What's new?

This retrospective cohort study confirmed that preoperative transthoracic echocardiography abnormalities are common in patients undergoing high‑risk vascular surgery. However, among echocardiographic findings, only myocardial hypokinesis, as compared with normal contractility, was associated with myocardial injury after noncardiac surgery. This study suggests that routine preoperative transthoracic echocardiography may be moderately useful in the prediction of postoperative myocardial injury among patients undergoing high‑risk vascular surgery.

Introduction

Patients with peripheral arterial and aortic diseases (PAADs) and abdominal aortic aneurysms (AAAs) often require open vascular surgery, which presents a unique challenge for perioperative care clinicians.^1,2 These patients are at a risk for postoperative cardiac complications, such as myocardial infarction and myocardial injury after noncardiac surgery (MINS), which, in consequence, have a significant negative influence on prognosis.^3-10

Transthoracic echocardiography (TTE) is a relatively inexpensive, widely available, and noninvasive test that can be used as part of preoperative cardiac evaluation. The current guidelines issued by the European Society of Cardiology (ESC) / European Society of Anesthesiology recommend against routine preoperative TTE in patients who are scheduled for high‑risk surgery, because there is insufficient evidence that it reduces the risk of postoperative major cardiac events or provide more information than clinical risk models.^7,11-13 Nonetheless, TTE is recommended in patients with poor functional capacity, suspected new cardiovascular disease, or unexplained signs or symptoms before surgery.^7,14 Even though previous studies identified several factors associated with increased risk of MINS, to date, there is a lack of high‑quality data on the value of preoperative TTE as a predictor of MINS.⁶

Thus, we conducted this retrospective study with routine perioperative troponin (Tn) monitoring to evaluate whether preoperative TTE abnormalities are linked to myocardial injury in the population of patients undergoing open vascular surgeries involving the abdominal aorta due to AAA and / or PAAD.

Patients and methods

Results

Discussion

This retrospective cohort study provides evidence that routine preoperative TTE in patients undergoing high‑risk vascular surgery often reveals abnormalities. However, their additional value over clinical risk factors in the prediction of MINS is weak or absent. The only preoperative echocardiographic abnormality associated with increased risk of this outcome was myocardial hypokinesis. Even though these results corroborate the current recommendation against the routine use of TTE to predict postoperative cardiac complications, we believe that further prospective studies are warranted to elucidate the role of preoperative TTE in predicting MINS in vascular surgery.

TTE is one of the most commonly performed noninvasive diagnostic tests in cardiology. It provides information on 3 main markers of cardiac structural disease: LV dysfunction, valvular heart diseases, and cardiomyopathies. LV systolic dysfunction is a well‑known predictor of postoperative heart failure.²⁶ Moreover, patients with heart failure diagnosis have increased perioperative mortality, as compared with individuals without heart failure, and lower LVEF is associated with higher 90‑day mortality in this population.^27,28 Nonetheless, LVEF is a borderline independent predictor of major postoperative cardiovascular complications among patients undergoing noncardiac surgery.^29,30 However, it is noteworthy mentioning that those studies were conducted over 25 years ago, when the definition of MINS had not been established yet. In the more recent large study by Park et al,³¹ comprising 1923 noncardiac surgery cases, the echocardiographic parameters, including LVEF, regional wall motion score index, and transmitral early diastolic velocity / tissue Doppler mitral annular early diastolic velocity were predictive of perioperative cardiovascular complications, but none of these parameters was better than the clinically determined RCRI, and they were inferior to a preoperative N‑terminal pro–brain‑type natriuretic peptide measurement.³¹ Moreover, Wijeysundera et al,¹³ based on a study of 264 823 noncardiac surgery patients, demonstrated that preoperative TTE was not associated with improved survival or shorter hospital stay after major noncardiac surgery. Thus, the current European and Canadian perioperative guidelines based mainly on the large abovementioned studies do not recommend routine TTE examination before noncardiac surgery.^7,32 According to those guidelines, poor exercise tolerance, abnormal ECG, suspected new or significant cardiovascular disease or unexplained dyspnea are recommended indications for TTE.

MINS is a common complication following vascular surgery, which increases morbidity and long‑term mortality.^4-7,33 Advanced age, low eGFR, history of CAD, and congestive heart failure are well‑known clinical risk factors of MINS.⁶ Similarly to other studies, patients with CAD, COPD, or a low eGFR were more prone to develop MINS in our study population.^4,6

However, further studies are needed to determine other possible predictors of MINS. The data concerning TTE utility in the prediction of cardiovascular complications, including MINS after vascular surgery, are limited. Flu et al³⁴ demonstrated that open vascular surgery patients with asymptomatic isolated systolic LV dysfunction (defined as LVEF <⁠50% both with and without accompanying diastolic dysfunction) were at an increased risk for 30‑day cardiovascular events and long‑term cardiovascular mortality. Interestingly, Matyal et al³⁵ studied 313 vascular surgery patients by transesophageal echocardiography and found diastolic but not systolic LV dysfunction (defined as LVEF <⁠40%) to be a predictor of adverse cardiovascular outcome.

In a recent study by Kim et al,³⁶ impaired LV global longitudinal strain predicted MINS independently from the traditional risk factors among patients undergoing noncardiac surgery (mostly orthopedic and general). Our study adds to the current knowledge by showing that myocardial hypokinesis is another possible independent risk factor for MINS in patients undergoing high‑risk vascular surgery. It is noteworthy that even discrete regional contractility disorders increase the risk of myocardial injury in patients with preserved LVEF. From a practical point of view, one must remember that individuals with regional hypokinesis and preserved LVEF may not present symptoms such as dyspnea or poor functional capacity, which, according to current guidelines, are potential indications for routine TTE before surgery.⁷ Moreover, the array of noninvasive cardiovascular tests in patients suffering from PAAD is narrower, as their ability to perform stress test is limited due to intermittent claudication or rest pain in the lower extremities. Our study indicates that some TTE markers may be utilized in MINS prediction in this particular group of patients; however, further prospective studies evaluating more modern TTE markers (eg, impaired LV global longitudinal strain) and their clinical usefulness are needed.

Our study has several limitations. Firstly, the study population included a relatively low number of patients with reduced LVEF or severe valvular disease. This is mainly because those patients were qualified for endovascular aortic repair rather than open aortic repair, which is consistent with current guidelines regarding management of abdominal aortic aneurysms.³⁷ Second, not every possible echocardiographic parameter was analyzed (eg, diastolic dysfunction, estimated right ventricular systolic pressure, or tricuspid annular plane systolic excursion).³⁸ Third, preoperative Tn level was not available in all patients. Thus, some incidents of MINS might have been missed. Finally, focusing on patients undergoing high‑risk vascular surgery limits the generalizability of the presented results to all noncardiac surgery populations.