Dr.S.Venkatesan MD

PTMC involves a critical step , where one has to cross  the IAS to reach the LA.The septal puncture remains  somewhat a blind procedure in fluoroscopy .(Echo can still assist us. )

Stitch effect is a rare complication where the needle pierces the intrapericardial space from the right atrial side and re-enter the left atria .This wrong way entry into LA may not be recognised  untill the sheath is withdrawn and a cardiac tamponade ensues after removal.

Where exactly the stitch  occurs ? What are  the anatomical planes ?

This usually  happens in the superior aspects of   IAS , abutting the roof of RA and LA . The alignment of IAS with reference to RA and LA is key a determinant.We know in mitral stenosis LA can outgrow the RA , bringing   superior aspect of LA  in a different  plane with reference to IAS  .The IAS puncture site may overshoot , enter the pericardial  space and  stitches the non IAS aspect of RA and LA together , of course  still guiding us  into LA through a false pericardial track (Which is not recognized )

Note : The intra-pericardial track can be more complex than we realise as a significant part of posterior LA is extra-pericardial and transverse sinus of pericardium can get involved as well.

Our understanding(mis ?)  suggests at least four different stitches are possible

1. IAS-Pericardial space -LA roof
2. RA-Pericardial space -LA roof

Other complex tracts (Based on theoretical assumptions . Please note , in  some of the fatal punctures the exact  route was not identified by surgeons even under direct  vision . )

3.RA-Pericardial  space -Extra cardiac-Reenter LA

4.RA-IAS -Pericardial space-Extracardiac -Reenter LA  ?

What are the possible bleeding sites in stitch effect ?

There can be two sites of active bleeding .One from RA exit point and other from LA entry point of needle.Extra-cardiac oozing can also occur if the needle has pierced the outer pericardium before entering LA.

Management

• Recognition is the key. It requires extra anatomic acumen to diagnose the false track before we insert and withdraw the sheath.Echocardiography should be liberally  used if you suspect a false track .
• Tamponade  is to be  drained promptly and emergency surgery is usually required if re-accumulation occurs.
• Closing the puncture site with devices has been successfully  attempted in few patients .A small ASD device (or a Plug ? ) is expected to close  the site of  puncture . Since the anatomy  can be complex ,one may need to  close with two devices , one on LA side and other one RA side .The radial force that closes the tear and long term retention of these device are not known .

Related topic

Other mechanisms of cardiac  tamponade during  PTMC