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Coronary artery compression due to implantation of a transcatheter pulmonary valve can be catastrophic and is often associated with abnormal anatomy, according to a study published online September 24, 2013, ahead of print in Circulation: Cardiovascular Interventions. To avoid this potential complication, the authors recommend that diagnostic angioplasty be performed in all such patients.
Thomas K. Jones, MD, of Seattle Children’s Hospital (Seattle, WA), and colleagues retrospectively analyzed 404 patients with a right ventricular outflow tract conduit or bioprosthetic pulmonary valve who underwent 407 catheterizations at 4 centers between January 2007 and February 2012. In total, 343 (85%) patients were implanted with the Melody pulmonary valve (Medtronic, Minneapolis, MN).
Compression Risk Tied to Anatomy
Twenty-one (4.7%) cases of coronary artery compression were observed with simultaneous right ventricular outflow tract angioplasty and coronary artery angiography. Abnormal anatomy was found in 68 (17%) patients overall and led to an increased risk of coronary artery compression compared with patients with normal anatomy (22% vs. 1.8%; P < 0.001). In particular, patients with abnormal anatomy and either tetralogy of Fallot or transposition of the great arteries were at increased risk compared to the remainder of the population (P < 0.001 for both).
Patients with compression were more likely to have abnormal anatomy than those without the complication (71% vs. 14%; P < 0.001). Also, the proportion of patients in the compression group with transposition of the great arteries was higher than that of patients in the noncompression group (33% vs. 8%; P < 0.001).
Test Angioplasty for All
“This relatively high frequency of a potentially life-threatening risk highlights the importance of evaluating the [coronary arteries] thoroughly in every prospective [transcatheter pulmonary valve] replacement procedure,” Dr. Jones and colleagues write. “Patients with abnormal [coronary artery] anatomy are more likely to be excluded because of risk of [coronary artery] compression. Patients with [tetralogy of Fallot] and an anomalous left [coronary artery] branch arising from the right [coronary artery] are at the highest risk of coronary compression, although this anatomic variation is not always associated with [compression] and should not be considered an absolute contraindication to [transcatheter pulmonary valve] replacement.”
Robert J. Sommer, MD, of Columbia University Medical Center (New York, NY), called the study “confirmatory.” He told TCTMD in a telephone interview that the large series of patients gives helpful information on how to conduct proper screening going forward.
“[The paper includes an image] of compression of a left coronary artery which looked like it was really far away from the conduit,” he observed. “It underscores the importance of actually testing with a balloon, doing angioplasty to stretch the conduit, . . . rather than just assuming that because the coronaries are far away there’s going to be no issue.”
Over time, “test balloon angioplasty of the [conduit] with simultaneous [coronary artery] angiography seems to be the most accurate way to simulate the changes that will occur with valve implantation,” the authors add.
Risk Inherent to Valve Implantation
Recognition of this complication is not new, Dr. Sommer noted. “People that do this procedure are very aware of it, but it’s important just to get the word out because as these devices become approved and more available, more people are going to be doing this. It’s part of the learning curve. People shouldn’t have to have complications when we know exactly what we’re dealing with already,” he said.
Furthermore, the authors emphasize the importance of preimplantation dynamic compression testing. But because this approach is not infallible, “proceed with caution if faced with a potentially high-risk situation,” they write, adding that future research may help identify other methods of predicting and evaluating compression in potential percutaneous valve recipients.
Lastly, the problem will not disappear with new, different devices, including the Sapien valve (Edwards Lifesciences, Irvine, CA), which Dr. Sommer reported is being tested in the pulmonary position. “It has nothing to do with the valve,” he explained. “It has to do with the transformation, the reshaping of the valve from a flat structure to a round structure and it taking up more space and compressing the heart posterior.”
The median age of patients was 18 years and the most common diagnosis was tetralogy of Fallot (56%).