Continuous thermodilution-derived microvascular resistance reserve (MRR) strongly correlated with Doppler MRR (r = 0.88; 95% CI 0.72-0.93; P<0.001) for assessing microvascular function.
Observational (n=30)
Does continuous thermodilution-derived MRR correlate with Doppler MRR for assessing coronary microvascular function?
MRR is proposed as a specific, quantitative, and operator-independent metric to quantify coronary microvascular dysfunction, showing strong correlation between thermodilution and Doppler methods.
Effect estimate: r = 0.88 (95% CI 0.72-0.93)
p-value: p=<0.001
The need for a quantitative and operator-independent assessment of coronary microvascular function is increasingly recognized. We propose the theoretical framework of microvascular resistance reserve (MRR) as an index specific for the microvasculature, independent of autoregulation and myocardial mass, and based on operator-independent measurements of absolute values of coronary flow and pressure. In its general form, MRR equals coronary flow reserve (CFR) divided by fractional flow reserve (FFR) corrected for driving pressures. In 30 arteries, pressure, temperature, and flow velocity measurements were obtained simultaneously at baseline (BL), during infusion of saline at 10 mL/min (rest) and 20 mL/min (hyperemia). A strong correlation was found between continuous thermodilution-derived MRR and Doppler MRR (r = 0.88; 95% confidence interval: 0.72-0.93; P < 0.001). MRR was independent from the epicardial resistance, the lower the FFR value, the greater the difference between MRR and CFR. Therefore, MRR is proposed as a specific, quantitative, and operator-independent metric to quantify coronary microvascular dysfunction.
Bruyne et al. (Fri,) conducted a observational in Coronary microvascular dysfunction (n=30). Continuous thermodilution-derived MRR vs. Doppler MRR was evaluated on Correlation between continuous thermodilution-derived MRR and Doppler MRR (r = 0.88, 95% CI 0.72-0.93, p=<0.001). Continuous thermodilution-derived microvascular resistance reserve (MRR) strongly correlated with Doppler MRR (r = 0.88; 95% CI 0.72-0.93; P<0.001) for assessing microvascular function.