Computational quantification of patient-specific changes in ventricular dynamics associated with pulmonary...

Area of Science:

• Cardiovascular Physiology
• Computational Biology
• Medical Imaging

Background:

• Pulmonary arterial hypertension (PAH) imposes increased mechanical load on the right ventricle (RV), leading to functional and mechanical alterations.
• Understanding these RV mechanical changes is crucial for assessing PAH progression and patient outcomes.

Purpose of the Study:

• To quantify mechanical changes in the RV associated with PAH using a computational modeling framework.
• To identify clinical indicators that correlate with underlying mechanical remodeling in PAH patients.

Main Methods:

• Assimilation of clinical data, including 3D geometry, pressure, volume waveforms, and regional strains from PAH patients (n=12) and controls (n=6).
• Optimization of computational models to match patient measurements, focusing on regional passive stiffness and load-independent contractility.
• Comparison of optimized modeling parameters with clinical metrics to identify predictive indicators.

Main Results:

• Peak contractility of the RV free wall (RVFW) showed a strong inverse correlation with the RV end-diastolic volume to LV end-diastolic volume ratio (RVEDV/LVEDV) (R²=0.77).
• Patients with RVEDV/LVEDV > 1.5 exhibited significantly lower RVFW contractility (25% lower, P < 0.05) compared to controls.
• Progressive increase in RVFW passive stiffness was observed with increasing RVEDV/LVEDV, indicating worsening remodeling.

Conclusions:

• The RVEDV/LVEDV ratio serves as a valuable clinical index for assessing RV free wall contractility and disease severity in PAH.
• This study provides a mechanical basis for using RVEDV/LVEDV in clinical practice for PAH management.
• Patient-specific data assimilation and computational modeling offer insights into the physical description of clinical observations in PAH.