Search

Pump thrombosis is a major complication of CF LVAD therapy, affecting approximately 5% of HVAD (HeartWare) patients. We report a 76-year-old male with stage D congestive heart failure and three years of HVAD destination therapy experiencing a low-flow alert. Echocardiography revealed insufficient LV unloading. A lowered average flow of 1.98 L/min was observed, and power consumption remained at 3.1 Watts at 2700 rpm. No changes in the acoustic signal and an absence of hemolysis evidence in the serum workup. CT angiography showed LV dilatation with no outflow cannula thrombosis or stenosis and was negative for pulmonary embolism.Therefore, a pre-pump thrombus was suspected. For destination therapy, patients' pump exchange is the gold standard for managing LVAD thrombosis. As the HVAD was not available at this moment, pump exchange with the HeartMate 3 (HM3) appeared not practicable in this sick patient. Hence, a retrograde thrombus washout maneuver was performed while the patient was awake and spontaneously breathing: With vasopressors, mean blood pressure was raised to 100 mmHg, and ventricular contractility was improved with intravenous adrenaline. The pump was turned off for 10 seconds while manually squeezing carotid arteries in Trendelenburg's position to avoid cerebral thromboembolism. After restarting the pump, the parameters reverted to normal, with a flow of 4.2 L/min and a power of 4.1 Watts at 2700 rpm.The patient had no perfusion or neurological abnormalities during or after the procedure. Pre-pump, intra-pump, and post-pump flow obstructions can occur as HVAD flow obstructions (Figure 1). Pump exchange remains the gold standard for managing LVAD thrombosis, but the invasiveness of the surgery disqualifies some patients: In particular, the exchange of an HVAD pump in the current era involves not only medical and surgical obstacles but also a logistical dilemma, as Medtronic terminated the distribution and sale of the HVAD system on June 3, 2021. [ABSTRACT FROM AUTHOR]

Abstract: After an accidental radioactive contamination by aerosols in inhabited areas, the radiation exposure to man is determined by complex interactions between different factors such as dry or wet deposition, different types of ground surfaces, chemical properties of the radionuclides involved and building development as well as dependence on bomb construction e.g. design and geometry. At short-term, the first rainfall is an important way of natural decontamination: deposited radionuclides are washed off from surfaces and in urban areas the resulting contaminated runoff enters the sewer system and is collected in a sewage plant. Up to now the potential exposure caused by this process has received little attention and is estimated here with simulation models. The commercial rainfall-runoff model for urban sewer systems KANAL++ has been extended to include transport of radionuclides from surfaces through the drainage to various discharge facilities. The flow from surfaces is modeled by unit hydrographs, which produce boundary conditions for a system of 1d coupled flow and transport equations in a tube system. Initial conditions are provided by a map of surface contamination which is produced by geo-statistical interpolation of γ-dose rate measurements taking into account the detector environment. The corresponding methodology is implemented in the Inhabited Area Monitoring Module (IAMM) software module as part of the European decision system JRODOS. A hypothetical scenario is considered where a Radiation Dispersal Device (RDD) with Cs-137 is detonated in a small inhabited area whose drainage system is realistically modeled. The transition of deposited radionuclides due to rainfall into the surface runoff is accounted for by different nuclide-specific entrainment coefficients for paved and unpaved surfaces. The concentration of Cs-137 in water is calculated at the nodes of the drainage system and at the sewage treatment plant. The external exposure to staff of the treatment plant is estimated. For Cs-137 radiation levels in the plant are low since wash-off of cesium from surfaces is an ineffective process. [Copyright &y& Elsevier]

Purpose Cardiac recovery after mechanical circulatory support allows explantation of the left ventricular assist device (LVAD). So far, no FDA approved or CE certified plug is available for the explantation of newest generation HeartMate 3TM. Here, we present an individualized explantation strategy with an in-house developed patient-tailored silicone plug for the HeartMate 3™ LVAD avoiding (re-) sternotomy. Methods Hemodynamic evaluation of two HeartMate 3TM patients was performed in order to assess cardiac recovery and hereby planning a LVAD explantation strategy avoiding (re-) sternotomy. A preoperative CT scan was used to define the ideal dimensions of the silicone plug fitting with a HeartMate 3TM mock apical ring. The cylindrical plug was made out of medical grade liquid silicone elastomer MED-4820 (NuSil Silicone Technology LLC, Carpinteria, USA) using a patient specific high quality surface casting mold and subsequently sterilized in a clinical standard process. Its geometry was defined by the inner diameter of the apical cuff and the patient's CT data implementing one rounded end and a cylindrical head with cross-shaped suture guides on the other end. Results Following CT scans of two HeartMate 3TM patients, individualized explantation of the LVAD was planned with a patient-tailored silicone plug. Both patients could be successfully weaned from VAD support and explanted with a lateral thoracotomy. No apical bleeding occurred after VAD removal and silicone plug insertion. The plugs could be inserted easily and reliably secured with crossing sutures. The patients were monitored on ICU and could be discharged home in the following days. Conclusion The surgical removal of HeartMate 3TM is feasible using a patient-tailored silicone plug avoiding (re-) sternotomy. The medical grade liquid silicone elastomer allows perfect patient-specific fitting with pre-operative CT-measured dimensions. [ABSTRACT FROM AUTHOR]