Predictive Role of Soluble ST2 in Patients on Left Ventricular Assist Device Support

Purpose

Soluble suppression of tumorigenicity-2 (sST2) is a prognostic indicator for mortality in heart failure (HF) patients and therefore a valuable tool in risk stratification. After implantation of a continuous flow left ventricular assist device (cf-LVAD), sST2 levels drop significantly. Whether sST2 levels are predictive of adverse outcome in patients on LVAD support remains unknown. We hypothesized that elevated sST2 predict mortality in LVAD patients.

Methods

Between March 2006 and July 2021, 422 patients were primarily implanted with a HeartMate II, HeartMate 3 or HeartWare LVAD in a single centre. sST2 was measured during regular outpatient visits and from biobanked samples if available. All sST2 measurements of these patients until July 2021 were retrieved. Time varying covariate cox regression was used to estimate the effect of sST2 on the primary outcome, stratified for device type and adjusted for the pre-operative variables age, sex, temporary support at implantation, INTERMACS 1 status and ischemic etiology. Primary outcome was death or urgent heart transplant (HTx) and patients were censored if they were explanted, received non-urgent HTx, or for ongoing support at the end of the follow-up.

Results

Post-operative sST2 measurements of 252 LVAD patients were included for analysis, of which 29%, 23%, and 48% received a HeartWare, HeartMate II or HeartMate 3, respectively. The median age was 55 and 64% were male. Median follow-up time was 899 days, during which 35 patients died, 12 patients received urgent HTx and 31 patients received HTx after normal listing. In total, 1475 post-operative sST2 measurements were used for analysis, with a median of 28.2 ng/ml (inter quartile range: 20.8 ng/ml). The multivariate adjusted time dependent cox model resulted in a HR of 1.02, with p<0.001 for sST2.

Conclusion

sST2 is predictive for all-cause mortality in patients on LVAD support. Therefore, a closer follow-up may be recommended in patients with high sST2 measures. In addition, further research is warranted into the mechanisms of elevated sST2 in LVAD patients and possible targeted interventions to improve prognosis.