Low Cardiac Index Seen to Predict Sleep Disordered Breathing in CTEPH Patients

People with chronic thromboembolic pulmonary hypertension (CTEPH) show an increased prevalence of sleep disordered breathing, a condition predicted by low cardiac index, according to the study “Usefulness of Low Cardiac Index to Predict Sleep-Disordered Breathing in Chronic Thromboembolic Pulmonary Hypertension,” published in the American Journal of Cardiology.

CTEPH patients are burdened with chronic blood clots and remodeling of the pulmonary vasculature, leading to pulmonary hypertension associated with variable degrees of right ventricular dysfunction.

Patients with left-sided heart failure frequently present sleep disordered breathing, a term comprising conditions characterized by partial or complete cessation of breathing several times throughout the night (increased left heart pressures was previously suggested as the underlying cause of sleep disordered breathing in these patients).

While people with CTEPH usually lack elevated left-sided cardiac pressures, they may have impaired cardiac flux, which can predispose them to sleep disordered breathing. However, its prevalence in CTEPH patients is largely unknown.

Reseachers tackled the link between sleep disordered breathing and CTEPH, recruiting patients referred for evaluation for pulmonary thromboendarterectomy surgery (a procedure to remove blood clots from arteries in the lungs). The participants underwent a sleeping test with a nasal pressure sensor, respiratory effort band, and a pulse oximeter placed on a finger.

In total, 49 patients were included in the study, which measured the results right-sided cardiac catheterization (a standard clinical evaluation in this case).

Sleep disordered breathing, defined as ongoing positive airway pressure use or an apnea-hypopnea index of at least 5 h, was found in 57 percent of all patients analyzed. Cardiac index (a hemodynamic parameter measuring how much blood is being pumped by the heart) was significantly lower in patients with sleep disordered breathing when compared to controls (those without the disorder). Most importantly, the team observed that the cardiac index is a strong predictor of the presence and severity of sleep disordered breathing.

In conclusion, the results suggested that sleep disordered breathing prevalence is higher in patients with CTEPH when compared to the general population. Additionally, treatments that improve cardiac index may significantly improve the disorder in these patients.