Physiology guidance for coronary artery disease in patients with severe aortic stenosis: are we there yet?

Abstract

Full text

Authors' response to the commentary of Minten and Dubois, https://doi.org/10.1093/ehjopen/oeaf052.

We thank Dr. Minten and Dubois for a relevant comment regarding the physiology assessment of coronary artery disease in patients with severe aortic stenosis (AS).^1^ In general, we agree with the issues raised. Due to the impact of severe AS on the haemodynamic and the myocardial structure, these patients have increased coronary flow reserve, increased microvascular resistance, and increased resting flow.^2,3^ After aortic valve replacement, the coronary flow reserve increases, the microvascular resistance decreases, the resting flow decreases, but the hyperaemic absolute flow roughly remains unchanged.^2,3^ Due to these physiological changes, the resting indices for assessing coronary artery disease increase significantly after valve replacement, whereas the fractional flow reserve (FFR) decreases slightly or remains unchanged.^2,4^ It has been demonstrated that resting indices change across the cut-off value of 0.89 in around 40% of the patients compared with 10–20% for FFR using a 0.80 cut-off.^2,4^ However, the negative predictive value for resting indices is close to 100%, whereas the positive predictive value for FFR is close to 90%.^2,4^ Therefore, combining a resting index to exclude and FFR to confirm haemodynamic significant coronary artery disease could be a suggested strategy. However, having said this, the NOTION-3 trial showed that the benefit from revascularization was most pronounced in patients a coronary lesion with diameter stenosis ≥90% in whom FFR was not used to assess the lesion,^5^ in agreement with previous observations that the benefit from revascularization correlates with the severity of ischaemia (FFR value).^6^ It may thus be questioned whether it is indicated to perform revascularization of coronary lesions with FFR value in the border zone in patients with severe AS undergoing TAVI—especially in the light of increased bleeding risk.^5,7^