Stroke Volume Reserve Is an Independent Predictor of Survival and Need for Advanced Therapies in Systolic Heart Failure Patients

Background Current predictors of clinical deterioration in patients with heart-failure with reduced ejection fraction (HFrEF) have limited accuracy. We investigated whether stroke volume reserve index (SVRI) would predict 1-year mortality and need for advanced therapies in HFrEF patients. Methods We retrospectively studied a consecutive series of 104 ambulatory HFrEF patients (59±11 years, 89% men) at our center who underwent cardiopulmonary exercise testing (CPET) from January 2017 to September 2018. The primary outcome was defined as heart-transplantation, urgent left ventricular assist device (LVAD) implantation or death within 1 year of evaluation. SVRI was estimated at rest and at anaerobic threshold (AT) by VO 2 (oxygen consumption)/pulse and previously validated estimates of C[a-v]O 2 (arteriovenous difference in oxygen content). Multivariate regression selected the optimal predictors from clinical, CPET and right heart catheterization data. Results Among HFrEF patients studied, 39 (37.5%) deteriorated: 16 required heart-transplantation, 8 required LVADs and 15 died. SVRI 128% or less was the best predictor (OR 6.69, p=0.001), followed by an invasively determined resting cardiac index 2 L/min/m 2 or less (OR 3.18, p=0.02), and peak VO 2 below the International Society for Heart and Lung Transplantation (ISHLT) cut-off (OR 4.15, p=0.01). A scoring system derived from the SVRI (less than 128%: 2 points), peak VO 2 (below the ISHLT cut-off: 1 point), and cardiac index (less than 2 L/min/m 2 1 point) predicted clinical deterioration with a sensitivity of 64% and specificity of 81%. Conclusions SVRI is a non-invasive measurement that may predict deterioration in HFrEF patients more accurately than currently recommended predictors.