Thoracic Bio-reactance Measurement of Cardiac Output in Pulmonary Hypertension

Interest of Cardiac Output Measurement by Thoracic Bio-reactance for Monitoring of Patients Treated for a Pulmonary Hypertension

Pulmonary Hypertension (PH) is a rare disease characterized by an increase in pulmonary vascular resistance, leading to a progressive decline in cardiac output (CO).Since cardiac output is correlated with the prognosis of the disease, the conduct of a right heart catheterization (thermodilution measurement, reference technique) during the annual follow-up visit of patients in competences centres is recommended. In practice, it is not systematically performed because of it is invasive, with potential risk for the patient, and there is limited logistical capacity for its implementation. The estimation of cardiac output is thus often based on cardiac ultrasound but its measurement is potentially biased.

Starling ™ SV is a non-invasive cardiac output monitor based on thoracic bio-reactance measurement. Several clinical studies have shown that cardiac output measured by bio-reactance is strongly correlated with the measurement obtained by catheterization in different indications. Rich et al. (2013) assessed bio-reactance specifically in 50 patients with Pulmonary Hypertension compared with thermodilution. The results showed that the measurement of cardiac output by bio-reactance was feasible in these patients, had a better accuracy than by catheterization, and was reliable for detecting changes in cardiac output after a vasodilatation test.

The Starling ™ SV monitor could thus have a place in the follow-up of patients who are being treated for Pulmonary Hypertension. Since it is a rapid, non-invasive examination, it could be performed on an outpatient basis, especially as a first-line test to check the stability of the CO, thus avoiding the systematic use of right heart catheterization, which would then be reserved only to patients for whom the measurement by bio-reactance would show a decrease of cardiac output compared to the previous value. Before being able to propose this use in current practice, it is necessary to carry out a pilot study which will make it possible to explore the interest of bio-reactance in this situation.

Inclusion Criteria:

• Aged over 18
• Presenting pulmonary hypertension (PH) followed by the Competence Center of the Hospices Civils de Lyon
• Follow-up for pulmonary hypertension groups 1, 4 or 5
• Of which the cardiac index is ≥ 2,5 L/min/m²
• Expressing its non-opposition to the participation of this study
• Benefiting from a social security scheme or similar

Exclusion Criteria:

• Adult patient protected by Law
• Patient for whom a thermodilution measurement of cardiac output (CO) is unreliable: right-left shunt; or uncorrected congenital heart disease; or variability> 10% of the 3 measurements of CO obtained by thermodilution
• pulmonary hypertension groups 2 or 3
• Hemodynamic aggravation since the previous visit: increased pressure or decreased cardiac index