Diagnostic usefulness of passive leg raising test for detection of heart failure with preserved ejection fraction compared to cycle ergometer exercise (invasive hemodynamic study)

Abstract

Abstract Background Invasive diastolic stress test using cycle ergometer is gold standard for diagnosis of heart failure with preserved ejection fraction (HFpEF) by demonstrating elevation of left ventricular end diastolic pressure (LVEDP) during exercise. It is well known that passive leg raising increases preload and augments LVEDP in HFpEF patients. However correlation between passive leg raising induced increase of LVEDP and cycle ergometer exercise induced increase of LVEDP is not well established. Therefore we investigated whether passive leg raising test could substitute cycle exercise test for diagnosis of HFpEF. Method Forty-five patients with unexplained dyspnea and ejection fraction >50% underwent invasive exercise test. After measuring baseline LVEDP in supine position using pigtail catheter through radial artery approach, LVEDP during passive leg raising was evaluated. Then exercise LVEDP was measured after 3 minutes of 20 watt supine cycle ergometer exercise. Patients with normal resting LVEDP <16mmHg were enrolled. Patients with cycle ergometer exercise LVEDP >26mmHg were classified as HFpEF and exercise LVEDP <26mmHg were defined as noncardiac dyspnea. Results Among 45 patients with unexplained dyspnea with preserved EF, 30 patients with ergometer exercise LVEDP >26mmHg were grouped as HFpEF and 15 patients with exercise LVEDP <26mmHg grouped as noncardiac dyspnea (NCD). Resting LVEDP was higher in HFpEF than NCD (14±2mmHg vs 11±3mmHg, P=0.01) but there was substantial overlap (figure 1) showing poor differentiation power of resting LVEDP. Passive leg raising increased LVEDP in both HFpEF and NCD but this was more marked in HFpEF group than in NCD group with minimal overlap (24±4mmHg vs 17±2mmHg, P<0.001) (figure 2). Passive leg raising LVEDP was well correlated with cycle ergometer exercise LVEDP (R2=0.60, P<0.01). The best cutoff value for passive leg raising LVEDP to detect HFpEF was 20mmHg (sensitivity, 0.87; specificity, 1.00), giving an area under the curve of 0.93 (95% confidence interval, 0.80 to 0.99). Positive predictive value of passive leg raising LVEDP >20mmHg for diagnosis of HFpEF was 96% and negative predictive value was 77%. Conclusion Passive leg raising induced augmentation of left ventricular end diastolic pressure (LVEDP) was well correlated with cycle exercise induced elevation of LVEDP in HFpEF patients. Passive leg raising test may be used for detecting HFpEF with good accuracy in substitution for cycle ergometer exercise test. Funding Acknowledgement Type of funding source: None