Atypical pulmonary arterial hypertension in the setting of an elevated diastolic gradient-a subgroup that benefits from treatment.

Document Type

Conference Proceeding

Publication Date


Publication Title

Am J Respir Crit Care Med


Pulmonary hypertension (PH) is characterized by resting mean pulmonary artery pressure (mPAP) of ≥25mmHg. Pulmonary arterial hypertension (PAH) further describes elevated pulmonary vascular resistance (PVR) in the setting of normal pulmonary arterial wedge pressure (PAWP) ≤15mmHg. This is the hemodynamic profile that describes those with idiopathic pulmonary arterial hypertension (IPAH). There is a subgroup of patients that have a hemodynamic profile consistent with PAH, but also have systemic hypertension, obesity, diabetes, and atrial fibrillation. To better study this population, who had previously been either underrepresented or excluded from clinical trials, the term atypical PAH has been proposed. We sought to study outcomes in patients with atypical PAH with elevated diastolic gradient who were treated with vasodilator therapy. Methods We performed a retrospective chart review of 17 patients who met diagnostic criteria for atypical PAH. Our inclusion criteria included patients with a (mPAP) of ≥25mmHg, a PAWP <15 mmHg, and a PVR exceeding 3 wood units. Included patients had three or more of the associated comorbidities including systemic hypertension, obesity, diabetes, and atrial fibrillation. Exclusion criteria included patients with typical PAH, patient with an FVC less than 70% of predicted, or confirmed CTEPH. Endpoints that were investigated in the study include functional class, 6 minute walk test (6MW), mPAP, Tricuspid Annular Plane Systolic Excursion (TAPSE), BORG dyspnea and fatigue scores, and right ventricular morphology and function on echocardiogram at 3 month and 6 month after initiation of vasodilator therapy. A paired 2-test analysis was used to compare difference between the two groups. Results Seventeen patients were identified in our institution that met our inclusion criteria of atypical PAH on vasodilator therapy. Our patient population had an average mPAP of 38mmHg, wedge of 14.7mmHg, Cardiac output/index of 3.9/1.9 and a DPG of 9. The mean ejection fraction was 58%. There was a significant improvement in 6MW by 50.5m (CI=9.8m- 91.2m, p-value=0.02). The functional class decreased by 1.2 with a p-value of 0.001) and the BORG dyspnea score improved by 1.64 (CI=0.15-3.1, p-value=0.03). There was no significant improvement in TASPE, mPAP and BORG fatigue scale. Most of the patients (76%) were on phosphodiesterase type 5 inhibitors. Conclusion There is a lack of evidence in treating patients with atypical IPAH. Our study provides evidence that treating this group of patients with vasodilator therapy can improve outcomes. Further randomized control trials are required to further establish our findings.



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