Relative contributions of intimal hyperplasia and vascular remodeling in early cardiac transplant-mediated coronary artery disease

The relative contribution of intimal hyperplasia and vascular remodeling in early transplant coronary artery disease (TxCAD) is unknown. This study was designed to determine the contributions of vascular remodeling and intimal hyperplasia in the initial year after transplantation by intravascular ultrasound (IVUS). Twenty-five patients underwent baseline (<6 weeks after transplant) and 1-year angiography and IVUS to evaluate total vessel, luminal, and intimal + medial areas in ≥3 segments of the coronary artery. Nine patients had donor atherosclerotic disease on baseline study (23% of segments), and at 1-year, 21 patients (84%) had intimal hyperplasia (70% of segments). Fourteen patients had positive remodeling in all arterial segments, whereas the remaining 11 had positive and negative remodeling in the same vessel. Mean plaque area and total vessel area increased significantly (p = 0.0001) in proximal, mid, and distal segments, whereas total vessel area was most pronounced in distal segments. Luminal area did not change over time. Of the 87 segments evaluated, 68 (78%) had an increase in total vessel area, 57 (66%) had intimal growth, and 54 (62%) had an increase in luminal area. Although changes in total vessel and luminal area were closely correlated, a decrease in luminal area was associated with positive and negative remodeling. In conclusion, luminal area is generally maintained during the initial transplant year despite significant intimal hyperplasia due to positive remodeling. Reduction in the luminal area results from either inadequate positive remodeling or negative remodeling without intimal growth and often occurs in the same artery.