SodiUm SeleniTe Adminstration IN Cardiac Surgery (SUSTAIN CSX®-Trial).

The aim of the investigators' research program is to investigate the effects of perioperative high dose selenium supplementation in high-risk cardiac surgical patients undergoing complicated open heart surgery. The investigators hypothesize that the therapeutic strategy tested in this randomized trial may contribute to a fewer complications, less organ injury and fewer deaths. Before the investigators conducted the large definitive trial, they conducted a pilot study to assess the feasibility of the protocol, and are rolling the pilot patients into the definitive trial.

Over a million patients undergo open heart surgery annually and this number is likely to accelerate as the population ages and the prevalence of diabetes and cardiovascular disease continue to increase. Unfortunately, death, organ failure, and other serious complications are all too frequent following open heart surgery, especially in some high-risk patient populations.

Selenium is a trace element that is important for many of the body's regulatory and metabolic functions especially during times of stress. International members of the study team have shown in a non-randomized study that high dose selenium supplementation was associated with improved clinical outcomes compared to a historical control group. The next step in this program of research is to conduct a randomized trial.

The aim of this research program is to investigate the effects of perioperative high dose selenium supplementation in high-risk cardiac surgical patients undergoing complicated open heart surgery. The investigators hypothesize that the therapeutic strategy tested in this randomized trial may contribute to fewer complications, less organ injury and fewer deaths.

The investigators propose to conduct a randomized, placebo-controlled, double-blind, multicentre definitive trial of 1400 patients across 20 sites in Germany and Canada, which will include the pilot study patients. An industry partner (Biosyn) will provide the product and some additional support for the European sites. Patients will be randomized to receive either a daily perioperative high-dose selenium or placebo until postoperative day 10 (maximum) or upon earlier discharge from ICU. If the hypothesis is proven true, and this simple, inexpensive nutrient reduces complications and improves recovery of patients undergoing cardiac surgery, there is the potential to dramatically change clinical practice and improve health outcomes.

Eligibility Criteria:
Inclusion Criteria:

* Adult patients (\>/=18 years of age)
* Scheduled to undergo elective or urgent cardiac surgery with the use of cardiopulmonary bypass (CPB) and cardioplegic arrest that exhibit a high perioperative risk profile as defined by the presence of one or more of the following:

  * a) Planned valve surgery combined with CABG or multiple valve replacement/repair surgeries or combined cardiac surgical procedures involving the thoracic aorta; OR
  * b) Any cardiac surgery with a high perioperative risk profile, defined as a predicted operative mortality of ≥ 5% (EuroSCORE II).

Exclusion Criteria:

We will exclude patients who meet any of the following criteria:

* Isolated procedures (CABG only or valve)
* Known hypersensitivity to sodium-selenite or to any of the constituents of the solution.
* Renal failure requiring dialysis at the point of screening.
* Chronic liver disease as evidenced by a pre-operative total bilirubin \>2 mg/dl or 34 umol/L.
* Disabling neuropsychiatric disorders (severe dementia, severe Alzheimer's disease, advanced Parkinson's disease).
* Pregnancy or lactation period.
* Simultaneous participation in another clinical trial of an experimental therapy (co-enrolment acceptable in observational studies or randomized trials of existing therapies if permitted by both steering committees and local ethics boards).
* Patients undergoing heart transplantation or preoperative planned LVAD insertion or complex congenital heart surgery.
* Alternate contacts of investigators (required by German Regulatory Authorities).