Risk of Blindness Among Patients With Diabetes and Newly Diagnosed Diabetic Retinopathy.

OBJECTIVE: To evaluate the association between initial diabetic retinopathy (DR) severity/risk of blindness in patients with newly diagnosed DR/good vision in the U.S. RESEARCH DESIGN AND METHODS: This retrospective cohort study evaluated adult patients with good vision (20/40 or better) and newly diagnosed DR between 1 January 2013 and 31 December 2017 (index date) in the American Academy of Ophthalmology's Intelligent Research in Sight (IRIS) Registry. The primary exposure of interest was DR severity at index: mild nonproliferative DR (NPDR), moderate NPDR, severe NPDR, and proliferative DR (PDR). The main outcome measure was development of sustained blindness (SB), defined as study eyes with Snellen visual acuity readings of 20/200 or worse at two separate visits ≥3 months apart that did not improve beyond 20/100. RESULTS: Among 53,535 eligible eyes (mean follow-up 662.5 days), 678 (1.3%) eyes developed SB. Eyes with PDR at index represented 10.5% (5,629 of 53,535) of the analysis population but made up 26.5% (180 of 678) of eyes that developed SB. Kaplan-Meier analysis revealed that eyes with moderate NPDR, severe NPDR, and PDR at index were 2.6, 3.6, and 4.0 times more likely, respectively, to develop SB after 2 years of DR diagnosis versus eyes with mild DR at index. In a Cox proportional hazards model adjusted for index characteristics/development of ocular conditions during follow-up, eyes with PDR had an increased risk of developing SB versus eyes with mild NPDR at index (hazard ratio 2.26 [95% CI 2.09-2.45]). CONCLUSIONS: In this longitudinal ophthalmologic registry population involving eyes with good vision, more advanced DR at first diagnosis was a significant risk factor for developing SB.

CT and MRI early vessel signs reflect clot composition in acute stroke.

BACKGROUND AND PURPOSE: The purpose of this study was to provide the first correlative study of the hyperdense middle cerebral artery sign (HMCAS) and gradient-echo MRI blooming artifact (BA) with pathology of retrieved thrombi in acute ischemic stroke. METHODS: Noncontrast CT and gradient-echo MRI studies before mechanical thrombectomy in 50 consecutive cases of acute middle cerebral artery ischemic stroke were reviewed blinded to clinical and pathology data. Occlusions retrieved by thrombectomy underwent histopathologic analysis, including automated quantitative and qualitative rating of proportion composed of red blood cells (RBCs), white blood cells, and fibrin on microscopy of sectioned thrombi. RESULTS: Among 50 patients, mean age was 66 years and 48% were female. Mean (SD) proportion was 61% (±21) fibrin, 34% (±21) RBCs, and 4% (±2) white blood cells. Of retrieved clots, 22 (44%) were fibrin-dominant, 13 (26%) RBC-dominant, and 15 (30%) mixed. HMCAS was identified in 10 of 20 middle cerebral artery stroke cases with CT with mean Hounsfield Unit density of 61 (±8 SD). BA occurred in 17 of 32 with gradient-echo MRI. HMCAS was more commonly seen with RBC-dominant and mixed than fibrin-dominant clots (100% versus 67% versus 20%, P=0.016). Mean percent RBC composition was higher in clots associated with HMCAS (47% versus 22%, P=0.016). BA was more common in RBC-dominant and mixed clots compared with fibrin-dominant clots (100% versus 63% versus 25%, P=0.002). Mean percent RBC was greater with BA (42% versus 23%, P=0.011). CONCLUSIONS: CT HMCAS and gradient-echo MRI BA reflect pathology of occlusive thrombus. RBC content determines appearance of HMCAS and BA, whereas absence of HMCAS or BA may indicate fibrin-predominant occlusive thrombi.

Analysis of thrombi retrieved from cerebral arteries of patients with acute ischemic stroke.

BACKGROUND AND PURPOSE: Information regarding the histological structure of thromboemboli that cause acute stroke provides insight into pathogenesis and clinical management. METHODS: This report describes the histological analysis of thromboemboli retrieved by endovascular mechanical extraction from the middle cerebral artery (MCA) and intracranial carotid artery (ICA) of 25 patients with acute ischemic stroke. RESULTS: The large majority (75%) of thromboemboli shared architectural features of random fibrin:platelet deposits interspersed with linear collections of nucleated cells (monocytes and neutrophils) and confined erythrocyte-rich regions. This histology was prevalent with both cardioembolic and atherosclerotic sources of embolism. "Red" clots composed uniquely of erythrocytes were uncommon and observed only with incomplete extractions, and cholesterol crystals were notably absent. The histology of thromboemboli that could not be retrieved from 29 concurrent patients may be different. No thrombus >3 mm wide caused stroke limited to the MCA, and no thrombus >5 mm wide was removed from the ICA. A mycotic embolus was successfully removed in 1 case, and a small atheroma and attached intima were removed without clinical consequence from another. CONCLUSIONS: Thromboemboli retrieved from the MCA or intracranial ICA of patients with acute ischemic stroke have similar histological components, whether derived from cardiac or arterial sources. Embolus size determines ultimate destination, those >5 mm wide likely bypassing the cerebral vessels entirely. The fibrin:platelet pattern that dominates thromboembolic structure provides a foundation for both antiplatelet and anticoagulant treatment strategies in stroke prevention.