Balloon pulmonary angioplasty reduces sleep apnea in chronic thromboembolic pulmonary hypertension (CTEPH) patients, according to a study. The observed improvements further correlated with a better mean pulmonary arterial pressure.
The results from the study, “Balloon pulmonary angioplasty attenuates sleep apnea in patients with chronic thromboembolic pulmonary hypertension,” was published in the journal Heart & Lung.
Sleep apnea, a disorder characterized by repeated breathing stops during sleep, is prevalent among patients with pulmonary hypertension (PH), including those with CTEPH.
Studies have shown a relationship between hemodynamics (the dynamics of blood flow) and sleep apnea in patients with PH. Consequently, it is plausible that mechanisms linked to hemodynamics could affect sleep, and that improvements in hemodynamics could reduce sleep apnea in these patients.
Balloon pulmonary angioplasty (BPA) — a technique that restores blood flow by opening narrowed or blocked lung arteries with a balloon — is one method that can be used to improve hemodynamics in CTEPH patients. However, no direct associations have been reported between BPA and sleep-associated breathing problems.
In the study, researchers evaluated the effect of BPA on sleep apnea in CTEPH patients, and assessed the specific BPA-induced hemodynamic changes that could explain a potential improvement.
The study enrolled 13 patients with CTEPH and sleep apnea (median age of 57 years) undergoing BPA. Patients were assessed through electrocardiogram (to assess the electrical function of the heart), chest and abdominal respiratory effort, nasal airflow, and hemoglobin saturation in the artery, both before BPA and six months after the last BPA session.
Clinicians assessed the apnea-hypopnea index (AHI) — measuring the severity of sleep apnea, based on the number of sleep disruptions and abnormal breathing events per hour of sleep — before BPA and six months after the procedure. All included patients had AHI scores above 10, indicating at least mild sleep apnea.
The team found decreased levels of parameters associated with blood pressure in the patients six months after they had undergone BPA. These parameters include pulmonary vascular resistance, mean right arterial pressure, and mean pulmonary arterial pressure (mPAP). BPA also lowered levels of brain natriuretic peptide, a hormonal indicator of heart failure. In addition, the patients showed an increase in blood gas oxygen saturation (SaO2) at rest, from 89.8 to 95.5%, and in six-minute walk distance (a test assessing exercise capacity) from a median of 358 meters to 500 meters.
The patients undergoing BPA also showed an improvement in the World Health Organization functional classification, which classifies patients into four different illness levels (the higher the class, the worse the patient’s condition). Patient distribution within the four categories went from predominantly belonging to Class III (11 patients; no patients in Class I) to mostly belonging to Class I (seven patients; no patients in Class III).
When the researchers assessed apnea-associated parameters six months after BPA, they found a significant decrease in AHI (from a median of 20.9 to 16.3 events per hour), as well as total sleep time with less than 90% SaO2 (from a median of 74.8% to 11.9%).
They further found that the improvements in AHI correlated significantly with mPAP changes, but not with other measured factors. According to the investigators, this correlation supports a link between sleep apnea and hemodynamics.
Still, the researchers highlighted that the relationship between PH and sleep apnea could be bidirectional. In other words, apnea-induced hypoxemia (low levels of oxygen in the blood) and reduced oxygen saturation during the night may indirectly contribute to PH worsening, as well as the other way around.
Overall, the study showed that BPA could reduce the severity of sleep apnea in patients with CTEPH, and therefore the team suggested that “close attention should be paid to [sleep apnea] in CTEPH patients,” and that it “should be re-evaluated after BPA to avoid overestimating its severity.”