Detection of Vein Graft Disease Using High-Resolution Magnetic Resonance Angiography

Abstract

Background-The application of previous magnetic resonance (MR) angiography techniques has enabled noninvasive differentiation between patent and occluded coronary artery bypass grafts. However, the detection of graft stenosis remains difficult. The purpose of our study was to determine the accuracy of high-resolution navigator-gated 3-dimensional (3-D) MR angiography in detecting vein graft disease. Methods and Results-MR angiography was performed in addition to coronary angiography with quantitative coronary analysis in 56 vein grafts from 38 patients (mean age 66.6Ϯ9.3 years), who presented with recurrent chest pain after bypass surgery. Eighteen grafts showed a luminal stenosis Ն50%, 11 grafts a stenosis Ն70%, and 6 grafts were occluded. All MR angiograms were evaluated independently by 2 blinded observers, who scored the presence of graft occlusion and graft stenosis Ն50% and Ն70% with a confidence level of 1 to 10. MR image quality was judged as insufficient in 6 grafts and these were excluded. Receiver-operator characteristic analysis revealed an area under the curve of 0.89 and 0.89 for identifying graft occlusion, 0.81 and 0.87 for stenosis Ն50%, and 0.82 and 0.79 for stenosis Ն70% for the 2 observers, respectively. Interobserver agreement in assessing graft occlusion and stenosis Ն50% and Ն70% was 94% (ϭ0.74, rϭ0.81), 72% (ϭ0.40, rϭ0.66), and 82% (ϭ0.53, rϭ0.72)

Non-invasive assessment of coronary artery bypass graft with retrospectively ECG-gated four-row multi-detector spiral computed tomography

“…Promising results have been recently reported for magnetic resonance imaging (MRI). Langerak et al [14] Fig. 3 Seventy-one-year-old man with a recent non-Q wave myocardial infarction who underwent CABG surgery with LIMA to LAD and right internal mammary artery (RIMA) to obtuse marginal branch.…”

“…Coronary angiography (CA) is still the diagnostic tool of reference for evaluating the status of grafts and coronary arteries; however, it is an invasive procedure, requires hospitalization and is characterized by a small but relevant risk of untoward events [5]. Attempts have been made to assess venous graft patency with non-invasive methods, including electron beam computed tomography (EBCT) [6][7][8] and magnetic resonance imaging (MRI) [9][10][11][12][13][14][15], with encouraging results. However, a routine use of these two modalities can be limited by inadequate scan coverage, clinical availability and higher costs for EBCT or long acquisition time, lower spatial resolution and claustrophobia for MRI.…”

Coronary Magnetic Resonance Angiography

“…More recently, there has been renewed interest to assess the presence of graft stenoses. A recent single-center study showed an intermediate sensitivity but high specificity for detection of focal graft stenoses [22] (Figure 11). …”

“…However, imaging is hindered by the presence of sternal wires, graft markers or surgical clips that create local field inhomogeneities and susceptibility artifacts ( Figure 10). The patency of bypass grafts can be ascertained if evidence of blood flow can be identified in at least two levels along the course of the graft [22][23][24][25]. Even using slow conventional CMRA techniques, the patency of bypass grafts can be accurately assessed.…”

Nichtinvasive Angiographie koronarer Bypassgefäße mit dem Cardio-CT in einer kardiologischen Praxis

“…Obwohl die Schichtdicke beim MRT durch längere Aufnahmezeiten von 6 mm auf 3 mm verringert werden kann, lässt sich dies nicht an einer verbesserten Bildqualität erkennen [41]. Mit der Navigatortechnik fand sich an 38 Patienten eine Sensitivität von 65% bis 82% bei einer Spezifität von 82% bis 88% für die Erkennung von ≥ 50%igen Stenosen in Bypassgefäßen [30].…”