Magnetic resonance coronary angiography in heart transplant recipients

Annual coronary angiography is routinely performed to evaluate cardiac allografts. Recently, magnetic resonance coronary angiography has been used to imagine native coronary arteries, but its use in transplant recipients, with rapid heart rates, metallic sternal sutures, and altered cardiac orientation, has not been described. Our goal was to describe the feasibility of noninvasive magnetic resonance coronary angiography in cardiac allograft recipients, detect flow-limiting focal stenoses, and quantify the altered coronary artery orientation.

We performed magnetic resonance coronary angiography is 18 adult heart transplant recipients (15 men and 3 women) with use of a breath-hold ECG-gated segmented k-space technique. Multiple transverse and oblique images were obtained in each subject. A control population of 16 adult patients without transplant and without angiographic evidence of coronary disease provided a reference for the coronary artery length visualized by magnetic resonance coronary angiography. This technique identified the left main coronary artery in 15 of 15 transplant recipients with normal coronary anatomy. Magnetic resonance coronary angiography demonstrated a +25-degree anterior (clockwise) right coronary artery ostial rotation in transplant recipients (p = 0.0001 versus control group) with corresponding realignment of the left main ostium. By magnetic resonance coronary angiography, the mean contiguous length of coronary artery visualized in the transplant recipients was similar to that in the control subjects for all major vessels (p = not significant). Five transplant recipients had nine discrete stenoses (50% or greater luminal diameter) identified by contrast angiography, of which seven stenoses were identified as signal voids by magnetic resonance coronary angiography. coronary stenoses not seen by this technique were located in the distal one third of the artery.

These data confirm and for the first time quantify the previously observed anterior rotation of the coronary ostia, which may be used to guide coronary engagement for subsequent interventions. In addition, these data demonstrate the potential of magnetic resonance coronary angiography to image noninvasively the coronary arteries and identify focal stenoses in cardiac allograft recipients.