EFFECT OF LONG-TERM ANGIOTENSIN-CONVERTING ENZYME-INHIBITOR THERAPY ON ARTERIAL OXYGEN-SATURATION IN PATIENTS WITH MILD-TO-MODERATE HEART-FAILURE

Study Objective. To evaluate the effects of angiotensin-converting enz yme (ACE) inhibition on continuous pulse oximetry recordings of arteri al oxygen saturation (SpO2). Design. Open-label study Setting. Cardiol ogy clinics at two large teaching hospitals. Patients. Eight patients with New York Heart Association Functional Class (NYHA FC) II-III hear t failure. Interventions. Patients were studied after an ACE inhibitor washout (baseline, B), and after 3 months following resumption of the rapy (ACEI). Measurements and Main Results. Monitoring times for B and ACEI were approximately 22 hours. Reduction trends were observed for number (190 +/-170 vs 125 +/- 67 B vs ACEI), magnitude (8.2 +/- 1.4% v s 7.5 +/- 1.8%), and duration (2.45 +/- 2.8 vs 1.35 +/- 0.8 min) of de saturations/monitoring period, and for nadir SPO2/desaturation (88.1 /- 1.5% vs 89.9 +/- 3.3%). The B desaturation index [(cumulative desat uration time/monitoring period time) x 100, a measure of hypoxic stres s or burden] decreased from 19.4 +/- 8.1% to 11.9 +/- 8.1% at ACEI (p= 0.024). Conclusion. Long-term ACE inhibitor therapy improves the profi le of SpO2 values over time in patients with NYHA FC II-III heart fail ure.