Combo of CT coronary angiography and CT myocardial perfusion may detect cardiac allograft vasculopathy earlier

"Transplant centres and clinicians should explore how this approach can enhance early detection and intervention, potentially improving graft survival," the researcher suggested.

Cardiac allograft vasculopathy is a condition that affects people with heart transplantation. It causes narrowing and eventually blocking of the blood vessels supplying blood to the heart muscle itself. CAV is a major obstacle that limits long-term graft survival. Therefore, there is a need for effective noninvasive surveillance modalities reflecting both coronary artery and microvascular components of CAV.

Against the above background, Hyun Jung Koo, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea, and colleagues aimed to evaluate the diagnostic performance of dynamic CT-myocardial perfusion imaging and coronary CT angiography for cardiac allograft vasculopathy.

63 heart transplantation patients underwent combined CT-MPI and CCTA plus invasive coronary angiography (ICA) with intravascular ultrasonography (IVUS) between 2018 and 2021. The median interval between CT-MPI and heart transplantation was 4.3 years.

The researchers calculated peak myocardial blood flow (MBF) of the whole myocardium (MBFglobal) and minimum MBF (MBFmin) among the 16 segments according to the AHA (American Heart Association) model, except the left ventricular apex from CT-MPI.

A qualitative assessment of CCTA was done and the degree of coronary artery stenosis was recorded. CAV diagnosis was done based on both IVUS and ICA (ISHLT criteria). Patients were followed for a median of 2.3 years after CT-MPI and a median time of 5.7 years following transplantation.

The researchers reported the following findings:

• Among the 63 recipients, 55.6% had diagnoses of CAV.
• The median MBFglobal and MBFmin were significantly lower in patients with CAV (128.7 versus 150.4 mL/100 mL/min; and 96.9 versus 122.8 mL/100 mL/min respectively).
• The combined use of coronary artery stenosis on CCTA and MBFmin showed the highest diagnostic performance with an area under the curve of 0.886 (sensitivity: 74.3%, specificity: 96.4%, positive predictive value: 96.3%, and negative predictive value: 75.0%).

"For the detection of cardiac allograft vasculopathy, the combination of CT-MPI and CCTA showed excellent diagnostic performance," the researchers wrote.

"One-stop evaluation of the microvascular components and coronary artery involved in CAV using combined CCTA and CT-MPI may be a potent noninvasive screening method for early CAV detection," they concluded.

Reference:

Ahn, Y., Koo, H. J., Hyun, J., Lee, S. E., Jung, S. H., Park, D., Ahn, J., Kang, D., Park, S., Hwang, H. S., Kang, J., Yang, D. H., & Kim, J. (2023). CT Coronary Angiography and Dynamic CT Myocardial Perfusion for Detection of Cardiac Allograft Vasculopathy. JACC: Cardiovascular Imaging, 16(7), 934-947. https://doi.org/10.1016/j.jcmg.2022.12.031