Pioneering Research Shows Less Invasive Technique Should Be Standard for Both Mild and Severe PVD
Nov 18, 2002
A new study by doctors at the NewYork-Presbyterian Hospital Weill Cornell Medical Center shows that the Center's unique diagnostic technology of magnetic resonance angiography (MRA) is the equal of the traditional technique of x-ray angiography in helping physicians plan treatment for patients with peripheral vascular disease (PVD). MRA, which is much less invasive than x-ray angiography, can now be considered as the appropriate and standard diagnostic technique not only for mild forms of PVD but for severe forms as well.
The new study, recently published in the journal Radiology, is the first to show that MRA is useful in guiding the planning of treatment for severe as well as mild PVD. PVD, which afflicts many elderly people, involves a narrowing or obstruction of arteries in the lower body, particularly the legs or feet. In its mildest form, it can lead to pain in walking and is called claudication. In its more severe form, it can lead to pain in the feet at rest as well as foot gangrene and ulcerations.
Magnetic resonance angiography has been developed under the leadership of Dr. Martin Prince, Director of Magnetic Resonance Imaging at NewYork Weill Cornell Medical Center and Professor of Radiology at Weill Cornell Medical College. MRA is a much simpler procedure than x-ray angiography: it involves no sedation (unlike x-ray angiography), takes only 45 minutes (vs. half a day for x-ray angiography), and requires only the injection of a bolus of a safe "contrast" called gadolinium into the arm (vs. catheterization through an artery and injection of an iodinated chemical that can be toxic to the kidneys).
"There have been several publications demonstrating that MRA can help plan palliative surgery in patients with a mild form of peripheral vascular disease, or claudication," says Dr. Neil Khilnani, Associate Professor of Clinical Radiology at Weill Cornell, who, with Dr. Prince, is lead author of the study. "What is most striking and unique about the findings of this study is that MRA using the Weill Cornell technique is also excellent in patients with the more severe forms of PVD."
The study compares Weill Cornell's MRA with x-ray angiography performed on 35 limbs in the same group of 30 patients. The patients underwent both MRAs (which combined two-dimensional "digital subtraction angiograms" and three-dimensional "spoiled gradient-recalled-echo bolus chase" angiograms) and conventional x-ray angiograms. In undergoing MRA, the patients had a contrast material injected into a vein in their arm, and they then passed through the donut-shaped magnet of an MRI machine, which scanned the movement of the contrast material down through their arteries.
Fifteen of the patients, with 15 symptomatic limbs, were being evaluated for severe problems that might require amputation (such as gangrene, poorly healing diabetic ulcers, or ischemic rest pain). The 15 others, with 20 symptomatic limbs, suffered from milder symptoms of claudication. Nineteen of the patients were men, and 11 women, and the average age was 67.9 years.
Three cardiovascular and interventional radiologists evaluated the records engendered by the two techniques. These records are like photographic negatives, showing the treelike arterial systems from the torso down to the feet. In over 90% of the questions calling for judgment, the radiologists' evaluations of the nature and location of the blockages—and the recommendations for treatment—were the same whether they were based on the MRAs or on the traditional x-ray angiograms, and whether they involved patients with mild or severe symptoms. Even when the judgments were different, the treatment called for by the newer MRA technology was still appropriate when reviewed by the traditional angiogram.
The authors conclude that this "preliminary" study clearly demonstrates a way to "extend the utility of MR angiography to provide reliable treatment planning information for patients with claudication, as well as patients who are being evaluated for limb salvage."
Dr. Khilnani observes that no other Medical Center has developed the technique for MRA to the extent of Weill Cornell. Weill Cornell has applied for patents for several inventions in and enhancements of MRA technology.
Collaborating authors of Dr. Khilnani's article are Drs. Priscilla A. Winchester, David W. Trost, Harry L. Bush, Jr., Richard Watts, and Yi Wang, and Erez Vidan—all of Weill Cornell.
The same issue of Radiology contains another article, of which Dr. Prince is the lead author, which is of interest to specialists in discussing the physiology of the gadolinium contrast's flow down the atherosclerotic arteries of the legs and how this correlates with the patient's medical problems. In addition, Dr. Prince has a new book articulating the nuances of these MRA techniques, published by Springer-Verlag.