Postoperative Myocardial Ischemia Clinical Trial
Official title:
Evaluation of a Model for Post-anesthesia Troponin Increase and Heart Injury Estimation
This study evaluates the preoperative cardiovascular risk, the intraoperative hemodynamic characteristics and the surgical photo-plethysmographic index of patients undergoing general anesthesia for non-cardiac vascular surgery to develop a multiple variable model assessing the risk for postoperative myocardial ischemic events.
Perioperative cardiac troponin leak is common and is strongly associated with mortality even
in absence of classic myocardial infarction signs. In the VISION study 11.6% of patients
undergoing non-cardiac surgery were troponin positive and 1.9% (95%CI 1.7-2.1%) of those
patients died within 30 days of surgery. In selected populations of patients undergoing
vascular surgery, a postoperative cTn leak, without clinical features of myocardial ischemia,
is associated with an increased risk of 30-day mortality (odds ratio 5.03, 95% CI 2.88-8.79).
Myocardial oxygen supply-demand imbalance and plaque rupture/thrombosis are the main
mechanism involved in the pathogenesis of postoperative myocardial ischemic events.
Frequently cardiac troponin leaks occur in absence of classical signs and symptoms of
myocardial infarction. More than 80% of patients with postoperative cardiac troponin leak are
clinically asymptomatic for myocardial ischemia, and ischemic ECG changes are often absent.
The identification of patients who will experience a postoperative myocardial ischemia will
continue to be a challenge for anaesthesiologists.The current tool used for risk
stratification using the AHA/ACC algorithm is Lee's Revised Cardiac Risk Index.
Unfortunately, this tool can only reliably exclude low-risk patients and cannot identify
patients which are likely to have perioperative cardiovascular complications.
The surgical plethysmographic index (SPI, GE Healthcare, Finland) during general anaesthesia
has been correlated with the stressors of surgery (e.g. intubation, incision, …), and with
stress hormone production. It has been demonstrated that SPI and other pulse
photo-plethysmographic indices reflect sympathetic-mediated vasoconstriction, thus monitoring
the SPI during general anesthesia could lead to a reduced sympathetic response to surgical
stimuli. Unfortunately there is not a desirable level of SPI, and it is unknown if difference
in SPI values during the surgery might affect the postoperative outcome.
Intraoperative hemodynamic parameters and SPI will be recorded in conjunction with
preoperative cardiovascular risk scores and will be used to develop a multiple variable model
for postoperative risk of myocardial ischemic events.
In this study Electrocardiogram, invasive arterial pressure, photoplethysmography,and
electroencephalographic entropy will be collected continuously from 10 min before induction
of general anesthesia until 20 min after awakening from anesthesia. Gupta's score and Revised
Cardiac Risk Index will be recorded the day before surgery.
Blood samples for high sensitive cardiac troponin T (hs-TnT) assay will be collected on day
of surgery (baseline) and on postoperative day 1, 2 and 3. According to this methodology, in
this study postoperative myocardial ischemic events will be defined as:
1. Myocardial Infarction according to the third universal definition (Thygesen K. et al.
Third universal definition of myocardial infarction. Circulation 2012;126:2020-35 )
2. Myocardial Injury defined a hs-TnT plasmatic concentration of (i) 20-65 ng/L with an
increase >5ng/L between baseline to days 1-3, or (ii) >65 ng/L, or (iii) a rise >50%
between baseline and days 1-3 in case of renal insufficiency, all of them in absence of
non-ischemic causes of troponin increase (sepsis, pulmonary embolism, electrical
cardioversion and acute respiratory failure).
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