Clinical guidelines reduce unnecessary preoperative echocardiograph in elderly hip fracture patients

Background The American College of Cardiology (ACC) and the American Heart Association (AHA) have set up guidelines for preoperative usage of transthoracic echocardiograph (TTE) in case of non-cardiac surgery. Unnecessary TTE would increase hospital cost and delay surgery. Therefore, we aimed to analyze whether the TTE before hip fracture surgery was in accordance with guidelines and what the effects were on outcome. Methods 281 elderly patients who had surgery for an isolated hip fracture were involved. The preoperative TTE test and adherence to the guideline were analyzed. TTE reports were reviewed for the presence of major cardiac abnormality with potentiality to change perioperative management, including left ventricular systolic or diastolic dysfunction, pericardial effusion, moderate or severe valvular disease, and pulmonary hypertension. Primary outcome was time to surgery (TTS), length of hospital stay (LLS), postoperative complications. Secondary outcome was sensitivity and specificity of accordance with the guideline for identifying which patients would have TTE that demonstrated major cardiac abnormality. Results Of the 281 patients included, 174 patients (61.9%) received the TTE, whereas 107 patients did not. Only 71 of the 174 patients (40.8%) with TTE met the guidelines. Among the 202 patients who did not meet the guidelines (103 with TTE and 99 without TTE), those who received a preoperative TTE had a longer TTS (4.24 vs. 2.10 days, P = 0.000) and LOS (10.44 vs. 7.72 days, P=0.000). There were no differences in postoperative complication, the sensitivity and specificity of guidelines as the screening tool to identify patients with major cardiac abnormality was 86.7% and 68.7%. Conclusion Preoperative TTE is frequently overused out of guidelines and lead to unnecessary surgery delay while not reducing the rate of postoperative complications. Stricter adherence to guidelines should be recommended, as it would help decrease


unnecessary test.
Background Hip fracture is the major reason of hospital admission in elderly patients. With a constantly increasing incidence, it is estimated to reach 6.3 million worldwide by the year 2050 [1]. Elderly patients with hip fracture commonly presented with multiple comorbidities associated with high morbidity and mortality rates [2,3]. Cardiovascular complications were the principal causes of death after hip fracture [4,5]. On the one hand, early surgical intervention is commonly recommended for hip fracture patients as the surgery delay is associated with increased complications and mortality [6,7]. On the other hand, early surgery is often delayed due to preoperative cardiac risk assessment and stratification. This may involve the preoperative transthoracic echocardiography (TTE) as it is often time consuming. Therefore, extended preoperative TTE should be restricted if it is unlikely to identify the major cardiac abnormality or change perioperative patient management. In 2014, the American College of Cardiology (ACC) Foundation and the American Heart Association (AHA) developed guidelines to determine which patients require preoperative TTE in non-cardiac surgery [8]. The guidelines aimed to identify patients who were most likely to demonstrate major cardiac abnormality on TTE and consequently reduce unnecessary test. Despite the existence of guidelines, the gap between guideline and clinical practice often exists [9]. In addition, the appropriateness of this guidelines in the management of elderly patients with hip fractures was not established. Therefore, we aimed to identify how often preoperative transthoracic echocardiograph (TTE) is made in accordance with the guidelines and the influence caused by the unnecessary TTE. In addition, to assess whether the guidelines decrease TTE without missing the important cardiac disease.

Study population
After institutional review board approval, we retrospectively reviewed the electronic medical records of surgically treated hip fractures (femoral neck, intertrochanteric, subtrochanteric) in elderly patients from January 1, 2015 to January 1, 2018. Exclusion criteria including (1)

Whether adhere to guideline or not
For each patient included, charts were reviewed whether it was recommended to undergo TTE or not according to ACC/AHA guidelines. The indications for undergoing TTE included (1) dyspnea of unknown origin, (2) worsening of known signs or symptoms of heart failure, (3) known history of valvular dysfunction or heart failure without TTE in the last year or worsened symptoms, and (4) suspicion of moderate or greater valvular stenosis or regurgitation. [8] If the patient met one or more of the indications above, it was determined that the patient should undergo TTE. As a result, the patients were divided into 4 groups, including patients met the ACC/AHA guideline and underwent TTE; patients did not meet the guideline but undergo TTE; patients met the guideline but did not undergo TTE; patients did not meet the guideline or undergo TTE.

Major cardiac abnormality
Additional analyses with the subgroup of patients with a preoperative TTE was conducted.
The preoperative TTE report was reviewed to identify whether there was major cardiac abnormality with potentiality to change perioperative management. According to previous literature, these conditions included a left ventricular ejection fraction diminished by <25%, systolic pulmonary artery hypertension >55 mm Hg, "moderate" or "severe" valvular disease and pericardial effusion. [10][11][12] The TTE was defined to have the potentiality to change management if it had one or more of major cardiac abnormalities listed above.

Statistical analysis
Continuous variables are expressed as mean ± standard deviation and compared using Student's t test between those who did not meet the guideline but underwent TTE and those who did not meet the guideline or undergo TTE. Categorical variables are expressed as percentages and compared using the Chi-squared test or Fisher exact test as appropriate between 2 groups. The assessment of the ACC/AHA guideline as a screening tool was evaluated by calculating sensitivity and specificity for identifying patients in whom TTE would demonstrate major abnormality that would change management. Data were analyzed using SPSS (version 20.0; SPSS, Chicago, IL, USA). Statistical significance was defined as a value of p < 0.05.

Results
In total, 324 elderly patients (≥65-year old) with hip fracture were surgically treated in our hospital during the study period. After reviewing the electronic medical records, 43 patients were excluded (5 with multiple fractures, 6 with pathological fracture, 3 with peri-prosthetic fracture, 16  Further analysis of the patients who did not meet the ACC/AHA guidelines was conducted, comparing those who underwent TTE (n = 103) and those who did not (n =99). There were no statistically significant differences in age, gender, or fracture or ASA class or anesthesiology type or treatment type. Most participants were female, and the most common fracture type was femoral neck. The majority of patients were treated using hemiarthroplasty ( Additional analyses with the subgroup of patients with a preoperative TTE explored how frequently TTE reveals cardiac abnormality with potentiality of changing management and whether application of guidelines to indicate TTE was practicable or not. The rate of adherence to the ACC/AHA guideline was 40.8% (n=71). The most common indications for the TTE performed in adherence to the guidelines were known heart disease and over 1 year since the last TTE (n=37), heart murmur (n=17), known heart disease with worsened symptoms (n=7), and dyspnea of unknown origin (n=10). The rest of TTE was ordered for generic "evaluation of cardiac function" although the patient did not show related cardiac symptoms. After reviewing 174 TTE reports, 30 patients were identified by the TTE as having cardiac abnormality with the potentiality to alter perioperative management, including moderate-severe valvular disease (n=13), pulmonary hypertension (n=7), decline in ejection fraction (n=5), moderate-severe pericardial effusion (n=5). Only 4 patients were identified as having major cardiac abnormality among 103 patients who underwent TTE out of guidelines, whereas 26 patients were identified as having major cardiac abnormality among 71 patients whose TTE was adherent to ACC/AHA guideline. As a result, the guidelines were the accurate screening tool to identify patients with major cardiac abnormality with a calculated sensitivity of 86.7 % and a specificity of 68.7% (Table 4).

Discussion
Though the ACC/AHA guidelines set up the standard algorithm for preoperative cardiac assessment in non-cardiac surgery, its adherent rate was not known. In this study, we confirmed that preoperative TTE in elderly patients with hip fracture is frequently not according to these guidelines in daily practice. A large number of patients are receiving unnecessary preoperative TTE without detecting the major cardiac abnormality. Although no significant difference in postoperative complications was identified, those patients with preoperative TTE out of guideline had the longer time to surgery and longer total hospital length of stay.
Based on the ACC/AHA guidelines, the patients who require noninvasive cardiac testing are those with active high-risk cardiac conditions. High risk patients might benefit from delaying hip fracture surgery to assess or clear the cardiac comorbidities [8]. However, delaying surgery due to unrecommended TTE could lead to worse outcome [13]. As our results showed, patients who had the TTE out of guidelines had higher prevalence of chronic obstructive pulmonary disease compared with the patients without TTE. However, there was no significant difference in cardiac related factors, including history of cardiovascular disease or ASA class. One possible explanation was that the indications for TTE were unclear and were rarely adherent to guidelines in clinical practice. Thus, a standardized protocol to determine which patients should undergo TTE was extremely valuable in clinical practice.
Unnecessary surgery delay( 48h) increases the perioperative complications and mortality [14]. Patients without preoperative TTE was closed to this target time; however, those with TTE out of guideline were delayed almost 2 days. Previous studies have also shown a growing concern with surgery delay due to preoperative cardiac test. Luttrell [17]. Therefore, we need to balance the benefits of TTE for preoperative cardiac risk assessment and the morbidity caused by surgery delay. High risk patients may benefit from delaying hip fracture surgery to undergo TTE and optimize the cardiac comorbidities.
However, delaying surgery with a preoperative TTE that is not recommended or contributing may lead to worse outcome. Although ACC/AHA guideline had set up the criteria to determine which patients need preoperative TTE in non-cardiac surgery, its accuracy of acting as a screening tool to identify high risk patient with major cardiac abnormality was rarely studied. Our study demonstrated that the sensitivity of ACA/AHA guidelines for identifying patients who may have major cardiac abnormality with the potential to modify anesthesia or medical management was as high as 86.7% and the specificity was 68.7%. Our results supported those of a similar study from Chris et al, they reviewed 100 patients with preoperative TTE and found 66% was in accordance with the guideline. The sensitivity and specificity of guideline for identifying patients who may have cardiac abnormality were 100% and 40%. [18] These guidelines were also proved to be effective to prevent the overuse of the other cardiac test. Stitgen et al. found that only 29% of geriatric patients with hip fracture who received a cardiology consultation had met the ACC/AHA guidelines and the consultation out of guideline did not change perioperative management but caused prominent surgery delay [19]. Smeets et al. conducted a retrospective study involving 388 patients and found the most frequent reason for incorrect preoperative cardiac screening was overscreening.
In addition, the delay to surgery was increased by 9.9 h in the case of overscreening [20].
Recently, Smeets et al. published the prospective study involving 166 hip fracture patients and 87% of patients received preoperative cardiac screening in adherence to guideline, which was associated with a diminished use of preoperative resources [21].
To our best knowledge, there was only one study evaluating the correspondance between guideline and TTE utilization before [18]. However, they divided the patients into 2 groups (with TTE and without TTE) without further subdividing based on whether adhering to guidelines or not. The further subdivision could eliminate other unwanted distrubance, making the result difference more solely caused by TTE out of guideline. In addition, the pericardial effusion was not regarded as the abnormality with potentiality to change management, but it was proved to affect perioperative management in recent study [11].
Our study showed implementation of guidelines could improve the approriate usage of preoperative TTE test, reduce unecessary surgery delay. Several limitations should be noticed when interpreting these results. Firstly, surgery delay is multifactorial not solely caused by the TTE test, however we tried to minor the bias by excluding patients with surgery delay due to the unavailability of an operating room, surgeon or anticoagulant withdrawl. Secondary, evaluating whether TTE was adherent to guideline or not was subjective, but we decreased the bias by assessing the cases by two iddependant observers (X.P.C, Y.C.M) blinded to the TTE result and disscussed with the third observer(QT.L) when they have different opinions and drawed the conclusion finally.
Thridly, we mainly focused on whether TTE identify major cardiac abnnormality which was     Figure 1 Preoperative TTE and ACC/AHA guidelines status for 281 hip fracture patients.