Health knowledge made personal
Join this community!
› Share page:
Go
Search posts:

What is no reflow ? What is the mechanism of no reflow ?

Posted Nov 18 2008 12:10am

                                            No reflow is the terminology used primarily in cath labs where, even  after a successful opening and stenting  of a coronary artery the coronary blood flow is not  restored to myocardium . The point to be emphazised here is blood do cross  successfully the site of  the obstruction but fails to enter the muscle segment  to which the coronary artery is supplying . So the paradoxical situation of artery  being open but the  myocardium is closed to receive  blood flow  happens . This is termed as no -reflow.  Actually it is a  misnomer , and  ideally it should be called “no flow” because  normal distal flow  does not  occur (After PCI)  in the first instance  to get interuppted  later on  and be labeled as  no re-flow.  .The only positive effect of PCI in these situation is blood flow would have improved by few centimeters ie till it reaches  but falls short of myocardium . In fact no reflow , can be termed as  glorified and concealed  terminology  for  PCI failure . It needs urgent action . No reflow is also called as myocardial epicardial dissociation.

Mechanism of no reflow.

 

 

Coronary  microvascualr plugging  is mainl  due to thrombus and atheromatous debri , myocardial  edema , microvascualr spasm may also contribute.

Where can it occur ?

  • First described in cath lab, especially following primary angioplasty.
  • It can very  well happen following thrombolysis in STEMI.
  • Can occur in venous grafts.

How do you recognise no reflow?

In cath lab it will be self evident from the check angiogram. Some times it is less obvious and may  require, myocardail blush score, TIMI frame  count, contrast echocardiography, PET scan etc. In post MI a very simple method to recognise this entity could be the observation of persistent ST elevation in ECG .

Treatment.

                                 Extremely difficult. Almost every coronary vasodilator has been tried.(Nitrates, nicorandil, calcium blockers, etc).Success is less than 10%.  High pressure flushing with saline inside the coronary artery is advocated by some.Others believe it’s dangerous to do it. So prevention is the key. Avoid doing PCI in complex, thrombotic lesions. Use thrombus suction device like export catheter(Medtronic). Distal protective devices are double edged devices , useful only in experienced hands.

  Unanswered question

What is the size of the particle (thrombotic and atheromatous  debri)  the   coronary microcirculation safely handle and push it into the coronary venous circulation and the coronary sinus for disposal ?

 If we can lyse the thrombus into micro particles by some mechanism and make it traverse the coronary circulation this complication of microvascuar plugging can be treated and prevented .

What is the final message ?

  • No reflow is relatively common condition during emergency PCI done for ACS patients
  • More common in complex thrombotic lesions.
  • Can also  occur in STEMI
  • Treatment is often vexing . In fact the treatment of this condition is so difficult , it can be termed  almost synonymously with “Failed PCI”
  • Prevention is the key
      
Post a comment
Write a comment:

Related Searches