients (x2=4.26 p=0.039 and x2=4.28 p=0.038 respectively).
The predicting factors for survival in IPF patients during ergometry at the peak exercise level were a central venous oxygen desaturation rate lower than 32% and an increase in cardiac output over 3.1 L/min.
The elevation of PAPm and persistent high values of PVR during exercise may affect right heart function but they are not useful prognostic factors of survival. The degree of central venous desaturation is probably more strongly correlated with deleterious effects on cardiac and body homeostasis, or reflects more precisely the co-impairment of the left cardiac function in IPF patients during ergometry.
Stavros Tryfon, No Financial Disclosure Information; No Product/Research Disclosure Information