Histopathological study on right endomyocardial biopsy of Kawasaki disease

Coronary microvascular dysfunction in childhood: An emerging pathological entity and its clinical implications

Coronary microvascular dysfunction (CMD) encompasses a spectrum of structural and functional alterations in coronary microvasculature resulting in impaired coronary blood flow and consequent myocardial ischemia without obstruction in epicardial coronary artery. The pathogenesis of CMD is complex involving both functional and structural alteration in the coronary microcirculation. In adults, CMD is predominantly discussed in context with anginal chest pain or existing ischemic heart disease and its risk factors. The presence of CMD suggests increased risk of adverse cardiovascular events independent of coronary atherosclerosis. Coronary microvascular dysfunction is also known in children but is rarely recognized due to paucity of concommitent coronary artery disease. Thus, its clinical presentation, underlying mechanism of impaired microcirculation, and prognostic significance are poorly understood. In this review article, we will overview variable CMD reported in children and delineate its emerging clinical significance.

Quantitative Assessment of Myocardial Edema by MR T2 Mapping in Children With Kawasaki Disease

BACKGROUND

Few studies assessed myocardial inflammation using Cardiovascular Magnetic Resonance Imaging in Kawasaki disease (KD) patients.

PURPOSE

To quantify myocardial edema in KD patients using T2 mapping and explore the independent predictors of T2 values.

STUDY TYPE

Prospective.

SUBJECTS

Ninety KD patients including 40 in acute phase (26 males, 65.0%) and 50 in chronic phase (34 males, 68.0%). Thirty-one healthy volunteers (21 males, 70.0%).

FIELD STRENGTH/SEQUENCE

3.0 T T2-weighted Turbo Spin Echo-Short Time of Inversion Recovery sequence, True fast imaging with steady precession flash sequence and fast low-angle shot 3D spoiled gradient echo sequence.

ASSESSMENT

T2 values were compared among KD groups and controls.

STATISTICAL TEST

Student's t test and Fisher's exact test; One-way analysis of variance; Pearson correlation analysis; Receiver operating curve analysis; Multivariable linear regression.

RESULTS

Global T2 value of KD patients in acute phase was the highest, followed by those of chronic-phase patients and controls (38.83 ± 2.41 msec vs. 37.55 ± 2.28 msec vs. 36.05 ± 1.64 msec). Regional T2 values showed a same trend. There were no significant differences in global and regional T2 values between KD patients with and without coronary artery (CA) dilation, no matter in acute or chronic phase (all KD patients: P = 0.51, 0.51, 0.53, 0.72; acute KD: P = 0.61, 0.37, 0.33, 0.83; chronic KD: P = 0.65, 0.79, 0.62, 0.79). No significant difference was observed in global T2 values between KD patients with Z score > 5.0 and 2.0 < Z score ≤ 5.0 (P = 0.65). Multivariate analysis demonstrated that stage of disease (β = -0.123) and heart rate (β = 0.280) were independently associated with global T2 values.

DATA CONCLUSION

The degree of myocardial edema was more severe in acute-phase than in chronic-phase KD patients. Myocardial edema persists in patients regardless of the existence or degree of CA dilation.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 2.

Cardiovascular Outcomes During Index Hospitalization in Children with Kawasaki Disease in Ontario, Canada

Kawasaki disease (KD) is a common childhood vasculitis associated with coronary artery aneurysms (CAA). However, there is limited published data on other cardiovascular events diagnosed during acute KD hospitalizations. Our objectives were to determine the incidence of cardiovascular events during acute KD hospitalizations, stratified by age at admission, CAA status, and pediatric intensive care unit (PICU) admission status. We identified all children (0-18 year) hospitalized with a new KD diagnosis in Ontario, between 1995 and 2018, through validated algorithms using population health administrative databases. We excluded children previously diagnosed with KD and non-Ontario residents. We evaluated for cardiovascular events that occurred during the acute KD hospitalizations, defined by administrative coding. Among 4597 children hospitalized with KD, 3307 (71.9%) were aged 0-4 years, median length of stay was 3 days (IQR 2-4), 113 children (2.5%) had PICU admissions, and 119 (2.6%) were diagnosed with CAA. During acute hospitalization, 75 children were diagnosed with myocarditis or pericarditis (1.6%), 47 with arrhythmias (1.0%), 25 with heart failure (0.5%), and ≤ 5 with acute MI (≤ 0.1%). Seven children underwent cardiovascular procedures (0.2%). Older children (10-18 years), children with CAA, and children admitted to the PICU were more likely to experience cardiovascular events, compared with children aged 0-4 years, without CAA or non-PICU admissions, respectively. The frequency of non-CAA cardiovascular events during acute KD hospitalizations did not change significantly between 1995 and 2018. During acute KD hospitalizations, older children, children with CAA, and PICU admissions are at higher risk of cardiovascular complications, justifying closer monitoring of these high-risk individuals.

Big Tests in Little People

Can laboratory tests that are routinely used in adult patients also be used in pediatric patients? Does the current literature support the routine use of troponin, brain natriuretic peptide, D-dimer, and lactate in children? Adult problems such as acute coronary syndrome and pulmonary embolism are rare in pediatrics, and there is a paucity of literature on how blood tests commonly used to help diagnose these conditions in adults play a role in the diagnosis and management of children. This article presents the literature about 4 common blood tests and examines the clinical applications of each.

Is there myocardial involvement in children with long-term follow-up for Kawasaki disease? A study based on two-dimensional speckle tracking echocardiography

Objective

This study aimed to determine the possibility of subclinical myocardial dysfunction detected by strain echocardiography in the late period of children with Kawasaki disease.

Material and Methods

The study enrolled 30 patients with Kawasaki disease with a follow-up period of at least 12 months and 30 healthy age- and gender-matched children. During the follow-up period, standard echocardiography, pulsed and tissue Doppler, and strain echocardiography were recorded for both groups.

Results

The mean age at the time of the diagnosis was 2.6±2.3 years (2 months-11 years). The mean follow-up period after the diagnosis was 3.55±2.20 years. Conventional echocardiography, M mode, pulsed and tissue Doppler values, and myocard performance index did not reveal significant differences. Left ventricle strain and strain rate parameters obtained by apical four-, three-, and two-chamber views did not show statistical differences between patients and controls. There was a positive correlation between the duration of follow-up and global four- and three-chamber longitudinal strain and global longitudinal strain values (r=0.465, p=0.010; r=0.414, p=0.023; r=0.492, p=0.006, respectively), whereas global radial strain showed negative correlation (r=-0.517, p=0.003).

Conclusion

The analysis of systolic strain and strain rate did not detect a subclinical myocardial dysfunction in the long-term follow-up of Kawasaki disease. However, strain values showed variability with the follow-up periods, which indicates that Kawasaki disease might cause left ventricular dysfunction in the later phases. Therefore, a follow-up of children with a diagnosis of Kawasaki disease is of capital importance.

Myocardial fibrosis in patients with a history of Kawasaki disease

Objectives

Cardiac magnetic resonance (CMR) measurements of myocardial extracellular volume fraction (ECV) and late gadolinium enhancement (LGE) in patients with a history of Kawasaki disease (KD) were analyzed to determine whether fibrosis was increased compared to controls.

Methods

In this single center retrospective study, patients with KD who had a CMR with ECV measurement and LGE assessment were included. The ECV was calculated in the mid-left ventricle by measuring T1 values for blood pool and myocardium before and after gadolinium administration with a Look-Locker technique. CMR findings were compared to 20 control subjects.

Results

KD patients (n = 13) had a median age at CMR of 14.9 years (range, 7.5-36.0). Control subjects (n = 20) had a median age at CMR of 16 years (range, 11.0-36.0). Twelve KD patients had coronary aneurysms. The KD patients had a significantly lower indexed LV mass (p = 0.03) and LV mass/volume ratio (p = 0.01). ECV was not significantly different in KD patients and controls (0.26 (range, 0.20-0.30) vs. 0.25 (range, 0.18-0.28), p = 0.28). One KD patient (8%) had an increased (>0.28) ECV. LGE indicating focal fibrosis was found in 5 of 13 (38%) of KD patients. Patients with LGE tended to have a higher maximum coronary dimension z-score (p = 0.09).

Conclusions

In this study of KD patients, most of whom had aneurysms, ECV did not differ significantly from that in normal controls. Focal fibrosis based on LGE was common. Future larger studies should compare ECV in KD patients with and without aneurysms to define the risk of myocardial fibrosis after KD.

Echocardiographic Parameters During and Beyond Onset of Kawasaki Disease Correlate with Onset Serum N-Terminal pro-Brain Natriuretic Peptide (NT-proBNP)

The N-terminal proBNP (NT-proBNP), produced by cardiomyocytes, has several reported utilities and associations in acute Kawasaki disease (KD). The objective of this study is to examine the relationship between serum values of NT-proBNP at time of KD diagnosis with cardiac systolic, diastolic function and electrocardiographic changes, at onset of the disease and during the first year of follow-up. KD was diagnosed in 127 children between March 2007 and July 2014, mean diagnostic age 3.5 ± 2.9 years. Coronary artery maximum z score was 2.6 ± 2.8 (range - 0.6 to + 18.9), with giant aneurysm in 5/122 (4.1%). Age-adjusted NT-proBNP was 2.6 ± 1.6 z score, 78/122 (63.9%) > 2.0. There was a crescendo correlation between onset NT-proBNP z score and C-Reactive protein (CRP) serum levels (slope + 0.49, p < 0.001). There was a crescendo correlation between NT-proBNP z score and indexed left ventricular (LV) mass (slope + 1.86, p = 0.02), LV diastolic function parameter E/e' ratio (slope + 0.31, p = 0.04) and a decrescendo correlation with age-adjusted LV shortening fraction (SF) (- 0.63, p = 0.02). Lower SF z score, higher left ventricular mass index and E/e' ratio were associated with higher NT-proBNP z score, but without correlation with CRP levels. Within 2-3 months from the onset of the disease, there was a resolution of the systolic dysfunction. Electrocardiographic parameter changes were associated with decreased LV shortening fraction but not with NT-proBNP. KD patients with elevated NT-proBNP at onset have sub-clinical myocardial involvement and might benefit from follow-up and continued evaluation, even in the absence of coronary artery involvement.

A Comprehensive Update on Kawasaki Disease Vasculitis and Myocarditis

PURPOSE OF THE REVIEW

Kawasaki disease (KD) is a childhood systemic vasculitis of unknown etiology that causes coronary artery aneurysms (CAA), and if left undiagnosed can result in long-term cardiovascular complications and adult cardiac disease. Up to 20% of KD children fail to respond to IVIG, the mainstay of therapy, highlighting the need for novel therapeutic strategies. Here we review the latest findings in the field regarding specific etiology, genetic associations, and advancements in treatment strategies to prevent coronary aneurysms.

RECENT FINDINGS

Recent discoveries using the Lactobacillus casei cell wall extract (LCWE)-induced KD vasculitis mouse model have accelerated the study of KD pathophysiology and have advanced treatment strategies including clinical trials for IL-1R antagonist, Anakinra. KD remains an elusive pediatric vasculitis syndrome and is the leading cause of acquired heart disease among children in the USA and developed countries. Advancements in combination treatment for refractory KD with further understanding of novel genetic risk factors serve as a solid foundation for future research endeavors in the field.

Myocardial fibrosis after adrenergic stimulation as a long-term sequela in a mouse model of Kawasaki disease vasculitis

Kawasaki disease (KD), the leading cause of acquired cardiac disease among children, is often associated with myocarditis that may lead to long-term myocardial dysfunction and fibrosis. Although those myocardial changes develop during the acute phase, they may persist for decades and closely correlate with long-term myocardial sequelae. Using the Lactobacillus casei cell wall extract-induced (LCWE-induced) KD vasculitis murine model, we investigated long-term cardiovascular sequelae, such as myocardial dysfunction, fibrosis, and coronary microvascular lesions following adrenergic stimuli after established KD vasculitis. We found that adrenergic stimulation with isoproterenol following LCWE-induced KD vasculitis in mice was associated with increased risk of cardiac hypertrophy and myocardial fibrosis, diminished ejection fraction, and increased serum levels of brain natriuretic peptide. Myocardial fibrosis resulting from pharmacologic-induced exercise after KD development was IL-1 signaling dependent and was associated with a significant reduction in myocardial capillary CD31 expression, indicative of a rarefied myocardial capillary bed. These observations suggest that adrenergic stimulation after KD vasculitis may lead to cardiac hypertrophy and bridging fibrosis in the myocardium in the LCWE-induced KD vasculitis mouse model and that this process involves IL-1 signaling and diminished microvascular circulation in the myocardium.

Examining the Utility of Coronary Artery Lack of Tapering and Perivascular Brightness in Incomplete Kawasaki Disease

BACKGROUND

In 2017, the AHA published revised guidelines for the diagnosis of Kawasaki disease (KD). In the absence of compelling data supporting or refuting the utility of lack of tapering (LT) and perivascular brightness (PB), expert panel consensus removed LT and PB from consideration. We hypothesize that LT and PB are unreliable, subjective findings, non-specific to KD, which can be seen in systemic febrile illnesses without KD and in normal controls.

METHODS

We performed a single-center retrospective study from 1/2008 to 12/2016. De-identified coronary artery (CA) echocardiographic clips from patients 0-10 years old were interpreted blindly by six pediatric cardiologists. Subjects were grouped as follows: (1) healthy: afebrile with benign murmur, (2) KD: IVIG treatment, 4-5 clinical criteria at presentation, (3) incomplete KD (iKD): IVIG, 1-3 clinical criteria, (4) Febrile: ≥3 days of fever, no IVIG, KD not suspected. The presence or absence of LT and PB was recorded. Inter-rater and intra-rater reliabilities were analyzed using intra-class correlation coefficient, Fleiss' Kappa and Cohen's Kappa coefficients.

RESULTS

We interpreted 117 echocardiograms from healthy (27), KD (30), iKD (32), and febrile (28) subjects. Analysis showed moderate agreement in CA z score measurements. LT and PB were observed by most readers in control groups. LT exhibited fair inter-reader agreement (reliability coefficient 0.36) and PB slight inter-reader agreement (reliability coefficient 0.13). Intra-rater reliability was inconsistent for both parameters.

CONCLUSIONS

LT and PB are subjective, poorly reproducible features that can be seen in febrile patients without KD and in healthy children.

Diagnosis, Treatment, and Long-Term Management of Kawasaki Disease: A Scientific Statement for Health Professionals From the American Heart Association

BACKGROUND

Kawasaki disease is an acute vasculitis of childhood that leads to coronary artery aneurysms in ≈25% of untreated cases. It has been reported worldwide and is the leading cause of acquired heart disease in children in developed countries.

METHODS AND RESULTS

To revise the previous American Heart Association guidelines, a multidisciplinary writing group of experts was convened to review and appraise available evidence and practice-based opinion, as well as to provide updated recommendations for diagnosis, treatment of the acute illness, and long-term management. Although the cause remains unknown, discussion sections highlight new insights into the epidemiology, genetics, pathogenesis, pathology, natural history, and long-term outcomes. Prompt diagnosis is essential, and an updated algorithm defines supplemental information to be used to assist the diagnosis when classic clinical criteria are incomplete. Although intravenous immune globulin is the mainstay of initial treatment, the role for additional primary therapy in selected patients is discussed. Approximately 10% to 20% of patients do not respond to initial intravenous immune globulin, and recommendations for additional therapies are provided. Careful initial management of evolving coronary artery abnormalities is essential, necessitating an increased frequency of assessments and escalation of thromboprophylaxis. Risk stratification for long-term management is based primarily on maximal coronary artery luminal dimensions, normalized as Z scores, and is calibrated to both past and current involvement. Patients with aneurysms require life-long and uninterrupted cardiology follow-up.

CONCLUSIONS

These recommendations provide updated and best evidence-based guidance to healthcare providers who diagnose and manage Kawasaki disease, but clinical decision making should be individualized to specific patient circumstances.

Myocardial Strain and Strain Rate in Kawasaki Disease: Range, Recovery, and Relationship to Systemic Inflammation/Coronary Artery Dilation

BACKGROUND

Kawasaki Disease (KD), a systemic vasculitis of medium sized vessels, is the most common cause of acquired heart disease among children in the developed world. Some KD patients demonstrate echocardiographic evidence of depressed myocardial mechanics. However, the incidence, etiology, and reversibility of abnormal mechanics in KD patients remain undefined.

METHODS AND RESULTS

We retrospectively studied 41 KD patients and measured myocardial strain and strain rate by velocity vector imaging from pre-treatment and convalescent echocardiograms. Pre-treatment procalcitonin, C-reactive protein (CRP), and coronary artery z-scores were obtained in all patients and compared between the groups with preserved versus depressed acute phase mechanics. The change in mechanics between the acute and convalescent phases was also assessed. Patients with initially low longitudinal strain improved by the convalescent period (mean difference - 4.0%; p<0.005) with the greatest improvement occurring in patients with the lowest initial strain (-7.3%; p<0.05). Patients with higher initial strain did not change significantly by the convalescent period. Patients with lower longitudinal and circumferential strain demonstrated higher median procalcitonin levels (1.2 vs. 0.3 ng/mL; p<0.05 and 1.8 vs. 0.4 ng/mL; p<0.05 respectively) and a trend towards higher CRP, but no difference in coronary artery z-scores. Strain rate was not associated with inflammatory markers or coronary artery z-scores.

CONCLUSIONS

The range of strain found in our cohort was large. Improvement in mean strain was driven primarily by patients with lower initial strain. Lower strain was associated with increased markers of systemic inflammation, but not proximal coronary artery changes.

Outcomes of Kawasaki Disease: A Single-Center Experience

OBJECTIVES

Kawasaki disease (KD) is an acute systemic vasculitis of unknown etiology. Coronary artery lesions (CAL) develop in 15% to 20% of untreated cases. Our objective was to evaluate demographic, clinical, and laboratory features and short-intermediate coronary artery outcomes of children with KD.

PATIENTS AND METHODS

Medical records of patients with KD were retrospectively identified. Clinical information and echocardiography, laboratory, and angiographic results were noted using a standardized form.

RESULTS

The study included 44 patients with a mean age of the 29.72 ± 21 months (ranging from 1 month to 9.5 years). There were 28 male and 16 female patients; 20 patients were diagnosed as having had incomplete KD. Four cases with atypical presentation were significantly older than children with complete and incomplete KD; 17 patients (38.6 %) had coronary artery aneurysm (CAA), which declined to 6.8% after intravenous immunoglobulin (IVIG) treatment. Time between fever and diagnosis and abnormal levels of hemoglobin and platelets were all associated with CAA. The children were followed up for a mean of 36.39 ± 19 months (with a maximum of 16 years). Angiographic evolution and regression of CALs have been observed in 14 (82.3%) patients. Three patients in whom CALs persisted did not receive IVIG therapy because of delayed diagnosis.

CONCLUSIONS

Awareness of KD in children has led to an increase in the number of cases. Utility of IVIG treatment to reduce the coronary artery involvement in patients with delayed diagnoses should be discussed and considered. Long-term results are required to assess whether the KD represents a risk factor for coronary artery diseases seen during adulthood.

Cardiovascular biomarkers in acute Kawasaki disease

BACKGROUND

Endomycocardial biopsies have demonstrated that subclinical myocarditis is a universal feature of acute Kawasaki disease (KD).

METHODS

We investigated biochemical evidence of myocardial strain, oxidative stress, and cardiomyocyte injury in 55 acute KD subjects (30 with paired convalescent samples), 54 febrile control (FC), and 50 healthy control (HC) children by measuring concentrations of cardiovascular biomarkers.

RESULTS

Levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and soluble ST2 (sST2) were elevated in acute vs. convalescent KD, FC, and HC (p≤0.002), while γ-glutamyl transferase and alanine amino transferase as measures of oxidative stress were increased in acute vs. FC (p≤0.0002). Cardiac troponin I (cTnI) levels, using a highly sensitive assay, were elevated in 30% and 40% of paired acute and convalescent KD subjects, respectively, and normalized within two years of disease onset. NT-proBNP and sST2 negatively correlated with deceleration time, but only NT-proBNP correlated with MV E:A ratio and internal diameter of the coronary arteries (RCA/LAD Zworst).

CONCLUSIONS

NT-proBNP and sST2 were elevated in acute KD subjects and correlated with impaired myocardial relaxation. These findings, combined with elevated levels of cTnI, suggest that both cardiomyocyte stress and cell death are associated with myocardial inflammation in acute KD.

Biopsy-proven myocardial sequels in Kawasaki disease with giant coronary aneurysms

BACKGROUND

Although most Kawasaki disease with giant coronary aneurysms is asymptomatic, conventional investigations might not identify previous lesions, or all Kawasaki disease with giant aneurysms at risk of future myocardial lesions. We evaluated the long-term histopathology of the myocardium, especially of intramural small vessels in asymptomatic Kawasaki disease with giant aneurysms.

METHOD

The initial study comprised 16 consecutive Kawasaki patients - male-to-female ratio was 12:4 - aged from 2 to 12 years, and in the subsequent study, the same patients were aged from 4.9 to 16 years. Endomyocardial biopsies were histopathologically evaluated. Microangiopathies, mitochondrial abnormalities, and loss or disarray of myofibrils were compared by electron microscopy.

RESULTS

The incidence of histopathological abnormalities such as degeneration, hypertrophy, and inflammatory cell infiltration was quite high in the initial study, and inflammatory cell infiltration, interstitial fibrosis, and disarray were very noticeable at follow-up biopsies. The area of fibrous tissue was significantly higher in patients administered with intravenous immunoglobulin at follow-up biopsies. Electron microscopy showed microangiopathies including microthrombi within intramural small vessels in some patients at follow-up biopsies. The sites of the coronary aneurysms did not seem to have an impact on the biopsy findings, suggesting that the underlying pathophysiology is related to the original disease process.

CONCLUSIONS

Whether the abnormalities were due to direct myocardial injury, chronic ischaemia, repeated small-vessel thrombosis, or other problems associated only with biopsies, is difficult to determine. However, this subgroup had residual abnormal lesions in the myocardium. Follow-up should be more aggressive in this group of patients to identify myocardial damage that could be asymptomatic.

When children with Kawasaki disease grow up: Myocardial and vascular complications in adulthood

Kawasaki disease (KD) is an acute, self-limited vasculitis that typically occurs in young children and was first described by Japanese pediatrician Tomisaku Kawasaki in 1967. Although originally thought to be a rare condition, KD has become the most common cause of acquired heart disease in the pediatric age group in developed countries. The majority of patients with KD appear to have a benign prognosis, but a subset of patients with coronary artery aneurysms are at risk for ischemic events and require lifelong treatment. In the 4 decades that have passed since the initial recognition of KD, the number of patients reaching adulthood has continued to grow. Adult cardiologists will be increasingly involved in the management of these patients. Currently, there are no established guidelines for the evaluation and treatment of adult patients who have had KD. We review here the current literature that may be helpful to clinicians who care for adults who experienced KD in childhood.

Kawasaki Disease update

Kawasaki Disease is rapidly becoming the most common cause of acquired heart disease in children in both the developed and developing world. Its etiology remains a mystery but important progress has been made in characterizing the features of the arterial wall and myocardial pathology and long-term clinical consequences. New treatments aimed at modifying the host immune response are currently under study. The genetic influence on susceptibility and disease outcome is an area of active research.

Searching for the cause of Kawasaki disease--cytoplasmic inclusion bodies provide new insight

Although Kawasaki disease (KD) is the most common cause of acquired heart disease in children in the developed world, its aetiology remains unknown. In this Opinion, Anne Rowley and colleagues discuss evidence, including recently identified cytoplasmic inclusion bodies, which suggests that KD is caused by an infectious agent.

Kawasaki disease (KD) has emerged as the most common cause of acquired heart disease in children in the developed world. The cause of KD remains unknown, although an as-yet unidentified infectious agent might be responsible. By determining the causative agent, we can improve diagnosis, therapy and prevention of KD. Recently, identification of an antigen-driven IgA response that was directed at cytoplasmic inclusion bodies in KD tissues has provided new insights that could unlock the mysteries of KD.

Diagnosis, treatment, and long-term management of Kawasaki disease: a statement for health professionals from the Committee on Rheumatic Fever, Endocarditis and Kawasaki Disease, Council on Cardiovascular Disease in the Young, American Heart Association

BACKGROUND

Kawasaki disease is an acute self-limited vasculitis of childhood that is characterized by fever, bilateral nonexudative conjunctivitis, erythema of the lips and oral mucosa, changes in the extremities, rash, and cervical lymphadenopathy. Coronary artery aneurysms or ectasia develop in approximately 15% to 25% of untreated children and may lead to ischemic heart disease or sudden death.

METHODS AND RESULTS

A multidisciplinary committee of experts was convened to revise the American Heart Association recommendations for diagnosis, treatment, and long-term management of Kawasaki disease. The writing group proposes a new algorithm to aid clinicians in deciding which children with fever for > or =5 days and < or =4 classic criteria should undergo echocardiography, receive intravenous gamma globulin (IVIG) treatment, or both for Kawasaki disease. The writing group reviews the available data regarding the initial treatment for children with acute Kawasaki disease, as well for those who have persistent or recrudescent fever despite initial therapy with IVIG, including IVIG retreatment and treatment with corticosteroids, tumor necrosis factor-alpha antagonists, and abciximab. Long-term management of patients with Kawasaki disease is tailored to the degree of coronary involvement; recommendations regarding antiplatelet and anticoagulant therapy, physical activity, follow-up assessment, and the appropriate diagnostic procedures to evaluate cardiac disease are classified according to risk strata.

CONCLUSIONS

Recommendations for the initial evaluation, treatment in the acute phase, and long-term management of patients with Kawasaki disease are intended to assist physicians in understanding the range of acceptable approaches for caring for patients with Kawasaki disease. The ultimate decisions for case management must be made by physicians in light of the particular conditions presented by individual patients.

Adrenomedullin is highly expressed in blood monocytes associated with acute Kawasaki disease: a microarray gene expression study

Kawasaki disease (KD) is an acute inflammatory disorder of children frequently associated with the development of coronary artery abnormalities. Although a great deal is known about inflammatory and immune responses in acute KD, the mechanisms linking the immune response to vascular changes are not known. To gain further insight into this process, we performed a microarray gene expression analysis on RNA isolated from the peripheral blood mononuclear cells of four patients with KD during both their acute and convalescent phases. Forty-seven genes of 7129 genes examined showed an increased expression in three or all four patients in the acute compared with the convalescent phase of KD. Fourteen of these genes were significantly (p < 0.05) up-regulated, including several inflammatory response genes (e.g. S-100 A9 protein) and also anti-inflammatory genes (e.g. TSG-6). Of greatest interest, the adrenomedullin (ADM) gene, known to be associated with coronary artery vasodilation, was up-regulated in the acute phase of KD (p = 0.024). Up-regulation of ADM in the acute phase of KD was confirmed in peripheral blood mononuclear cells of 11 additional KD patients by reverse transcriptase-PCR (p < 0.01). Isolated blood monocytes but not lymphocytes were demonstrated by real-time PCR to have increased ADM mRNA (p = 0.01). Plasma ADM protein level in 32 additional KD patients was also confirmed to be higher in acute KD compared with convalescent KD (p < 0.032). It is interesting that from microarray results, other molecules known to be associated with coronary dilation, including nitric oxide, prostacyclin, acetylcholine, bradykinin, substance P, and serotonin, were not elevated in acute KD. Our current study suggests that ADM-expressing monocytes that infiltrate the coronary vascular wall may be the cause of coronary dilation in the acute phase of KD.

Diagnosis, treatment, and long-term management of Kawasaki disease: a statement for health professionals from the Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease, Council on Cardiovascular Disease in the Young, American Heart Association

BACKGROUND

Kawasaki disease is an acute self-limited vasculitis of childhood that is characterized by fever, bilateral nonexudative conjunctivitis, erythema of the lips and oral mucosa, changes in the extremities, rash, and cervical lymphadenopathy. Coronary artery aneurysms or ectasia develop in approximately 15% to 25% of untreated children and may lead to ischemic heart disease or sudden death.

METHODS AND RESULTS

A multidisciplinary committee of experts was convened to revise the American Heart Association recommendations for diagnosis, treatment, and long-term management of Kawasaki disease. The writing group proposes a new algorithm to aid clinicians in deciding which children with fever for > or =5 days and < or =4 classic criteria should undergo echocardiography [correction], receive intravenous gamma globulin (IVIG) treatment, or both for Kawasaki disease. The writing group reviews the available data regarding the initial treatment for children with acute Kawasaki disease, as well for those who have persistent or recrudescent fever despite initial therapy with IVIG, including IVIG retreatment and treatment with corticosteroids, tumor necrosis factor-alpha antagonists, and abciximab. Long-term management of patients with Kawasaki disease is tailored to the degree of coronary involvement; recommendations regarding antiplatelet and anticoagulant therapy, physical activity, follow-up assessment, and the appropriate diagnostic procedures to evaluate cardiac disease are classified according to risk strata.

CONCLUSIONS

Recommendations for the initial evaluation, treatment in the acute phase, and long-term management of patients with Kawasaki disease are intended to assist physicians in understanding the range of acceptable approaches for caring for patients with Kawasaki disease. The ultimate decisions for case management must be made by physicians in light of the particular conditions presented by individual patients.

Kawasaki disease

Kawasaki disease is a leading cause of acquired heart disease in children in the USA. An acute vasculitis of unknown etiology, it occurs predominantly in infancy and early childhood, and more rarely in teenagers. Coronary artery aneurysms or ectasia develop in approximately 15-25% of children with the disease. Treatment with intravenous gamma globulin, 2 g per kg, in the acute phase reduces this risk three- to fivefold. Angiographic resolution occurs in approximately one-half of aneurysmal arterial segments, but these show persistent histologic and functional abnormalities. The remainder continue to be aneurysmal, often with development of progressive stenosis or occlusion. The worst prognosis occurs in children with so-called 'giant aneurysms', i.e. those with a maximum diameter greater than 8 mm, because thrombosis is promoted both by sluggish blood flow within the massively dilated vascular space and by the frequent development of stenotic lesions. Serial stress tests with myocardial imaging are mandatory in the management of patients with Kawasaki disease and significant coronary artery disease to determine the need for coronary angiography and transcatheter interventions or coronary bypass surgery. Continued long-term surveillance in patients with and without detected coronary abnormalities is necessary to determine the natural history of Kawasaki disease.

Anti-Human Cardiac Myosin Autoantibodies in Kawasaki Syndrome

Kawasaki syndrome (KS) is the major cause of acquired heart disease in children. Although acute myocarditis is observed in most patients with KS, its pathogenesis is unknown. Because antimyosin autoantibodies are present in autoimmune myocarditis and rheumatic carditis, the purpose of the current study was to determine whether anticardiac myosin Abs might be present during the acute stage of KS. Sera from KS patients as well as age-matched febrile controls and normal adults were compared for reactivity with human cardiac myosin in ELISAs and Western blot assays. A total of 5 of 13 KS sera, as compared with 5 of 8 acute rheumatic fever sera, contained Ab titers to human cardiac myosin that were significantly higher than those found in control sera. Both cardiac and skeletal myosins were recognized in the ELISA by KS sera, although stronger reactivity was observed to human cardiac myosin. Only IgM antimyosin Abs from KS sera were significantly elevated relative to control sera. KS sera containing antimyosin Abs recognized synthetic peptides from the light meromyosin region of the human cardiac myosin molecule and had a different pattern of reactivity than acute rheumatic fever sera, further supporting the association of antimyosin Ab with KS. These Abs may contribute to the pathogenesis of acute myocarditis found in patients with KS.

Ultrastructural characteristics of myocardial and coronary microvascular lesions in Kawasaki disease

Kawasaki disease (KD) is an acute febrile mucocutaneous lymph node syndrome with multisystemic vasculitis affecting mainly infants and children. Although several studies on cardiovascular lesions in KD have been done at the light microscopic level, the ultrastructural characteristics and incidences of these lesions have not been well defined. In order to investigate the myocardial and coronary microvascular sequelae in KD, we performed an ultrastructural study on endomyocardial biopsy specimens obtained during follow-up from 54 patients who had typical clinical manifestations of KD, of whom 47 had associated coronary aneurysms as demonstrated by coronary arteriography (CAG) or two-dimensional echocardiography in the acute or healed stage. The average age of onset was 2.2 years old and the duration of illness was from 2 months to 23 years. Follow-up CAG showed that the coronary aneurysms persisted in 33 of the 47 patients (8 with associated stenosis) and resolved in the remaining 14 patients. Ultrastructurally, the myocardial changes revealed hypertrophy, various degrees of degeneration, proliferation and abnormality of mitochondria, infiltration of a small number of lymphocytes, and fibrosis. The coronary microvascular lesion was characterized by microvascular dilatation, endothelial cell injury, platelet aggregation with thrombosis, and stenotic lumen with thickened walls in the small arterioles. It persisted after convalescent stage even up to 23 years and closely correlated with the myocardial sequelae. Moreover, significantly increased incidences of myocardial and coronary microvascular lesions were found in patients with coronary artery lesion. These findings suggest the coronary microvascular lesion as a possible underlying factor of persistent sequelae in KD.

The potential role of bacterial superantigens in the pathogenesis of Kawasaki syndrome

Kawasaki syndrome is an acute multisystem vasculitis of infancy and early childhood associated with high fever, mucocutaneous inflammation, and the development of coronary artery abnormalities. Despite the widely held belief that Kawasaki syndrome is an infectious disease, investigations have failed to identify a causal organism. Previous studies have demonstrated that this illness is associated with marked activation of monocyte/macrophages and the selective expansion of V beta 2-, less so, of V beta 8.1/8.2-expressing T cells in the peripheral blood from Kawasaki syndrome patients during the acute phase of their illness. These immunologic features are characteristic of diseases that are caused by bacterial toxins which act as superantigens. Staphylococcal enterotoxins and streptococcal exotoxins are prototypic superantigens which stimulate large populations of T cells expressing particular T-cell receptor beta-chain variable (V beta) gene segments. Using the V beta 2+ T-cell expansion as an "immunologic footprint" for a superantigen, we have extended these observations to the identification and isolation of a novel clone of toxic shock syndrome toxin-1-producing Staphylococcus aureus in the majority of patients with Kawasaki syndrome and streptococcal pyrogenic exotoxin B/streptococcal pyrogenic exotoxin C-producing streptococci in a minority of Kawasaki syndrome patients. Toxic shock syndrome toxin-1, streptococcal pyrogenic exotoxin B, and streptococcal pyrogenic exotoxin C are known to stimulate V beta 2+ T cells. These observations support the hypothesis that the activation of V beta 2+ T cells during the acute phase of Kawasaki syndrome is caused by bacterial superantigen(s).

Acute heart failure and acute renal failure in Kawasaki disease

Acute renal failure and acute heart failure are rare in Kawasaki disease. We experienced two patients with Kawasaki disease who presented acute renal failure and acute heart failure. These two patients gave us an important insight into the understanding of water balance and fluid therapy in Kawasaki disease. One patients showed acute prerenal failure due to fluid exudation from the intravascular to the extravascular space, and subsequent acute heart failure. The other patient showed acute heart failure caused by fluid infusion for the treatment of dehydration. It is suggested that acute renal failure could be caused by a fluid shift from the intravascular to the extravascular space in Kawasaki disease. It is also demonstrated that the reserve of cardiac function could be decreased in patients with Kawasaki disease due to myocarditis even with normal echocardiography and chest X-rays.

Estimation of myocardial damage in Kawasaki disease using antimyosin antibody

In a retrospective study, 121 children with Kawasaki disease (KD) were investigated to determine (i) the incidence of myocardial damage using the antimyosin antibody (AMA) titer; (ii) the differences in the electrocardiograms between the AMA-positive and -negative patients; and (iii) the effect of treatment with intravenous gamma globulin (IVGG) on the AMA. Comparisons were made with 117 normal children (controls). Patients with KD showed a significantly higher mean AMA titer and more patients were positive for AMA than the controls. The AMA titer in the KD group was not related to the presence of coronary artery lesions. Electrocardiograms obtained during the acute and the convalescent stage of KD revealed that patients positive for AMA had a significantly lower voltage of T wave in lead V6 at week four than at week two of illness, whereas patients negative for AMA showed no T wave change after week two. The group treated with IVGG showed a significantly lower AMA titer than that not given IVGG. These observations suggest that myocardial damage occurs in some patients with KD which is unrelated to the presence of coronary artery lesions and that the treatment with IVGG reduces the AMA titer in patients with KD.

Histopathologic and coronary angiographic assessment of effectiveness of aspirin or aspirin-and-gammaglobulin in Kawasaki disease

Coronary angiography and right ventricular endomyocardial biopsy were performed in 36 children during convalescence (days of illness 23-86; mean = 41.5 days) following acute Kawasaki disease. Treatment of the acute stage was not randomized; it consisted of aspirin alone in 14 subjects (during the years 1980-88), and gammaglobulin and aspirin in 22 subjects (1984-91). The dosage of aspirin was 30 mg/kg orally during the acute febrile stage and 5-10 mg/kg orally after lysis of fever. The dosage of gammaglobulin was 200 mg/kg x 5 days in 19 patients, 200 mg/kg x 3 days in one patient, 200 mg/kg x 1 day + 400 mg/kg x 4 days in one patient and 200 mg/kg x 4 days + 400 mg/kg x 4 days in one patient. Among the 14 patients treated with aspirin alone, large coronary aneurysms were noted in four, moderate aneurysms in three and transient aneurysms in one. Among 22 patients treated with gammaglobulin, only five had aneurysms and these were transient. The histopathological (HP) score based on myocardial disarrangement, degeneration and hypertrophy; interstitial edema, large mononuclear cell infiltration and fibrosis; and endocardial abnormalities was higher in the aspirin group than in gammaglobulin group. Moderate to severe HP changes were noted in five subjects in the aspirin group, while moderate HP changes were found in only two subjects in the gammaglobulin group. Gammaglobulin therapy not only reduced the incidence of the coronary arterial lesions but also reduced the severity of myocardial damage from moderate or severe to mild in Kawasaki disease.

Safety and utility of endomyocardial biopsy in infants, children and adolescents: a review of 66 procedures in 53 patients

The benefits and risks of endomyocardial biopsy in infants, children and adolescents were determined by reviewing the indications for and complications and results of 66 procedures in 53 patients aged 2 months to 20 years. One patient had a pneumothorax, and three had a right ventricular perforation. Ventricular tachycardia developed in four patients; it was treated with lidocaine in three and was self-limited in one. The procedure was unsuccessful in two patients. Among 25 patients with a prebiopsy diagnosis of idiopathic dilated cardiomyopathy, microscopic features were consistent with cardiomyopathy in 24 (96%) and were normal in 1. Of nine patients with clinically suspected myocarditis, only two (22%) had microscopic evidence of inflammation, and seven had chronic nonspecific features suggestive of dilated cardiomyopathy. Of eight patients with unexplained arrhythmias, six (75%) had microscopic findings compatible with dilated cardiomyopathy and two had myocarditis. Biopsy tissue samples from seven patients with nondilated forms of cardiomyopathy (four hypertrophic, three restrictive) were consistent with the clinical diagnosis in six and were inadequate in one. Cardiac biopsies were also performed in four patients with other disorders. Among the 51 patients with adequate biopsy specimens, microscopic features were considered diagnostic in 5, confirmatory in 44 and not helpful in 2 with normal tissue. The results indicate that endomyocardial biopsy is safe in infants, children and adolescents. It is useful for the evaluation of cardiomyopathy and specific secondary forms of myocardial disease. There seems to be little correlation, however, between clinical and tissue diagnoses of myocarditis.

Endomyocardial biopsy in children with Kawasaki disease

To study the histopathology of the myocardium in Kawasaki Disease (KD) with various coronary angiographic findings, right endomyocardial biopsy specimens were evaluated on 20 boys and 16 girls with this disorder. KD with coronary artery lesions (CAL) showed various histopathological abnormalities, such as myocellular hypertrophy in 44%, degeneration in 61%, interstitial fibrosis in 44% and endomyocardial changes in 22%. KD without CAL revealed myocellular hypertrophy in 44%, degeneration in 50%, disarray in 28% and interstitial fibrosis in 6%. As in patients with long-standing KD, more than three years after onset, myocardial changes such as myocellular hypertrophy, disarray and interstitial fibrosis persisted, it is suggested that cardiomyopathy may develop in some patients with KD.

Correlation of electrocardiographic and echocardiographic changes in Kawasaki syndrome

To determine whether changes in ECGs correlated with abnormalities in echocardiograms in children with acute and convalescent Kawasaki syndrome, we undertook a retrospective analysis of 44 patients examined during the first 2 weeks of illness and followed for at least 6 months, 31 for longer than 1 year. We analyzed 360 ECGs, 282 echocardiograms, and clinical status. Results of echocardiography showed 18 children with myocardial dysfunction, pericardial effusion, and/or coronary arterial abnormalities (41%); 26 children had no abnormalities. All 18 of the former and all but 10 of the latter had abnormalities on serial ECGs that normalized on recovery. Thirty-four of 44 patients (77%) had ECG abnormalities. These abnormalities were most prevalent in the first month: 68% appeared in the first week, about 50% in the second to fourth weeks, 16% at 2 months, and 10% at 3 months. The type of ECG change did not predict the type of echocardiographic abnormality, except that low voltage of QRS was found only with pericardial effusion. The most frequent early changes were in T waves, which were flattened in 28 (64%). Later 12 patients had high, peaked, abnormal T waves. Prolonged PR interval occurred in 13 patients, seven of whom had echocardiographic abnormalities. Of six with prolonged QT interval, four had abnormal echocardiograms. The possibility of having an abnormal echocardiogram increased with the number of ECG changes: from 0 risk with no change to 37% for one, 47% for two, 80% for three, and 100% for four changes in serial ECGs. Both ECGs and echocardiograms are important in early and subsequent evaluation of these patients. Inasmuch as the ECGs showed abnormalities in 77% whereas echocardiograms showed changes in 41%, we believe that serial ECGs in comparison with prior tracings offer the more sensitive noninvasive indicator of pancarditis in young children during acute and convalescent Kawasaki syndrome.

Enzyme pattern and lipid peroxides in endomyocardial biopsies from patients with cardiomyopathy and myocarditis

Methods have been developed for measuring several biochemical parameters (isoenzymes of LDH and ASAT, glycogen phosphorylase, lipid peroxides) in extremely small tissue samples (0.2-1.8 mg) taken using a left ventricular biopsy technique. Endomyocardial biopsies from patients with dilative and hypertrophic cardiomyopathy (CMP) and with myocarditis were investigated and compared with a reference group without actual functional and morphological evidence of chronic heart disease. Patients with myocarditis showed the highest activities of LDH and its isoenzymes, ASAT, ASATm and glycogen phosphorylase and the highest concentration of lipid peroxides. In patients with hypertrophic CMP increased activities of glycogen phosphorylase and decreased activities of ASAT and ASATm have been found. In patients with dilative CMP slightly elevated ASAT and ASATm activities have been observed. The results obtained in this study suggest that the parameters investigated could be useful in differentiating between cardiomyopathies and myocarditis.

Left ventricular systolic function in children with coronary arterial lesion following Kawasaki disease

Seventy-five children with Kawasaki disease underwent quantitative left ventricular cineangiography, and angiographic measurements were made to obtain left ventricular ejection fraction (LVEF) and mean velocity of circumferential fiber shortening (mVcf). In addition, left ventricular pressure and echocardiograms were taken simultaneously before and after nitroprusside infusion using a micromanometer. In the present study, the slope of the line describing end-systolic pressure-diameter relations (Emax) was calculated. The 75 children with Kawasaki disease were classified into five groups according to the severity or condition of associated coronary lesions: Grade 0 group (normal--no significant enlargement of the coronary artery is seen), grade 1 group (mild state of lesion--the maximum diameter of the coronary artery is 4.0 mm or less), grade 2 group (moderate state of lesion--the maximum diameter of the coronary artery is 4.0-8.0 mm), grade 3 group (serious state of lesion--the maximum diameter of the coronary artery is 8.0 mm or over, i.e., giant aneurysm), and stenotic lesion (SL) group (myocardial infarction or various other stenotic lesions are involved). Each group was investigated for each index of left ventricular function. In the grade 2 group, the averaged value of LVEF was slightly smaller than those for the grade 0 and 1 groups, while in the grade 3 and SL groups, the averaged values of LVEF were markedly smaller than those for all other groups. Grade 3 and SL groups showed averaged mVcf values that were smaller than those for other groups, while grade 2-3 and SL groups showed averaged values of Emax that were markedly smaller than those for the remaining groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Indication of aortocoronary by-pass for coronary arterial obstruction due to Kawasaki disease

Six patients with coronary arterial lesions due to Kawasaki disease underwent aortocoronary by-pass grafting at our institute. Before surgery, all of them had been closely monitored for some years by means of selective coronary arteriography, thallium myocardial imaging, electrocardiography (treadmill and/or Holter), and two-dimensional echo cardiography. Based on this experience, we propose the following guidelines as an indication for aortocoronary by-pass in such patients. First, the following three conditions should be satisfied: 1) The progress of coronary arterial lesions has been documented by serial selective coronary arteriography; 2) redistribution to the perfusion defect has been detected on the delayed image in myocardial imaging; 3) no coronary arterial lesions distal to the graft site have been detected by coronary angiography. When these three conditions are satisfied, at least one of the following conditions must apply: 1) Localized stenosis in the left main trunk has progressed to critical stenosis; 2) there is occlusion of two or more vessels; 3) collateral vessels connecting to the peripheral portion of an occluded coronary artery arise from the peripheral part of a vessel with progressive localized stenosis; 4) progressive localized stenosis or critical stenosis has developed in the left anterior descending artery, in addition to significant stenosis in the right coronary artery.

Histopathologic and ultrastructural observations of acute and convalescent myocarditis: a serial endomyocardial biopsy study

Serial endomyocardial biopsy findings were analyzed in ten cases with acute myocarditis of possible viral origin. The histopathologic findings were analyzed at the acute (0-10 days after the onset), subacute (11-21 days), and convalescent stages (22-167 days). The incidence and severity of various cardiac myocyte and interstitial changes were compared at each stage of the disease. The time-course changes of the histopathologic findings in acute myocarditis were as follows. At the acute stage, we observed: interstitial cell infiltration composed of fibroblasts, macrophages, and lymphocytes, fragmentation of the muscle bundles, myocytolytic changes, swelling and scarcity of the cytoplasm and swelling of nuclei, variation in size of the myocytes, disarrangement of the muscle bundles, interstitial edema, increased glycogen deposition in the myocytes, abnormal branching of the myocytes, and interstitial fibrosis. At the convalescent stage, most of the above findings could still be seen except for myocytolytic changes, swelling of myocytes, and interstitial edema. At the subacute and convalescent stages, an increase in abnormal branching and in double nuclei in the myocytes and nuclear degeneration became observable. A further control study comparing the changes at the convalescent stage of myocarditis and the myocardial changes in cases with chronic right ventricular overload in 58 cases revealed that in the former fragmentation of the muscle bundles, abnormal branching, size variation, glycogen deposition, and large mononuclear cell infiltrations were significantly more frequent. Ultrastructural observation of the myocytes revealed that they have a great potentiality for regeneration; myocytes showing severe myocytolytic changes may recover to regain an architecture of almost normal appearance.

Current problems in establishing quantitative histopathologic criteria for the diagnosis of lymphocytic myocarditis by endomyocardial biopsy

Both the clinical and the biopsy diagnoses of myocarditis are prone to false-positive and false-negative interpretations. False-positive clinical diagnoses probably most commonly result from a failure to recognize other disorders, such as cardiomyopathy and myocardial infarction, that may mimic myocarditis. False-negative clinical diagnoses may occur in patients with myocarditis in whom the signs and symptoms are atypical, absent, or misinterpreted. The two most common errors made by pathologists that produce false-positive tissue diagnoses appear to be a failure to recognize the number of lymphocytes that occupy the normal myocardial interstitium and a misinterpretation of noninflammatory interstitial cells as lymphocytes. Sampling error may be the most usual cause of false-negative tissue diagnoses. Since myocarditis is characterized by leukocytic and reparative responses, the most important features to evaluate in endomyocardial biopsy tissues are the type, distribution, and extent of the inflammatory infiltrate and the presence and extent of interstitial and endocardial fibrosis. Although no single histopathologic criterion is both sensitive and specific for myocarditis, it appears that quantitative evidence of an interstitial leukocytic infiltrate is currently the best available hallmark for myocarditis in biopsy specimens. It is suggested that a mean lymphocyte count greater than 5.0/high-power (X 400) microscopic field be considered indicative of lymphocytic myocarditis and that a mean count less than this be interpreted as myocarditis only if discrete clusters of lymphocytes are identified, since differentiation of low-grade diffuse infiltrates from expected normal lymphocytic populations is problematic at levels less than 5.0.

Endomyocardial biopsy: a review of the literature

A review of the literature relating to endomyocardial biopsy (EMB) is presented. This is considered important at this time since EMB is being utilized with increasing frequency, particularly for the diagnosis of myocarditis. The development of the technique is briefly outlined. Emphasis is placed on the clinical application of EMB in the various primary cardiomyopathies (dilated, hypertrophic, restrictive, and obliterative), the infiltrative secondary cardiomyopathies (amyloidosis, sarcoidosis, hemochromatosis), myocarditis, as well as such conditions as adriamycin cardiotoxicity, cardiac transplant rejection, and Kawasaki disease. More controversial application of EMB in primary mitral valve prolapse (Barlow's syndrome), idiopathic ventricular arrhythmias, and the elucidation of the enigmatic finding of angina with angiographically normal coronary arteries is detailed. Experience with immunological and biochemical investigation of biopsy material, as well as with virus isolation and drug assays in the myocardium, is alluded to. Complications encountered with this procedure are also discussed, and its future role is contemplated.

Kawasaki syndrome in an adult: endomyocardial histology and ventricular function during acute and recovery phases of illness

Kawasaki syndrome, an acute systemic inflammatory illness of unknown origin usually affecting children, may develop into a serious illness complicated by coronary artery aneurysms or myocarditis. This report describes an adult with Kawasaki syndrome studied by right ventricular endomyocardial biopsy and cardiac catheterization during the acute and recovery phases of illness. The initial biopsy specimen showed acute myocarditis and was associated with hemodynamic evidence of biventricular dysfunction, a severely depressed left ventricular ejection fraction and global hypokinesia. With time, there was spontaneous and rapid resolution of the inflammatory cell infiltrate with concurrent return to normal myocardial function. Right ventricular endomyocardial biopsy studies early in the course of the cardiac disease associated with Kawasaki syndrome may correlate with ventricular function and may be useful for monitoring immunosuppressive therapy in patients with this syndrome.

Fate of coronary aneurysms in Kawasaki disease: serial coronary angiography and long-term follow-up study

Between January 1973 and December 1979, 290 patients with Kawasaki disease were evaluated with coronary angiography after the acute stage of illness. Of these patients, 43 (15 percent) were diagnosed as having coronary aneurysms. Forty-two patients have been followed up for an average of 4 years (range 15 months to 8 years). One 8 month old girl died of myocardial infarction after 4 months of illness. Follow-up coronary angiography was performed in 42 patients 5 to 18 months after the acute illness. Four groups can be distinguished. Group I: In 21 (50 percent) of 42 patients angiography showed that the coronary aneurysms had regressed, so that no observable lesions were seen. During convalescence, electrocardiography, exercise stress testing and thallium scintigraphy were within normal limits. In the other 21 patients abnormal findings persisted on follow-up angiography. Group II: Ten patients showed persistent coronary aneurysms, although reduced in size. Group III: In seven patients the aneurysms had disappeared, but complete obstruction or marked stenosis of coronary arteries was found. Group IV: In four patients, irregularities of the coronary arterial wall without stenosis were seen. Among patients with abnormal angiographic findings myocardial infarction and mitral regurgitation were also seen. Early initiation of aspirin therapy aneurysms show regression on angiography in 1 or 2 years in about half of patients. The remaining patients are at risk for ischemic heart disease. Thus, Kawasaki disease should be considered an important cause of ischemic heart disease in children and a possible risk factor of premature coronary atherosclerosis.