Measures of pulmonary arterial capacitance (PAC) may help to predict the risk of heart problems in patients with pulmonary hypertension caused by left heart disease. But before the method might be applied in the clinic, studies are needed to confirm its usefulness.
The study, “Pulmonary Arterial Capacitance Predicts Cardiac Events in Pulmonary Hypertension Due to Left Heart Disease,” was published in the journal PLOS ONE.
Lung hypertension caused by left heart disease is a very common form of pulmonary hypertension, but little is known about factors that contribute to the disease.
PAC is a measure of the ratio between volume and pressure in the right ventricle of the heart as blood is leaving it. Studies have also shown that the measure can be used to set a prognosis in patients with heart failure. Researchers at Fukushima Medical University, for this reason, analyzed if the measure can also be used to assess disease course in patients with lung hypertension caused by left heart disease.
The research team recruited 252 patients, including 145 men. All had been diagnosed with pulmonary hypertension through right heart catheterization. Researchers divided the patients into four groups based on their PAC values, and then followed them to see how their disease developed over time.
Patients were followed for a median of 943 days. The study showed that the lower the PAC measure, the higher was the pulmonary vascular resistance. This was mirrored by the fact that patients in the group with the lowest PAC values had more severe heart disease. The use of drugs for heart failure was also more widespread in this group.
Several measures of lung hypertension, such as the mean pulmonary artery pressure, were also higher in this group compared to patients in groups with higher PAC values.
Analyses showed that those with the lowest PAC measures had the highest rates of heart problems during the study, as determined by the rate of survival without heart problems.
Event-free survival was also predicted by the severity of heart disease, as measured by high levels of B-type natriuretic peptide, and low levels of estimated kidney glomerular filtration rate and hemoglobin.
“In the present study, we showed the importance of PAC when predicting cardiac event risk in LHD-PH [pulmonary hypertension due to left heart disease] patients. PAC should also be considered as an important contributing factor of right ventricular afterload,” the team concluded. “Further multicenter studies are required in future to fully validate these findings.”