Compromised peripheral tissue oxygenation during surgery may lead to worse patient outcome, mainly due to post-operative infections or heart failure. Insufficient stroke volume and/or cardiac output due to hypovolemia or cardiac defects play a central role in causing poor peripheral tissue oxygenation. In order to assess stroke volume, there are numerous invasive and non-invasive methods available. Up to the present date it is unknown, if these methods may by used interchangeably in patients with severe cardiac defects like aortic stenosis.

Inclusion Criteria:

• scheduled transcatheter aortic valve implantation
• signed patient consent form
• aged 18 or older by time of surgery
• no participation in other clinical trials

Exclusion Criteria:

• pregnant or breast-feeding women
• emergency surgery

Cardiac surgery at a university hospital