Latest / Glaucoma, Vision & Longevity: Supplements & Science / Carotid-Cavernous Fistula and Glaucoma: Venous Hypertension at the Eye

Transcript

Carotid-Cavernous Fistula and Glaucoma: Venous Hypertension at the Eye · Glaucoma, Vision & Longevity: Supplements & Science

• 0:00
  SPEAKER_00: Carotid cavernous fistulas and eye pressure.
• 0:03
  SPEAKER_00: Carotid cavernous fistulas are abnormal connections between an artery and the venous cavernous sinus at the base of the skull.
• 0:12
  SPEAKER_00: In simple terms, blood that should flow through arteries is shunted directly into veins.
• 0:17
  SPEAKER_00: This raises the blood pressure inside the eye's venous system.
• 0:21
  SPEAKER_00: The extra pressure backs up into the veins around the eye, raising the episcral venous pressure, the pressure in veins near the surface of the eyeball.
• 0:29
  SPEAKER_00: When this happens, the eye's fluid outflow is blocked and intraocular pressure, IOP rises, potentially causing secondary glaucoma.
• 0:38
  SPEAKER_00: Early signs of a CCF can include a red, swollen eye, a bulging eyeball, proptosis, a noise like a whoosh in the head brute, and vision changes.
• 0:47
  SPEAKER_00: These findings result from venous hypertension, high pressure in the eye's veins.
• 0:52
  SPEAKER_00: Because of the slow, high-pressure blood flow, the normally thin conjunctival veins become arterialized, bright red, and corkscrew-shaped.
• 1:01
  SPEAKER_00: Patients may also have chemosis, conjunctival swelling, and double vision if eye movement nerves are affected.
• 1:08
  SPEAKER_00: Knowing these symptoms helps prompt imaging and treatment, which can quickly lower eye pressure and protect vision.
• 1:15
  SPEAKER_00: How CCFs raise eye pressure.
• 1:18
  SPEAKER_00: There are two main types of carotid cavernous fistulas and both create orbital venous hypertension.
• 1:24
  SPEAKER_00: Direct CCFs, barotype A, occur when the main internal carotid artery tears directly into the cavernous sinus.
• 1:31
  SPEAKER_00: This usually happens in trauma, head injury, or skull fracture, or rarely from a ruptured aneurysm.
• 1:37
  SPEAKER_00: Because the tear is large, these fistulas are high flow.
• 1:40
  SPEAKER_00: A huge wave of arterial blood rushes into the venous cavernous sinus and then retrogrades, flows backward into the eye's veins.
• 1:48
  SPEAKER_00: Indirect or dural CCFs, types B, C, D, involve small meningal branches of the carotid or external carotid arteries feeding the sinus.
• 1:57
  SPEAKER_00: These connections are smaller and low flow, often developing spontaneously in older adults.
• 2:03
  SPEAKER_00: Even though dural CCFs are lower flow, they still raise sinus pressure over time.
• 2:09
  SPEAKER_00: In both cases, the key is that arterial blood at high pressure enters the cavernous sinus, crowding out normal venous flow.
• 2:16
  SPEAKER_00: This creates venous stasis and back pressure.
• 2:18
  SPEAKER_00: The superior ophthalmic vein, and sometimes inferior ophthalmic vein, carries blood from the eye to the cavernous sinus.
• 2:26
  SPEAKER_00: When the cavernous sinus pressure climbs above the pressure in those veins, flow reverses or stalls.
• 2:33
  SPEAKER_00: These veins become engorged, and the normal balance of fluid in the eye is disturbed.
• 2:38
  SPEAKER_00: The eye constantly produces watery fluid, aqueous humor, and normally this drains out through veins.
• 2:44
  SPEAKER_00: If the veins are jammed by high pressure, the fluid cannot drain, and the eye pressure rises to match the venous pressure.
• 2:52
  SPEAKER_00: The normal episcleral venous pressure is only about 8 to 10 millimeter hergrangs.
• 2:57
  SPEAKER_00: In a CCF, that pressure can jump much higher.
• 3:00
  SPEAKER_00: Once the episcleral pressure reaches the level of the IOP, any further increase in venous pressure forces the IOP to rise almost equally.
• 3:08
  SPEAKER_00: In practical terms, every extra mimimeter grams of pressure in the eye's veins directly adds to the eye's internal pressure.
• 3:15
  SPEAKER_00: As a result, patients with CCF often develop a secondary open-angle glaucoma where fluid cannot exit because of the high back pressure.
• 3:24
  SPEAKER_00: Note, in rare cases, the raised pressure can also push the iris forward, shallowing the front chamber and causing angle closure glaucoma or cause poor retinal blood flow and new troublesome vessels.
• 3:36
  SPEAKER_00: But most CCF-related glaucoma is from the simple effect of blocked venous outflow.
• 3:42
  SPEAKER_00: Recognizing the key eye findings.
• 3:45
  SPEAKER_00: When a carotid cavernous fistula develops, it often creates striking eye signs.
• 3:50
  SPEAKER_00: One of the hallmarks is arterialized conjunctival vessels.
• 3:53
  SPEAKER_00: Normally, the white of the eye has fine red veins.
• 3:56
  SPEAKER_00: In CCF, those veins look bright red, engorged, and tortuous, often described as corkscrew vessels, because they carry direct arterial blood.
• 4:05
  SPEAKER_00: Patients usually have conjunctival chemosis, swelling of the clear membrane, conjunctiva, covering the white of the eye, causing a bloodshot, puffy appearance.
• 4:16
  SPEAKER_00: Another classic feature is proptosis, bulging of the eyeball.
• 4:20
  SPEAKER_00: Because the venous congestion extends behind the eye, the eye can protrude forward, and in a high-flow fistula, it may even pulsate in time with the heartbeat.
• 4:30
  SPEAKER_00: Eye movement can become limited too, and patients often develop double vision, diplopia, if the cranial nerves or engorged eye muscles are affected.
• 4:40
  SPEAKER_00: There may also be ptosis, drooping eyelid, or an enlarged pupil on that side if the nerves in the sinus are involved.
• 4:47
  SPEAKER_00: A very important clue is the orbital brute.
• 4:50
  SPEAKER_00: This is an abnormal whooshing or throbbing sound heard by placing a stethoscope over the eye or temple.
• 4:56
  SPEAKER_00: High flow fistulas typically create an audible brute synchronous with the heartbeat.
• 5:01
  SPEAKER_00: Even low-flow fistulas can sometimes produce a subtle brute, especially during valsalva, holding breath or straining.
• 5:08
  SPEAKER_00: Finally, and often most importantly, the affected eye shows elevated intraocular pressure, IOP.
• 5:14
  SPEAKER_00: As the episodes of venous hypertension progress, the IOP may climb significantly, we have seen cases over 30 millimeter curms.
• 5:23
  SPEAKER_00: Ophthalmologists will notice an engorged episcleral venous plexus on exam, often with blood visible in Schlem's canal, the eye's drainage channel.
• 5:31
  SPEAKER_00: A standard applanation tonometry test may even show wobbly blinking tendometer mires reflecting the pulsatility of the eye.
• 5:38
  SPEAKER_00: In one report, more than 64% of patients with CCF had high IOP, 22 to 55 millimeter hergrams.
• 5:46
  SPEAKER_00: In short, a swollen red pulsating eye with corkscrew vessels and a brute should immediately raise concern for a fistula.
• 5:53
  SPEAKER_00: Imaging the fistula and eyes.
• 5:55
  SPEAKER_00: If a CCF is suspected from the eye exam, imaging is the next step.
• 6:00
  SPEAKER_00: Several tests can pick up clues, CT or MR, angiography.
• 6:04
  SPEAKER_00: These non-invasive scans of brain vessels can show an enlarged cavernous sinus, a dilated superior ophthalmic vein, or early filling of the venous system.
• 6:13
  SPEAKER_00: They often suggest a fistula and can guide planning.
• 6:16
  SPEAKER_00: Ultrasound with Doppler, a skilled sonographer, can sometimes detect reversed blood flow in an orbital vein or a color brute of turbulent flow.
• 6:24
  SPEAKER_00: Eye ultrasound may show an enlarged or pulsating ophthalmic vein.
• 6:28
  SPEAKER_00: Gadolinium-enhanced MRI MRA can reveal enlargement and abnormal flow voids in the orbit and cavernous sinus.
• 6:36
  SPEAKER_00: However, the gold standard for diagnosis and exact classification is digital subtraction catheter angiography, DSA.
• 6:43
  SPEAKER_00: This is an invasive X-ray test where contrast dye is injected into the carotid and other arteries under fluoroscopy.
• 6:51
  SPEAKER_00: Angiography precisely shows the location, size, and type of fistula, and whether it is draining anteriorly to the eye or posteriorly to the brain.
• 7:00
  SPEAKER_00: For example, angiography will diagnose a barrow type A versus D fistula and show if the superior ophthalmic vein is filling backward.
• 7:08
  SPEAKER_00: It also allows measurement of flow.
• 7:10
  SPEAKER_00: In practice, ophthalmologists often first order a CTA or MRA if suspicious, then confirm with angiography.
• 7:18
  SPEAKER_00: Endovascular treatment and IOP effects.
• 7:21
  SPEAKER_00: Management of a CCF usually involves an interventional radiologist or neurosurgeon working with the eye doctor.
• 7:27
  SPEAKER_00: The main goal is to occlude block the fistula, stopping the abnormal blood flow and restoring normal venous drainage.
• 7:34
  SPEAKER_00: In direct type A fistulas, treatment is usually urgent.
• 7:38
  SPEAKER_00: A catheter is threaded through the femoral or carotid artery to the cavernous sinus, and the connection is closed off with coils, balloons, or liquid embolic agents.
• 7:48
  SPEAKER_00: Modern detachable balloons or platinum coils conceal the tear in the artery.
• 7:52
  SPEAKER_00: Sometimes a stent or liquid glue, onyx, is used.
• 7:56
  SPEAKER_00: Heidelberg et al.
• 7:57
  SPEAKER_00: reported using a detachable balloon in a direct CCF.
• 8:01
  SPEAKER_00: In dural indirect fistulas types BD, the decision to treat depends on symptoms.
• 8:06
  SPEAKER_00: Because these are low flow, some will spontaneously close or remain asymptomatic.
• 8:11
  SPEAKER_00: If eye pressure is high or vision is threatened, treatment is indicated.
• 8:16
  SPEAKER_00: The embolization may go through arterial feeders or more commonly, a transvenous approach via the venous system through the inferior petrosol sinus or rarely via a cutdown on the superior ophthalmic vein.
• 8:28
  SPEAKER_00: The goal is to deliver coils or liquid to the cavernous sinus to plug the fistula from the vein side.
• 8:34
  SPEAKER_00: These endovascular procedures have become highly effective and relatively safe.
• 8:40
  SPEAKER_00: After the fistula is closed, venous pressure in the orbit drops and the eye congestion resolves.
• 8:46
  SPEAKER_00: Notably, intraocular pressure often falls quickly.
• 8:49
  SPEAKER_00: Case reports and series document dramatic IOP improvement after successful embolization.
• 8:55
  SPEAKER_00: For instance, in one case, IOP in one eye dropped from 34 mm to 19 mm just one week after CCF closure.
• 9:03
  SPEAKER_00: Another study found that embolization lowered the patient's IOP by about 9 mm on average.
• 9:08
  SPEAKER_00: In that report, after angiographic occlusion of a bilateral CCF, both eyes' pressures fell from the mid-20s into the high teens.
• 9:17
  SPEAKER_00: This confirms that fixing the fistula is often the most powerful way to reduce eye pressure.
• 9:23
  SPEAKER_00: Adjunct medical therapy for glaucoma is usually given until the fistula is closed.
• 9:28
  SPEAKER_00: Patients may use combinations of eye drops, beta blockers, carbonic anhydrase inhibitors, prostaglandin analogues, and oral acetazolamide to help manage the pressure.
• 9:38
  SPEAKER_00: However, high episcleral venous pressure often blunts the effect of drops.
• 9:43
  SPEAKER_00: Once flow is normalized, the same medications become more effective at maintaining a normal pressure.
• 9:49
  SPEAKER_00: If embolization fails or only partially succeeds and IOP remains dangerously high, eye surgery may be needed.
• 9:56
  SPEAKER_00: Options include laser trabeculoplasty or filtering surgeries, trabeculectomy, shunts.
• 10:02
  SPEAKER_00: Recent reports note that glaucoma drainage devices, tube shunts, can be life-saving.
• 10:07
  SPEAKER_00: In one case of indirect CCF, where embolization was incomplete, implanting an Ahmed valve finally normalized the pressure.
• 10:15
  SPEAKER_00: However, most experts attempt fistula closure first whenever possible, because that often solves the glaucoma root cause.
• 10:23
  SPEAKER_00: Balancing eye treatment versus fistula closure.
• 10:26
  SPEAKER_00: Deciding when to treat the eye pressure versus the fistula depends on urgency and feasibility.
• 10:32
  SPEAKER_00: Generally, if the patient can safely wait a short time, the priority is to close the fistula, because doing so treats the underlying cause of high IOP.
• 10:41
  SPEAKER_00: In one report, authors emphasized that transluminal occlusion of the fistula should be done before any glaucoma surgery.
• 10:48
  SPEAKER_00: After closure, they saw enough pressure drop that more invasive eye surgery was often avoided.
• 10:54
  SPEAKER_00: Indeed, many cases show substantial IOP reduction immediately after successful embolization.
• 11:00
  SPEAKER_00: However, if the eye pressure is extremely high or the patient has severe vision loss, simultaneous measures are needed.
• 11:08
  SPEAKER_00: For example, if optic nerve damage is imminent, an ophthalmologist may place a drainage shunt or perform laser trabeculoplasty while planning the fistula embolization.
• 11:18
  SPEAKER_00: Medications and even laser peripheral iridotomy can be performed to reduce IOP temporarily.
• 11:25
  SPEAKER_00: In practice, doctors will manage the glaucoma medically as best they can until the fistula is closed.
• 11:30
  SPEAKER_00: As Heichel et al.
• 11:32
  SPEAKER_00: put it, closing the fistula should be considered before planning any glaucoma surgery, whenever feasible.
• 11:38
  SPEAKER_00: Here are two illustrative cases.
• 11:40
  SPEAKER_00: Case 1, a 73-year-old woman had long-standing mild glaucoma, then developed new bulging eyes, double vision, and a red left eye.
• 11:48
  SPEAKER_00: Her untreated IOP shot up above 30 millimeter Hergrogs.
• 11:52
  SPEAKER_00: Imaging, MR angiography found a direct CCF.
• 11:55
  SPEAKER_00: After transarterial coil embolization of the fistula, her chemosis and proptosis largely resolved, and IOP quickly fell into the teens on modest medication.
• 12:05
  SPEAKER_00: This case shows how closing the fistula normalized orbital pressure and improved glaucoma control.
• 12:11
  SPEAKER_00: Case 2, a 48-year-old woman presented with a red proptotic eye and very high IOP in that eye, mid-40s, initially thought to be inflammation.
• 12:20
  SPEAKER_00: Angiography revealed a dural type D CCF.
• 12:24
  SPEAKER_00: Endovascular embolization achieved only near-complete closure.
• 12:27
  SPEAKER_00: Although venous congestion improved, her eye pressure remained elevated despite drops.
• 12:32
  SPEAKER_00: Further embolization attempts failed, so the team implanted an Ahmed glaucoma valve shunt in the affected eye.
• 12:39
  SPEAKER_00: After the tube surgery, her IOP dropped into the normal range.
• 12:43
  SPEAKER_00: This example underscores that if embolization can't fully fix the pressure issue, glaucoma surgery is the necessary backup.
• 12:51
  SPEAKER_00: In summary, most experts agree on a multidisciplinary approach.
• 12:55
  SPEAKER_00: Ophthalmologists should treat the eye to protect vision, drops, laser, while neuroradiologists or neurosurgeons plan embolization.
• 13:03
  SPEAKER_00: When possible, the fistula is treated first, which often eases or cures the glaucoma.
• 13:08
  SPEAKER_00: When fistula closure is difficult or delayed, targeted glaucoma surgery can stabilize the eye.
• 13:15
  SPEAKER_00: Conclusion: Carotid cavernous fistulas are an important and treatable cause of secondary glaucoma.
• 13:21
  SPEAKER_00: By shunting high-pressure blood into the cavernous sinus, they raise orbital venous pressure and episcleral pressure, leading to eye redness, proptosis, and markedly elevated intraocular pressure.
• 13:32
  SPEAKER_00: Recognizing the signs, corkscrew conjunctival veins, chemosis, brute, and a pulsating eye is crucial for prompt diagnosis.
• 13:41
  SPEAKER_00: Non-invasive imaging, CTA-MRA, followed by angiography, confirms the diagnosis and guides treatment.
• 13:48
  SPEAKER_00: Modern endovascular therapy, balloons, etc., can usually close the fistula safely.
• 13:54
  SPEAKER_00: Closing the fistula tends to normalize eye pressure, often dramatically reducing the need for aggressive glaucoma surgery.
• 14:01
  SPEAKER_00: Patients with CCF require close collaboration between eye doctors and neurointerventionists, but with timely care, the outlook is good.
• 14:09
  SPEAKER_00: The ocular venous congestion can resolve and vision can often be preserved.
• 14:13
  SPEAKER_00: All links to sources are available in the text version of this article.
• 14:18
  SPEAKER_00: You can find the full article at VisualFieldTest.com.
• 14:21
  SPEAKER_00: Thanks for listening.
• 14:23
  SPEAKER_00: To check your visual field, click the link at the bottom of this article or visit visualfieldtest.com.