Fibrotic Plaque and Microvascular Dysfunction Predict Early Cardiac Allograft Vasculopathy Progression After Heart Transplantation: The Early Post Transplant Cardiac Allograft Vasculopathy Study

Background: Early cardiac allograft vasculopathy (CAV) prognostication is needed to improve long-term outcomes after heart transplantation. We characterized first year posttransplant coronary anatomic-physiologic alterations to determine predictors of early CAV progression.

Methods: Heart transplant recipients at 2 institutions (enrolled January 2018 to March 2021) underwent prospective evaluation 3 and 12-month posttransplant with angiography and left anterior descending artery intravascular ultrasound, optical coherence tomography, fractional flow reserve, coronary flow reserve, and index of microcirculatory resistance measurements. CAV progression was assessed by intravascular ultrasound change in percentage intimal volume from baseline to 12-month follow-up.

Results: Eighty-two patients (mean age, 51 years; 60% men) completed evaluation at mean 13.8 and 56.3 weeks posttransplant. Donor atherosclerosis (baseline intravascular ultrasound maximal intimal thickness, ≥0.5 mm) was evident in 50%. De novo (follow-up maximal intimal thickness, ≥0.5 mm) and rapidly progressive CAV (maximal intimal thickness, ≥0.5-mm increase from baseline) developed in 24% and 13%, respectively. On optical coherence tomography, baseline to follow-up median intimal volume increased 42% (0.58 mm³/mm), percentage intimal volume increased 44% (4.6%), vessel volume decreased 4% (-0.50 mm³/mm) and lumen volume decreased 9% (-1.02 mm³/mm); P<0.05 for all. Fibrotic plaque was the predominant morphology: baseline, 29% and follow-up, 50%. Coronary physiology was abnormal in 41% at baseline and 45% at follow-up, with 1 in 5 patients having microvascular dysfunction (index of microcirculatory resistance, ≥25). On multivariable linear regression analysis, recipient male sex, fibrotic plaque, and index of microcirculatory resistance were independent predictors of coronary disease progression.

Conclusions: Fibrotic plaque on optical coherence tomography and index of microcirculatory resistance early posttransplant predict CAV progression in the first year of transplantation.

Registration: URL: https://www.

Clinicaltrials: gov; Unique identifier: NCT03217786.