Optical coherence tomography for characterization of cardiac allograft vasculopathy after heart transplantation (OCTCAV study)

Optical coherence tomographic evaluation of transplant coronary artery vasculopathy with correlation to cellular rejection

BACKGROUND

Cardiac allograft vasculopathy is an accelerated fibroproliferative process that affects the coronary arteries of transplanted hearts. Intracoronary imaging with optical coherence tomography enables detection of subangiographic cardiac allograft vasculopathy.

METHODS AND RESULTS

At the time of routine surveillance coronary angiography, 48 consecutive heart transplant recipients underwent optical coherence tomographic imaging of 1 coronary artery. Imaging findings were compared per rejection history that was graded according to the International Society of Heart and Lung Transplantation classification as none/mild (International Society of Heart and Lung Transplantation 0, 1A/1B, or 2) or high-grade rejection (≥3A). Compared with the none/mild rejection group (37 patients) using Mann-Whitney U test, patients in the high-grade rejection group (11 patients) had a thicker intima in all coronary segments (distal: 0.22 mm [0.09-0.41] versus 0.09 mm [0.06-0.17], P=0.02; middle: 0.35 mm [0.00-0.45] versus 0.14 mm [0.08-0.24], P=0.002; and proximal: 0.34 mm [0.21-0.44] versus 0.15 mm [0.11-0.21], P=0.005) and a higher prevalence of foamy macrophages (distal: 55% versus 9%, P=0.003; middle: 55% versus 22%, P=0.004; and proximal: 44% versus 13%, P=0.05) using χ(2) statistics. Side branches in the high-grade rejection group had smaller lumen diameters and a higher prevalence of intimal thickening (54% versus 36%; P=0.01). Intimal microvessels were also more prevalent in the high-grade rejection group versus the none/mild rejection group (46% versus 11%; P=0.02).

CONCLUSIONS

Coronary optical coherence tomographic evaluation revealed that patients with a history of high-grade cellular rejection, compared with those with none/mild rejection, had more coronary artery intimal thickening with macrophage infiltration, involving all coronary segments and side branches.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT01403142.

Cardiac allograft vasculopathy can be distinguished from donor-transmitted coronary atherosclerosis by optical coherence tomography imaging in a heart transplantation recipient: double layered intimal thickness

Although survival after heart transplantation (HTx) has improved in recent years, cardiac allograft vasculopathy (CAV) is still the leading cause of remote morbidity and mortality in HTx recipients, partly because of difficulty with its diagnosis. In general, routine surveillance for CAV is advocated with coronary angiography accompanied by intravascular ultrasound (IVUS) if necessary. However, these modalities have limitations with respect to low spatial resolution, and sufficient qualitative/quantitative assessment of coronary intima has not been accomplished. Recently, optical coherence tomography (OCT) has emerged as a novel intracoronary imaging technique using an optical analogue of ultrasound with a spatial resolution of 10-20 µm, which is 10 times greater than IVUS. We here experienced a 49-year-old male who received a HTx 3 years ago, and OCT was executed during low molecular weight dextran injection. OCT demonstrated distinct double intimal layers probably consisting of a donor-transmitted atherosclerotic layer and an inner intimal proliferation due to CAV, which was indistinguishable by IVUS and virtual histological analyses. We believe that OCT imaging is not only a new loadstar during treatment of CAV but also a new generation modality for screening for early CAV in HTx recipients.

Evolving concepts and treatment strategies for cardiac allograft vasculopathy

OPINION STATEMENT

The central event in the development of allograft vasculopathy is the inflammatory response to immune-mediated and nonimmune-mediated endothelial damage. This response is characterized by the release of inflammatory cytokines, upregulation of cell-surface adhesion molecules, and subsequent binding of leukocytes. Growth factors stimulate smooth muscle cell proliferation and circulating progenitor cells are recruited to sites of arterial injury leading to neointima formation. Because of its diffuse nature, intravascular ultrasound is more sensitive than angiography for early diagnosis. Proliferation signal inhibitors (PSIs) have the capacity to slow vasculopathy progression by inhibiting smooth muscle cell proliferation, but its side effects profile makes its use as a first line agent difficult. Retransplantation is still the only definitive therapy but is available only in selected cases. The current hope is that immunomodulation at the time of transplant could induce long-term tolerance and graft accommodation, leading to less vasculopathy.