Optical Coherence Tomography(OCT) is am emerging new technology of intravascular imaging, which uses reflected near-infrared ray instead of reflected ultrasound to image biological tissues, and has important application value in the diagnosis and treatment of coronary heart disease. However, the major drawback of OCT operations is that it requires injection of contrast agent. Excessive contrast agent can increase the risk of contrast induced nephropathy. It is likely that non-contrast agent(such as low molecular weight Dextran) replace contrast agent to flush the blood for OCT imaging.
Coronary angiography has always been considered as the "gold standard" for diagnosing coronary heart disease and evaluating coronary stenosis. Using the principles of fluoroscopy and angiography images, angiography is achieved by filling with contrast agents to observe whether the intraluminal contour is abnormal, thereby indirectly reflecting whether there are intraluminal lesions, but it cannot display the shape, nature and wall structure of intraluminal lesions and plaques, so coronary angiography imaging has obvious limitations. With the advent of new intravascular imaging modalities, especially intravascular ultrasound (IVUS) and intravascular optical coherence tomography (OCT), coronary assessment has been greatly improved.
The biggest disadvantage of current OCT procedures is the application of non-ionic or isotonic contrast agents, which are expensive and may lead to complications such as allergic reactions, contrast induced nephropathy (CIN) and deterioration of cardiac function, limiting the clinical application of OCT in coronary artery disease. Low molecular weight Dextran (LMWD) is inexpensive and less toxic, and can be used as a flushing medium instead of contrast agents. The existing research data suggest that LMWD-OCT has good safety and efficacy in coronary heart disease intravascular imaging. But relevant studies are limited, the sample size is small, and the long-term effects of this procedure on major adverse cardiovascular events and changes in renal function have not been observed. In addition, whether LMWD-OCT can prevent the deterioration of renal function in patients with high risk factors for CIN is still controversial. Therefore, the feasibility of LMWD to replace contrast agent to achieve coronary OCT imaging still needs to be verified by a large number of prospective studies. The results of the study will provide a new option for intravascular imaging in patients with coronary heart disease complicated by renal insufficiency.