Prevalence of Calcified Coronary Plaque burden in Thais

Abstract

OBJECTIVES: Although quantification of calcified coronary artery plaque burden by computerized tomography scan (coronary artery calcium score, CACS or CAC) has been validated in western populations as a tool to predict future cardiovascular events, its role in cardiovascular disease (CVD) risk assessment remains to be established in Thais. A 10-yr prospective study in asymptomatic Thais with zero CACS has shown a rate of four times higher in CVD events compared with a report on western subjects. In addition, the mean CACS in patients with acute coronary syndrome (ACS) or stroke was quite low, less than 50 AU. This suggests that plaque calcification may have unique drivers and predictive value in Thais. To explore this, we studied the distribution of calcified coronary plaque among male and female Thais of different ages, and with or without history of CVD.

MATERIALS AND METHODS: We retrospectively retrieved CACS (Agaston-130 method) results of a total of 4,104 Thai patients (men 62%, median age 61 years, range 30-96 years) who underwent CACS screening between 2012 and 2021, from eight Bangkok Dusit Medical Service (BDMS) chain hospitals. Median and percentile of CACS were calculated in each age range of both genders. Patients were divided in two groups, those with and those without CVD, by use of diagnostic ICD code (I20-25 for coronary artery disease and I63-69 for cerebrovascular disease). Additionally, CACS results in subjects without prior CVD were compared with those published for asymptomatic US and Korean populations.

RESULTS: Overall, CACS scores were significantly higher in Thai men than Thai women in the same age range, with significant CAC detected ten years earlier, beginning at age of 40 years. There were 1,764 cases among those who had prior diagnosis of CVD (CAD 85.5%, stroke 15.5%), and these subjects were significantly older, with more males, and had higher CACS severity in comparison with those without CVD (CAC = 0: 14.8% vs 40.0%, CAC > 0: 85.2% vs 60.0%, respectively; p < 0.001). In unmatched comparisons between asymptomatic populations, absolute CACS severity (>100 AU) was highest among US subjects (23.7%), followed by Thais (14.9%) and then Koreans (11.6%). On the other hand, zero CACS was highest in Koreans (47.5%), followed by Thais (40%), and lowest in US cases (13.8%). In unmatched comparisons with results from a pooled analysis of CAC studies involving 134,336 Western subjects and 33,488 Asians, Thai men had higher CACS percentiles of 50 and 75 than those of Asians but lower than those of western men. For Thai women, the p-50 and p-75were higher than those of Asians butclose to that of Western subjects and even higher after age of 65. However, the 90th percentile in Thai men and women was closer to that of the western group and highest among Thai women older than 65 years.

CONCLUSION: Our cross-sectional data support CVD prediction by CACS in Thais, with the higher CACS detected, the higher the likelihood of having CVD. However, the lesser severity of CACS and higher proportion of zero CACS in Thai men in comparison with asymptomatic US subjects suggest the existence of differences between ethnic groups and the need for local CVD screening and prevention guidelines.