Measurement of right ventricular ejection fraction with krypton-81m in chronic obstructive pulmonary disease

Thirty patients with chronic obstructive pulmonary disease (COPD) and 15 healthy volunteers have been studied to assess the value of measuring right ventricular ejection fraction (RVEF) at rest with a perfusion of krypton-81m (81mKr). With this perfusion, equilibrium RVEF can be measured in a 30 degrees right anterior oblique projection, avoiding a superimposition of cardiac cavities. The average RVEF of the patients with COPD was significantly lower than that of the normal patients (36.3 +/- 9.3% vs 52.6 +/- 3.9%; p less than 0.001). An inverse linear relation was found between mean pulmonary artery pressure (Ppa) and RVEF (r = -0.543; p less than 0.01). The RVEF in a group of 15 patients with COPD and pulmonary hypertension (Ppa greater than 20 mmHg), averaged 30.4 +/- 7.26%, which was significantly lower than that of the other 15 COPD patients with normal Ppa, whose RVEF averaged 42.3 +/- 7.1% (p less than 0.01). Taking a RVEF value less than or equal to 35% as an indicator of pulmonary hypertension, the sensitivity was 80% and specificity was 75%, the predictive value for a positive test was 75%, and for a negative test was 80%. A positive but weak correlation was found between RVEF and PaO2 (r = 0.52; p less than 0.01), SaO2 (r = 0.41; p less than 0.05) and the forced expiratory volume in one second (FEV1) (r = 0.40; p less than 0.05). No correlation was found between RVEF and prior history of right cardiac insufficiency, PaCO2, pH, the ratio FEV1/vital capacity, ECG signs of cor pulmonale and left ventricular ejection fraction.(ABSTRACT TRUNCATED AT 250 WORDS)