Search Results (2)

Background: Minimally invasive heart valve surgery via anterolateral mini-thoracotomy with full endoscopic 3D visualization (MIS) has become the standard treatment of patients with valvular heart disease and low operative risk over the past two decades. It requires extracorporeal circulation and cardioplegic arrest. The most established form of arterial cannulation for MIS is through the femoral artery and is used by most surgeons, but it is suspected to increase the risk of stroke through retrograde blood flow. An alternative route of cannulation is the axillary artery, producing antegrade blood flow during extracorporeal circulation. Methods: Femoral or axillary cannulation for extracorporeal circulation during minimally invasive heart valve surgery (FAMI) is a multicenter randomized controlled trial designed to determine whether axillary cannulation is superior to femoral cannulation for the outcome of a manifest stroke within 7 days postoperatively. The target sample size was 848 participants. Patients ≥ 18 years of age, with valvular regurgitation or stenosis scheduled for minimally invasive surgery via anterolateral mini-thoracotomy, were randomized to axillary cannulation (treatment group) or to femoral cannulation (standard care). Patients were followed up for seven days postoperatively. A CT scan was performed pre-operatively to screen patients for vascular calcifications and to assess the safety of femoral cannulation. The standard of care is femoral artery cannulation, but is performed only in patients without significant vascular calcifications or severe kinking of the iliac arteries and in patients with sufficient vessel diameter. The cannulation is performed via Seldinger’s technique, and the vessel closed percutaneously using a plug-based vascular closure device. Only patients without significant vascular calcifications are considered for femoral cannulation, as an increased risk of stroke is assumed. In patients with vascular calcifications, axillary cannulation is the standard of care to avoid these risks. Retrospective studies have hinted that, even in patients without vascular calcifications, there may be a lower stroke risk with axillary cannulation compared to femoral cannulation. We present a protocol for a multi-center randomized trial to investigate this hypothesis. Discussion: To date, evidence on the best access for peripheral artery cannulation during minimally invasive heart valve surgery has been scarce. Patients may benefit from axillary cannulation for extracorporeal circulation in terms of stroke risk and other neurological and vascular complications, though femoral cannulation is the gold standard. The aim of this study is to determine the risks of peri-operative stroke in a prospective randomized comparison of femoral vs. axillary cannulation. Full article

Valveless pumping phenomena (peristalsis, Liebau-effect) can generate unidirectional fluid flow in periodically compressed tubular conduits. Early embryonic hearts are tubular conduits acting as valveless pumps. It is unclear whether such hearts work as peristaltic or Liebau-effect pumps. During the initial phase of its pumping activity, the originally straight embryonic heart is subjected to deforming forces that produce bending, twisting, kinking, and coiling. This deformation process is called cardiac looping. Its function is traditionally seen as generating a configuration needed for establishment of correct alignments of pulmonary and systemic flow pathways in the mature heart of lung-breathing vertebrates. This idea conflicts with the fact that cardiac looping occurs in all vertebrates, including gill-breathing fishes. We speculate that looping morphogenesis may improve the efficiency of valveless pumping. To test the physical plausibility of this hypothesis, we analyzed the pumping performance of a Liebau-effect pump in straight and looped (kinked) configurations. Compared to the straight configuration, the looped configuration significantly improved the pumping performance of our pump. This shows that looping can improve the efficiency of valveless pumping driven by the Liebau-effect. Further studies are needed to clarify whether this finding may have implications for understanding of the form-function relationship of embryonic hearts. Full article