Plaque vulnerability assessed by optical coherence tomography and longitudinal physiological deterioration in intermediate coronary stenosis

Background

Optical coherence tomography (OCT) enables detailed characterisation of plaque morphology, including features of plaque vulnerability. However, whether anatomical vulnerability is associated with subsequent physiological deterioration remains uncertain.

Purpose

To investigate the association between baseline OCT-derived plaque vulnerability and subsequent fractional flow reserve (FFR) deterioration in intermediate coronary stenosis.

Methods

We analysed lesions from a prospective multicentre registry of patients with angiographically intermediate coronary lesions (40–70% diameter stenosis) who underwent baseline OCT and FFR assessment, with repeat FFR evaluation at 2 years. Plaque vulnerability features were defined as thin-cap fibroatheroma, macrophage accumulation, microvessels, and cholesterol crystals. Vulnerability burden was calculated as the number of features present (range 0–4). FFR deterioration was defined as a decrease in FFR ≥0.05 from baseline. Relative minimal lumen area (MLA) was calculated as MLA divided by the mean of proximal and distal reference lumen areas. Multivariable logistic regression using a generalised estimating equation approach was performed to evaluate independent predictors of FFR deterioration, including vulnerability burden, relative MLA and lesion length, with additional adjustment for age, hypertension, and diabetes mellitus.

Results

A total of 151 lesions were analysed. Baseline FFR was 0.917 ± 0.065 and follow-up FFR was 0.913 ± 0.079, corresponding to a mean change of −0.004 ± 0.062. FFR deterioration occurred in 20 lesions (13.2%). Among these lesions, mean change in FFR was −0.114 ± 0.079 compared with 0.013 ± 0.036 in lesions without deterioration.

Vulnerability burden was independently associated with FFR deterioration (adjusted odds ratio (OR) 1.64 per 1-feature increase, 95% confidence interval (CI) 1.04–2.58; p=0.032). Relative MLA (OR 1.14 per 0.1 increase, 95% CI 0.84–1.56; p=0.407) and lesion length (OR 1.03 per 1 mm increase, 95% CI 0.98–1.08; p=0.233) were not independently associated.

The predicted probability of FFR deterioration increased progressively from 3.4% in lesions without vulnerable features to 20.2% in lesions with four features. Among individual features, thin-cap fibroatheroma showed the strongest trend (OR 3.46, 95% CI 0.80–15.04; p=0.098).

Conclusion

In intermediate coronary stenosis, baseline OCT-derived plaque vulnerability was independently associated with subsequent physiological deterioration at 2 years. These findings suggest that OCT-defined plaque vulnerability may provide prognostic information regarding subsequent physiological deterioration.Multivariable predictors of FFR deteriorationFor image description, please refer to the figure legend and surrounding text.FFR deterioration by vulnerability burdenFor image description, please refer to the figure legend and surrounding text.