Increased biventricular hemodynamic forces in precapillary pulmonary hypertension

Area of Science:

• Cardiology
• Biomedical Engineering
• Medical Physics

Background:

• Precapillary pulmonary hypertension (PH_precap) is characterized by elevated pulmonary vascular pressure and resistance, leading to poor patient prognosis.
• Understanding the underlying pathophysiological mechanisms is crucial for improving treatment strategies.
• Ventricular hemodynamic forces (HDF) may serve as an early marker of cardiac dysfunction and aid in evaluating treatment efficacy.

Purpose of the Study:

• To investigate differences in biventricular hemodynamic forces (HDF) between patients with PH_precap and healthy controls.
• To explore the potential of HDF as a complementary diagnostic tool in precapillary pulmonary hypertension.

Main Methods:

• Cardiac magnetic resonance imaging (MRI) with 4D flow was performed on 20 patients with PH_precap and 12 healthy controls.
• Biventricular HDF were computed in three spatial directions throughout the cardiac cycle using Navier-Stokes equations.
• HDF were indexed to stroke volume (N/l) for comparison between groups.

Main Results:

• Patients with PH_precap exhibited significantly larger biventricular HDF compared to healthy controls in all three spatial directions.
• Specific differences were noted in systolic and diastolic HDF of both the right ventricle (RV) and left ventricle (LV).
• The RV showed augmented transverse forces, while LV abnormalities appeared related to underfilling.

Conclusions:

• Hemodynamic force analysis provides valuable information on pathological cardiac pumping in precapillary pulmonary hypertension, complementing existing parameters.
• The findings suggest the right ventricle compensates for increased afterload via enhanced transverse forces.
• Left ventricular dysfunction in PH_precap may primarily stem from underfilling rather than intrinsic myocardial issues.