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Myositis-Related Autoantibodies and Pulmonary Arterial Hypertension (PAH): Another Sub-Type of PAH Associated with Autoimmune Conditions

S Si

Sophia Weinmann

VN Despotovic

Colleen McEvoy

Murali Chakinala

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Conference: 2018 PHA International PH Conference & Scientific Sessions

Release Date: 06.28.2018

Presentation Type: Abstracts

2018 International PH Conference and Scientific SeAbstract presented at the 2018 International PH Conference and Scientific Sessions in Orlando, Fla., June 28-July 1, 2018.

Background

Patients being evaluated for PAH must be screened for underlying (autoimmune) connective tissue diseases (CTD). Available commercial assays identify myositis-related autoantibodies that are associated with autoimmune inflammatory myopathies or myositis overlapping with CTDs. However, little is known regarding the clinical characteristics of these autoimmune conditions with myositis-related autoantibodies and concomitant pulmonary arterial hypertension (PAH) or the implications of such testing on clinical practice.

Methods

In this single-center, retrospective case series, we explored the phenotypic, laboratory, functional, hemodynamic, and treatment profile of 37 patients with PAH (mean PAP ≥ 25, normal LV filling pressures, PVR ≥ 3) and myositis autoantibodies evaluated between August 2012 to January 2017. Myositis autoantibody testing was carried out utilizing the MyoMarker Panel 3 (RDL Reference Laboratory, Inc.).

Results

Median age of the cohort was 61 years (range 30 to 80) and 29 patients (78%) were female. 15 (41%) patients were determined to have two myositis autoantibodies and 3 (8%) patients had three unique myositis autoantibodies. The SSA-52 autoantibody was most common, present in 25 (68%) patients. Detection of myositis autoantibodies aided in either a novel CTD diagnosis or an alternative CTD diagnosis in 11 patients. 6 patients were diagnosed with antisynthetase syndrome. 22 (59%) patients had interstitial lung disease and 29 (78%) patients were NYHA Functional Class III or IV. The cohort’s mean (±SD) (% predicted) FEV1, FVC, and TLC was 64 ± 20%, 71 ± 20%, 77 ± 21%, respectively, while the 6-minute walk distance was 256 ± 128 meters. Mean pulmonary artery pressure (PAP) was 44 ± 11 mmHg and pulmonary vascular resistance (PVR) was 9 ± 4 Wood units, including 29 (78%) patients with mPAP >35 mmHg. At the time of myositis autoantibody positivity, 2 (5%) patients were being treated with a calcium-channel blocker, 11 (30%) with an endothelin receptor antagonist, 28 (76%) with a PDE5 inhibitor, and 10 (27%) with a prostacyclin analogue.

Conclusions

In this novel cohort of myositis autoantibody positive patients diagnosed with PAH, there was a high prevalence of severely elevated mPAPs and PVR. During the evaluation of possible pulmonary arterial hypertension, testing for myositis autoantibodies should be considered and may be informative.

Table 1. Distribution of myositis autoantibodies in 37 patients.
*Antisynthetase antibodies.