Long-term temporal trend in plaque eccentricity assessed through intravascular ultrasound imaging after heart transplantation

BACKGROUND: Cardiac allograft vasculopathy (CAV) is a leading cause of graft failure and death after heart transplantation (HTx). Conventionally, CAV is characterized by concentric intimal thickening, however the long-term plaque progression patterns are elusive. This study aimed to assess the plaque characteristics in a temporal manner post-HTx using virtual histology intravascular ultrasonography (VH-IVUS). METHODS: From 279 patients, we included 50 patients who underwent serial VH-IVUS assessment at three assessment points (A1: 0-1 year, A2: 3-5 years, A3: 7-10 years) post-HTx. Eccentricity index (EI) was defined as (maximum intimal thickness [MIT] - minimum intimal thickness)/MIT and evaluated in 39 patients with significant plaque (MIT > 0.50 mm at the A3). Differences in VH-IVUS findings between timepoints (Early: A1-2 [median 3.0] and Late: A2-3 [median 4.1 years]) were investigated. RESULTS: Of 50 patients, age was 51 ± 13 years, 36 (72 %) were males. In both Early and Late, the plaque volume index showed a significant increase, however, the rate of progression was significantly slower in Late (5.8 % vs 2.4 %, p = 0.015). The EI showed decrease in Early, compared to increase in Late (-0.040 vs 0.003, p = 0.036). Patients with higher EI change in Late had significantly lower proportion of fibrous plaque (p = 0.002) and higher dense calcium (p = 0.022) at A3. CONCLUSIONS: In the Late, HTx patients showed more eccentric plaque progression with lower fibrous plaque composition. These results suggest that typical and conventional atherosclerosis-like plaque progression can also occur in CAV during long-term follow-up, suggesting that treatment strategies based on insights into atherosclerosis may be useful.