Structural Parameters By Cardiac Magnetic Resonance Imaging To Detect Cardiac Allograft Vasculopathy Beyond The First-Year Post-Heart Transplantation: A Prospective Single Center Analysis

Background Cardiac allograft vasculopathy (CAV) remains to be a significant complication post heart transplantation (HTx) for which early detection remains elusive. The purpose of this study was to test the utility of cardiac magnetic resonance (CMR) derived mapping techniques to non-invasively detect tissue changes in HTx patients with CAV. Methods A total of 77 prospectively recruited HTx patients (51±16 years, 44% female) beyond the first year post-HTx and 18 healthy controls (49±15 years, 33% female) underwent CMR, including T1-and T2-mapping to assess myocardial tissue changes. Data analysis included quantification of regional T2, T1 and extracellular volume (ECV) based on the 16-segment model with global (average of 16 segments) and peak (maximum segmental value out of 16 segments) values reported. ISHLT criteria was used to adjudicate CAV grade (0-3) based on coronary angiography. Results The average time between HTx and CMR was 9±6 years. CAV was angiographically detected in 73% of the HTx patients (grade 1: n=42, grade 2/3: n=14, no CAV/grade 0: n=21). Table 1 outlines global and peak structural parameters between controls and CAV subgroups. Figure 1 displays segmental structural parameters (16-segment maps) between controls and CAV subgroups. Peak T1 was significantly elevated in all HTx recipients compared to controls (p<0.05), and when comparing CAV grade 2/3 to CAV 0 (p<0.05). Global and peak ECV were significantly elevated in all HTx recipients compared to controls (p<0.01 and p<0.001, respectively) and peak ECV when comparing CAV 0 to controls (p<0.001). Global and peak T2 were significantly elevated all HTx patients compared to controls (p<0.001). Finally, Global T2 was significantly elevated in CAV 2/3 compared to CAV 0 and CAV 1 (p<0.01). Conclusions Transplanted hearts display structural alterations compared to native hearts, even in those without demonstratable allograft vasculopathy (CAV grade 0). Interestingly, no differences were observed between CAV 0 and CAV 1. Increased T1 and T2 reflective of inflammation and edema may aid in the early detection of CAV after HTx. Further research is required to assess the diagnostic value of multiparametric CMR for the non-invasive detection and classification of CAV. Cardiac allograft vasculopathy (CAV) remains to be a significant complication post heart transplantation (HTx) for which early detection remains elusive. The purpose of this study was to test the utility of cardiac magnetic resonance (CMR) derived mapping techniques to non-invasively detect tissue changes in HTx patients with CAV. A total of 77 prospectively recruited HTx patients (51±16 years, 44% female) beyond the first year post-HTx and 18 healthy controls (49±15 years, 33% female) underwent CMR, including T1-and T2-mapping to assess myocardial tissue changes. Data analysis included quantification of regional T2, T1 and extracellular volume (ECV) based on the 16-segment model with global (average of 16 segments) and peak (maximum segmental value out of 16 segments) values reported. ISHLT criteria was used to adjudicate CAV grade (0-3) based on coronary angiography. The average time between HTx and CMR was 9±6 years. CAV was angiographically detected in 73% of the HTx patients (grade 1: n=42, grade 2/3: n=14, no CAV/grade 0: n=21). Table 1 outlines global and peak structural parameters between controls and CAV subgroups. Figure 1 displays segmental structural parameters (16-segment maps) between controls and CAV subgroups. Peak T1 was significantly elevated in all HTx recipients compared to controls (p<0.05), and when comparing CAV grade 2/3 to CAV 0 (p<0.05). Global and peak ECV were significantly elevated in all HTx recipients compared to controls (p<0.01 and p<0.001, respectively) and peak ECV when comparing CAV 0 to controls (p<0.001). Global and peak T2 were significantly elevated all HTx patients compared to controls (p<0.001). Finally, Global T2 was significantly elevated in CAV 2/3 compared to CAV 0 and CAV 1 (p<0.01). Transplanted hearts display structural alterations compared to native hearts, even in those without demonstratable allograft vasculopathy (CAV grade 0). Interestingly, no differences were observed between CAV 0 and CAV 1. Increased T1 and T2 reflective of inflammation and edema may aid in the early detection of CAV after HTx. Further research is required to assess the diagnostic value of multiparametric CMR for the non-invasive detection and classification of CAV.