Adult life after KD

Children with KD may require life-long treatment, however, since the acute phase of KD is self-limited, KD diagnosis is often missed.

Consequently, individuals reach adulthood unaware of their KD history and face multiple cardiac complications. In the US and Japan alone, more than 14,000 new cases of KD are detected each year, yet no official guidelines exist to assist cardiologists in treating patients with a KD history.

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Once an individual’s normal arterial wall architecture has been damaged during the acute, inflammatory phase of KD, the affected segment will always have abnormal characteristics. Characteristics resulting from KD earlier in life can contribute to pathological cardiovascular conditions known as cardiovascular sequelae in adulthood. Growing numbers of young adults are presenting to cardiologists cardiovascular sequelae resulting from KD, including…

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• Cardiomyopathy (a disease of the heart muscle making it harder for the heart to pump blood around the body).

• Myocardial ischemia (insufficient blood supply to the heart tissue).

• Myocardial infarction (heart attack).

• Proliferation of myofibroblasts.

• Inability of the CA to dilate in times where myocardial oxygen demand is greater due to the arterial wall’s abnormal composition and calcification.

• Propensity to develop aneurisms in systemic arteries (arteries carrying blood from the heart to the body), and patients may present with symptoms of ischemia including weakness in a limb or extremity. These aneurisms have a high propensity to clot, sometimes completely, though many patients do well and can manage this symptom with low-dose aspirin and statins, avoiding bypass surgery.

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The management of cardiovascular sequelae conditions is different from atherosclerotic heart disease but there is little awareness in the adult cardiology community regarding the special challenges posed by cardiovascular sequelae of KD. For example, coronary artery aneurisms which can cause insufficient BP and myocardial ischemia in patients with KD history are associated with high risk of thrombosis (clotting) and stenosis (blocking or narrowing) at aneurism. These aneurisms are often highly calcified. In healthy individuals, narrowing of blood vessels can be treated with acetylcholine which induces vasodilation, however, in patients with cardiovascular sequelae from KD, the endothelium of the coronary artery demonstrates paradoxical vasoconstriction in response to this treatment, and thus treatment with acetylcholine is ineffective.

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It is therefore crucial for cardiologists to be able to make retrospective KD diagnosis with their adult patients. Cardiologists should, therefore, be familiar with KD signs and symptoms. It is also advised that doctors question the patient's parents about KD-compatible illness. Imaging studies such as magnetic resonance can also be useful. The detection of calcification of the arterial wall at places of former aneurysms is a sign of KD antecedent. However, since the KD etiology remains unknown, no specific test can be conducted for a retrospective KD diagnosis.

KD disease remains enigmatic. To improve the care of patients with antecedent KD, more systematic studies are necessary to collect data about patient histories and outcomes. This will allow the formulation of a hypothesis about the appropriate care and their test under clinical studies.

Research by Dr. J. Burns, UC San Diego School of Medicine 

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