hypothetical on chronic occlusion

[roybatty]

      is it possible for there to actually be a net loss in functional heart cells when opening a chronically occluded artery even though there appears to be an increase in blood flow on imaging? meaning if there is decreased flow on the capillary/cellular level to cells that were being fed by collaterals that recede after intervention and there is increased flow to previously cut off cells that are no longer functional b/c they have been cut off too long can this result in no actual gain in function or even a net loss?

[roybatty]

thanks for reply. read something about hibernating cells that have been cut off too long and are no longer viable. they're not necrotic per se as in MI but non functional. don't know if that is right or possible its obviously very complex. I am solely interested in knowing if previously stated scenario is possible and drs simply don't want to acknowledge it especially given that imaging cannot see the smallest vessels and thus cant have an accurate picture of what is actually going on. what happens to cells being fed by collateral capillaries when they recede after revascularization? and why is restored blood flow to cells that may not even function any benefit? who knows.

[ed34]

Good question and the answer is not straightforward, but it never is lol. Firstly, you will generally have a better feed from native arteries than you would from collaterals unless you open particularly large ones and many. If you imagine that only around 40-50% of a native artery is sufficient to supply heart muscle when it's working at full capacity, then you could assume that the native artery is going to easily be the best option. It is likely that when blood flow is suddenly restored in a native artery when it has been totally occluded, the cells being fed may suffer temporary damage. This is why is some types of surgery where blood flow is restored, the area is cooled to slow the metabolism of the cells. Damage from what I've read can last up to 3 months. If images show no necrotic tissue, which is obviously never going to reverse, then of course things should improve over the months. Now another big problem is stents in many patients. During the angiogram the results look great on the monitor but they can form blockages pretty damn quick from scar tissue, and I'm speaking of weeks, not years. So in many cases a patient doesn't feel any benefit or feels worse because of this. Lastly, there is the unseen. An artery can look fantastic on the monitor but in reality the blood flow can be shockingly poor. I had an artery which was fully open and it was full of blood. The Cardiologist couldn't understand why I had such bad angina so we decided to use Fractional Flow Rate. This tiny sensor on the catheter reads the blood pressure around it. So, you place the tip at the top of the artery for the base reading which will be around 0.8 and then slowly lower it down the artery watching the reading. Halfway down mine suddenly dropped to 0.4 and so there was invisible endothelium damage causing turbulence. He put one stent in which fixed a few more MM, then it dropped to 0.4 again below the stent. A second stent was inserted and then I had 0.8 to 0.7 from top to bottom which is pretty damn good. My angina vanished. The problem with imaging is the blood flow or pressure isn't actually measured. If an artery looks full, it's taken everything is fine. Even nuclear scans show the amount of blood in tissue, but not how quick it can get there. Tricky business as you can see. I hope this helps