distal branches of ICA

branches

meningohypophyseal trunk
inferior hypophyseal artery

supraclinoid segment
 c4
ophthalmic artery
superior hypophyseal a
posterior communicating
anterior choroidal

HEPARIN INDUCED THROMBOCYTOPENIA (HIT)

Antibodies v. factor 4 platelets complexes
10 x more common with heparin than with LMWH
20-50 percent get arterial or venous thrombosis
platelet count is less than fifty percent normal
may use a direct thrombin inhibitor eg. argabotran

basic science notes
heparin and LMWH are indirect thrombin inhibitors as they do not act on fibrin bound thrombin.  By contrast, the direct inhibitors (hirudin, argabotran, bivalirudin) inactivate fibrin bound thrombin.

At an injury site, F VIIa (extrinsic pathway) and tissue factor are activated.  Thrombus propagates when F IXa binds to cofactor VIIIa (intrinsic pathway) and forms a complex that binds F X.  Xa binds Va to form prothrombinase that converts prothrombin to thrombin.  XI promotes Xa, final step is conversion of fibrinogen to fibrin

Statins on vessels basic science

Increase synthesis, decrease degradation of LDL receptors on heptatocytes
-LFT's increase in one percent
- tissue factor is PRO coagulant in enthothelial surface as is Va, F VIII
-heparin and prostacyclin are anticoagulants in endothelium, also NO, enodog tpa, heparin like substance

RE: pfo Studies

I have included 2 articles :

 

Transcranial Doppler to detect right‐to‐left shunt in cryptogenic acute ischemic stroke

Paola Palazzo, ^{1 , 2} Pierre Ingrand, ³ Pierre Agius, ⁴ Rafik Belhadj Chaidi, ⁵ and Jean‐Philippe Neau ¹

^{I include this for your review because it is 2019,  because all the patients were done brachial, and because the references are very well done.  It does not address the femoral route}

Sensitivity of brachial versus femoral vein injection of agitated saline to detect right‐to‐left shunts with Transcranial Doppler

Rubine Gevorgyan MD

Alice Perlowski MD

Michael Shenoda MD

M. Khalid Mojadidi MD

Harsh Agrawal MD

Jonathan M. Tobis MD

First published: 09 January 2014

https://doi.org/10.1002/ccd.25391

Cited by: 4

Conflict of interest: Nothing to report.

Read the full text

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Abstract

Background

Transcranial Doppler (TCD) can detect a right‐to‐left shunt (RLS) with high sensitivity but has a 5% chance of a false negative study. TCD is usually performed with injection of agitated saline into an arm vein. We compared the sensitivity of TCD performed from the brachial versus femoral veins.

Methods

Patients presenting to the cardiac catheterization laboratory for percutaneous closure of a patent foramen ovale (PFO) were enrolled. Power M‐mode Transcranial Doppler (Terumo 150 PMD) was conducted. After injection of a mixture of 8 cc of agitated saline, 0.5 cc of air, and 1 cc of blood into the brachial vein, embolic tracks were counted over the middle cerebral arteries. The degree of RLS was evaluated by TCD at rest, and with Valsalva at 40 mmHg aided by visual feedback with a manometer device. The test was repeated using femoral venous injections.

Results

Sixty five patients were enrolled, mean age 52, 43% male. TCD grades were significantly higher with femoral injections compared to brachial injections at rest (p<0.0001), and with the Valsalva maneuver (p<0.0001). The presence of a RLS was confirmed by intracardiac echocardiography (ICE) during cardiac catheterization in 62 (95.4%) patients.

Conclusion

The sensitivity of TCD for detection of RLS is increased when agitated saline injections are performed through the femoral vein. In patients with a high clinical suspicion for RLS, low TCD grades obtained with traditional brachial venous access should be interpreted with caution. When possible, a repeat study using femoral venous access may be considered. © 2014 Wiley Periodicals, Inc.

I have included this second article from 2014 as responsive to your note.

cTCD by brachial  injection has a 93% sensitivity and a 97% specificity.   I am not sure how much better "2X as good" is.  The introduction of a 1.5%-8% complication rate with a femoral catheter and the added cost may be justified under some circumstances.

The assumption is that the TIA or CVA is, in fact, cryptogenic,( that it has has been fully evaluated with Holter monitor, coag studies etc)     In this circumstance, negative TEE in which satisfactory valsalva has been noted along with a negative good quality cTCD for RLS leaves the circumstance to appear to be truly cryptogenic. 

The benefit of transcutanious PFO closure has always been clear to me, but the proof of benefit over ASA does require some statistical yoga.  This leaves the clear option of treating a truly cryptogenic group with ASA.  The number of spots on the MRI might help decide

I wonder if those relatively rare circumstances might be best resolved with a cardiac cath. ( especially if events are recurrent on ASA)  PVL can certainly participate in a f/u cTCD with femoral catheter.   We are not set up to do it in the PVL

-----Original Message-----
From: djacobs272 <djacobs272@aol.com>
To: adam.waldman <adam.waldman@orlandohealth.com>; mmenkin <mmenkin@aol.com>; ca.rosado <ca.rosado@gmail.com>; dhj1.strokenotes <dhj1.strokenotes@blogger.com>
Sent: Wed, Apr 24, 2019 9:39 am
Subject: pfo Studies

from Thaler DE and Cramer SC Paradoxical embolism in stroke in  Caplan LR, Biller J. Uncommon Causes of Stroke

"The choice of vein used to introduce echocardiographic contrast influences the sensitivity for PFO detection. Blood entering the right atrium via the inferior vena cava is directed towards the interatrial septum where PFOs are located whereas blood from the superior vena cava tends to be directed towards the tricuspid valve. Studies have been consistent in finding a 2.5-fold increase in diagnostic sensitivity when the contrast medium is injected via the femoral rather than the antecubital vein (Gin et al., 1993; Hamann et al., 1998).

Caplan, Louis R.; Biller, José. Uncommon Causes of Stroke (pp. 565-567). Cambridge University Press. Kindle Edition.

full citations for above:

Gin, K., Huckell, V., and Pollick, C. 1993. Femoral vein delivery of contrast medium enhances transthoracic echocardiographic detection of patent foramen ovale. J Am Coll Cardiol, 22, 1994– 2000.

Hamann, G., Schatzer-Klotz, D., Frohlig, G., et al. 1998. Femoral injection of echo contrast medium may increase the sensitivity of testing for a patent foramen ovale. Neurology, 50, 1423– 8.

ALL MY TAKE

I ASSUME ONE HUNDRED PERCENT OF OUR STUDIES BOTH TCD AND TEE BUBBLE ARE DONE THROUGH ARM VEIN BUT RHEOLOGY SHOWS FEMORAL VEIN IS 2.5 X AS GOOD.  PERHAPS WE COULD CONSIDER DOING THESE STUDIES FEMORRALLY SECOND LINE IN CHALLENGING PATIENTS SUCH AS WE HAVE HAD LATELY?  LOOK FORWARD TO EVERYONE'S THOUGHTS

DJ

Re: pfo Studies

I have included 2 articles :

Transcranial Doppler to detect right‐to‐left shunt in cryptogenic acute ischemic stroke

Paola Palazzo, ^{1 , 2} Pierre Ingrand, ³ Pierre Agius, ⁴ Rafik Belhadj Chaidi, ⁵ and Jean‐Philippe Neau ¹

^{I include this for your review because it is 2019,  because all the patients were done brachial, and because the references are very well done.  It does not address the femoral route}

Sensitivity of brachial versus femoral vein injection of agitated saline to detect right‐to‐left shunts with Transcranial Doppler

Rubine Gevorgyan MD

Alice Perlowski MD

Michael Shenoda MD

M. Khalid Mojadidi MD

Harsh Agrawal MD

Jonathan M. Tobis MD

First published: 09 January 2014

https://doi.org/10.1002/ccd.25391

Cited by: 4

Conflict of interest: Nothing to report.

Read the full text

PDF

Tools

Share

Abstract

Background

Transcranial Doppler (TCD) can detect a right‐to‐left shunt (RLS) with high sensitivity but has a 5% chance of a false negative study. TCD is usually performed with injection of agitated saline into an arm vein. We compared the sensitivity of TCD performed from the brachial versus femoral veins.

Methods

Patients presenting to the cardiac catheterization laboratory for percutaneous closure of a patent foramen ovale (PFO) were enrolled. Power M‐mode Transcranial Doppler (Terumo 150 PMD) was conducted. After injection of a mixture of 8 cc of agitated saline, 0.5 cc of air, and 1 cc of blood into the brachial vein, embolic tracks were counted over the middle cerebral arteries. The degree of RLS was evaluated by TCD at rest, and with Valsalva at 40 mmHg aided by visual feedback with a manometer device. The test was repeated using femoral venous injections.

Results

Sixty five patients were enrolled, mean age 52, 43% male. TCD grades were significantly higher with femoral injections compared to brachial injections at rest (p<0.0001), and with the Valsalva maneuver (p<0.0001). The presence of a RLS was confirmed by intracardiac echocardiography (ICE) during cardiac catheterization in 62 (95.4%) patients.

Conclusion

The sensitivity of TCD for detection of RLS is increased when agitated saline injections are performed through the femoral vein. In patients with a high clinical suspicion for RLS, low TCD grades obtained with traditional brachial venous access should be interpreted with caution. When possible, a repeat study using femoral venous access may be considered. © 2014 Wiley Periodicals, Inc.

I have included this second article from 2014 as responsive to your note.

cTCD by brachial  injection has a 93% sensitivity and a 97% specificity.   I am not sure how much better "2X as good" is.  The introduction of a 1.5%-8% complication rate with a femoral catheter and the added cost may be justified under some circumstances.

The assumption is that the TIA or CVA is, in fact, cryptogenic,( that it has has been fully evaluated with Holter monitor, coag studies etc)     In this circumstance, negative TEE in which satisfactory valsalva has been noted along with a negative good quality cTCD for RLS leaves the circumstance to appear to be truly cryptogenic. 

The benefit of transcutanious PFO closure has always been clear to me, but the proof of benefit over ASA does require some statistical yoga.  This leaves the clear option of treating a truly cryptogenic group with ASA.  The number of spots on the MRI might help decide

I wonder if those relatively rare circumstances might be best resolved with a cardiac cath. ( especially if events are recurrent on ASA)  PVL can certainly participate in a f/u cTCD with femoral catheter.   We are not set up to do it in the PVL

pfo Studies

from Thaler DE and Cramer SC Paradoxical embolism in stroke in  Caplan LR, Biller J. Uncommon Causes of Stroke

"The choice of vein used to introduce echocardiographic contrast influences the sensitivity for PFO detection. Blood entering the right atrium via the inferior vena cava is directed towards the interatrial septum where PFOs are located whereas blood from the superior vena cava tends to be directed towards the tricuspid valve. Studies have been consistent in finding a 2.5-fold increase in diagnostic sensitivity when the contrast medium is injected via the femoral rather than the antecubital vein (Gin et al., 1993; Hamann et al., 1998).

Caplan, Louis R.; Biller, José. Uncommon Causes of Stroke (pp. 565-567). Cambridge University Press. Kindle Edition.

full citations for above:

Gin, K., Huckell, V., and Pollick, C. 1993. Femoral vein delivery of contrast medium enhances transthoracic echocardiographic detection of patent foramen ovale. J Am Coll Cardiol, 22, 1994– 2000.

Hamann, G., Schatzer-Klotz, D., Frohlig, G., et al. 1998. Femoral injection of echo contrast medium may increase the sensitivity of testing for a patent foramen ovale. Neurology, 50, 1423– 8.

ALL MY TAKE

I ASSUME ONE HUNDRED PERCENT OF OUR STUDIES BOTH TCD AND TEE BUBBLE ARE DONE THROUGH ARM VEIN BUT RHEOLOGY SHOWS FEMORAL VEIN IS 2.5 X AS GOOD.  PERHAPS WE COULD CONSIDER DOING THESE STUDIES FEMORRALLY SECOND LINE IN CHALLENGING PATIENTS SUCH AS WE HAVE HAD LATELY?  LOOK FORWARD TO EVERYONE'S THOUGHTS

DJ