LAUSR

Evaluation of carotid artery function is of paramount importance in patients with high cardiovascular risk. Mechanical properties and hemodynamic function can be evaluated noninvasively by pulse wave analysis, either by hand-held tonometry probe or by photoplethysmography. Ultrasound is also very useful because it can assess both the arterial wall thickness (carotid intima-media thickness—CIMT), as well as the presence of atherosclerotic plaques and it can also assess blood flow velocities. The pulse wave is influenced by geometric and elastic properties of the arterial wall, and it is proportional to arterial stiffness. Arterial distensibility (a measure of the arterial ability to expand and contract with pulse wave propagation) and compliance are both related to the elastic properties of the arterial wall. This pulse wave is influenced by structural and functional vascular changes that occur as a consequence of atherosclerosis and arterial stiffness. Several risk factors, such as glucose, lipids, metabolic syndrome, smoking and stress can induce inflammation and oxidative stress in the arterial wall and endothelial dysfunction that, in association with increased sheer stress caused by hypertension, can cause damage and development of atherosclerotic plaques in the arterial wall, with consequent loss of elasticity, increased stiffness and faster pressure waves. Ultrafast ultrasound imaging is a recent technique. It can capture images at a frame rate up to 100 times faster than conventional imaging (typically faster that 1000 frames per second). Instead of the lineper-line focused beam transmission of conventional ultrasound, with ultrasonic plane-wave transmission of divergent waves summed coherently, it is possible to obtain high quality images at high framerate. This new technology has been developed in the last 20 years and it seems to be a promising alternative for early detection of arterial abnormalities, particularly for arterial wall mechanical properties characterization. Modern equipment uses tissue Doppler imaging method and track the pulse wave in the arterial wall, with automatic identification of the beginning and end of systole. The application of carotid ultrafast ultrasound imaging has been extensively studied in Chinese individuals in the last few years. Pulsed wave velocity (PWV) can be measured at two different instants of the cardiac cycle, corresponding to a low distention (before systole—BS) and high distention (end systole—ES). Previous studies showed that with age, there is a significant increase of PWV-ES but PWV-BS remains stable. In this issue of the journal, An et al evaluated carotid PWV by ultrafast ultrasound imaging in a group of diabetic patients (both with and without microangiopathy) and in a control group of 1544 healthy volunteers from the Multicenter Study Group on Normal Values of Color Pulse Wave Velocity in Chinese Han Adults study. They studied 77 patients with Type 2 diabetes, of whom, 45 with microangiopathy. The presence of increased CIMT or plaque was an exclusion criterion. PWV was assessed with the standard procedure at the beginning (PWVBS) and at the end of systole (PWV-ES). As expected, diabetic patients showed significant higher levels of all cardiovascular risk factors, as well as PWV. Patients with microangiopathy had a more abnormal lipid profile and higher PWV compared to patients without microangiopathy. Age and urine microalbumin/creatinine ratio influenced both PWV-BS and ES, body mass index and glycated hemoglobin influences PWV-BS only, and uric acid PWV-ES only. Compared to PWV-BS, PWV-ES is a more sensitive predictor of diabetic microangiopathy, with a cut-off value of 8.27 m/s (sensitivity of 75% and specificity of 82%). These results, suggest that this method can be an early marker of changes in the arterial wall, even before the formation of atherosclerotic plaques. However, we must be aware of several pitfalls. First, the sample size is relatively small and a study with a larger sample is warranted to confirm these findings. Second, mean age of the diabetic group is similar to the control group and also similar between both diabetic groups. However, age span in the diabetic group is very wide, having included patients aged 14–79 years, and we can also question if the younger patient had indeed type 2 diabetes, because it is unusual at this age. As it is already known, reduced elasticity occurs naturally with increasing age. Another important comment is related to the duration of diabetes, with a mean of 4.9 years in all Received: 21 January 2022 Accepted: 22 January 2022