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Keywords:

  • coronary artery disease;
  • intravascular imaging;
  • near-infrared spectroscopy;
  • lipid core plaque;
  • SYNTAX score

Objective

The purpose of this study was to determine if there was a relationship between angiographic lesion complexity and the extent of lipid core plaque (LCP) identified by catheter-based near-infrared spectroscopy (NIRS).

Background

The angiographic complexity of coronary artery disease (CAD) is used to predict outcomes in patients undergoing percutaneous coronary intervention (PCI). The SYNTAX score, an angiographic tool quantifying the complexity of CAD, is associated with PCI outcomes. Recently, a novel catheter-based imaging technique using NIRS can identify LCP, which also is associated with PCI periprocedural myocardial infarction (MI). However, it is unknown whether these events are related to distinct adverse event prone pathobiology, such as a LCP within a complex angiographic lesion. Thus, we hypothesized that LCP identified by NIRS would be associated with high SYNTAX score.

Methods

Seventy-eight patients who underwent coronary angiography and target-vessel NIRS were selected from the Chemometric Observations of Lipid Core Containing Plaques of Interest in Native Coronary Arteries Registry, an industry sponsored registry to collate clinical findings in all patients undergoing NIRS evaluation. A lipid core burden index (LCBI) was obtained from the scan of the proximal 50 mm of the target vessel. Three vessel SYNTAX (total, tSYN) and target single vessel (only NIRS-interrogated vessel) SYNTAX (1vSYN) scores were calculated and compared to LCBI. High LCBI was defined as (>110) and was compared to tertile scores for 1vSYN score (low 0–5, intermediate 6–10, high ≥11) and previously established tertiles for tSYN score (low 0–22, intermediate 23–32, high ≥33).

Results

Patients had mean age of 63 years with prevalence of females (10%), diabetes mellitus (28%), hypertension (88%), and smoking history (72%); 1vSYN and tSYN scores correlated poorly with LCBI [(r2 = 0.25; P = 0.02; n = 78) and (r2 = 0.24; P = 0.04; n = 78), respectively]. Mean LCBI did not differ significantly across all tertiles of 1vSYN or tSYN scores.

Conclusions

Angiographic SYNTAX score only weakly correlated with LCBI. It is of interest as well that high LCBI was also present in cases of low SYNTAX scores. The disparity between the degree of angiographic complexity and the amount of LCP supports postulated mechanisms of the adverse event propensity even in patients who demonstrate low angiographic complexity. Future studies are necessary to address the clinical significance of high LCBI in patients with low-to-intermediate angiographic complexity and their potential for PCI-related complications. © 2012 Wiley Periodicals, Inc.