Abstract

Frailty syndrome (FS) is one of the most important variables that have a proven impact on the increased risk of morbidity and mortality in cardiac surgery. However, FS assessment is not routinely incorporated into daily clinical practice or included in commonly used risk assessment models. The inclusion of FS in perioperative risk prediction models in cardiac surgery would not only allow for a more accurate assessment but could also assist in the selection of an appropriate treatment strategy while favoring the appropriate use of clinical resources. The identification of FS in the qualification process must not be seen as an absolute contraindication to cardiac surgery but as an opportunity to adequately prepare the patient for the procedure. However, the literature is heterogeneous in terms of the selection of an appropriate tool for identifying FS. Selected tools commonly used in the assessment of FS in patients with cardiovascular disease, including those of greatest relevance in cardiac surgery, are presented in this editorial.

Key words: cardiac surgery, frailty syndrome, older adult, perioperative risk

Introduction

Cardiac surgery is currently facing a preponderance of older adult patients with coexisting frailty syndrome (FS), which poses significant clinical, social and economic challenges.¹ Worldwide, there has been a deterioration in the clinical profile of patients qualified for cardiac surgery. Indeed, patients are characterized by higher than before perioperative risk and more comorbidities, with the average duration of surgery and stay in the postoperative ward increasing.² The qualification and perioperative risk stratification should consider all variables that will determine treatment outcomes in the short and long term. Frailty syndrome is one of the most important variables that have a proven impact on the increased risk of morbidity and mortality in cardiac surgery.^{3, 4} However, FS assessment is not routinely incorporated into everyday clinical practice or included in commonly used risk assessment models, such as The European System for Cardiac Operative Risk Evaluation II (EuroSCORE II) or The Society of Thoracic Surgeons (STS) risk score. In clinical decision-making, frailty is still assessed using unstandardized methods, either at the bedside (e.g., foot-of-the-bed assessment) or by using the so-called “eyeball test”.⁵ However, these rapid and subjective assessment methods are not reliable for assessing frailty.⁶ There is still no consensus on a specific multidimensional tool for assessing FS in cardiac surgery that has a high-risk predictive value. Incorporating FS into perioperative risk prediction models in cardiac surgery would allow for a more accurate assessment and help select an appropriate treatment strategy while promoting the appropriate use of clinical resources. Importantly, these risk scales can aid during Heart Team discussions to ensure balanced multidisciplinary decision-making in cardiac surgery, especially in line with the patient’s goals and values. The overarching goals of cardiac surgery management should always be patient-centered. Cardiac surgery is designed to alleviate symptoms of disease and improve patient survival. The identification of FS in the qualification process must not be seen as an absolute contraindication for cardiac surgery, but rather an opportunity to adequately prepare the patient for this procedure. Given the high importance of FS in cardiac surgery, it is important to continue research efforts aimed at improving models that predict perioperative risk, as well as to implement routine assessment of FS during the qualification process. The literature, however, is heterogeneous in terms of choosing an appropriate tool for identifying FS. This is due to the development and availability of multiple research tools, as well as the existence of different approaches to operationalizing frailty. Broadly speaking, there are unidimensional tools for assessing frailty, most often physical frailty, and multidimensional tools that assess frailty in both physical and psychosocial aspects.

Commonly used assessment tools

A selection of commonly used tools for assessing FS in patients with cardiovascular disease, including those of greatest relevance in cardiac surgery, are described below.

The 5-meter gait speed is often used in research studies of cardiac surgery as a tool that reliably predicts the risk of perioperative complications. Walking a distance of 5 m in ≥6 s is considered a slow gait speed.¹⁰ Many researchers recognize the superiority of this test over others in predicting perioperative complications in cardiac surgery.⁷

The frailty phenotype consists of 5 criteria to identify frailty, including weight loss, feelings of exhaustion, decreased physical activity, slowed gait speed, and weakened handgrip strength. Frailty is diagnosed when a minimum of 3 criteria are met, whilst meeting from 1 to 2 criteria indicates pre-frailty, a condition predisposing to frailty.⁸

The frailty index was developed from the Canadian Study of Health and Aging. It assesses the accumulation of deficits such as decreased mobility, cognitive impairment, reduced energy and functional capacity, worse mood, lack of social support, unintentional weight loss, and loss of appetite, among others.^{9, 10}

The Clinical Frailty Scale involves clinically assessing patients and classifying them into one of 9 states, where No. 1 means that the patient is very fit, and No. 9 means that the patient is terminally ill and has a life expectancy of less than 6 months. Each score on the scale corresponds to a written description of frailty that is supplemented by a corresponding graphic to support the frailty classification. A score ≥5 indicates frailty.¹⁰

The Tilburg Frailty Indicator is a multidimensional assessment tool for FS. It consists of 25 questions and provides data on general frailty, as well as frailty in terms of physical, mental and societal domains. Frailty is recognized with a score ≥5 points.^{11, 12, 13}

The Groningen Frailty Indicator is a multidimensional tool composed of 15 items that include physical, cognitive, social, and psychological factors. Scores range from a minimum score (0 points) to a score ≥4 points, which indicates frailty.¹⁴

The simple frailty questionnaire (FRAIL) scale consists of 5 items that address subjective feelings of fatigue, difficulty walking 10 steps without resting, difficulty walking several hundred meters, chronic disease, comorbidities, and unintentional weight loss. Frailty is identified when from 3 to 5 elements are reported, whilst pre-frailty is diagnosed when 1 to 2 elements are reported.¹⁵

The Edmonton Frail Scale takes into account the assessment of cognitive function, general health, functional independence, social support, medication intake, nutritional status, mood, incontinence, and functional capacity. The scores range from 0 (no frailty) to 17 (severe frailty).¹⁶

The Essential Frailty Toolset predicts the annual risk of death in patients scheduled for either transcatheter or surgical aortic valve surgery. The tool assesses preoperative anemia, hypoalbuminemia, 5 repetitions of standing up from a chair to a standing position without the use of arms, and cognitive impairment. A score of 5 indicates a high risk of 1-year mortality (65% for transcatheter and 50% for surgical), whilst a score of 0–1 indicates a risk of 1-year mortality of 6% for transcatheter and 3% for surgical intervention.¹⁷

Comprehensive assessment of frailty was introduced as a more precise preoperative assessment of frailty in elderly cardiac surgery patients. This assessment includes elements specific to the frailty phenotype and clinical frailty assessment. In addition, it assesses performance in basic and complex activities of daily living, balance and physical fitness. It also includes the results of laboratory tests (albumin, creatinine, natriuretic peptide) and takes into account the functional status of the respiratory system.¹⁸

Frailty Predicts Death One Year after Elective Cardiac Surgery Test (FORECAST) is a simplified version of the comprehensive assessment of frailty, consisting of 5 items with the highest predictive value. Tests involve sitting down and getting up from a chair, patient-declared feelings of weakness within 2 weeks, climbing stairs, assessment using the Clinical Frailty Scale, and serum creatinine level. This assessment has shown promising results in predicting annual mortality in the cardiac surgery patient population.¹⁹

Conclusions

Identification of FS in cardiac surgery may have different practical purposes. Screening tools are appropriate for perioperative risk stratification, while formal, in-depth FS assessment may be necessary to define specific and individualized preoperative management to optimize the patient’s condition and reduce complications.²⁰ In an ideal clinical setting, FS assessment tools should have the ability to differentiate between potentially reversible frailty and irreversible frailty. This aims to enhance the identification of patients who may not only be candidates for cardiac surgery but are also highly likely to survive it while maintaining or improving their quality of life.^{21, 22}

Table 1 shows issues related to the assessment of frailty in cardiac surgery. Table 2 presents selected methods used to assess frailty in cardiac surgery.