Ventricular Fibrillation During Optical Coherence Tomography/Optical Frequency Domain Imaging - A Large Single-Center Experience

Ventricular Fibrillation during Optical Coherence Tomography

Optical Coherence Tomography (OCT) imaging is a valuable tool for complex coronary interventions. While complications are rare, the occurrence of ventricular arrhythmias during its use is one of the most feared. Unfortunately, the mechanism by which these arrhythmias arise remains unclear. We describe the case of a patient under continuous electrocardiographic (ECG) monitoring who experienced ventricular fibrillation during an OCT procedure. A detailed analysis of the ECG event sequence was performed, from the administration of the contrast medium to the onset of ventricular fibrillation. Utilizing the collected data, we examined potential precipitating factors based on the observed alterations in the electrocardiogram. A comprehensive understanding of the mechanisms underlying these arrhythmias is crucial for the development of preventive measures that avoid such incidents in the future.

Investigations of injection strategies to use heparinized normal saline instead of contrast media for intracoronary optical coherence tomography imaging

BACKGROUND

The benefits of intravascular imaging-guided percutaneous coronary interventions (PCI) are well established. Intravascular imaging guidance improves short- and long-term outcomes, especially in complex PCI. Optical coherence tomography (OCT) has a higher resolution than intravascular ultrasound. However, the usage of OCT is mainly limited by the need to use contrast for flushing injections, which increases the risk of contrast-induced acute kidney injury, especially in patients with underlying chronic kidney disease. The aim of this study was to prove that flushing techniques with normal saline instead of contrast can be used in OCT imaging and can generate high-quality images.

METHODS

This prospective single-center observational study included patients with indications for OCT-guided PCI. For OCT pullbacks, heparinized saline was injected by an automatic pump injector at different rates, and additional extension catheters for selective coronary artery engagement were used at the operator's discretion. Recordings were made using the Ilumien Optis OCT system (Abbott) and the Dragonfly (Abbott) catheter and were analyzed at 1-mm intervals by two operators. Pullbacks were categorized as having optimal, acceptable, or unacceptable imaging quality. A clinically usable run was determined if >75% of the region of interest length was described as having optimal or acceptable imaging quality.

RESULTS

A total of 32 patients were enrolled in the study; 47 different lesions were assessed before and after PCI. In total, 91.5% of runs were described as clinically suitable for use.

CONCLUSION

Heparinized saline injections for OCT imaging are effective in generating good-quality OCT images suitable for clinical use.

Optical coherence tomography in coronary atherosclerosis assessment and intervention

Since optical coherence tomography (OCT) was first performed in humans two decades ago, this imaging modality has been widely adopted in research on coronary atherosclerosis and adopted clinically for the optimization of percutaneous coronary intervention. In the past 10 years, substantial advances have been made in the understanding of in vivo vascular biology using OCT. Identification by OCT of culprit plaque pathology could potentially lead to a major shift in the management of patients with acute coronary syndromes. Detection by OCT of healed coronary plaque has been important in our understanding of the mechanisms involved in plaque destabilization and healing with the rapid progression of atherosclerosis. Accurate detection by OCT of sequelae from percutaneous coronary interventions that might be missed by angiography could improve clinical outcomes. In addition, OCT has become an essential diagnostic modality for myocardial infarction with non-obstructive coronary arteries. Insight into neoatherosclerosis from OCT could improve our understanding of the mechanisms of very late stent thrombosis. The appropriate use of OCT depends on accurate interpretation and understanding of the clinical significance of OCT findings. In this Review, we summarize the state of the art in cardiac OCT and facilitate the uniform use of this modality in coronary atherosclerosis. Contributions have been made by clinicians and investigators worldwide with extensive experience in OCT, with the aim that this document will serve as a standard reference for future research and clinical application.

Effect of contrast medium versus low-molecular-weight dextran for intracoronary optical coherence tomography in renal insufficiency

Low-molecular-weight dextran (LMWD) is considered a safe alternative to contrast media to displace blood during optical coherence tomography (OCT) imaging, but concerns remain. The purpose of this study was to investigate whether using LMWD for OCT protects against kidney injury in patients with renal insufficiency compared with contrast media. We retrospectively identified 474 patients with renal insufficiency (estimated glomerular filtration rate < 60 ml/min/1.73 m²) who underwent OCT during coronary angiography or percutaneous coronary intervention; 110 patients with LMWD plus contrast medium (LMWD group) and 364 patients with contrast medium exclusively (Contrast group). We evaluated differences between the two groups and performed propensity score-matched subgroup comparisons. Compared with the Contrast group, the LMWD group had worse baseline renal function, higher prevalence of diabetes mellitus and percutaneous coronary intervention history, higher C-reactive protein and N-terminal pro B-type natriuretic peptide levels, lower hemoglobin levels, and lower left ventricular ejection fraction. The median total volume of contrast medium in the Contrast group was 230.0 ml vs. 61.8 ml of LMWD in addition to 164.0 ml of contrast medium in the LMWD group. Renal function was consistently impaired in the LMWD group within 5 days, at 1-month, and 1-year follow-up (P < 0.001). Two propensity score-matched analyses adjusted for either total volume used or contrast media volume consistently indicated a trend toward worsening renal function in the LMWD group at the 1-year follow-up. No protective benefit for renal function from using LMWD instead of contrast media for OCT was observed in patients with renal insufficiency.