Theodoros Karapanayiotides

Catastrophic reaction in acute stroke: A reflex behavior in aphasic patients

Twelve patients with a catastrophic reaction (CR) (an outburst of frustration, depression, and anger when confronted with a task) were identified in a prospective cohort population (n = 326) with first-ever stroke admitted within 48 hours from onset. The authors’ findings suggest that CR is a rare though not exceptional phenomenon in acute stroke and is associated with nonfluent aphasias and left opercular lesions. CR, poststroke depression, and emotionalism are distinct but related disorders.

Controlled Contrast Transcranial Doppler and Arterial Blood Gas Analysis to Quantify Shunt Through Patent Foramen Ovale

Background and Purpose— A right-to-left shunt can be identified by contrast transcranial Doppler ultrasonography (c-TCD) at rest and/or after a Valsalva maneuver (VM) or by arterial blood gas (ABG) measurement. We assessed the influence of controlled strain pressures and durations during VM on the right-to-left passage of microbubbles, on which depends the shunt classification by c-TCD, and correlated it with the right-to-left shunt evaluation by ABG measurements in stroke patients with patent foramen ovale (PFO). Methods— We evaluated 40 stroke patients with transesophageal echocardiography–documented PFO. The microbubbles were recorded with TCD at rest and after 4 different VM conditions with controlled duration and target strain pressures (duration in seconds and pressure in cm H2O, respectively): V5-20, V10-20, V5-40, and V10-40. The ABG analysis was performed after pure oxygen breathing in 34 patients, and the shunt was calculated as percentage of cardiac output. Results— Among all VM conditions, V5-40 and V10-40 yielded the greatest median number of microbubbles (84 and 95, respectively; P <0.01). A significantly larger number of microbubbles were detected in V5-40 than in V5-20 (P <0.001) and in V10-40 than in V10-20 (P <0.01). ABG was not sensitive enough to detect a shunt in 31 patients. Conclusions— The increase of VM expiratory pressure magnifies the number of microbubbles irrespective of the strain duration. Because the right-to-left shunt classification in PFO is based on the number of microbubbles, a controlled VM pressure is advised for a reproducible shunt assessment. The ABG measurement is not sensitive enough for shunt assessment in stroke patients with PFO.

Ultrasound Measurement of the Fibrous Cap in Symptomatic and Asymptomatic Atheromatous Carotid Plaques

Background—Fibrous cap thickness (FCT) is an important determinant of atheroma stability. We evaluated the feasibility and potential clinical implications of measuring the FCT of internal carotid artery plaques with a new ultrasound system based on boundary detection by dynamic programming. Methods and Results—We assessed agreement between ultrasound-obtained FCT values and those measured histologically in 20 patients (symptomatic [S]=9, asymptomatic [AS]=11) who underwent carotid endarterectomy for stenosing (>70%) carotid atheromas. We subsequently measured in vivo the FCT of 58 stenosing internal carotid artery plaques (S=22, AS=36) in 54 patients. The accuracy in discriminating symptomatic from asymptomatic plaques was assessed by receiver operating characteristic curves for the minimal, mean, and maximal FCT. Decision FCT thresholds that provided the best correct classification rates were identified. Agreement between ultrasound and histology was excellent, and interobserver variability was small. Ultrasound showed that symptomatic atheromas had thinner fibrous caps (S versus AS, median [95% CI]: minimal FCT=0.42 [0.34 to 0.48] versus 0.50 [0.44 to 0.53] mm, P=0.024; mean FCT=0.58 [0.52 to 0.63] versus 0.79 [0.69 to 0.85] mm, P<0.0001; maximal FCT=0.73 [0.66 to 0.92] versus 1.04 [0.94 to 1.20] mm, P<0.0001). Mean FCT measurement demonstrated the best discriminatory accuracy (area under the curve [95% CI]: minimal 0.74 [0.61 to 0.87]; mean 0.88 [0.79 to 0.97]; maximal 0.82 [0.71 to 0.93]). The decision threshold of 0.65 mm (mean FTC) demonstrated the best correct classification rate (82.8%; positive predictive value 75%, negative predictive value 88.2%). Conclusions—FCT measurement of carotid atheroma with ultrasound is feasible. Discrimination of symptomatic from asymptomatic plaques with mean FCT values is good. Prospective studies should determine whether this ultrasound marker is reliable.

Prodromal and early epileptic seizures in acute stroke Does higher serum cholesterol protect

In a case-control study, patients (n = 43/3,628) presenting seizures <1 week before (n = 6), ≤3 hours after (n = 26), and 3 to 24 hours after (n = 11) a first-ever stroke were studied. On multivariate analysis, they were characterized by lower levels of serum cholesterol (5.86 ± 0.51 vs 6.34 ± 0.58; p < 0.0001). Mortality and functional outcome at discharge were not influenced. Early poststroke seizures occur mainly during the critical 3-hour window for thrombolysis. Hypercholesterolemia appears to protect against seizures and cerebral ischemia.

Solid or Gaseous Circulating Brain Emboli: Are They Separable by Transcranial Ultrasound?:

High-intensity transient signals (HITS) detected by transcranial Doppler (TCD) ultrasound may correspond to artifacts or to microembolic signals, the latter being either solid or gaseous emboli. The goal of this study was to assess what can be achieved with an automatic signal processing system for artifact/microembolic signals and solid/gas differentiation in different clinical situations. The authors studied 3,428 HITS in vivo in a multicenter study, i.e., 1,608 artifacts in healthy subjects, 649 solid emboli in stroke patients with a carotid stenosis, and 1,171 gaseous emboli in stroke patients with patent foramen ovale. They worked with the dual-gate TCD combined to three types of statistical classifiers: binary decision trees (BDT), artificial neural networks (ANN), and support vector machines (SVM). The sensitivity and specificity to separate artifacts from microembolic signals by BDT reached was 94% and 97%, respectively. For the discrimination between solid and gaseous emboli, the classifier achieved a sensitivity and specificity of 81% and 81% for BDT, 84% and 84% for ANN, and 86% and 86% for SVM, respectively. The current results for artifact elimination and solid/gas differentiation are already useful to extract data for future prospective clinical studies.

Carotid Stenosis: Looking Beyond the Lumen With Ultrasound

To the Editor: We read with great interest the article by Wasserman et al.1 It represents an excellent review on the importance of carotid wall–imaging in decision-making in contemporary vascular neurology. The authors are to be congratulated for the excellent presentation of their case and for their keen comments. Unfortunately, MRI of carotid atheromata has a number of important limitations, as stated by the authors, and it seems little …

Fibrous Cap Thickness and Stability of Carotid Atheromata

To the Editor: We read with great interest the article by Li et al.1 The authors are to be congratulated for their excellent study. We totally agree that clinical decision-making in patients with carotid disease should take into consideration plaque morphology (eg, fibrous cap thickness) as well as the degree of lumen stenosis. However, we would like to express some concerns on the potential clinical implications of the study. In our view, the title of the article is somewhat misleading: although the authors intended to construct a flow-(internal carotid) plaque interaction model, they essentially created a model that, despite differences in vessel diameter, would better represent atheromatous disease in the common carotid artery, the distal internal carotid artery, the coronaries or the lower …

Letter by Karapanayiotides regarding article, "Histological assessment of 526 symptomatic carotid plaques in relation to the nature and timing of ischemic symptoms: the Oxford plaque study".

To the Editor: I read with great interest the article by Redgrave et al.1 The authors are to be congratulated for the completion of a burdensome work and the excellent presentation of their results. Their contribution to our understanding of carotid atheromatic disease is paramount. However, I would like to ask the authors the following questions. First, in view of the high frequency of cap rupture in unstable plaques, was there …

Fibrous Cap Thickness and Rupture in Carotid Atheromata: Still Hunting in the Dark?

To the Editor: Redgrave et al1 are to be congratulated for their superb and cumbersome work. We had been waiting for a large well-designed histopathologic study focusing exclusively on the critical cap thickness of carotid atheromata, and we are grateful for this important contribution. Hitherto, data extrapolation from coronary pathology to the carotids had left to vascular neurologists the bitter taste of hunting in the dark. We had published 3 years ago the first in vivo study of cap thickness measurement in carotid atheromata2 and had proposed a threshold of 650 μm for the mean cap thickness for the differentiation between symptomatic and asymptomatic plaques. The currently proposed threshold of 500 μm1 for representative cap thickness, in my view, lies in full accordance with our results, if one considers the fundamental methodological differences between …