By James B. Williams, MD
Years ago, the principle method to visualize the size, course, and blood vessel wall characteristics was with the combination of fluoroscopy and intravascular contrast. While allowing precise characterization of the nature and location of obstruction and other abnormalities of blood vessels within the body, they both (either alone or in combination), pose some risk to the patient, either to the kidneys (contrast, or dye), or through irradiation to the patient as a whole (fluoroscopy).
The perfection and wide acceptance of minimally invasive techniques to treat blood vessel disease (angioplasty, stenting, and atherectomy), while allowing less discomfort and quicker recovery, have increased the quantity of both irradiation and contrast to which a vascular patient is exposed in his life time. Further evolution of minimally invasive technology has allowed widespread use of ultrasound both along the surface of the limb or body being treated, as well as catheter-based, or intravascular, ultrasound, which may be introduced within a blood vessel to determine vessel size, direction of blood flow, characteristic of obstruction (hard, soft, or calcified) or even the length of obstruction. The significant advantage of ultrasound, both topically, and intravascularly, is that it carries no risk to the patient or limb being studied, while decreasing the amount of dye and or irradiation use on the patient.
The major applications of topical or surface ultrasound is that it allows visualization and blood flow characteristics, as well as the relationship of the vessels being studied to each other, depth from the surface, and adequacy of flow. This allows precise placement of local anesthesia and access or puncture of the vessel under direct observation, thus allowing greater comfort and far fewer complications for the patient undergoing percutaneous (needle puncture) vessel entry for angioplasty, stenting, and the like. This is used routinely in our office for entry from all sites.
The intravascular ultrasound image, when combined with fluoroscopy, can pinpoint the location and extent of obstruction within the blood vessel. This can be done without the use of any contrast whatsoever, if the operator is very experienced. See Picture 3.
Intravascular ultrasound also allows precise measurement of diameters, which is important for balloon and stent size used in treatment. It can also tell us if a stent is fully opened.
These two modalities are used routinely in our practice. This has allowed over 90 percent of our procedures to be done from the foot, not the groin, and has cut the use of contrast (toxic to the kidney) by as much as 65-80 percent, which is very important in renal-compromised patients. This allows more and more to be accomplished safely in the office-based setting.
For more information please contact James B. Williams, M.D. at Cardiac Thoracic & Endovascular Therapies, S.C. 309-680-5000,
2420 W. Nebraska Avenue, Peoria, www.cvendo.com.