Calcific Emboli Research Articles

Calcified Basilar Artery Embolus With False-Patency Sign on Computed Tomography Angiogram.

Calcified Basilar Artery Embolus With False-Patency Sign on Computed Tomography Angiogram.

Pitfalls in the diagnosis of post‐TAVI (transcatheter aortic valve implantation) stroke

AbstractStroke is an infrequent yet well‐known complication of transcatheter aortic valve implantation (TAVI). While mechanical thrombectomy (MT) is a useful rescue procedure in patients with symptomatic post‐TAVI stroke, it should be reminded that embolic materials derived from degenerated aortic valve have heterogeneities. We describe a case of post‐TAVI stroke in which a calcified debris caused embolic occlusion of the left middle cerebral artery. The calcified embolus eluded detection on magnetic resonance imaging (MRI), which might have been responsible, at least in part, for unsuccessful MT. Formation of calcified debris may not be rare after TAVI, and therefore, brain CT may be given priority as an imaging modality in the initial evaluation of patients suspected of post‐TAVI stroke.

Abstract 9226: Stroke in Bicuspid Aortic Valve

Background: The bicuspid aortic valve (BAV) exhibits abnormal geometry and transvalvular flow and is susceptible to calcification with subsequent cardioembolic stroke from calcific embolic material. However, the description of embolic ischemic strokes in patients with BAV is limited to case reports. Methods: Consecutive patients from 1975-2015 with BAV (n=5401) at our institution were retrospectively identified. Patients with ischemic stroke before aortic valve replacement (AVR) were analyzed, and the stroke was characterized. Patients were grouped according to stroke etiology: calcific embolism from a BAV (BAV stroke); large artery atherosclerotic or lacunar stroke (LA stroke); and non-BAV, non-large artery embolic stroke (nLA stroke). Results: There were 83/5401 (1.5%) patients with ischemic stroke. Mean age was 54 ± 12 years and 28% were female. Stroke etiology was BAV stroke in 26/83 (31%), LA stroke in 23/83 (28%), nLA stroke in 30/83 (36%), and other in 4/83 (5%). Stroke was embolic in 72/83 (87%), as shown in Figure 1. CHA 2 DS 2 -VASc score was not different in patients with BAV stroke (1.4 ± 1.2) versus nLA stroke (1.8 ± 1.2, p=0.188) but was higher in LA stroke (2.3 ± 1.2, p=0.005 vs. BAV stroke). Recurrent stroke occurred in 41% overall (50% BAV stroke vs. 30% LA stroke vs. 47% nLA stroke, both p=NS vs. BAV stroke). BAV stroke was more commonly located in the retinal circulation (39% BAV stroke vs. 13% LA stroke [p=0.044] vs. 0% nLA stroke [p=0.002]). Patients with BAV and LA stroke were more likely to have moderate-to-severe aortic stenosis and undergo AVR sooner after stroke compared to patients with nLA stroke. Conclusions: Stroke is an important complication in patients with BAV. The most common type of stroke in BAV is embolic. Greater than one-third of embolic stroke resulted from embolism from a calcific aortic valve. Patients with BAV stroke commonly have a history of recurrent cerebral ischemic events, severe valvular disease, and proceed to AVR soon after stroke.

Fluorescein Angiography Detection of Combined Branch Retinal Vein and Artery Occlusion.

A77-year-old male with a history of diabetes mellitus, hypertension, chronic kidney disease, and hyperlipidemia presented for 1-month postoperative care following cataract extraction with a subjective complaint of a dark area in his left eye superior field. His uncorrected visual acuity measured 20/25 in each eye. The posterior ophthalmoscopic examination of the left eye revealed a large calcific embolus in the inferior retinal artery exiting the optic nerve (Fig. 1). The presence of moderate retinal hemorrhages consistent with diabetic and hypertensive retinopathy was evident.Figure 1: Color photograph showing large calcific embolus of the inferior retinal artery exiting the optic nerve.The fluorescein angiography study showed delayed filling of the inferior retinal artery in the arterial phase due to obstruction from an embolic vaso-occlusive event. The patient reported branch retinal artery occlusion symptoms, yet there were no acute ophthalmoscopic signs of venous occlusion. The collateral vein occlusion resulted from the proximity ofmechanical compression at the point of the shared arterial-venous adventitial sheath by the large embolus1 and was evident from the absent fluorescein filling within the inferior venous tributary (Fig. 2). Fluorescein angiography was of great diagnostic value to detect retinal non-perfusion from the combined branch retinal artery and vein occlusions, since the latter may have otherwise gone undiagnosed.Figure 2: Fluorescein angiography showing impaired inferior arterial filling and absent intermediate phase inferior venous circulation from embolic compression.

Benefit of mechanical thrombectomy in acute ischemic stroke related to calcified cerebral embolus

Summary purposeMechanical thrombectomies (MT) in patients with large vessel occlusion (LVO) related to calcified cerebral embolus (CCE) have been reported, through small case series, being associated with low reperfusion rate and worse outcome, compared to regular MT. The purpose of the MASC (Mechanical Thrombectomy in Acute Ischemic Stroke Related to Calcified Cerebral Embolus) study was to evaluate the incidence of CCEs treated by MT and the effectiveness of MT in this indication. MethodsThe MASC study is a retrospective multicentric (n = 37) national study gathering the cases of adult patients who underwent MT for acute ischemic stroke with LVO related to a CCE in France from January 2015 to November 2019. Reperfusion rate (mTICI ≥ 2B), complication rate and 90-day mRS were systematically collected. We then conducted a systematic review by searching for articles in PubMed, Cochrane Library, Embase and Google Scholar from January 2015 to March 2020. A meta-analysis was performed to estimate clinical outcome at 90 days, reperfusion rate and complications. ResultsWe gathered data from 35 patients. Reperfusion was obtained in 57% of the cases. Good clinical outcome was observed in 28% of the patients. The meta-analysis retrieved 136 patients. Reperfusion and good clinical outcome were obtained in 50% and 29% of the cases, respectively. ConclusionThe MASC study found worse angiographic and clinical outcomes compared to regular thrombectomies. Individual patient-based meta-analysis including the MASC findings shows a 50% reperfusion rate and a 29% of good clinical outcome.

Лечение эмболии ветви центральной артерии сетчатки при комбинированном аортальном стенозе в отдаленном послеоперационном периоде

Эмболия артерии сетчатки — известное возможное осложнение у пациентов с кальцинированным аортальным стенозом. Основой лечения окклюзий является восстановление кровотока. Высокая ассоциация с риском острых нарушений мозгового кровообращения, ограниченное время для оказания неотложной помощи, высокие риски при системном лечении, ухудшение качества зрения в перспективе являются особенностями данной группы пациентов. В работе представлен клинический случай эмболии нижней ветви центральной артерии сетчатки правого глаза у пациентки после кардиохирургического лечения комбинированного аортального порока с преобладанием выраженного стеноза и кальциноза. С учетом четкой визуализации кальцинированного эмбола в зоне окклюзии проведен лазерный эмболизис. Проходимость ветви центральной артерии сетчатки восстановлена частично из-за большого размера кальцинированного эмбола.

CT Angiography in Evaluating Large-Vessel Occlusion in Acute Anterior Circulation Ischemic Stroke: Factors Associated with Diagnostic Error in Clinical Practice.

It is currently not completely clear how well radiologists perform in evaluating large-vessel occlusion on CTA in acute ischemic stroke. The purpose of this study was to investigate potential factors associated with diagnostic error. Five hundred twenty consecutive patients with a clinical diagnosis of acute ischemic stroke (49.4% men; mean age, 72 years) who underwent CTA to evaluate large-vessel occlusion of the proximal anterior circulation were included. CTA scans were retrospectively reviewed by a consensus panel of 2 neuroradiologists. Logistic regression analysis was performed to investigate the association between several variables and missed large-vessel occlusion at the initial CTA interpretation. The prevalence of large-vessel occlusion was 16% (84/520 patients); 20% (17/84) of large-vessel occlusions were missed at the initial CTA evaluation. In multivariate analysis, non-neuroradiologists were more likely to miss large-vessel occlusion compared with neuroradiologists (OR = 5.62; 95% CI, 1.06-29.85; P = .04), and occlusions of the M2 segment were more likely to be missed compared with occlusions of the distal internal carotid artery and/or M1 segment (OR = 5.69; 95% CI, 1.44-22.57; P = .01). There were no calcified emboli in initially correctly identified large-vessel occlusions. However, calcified emboli were present in 4 of 17 (24%) initially missed or misinterpreted large-vessel occlusions. Several factors may have an association with missing a large-vessel occlusion on CTA, including the CTA interpreter (non-neuroradiologists versus neuroradiologists), large-vessel occlusion location (M2 segment versus the distal internal carotid artery and/or M1 segment), and large-vessel occlusion caused by calcified emboli. Awareness of these factors may improve the accuracy in interpreting CTA and eventually improve stroke outcome.

Endovascular Thrombectomy of Calcified Emboli in Acute Ischemic Stroke: A Multicenter Study.

Large intracranial vessel occlusion due to calcified emboli is a rare cause of major stroke. We assessed the prevalence, imaging appearance, the effectiveness of mechanical thrombectomy, and clinical outcome of patients with large-vessel occlusion due to calcified emboli. We performed a retrospective analysis of clinical and procedural data of consecutive patients who underwent mechanical thrombectomy due to calcified emboli in 7 European stroke centers. We screened 2969 patients, and 40 patients matched the inclusion criteria, accounting for a prevalence of 1.3%. The mean maximal density of the thrombus was 327 HU (range, 150-1200 HU), and the mean thrombus length was 9.2 mm (range, 4-20 mm). Four patients had multiple calcified emboli, and 2 patients had an embolic event during an endovascular intervention. A modified TICI score of ≥2b was achieved in 57.5% (23/40), with minimal-to-no reperfusion (modified TICI 0-1) in 32.5% (13/40) and incomplete reperfusion (modified TICI 2a) in 10% (4/40). Excellent outcome (mRS 0-1) was achieved in only 20.6%, functional independence (mRS 0-2) in 26.5% and 90-day mortality was 55.9%. Acute ischemic stroke with large-vessel occlusion due to calcified emboli is a rare entity in patients undergoing thrombectomy, with considerably worse angiographic outcome and a higher mortality compared with patients with noncalcified thrombi. Good functional recovery at 3 months can still be achieved in about a quarter of patients.

Incidence and predictors of calcified cerebral emboli detected in patients who underwent endovascular procedures

ObjectivesThere are very few reports on calcified cerebral emboli associated with endovascular procedures. We aimed to evaluate the incidence rates and predictors of calcified cerebral emboli in patients who underwent carotid artery stenting (CAS)/percutaneous transluminal angioplasty (PTA). Patients and methodsPatient demographics, clinical characteristics, and operative records of patients who underwent CAS/PTA were retrospectively analyzed. A total of 211 consecutive patients with cervical internal carotid stenosis were included in this study. Patients were categorized according to the presence of calcified cerebral emboli in postoperative computed tomography (CT) into emboli and non-emboli groups. We defined calcified emboli as a CT value of 60–400 Hounsfield units. ResultsOn postoperative non-contrast CT, calcified emboli were detected in 5 of the 211 cases after CAS/PTA. The emboli were located in the middle cerebral artery (2/5), anterior cerebral artery (1/5), posterior cerebral artery (2/5). All of the cases of calcified cerebral emboli were clinically asymptomatic. The characteristics of patients showed no apparent difference in this study. Although the limited number may be attributed to a lack of statistical power, the average baseline activated clotting time (ACT) was lower in the emboli group than in the non-emboli group (117 vs 153, p < 0.05), and the operative time was longer in the emboli group than in the non-emboli group (147 vs 111, p < 0.05). ConclusionCalcified cerebral emboli may be more common than previously known. Lower average baseline ACT and longer operative time could be predictors of calcified cerebral emboli after endovascular procedures.

Urgent Middle Cerebral Artery Embolectomy of Calcified Embolus After Intravenous Thrombolysis: 2-Dimensional Operative Video.

This video shows an urgent microsurgical embolectomy of the inferior division of the left middle cerebral artery in a patient treated by intravenous thrombolysis (IVT). Patient was eligible for endovascular mechanical thrombectomy1; however, the interventional radiologist was not comfortable performing the procedure given prior unsuccessful attempts to remove a calcified cerebral embolus.2 A 75-yr-old female presented with an acute ischemic stroke with isolated aphasia (NIHSS 9). Using the drip-and-ship concept, IVT (0.9 mg/kg rt-PA) was administered in a regional hospital. Fifty-five minutes after a complete recovery following IVT, multiple transient ischemic attacks of aphasia were observed. While the patient was a candidate for mechanical thrombectomy based on CT perfusion imaging, given the unsuccessful reports in the literature and the interventional radiologist's experience, the decision was made to offer microsurgical embolectomy of the calcified cerebral embolus.3 Informed consent for the procedure was obtained directly from the patient. Calcified, crumbly embolus was removed from a 5 mm longitudinal arteriotomy. The arteriotomy was sutured with interrupted 10-0 suture. Initial flow after the embolectomy was 6.5 mL/min. Upon inspection, a distal kink was found in the M2 and after repositioning, flow improved to 35 mL/min.Postoperative CT angiography documented complete recanalization. The clinical findings completely resolved (NIHSS 0) within 12 hr and remained unchanged at 3 mo and 1 yr.Informed consent was obtained from the patient for use of media for educational and publication purposes.

Commentary: Urgent Middle Cerebral Artery Embolectomy of Calcified Embolus After Intravenous Thrombolysis: 2-Dimensional Operative Video.

Commentary: Urgent Middle Cerebral Artery Embolectomy of Calcified Embolus After Intravenous Thrombolysis: 2-Dimensional Operative Video.

Iatrogenic embolization following cardiac intervention: postmortem analysis of 110 cases.

Iatrogenic embolization following cardiac investigative procedures may result from hydrophilic polymer emboli (HPE) from catheter valve and vessel wall calcifications, and air embolism from open heart surgery. This retrospective clinical pathologic analysis was undertaken to ascertain the frequency and extent of these potentially fatal complications. This retrospective clinical pathologic autopsy analysis with premortem diagnostic imaging correlation identified 110 individuals who had undergone endovascular procedures between 2010 and 2016 within 90 days of death and followed by hospital autopsy. Clinical outcomes, radiologic studies, and autopsy materials were reviewed. Iatrogenic emboli were assessed as causing death in 9/110 autopsy cases (8.2%) and 9/34 (26.5%) cases with proven iatrogenic emboli. Iatrogenic emboli caused strokes in 10/110 (9.1%) autopsy cases including calcified emboli (CE, n=6), HPE (n=2), cardiac valvular tissue (n=1), and air embolism (n=1). Seven cases of calcified emboli complicating endovascular procedures were identified: four of the CE were thought to be the cause of death due to fatal strokes (n=2) and fatal myocardial (n=1) and colonic infarction (n=1). The CE likely originated from calcified aortic valves and atherosclerotic aortic plaques. Histologic evidence of HPE was found in 23% (25/110) of cases; 54% (26/48) showed evidence of infarction in postprocedural imaging, with radiologic evidence of infarction in 32% (8/25) of cases with HPE histology. Endovascular aortic repair was associated with the greatest density/distribution of HPE. HPE material showed degradation with time and was often associated with an inflammatory response. HPE directly contributed to death in three cases. One fatal air embolism followed open heart surgery, and one cardiac tissue embolus resulted in a major stroke. We advocate for greater awareness of these underrecognized and occasionally fatal complications of endovascular procedures. Targeted postprocedural imaging has a role in the identification of iatrogenic embolic infarcts.

Calcified cerebral emboli: Incidence and implications.

Calcified cerebral emboli are an increasingly recognized cause of ischaemic stroke, although recognition amongst general radiologists and clinicians can be limited. Recent literature suggests that calcified cerebral emboli are likely more common than originally thought. This study aims to define the prevalence of calcified cerebral emboli as the most likely aetiology within a cohort of confirmed cases of acute stroke, as well as compare and contrast these cases with cases of 'incidental' intracranial calcification. Cases of confirmed stroke between May 2014 and May 2017 were reviewed by two readers to assess for the most likely aetiology. Cases of presumed calcified cerebral embolus were categorized in to 'possible' or 'definite'. The morphology, distribution and density were analysed by two independent readers, then subsequently discussed to reach a consensus. Cases were further studied in terms of likely proximal embolic source, therapeutic interventions and clinical outcomes. A further random selection of 220 non-contrast CT head examinations were reviewed over the same time period to assess for the presence of calcification which was favoured to be 'intravascular' using the same criteria. A total of 220 cases of confirmed stroke were reviewed. Thirteen of these cases were thought to be most likely secondary to calcified cerebral emboli (5.9%). Of the 13 cases, eight were considered 'definite' as previous premorbid imaging without calcification was available. Twelve patients had emboli within the anterior circulation and only one patient had an embolus in the posterior circulation. Moderate calcified atherosclerotic disease was noted within the aorta and carotid arteries of all patients. Of the 220 patients within the control group, three cases were thought to have intracranial calcification most likely to be intravascular without clinical sequelae or other supportive imaging findings of infarct. Previously thought to be a rare complication of intra-arterial instrumentation, calcified cerebral emboli have been shown to more commonly be associated with spontaneous cerebral infarction. Whilst literature in this area remains scant, recognition and differentiation of this entity has important clinical applications regarding immediate diagnosis of stroke on non-contrast imaging, modified treatment in the acute setting as well as in regards to recurrent event prognosis and secondary prevention.

Thrombectomy of calcified emboli in stroke. Does histology of thrombi influence the effectiveness of thrombectomy?

Background and purposeThrombus composition has been postulated to affect the success of endovascular therapy. Calcified clots are composed of large amounts of calcium phosphate which influences their mechanical properties and...

Manual Aspiration Thrombectomy in Patients with Acute Stroke-Related Calcified Cerebral Emboli

The aim of this study was to evaluate the effectiveness of mechanical aspiration thrombectomy (MAT) in patients with acute ischemic stroke from calcified cerebral emboli. Procedural results were reviewed for acute stroke patients with clinically neurological deficits who underwent recanalization from October 2012 through September 2015. Initial imaging studies and cerebral angiography were analyzed. Of the total number of patients with acute stroke, 5 patients were confirmed to have acute ischemic stroke by calcified cerebral emboli. On initial brain computed tomographic imaging, all patients showed small, dense single calcifications in the middle cerebral artery with no definitive ischemic low-density lesions (M1: 3, M2: 2, mean size: 4.8 mm). All patients had angiographic findings of filling defects from calcified emboli. Four patients had good collateral flow and two had continuous distal flow. All patients underwent MAT using a Penumbra catheter (Penumbra Inc., Alameda, CA). MAT did not remove calcified emboli in all patients. Two patients with good collateral flow had favorable functional outcomes (modified Rankin Scale score ≤2). Four patients had diffuse calcification in the aortic arch, carotid artery, and aortic valve. Cerebral angiography supports a diagnosis of stroke when calcified cerebral emboli have contrast-filling defects and a degree of vascular occlusion. However, in this study, MAT was not an effective treatment for patients with calcified cerebral emboli because of hardness of the calcified plaque and packing into the arterial lumen.

The Characteristics of Retinal Emboli and its Association With Vascular Reperfusion in Retinal Artery Occlusion.

To analyze the characteristics of retinal emboli and their association with vascular reperfusion in retinal artery occlusion (RAO). In this retrospective comparative case series, we analyzed emboli in patients with acute central retinal artery occlusion (CRAO) or branch retinal artery occlusion (BRAO) and visible emboli, and analyzed vascular reperfusion in patients with visible emboli causing blockage of perfusion. The patients were divided into emboli "movement" and "no movement" groups and their vascular reperfusion states were compared. There were 52/248 (21%) eyes with RAO and visible retinal emboli (31/187 [17%] eyes with CRAO and 21/61 [34%] eyes with BRAO) showing various embolic features. Platelet-fibrin emboli were observed most commonly, and showed the earliest and highest rate of movement. In the movement group, which comprised platelet-fibrin (60%) and cholesterol (40%) emboli, early complete reperfusion was observed in 80% of eyes; however, 67% of eyes in the no movement group, comprising cholesterol (67%) and calcific (33%) emboli, showed late incomplete reperfusion. There were no cases of permanent vascular blockage. The mechanisms of vascular reperfusion could be summarized as complete degradation, peripheral migration, partial dislodgement, angiophagy, and collateral circulation. Retinal emboli in RAO patients have various characteristics that affect their movement. Movement of emboli may affect vascular reperfusion. Various mechanisms are associated with vascular reperfusion, including in cases without movement of emboli. These mechanisms may apply to cerebrovascular occlusion and stroke in general.

Histological Evidence of Artery to Artery Embolism from Calcified Atherosclerotic Plaque of Carotid Artery

Artery to artery embolism is one of the main causes of cerebral infarction, and it can originate from many locations. Here we report a case of cerebral infarction in which calcified cerebral emboli were detected in brain computed tomography (CT). The calcified emboli were thought to originate from a carotid plaque that showed calcification and ulceration. We present histologic and micro-CT findings of a carotid plaque as a source of artery to artery embolism. Key Words: Artery to artery embolism, Calcified emboli, Carotid plaque

Maroc : la kinésithérapie esthétique entre dérive et progrès

Computed tomographic angiography (CTA) is a quick and accurate method in triage to determine recanalization therapies for acute ischemic stroke. To minimize delay in the start of recanalization therapies, performance of CTA immediately after unenhanced brain computed tomography (CT) is recommended as the minimum standard. However, there are some pitfalls related to image interpretation of CTA in acute stroke, such as false patency sign. We describe the case of a 66-year-old man who presented with acute middle cerebral artery (MCA) occlusion by a calcified embolus with false patency sign on CTA after coronary angiography. We misinterpreted the CTA image as a patent MCA, and unnecessary brain magnetic resonance imaging caused delay in the start of endovascular thrombectomy. Our findings suggest that calcified cerebral emboli can present with false patency sign on CTA. To avoid misinterpretation of the CTA image and start recanalization therapy as soon as possible, physicians should be aware of false patency sign, especially when unenhanced CT shows hyperdense emboli and CTA findings do not correspond with patients' symptoms in acute ischemic stroke.

Calcific emboli originating from the brachiocephalic trunk causing acute cerebral infarction and worm-like calcification in the right middle cerebral artery

We report, to our knowledge, the first patient with brachiocephalic trunk calcified plaque causing the ‘salted pretzel sign’ and worm-like calcification. Arterial stenosis or occlusion caused by atherosclerosis and thrombosis are responsible for the majority of cases of cerebral infarction. However, there are a number of other causes. Interestingly, these findings were not observed on a CT scan 10days before the stroke. Acute cerebral infarction with calcifications on unenhanced head CT scans should raise suspicion for disease in the carotid system. Identification of subtle findings of acute ischemic stroke on CT scans is important for early diagnosis and treatment.

Calcified Cerebral Emboli, A "Do Not Miss" Imaging Diagnosis: 22 New Cases and Review of the Literature

Calcified cerebral emboli are a rarely reported but devastating cause of stroke and may be the first manifestation of vascular or cardiac disease. Our aim was to evaluate the diagnosis, prevalence, imaging appearance, presumed embolic source, treatment, and outcome of patients with calcified cerebral emboli. Our radiology information system was searched for all CT scans by using keywords "calcified," "emboli," and their permutations. The radiology information system was also searched to identify all "stroke" CT reports to calculate the prevalence of calcified cerebral emboli. We also performed a MEDLINE search to identify all published case reports. Twenty-two cases were identified from our database, and 48 were cases reported from the literature. The middle cerebral artery was the site of 83% of calcified emboli. Presumed sources were calcific aortic stenosis (36%), carotid atherosclerotic plaque (30%), and mitral annular calcification (11%). Spontaneous embolism occurred in 86%. Surgical treatment was performed in 34% of patients. Sixty-four percent of the patients with calcified aortic stenosis underwent aortic valve replacement. Among those with identifiable arterial disease, 53% underwent endarterectomy. Forty-one percent of patients experienced at least 1 recurrent stroke. The prevalence of calcified cerebral emboli identified on stroke CT scans at our institution was 2.7%. Seventy-three percent of cases were correctly identified. Twenty-seven percent were misdiagnosed on initial interpretation, while 9% were overlooked on preliminary interpretation. Calcified cerebral emboli are more common than previously assumed, are frequently overlooked or misinterpreted, affect clinical course when diagnosed, and carry substantial risk for recurrent stroke.