Minimal invasive imaging of coronary artery disease in patients with asymptomatic myocardial injury after major non-cardiac surgery.

see also the introduction section of the protocol.
Early peri-operative troponin elevation after non-cardiac surgery is a strong
predictor of short and midterm adverse outcome. The diagnosis of peri-operative
myocardial injury using troponin assays is known since the early nineties and
its prognostic value is established now. However, intervention studies to
improve prognosis of patients with peri-operative myocardial injury have not
been conducted so far. A main limitation in this regard is the lack of
knowledge about the pathofysiologic mechanisms behind postoperative troponin
elevation.
We hypothesize that novel minimal invasive cardiac imaging techniques such as
coronary CT-angiography and MRI may be of help to estimate the risk of coronary
artery disease as a cause of peri-operative myocardial injury. Identification
of patients with coronary artery disease in the immediate postoperative period
allows anti-ischemic therapy for prevention of future adverse events.

Primary objectives

To quantify coronary artery disease, determined by minimal invasive imaging
techniques, as a cause of post-operative myocardial injury in patients
undergoing non-cardiac surgery.

Secondary objective
To correlate coronary calciumscore to post-operative troponin levels.

Study design
This is a prospective observational study, designed to assess coronary artery
disease with minimal invasive techniques, i.e. without classic coronary
angiography, in patients with peri-operative myocardial injury after
non-cardiac surgery.


Inclusion criteria:
1. Non cardiac surgery with a planned minimal postoperative hospital stay of 2
nights
2. Elective or emergency surgery
3. Age > 60 year.
4. Troponin-I elevation in the first 3 post-operative days: > 0.01 ng/ml.
5. No clinical symptoms of myocardial ischemia.


Exclusion criteria:

1) Perioperative troponin elevation due to other factors than coronary artery
disease such as proven pulmonary embolism or sepsis.
2) Perioperative ST-elevation myocardial infarction (STEMI)
3) Perioperative symptomatic angina with troponin elevation
4) Patients with a history or ECG-signs of myocardial infarction
5) Patients with pre-existent heart failure, left ventricular dysfunction,
significant valvular disease or left ventricle hypertrophy.
6) Patients with significant valvular disease or left ventricle hypertrophy
determined post-operatively with echocardiography.
7) Contra-indication for CMR such as claustrophobia or metal prosthesis.
8) Allergic reaction to CT-contrast or gadolinium.
9) Renal dysfunction with GFR < 30 ml/min, as determined after the operation
10) Unstable hemodynamics or other conditions disabling transport to the
Radiology department.
11) Expected major discomfort or substantial increase in pain sensation at the
time of undergoing CCTA or CMR.
12) Admission at the ICU
13) Poor prognosis due to other medical conditions e.g. malignancy
14) Second or third degree atrio-ventricular block on the ECG

Both cardiac imaging techniques are minimal invasive with a low risk of an
anaphylactic reaction and kidney function depression due to the contrast use
with the CCTA.
Patients are excluded beforehand if known with allergic reactions on contrast
agents
and if known with severe renal failure. Nonetheless, patients are admitted in
the hospital
and any adverse reaction in relation to the study procedures will be documented
and reported
to the METC and CCMO. Some patients will undergo the MRI in an outpatient
setting, according to a standard care protocol.