The role of non-invasive imaging modalities in cardiac allograft vasculopathy: an updated focus on current evidences

Abstract

Cardiac allograft vasculopathy (CAV) is an obliterative and diffuse form of vasculopathy affecting almost 50% of patients after 10 years from heart transplant and represents the most common cause of long-term cardiovascular mortality among heart transplant recipients. The gold standard diagnostic technique is still invasive coronary angiography, which however holds potential for complications, especially contrast-related kidney injury and procedure-related vascular lesions. Non-invasive and contrast-sparing imaging techniques have been advocated and investigated over the past decades, in order to identify those that could replace coronary angiography or at least reach comparable accuracy in CAV detection. In addition, they could help the clinician in defining optimal timing for invasive testing. This review attempts to examine the currently available non-invasive imaging techniques that may be used in the follow-up of heart transplant patients, spanning from echocardiography to nuclear imaging, cardiac magnetic resonance and cardiac computed tomography angiography, weighting their advantages and disadvantages.

Keywords: CAV; CCTA; CMR; Echocardiography; Heart transplant; SPECT.

Fig. 1

Central illustration. This figure shows the different parameters that could be assessed with each non-invasive imaging modality. The sensitivity of each parameter tends to decrease from the outer layers to the inner ones. CAC: coronary artery calcium; CAV: cardiac allograft vasculopathy; CCTA: cardiac computed tomography angiography; CMR: cardiac magnetic resonance; DS: dobutamine-stress ECD: echocardiography; GLS: global longitudinal strain: LVEF: left ventricular ejection fraction; MBF: myocardial blood flow; PET: positron emission tomography; SPECT: single-photon emission computed tomography; WMAs: wall motion abnormalities

Fig. 2

Diastolic dysfunction in presence of cardiac allograft vasculopathy. The left picture shows a normal diastolic function, as indicated by pulsed wave trans-mitral Doppler velocities and deceleration time of E wave, in a heart transplant patient without cardiac allograft vasculopathy. On the other hand, the right picture shows a restrictive diastolic pattern in presence of grade 3 cardiac allograft vasculopathy

Fig. 3

Left ventricular global longitudinal strain and cardiac allograft vasculopathy. This picture shows left ventricular longitudinal strain and three-layer specific longitudinal strain in three different heart transplant patients, with grade 3 cardiac allograft vasculopathy (CAV), with grade 1 CAV and without CAV, from left to right respectively. Left ventricular longitudinal strain assessed in apical 4-chamber view appears significantly reduced in presence of diffuse CAV, whereas it is almost comparable to normal subjects in the absence of this complication

Fig. 4

Invasive coronary angiography vs coronary computed tomography angiography. Presence of coronary allograft stenosis in proximal-middle left anterior descending artery (LAD, continuous arrows) and proximal circumflex artery (LCx, dashed arrow), as detected by either invasive coronary angiography (ICA) and 64-slice multidetector computed tomography (MDCT). ICA, invasive coronary angiography; LAD, left anterior descending artery; LCx, left circumflex artery; MDCT, multidetector computed tomography. Adapted from Nunoda S et al., 2010 (10.1253/circj.cj-09–0800) [84]

Fig. 5

Myocardial blood flow quantification positron emission tomography. Inferolateral reduction in myocardial blood flow (MBF), suggestive of significant CAV in left circumflex artery (LCx), and milder degrees of myocardial ischemia during peak hyperemia, suggestive of diffuse CAV. ICA, invasive coronary angiography; LAD, left anterior descending artery; LCx, left circumflex artery; LM, left main artery; LV, left ventricle; LVEF, left ventricular ejection fraction; MBF, myocardial blood flow; OM, obtuse marginal; RV, right ventricle. Adapted from Bravo PE et al., 2018 (10.1093/eurheartj/ehx683) [8776]

Fig. 6

Invasive coronary angiography vs cardiac magnetic resonance. Evidence of diffuse wall thickening in the distal left anterior descending artery (LAD) and stenosis in the left circumflex artery (LCx), as revealed by invasive coronary angiography (ICA). Cardiac magnetic resonance (CMR) did not detect any of these defects. CMR, cardiac magnetic resonance; ICA, invasive coronary angiography; LAD, left anterior descending artery; LCx, left circumflex artery. Adapted from Nunoda S et al., 2010 (10.1253/circj.cj-09–0800) [84]