Abstract
Background
Pre-operative echocardiography is performed in selected groups of patients for cardiac risk stratification prior to surgery. Many parameters, including Left Ventricular Ejection Fraction (LVEF), are assessed during echocardiography. While many studies have cited association between low LVEF and poor operative outcomes such as perioperative myocardial infarction or cardiogenic pulmonary edema, LVEF has limitations such as left ventricular (LV) cavity border tracing, geometric assumptions and inter-observer variability. LVEF may also appear normal in the presence of LV hypertrophy and a small LV cavity size. Studies have described the routine use of global longitudinal strain (GLS) as an alternative measure of ventricular function, with GLS having been reported to be a reliable marker in detecting subclinical LV dysfunction. This adds incremental value in predicting myocardial function and in risk stratification. In fact, some studies have documented GLS being a useful preoperative parameter in predicting postoperative LV dysfunction after cardiac valve surgery.
Purpose
The aim of this study is to determine the value of GLS in predicting post-operative outcomes in patients undergoing non-cardiac surgeries.
Methods
This was a retrospective study of all patients who had echocardiography performed for a pre-operative indication from February 2017 to October 2017. These patients were screened for those who had normal LVEF, had undergone subsequent non-cardiac surgery, and had post-operative troponins measured. Medical records were traced for baseline demographics, past medical history and echocardiographic features. GLS evaluation was prospectively performed using TOMTEC-ARENA (TOMTEC Imaging Systems GmbH) by assessors blinded to patient outcomes. Outcomes for major adverse cardiovascular events and mortality up to 1 year post surgery were collected. Post-op myocardial injury was defined as a peak Troponin T value of >30 ng/L or a >20% increment from baseline.
Results
A total of 42 patients were included. 61.9% (n = 26) were male and mean age was 72.3 years. Only 75.6% of patients were fully independent with activities of daily living and mean creatinine was 153.4μmol/L. Mortality at 1 year was 16.7% (n = 7) and 28.6% (n = 12) were deemed to have post-operative myocardial injury. 1-year mortality was associated with a lower GLS (-23.8% vs -19.2%, p = 0.001). However, GLS was not correlated with post-operative myocardial injury or hospital readmissions. In our study population, only a history of past myocardial infarction predicted post-op myocardial injury (58.3% vs 16.7%, p = 0.019).
Conclusion
Our study did not demonstrate the utility of GLS in predicting post-operative events, but this is likely because of the small sample size with low event rates. Nevertheless, GLS values did correlate with 1-year mortality and could be a marker of frailty and an increased mortality risk.
P774 Utility of global longitudinal strain to predict post-operative outcomes in non-cardiac surgery
