Key result
In asymptomatic patients with exercise-induced ST changes, significant coronary lesions were associated with a flattened DeltaVO2/Deltawork relationship above the anaerobic threshold (7.4 vs 9.4 ml/watt per minute, P<0.01).
Why the study?
Can gas exchange kinetics during cardiopulmonary exercise testing differentiate asymptomatic patients with exercise-induced ST changes who have significant coronary lesions from those who do not?
Cross-Sectional (n=83)
Can gas exchange kinetics during cardiopulmonary exercise testing differentiate asymptomatic patients with exercise-induced ST changes who have significant coronary lesions from those who do not?
Absolute Event Rate: 7.4% vs 9.4%
p-value: p=<0.01
Cardiopulmonary exercise testing can help identify significant epicardial coronary disease in asymptomatic patients with exercise-induced ST changes by revealing flattened DeltaVO2/Deltawork relationships and lower VO2 values.
Flattened DeltaVO2/Deltawork may support CPET differentiation of silent ischaemia; leaves open prospective validation before clinical adoption.
BACKGROUND: Exercise-induced ST changes, suggestive of cardiac ischaemia, are found in asymptomatic patients. METHODS: Gas exchange kinetics were studied during exercise to help to separate patients affected by epicardial coronary disease from those without. Forty-eight patients, without angina symptoms and showing significant changes of ST during exercise, underwent a coronarography and maximal cardiopulmonary exercise test. Thirty-five healthy individuals of matched age and sex underwent a cardiopulmonary exercise test as controls. RESULTS: Patients were grouped according to the presence (group 1, n = 35) or the absence (group 2, n = 13) of significant coronary lesions at angiography. When corrected for predicted oxygen consumption (VO2) at peak exercise and at anaerobic threshold, results showed a low VO2 at peak exercise and anaerobic threshold in group 1 (68 +/- 19 and 84 +/- 17% of predicted, respectively) compared with normal subjects (91 +/- 19 and 96 +/- 24% of predicted VO2) and group 2 patients (86 +/- 17 and 96 +/- 18%). Also the ischaemic threshold, when normalized for predicted workload at peak exercise, occurred earlier in group 1 (67 +/- 22%) than in group 2 (87 +/- 19%). The time-related (Delta)VO2/Deltawork relationship showed a significant flattening above the anaerobic threshold in group 1 (7.4+/-2.2 versus 9.4+/-1.4 ml/watt per minute, P < 0.01), but not in controls or in group 2. Also the DeltaVO2/Deltawork relationship, above the ischaemic threshold, flattened in group 1, but not in group 2. CONCLUSION: The suggestion of major coronary disease in patients with exercise-induced ST changes is given by: (i) a flattening of the DeltaVO2/Deltawork relationship, above both the ischaemic and anaerobic thresholds; and (ii) low VO2 values at anaerobic and ischaemic thresholds.
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Bussotti et al. (2006) conducted a cross-sectional in Exercise-induced silent ischaemia (n=83). Significant coronary lesions at angiography vs. Absence of significant coronary lesions and healthy controls was evaluated on DeltaVO2/Deltawork relationship above the anaerobic threshold (p=<0.01). In asymptomatic patients with exercise-induced ST changes, significant coronary lesions were associated with a flattened DeltaVO2/Deltawork relationship above the anaerobic threshold (7.4 vs 9.4 ml/watt per minute, P<0.01).
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