Cerebral arteriovenous fistulae

Retinal arterial-venous pulse delay: a new specific marker for a carotid-cavernous fistula

Purpose

The purpose of the study was to describe ocular blood flow changes in eyes affected by a carotid-cavernous fistula (CCF) using laser speckle flowgraphy. We hypothesized that imaging blood flow velocity waveforms in the retinal arterioles and venules simultaneously would reveal specific characteristics of an arteriovenous (AV) connection.

Design

The study was an observational case series, with a retrospective case-control analysis.

Methods

Five patients with a CCF underwent measurement of ocular blood flow using laser speckle flowgraphy. The blood flow was compared retrospectively between a control group of healthy subjects (n = 32) and patients with an elevated intraocular pressure or venous outflow impairment without an AV fistula (n = 40). The outcomes were derived from the arteriole and venule blood flow velocity waveforms, including an A-V phase delay and flow pulsatility.

Results

The presence of an active CCF was associated with an increased delay in the peak velocity measured in the retinal venule (10.7% ± 2.2% of the cardiac cycle duration) compared with unaffected fellow eyes (1.8% ± 0.2%; p = 0.05) or control eyes of normal subjects (2.7% ± 0.3%; p = 0.02). This delay disappeared after fistula thrombosis and was not present in eyes with a central retinal vein occlusion (CRVO), glaucoma, non-arteritic anterior ischemic optic neuropathy (NAION), or papilledema. The venule blood flow velocity decreased during systole (and in some cases momentarily stopped), leading to a delayed pulse with a greater amplitude in the venules than in fellow eyes and normal controls after normalizing to the arteriole amplitude (1.71 ± 0.3 vs 0.54 ± 0.03 vs 0.59 ± 0.02; p = 8.0E-12). This specific AV delay could also be identified in a scanning laser ophthalmoscope (SLO; SPECTRALIS®) video.

Conclusion

Laser speckle flowgraphy reveals dynamic retinal vascular changes in eyes affected by a CCF, which are not present in healthy controls or patients with other eye conditions, and which reverses with treatment.

A Microsurgical Arteriovenous Malformation Model on Saphenous Vessels in the Rat

Arteriovenous malformation (AVM) is an anomaly of blood vessel formation. Numerous models have been established to understand the nature of AVM. These models have limitations in terms of the diameter of the vessels used and the impact on the circulatory system. Our goal was to establish an AVM model that does not cause prompt and significant hemodynamic and cardiac alterations but is feasible for follow-up of the AVM's progression. Sixteen female rats were randomly divided into sham-operated and AVM groups. In the AVM group, the saphenous vein and artery were interconnected using microsurgical techniques. The animals were followed up for 12 weeks. Anastomosis patency and the structural and hemodynamic changes of the heart were monitored. The hearts and vessels were histologically analyzed. During the follow-up period, shunts remained unobstructed. Systolic, diastolic, mean arterial pressure, and heart rate values slightly and non-significantly decreased in the AVM group. Echocardiogram results indicated minor systolic function impact, with slight and insignificant changes in aortic pressure and blood velocity, and minimal left ventricular wall enlargement. The small-caliber saphenous AVM model does not cause acute hemodynamic changes. Moderate but progressive alterations and venous dilatation confirmed AVM-like features. The model seems to be suitable for studying further the progression, enlargement, or destabilization of AVM.

Bilateral cavernous sinus dural arteriovenous fistula with initial ocular symptom: A case report

RATIONALE

Cavernous sinus dural arteriovenous fistula (CSDAVF) is a rare intracranial vascular malformation. Because of its complicated clinical manifestations, it is easy to miss or misdiagnose CSDAVF.

PATIENT CONCERNS

A 42-year-old female had chief complaint that the right eyeball had conjunctival congestion for half a year. She was given levofloxacin eye drops to treat the right eye with anti-inflammatory treatment, but the symptoms did not improve. Cranial magnetic resonance and cerebrovascular imaging showed that the right lateral rectus muscle was slightly enlarged, the right eyeball was prominent, but there was no abnormality in the brain.

DIAGNOSES

Based on clinical and imaging examinations and digital subtraction angiography (DSA), she was diagnosed as low-flow CSDAVF.

INTERVENTIONS

The patient received interventional embolization with transvenous combined arterial approach using coils and Onyx liquid glue.

OUTCOMES

The patient's exophthalmos and congestion symptoms were improved.

CONCLUSION

DAS is the gold standard for the diagnose of CSDAVF. Intravascular embolization interventional therapy is an effective treatment for CSDAVF.