Impact of Esophageal Pressure Measurement on Pulmonary Hypertension Diagnosis in Patients With Obesity

Background: Elevated intrathoracic pressure could affect pulmonary vascular pressure measurements and influence pulmonary hypertension (PH) diagnosis and classification. Esophageal pressure (P_es) measurement adjusts for the increase in intrathoracic pressure, better reflecting the pulmonary hemodynamics in patients with obesity.

Research question: In individuals with obesity, what is the impact of adjusting pulmonary hemodynamic determinations for P_es on PH diagnosis and classification? Can P_es be estimated by positional or respiratory hemodynamic changes?

Study design and methods: In this prospective cohort study, we included patients with obesity who underwent right heart catheterization and demonstrated elevated pulmonary artery wedge pressure (PAWP; ≥ 12 mm Hg). After placement of an esophageal balloon, we performed pressure determination using an air-filled transducer connected to a regular hemodynamic monitor. We measured pulmonary pressures changes when sitting and the variations during the respiratory cycle.

Results: We included 53 patients (mean ± SD age, 59 ± 12 years; mean ± SD BMI, 44.4 ± 10.2 kg/m²). Supine end-expiratory pressures revealed a mean pulmonary artery pressure of > 20 mm Hg in all patients and a PAWP of >15 mm Hg in most patients (n = 50). The P_es adjustment led to a significant decrease in percentage of patients with postcapillary PH (from 60% to 8%) and combined precapillary and postcapillary PH (from 34% to 11%), at the expense of an increase in percentage of patients with no PH (0% to 23%), isolated precapillary PH (2% to 25%), and undifferentiated PH (4% to 34%).

Interpretation: Adjusting pulmonary hemodynamics for P_es in patients with obesity leads to a pronounced reduction in the number of patients who receive a diagnosis of postcapillary PH. Measuring P_es should be considered in patients with obesity, particularly those with elevated PAWP.