By Tamara T. Barghouthi, MD; Quang Vu, MD; Charles Tegeler, MD; Aarti Sarwal, MD
Reversed Robin Hood Syndrome (RRHS) is a condition seen in acute stroke and TIA patients with large vessel occlusions in which there is a paradoxical decrease in flow velocity in the affected vessel, distal to occlusion of the vessel, which can occur spontaneously or in response to vasodilatory stimuli (such as breath holding) and result in worsening or recurrence of stroke symptoms. This cerebral steal phenomenon was first described by Alexandrov et al in 2007. It is thought to be due to maximally dilated vessels in the ischemic territory that have impaired vasomotor reactivity. This causes blood to flow away from these vessels and into normal vessels, which have less resistance and the ability to autoregulate further dilate. We present two cases of RRHS discovered by transcranial dopplers (TCD).
Our first case is a 64-year-old man who reported recurrent episodes of amaurosis fugax in his left eye, expressive aphasia and dizzy spells that were triggered by tilting his head back and lifting his arms up. MRI brain demonstrated bilateral subcortical white matter lesions without acute infarcts. Computed Tomography Angiogram (CTA) head/neck with contrast demonstrated complete occlusion at the origin of the left common carotid artery (CCA) extending to the level of the carotid bifurcation. Digital subtraction angiography (DSA) demonstrated complete occlusion of the left CCA with no opacification of the left external carotid artery (ECA) or ICA from CCA injection. Additional findings suggested that the left hemisphere was predominantly supplied by the right ICA with cross-filling into the left hemisphere via a patent anterior communicating artery. TCD with vasoreactivity testing was subsequently performed as the patient continued to have symptoms. Vasomotor O2 reactivity was measured in the bilateral MCAs by breathing 5% CO2 via face mask. There was a borderline vasomotor response in the right MCA (30% increase, baseline/peak/post velocities: 33/43/33 cm/s, respectively). In contrast, the left MCA velocity decreased by 40% with CO2 (baseline/peak/post velocities: 25/15/26 cm/s, respectively). These findings are consistent with steal now classified as RRHS.
The second case involved a 69-year-old man who reported several months of worsening blurred and fading vision and presyncope whenever he looked up. DSA demonstrated chronic right ICA occlusion at the origin with retrograde flow to the right MCA through the ophthalmic artery and right posterior communicating artery. Additionally, there was 60% stenosis of the distal left ICA and complete occlusion of the left vertebral artery at the origin. TCD with vasoreactivity demonstrated a robust vasomotor response in the left MCA with CO2 (baseline/peak/post velocities: 20/32/23 cm/s, respectively). However, the velocity in the right MCA decreased by about 20% (baseline/peak/post velocities: 43/34/41 cm/s). As seen in the first case, this is consistent with RRHS.
These cases highlight the utility of TCD with vasoreactivity testing in assessing the cerebral hemodynamic state in those with recurrent or worsening stroke symptoms in the setting of large vessel occlusion. Many of these cases may be admitted to the neurocritical care unit due to fluctuating neurological symptoms. As illustrated in these cases, TCDs are able to provide valuable information regarding blood flow in real time which is not assessed by CTA and DSA. Identifying specific hemodynamic correlate causing worsening cerebral ischemia in RRHS can alter patient management by targeting blood pressure augmentation or identification of respiratory triggers of vasodilation, such as sleep apnea, hence changing the cerebrovascular management of such patients. This tool is useful in the neurological ICU setting because it is fast, noninvasive, can be easily repeated for comparisons and to see treatment effects and can influence critical time-dependent decision making.
- Alexandrov AV, Sharma VK, Lao AY, Tsivgoulis G, Malkoff MD, Alexandrov AW. Reversed Robin Hood syndrome in acute ischemic stroke patients. Stroke. 2007;38(11):3045-3048.
- Palazzo P, Balucani C, Barlinn K, et al. Association of reversed Robin Hood syndrome with risk of stroke recurrence. Neurology. 2010;75(22):2003-2008.