How does distance walked in 6 minutes relate to re-hospitalization?

How does distance walked in 6 minutes relate to re-hospitalization?

Clinical Problem Solving IKaylea Kirven

Congestive Heart Failure (CHF) in a 79-Year Old Male

Purpose:•To describe the physical therapy –

▫Examination▫Evaluation▫Plan of care▫Outcomes

•To examine research related to my prognostic question – ▫Is 6-minute walk test distance a prognostic

indicator for re-hospitalization in elderly male patients with severe congestive heart failure?

“Mr. C”•79 year old male•Admitted to hospital presenting with:

▫Abdominal pain ▫Shortness of breath▫Dizziness▫Dysphagia▫Weight gain of 23 lbs

•Past Surgical History:▫CABG x 4 (1981)▫Tonsillectomy

“Mr. C”• Comorbidities:

▫Coronary Artery Disease (CAD)▫Hypertension (HTN)▫Diabetes▫Degenerative Joint Disease▫Chronic Kidney Disease▫Chronic Atrial Fibrillation ▫Previous Stroke (CVA)▫Dementia

• Diagnosis:▫Ingested foreign object▫Congestive Heart Failure (CHF)

Diastolic: NYHA Class I Systolic: NYHA Class IV (Ejection Fraction: 25%)

NYHA Classifications: NYHA Grading

Functional Capacity

Class I:Asymptomatic Dysfunction

No limitations Ordinary physical activity does not cause fatigue, dyspnea, or palpitations

Class II:Mild CHF

Slight limitations Ordinary physical activity results in fatigue, dyspnea, & palpitations

Class III:Moderate CHF

Marked limitations Less than normal physical activity results in symptoms

Class IV:Severe CHF

Unable to carry out any physical activity w/o discomfort Symptoms present @ rest

• Prior Level of Function:▫ Ambulation: RW▫ 24 hr. care

• Review of Systems:▫ Bilateral lower leg edema (2+)▫ Breathing discomfort while

supine w/ head of bed down• Elderly Mobility Scale:

▫ 10/20 “Patient is borderline in terms

of safe mobility & independence in ADLs & requires help with some mobility maneuvers.”

Physical Therapy Evaluation:EVAL

CRITERIAFINDINGS

AROM WFL Shoulder flexion Hip abduction

PROM

MMT Generalized WeaknessDecreased tolerance for activity

Balance:Sitting Static Balance GoodSitting Dynamic Balance Not Tested *Standing Static Balance Fair– with Rolling WalkerStanding Balance with Gait

Fair – with Rolling Walker + CGA

Bed Mobility:Rolling L/R Modified Independence

(HOB raised + Rail utilization)

PT Initial Evaluation: Continued

HOB: Head of BedCGA: Contact Guard Assistance

* Should have been performed

Impairments: Functional Limitations:

•Edema (2+)•Pain (2/10)•Decreased ROM Right > Left•Decreased

Strength•Decreased

Endurance

•Decreased independence

with transfers & ambulation

Disabilities: •Decreased

independence with ADLs

Treatment:Day 1 Day 2 Day 3

Pain (NRPS) 3/10 2/10 1/10Therapeutic Exercises in Sitting(1 set of 10 reps)

- Charleston- Toe Taps- Heel Taps- Seated Marches- Long Arc Quads

SAME SAME

TransfersSit <-> StandWith Rolling Walker

Minimal Assistance x 2

+time & verbal cues

Minimal Assistance x 2

+ verbal cues

Contact Guard Assistance x 1

+ verbal cues

Ambulation 125 ft.(~38 meters)+ RW, CGA, Verbal Cues

Balance Losses: 2

300 ft.(~91 meters)+ RW, CGA, Verbal Cues

Balance Losses: 2

657 ft.(~200 meters)Reached 6 min. of continuous walking + RW, CGA+ 4 Breaks

RW: Rolling Walker LOBs: Loss of BalancesDay 1 Day 2 Day 30

100

200

300

400

500

600

700

Ambulation Distance D

ista

nce

(ft.

)

Patient-Centered Goals: Within 7 days, the patient will…

▫Supine to sit with modified independence ▫Transfer from bed to chair with minimal

assistance + contact guard assistance while holding onto rolling walker

▫Sit to stand with minimal assistance + contact guard assistance

▫Ambulate with contact guard assistance + rolling walker 750 ft. (~228 meters)

PT to see patient 4 x/week

• Treatment Outcomes:▫ Improving & progressing towards goals

• Prognosis:▫Good – Expected to return to previous level of function

Factors Influencing Rehabilitation Potential:1. Medical Condition (-)2. Safety Awareness (-)3. Age (-)4. Comorbidities (-)5. Mental Status (-)6. 24 hr. care @ home (+)7. Supportive Wife (+)

Discharge Site: Home Health Since lives in a 24 hr. care facility

Clinical Question: Is 6-minute walk test distance a

prognostic indicator for re-hospitalization in elderly male patients with severe congestive heart failure?

• Important to consider disease severity & hemodynamic status in CHF patients

• Help identify which CHF patients will likely require intensive therapy?

Promote more effective use of therapies Help optimize treatment in the CHF population

CHF Statistics:•Heart failure is the leading cause of

hospitalization among adults > 65 years old

▫Annually: > 1 million patients are hospitalized for heart

failure [Medicare Expenditure = $17 billion]

▫Within 6 Months of Discharge: > 50% of patients are readmitted to hospital

Prediction of Mortality and Morbidity With a 6-Minute Walk Test in Patients With Left Ventricular DysfunctionJournal of the American Medical Association, 1993Bittner et al.

Article 1:

Bittner et al. •Purpose:

▫To study the potential usefulness of the 6-MWT as a prognostic indicator in patients with left ventricular dysfunction

•Methods: Prospective Cohort Study▫898 patients enrolled in the Studies of Left

Ventricular Dysfunction (SOLVD) Registry Ejection Fraction < 0.45 (45%) &/or

radiological evidence of CHF Ischemic Cause or Hypertensive Cause

▫6-MWT performed at baseline▫Follow-up Period: 242 days

Information provided by 895/898 patients

Walkers:N = 833/898 Substudy Patients Age 60 + 12Sex (%) 78% males / 22% femalesEjection Fraction (%) 37 + 14NYHA I (%) 35%NYHA II (%) 47%NYHA III (%) 14%NYHA IV (%) 1%

Bittner et al.

* Note: Most participants were in LOWER NYHA classifications

• Levels:▫Level 1: < 30o meters▫Level 2: 30o – 374.9 meters▫Level 3: 375 – 449.9 meters▫Level 4: > 450 meters

Bittner et al.

While distance was consistent with functional status at the extremes of the NYHA classification system, this graph demonstrates a substantial range in the broad class of mild impairment (NYHA Class II)

80%:Level 1 & Level 2

Bittner et al. Note: Hospitalization for any reason & hospitalization for CHF INCREASED significantly as distance walked decreased

Performance Level 1:

MORE total hospitalizations

MORE hospitalizations for CHF

Prognostic Usefulness of the Six-Minute Walk in Patients With Advanced Congestive Heart Failure Secondary to Ischemic or Nonischemic CardiomyopathyAmerican Journal of Cardiology, 2001Shah et al.

Article 2:

Shah et al. •Purpose:

▫To analyze the ability of the 6-minute walk test to predict death & hospitalization in patients with NYHA Class III or IV CHF

•Methods:▫471 patients (initially) 440 patients

NYHA Class III or IV Ejection Fraction <25%

▫6-MWT protocol was followed Performed at baseline

▫Follow-up Period: @ 52 weeks

Shah et al.

•Results: How Evaluated? ▫Cox Proportional-Hazards Model

Provides an estimate of the hazard ratio & its confidence interval

Hazard Ratios: The chance of events of a hazard occurring at a group relative to the other

Provide confidence in the reliability of the trial data

6-Minute Walk Test Baseline Distance:

Shah et al.

Baseline 6-MWT Distance N = 365Median: 218 meters

Unable to participate in 6-MWT

N = 75

Default Score: 0 meters (Too ill to walk)

NYHA HR SBP DBP

Cox Proportional-Hazards Model: Distance covered on the baseline test significantly predicted re-hospitalization

Shah et al.

HR 95% CI Chi Square p-value Heart failure patients who increase their walking

distance by 100 meters are 0.15 times less likely to be re-admitted to the hospital (or have a 15% lower risk of re-hospitalization)

0.85/100 m increase

+100 meters +150 meters+200 meters

Relative Risk Reduction: 1 – (HR)- Δ distance

17.6% 27.6% 38.4%

365 Baseline Walkers:

•217/365 hospitalized (60%)

•252/365 combined endpoint (69%)

Shah et al.

Limitations: Bittner et al.

Shah et al. & Bittner et al.• 6-MWT’s performed by a variety of staff members

▫ Reproducibility NOT formally assessed• Patients only assessed once (at baseline)• Small percentage of women

▫ May affect generalizability to both genders • Sub-max Test

▫ Patients DO NOT achieve a peak O2 consumption▫ Hard to compare to maximal exercise testing

• Assistive devices utilized? • What were the participants doing between baseline

testing & follow-up?

• Small sample size among NYHA Class III/IV

Conclusions:Bittner et al. Shah et al.• 6-MWT distance strongly

& independently predictshospitalization rates among NYHA Class I & II CHF patients

• Hospitalization during follow-up was lower▫Fewer severe heart

failure patients EF of 0.45 or less

• Baseline distance walked significantly predicts hospitalization in patients with advanced CHF

• Higher hospitalization rate during follow-up▫Participants had Severe

CHF EF of 0.25 or less

Baseline distancewalked is inversely

related to NYHA Class

How Does This Research Relate to My Patient?

• Article 2 (Shah et al.) relates better to my patient▫ Mr. C met all inclusion criteria

NYHA Class III/IV Ejection Fraction < 25%

• Mr. C walked 200 meters (657 ft.) in 6 minutes▫ First Study: Performance Level 1 (< 300 meters)▫ Second Study: Shy of Median Distance Walked (218

meters)

= His distance walked IS a prognostic indicator for his risk of re-hospitalization

(Actually re-admitted 3 months after I saw him)

In the Future:

1. Do changes in test performance over a 1-month period add further prognostic information? If so,

what change from baseline is clinically significant for a better prognosis?

2. Utilize the 6-MWT to develop/monitor rehabilitation & progression

3. If a patient is too ill to walk, what else can be used to determine exercise capacity?

Conclusion:•Simple, non-invasive method to:

▫Risk-stratify patients with CHF

•Objective measure to:▫Guide clinical judgment & management of

CHF patients

•Safer alternative to cardiopulmonary exercise testing ▫Most CHF patients are unable to perform a

maximal symptom-limited exercise test▫Correlates better with daily activity effort

References:• Bittner V, Weiner DH, Yusuf S, Rogers WJ, McIntyre KM, Bangdiwala SI,

et al. Prediction of mortality and morbidity with a 6-minute walk test in patients with left ventricular dysfunction. SOLVD Investigators. Jama. 1993;270(14):1702-7.

 • Pollentier B, Irons SL, Benedetto CM, Dibenedetto AM, Loton D, Seyler

RD, et al. Examination of the six minute walk test to determine functional capacity in people with chronic heart failure: a systematic review. Cardiopulmonary physical therapy journal. 2010;21(1):13-21.

• Shah MR, Hasselblad V, Gheorghiade M, Adams KF, Jr., Swedberg K, Califf RM, et al. Prognostic usefulness of the six-minute walk in patients with advanced congestive heart failure secondary to ischemic or nonischemic cardiomyopathy. The American journal of cardiology. 2001;88(9):987-93.

Questions?