MRI-VA improves view of anomalous coronary arteries

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Virtual angioscopy here to stay?

The MRI technique that Dr. Brothers and her colleagues reported on can provide important details of the anomalous coronary anatomy and about myocardial function, Philip S. Naimo, MD, Edward Buratto, MBBS, and Igor Konstantinov, MD, PhD, FRACS, of the Royal Children’s Hospital, University of Melbourne, wrote in their invited commentary. But, the ability to evaluate the neo-ostium after surgery had “particular value,” the commentators said (J. Thorac. Cardiovasc. Surg. 2016 Jul;152:211-12).

MRI with virtual angioscopy can fill help fill in the gaps where the significance of a narrowed neo-ostium is unknown, the commentators said. “The combination of anatomic information on the ostium size, shape, and location, as well as functional information on wall motion and myocardial perfusion, which can be provided by MRI-VA, would be particularly valuable in these patients,” they said.

They also pointed out that MRI-VA could be used in patients who have ongoing but otherwise undetected narrowing of the ostia after the unroofing procedure. At the same time, the technique will also require sufficient caseloads to maintain expertise. “It is safe to say that MRI-VA is here to stay,” Dr. Naimo, Dr. Buratto, and Dr. Konstantinov wrote. “The actual application of this virtual modality will need further refinement to be used routinely.”

The commentary authors had no financial relationships to disclose.



Failure to achieve a rounded and unobstructed ostia in children who have surgery to repair anomalous coronary arteries can put these children at continued risk for sudden death, but cardiac MRI with virtual angioscopy (VA) before and after the operation can give cardiologists a clear picture of a patient’s risk for sudden death and help direct ongoing management, according to a study in the July issue of the Journal of Thoracic and Cardiovascular Surgery (2016;152:205-10).

“Cardiac MRI with virtual angioscopy is an important tool for evaluating anomalous coronary anatomy, myocardial function, and ischemia and should be considered for initial and postoperative assessment of children with anomalous coronary arteries,” lead author Julie A. Brothers, MD, and her coauthors said in reporting their findings.

Anomalous coronary artery is a rare congenital condition in which the left coronary artery (LCA) originates from the right sinus or the right coronary artery (RCA) originates from the left coronary sinus. Dr. Brothers, a pediatric cardiologist, and her colleagues from the Children’s Hospital of Philadelphia and the University of Pennsylvania, also in Philadelphia, studied nine male patients who had operations for anomalous coronary arteries during Feb. 2009-May 2015 in what they said is the first study to document anomalous coronary artery anatomy both before and after surgery. The patients’ average age was 14.1 years; seven had right anomalous coronary arteries and two had left anomalous arteries. After the operations, MRI-VA revealed that two patients still had narrowing in the neo-orifices.

Previous reports recommend surgical repair for all patients with anomalous LCA and for symptomatic patients with anomalous RCA anatomy (Ann Thorac Surg. 2011;92:691-7; Ann Thorac Surg. 2014;98:941-5). MRI-VA allows the surgical team to survey the ostial stenosis before the operation “as if standing within the vessel itself,” Dr. Brothers and her coauthors wrote. Afterward, MRI-VA lets the surgeon and team see if the operation succeeded in repairing the orifices.

In the study population, VA before surgery confirmed elliptical, slit-like orifices in all patients. The operations involved unroofing procedures; two patients also had detachment and resuspension procedures during surgery. After surgery, VA showed that seven patients had round, patent, unobstructed repaired orifices; but two had orifices that were still narrow and somewhat stenotic, Dr. Brothers and her coauthors said. The study group had postoperative MRI-VA an average of 8.6 months after surgery.

“The significance of these findings is unknown; however, if the proposed mechanism of ischemia is due to a slit-like orifice, a continued stenotic orifice may place subjects at risk for sudden death,” the researchers said. The two study patients with the narrowed, stenotic orifices have remained symptom free, with no evidence of ischemia on exercise stress test or cardiac MRI. “These subjects will need to be followed up in the future to monitor for progression or resolution,” the study authors wrote.

Sudden cardiac death (SCD) is more common in anomalous aortic origin of the LCA than the RCA, Dr. Brothers and her colleagues said. Thus, an elliptical, slit-like neo-orifice is a concern because it can become blocked during exercise, possibly leading to lethal ventricular arrhythmia, they said. Ischemia in patients with anomalous coronary artery seems to result from a cumulative effect of exercise.

Patients who undergo the modified unroofing procedure typically have electrocardiography and echocardiography afterward and then get cleared to return to competitive sports in about 3 months if their stress test indicates it. Dr. Brothers and her colleagues said this activity recommendation may need alteration for those patients who have had a heart attack or sudden cardiac arrest, because they may remain at increased risk of SCD after surgery. “At the very least, additional imaging, such as with MRI-VA, should be used in this population,” the study authors said.

While Dr. Brothers and her colleagues acknowledged the small sample size is a limitation of the study, they also pointed out that anomalous coronary artery is a rare disease. They also noted that high-quality VA images can be difficult to obtain in noncompliant patients or those have arrhythmia or irregular breathing. “The images obtained in this study were acquired at an institution very familiar with pediatric cardiac coronary MRI and would be appropriate for assessing the coronary ostia with VA,” they said.

Dr. Brothers and her coauthors had no financial disclosures.

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