Increased DPG predicts mortality in pulmonary hypertension
medwireNews: The risk for death increases with increasing diastolic pulmonary gradient (DPG) in patients with World Health Organization (WHO) group 1 pulmonary hypertension (PH), American research suggests.
After accounting for the Pulmonary Hypertension Connection (PHC) risk equation and pulmonary artery systolic pressure, mortality risk increased by 33% with every 10 mmHg increase in DPG, Sula Mazimba (University of Virginia Health System, Charlottesville) and colleagues report in Respiratory Medicine.
They say: “These findings support the use of the DPG as an important hemodynamic variable in the risk stratification of patients with WHO group 1 PH.”
The mean DPG, calculated as the difference between pulmonary artery diastolic pressure and mean pulmonary capillary wedge pressure, was 31.6 mmHg in the 225 National Institutes of Health Primary Pulmonary Hypertension registry patients included in the study.
But the researchers note that DPG distribution was broad compared with that typically observed in heart failure, which is characterized by a median DPG below 10 mmHg and a cutoff value of 7 mmHg. Only 1.8% of patients had a value below that cutoff in this cohort.
When the researchers grouped the patients by DPG quartiles, they found that those in the highest quartile (DPG >40 mmHg) had a 2.12-fold higher risk for death during the 5-year follow-up period than those in lower quartiles after adjustment for the PHC equation and diastolic pulmonary pressure (p=0.01).
The 40 mmHg cutoff also conferred the greatest specificity for survival, at 82%, but the associated sensitivity was only 31%. The optimal cutoff for sensitivity and specificity was the median DPG value of 30 mmHg, where both values were just over 60%.
Mazimba and colleagues note that a DPG measurement above 7 mmHg is already associated with the presence of pulmonary vascular disease and increased adverse outcomes in PH secondary to left heart disease.
Their current findings suggest assessing that “a DPG threshold of greater than 30 mmHg in group 1 PH patients may provide a parallel means of risk stratification for these patients,” they write.
The researchers add: “This has important clinical implications in extending the application of DPG to patients with group 1 PH.”
They conclude: “Further studies are needed to evaluate the clinical applicability of this hemodynamic variable in the more contemporary era of pulmonary vasodilator therapies.”
By Laura Cowen
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