Hemodynamic factors of thrombus formation in coronary aneurysms associated with Kawasaki disease

Kawasaki Disease-Associated Cytokine Storm Syndrome

Kawasaki disease (KD) is a hyperinflammatory syndrome manifesting as an acute systemic vasculitis characterized by fever, nonsuppurative conjunctival injection, rash, oral mucositis, extremity changes, and cervical lymphadenopathy. KD predominantly affects young children and shares clinical features and immunobiology with other hyperinflammation syndromes including systemic juvenile idiopathic arthritis (sJIA) and multisystem inflammatory syndrome in children (MIS-C). Cytokine storm syndrome (CSS) is an acute complication in ~2% of KD patients; however, the incidence is likely underestimated as many clinical and laboratory features of both diseases overlap. CSS should be entertained when a child with KD is unresponsive to IVIG therapy with recalcitrant fever. Early recognition and prompt institution of immunomodulatory treatment can substantially reduce the mortality and morbidity of CSS in KD. Given the known pathogenetic role of IL-1β in both syndromes, the early use of IL-1 blockers in refractory KD with CSS deserves consideration.

Effect of Beta Blockers on the Hemodynamics and Thrombotic Risk of Coronary Artery Aneurysms in Kawasaki Disease

This study aims to simulate beta blockers' (BB) effects on coronary artery aneurysms' (CAA) hemodynamics and thrombotic risk in Kawasaki disease (KD). BB are recommended in cases of large aneurysms due to their anti-ischemic effect. Coronary blood flow (CBF) was simulated in KD patient-specific CAA models using computational fluid dynamics. Hemodynamic indices that correlate with thrombotic risk were calculated following two possible responses to BB: (1) preserved coronary flow (third BB generation) and (2) reduction in coronary flow (first and second BB generations) at reduced heart rate. Following CBF reduction scenario, mean TAWSS and HOLMES significantly decreased compared to normal conditions, leading to a potential increase in thrombotic risk. Preserved CBF at lower heart rates, mimicking the response to vasodilating BBs, does not significantly affect local CAA hemodynamics compared with baseline, while achieving the desired anti-ischemic effects. Different BB generations lead to different hemodynamic responses in CAA.

Incidence and timing of coronary thrombosis in Kawasaki disease patients with giant coronary artery aneurysm

OBJECTIVE

Coronary thrombosis is a common cardiovascular complication of Kawasaki disease (KD), which seriously affects the long-term therapeutic effect of KD. The purpose was to determine the incidence and timing of coronary thrombosis and to identify risk factors for coronary thrombosis in KD with giant coronary artery aneurysm (GCAA).

METHODS AND RESULTS

A total of 94 consecutive KD patients with GCAA from Children's Hospital Affiliated to Chongqing Medical University were enrolled retrospectively. The cumulative incidence of coronary thrombosis in KD patients with GCAA was 59 % (n = 54). Coronary thrombosis mainly occurred in the acute phase (n = 41/54, 76 %), with a median time of 16 days after onset. Cox regression analysis was used to identify risk factors for coronary thrombosis. Cox regression analysis indicated that male (hazard ratios, 1.87; 95 % CI, 1.01-3.44; P = 0.43), left anterior descending artery (LAD) involvement (hazard ratios, 3.75; 95 % CI, 1.85-7.39; P < 0.001), coronary absolute diameter ≥ 8 mm (hazard ratios, 2.93; 95 % CI, 1.36-6.29; P = 0.006) constituted a higher risk of coronary thrombosis after adjusting for confounders. Kaplan-Meier method showed the cumulative incidence for coronary thrombosis in KD patients with GCAA was 79 %, 92 %, and 88 % in male, LAD involvement, coronary absolute diameter > 8 mm, respectively.

CONCLUSIONS

Male, LAD involvement, and coronary absolute diameter ≥ 8 mm were associated with a high incidence of coronary thrombosis. Based on the analysis of the incidence, time and risk factors of coronary thrombosis in different periods, this study may provide an essential reference for thromboprophylaxis management of KD with GCAA.

A practical nomogram for predicting coronary thrombosis for Kawasaki disease patients with medium or large coronary artery aneurysm

Kawasaki disease (KD) is the main cause of acquired heart disease in children. Coronary thrombosis is a serious cardiovascular complication of KD, which affects the long-term treatment effect. The purpose was to develop and validate a model for predicting coronary thrombosis in KD with medium or large coronary artery aneurysm (CAA). A total of 358 consecutive KD patients with medium or large CAA from Chongqing Children's Hospital were enrolled retrospectively. The demographic data, clinical characteristics, laboratory features before intravenous immunoglobulin (IVIG) treatment, and all radiological features during hospitalization and follow-up were collected. Eligible patients follow-up for > 2 years. Follow-up was weekly for the first 1 month, monthly for the next 11 months, and every 3-6 months after 1 year. The main examinations included echocardiogram and electrocardiogram. The primary endpoint was defined as coronary thrombosis during the follow-up. Coronary thrombosis was assessed by echocardiographic assessment of the presence of echoes in the lumen of the right coronary artery, left main coronary artery, left anterior descending artery, or left circumflex artery by echocardiologists. The independent risk factors were identified using univariate analyses and multivariate logistic regression analyses, and the nomogram was constructed for predicting coronary thrombosis. Tenfold cross-validation was used to perform internal validation. The area under the ROC curve (AUC), calibration curve, and decision curve analysis were used to evaluate the discrimination, calibration, and clinical utility of the nomogram, respectively. Multivariate logistic regression analysis revealed that male (odds ratio [OR] 3.491; 95% confidence interval [CI] 1.570-7.765), large CAA (OR 3.725; 95% CI 1.388-9.999), no use high-dose aspirin prior to IVIG (OR 3.114; 95% CI 1.291-7.510), two-vessel coronary artery involvement (OR 4.433; 95% CI 1.732-11.344), three-vessel coronary artery involvement (OR 5.417; 95% CI 2.048-14.328), four-vessel coronary artery involvement (OR 13.183; 95% CI 3.408-50.997), serum fibrinogen level > 5.325 g/L (OR 14.233; 95% CI 5.479-36.921), serum thrombin time level ≤ 15.15 s (OR 3.576; 95% CI 1.756-7.284) were significantly associated with coronary thrombosis. The nomogram was established based on these variables. The AUC of the nomogram were 0.920, and tenfold cross-validation (repeated 100 times) showed that the average AUC was 0.902. Moreover, the nomogram had a well-fitted calibration curve and also exhibited good clinical usage. The nomogram is based on six ready-made clinical variables, is easy to use, has excellent diagnostic performance, and can help clinicians make better clinical decisions on the management and treatment of KD patients with medium or large CAA.

Practical Workflow for Cardiovascular Assessment and Follow-Up in Kawasaki Disease Based on Expert Opinion

BACKGROUND

Approximately 25% of the patients with a history of Kawasaki disease (KD) develop coronary artery pathology if left untreated, with coronary artery aneurysms (CAA) as an early hallmark. Depending on the severity of CAAs, these patients are at risk of myocardial ischemia, infarction and sudden death. In order to reduce cardiac complications it is crucial to accurately identify patients with coronary artery pathology by an integrated cardiovascular program, tailored to the severity of the existing coronary artery pathology.

METHODS

The development of this practical workflow for the cardiovascular assessment of KD patients involve expert opinions of pediatric cardiologists, infectious disease specialists and radiology experts with clinical experience in a tertiary KD reference center of more than 1000 KD patients. Literature was analyzed and an overview of the currently most used guidelines is given.

CONCLUSIONS

We present a patient-specific step-by-step, integrated cardiovascular follow-up approach based on expert opinion of a multidisciplinary panel with expertise in KD.

Usefulness of oral anticoagulation in patients with coronary aneurysms: Insights from the CAAR registry

OBJECTIVES

To assess the Usefulness of oral anticoagulation therapy (OAT) in patients with coronary artery aneurysm (CAA).

BACKGROUND

Data on the most adequate antithrombotic CAA management is lacking.

METHODS

Patients included in CAAR (Coronary Artery Aneurysm Registry, Clinical Trials.gov: NCT02563626) were selected. Patients were divided in OAT and non-OAT groups, according to anticoagulation status at discharge and 2:1 propensity score matching with replacement was performed. The primary endpoint of the analysis was a composite and mutual exclusive endpoint of myocardial infarction, unstable angina (UA), and aneurysm thrombosis (coronary ischemic endpoint). Net adverse clinical events, major adverse cardiovascular events, their single components, cardiovascular death, re-hospitalizations for heart failure, stroke, aneurysm thrombosis, and bleeding were the secondary ones.

RESULTS

One thousand three hundred thirty-one patients were discharged without OAT and 211 with OAT. In the propensity-matched sample (390 patients in the non-OAT group, 195 patients in the OAT group), after 3 years of median follow-up (interquartile range 1-6 years), the rate of the primary endpoint (coronary ischemic endpoint) was significantly less in the OAT group as compared to non-OAT group (8.7 vs. 17.2%, respectively; p = .01), driven by a significant reduction in UA (4.6 vs. 10%, p < .01) and aneurysm thrombosis (0 vs. 3.1%, p = .03), along with a non-significant reduction in MI (4.1 vs. 7.7%, p = .13). A non-significant increase in bleedings, mainly BARC type 1 (55%), was found in the OAT-group (10.3% in the non-OAT vs. 6.2% in the OAT group, p = .08).

CONCLUSION

OAT decreases the composite endpoint of UA, myocardial infarction, and aneurysm thrombosis in patients with CAA, despite a non-significant higher risk of bleeding.

Bleeding risk associated with combination thromboprophylaxis therapy is low for patients with coronary artery aneurysms after Kawasaki disease

BACKGROUND

Kawasaki disease (KD) may lead to coronary artery aneurysms (CAA) with potential for thrombosis. We aimed to determine the bleeding risk during thromboprophylaxis regimens with dual and triple therapy.

METHODS

KD patients with medium to large CAAs receiving combination thromboprophylaxis therapy (dual or triple therapy with acetylsalicylic acid (ASA), clopidogrel, low molecular weight heparin (LMWH) or warfarin) were reviewed (1979-2017). Treatment periods <30 days were excluded. Bleeding events were classified using the Bleeding Academic Research Consortium (BARC) Score. The incidence of bleeding events per patient year of exposure was determined for each regimen.

RESULTS

n = 98 of 3022 KD (23 females:75 males) were included. Median age at diagnosis was 2.6 years (IQR: 0.6-6.2), median maximum CAA z-score was 18.0 (range: 5-65.5, IQR: 10.8-28.0, m = 6) and median follow-up duration was 6.5 years (IQR: 2.5-20.2). The incidence of type ≥2 bleeds per patient-year for each regimen was 0 (ASA + clopidogrel+LMWH), 0.03 (ASA + clopidogrel), 0.06 (ASA + warfarin), 0.06 (ASA + clopidogrel+warfarin), and 0.1 (ASA + LMWH) in ascending order. 31 bleeding events requiring medical attention (type ≥2) occurred in 30 patients (median age 7.8 years). Of the 17 type ≥2 bleeds on warfarin with an International Normalised Ratio (INR) available, 13 occurred with an INR >3. For patients receiving triple therapy (dual antiplatelet with anticoagulant), there were 57 bleeding events over 20 treatment periods.

CONCLUSIONS

The overall bleeding risk was low in KD patients receiving combination thromboprophylaxis, and not significantly different across all regimens. Type ≥2 bleeding events that occurred on warfarin were most frequently associated with high INR values.

Medium-Term Complications Associated With Coronary Artery Aneurysms After Kawasaki Disease: A Study From the International Kawasaki Disease Registry

Background

Coronary artery aneurysms (CAAs) may occur after Kawasaki disease (KD) and lead to important morbidity and mortality. As CAA in patients with KD are rare and heterogeneous lesions, prognostication and risk stratification are difficult. We sought to derive the cumulative risk and associated factors for cardiovascular complications in patients with CAAs after KD.

Methods and Results

A 34‐institution international registry of 1651 patients with KD who had CAAs (maximum CAA Z score ≥2.5) was used. Time‐to‐event analyses were performed using the Kaplan–Meier method and Cox proportional hazard models for risk factor analysis. In patients with CAA Z scores ≥10, the cumulative incidence of luminal narrowing (>50% of lumen diameter), coronary artery thrombosis, and composite major adverse cardiovascular complications at 10 years was 20±3%, 18±2%, and 14±2%, respectively. No complications were observed in patients with a CAA Z score <10. Higher CAA Z score and a greater number of coronary artery branches affected were associated with increased risk of all types of complications. At 10 years, normalization of luminal diameter was noted in 99±4% of patients with small (2.5≤Z<5.0), 92±1% with medium (5.0≤Z<10), and 57±3% with large CAAs (Z≥10). CAAs in the left anterior descending and circumflex coronary artery branches were more likely to normalize. Risk factor analysis of coronary artery branch level outcomes was performed with a total of 893 affected branches with Z score ≥10 in 440 patients. In multivariable regression models, hazards of luminal narrowing and thrombosis were higher for patients with CAAs of the right coronary artery and left anterior descending branches, those with CAAs that had complex architecture (other than isolated aneurysms), and those with CAAs with Z scores ≥20.

Conclusions

For patients with CAA after KD, medium‐term risk of complications is confined to those with maximum CAA Z scores ≥10. Further risk stratification and close follow‐up, including advanced imaging, in patients with large CAAs is warranted.

HEMODYNAMIC STUDY OF CORONARY ARTERY ANEURYSMS

Background: When the coronary artery expands more than two times its diameter, it will form a coronary artery aneurysm (CAA). CAA can lead to myocardial ischemia. In this paper, the mechanism of myocardial ischemia induced by CAA was studied by geometric multiscale method. Methods: Four kinds of three-dimensional models of CAA with different dilation diameters were established on the basis of normal three-dimensional models. The dilation diameters were 2, 3, 5 and 7 times, capacitance was added after the CAA to simulate the elasticity of the vascular wall. Results:A large number of eddies exist in CAA. 2–7 times model: 1.1–14.4% reduction of blood flow downstream of CAA and 5, 7 times model showed upstream diastolic backward flow, the backward flow rate was 1.1% and 5.6%, respectively. The aveWSS at the CAA was 1.76–0.35[Formula: see text]Pa; the relative retention time was 1.1–14.6[Formula: see text]Pa[Formula: see text]; the average vorticity was 0.0085–231.7[Formula: see text]s[Formula: see text]. Conclusion:CAA can store blood, and the elasticity of the wall of CAA results in the flow of blood upstream. These two reasons make the downstream flow of CAA decrease and easily form intratumoral thrombosis, which may lead to myocardial ischemia.

Hemodynamic variables in aneurysms are associated with thrombotic risk in children with Kawasaki disease

BACKGROUND

Thrombosis is a major adverse outcome associated with coronary artery aneurysms (CAAs) resulting from Kawasaki disease (KD). Clinical guidelines recommend initiation of anticoagulation therapy with maximum CAA diameter (D_max) ≥8 mm or Z-score ≥ 10. Here, we investigate the role of aneurysm hemodynamics as a superior method for thrombotic risk stratification in KD patients.

METHODS AND RESULTS

We retrospectively studied ten KD patients with CAAs, including five patients who developed thrombosis. We constructed patient-specific anatomic models from cardiac magnetic resonance images and performed computational hemodynamic simulations using SimVascular. Our simulations incorporated pulsatile flow, deformable arterial walls and boundary conditions automatically tuned to match patient-specific arterial pressure and cardiac output. From simulation results, we derived local hemodynamic variables including time-averaged wall shear stress (TAWSS), low wall shear stress exposure, and oscillatory shear index (OSI). Local TAWSS was significantly lower in CAAs that developed thrombosis (1.2 ± 0.94 vs. 7.28 ± 9.77 dynes/cm², p = 0.006) and the fraction of CAA surface area exposed to low wall shear stress was larger (0.69 ± 0.17 vs. 0.25 ± 0.26%, p = 0.005). Similarly, longer residence times were obtained in branches where thrombosis was confirmed (9.07 ± 6.26 vs. 2.05 ± 2.91 cycles, p = 0.004). No significant differences were found for OSI or anatomical measurements such us D_max and Z-score. Assessment of thrombotic risk according to hemodynamic variables had higher sensitivity and specificity compared to standard clinical metrics (D_max, Z-score).

CONCLUSIONS

Hemodynamic variables can be obtained non-invasively via simulation and may provide improved thrombotic risk stratification compared to current diameter-based metrics, facilitating long-term clinical management of KD patients with persistent CAAs.

Coronary artery aneurysm regression after Kawasaki disease and associated risk factors: a 3-year follow-up study in East China

Kawasaki disease (KD) is the leading cause of acquired heart disease due to its complicated coronary artery lesions. Up to now, few studies were focused on the status of persistent coronary artery aneurysms (CAA) in KD patients. The present study was designed to identify the coronary artery outcomes and seek the risk factors associated with the regression of CAA in KD patients. One hundred and twenty KD patients with CAA hospitalized in Children's Hospital of Soochow University from Jan 2008 to Dec 2013 were prospectively studied by a 3-year follow-up. Data regarding demographic, clinical, laboratory, and echocardiographic characteristics were documented and further analyzed. It was estimated that 39.2% of the patients had complete regression of CAA within 4 weeks, 59.2% within 8 weeks, and 70.0% within 16 weeks. No fatal cardiac events occurred. We found patients who aged ≤ 1 year, received initial intravenous immunoglobulin (IVIG) treatment after the 10th day of illness, and IVIG non-responders were associated with the regression of persistent CAA. The relative risks were 1.55, 1.87, and 1.88, respectively. Age, initial IVIG treatment, and IVIG response were risk factors of persistent CAA, and more attention should be paid on these patients.

Review: surgical treatment of giant coronary aneurysms in pediatric patients with Kawasaki disease

In Kawasaki disease (KD), giant coronary aneurysms in the proximal segments of the coronary arteries have long been among the serious complications associated with acute myocardial infarction. To treat myocardial ischemia in children, Kitamura et al. first performed coronary artery bypass grafting in a pediatric patient using an autologous saphenous vein. In the early 1980s, they began to use the internal thoracic artery (ITA) as a bypass graft to the left anterior descending artery, which later was proven to improve long-term life expectancy with its favorable long-term patency, as well as growth potential. Thus, the excellent characteristics of the ITA have come to be widely known among pediatric cardiac surgeons, and a growing number of coronary bypass surgery procedures using the ITA are now being performed worldwide. Although a longer follow-up with more patients is necessary, downsizing reconstructive procedure may be a treatment of choice for giant aneurysms of non-LAD territories to improve coronary circulation. The efficacy of surgical treatment for giant coronary aneurysms in pediatric patients with Kawasaki disease is now well established. Pediatric coronary artery bypass grafting using the ITA, either single or bilateral, can be safe not only for patients with Kawasaki coronary disease but also for infants with congenital coronary lesions.

Coronary artery ectasia presenting with acute inferior wall myocardial infarction in a young adult

Coronary artery ectasia (CAE), a variant of coronary artery anomalies, is a rare clinical entity. Although atherosclerotic coronary artery disease (CAD) is the most common cause of acute coronary syndrome (ACS), CAE also conveys a relatively high risk for potentially life-threatening cardiac events. We report a case of a 35-year-old male with two-vessel CAE, who presented with acute inferior wall ST election myocardial infarction (STEMI). After initiating medical therapy including bivalirudin, emergent percutaneous coronary intervention (PCI) with stenting of postero-lateral branch of right coronary artery (RCA) was performed. Coronary angiography also showed diffuse ectasia of RCA and left anterior descending artery (LAD). The patient tolerated the procedure well and was discharged on appropriate medical therapy. He was followed-up at one month, with no resulting cardiac events. This case highlights the importance of CAE awareness. CAE has drawn the attention of clinicians because of its clinical implications, as well as its seemingly higher prevalence, due to the abundant use of coronary angiograms and advanced cardiac imaging in the contemporary world. Albeit there has been much progress in the understanding and management of the disease, questions still remain regarding the exact pathophysiology, management guidelines and prognosis of CAE, which are worth further study.

Assessment of Coronary Artery Aneurysms Caused by Kawasaki Disease Using Transluminal Attenuation Gradient Analysis of Computerized Tomography Angiograms

Patients with coronary artery aneurysms (CAAs) resulting from Kawasaki disease (KD) are at risk for thrombosis and myocardial infarction. Current guidelines recommend CAA diameter ≥8 mm as the criterion for initiating systemic anticoagulation. Transluminal attenuation gradient (TAG) analysis has been proposed as a noninvasive method for evaluating functional significance of coronary stenoses using computerized tomography angiography (CTA), but has not previously been used in CAA. We hypothesized that abnormal hemodynamics in CAA caused by KD could be quantified using TAG analysis. We studied 23 patients with a history of KD who had undergone clinically indicated CTA. We quantified TAG in the major coronary arteries and aneurysm geometry was characterized using maximum diameter, aneurysm shape index, and sphericity index. A total of 55 coronary arteries were analyzed, 25 of which had at least 1 aneurysmal region. TAG in aneurysmal arteries was significantly lower than in normal arteries (-23.5 ± 10.7 vs -10.5 ± 9.0, p = 0.00002). Aneurysm diameter, aneurysm shape index, and sphericity index were weakly correlated with TAG (r² = 0.01, p = 0.6; r² = 0.15, p = 0.06; r² = 0.16, p = 0.04). This is the first application of TAG analysis to CAA caused by KD, and demonstrates significantly different TAG values in aneurysmal versus normal arteries. Lack of correlation between TAG and CAA geometry suggests that TAG may provide hemodynamic information not available from anatomy alone. TAG represents a possible extension to standard CTA for KD patients who may improve thrombotic risk stratification and aid in clinical decision making.

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.

Role of TGF-β Signaling in Remodeling of Noncoronary Artery Aneurysms in Kawasaki Disease

Coronary artery aneurysms (CAA) remain an important complication of Kawasaki disease (KD), the most common form of pediatric acquired heart disease in developed countries. Potentially life-threatening CAA develop in 25% of untreated children and 5% of children treated with high-dose intravenous immunoglobulin during the acute phase of the self-limited vasculitis. Noncoronary artery aneurysms (NCAA) in extraparenchymal, muscular arteries occur in a minority of patients with KD who also have CAA, yet little is understood about their formation and remodeling. We postulated that activation of the transforming growth factor-β (TGF-β) pathway in KD may influence formation and remodeling of aneurysms in iliac, femoral, and axillary arteries, the most common sites for NCAA. We studied a resected axillary artery from one adult and endarterectomy tissue from the femoral artery from a second adult, both with a history of CAA and NCAA following KD in infancy. Histology of the axillary artery aneurysm revealed destruction of the internal elastic lamina and recanalization of organized thrombus, while the endarterectomy specimen showed dense calcification and luminal myofibroblastic proliferation. Immunohistochemistry for molecules in the TGF-β signaling pathway revealed increased expression of TGF-β2, TGF-β receptor 2, and phosphorylated SMAD3. These findings suggest ongoing tissue remodeling of the aneurysms decades after the acute injury and demonstrate the importance of the TGF-β signaling pathway in this process.

Low-dose antithrombotic treatment in coronary thrombosis of Kawasaki disease

To explore effective and convenient rescue therapy options for coronary artery aneurysms (CAA) with thrombosis in Kawasaki disease (KD). A total of 210 patients with KD between the years 2003 and 2013 were retrospectively reviewed in our institute. 144 of these 210 KD developed CAA, and 10 patients with CAA had associated thrombosis. Thrombosis was confirmed by two-dimensional echocardiograms (2-DE). Laboratory values for CAA were analyzed with and without the thrombus group. The characteristics of CAA were monitored by ultrasound. All patients with thrombus received intravenous (IV) antithrombotic therapy, including urokinase, heparin, and oral warfarin. The effectiveness of antithrombotic treatment was evaluated by measuring the ability to dissolve the thrombus. All thrombi in these patients were preceded by a giant CAA and a history of KD. There are no differences in the blood analyses of both CAA with and without thrombus. Moreover, typical KD symptoms and acute myocardial infarction were not found in CAA with thrombosis. The progression of coronary thrombosis in these patients was arrested by antithrombotic and anti-platelet treatment including low-dose urokinase and heparin. Neither clinical features nor laboratory data could reliably predict CAA associated thrombosis. Therapy with IV anti-thrombus and anti-platelet treatment with low-dose warfarin can effectively dissolve thrombi in KD patients.

Two cases of super-giant coronary aneurysms after kawasaki disease

Acute giant coronary aneurysm after Kawasaki disease (KD) is a catastrophic complication that can be fatal and very difficult to manage. However, no fixed consensus has been reached for the management of super-giant coronary aneurysms in the acute setting. Here, we report the successful management of young children with super-giant coronary aneurysms after KD. Based on our experience, hemodynamic stabilization to prevent further coronary dilation or rupture and strict anticoagulation to avoid thrombus formation are mandatory in the management of this condition.

National Japanese survey of thrombolytic therapy selection for coronary aneurysm: intracoronary thrombolysis or intravenous coronary thrombolysis in patients with Kawasaki disease

BACKGROUND

Thrombolytic therapy for coronary aneurysm thrombosis of Kawasaki disease (KD) includes antiplatelet and anticoagulants, i.v. coronary thrombolysis (IVCT), and i.c. thrombolysis (ICT). Therapeutic methods, drugs and doses vary among medical facilities.

METHODS AND RESULTS

A nationwide survey of thrombolytic therapy was conducted under the auspices of the Ministry of Health, Labour and Welfare Research Program to Intractable Diseases Research Grants. A secondary survey targeted 14 facilities conducting thrombolytic therapy during a 5 year period (2004-2009). The primary survey investigated performance of thrombolytic therapy for 23 KD patients at 14 facilities, and of these, five with acute myocardial infarction had received ICT and combined therapy. The secondary survey investigated the pre-treatment condition of aneurysm and thrombosis and actual treatment methods. ICT was effective for small thrombi (≤ 10 mm), while IVCT was effective even for giant thrombi (>10 mm). ICT was also effective for thrombi within several hours after formation.

CONCLUSION

In the present nationwide survey, thrombolytic therapy was more effective in cases of a shorter duration between thrombus formation and the start of treatment. It was found that many facilities used only IVCT for thrombus alone. Medications given to KD children did not cause serious hemorrhagic complications, unlike in adults. Although doses exceeded recommended levels in many cases, the only complications were nasal bleeding and fever.

Natriuretic Peptides in Kawasaki Disease: the Myocardial Perspective

Making a diagnosis of Kawasaki disease with certainty may be challenging, especially since the recognition of cases with incomplete diagnostic criteria and its consequences. In order to build the diagnostic case in daily practice, clinicians rely on clinical criteria established over four decades ago, aided by non specific laboratory tests, and above all inspired by experience. We have recently studied the diagnostic value of N-terminal pro B-type natriuretic peptide to improve the diagnostic certainty of cases with complete or incomplete clinical criteria. Our working hypothesis was based on the fact that myocarditis is present in nearly all Kawasaki disease patients supported by histology data. In this paper, we review these facts and the myocardial perspective from the diagnostic and the mechanistic standpoints.

Long-term anticoagulation in Kawasaki disease: Initial use of low molecular weight heparin is a viable option for patients with severe coronary artery abnormalities

Patients with severe coronary artery involvement after Kawasaki disease (KD) require long-term systemic anticoagulation. We sought to compare our experience with thrombotic coronary artery occlusions, safety profile, and degree of coronary artery aneurysm regression in KD patients treated with low molecular weight heparin (LMWH) versus warfarin. Medical records of all KD patients diagnosed between January 1990 and April 2007 were reviewed. Of 1374 KD patients, 38 (3%) received systemic anticoagulation, 25 patients received LMWH from diagnosis onward, 12 of whom were subsequently switched to warfarin, and 13 received warfarin from onset. The frequency of thrombotic coronary artery occlusions was similar between drugs. Severe bleeding was more frequent in patients on warfarin, but minor bleeding was more frequent for patients on LMWH. Patients on warfarin were at greater risk of underanticoagulation or overanticoagulation (defined as achieving an anti-activated factor X level or an international normalized ratio below or above target level) than patients on LMWH (P < 0.05). Maximum coronary artery aneurysm z-scores diminished with time for patients on LMWH (P = 0.03) but not for those on warfarin (P = 0.55). This study suggests that LMWH is a potentially viable alternative for patients, especially young ones, with severe coronary artery involvement after KD.

Improved classification of coronary artery abnormalities based only on coronary artery z-scores after Kawasaki disease

Competing definitions and classifications of coronary artery abnormalities (CAAs) after Kawasaki disease (KD) have been arbitrarily defined based on clinical experience. We sought to propose a classification system for CAAs based only on coronary artery z-scores. All echocardiograms performed between 1990 and 2007 on patients with a previous history of KD were reviewed. Coronary artery luminal dimensions were converted to body-surface-area-adjusted z-scores and compared to current classification systems. A total of 1356 patients with a previous history of KD underwent 4379 echocardiograms. There was important overlap in the distributions of coronary artery z-scores between the different CAA classes as defined by the American Heart Association (AHA). The AHA classification underestimated the severity of CAAs in 19-32% of small CAAs and 35-78% of medium CAAs. We determined the optimal definition of CAA to be small if the z-score is >or=2.5 to <5.0, large if the z-score is >or=5.0 to <10.0, and giant if the z-score is >or=10.0. This classification seems to appropriately apply to the circumflex branch despite a lack of normal values for this branch. The current AHA classification might not accurately classify CAAs in KD patients. Accurate classification is important for defining management and prognosis consistently across patient age and size.

Comparison of factors associated with coronary artery dilation only versus coronary artery aneurysms in patients with Kawasaki disease

We sought to determine whether differences exist in the factors associated with transient coronary artery (CA) dilation only compared to CA aneurysms after Kawasaki disease (KD). We reviewed all patients with KD assessed and treated at a single tertiary institution from January 1990 to April 2007. Of 1,374 patients (63% men) with KD, 1,108 (81%) had no CA abnormalities; 180 (13%) had CA dilation only, and 86 (6%) had CA aneurysms. The factors associated with any CA abnormality included male gender (odds ratio [OR] 1.8, p <0.001), lower albumin (OR per 1 g/dl, 1.07; p < 0.001), lower hemoglobin (OR per 10 g/dl; 1.02, p = 0.008), diagnosed outside of the 1 to 9-year-age range (OR for <1 year old, 1.5; p = 0.04; OR for >9 years old, 1.9, p = 0.03), longer duration of fever before treatment (OR per day, 1.05, p = 0.002), greater platelet count (OR per 10 x 10(9)/L, 1.14, p = 0.008), and nonresponse to initial intravenous immunoglobulin treatment (OR 2.4, p <0.001). Only age at diagnosis, duration of fever before treatment, greater platelet count, and nonresponse to initial intravenous immunoglobulin discriminated between CA dilation only versus CA aneurysms (c-statistic, 0.80, p <0.001). In conclusion, CA dilation only and CA aneurysms differ only in the total duration of inflammation, as measured by the number of days from fever onset to defervescence.

Thrombus in a coronary artery aneurysm shortly after warfarin withdrawal

This report describes the rapid buildup of an intraluminal thrombus and secondary myocardial ischemia after a brief therapeutic withdrawal of warfarin in a case of Kawasaki-related chronic giant coronary aneurysm. The importance of tight antithrombotic control in such cases is underscored.

Coronary artery aneurysm induced by Kawasaki disease in children show features typical senescence

BACKGROUND

Kawasaki disease (KD) causes coronary artery disease (CAD) in children. In addition, a history of KD is suspected to be a risk factor for the development of atherosclerotic heart disease in the future. Histological senescence changes are a common denominator in atherosclerotic lesions in adults, so the present study investigated whether histological senescence changes had already occurred in KD aneurysm.

METHODS AND RESULTS

KD coronary aneurysms and internal mammary arteries retrieved from 5 children with KD (3, 4, 5, 6, and 11 years old, respectively) who underwent coronary artery bypass grafting, as well as giant coronary aneurysm size-reducing operations, were analyzed. Senescence-associated strong beta-galactosidase activity was observed in KD aneurysms, but not in the internal mammary arteries. An immunohistochemical analysis of the KD aneurysm using anti-CD31, anti-endothelial nitric oxide synthetase (eNOS), anti-vascular adhesion molecule-1 (VCAM-1), and anti-monocyte chemoattractant protein-1 (MCP-1) showed vascular endothelium CD31 staining, decreased staining of eNOS and strong staining of MCP-1 and VCAM-1. cDNA microarray gene expression profiling revealed increased MCP-1 expression in the KD aneurysm, a finding confirmed by quantitative polymerase chain reaction.

CONCLUSIONS

Histological features of senescence and active remodeling gene expression show that the KD aneurysm is not a silent vasculitis terminal. The future fate of KD aneurysms, including atherosclerosis, should be monitored carefully.

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.

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 syndrome

Kawasaki syndrome is an acute, self-limited vasculitis that occurs in children of all ages and presents a challenge for the clinician: the disorder can be difficult to recognise; there is no diagnostic laboratory test; there is an extremely effective therapy; and there is a 25% chance of serious cardiovascular damage if the treatment is not given early in the course of the disease. This review includes discussion of the history of the syndrome, the diagnostic challenges, epidemiology, aetiology, pathology, immunopathogenesis, therapy, genetic influences, and the long-term cardiovascular sequelae.

Optimal Time of Surgical Treatment for Kawasaki Coronary Artery Disease

BACKGROUND

The major complication of Kawasaki coronary disease is myocardial infarction caused by thrombus formation inside the aneurysm or by organic obstructive lesion following the regression of aneurysm, while the indications for surgical therapy remain controversial. We have adopted coronary artery bypass grafting (CABG) even in young children for giant coronary aneurysms (more than 8 mm diameter) with or without a stenotic region when myocardial ischemia is detected. We hypothesized that a shorter time-period from diagnosis of acute Kawasaki disease (KD) to CABG would lead to better postoperative results. To elucidate the validity of our strategy, we evaluated preoperative patient characteristics and long-term outcome.

METHODS

Twenty-one patients (mean age: 12.0 years old) with Kawasaki coronary disease had undergone CABG during the last 12 years. The mean age at the time of acute KD was 2.7 years and the mean time range from diagnosis of acute KD to CABG was 8.1 years. The incidence of preoperative reduced ventricular function was 10 per 21 patients (47.6%). A multivariate logistic regression analysis using patient characteristics showed that the time range from acute KD to CABG was the only predictor for ventricular functional deterioration (p=0.03, odds ratio 1.55. 95%CI: 1.033 approximately 2.325). Based on these results, we divided the patients into two groups of short time range (mean: 3.7 years; group S) and long time range (mean: 13.9 years; group L).

RESULTS

Preoperative left ventricular functional deterioration was recognized more frequently in group L (9/9, 100%) than in group S (1/12, 8.3%)(p<0.01). Myocardial infarction was documented significantly higher in the group L (6/9, 66.7%) than group S (1/12, 8.3%)(p=0.04). There was no surgical mortality in either group. The arterial grafts demonstrated good potential for growth and graft patency was 96.9%. Moreover, seven of the giant aneurysms proximal to the graft anastomosis showed complete thrombotic occlusion after CABG without development of myocardial infarction. The cardiac events free rate of group L and group S was 66.7% and 100%, respectively, during the postoperative follow up periods of 5.5+/-1.1 years (group L) and 4.7+/-1.1 years (group S).

CONCLUSIONS

We successfully applied CABG for Kawasaki coronary disease. Based on our experience, a short interval after acute KD appears to be ideal for surgical treatment of Kawasaki coronary disease.

Spontaneous platelet aggregation in Kawasaki disease using the particle counting method

BACKGROUND

Platelet aggregation is generally measured by the optical density method. This method is not very sensitive in detecting platelet activation because of the poor correlation between the formation of platelet aggregates and light transmission, and inability to detect small platelet aggregates. Recently, a new method was developed that detects small platelet aggregates formed in the early phase of platelet aggregation by means of a particle counting technique using light scattering.

METHODS

The present study used the particle counting method to measure spontaneous platelet aggregation (SPA) produced by agitation with a stirrer bar without agonists in patients with Kawasaki disease (KD) and children's thrombotic disease, and compared the results with the conventional optical density method.

RESULTS

Using the particle counting method, significantly higher SPA rates were found before treatment than in healthy adults and at the other stages of treatment. A similar tendency was noted with the optical density method; however, the positive rate of SPA was significantly higher with the particle counting method in each stage except the second stage, which was the period from the start of gamma-globulin therapy to 20 days.

CONCLUSION

These results indicate that enhanced platelet aggregation is noted at a high frequency before treatment of KD and that the particle counting method is superior to the optical density method in detecting enhanced platelet aggregation.