Endothelial function: ready for prime time?

The strategic location of the endothelium allows it to detect changes in hemodynamic forces and blood-borne signals, and to respond by releasing a number of autocrine and paracrine substances. The balanced release of these bioactive factors facilitates vascular homeostasis. If disrupted, endothelial cell dysfunction ensues. This predisposes the vessel wall to vasoconstriction, leukocyte adherence, platelet activation, thrombosis, vascular inflammation and atherosclerosis. Given the central role of the endothelium in the development and progression of atherosclerosis, endothelial function testing may serve as a useful biomarker of atherosclerotic disease. The present review highlights the current modalities used in assessing endothelial function, explores how endothelial function may serve as a biomarker for atherosclerosis, comments on the prognostic relevance of endothelial function and describes its use in the clinical setting.     

Computed tomographic colonography: ready for prime time?

Computed tomographic (CT) colonography is a noninvasive method to evaluate the colon and has received considerable attention in the last decade as a colon-imaging tool. The technique has also been proposed as a potential primary colon cancer-screening method in the United States. The accuracy of the technique for the detection of large lesions seems to be high, perhaps in the range of colonoscopy. Overall, the field is rapidly evolving. Available data suggest that CT colonography, although a viable colon cancer screening modality in the United States, is not ready for widespread implementation, largely because of the lack of standards for training and reading and the limited number of skilled readers.     

Arterial stiffness: Is it ready for prime time?

Recent interest in arterial stiffness as a possible new biomarker of cardiovascular (CV) disease has emerged. Arterial stiffness of the large, elastic conduit arteries is considered a risk marker of vascular aging; it leads to widened pulse pressure (PP) and the development of isolated systolic hypertension in the middle-aged and elderly population. However, increased PP is not always a good surrogate for arterial stiffening because of the frequent discrepancy between peripheral brachial and central aortic PP values caused by varying wave reflection activity. Therefore, noninvasive, easily performed methods for more direct measurement of arterial stiffness, such as pulse wave velocity (PWV) and pulse wave analysis (PWA) have been developed for clinical use. This article asks the question: How useful are PWV and PWA, when compared with traditional measurement of blood pressure components, as biomarkers of CV disease?     

Growth hormone therapy for adults: not ready for prime time?

Human growth hormone is now readily available and approved for treatment of the growth hormone deficiency syndrome in adults. However, physicians have been slow to adopt this therapeutic modality. Reasons for skepticism about the use of growth hormone for the growth hormone deficiency syndrome include doubts about whether growth hormone deficiency causes increased morbidity and mortality in patients with hypopituitarism; availability of highly efficacious, easier to use, and less expensive agents for certain aspects of the growth hormone deficiency syndrome, especially cardiovascular disease; and concerns about possible toxicity in adults. Long-term studies in patients receiving appropriate comprehensive management for other hormonal deficiencies and for concomitant abnormalities will be required to convince physicians of the utility and safety of growth hormone replacement therapy.     

Drugs affecting visceral sensitivity: ready for the prime time?

Visceral sensitivity has been recognized over the last decade as a frequent pathophysiological component of functional bowel disorders. Studies in animals and humans have identified numerous neurotransmitters involved in the processing of sensations from the gut to the brain. However, up to now none of them has actually been proven to have a marked clinical efficacy and the benefit comes rather from their action of bowel disturbances. Reproducible tests are lacking to detect visceral hypersensitivity in humans and distension tests are difficult to undertake in a clinical setting. Therefore, abnormal visceral sensitivity may not be regarded as a tool to select IBS patients as candidates for a given treatment.     

Endoscopic ultrasound-guided anastomosis: Is it ready for prime time?

Significant advancements in endoscopic ultrasound (EUS)-guided drainage procedures and EUS-guided anastomosis have recently been described. The described procedures include EUS-guided drainage of pancreatic fluid collections, biliary drainage, pancreatic duct drainage, gallbladder drainage, and gastroenterostomy. These procedures have been made possible with novel devices that can reduce the difficulties of the procedures and potentially reducing the risk of adverse events. The procedures are also becoming standardized, which is essential for dissemination of the techniques. Furthermore, results from randomized studies are becoming available showing definite benefits associated with these procedures. In this paper, we will provide a review on EUS-guided anastomotic procedures.     

CT for assessing ventricular remodeling: Is it ready for prime time?

Reliable assessment of left ventricular size and systolic function has important prognostic and therapeutic implications for patients with heart disease. CT technology is advancing rapidly and can be used for noninvasive assessment of the coronary anatomy. Without additional radiation or contrast, the already acquired image data set can be used for analysis of left ventricular size, mass, and systolic function. In comparison with other noninvasive modalities, multidetector CT has superior spatial resolution but temporal resolution has suffered. Recent advances, including multisegment reconstruction and dual-source scanning, have improved the temporal resolution substantially. MRI is the current gold standard for assessing the left ventricle. Many small comparative studies suggest that CT has good agreement with MRI and that it could potentially replace MRI in some patients, especially those with internal cardiac devices. The use of CT to assess ventricular remodeling is limited by the use of contrast and radiation, but its widespread availability, ease of use, and improved temporal resolution suggest that multidetector CT will have expansive use in the future.