While no definite well-validated surrogate marker for late cardiac allograft outcome is available, the early detection of cardiac allograft vasculopathy represents the 'key' candidate as an effective surrogate. Intravascular ultrasound detected intimal thickening has been noted to possess prognostic capability despite the presence of a normal coronary angiogram. Several prospective investigations have pointed to accurate thresholds of intimal thickening that are prognostically relevant and predict not only future angiographic disease but also hard allograft related endpoints including ischemic cardiac events, allograft failure, and death. Because of the resolution of intravascular ultrasound, this technique accords reproducibility and the ability to standardize the degree of intimal thickening over time. Other candidates that may serve as surrogates once appropriately evaluated include measures of allograft pump function, intragraft histology, and peripheral markers including but not limited to structural proteins (cardiac specific troponins), inflammatory markers (CRP), fibrogenic markers (TGF-beta, fibroblast growth factor), and immune markers (anti-HLA Ab and indirect alloantibodies).