Safety and Efficacy of Warfarin Therapy in Kawasaki Disease

In vitro evaluation of global coagulation potential of emicizumab and warfarin using rotational thromboelastometry

Warfarin inhibits the generation of vitamin K-dependent proteins and emicizumab can prevent bleeding episodes in people with hemophilia A (PwHA), but their combined hemostatic potential remains unclear. We analyzed the coagulation potential of emicizumab combined with warfarin in a simulated model of PwHA. Nineteen samples were collected from ten patients taking warfarin, and the prothrombin time-international normalized ratio (PT-INR) was used to define near-normal (INR 1.2-1.48; n = 4), subtherapeutic (INR 1.56-1.9; n = 7) and therapeutic (INR > 2.0; n = 8) groups. Factor (F)VIII activity (FVIII:C) was neutralized using an anti-FVIII inhibitor antibody (termed FVIII-depleted) before the addition of emicizumab (50 µg/mL). Coagulation potential was measured using Ca2 + -triggered rotational thromboelastometry, and was compared with that in emicizumab-treated PwHA. The average PT-INR in the near-normal, subtherapeutic, and therapeutic groups was 1.3 ± 0.1, 1.7 ± 0.1, and 2.4 ± 0.3, respectively. The hemostatic potential in FVIII-depleted samples mixed with emicizumab in the near-normal group was comparable to that in emicizumab-treated PwHA. The coagulation potential in FVIII-depleted samples after addition of emicizumab in the subtherapeutic and therapeutic groups were lower than that in emicizumab-treated PwHA. PT-INR monitoring could be informative in emicizumab-treated PwHA due to the influence of vitamin K-dependent proteins.

Update on Diagnosis and Management of Kawasaki Disease: A Scientific Statement From the American Heart Association

Kawasaki disease (KD), an acute self-limited febrile illness that primarily affects children <5 years old, is the leading cause of acquired heart disease in developed countries, with the potential of leading to coronary artery dilation and coronary artery aneurysms in 25% of untreated patients. This update summarizes relevant clinical data published since the 2017 American Heart Association scientific statement on KD related to diagnosis, cardiac imaging in acute KD treatment, and long-term management. Criteria defining North American patients at high risk for developing coronary artery aneurysms who may benefit from more intensive initial treatment have been published. Advances in cardiovascular imaging have improved the ability to identify coronary artery stenosis in patients with KD, yet knowledge gaps remain regarding optimal frequency of serial imaging and the best imaging modality to identify those at risk for inducible myocardial ischemia. Recent data have advanced the understanding of safety and dosing for several anti-inflammatory therapies in KD. New anticoagulation medication, myocardial infarction management, transition of health care for patients with KD, and future directions in research are discussed.

Refractory Kawasaki Disease With a Giant Aneurysm Successfully Treated With Infliximab and Enoxaparin: A Case Report

Kawasaki disease (KD) is the most common vasculitis in children, and can result in the development of coronary artery aneurysms (CAAs) if not properly managed. While intravenous immunoglobulin (IVIG) and aspirin are standard first-line treatments, refractory KD may develop, increasing the risk of coronary complications. Herein, we report the case of a young girl with KD who initially responded to IVIG, but later developed a giant CAA, despite additional treatments. Infliximab stabilized her condition, and one year later, the CAA remained stable without thrombus formation. This case demonstrates that clinical appearance, particularly fever, may not fully reflect the patient's condition, as fever can subside immediately after treatment, but may relapse days later, underscoring the need for vigilant monitoring.

Real-world experience with edoxaban for anticoagulation in children at risk for coronary artery thrombosis

BACKGROUND

Direct oral anticoagulants have the potential to improve care in children requiring chronic anticoagulation. Edoxaban has favourable pharmacokinetics that could benefit younger patients but data on long-term safety and efficacy for specific paediatric indications are lacking.

STUDY AIMS

We present a single-centre experience using edoxaban in children who require chronic anticoagulation for large coronary artery aneurysms secondary to Kawasaki disease.

METHODS

Weight-based dosing of once-daily oral edoxaban was offered as alternative to standard anticoagulation for patients aged 1-18 years. Chart review was performed for a median follow-up period of 49 months on edoxaban. Steady-state pharmacokinetics and pharmacodynamics of edoxaban were also explored.

RESULTS

Sixteen patients on chronic therapy with edoxaban were included. No major bleeding events were reported. Two patients experienced coronary artery thrombosis after 23 and 38 months on edoxaban, 7 and 11 years after diagnosed with Kawasaki disease, respectively. This predicts 70% event-free rate at 12 years from diagnosis. Area under the curve estimates over the dosing interval of 24 hours were similar to those reported in adults.

CONCLUSIONS

Edoxaban use is feasible and well-tolerated for long-term use in paediatric population. We suggest appropriate exposure using weight-based once-daily dosing strategy that may be comparable to standard-of-care anticoagulation in prevention of coronary artery thrombosis. Larger studies are needed to evaluate long-term safety and efficacy of edoxaban in this population.

Risk factors for serious adverse events related to vitamin K antagonists in children with congenital or acquired heart disease: a prospective cohort study

OBJECTIVES

To assess the occurrence of thrombosis and major bleeding in children with congenital or acquired heart disease (CAHD) treated with VKA and to identify risk factors for these serious adverse events (SAE).

STUDY DESIGN

All children enrolled in our VKA dedicated educational program between 2008 and 2022 were prospectively included. The time in therapeutic range (TTR) was calculated to evaluate the stability of anticoagulation. Statistical analysis included Cox proportional hazard models.

RESULTS

We included 405 patients. Median follow-up was 18.7 (9.3-49.4) months. The median TTR was 83.1 % (74.4 %-95.3 %). No deaths occurred because of bleeding or thrombotic events. The incidences of thrombotic and major bleeding events were 0.9 % (CI95 % [0.1-1.8]) and 2.3 % (CI95 % [0.9-3.8]) per patient year, respectively. At 1 and 5 years, 98.3 % (CI95 % [96.2 %-99.2 %]) and 88.7 % (CI95 % [81.9 % 93.1 %]) of patients were free of any SAE, respectively. Although the mechanical mitral valve (MMV) was associated to major bleeding events (HR = 3.1 CI95 % [1.2-8.2], p = 0.02) in univariate analysis, only recurrent minor bleeding events (HR = 4.3 CI95 % [1.6-11.7], p < 0.01) and global TTR under 70 % (HR = 4.7 CI95 % [1.5-15.1], p < 0.01) were independent risk factors in multivariable analysis. In multivariable analysis, giant coronary aneurysms after Kawasaki disease (HR = 7.8 [1.9-32.0], p = 0.005) was the only risk factor for thrombotic events.

CONCLUSION

Overall, VKA therapy appears to be safe in children with CAHD. Suboptimal TTR, regardless of the indication for VKA initiation, was associated with bleeding events.

A registry study of Kawasaki disease patients with coronary artery aneurysms (KIDCAR): a report on a multicenter prospective registry study three years after commencement

The long-term prognosis of patients with Kawasaki disease (KD) complicated by coronary artery aneurysms (CAA) is still unclear. The present, multicenter registry study aimed to study the factors associated with coronary events (CE) and determine an appropriate management method for patients with KD complicated with CAA. Patients with KD with onset after 2015 and with a medium-sized or large CAA having an actual diameter ≥ 4 mm or a Z-score ≥ 5.0 at 30 days and later after KD onset were included in the annual survey. The primary endpoint was the time-dependent incidence of CE. Associated factors were also examined. In total, 179 patients from 53 centers were enrolled and followed up for a median of 501 days. The median age at KD onset was 2.2 years, 137 patients were male (77%), 47 had incomplete KD (26%), and 36 had large CAA (20%). CE occurred in 13 patients (7%; 95% confidence interval: 4-12%); eight (62%) experienced CE within 1 year, and all the patients experienced a CE within 2 years. All but one patient received antiplatelet drugs and warfarin. Patients with a large CAA had significantly more CAA (2.8 vs. 1.7, p < 0.001), more cases of warfarin use (86% vs. 43%, p < 0.001), and were more likely to have CE (28% vs. 2%, p < 0.001) than those with a medium-sized CAA. On univariate Cox regression analysis, the factors significantly associated with CE were large CAA (hazard ratio (HR): 17.0), three or more CAA (HR: 23.3), and beaded CAA (HR: 15.9). Multivariable Cox regression analysis revealed that the only associated factor was a large CAA.

CONCLUSION

Patients with a large CAA were more likely to have a CE within 2 years. Antithrombotic therapy with warfarin did not eliminate the CE risk, and better therapies are desirable.

WHAT IS KNOWN

• Coronary artery aneurysms are a serious complication of Kawasaki disease, and coronary events are sometimes fatal. • In previous, retrospective studies in Japan, large aneurysms, male sex, and refractoriness to initial immunoglobulin therapy were considered risk factors for coronary events.

WHAT IS NEW

• Of 179 patients with a medium sized or large aneurysm, 13 (7%) experienced coronary events, all of which occurred within 2 years of onset. Factors significantly associated with coronary events were large aneurysms, three or more aneurysms, and beaded aneurysms.

A systematic review of adherence to anticoagulation regimens in pediatric patients

Thromboembolic disease rates are increasing in pediatric patients. Anticoagulation is prescribed for treatment and prevention of thromboembolic disease. While nonadherence to anticoagulation regimens predicts poor health outcomes in adults, data in anticoagulated pediatric patients are limited. We systematically reviewed the rates, outcomes, and predictors of anticoagulation nonadherence in the pediatric population. Out of a total of 3581 unique articles identified for review, 17 studies met inclusion criteria. These studies primarily evaluated patients with cardiac disease treated with vitamin K antagonists. Overall nonadherence rates varied from 3% to 42%, based upon population, definition of adherence, and measurement strategy. Patient age, goal international normalized ratio (INR), and number of concurrent potentially interacting medications correlated with nonadherence. Data examining the relationship between nonadherence and health outcomes were included in only two studies. Limitations of current literature, as well as critical knowledge gaps that require future study, are discussed.

Anticoagulation in Pediatric Patients

Special aspects of anticoagulation in children include the different epidemiology of thrombosis, developmental changes in the coagulation system, age-dependent pharmacokinetics of anticoagulants, risk of bleeding, and practical hurdles to anticoagulation. The classical anticoagulants so far used in children have several limitations, resulting in the need for regular monitoring. The pharmacological properties of direct oral anticoagulants (DOACs) and the special challenges of anticoagulation in children make the DOACs particularly attractive for children. All DOACs have pediatric development programs, targeting various indications for prevention and treatment of thrombosis. Child-appropriate formulations have been developed, age-specific dosing information generated, and safety and efficacy evaluated in ongoing phase 3 trials. Rivaroxaban and dabigatran have already been authorized for children for treatment of acute venous thrombosis and for extended secondary prevention. Their safety and efficacy have been demonstrated comparable to that of standard-of-care anticoagulants, without need for monitoring. Further studies are ongoing, which are expected to lead to pediatric authorizations of DOACs for primary venous thromboembolic event prevention in some high-risk settings. More real-life data will be necessary from postmarketing studies and registries to complement the evidence base for DOAC use in children, particularly in the youngest age groups and special disease populations.

Abnormal Bedside Ultrasound Findings in a Complex Patient With Kawasaki Disease

We herein report a case of an 18-year-old female with Kawasaki disease who presented to the emergency department with epigastric abdominal pain and was subsequently found to have free fluid present in her abdomen visualized on bedside Focused Assessment with Sonography for Trauma (FAST) exam. Kawasaki disease is an acute vasculitis syndrome that primarily affects children and can have serious complications such as coronary artery aneurysms. The use of ultrasound in emergency departments is rapidly increasing, with the FAST being one of the most commonly performed bedside ultrasound examinations. FAST exams are most commonly performed in trauma patients as well as being part of the Advanced Trauma Life Support (ATLS) protocol. However, this case demonstrated that the FAST exam can also have application in other clinical scenarios and patient presentations where there is clinical suspicion of free intra-abdominal fluid.

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.

Low-Molecular-Weight Heparin vs Warfarin for Thromboprophylaxis in Children With Coronary Artery Aneurysms After Kawasaki Disease: A Pragmatic Registry Trial

BACKGROUND

The substantial risk of thrombosis in large coronary artery aneurysms (CAAs) (maximum z-score ≥ 10) after Kawasaki disease (KD) mandates effective thromboprophylaxis. We sought to determine the effectiveness of anticoagulation (low-molecular-weight heparin [LMWH] or warfarin) for thromboprophylaxis in large CAAs.

METHODS

Data from 383 patients enrolled in the International KD Registry (IKDR) were used. Time-to-event analysis was used to account for differences in treatment duration and follow-up.

RESULTS

From diagnosis onward (96% received acetylsalicylic acid concomitantly), 114 patients received LMWH (median duration 6.2 months, interquartile range [IQR] 2.5-12.7), 80 warfarin (median duration 2.2 years, IQR 0.9-7.1), and 189 no anticoagulation. Cumulative incidence of coronary artery thrombosis with LMWH was 5.7 ± 3.0%, with warfarin 6.7 ± 3.7%, and with no anticoagulation 20.6 ± 3.0% (P < 0.001) at 2.5 years after the start of thromboprophylaxis (LMWH vs warfarin HR 1.5, 95% confidence interval [CI] 0.4-5.1; P = 0.56). A total of 51/63 patients with coronary artery thrombosis received secondary thromboprophylaxis (ie, thromboprophylaxis after a previous thrombus): 27 LMWH, 24 warfarin. There were no differences in incidence of further coronary artery thrombosis between strategies (HR 2.9, 95% CI 0.6-13.5; P = 0.19). Severe bleeding complications were generally rare (1.6 events per 100 patient-years) and were noted equally for patients on LMWH and warfarin (HR 2.3, 95% CI 0.6-8.9; P = 0.25).

CONCLUSIONS

LMWH and warfarin appear to have equivalent effectiveness for preventing thrombosis in large CAAs after KD, although event rates for secondary thromboprophylaxis and safety outcomes were low. Based on our findings, all patients with CAA z-score ≥ 10 should receive anticoagulation, but the choice of agent might be informed by secondary risk factors and patient preferences.

Anti-thrombosis management of patients with Kawasaki disease: Results from an international survey

BACKGROUND

Patients with coronary artery aneurysms (CAA) after Kawasaki disease (KD) are at risk of thrombosis, which can lead to myocardial infarction or sudden death. Clinical practice guidelines recommend anticoagulation for high-risk patients.

METHODS

Web-based worldwide survey of physicians completed between 2016 and 2017 investigating anti-thrombotic management after KD. We compared management of patients by geographic location, Human Development Index (HDI) tier, and medical specialty.

RESULTS

The survey was completed by 603 physicians from 63 countries. In patients with normal coronaries, 95 (25%) of physicians recommended low-dose aspirin during long-term follow-up (>3 months after diagnosis). In patients with non-giant CAA, dual antiplatelet (e.g. aspirin and clopidogrel) was used by 121 (32%) of physicians, and anticoagulation by 72 (19%) of physicians. In patients with giant CAA, dual antiplatelet was used by 39 (10%) of physicians and anticoagulation by 285 (74%). In multivariable analysis, cardiology (OR 6.4 [95% CI 2.7, 16.1]) and rheumatology (OR 4.3 [95% CI 1.6, 12.6]) specialty (versus general pediatrics) were the only independent predictors of anticoagulant use in patients with giant CAA.

CONCLUSION

There is significant variation in anti-thrombosis management of patients with CAA after KD, with 26% of physicians not recommending anticoagulation of patients with giant CAA. Further studies are needed to evaluate the drivers of this practice variation to inform educational initiatives and to ascertain impact on long-term outcomes.

Coronary artery aneurysms are more severe in infants than in older children with Kawasaki disease

OBJECTIVE

We aimed to compare the severity of coronary artery abnormalities in Kawasaki disease between infants and older children.

METHODS

We retrospectively reviewed and compared coronary artery dilation and aneurysm severity in infants <1 year of age with Kawasaki disease at our centre over a 10-year period with that observed in children ≥1 year of age in the Pediatric Heart Network Trial of Pulse Steroid Therapy in Kawasaki Disease. Coronary artery abnormalities were defined by z-scores according to American Heart Association guidelines.

RESULTS

Of the 93 infants identified during the study period, 80 were treated with intravenous gamma globulin within the first 10 days of illness and were included for comparison to 170 children ≥1 year of age treated in the same time frame from the Pediatric Heart Network public database. The mean maximum z-score was significantly higher in infants compared with older children (3.37 vs 2.07, p<0.001). A higher incidence of medium and giant aneurysms was observed in infants compared with children ≥1 year of age (11% vs 3% for medium aneurysms, p=0.015; 8% vs <1% for giant aneurysms, p=0.005).

CONCLUSIONS

Infants with Kawasaki disease have more severe coronary artery dilation compared with older children, and a higher prevalence of medium and giant aneurysms. Because adverse outcomes are closely linked to the maximal coronary artery diameter in Kawasaki disease, patients diagnosed as infants require very close long-term monitoring for cardiac complications.

New insights into cardiovascular disease in patients with Kawasaki disease

PURPOSE OF REVIEW

Kawasaki disease presents many challenges to the diverse group of physicians who care for these patients including infectious disease specialists, rheumatologists, and cardiologists. Here we review some of the progress being made toward improved understanding of disease pathogenesis, treatment, and long-term outcomes.

RECENT FINDINGS

Epidemiologic studies in different populations documented increasing numbers of cases in countries with high physician awareness of the disease. These data suggest true increases in patient numbers rather than increases because of increased case ascertainment. Adequately powered clinical trials for adjunctive therapies continue to be an unmet need. Long-term consequences of damage to the arterial wall and myocardium are beginning to emerge and systematic, longitudinal observational studies are needed to better define outcomes.

SUMMARY

The unknown cause, lack of a specific diagnostic test, and uncertain future for patients who develop permanent cardiovascular damage all require further study.

Anticoagulant prophylaxis and therapy in children: current challenges and emerging issues

This review is aimed at describing the unique challenges of anticoagulant prophylaxis and treatment in children, and highlighting areas for research for improving clinical outcomes of children with thromboembolic disease. The evidence presented demonstrates the challenges of advancing the evidence base informing optimal management of thromboembolic disease in children. Recent observational studies have identified risk factors for venous thromboembolism in children, but there are few interventional studies assessing the benefit-risk balance of using thromboprophylaxis in risk-stratified clinical subgroups. A risk level-based framework is proposed for administering mechanical and pharmacological thromboprophylaxis. More research is required to refine the assignment of risk levels. The anticoagulants currently used predominantly in children are unfractionated heparin, low molecular weight heparin, and vitamin K antagonists. There is a paucity of robust evidence on the age-specific pharmacology of these agents, and their efficacy and safety for prevention and treatment of thrombosis in children. The available literature is heterogeneous, reflecting age-specific differences, and the various clinical settings for anticoagulation in children. Monitoring assays and target ranges are not well established. Nevertheless, weight-based dosing appears to achieve acceptable outcomes in most indications. Given the limitations of the classical anticoagulants for children, there is great interest in the direct oral anticoagulants (DOACs), whose properties appear to be particularly suitable for children. All DOACs currently approved for adults have Pediatric Investigation Plans ongoing or planned. These are generating age-specific formulations and systematic dosing information. The ongoing pediatric studies still have to establish whether DOACs have a positive benefit-risk balance in the various pediatric indications and age groups.