Patients with mild pulmonary hypertension (PH), with a mean pulmonary arterial pressure between 19 and 21 mmHg, are at significant risk of death, indicating a need for adjustment of the mPAP diagnostic value.
The study, “Mild Pulmonary Hypertension Is Associated with Increased Mortality: A Systematic Review and Meta-Analysis,” was published in the Journal of The American Heart Association.
PH is a chronic lung condition defined by a mean pulmonary arterial pressure (mPAP) greater than 25 mmHg. However, several studies have reported a higher clinical risk of PH development and death in patients with a mean mPAP at or above 19 mmHg, which is considered borderline PH.
Now, researchers re-evaluated published data to investigate the relationship between mildly elevated mPAP and mortality, with the goal of updating the definition of PH by lowering the mPAP threshold and therefore helping improve diagnosis.
Using research databases, the team looked for published studies that discussed mortality in patients with mild PH — mPAP values near but less than 25 mmHg — and compared them to a control group.
They identified 15 studies between the date of database inception and January 2018, with a combined total of 16,482 patients (median age range of 41 to 77 years) and 9,031 controls. The mean duration of follow-up was 5.2 years.
Of the total population, measured or calculated mPAP data was available for 7,451 patients (45.2% of the cohort analyzed). mPAP values were obtained by right heart catheterization (in 6,037 patients) or echocardiography (in 1,414 patients), the two conventional methods of mPAP estimation.
Researchers used statistical analysis to calculate the risk of death in patients with mild PH compared with those in the control group. The mPAP level for the control group across the studies was within 18.5 to 21 mmHg.
Statistical analysis revealed that patients with mild PH had 1.52 times the risk of death compared with the control group.
The time to mortality from the time of mPAP estimation is called time-to-event. This adds a statistical prejudice in determination of the risk. Researchers therefore performed a secondary analysis adjusting for this bias, and found that the results did not change significantly — the secondary analysis showed that the risk of mortality in patients with mild PH was 1.19 times higher compared to the control group.
The results were statistically similar in patients diagnosed through right heart catheterization or by echocardiography, the team noted. Based on the results, the team concluded that “the risk of mortality is increased in patients with mild PH, defined as measured or calculated mean pulmonary artery pressure higher than 19 mm Hg.”
The researchers suggest that the data “support efforts to update the current definition of PH and affirm the reproducibility of mean pulmonary artery pressure greater than 19 mm Hg as an appropriate and clinically accessible level distinguishing patients with PH from patients without PH,” they wrote.
According to the team, by defining a PH diagnosis based on mPAP levels greater than 19 mmHg, it would help “identify previously undiagnosed patients with PH and provide a framework in clinical practice by which to initiate careful monitoring and efforts to modify risk factors and improve outcomes.”