Worldwide, the number of individuals with hip fractures is rapidly increasing due to the increasing age of the population. Prior studies documented that most cases who experienced hip fractures were aged 65 years and older. Furthermore, hip fractures in elderly patients is associated with an increased morbidity, mortality, and loss of functional independence, which is becoming a public health burden.1,2 At present, surgical repair is the standard of care, even for the frail patients. In addition, prompt orthopedic intervention within 48h of fractures significantly improved prognosis and reduced mortality.3,4

Transthoracic echocardiography (TTE) provides a qualitative and quantitative assessment of cardiac morphology and function, helping to diagnose specific cardiac pathologies, such as cardiac failure, valvulopathies and hemodynamic status, which cannot be reliably diagnosed through clinical examination.2 A systematic review of echocardiography demonstrated that underlying cardiac pathology detected by echocardiography may alter the clinical evaluation in 17–78% of cases. Therefore, identifying cardiac abnormalities before surgery can improve perioperative management and reduce postoperative morbidity and mortality.5 However, there is also evidence that delaying surgery increases postoperative mortality, constraining the time available for pre-operative investigations.6 Studies have suggested that preoperative TTE may delay surgical repair, thereby increasing the risk of mortality and complications.7–10

Focused TTE is a goal-directed, abbreviated form of echocardiography, which enhances bedside clinical evaluation and guides acute medical decisions without delaying surgery.11 Focused TTE changes clinical evaluation and management by guiding preoperative intravascular volume replacement, and rationalizing the use of invasive monitoring, diuretics, avoid fluid overload, vasopressor infusions and planned postoperative intensive care.6 But the cardiac abnormalities focused TTE should focused on are not yet clear and unified. We sought to identify echocardiographic prognostic indices for elderly patients after hip fractures surgery by evaluating the relationship between cardiac abnormalities derived from preoperative TTE and postoperative mortality, in order to provide reference for focused TTE.

In our study, a total of 724 elderly patients underwent hip fractures surgery between June 2019 and August 2022, of which 687 (94.9%) had preoperative TTE and 18 (2.5%) died in-hospital. A total of 669 elderly patients were included in our final analysis. The clinical characteristics are shown in Table 1. Mean age of them were 78.8 (±8.0) years and 215(32.1%) cases were male. 58 cases of them died within one year after discharge, of which 12 cases (20.7%) died of COVID-19, 7 cases (12.1%) died of cerebrovascular diseases, 7 cases (12.1%) died of Alzheimer's disease,13,14 23 cases (39.6%) died from cardiovascular diseases (8 from heart failure, 10 from arrhythmia, 5 from sudden cardiac death) and 9 cases (15.5%) of unknown causes.

The characteristics of patients who died or survived are listed in Supplementary Table 1. There were no significant differences in gender, fractures type and surgery type between the survivals and postoperative deaths within one year after discharge. Patients with older age and higher ASA score (III, IV vs. I, II) had a higher mortality. As to comorbidities on admission, patients with history of COPD (P=0.001) and AF (P<0.001) had a higher mortality within one year. Patients who died within one year were more likely to have LVEF<50% (10.3% vs. 2.1%, P=0.004), left ventricular dilatation (12.1% vs. 3.3%, P=0.006), PASP>25mmHg (29.3% vs. 7.7%, P<0.001) and moderate-severe AS (5.2% vs. 1.0%, P=0.036) than those who survived.

The following variables were found to be independently associated with mortality within one year in univariate COX regression analysis (Table 2): age (HR 1.065, 95%CI 1.030–1.101; P<0.001), ASA score (III, IV vs. I, II) (HR 1.855, 95%CI 1.098–3.067; P=0.022), history of COPD (HR 4.446, 95%CI 1.909–10.355; P=0.001) and AF (HR 3.803, 95%CI 1.803–8.024; P<0.001), presence of LVEF<50% (HR 5.009, 95%CI 2.151–11.665; P<0.001), left ventricular dilatation (HR 3.813, 95%CI 1.730–8.403; P=0.001), PASP>25mmHg (HR 4.388, 95%CI 2.492–7.725; P<0.001), moderate–severe AS (HR 4.702, 95%CI 1.471–15.035; P=0.009). Supplemental Table 1 shows a multivariate COX regression model including all the above factors. The presence of LVEF<50%, left ventricular dilatation and elevated PASP were proved to be the independent predictors of one-year mortality in elderly patients.

To avoid the problems of overfitting and collinearity, the aforementioned significant predictors (P<0.001) (age, AF, LVEF<50% and PASP>25mmHg) were included in the multivariate COX regression analysis. Results demonstrated that age (HR 1.049, 95%CI 1.013–1.086; P=0.007), history of AF (HR 2.510, 95%CI 1.134–5.557; P=0.023), presence of LVEF<50% (HR 3.815, 95%CI 1.577–9.228; P=0.003) and PASP>25mmHg (HR 2.687, 95%CI 1.449–4.984; P=0.002) maintained the predictive value of mortality within one-year (Table 3). Moreover, model 1(including age, AF, LVEF<50% and PASP>25mmHg) had significantly improved ability to reclassify patients’ risk than model 0 (including age and AF) (IDI=4.3%, P<0.001; continuous NRI=31.4%, P=0.008).

ROC analysis showed that the area under curves (AUC) of model 1 was greater than that of model 0 (0.726 vs. 0.652, P=0.008) (Fig. 1). Kaplan–Meier analysis demonstrated that patients with older age, history of AF, presence of LVEF<50% and PASP>25mmHg had a higher mortality within one-year (Fig. 2).

Fig. 1.

Receiver operating characteristic (ROC) analysis of models to predict the mortality within one year in elderly hip fracture undergoing surgery.

Fig. 2.

Kaplan–Meier freedom from event curves according to (A) age, (B) atrial fibrillation (AF), (C) left ventricular ejection fraction (LVEF)<50%, and (D) pulmonary arterial systolic pressure (PASP)>25mmHg for the elderly patients after hip fractures surgery.

This study found that advanced age, history of AF, COPD were the independent predictive factors of postoperative mortality in elderly patients with hip fractures surgery. Cardiac abnormalities derived from preoperative TTE, apart from LVEF<50% and AS which were commonly mentioned, left ventricular dilatation, and elevated PASP also had prognostic values for elderly patients undergoing hip fracture surgery.

Hip fractures are common in the elderly patients and lead to increased morbidity, mortality, and medical costs.15 Timely surgical repair improves outcomes and quality of life in this population. Before surgical repair, preoperative cardiac evaluation must consider the risk-benefit ratio. TTE is a useful non-invasive investigation for screening and assessment of cardiac disease and risk. Several studies have found that preoperative TTE significantly lengthens the time to surgery and does not improve the survival of patients.7,9,16 A retrospective, nationwide cohort study in Japan demonstrated that preoperative echocardiography was not associated with reduced in-hospital mortality or postoperative complications.2 In addition, preoperative echocardiography in patients with hip fractures has been found to be associated with increased mortality at 90 days and 1 year.7,17 But, cardiac abnormality detected by preoperative TTE such as aortic stenosis or left ventricular dysfunction did alter preoperative consultations and targeting invasive monitoring to improve patient outcomes.18–20 Patients with cardiac abnormality of preoperative TTE did indeed receive different care, which avoids the occurrence of adverse events.21

In recent studies, focused TTE was found to be feasible, not to delay surgery and frequently influence diagnosis and management by identifying important cardiac disease and hemodynamic abnormalities.11,22 However, most of the articles were observational studies with inherent design flaws. A small prospectively randomized study demonstrated that preoperative focused TTE led to important changes in treatment, such as more rational use of invasive monitoring, vasopressor infusion and postoperative intensive care in patients with hip fractures.6 At present, the studies on cardiac abnormalities that focused TTE should pay attention to are not comprehensive. A prognostic study of elderly patients with intertrochanteric fractures demonstrated the predictive value of LVEF, AS, and LVEDD for one-month and one-year mortality.16 A study in China revealed the predictive value of preoperative TTE for major cardiac events and in-hospital mortality in elderly patients with hip fractures and proposed cardiac abnormalities including LVEF<50% and AS.23

Consistent with previous research, our data confirmed that LVEF<50% remained predictive value for mortality in aged patients with hip fractures surgery.16,18 Another preoperative cardiac predictor that increased the mortality in patients undergoing hip fracture surgery is elevated PASP. PASP has been found to be a predictor of in-hospital mortality in elderly patients with hip fractures.1 Our study suggested that PASP>25mmHg is a predictive factor for one-year mortality after adjusting for age, atrial fibrillation and LVEF<50%. The PASP elevation has been shown to be associated with fat embolism and venous thromboembolism in elderly patients.24,25 Pulmonary hypertension is a common complication of COPD and sleep apnea.26,27 In addition, direct connection between elevated PASP and right ventricular failure has been reported in a prior study.28

In addition, we found a patient with left ventricular dilatation had an increased risk of one-year mortality (HR: 3.813, 95% CI: 1.730–8.403, P=0.001). Increased LVEDD has been correlated with dilated, ischemic, or hypertensive cardiomyopathy, ventricular septal defect, and mitral/aortic regurgitation. Dilated left ventricle with a thinner myocardial wall predisposes heart to diastolic and systolic dysfunction, diminished coronary artery circulation and ventricular dysrhythmias.29 Moreover, left ventricular capacity overload can lead to pulmonary edema and lung infection. Our research also found that AS had predictive value for one-year mortality (HR: 4.702, 95% CI: 1.471–15.035, P=0.009). This may be due to hemodynamic instability. AS resulted in decreased left ventricular compliance and coronary reserve.

In our study, the presence of AF was found to be an independent preoperative cardiac risk factor of the in-one-year mortality. AF is the most encountered arrhythmia in clinical practice and its frequency significantly increases with age. Previous studies have shown a close relationship between AF and thromboembolic events, cardiac failure, decreased motor ability, depression, and cognitive impairment in elderly patients.1 Therefore, it is reasonable that patients with the presence of AF could have a higher risk of worse outcomes and mortality. In addition, our data revealed that history of COPD were associated with an increase in one-year mortality. COPD is known as a risk factor for chronic PASP elevation,24 and also is associated with respiratory failure, which may be the way it increases mortality.

The major limitation is that this study was a single central retrospective analysis, which might be related to selection bias. We minimized the bias in patient enrollment by using data from an electronic medical record database. The patients involved were elderly patients with preoperative TTE, so our results cannot be directly applied to all patients undergoing hip fracture surgery. Further multicenter, prospective studies with larger population are needed to confirm the study's results.

Our research suggested that elderly patients undergoing hip fracture surgery with a history of AF and a presence of elevated PASP might require closer follow-up, a careful fluid management and anti-coagulant treatment, even without LVEF<50% or AS. We consider that these indices including LVEF, AS, LVEDD and PASP would be clinically important regarding the preoperative cardiac risk assessment of elderly hip fracture patients who are treated with surgery, which may be assessed in the focused TTE.

WML and YG designed the study and completed the analysis and manuscript. KHF and JWZ helped with data collection and arrangement. All authors read and approved the final manuscript.

Ethics committee of Shanghai Sixth People's Hospital approved this research (ethic code number: 2023-161). Our study was conducted in accordance with the principles of the Declaration of Helsinki 1975, as revised in 2008.

Not applicable.

No funding was received to assist with the preparation of this manuscript.

The authors report no conflicts of interest in this work.

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.