Visceral Vascular Testing:
Review And Update

by Tina Nack Woods, MPE, RVT, RDMS

from the Spring 1998 issue

The broad range of noninvasive visceral vascular examinations and the variations in the "menu" of such services provided at different sites has continued to make the visceral vascular studies section a challenge for the Accreditation Commission as well as the applicant laboratories. Revisions in the self studies and Essentials and Standards of all testing sections of the accreditation application have been implemented on multiple occasions. This has been the result of feedback provided from individual labs, the natural learning curve of all those involved in the accreditation process and changes in reimbursement policy brought about by accreditation itself. As a result, the procedure volume requirements and the number and mix of required case studies for the visceral vascular testing section have changed over the years, adding to the confusion of the complex task of evaluating this diverse group of examinations in an efficacious manner.

Visceral vascular examinations are divided into eight vessel groups in the self study: the mesenteric arterial system, the portal venous system, portosystemic shunts and TIPS, hepatic veins, renal arteries, renal veins, renal transplants and liver transplants. Evaluation of the abdominal aorta and iliac arteries, the inferior vena cava, and iliac veins have been removed from the visceral vascular section (effective 1997). In addition, it is no longer necessary to perform testing in a minimum of three vessel groups. If a laboratory does the majority of its visceral vascular testing in one vessel group, such as renal arteries, they are now eligible to apply for visceral vascular accreditation.

When tabulating procedure volumes, a study is to be listed under one vessel group only, even if multiple vessels are studied. The designated vessel group should be the vessels of chief interest according to the principal indication for the study. Once procedure volumes have been tabulated by vessel group for the sample year you have chosen for the purposes of the accreditation application, the vessel group that is studied with the greatest frequency is considered the "primary" vessel group for the laboratory.

Prior to 1997, a laboratory was required to perform at least 100 primary examinations per year to have their application considered; however, the Standard has been revised to a recommendation that 100 examinations be performed annually. The change in policy is an effort to accommodate low-volume laboratories that provide quality examinations, especially where accreditation is or may be required for reimbursement. Laboratories with annual procedure volumes of less than 100 per year in a given section will be required to submit additional case studies to assure that quality is being maintained and the laboratory is in substantial compliance with the Standards (see table 1.0). These cases will be selected from a time frame determined by the ICAVL; a log or schedule book documenting dates of studies will also be required.

Another change of note in the Standard revision from 1997 is in the visceral vascular techniques section. The requirement that fasting and post-prandial testing be performed for mesenteric arterial evaluation for chronic mesenteric insufficiency has been changed to evaluation in the fasting state only. The Standard now requires laboratories that routinely perform post-prandial studies to document the indications and rationale for post-prandial testing in their self study documents.

The majority of other changes in the visceral vascular standard have been largely for consistency in language and to make the document as understandable and flexible as possible. Of note, a comment has been added in 1997 regarding the potential and unavoidable crossover of the visceral vascular examination into the realm of parenchymal evaluation. The comment is as follows:

"Visceral vascular ultrasound generally requires the evaluation of both the vessel of interest and the organ(s) supplied by that vessel. Therefore a combination of imaging and flow evaluation is required. The vascular examination is not intended to replace a complete medical ultrasound examination of a specific organ system."

Thus the applicant laboratory should keep in mind that high quality gray scale imaging of the organ parenchyma should be considered part of the routine examination. Protocols and diagnostic criteria should list the gray scale images routinely collected and how they are interpreted. The case studies should demonstrate adherence to the stated protocols and criteria. When preparing your application, it is to your advantage to provide high quality hard copy reproductions for your case studies. If possible, get a fresh pair of eyes to review these studies before submitting the application. Hard copy of insufficient quality to allow meaningful review can cause a deferred or delayed decision. The case study images and documents should be sufficient to support the diagnosis presented in the final report to the satisfaction of an outside reviewer with comparable visceral vascular experience to a typical reader in an accredited laboratory.

I hope that the above information will be of use to those currently in the process of accreditation or reaccreditation. While accreditation is an arduous process, it is also an opportunity to submit your laboratory to self and peer review, and almost always results in improvements that allow laboratory personnel to provide patient care at continuously higher levels of quality.

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