Value of CPET in clinical follow-up

Gökhan M. Mutlu, M.D.Pulmonary and Critical Care Medicine

Northwestern University Feinberg School of Medicine

Turkish Thoracic Society MeetingAntalya, Turkey

April 2008

Financial Disclosure: Nothing to disclose

CPET: indications

• Evaluation of exercise tolerance• Evaluation of undiagnosed exercise intolerance

• Evaluation of patients with CV disease• Evaluation of patients with respiratory diseases/symptoms

• Preoperative evaluation• Exercise evaluation and prescription for pulmonary rehabilitation

• Evaluation of impairment/disability• Evaluation for lung, heart and heart-lung transplantation

ATS/ACCP Statement of CPET AJRCCM 2003

CPET: Clinical follow-up indications

• LV failure– Clinical follow-up– Evaluation for heart or heart-lung transplant

– Monitoring response to treatment

• Pulmonary hypertension– Clinical follow-up– Monitoring response to treatment

• Chronic pulmonary disease– Before and after exercise training program– Before and after LVRS

ATS/ACCP Statement of CPET AJRCCM 2003

CPET: Clinical follow-up indications

• Pulmonary rehabilitation– Before and after pulmonary rehabilitation

•To determine the exercise prescription and to assess clinical response

• Heart and/or lung transplantation– Before and after transplantation

ATS/ACCP Statement of CPET AJRCCM 2003

CPET: Clinical follow-up

Most commonly used parameters for clinical follow-up

• Peak VO2

• AT• VE/VCO2

• O2 pulse• VO2/WR

• AT determination is helpful as an indicator of level of fitness, for exercise prescription and to monitor the effect of physical training

Cardiac diseases: LV failure

VO2

• the “gold standard” measure of aerobic fitness

• Related to the severity of heart failure

• Used to stratify risk, guide management and determine exercise training thresholds

• >18 ml/kg/min- mild impairment, low risk of CV death in CHF patients

• <14 ml/kg/min- indication for heart transplant• <10 ml/kg/min- severe impairment, high risk of CV

death. Poor prognosis at 1 year

Cardiac diseases: LV failure

VO2

1-year survival

>14 ml/kg/min- “too well”- 94%<14 ml/kg/min + accepted for transplant- 48%<14 ml/kg/min + comorbidities- 47%

Costanzo MR, et al. Circulation 1995;92:3595-612

Ingle L, et al. Eur J Heat Failure 2008;10:85-88

Cardiac diseases

VE/VCO2

Cardiac diseases: LV failure

VE/VCO2

• Normal <29• VE/VCO2 is inversely related to peak VO2

• Low VE/VCO2 is independently associated with a worse prognosis

• Cut-off unclear– ≥35 has been suggested as a predictor

Ingle L, et al. Eur J Heat Failure 2008;10:85-88

Cardiac diseases: LV failure

Cardiac diseases: LV failure

AT• A surrogate measure of quality of life in patients

with CHF

• An important marker of outcome

Cardiac diseases: LV failure

6-min walk test (6-MWT)

• A submaximal test of functional capacity

• Simple to perform• Inexpensive• Tolerable as patients are self-paced during exertion

• Reproducible (if well standardized)

Cardiac diseases: LV failure

6-MWT vs CPET (VO2 peak)

• Only a moderate relationship• Useful to determine prognosis in CHF

• 6-MWT <300 m is a simple and useful prognostic marker of subsequent cardiac death in patients – with severe CHF undergoing evaluation for heart

transplantation and – with patients with moderate (NYHA class II-III) systolic

heart failure

Diastolic heart failure

• The role of CPET is less well studied. • CPET provides similar prognostic information. • Cut-off values are different and depend on the

LVEF

• Peak VO2 is less valuable compared to VE/VCO2

• VE/VCO2

– 32.6 (EF>40%), 33.1 (>45%) , 33.3 (>50%)

Guazzi M, et al. J Am Coll Cardiol 2005;46:1883-90

Pulmonary hypertension

CPET vs. 6-MWT

There may not be a correlation between CPET and 6-MWT1.

Oudiz RJ et al. Am J Cardiol 2006;997:123-6

• 178 patients• ETR antagonist vs. placebo

1. Barst RJ, et al. Am J Respir Crit Care Med 2004;169:441-72. Oudiz RJ, et al. Am J Cardiol 2006;997:123-6

Pulmonary hypertension

Oudiz RJ, et al. Am J Cardiol 2006;997:123-6

Better correlation when CPET is compared with weight adjusted 6-MWT and at week 12.

Pulmonary hypertension

American Thoracic Society Guidelines

• CPET is recommended for follow-up of PAH patients

• 6-MWT is complimentary• CPET is more discriminating• More sensitive at detecting small differences in

exercise capacity

ATS Statement. AJRCCM 2002;166:111-7

Exercise rehabilitation

• Exercise therapy has been recommended for all stable patients with CHF

• A systematic review of 81 studies and Meta-analysis of 9 randomized trials.

• Exercise training programsare safedecrease mortality from CHFhas been shown to improve exercise

toleranceSmart N, et al. Am J Med 2004; 116:693-706Piepoli MF, et al. BMJ 2004;328:189

Exercise rehabilitation

VO2 peak • a more accurate marker of exercise tolerance than

heart rate• preferable to measure gas exchange during

exercise and to prescribe the intensity of the exercise regimen

• Healthy: At rate corresponding to 50-70% of VO2 peak

• For CHF patients with severe dysfunction- 40-50% of VO2 peak

Exercise rehabilitation

The magnitude of improvement in peak VO2 after exercise programs range between 10% and 26% of initial (pre-training) value

Statement on CPET in chronic heart failure due to left ventricular dysfunction Eur J of Cardiovasc Prev and Rehab 2006;13:486-94

Keteyian, S. J. et. al. Ann Intern Med 1996;124:1051-1057

Peak oxygen consumption in patients with compensated heart failure who did not have exercise training (control group, n = 14) and who did have exercise

training (exercise group, n = 15)

Effect of therapy on CPET in CHF

Pharmacologic treatment

AT1RB ACEI BB

VO2 peak ↑ ↑ ↔

VE/VCO2 ↓ ↑ ↓

O2 pulse ↑ ↑ ↑

VO2/WR ↑ ↑ ↔

CPET: Clinical follow-up

What is considered significant?• VO2 peak is generally considered reproducible• In order to avoid under and over-estimation with

absolute values, changes over time should be expressed as a % of baseline capacity

• Variation is influenced by the severity of the condition and interval between tests

• Short-term coefficient 4.1%-6%

CPET: Clinical follow-up

• To improve reproducibility, the tests should be performed at the same time of the day

• Every clinical exercise laboratory should provide short and long-term coefficients of variation of peak and submaximal gas exchange parameters

• Another problem area is the correlation between VO2 peak and the subjective clinical exercise tolerance.– Variations of VO2 peak do not necessarily reflect changes

in symptom status.– Several studies have shown a non-linear relation between

VO2 peak, symptoms and quality of life.