Prognostic value of early cardiac magnetic resonance first-pass perfusion assessment of microcirculatory dysfunction for acute rejection after heart transplantation

Q: What are the key findings of this study?

Impaired myocardial microvascular function at 3 months post-transplantation, reflected by reduced Upslope on CMR resting first-pass perfusion, independently predicted acute rejection within 2 years (aHR 0.78).

Q: What is the clinical evidence from this study?

Study design: Cohort. Population: Acute rejection after heart transplantation (n=111). Intervention: Cardiac magnetic resonance resting first-pass perfusion parameters (TTM, Upslope, MaxSI) vs. Clinical variables alone (age and BMI) / Normal perfusion. Primary outcome: Acute rejection confirmed by pathological diagnosis on endomyocardial biopsy or clinically diagnosed within 2 years after heart transplantation (aHR 0.78, 95% CI 0.71, 0.86, p=<0.001).

Q: What does this research mean for the field?

Impaired myocardial microvascular function at 3 months post-transplantation, reflected by reduced Upslope on CMR resting first-pass perfusion, independently predicts acute rejection within 2 years (adjusted HR 0.78). Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

Q: What question did this study set out to answer?

To assess the prognostic value of resting first-pass cardiac magnetic resonance perfusion parameters measured at 3 months post-transplantation for predicting acute rejection within 2 years.

Ke Han; Yuelong Yang; Liqi Cao; Chang Liu; Chulan Ou; 莫才英; Chun Luo; Yingying Bao; Min Wu; Hui Liu

doi:10.21037/cdt-2026-0215

August 1, 2026Cardiovascular Diagnosis and TherapyOpen Access

Prognostic value of early cardiac magnetic resonance first-pass perfusion assessment of microcirculatory dysfunction for acute rejection after heart transplantation

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Key result

Higher CMR perfusion upslope at 3 months is linked to ~22% lower 2-year rejection risk.

aHR 0.78
95% CI 0.71, 0.86
P<0.001
n=111

Figures

Why the study?

The prognostic value of cardiac magnetic resonance resting first-pass perfusion imaging for evaluating microcirculatory dysfunction to predict acute rejection after heart transplantation remains unclear.

Does early cardiac magnetic resonance resting first-pass perfusion assessment predict acute rejection within 2 years in heart transplant recipients?

Key Points

To assess the prognostic value of resting first-pass cardiac magnetic resonance perfusion parameters measured at 3 months post-transplantation for predicting acute rejection within 2 years.
Retrospective single-center analysis of 79 heart transplant recipients (mean age 42.3±11.7 years; 73.4% male) and 32 healthy controls.
Resting first-pass perfusion CMR was performed 3 months after transplantation to assess time to peak myocardial signal intensity (TTM), Upslope, and maximum signal intensity (MaxSI).
Recipients were followed for a median of 24 months (IQR, 20.5–24.0 months) for the primary endpoint of acute rejection diagnosed pathologically via endomyocardial biopsy or clinically.
Acute rejection occurred in 21 of 79 recipients (26.6%), who exhibited significantly longer TTM, lower Upslope, and lower MaxSI at 3 months compared with non-rejection recipients and controls (all P<0.001).
Multivariable Cox regression adjusting for age and BMI showed TTM (aHR: 1.07 [1.04, 1.10], P<0.001), Upslope (aHR: 0.78 [0.71, 0.86], P<0.001), and MaxSI (aHR: 0.97 [0.95, 0.98], P<0.001) were independent predictors of acute rejection.
Adding Upslope to the clinical model provided the greatest incremental prognostic performance, increasing the C-index from 0.707 to 0.889 (continuous NRI: 1.049, IDI: 0.343; all P<0.001).

Study Design

Type

Cohort (n=111)

Multicenter

No

Structured PICO

Does early cardiac magnetic resonance resting first-pass perfusion assessment predict acute rejection within 2 years in heart transplant recipients?

P

Population

79 adult heart transplant recipients without diabetes or severe renal dysfunction, along with 32 healthy controls, followed for a median of 24 months to evaluate the prognostic value of CMR first-pass perfusion for acute rejection.

E

Exposure

Cardiac magnetic resonance (CMR) resting first-pass perfusion imaging (assessing TTM, Upslope, and MaxSI) performed at 3 months after heart transplantation.

O

Outcome

Acute rejection confirmed by pathological diagnosis on endomyocardial biopsy or clinically diagnosed within 2 years after heart transplantation.hard clinical

Main Result

Hazard Ratio: 0.78 (95% CI 0.71–0.86)

p-value: p=<0.001

CMR resting first-pass perfusion parameters measured at 3 months post-heart transplant independently predict acute rejection within 2 years, providing significant incremental prognostic value over standard clinical variables.

Limitations

Single-center retrospective study with a relatively small sample size and limited number of positive acute rejection events.
Endomyocardial biopsy was not performed in all patients; majority of AR cases were diagnosed clinically, introducing potential misclassification bias.
Did not perform invasive coronary microvascular assessments (like IMR) for direct comparison with CMR parameters.
Only resting perfusion was evaluated; stress perfusion or myocardial perfusion reserve index was not available.
Excluded patients who experienced AR before the 3-month CMR or died perioperatively, potentially introducing survivor bias.
Excluded patients with diabetes and severe renal dysfunction, limiting generalizability.
Lack of data on other important immunological risk factors such as panel reactive antibody (PRA) levels.
Single-center design
Retrospective analysis
Lack of biopsy-confirmed acute rejection for all patients (some diagnosed clinically)

Implication

May aid early post-transplant rejection risk stratification; hypothesis-generating and requires prospective validation before clinical adoption.

Abstract

Background: Acute rejection (AR) remains a major obstacle to success after heart transplantation (HT). Impaired microcirculatory function is linked to a higher risk of AR. The value of cardiac magnetic resonance (CMR) resting first‑pass perfusion imaging for evaluating microcirculatory function to predict subsequent AR after HT remains unclear. We aimed to evaluate the prognostic value of CMR resting first‑pass perfusion parameters measured early after HT for AR. Methods: This single-center retrospective study analyzed data from 79 HT recipients, including 21 with AR [HT (AR+)] and 58 without AR [HT (AR−)], and 32 healthy volunteers. CMR examination was performed at 3 months after HT to assess myocardial perfusion. Resting first-pass perfusion parameters, including time to peak myocardial signal intensity (TTM), Upslope, and maximum signal intensity (MaxSI) were analyzed. Univariable and multivariable Cox regression analyses were performed to identify predictors of AR within 2 years after HT. Incremental prognostic value was evaluated using C-index, continuous net reclassification index (NRI), and integrated discrimination improvement (IDI). P value <0.05 was considered statistically significant. Results: During a median follow‑up of 24 months, 21 HT recipients (26.6%) experienced AR. Patients with AR showed significantly longer TTM, lower Upslope and MaxSI at 3 months after HT compared with non‑AR patients and controls (all P<0.001). TTM [adjusted hazard ratio (aHR): 1.07 (1.04, 1.10), P<0.001], Upslope [aHR: 0.78 (0.71, 0.86), P<0.001], and MaxSI [aHR: 0.97 (0.95, 0.98), P<0.001] were independent predictors of AR after adjusting for age and body mass index (BMI). Adding TTM, Upslope, and MaxSI individually to the clinical model (age + BMI) significantly improved discriminant and reclassification ability for risk of AR (C‑index: 0.803, 0.889, 0.869 vs. 0.707; continuous NRI: 0.755, 1.049, 1.025; IDI: 0.139, 0.343, 0.340; all P<0.05), with Upslope demonstrating the highest incremental value. Conclusions: CMR resting first‑pass perfusion parameters acquired early after HT that reflect microcirculatory dysfunction are independent prognostic markers of AR within 2 years and provide incremental prognostic value over clinical variables to guide personalized post‑transplant management.

Discussion

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Cite This Study

Han et al. (2026) conducted a cohort in Acute rejection after heart transplantation (n=111). Cardiac magnetic resonance resting first-pass perfusion parameters (TTM, Upslope, MaxSI) vs. Clinical variables alone (age and BMI) / Normal perfusion was evaluated on Acute rejection confirmed by pathological diagnosis on endomyocardial biopsy or clinically diagnosed within 2 years after heart transplantation (aHR 0.78, 95% CI 0.71, 0.86, p=<0.001). Impaired myocardial microvascular function at 3 months post-transplantation, reflected by reduced Upslope on CMR resting first-pass perfusion, independently predicted acute rejection within 2 years (aHR 0.78).

synapsesocial.com/papers/6ad0fcc53afa093ea9acffee https://doi.org/10.21037/cdt-2026-0215

Topics

Heart transplantation

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Prognostic value of early cardiac magnetic resonance first-pass perfusion assessment of microcirculatory dysfunction for acute rejection after heart transplantation

Figures

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

Topics

Prognostic value of early cardiac magnetic resonance first-pass perfusion assessment of microcirculatory dysfunction for acute rejection after heart transplantation

Figures

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

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