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J Thorac Cardiovasc Surg 1996;111:895-896
© 1996 Mosby, Inc.
BRIEF COMMUNICATIONS |
Nagoya, Japan
From the First Department of Surgery, Nagoya City University Medical School, Nagoya, Japan.
Received for publication August 22, 1995 Accepted for publication August 29, 1995.
Kawasaki disease, a generalized vasculitis of unknown etiology, is becoming one of the leading causes of acquired heart disease in children. In the acute phase of illness, cardiac findings may reveal the involvement of the pericardium, myocardium, endocardium, and coronary arteries. Complications involving the coronary arteries are the most common causes of both early and late morbidity and mortality.
1 Valvular heart disease, such as primary mitral regurgitation, rarely occurs as a complication and may result in severe congestive heart failure. We report a case of mitral regurgitation caused by ruptured chordae tendineae in a patient with Kawasaki disease who underwent successful valve repair. Rupture of the chordae tendineae has not been previously reported as a cause of mitral regurgitation in Kawasaki disease.
The patient's Kawasaki disease was diagnosed at 3 months of age, when he had 5 days of fever, truncal rash, erythema of the palms and lips, bilateral conjunctival injection, and cervical lymphadenopathy. His serum C–reactive protein concentration was 9.1 mg/dl. He was treated 6 days after the onset of illness with high-dose aspirin and intravenous gamma globulin at a dosage of 400 mg/kg per day for 3 days. The patient's clinical features improved rapidly, and his serum C–reactive protein concentration decreased to 0.7 mg/dl. His condition remained stable until day 24 of his illness, when a II/VI apical systolic murmur suddenly developed and his serum C–reactive protein concentration increased to 6.8 mg/dl. The patient had no fever at that time. Two-dimensional echocardiography and Doppler examination demonstrated mild mitral regurgitation without appreciable abnormalities of the coronary arteries. During a 3-day period, the patient came to have congestive heart failure as a result of mitral regurgitation. Intravenous gamma globulin was again administered to treat a recurrence of acute Kawasaki disease. Evaluation indicated rapid resolution of systemic inflammation, but severe heart failure resulting from significant mitral regurgitation persisted.
Three months after the onset of illness, the patient was referred to our hospital for further evaluation. Cardiac catheterization confirmed the presence of grade 4/4 mitral regurgitation with associated pulmonary hypertension and a markedly dilatated left ventricle without evidence of hypokinesia or akinesia. Coronary angiography revealed normal coronary arteries. The pulmonary artery pressure was 78/35 mm Hg and the pulmonary artery resistence index was calculated to be 7.8 U · m2.
At 12 months of age, the patient underwent successful mitral valve repair for symptoms of persistent heart failure and poor weight gain. The middle portion of the posterior leaflet of the mitral valve was slightly thickened and prolapsed. This prolapse was caused by rupture of the chordae tendineae attached to the free edge of the valve. The papillary muscles and the anterior leaflet of the mitral valve appeared normal. The posterior leaflet underwent quadrangular resection at the prolapsed site, and the gap created by the resected posterior leaflet was corrected by annular plication. A total circular annuloplasty was performed to repair the enlarged mitral orifice, resulting in an orifice diameter of 14 mm. Intraoperative Doppler echocardiography indicated trace mitral regurgitation. Histologic examination of the excised mitral valve leaflet revealed the abscence of valvulitis. The patient had an uneventful postoperstive recovery, and cardiac catheterization was performed 3 weeks after operation. Left ventriculography demonstrated the complete absence of mitral regurgitation. Pulmonary artery pressure and pulmonary artery resistance index were reduced to 40/15 mm Hg and 3.5 U · m2, respectively.
It is well known that mitral regurgitation occurs in the acute phase of Kawasaki disease as a result of acute valvulitis, papillary muscle dysfunction, or myocardial infarction. 2-5 Mild, inaudible mitral regurgitation is frequently detected by Doppler echocardiography during the acute phase of illness but rapidly improves. This valvular disease may be a result of papillary muscle dysfunction caused by a pancarditis. 2 Although the mechanism of myocarditis in Kawasaki disease is unknown, autoimmune mechanisms may be responsible for the changes seen in myocardial structures. Because of the functional reversibility of the myocarditis seen in Kawasaki disease, the target of autoimmune attack is suggested to be a relatively renewable structure, such as an intramyocardial microvessel. 1 In contrast, mitral regurgitation with an audible murmur has been described in about 1% of patients with Kawasaki disease. Chronic mitral regurgitation may be caused by involvement of the valve and its associated papillary muscles as a result of valvulitis or coronary artery stenosis. 3 Surgical repair for persistent mitral regurgitation resulting from Kawasaki disease has been described as difficult because of the high incidence of severe associated ischemic heart disease. When required, the valvular disease has occasionally been treated through surgical intervention such as mitral annuloplasty or valve replacement. 4,5
In our patient, a favorable clinical response to the initial therapy was achieved in the acute phase of Kawasaki disease and the coronary arteries were not affected. On day 24 of the illness, however, mitral regurgitation with an audible murmur occured suddenly, resulting in the rapid development of severe heart failure. Doppler echocardiography demonstrated prolapse of the posterior leaflet of the mitral valve, which before operation was attributed to rupture of the papillary muscle in the setting of recurrent myocarditis. Rupture of the chordae tendineae was confirmed at the time of operation; however, there was no evidence of valvulitis. The valve was successfully repaired by mitral valvuloplasty with total circular annuloplasty.
Results of this case suggest that initial mild mitral regurgitation may be attributable to papillary muscle dysfunction caused by recurrent myocarditis. Severe mitral regurgitation, however, may be caused by chordal rupture that occurs because of functional impairment of the valve apparatus. This is the first report of mitral regurgitation resulting from ruptured chordae tendineae in a patient with Kawasaki disease. Evaluation of similar patients will be necessary to investigate in greater detail mechanisms responsible for chordal rupture.
Footnotes
J THORAC CARDIOVASC SURG 1996;111:895-6 
References
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