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Standard exercise stress testing attenuates peripheral microvascular function in patients with suspected coronary
Massimo Nardone1, Steven Miner1,2, Mary McCarthy2
1School of Kinesiology and Health Science, York University, 355 Norman Bethune College, Toronto, Ontario, Canada.
Insights
Coronary microvascular dysfunction (CMD) impairs peripheral microvascular function. Acute exercise further reduces this function, diminishing the accuracy of RH-PAT testing in diagnosing CMD.
Area of Science:
- Cardiology
- Vascular Biology
- Diagnostic Testing
Background:
- Coronary microvascular dysfunction (CMD) diagnosis is challenging.
- The impact of exercise on peripheral microvascular function in suspected CMD is not well understood.
- Reactive hyperemia peripheral arterial tonometry (RH-PAT) is a potential diagnostic tool.
Purpose of the Study:
- To investigate the effect of clinical exercise stress testing (GXT) on peripheral microvascular function in patients with suspected CMD.
- To determine if GXT influences the accuracy of RH-PAT measurements for CMD detection.
Main Methods:
- A cross-sectional study of 76 patients with suspected CMD.
- Patients were grouped into 'exercisers' (GXT before RH-PAT) and 'non-exercisers' (GXT after RH-PAT).
- Peripheral microvascular function was assessed using RH-PAT, quantifying the reactive hyperemia index (RHI and LnRHI).
Main Results:
- Patients with CMD showed lower LnRHI compared to those without CMD.
- Exercisers exhibited lower LnRHI than non-exercisers, irrespective of CMD status.
- RH-PAT's ability to predict CMD was significantly reduced in patients who exercised prior to testing.
Conclusions:
- CMD is linked to impaired peripheral microvascular function.
- Acute exercise exacerbates microvascular dysfunction and negatively impacts RH-PAT accuracy.
- RH-PAT assessments for suspected CMD should be performed before exercise.
Background:
The effect of exercise on the microvasculature of patients with suspected coronary microvascular dysfunction (CMD), assessed by reactive hyperemia peripheral arterial tonometry (RH-PAT; EndoPAT), is unknown. The present study aimed to determine if standard clinical exercise stress testing (GXT) affected peripheral microvascular function, as determined by the reactive hyperemia index (RHI and LnRHI), in patients with suspected CMD.
Methods:
In a cross-sectional study, patients (n = 76) were grouped based on whether the GXT was performed; 1) prior to (exercisers; n = 30), or 2) after the vascular assessment (non-exercisers; n = 46). Patients with an adenosine index of microvascular resistance > 25, adenosine coronary flow reserve (CFR) < 2.0, and/or acetylcholine CFR < 1.5 were considered to have CMD (n = 42). RHI and LnRHI quantified finger pulse amplitude hyperemia following 5 min of forearm ischemia.
Results:
LnRHI was lower in patients with CMD compared to patients without CMD, while LnRHI was also lower in exercisers compared to non-exercisers (LnRHI: CMD Non-Exercisers: 0.63 ± 0.25; CMD Exercisers: 0.54 ± 0.19; No CMD Non-Exercisers: 0.85 ± 0.23; No CMD Exercisers: 0.63 ± 0.26; Condition and Exercise Main Effects: Both P < 0.01). In patients who did not exercise prior to the vascular assessment, the receiver operating characteristic curve (ROC) for LnRHI to predict CMD was 0.76 (95% CI: 0.62-0.91; P < 0.01). However, in patients who performed exercise prior to the vascular assessment, the ROC for LnRHI to predict CMD was 0.60 (95% CI: 0.40-0.81; P = 0.34).
Conclusions:
CMD is associated with impaired peripheral microvascular function and preceding acute exercise is associated with further reductions of LnRHI. Further, acute exercise abolished the capacity for RH-PAT to predict the presence of CMD in patients with chest pain and non-obstructive coronary arteries. RH-PAT measurements in patients with suspected CMD should not be conducted after exercise has been performed.
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