Comparison of Optical Coherence Tomography (OCT) and Intravascular Ultrasound (IVUS) for the early diagnosis of cardiac allograft vasculopathy in heart transplant patients

Introduction: Cardiac Allograft Vasculopathy (CAV) is one of the leading causes of death after cardiac transplantation. IntraVascular Ultrasound (IVUS) measures the increase in intima-media thickness (IMT) observed in CAV and is more sensitive for diagnosis of CAV than coronary angiography. Optical Coherence Tomography (OCT), a new intracoronary imaging technique, allows more precise measurement of IMT as compared to IVUS. Objective: Demonstrate that OCT is superior to IVUS for CAV detection in heart transplant patients. Methods: Comparison of OCT and IVUS in heart transplant patients with or without angiographic CAV, performed during their systematic follow-up coronary angiography. Results: Among ten heart transplant patients included with a median age of 53.5±12 years, 4 had angiographically significant CAV. No major adverse cardiac events occurred during the procedure. Twenty-two coronary arteries, divided into 105 segments, were analysed. IMT measured by IVUS and OCT was comparable (limits of agreement [-0.167 – 0.139]). The 4 patients with angiographic CAV had a thicker IMT than healthy patients as defined by IVUS (0.42±0.16 mm et 0.24±0.10 mm respectively, p < 0.001), and by OCT (0.41±0.16 mm and 0.27±0.12, p < 0.001). Only OCT allowed for separate measurement of intima and media. Intimal thickness was significantly increased in patients with CAV (0.28±0.15 mm vs. 0.16±0.09 mm, p < 0.001). Conclusion: OCT and IVUS are both reliable to measure IMT. However, only OCT can evaluate intimal thickening, the key feature of beginning CAV. OCT is therefore a promising tool in the early detection of CAV and may guide adjustment of immunosuppressive treatment aimed at reducing CAV progression.