Is Histologic Thrombus Composition in Acute Stroke Linked to Stroke Etiology or to Interventional Parameters?

BACKGROUND AND PURPOSE: Detailed insight into the composition of thrombi retrieved from patients with ischemic stroke by mechanical thrombectomy might improve pathophysiologic understanding and therapy. Thus, this study searched for links between histologic thrombus composition and stroke subtypes and mechanical thrombectomy results. MATERIALS AND METHODS: Thrombi from 85 patients who had undergone mechanical thrombectomy for acute ischemic stroke between December 2016 and March 2018 were studied retrospectively. Thrombi were examined histologically. Preinterventional imaging features, stroke subtypes, and interventional parameters were re-analyzed. Statistical analysis was performed with the Kruskal-Wallis test, Mann-Whitney U test, or Spearman correlation as appropriate. RESULTS: Cardioembolic thrombi had a higher percentage of macrophages and a tendency toward more platelets than thrombi of large-artery atherosclerotic stenosis (P = .021 and .003) or the embolic stroke of undetermined source (P = .037 and .099) subtype. Thrombi prone to fragmentation required the combined use of contact aspiration and stent retrieval (P = .021) and were associated with an increased number of retrieving maneuvers (P = .001), longer procedural times (P = .001), and a higher lymphocyte content (P = .035). CONCLUSIONS: We interpreted the higher macrophage and platelet content in cardioembolic thrombi compared with large-artery atherosclerotic stenosis or embolic stroke of undetermined source thrombi as an indication that the latter type might be derived from an atherosclerotic plaque rather than from an undetermined cardiac source. The extent of thrombus fragmentation was associated with a more challenging mechanical thrombectomy and a higher lymphocyte content of the thrombi. Thus, thrombus fragmentation not only might be caused by the recanalization procedure but also might be a feature of a lymphocyte-rich, difficult-to-retrieve subgroup of thrombi.

[The effect of muscle relaxants on masseter tone. An experimental study in an MH-susceptible swine model]. / Zur Wirkung von Muskelrelaxanzien auf den Massetertonus. Eine experimentelle Studie am MH-disponierten Schweinemodell.

Malignant hyperthermia (MH) may occur, when a genetically predisposed individual or pig (MHS) is exposed to triggering agents. The increase in free, ionized sarcoplasmic calcium inducing the vicious circle of MH is believed to result from calcium-induced release with volatile anaesthetics, and from depolarization-induced calcium release with succinylcholine (SCH). The administration of SCH to susceptible humans or pigs frequently produces an increase in masticatory muscle tone. This hitherto ill-defined phenomenon is referred to as "masseter spasm" (MS). We have attempted to elucidate the pathophysiology of MS in a porcine model. METHODS. After the protocol had been approved by the state authorities, 6 MHS pigs were investigated. The pigs were mixed breeds (German Landrace and Dutch Pietrain) and were 9 +/- 1 weeks old with an average body weight of 25.5 kg. Premedication consisted of intramuscular injection of azaperone, 7.5 mg.kg-1. Anaesthesia was induced with piritramide, 1.2 mg.kg-1, administered via a cannulated ear vein. Subsequent to laryngoscopic endotracheal intubation, neuromuscular blockade was achieved with 4 mg pancuronium. Ventilation was set at 12 breaths per minute and adjusted to maintain an end-tidal CO2 concentration of 4.7% by adapting the tidal volume (PhysioFlex). Anaesthesia was maintained with piritramide, 2.25 mg.kg-1.h-1, pancuronium, 0.4 mg.kg-1.h-1, and N2O (60% in O2). Instrumentation included an arterial line, a central venous line, and a fiberoptic pulmonary artery catheter (Oximetrix). Masticatory muscle tone (MMT) was assessed with an intermolar balloon, connected to a pressure transducer and calibrated to zero prior to SCH administration. As a reference variable for effects produced by SCH, intraocular pressure (IOP) was measured manometrically in the anterior chamber. After stabilization of haemodynamic variables, the neuromuscular blockade was allowed to wear off. After recovery of the evoked masseter electromyogram, a paralyzing dose of pancuronium was administered (0.5 mg.kg-1). When paralysis was complete, SCH was administered (1.5 mg.kg-1), followed a few minutes later by dantrolene infusion (5 mg.kg-1 over 10 min). RESULTS. The administration of SCH was followed by clinically unequivocal MH episodes in all pigs, indicated by an increase in oxygen uptake (VO2; PhysioFlex; Fig. 1) and end-tidal CO2 concentration and a decrease in oxygen saturation of mixed venous blood (svO2; Fig. 2). Despite complete neuromuscular blockade (monitored with EMG), SCH produced an increase in MMT in all pigs which was reversed by dantrolene (Fig. 3). The time course of MMT paralleled that of IOP, suggesting a similar underlying mechanism. DISCUSSION. Succinylcholine is a trigger of MH in susceptible individuals; onset of the syndrome may be associated with "masseter spasm". SCH increases extraocular muscle tone, probably by means of stimulating multiply innervated fibers; the resulting IOP increase is not prevented by competitive neuromuscular blockade. The existence of multiple innervated fibers has also been shown in muscle spindles in the deep layers of the masseter, with their stimulation resulting in elevation of the jaw. We speculate that the increases in MMT and IOP observed in this study reflect the same process, i.e. a motor response, initiated by SCH-induced stimulation of the intramyocellular contractile system of multiply innervated muscle fibers, that is independent of neuromuscular transmission. Triggering of MH with SCH despite complete neuromuscular blockage suggests a mechanism other than depolarization-induced calcium increase. And, for the semantics, according to neurological terminology MS should be referred to as contracture not as spasm.

[Infectious endocarditis from the morphologic viewpoint: on the pathology and clinical aspects of 97 autopsy cases]. / Infektiöse Endokarditis aus morphologischer Sicht: Zur Pathologie und Klinik von 97 obduzierten Fällen.

In continuous autopsy material between 1978 and 1987 an infectious endocarditis was present in 97 cases of 8745 postmortem examinations. Hospital acquired or iatrogenic infections were at the top of the list with 60% contribution and intravasal devices, cardiovascular or abdominal surgery acting as predominant entrance spots of the infection. In community acquired disease the portal of entry could not be ascertained in most of the cases. The spectrum of causative organisms showed staphylococcus aureus in first position (37%), followed by enterococci (20%), candida (12%) and gram-negative rods (10%). Streptococcus viridans could be isolated in only one case. The majority of patients already had cardiac valve lesions before the onset of infection (48%), immune-defence tangent illnesses (47%) and/or were treated immunosuppressively (14%). In many of the patients, however, no predisposing factors could be established. Factors determining the clinical outcome were - independent of the localization - the local destruction (47%), purulent and non-purulent myocarditis (58%), fresh myocardial infarction (17%) and embolization to various organs (76%), whereby the central nervous system was affected to a high degree (43%). Only 39% of the analyzed cases were discovered at lifetime; especially mural (n = 10) and tricuspidal (n = 9) infections were overlooked. In spite of highly suspicious infection parameters, blood-cultures were drawn from only 59% of the patients; however, an antibiotic therapy had been given to 85%. Only through an early diagnosis before serious complications set in, the poor prognosis of infectious endocarditis can be improved by specific chemotherapy and well-timed surgical measures.

[Anesthesiology problems in Takayasu's syndrome]. / Anaesthesiologische Probleme beim Takayasu-Syndrom.

Takayasu's disease is a rare form of nonspecific obliterative panarteritis of unknown origin, mainly located at supraaortic, renal, and pulmonary arteries and resulting in multiple stenoses and occlusion of major arteries. Predominantly young women in the first three decades of life are affected. Absence of arm pulses, vascular bruits, and retinopathy are classic symptoms. Another symptom is hypertension of the lower extremities and hypotension of the upper extremities, thus potentially impairing cerebral perfusion. A 25-year-old female patient with a 2-year history of Takayasu's disease presented for therapeutic abortion on the grounds of her medical condition. There were significant stenoses of the left common carotid artery and the internal carotid artery. The left subclavian artery was totally obliterated. The arterial blood supply to the left arm was accomplished by the left vertebral artery via a subclavian steal syndrome. Brachial and radial pulses were absent in both arms. General, spinal or epidural anesthesia can produce arterial hypotension. Blood pressure assessment at the lower extremities does not allow conclusions about perfusion of supraaortic arteries and cerebral perfusion pressure. Thus, a paracervical block was performed; sedation and analgesia were achieved with small doses of midazolam and alfentanil. We planned that if general anesthesia became necessary we would induce anesthesia with etomidate and alfentanil and maintain anesthesia by mask ventilation with nitrous oxide in oxygen and supplementary doses of alfentanil. Invasive monitoring such as arterial or Swan Ganz catheterization, was contraindicated because of the possibility that inflamed vessels would become irritated. Therefore, we only monitored ECG, blood pressure at the leg, ventilation parameters, and oxygen saturation at the ear lobe by pulse oximetry.(ABSTRACT TRUNCATED AT 250 WORDS)

[Characteristics of cardiopulmonary resuscitation in pregnant women]. / Besonderheiten der kardiopulmonalen Reanimation (CPR) bei Schwangeren.

Cardiopulmonary resuscitation (CPR) during pregnancy is a rare event, but due to the increasing number of pregnant women with significant medical disorders it will gain more importance in the near future. Effective CPR with respect to survival of mother and infant can only be accomplished under optimal conditions. We discuss important pathophysiological alterations during pregnancy and, including recommendations in the available literature, we present a standardized protocol for life support for mother and infant. The protocol depends on the progress of the pregnancy. Compared to non-pregnant patients, pregnant women must be placed in a left lateral position immediately. If possible, the decision to perform open-chest CPR has to be made within 15 min of unsuccessful closed-chest CPR. In addition, during late pregnancy there should be no delay in performing an emergency cesarean section, even during CPR.