Surgical thrombectomy of two left ventricular thrombi in a child with acute myocarditis

Myocarditis is a potentially life-threatening disease. Although ventricular thrombus formation in myocarditis is rare, it carries the risk of serious complications. We report on a 10-year-old previously healthy girl presenting with 2 large left ventricular thrombi in acute lymphocytic acute myocarditis. No coagulation disorder was found. Her clinical course and mobile thrombi characteristics prompted us to carry out an urgent surgical thrombectomy rather than primary anticoagulation therapy. The patient has recovered well without clinical signs of thromboembolism.

Parameters of haematology, clinical chemistry and lipid metabolism in the common marmoset and alterations under stress conditions

Common marmosets are suitable non-human primate models for many human diseases. Standard values for blood parameters are required to evaluate physiological and pathological situations. Two studies were conducted: study I to determine standard values and study II to examine these under changed housing conditions. In study I, all parameters for clinical chemistry were similar in range for both genders with these specifics: male marmosets had significantly higher total and LDL cholesterol levels than females, whereas the mean corpuscular volume and the mean corpuscular haemoglobin were significantly lower than in females. In study II, glucose, lymphocytes and salivary cortisol were significantly lower, and faecal cortisol was increased during the change of housing conditions. In conclusion, standard values for haematology and clinical chemistry for the common marmoset were determined. Further on, parameters that are influenced by relocation stress and its importance for experimental results are described.

Coil-occlusion of the left ventricle as emergency treatment in failing stage I palliation for hypoplastic left heart syndrome with sinusoids

We report on a patient with hypoplastic left heart syndrome (HLHS), ventricular septal defects, and coronary sinusoids who suffered recurrent myocardial ischemic events that required cardiopulmonary resuscitation after stage I palliation. We identified the main reason to be a steal phenomenon of blood from the left coronary artery via the sinusoids into the rudimentary left ventricle and across the septal defects into the right ventricle. To limit this coronary steal phenomenon, we successfully performed transcatheter closure of the left ventricle with implantation of three Microplex Terumo-Coils. This led to the patient's clinical stabilization. Stage II surgery took place at the age of 5 months without difficulty. In the setting of a symptomatic neonate with HLHS and ventriculocoronary connections, embolization of the left ventricle is a feasible interventional therapy.

Prophylactic use of clopidogrel in paediatric cardiac patients

Thromboembolic complications in infants with congenital heart defects are common despite inhibition of platelet function with acetylsalicylic acid (ASS). Yet there is still insufficient pharmacologic data on the use of clopidogrel in infants. The adult dose of 75 mg/d is significantly higher than the dose lately recommended in infants (0.2 mg/kg/d). Moreover, we know of nonresponders to both acetylsalicylic acid and clopidogrel. Normal coagulation tests fail to identify those patients.Prospective monocentric study on 14 children (median age 5, range 0.7-84 months, 9 male, 5 female). Shunt thrombosis had occurred in 4 infants on ASS therapy. Seven days after starting clopidogrel (0.2 mg/kg/d), platelet function was tested by stimulation with ADP (4 and 10 µmol/l). We considered the range for the clopidogrel effect to be optimal if the maximum aggregation on ADP 4 µmol/l was between 30-50%.Clopidogrel 0.18-0.24 mg/kg/d in addition to ASS 2-4 mg/kg/d resulted in effective inhibition of platelet function in 93% (ADP 4 µmol/l: median 38%, range 30-63). All patients were responders. We observed neither any thromboembolic events nor severe bleeding episodes during the median 11-month follow-up period (range 1-30 mo).Testing platelet function makes clopidogrel dosing safer, and simplifies therapy adjustments in long-term treatment. A clopidogrel dose of 0.2 mg/kg/d was safe and effective in combination with ASS in this small patient cohort.

The conclusiveness of less-invasive imaging techniques (computer tomography, X-ray) with regard to their identification of bone diseases in a primate model (Callithrix jacchus)

BACKGROUND

Although common marmosets seem to be appropriate animal models to examine bone diseases, no data about the conclusiveness of less-invasive techniques are available. Therefore, the aim was to combine different techniques to analyse changes in bone metabolism of common marmosets with bone diseases.

METHODS

Five monkeys were examined by X-ray, computer tomography (CT), histology and immunohistochemistry (IHC).

RESULTS

Monkeys with lowest bone mineral density (BMD) showed increased bone marrow, decreased cancellous bone and decreased contrast in X-ray. Highest alkaline phosphatase (AP)-levels were detected in bones with low elastic modulus. Expression of osteopontin (OPN), osteocalcin (OC) and runt-related transcriptions factor 2 (RUNX 2) was detected in bones with high modulus. No expression was present in bones with lower modulus. Collagen type I and V were found in every bone.

CONCLUSIONS

In conclusion, CT, X-ray and AP are useful techniques to detect bone diseases in common marmosets. These observations could be confirmed by IHC.

4D-MR flow analysis in patients after repair for tetralogy of Fallot

OBJECTIVES

Comprehensive analysis of haemodynamics by 3D flow visualisation and retrospective flow quantification in patients after repair of tetralogy of Fallot (TOF).

METHODS

Time-resolved flow-sensitive 4D MRI (spatial resolution ~ 2.5 mm, temporal resolution = 38.4 ms) was acquired in ten patients after repair of TOF and in four healthy controls. Data analysis included the evaluation of haemodynamics in the aorta, the pulmonary trunk (TP) and left (lPA) and right (rPA) pulmonary arteries by 3D blood flow visualisation using particle traces, and quantitative measurements of flow velocity.

RESULTS

3D visualisation of whole heart haemodynamics provided a comprehensive overview on flow pattern changes in TOF patients, mainly alterations in flow velocity, retrograde flow and pathological vortices. There was consistently higher blood flow in the rPA of the patients (rPA/lPA flow ratio: 2.6 ± 2.5 vs. 1.1 ± 0.1 in controls). Systolic peak velocity in the TP was higher in patients (1.9 m/s ± 0.7 m/s) than controls (0.9 m/s ± 0.1 m/s).

CONCLUSIONS

4D flow-sensitive MRI permits the comprehensive evaluation of blood flow characteristics in patients after repair of TOF. Altered flow patterns for different surgical techniques in the small patient cohort may indicate its value for patient monitoring and potentially identifying optimal surgical strategies.

Trans-catheter closure of the native aortic valve with an Amplatzer Occluder to treat progressive aortic regurgitation after implantation of a left-ventricular assist device

We report on a patient with ischaemic dilated cardiomyopathy, who developed progressive regurgitation of his native aortic valve after implantation of a left-ventricular assist device (LVAD, HeartMate II). Increasing regurgitant volume led to reduced effective cardiac output and worsening of symptoms. To overcome aortic regurgitation, we successfully closed his aortic valve minimally invasively using the Amplatzer(®) P.I. Muscular VSD Occluder. This led to instant haemodynamic stabilisation. We observed significant residual regurgitation through the Occluder during the initial phase, which led temporarily to increased haemolysis and subsequently to worsening of kidney function; once the haemolysis ceased, we noted a very good interventional and clinical result at short-term follow-up.

Experimental Model for Heart Failure in Rats - Induction and Diagnosis

BACKGROUND

Clinical heart failure is generally preceded by hypertrophy. Many animal models (e. g. toxic heart failure models) do not consider this hypertrophy. We set out to develop a heart failure model in rats by inducing pressure-overload hypertrophy.

METHODS

We induced coarctation of the aortic arch with a tantalum clip (0.35 mm internal diameter) In 3-week-old rats (n=17). Starting at seven weeks postoperatively, we measured ejection fraction (EF), fractional shortening (FS), end-systolic (LVESD) and end-diastolic (LVEDD) left ventricular dimensions by echocardiography each week. Heart, lung, and liver specimens were analyzed histopathologically at least eleven weeks after the operation.

RESULTS

Contractile function was significantly decreased in hearts from animals with aortic banding (EF: 45+/-5% vs. 73+/-5%, p<0.01; FS: 20+/-3% vs. 35+/-5%, p<0.01). At the same time, left ventricles were dilated (LVEDD: 9.1+/-0.6 mm vs. 7.4+/-0.5 mm; LVESD: 7.3+/-0.6 mm vs. 4.8+/-0.4 mm, p<0.01). These observations were associated with clinical and histopathological changes characteristic for chronic left heart failure.

CONCLUSION

Placing a tantalum clip around the aortic arch in 3-week-old rats consistently induces left ventricular decrease in contractile function and dilatation after eleven weeks.

Arginine506 to glutamin mutation in the factor V gene in infancy and childhood: evidence of fibrinolytic impairment

Resistance to activated protein C (APCR), in the majority of cases due to arginine506 (Arg506) to glutamine (Gln) mutation in the factor V gene, has emerged as the most important hereditary cause of venous thrombo-embolism. To determine to what extent this relatively common gene mutation influences the fibrinolytic system we investigated a population of APC resistant children (n = 65) in comparison with a control group of sex- and age-matched healthy children (n = 100). Compared to the controls, plasma levels of tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA) and plasminogen activator inhibitor (PAI) 1 antigen, D-Dimer and enhanced thrombin generation were significantly (P < 0.0001) increased in children with the common factor V mutation. No difference was found between symptomatic and non-symptomatic children. Whether high concentrations of t-PA, u-PA and PAI 1 antigen can predict future vascular occlusion in children with APCR requires a more extensive multicentre study.

CONCLUSION

Our data indicate that hypercoagulability in children with the Arg506 to Gln mutation in the factor V gene is mainly attributed to the genetic aetiology of the disease.

[Abuse of artificial sweetener as differential diagnosis of lactose intolerance]

A two year old dystrophic boy with chronic diarrhea was described. At the age of 6 month the boy developed a severe gastroenteritis with a secundary lactase deficiency. Dietary treatment was however not successful and consequently the boy became dystrophic. At last, an abuse of sweetener was diagnosed.