Abstract Body (Do not enter title and authors here): Background: Microvascular dysfunction after heart transplantation leads to restrictive cardiac allograft physiology (RCP), which is classified to severe coronary allograft vasculopathy (CAV); however, the prognosis of RCP remains unclear. This study aimed to elucidate the prognosis of RCP in comparison with that of severe angiographic CAV.
Methods: We assessed patients with RCP defined as mean right atrial pressure >12 mmHg, pulmonary capillary wedge pressure >25 mmHg, and cardiac index <2.0 L/min/m² who underwent heart transplantation between 2004 and 2023. The primary outcome was death or re-transplantation.
Results: Of the 116 patients with severe CAV, 42 had RCP (RCP-CAV group) and 74 had severe angiographic CAV without RCP (Angio-CAV group). A significantly shorter time from heart transplantation to diagnosis and lower subsequent percutaneous catheter intervention after diagnosis were seen in the RCP-CAV group than in the Angio-CAV group (both p<0.001). The incidence of death or re-transplantation within 5 years after was significantly higher in the RCP-CAV group than in the Angio-CAV group (69.0% vs 50.0%, p=0.047). Freedom from death or re-transplantation at 5 years was significantly worse in the RCP-CAV group compared to the Angio-CAV group (18.4% vs 35.4%, p=0.001). In the Cox proportional hazard model, RCP was independently associated with an increased risk of death or re-transplantation (Hazard ratio 2.08, 95% Confidence intervals 1.26-3.44, p=0.004).
Conclusions: The prognosis of patients with RCP was significantly worse than that of patients with severe angiographic CAV. The early detection of microvascular dysfunction and re-transplantation listing may improve the prognosis of patients with RCP.