BOLD-SSc – 5-Year OS-CMR Follow-Up of Early Heart Involvement in Systemic Sclerosis

Assessment of Subclinical Right Ventricular Dysfunction in Systemic Sclerosis using OS-CMR (Oxygen-Sensitive Cardiac Magnetic Resonance) and Strain Echocardiography — 5-Year Follow-Up

Systemic sclerosis (SSc) is an autoimmune disorder in which excess collagen deposition causes fibrosis and hardening of tissues throughout the body, including the heart. Right ventricular (RV) failure is the leading cause of death in SSc, driven by both pulmonary hypertension and primary myocardial involvement from microvascular ischaemia and fibrosis. RV dysfunction typically remains silent until advanced, and current tools such as echocardiography are not sensitive enough to detect it at an early, potentially treatable stage.

The BOLD-SSc trial uses OS-CMR (oxygen-sensitive cardiac magnetic resonance, formerly referred to as BOLD — blood oxygen level dependent — cardiac MRI), alongside parametric T1 mapping, 4D flow imaging, and echocardiography speckle tracking, to detect early ischaemic and fibrotic changes in the RV of SSc patients before overt dysfunction or pulmonary hypertension develops. At baseline, the study recruited a prospective case-control cohort of 23 SSc patients, 17 age- and gender-matched healthy volunteers, and 10 patients with confirmed pulmonary arterial hypertension (PAH) as a comparator group, with a subset undergoing additional 4D flow imaging.

CIRSA's current focus is the study's 5-year follow-up phase: of the 23 SSc patients enrolled at baseline, 12 have returned for follow-up assessment, which includes repeat OS-CMR and assessment of major adverse cardiac events (MACE), to determine whether the early imaging markers identified at baseline — RV myocardial deoxygenation under stress, strain abnormalities, and fibrotic changes — predict which patients go on to develop overt RV dysfunction or pulmonary hypertension over time.