6 min Walking Test: η σημασία του στην κλινική πράξη Καρακώστας Γεώργιος

Transcription

1 6 min Walking Test: η σημασία του στην κλινική πράξη Καρακώστας Γεώργιος Διευθυντής Καρδιολογικής Κλινικής, Γ.Ν. Κιλκίς

2 Definition The 6 minute walking test (6MWT) is a sub-maximal exercise test used to evaluate the functional capacity in patients with cardiovascular and pulmonary diseases.

3 Background The 6MWT was first described by Balke in 1963, mostly to evaluate the exercise capacity in healthy populations. For years it was used to evaluate patients with chronic respiratory diseases. Guyatt in 1985 and Lipkin in 1986 reported that the 6MWT can identify the most compromised patients suffering from heart failure. Bittner in 1993 reported that the distance walked during the 6MWT is a strong and independent predictor of mortality and morbidity in patients with left ventricular dysfunction.

4 Indications Evaluation of functional capacity Chronic obstructive pulmonary disease Heart failure Cystic fibrosis Peripheral vascular disease Older subjects Evaluation of effects of therapeutic interventions Chronic obstructive pulmonary disease Heart failure Lung resection Lung volume reduction surgery Pulmonary rehabilitation Pulmonary hypertension Prognostic stratification Heart failure Chronic obstructive pulmonary disease Primary pulmonary hypertension

5 Contraindications for walking tests (1) Absolute Acute myocardial myocardial infarction (3-5 days) Unstable Angina Exercise induced uncontrolled arrythmias Active endocarditis, Acute myocarditis or pericarditis Uncontrolled heart failure and pulmonary oedema Acute pulmonary embolus Thrombosis of lower extremeties Suspected dissecting aneurysm Acute respiratory failure Acute non cardiopulmonary disorder that may affect exercise performance or be aggravated by exercise (i.e. infection, renal failure, thyrotoxicosis) Mental impairment leading to inability to cooparate

6 Contraindications for walking tests (2) Relative Resting heart rate > 120 bpm Systolic blood pressure > 180 mmhg Diastolic blood pressure > 100 mmhg Left main coronary stenosis or its equivalent Severe aortic stenosis Tachyarrhythmias or Bradyarrhythmias Advanced pregnancy Severe orthopaedic impairment that prevents walking ERS/ATS (2014)

7 Indentifying a space for the 6MWT A 30 meters long corridor, straight, with no obstacles with a level floor. The space should be quiet enough for the participant to clearly hear your instructions. Any clock or timers should not be visible to the participant. A chair should be available for the participant to test during or after the test. There should be easy access to a telephone and appropriate equipment in case of emergency. The person administrating the test is not necessarily a physician, but he should be trained in basic life support.

8 Required Equipment Two cones to mark the turning points at the either end Stopwatch or countdown timer Measuring tape Pen and paper

9 Before the test The participant should wear comfortable clothing and appropriate footwear. He should continue with his normal medical treatment. If he usually walks with an aid, he should use it during the test. If he usually uses a GTN spray, chronic oxygen or any other inhaler, he should have them with him and use them during the test if necessary.

10 Instructions The text approved by the ATS is the following: The object of this test is to walk as far as possible for 6 minutes. You will walk back and forth in this hallway. Six minutes is a long time to walk, so you will be exerting yourself. You will probably get out of breath or become exhausted. You are permitted to slow down, to stop, and to rest as necessary. You may lean against the wall while resting, but resume walking as soon as you are able. You will be walking back and forth around the cones. You should pivot briskly around the cones and continue back the other way without hesitation. Now I m going to show you. Please watch the way I turn without hesitation. Remember that the object is to walk AS FAR AS POSSIBLE for 6 minutes, but don t run or jog. Start now, or whenever you are ready. ATS 2002

11 Performing the 6MWT Set the timer to 6 minutes. Demonstrate by walking one lap yourself. Start the timer as soon as the participant starts walking Record the number of laps. Record the additional distance walked from the final partial lap. Calculate the total distance.

12 Reasons for immediate stopping Chest pain Intolerable dyspnea Leg cramps Staggering Diaphoresis Pale or ashen appearance ATS 2002

13 Encouragement Encouragement significantly increases the distance walked. Participants are told when 2, 4, and 6 minutes have elapsed. Words like keep up the good work or you re doing fine are provided with even voice at 1 minute intervals.

14 Can Med Assoc J ; 132(8):

15 Reproducibility The degree of reproducibility of a diagnostic or prognostic indicator is one of the factors that can determine its use in clinical practice. CLINICS 2008;63(2):201-6

16 The Borg Scale The Borg Scale is a frequently used quantitative measure of perceived exertion during physical activity. The participant is asked to grade his level of shortness of breath and of fatigue. Borg G. Borg s Perceived Exertion and Pan Scales. Champaign, IL: Human Kinetics, 1998.

17 Advantages of the method Easy to administer Easy to repeat Does not require expensive equipment Does not require advanced training for technicians Has a good correlation with objective measures of effort tolerance, such as oxygen uptake at the peak of exercise Well tolerated because it is similar to the activities of daily living

18 Limitations of the method Does not determine peak oxygen uptake Does not provide specific information on the function of each of the different organs and systems involved in exercise Does not diagnose the cause of dyspnea on exertion Does not evaluate the causes or mechanisms of exercise limitation Results can be affected by a number of factors ATS 2002

19 6MWT sources of Variability (1) Factors reducing the 6MWT : Shorter height Older age Higher body weight Female sex Impaired cognition A shorter corridor Pulmonary disease Cardiovascular disease Musculoskeletal disorders

20 6MWT sources of Variability (2) Factors increasing the 6MWT : Taller height Male sex Encouragement A patient who has previously performed the test Medication for a disabling disease taken just before the test Oxygen supplementation in patients with exerciseinduced hypoxemia

21 Normal values AM J RESPIR CRIT CARE MED 1998;158:

22 6MWT Evaluation of functional capacity Evaluation of effects of therapeutic interventions Prognostic stratification

23 Correlation of 6MWT and NYHA Functional class in PPH Am J Respir Crit Care Med. 2000;161(2,pt 1):

24 Variation in distance walked during the 6MWT at baseline, after three weeks of physical training and after three weeks of activity restriction in a group of patients with stable heart failure. Am Heart J 1997;133:

25 Change in 6MWT distance with common treatments in COPD from randomized controlled trials ICS, inhaled corticosteroids; LABA, long-acting beta agonist; LVRS, lung volume reduction surgery; PRehab, Pulmonary Rehabilitation; SABA, short-acting beta agonist. *P < 0.05 versus control. Internal Medicine Journal 2009;39:

26 Change in 6MWT distance with common treatments in heart failure from randomized controlled trials BB, beta-adrenergic blockers; CPAP, continuous positive airway pressure; CRT, cardiac resynchronisationtherapy *P < 0.05 versus control Internal Medicine Journal 2009;39:

27 Effects of therapeutic interventions on 6MWT o The dashed line shows the variations of distance walked during 6MWT observed in patients with stable heart failure in whom drug dosages were unchanged in short-term. o The continuous line shows the behavior of distance walked in heart failure patients in whom dosages of diuretics and vasodilators have been gradually increased as tolerated. Am J Cardiol 1998;81:

28 The PAVE trial prospectively compared chronic biventricular pacing to right ventricular pacing in patients undergoing ablation of the AV node for management ofatrial fibrillation with rapid ventricular rates. The results are most positive in those with low EFs. There is very little difference in those with preserved LV function. J Cardiovasc Electrophysiol ;16:1160-5

29 REVATIO: SUPER- 1 6-Minute Walk Distance Galie N, Ghofrani HA, Torbicki A, et al. N Engl J Med 2005; 353:

30 Change in 6MWD (m) TADALAFIL: PHIRST 6-Minute Walk Distance Placebo Tadalafil 2.5 mg Tadalafil 10 mg Tadalafil 20 mg Tadalafil 40 mg p<0.001 p< p< Weeks Galiè N et al. Circulation 2009;119:

31 RIOCIGUAT: PATENT-1 6-Minute Walk Distance +36 m Ghofrani HA et al. N Engl J Med 2013;369:

32 Placebo-corrected 6MWD (metres) VOLIBRIS: ARIES 1&2 6-Minute Walk Distance p< p< mg 10 mg Συνδυασμένη δόση ambrisentan p vs placebo Galiè N et al Circulation 2008;117:

33 Pulido T, et al. N Engl J Med 2013; 369: Pulido T, et al. N Engl J Med 2013; 369: MACITENTAN: SERAPHIN 6-Minute Walk Distance Macitentan 3 mg Macitentan 10 mg Placebo-corrected change in 6MWD from baseline at Month 6 Baseline-adjusted mean Overall FC I/II FC III/IV 18 m [-2, 37] 6 m [-19, 32] 33 m [2, 63] p = 0.04 p = 0.58 p = m [4, 42] 12 m [-8, 33] 37 m [5, 69] p < 0.01 p = 0.18 p < 0.01 [Confidence limits 97.5%]

34 Median change from baseline (m) AMBRISENTAN&TADALAFIL: AMBITION STUDY 6MWD: change from baseline to week 24 Primary Analysis Set Median change in 6MWD (m) from baseline Week 24 Combination: +49.0m Pooled mono: +23.8m (p<0.001) Ambrisentan mono: +27.0m (p<0.001) Tadalafil mono: +22.7m (p=0.003) Time (weeks) N. Galiè, et al. N Engl J Med 2015;373: Vertical bars represent 95% CIs. Stratified Wilcoxon Rank Sum analysis. Worst rank scores were used for missing data following death or adjudicated hospitalisation; otherwise, LOCF imputation was used.

35 Prognostic value of 6MWT Kaplan-Meier curve showing survival based on 6MWT distance in older patients with CHF. European Heart Journal 2007;28:

36 Risk of death at 24 months based on 6MWT in patients with > mild LVSD. European Heart Journal 2007;28:

37 Am J Respir Crit Care Med. 2000;161(2,pt 1):

38 Patients with PAH Kaplan-Meier survival estimates based on absolute 6MWT distance thresholds at 165 m and 440 m, and all possible 6MWD thresholds. J Heart Lung Transplant 2015;34:

39 The 6MWT distance & resting SO2 predict outcome in adult patients with Eisenmenger syndrome Predicted survival at 3-years International Journal of Cardiology 2013;168:

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