Saturday, 28 December 2013

CCSVI Saturday



OBJECTIVE Chronic cerebrospinal venous insufficiency (CCSVI) is a condition associated with multiple sclerosis (MS) and manifested by stenoses in the extracranial venous circulation. There is a need for an objective non-invasive assessment of CCSVI that is able to accurately identify the location of stenoses and quantify physiological changes in blood flows following treatment.
METHOD:A duplex ultrasound method, extracranial duplex ultrasound (ECDU), is described where the internal jugular veins (IJVs) and vertebral veins (VVs) were examined in the supine and sitting position before and after venoplasty in eight patients with clinically diagnosed MS. High-resolution B-mode imaging was used to detect obvious stenoses, intra-luminal membranes, valve abnormalities and vein wall thickening. ECDU was then used to assess blood flow including reflux. To assess obstruction, venous blood volume flows (BVFs) were taken bilaterally from the proximal (J1), mid (J2) and distal (J3) segments of the IJVs and the mid cervical VVs. To assess cerebral perfusion, bilateral BVF measurements were taken, in the supine position only, from the proximal internal carotid arteries (ICA) and mid cervical vertebral arteries (VA). The global arterial cerebral blood flow (GACBF) was then calculated as the sum of the ICA and VA measurements.
RESULTS: Pre-venography ECDU detected IJV stenoses or obstruction in all patients. Venography findings were consistent with those of the pre-treatment ECDU with the exception of the detection of bilateral IJV stenoses in two patients diagnosed with unilateral IJV stenosis by ECDU. A significant improvement in GACBF was evident following venoplasty (p < 0.05). A trend to improvement in the post-treatment BVFs of both the IJVs and the mid cervical VVs was also observed. This improvement was most marked in the left VVs (p = 0.052) and the J2 segment of right IJVs (p < 0.05).
CONCLUSION: The ECDU examination described provides a reliable objective assessment of IJV and VV stenoses and, with the use of BVFs, can quantify the degree of obstruction. These results support the use of ECDU as a non-invasive post-operative assessment of the success of venoplasty. The ability of ECDU to measure GACBF provides an additional parameter to monitor vascular pathophysiology in MS patients. The current findings support the view that the early symptomatic benefits observed after venoplasty for stenoses in the extracranial venous circulation may be the result of increased cerebral perfusion.

Taking a step back to look at the overall picture, I believe 2013 has been on balance a negative year in this aspect. 



It is clear that the 100% concordance of CCSVI with MS is an unsustainable view. However the criteria applied to detect CCSVI does seem to occur in more MSers than Non-MSers, although some studies find it a vanishingly rare occurrence.

However, it is also the case that CCSVI criteria occurs in non- MSers. CCSVI criteria are more common in older MSers and so it is perhaps consequential and not causal. Therefore the causal link is clearly wrong. Those in support argue that the techniques used that do not show CCSVI are not fit for purpose, but one should argue that the goal posts are being shifted when the hurdle is being not being cleared. 

More problematical is that the CCSVI diagnostic criteria are not stable over time and therefore there is clear problem in any clinicial study on this subject. A trial by CCSVI protagonists was stopped because of apparent worsening and whilst other unblinded studies suggest some perceived benefit, it was evident that this was typically short lasting, for a few months. Therefore the chances of success of long term trials lasting years are minimal, 

Personally I hope the ongoing trials actually show some benefit, but taking a more dispassionate view I am not expecting this. This whole saga has elements that have reverberated and repeated in MS history....what will be the next treatment option that you can bypass the established medical profession. 

Hopefully 2014 will bring even more clarity on this issue.