ISET 2011- Dr. Paolo Zamboni’s lecture on “CCSVI: What is it and What are the Duplex Findings?”
On 1/16/11, Dr. Paolo Zamboni spoke at the ISET 2011 conference in Miami, FL. The topic of his speech was “CCSVI: What is it and What are the Duplex Findings?” Dr. Zamboni explained that in his experience of Doppler screening for CCSVI using Duplex ultrasonography, he has found that the majority of venous abnormalities included two locations in the head and neck. Dr. Zamboni reported he has most often noted “intraluminal” defects or abnormalities inside veins. He stated these vein issues are called “truncular venous malformations carrying intraluminal defects” and are found, most often, in two locations. Those 2 locations include the IJV at the conjunction with the brachiocephalic vein and the location where the superior vena cava meets the azygous vein.
Dr. Zamboni further explained that screening using Duplex Doppler is best accomplished with properly trained technicians. Dr. Zamboni said that due to hydrostatic gradiant mechanisms related to gravity, head and neck veins change when a person’s position changes. Therefore, his 5 criteria for CCSVI screening are applied in supine and up-right positioning. In addition, pressures change in veins due to breathing movements—inspiration vs. expiration. Anatomically, flow velocity of blood is much higher in IJVs and much lower in deep cerebral veins. Because of these differences in flow velocity there are important measures Dr. Zamboni suggests recording during CCSVI screening.
These include: 1) blocked flow or absence of flow in UR and supine position 2) measurements of flow direction assessed at 3 specific points on the neck 3) cross-sectional measurements in thyroid area 4) Doppler “B-mode” anomalies and stenoses of IJVs lumens and/or walls. Dr. Zamboni went on to explain his 5 Criteria for assessing the presence of CCSVI. Criterion #1 is the presence of reflux >1.5 sec assessed during a short period of apnea following a normal exhalation. Reflux is never assessed in a forced condition such as the Valsalva maneuver. Reflux is not a “wave” coming from the chest; rather, it is a reverse flow per Dr. Zamboni. He references “Venous Collateral Ciruclation of the Extracranial Cerebrospianl Outflow” in Curr Neurovasc Res 2009, Aug 6(3) 204-12 Review.
Dr. Zamboni describes Criterion #2 as detection of reflux in the deep cerebral veins or sinuses, as viewed through the peri-auricular window. He states that mono-directional flow toward the straight sinus characterized by low velocity and RI is appropriate. Any Doppler sampling at this location of deep cerebral veins that differs from this description is considered positive for Criterion #2. He also suggests using a new method of detecting DCV flow by viewing through the condylar window in front of the ear utilizing a specialized device (QDP) which is capable of making directional flow assessment easier. Dr. Zamboni’s Criterion #3 is the pressure of blocked outflow in IJVs and VVs in both UR and supine position. Mostly, intraluminal defects, malformed valves and septal webs. Criterion #4 is described as flow not Doppler detectable in the IJVs and/or Vertebral Veins (VV) in both UR and supine positions.
Criterion #5 is a cross-sectional area of IJVs in UR and supine positions. The CSA of IJVs in supine position should be greater than in the UR position, however, there can be a paradoxical inversion of proportion causing the CSA to be larger in UR position. Criterion #5 is positive if UR > supine CSA.
Echo Color Doppler using 5 Criteria as described by Dr. Zamboni for CCSVI in MS patients is an ideal screening tool. By using the 5 Criteria, CCSVI prevalence in MS is reported to be: 56% in US patients, 84% in Middle Orient, 91% in Central Europe and up to 100% in Italy (Neurology 2011, JNNP 2009, NeurSci 2009, Int Angio 2010). However they were not scanned at the junction of IJV—using other protocols CCSVI cannot be properly identified (AnnNeur 2010).
It was helpful to actually hear Dr. Zamboni explain his 5 Criteria and his understanding of venous anatomy and physiology. Patients need to educate themselves regarding these criteria and the proper methods of Doppler evaluation prior to seeking testing for CCSVI. It appears that patient positioning in both upright and supine positions is key to proper testing. Also, Doppler evaluation using the 3 locations on the neck, as described by Dr. Zamboni, is equally as important. Instrument positioning for Doppler evaluation in evaluating the deep cerebral veins is, apparently, challenging as well and requires training in order to accomplish.
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