Right Ventricular Function on Cardiovascular Magnetic Resonance Imaging and Long-Term Outcomes in Stable Heart Transplant Recipients

Abstract

Background: In heart transplant recipients, right ventricular (RV) dysfunction may occur for a variety of reasons. Whether RV dysfunction in the stable phase after heart transplantation is associated with long-term adverse outcomes is unknown. We aimed to determine the long-term prognostic significance of RV dysfunction identified on cardiovascular magnetic resonance imaging (CMR) at least 1 year after heart transplantation.

Methods: In consecutive heart transplant recipients who underwent CMR for surveillance, we assessed 2 CMR measures of RV function: RV ejection fraction and RV global longitudinal strain (RVGLS). We investigated associations between RV dysfunction and a composite end point of death or major adverse cardiac events, including retransplantation, nonfatal myocardial infarction, coronary revascularization, and heart failure hospitalization.

Results: A total of 257 heart transplant recipients (median age, 59 years; 75% men) who had CMR at a median of 4.3 years after heart transplantation were included. Over a median follow-up of 4.4 years after the CMR, 108 recipients experienced death or major adverse cardiac events. In a multivariable Cox regression analysis adjusted for age, time since transplantation, indication for transplantation, cardiac allograft vasculopathy, history of rejection, and CMR covariates, RV ejection fraction was not associated with the composite end point, but RVGLS was independently associated with the composite end point with a hazard ratio of 1.08 per 1% worsening in RVGLS ([95% CI, 1.00-1.17]; P=0.046). RVGLS provided incremental prognostic value over other variables in multivariable analyses. The association was replicated in subgroups of recipients with normal RV ejection fraction and recipients with late gadolinium enhancement imaging. A similar association was seen with a composite end point of cardiovascular death or major adverse cardiac events.

Conclusions: CMR feature tracking-derived RVGLS assessed at least 1 year after heart transplantation was independently associated with the long-term risk of death or major adverse cardiac events. Future studies should investigate its role in guiding clinical decision-making in heart transplant recipients.

Keywords: clinical decision-making; global longitudinal strain; heart transplantation; magnetic resonance imaging; myocardial infarction; prognosis.

Figure 1.. Examples of heart transplant recipients from the study.

The recipient at the top had RVGLS of −19.2% (better than the median of −14.4%) and was alive without MACE 15 years after the CMR. The recipient at the bottom had RVGLS of −11.5% (worse than the median of −14.4%) and experienced MACE 9 months after the CMR. CMR = cardiovascular magnetic resonance imaging; MACE = major adverse cardiac events; RVGLS = right ventricular global longitudinal strain

Figure 2.. Kaplan-Meier cumulative incidence curves for death or MACE.

Panel A shows cumulative incidence curves comparing death or MACE between heart transplant recipients with abnormal RVEF (orange) and normal RVEF (green). Panel B shows cumulative incidence curves comparing death or MACE between heart transplant recipients with RVGLS worse than the median (orange) and RVGLS better than the median (green). Each vertical tick on the curves represents a censored patient. CMR = cardiovascular magnetic resonance imaging; MACE = major adverse cardiac events; RVEF = right ventricular ejection fraction; RVGLS = right ventricular global longitudinal strain