When physiology defies anatomy cardiologists tend to get confused !
Posted May 18 2011 4:45am
Even as we make rapid strides in conquering coronary atherosclerosis by all those fancy gadgets , the fundamental coronary hemodynamic principle is poorly understood . Hence there is no surprise for the “perennial ambiguity” in the indication and effectiveness of coronary revascularization .
Why the hell , reliving a coronary obstruction may not provide the expected hemodynamic benefit or do not prevent future heart attack in many ? One of my patients asked ?
I told him . Wait , do not get excited , we also do not know . . .We are just beginning to understand mysteries of coronary circulation.
It is a well documented fact ( but a debatable ) that lesser the severiity of a lesion more likely it is prone for an acute coronary event .( Vulnerability , shearing stress or is it a simply a statistical mirage !) While the vulnerability aspect is complex , the hemodynamic impact of coronary lesions is relatively better understood. Here is an important documentation from Dr B . K Koo from Seoul , South Korea who has elegantly shown the behavior of fractional flow reserve (FFR ) in various grades of stenosis .This study was done in jailed side branches following PCI.
FFR shows a surprise relationship with severity of coronary stenosis . Even severe lesions showed equal if not more flow reserve ?
and mild lesions might have lost all its reserve.
How is it possible ? Can it be true ?
Yes , it is indeed a fact . God generally keeps a stong link between anatomy and physiology , structure and function . But he adds a rider and keeps a reserve in every human cell meant for emergency back up . FFR is one aspect of this , we have partially discovered . When we fail to understand this we are bound to get confused and make a wrong decision in cath lab.
Simply stated , flow across a coronary artery is much more depedent on the status of microvascualture than the hurdles they face in the epicardial highways !
Link to this original article from JACC .
How to do the FFR procedure ?
Soon to follow . . . If less severe lesions are more dangerous why we are ignoring it in cath lab ?