The Experts below are selected from a list of 3021 Experts worldwide ranked by ideXlab platform
David Sarraf - One of the best experts on this subject based on the ideXlab platform.
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paracentral acute middle maculopathy and the Ischemic Cascade towards interventional management short title paracentral acute middle maculopathy
American Journal of Ophthalmology, 2021Co-Authors: Peter Y Zhao, Mark W Johnson, Richard H Mcdonald, David SarrafAbstract:Abstract Purpose To present select cases of paracentral acute middle maculopathy (PAMM) demonstrating progressive vascular occlusion and the Ischemic Cascade, and illustrate scenarios in which therapeutic intervention may be considered. Design Perspective. Methods Review and interpretation of selected literature, with perspective on the evaluation and management of patients with PAMM lesions. Multimodal imaging, including cross sectional and en face optical coherence tomography (OCT), of three illustrative cases of PAMM are presented, with progressive vascular occlusion and evidence of the Ischemic Cascade noted in two of the cases. Results All three cases showed evidence of PAMM at baseline, including perivenular PAMM in two of the cases. Progression from a mild central retinal vein occlusion (CRVO) to a more severe CRVO was noted in the first case, while the second case progressed from an incomplete to complete central retinal artery occlusion. In the third case, there was resolution of PAMM lesions associated with partial CRAO after the patient was started on aspirin. Conclusions Perivenular PAMM can be the only presenting sign of retinal vascular occlusion. In such cases it is important to differentiate between partial CRVO and incomplete CRAO as the underlying cause. This Perspective provides guidance on making this important distinction, which plays a critical role in directing the nature and urgency of the systemic work up. In patients with PAMM caused by partial retinal arterial occlusion, a benign empirical approach such as low-dose aspirin (81 mg) may be reasonable to reduce the likelihood of subsequent vision loss from progression to complete arterial occlusion. A clinical trial, however, is necessary to support such a strategy.
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pamm and the Ischemic Cascade associated with radiation retinopathy
American Journal of Ophthalmology Case Reports, 2020Co-Authors: Derrick Wang, Jay S. Duker, David SarrafAbstract:Abstract Purpose To report a case of paracentral acute middle maculopathy (PAMM) and evidence of the Ischemic Cascade documented with spectral domain optical coherence tomography (SD-OCT) following radiation treatment of a choroidal melanoma. Observations A healthy young patient was evaluated for an asymptomatic choroidal nevus in the left eye. Fundus examination was remarkable for a choroidal melanocytic lesion that measured 1.8 mm in thickness by initial B-scan ultrasound. Clinical examination 6 months later showed growth of the tumor at several margins with new subretinal fluid, and a B-scan measured thickness of 1.9 mm. The lesion was diagnosed as a small choroidal melanoma and treated with gamma knife radiation with a dose of 3000 cGy. Sixteen months later, examination showed signs of radiation retinopathy including cotton wool spots and PAMM via SD-OCT and OCT angiography and evidence of the Ischemic Cascade i.e. alternating zones of middle and combined middle and inner retinal layer infarction. Conclusions and Importance: Radiation retinopathy can include signs of microvascular damage and ischemia including lesions such as cotton wool spots and PAMM. A case is presented in this report of radiation retinopathy with OCT evidence of PAMM and the Ischemic Cascade.
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Paracentral Acute Middle Maculopathy and the Ischemic Cascade Associated With Retinal Vascular Occlusion.
American journal of ophthalmology, 2018Co-Authors: Mathieu F. Bakhoum, K. Bailey Freund, Rosa Dolz-marco, Belinda C. S. Leong, Caroline R. Baumal, Jay S. Duker, David SarrafAbstract:Purpose To analyze the spectrum of ischemia associated with paracentral acute middle maculopathy (PAMM) in eyes with acute retinal vascular occlusion and to describe an Ischemic Cascade. Design A retrospective observational case series. Methods Patients presenting with PAMM secondary to acute retinal vascular occlusion were identified. Analysis of multimodal imaging was performed at baseline and at follow-up visits to elucidate the patterns and progression of ischemia within the retinal layers. Results Multimodal retinal imaging from 16 eyes of 16 patients with acute retinal vascular occlusion associated with PAMM was studied. Analysis of en face optical coherence tomography (OCT) segmentation of the inner nuclear layer (INL) identified distinct patterns of PAMM correlating with the severity of ischemia and not the type of occlusion. A perivenular fern-like PAMM pattern was associated with better visual outcomes (average final visual acuity was 20/25). This pattern was noted to sequentially progress in 2 cases to a diffuse globular PAMM pattern in the INL, or to a pattern of ischemia involving both the middle and inner retinal layers with commensurate vision loss. Globular patterns of PAMM or ischemia involving both the middle and inner retina correlated with poorer visual outcomes (average final visual acuity was counting fingers at 5.5 ft). These various patterns of ischemia developed in eyes with retinal vascular occlusions in which blood flow through the retinal capillary plexuses was present but was significantly reduced and delayed. Conclusions This study describes OCT findings suggestive of an Ischemic Cascade in eyes with retinal vascular occlusion. The middle retina at the level of the deep capillary plexus, especially at the venular pole, may be more vulnerable to Ischemic injury.
Peter Y Zhao - One of the best experts on this subject based on the ideXlab platform.
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paracentral acute middle maculopathy and the Ischemic Cascade towards interventional management short title paracentral acute middle maculopathy
American Journal of Ophthalmology, 2021Co-Authors: Peter Y Zhao, Mark W Johnson, Richard H Mcdonald, David SarrafAbstract:Abstract Purpose To present select cases of paracentral acute middle maculopathy (PAMM) demonstrating progressive vascular occlusion and the Ischemic Cascade, and illustrate scenarios in which therapeutic intervention may be considered. Design Perspective. Methods Review and interpretation of selected literature, with perspective on the evaluation and management of patients with PAMM lesions. Multimodal imaging, including cross sectional and en face optical coherence tomography (OCT), of three illustrative cases of PAMM are presented, with progressive vascular occlusion and evidence of the Ischemic Cascade noted in two of the cases. Results All three cases showed evidence of PAMM at baseline, including perivenular PAMM in two of the cases. Progression from a mild central retinal vein occlusion (CRVO) to a more severe CRVO was noted in the first case, while the second case progressed from an incomplete to complete central retinal artery occlusion. In the third case, there was resolution of PAMM lesions associated with partial CRAO after the patient was started on aspirin. Conclusions Perivenular PAMM can be the only presenting sign of retinal vascular occlusion. In such cases it is important to differentiate between partial CRVO and incomplete CRAO as the underlying cause. This Perspective provides guidance on making this important distinction, which plays a critical role in directing the nature and urgency of the systemic work up. In patients with PAMM caused by partial retinal arterial occlusion, a benign empirical approach such as low-dose aspirin (81 mg) may be reasonable to reduce the likelihood of subsequent vision loss from progression to complete arterial occlusion. A clinical trial, however, is necessary to support such a strategy.
J C Grotta - One of the best experts on this subject based on the ideXlab platform.
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neuroprotection and the Ischemic Cascade
Cns Spectrums, 2000Co-Authors: Robert A Felberg, W S Burgin, J C GrottaAbstract:Brain ischemia is a process of delayed neuronal cell death, not an instantaneous event. The concept of neuroprotection is based on this principle. Diminished cerebral blood flow initiates a series of events (the "Ischemic Cascade") that lead to cell destruction. This Ischemic Cascade is akin to a spreading epidemic starting from a hypothesized core of ischemia and radiating outward. If intervention occurs early, the process may be halted. Interventions have been directed toward salvaging the Ischemic penumbra. Hypothermia decreases the size of the Ischemic insult in both anecdotal clinical and laboratory reports. In addition, a wide variety of agents have been shown to reduce infarct volume in animal models. Pharmacologic interventions that involve thrombolysis, calcium channel blockade, and cell membrane receptor antagonism have been studied and have been found to be beneficial in animal cortical stroke models. Human trials of neuroprotective therapies have been disappointing. Other than thrombolytics, no agents have shown an unequivocal benefit. The future of neuroprotection will require a logical extension of what has been learned in the laboratory and previous human trials. A sensible approach to the use of multiple-agent cocktails used in combination with thrombolytics is likely to offer the highest chance for benefit.
Jose Melena - One of the best experts on this subject based on the ideXlab platform.
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retinal ischemia mechanisms of damage and potential therapeutic strategies
Progress in Retinal and Eye Research, 2004Co-Authors: Neville N Osborne, Robert J Casson, J P M Wood, G Chidlow, Mark Graham, Jose MelenaAbstract:Retinal ischemia is a common cause of visual impairment and blindness. At the cellular level, Ischemic retinal injury consists of a self-reinforcing destructive Cascade involving neuronal depolarisation, calcium influx and oxidative stress initiated by energy failure and increased glutamatergic stimulation. There is a cell-specific sensitivity to Ischemic injury which may reflect variability in the balance of excitatory and inhibitory neurotransmitter receptors on a given cell. A number of animal models and analytical techniques have been used to study retinal ischemia, and an increasing number of treatments have been shown to interrupt the "Ischemic Cascade" and attenuate the detrimental effects of retinal ischemia. Thus far, however, success in the laboratory has not been translated to the clinic. Difficulties with the route of administration, dosage, and adverse effects may render certain experimental treatments clinically unusable. Furthermore, neuroprotection-based treatment strategies for stroke have so far been disappointing. However, compared to the brain, the retina exhibits a remarkable natural resistance to Ischemic injury, which may reflect its peculiar metabolism and unique environment. Given the increasing understanding of the events involved in Ischemic neuronal injury it is hoped that clinically effective treatments for retinal ischemia will soon be available.
Mathieu F. Bakhoum - One of the best experts on this subject based on the ideXlab platform.
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Paracentral Acute Middle Maculopathy and the Ischemic Cascade Associated With Retinal Vascular Occlusion.
American journal of ophthalmology, 2018Co-Authors: Mathieu F. Bakhoum, K. Bailey Freund, Rosa Dolz-marco, Belinda C. S. Leong, Caroline R. Baumal, Jay S. Duker, David SarrafAbstract:Purpose To analyze the spectrum of ischemia associated with paracentral acute middle maculopathy (PAMM) in eyes with acute retinal vascular occlusion and to describe an Ischemic Cascade. Design A retrospective observational case series. Methods Patients presenting with PAMM secondary to acute retinal vascular occlusion were identified. Analysis of multimodal imaging was performed at baseline and at follow-up visits to elucidate the patterns and progression of ischemia within the retinal layers. Results Multimodal retinal imaging from 16 eyes of 16 patients with acute retinal vascular occlusion associated with PAMM was studied. Analysis of en face optical coherence tomography (OCT) segmentation of the inner nuclear layer (INL) identified distinct patterns of PAMM correlating with the severity of ischemia and not the type of occlusion. A perivenular fern-like PAMM pattern was associated with better visual outcomes (average final visual acuity was 20/25). This pattern was noted to sequentially progress in 2 cases to a diffuse globular PAMM pattern in the INL, or to a pattern of ischemia involving both the middle and inner retinal layers with commensurate vision loss. Globular patterns of PAMM or ischemia involving both the middle and inner retina correlated with poorer visual outcomes (average final visual acuity was counting fingers at 5.5 ft). These various patterns of ischemia developed in eyes with retinal vascular occlusions in which blood flow through the retinal capillary plexuses was present but was significantly reduced and delayed. Conclusions This study describes OCT findings suggestive of an Ischemic Cascade in eyes with retinal vascular occlusion. The middle retina at the level of the deep capillary plexus, especially at the venular pole, may be more vulnerable to Ischemic injury.
