American Heart Association

Monthly Archives: April 2015

Type of anesthesia and differences in clinical outcome after intraarterial treatment for ischemic stroke

Rajbeer Singh Sangha, MD 

van den Berg LA, Koelman DLH, Berkhemer OA, Rozeman AD, Fransen PSS, Beumer D, et al. Type of Anesthesia and Differences in Clinical Outcome After Intra-Arterial Treatment for Ischemic Stroke. Stroke. 2015

With the recent trials publishing favorable data for the use of intra-arterial therapy during acute ischemic stroke, the methods utilized during these procedures will come under further scrutiny.  One of the factors that has thought to be associated with changes in outcome and hotly debated is the use of general anesthesia during endovascular therapy.  Previous studies have suggested that patients who do not receive GA have better clinical outcomes.  Some of the factors that have been postulated with the poor outcomes include induction and recovery phases in GA which are stressful and could lead to cardiac arrhythmias and cardiac ischemia. Furthermore inhaled and intravenous (IV) anesthetic agents are known to alter blood carbon dioxide (CO2) and can cause blood pressure shifts that could lead to changes in cerebral autoregulation with decreased cerebral perfusion.  The authors of the MR CLEAN study hypothesize that patients undergoing endovascular therapy will do better without general anesthesia and use the data from the study to conduct a post-hoc analysis.

They conduct a retrospective cohort study in patients from the pre-trial cohort of the Multicenter Randomized Clinical Trial of Endovascular treatment for acute ischemic stroke in the Netherlands (MR CLEAN), which consists of all consecutive patients with AIS treated with IAT in 16 stroke centers in The Netherlands. Out of the 369 patients that were in the registry, 21 were excluded and 348 patients were used for the analysis; 278 patients were treated without GA and 70 patients with GAA total of 82 (82/348(24%)) patients were functionally independent (mRS 0-2) at discharge. Good clinical outcome was seen in 26% (72 /278) of patients in the non-GA group and in 14% (10/70) of patients in the GA group. A higher mortality rate was seen in the GA group (15/70( 21%)) as compared to the non-GA group (46/278 (17%)), however this difference was not statistically significant.  In unadjusted logistic regression analysis, non-GA was significantly associated with good clinical outcome (OR: 2.1, 95% CI 1.02-4.31). After adjusting for pre-specified prognostic factors, the point estimate remained positive, however did not reach statistically significance (OR: 1.9, 95 % CI: 0.89-4.24). 

This retrospective analysis of the MR CLEAN cohort of patients suggests that patients with AIS of the anterior circulation undergoing IAT without general anesthesia have a higher probability of good clinical outcome compared to patients treated with general anesthesia.  These results did not however reach statistical significance and still leaves a lot of room for debate.  Until a randomized clinical trial is not conducted which compares the two modalities we will not have a conclusive answer.  In light of the recent trials and the importance of anesthesia, a multicenter trial should be conducted addressing this question.  It will be also interesting to see the post hoc analysis of the other interventional trials and see if they reach similar conclusions.  

Prediction factors for paroxysmal atrial fibrillation? The results of the TRELAS study

Michelle Christina Johansen, MD

  • Scheitz JF, Erdur H, Haeusler KG, Audebert HJ, Roser M, Laufs U, et al. Insular Cortex Lesions, Cardiac Troponin, and Detection of Previously Unknown Atrial Fibrillation in Acute Ischemic Stroke: Insights From the Troponin Elevation in Acute Ischemic Stroke Study. Stroke. 2015

    Atrial fibrillation (Afib) is a well-documented risk factor for stroke and conversely a history of stroke in the setting of Afib yields a CHADS2 score of 2, necessitating initiation of anticoagulation. 

    With such a well-established causal relationship, attention has turned to diagnosis of paroxysmal atrial fibrillation with the thought that many cryptogenic strokes are falsely labeled and would be cardioembolic with prolonged monitoring. But in an era where quality of care and cost reduction go hand in hand, how far do physicians need to go in order to diagnose Afib? Should we start with a Holter monitor and if so, how long should the device be worn? What about an implantable device recorder? Is the cost justifiable?

    Scheitz et al. take the paroxysmal afib discussion in a different direction through the TRELAS (TRoponin ELevation in Acute ischemic Stroke) study. Their aim was to identify predictors of previously undetected Afib discovered during in-hospital ECG monitoring. They prospectively registered patients with image confirmed acute ischemic stroke (within 72hrs) who were admitted to a tertiary care hospital in Berlin during a two year window. Exclusions were that the patient had never received a diagnosis of Afib and had no evidence of an ST elevation MI, a pacemaker or endocarditis and they had to be ECG monitored for ≥24 hours. At the time of admission labs to include a highly sensitive cardiac troponin T (hs-cTnT) were drawn and a CHADS2 score and CHA2DS2-VASc score was calculated from baseline covariates independent of whether the patient had atrial fibrillation. Imaging was evaluated to assess for the presence of insular cortex involvement as well as the presence of multiple vascular territory lesions.

    The authors registered 1823 patients and analysis was performed on 1228 patients. 114 patients had paroxysmal afib detected during their in hospital stay (median recording time 3 days). The authors performed a multivariable regression analysis in order to probe for variables suitable for an Afib prediction score. In the final analysis, they found that insular cortex strokes as well as higher hs-cTnT were significantly associated with paroxysmal Afib. Older age and history of hypertension was also associated with newly detected cases.

    Interestingly, the former two variable remained independently associated when excluding patients with monitoring less than 1 day or greater than 5 days. When these two variables were added to a regression model, there was significant improvement in the C statistics (decreased variability) as well as improved predictive value compared to a model including the CHADS2-score or CHA2DS2-VASc-score alone.

    The issue tackled by the investigational team is an important one and represents a nearly daily conundrum for the practicing neurologist. As physicians we long for a way to predict who might need prolonged monitoring. So are we to assume then that patients with an unknown etiology and insular strokes need implantable devices? This seems too vague a definition to as yet be of any clinical utility. What about the role of the hs-cTnT? This marker first entered the cardiology community in 2009 and holds great promise in facilitating diagnosis of MI. There has been literature suggesting that higher levels of hs-cTnT has prognostic information indicating a worse mortality and morbidity following stroke. On the other hand, levels are strongly influenced by age and existing structural heart disease making the applicability of this test in these subgroups limited. Regardless, this study is certainly a step in the right direction as physicians desperately need clear guidance on how to respond to cryptogenic stroke, particularly with our aging population and increased possibility of paroxysmal Afib.

    Practice Kind of Makes Perfect

    Ali Saad, MD

    Strbian D, Ahmed N, Wahlgren N, Lees KR, Toni D, Roffe C, et al. Trends in Door-to-Thrombolysis Time in the Safe Implementation of Stroke Thrombolysis Registry: Effect of Center Volume and Duration of Registry Membership. Stroke. 2015

    It seems intuitive that the longer you do a certain process and the more you see of a disease, the better you get at it.

    This study looked at 44,359 patients in the SITS (safe implementation of stroke thrombolysis) registry in Europe from 2002-2011 and questioned whether the year a center joined the registry and the number of patients seen per year correlated with DTN (door to needle time). Mean DTN was 73 min overall. Centers that joined in 2003-2005 had a mean DTN of 68min while those who joined in 2006-2009 had a mean DTN of 72 min. Centers that saw >100 patients also had improved times and this variable actually had a more robust effect than the year the center joined the registry. Centers treating 75-100 patients per year who joined SITS early experienced a drop from 50 minutes in 2003 to 30 minutes in 2008. Although the results are significant, the only centers that saw robust drops in mean DTN were the minority that saw a large number of patients. 

    Limitations of the study include not being able to perform a subgroup analysis of type of stroke center (primary, secondary, tertiary). Only 5 centers saw 100 or more patients per year. The year a center joined the SITS registry may not necessarily correlate with the experience of a center as they may very well have been practicing for years before officially joining. Outcome measures and safety data were also not mentioned. The study is biased in that centers had to opt into the registry on a voluntary basis.

    How does this paper change my practice? If i had a stroke in Europe, I MIGHT (but not necessarily) go to the largest stroke center even it’s a few minutes further away than a smaller one that’s close.