Coronary flow reserve in LAD improves notably after valve replacement in aortic stenosis patients: Study

The study found that coronary flow reserve in the left anterior descending artery (LAD) increased significantly at follow-up. However, there was no change in global hyperaemic flow and minimal microvascular resistance. Thus, a reduction in resting flow was the cause of CFR improvement. CFR improvement was associated with decreased left ventricular mass (LVM) and stroke work (LVSW).

Muhammad Sabbah, Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark, and colleagues conducted the study to achieve the following objectives: 1) investigate whether CFR in the left anterior descending artery would improve after valve replacement and if the changes in hyperaemic coronary flow (QLAD) and minimal microvascular resistance (Rµ,LAD); and 2) examine the relationship between changes in CFR and changes in left ventricular mass and stroke work.

The researchers measured the following before and six months after aortic valve replacement: - intracoronary bolus thermodilution-derived CFR and continuous thermodilution-derived QLAD and Rµ,LAD. Left ventricular anatomy and function were quantified for calculating LVM and LVSW using cardiac magnetic resonance imaging.

The study led to the following findings:

• The study included thirty-four patients (17 patients had transcatheter aortic valve implantation; 14 had surgical valve replacement with a bioprosthesis and 3 with a mechanical prosthesis) who underwent invasive assessment in the LAD.
• CFR increased from 2.5 at baseline to 3.1 at follow-up, despite no significant change in QLAD (230±106 mL/min to 250±101 mL/min) or Rµ,LAD (347 to 287).
• When indexed for LVM, QLAD was 39% higher at follow-up compared with baseline.
• The improvement in CFR was correlated with ∆LVSW, r=-0.39.

"Coronary flow reserve in the left anterior descending artery significantly increased at follow-up although there was no change in global hyperaemic flow and minimal microvascular resistance," the researchers wrote in their conclusion. "Thus, a decrease in resting flow was the cause of CFR improvement. Improvement in CFR was associated with a reduction in LVSW."

Reference:

Sabbah M, Olsen NT, Holmvang L, Tilsted HH, Pedersen F, Joshi FR, Sørensen R, Jabbari R, Arslani K, Sondergaard L, Engstrøm T, Lønborg JT. Long-term changes in coronary physiology after aortic valve replacement. EuroIntervention. 2022 Oct 13:EIJ-D-22-00621. doi: 10.4244/EIJ-D-22-00621. Epub ahead of print. PMID: 36239118.