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

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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High-sensitivity Troponin T in Acute Myocardial Infarction in Patients Undergoing Cardiac Valvular Surgery

Conditions
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Acute Myocardial Infarction, Disorder; Heart, Functional, Postoperative, Cardiac Surgery, Myocardial Infarction, Heart Valve Diseases

Intervention / Treatment
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* Other: Serum levels of high-sensitivity troponin T
* Other: Twelve-lead ECGs
* Other: Transthoracic echocardiography (TTE)


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: Serum levels of high-sensitivity troponin T|Serum levels of hs-cTn will be measured before 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 surgery.|
|Other: Twelve-lead ECGs|Twelve-lead 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 MI.|
|Other: Transthoracic echocardiography (TTE)|A 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.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Determination of upper reference limit (URL) of high-sensitivity troponin T that strongly suggests substantial myocardial damage and necrosis. | Postoperative MI remains a frequent complication after cardiac surgery with high morbidity and mortality. In 2012 the Third Global MI Task Force presented the third universal definition of MI implying that MI associated with coronary artery bypass grafting (CABG) is arbitrarily defined by elevation of cardiac biomarkers values over 10 x 99th percentile URL in patients with normal baseline cTn values. In addition with either: a) new pathological Q waves or new left bundle branch block (LBBB), or b) angiographic documented new graft or new native coronary artery occlusion, or c) imaging evidence of new loss of viable myocardium or new regional wall motion abnormality. Few is known about the established threshold values for hs-cTn after heart valvular surgery. | Every 6 postoperative hours for the first 24 hours, then every 8 hours the following 24 hours and a last sample will be taken 72 hours after heart valvular surgery. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| High-sensitivity troponin T concentration changes over time in patients undergoing heart valvular surgery | 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 heart valvular surgery. | From 8 hours preoperatively to 72 hours postoperatively | 
| Number of patients with complications after heart valvular surgery. | To determine the number of patients with complications after heart valvular surgery and to determine which are the most frequent complications in patients undergoing cardiac valvular surgery. | After cardiac valvular surgery to 72 hours post-surgery. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Cardiac surgery, high-sensitivity troponin T, Acute myocardial infarction, Heart valvular surgery