Femoral or Axillary Cannulation for Extracorporeal Circulation during Minimally Invasive Heart Valve Surgery (FAMI): Protocol for a Multi-Center Prospective Randomized Trial

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.