Feeds:
Posts
Comments

Posts Tagged ‘pfo’

It was in 1984   this paper came from mayo clinic proceedings .

Hagen PT, Scholz DG, Edwards WD. Incidence and size of patent foramen ovale during the first 10 decades of life: an autopsy study of 965 normal hearts. Mayo Clin Proc. 1984;59:17-20.

When interventional   cardiology was not even in infancy . Now it remains the only data base of nearly 100o hearts  studied  after autopsy .

After reading the article  I got  few surprises

  • The mean  incidence  is 27.3 % of general population ( That is  27 crore people with PFO  in India )
  • In first three decades it goes up to 40 % .
  • PFOs size increase with age  due to stretch of inter atrial septum
  • It measures 3.4mm  in the first decade and it can grow up to 5.8 mm in later decades .

http://download.journals.elsevierhealth.com/pdfs/journals/0025-6196/PIIS0025619611632606.pdf

Mayo clinic continues to be pioneers in  providing vital  research about PFO

Following  is another excellent review article  on PFO and stroke

patent foramen ovale and stroke

Read Full Post »

Patent foramen ovale (PFO) is the new generation hole in the heart for  21st century  cardiologist. Present in about 20% of population  , would correspond to 140 crore  “man holes”  as  on  2012   in this planet. PFOs are embryological remnants across the inter atrial septum.

These minute  holes measuring few mm  are largely a  benign finding .In the recent  decades , it is being increasingly debated these holes  may  not  be innocent after all .Extensive  use of echocardiography in recent times   has contributed to  the awareness  as well as anxiety.

Evidence  is mounting  linking PFO to

  • Migraine,
  • Stroke and
  • Peripheral embolism.

While the above   observation may be true  ,  the  fact that >100 crore people have this entity   , raises  a serious question ,  as labeling  all of  them as heart disease will create chaos among the already health obsessed   population .

So , the main purpose should be ,  to identify the high risk subsets* of PFO population .(This will be a <5 %  at the most). People with PFO may  carry  a mental  stigma because it is referred to as a hole in  the heart by the  general  public .For many  the sense of living with a hole in heart is often more damaging than the hole itself ! (Incidentally , many develop  migraine only after reporting about this hole !)In a strict sense  PFO  is not a hole , rather  it is a communication it may be tunnel  or  slit like .It is argued physician should avoid calling PFO as a hole .

*What is a significant PFO ?

  • Large PFOs >5mm
  • PFOs that shunt blood
  • PFOs with septal aneurysms
  • PFOs with documented stroke or embolism
  • PFOs with atrial chiary network
  • PFO in  persons with systemic pro-coagulant states (Except probably in  pregnancy )

Final message 

PFO is a common residual congenital  atrial septal  anomaly . Usually  benign  . One can  live with it perfect harmony. Only occasional patients  are  at risk.

So the prime job of cardiologists is to not diagnose and create panic about  this entity. rather reassure  them (Is it better do not reveal to them if it is found incidentally ? Patient empowerment group would call  this a  foul !  I do not support blind empowerment  )

At the same time our main  aim is to identify the  high  risk subsets who are prone for events.

Closure of   PFO with device is required in a fraction . (*By the way ,  if   PFO is really dangerous ,  why It is never an indication for surgical closure ?  )

Reference

Your  search for best information  on PFO  would end here .  Here is  land mark   article  in JACC  by  Hara   also contributed by  Renu Virmani . A US  Japan  combines initiative  : A must read by every cardiologists

http://content.onlinejacc.org/cgi/reprint/46/9/1768.pdf

http://www.anesthesia-analgesia.org/content/93/5/1137.full

Read Full Post »

The link between migraine and PFO is  . . .

  1. Incidental  & man-made
  2. Almost certain
  3. Definite
  4. A wild imagination

Answer : One of the above  is correct  , but  we do not know  which one is   !

There has been many  patients with TIAs , cryptogenic strokes , who  had  documented PFO  ,complain of prolonged  head aches . This was the beginning of suspicion of PFO as a cause for migraine .Then the device industry foresaw a huge opportunity . Things began to unfold and  the concept is currently as nebulous as it can be .

Mechanism of migraine in PFO

(All are  presumptions )

  • Right to left shunting of  vasoactive amines from venous circulation (Serrotonin)   which bye- passes  the lung where they are supposed to get filtered.
  • Venous micro emboli (Antiplatelet agents reduce migraine as well as TIA ! )
  • Hypoxia transient – cerebro vascular hypersensitivity
  • Atrial naturetic  peptide spills more into systemic circulation through  PFO

Counter arguments

  • If right to left shunting is causing the migraine , why it  is not fully disappearing even after closure of  PFO (MIST data with  starflex  device ,  migraine persisted in a significant chunk !)
  • What is the incidence of migraine in the  prototype  right to left to shunt situations like TOF, Eisenmenger , pulmonary AV fistula ?  if shunting is the mechanism , logically  migraine incidence  should be very high  in this population , but it is not .
  • Migraine occurs in 10 % of population, PFO  is present in 20%  .  What are  the chances of over lap ?  It could be the simple statistics at play !

Where is the evidence  ?  The mystery called MIST study.

This study , done in UK generated more controversy , which  it was supposed to remove  . Still  this  study is considered to be a major evidence for the link between PFO and migraine . Star flex device  was promoted by NMT medical Boston .

http://www.medscape.com/viewarticle/541260

Link to  best review article on PFO

http://chestjournal.chestpubs.org/content/130/3/896.full.pdf+html

Final message

The link between migraine and PFO can be a fact or myth depending upon our belief in current  methods of  research in  science. The issue is  debatable . Of course ,  one issue is probably  closed  forever  , even  if they  are  linked casually (or seriously )  device closure can  never be a  sensible treatment  option for migraine ! *

We  expect a  proof / disproof  in this   mysterious migraine -PFO  hypothesis very  shortly.  Of course , many  cardiologists  already  have their  own conclusions !

 

*Please note , PFO  device closure  for  stroke in young is a different story

Read Full Post »

  1. Left to right
  2. Right to left
  3. Can be in both directions
  4. No significant flow at all !

Answer :   Every response can be correct

The patent foramen ovale is a physiological orifice , which  becomes  pathological if persist into  adult hood .The incidence is estimated to be about 20 %  of the population (Amounts to 100 crore PFOs roaming  in our planet!). It makes  no sense  to  believe  just spotting  a  PFO  in routine echocardiography be termed  as pathological . But recently  (Adding much to  interventionist’s  delight ! ) the presence of which is being linked with migraine and stroke in young.

The size of the orifice can be from a single millimeter to one centimeter* . The direction of blood flow in PFO   is determined by the mean gradient across the orifice. It has to be  left to right  as the LA pressure is  generally   higher by few mm mercury  ,hence there is a small  tide of flow entering into RA with each left atrial filling or contractile wave .(v and a ). This  quantum is miniscule and has no hemodynamic significance in most life situations.

* Some call( Wrongly ) 1cm PFO  as small ASD.

When can Right to left to flow occur ?

When the right atrial pressure increase more than LA pressure it is obvious  blood can enter LA . It is well-known this occurs  in any pathological situations like RVOT obstruction severe PHT , tricuspid valve obstructions etc.

Physiological  Right to Left flow :

Forced expiration (Valsalva) can cause transient  right to left flow. This  may happen in many real life situations like straining, heavy isometric exercise, blowers, muscians  etc.

Which is clinically  significant ?

Left to right or right to left  ?

Left to right shunting is rarely an issue as there is no systemic  desaturation.

Right to left  shunting  can be  important for two reasons

  1. Arterial desaturation( transient )
  2. Shifting of venous debris into arterial side  can result  in potential paradoxical embolism .(This can be air, clot fat , amniotic fluid etc)  This is the reason stroke in young is closely linked to presence of PFO.

PFOs during positive pressure ventilation

PEEP is a classical example where a right atrial positive pressure ,  shunts the blood in pulsatile manner into left atrium .

Platyponea  hypoxia  syndrome .

This is  postural right to left shunting  across PFO .It  is a less recognised (but a common entity) where -in ,  when the patient  lies down there is a  right to left PFO shunt and transient hypoxia .This is often corrected as the patient sits up. The reason being  the valve of PFO , the   door like flap  which guards  the orifice  ,  is aligned   in such a fashion , it  opens up in a  lying posture(Aided by gravity ?)  , shuts down in  sitting posture .It should be noted  The PFO valve is not a constant feature  . The size  of this valve , the stiffness , the hinge points , ability to  float  are highly variable .Hence the clinical variation in PFO syndrome.

The IAS septal aneurysm is an  important variation where the valve of PFO balloons out into left atrium  may become a nidus for thrombus or a focus for atrial arrhythmias .

Stroke in young  and PFO  :This  topic  deserves a separate article

Reference

Anatomy

Excellent PFO images from Yale university library  ( http://www.yale.edu/imaging/chd/e_pfo/index.html)

 

http://chestjournal.chestpubs.org/content/100/4/1157.full.pdf+html

http://chestjournal.chestpubs.org/content/118/3/871.long

http://www.anesthesia-analgesia.org/content/93/5/1137.full.pdf

Excellent PFO images from Yale university library

Read Full Post »

Patent foramen ovale is probably  the commonest  congenital heart defect.  (Bicuspid aortic valve will run close to it ! )

Note : PFOs  cannot be  called as a  true disease , since it is a  benign anatomical defect with little or no hemodynamic impact.

Consider  this scenario . . .

The incidence  of PFO could be as high as 20% of adult population. It means nearly 100 crore people of this planet  will suffer from this entity !

When does it become significant ?

Paradoxical embolism : In young persons with cerbro vascular accident , PFO s are more commonly observed , implicating some form form of venous to arterial embolus .

In some persons it is believed , it can shunt few CC of blood from right atrium to left atrium at times of right atrial hemodynamic stress. Like severe physical  straining  (valsalva like )

In seriously ill ventilated patients  PFOs can worsen the  hypoxia especially with  PAPP  mode .

When does it become a life saving savior ?

  • In patients with DTGV and intact IAS  even a a small PFO can sustain a life  till , emergency surgery or intervention is done .
  • In patients  with severe  pulmonary hypertension the PFO may act like a safety valve, opening at a critical moment and decompress the  right atrium and which  indirectly relieves  the RV wall stress as well .

Fancy relationships

Now , it is  considered PFO  is related to migraine by some means ! ( What means !)  The belief has strong evidence base that has lead  the aggressive  interventional cardiologists to  find a new hole to close  . This indication ,  if  approved will have a perennial supply of patients  as there are 100 crores of them .

How will you differentiate a PFO from a small ASD ?

Size alone can be a useful pointer in differentiating a ASD from PFO.

A PFO can  measure  between  2 to 10mm  ( most measuring between 4-6mm diameter)

Size matters !  The upper limit of PFO is the lower limit of ASD .

Practical experience suggest any defect  above 7mm should alert  us about the possibility of true ASD.

Other useful clues

  • PFO are always restrictive  (Use pulse doppler probe right across the PFO /ASD in subcostal view .If you pick up a gradient > 4mmhg (velocity 1 m /sec) PFO is confirmed.
  • Most ASDs do not show any significant  gradient
  • Right ventricle and right atrium should be normal in PFO  (Unless due to some other cause )
  • Doppler flow across  pulmonary valve can be very useful . If it exceeds 1.5m/sec , left to right  shunting is likely to be significant and PFO is unlikely.

Is there an entity called restrictive ostium secundum ASD ?

If so ,  how will you  differentiate it from PFO ?

Yes , we have ,especially in  cyanotic heart disease

Like TGA , Ebstien etc .

Isolated restrictive secundum ASD is extremely rare .

* There is no way to differentiate a restrictive ASD from a similar sized PFO .

What is the role of TEE in diagnosing PFO

It has a major  role in delineating the IAS anatomy .

Read Full Post »

Atrial septal defect is one among the commonest congenital heart disease .After years of controversy, there is consensus  now , all significant ASDs  need to be closed ,  at whatever age it is detected.

This rule does not apply to small ASDs without chamber  right atrial and right ventricular dilatation. These defects and PFOs need not be closed .

Over the years , the  controversy  has shifted  from   Should we close ?  to  How to close ?

There are two options available : Device closure , Surgical closure

asd closure device www.drsvenkatesan.com

asd closure www.drsvenkatesan.com

The following table compares the both treatment  modalities

( Personal perspective )

asd device closure 4

Final message

Device closure is a complex, costly, often  difficult  and  error prone   cardiac procedure .It needs long term follow up and may  carry a life long risk of major cardiac complication.It is useful only in selected subset of ASD patients. Surgical closure prevails over device closure in most situations.

Is this article  has biased view against this  emerging pediatric  interventional procedure of ASD closure ?

It may appear so . But that is the reality as on 2009 !.May we hope technology evolves further and take our surgeons head on .

2012 update on ASD device closure .

The   hard-ware  as well as the  expertise has   improved a lot and it is on right track to become a real challenge to surgery.

The only issue again is the availability of  rims to mount the device . Another  realistic and sensitive issue  which  have I come across is  , many interventionist cardiologist do feel awkward  when they experience  unexpected rim shortage on table.  They should realise it is not their  fault.

Always be ready to abandon the procedure and refer to the surgeon , according to your  true conscience 

After all , improperly delivered device is  a life long pain for the patient .He has come to you with a  great belief  isn’t !

2014 update

Device closure for most ASDs in both children and adult is  now possible with high degree of success. We have crossed about 50 patient experience. And  I am truly amazed  , how within a short period the device closure is about to conquer the crown from the surgeons ! (Exciting new data are coming from   my colleague Dr Gnanavelu from  the new Super specialty hospital of Government of Tamil Nadu Chennai. )

 

Reference

Aortic erosion following ASD closure

http://content.onlinejacc.org/cgi/content/full/45/8/1213

Read Full Post »