Preoperative frailty assessments may help predict mortality and functional decline among seniors undergoing cardiac surgical procedures. The results of this systematic review were published online August 23 in the Annals of Internal Medicine.
“Despite various ways of measuring frailty, we found strong evidence that it predicts mortality at 6 months or later after major or minimally invasive procedures,” write Dae Hyun Kim, MD, MPH, ScD, from the Beth Israel Deaconess Medical Center, Boston, Massachusetts, and colleagues. “Some evidence indicated that frailty may predict functional decline, poor quality of life, or lack of symptomatic benefit after minimally invasive procedures.”
Previous studies have demonstrated a link between preoperative frailty and poor 30-day outcomes; however, the findings of the present study provide data on longer-term outcomes.
The researchers identified 25 studies that evaluated the association between frailty and death or functional decline 6 months or more after cardiac procedures in patients 60 years of age or older. Procedures were classified as major (coronary artery bypass grafting or open valve surgery) or minimally invasive (transcatheter aortic valve replacement). Nine frailty instruments were evaluated in the major surgery group, and 13 in the minimally invasive group.
Data from 18,388 patients undergoing major surgery and 5177 undergoing minimally invasive procedures were included. In the major surgery group, the researchers found that, among those studies using single-component frailty instruments, distance on the 6-minute walk test (6MWT), low albumin levels, and activities of daily living (ADLs), dependence was associated with a 2.4- to 3.6-fold increase in the risk for death or major adverse cardiovascular and cerebrovascular events (MACCEs).
Among patients in the minimally invasive group using single-compartment frailty instruments, the researchers found a 1.2- to 3.2-fold increase in mortality among patients with a musculoskeletal or neurologic disorder, those using an assistive device, and those with low 6MWT scores. Use of multicomponent frailty instruments in this group yielded variable results; however, frailty was significantly associated with a 1.9- to 5.6-fold risk for death. Studies using a composite outcome of death and poor functional status found a 2.6- to 2.8-fold risk increase among this group.
Comparing Frailty Instruments
Eight studies directly compared frailty instruments and found that objective measures of lower extremity performance such as the 6MWT or the Timed Up and Go (TUG) test were more predictive than cognitive tests, subjective assessments, or self-reported mobility impairment. The authors also note that overall, multicomponent frailty instruments were more predictive of mortality than single-component instruments.
Overall, the authors note that “[c]urrent evidence best supports mobility assessment as a single-component frailty instrument before cardiac surgical procedures.” These would include tests such as the 6MWT or TUG tests. In the absence of that, asking patients about their ability to climb stairs, wheelchair use, or difficultly walking because of musculoskeletal or neurologic disease can be considered an alternative screening method. The authors note that use of multicomponent frailty tools may also provide more comprehensive risk assessment and caution that merely using subjective assessments of patient frailty should be avoided.
The authors suggest that establishing criteria for using single-component vs multicomponent frailty tools, as well as standardization of the frailty domains that should be evaluated (eg, mobility, nutrition, disability, and cognition), may facilitate adoption of preoperative frailty assessment among clinicians.
In an accompanying editorial, Victoria L. Tang, MD, MAS, and Kenneth Covinsky, MD, MPH, from the University of California, San Francisco, write: “Although frailty in surgical prognostication remains an early area of research, the Kim group’s systematic review significantly advances the field.”
Dr Tang and Dr Covinsky agree that frailty assessment will help predict mortality risk in this population; however, further research evaluating other outcomes such as long-term disability and quality of life is needed.
Once a decision to have surgery is made, “[u]sing a frailty assessment to guide postoperative planning and provide anticipatory guidance would help prepare patients and caregivers by providing the information necessary to plan, prepare, and set appropriate expectations,” write Dr Tang and Dr Covinsky.
The review authors point out that the heterogeneous nature of the literature, lack of validated frailty instruments, and publication bias make it difficult to generalize predicted risk among all patients.
Funding for this study was provided by the National Institute on Aging and National Heart, Lung, and Blood Institute.