According to one study, breathing problems are more common in heart failure patients with reduced ejection fraction who also have pulmonary hypertension (PH) than in those who do not.
Patients with PH also had poorer lung function and long-term survival than those without PH. However, while spirometry can be used to estimate long-term survival in people without PH, it cannot make reliable estimates for patients with PH, regardless of how well their lungs function, noted L. ‘Research Team. Spirometry, a measurement of the amount of air flowing in and out during a single breath, is a test of lung health.
“The presence of PH interacts with lung function results and makes spirometry [lung function] ineffective indices to provide prognostic information on long-term outcomes in heart failure patients with reduced ejection fraction,” the researchers wrote.
The study, “Prognostic role of lung function in heart failure patients with reduced ejection fractionwas published in the Journal of the American Heart Association.
Ejection fraction is a measure of the heart’s ability to pump blood from the ventricles – the two downward chambers of the heart – to the body. It is usually expressed as a percentage: a normal ejection fraction can be 50% to 75%, and a borderline ejection fraction from 41% to 49%. An ejection fraction of 40% or less means the heart’s ability to pump blood with each heartbeat is impaired.
A low ejection fraction can cause high pressure in the left ventricle – the heart’s main pumping chamber – as blood fills it between each heartbeat. In turn, this can lead to breathing problems and PH, or high pressure in the blood vessels of the lungs. An estimated 40% to 75% of heart failure patients with reduced ejection fraction develop PH.
“Although it has been reported that the presence of PH can also affect lung function, the correlation between ventilatory abnormalities and the presence of PH attributable to left heart disease has [not] yet been well studied,” the researchers wrote.
To better determine if there is a correlation, the researchers relied on data from INHALER (INvestigate HeArt and Lung intERaction), a registry at a major medical center in Taiwan.
They included 440 patients (mean age, 66.2; 77% male) with an ejection fraction measured at the left ventricle of 40% or less. All patients underwent echocardiography – a procedure that uses ultrasound to see how well the heart is pumping blood – and spirometry.
Of these 440 people, 158 (35.9%) patients had a PH, defined as a pressure against the wall of the pulmonary artery of 50 millimeters of mercury (mmHg) or more. The pulmonary artery is the large blood vessel carrying blood from the right ventricle of the heart to the lungs.
Compared to patients without HP, those with HP had significantly lower total lung capacity (78.3% vs. 83.8%), forced vital capacity (62.6% vs. 70.5%), and forced expiratory volume in the first second (63.9% against 72.4%). %). All three spirometry tests are measurements of lung function.
During a median follow-up of about two years (25.9 months), 111 of these people died. Compared to patients without HP, those with HP had a higher mortality risk (33.5% versus 20.6%). Deaths due to cardiovascular causes were identified in 32 (55.2%) patients without HP and 34 (64.2%) with HP.
After accounting for multiple factors, total lung capacity, forced vital capacity, and forced expiratory volume in the first second were all correlated with mortality in patients without HP. Impaired lung function linked to 2.85 times higher risk of death for patients without PH, but not for those with PH.
“Lung function provided prognostic information for long-term survival in patients without PH, but not in patients with PH, regardless of functional ability. The study suggested that spirometric variables could be sensitive markers to reflect cardiopulmonary interaction in HF [heart failure]; however, meaningful prognostic information could only be limited to patients without PH,” the researchers wrote.
“Despite the fact that static spirometric measurement is not associated with long-term outcomes in the presence of PH, whether exercise capacity is a more reliable prognostic factor requires further investigation,” they said. they added.