Misdiagnosis and Mistreatment of Pulmonary Arterial Hypertension (PAH) Due to Under-Occlusion during Right Heart Catheterization (RHC)

Objectives 1) Outline a case in which suspected PAH was falsely diagnosed and treated as pulmonary venous hypertension due to incorrect RHC data 2) Reinforce importance of standardized technique during RHC to ensure accurate hemodynamic data 3) Emphasize importance of reviewing source data when there is a discrepancy between diagnostic data and the clinical picture. A 59 year old female with scleroderma, non-ischemic cardiomyopathy (30-35% EF), GERD, and T2DM presented from an outside hospital for evaluation of chronic dyspnea. Initial RHC data (RHC 1) indicated pulmonary venous hypertension and cardiogenic shock. Diuretics, afterload reduction, and Milrinone were initiated. However, her echocardiogram showed an RV:LV ratio of 1.8 (Image 1) and right ventricular outflow tract (RVOT) doppler notching (Image 2), consistent with PAH physiology. Due to patient deterioration and a discrepancy between echocardiographic and hemodynamic data, a repeat RHC was performed. The results (RHC 2) were significantly different from prior and diagnostic of PAH, which was consistent with the initial echocardiographic findings and the clinical picture. Although RHC is the definitive diagnostic tool for diagnosing PAH, it is prone to operator discrepancies. The initial RHC data was incorrect due to under-occlusion, a phenomenon that can occur in patients with significant PAH due to enlargement of the proximal pulmonary artery. Tracings 1 and 2 show the wedge pressures from the initial and subsequent RHC, respectively. There is clearly a significant difference in the reported left sided filling pressure. Additionally, RHC 1 data shows the wedge pressure to be higher than the diastolic pulmonary artery pressure, indicating an erroneous wedge pressure due to partial or incomplete pulmonary artery occlusion. Many centers confirm wedge position by checking a wedge saturation. A standardized technique for performing RHC could help mitigate operator discrepancies. After starting Sildenafil for PAH, the patient began to improve and was eventually discharged home on Milrinone, Sildenafil, and oral diuretics. This case highlights the importance of reviewing all source data especially when there is discrepancy between different diagnostic data and the clinical picture.