High-sensitivity Troponin T in Acute Myocardial Infarction After Cardiac Valvular Surgery

A measurable degree of heart muscle tissue injury is expected in patients undergoing heart valvular surgery. The level of this injury can be measured by cardiac biomarkers in blood samples. Those biomarkers are used to diagnose an acute myocardial infarction.

Postoperative myocardial infarction (MI) is a frequent and important complication after cardiac surgery with high morbidity and mortality. Therefore it is very important to recognize any cardiac event in patients who undergo cardiac surgery. Different diagnostic tools can be used to the diagnosis of acute myocardial infarction; however few is known about the value of high-sensitivity cardiac troponin T (hs-cTn) to diagnose a MI after heart valvular surgery.

The aim of this study is to determine the upper reference limit of high-sensitivity troponin T concentration to consider the diagnosis of acute myocardial infarction in patients undergoing heart valvular surgery.

This is a longitudinal prospective observational cohort mono centre study. Hs-cTn will be measured at different point of times in adult patients undergoing heart valvular surgery with cardiopulmonary bypass (CPB) and without recent medical history of ischemic heart disease.

The study is conducted at the University Clinical Hospital of Valladolid, Spain. The Cardiac Surgery department annually performs approximately 550 cardiac surgeries with CPB in adult patients (approximately 300 heart valvular surgeries). Two operating rooms are routinely used. There is an intensive care unit (ICU) with 10 beds dedicated exclusively to the postoperative care of patients who undergo cardiac surgery.The hospital's research commission approved the study. All patients, preoperatively, provided informed written consent both for their heart surgery and for their participation in the study.

Serum levels of hs-cTn will be measured before cardiac surgery, upon arrival at the ICU, as well as every 6 hours for 24 hours, then every 8 hours the following 24 hours and a last blood sample will be taken 72 hours after cardiac surgery. Samples are analysed at the department of Clinical Biochemistry of our hospital.

Twelve-lead electrocardiograms (ECGs) obtained the day prior to heart valvular surgery, immediately upon arrival at the ICU, and then 24, 48 and 72 hours post-surgery will be reviewed by a cardiologist to evidence signs of myocardial infarction (MI). All cardiac events will be noted as The Third Global MI Task Force definition of MI describes.

A transthoracic echocardiography (TTE) will be also performed by a cardiologist after cardiac valvular surgery to determine the ejection fraction of left ventricle and the occurrence of a new regional wall motion abnormality. This TTE will be compared, by the same cardiologist, with a TTE performed before cardiac valvular surgery.

The principal investigator will supervise data handling.

Eligibility Criteria:
Inclusion Criteria:

* Each participant must be older than 18 years.
* Undergoing cardiac valvular surgery.
* No recent clinical history of ischemic heart disease.
* Each participant must voluntarily give his written informed consent.

Exclusion Criteria:

* Patients undergoing coronary bypass artery grafting (CABG).
* Patients with severe or end-stage renal insufficiency.
* Insertion of assist devices.