Optical Frequency Domain Imaging Found to Detect More Atherosclerotic Plaques Than Angiography

Optical frequency domain imaging (OFDI) was found to accurately detect and assess angiographically unvisualized atherosclerotic plaques in the left main (LM) arterial wall, according to results from a retrospective clinical study published in the Journal of Interventional Cardiology.

Patients (n=42; mean age, 55.6±16 years; 61.9% men; mean body mass index, 25.9±4.7 kg/m²) who underwent OFDI that included the whole LM and ostia of its bifurcating branches between 2015 and 2018 at the Pitié Salpêtrière University Hospital in Paris, France, were recruited. Images for each region (the proximal, mid, and distal LM and the first 5 mm of the left anterior descending [LAD] and left circumflex [LCX] arteries) were subdivided into 4 quadrants, and the number of artifacts was calculated for each quadrant. An artifact was defined as one of the following: out of the field of view, suboptimal vessel flushing causing blood swirls in the lumen, rapid movement of the artery or imaging catheter, or resulting from incorrect wire position.

In this cohort, 90.5% of patients presented with a myocardial infarction, and 61.9% had single vessel disease.

Plaques were visible on angiography in 48.8% of patients, compared with the ability of OFDI to detect plaques in 76.2% of patients (P =.007). Compared with normal segments, plaques were fibrous (68.7%) or fibrocalcific (31.3%), had greater intima thickness (0.10±0.02 mm vs 0.53±0.22 mm, respectively; P <.001) and had a greater intima to media ratio (1.0±0.17 vs 4.70±2.51 mm, respectively; P <.001).

The overall artifact rate was low (8.9%). The majority of artifacts were caused by out-of-field (45.1%) or residual (44.7%) blood. Suboptimal blood flushing (7.2%) and incorrect wire position (3.0%) were far less likely to result in an artifact. Length of LM was associated with increased rates of artefacts (11.3±4.8 mm vs 7.9±2.8 mm; P =.016) and were correlated with LM diameter (r, 0.34; P =.026).

The majority (18.6%) of artifacts were observed in the proximal LM, with a progressive reduction in their prevalence in more distal regions: mid LM, 5.8%; distal LM, 3.6%; ostial LAD, 2.6%; and ostial LCX, 0.0%.

Limitations of this study include the small sample size and the fact that patients with ostial or severe LM stenosis were excluded, although they were not suitable for OFDI assessment.

”Our study showed that OFDI can accurately evaluate the LM and detect and assess angiographically unvisualized atherosclerotic plaques, providing accurate assessment of >90% of the quadrants of the LM and the ostia of its bifurcation branches,” concluded the study authors.

Reference

Roule V, Rebouh I, Lemaitre A, et al. Evaluation of left main coronary artery using optical frequency domain imaging and its pitfalls. J Interv Cardiol. 2020;4817239. doi:10.1155/2020/4817239