Pulmonary Vasospasm in Systemic Sclerosis: Noninvasive Techniques for Detection

Abstract

In a subgroup of patients with systemic sclerosis (SSc), vasospasm affecting the pulmonary circulation may contribute to worsening respiratory symptoms, including dyspnea. Noninvasive assessment of pulmonary blood flow (PBF), utilizing inert-gas rebreathing (IGR) and dual-energy computed-tomography pulmonary angiography (DE-CTPA), may be useful for identifying pulmonary vasospasm. Thirty-one participants (22 SSc patients and 9 healthy volunteers) underwent PBF assessment with IGR and DE-CTPA at baseline and after provocation with a cold-air inhalation challenge (CACh). Before the study investigations, participants were assigned to subgroups: group A included SSc patients who reported increased breathlessness after exposure to cold air (n = 11), group B included SSc patients without cold-air sensitivity (n = 11), and group C patients included the healthy volunteers. Median change in PBF from baseline was compared between groups A, B, and C after CACh. Compared with groups B and C, in group A there was a significant decline in median PBF from baseline at 10 minutes (−10%; range: −52.2% to 4.0%; P < 0.01), 20 minutes (−17.4%; −27.9% to 0.0%; P < 0.01), and 30 minutes (−8.5%; −34.4% to 2.0%; P < 0.01) after CACh. There was no significant difference in median PBF change between groups B or C at any time point and no change in pulmonary perfusion on DE-CTPA. Reduction in pulmonary blood flow following CACh suggests that pulmonary vasospasm may be present in a subgroup of patients with SSc and may contribute to worsening dyspnea on exposure to cold.

The effect of cold stress on right ventricular function in patients with systemic sclerosis

“…Mukerjee et al, evaluated right ventricular function using cardiac catheterization after 2 minutes of cold stress, and found no differences whereas Sakamoto et al, found an increase in pulmonary hypertension in a subgroup of patients [11,8]. In a recently published study, Keir et al, implied pulmonary vasospasm as a possible explanation to worsening symptoms in a subgroup of patients after exposure to cold [6].…”

“…Raynaud's phenomenon is the most common and cardinal feature of SSc seen in about 90% of patients [5]. It is speculated that, the increased vasospastic response as in Raynaud's phenomenon, can also be seen in pulmonary circulation and can be one of the contributing factors in the development of pulmonary hypertension [6][7][8].…”