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A3711 - Morphing Physiology: A Case of Occult Systemic Sclerosis Sine Scleroderma Associated Pulmonary Hypertension
Author Block: N. Ruopp1, H. W. Farber2; 1Pulmonary/Critical Care, Boston, MA, United States, 2Boston Univ Sch of Med, Boston, MA, United States.
Introduction: Systemic sclerosis sine scleroderma (ssSSc) is diagnostically challenging owing to its protean nature. The prevalence of pulmonary arterial hypertension (PAH) in ssSSc is approximately 22-23%, with the occurrence of PAH without other lung involvement rarer still. World Health Organization (WHO) Group 2 pulmonary hypertension (PH) associated with ssSSc has not been described. We present a case of occult ssSSc with variable cardiopulmonary physiology- initially manifesting as Group 2 PH with subsequent resolution and development of rapidly progressive Group 1 PAH. Case: A 63yo female with Raynauds phenomenon and numerous risk factors for diastolic dysfunction presented with worsening dyspnea on exertion and edema. She had been previously diagnosed 2 years prior with WHO Group 2 PH by right heart catheterization (RHC) (pulmonary artery wedge pressure 27mmHg; PAWP) and had since been maintained on an aggressive diuretic regimen with marked clinical improvement despite no other lifestyle modifications. Exam was consistent with RV dysfunction and transthoracic echocardiogram (TTE) was notable for a dilated right atrium (RA) and right ventricle (RV) pressure and volume overload with normal left sided systolic function. Repeat RHC showed mean RA pressure 12mmHg, mean pulmonary artery pressure 52mmHg, normal PAWP even following volume challenge, pulmonary vascular resistance 11.2 Wood units, and cardiac index 2.10 L/min/m2 consistent with severe PAH without evidence of left sided disease. She was initiated on epoprostenol because of rapidly progressive symptoms (Functional Class 3b-4) with excellent hemodynamic response and no increase in PAWP. Subsequent evaluation revealed nucleolar ANA 1:640 with all other auto-antibodies negative. Computed tomography (CT) scan of the chest showed no interstitial lung disease, and she was ultimately diagnosed with ssSSc and, thus, ssSSc-PAH. The mechanism by which the physiology “morphed” from established Group 2 PH to rapidly progressive Group 1 PAH is unknown and unclear. However, we surmise that the previous diastolic dysfunction could have represented an early, occult manifestation of ssSSc. Discussion: Resolution of Group 2 PH in ssSSc has not been reported and the mechanism of change in this patient remains unclear. On autopsy cardiac involvement in ssSSc is secondary to fibrosis that would have been unlikely to resolve. Occult myocarditis or pericarditis secondary to ssSSc that resolved spontaneously is possible, but there was no evidence of either. Small vessel ischemic disease occurs scleroderma, but seems unlikely. In sum, the evolution of Group 2 PH to Group 1 PAH in ssSSc is a novel occurrence not been previously reported.