Impaired Myocardial Flow Reserve on 82Rubidium Positron Emission Computed Tomography in Patients with Systemic Sclerosis.

OBJECTIVE: To investigate the association between Raynaud phenomenon (RP) and coronary microvascular dysfunction, we measured myocardial flow reserve (MFR) using positron emission tomography/computed tomography (PET/CT) in primary and secondary RP patients and controls. METHODS: RP patients, patient controls and healthy participants who underwent dynamic reststress 82-Rubidium PET/CT were studied. Differences in heart rate-blood pressure product corrected MFR and clinical predictors of reduced MFR (< 2.0) were determined. RESULTS: 49 RP patients (80% female, 65 ± 11 years): 11 primary RP, 18 systemic sclerosis (SSc) and 20 other autoimmune diseases (AID) (n=6 systemic lupus erythematosus, n=6 rheumatoid arthritis, n=4 overlap syndrome, n=2 Sjogren's syndrome, n=2 inflammatory arthritis), 49 matched patients without RP or AID (78% female, 64 ± 13 years) and 14 healthy participants (50% female, 35 ± 5 years) were studied. Primary RP patients, matched patient controls and healthy participants had comparable MFR. SSc-RP patients had significantly reduced MFR (1.62 ± 0.32) compared to matched patient controls (p=0.03, 2.06 ± 0.61) and to healthy participants (p=0.01, 2.22 ± 0.44). In multivariable logistic regression, SSc was an independent predictor of reduced MFR. We identified a correlation between time since AID diagnosis and MFR (r= -0.37; 95% CI: -0.61 to -0.09; p=0.01). CONCLUSION: Our findings suggest that only secondary, not primary, RP is associated with reduced MFR, and that SSc-RP patients have reduced MFR compared to primary RP and other.