American Heart Association

Monthly Archives: July 2013

Revisiting the rapidly improving stroke symptom (RISS)

Diogo C. Haussen, MD

  • Levine SR
  • Khatri P
  • Broderick JP
  • Grotta JC
  • Kasner SE
  • Kim D. 
  • Review, Historical Context, and Clarifications of the NINDS rt-PA Stroke Trials Exclusion CriteriaPart 1: Rapidly Improving Stroke Symptoms. Stroke. 2013

    A rapidly improving stroke symptom (RISS) is a commonly encountered clinical scenario, which is inherently associated with doubts regarding the possibility of intravenous alteplase (IV t-PA) use. Some patients improve substantially, but partially, and remain with important clinical deficits if untreated. Others recover to a state with minimal deficits, where the risk of IV t-PA would potentially generate a devastating hemorrhagic complication. Therefore, the operationalization of the RISS concept is important in order to maximize the utilization of thrombolysis while maintaining an acceptable risk-benefit ratio.
    The TREAT Task Force provides the readers of Stroke with an insightful and practical report. The authors review the historical context and intent of the original investigators underlying the exclusion of RISS on the NINDS trial and develop a useful and clinically meaningful definition.
    The authors clarify that the original intention in using “RISS” as a contraindication on the NINDS trial was to avoid the unnecessary treatment of TIAs. With this in mind, the conclusion is straightforward: the definition of RISS should be reserved for those who improve to a non-disabling deficit. One should treat a patient that, despite improving, still has a potentially disabling deficit.
    Moreover, the authors reinforce that delays in administering the thrombolytic is unacceptable (monitoring may be performed solely while preparing and administering the drug). Importantly, the role of imaging in establishing tissue at risk (either through vascular imaging or perfusion maps) despite a non-disabling deficit is described as a totally different and much more complex matter.

    Sex-specific associations between systolic blood pressure and the risk of cardiovascular disease

    Jiaying (Jayne) Zhang, MD 

    Peters SAE, Huxley RR, and Woodward M. Comparison of the Sex-Specific Associations Between Systolic BloodPressure and the Risk of Cardiovascular Disease: A Systematic Reviewand Meta-Analysis of 124 Cohort Studies, Including 1.2 Million Individuals. Stroke. 2013

    Hypertension is the leading risk factor for both cardiovascular and cerebrovascular disease worldwide. Previous studies comparing gender differences in the association of systolic blood pressure (SBP) and cardiovascular disease were inconsistent. Since hypertension is such a major risk factor, it is important to find out the potential sex differences of SBP elevation and cardiovascular outcomes from both clinical and public health perspective.

    In this meta-analysis, Peters and colleagues systematically reviewed data from 124 prospective cohort studies with nearly 1.2 million individuals and more than 50,000 stroke and ischemic heart disease events. The authors found systolic blood pressure increments had similar impact on cardiovascular outcomes in both sexes. Accounting for other major cardiovascular risk factors, there was a 15% increased risk of ischemic heart disease and 25% increase risk of stroke for every 10mmHg increment in SBP both genders.
    While the results of this study is not a shocking surprise, the authors do raise another salient point in the discussion that SBP levels are on average higher and rising in low- and middle- income countries compared to high-income countries. This means primary preventive actions to curb hypertension is therefore, of utmost importance in reducing the burden of cardiovascular disease in the future.

    TMS for Aphasia RTC

    Vasileios-Arsenios Lioutas, MD

    Thiel A, Hartmann A, Rubi-Fessen I, Anglade C, Kracht L,Weiduschat, N.Effects of non-invasive brainstimulation on language networks and recovery in earlypoststroke aphasia. Stroke. 2013

    Interventions targeting recovery from poststroke aphasia are important for the affected patients. Several non-invasive methods have been tested, including transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS). The underlying idea is that stimulation of specific cortical areas can modulate neurologic networks involved in human language. More specifically, there is a “shift” of function from the dominant to the non-dominant hemisphere following ischemic damage, a rearrangement that is thought to be detrimental to the language function. It follows that one of the main targets is limitation of this non-efficient shift, either by inhibiting the non-dominant hemisphere or by stimulating the dominant hemisphere.
    In this interesting study, Drs. Tiel, Heiss et al, investigate the applicability of non-invasive brain stimulation in addition to standard speech and language therapy in the early phase of rehabilitation of patients with post-stroke aphasia. They applied inhibitory TMS in the right (non-dominant) posterior inferior frontal gyrus, using clinical as well as functional imaging (PET scan) markers before and after treatment. In addition to proving applicability of the method in a clinical setting the investigators found significant clinical improvement in the group that received TMS. More interestingly, the functional imaging correlate was found to be a “consolidation” of function in the dominant hemisphere; in other words the patients who received treatment, the shift of language function to the non-dominant side was significantly limited, lending support to the basic underlying principle.
    The results are definitely very interesting and encouraging. But some points need to be taken into account: The patient sample was small (30 patients only), limiting the power of the study. For the same reason, subgroup analysis according to aphasia type was not possible; an issue that merits special attention. Additionally, questions regarding the most appropriate timing and duration of treatment are still under investigation. Although the concept of preventing rearrangement of language networks towards the non-dominant hemisphere seems to provide clinically meaningful results, it should be kept in mind that there is evidence for alternative methods, namely Melodic Intonation Therapy, whose success is based in the exact opposite principle: The right hemisphere is recruited, assuming language processing responsibilities that are normally left hemisphere function.
    In summary, the current study is intriguing as a concept and yielded interesting results. However, the neuroplasticity of language neural networks is a very intricate process and further studies are necessary.