‘Frailty Meter’ May Aid Treatment Decisions in Chronic Limb-Threatening Ischemia

A wrist-worn device may be an option for measuring physical frailty in ambulatory and nonambulatory patients with chronic limb-threatening ischemia (CLTI) scheduled to undergo peripheral revascularization. Researchers who tested the device say it provides an alternative to walking assessments, which pose difficulties for patients with foot ulcers and tissue loss.

“Not being able to walk doesn't mean that that individual is frail, so we wanted to develop a better method to quantify frailty for people who are either limited in walking or for whom it may not be safe to walk,” said Bijan Najafi, PhD (Baylor College of Medicine, Houston, TX).

The frailty meter that he and his colleagues developed consists of a sensor that patients wear on the wrist of their dominant arm while doing 20 seconds of repetitive elbow flexion-extension exercises. The sensor wirelessly transmits data to a tablet, generating a frailty index that classifies them as robust, prefrail, or frail.

“This is something that the patient can easily understand how to do, and they do it while sitting on a surgical chair or on the bed, so it's very safe,” Najafi added. In the study, published this week in JAMA Network Open, the frailty index was approximately 30% higher in patients who developed major adverse cardiovascular and limb events (MACE and MALE) following revascularization compared with those who did not (P = 0.001).

Commenting on the study for TCTMD, Sahil Parikh, MD (NewYork-Presbyterian/Columbia University Irving Medical Center, New York, NY), said frailty assessment of PAD patients deserves to be higher on operators’ radar as an additional tool in multidisciplinary assessment to understand risk, especially since most of these patients have a host of comorbidities. However, no quantitative assessment for frailty in this patient population has yet to be validated, he added.

“We have these conversations with patients and their families all the time about risk-benefit and alternatives. Part of the risk calculation has got to be periprocedural risk, and I think frailty might be a key to better understanding that,” Parikh said.

Adverse Events Higher With Greater Degree of Frailty

For the study, Najafi and colleagues used the frailty meter in 184 consecutive PAD patients scheduled for open bypass surgery or endovascular therapy. Patients had a mean age of 67.8 years and a median Rutherford score of 5. The majority of patients had diabetes (85.3%) and a history of tobacco use (61.3%), and nearly 80% had a foot ulcer.

The wrist-based test was performed 1 week prior to revascularization in either clinic settings or preprocedure holding areas of cath labs. The initial study protocol included a gait test and physical activity questionnaire, but the gait test was dropped after the researchers found that most patients could not perform it.

Patients classified as frail by the meter were older than those who were prefrail or robust, and were more likely to have had a stroke or a fall.

At 30 days, the frail group had a MACE/MALE rate of 31.7% compared with 12.1% the prefrail group and 7.5% in the robust group (P = 0.004). MACE/MALE occurred 2.1 times more frequently among those who were classified as frail versus robust (P = 0.003), and 1.8 times more frequently among those who were frail versus prefrail (P = 0.02).

With the exception of body mass index, no demographic factors were significantly different between the patients who developed MACE/MALE and those who did not. There also was no difference between the groups in rates of common PAD risk factors such as history of foot ulcer, diabetes, hypertension, cardiovascular disease, stroke, or history of tobacco use.

Of the four deaths that occurred, three were patients classified as frail. Similarly, among nine cases of limb loss, five were in patients classified as frail.

The Eyeball Test and Beyond

For now, Parikh said the study suggests that results of a frailty meter could be a useful surrogate measure for overall frailty in CTLI patients, but more work is needed.

We can't manage what we can't measure. Bijan Najafi

“Many of these patients don't pass the ‘eyeball test’ and so consequently, you know that they're frail,” he said. Where a frailty meter like the one in the study might be useful, he added, is in patients who actually are frail but don't appear to be on initial consult. The information on frailty status could help clinicians decide that a patient may be better served by a less-invasive approach, or in some cases, no treatment at all.

Najafi and colleagues say the frailty meter also may improve the ability of clinicians to distinguish whether patients considered robust can tolerate higher-risk interventions. Of the robust group in the study who underwent open surgery, for example, only one developed a nonfatal MACE and one developed a MALE that did not lead to limb loss.

“I really believe that we can't manage what we can't measure,” Najafi observed. He added that his group plans to test the frailty meter in patients undergoing various types of surgery to understand more about its value as a predictive tool.