Quantitative myocardial blush grade for the detection of cardiac allograft vasculopathy

Korosoglou G.
Riedle N.
Erbacher M.
Dengler T.J.
Zugck C.
Rottbauer W.
Hardt S.
Bekeredjian R.
Kristen A.
Giannitsis E.
Osman N.F.
Dickhaus H.
Katus H.A.

Background: Cardiac allograft vasculopathy (CAV) progressively compromises microvascular perfusion and function in heart transplantation (HTx)-recipients. The aim of our study was to investigate the ability of quantitative myocardial blush grade (MBG) to detect CAV. Methods: In consecutive HTx-recipients (n = 72) who underwent surveillance cardiac catheterization, MBG was assessed visually and quantitatively, by analyzing the time course of contrast agent intensity rise. Hereby, the parameter Gmax/Tmax was calculated as the plateau of grey-level intensity (Gmax) divided by the time-to-peak intensity (Tmax). HTx-recipients and 18 healthy volunteers underwent cardiac magnetic resonance, to assess diastolic strain rates and myocardial perfusion reserve during pharmacologic hyperemia. Results: Significant correlations were observed between Gmax/Tmax with perfusion reserve and with mean diastolic strain rates (r2 = 0.68 and r2 = 0.58, P < .001 for both). Visual and quantitative MBG using a cutoff value of Gmax/Tmax = 2.7/s yielded significantly higher accuracy than stenosis severity on coronary angiograms for the detection of impaired microvascular integrity as a surrogate marker for CAV (AUC = 0.78, SE = 0.06, 95% CI = 0.66-0.87 for lumen narrowing versus AUC = 0.91, SE = 0.03, 95%CI = 0.84-0.97 for Gmax/Tmax; P < .01). Furthermore, quantitative MBG provided more robust prediction of survival (χ2= 14.0, P < .001), compared to visually estimated blush (χ2= 5.4, P = .02) and to coronary lumen narrowing assessment, (χ2= 4.8, P = .04). Conclusions: Quantification of MBG can be performed on coronary angiograms of HTx-recipients, and may help with the identification of early CAV in patients with impaired perfusion reserve but without angiographically evident atherosclerosis. © 2010 Mosby, Inc. All rights reserved.