Assessment of Pulmonary Perfusion and Hemodynamic Measurements by Electrical Impedance Tomography in Patients Undergoing Pulmonary Thromboendarterectomy.

Assessment of Pulmonary Perfusion and Hemodynamic Measurements by Electrical Impedance Tomography in Patients Undergoing Pulmonary Thromboendarterectomy.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a condition in which old blood clots block the blood vessels in the lungs, making it harder for the heart to pump blood through the lungs. Surgery called pulmonary thromboendarterectomy can remove these clots and improve blood flow, but doctors need reliable ways to evaluate lung blood flow before and after surgery.

This study will evaluate a bedside imaging method called electrical impedance tomography (EIT), which can measure how blood flows through different regions of the lungs without radiation or invasive procedures. Patients undergoing surgery for CTEPH will be monitored with EIT before and after surgery, and the results will be compared with standard lung perfusion imaging.

The goal of this study is to determine whether EIT can provide useful information about lung blood flow and changes after surgery, and whether it could serve as a complementary bedside tool to help monitor patients with CTEPH.

Chronic thromboembolic pulmonary hypertension (CTEPH) results from persistent obstruction of the pulmonary arteries by organized thromboembolic material and is a potentially curable cause of pulmonary hypertension. Pulmonary thromboendarterectomy is the treatment of choice for eligible patients and leads to significant improvement in pulmonary perfusion and hemodynamics.

Assessment of regional pulmonary perfusion is essential in the management of CTEPH. While perfusion SPECT/CT is commonly used for this purpose, it cannot be performed at the bedside and involves exposure to ionizing radiation. Electrical impedance tomography (EIT) is a non-invasive, radiation-free imaging technique that allows bedside assessment of lung ventilation and pulmonary perfusion through analysis of pulsatility-related impedance changes.

In this prospective diagnostic study, pulmonary perfusion assessed by EIT will be evaluated in patients undergoing pulmonary thromboendarterectomy and compared with perfusion SPECT/CT. EIT measurements will be obtained in the perioperative period, and perfusion changes will be analyzed using quantitative indices derived from impedance signals. The study focuses on the feasibility and performance of EIT as a bedside method for assessing pulmonary perfusion changes associated with surgical treatment of CTEPH.

Inclusion Criteria:

- Patients diagnosed with chronic thromboembolic pulmonary hypertension (CTEPH) followed at the Pulmonology Service of InCor-HCFMUSP and scheduled for pulmonary thromboendarterectomy at InCor-FMUSP.

Exclusion Criteria:

• Age under 18 years
• Pregnancy
• Structural heart disease (atrial septal defect, ventricular septal defect, or valvular heart disease)
• Cardiac arrhythmias
• Use of a cardiac pacemaker or other implantable electronic device
• Skin lesions on the thoracic region at the site of EIT electrode belt placement
• Absence of central venous access on the day of the preoperative protocol evaluation
• Difficulty understanding the procedures to be performed
• Refusal to participate in the study (non-signing of the Informed Consent Form)
• Refusal by the attending medical team