Pitfalls in Coronary Physiological Testing: Beware of the “Accordion” Effect With Wire-Based Physiological Testing!

Physiological testing pre-percutaneous coronary intervention (PCI) with either fractional flow reserve or instantaneous flow reserve has been shown to improve long-term outcomes in patients with stable ischemic heart disease compared with angiography alone.1Tonino P.A.L. De Bruyne B. Pijls N.H. et al.Fractional flow reserve versus angiography for guiding percutaneous coronary intervention.N Engl J Med. 2009; 360: 213-224https://doi.org/10.1056/NEJMoa0807611Crossref PubMed Scopus (3370) Google Scholar,2Götberg M. Berntorp K. Rylance R. et al.5-year outcomes of PCI guided by measurement of instantaneous wave-free ratio versus fractional flow reserve.J Am Coll Cardiol. 2022; 79: 965-974https://doi.org/10.1016/j.jacc.2021.12.030Crossref PubMed Scopus (32) Google Scholar Physiological testing requires meticulous preparation and recognition of pitfalls in the interpretation of an "ischemic" value. One such pitfall is the "accordion" or "concertina" effect.3Muller O. Hamilos M. Ntalianis A. Sarno G. De Bruyne B. Images in cardiovascular medicine. The accordion phenomenon: lesson from a movie.Circulation. 2008; 118: e677-e678https://doi.org/10.1161/CIRCULATIONAHA.108.791210Crossref PubMed Scopus (19) Google Scholar In a normally curvaceous coronary artery, the pressure wire may straighten the vessel producing "pseudo-lesions," which may ultimately decrease flow, producing an ischemic value. Performing PCI in this circumstance would be inappropriate. We present an "ischemic" instantaneous flow reserve due to the "accordion" or "concertina" effect where the "lesion" sites were shown by intravascular ultrasound to be without or with minimal plaque and a widely patent lumen (Figure 1, Supplemental Videos 1 and 2). Interventionists should be aware of this phenomenon and perform a pullback routinely to ensure the appropriate use of PCI.Figure 1Case example of the "accordion" effect. (A) Baseline left coronary artery in the right anterior oblique projection. There is a 50% ostial left anterior descending artery (LAD) lesion that is not well seen in this projection. Please note that the LAD has multiple curves in its course to the apex. (B) The LAD becomes straightened after the passage of a pressure wire for physiological testing. (C) With the pressure transducer in the distal LAD, the spot instantaneous flow reserve value was in the ischemic range at 0.85. (D) Pressure wire pullback showed a gradual increase consistent with primarily "diffuse" disease. (E) Coregistration of angiography and pressure (SyncVision, Philips Healthcare) shows 2 sites with a pressure step-up of 0.04 (each dot represents a pressure change of 0.01). Please note that these 2 sites of pressure change correspond to curves in the vessel in the absence of the pressure wire. (F) Intravascular ultrasound interrogation of the distal site with the pressure step-up on pullback showed no plaque. (G) Intravascular ultrasound interrogation of the more proximal site with the pressure step-up on pullback showed minimal plaque. Refer to Supplemental Videos for further review.View Large Image Figure ViewerDownload Hi-res image Download (PPT) The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. This work was not supported by funding agencies in the public, commercial, or not-for-profit sectors.