Researchers investigated and compared the histological features of excised carotid plaques
from patients from China and the US

Carotid plaques block the blood supply to the brain. It is often considered a leading cause of stroke. Ethnicity-based characteristics and differences in the plaques are studied to tailor targeted management approaches. In a recently published study in the Chinese Neurosurgical Journal, histological features of carotid plaques from patients of Chinese and North American populations were investigated and compared, reporting distinct histological differences.

Atherosclerotic cerebrovascular disease refers to a condition where plaque builds up in the arteries that supply blood to the brain, leading to reduced flow of oxygen-rich blood. This can cause life-threatening cerebrovascular events, including a stroke. Plaque build-up in the carotid arteries, the pair of blood vessels on each side of the neck that supplies oxygen-rich blood to the brain, face, and head, is often considered a major cause of ischemic stroke. Understanding the pathophysiology of the plaques is the first step towards developing preventive measures.

Stroke is a leading cause of death and serious long-term disability among the Chinese and North American populations. However, there is a significant difference in the pattern of cerebrovascular disease in these two populations. Imaging studies done in the past have reported notable differences in the location and characteristics of stroke-causing plaques between the two populations.

Recently, a team of researchers from China, led by Professor Binbin Sui from Capital Medical University, Beijing, and Dr. Thomas Hatsukami from the University of Washington decided to analyze the histological differences in carotid advanced atherosclerotic plaques excised from patients from these two populations. “Differences in the characteristics of atherosclerotic disease and plaque composition can be linked to different preventive and treatment approaches,” mentioned Prof. Sui, while talking about the main motivation behind the study. The study was published on October 09, 2025, in Volume 11 of the Chinese Neurosurgical Journal.

Carotid endarterectomy is a surgical procedure to remove plaque buildup from the carotid arteries. Specimens from carotid endarterectomy were analyzed for the study. Samples from 75 Chinese patients and 111 US patients were collected and analyzed. Two different histological staining techniques, hematoxylin and eosin staining and Mallory’s trichrome staining, were performed; the resulting images were captured and analyzed. Different components of the plaques, including lipid pools, necrotic cores or the core of the plaque, and calcification, were compared.

The minimum lumen diameter, the inside space of the tubular carotid artery, was significantly smaller in the Chinese group compared to the US group, which translated into a more severe stenosis—narrowing of the artery. The total wall volume of the atherosclerotic plaque, or the plaque burden, was also larger in the Chinese population.

There was also a distinct difference in the morphology of the plaques between the two groups. Chinese plaques had a more homogeneous morphology than the US plaques. However, the complexity of the plaques collected from North American patients was more prominent, due to the presence of an admixture of different components. Large regions of necrosis, increased calcification, thrombosis, and haemorrhage added to the intricacy of the plaques from the US group. Intraplaque hemorrhage (IPH) is a nontraumatic bleeding that occurs within the brain's functional tissue, known as the brain parenchyma. Evidence of old and new IPH can be observed during histological investigations. The samples from Chinese patients had more recent IPH and less late IPH. Fibrous cap disruption, referring to the breakdown of the protective fibrous cap over an atherosclerotic plaque, was also less frequent in samples from Chinese patients. Lipid-filled deposits of cholesterol or xanthomas were also more prevalent in the Chinese samples, along with a uniform extracellular matrix. The Chinese plaques clearly showed fewer features of advanced atherosclerosis than the US plaques.

There is a clear discrepancy in the histology of plaques collected from Chinese and US samples. This indicates that the pathophysiology of atherosclerotic cerebrovascular disease differs significantly between the two groups. “Our findings show that variations in plaque composition can lead to fundamentally distinct lesions across populations on different continents. This can be considered while planning treatment or preventive measures for cardiovascular events,” mentioned Dr. Hatsukami.

Further comparative studies can help in understand the differences in plaque morphologies between the two populations. Comprehending these variations could facilitate improved risk evaluation and therapy customization for these two populations.