Abstract 3275: Early Neurological Improvement After Intravenous Thrombolysis in Acute Stroke Predicts Long-Term Functional Outcome

Background: Intravenously administered tissue plasminogen activator (IV-TPA) remains the only approved therapeutic agent for arterial recanalization in acute ischemic stroke (AIS). Wide variations in the rates and timing of neurological recovery are observed in thrombolyzed patients. While all IV-TPA treated patients are routinely evaluated for neurological recovery at 24-hours, considerable improvement occurs in some cases within 2-hours of treatment initiation. We evaluated whether early neurological improvement at 2-hours after IV-TPA bolus (ENI-2) can predict functional outcomes in thrombolyzed AIS patients at 3-months.

Methods: Data for consecutive stroke patients treated with IV-TPA within 4.5 hours of symptom-onset during 2007-2010 were prospectively entered in the thrombolyzed registry maintained at our tertiary care center. Data were collected for demographic characteristics, vascular risk factors, stroke subtypes and blood pressure levels before IV-TPA bolus. National Institute of Health Stroke Scale (NIHSS) scores were obtained before IV-TPA bolus and at 2-hours. ENI-2 was defined as a reduction in NIHSS score by more than 10-points from baseline score or an absolute score of 4-points or less at 2-hours after IV-TPA bolus. Functional outcomes at 3-months were determined by modified Rankin scale (mRS). Data were analyzed by SPSS 19.0.

Results: Of the 2238 AIS patients admitted during the study period, 240 (11%) received IV-TPA within 4.5-hours of symptom-onset. Median age was 65yrs (range 19-92), 63% males, median NIHSS 17points (range 3-35) and median onset-to-treatment time 149 minutes. Overall, 122 (50.8%) patients achieved favorable functional outcome (mRS 0-1) at 3-months. Factors associated with favorable outcome at 3-months on univariable analysis were younger age, female gender, presence of atrial fibrillation, baseline NIHSS, onset-to-treatment time (OTT) and ENI-2. However, multivariable analysis demonstrated NIHSS at onset (OR per 1-point increase 0.907, 95%CI 0.848-0.969) and ENI-2 (OR 4.926 95%CI 1.66-15.15) as independent predictors of favorable outcome at 3-months.

Conclusion: Early Neurological improvement at 2-hours after IV-TPA bolus is a strong predictor of the functional outcome at 3-months in acute ischemic stroke patients.

Current Status of Intravenous Thrombolysis for Acute Ischemic Stroke in Asia

Background

Data regarding thrombolysis for acute ischemic stroke in Asia are scarce and only a small percentage of patients are thrombolysed. The dose of intravenous tissue plasminogen activator (IV-tPA) in Asia remains controversial. Case-controlled observation studies in Asia included only Japanese patients and suggested the clinical efficacy and safety of low-dose IV-tPA (0·6 mg/kg body weight; max 60 mg) comparable to standard dose (0·9 mg/kg body weight; max. 90 mg). Reduced treatment cost, lower symptomatic intracerebral hemorrhage risk and comparable efficacy encouraged many Asian centers to adopt low-dose or even variable-dose IV-tPA regimens. We evaluated various Asian thrombolysis studies and compared with SITS-MOST registry and NINDS trial.

Methods

We included the published studies on acute ischemic stroke thrombolysis in Asia. Unadjusted relative risks and 95% Confidence intervals were calculated for each study. Pooled estimates from random effects models were used because the tests for heterogeneity were significant.

Results

We found only 18 publications regarding acute ischemic stroke thrombolysis in Asia that included total of 9300 patients. Owing to ethnic differences, stroke severity, small number of cases in individual reports, outcome measures and tPA dose regimes, it is difficult to compare these studies. Functional outcomes were almost similar (to Japanese studies) when lower-dose IV-tPA was used in non-Japanese populations across Asia. Interestingly, with standard dose IV-tPA, considerably better functional outcomes were observed, without increasing symptomatic intracerebral hemorrhage rates.

Conclusions

Variable dose regimens of IV-tPA are used across Asia without any reliable or established evidence. Establishing a uniform IV-tPA regimen is essential since the rapid improvements in health-care facilities and public awareness are expected to increase the rates of thrombolysis in Asia.

Brain attack: needing resuscitation

The brain is extremely susceptible to focal ischaemia. Following vascular occlusion, a core of severely damaged brain tissue develops, surrounded by an ischaemic penumbra. This potentially-salvageable penumbra may be estimated by advanced neuroimaging techniques, particularly by diffusion-perfusion mismatch. Clinical trials have demonstrated the efficacy of intravenous thrombolysis within three hours of onset of ischaemic stroke in reducing short-term disability. Recanalisation is enhanced by intra-arterial thrombolysis, sonothrombolysis and clot-retrieval devices. Occasionally, reperfusion injury may lead to clinical deterioration. The search continues for effective neuroprotectants. Brain perfusion needs to be maintained through blood and intracranial pressure management. Hemicraniectomy for 'malignant' cerebral oedema reduces death and disability. Elevated glucose should be controlled and hypoxia alleviated. Public education of symptoms and the need for immediate presentation to a medical facility is needed. Stroke unit care reduces death and disability with little increase in cost. Current evidence supports urgent efforts to resuscitate the brain after stroke.

Chronic brainstem ischemia in subclavian steal syndrome

Subclavian steal syndrome is usually an incidental finding and rarely causes vertebrobasilar ischemia. We present a 58-year-old man who, over six months, experienced progressive slowing in both talking and walking. Cervical duplex sonography revealed severe stenosis of the right subclavian artery; fixed retrograde flow was noted in the right vertebral artery on transcranial Doppler. The hyperemia-ischemia cuff test resulted in considerable reduction in flow velocities in both posterior cerebral arteries. We attributed his slowness to chronic vertebrobasilar ischemia and surgical revascularization was performed. His symptoms subsided immediately after surgery. The improved perfusion in the posterior circulation was demonstrated on technetium-99 hexamethylpropyleneamine oxime single photon-emission CT. Early diagnosis and prompt treatment resulted in an improved quality of life.

Reversed flow in the basilar artery in acute vertebrobasilar ischemia

Acute vertebrobasilar ischemia is a potentially sinister pathology with high mortality and poor functional outcome in survivors. We report the findings of multi-modal assessment (MRI and cerebrovascular ultrasonography) of cerebral hemodynamics in a patient who suffered from acute brainstem infarction with National Institute of Health Stroke Scale (NIHSS) score of 16 points. Our patient demonstrated reversal of blood flow in the basilar artery on the second day of his stroke and this was associated with significant and rapid clinical recovery over the following 2 days (NIHSS score dropped to 4 points). He had recovered completely when seen in the outpatient clinic 3 months later.

Alternatives to transtemporal approach of transcranial Doppler for the detection of right-to-left cardiac shunt

BACKGROUND

Transcranial Doppler (TCD) is reliable and reproducible for the diagnosis of right-to-left cardiac shunts (RLS).

METHODS

Various factors limiting the performance and diagnostic methods of RLS by TCD are discussed.

RESULTS

In patients with insufficient temporal acoustic windows, TCD may still be reliably used to monitor the microembolic signals at various alternative sites. Diagnostic yield of TCD may be further improved and better quantitative assessment of the 'functional potential' of the RLS by optimizing the preparation of the 'air-saline-blood' contrast-mixture, injecting the mixture in controlled body positions and using power M-mode TCD.

CONCLUSIONS

TCD may be used reliably for the detection as well as the quantification of RLS even in patients with insufficient temporal acoustic windows.

Isolated cortical vein thrombosis - the cord sign

Isolated cortical vein thrombosis is an uncommon condition and often difficult to diagnose, both clinically and radiologically. We report a case of a 38 years old man who presented with headache of new onset and clinical examination was unremarkable. The unenhanced brain CT did not reveal any abnormality. In view of unrelenting headache and partial seizures, we performed magnetic resonance imaging (with axial T1, T2 and gradient echo sequences, coronal FLAIR, diffusion weighted imaging as well as Gadolinium contrast-enhanced images) and magnetic resonance venography of the brain that revealed an isolated parietal cortical vein thrombosis with the rarely reported 'cord sign'. We report the clinical and radiological findings in our patient with isolated parietal cortical vein thrombosis.

Role of Multimodal Evaluation of Cerebral Hemodynamics in Selecting Patients with Symptomatic Carotid or Middle Cerebral Artery Steno-occlusive Disease for Revascularization

BACKGROUND

The circle of Willis provides collateral pathways to perfuse the affected vascular territories in patients with severe stenoocclusive disease of major arteries. The collateral perfusion may become insufficient in certain physiological circumstances due to failed vasodilatory reserve and intracranial steal phenomenon, so-called 'Reversed-Robinhood syndrome'. We evaluated cerebral hemodynamics and vasodilatory reserve in patients with symptomatic distal internal carotid (ICA) or middle cerebral artery (MCA) severe steno-occlusive disease.

METHODS

Diagnostic transcranial Doppler (TCD) and TCD-monitoring with voluntary breath-holding according to a standard scanning protocol were performed in patients with severe ICA or MCA steno-occlusive disease. The steal phenomenon was detected as transient, spontaneous, or vasodilatory stimuli-induced velocity reductions in affected arteries at the time of velocity increase in normal vessels. Patients with exhausted vasomotor reactivity and intracranial steal phenomenon during breath-holding were further evaluated by (99)technetium(m)-hexamethyl propylene amine oxime single photon emission computed tomography (HMPAO-SPECT) with acetazolamide challenge.

RESULTS

Sixteen patients (age 27-74 years, 11 men) fulfilled our TCD criteria for exhausted vasomotor reactivity and intracranial steal phenomenon during the standard vasomotor testing by breath holding. Acetazolamide-challenged HMPAO-SPECT demonstrated significant hypoperfusion in 12 patients in affected arterial territories, suggestive of failed vasodilatory reserve. A breath-holding index of ≤0.3 on TCD was associated with an abnormal HMPAO-SPECT with acetazolamide challenge. TCD findings of a breath holding index of ≤0.3 and intracranial steal during the procedure were determinants of a significant abnormality on HMPAO-SPECT with acetazolamide challenge.

CONCLUSION

Multimodal evaluation of cerebral hemodynamics in symptomatic patients with severe steno-occlusive disease of the ICA or MCA is helpful in the identification and quantification of failed vasodilatory reserve. This approach may be useful in selecting patients for possible revascularization procedures.

Skin wrinkling for diagnosing small fibre neuropathy: comparison with epidermal nerve density and sympathetic skin response

OBJECTIVE

To compare simple tests of small nerve fibre function with intraepidermal nerve fibre density (IENFD) in the evaluation of small fibre neuropathy (SFN).

METHODS

Patients with idiopathic SFN of the hands were prospectively studied. Evaluation involved clinical examination, nerve conduction studies, sympathetic skin response (SSR) and skin wrinkling stimulated by water and EMLA (eutectic mixture of local anaesthetics).

RESULTS

Of 21 patients, 16 (76%) had low IENFD, 15 (71%) impaired water-induced wrinkling, 14 (67%) impaired EMLA-induced wrinkling, and nine (43%) abnormal SSR.

CONCLUSIONS

Stimulated skin wrinkling was nearly as sensitive as IENFD in diagnosing SFN, whereas SSR was of less use. Stimulated skin wrinkling is a useful supportive test when IENFD or other tests of small nerve fibre function are not available.

Prevalence of patent foramen ovale in patients with migraine

Cerebral embolization through a PFO is considered to be a possible cause of migraine attack, therefore the size of the PFO and its 'functional potential' should play an important etiological role in migraine. However, this relationship remains complex due to various methodological issues. We have highlighted some of the important issues related to the diagnostic methodology for PFO and the interpretation of the results. Mere detection of the presence of PFO in patients with migraine may not delineate their true relationship for a better understanding and planning a definitive treatment. There is an urgent need for standardizing the diagnostic methods as well as the criteria for the grading the 'functional status' of PFO.