American Heart Association

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Benchmarking Telestroke Proficiency

Abbas Kharal, MD, MPH, and Richa Sharma, MD, MPH

Jagolino-Cole AL, Bozorgui S, Ankrom CM, Bambhroliya AB, Cossey TD, Trevino AD, et al. Benchmarking Telestroke Proficiency: Page-to-Needle Time Among Neurovascular Fellows and Attendings. Stroke. 2017

Telestroke management is built into the curriculum of many vascular neurology fellowships and affords fellows (NVF) the opportunity to achieve proficiency in this modality. This study demonstrates that the page-to-needle time, or PTNT, is higher among NVFs compared to NVAs. As a result, the authors are suggesting that PTNT is a metric of proficiency. Given lower PTNT among NVAs compared to NVFs, there is an assumption that further training may decrease PTNT and, transitively, increase proficiency. As such, there may be a benefit in greater emphasis of dedicated telestroke training during fellowship.

There is an inherent truth in the logic that additional training can result in decreased PTNT just by sheer procedural repetition to learn the logistics of data-gathering by the phone, video, and imaging from an outside institution. However, perhaps the process is also faster for NVAs compared to fellows due to the attendings’ greater body of experiences seeing numerous patients with each stroke syndrome, treating them acutely, and then following the clinical course in the rehabilitation and subacute phase. Thus, proximal care of stroke patients longitudinally may aide in faster decision-making for remote, telestroke patients. Given that most vascular neurology fellowships are only one clinical year, it is thus critical that telestroke training does not supersede rotations, which require direct patient contact throughout the spectrum of the disease, since it is this contact which informs the decision-making process in the practice of telestroke.

By |November 17th, 2017|clinical, health care, outcomes, policy|Comments Off on Benchmarking Telestroke Proficiency

Beyond Drip and Ship: The Role of Baseline Vascular Imaging for Referring Hospitals in Acute Ischemic Stroke Triage for the Endovascular Era

Danny R. Rose, Jr. MD

Boulouis G, Siddiqui K, Lauer A, Charidimou A, Regenhardt R, Viswanathan A, et al.  Immediate Vascular Imaging Needed for Efficient Triage of Patients With Acute Ischemic Stroke Initially Admitted to Nonthrombectomy Centers. Stroke. 2017

The landmark publication of multiple positive endovascular thrombectomy (EVT) trials in 2015 was a pivotal moment for treatment of acute ischemic stroke. The most significant development in acute stroke treatment in the nearly twenty years since the FDA approval of tissue plasminogen activator in 1996 has led to much discussion with respect to improving stroke systems of care to be able to provide this treatment to as many eligible patients as possible. Reflecting this new development in acute stroke treatment, the American Heart Association released a focused update to their guidelines on acute stroke treatment that recommended endovascular therapy be offered to patients who present within 6 hours of last known normal and have a favorable imaging profile and a National Institutes of Health Stroke Scale (NIHSS) of 6 or greater.

Just as the time-sensitive nature of intravenous thrombolytic administration led to the development of prehospital stroke scales and the stroke alert process, the most effective way to triage and treat patients with suspected emergent large vessel occlusions (LVO) amenable to endovascular treatment is a topic of ongoing research and debate. An important facet of this discussion concerns the most effective method to triage and transfer patients with suspected LVO to a thrombectomy-capable stroke center. A cohort by Sarraj et al. presented at the 2017 International Stroke Conference showed comparably good outcomes for patients transferred to thrombectomy-capable centers as compared to patients who presented directly to the facility, suggesting that the “drip and ship” transfer paradigm can be successfully augmented to accommodate endovascular therapy.

By |September 18th, 2017|clinical, health care, outcomes, policy|Comments Off on Beyond Drip and Ship: The Role of Baseline Vascular Imaging for Referring Hospitals in Acute Ischemic Stroke Triage for the Endovascular Era

Low socioeconomic status across age spectrum associated with higher incidence of stroke in adulthood

Low socioeconomic status is associated with a higher incidence risk of stroke in multiple populations worldwide. Although differences in the prevalence and severity of vascular risk factors likely contribute to this disparity, these risks may also be modified by negative socioeconomically driven influences throughout an individual’s lifespan. Becher et al. sought to investigate this further by conducting a case-control study to investigate the contribution of socioeconomic, genetic, and infectious risk factors during childhood, adolescence, and adulthood with respect to the risk of ischemic stroke in adulthood.
The study was nested in a population-based stroke registry in the city of Ludwigshafen, a city in South-West Germany with about 160,000 inhabitants. Patients of Caucasian race-ethnicity ages 18-80 with first-ever ischemic stroke treated at the only stroke unit within the city were compared to age and sex matched controls who were randomly selected from the general population. Patients with prior stroke, myocardial infarction within the last 90 days, dementia or severe communication barriers were excluded. 

Variables that were studied included anthropometric measures, medical history, smoking status, alcohol intake, diet, physical activity and medications. Socioeconomic measures were separated by age group (childhood, up to age 14; adolescence, age 15-25; adulthood,> age 25). Childhood socioeconomic conditions included parents’ occupation (divided into academic, non-academic white collar, blue collar and unskilled labor) during subjects’ childhood as well as living, familial, material and self-estimated financial conditions. For adolescence, highest school degree and professional education was used.  Last, profession, marital status and periods of unemployment were used as conditions for adulthood. Risk scores were calculated prior to analysis by summing scores according to weights chosen a priori based on previous work. Principal component analysis was also performed, as well as classification into tertiles of the summed scores based on distribution in controls. Odds ratio estimates were determined using both univariate and multivariate analyses, with the latter adjusted for known risk factors for stroke and the other life periods. 

A total of 470 subjects agreed to participate in the study and were compared to 809 controls. For childhood conditions, a higher number of siblings (OR=1.48[1.12-1.96]), lack of an own toilet (OR=1.52[1.12-2.05]), and estimated lower family income (OR=2.9[2.18-3.87]) were independently  associated with stroke in multivariate analysis. Lack of vocational training in adolescence (OR=1.93[1.03-3.63]) was independently associated with stroke.  In adulthood, single, divorced or windowed persons (OR=1.63[1.20-2.22]), greater than 6 months of unemployment (OR=1.52[1.05-2.19]) and unskilled last profession (OR=1.99[1.11-3.60]) were independently associated with stroke. In the fully adjusted model (adjusting for age, sex, medical and lifestyle risk factors, and the other life stages), low socioeconomic conditions during childhood (OR=1.77[1.20-2.60]) and adulthood (OR=1.74[1.16-2.60]) were independently associated with stroke risk. Interestingly, adjustment for medical risk factors attenuated the socioeconomic effect in childhood whereas lifestyle risk factors reduced the effect during adolescence and adulthood. When analyzed by stroke subtype, less favorable childhood socioeconomic conditions were associated with a strong risk of large artery stroke (OR=2.13[1.24-3.67]) that was not found for other etiologies of stroke or life stages. 

This study provides an intriguing insight into the impact of various socioeconomic conditions during each stage of life on stroke risk during adulthood. The relatively large number of patients and variety of factors assessed contribute to the strength of the study, although the lack of knowledge about the precise way that socioeconomic conditions affect health makes confounding factors difficult to assess and control. The attenuation of childhood risk after adjustment for medical factors suggests that factors in childhood may be causally linked to the development of known medical risk factors for stroke later in life, and the attenuation of adult risk after adjustment for lifestyle factors suggests that their effects may be independent of medical risk factors. Further study looking at associations with childhood socioeconomic conditions and medical risk factors for stroke could provide further clarity on this issue. The association of low socioeconomic conditions in childhood with large artery strokes may be related to this relationship, as there are many commonalities between medical risk factors for atherogenesis and stroke. The authors’ hypothesis related to chronic systemic inflammation could be further investigated using high-sensitivity CRP values either in a similarly designed study or, ideally, a longitudinal cohort that would track these values over time.   

The racial and geographical homogeneity of the study population limits its generalizability.  Conducting and reviewing similar studies with racially diverse populations in a variety of locations could be helpful in identifying common factors, as there is likely important variation in diet and environmental exposures between low socioeconomic status groups in different regions worldwide. This study and similar studies will be vital in expanding our understanding of how social conditions contribute to stroke risk.

By |January 7th, 2016|health care, outcomes, policy|Comments Off on Low socioeconomic status across age spectrum associated with higher incidence of stroke in adulthood

Randomized trial shows telephone-based comprehensive caregiver education and support can help mood and quality of life for caregivers of stroke survivors

Danny R. Rose, Jr., MD

Bakas T, Austin JK, Habermann B, Jessup NM, McLennon SM, Mitchell PH, et al. Telephone Assessment and Skill-Building Kit for Stroke Caregivers: A Randomized Controlled Clinical Trial. Stroke. 2015

The myriad of challenges that caregivers of stroke survivors face is an under-recognized consequence of stroke that has significant implications on quality of life for both the caregiver and patient. A 2014 American Heart Association scientific statement reviewed the available scientific literature regarding caregiver interventions and recommended individualized programs that combine skill-building with psycho-educational strategies. The variation in studies cited in that report reflect the current lack of evidence with respect to the most effective and feasible approach to implement such an intervention. Bakas et al. sought to investigate the efficacy of the revised Telephone Assessment and Skill-Building Kit (TASK II, a multifaceted caregiver intervention program) by conducting a randomized controlled clinical trial comparing TASK II to a more traditional program, Support and Referral (ISR) strategy, to determine if a more comprehensive intervention improved caregivers’ mood and quality of life. 

A total of 254 stroke caregivers were randomized to either the TASK II group (n=123) or to the ISR comparison group (n=131). Caregivers were deemed appropriate for inclusion if they were the primary caregiver, 21 years of age or older, anticipated providing care for at least one year and were able to participate in the telephone calls and interviews. Caregivers and stroke survivors were excluded if they had severe cognitive issues, severe mental illness or had been hospitalized for alcohol or drug abuse. Demographics between the two groups were similar. Caregivers were primarily women (78.0%, TASK II; 78.6% ISR), about half spouses (48.4%, TASK II; 46.6%, ISR), predominantly White (70.7%, TASK II; 72.1%, ISR), and ranged in age from 22 to 87 years.

Both groups received an information pamphlet from the American Heart Association. Caregivers randomized to the TASK II intervention group also received a resource guide including a checklist addressing caregiver needs regarding finding information, providing physical and instrumental care as well as managing the survivor’s emotions and behaviors. The resource guide also included skill building information for screening for depressive symptoms, maintaining realistic expectations, communicating with healthcare providers as well as stress management for the caregiver and stroke survivor. Both groups received 8 weekly calls from a nurse with a booster call at 12 weeks. Calls to the caregivers in the TASK II group focused on identifying and prioritizing their needs and concerns and using the resources in the resource guide with skill-building strategies. Calls to caregivers in the ISR group focused on providing support through active listening strategies. Baseline data were collected within 8 weeks after the stroke survivor was discharged, and follow-up data were collected at 8 weeks (post-intervention), 12 weeks and at 24 and 52 weeks. Caregiver outcomes were assessed using validated questionnaires on depressive symptoms (Patient Health Questionnaire Depressive Symptom Scale, PHQ-9), changes in social functioning, subjective well-being, and physical health (Bakas Caregiving Outcomes Scale, BCOS), and Unhealthy Days, measured by summing two items asking caregivers to estimate the number of days in the past 30 days that their own physical and/or mental health had been poor.

At baseline, approximately half of the caregivers in each group reported mild to severe depressive symptoms (defined as PHQ-9 ≥ 5). For that subgroup, caregivers in the TASK II group reported a greater reduction in depressive symptoms from baseline to 8 weeks compared to the ISR group (mean difference -2.6, p= 0.013) The effect was also found when comparing baseline to 24 weeks (mean difference -1.9, p=0.041) and baseline to 52 weeks (mean difference -3.0, p=0.041). This subgroup also had a significant improvement in life changes compared to ISR participants from baseline to 12 weeks. This difference was not present for the cohort as a whole for either endpoint. Caregivers in the TASK II group also had a greater reduction in unhealthy days from baseline to 8 weeks compared to the ISR group (mean difference -2.9, p=0.025).

This study represents an important step in the continued effort to design and revise evidence-based programs to provide targeted caretaker support. Based on this study, it appears that caretakers with baseline depressive symptoms are a particularly vulnerable subset that tend to benefit from caregiver interventions in general and do better with interventions targeted at identifying needs and building problem solving skills. It is also worth noting that this represents the first telephone-based intervention showing durable results up to one year for any group of caretakers, and is much more feasible compared to interventions focusing on in-person counseling. Further research on a larger scale resulting from the incorporation of this and similar caregiver well-being intervention strategies into existing stroke systems of care will likely continue to improve our understanding of the most efficient and effective way to provide targeted interventions to improve caretaker well-being

By |December 22nd, 2015|health care, policy|Comments Off on Randomized trial shows telephone-based comprehensive caregiver education and support can help mood and quality of life for caregivers of stroke survivors

What the FAST-MAG Study teaches us about EMS Systems of Care for Acute Stroke

Danny R. Rose, Jr., MD 

Sanossian N, Liebeskind DS, Eckstein M, Starkman S, Stratton S, Pratt FD, et al. Routing Ambulances to Designated Centers Increases Access to Stroke Center Care and Enrollment in Prehospital Research. Stroke. 2015

Patients with acute stroke have better outcomes when treated at organized stroke centers. Emergency Medical Services (EMS) providers play a critical role in the stroke care system by identifying patients with suspected stroke and then providing rapid transport to a facility providing an appropriate level of specialty care. Since 2007, this notion has been reflected in the American Stroke Association guidelines, which recommend Emergency Medical Services (EMS) systems preferentially route acute stroke patients to certified stroke centers that have proven their capability to deliver stroke care. Although this was supported by legislation or regulations in states and counties covering 53% of the US population by 2010, few studies have investigated whether these policies increase access to stroke center care. The impact on research associated with having a greater proportion of acute stroke patients treated at stroke centers, many of which actively enroll patients in clinical trials, is unknown.

Although the FAST-MAG study, a phase 3 clinical trial for prehospital initiation of magnesium vs. placebo for suspected acute stroke patients, failed to show a statistically significant benefit, it proved the feasibility of conducting a trial utilizing prehospital EMS protocols in a large metropolitan area spanning multiple provider agencies. What makes this study unique was that it was carried out in Los Angeles County over a period that in which there was a substantial change in the way EMS routed patients due to the implementation of a regional system of stroke care. Sanossian et al. performed an analysis using data from this study to investigate how the implementation of preferential routing for acute stroke patients impacted Emergency Department arrival times, the percentage of patients treated at an acute stroke center, and the numbers of patients enrolled in this prehospital stroke study. 

A total of 1627 subjects were enrolled in Los Angeles County over the course of the study, with 863 (53%) prior to and 764 (47%) after adoption of the countywide EMS routing protocol. In the nearly 5 years prior to EMS routing, only 90/863 (10%) of patients were transported to a designated Primary Stroke Center (PSC). EMS routing increased this proportion dramatically, with 698/764 (91%) of patients enrolled after the protocol implementation (P<0.001). Interestingly, the time from EMS arrival on scene to ED arrival actually decreased slightly after the routing change (34.5 min. vs 33.5, p=0.045). An analysis focused on the years immediately before and after the stroke center diversion policy was implemented showed an equally impressive improvement in the percentage of patients transported to PSCs (17% vs. 88%, P<0.0001), shorter scene to door times (33.6 min. vs 34.5, p=0.221), and a greater mean monthly enrollment into the FAST-MAG study (21.2 vs 17.9 subjects per month)

The analysis illustrates the dramatic effect that a properly implemented policy can have on improving the proportion of suspected acute stroke patients treated at stroke centers without detrimentally affecting transport times, one of the most common concerns regarding these types of changes. As these and similar changes designed to ensure acute stroke patients are preferentially treated at Joint Commission-certified stroke centers are implemented, there will likely be benefits beyond the more efficient conduct of clinical trials.

There, however, are significant limitations to the study that affect its generalizability. As in most major metropolitan areas in the US, Los Angeles County has a large amount of adult ED receiving facilities in a relatively small geographic area, with a total of 69 facilities participating in this study. The proportion of these facilities that obtained PSC certification increased steadily throughout the course of the trial, from 9 at the initiation of the routing policy in 2009 to a total of 29 by the trial end in December 2012. Although this can serve as a useful model for other major metropolitan areas in the US, access to primary stroke centers is more limited in large portions of the country. In these areas, routing suspected stroke patients exclusively to stroke centers could result in important delays in evaluation and treatment. This should not discourage policymakers in rural areas from adopting protocols to ensure acute stroke patients are triaged and transported efficiently. In these relatively underserved areas, collaboration and cooperation between stroke centers and critical access hospitals will likely remain a crucial component of stroke systems of care as medical infrastructure continues to evolve and mature.

By |September 21st, 2015|health care, outcomes, policy|Comments Off on What the FAST-MAG Study teaches us about EMS Systems of Care for Acute Stroke

On developing multi-national acute stroke care quality measures

Neal S. Parikh, MD   

Norrving B, Bray BD, Asplund K, Heuschmann P, Langhorne P, Rudd AG, et al. Cross-National Key Performance Measures of the Quality of Acute Stroke Care in Western Europe. Stroke. 2015 

In this issue of Stroke, representatives from the European Implementation Score Collaboration describe the process and results of an effort to establish common acute stroke care quality measures.

In order to compare quality measures across nations and regions in Western Europe, the collaborators convened to establish agreed-upon metrics. Physician and patient representatives from multiple Western European nations met to establish two tiers of indicators: Tier I – essential, Tier 2 – desirable. The European Stroke Organization endorsed the final measures.

Table 2 summarizes the 30 performance measures of acute stroke care formulated by this group. There are a number of limitations. The measures include basic patient characteristics, but not patients’ basic vascular risk factors, the omission of which limits the ability to make adjusted comparisons across nations. Additionally, while the measures are grossly in concordance with current evidence, they are non-specific. For example, the duration of cardiac arrhythmia detection and the nature of anti-platelet therapy (mono or dual) are not specified. Finally, the outcome measures are rudimentary: 90 day mortality and modified Rankin Scale. These limitations are anticipated given the variability in resources across nations. The authors also admit that the guidelines cannot keep up with research; for example, provision of endovascular therapy is not included in their quality measures.

Given rapidly mounting evidence regarding high-impact stroke treatment and secondary prevention interventions, it is necessary to document acute stroke management quality measures to ultimately facilitate higher levels of evidence-based stroke care. Efforts such as these are important as quality measures may reveal disparities and thereby inform the decisions of policy-makers and funding organizations. Additionally, these quality measures may serve as a model for other nations.

By |September 18th, 2015|health care, outcomes, policy|Comments Off on On developing multi-national acute stroke care quality measures

The intransient effects of a stroke are borne by many

In this issue of Stroke, Persson and colleagues seek to establish the long-term impact of stroke on a stroke survivor’s spouse. They ask whether a patient’s stroke impacts his or her spouse beyond the short-term or if perhaps improvements in a patient’s stroke deficits or the general adaptability of the human spirit attenuate the consequences for the spouse over the long-term.

They derived their cohort from a Swedish ischemic stroke study that enrolled 600 consecutive patients under the age of 70 with ischemic stroke. After seven years, spouses of stroke survivors and age- and sex-matched controls were identified for comparison. The unit of analysis was survivor and spouse dyad and control and spouse dyad. 248 stroke survivor and 245 control dyads were included after excluding stroke survivors who had deceased or become single. Importantly, those who were excluded had greater disability at 3 months than those who were included. The outcome was self-reported health-related quality of life measured by the multidimensional Short Form 36 tool after controlling for multiple demographic and stroke outcome variables.

Notably, the median NIHSS for stroke survivors had been zero and the median mRS had been only 2. Regardless, even after 7 years, spouses of stroke survivors suffered significantly lower health in multiple domains as compared to spouses of controls. Attributes of the stroke survivor that predicted poor spousal health included the survivor’s levels of disability, depression and cognitive impairment. Perceived lack of social support also predicted poorer spousal mental and emotional health.

It is surprising that minor strokes in young persons with relatively good functional outcomes lead to persistent spousal health consequences. Patients who have strokes before 70 likely have predisposing vascular risk factors (some of which, such as diabetes, can require continued, laborious management) that may be responsible for this study’s findings; there is possible significant residual confounding as the dyads are only matched for age and sex.

If we are to believe the findings, it is worth noting that Sweden has a nationalized healthcare system with near universal coverage, excellent literacy and a high GDP per capita. Extrapolating their findings to developing nations where healthcare and social resources are scant underscores the importance of stroke prevention.

Mechanical thrombectomy for stroke is cost-effective, but scalability remains an issue.

Neal S. Parikh, MD

Ganesalingam J, Pizzo E, Morris S, Sunderland T, Ames D, and Lobotesis K. Cost-Utility Analysis of Mechanical Thrombectomy Using Stent Retrievers in Acute Ischemic Stroke. Stroke. 2015

Five large, randomized clinical trials recently demonstrated that mechanical thrombectomy (MT) significantly reduces disability and mortality in patients presenting with proximal large vessel occlusions. MT is performed after IV-tPA administration or, when IV-tPA is contraindicated, as the sole intervention. In this issue of Stroke, Ganesalingam and colleagues seek to determine whether adjunctive MT for stroke is cost-effective, as compared to IV-tPA alone.

Data from the MT trials were used to determine the proportion of patients expected to achieve three functional categories (independent, dependent and deceased). These data were then run through a long-run Markov state-transition model to estimate the costs and outcomes over 20 years. The Markov model was transformed every 3 months over 20 years, which means patients in the independent (mRS 0,1,2) category were given the ability to have a recurrent stroke and change to any of the three states. The model utilizes cost data from the United Kingdom’s National Health Services (NHS): the cost of TPA was $2,953, the cost of MT was $13,803. The model makes a reasonable, evidence-based assumption that functional outcome correlates with quality adjusted life years (QALYs). Cost effectiveness was determined by assessing the incremental cost per gained QALY and the Net Monetary Benefits (NMB) of adjunctive MT over IV-tPA alone. NHS thresholds for willingness to pay per QALY were utilized: $33,000-$49,500.

The incremental cost of MT over IV-tPA alone was $11,651 per QALY gained. The NMB was below even the lower willingness to pay thresholds. Varying the cost of MT up to $33,000 and the utility of functional independence did not negate the results.

Given the meaningful clinical impact of MT on disability and death and the cost-effectiveness of the therapy, it is imperative that the treatment be made available to more patients. The therapy will become more cost-effective with improvements in stroke referral networks, technology and futile inter-hospital transfer rates (1). However, propagation of MT will face costly infrastructure challenges, as, even under optimal modeling, access to comprehensive stroke centers is limited in the United States (2). It would be worthwhile to assess the comparative and cost effectiveness of directed stroke prevention as compared to stroke treatment infrastructure development.

(1) Fuentes, et al. Futile interhospital transfer for endovascular treatment in acute ischemic stroke. Stroke. 2015;46:2156-2161.
(2) Mullen, et al. Optimization modeling to maximize population access to comprehensive stroke centers. Neurology. 2015;84:1196-1205.

By |August 14th, 2015|health care, outcomes, policy|Comments Off on Mechanical thrombectomy for stroke is cost-effective, but scalability remains an issue.

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.

By |April 1st, 2015|health care, outcomes, policy|Comments Off on Practice Kind of Makes Perfect

Subclinical infarction post cardiac surgery: What’s the damage?

The disability that results from acute infarction is easier to recognize and treat when the patient presents with clear physical sequela of stroke. The impact of subclinical infarction is an understudied area and thus the treating physician lacks clear guidance. Neurologists are all too familiar with ordering head imaging and discovering evidence of prior ischemic insult with the patient denying history of an acute event. What is the physician to do with this information? As our population ages, one can expect that this will become a more common occurrence. More procedures, such as cardiac surgery are also being performed in the latter years. This provides an excellent backdrop upon which to investigate the sequela of accumulating new subclinical infarcts post procedure in those with pre-existing cerebrovascular disease. 

Patel et al. used rapidly evolving technology, the 3T MRI, to assess for new lesions following cardiac surgery, quantified against levels of pre-existing cerebrovascular disease, and also compared neuropsychological testing conducted at identical time intervals. Patients undergoing either a CABG and/or valve surgery at the University of Leicester were eligible for inclusion. Only those who had contraindication to MRI or were not native English speakers were excluded. 3mm 3T MRI images were obtained at intervals 1-2 weeks prior to surgery as well as 6-8 weeks postoperatively. Neuropsychological evaluation with standard battery assessments occurred at the same time intervals. Acute or chronic ischemic change was determined by comparing the DWI and FLAIR sequences by a blinded neuroradiologist. Chronic ischemic change was characterized using a computer program which looked at location and volume of the lesions. Patient cognitive improvement or decline was indicated by a change in the Z score which incorporated the mean and standard deviation from a healthy population.

77 of the 103 patients enrolled successfully completed pre/post-operative MRI and cognitive assessments. FLAIR signal change was found in 49 patients pre procedure. New FLAIR lesions were identified in 24 patients (9 with >1) post procedure with the majority occurring in the MCA territory. There were no baseline characteristics that differed between those with new lesions after cardiac surgery and those without. 22/24 with new lesions had evidence of prior FLAIR signal change. Volume comparison suggested that the accumulation of lesions following surgery is relatively minor (0.004%) in comparison with pre-existing burden (0.1%) due to chronic cerebrovascular disease. Of the 35 patients who showed a decline >1SD in neuropsychological testing following surgery, the majority (24) had NO NEW postoperative lesions. The incidence of cognitive decline (46%) was therefore irrespective of presence, number or size of new lesions. 5 patients notably had acute perioperative stroke but only one patient showed decline in cognition following the procedure.

What conclusions is the practicing neurologist to draw? The good news is that lesions accumulated post cardiac procedure found on imaging appears to have no impact on a patient’s cognition. However, the authors show that patients with pre-existing lesions were ten times more likely to experience new lesions post-operatively. While we may not fully understand the impact of these subclinical lesions, it does confirm what we know to be true. There must be something about the patient population with silent ischemic disease that predisposes them to further insult making prevention all the more important.

By |February 18th, 2015|health care, outcomes, policy|Comments Off on Subclinical infarction post cardiac surgery: What’s the damage?