Admission hemodynamics and timing of impella 5.5 as predictors of 1-year mortality after heart transplantation

Background

Outcomes in high-acuity transplant candidates may be influenced by admission hemodynamic profile and the timing of escalation to temporary mechanical circulatory support.

Objectives

Evaluate the association between admission hemodynamic profile, time-to-Impella escalation, and 1-year post-transplant mortality.

Methods

We conducted a single-center retrospective cohort study of Impella 5.5–bridged heart transplant recipients from 2020 to 2025. Admission hemodynamic parameters were defined by the first invasive profile obtained prior to Impella 5.5 insertion. Timing metrics included admission-to-Impella and right heart catheterization-to-Impella intervals. We defined early tMCS placement as <12 days from admission.

The primary outcome was 1-year all-cause mortality. Continuous variables are reported as median (IQR) and categorical variables as n (%). Groups were compared using the Wilcoxon rank-sum test and Fisher’s exact test, as appropriate.

Given the low event rate, Firth-penalized logistic regression was used for univariable and parsimonious multivariable analyses, adjusting for age, admission hemodynamic severity, and time-to-Impella. Cox proportional hazards models were used as sensitivity analyses.

Results

Among 165 recipients, 9 deaths (5.5%) occurred at 1 year. 59 patients were classified as delayed, and 106 as having an early implant timeframe. The median admission-to-Impella time was 8 days (IQR 3–17). Baseline age and admission hemodynamic measures, including right atrial pressure (RAP), mean pulmonary artery pressure (mPAP), and cardiac index (CI), were similar between groups. Time-to-Impella was significantly longer in the delayed group (median 22 vs 5 days, p < 0.001).

One-year mortality was numerically higher in the delayed group compared with the early group (10.2% vs 2.8%), although this difference did not reach statistical significance (unadjusted OR 3.89, 95% CI 0.93–16.16; p = 0.071).

In univariable analyses, admission hemodynamic variables, RAP showed a borderline association (OR 1.09 per mmHg, 95% CI 1.00–1.20; p = 0.061) with mortality. In parsimonious multivariable Firth models adjusting for age and admission hemodynamic severity, time-to-Impella (per 5 days) was not independently associated with mortality (OR 1.12, 95% CI 0.84–1.35; p = 0.37). Higher baseline RAP remained associated with increased 1-year mortality, with a borderline association (OR 1.10 per mmHg, 95% CI 1.00–1.21; p = 0.049).

Conclusions

Our single-center experience highlights that patients with elevated RAP are associated with an independent risk of 1-year mortality. Although delayed support was associated with numerically higher unadjusted mortality, timing was not an independent predictor after adjustment, highlighting the dominant role of physiologic severity at presentation and the need for earlier recognition of high-risk hemodynamic profile.Univariable and Multivariable AnalysisBaseline Characteristics