Abstract
The volume of patients who are older and living with frailty presenting for surgery is increasing. Frailty is a multifactorial clinical syndrome associated with decreased metabolic and physiological reserve across multiple organ systems. Frailty increases vulnerability to morbidity, loss of independence, and death in the perioperative period. Data suggest that frailty is prevalent within the vascular surgical population, itself a high-risk group. As a result, identifying patients living with frailty presenting for vascular surgery is of utmost importance. In this article, we discuss what is currently known about the burden of frailty in the vascular surgical population, how to identify those living with frailty preoperatively, the optimization of frailty, and their intra- and postoperative care.
By reading this article, you should be able to:
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describe the frailty syndrome
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summarize the tools used to identify frailty
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describe methods to optimize frailty
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consider how frailty may impact surgical and anaesthetic decision-making in the vascular population
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formulate an approach to the perioperative care of patients living with frailty
Introduction
The surgical population is ageing, and the patients we care for are becoming increasingly complex. , Whilst ageing and frailty are linked but distinct processes, the rise in older patients presenting for surgery is increasing the number of patients living with frailty in our surgical populations, and frailty is a key risk factor for life-changing morbidity and mortality following major surgery. The picture for patients requiring vascular surgery is even more striking. Recent data from the UK suggest that around 80% of patients presenting for vascular surgery are American Society of Anesthesiologists (ASA) 3 or more (vs 30% for the rest of adult patients in all other specialties). Whilst around 25% of all patients over 65 coming for surgery are clinically frail, this rises to around 45% in the vascular surgery group. Given that frailty is common and associated with poor outcomes, it is essential to detect it, highlight the risk, and modify perioperative care appropriately.
What is frailty?
Frailty reflects a state of increased vulnerability coupled with diminished capacity to respond to stressors, resulting in increased adverse health outcomes for individuals of the same chronological age.
Two models have been described for defining and measuring frailty. First, the phenotype model was described by Fried and colleagues and validated by the Cardiovascular Health Study. This model is based on five pre-defined phenotypic criteria: sedentary behaviour, poor grip strength, decreased gait speed, unintentional weight loss, and low energy levels ( Table 1 ). The presence of one or two abnormalities indicates the patient is pre-frail, whilst three or more indicates frailty.
| Frailty characteristic | Cardiovascular Health Study measure |
|---|---|
| Weight loss | Unintentional loss of >4.5 kg/10 lb over the last year |
| Weakness/fatigue | Handgrip strength in the lowest 20% quintile adjusted for sex and body mass index (BMI) |
| Slowness | Walking speed under the lowest quintile adjusted for sex and BMI |
| Exhaustion | Self-reported exhaustion based on the centre for epidemiologic studies depression scale |
| Low physical activity level | Self-reported lowest quintile of kcal/week as measured by the Minnesota leisure activity scale |
| Frailty scale: No abnormality = Fit 1–2 abnormalities = Pre-frail 3 or more abnormalities = Frail | |
In contrast, the Frailty Index model, also referred to as the Cumulative Deficit model, was developed by Rockwood and colleagues and validated by the Canadian Study of Health and Aging. The model is based on the accumulation of deficits associated with the ageing process over time. It incorporates 92 variables, including comorbidities, daily activity, health attitude, function, and nutrition, and each domain represents a potential deficit. Increasing accumulation of deficits is associated with an increasing ‘frailty index’ and, therefore, a greater risk of adverse health outcomes.
Identifying frailty
Multiple frailty screening tools are available. Many are validated in the general geriatric population, with less specifically for identifying frailty in the surgical, or even vascular surgical, patient. In patients being worked up for surgery, the Centre for Perioperative Care (CPOC) recommends reviewing primary care assessments of frailty. Frailty should then be reassessed in the preassessment clinic using a validated tool. Those who are identified as living with mild frailty or above should undergo a review with a perioperative team experienced in the management of frail patients.
All patients aged 65 and over are screened for frailty in the UK. The electronic frailty index (eFI) is used, and automatically generates a score from primary care electronic health records based on 36 ‘deficits’ which may indicate frailty, including activity limitation, arthritis, and being housebound. However the eFI is not diagnostic and should be used as a risk stratification tool. An elevated eFI should lead to further assessment to confirm frailty. It has yet to be fully validated in the perioperative patient, but recent research suggests that increasing eFI is associated with increased odds of adverse postoperative events using a composite outcome measure that includes mortality, readmission, and return to the emergency department.
The Clinical Frailty Scale (CFS) and Edmonton Frail Scale (EFS) are well-validated, easy to use, and reproducible. Developed by Rockwood and colleagues, the CFS is a judgement-based tool that uses a nine-point pictorial scale with descriptive anchors used to screen for frailty and stratify the degrees of fitness and frailty. A score between 1 and 3 represents patients who are not frail, 4 indicates vulnerability and scores from 5 to 9 represent increasing levels of frailty from mild to terminal illness. It is easy and quick to score with minimal training and reproducible. It is used frequently and has validation in this perioperative population. The EFS has a strong evidence base and incorporates nine frailty domains ( Table 2 ). From the nine domains, a final score is calculated classifying patients as not frail, vulnerable, or with mild, moderate, or severe frailty. It is more time-consuming than the CFS but is often used for research studies.
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More complex still is the Comprehensive Geriatric Assessment (CGA), a multi-dimensional assessment tool that is the gold standard for screening, diagnosing, managing, and optimizing frailty. It assesses medical issues, mental health, functional capacity, social circumstances, and the patient’s environment to build a complete picture of the patient. It is widely used in geriatric medicine. However, this tool is complex, resource-intensive, and requires specialist skills and multidisciplinary team (MDT) engagement, which may limit routine use in time-constrained preoperative assessment clinics. Despite this, there is emerging evidence for its clinical and cost-effectiveness in elective and emergency perioperative settings.
Preoperative optimization of frailty
Guidance published in 2021 by the Centre for Perioperative Care (CPOC) in collaboration with the British Geriatric Society (BGS) advocates using perioperative care pathways for patients with frailty presenting for elective and emergency surgery. They highlight the importance of multidisciplinary working between surgeons, anaesthetists, and specialists in geriatric medicine to optimize co-existing medical conditions, medication, physical activity, and geriatric syndromes such as sarcopenia, malnutrition, and cognitive impairment. This standard of care is available in some units in the UK (e.g. The Proactive Care of Older People Undergoing Surgery (POPS) service set up by the team at Guy’s and St Thomas’ NHS Foundation Trust and the Ortho-geriatric Model of Care for hip fracture patients and the Systematic Care Older Patients Undergoing Elective Surgery (SCOPES) set up by Nottingham University Hospitals NHS Trust). These services take time and resources to set up, and these pioneering teams have helped other centres build similar pathways. Even if this service is not deliverable in all units, a focused preoperative evaluation identifying patients living with frailty at increased perioperative risk is essential to plan individualized optimization strategies, make informed treatment decisions and effectively utilize critical care resources.
At our centre, we run weekly anaesthetic consultant-led vascular preoperative assessment clinics, including a detailed medical and social history, clinical examination, CFS score assessment, supplemented with pulmonary function tests, electrocardiogram, and cardiopulmonary exercise testing where indicated. This assessment contributes to a weekly vascular surgery MDT that includes vascular surgeons, vascular anaesthetists, and interventional radiologists. Notably, regular providers of preassessment for vascular surgery can make an ‘initial clinical impression’ or ‘gut instinct’ on fitness to undergo surgery based on the first 1 minute of meeting a patient and a brief notes assessment that has a hazard ratio of 2.14 for predicting mortality – first impressions do count even if we have limited objective information. All patients assessed for major elective vascular surgery are discussed, and the treatment options are planned. The outcome of the MDT meeting is shared and discussed with the patient, therefore allowing for an opportunity for the patient to make an informed decision about their treatment options. All high-risk patients who decide to proceed with surgery, are offered the chance for referral into our local PREP-WELL multi-modal community prehabilitation programme, for optimization of health and well-being before major elective surgery.
Here we highlight some aspects of frailty that may be modified with this approach.
Sarcopenia
Sarcopenia is a complex multifactorial age-related loss of skeletal muscle mass, quality, and function and is an independent predictor of adverse perioperative outcomes following vascular surgery – physical disability, poor quality of life, increase in all-cause mortality and major lower limb amputation. , Sarcopenia is highly prevalent in vascular surgical patients, with a particularly high prevalence of 25% in patients with peripheral arterial disease (PAD).
Sarcopenia may be identified in the clinical history, by examination, and via screening tools (e.g. the SARC-F questionnaire for ‘strength, assistance with walking, rising from a chair, climbing stairs, and falls’). It is possible to quantity muscle mass from cross-sectional imaging of psoas muscle, although this is not routinely performed. Currently, modification strategies include physical exercises, resistance and endurance training to increase muscle mass, along with the optimization of nutrition.
Malnutrition
Malnutrition is a state of deficiency or energy imbalance leading to measurable adverse effects on function and/or clinical outcomes. Malnutrition can be identified as a body mass index (BMI) of less than 18.5 kg/m 2. . Malnutrition can be screened using the Malnutrition Universal Screening Tool (MUST) which gives points for low BMI (<18.5 kg/m 2. , 18.5–20 kg/m 2. , >20 kg/m 2. ), unplanned weight loss in the last 3 months (<5%, 5–10%, >10%) and if there is an acute illness or 5 days with no nutritional intake to stratify patients as low, medium or high risk. We know that in vascular patients identified preoperatively as medium or high risk for malnutrition there is a strong association with combined measures of postoperative complications.
Once identified targeted nutritional conditioning can be achieved through protein or carbohydrate loading. This approach has been used with success as part of enhanced recovery programmes in patients with colorectal cancer, and likely protects against muscle weakness and wasting, fatigue, and poor wound healing. Of note to vascular patients, dietary interventions may also improve cardiovascular fitness-improving endothelial function and atherosclerosis, management of hypertension and improving glucose homeostasis. Although the evidence base is weaker in vascular surgery, it is not unreasonable to undertake these interventions in this population.
Cognition, delirium and cognitive dysfunction
Patients presenting for vascular surgery may have cognitive dysfunction preoperatively and are at high risk of developing postoperative delirium (POD) and/or postoperative cognitive dysfunction (POCD).
In a cohort study of patients undergoing vascular surgery showed the rate of preoperative cognitive impairment was 11.6% assessed by a mini-mental state examination score of <24, and these patients were associated with significantly worse survival times. Preoperative cognitive dysfunction is a strong risk factor for developing POD – an odds ratio (OR) of 16.4 reported in one study – greater than effects of smoking (OR 7.6), hypertension (OR 7.6) or age (>80 years, OR 7.3).
Attempts should be made to reduce the chance of developing POD or POCD. Close attention should be paid to intraoperative control of blood pressure, depth of anaesthesia, and temperature.
Physical activity
The physical frailty phenotype: low physical activity, slowness, exhaustion, and weakness are associated with an increased risk of adverse perioperative outcomes-many fear increased physical dependence. Optimizing fitness for vascular surgery through interventions such as exercise programmes should be considered early in the perioperative pathway to delay, reverse or prevent the progression of existing symptoms of physical frailty and improve frailty status and the overall outcomes after surgery.
Exercise-based interventions in patients presenting for vascular interventions have demonstrated significant improvement in clinical outcomes, physical performance, and health-related quality of life measures. Moreover, a systematic review of exercise before abdominal aortic aneurysm surgery demonstrated a high compliance rate and significant improvement in the anaerobic threshold. In addition, a supervised exercise programme for 6 weeks before elective abdominal aortic aneurysm surgery was associated with fewer postoperative complications and length of hospital stay although short-term mortality was unaffected. Some have concerns about the safety of exercise with significant vascular pathology. However, in the HIT-AAA study, where patients underwent preoperative high-intensity interval training involving short bursts of vigorous exercise interspersed with periods of low-intensity recovery, there was a very low adverse event rate for exercise. The same team now encourages these patients to undertake community exercise classes.
Anaesthetic care of the frail patient in the operating theatre and recovery
General considerations
The current joint CPOC and British Geriatrics Society guidelines for the care of people living with frailty give recommendations for the care of frail patients in the operating theatre and recovery areas. The following section details some of these recommendations and highlights key evidence and issues.
Before surgery teams should use all the information gathered to provide an individualized intraoperative plan for the patient, focusing on reducing complications. Frailty should be mentioned as part of the World Health Organization (WHO) team brief, and there should be consideration in altering the list order to reduce starvation times for frail patients.
During surgery, there should be senior anaesthetic and surgical input, particularly for emergency cases. There should be consideration of relative or carer presence in the anaesthetic room and recovery areas in patients with cognitive impairment. A urinary catheter should be avoided unless needed due to the risk of hospital-acquired catheter-related infections. There needs to be careful attention to positioning to relieve pressure on vulnerable areas.
Physiology should be meticulously attended to intraoperatively and the calculation of a pre-defined blood pressure target, invasive arterial monitoring, vasopressor infusions and advanced cardiac output monitoring may aid this. Intra-operative hypotension is very common in this group of patients and associated independently with significant morbidity. ,
‘Anticholinergic load’ should be minimized, as this can lead to delirium. These drugs include benzodiazepines, cyclizine, tramadol, and atropine. Glycopyrronium, a quaternary amine, should be used in preference to atropine, a tertiary amine, as it does not cross the blood–brain barrier as easily. Although the high anticholinergic drug burden of regular medication in the elderly population is associated with delirium, the data around perioperative use are limited. Data from the Royal College of Anaesthetists SNAP-3 project, which has prospectively enrolled patients at risk of frailty and delirium in the surgical population, will provide more insight into this area.
General versus regional anaesthesia
In many vascular patients, there is an option of general or regional anaesthesia: carotid endarterectomy, endovascular aortic surgery, and lower limb vascular surgery, including amputation. It is not clear as to whether the use of general anaesthesia or regional anaesthetic technique can significantly impact perioperative outcomes in frail patients, and even less so in vascular cohorts. Cohort studies show similar high rates of delirium (approximately 20%) in patients undergoing common vascular procedures under general, regional and local anaesthesia. The design of randomized controlled trials (RCTs) to evaluate this is difficult due to patient selection and confounders, e.g. propofol sedation during regional anaesthesia.
Specific to vascular surgery is the range of treatment options for abdominal aortic aneurysms. Open surgery exposes a patient to the risks of laparotomy and the physiological effects of aortic cross-clamping. There should be a serious consideration as to the appropriateness of offering open surgery with combined surgical and anaesthetic risk. An anaerobic threshold of more than 11 ml/kg/minute is often quoted as a cut-off for offering open surgery, but some patients lower than this may still be suitable. For those undergoing open repair an epidural plus general technique has better outcomes than general plus systemic analgesia. Alternatively, endovascular techniques (i.e. endovascular aortic aneurysm repair, EVAR) are minimally invasive and may be performed under general anaesthesia, neuraxial blockade, or local anaesthetic infiltration. There is some suggestion from database analysis that regional techniques may be associated with reduced morbidity in patients undergoing EVAR and lower limb revascularisation, but this is not strongly supported by RCTs and may be confounded by issues of cohort studies.
Pharmacokinetic considerations
Ageing and frailty significantly affect drug handling and care should be taken. Alterations in drug dosing are needed. Due to sarcopenia and possibly a higher percent of adipose tissue, lipophilic drugs will have a larger volume of distribution with a potentially longer duration of action, while hydrophilic drugs will have a higher peak plasma concentration. Reduced hepatic blood flow and activity of the cytochrome P450 system may reduce clearance by phase 1 and phase 2 reactions. Frail patients often have reduced renal mass, the speed of renal excretion of drugs, and increases sensitivity to nephrotoxic drugs. A normal estimated glomerular filtration rate may reflect sarcopenia with low creatinine production and should be interpreted with caution.
Anaesthetic induction drug dosing should be modified-propofol can lead to significant hypotension and even cardiac arrest. Due to a smaller initial volume of distribution in the Schnider model of target-controlled infusion, a lower bolus dose is given at induction versus the Marsh model and is often preferred in the elderly and frail where total intravenous anaesthesia is being used. Newer models (e.g. Eleveld) take age more into account and may offer superior conditions.
Lessons from NAP7 for the management of older frail vascular surgery patient
The recent publication of the 7th National Audit Project (NAP7) of the Royal College of Anaesthetists focused on perioperative cardiac arrest, but a deep dive of the data has enabled insight into multiple areas, including frailty, vascular surgery and their interaction, as these groups are relatively over-represented in the cardiac arrest database. , , The data show that despite vascular surgery representing only around 2% of the national anaesthetic activity, 8% of all cardiac arrest cases occurred in this group – a rate of 1 in 670 vascular surgical cases, and survival following cardiac arrest was low in this group (<30%). While many (39%) of these cases were emergency open aortic aneurysm repairs, a substantial number occurred during surgery which was considerably less major (lower-limb revascularization, amputation and endovascular procedures). The main report highlights that the risk of induction of anaesthesia is high in these patients, and cites several cases where relatively high-dose propofol with remifenanil, sometimes combined with hypovolaemia, was associated with cardiac arrest. Indeed, main recommendation 2 states that ‘the older and frailer patient’ is a high-risk cardiovascular situation and goes on to say that ‘high-dose or rapidly administered propofol, in combination with remifenanil, should be avoided’.
Conclusion
Frailty is a common and multidimensional syndrome and a significant issue within the vascular surgical population. We have tools to identify and strategies to mitigate risk and provide high-level perioperative care. The joint CPOC-BGS guidelines for managing patients coming for surgery who are living with frailty apply to all surgical patients and form a core set of standards for the care of this vulnerable group of patients.
Acknowledgements
ADK is supported by the NIHR Central London Patient Safety Research Collaboration (CL PSRC), reference number NIHR204297. The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care.
References
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