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Interesting Case from @GreggWStone which brings up lots of thoughts. (1) iFR/FFR discordance with angiographic finding is well established. Very 'tight' stenoses can be negative (& leads to much head scratching in labs around the world) but PW superior in stable native disease. https://twitter.com/GreggWStone/status/1354092626463612929
(2) iFR/FFR is often negative in the LCx due to hydrostatic pressure differences & the smaller myocardium subtended. Often need very severe stenosis to be positive - and if positive, you can be confident that truly ischaemic. @DrKeeble @MGtberg @drandrewsharp
(3) iFR-FFR discordance is another story. Many in the thread have suggested doing FFR instead. The majority of the time there is match, when there isn't - there is not much clinical difference regardless of the approach taken (stent / defer) based on observational data.
(3b) Rolling the physiological dice again by giving adenosine is always an option; Many do that having gone to trouble of re-wiring with a PW. Regardless of the result - what RCT data are you basing treatment of that lesion on? Specific to LMS bifurcation?
(4) Side branch story is interesting. Do stent struts across an ostium really represent the same biological phenomena as a classical coronary stenosis (in which iFR/FFR were validated with outcomes)? Pinched side branches differ. Is it the carinal angle or plaque shift?
(4b) There is limited data. Mostly it shows FFR can be performed & not outcomes. Both Koo & SJ Park have observational data that most side branches are FFR negative. Naturally it will be biased by side-branches that can be wired with PW technology from 2005-2011 (ie. easy ones).
The number of Ostial LCx in these Cohorts is modest as it represented the type of PCI performed at the time. 11 in the SJ Park study ( https://doi.org/10.1016/j.jcin.2011.10.015).
(4c) If we do defer this ostial LCx, do we expect the natural history to be the same as in deferring stable coronary disease in the mid-LAD or RCA? Or do we think there will be an impact from instent restenosis (even trivial)? Ostial LCx is famously difficult.
(4d). What about the distal vessel and ease of access for future intervention? It would be straight forward to open struts, kiss and Re-POT. The LCx size means you probably won't touch the sides. This may change if there is progressive disease there - possible!
(5). (Finally) What about day-to-day clinical factors that impact on practice? What will you do if the patient has some chest pain a few hours / days later? Are you committing the patient to frequent testing (as done in some places).
Lots of Q? Few True Answers!
Lots of Q? Few True Answers!
