Title
A complex percutaneous coronary intervention guided by optical coherence tomography with heparinized saline
Introduction
Optical Coherence Tomography (OCT) is an intravascular imaging tool to optimize coronary revascularization, but it utilizes light-based technology most commonly requiring iodinated contrast to clear blood for image acquisition. Because of the potential increased contrast use associated with OCT, there is increased risk of renal impairment.
Clinical Case
The patient is an 88-year-old man with atrial fibrillation, ischemic cardiomyopathy, coronary artery disease status post coronary artery bypass graft, diabetes mellitus, chronic kidney disease stage 3 baseline creatinine of 1.8-2.2 mg/dL, essential hypertension, ventricular tachycardia status post ablation, and heart failure with reduced ejection fraction status post biventricular implantable cardioverter defibrillator, presenting to the hospital with a non-ST elevation myocardial infarction with peak troponin of 5.530 ng/mL. His coronary anatomy included a widely patent left internal mammary artery (LIMA) to left anterior descending artery (LAD) bypass and prior stenting to the proximal to mid right coronary artery (RCA), ostial-proximal left circumflex (LCx), proximal to mid second obtuse marginal (OM), and ostial to proximal ramus intermedius artery (ramus). Echocardiography showed a reduced left ventricular ejection fraction of 28%, decreased from 38%. On the day of coronary angiography, his creatinine was elevated at 2.5 mg/dL. We performed a low contrast angiogram study via right radial artery access, which revealed severe multi-vessel disease with in-stent restenosis (ISR). In the RCA, OCT imaging was obtained with automatic pullback and heparinized saline injections using a 30 mL syringe for high-intensity injections. In this case, OCT allowed measurements of the length of severe in-stent restenosis in the RCA to determine appropriate stent length. Post PCI OCT imaging demonstrated excellent stent expansion and apposition. In the LCx, using heparinized saline injection as flushing media, imaging demonstrated severe ISR in the ostial to proximal LCx and proximal to mid second OM followed by complete in-stent occlusion distally. In addition, pre-PCI OCT showed neoatherosclerosis with concentric thick calcification. Therefore, coronary intravascular lithotripsy was performed, followed by stenting. At the conclusion of the procedure, a total of 10 mL of iodine contrast was administered. OCT was performed during the case with only heparinized saline injections as flushing media. Upon follow up, the patient did not have any evidence of contrast-induced nephropathy with subsequent creatinine of 2.2 mg/dL.
Discussion
We present a case utilizing heparinized saline injections during OCT for successful complex PCI optimization. In our case, the potential for contrast-induced acute kidney injury was of particular concern because of his advanced baseline kidney disease, multiple other comorbidities, and complexity of his multivessel disease. Using saline as the flushing medium provided excellent imaging quality and feasibility to complete revascularization. For his several ISR lesions requiring serial balloon inflations and complex interventions such as lithotripsy, OCT was key in pre-stent planning and obtaining optimal results, and saline was successfully employed for a low-contrast study while still maintaining quality to optimize coronary revascularization. Saline may be used as a contrast saving alternative, particularly for patients with severe renal insufficiency.