Abnormal Glucose Regulation Is Associated With Lipid-Rich Coronary Plaque: Relationship to Insulin Resistance

Abnormal Glucose Regulation Is Associated With Lipid-Rich Coronary Plaque

Tetsuya Amano, Tatsuaki Matsubara, Tadayuki Uetani, Michio Nanki, Nobuyuki Marui, Masataka Kato, Tomohiro Yoshida, Kosuke Arai, Kiminobu Yokoi, Hirohiko Ando, Soichiro Kumagai, Hideki Ishii, Hideo Izawa, Nigishi Hotta, Toyoaki Murohara

Conventional and integrated backscatter intravascular ultrasound was used to show that impaired glucose regulation (IGR) as well as diabetes mellitus (DM) is associated with coronary plaque having increased lipid content. In 165 patients (83 with frank DM, 44 with IGR, and 38 normal control patients), the DM and the IGR groups showed an increase in percent lipid volume (36 ± 14% and 37 ± 13% vs. 29 ± 14%, p = 0.02) and a decrease in percent fibrous volume (59 ± 11% and 58 ± 11% vs. 64 ± 11%, p = 0.03). The lipid-rich plaque rate was associated with increasing insulin resistance (p = 0.008). This article provides imaging evidence showing that coronary lesions in patients with abnormal glucose regulation are more lipid rich (with the potential for plaque instability) even before frank DM is identified.

Objectives

This study sought to determine lipid and fibrous volume of coronary atherosclerotic plaques in subjects with abnormal glucose regulation (AGR) by integrated backscatter (IB) intravascular ultrasound (IVUS) during percutaneous coronary intervention.

Background

Abnormal glucose regulation, including impaired glucose regulation (IGR) and diabetes mellitus (DM), has emerged as an important determinant of cardiovascular risk. We hypothesized that AGR would be associated with coronary plaque instability.

Methods

Conventional intravascular ultrasound and IB-IVUS using a 40-MHz (motorized pullback 1 mm/s) intravascular catheter was performed in 172 consecutive patients. The percentage of fibrous area and the percentage of lipid area were automatically calculated by IB-IVUS. Three-dimensional analysis of IB-IVUS images was performed to determine the percentage of lipid volume (%LV) and fibrous volume (%FV). Following the World Health Organization criteria, the subjects were classified into the DM group, the IGR group, and the normal glucose regulation group. The cutoff point for the lipid-rich plaque was defined as %LV >44% or %FV <52%, which was the 75th percentile of %LV or the 25th percentile of %FV in this study population. Insulin resistance (IR) was defined as the homeostasis model assessment of insulin resistance (HOMA-IR).

Results

There were no significant differences in the baseline characteristics except for glucometabolic parameters. The conventional IVUS analysis indicated that the DM group had a significantly increased plaque volume (and percent plaque volume). In the IB-IVUS analysis, as compared with the normal glucose regulation group, the DM and the IGR groups showed a significant increase in %LV (36 ± 14% and 37 ± 13% vs. 29 ± 14%, p = 0.02) and a significant decrease in %FV (59 ± 11% and 58 ± 11% vs. 64 ± 11%, p = 0.03). The lipid-rich plaque rate was significantly associated with an increasing HOMA-IR in the tertile (p = 0.008). On logistic regression analysis after adjusting for confounding and coronary risk factors, the DM group (odds ratio 3.52, 95% confidence interval 1.13 to 11.0, p = 0.03) and the IGR group (odds ratio 3.92, 95% confidence interval 1.13 to 13.6, p = 0.03) were significantly associated with the lipid-rich plaque.

Conclusions

Coronary lesions in patients with AGR are associated with more lipid-rich plaque content, which may be related to the increased IR in these patients.