We identified 3 types of LVAD-related blood flow obstruction, and developed an algorithm for optimal diagnosis and treatment.

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This paper reviews the development and establishment of the Berlin Heart EXCOR® (BHE®) as a paediatric mechanical circulatory support and reports our entire experience with regard to indications, timing of implantation and explantation and outcome. The Berlin group reported the first successful paediatric bridge to transplantation using a pulsatile pneumatic paracorporeal biventricular assist device, the BHE®, in 1990 in an 8-year-old boy with end-stage heart failure and coarctation of the aorta. This experience prompted them to develop miniaturized pump systems for children through the company Berlin Heart Mediproduct GmbH. The development and production of BHE® to support paediatric patients with heart failure then began. Between 1990 and 2013, the BHE® has been implanted in 122 patients (median age 8.64 years, range 3 days to 17 years) with heart failure, who were inotrope-dependent or switched from extracorporeal membrane oxygenation support or had postcardiotomy low-output syndrome. Thirty-five patients were <1 year old (median 125 days). The aetiology of heart failure included cardiomyopathy in 56 (median age 9.14 years), fulminant myocarditis in 17 (median age 8.2 years), end-stage congenital heart disease in 18 (median age 6.4 years), postcardiotomy heart failure (after correction of congenital heart disease) in 28 (median age 9.6 years) and transplant graft failure in 3 (median age 12.5 years). The overall median duration of implantation was 63.6 (range 1-841) days. Fifty-six children eventually underwent orthotopic heart transplantation. Eighteen patients had myocardial recovery and were weaned successfully. They had entirely normal cardiac function after a range of 4-10 years after surgery. At the time of this report, five patients were still on support, with a duration of 354-369 days. Forty-three patients died on the system from loss of peripheral circulatory resistance, multiorgan damage, sepsis or haemorrhagic or thrombotic complications. Re-exploration because of bleeding was necessary in 22 patients. Pump exchange because of thrombus formation in the valves was necessary 35 times. With the introduction of a modified anticoagulation regimen in 2000, the pump exchange rate has decreased. The BHE® can reliably support the circulation at any age for long periods with good results. It is now an established treatment for children with heart failure of any aetiology.

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Implantation of rotary blood pumps is an established treatment for end-stage heart failure. Anticoagulation is routinely used for reducing pump thrombosis, but this severe complication still occurs in 5-8% of patients. In 105 patients, the sound produced by the left ventricular assist device HeartWare HVAD was prospectively and sequentially recorded. The acoustic spectra calculated by runtime fast Fourier transformation were investigated. Results were compared with respect to patients without thrombotic complications (97 patients) and those with signs of pump thrombosis (8 patients). All eight pumps exchanged were opened and investigated. Thrombus formation was confirmed in all eight exchanged pumps. The existence of a sound peak with the threefold frequency of the pump speed correlated with the presence of thrombi inside the pump (p < 0.001). An increase in the sound amplitude of the rotary frequency of approximately 75% compared to previous measurements also denotes pump thrombosis. Analysis of the acoustic spectrum of the HVAD pump can be used as a reliable method to detect pump thrombosis. The appearance of third harmonics indicates the presence of thrombotic particles independently of previous baseline measurements. The goal of this study is to define and validate such a method.