Clinical Utility Of Noninvasive Assessment Of Flow-Pressure Relationship In Scleroderma

Introduction: Cardiac involvement in Systemic sclerosis (SSc), especially left ventricular diastolic dysfunction (DD), is high prevalence and associated with high mortality. Thus, the early detection of left ventricular DD might be important to manage SSc. Recent study has shown that exercise stress test may evaluate an early stage of heart failure in patients with normal resting echocardiogram. Hypothesis: We hypothesized that SSc patients with normal resting hemodynamics may present early phase of left ventricular DD by exercise echocardiogram, leading to the model of predicting long-term outcomes. Methods: Between January 2014 and December 2018, we prospectively enrolled 140 SSc patients who underwent 6-minute walk (6MW) stress echocardiographic studies with normal range of estimated mean pulmonary arterial pressure (mPAP) (<25mmHg) and mean pulmonary artery wedge pressure (mPAWP) (<15mmHg) at rest. We used ΔmPAP/Δcardiac output (CO) to assess pulmonary vascular reserve and ΔmPAWP/ΔCO to assess left ventricular (LV) reserve between resting and post-6MW point. Results: During a median period of 3.6 years, 25 patients (18%) reached the composite outcome. Both ΔmPAP/ΔCO and ΔmPAWP/ΔCO in patients with events were significantly higher than in ones without events (8.9±3.8mmHg/l/min vs. 3.0±1.7mmHg/l/min; p=0.002, and 2.2±0.9mmHg/l/min vs. 0.9±0.5mmHg/l/min; p<0.001, respectively). In addition, ΔmPAWP/ΔCO is strongly associated with events (p=0.04) in patients with normal ΔmPAP/ΔCO (≤median value), although ΔmPAWP/ΔCO had weak impact in patients with abnormal ΔmPAP/ΔCO (>median value) (p=0.23). Conclusions: Exercise echocardiography revealed impaired LV functional reserve in SSc patients with normal resting hemodynamics. Furthermore, in the group of normal pulmonary vascular function, the patients with impaired LV functional reserve had significantly shorter event-free survival than the ones with non-impaired LV function. Thus, the evaluation of early left ventricular DD with 6MW may detect high-risk group in SSc patients.