VASCULAR ARDMS RVT EXAM - INDIRECT TESTING FOR CEREBROVASCULAR SYSTEM 2023

What are the different types of indirect testing for cerebrovascular? OPG -GEE - Oculopneumoplethysmography, Preorbital Testing, TCD- Transcranial Doppler What are the indirect cerebrovascular testing used for? They are used to identify Hemodynamically significant lesion, HDSL ,of the Interal Carotid Artery by evaluating flow at some of its terminal branches. What are limitations of indirect cerebrovascular testing? - These types of exams cannot differentiate between a tight stenosis and an occlusion -These types of exams are only helpful if there is a HDSL, hemodynamically significant lesion present OPG- GEE - Oculopneumoplethysmography -this is an indirect test -provides information regarding Hemodynimcally signficant lesion (HDSL) in the Internal Carotid Artery What are limitations of Oculopneumoplethysmography? -Cannot determine the exact location of the stenosis -Cannot determine between tight stenosis and an occlusion -Not helpful when well developed collateral pathways exists -Not helpful in monitoring the progression of disease What are the contraindications and reasons not to perform oculopneumoplethysmography exam? Patient with glauecoma Patient with allergies to local anesthetics Patient with a history of retinal detachment Patient whom have had eye surgery in the past 6 months Method of OPG-GEE , Oculopneumoplethysmography Patient is supine Take brachial blood pressure If blood pressure is less than 140 mmHg, then use a vaccum of 300mmHg If blood pressure is greater than 140mmHg, then use a vaccum of 500mmHg A local anesthetic is applied to the eye Eye cups are placed on the eye and the correct amount of vaccum is applied to the cup This will obstruct blood flow in the arteries that supply blood to the eye The patient will lose vision for a short period of time The vaccum is released, and arterial flow into the eye returns, when the opthamlic artery pressure exceeds the intraoccular pressure. This pressure reflects the pressure in the Distal Internal Carotid Artery Results of OPG-GEE, Oculopneumoplethysmography -Ophthalmic systolic pressure should not differ by more than 5mmHg from left to right side -If the pressure difference exceeds 5mmHg, then the problem or disease is on the side with the lower pressure What is a normal ratio of ophthalmic systolic pressure (OSP) to Brachial systolic pressure (BSP) that should exist? OSP-39/BSP > 0.43 is normal -Ophthalmic systolic pressure minus 39 divided by brachial systolic pressure is greater than 0.43 is normal - if ratio is less than 0.43 , then there is disease Preorbital Testing -this is an indirect test that can evualuate the terminal branches of the Internal Carotid Artery What are limitations of Preorbital Testing? -Cannot differientiate between a tight stenosis and an occlusion -is not diagnostic if hemodynamically signficant lesion (HDSL) is not present , which is at least a Diameter reduction of 50% and an area reduction of 75% of the vessel lumen - this exam requires great skill