Aging is a set of processes that alter an individual's life as they age. It affects all body systems, but not necessarily at the same time or to the same extent in any individual. Aging also increases susceptibility for diseases. Understanding and potentially modifying factors that act on age can alter the natural history and lead to delay in the onset of disease. Aging impacts on the vascular tree and alters its capability to adapt. Increasing age is associated with an increase in intimal medial thickness (IMT) and with increasing arterial stiffness. Increasing IMT is directly related to an increased risk for coronary artery disease. The presence of increased stiffness is related to systolic blood pressure and increasing pulse pressure which in turn are related to coronary disease. By understanding and modifying aging processes that affect the arteries, atherosclerosis can be modified by potentially altering age-related changes in blood pressure, body mass and serum lipids. Other modifiable environmental and lifestyle factors are likely to affect the arterial aging process and cardiovascular risk. For example, cardiovascular fitness and physical activity decline with increasing age at a relatively fixed rate, even in the fittest individuals. These declines are likely regulated by the aging nervous system, and are observed in a number of species. Factors that overcome these aging changes may positively impact on fitness and minimize aging in the arterial tree. Environmental and socioeconomic factors are increasingly being identified as a risk for vascular disease, and perhaps differential aging. The causes for these differences are not known. However, differences in depression, stress, anger and coping are being considered as potential mechanisms. Such differences argue for a differential regulation within the nervous system that likely involves the hypothalamus and ventrolateral medulla. Vascular aging has a clear impact on well-being and the development of disease. The observations presented here argue that these changes, while cumulative with age, and caused by a number of different processes that act at molecular, cellular and system levels. The capability of identifying and modifying these processes may in the long-term slow aging in the vascular tree and delay or prevent arterial diseases. Age and aging have major impacts on the vascular and cardiac systems. The processes important for disease development are directly impacted by individual age. Lakatta and Levy (2003) have recently explored the importance of aging on the vascular tree and the heart. This review will consider a few of the points they have raised, and suggest other age-related issues that may be important in altering the internal milieu, thus increasing susceptibility to atherosclerosis and cardiovascular diseases.
Among 206 workers at three companies with abnormal findings for either blood pressure, blood lipid, or blood glucose, carotid ultrasonography revealed intima-media thickening in the common carotid artery (max IMT≥1.1mm) in 8% at age 30-49 years and in 30% at age 50-59 years. The respective prevalence of thickening in the internal carotid artery (max IMT≥1.5mm) was 10% and 39%. The mean of max IMT and the proportion of IMT thickening increased with increases in the number of risk factors. Carotid ultrasonography is thus feasible for health care in middle-aged workers. In 112 workers with hypercholesterolemia, who had a serum total cholesterol level of 220-279 mg/dl in one clerical company, the proportion of ‘mild’ or ‘moderate’ carotid atherosclerosis was 20%. As a consequence of having carried out health guidance at the same time as carotid ultrasonography, the proportion of workers who had continued several action plans for health behavior improvement every six months was 80%. Simultaneous carotid ultrasonography and health guidance was considered to be more effective for health behavior improvement than health guidance alone.
Object. We intended to evaluate the usefulness of intraoperative ultrasound imaging for assistance during neurosurgical operations. Methods. Thirty-four consecutive patients (19 with brain tumor, 9 with subarachnoid hemorrhage, 4 with intracerebral hemorrhage, 2 with hydrocephalus) underwent neurosurgical operations with the assistance of intraoperative ultrasound imaging. A total of 46 operations (removal of tumor in 18 patients, biopsy in one, removal of intracerebral hematoma in 4, ventricular drainage in 16, and ventriculo-peritoneal (VP) shunt in 7) were performed. Two different types of ultrasound machines (General Electric, RT4600 and LOGIQ 500) were used in this series, and their probes were the sector (3.3 and 3.5 MHz) linear (6.7 MHz), and pencil (5 MHz) types. Results. Ventricular drainage and placement of the ventricular tube were easily accomplished under real-time visualization of the ventricles by B-mode imaging. Tumors were clearly demonstrated over the dura mater and then the shortest approach to the tumor could be determined. Arteries and veins around the tumors were detected by color Doppler imaging. Intracerebral hematoma was easily detected and the appropriate site for evacuation could be determined. Conclusion. Intraoperative ultrasound imaging can contribute to the safety and precision of ventricular drainage and VP shunt, and removal of brain tumor and intracerebral hemorrhage.
Between December 2000 and April 2002, we examined the cerebral perfusion of 31 patients with intracerebral hemorrhage (ICH) who underwent stereotaxic hematoma evacuation (SHE). Cerebral perfusion was studied by contrast ultrasonography with pulse inversion harmonic imaging (ICIp), which is more effective than conventional harmonic imaging. The ultrasound instrument was an HDI 5000 and the sector probe was one of the broad-banded type (P4-2). The microbubbled contrast agent was injected into the right median cubital vein. The frame rate was set to trigger images once every 2 cardiac cycles and to record for three minutes. In this way, we were able to obtain ICIp and transfer the data to a personal computer. We analyzed the images using HDILab and obtained the time intensity curves (TIC). Examinations after the operation were performed using the same procedure on the skin at the same location. We found significant differences in the areas under the curves (Tables 1 & 2). These tests indicated improvement of cerebral perfusion in the surrounding area after SHE and also that a better neurological status could be attained using the SHE method for ICH patients.
Levovist has a significant echo-enhancing effect in patients with an inadequate bone window. We evaluated its diagnostic value in transcranial Doppler sonography (TCD), including its ability to assess hemodynamic parameters of intracranial arteries. The 12 studied patients (5 women and 7 men, ranging in age from 62 to 78 y) comprised 7 with intracranial aneurysms (5 non-ruptured, 2 ruptured), 3 with cerebral infarction, 1 with cerebral hematoma and 1 with brain trauma. According to the precontrast imaging quality, patients were assigned to one of two groups: group 1, highly insufficient native Doppler signal on TCD examination (n=7); group 2, satisfactory waveforms detected on TCD (n=4). Levovist was administered intravenously at a concentration of 300 mg/ml with a total dose of 2 ml (administered in 12 s) or 5 ml (in 30 s). Levovist-induced enhancement characteristics of the Doppler frequency spectrum were then analyzed. In group 1, Levovist improved the diagnostic utility of TCD, and increases of Vs, Vm and Vd after a 2-ml bolus injection were 7.4±1.6%, 9.4±1.5% and 13.8±2.6%, respectively. After a 5-ml bolus injection the increases of Vs, Vm and Vd were 12.7±2.1%, 13.8±1.7% and 16.1±1.9%, respectively. Either a 2- or 5-ml bolus injection revealed a significant increase of velocity (p<0.05). In group 2, use of the echo-enhancement agent did not influence the Doppler velocity. The mean duration of clinically useful signal enhancement with a 5-ml bolus injection (250 to 395 s, mean 301 s) was significantly higher than that with a 2-ml bolus injection (120 to 250 s, mean 188 s) (p<0.05). These results indicate that a significant enhancement of flow velocity after Levovist injection was found only in patients with an insufficient acoustic bone window, and no significant change in flow velocity on TCD was detected in patients with a sufficient acoustic bone window.
Transcranial Doppler (TCD) monitoring is now one of the most important monitoring tools during carotid endarterectomy (CEA). We present a case that showed no abnormal findings of TCD during CEA. The patient was a 65-year-old man with diabetes mellitus and hypertension, who presented with transient left-sided weakness. Presence of a right carotid bruit prompted cerebral angiography, which confirmed severe stenosis of thr right internal carotid artery (ICA). The patient underwent a balloon occlusion test of the right ICA before surgery. During the operation, after removing the atheromatous plaque, there was no back-flow from the right ICA, suggesting occlusion of the latter. Removal of the thrombus and urokinase injection were tried, resulting in recanalization of the ICA. During the procedure, no apparent high-intensity transients (HITs) were detected. However, after declamping the right ICA, only an air bubble was detected by TCD. After the operation, the patient showed no neurological deficits. MR confirmed multiple small infarcts in the right parietal lobe. The importance of TCD during CEA is beyond all doubt, but we must be aware that TCD sometimes may not detect ICA occlusion in cases with good collateral circulation.