Abstract 17438: Misclassification of the Cause of Dyspnea by Resting Right Heart Catheterization: the Impact of Invasive Cardiopulmonary Exercise Testing

Abstract

Introduction: Supine resting right heart catheterization (srRHC) is the standard method to differentiate pulmonary arterial hypertension (PAH) and heart failure with preserved ejection fraction (HFpEF), but most such patients complain of symptoms during exercise. We hypothesized that the upright invasive exercise phenotype of patients with unexplained exertional intolerance provides a distinct and additive perspective compared with supine resting RHC in the diagnosis of PAH and HFpEF. Methods: We reviewed results of consecutive patients with unexplained effort intolerance who underwent same day sequential srRHC and invasive cardiopulmonary exercise testing (iCPET) between March 2011 and October 2013. At rest, patients were classified with PAH if mean pulmonary arterial pressure (mPAP) ≥ 25 mmHg and pulmonary arterial wedge pressure (PAWP) ≤ 15 mmHg; as HFpEF if PAWP > 15 mmHg; and as normal if none of the above hemodynamic criteria were met. At peak exercise, patients were categorized as exercise-induced PAH (eiPAH), exercise HFpEF (eHFpEF), normal (eNormal), or peripheral limitation according to the criteria displayed in the table. Results: Of 255 patients, 212 (83%) had normal srRHC. Of these, 46 (22%) had an abnormal iCPET result: eiPAH (n=24), eHFpEF (n=22). A resting mPAP > 18 mmHg discriminated eiPAH reasonably well (ROC AUC: 0.75; 95%CI: 0.67-0.83). Of those with abnormal srRHC, iCPET reclassified diagnosis for 16/43 (37%). Of the 30 patients who had HFpEF by srRHC, 12 (40%) had a normal cardiac hemodynamic profile during upright maximum exercise. 4 (31%) of the 13 patients with PAH at rest had no suggestion of intrinsic pulmonary vascular disease during exercise (3 eHFpEF and 1 non-cardiac limitation) with iCPET. Conclusions: In patients with exertional intolerance, iCPET reveals hemodynamic abnormalities which are overlooked with resting RHC and reclassifies a significant subset of apparent PAH and HFpEF patients by srRHC.