Elsevier

International Journal of Cardiology

Volume 343, 15 November 2021, Pages 171-179
International Journal of Cardiology

Coronary plaque and clinical characteristics of South Asian (Indian) patients with acute coronary syndromes: An optical coherence tomography study

https://doi.org/10.1016/j.ijcard.2021.08.048Get rights and content

Highlights

  • South Asians with ACS were younger and more frequently presented with STEMI.

  • Plaque erosion was the predominant pathology for ACS in South Asians.

  • South Asian patients had more features of plaque vulnerability in culprit lesions.

Abstract

Background

South Asians, and Indians in particular, are known to have a higher incidence of premature atherosclerosis and acute coronary syndromes (ACS) with worse clinical outcomes, compared to populations with different ethnic backgrounds. However, the underlying pathobiology accounting for these differences has not been fully elucidated.

Methods

ACS patients who had culprit lesion optical coherence tomography (OCT) imaging were enrolled. Culprit plaque characteristics were evaluated using OCT.

Results

Among 1315 patients, 100 were South Asian, 1009 were East Asian, and 206 were White. South Asian patients were younger (South Asians vs. East Asians vs. Whites: 51.6 ± 13.4 vs. 65.4 ± 11.9 vs. 62.7 ± 11.7; p < 0.001) and more frequently presented with ST-segment elevation myocardial infarction (STEMI) (77.0% vs. 56.4% vs. 35.4%; p < 0.001). On OCT analysis after propensity group matching, plaque erosion was more frequent (57.0% vs. 38.0% vs. 50.0%; p = 0.003), the lipid index was significantly greater (2281.6 [1570.8–3160.6] vs. 1624.3 [940.9–2352.4] vs. 1303.8 [1090.0–1757.7]; p < 0.001), and the prevalence of layered plaque was significantly higher in the South Asian group than in the other two groups (52.0% vs. 30.0% vs. 34.0%; p = 0.003).

Conclusions

Compared to East Asians and Whites, South Asians with ACS were younger and more frequently presented with STEMI. Plaque erosion was the predominant pathology for ACS in South Asians and their culprit lesions had more features of plaque vulnerability.

Clinical Trial Registration: http://www.clinicaltrials.gov, NCT03479723

Introduction

Acute coronary syndrome (ACS) is one of the most frequent causes of hospitalization, morbidity, and mortality worldwide [1]. South Asians are known to have a higher incidence of premature atherosclerosis including ACS with worse outcomes, as compared to populations of other ethnic backgrounds. [[2], [3], [4]]. India has the largest population among South Asian countries and it is estimated that large numbers of patients are suffering from coronary artery disease (CAD) [5]. The number of patients with atherosclerotic disease is dramatically increasing in South Asia and this region is expected to have more patients with atherosclerotic disease than any other parts of the world in the near future [2,6]. In addition, ACS occurs at a younger age and is associated with higher mortality in the South Asian population [4,6,7]. The high rate of ACS is often explained by the higher prevalence of conventional atherosclerotic risk factors, such as diabetes mellitus (DM) or dyslipidemia, at a younger age [8,9]. Genetic factors have also been reported to affect the prevalence of ACS in the South Asian population [6]. However, despite these observations, data on coronary plaque characteristics in South Asian patients are limited.

Recently, the concept of “vulnerable plaque” is gaining attention. Vulnerable plaque is a plaque at higher risk for future disruption leading to occlusive thrombosis [10]. Thin-cap fibroatheroma (TCFA), macrophages, cholesterol crystal, and microvessels identified by optical coherence tomography (OCT) are considered features of plaque vulnerability [11,12].

This study was conducted to evaluate culprit plaque characteristics in Indian patients with ACS as compared to those in other ethnic populations (East Asian and White) using OCT.

Section snippets

Study population

The study population was from the “Identification of Predictors for Coronary Plaque Erosion in Patients with Acute Coronary Syndrome” study (NCT03479723). This was a multicenter cross-sectional international collaborative study, and approval was obtained from the institutional review board at each participating site [13]. Patients with ACS who had OCT imaging of their culprit lesions were enrolled. The diagnosis of ACS included ST-segment elevation myocardial infarction (STEMI) and

Baseline characteristics

Baseline characteristics are shown in Table 1. Among 1315 patients, 100 patients were South Asian (Chennai and Kochi, South India), 1009 were East Asian, and 206 were White. The distributions of patients with different ethnic backgrounds per age group are shown in Fig. 1. Compared to East Asians and Whites, South Asians were significantly younger. STEMI was the predominant type of presentation in the South Asian group (77.0%), whereas NSTE-ACS was the more frequent in the White group (64.6%).

Discussion

To the best of our knowledge, this is the first report on culprit plaque characteristics in South Asian (Indian) patients with ACS using OCT imaging. Our study demonstrated that South Asian patients with ACS, as compared to those with East Asian and White ethnic backgrounds, (1) were younger with a significantly higher rate of STEMI; (2) had plaque erosion as the predominant underlying mechanism of ACS; and (3) had greater plaque burden (greater prevalence of 3 vessel disease and longer lesion

Conclusions

This study demonstrated that South Asian (Indian) patients present with ACS at a younger age and with a higher rate of STEMI as compared to populations with different ethnic backgrounds. In addition, plaque erosion was the predominant underlying pathology for ACS in South Asian patients. Moreover, South Asian patients had greater features of plaque vulnerability in the culprit lesion, compared to the other ethnic groups.

Source of funding

Dr. Jang's research was supported by Mr. and Mrs. Allan and Gill Gray, and Mr. and Mrs. Michael and Kathryn Park. They had no role in the design or conduct of this research.

Disclosures

Dr. Jang has received educational grant support from Abbott Vascular and a consulting fee from Svelte Medical Systems and Mitobridge Inc. All other authors have no relationships relevant to the contents of this paper to disclose.

Author statement

Ik-Kyung Jang had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Acknowledgments

None.

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