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Assessment of Gas Exchange in Patients with Severe Pulmonary Hypertension Related to Pulmonary Fibrosis, Before and During Treatment with Parenteral Prostanoid

Kathy McCloy

A. Derhovanessian

David Ross


Shelley Shapiro


Glenna Traiger


E. Volkmann

N. Williams

L. Yoder

Rajan Saggar


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Conference: 2014 International PHA Conference and Scientific Sessions

Release Date: 06.22.2014

Presentation Type: Abstracts

File Download: 2014 Conference Abstract - Kathy McCloy

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Pulmonary hypertension (PH) may complicate pulmonary fibrosis (PF) [PH-PF]. A major clinical concern with initiating PH-targeted therapy in PH-PF patients has been the potential for ventilation-perfusion (V-Q) mismatch and subsequent hypoxemia.

Background: Pulmonary hypertension (PH) may complicate pulmonary fibrosis (PF) [PH-PF]. A major clinical concern with initiating PH-targeted therapy in PH-PF patients has been the potential for ventilation-perfusion (V-Q) mismatch and subsequent hypoxemia. We have previously shown that PH-targeted therapy may improve right ventricular function without affecting oxygen saturation by pulse oximetry.  This pilot study incorporates arterial blood gas (ABG) testing to comprehensively evaluate gas exchange in PH-PF before and during parenteral prostanoid.

Methods: Severe PH was defined as mPAP ≥35 mm Hg.  Demographics, lung disease clinical subtype and background PH-targeted therapy were collected.  Chest CT scan, pulmonary function tests and echocardiograms were reviewed to characterize lung disease and heart function. Patients were initiated on parenteral prostanoid at 2 ng/kg/min and increased by a maximum of 1-2 ng/kg/min every 72 hours.  We compared 6MWD and ABG parameters on the same oxygen supplementation, before and during parenteral prostanoid initiation. 

Results: 12 patients (58% male) were evaluated with PF etiology [CPFE (4), NSIP-F (3), NSIP (2), UIP-RA (1), IPF (1) and diffuse PF with honeycombing (1)]. Baseline assessments were as follows (median [IQR]): age 65 [58,70]; background PH-targeted therapy (75%); functional class IV (83%); oxygen requirements 3 liters/min [2,8]; [lung function] %FVC  70 [43,87]; %FEV1 62 [43,85]; %DLCO 26 [17,28]; [hemodynamics] mPAP 50 [45,55], PVR 7.8 [6.8,12.2], CI 2.2 [1.7,2.7]; PAWP 11 [10,14]; and [echocardiography] RVSP 81 [69,100]; TAPSE 1.5 [1.4,2.4]; LAV-BSA 13.8 [11,19.4]; LVEF 60% [55,60]. The current status of patients is as follows: deceased (2), lung transplant (3), alive and not transplant candidates (7).  The follow-up period was 5-10 weeks; parenteral prostanoid dose was 17 ng/kg/min [11,24]. The analysis of 6MWD, ABG and BNP before and during parenteral prostanoid initiation is outlined in the table below:

Variable Change (Median, [IQR]) p-value (Wilcoxon)
6MWD 78 meters [30,81] 0.004
pCO2 1 mmHg [-7,1] 0.11
pO2 3 mmHg [-13, 8] 0.75
SaO2 0.2 mm Hg [-2.4,3.1] 0.76
BNP -219 pg/ml [538, -5] 0.11

Conclusions: Parenteral prostanoid may be beneficial in the setting of severe PH related to PF and in general, gas exchange remains preserved. In this pilot study, parenteral prostanoid therapy did not result in predictable worsening of hypoxemia in patients with PF complicated by severe PH.

Type: Clinical Science