| Background and objectiveDSA, CTA, MRI, and ultrasonography are considered to be the most common tool for atherosclerotic plaque and artery stenosis whose role in the development of cardiovascular diseases has been emphasized. Before atherosclerotic plaque and artery stenosis, arterial stiffness is also confirmed as a predictor of cardiovascular disease risk. Echo-tracking technique is a new non-invasive ultrasonic device which was developed to characterize the arterial stiffness of medium and large peripheral arteries in2003. First, the sampling gate was set between the intima to media layers of the arterial wall. Then echo-tracking technique was started to record arterial-wall motion. Combined with blood pressure, the common carotid artery stiffness parameters, including stiffness parameter (β), pressure-strain elastic modulus (Ep), arterial compliance (AC), augmentation index (AI) and pulse wave velocity (PWVβ) were computed automatically by the computer system of the ultrasound machine. In recent years, ET has been widely applied in clinical practice as a noninvasive method for the monitoring of carotid arterial stiffness parameters, such as patients with hypertension, diabetes mellitus, end stage renal disease, in elderly subjects, and in the general population. However, the effect of head and neck irradiation on carotid arterial stiffness parameters has not previously been evaluated.Nasopharyngeal carcinoma (NPC) is one of common cancer in china, especially in south of china. The high risk ages are40to60years, and men are more frequently affected. Owing to its special anatomic site and high occurrence of cervical lymph node metastasis, surgical resection was limited. Fortunately, nasopharyngeal carcinoma is highly radiosensitive, and radiotherapy (RT) is the mainstay treatment. But there are a lot of side effects following radiotherapy, such as fatigue, nausea, vomiting, hair loss, dermatitis, atherosclerotic plaque, and artery stenosis. In recent year, along with improvement on radiotherapy technique and the elongation of patients’ longevity, atherosclerotic plaque and artery stenosis in nasopharyngeal carcinoma patients after radiotherapy is more and more common.The aim of this study was to assess differences, if any, in the values of common carotid artery stiffness parameters, determined by echo-etrcking technique, between patients who had received irradiation to the head and neck region for the treatment of nasopharyngeal carcinoma and control subjects. Materials and methods1. Patients dataThe study group consisted of35consecutive patients with head and neck irradiation for nasopharyngeal carcinoma who were referred to the Ultrasound Department for routine evaluation. This group consisted of23men and12women (age range,40-60years; mean:47±4.1years). Fifty control subjects without head and neck surgery,30men and20women, whose ages also ranged from40to60years (mean:48±3.4years) were recruited in this control group. They had similar age, sex distribution, and cardiovascular risk factors with the patients group. People with heart disease, hypertension, hyperlipidemia, carotid artery plaques or carotid stenosis were excluded from this study.2. Ultrasound ExaminationThe examination was performed with a scanner Aloka Prosound SDD-α10, equipped with a linear array10-13MHz transducer. The subjects enrolled into the study were examined in a quiet temperature-controlled room after remaining in a supine position for at least10minutes. Systolic and diastolic blood pressures were measured from the bilateral brachial artery, and the date was entered into the computer system of the ultrasound machine to allow automatic computation of common carotid artery stiffness parameters. Patients were examined with the head slightly elevated and turned to the contralateral side by about30°. At the same time, all the subjects were monitored by simultaneous ECG. In all patients and healthy controls, routine carotid ultrasound studies were performed. The IMT were obtained at a clear longitudinal axis of CCA. Then echo-tracking technique was started to record arterial-wall motion. The sampling gate was set between intima to media the inner layers of the arterial wall at the point1to2cm distal from the carotid bulb. The operator kept their arms motionless to obtain more than5consecutive and stable waveforms. Then the common carotid artery stiffness parameters, includingβ, Ep, AC, AI and PWVβ were computed automatically by the computer system of the ultrasound machine. The stiffness parameters and IMT of bilateral common carotid artery were measured, and the average value was recorded.Results1. Using t test, no significant differences(P=0.47>0.05) for the ages were found between patients with nasopharyngeal carcinoma after radiotherapy and normal control groups.2. At gray-scale image, the common carotid artery wall of all subjects was smooth with a normal lumen. The IMT in patients group was (0.69±0.07) mm, in the control group was (0.57±0.06) mm, P<0.05。3. In the patients group, the (3, Ep and PWVβ values increased significantly (9.6±3.2,132.3±47.4KPa, and7.03±1.29m/sec) compared to the control group (8.1±1.6,107.9±25.8KPa, and6.45±0.85m/sec, P<0.05.4. The AC of nasopharyngeal carcinoma patients after radiotherapy was decreased compared to the control group, P<0.05.5. There was no significant different in AI between patients with nasopharyngeal carcinoma after radiotherapy and normal adults, P>0.05.6. A good correlation was observed betweenβ,Ep, AC and IMT, with r=0.512, r=0.483, r=-0.713, respectively.ConclusionsEcho-tracking technique was a feasibility way to assess of the carotid elasticity in patients with nasopharyngeal carcinoma after radiotherapy. This study demonstrated the carotid elasticity of in patients with nasopharyngeal carcinoma after radiotherapy was significantly decreased. This could be used as a guide for clinical prevention and treatment. Objective. To assess the wall elasticity of the common carotid artery using echo-tracking in patients with nasopharyngeal carcinoma after radiotherapy and to compare these findings with results of control subjects. Methods. Thirty five patients with head and neck irradiation for the treatment of nasopharyngeal carcinoma and fifty control subjects matched for sex, age, body mass index, and other factors (i.e., hypertension, hypercholesterolemia, diabetes, and cigarette smoking) were examined. All the subjects were40-60years old, and people with carotid artery plaques, carotid stenosis or surgery of head and neck were excluded from this study. E-Tracking technology was performed to follow the movement tracks of the common carotid arterial wall, and the following parameters were assessed simultaneously: intima-medial thickness (IMT), stiffness parameter (β), elastic coefficient (Ep), compliance (AC), augmentation index (AI) and pulse wave velocity (PWVβ). Result The IMT in patients group was (0.69±0.07) mm, in the control group was (0.57±0.06) mm, with P<0.05. The values of P, Ep and PWV(3in patients with nasopharyngeal carcinoma after radiotherapy increased significantly (9.6±3.2,132.3±47.4KPa and7.03±1.29m/s) compared to those in normal adults (8.1±1.6,107.9±25.8KPa, and6.45±0.85m/s; P<0.05), while the values of AC (0.71±0.31mm2/KPa) were lower than that in normal adults (0.87±0.42mm2/KPa; P<0.05). There was no significant different in AI between patients with nasopharyngeal carcinoma after radiotherapy (10.88±13.69%) and normal adults (7.08±18.59%; P>0.05). A good correlation was observed between β, Ep, AC and IMT, with r=0.512, r=0.483, r=-0.713, respectively. Conclusions. Echo-tracking technique was a feasibility way to assess of the carotid elasticity in patients with nasopharyngeal carcinoma after radiotherapy. The study demonstrated there is a measurable, statistically significant difference in IMT and stiffness parameters of common carotid arterial after head and neck irradiation for nasopharyngeal carcinoma. This could be used as a guide for clinical prevention and treatment. |
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