Successful treatment of infective endocarditis with recombinant tissue plasminogen activator

Fibrinolytic treatment using recombinant tissue-type plasminogen activator (rt-PA) for staphylococcal infective endocarditis

Infective endocarditis (IE) is a severe illness characterized by vegetation of bacterial thrombosis. We hypothesized that adding recombinant tissue-type plasminogen activator (rt-PA) to antibiotics would contribute to good results in the treatment of IE. As an in vitro study, we injected labeled Staphylococcus aureus (S. aureus) and either rt-PA or PBS + plasminogen into a polydimethylsiloxane flow chamber with fibrin on a coverslip, and then performed immunofluorescent area assessment. As an in vivo experiment, IE model rats that had suffered mechanical damage in the aortic valve by catheter and revealed bacterial vegetation caused by S. aureus injection were treated with either a control, cefazolin (CEZ), rt-PA, or rt-PA + CEZ, for 7 days. Survival was assessed for 14 days after the appearance of vegetation, with daily monitoring of the vegetation by transthoracic echocardiography (TTE). The in vitro investigation showed that perfusion of rt-PA could detach S. aureus significantly more efficiently than PBS could. In the in vivo research, the rt-PA + CEZ group survived significantly longer than the other groups, and rt-PA + CEZ was more effective than CEZ in the dissolution of vegetation, as observed by TTE. In conclusion, adding rt-PA to antibiotic treatment could dissolve the vegetation component synergistically and improve the survival rate.

An in vitro proof-of-principle study of sonobactericide

Infective endocarditis (IE) is associated with high morbidity and mortality rates. The predominant bacteria causing IE is Staphylococcus aureus (S. aureus), which can bind to existing thrombi on heart valves and generate vegetations (biofilms). In this in vitro flow study, we evaluated sonobactericide as a novel strategy to treat IE, using ultrasound and an ultrasound contrast agent with or without other therapeutics. We developed a model of IE biofilm using human whole-blood clots infected with patient-derived S. aureus (infected clots). Histology and live-cell imaging revealed a biofilm layer of fibrin-embedded living Staphylococci around a dense erythrocyte core. Infected clots were treated under flow for 30 minutes and degradation was assessed by time-lapse microscopy imaging. Treatments consisted of either continuous plasma flow alone or with different combinations of therapeutics: oxacillin (antibiotic), recombinant tissue plasminogen activator (rt-PA; thrombolytic), intermittent continuous-wave low-frequency ultrasound (120-kHz, 0.44 MPa peak-to-peak pressure), and an ultrasound contrast agent (Definity). Infected clots exposed to the combination of oxacillin, rt-PA, ultrasound, and Definity achieved 99.3 ± 1.7% loss, which was greater than the other treatment arms. Effluent size measurements suggested low likelihood of emboli formation. These results support the continued investigation of sonobactericide as a therapeutic strategy for IE.

Intracardiac Thrombosis Involving All Four Cardiac Chambers after Extracardiac Membranous Oxygenation Associated with MTHFR Mutations

A 4-month-old boy diagnosed with acute myocarditis was treated with extracorporeal membrane oxygenation (ECMO). Follow-up echocardiography eight hours after ECMO revealed intracardiac thrombosis involving all four heart chambers. Because of the high risk of systemic embolization due to a pedunculated thrombus of the aortic valve, we performed an emergency thrombectomy. After the operation, the patient had a minor neurologic sequela of left upper arm hypertonia, which had almost disappeared at the last outpatient clinic two months later. He was diagnosed with a major mutation in MTHFR (methylenetetrahydrofolate reductase), which is related to thrombosis.

Pediatric Cardiac Intensive Care Society 2014 Consensus Statement: Pharmacotherapies in Cardiac Critical Care Anticoagulation and Thrombolysis

OBJECTIVE

Thrombotic complications are increasingly being recognized as a significant cause of morbidity and mortality in pediatric and congenital heart disease. The objective of this article is to review the medications currently available to prevent and treat such complications.

DATA SOURCES

Online searches were conducted using PubMed.

STUDY SELECTION

Studies were selected for inclusion based on their scientific merit and applicability to the pediatric cardiac population.

DATA EXTRACTION

Pertinent information from each selected study or scientific review was extracted for inclusion.

DATA SYNTHESIS

Four classes of medications were identified as potentially beneficial in this patient group: anticoagulants, antiplatelet agents, thrombolytic agents, and novel oral anticoagulants. Data on each class of medication were synthesized into the follow sections: mechanism of action, pharmacokinetics, dosing, monitoring, reversal, considerations for use, and evidence to support.

CONCLUSIONS

Anticoagulants, antiplatelet agents, and thrombolytic agents are routinely used successfully in the pediatric patient with heart disease for the prevention and treatment of a wide range of thrombotic complications. Although the novel oral anticoagulants have been approved for a limited number of indications in adults, studies on the safety and efficacy of these agents in children are pending.

Recombinant tissue plasminogen activator as a novel treatment option for infective endocarditis: a retrospective clinical study in 32 children

Infective endocarditis is a life-threatening infectious syndrome, with high morbidity and mortality. Current treatments for infective endocarditis include intravenous antibiotics, surgery, and involve a lengthy hospital stay. We hypothesised that adjunctive recombinant tissue plasminogen activator treatment for infective endocarditis may facilitate faster resolution of vegetations and clearance of positive blood cultures, and therefore decrease morbidity and mortality. This retrospective study included follow-up of patients, from 1997 through 2014, including clinical presentation, causative organism, length of treatment, morbidity, and mortality. We identified 32 patients, all of whom were diagnosed with endocarditis and were treated by recombinant tissue plasminogen activator. Among all, 27 patients (93%) had positive blood cultures, with the most frequent organisms being Staphylococcus epidermis (nine patients), Staphylococcus aureus (six patients), and Candida (nine patients). Upon treatment, in 31 patients (97%), resolution of vegetations and clearance of blood cultures occurred within hours to few days. Out of 32 patients, one patient (3%) died and three patients (9%) suffered embolic or haemorrhagic events, possibly related to the recombinant tissue plasminogen activator. None of the patients required surgical intervention to assist vegetation resolution. In conclusion, it appears that recombinant tissue plasminogen activator may become an adjunctive treatment for infective endocarditis and may decrease morbidity as compared with current guidelines. Prospective multi-centre studies are required to validate our findings.

Treatment of neonatal fungal infective endocarditis with recombinant tissue plasminogen: activator in a low birth weight infant case report and review of the literature

With advances in medical sciences, an increase in survival rates of low birth weight; increased incidence in use of catheter and antibiotics, and total parenteral nutrition are reported, therefore, the rate of fungal infections in late and very late onset neonatal sepsis have increased. Although fungal endocarditis rarely occur in newborns, it has a high morbidity and mortality. Antifungal therapy is often insufficient in cases who develop fungal endocarditis and surgical treatment is not preferred due to its difficulty and high mortality. Herein, fungal endocarditis in a preterm newborn treated with single-dose recombinant tissue plasminogen activator in addition to antifungal therapy is presented and relevant literature has been reviewed. The vegetation completely disappeared following treatment and no complication was observed.

Antithrombotic therapy in neonates and children: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

Neonates and children differ from adults in physiology, pharmacologic responses to drugs, epidemiology, and long-term consequences of thrombosis. This guideline addresses optimal strategies for the management of thrombosis in neonates and children.

METHODS

The methods of this guideline follow those described in the Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.

RESULTS

We suggest that where possible, pediatric hematologists with experience in thromboembolism manage pediatric patients with thromboembolism (Grade 2C). When this is not possible, we suggest a combination of a neonatologist/pediatrician and adult hematologist supported by consultation with an experienced pediatric hematologist (Grade 2C). We suggest that therapeutic unfractionated heparin in children is titrated to achieve a target anti-Xa range of 0.35 to 0.7 units/mL or an activated partial thromboplastin time range that correlates to this anti-Xa range or to a protamine titration range of 0.2 to 0.4 units/mL (Grade 2C). For neonates and children receiving either daily or bid therapeutic low-molecular-weight heparin, we suggest that the drug be monitored to a target range of 0.5 to 1.0 units/mL in a sample taken 4 to 6 h after subcutaneous injection or, alternatively, 0.5 to 0.8 units/mL in a sample taken 2 to 6 h after subcutaneous injection (Grade 2C).

CONCLUSIONS

The evidence supporting most recommendations for antithrombotic therapy in neonates and children remains weak. Studies addressing appropriate drug target ranges and monitoring requirements are urgently required in addition to site- and clinical situation-specific thrombosis management strategies.

The use of recombinant tissue-type plasminogen activator in a newborn with an intracardiac thrombus developed during extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) support is often used to support infants and children with hemodynamic or respiratory failure. One of the major obstacles of safely treating a child with ECMO is balancing the risk of hemorrhage with the potential for thrombus development. Managing thrombosis in the setting of ECMO is challenging and has no defined algorithm. The use of recombinant tissue-type plasminogen activator (tPA) for thrombolysis has been previously described in cases where thrombi have developed despite adequate anticoagulation. In such situations, the risk of hemorrhage must be carefully balanced with the benefit of dissolving the clot and reestablishing flow. We present a case of an infant who required ECMO because of severe primary pulmonary hypertension and subsequently developed a right atrial thrombus adjacent to the ECMO cannula. The patient was treated with tPA with immediate improvement but had fatal intracranial hemorrhage almost 3 days after the tPA was administered. In this report, we review the current literature on tPA use during ECMO support and suggest a rational approach.

The use of recombinant tissue plasminogen activator in the management of infective intracardiac thrombi in pre-term infants with thrombocytopaenia

Bacterial endocarditis complicated by the development of intra-cardiac thrombus presents a difficult management dilemma in the pre-term infant. Here we present our experience with three infants who had this condition, all of whom were successfully managed using therapy with recombinant tissue plasminogen activator (r-TPA). Therapy in one of the infants was particularly instructive, as the condition was further complicated by severe thrombocytopaenia, making the decision to treat using r-TPA difficult.

Intracranial hemorrhage following thrombolytic use for stroke caused by infective endocarditis

BACKGROUND AND PURPOSE

Stroke is one of the most common neurological manifestations of infective endocarditis. The use of intravenous tissue plasminogen activator (t-PA) in the management of acute ischemic stroke is the accepted standard of practice. Current guidelines for intravenous (IV) t-PA therapy in acute ischemic stroke do not exclude patients with infective endocarditis. We present three patients who received IV t-PA for acute ischemic stroke in the setting of infective endocarditis and developed multifocal intracranial hemorrhage as a complication.

CONCLUSION

Infective endocarditis related strokes are associated with a higher risk of hemorrhagic complications and our experience suggests that IV t-PA use may potentiate that risk.

Bacterial endocarditis in a child presenting with acute arterial ischemic stroke: should thrombolytic therapy be absolutely contraindicated?

Thrombolysis is considered to be contraindicated in acute ischemic stroke secondary to infective endocarditis (IE). We report a 12-year-old female who presented with acute dense right hemiparesis and aphasia. Cranial magnetic resonance imaging and angiography showed multiple diffusion-restricted lesions in the left hemisphere and absence of flow in the left internal carotid artery. She was treated with intra-arterial tissue plasminogen activator within 6 hours of her presentation. Subsequently she was diagnosed with pneumococcal endocarditis and underwent debridement of vegetations and patch repair of the mitral valve. The patient did not have hemorrhagic complications following thrombolytic therapy or surgery. Pathological analysis of the mitral valve vegetations revealed mostly fibrin thrombus. Follow-up imaging showed complete recanalization of the left internal carotid artery, and the patient had a remarkable neurological recovery. This is the first case report of successful intra-arterial thrombolytic therapy in childhood IE-related stroke. We believe that thrombolytic therapy contributed to a favorable outcome in our patient and may be safe in selected patients with childhood IE-related acute ischemic stroke.

Antithrombotic therapy in neonates and children: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

This chapter about antithrombotic therapy in neonates and children is part of the Antithrombotic and Thrombolytic Therapy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs, and Grade 2 suggests that individual patient values may lead to different choices (for a full understanding of the grading, see Guyatt et al in this supplement, pages 123S-131S). In this chapter, many recommendations are based on extrapolation of adult data, and the reader is referred to the appropriate chapters relating to guidelines for adult populations. Within this chapter, the majority of recommendations are separate for neonates and children, reflecting the significant differences in epidemiology of thrombosis and safety and efficacy of therapy in these two populations. Among the key recommendations in this chapter are the following: In children with first episode of venous thromboembolism (VTE), we recommend anticoagulant therapy with either unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) [Grade 1B]. Dosing of IV UFH should prolong the activated partial thromboplastin time (aPTT) to a range that corresponds to an anti-factor Xa assay (anti-FXa) level of 0.35 to 0.7 U/mL, whereas LMWH should achieve an anti-FXa level of 0.5 to 1.0 U/mL 4 h after an injection for twice-daily dosing. In neonates with first VTE, we suggest either anticoagulation or supportive care with radiologic monitoring and subsequent anticoagulation if extension of the thrombosis occurs during supportive care (Grade 2C). We recommend against the use of routine systemic thromboprophylaxis for children with central venous lines (Grade 1B). For children with cerebral sinovenous thrombosis (CSVT) without significant intracranial hemorrhage (ICH), we recommend anticoagulation initially with UFH, or LMWH and subsequently with LMWH or vitamin K antagonists (VKAs) for a minimum of 3 months (Grade 1B). For children with non-sickle-cell disease-related acute arterial ischemic stroke (AIS), we recommend UFH or LMWH or aspirin (1 to 5 mg/kg/d) as initial therapy until dissection and embolic causes have been excluded (Grade 1B). For neonates with a first AIS, in the absence of a documented ongoing cardioembolic source, we recommend against anticoagulation or aspirin therapy (Grade 1B).

Outcome of cardiac thrombi in infants

Use of central lines in the neonatal intensive care unit (NICU) has led to the formation of intracardiac thrombi. A paucity of data exists on the management of neonatal cardiac thrombi, with the few reported cases focusing on outcomes following thrombolytic therapy. This study was undertaken to evaluate the outcome of cardiac thrombi in neonates who do not receive thrombolytic therapy. Nineteen patients younger than 3 months of age diagnosed with cardiac thrombi were included. All 19 patients had a central line. Management consisted of a combination of antibiotics and low-molecular-weight heparin (n = 16) or surgical removal (n = 2). In one case, no treatment was instituted. One patient was lost to follow-up after partial resolution of the thrombus. Complete thrombus resolution occurred in 18 patients, 9 with negative blood cultures and 9 with positive blood cultures. It took longer for resolution of thrombi associated with positive blood cultures than for sterile thrombi. No patient had evidence of thrombus embolization. From these data we concluded that the natural history of cardiac thrombi is resolution. Infected thrombi require more prolonged therapy. Surgery is seldom required and thrombolytics are not usually necessary for clot resolution.

Treatment of infective endocarditis with recombinant tissue plasminogen activator

Infective endocarditis (IE) caused by microbial infection is virtually always fatal if untreated. High-dose and long-term antibiotic treatment is required to eradicate microorganisms. If increased risk of embolic events, persistent infection, and progressive cardiac failure are present, surgery is indicated. However, surgery can carry an increased risk of mortality and morbidity in critically ill children of whom other treatment options such as administering, a thrombolytic agent; recombinant tissue plasminogen activator (r-tPA) could be an alternative choice. Here, we report a 14-year-old male with Down syndrome and acute myeloblastic leukemia, diagnosed with IE characterized by two large vegetations on aortic and mitral valves, who was successfully treated with r-tPA.

Tricuspid Valve Repair in an Infant With Multiple Obstructive Candida Mycetomas

Neonatal fungal valve endocarditis is an uncommon and highly lethal disease. The ideal management strategy is still controversial. Current options include antifungal chemotherapy and surgical intervention, the latter being often limited by risks inherent with valve operations in low body weight infants. We present a case of a premature infant with multiple Candida tricuspid valve mycetomas. Eradication of infection was achieved by combined liposomal amphotericin therapy and complex tricuspid valve repair. Indications, technical aspects, and outcome of treatment in infants are reviewed.