Dynamic Evolution of Diffusion-Weighted Imaging Lesions in Patients With Minor Ischemic Stroke

BACKGROUND AND PURPOSE

Diffusion-weighted imaging (DWI) lesion volume on magnetic resonance imaging is increasingly being used as a surrogate outcome measure in clinical trials. We aimed to characterize the evolution of DWI lesion volumes within 30 days of symptom onset after minor stroke.

METHODS

Minor stroke patients with DWI lesions on magnetic resonance imaging within 48 hours of symptom onset were prospectively followed with magnetic resonance imaging brain scan at 7 and 30 days. Change in the lesion volume was defined as the difference between day 30 Fluid-Attenuated Inversion Recovery and baseline DWI lesion volumes.

RESULTS

Three patterns of infarct evolution were observed: reduction (72 [63%]), no change (26 [23%]), and growth (16 [14%]). Patients with infarct reduction at 30 days had larger baseline DWI lesion volumes (2.5 [0.9-8.5] mL) than those with stable infarcts (0.5 [0.3-0.9] mL; P=0.01). Complete DWI reversal at day 30, was seen in only 6 (5.3%) patients.

CONCLUSIONS

The most common pattern of infarct evolution in patients with minor stroke is a reduction in volume, but complete resolution is uncommon.

Abstract W P60: Blood Pressure Reduction In Acute Ischemic Stroke Does Not Affect Ischemic Core Tissue Perfusion

Introduction: Blood pressure (BP) reduction in acute ischemic stroke patients can potentially decrease cerebral blood flow (CBF) in ischemic tissue due to disrupted autoregulation, particularly in the ischemic core. We tested this hypothesis using a 3 group non-randomized controlled study of serial CBF measurements in ischemic stroke patients.

Methods: Patients with acute ischemic stroke ≤72h of symptom onset were recruited. Groups were assigned according to baseline mean arterial blood pressure (MAP): patients with MAP >120mmHg were treated with intravenous labetalol and sublingual (SL) nitroglycerin and those with MAP 100-120 mmHg were treated with SL nitroglycerin. The BP reduction target was 10% of the baseline MAP. Patients with MAP<100 mmHg formed the control group. Patients underwent MR perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) before and after BP reduction. Blinded planimetric assessment was done to determine PWI deficits and DWI lesion volumes in the ischemic core region.

Results: A total of 48 patients with mean±SD age of 65.4±13.2 years were enrolled at 23.4±15.3h after symptom onset. The mean time difference between perfusion scans was 25.6±9.5 min.Median(IQR) DWI volume was 11.1 (96.8) ml. Mean MAP was 126±7.5 mmHg in the MAP>120 group(n=13), 109.9±4.9 mmHg in the MAP 100-120 group (n=16), and 89.9±6.2 mmHg in the controls (n=19). Mean BP reduction in the treated patients was 11.9±6.7 mmHg (95% CI 15.6-3; p=0.04). Baseline mean relative CBF (rCBF) in ischemic core tissue was 1.1±0.47 in the MAP >120 group, 0.87±0.35 in the MAP 100-120 group and 0.78±0.32 in controls. The mean change in rCBF following BP reduction did not differ between the MAP >120 group (0.03±0.17), MAP 100-120 group (0.06±0.17) and controls (0.08±0.25) (p=0.28). Similarly, there was no difference in the mean relative cerebral blood volume (p=0.3) and relative mean transit time (p=0.58) before and after BP reduction. In patients treated with SL nitroglycerin (n=17), there was no improvement in mean lesional rCBF (0.04±0.17 vs.-0.02±0.18, p=0.25).

Conclusion: Modest BP reduction does not lead to an immediate decrease in CBF, within the ischemic core. Acute antihypertensive therapy may be less directly harmful than has been postulated.

Abstract W P306: Novel Oral Anticoagulant Initiation Within 14 days of Stroke Is Not Associated with Excess Hemorrhagic Transformation Rates

Introduction: The risk of early recurrent stroke after a cerebrovascular event is elevated. Despite a lack of safety data related to oral anticoagulation (OAC) after TIA/stroke in patients with atrial fibrillation (AF), particularly with respect to novel OACs (NOACs), many physicians do initiate therapy within 14 days of symptom onset. We aimed to assess current practice patterns and hemorrhagic transformation rates associated with early OAC use in AF patients. Methods: We conducted a retrospective chart review of AF patients admitted to a single stroke unit over a 24-month period. OAC agents and time from onset to initiation were recorded. Hemorrhagic transformation (HT) was assessed on CT scans and graded using the ECASS classification system (Hemorrhagic Infarction; HI and Parenchymal Hemorrhage; PH). Results: A total of 402 AF patients, with a mean age of 78.0±11.4 years (196 female), were included. OACs were initiated in 233 (58.0%) patients within 14 days of symptom onset. Of these 233 patients, warfarin was started in 136 (58.4%), dabigatran in 52 (22.3%), rivaroxaban in 40 (17.2%), and apixaban in 5 (2.1%). The median(IQR) number of days from onset to OAC initiation was similar between patients treated with warfarin (2.0(6.0)), dabigatran (2.0(3.8)), rivaroxaban (3.0(6.8)), and apixaban (3.0(5.5), P=0.44). HT was found in 10 patients, 7 (5.1%) of whom were initiated on warfarin and 3 (5.8%) on dabigatran (λ2= 2.9, P=0.14). Of the 7 warfarin related HT cases, 6 were asymptomatic HI and 1 was a symptomatic PH. All 3 dabigatran related HT cases were asymptomatic HI. HT was detected at a median of 3(4) days following OAC initiation. Systemic bleeding was seen in 7 patients, all of whom were taking warfarin (4 gastrointestinal bleeds, 2 retroperitoneal, and 1 ureteral hematoma). Conclusion: Off-label use of NOACs in acute stroke is common. Although hemorrhagic transformation rates appear to be no higher than those associated with warfarin, early NOAC initiation after stroke should be studied in a prospective fashion.

Abstract W MP112: Hematoma Contraction In Primary Intracerebral Hemorrhage Is Associated With Short-term Functional Outcome

Introduction: Although blood clot retraction is a normal part of wound healing, this process has never been documented in intracerebral hemorrhage (ICH). Using a serial imaging approach, we aimed to assess the frequency of hematoma contraction in ICH patients. We also tested the hypothesis that hematoma contraction is associated with increased perihematoma edema volumes.

Methods: We conducted a retrospective imaging study in primary ICH patients with a non-contrast CT (NCCT) study within 24h of symptom onset. All patients had a follow-up NCCT within 48h of the baseline scan. Patients who underwent any surgical intervention were excluded. Two blinded assessors, planimetrically measured hematoma and perihematoma edema volumes. Hematoma contraction was defined a priori as ≥10% reduction in ICH volume from baseline.

Results: A total of 202 patients with a mean±SD age of 67.9±15.1 years were included. The mean baseline ICH volume was 22.5±23.8ml. The mean difference in ICH volume between the two raters was 0.2±0.8ml (Intraclass correlation coefficient-0.93; 95% Limits of Agreement=0.82-0.95). Hematoma contraction of at least 10% from baseline was seen in 22 (10.9%) patients. The mean absolute change in volume in these patients was -3.9±4.2ml. Hematoma expansion occurred in 51 (25.2%) patients. There is no difference in mean interscan interval between patients with ICH contraction (26.1±11.7h), expansion (20.7±11.8h) or stability (24.2±10.6h, p=0.96). Baseline perihematoma edema volumes were larger in patients with subsequent hematoma contraction (8.9±9.7ml) than those with stable (2.6±2.8 ml) or expanding ICH (3.5±4.4 ml, p<0.0001). Perihematoma edema volume growth was greater in patients with hematoma expansion (7.8±12.11ml) than those with contracting (3.4±4.7ml), or stable ICH (1.6±3.2ml, p=0.004). Median (IQR) modified Rankin scale scores were lower in patients with hematoma contraction (3(2)) or stable hematomas (3(3)) than those with expansion (6(2), p<0.0001).

Conclusions: Hematoma contraction is evident in approximately 10% of ICH patients. Baseline perihematoma edema volume in patients with subsequent hematoma contraction is larger, which is consistent with the hypothesis that acute edema represents successful hemostasis.

Abstract 61: Safety and Feasibility of Acute Dabigatran Therapy in Minor Ischemic Stroke Patients Without Atrial Fibrillation

Introduction: Transient Ischemic Attack (TIA) and Minor ischemic stroke (MIS) patients are at high risk for recurrent events. Older anticoagulants are associated with a reduction in recurrent events, but also an increase in hemorrhagic transformation (HT). Dabigatran etexilate (DE), a novel oral anticoagulant that is associated with reduced risk of intracranial bleeding in atrial fibrillation (AF) patients, may be an effective therapy in this population. DE is not indicated within 14 days of ischemic stroke, due to an absence of data. We tested the feasibility and safety of initiating DE therapy within 24 h of TIA/MIS.

Methods: We designed a 50 patient single arm open label treatment trial. The primary endpoint was symptomatic HT within 30 days of enrolment. All patients underwent MRI prior to treatment. TIA/MIS patients (NIHSS score ≤3) with a DWI lesion were prospectively treated with DE 150 mg BID (110 mg BID in patients ≥ 80 or if CrCl <40 ml/min). Treatment began within 24 h of onset and continued for 30 days. Patients with known atrial fibrillation (AF) were excluded. Patients were re-imaged at day 7 and 30, with clinical assessment to 90 days.

Results: Forty-three of 50 patients have been enrolled to date (March 2012-August 2013). The mean age was 66±12 years and median (IQR) NIHSS was 1 (2). Median baseline DWI volume was 0.89(1.9) ml. The median time from onset to initial DE dose was 18.5 (12.2) h. Therapy was completed in 41 patients and discontinued in two (withdrawal of consent (1) and dysphagia (1)). Two patients died within the 90 day study period, both after completion of DE therapy. No patients experienced systemic bleeding or symptomatic intracranial hemorrhage. One patient had asymptomatic HT (ECASS grade, HI1) on day 7, which resolved by day 30 despite continuing DE. No patients experienced recurrent clinical stroke. New asymptomatic DWI lesions developed in 7 (16%) patients by day 30.

Conclusion: These preliminary data suggest DE may be used safely in acute TIA/MIS patients and larger randomized trials are warranted. The low HT rate may make DE an ideal antithrombotic for use immediately after TIA/ischemic stroke.

Abstract 33: Cerebral Blood Flow in Leukoaraiosis Regions is Unaffected by Acute Lowering of Blood Pressure in Intracerebral Hemorrhage Patients

Introduction: Leukoariosis(LA) is associated with poor prognosis in intracerebral hemorrhage (ICH) patients. Patients with chronic small vessel ischemic changes may be more vulnerable to decreases in cerebral perfusion, in both LA and perihematoma(PH) regions. We tested the hypotheses that acute blood pressure reduction (BP) in ICH patients is associated with decreased cerebral blood flow (CBF) in areas of LA and the PH region.

Methods: In the ICH Acutely Decreasing Arterial Pressure Trial (ICH ADAPT), patients with ICH <24 hours duration were randomized to two systolic BP (SBP) target groups (<150 mmHg vs. <180 mmHg). Computed tomography (CT) perfusion imaging was performed 2 h post-randomization. LA tissue volume was planimetrically measured on the acute non-contrast CT, using Hounsfield Unit thresholds of 15-25. CBF, cerebral blood volume (CBV), and Tmax were measured in the LA regions.

Results: Seventy-one patients were included with a mean age of 69.3±11.5 years and median (IQR) baseline NIHSS score of 10(11). LA was present in 74.6% (53/71) and the median volume was 8.5(20.6) ml. LA was associated with older age (70.9± 11.2 vs. 64.8 ±11.6, p=0.05) and larger ICH volumes (19.52(29.78) vs. 9.52(16.02) ml, p=0.007). Mean CBF in LA regions (32.5±13.5) was similar to that in normal appearing white matter (35.6±12.1, p=0.3). Despite a significant drop in SBP between aggressive (36.25(40) mmHg) and conservative (18.5(29) mmHg, p=0.01) treatment groups, relative CBF (rCBF) in LA regions was unaffected (0.88±0.1 vs. 0.89±0.09, p=0.6). Similarly, aggressive BP treatment did not affect relative CBV (0.83±0.16 vs. 0.82± 0.15, p=0.8) or Tmax (7.3±3.2 s vs. 6.5 ±2.4 s, p=0.3). The rCBF in the PH regions in patients’ with/without LA was similar (0.88±0.09 vs. 0.86±0.1, p=0.5). There was a trend to worse functional outcome at 90 days, measured with the modified Rankin Scale in patients with LA (4(4) vs. 2(1), p=0.06).

Conclusion: LA is associated with larger baseline ICH volumes, but no differences in perihematoma CBF or the response to BP reduction. CBF in LA tissue is also unaffected by BP reduction. These data do not support a less aggressive approach to BP reduction in elderly patients with imaging evidence of chronic small vessel ischemia.

Insular ischemic stroke: clinical presentation and outcome

Background

The insula is a small but complex structure located in the depth of the sylvian fissure, covered by the frontal, parietal and temporal operculum. Ischemic strokes limited to the insula are rare and have not been well studied. Our objective is to better define the clinical presentation and outcome of insular ischemic strokes (IIS).

Methods

We reviewed the institutional prospective, consecutive stroke database from two centers to identify patients with IIS seen between 2008 and 2010. We also searched the Medline database using the keywords insula(r), infarction and stroke to identify previously published IIS cases confirmed by MRI. Minimal extension to an adjacent operculum or subinsular area was accepted. Clinicoradiological correlation was performed by distinguishing IIS involving the anterior (AIC) or posterior insular cortex (PIC). We collected clinical, demographic and radiological data. The outcome was determined using the modified Rankin Scale (mRS).

Results

We identified 7 patients from our institutions and 16 previously published cases of IIS. Infarcts were limited to the AIC (n = 4) or the PIC (n = 12) or affected both (n = 7). The five most frequent symptoms were somatosensory deficits (n = 10), aphasia (n = 10), dysarthria (n = 10), a vestibular-like syndrome (n = 8) and motor deficits (n = 6). A significant correlation was found between involvement of the PIC and somatosensory manifestations (p = 0.04). No other statistically significant associations were found. IIS presentation resembled a partial anterior circulation infarct (n = 9), a lacunar infarct (n = 2) or a posterior circulation infarct (n = 2). However, most cases presented findings that did not fit with these classical patterns (n = 10). At the 6 month follow up, mRS was 0 in 8/23 (35%) patients, 1–2 in 7/23 (30%) and unknown in 8/23 (35%).

Conclusions

IIS presentation is variable. Due to the confluence of functions in a restricted region, it results in multimodal deficits. It should be suspected when vestibular-like or motor but especially somatosensory, speech or language disturbances are combined in the same patient. The outcome of IIS is often favorable. Larger prospective studies are needed to better define the clinical presentation and outcome of IIS.

Systemic adverse events during 2005 phacoemulsifications under monitored anesthesia care: a prospective evaluation

BACKGROUND

The aim of the study was to evaluate the systemic adverse events triggering on-call anesthesiologist's intervention during 2005 phacoemulsification under topical anesthesia on a day-surgery monitored anesthesia care regimen.

METHODS

Adverse events triggering an anesthesiologist call by the attending nurse were registered. Comorbidities (7 categories), age, gender, body mass index, ASA status, length of surgery, time of the day of surgery and operated eye (first/second) were analyzed as potentially predictive factors. Odds Ratios are expressed as OR (95% CI).

RESULTS

The anesthesiologist was called in 433 (21.6%) cases: age (5-yr-OR 0.95 [0.91-0.99]), ASA status 3-4 (OR 1.37 [1.02-1.85]), positive neurological history (OR 1.60 [1.06-2.40]), positive psychiatric history (OR 2.56 [1.34-4.93]) and length of surgery (OR 1.03 [1.01-1.06]) were predictive of the anesthesiologist call. Arterial hypertension (10.3%) and agitation (9.5%) were the most frequent adverse events. Age (5-yr-OR 1.27 [1.16-1.38]) and ASA status 3-4 (OR 1.83 [1.30-2.56]) were predictive of arterial hypertension. Age (5-yr-OR 0.80 [0.76-0.85]), positive neurological history (OR 1.86 [1.10-3.14]) and positive psychiatric history (OR 4.48 [2.26-8.88]) were predictive of agitation. Interruption of surgery was never required.

CONCLUSION

One-day cataract surgery performed under topical anesthesia with monitored anesthesia care required anesthesiologist intervention in 21.6% of cases, mainly because of agitation or hypertension. Agitation occurred more often in younger patients with neurological or psychiatric comorbidities. Hypertension occurred more often in older patients with higher ASA scores.

Primary Angiitis of the Central Nervous System - Clinical Approaches, Challenges and Controversies

Primary angiitis of the central nervous system (PACNS) is a rare and life-threatening form of vasculitis confined to the CNS. A timely diagnosis is a real challenge because clinical manifestations of PACNS are diverse and nonspecific. Headaches, cerebrospinal fluid inflammation and abnormal brain magnetic resonance imaging are prevalent. When PACNS is suspected, a thorough investigation is mandatory to rule out several potential simulators and confirm the diagnosis. Treatment of PACNS is also a challenge involving competing forces, which include the threat of serious adverse effects of potent immunosuppressive agents and the risk of neurological deteriorations due to insufficient immunosuppressant therapy. Efforts are ongoing to delineate subtypes requiring different therapeutic approaches and having distinct prognoses. Despite recent progress, PACNS is still fatal in as much as one-sixth of cases. Long-term follow-up is mandatory in patients with PACNS.

Fusion as the result of sperm–somatic cell interaction

The research has been designed to investigate whether acrosome-reacted spermatozoa can fuse with somatic cells and to check whether this event may involve the molecular machinery implicated in the sperm–egg fusion. Boar spermatozoa were capacitatedin vitroand then treated with A23187 to induce acrosome reaction and activate their fusogenic potential. Reacted spermatozoa, loaded with the membrane-permeant fluorescent dye calcein AM, were incubated with plated granulosa cells or cells derived from stable cell lines: CRFK, VERO, and ESK4. The fusion between spermatozoa and somatic cells was revealed by the diffusion of the fluorescent dye from the sperm to the cell as membrane fusion and cytoplasmic continuity between the two cells were established. The involvement of integrin α6 and tetraspanin CD9 in the process of fusion was assessed by carrying out the experiment in the presence of antibodies against these molecules. Moreover, the incidence of fusion displayed by the different cell types used was analyzed in relation to their content in the above molecules assessed by western blot and immunostaining. The role of CD9 was additionally investigated by using CD9-negative cells. The data presented demonstrate that boar spermatozoa can fuse with different somatic cell types derived from different species and the process requires the combined presence of both integrin and tetraspanin molecules on the cell plasma membrane.

Spatio-temporal analysis of vascular endothelial growth factor expression and blood vessel remodelling in pig ovarian follicles during the periovulatory period

Vascular endothelial growth factor (VEGF) expression pattern and blood vessel remodelling were evaluated during the transition from the preovulatory follicle to the corpus luteum (CL). To this end, prepubertal gilts were treated with equine chorionic gonadotrophin (eCG) to collect preovulatory follicles (60 h after eCG) and with human chorionic gonadotrophin (hCG) to obtain periovulatory follicles 18 h and 36 h later. The VEGF mRNA content was analysed by in situ hybridization, while protein localization in follicular fluid (FF) and in granulosa and theca compartments was evaluated by ELISA, immunohistochemistry or western blot. Blood vessel architecture and vascular area (VA) were investigated using immunohistochemistry for von Willenbrand Factor, a specific endothelial marker. Vascular remodelling was finally tested using Ki-67 immunocytochemistry as a proliferation marker, or alpha-smooth muscle actin (alpha-SMA) as a specific mural cell marker. eCG-treated follicles showed high VEGF levels and two concentric blood vessel networks composed of proliferating endothelial cells without any association with mural components. hCG injection inhibited VEGF synthesis in the granulosa compartment and, as a consequence, the protein fell within the FF. In parallel, endothelial cell proliferation stopped and the VA decreased. Close to ovulation, VEGF production restarted in both follicular compartments and VEGF mRNA content significantly increased in the theca layer. Changes in follicular VEGF secretion were observed; the protein disappeared from FF and was observed in the extracellular matrix. An active angiogenesis characterized the follicle; endothelial cell proliferation was associated with a recruitment of alpha-SMA-positive mural cells. The data presented in this work showed that, in the phases preceding ovulation, a complete vascular remodelling occurs, characterized by both an evident neovascularization and the appearance of blood vessels presenting smooth musculature which could be involved in CL formation after ovulation.

Chronic cocaine-mediated changes in non-human primate nucleus accumbens gene expression

Chronic cocaine use elicits changes in the pattern of gene expression within reinforcement-related, dopaminergic regions. cDNA hybridization arrays were used to illuminate cocaine-regulated genes in the nucleus accumbens (NAcc) of non-human primates (Macaca fascicularis; cynomolgus macaque), treated daily with escalating doses of cocaine over one year. Changes seen in mRNA levels by hybridization array analysis were confirmed at the level of protein (via specific immunoblots). Significantly up-regulated genes included: protein kinase A alpha catalytic subunit (PKA(calpha)); cell adhesion tyrosine kinase beta (PYK2); mitogen activated protein kinase kinase 1 (MEK1); and beta-catenin. While some of these changes exist in previously described cocaine-responsive models, others are novel to any model of cocaine use. All of these adaptive responses coexist within a signaling scheme that could account for known inductions of genes(e.g. fos and jun proteins, and cyclic AMP response element binding protein) previously shown to be relevant to cocaine's behavioral actions. The complete data set from this experiment has been posted to the newly created Drug and Alcohol Abuse Array Data Consortium (http://www.arraydata.org) for mining by the general research community.

A cocaine analog, 2beta-propanoyl-3beta-(4-tolyl)-tropane (PTT), reduces tyrosine hydroxylase in the mesolimbic dopamine pathway

Tyrosine hydroxylase (TH) is the rate-limiting enzyme in catecholamine biosynthesis. Previously published results have established that chronic cocaine administration (30-45 mg/kg per day, 10-14 days) resulted in an upregulation of TH gene expression in dopaminergic pathways of rats. The present studies tested the effects of a tropane analog, PTT (2beta-propanoyl-3beta-(4-tolyl)-tropane), on TH expression. This drug has similar actions to cocaine, but possesses markedly different pharmacokinetics (20 times more potent at binding the dopamine transporter, markedly increased metabolic stability, and 10-20 times more potent in behavioral measures). Moreover, PTT demonstrates an increased selectivity for the dopamine (DA) and norepinephrine (NE) transporters compared with cocaine. In direct contrast to the previously reported effects of cocaine, 10 days of PTT administration (3.0 mg/kg per day, i.p.) produced a uniform downregulation of TH protein and activity gene expression. TH activity and immunoreactive protein where decreased by 54 and 69%, respectively in the nucleus accumbens. Within the ventral tegmental area, TH activity and protein were decreased by 33 and 19%, respectively. The underlying mechanisms for these fundamental differences are unclear, but likely reflect varying and selective affinities and lengths of occupancy at biogenic amine transporters.

Nerve growth factor production in sheep antral follicles

Despite their continuous turnover, sheep antral follicles are always regularly innervated. The local production of neurotrophins is probably involved in the control of ovarian innervation. In this context the present investigation was designed to evaluate the ability of sheep antral follicles to produce neurotrophic factors. In the first part of the paper neurotrophic activity was measured in follicular fluid of sheep antral follicles of different size. Using an in vitro model the effect of gonadotrophins on neurotrophin production was then evaluated. The levels of neurotrophic activity in conditioned medium or follicular fluid and the kind of neurotrophin produced were determined by using the chicken embryo dorsal root ganglia test combined with an immunoneutralization step. Follicular fluid from medium-large follicles (>4 mm) contains high levels of NGF (240-250 ng/ml), whereas the factor is nearly undetectable in small follicles (<3 mm) and in early atretic follicles. Experiments in vitro based on the culture of follicle shells for 12 hr confirmed that medium-large follicles can produce NGF. The production is strictly dependent on gonadotrophin stimulation. When gonadotrophins were not added or were added separately, no detectable levels of neurotrophic activity accumulated in medium. By contrast, in the presence of both LH and FSH the production of NGF became apparent showing a clear dose-response behavior. In addition, this production increased progressively with increasing follicle size from 4 to >5 mm up to values of about 60 ng/follicle, whereas follicles with a diameter of less than 3 mm were insensitive to gonadotrophins stimulation and did not produce significant amount of NGF. The data presented demonstrate that sheep follicles produce relevant amounts of NGF as long as the correct hormonal milieu is provided. Under these conditions the production of the NGF increases with increasing follicle size. This may be responsible for the rapid innervation of the wall of growing follicles and/or take part in other non-neural processes that are generally attributed to gonadotrophin stimulation.

Peribulbar anesthesia with either 0.75% ropivacaine or a 2% lidocaine and 0.5% bupivacaine mixture for vitreoretinal surgery: a double-blinded study

No study has evaluated the efficacy of ropivacaine in peribulbar block for ophthalmic surgery. The purpose of this prospective, randomized, double-blinded study was to compare ropivacaine and a lidocaine-bupivacaine mixture in peribulbar anesthesia. Sixty ASA physical status I or II patients scheduled for elective vitreoretinal surgery were randomized to receive a peribulbar block with 8 mL of either 0.75% ropivacaine (ropivacaine group, n = 30) or a 1:1 mixture of 2% plain lidocaine and 0.5% plain bupivacaine (lido-bupivacaine group, n = 30). Time required for onset of surgical anesthesia, quality of postoperative analgesia, incidence of side effects, and analgesic consumption were recorded. Surgical block was achieved after 8 +/- 5 min in the lido-bupivacaine group and after 10 +/- 5 min in the ropivacaine group (P = 0.23). A 3-mL supplemental injection 15 min after block placement was required in 6 patients in the lido-bupivacaine group (20%) and in 10 patients in the ropivacaine group (33%) due to inadequate motor block (P = 0.38). On Postoperative Day 1, 26 patients in the ropivacaine group (87%) reported no pain at the verbal rating score, compared with 18 patients in the lido-bupivacaine group (60%) (P = 0.005). We conclude that 0.75% ropivacaine may be a suitable choice when performing peribulbar anesthesia for vitreoretinal surgery.

IMPLICATIONS

Quick onset of block with prolonged postoperative analgesia is an important goal in regional anesthesia for ophthalmic surgery. Evaluating clinical properties of 0.75% ropivacaine and a 1:1 mixture of 2% lidocaine and 0.5% bupivacaine for peribulbar anesthesia, we demonstrated that ropivacaine has an onset similar to that of the lidocaine-bupivacaine mixture and provides a better quality of postoperative analgesia.

Lightwand intubation does not reduce the increase in intraocular pressure associated with tracheal intubation

OBJECTIVE

To evaluate the changes in hemodynamic variables and intraocular pressure (IOP) after tracheal intubation using either lightwand or direct-vision laryngoscopy techniques.

DESIGN

Prospective, randomized study.

SETTING

Inpatient anesthesia at a University Anesthesia Department.

PATIENTS

50 normotensive, ASA physical status I and II patients, without ocular or cardiovascular diseases, and with a Mallampati score no greater than 2.

INTERVENTIONS

After intravenous (i.v.) midazolam premedication (0.05 mg.kg-1), general anesthesia was induced with fentanyl (1 microgram.g-1) and thiopental sodium (5 mg.g-1) followed by vecuronium bromide (0.1 mg.g-1), then patients were randomly allocated to receive either the lightwand (Trachlight, n = 25) or direct-vision laryngoscopy (Laryngoscopy, n = 25) intubating techniques. General anesthesia was maintained with 1% isoflurane and 60% nitrous oxide in oxygen mixture for 5 minutes.

MEASUREMENTS AND MAIN RESULTS

Baseline hemodynamic variables were recorded 10 minutes after i.v. premedication, and then every minute after tracheal intubation. Intraocular pressure measurements were performed by means of a computerized indentation tonometer after general anesthesia induction and then 1 and 5 minutes after tracheal intubation. In both groups, mean arterial blood pressure and heart rate increased from baseline, without differences between the two groups. One minute after intubation, IOP increased in both groups: the mean percentage increase was 32% in the Laryngoscopy group and 16% in the Trachlight group. However, this difference was not statistically significant. Five minutes after intubation, IOP decreased to baseline values in both groups.

CONCLUSION

We conclude that in healthy patients without ocular disease, using a lightwand intubating technique does not reduce the hemodynamic responses and increase in IOP associated with tracheal intubation as compared with conventional direct-vision laryngoscopy.

Biochemical and biological effects of KN-93, an inhibitor of calmodulin-dependent protein kinase II, on the initial events of mouse egg activation induced by ethanol

Calmodulin-dependent protein kinase II (CaMKII) is transiently activated in mouse eggs by the increase in calcium that occurs upon activation with ethanol. This study investigated the biological and biochemical effects of KN-93, a reported selective inhibitor of CaMKII, to explore the potential role of this kinase in the initial events of egg activation. Mouse eggs were incubated for 30 min in the presence of different concentrations of KN-93 and induced to activate by 7% ethanol. KN-93 elicited a dose-dependent inhibition of polar body emission that resulted from the failure of the eggs to undergo meiosis resumption and inactivation of maturation-promoting factor (MPF). Furthermore, 15 mumol KN-93 l-1 produced a marked reduction in ethanol-induced loss of cortical granules. In vivo biochemical analysis revealed that 15 mumol KN-93 l-1 was responsible for significant inhibition of ethanol-stimulated CaMKII. The activity of the enzyme remained at a resting value, in spite of the presence of a calcium signal similar to that measured in control activated eggs. The inhibitory effects of KN-93 on the parameters tested in this study could not be mimicked by the inactive analogue KN-92. These results show that in mouse eggs, when ethanol-induced CaMKII activation was prevented, cortical granule exocytosis and meiosis resumption were inhibited. This suggests that CaMKII acts as a switch in the transduction of the calcium signal triggering mammalian egg activation.