Arterial stiffness characterization of patients with different ACS-causing plaque morphologies quantified by optical coherence tomography
Authors: Anwari E , Abdelwahed Y S , Seppelt C , Meteva D , Gerhardt T , Musfeldt J , Sieronski L , Kraenkel N , Seegers L M , Landmesser U , Leistner D M 
Published: October 2024

Abstract

Background
Optical coherence tomography (OCT) has refined acute coronary syndrome (ACS)-management by enabling in-depth characterization of culprit lesions. Differentiating between plaques with ruptured (RFC) and intact fibrous cap (IFC) has shaped clinical decision making. However, the systemic vascular changes associated with different plaque morphologies remain unexplored.

Purpose
To investigate arterial stiffness among different ACS-causing plaque morphologies (RFC vs. IFC) and its prognostic value post-ACS.

Methods
We conducted a secondary analysis of a prospective registry study, including patients who underwent OCT-characterization of the ACS-causing culprit lesion and received arterial stiffness assessment 90 days post-index event. The association between arterial stiffness parameters, such as pulse wave velocity (PWV), aortic pulse pressure (APP), heart rate-corrected augmentation index (AIx@75) and plaque morphologies was assessed using logistic regression, adjusted for age, sex, hypertension, presence of diabetes mellitus, smoking status, LDL-C and discharge medications (ACE-inhibitors/ARBs, beta blockers, calcium-channel blockers and diuretics). A multiparameter model additionally included intima-media-thickness and all arterial stiffness metrics. Cox regression, further adjusted for stroke history, prior percutaneous coronary intervention or stable coronary artery disease and Killip class, evaluated the link between arterial stiffness parameters and major adverse cardiovascular events plus (MACE+).

Results
In total, 110 patients with arterial stiffness and OCT data were included. Of these, 78 (70.9%) patients had RFC- and 32 (29.1%) IFC-ACS. The median age was 61.5 years and 80.0% of patients were male. Patients with RFC- had significantly higher PWV (8.35 vs. 7.50 m/s, p=0.015) compared to IFC-ACS. Both groups received similar regimens of antihypertensive, diuretic and lipid-lowering pharmacological therapy at discharge (p&gt;0.1). After multivariable adjustment, increased PWV (4th Quartile [Q4] vs. 1st Quartile [Q1] Adjusted Hazard Ratio [aHR]: 1.38 [95% Confidence Interval (CI) 1.02-1.88], p=0.043) was associated with RFC- while high APP was significantly associated with IFC-ACS as the underlying plaque morphology (Q4 vs. Q1 aHR: 0.65 [95% CI 0.48-0.87], p=0.005) (Figure 1).
Furthermore, per one-unit increment in APP we observed a 10% increase in risk for MACE+ in patients with RFC-ACS (aHR: 1.10 [95% CI 1.02-1.19], p=0.016) but not IFC-ACS (aHR: 0.95 [95% CI 0.82-1.11], p=0.54). No risk modification with increases in PWV and AIx@75 were observed, regardless of underlying plaque pathology (p&gt;0.05).

Conclusion
There are distinct differences in arterial stiffness between patients with RFC- and IFC-ACS. These results underscore the value of a patient-specific approach that integrates invasive and non-invasive vascular characterization for identifying high-risk individuals and guiding therapy to enhance clinical outcomes.