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Archive for the ‘cto chronic total occlusion’ Category

We know, The Mysterious Alibaba cave opens  with a voice password . . . legend  tell us it had unlimited hidden treasures. It would appear , CTOs mimic the cave in several ways. What is inside ? Should we open it ?  Can we come out safely ? Do we have any magical password in cath lab to get across the complex tissue boulders ?,   every cardiologist would love to have one !

chronic total occlusion alibaba cave corsair fileder xt pronova guideliner micro catheter asahi cart reverese cart cross boss sting ray

Dear CTO,Open Sesame . . . I have come with all the wires you love !  Please let me in !

Indication

“CTOs are never an emergency  . . .but please realise  we can very easily create one  while resuscitating a dead snake  ! 

Don’t think hard on evidence , then , you may not do a single case of CTO in your life .Forget all those pessimistic trials like OAT,COAT, etc and the recent ones DECISION-CTO. Ignore all guidelines. Ask your patient, and his insurance company , if they are willing , reserve the cath lab and get ready.

Pre-procedure  planning

Spend at least a hour to analyse the CTO Imagery one day prior and create n action plan.

Keep knowledgeable staff for assisting , but never ask for fellow colleagues help because it hurts our ego !  Cardiac surgeon’s back up is a welcome addition even if it’s on paper.

If possible , try to ask the patient genuinely ,what is his symptom at least once !  before starting the procedure. 

Timing of the procedure.

Don’t post a CTO patient  either on a busy Monday morning  or lazy Friday afternoon.

Hardware Inventory

The wires ,catheters, the balloons form the essential tool box .There is more than a  handful of coronary automobile companies manufacture this .It is all about metallurgy , knowledge of wires, catheters , and tip thickness, (Bullet shaped as in Asahi ) , slipping , hydrophophic or philic,  polymer coating , trackability, pushability , memory etc etc.

Guide wire tip morphology is as Important as the  Lesion characteristics !

Analysis of the lesion (Probably most important)

Unlike conventional PCI we have no initial target.We need to poke first and find the target next ! Distal vessel status  is most important ( Careful review of retrograde filling  through collaterals could give more information than CT angiograms .Calcification, diffuse disease can be a real hurdle)

Lesion morphology

Softness of lesion has to be felt (Requires good wire which has sensor (Paccinian corpuscles and Merckle disc ideal ?) I guess the cortical tactile feel is as vital as the  intervention expertise .I know at least one diabetic colleague of mine who finds it difficult  to cross a CTO  and admits he never found it easy to feel  the lesion through the wires . Autonomic dysfunction ?)

Operator  expertise

(Note: These are like reading  swimming guidelines , you can’t learn in the shores reading books ! you have to plunge !)

Many techniques are proposed .Sequential approach (Ironically experts are licensed to use  specialized wired wires directly .Beginners  are advised to go with non specialized hardware and escalate step by step) Some centers are blessed with new age weapons like cross Boss and sting ray that confront the lesions in multiple frontiers. (Carpet bombing?)

CTO playground. : Its essentially a coronary contact sport with expert septal surfing , tunnelling, knuckling , kneeling , bending . Of course , It  can end up in a gratifying win in few , still most of us tend to play this game without a goal (post !)

They are basically about poking the head of the lesion and trying to cross an occluded vessel  millimeter  by mm towards the presumed distal vessel in an Imaginary trajectory. Proximal cap, central core ,the blind tunnel , distal capsule and exit points each must be successfully conquered.

CTO crossing is  the ultimate capacity of the operator to realise and feel the position of the wires in true lumen and their confidence levels in their conviction!

Multiple wires up to three are used some times to poke the lesion two of them are used to shut the false tracks and the other one is expected to enter the true lumen (Looks too good on theory !) . These are referred to in as many terms like parallel wire see-saw , CART ,Reverse CART etc .Retrograde techniques do help us but has no magic solutions.The lumen contrast , guide wire tip movement and its  side branch entry  would help.

Tacking complication :Always anticipate , it’s not negative mind set to look for it  !

Keep pericardiocentesis kit , covered stents , micro  snares and other retrieval devices ready in cart. Your support staff should be well versed with what is happening around them. Some of  the dye leaks and stains are safe .They imply minor perforations that form  sealed hematomas  (The plane of perforations also matters. myocardial (ab-pericardial ) leaks are well tolerated .Distal perforations are also safe as long as CTO is not opened ) Online echocardiography should be readily available to monitor  pericardial space leak.

When bleed into pericardial space is life threatening , A comical, but life saving option is to close the artery and restore the CTO  its original state and come out of the lab quietly ! 

Newer Imaging guidance : Can be useful , still may not matter much  when considering the interventional acumen .

CTO PCI : Time as therapeutic end point.

CTO is not an endless game with out time frame .In my opinion it shouldn’t cross 45 minutes each as in a  soccer  game with a brief  strategic time out and of course with liberal use of ,yellow and red cards

Future directions

Japanese are the ones who pioneered  CTO Interventions . We expect more Innovations ! Is it the forward looking IVUS ? It is akin to tunneling for underground metro train with GPS guiding .If you can mark the proximal and distal  points , rest will be be taken care by mortised self tunneling catheters from Robotic arms steered by sophisticated algorithms.

Final  message

CTO PCI remains a real Interventional challenge. We are often double blinded  in both directions (antegrade as well as retrograde ). Needs much effort ,time, hardware and most importantly a non fatigued mind and body. The benefits we get may vary  between  gratifying to outright mediocre .Of course , it surely satisfies operator ego and express pride and courage !

Is crossing and stenting  a CTO  synonymous with true success ?

Yes it is , for the cardiologist and  the hospital  . . . I’m not sure about it for the patient !

In this  sense , CTOs  mimic the mysterious Alibaba cave that tempts us with Imaginary treasures but can trap us with a wrong password !

Post-Ample

* Who should CTO PCI  ?

I have seen  young , enthusiastic cardiologists with Immature support staff attempting CTO in remote sub- urban settings ! Though patience and expertise are essential ingredients, some amount of organised training and hardwares make CTO PCI safe and effective. Enthusiasm and affordability alone can’t be an Indication for this complex set of coronary lesions.

Reference 

 

I still wonder why  this vital paper was never published , it was just presented in the Annual ACC conference March 2017

http://www.eurocto.eu/

 http://www.cct.gr.jp/

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Hot debate in STEMI

Acute total obstruction (ATO) of coronary artery is an emergency .Opening it  by pharmacological or catheter is the  standard ( logical ) protocol.However, time plays a crucial role in this coronary re-perfusion game.It can either be a sure shot of success or end up in total spoilsport. One more issue as important as time is from the overflowing scientific data  fired  by different regulators  in conflicting directions  (Also called knowledge) .

What to do with STEMI coming late ?

  • ATO with cardiogenic shock is an  absolute emergency at any time.
  • Symptomatic ATO  other than CS beyond 24 hrs still  considered  emergency for most.(Symptom should be true angina )
  • Hemodynamic instability is misunderstood term . Stabilizing it medically is not forbidden.

Asymptomatic stable ATO  beyond  24-72 hours can be  semi emergency, true emergency or as cool  as a cucumber depending upon the cardiologist’s wisdom , experience or inexperience  and the  Institutional Integrity !

*Please be reminded ,LV dysfunction is not an absolute indication for urgent intervention unless it is due to ischemic dysfunction attributable  to a critical non IRA lesion

When does a ATO become safe CTO ?

1 month , 3 months, 6 months ?

Why we are  not defining a sub-acute ATO ? or CTO in transition   ?

Is living peacefully with sub acute ATO or CTO a coronary crime ?

We don’t require a debate , whether these  questions are worth answering  or not !

Final message

Though cardiac professional  are committed  to open up occluded arteries to save  lives , reality is repeatedly teaching different stories ! The greatest danger of keeping an artery open( In disputed indications ) is the newly conferred risk of sudden closure and the attendant  unpredictable aftermath !

Or should we conclude : Living with CTO is ok , but don’t intentionally create one by denying PCI in late  post STEMI ATOs

Anti-thought

Arguing closed artery is better than an open artery is straw man argument and inability to interpret positive things in science.  However it may still be right  when science suffers  from hostile incursions from non academic forces.

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Those who answered  “Yes” ,  can leave this article . Those who answered  “No” read further .

* Logic would tell us myocardial revascularisation should correct  stress induced ischemia and it  should disappear promptly  . This does not happen in all cases  real world  ! That is  why medicine is  different  from mathematical science .

Some of the  reasons for  persistence of stress positivity even after an apparently successful PCI are  . . .

  1. Incomplete  correction of ischemia. (Ideally  to be referred as failed PCI )
  2. Error in Identifying culprit 9Angina related artery ) .Common feature of poorly worked up  multivessel CAD.
  3. Re-stenosis /Re-occlusion
  4. Doing very early stress test without giving time for revascularisation to work *
  5. Rapid progression of non culprit lesions .(Sub -optimal medical management )
  6. Chronic N0-Reflow phenomenon  surrounding  area of infarct .(Especially in  PCI of CTOs)
  7. Dyskinetic  or grossly remodeled ventricular segments  can result in non ischemic positive EST response (ST drag **)
  8. Associated systemic conditions especially  Anemia/ SHT & LVH -(False positive )
  9. Many diabetic patients may  continue to show stress ischemia due to  small vessel disease.
  10. A  patient with  syndrome X  characters  can have incidental  epicardial lesion as well . In such a patient EST will always be positive .

* Optimal time to do  EST  for assessing the  efficacy of  PCI/CABG is not established .Six months may be the reasonable point .If done within 2- 3 months it may  end  up  in embarrassment for the Interventionist . (So only it is kept at 6 months , this also help us  greatly  as  we can always blame it on poor life style control and progression of  the disease !)

** No reference  for this  , a  personal observation .We know  Q leads following MI ,  will show ST elevation during stress test especially if the segments are dyskinetic  . In leads diagonally opposite to q leads ,  ST depression is observed . This may not be  a evidence for true  ischemia . It probably represents   ST drag due to mechanical stretch .

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Japanese are the pioneers in CTO reopening .(I understand they do less   CABG surgeries  for  religious reasons ) CTO is the ultimate test for cardiologist patience .  it may  take  hours to open up a CTO (or even to abandon it .)  Here is a  success prediction tool from Japan .

cto score success in chronic total occlusion

j cto score  sheet

Source courtesy  : JACC: Cardiovascular Interventions Volume 4, Issue 2, February 2011

Reference

http://www.sciencedirect.com/science/article/pii/S193687981000912X

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chronic total occlusion cto tips and tricks

Answer :

While each one of the above factor appears very much important  morphology of the lesion is the  clear winner  ( Which includes , the content of the lesion , hardness , micro channels , thickness of the proximal and distal caps, the length and   tortuosity   of the CTO     ( which is invisible ) the collateral status will ultimately determine the success)

It is becoming increasingly clear  cardiologist expertise is getting less and  less important .

Finally ,  it must  be told to our  younger generation of cardiologists , crossing a  CTO and deploying a stent  is not synonymous with success .It should result in long term sustained distal flow and make a significant impact on the patients symptoms (If at all any !) and survival.

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