Tricuspid regurgitant jet velocity and myocardial tissue Doppler parameters predict mortality in a cohort of patients with sickle cell disease spanning from pediatric to adult age groups - revisiting this controversial concept after 16 years of additional evidence

Abstract

Sickle cell disease (SCD) is a monogenic hemoglobinopathy associated with significant morbidity and mortality. Cardiopulmonary, vascular and sudden death are the reasons for the majority of young adult mortality in SCD. To better understand the clinical importance of multi-level vascular dysfunction, in 2009 we assessed cardiac function including tricuspid regurgitant jet velocity (TRV), tissue velocity in systole(S') and diastole (E'), inflammatory, rheologic and hemolytic biomarkers as predictors of mortality in patients with SCD. With up to 9 years of follow up, we determined survival in 95 children, adolescents and adults with SCD. Thirty-eight patients (40%) were less than 21 years old at initial evaluation. Survival and Cox proportional-hazards analysis were performed. There was 19% mortality in our cohort, with median age at death of 35 years. In the pediatric subset, there was 11% mortality during the follow up period. The causes of death included cardiovascular and pulmonary complications in addition to other end-organ failure. On Cox proportional-hazards analysis, our model predicts that a 0.1 m/s increase in TRV increases risk of mortality 3%, 1 cm/s increase in S' results in a 91% increase, and 1 cm/s decrease in E' results in a 43% increase in mortality. While excluding cardiac parameters, higher plasma free hemoglobin was significantly associated with risk of mortality (p=.049). In conclusion, elevated TRV and altered markers of cardiac systolic and diastolic function predict mortality in a cohort of adolescents and young adult patients with SCD. These predictors should be considered when counseling cardiovascular risk and therapeutic optimization at transition to adult providers.

Figure 1:

Kaplan Meier survival curve shows Higher TRV (>250 cm/s) (p=0.018) is associated with the risk of mortality in patients with Sickle Cell Disease. 7-Years survival for the category TRV>250 is 73% (CI 53%–86%) and for the category TRV ≤ 250 is 94% (CI 83%–98%); TRV= Tricuspid Regurgitant Jet Velocity.

Figure 2:

Multifactorial etiology of elevated TRV. Elevated TRV represents the superposition of increased cardiac output on micro/macrovascular disease in the lungs and poor left ventricular compliance. (Figure adapted from The Open University); TRV= Tricuspid Regurgitant Jet Velocity; LV=Left ventricle; RV=Right ventricle; LA=Left atrium