Surgical intervention

Hybrid AF ablation
Patients with severe atrial fibrillation can be offered either a percutaneous, catheter based ablation procedure or a surgical procedure. Despite many improvements, the success ratio of both these approaches has major limitations. Some ten years ago, the idea was raised that the shortcomings of either of these approaches could be abolished by combining the two of them in a single and simultaneous endo and epicardial ablation procedure. To this end, the invasive surgical procedure had to be scaled down first to a minimally invasive, thoracoscopic approach that would hardly add any additional trauma to the percutaneous endocardial approach. By dogged perseverance, testing many tools and ways of access to the left atrium, our cardiac surgeons eventually succeeded in developing a procedure that meets these requirements. As a result, in 2008 a clinical, so called hybrid AF ablation program was launched that is performed now on a routine base but uniquely at the Maastricht UMC+ by electrophysiologists and surgeons working together in one single team and which attracts numerous visitors from abroad.

Biomaterials for local drug delivery
Local delivery of drugs may increase therapeutic efficacy while reducing adverse effects. In this research project various drug delivering biomaterials are developed for cardiac applications. These biomaterials can be applied either intrapericardially, epicardially or intramyocardially. To study pharmacokinetics and pharmacodynamics, several formulations of microspheres, hydro gels and patches areemployed. Regarding clinical applicability, points of interest are controlled drug delivery, biocompatibility and biodegradation. During the first phase, the project focuses on prevention of post-operative atrial fibrillation via local delivery of antiarrhythmic drugs. In our program we also study antimicrobial coatings for central venous catheters. New materials are analyzed in vitro with accepted models. Currently we focus on coatings combining long-term antimicrobial action and good hemocompatibility through use of silver nanoparticles.Silver coatings which lower the risk for infection and thrombosis can contribute substantially to safer use of central venous catheters.

Extracorporeal Life Support
The aim of this research project is to develop an automated ELS system which assesses the hemodynamic interaction of the ELS system with the patient, and auto-adapts cardiopulmonary support. For this purpose, we validated a new monitoring parameter, the dynamic filling index (DFI). The index shows the correlation between pump speed, drainable volume, and resulting pump flow, and is given by the slope of the curve.

Preclinical and clinical studies have demonstrated the superiority of the DFI above commonly used parameters for hemodynamic monitoring. Parameters like pump inlet pressure, pump flow, and arterial line pressure were not able to reveal small but clinically important changes in drainable volume at the drainage site, whereas the DFI significantly detected a change in the flow-speed curve. Our DFI-based automated closed-loop pump control has proven to be effective in assessing circulatory filling, and can adapt pumping efficiency to maintain support flow during critical low-filling conditions. In addition to the monitoring and control of pumping efficiency and bypass flow, latest applications of the DFI are focussing on its clinical use to facilitate weaning after prolonged support.