Changes in absolute coronary flow and microvascular resistance during exercise in patients with ANOCA
Authors' conclusion
Saline-induced hyperaemia provided a valid surrogate for exercise physiology independently of the absolute level of CFR and MRR, although exercise provided more granularity to evaluate adaptation among participants with exercise-related CMD.
Study context
- Population
- Participants with angina with non-obstructive coronary artery disease (ANOCA)
- Participants
- 30 participants
- Comparison
- Exercise-derived vs saline-derived coronary flow reserve (CFR) and microvascular resistance reserve (MRR); Coronary microvascular dysfunction (CMD) vs normal CFRsaline
- CMDn = 16
- Normal CFRsalinen = 14reference
- Outcome
- Q and Rμ adaptation during exercise; correlation between saline- and exercise-derived CFR and MRR (LAD, continuous thermodilution)
Methodological detailsSaline infusion 10 mL/min (rest), 20 mL/min (hyperaemia), 10 mL/min during supine cycling; workload +30 watts every two minutes
- Saline infusion 10 mL/min (rest), 20 mL/min (hyperaemia), 10 mL/min during supine cycling; workload +30 watts every two minutes
Main finding
As reported in the abstract
Exercise adaptation per 30 watts and saline vs exercise agreement
| Group | Value | Rμ decrease |
|---|---|---|
| CMD | 7 (IQR 30.5–103.0) mL/min/30 watts | 109 {IQR 32-286} WU/30 watts |
| Normal CFRsaline | 21 (IQR 5.8–45.0) mL/min/30 watts | 202 [IQR 102-379] WU/30 watts |
Value
CMD7 (IQR 30.5–103.0) mL/min/30 watts
Normal CFRsaline21 (IQR 5.8–45.0) mL/min/30 watts
Rμ decrease
CMD109 {IQR 32-286} WU/30 watts
Normal CFRsaline202 [IQR 102-379] WU/30 watts
- CMD vs Normal CFRsaline: P = 0.01 — increase in Q
- CMD vs Normal CFRsaline: P < 0.01 — decrease in Rμ
- CMD (CFRsaline-defined)
- 53.3% (16/30)
- CFRsaline (overall)
- 2.70±0.90
- CFRexercise (overall)
- 2.85±1.54
- Agreement classification
- 83.3%
- CFR correlation saline vs exercise
- r=0.73; p<0.0001
- MRR correlation saline vs exercise
- r=0.76; p<0.0001
Further findings
- Impaired CFRexercise <2.5 at peak exercise among normal CFRsaline
- 28.7% · 4
Original publication
Changes in absolute coronary flow and microvascular resistance during exercise in patients with ANOCA. EuroIntervention. Published 19 August 2024. doi:10.
Summarised from the published abstract; every number is checked against it