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

University of Sao Paulo General Hospital36 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

Interventions

Electrical Impedance Tomography (EIT).DIAGNOSTIC_TEST

Non-invasive, radiation-free bedside assessment of pulmonary perfusion using Electrical Impedance Tomography (EIT). EIT will be performed using the Enlight 2100 system (Timpel Medical®, Brazil) in the preoperative and postoperative periods of pulmonary thromboendarterectomy. Pulmonary perfusion will be assessed through analysis of pulsatility signals and first-pass kinetics following hypertonic saline bolus injection, generating regional perfusion maps and quantitative indices, including the wasted ventilatory index. Data will be analyzed offline.

Pulmonary Perfusion SPECT-CT.DIAGNOSTIC_TEST

Pulmonary perfusion assessment performed using single-photon emission computed tomography (SPECT) with technetium-99m-labeled macroaggregated albumin, fused with non-contrast chest computed tomography (CT) acquired during both inspiratory and expiratory phases. The fusion of functional perfusion images from SPECT with anatomical images from CT allows regional assessment of pulmonary perfusion and thromboembolic burden. This examination will be performed in the preoperative period and during postoperative follow-up and will serve as a reference imaging modality for comparison with Electrical Impedance Tomography-derived perfusion measures.

Pulmonary Thromboendarterectomy.PROCEDURE

Pulmonary thromboendarterectomy performed according to standard institutional clinical practice for the treatment of chronic thromboembolic pulmonary hypertension. This surgical procedure is conducted solely for clinical indication and is not investigational. Imaging and monitoring assessments included in this study do not alter the surgical technique or perioperative clinical management.

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

Evaluation of perfusion maps obtained by Electrical Impedance Tomography (EIT) in the pre- and postoperative period using the wasted ventilation index..

Change in pulmonary perfusion assessed by Electrical Impedance Tomography (EIT) using the Enlight 2100 system (Timpel Medical®, Brazil), quantified by the wasted ventilatory index derived from regional perfusion maps, comparing preoperative and postoperative measurements in patients undergoing pulmonary thromboendarterectomy.

Time frame: From the preoperative period to the immediate postoperative period during intensive care unit stay (on the day of surgery).

Secondary Outcomes

Comparison of pulmonary perfusion assessed by Electrical Impedance Tomography and SPECT-CT.

Comparison of changes in regional pulmonary perfusion assessed by Electrical Impedance Tomography (EIT) and by SPECT-CT imaging, expressed as percentage variation between preoperative and postoperative evaluations in patients undergoing pulmonary thromboendarterectomy.

Time frame: From the preoperative period to the postoperative follow-up (up to 6 months after surgery).

Incidence of adverse events related to Electrical Impedance Tomography perfusion assessment.

Incidence and type of adverse events related to pulmonary perfusion assessment using Electrical Impedance Tomography, including events associated with the use of hypertonic saline injection.

Time frame: From the preoperative period to hospital discharge, up to approximately 30 days