Good long-term outlook for patients who survive Kawasaki disease

By Will Boggs MD

NEW YORK (Reuters Health) - Children who survive Kawasaki disease can look forward to few long-term cardiovascular complications, according to a retrospective study.

"I think the main value of this study is that it provides reassurance to pediatricians, parents, and children with Kawasaki disease that, with current therapies and a good initial outcome (no persistent aneurysm, which is the norm), 'interim' term complication rates appear to be very low," Dr. Jonathan G. Zaroff from Kaiser San Francisco Medical Center told Reuters Health. "There are occasional complications in patients who develop persistent aneurysms, but that is an increasingly rare scenario."

Coronary aneurysms often complicate Kawasaki disease, but early treatment with intravenous immunoglobulin (IVIg) and aspirin has decreased the rate of coronary aneurysm formation to between 3% and 5%. There are few reports on the long-term outcomes after Kawasaki disease in the modern treatment era.

Dr. Zaroff and colleagues used data from the Kaiser Permanente Northern California databases to evaluate the long-term rates of adverse cardiovascular events in 546 patients with confirmed Kawasaki disease and at least one year of follow-up, and in 2218 matched non-Kawasaki disease controls.

More than three-quarters of the patients received standard therapy with aspirin and IVIg, and 87% of patients received at least one of these medications. Only 25 patients (5%) developed coronary aneurysms that persisted on the last echocardiogram.

Overall, the rates of adverse events did not differ significantly between the Kawasaki disease and non-Kawasaki disease groups during an average follow-up period of 14.6 years.

There were only five adverse events (three of them before age 15) among the Kawasaki disease patients: one death from coronary artery disease, one sudden cardiac death without evidence of thrombosis or infarct on autopsy, one acute coronary syndrome (ACS) resulting from aneurysm thrombosis, and two other cases of ACS.

Four of the five adverse events (including both of the long-term complications) occurred in patients with persistent coronary aneurysm, the authors reported online January 20th in Pediatrics.

"Getting children with acute Kawasaki disease properly treated is vitally important in order to improve both short and intermediate-term outcomes," Dr. Zaroff said. "Once it becomes clear that there will be no persistent aneurysm, the risk of cardiovascular events over the next 10 to 15 years appears to be very low."

"The present study doesn't tell us about risk later in life, so we plan to look at the cohort again, every 10 years," Dr. Zaroff said. "Until we have that kind of longer-term data, it would be wise for physicians managing adult survivors of Kawasaki disease to be aware that these patients could have an increased risk of hypertension and vascular complications later in life."

Dr. Yosikazu Nakamura from Jichi Medical University, Shimotsuke, Tochigi, Japan recently reviewed mortality among Kawasaki disease patients in Japan. He told Reuters Health in an email, "Patients with cardiac sequelae must be managed by pediatric cardiologists. Patients without cardiac sequelae should remember the history of Kawasaki disease, because cardiovascular risk might elevate when (they're in their forties or fifties) because of the advanced atherosclerosis due to the vasculitis in infants and toddlers."

Dr. David Burgner from Murdoch Childrens Research Institute in Melbourne, Australia has also studied outcomes of Kawasaki disease. He told Reuters Health by email, "One key point is that follow-up was limited to about 15 years and the study population may have not been entirely representative of those at highest risk of cardiovascular disease anyway. So we still cannot be certain whether there are more subtle increases in cardiovascular risk following Kawasaki disease as patients age."

"On the other hand, the risk for most Kawasaki disease patients may not be significantly increased at all throughout their life," Dr. Burgner said. "We still need larger studies across different populations with longer follow-up to be able to answer these key questions."

"All Kawasaki disease patients should have careful attention paid to other proven cardiovascular risk factors, such as obesity, diabetes, smoking, hypertension and lack of physical activity," Dr. Burgner concluded. "We still don't know what the long term cardiovascular risks are following Kawasaki disease, so as these patients approach the age where these outcomes become common in the general population, reducing modifiable cardiovascular risk factors becomes increasingly important."

Dr. Jane C. Burns, who directs the Kawasaki Disease Research Center at Rady Children's Hospital San Diego and UCSD School of Medicine in La Jolla, California, told Reuters Health that she too wouldn't consider 15 years' follow-up to be long-term. "There is pathologic evidence, which wasn't discussed in the paper, that Kawasaki disease patients dying late after Kawasaki disease of other causes have easily demonstrable changes in the coronary and other medium -sized arteries," she said in an email.

"We really need a registry of Kawasaki disease and to follow deaths from non-Kawasaki disease causes so that we can really get a handle on these long-term pathologic changes," Dr. Burns said. "The existing data coupled with the studies of decreased fractional flow reserve and decreased arterial compliance and elastance all suggest that there may be problems for these patients in the third to fifth decade of life."

"This is the beginning of the story, not the end," Dr. Burns said.

SOURCE: http://bit.ly/1dBjr5j

Pediatrics 2014.

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