Improvement in coronary microvascular dysfunction after transcatheter aortic valve implantation leading to positive fractional flow reserve and percutaneous coronary intervention: a case report

The management of coronary artery disease in patients with severe aortic stenosis is controversial, with no consensus on optimal revascularization strategies. The validity of using fractional flow reserve to assess ischaemia in this population is debated. Conflicting results have arisen regarding the impact of transcatheter aortic valve implantation on fractional flow reserve values. We present the case of a patient with severe aortic stenosis and intermediate left anterior descending artery stenosis, in whom the fractional flow reserve and the index of microcirculatory resistance suggested the presence of coronary microvascular dysfunction prior to transcatheter aortic valve implantation. However, after valve replacement, the fractional flow reserve and the index of microcirculatory resistance indicated physiologically significant ischaemia, prompting intervention.

An 82-year-old woman presented with paradoxical low-flow, low-gradient severe aortic stenosis and intermediate left anterior descending artery stenosis. The fractional flow reserve was borderline, and the index of microcirculatory resistance was elevated before transcatheter aortic valve implantation, indicating the presence of coronary microvascular dysfunction. Six months after valve replacement, the fractional flow reserve declined to 0.64 with an improved index of microcirculatory resistance, prompting a successful percutaneous coronary intervention. Subsequent cardiac magnetic resonance imaging revealed reverse remodelling with a reduced left ventricular mass.

This case illustrates that transcatheter aortic valve implantation may unmask coronary ischaemia by restoring microvascular vasodilatory capacity in patients with coronary microvascular dysfunction. It also highlights the importance of reassessing coronary physiology in selected patients following transcatheter aortic valve implantation.