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Abstract
Background and purpose Despite numerous optimization attempts, time delays are still a relevant problem in endovascular stroke treatment. We hypothesized that public display of the fastest procedural times in our institution would raise awareness, which would result in improved procedural times.
Methods We established a competition, which lasted 6 months, in which the fastest neurovascular team in terms of procedural times (image to reperfusion) was displayed on a public board in our institution and rewarded with public praise. During this time no other relevant procedural or infrastructural means for improvement of procedural times were introduced in our institution. We prospectively evaluated procedural times in 496 patients who received endovascular stroke treatment 9 months before the competition, during the competition, and during the four 6-month time periods for 2 years after the competition.
Results Median image-to-reperfusion times improved significantly from 98 min before the competition to 85 min during the competition (p=0.005) and remained stable with a median of 81 min 2 years after the competition (p=0.837).
Conclusion We were able to improve our procedural times significantly with a simple and cost-efficient competition. This effect was sustained 2 years after the competition was completed, implying that the improvement in procedural times was probably due to raised awareness.
- stroke
- thrombectomy
- balloon
- blood flow
- embolic
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Introduction
The diagnostic and therapeutic chain of endovascular stroke treatment is complex and carries the risk of time delays. As outcome is time dependent, optimization of procedural times is an important goal.1–3 The vast majority of studies have focused on infrastructural or organizational aspects such as the introduction of standardized documentation and standardization and optimization of workflow to ensure faster treatment.4–8 An approach that has not been addressed yet is extrinsic motivation, which can be money but also recognition, praise, or compulsion.9 Common examples are incentive schemes such as the ‘employee of the month award’ in the service sector. Such incentives are uncommon in the medical field, probably because it is expected that intrinsic motivation is a main driver of medical stakeholders.
We hypothesized that a competitive environment with a public display of the fastest neurovascular team would serve as an extrinsic motivation and result in faster procedural times. We established a competition in which the fastest neurovascular team (including interventionalists and technicians) was publicly displayed on a board in our institution and rewarded with a symbolic trophy at the end of the year. We then evaluated the short-term and long-term effects of our incentive up to 2 years after the competition.
Methods
Our hospital is a tertiary stroke center with a catchment area of approximately 1.2 million inhabitants. Approximately 1400 acute ischemic stroke patients are admitted for acute reperfusion therapy each year. Interventional stroke treatment in our hospital is ensured 24 hours a day and 7 days a week by a neurological stroke team that is on site for 24 hours a day and an interventional team that is on site during working hours and on call (with less than 30 min between call and arrival in the hospital) the rest of the time. Before arrival of the patients, the neurologist in charge is informed about a possible stroke by the rescue coordination center and the neurologist informs the neuroradiologist in charge about the case. If a short clinical examination confirms stroke, the anaesthesiologist in charge is also informed and the patient is transferred to the CT suite where the interdisciplinary decision for further treatment is made. Our standard diagnostic stroke protocol consists of cranial CT imaging, CT angiography, and CT perfusion imaging. All interventions are performed under general anesthesia. All medical personnel in our department (technicians and clinicians) participate in diagnostic and interventional neuroradiology and team members change regularly, depending on daily rotations. Neuroradiological facilities (CT, MRI, angiography suite) are located approximately 5 min away from the interdisciplinary emergency room.
Data were derived from our prospectively maintained stroke registry, which was approved by our local ethics committee. The need for patient consent for this analysis was waived.
Patients were selected for endovascular stroke treatment and were treated as reported previously.10 We included all 497 consecutive stroke patients in whom we initiated endovascular stroke treatment for large vessel occlusion stroke (anterior and posterior circulation) in our institution between June 2014 and August 2017. We excluded one patient for whom no sufficient documentation of procedural times was available, which left 496 patients for inclusion in our analysis. For our analysis we included patients before and after the competition and defined observation intervals as follows: 9 months before the competition (June 2014 to February 2015); 6 months during the competition (March 2015 to August 2015); and 6-month time intervals up to 2 years after the competition (until August 2017). In the course of our competition the fastest neurovascular team was publicly displayed on a board and rewarded with a symbolic trophy at the end of the year. The board was located in our institution’s hall, opposite the angiography suite, and displayed the three best times. Slow procedural times were not displayed but they were regularly discussed in our daily debriefings, which was already the case before the competition.
Clinical, procedural, and radiological data
Door-to-image time was defined as the time between the documented time of admission to the emergency department and completion of the first cerebral imaging with CT or MRI. Image-to-puncture time was defined as the time between completion of the first cerebral imaging with CT or MRI to puncture in the angiography suite. Puncture-to-reperfusion time was defined as the time between puncture in the angiography suite and first reperfusion of the affected vessel (Thrombolysis in Cerebral Infarction (TICI) ≥2a). We excluded procedural times from statistical analyses after checking for plausibility; for example, we excluded door-to-image times for in-hospital stroke patients or puncture-to-reperfusion times for patients in whom endovascular stroke treatment was initiated but not finalized because the first digital subtraction angiogram showed that the formerly occluded vessel was revascularized.
Primary outcome measures were in-hospital procedural times. Secondary outcome measures were reperfusion results (TICI) and clinical outcome (modified Rankin Scale (mRS) score at 90 days).
Statistical analysis
We used the Mann–Whitney U test for the comparison of non-parametric continuous data after testing for normal distribution with a Shapiro–Wilk test. P values with an alpha level <0.05 were defined as significant. All statistical analyses were performed with SPSS 25 (IBM, Armonk, New York, USA). The data supporting the findings of this study are available from the corresponding author on reasonable request.
Results
The mean age of the patients was 75±15 years and 50% (248/496) were women. Four hundred and thirty-three of the 496 patients (87%) had a stroke in the anterior circulation. All procedural times improved during the stroke competition (table 1 and figure 1). This effect was significant for all procedural times (p≤0.005) except for the imaging-to-puncture time, which improved by 5 min without reaching statistical significance (p=0.953). In particular, image-to-reperfusion time, which is a good marker for neuroradiological workflow, was significantly reduced (p=0.005). The competition resulted in a reduction in the variance of procedural times (figure 1). During the whole observation period after the competition, median procedural times remained faster than before the competition and never became significantly slower than during the competition (table 1).
Scatter plot diagram illustrating imaging-to-reperfusion time spans over time. Three outliers above 300 min (two before the competition: 677 min and 338 min; and one during the competition: 529 min) were excluded from this graph for visualization purposes. The beginning of the competition is defined as day 0.
Outcome measures (time intervals indicated as median)
There was no immediate improvement in TICI scores (p=0.125) and 90-day mRS scores (p=0.918) during the competition. Complete reperfusion rates and favorable clinical outcome rates improved over time, reaching statistical significance (p=0.001 and p=0.031, respectively) in the last observation period (table 1).
Discussion
With the introduction of the competition, we investigated whether a competitive environment and public display of procedural times can improve procedural times. During our competition we significantly reduced the image-to-reperfusion time, which is a good marker for neuroradiological workflow, and we achieved procedural times that are below the reported median and average times in the literature.11 We were surprised to observe a sustained effect during a period of 2 years after the competition was over, because the literature suggests that extrinsic motivation only has a short-term effect which will usually not last for several months or years.12 13 Hence, our data imply that the long-term improvement was not solely attributed to extrinsic motivation due to the competitive environment. The two most reasonable explanations other than extrinsic motivation are (1) raised awareness of the clinical significance of fast procedural times and (2) a learning process. While a learning process certainly has an impact on continuous improvement of procedural times, we surmise that the significant reduction in procedural times after the introduction of the competition can probably be attributed to raised awareness of the clinical significance of fast procedural times. This is also supported by the fact that the door-to-image time span became significantly shorter, as this period is primarily influenced by the work of the neurology and emergency departments, which did not participate in the competition. Hence, we hypothesize that improvement in our procedural times was due to raised awareness of the clinical significance of fast procedural times rather than extrinsic motivation.
Door-to-image time
The first intrahospital part of stroke therapy includes the period between admission and imaging (door-to-image time), which depends on the workflow of the emergency and neurological departments. Improvements in this period have been achieved mainly with workflow optimization such as the introduction of uniform imaging protocols.14 15 According to the HERMES (Highly Effective Reperfusion evaluated in Multiple Endovascular Stroke trials) meta-analysis, 50% of patients go through this stage within 19 min.11 The median door-to-image time in our cohort decreased from 22 min before the competition to 19 min during the competition, but was never faster than 19 min. We surmise that hard limiting factors, such as the distance between our emergency department and our CT suite (seven floors), prevent us from improving this interval much further. Also, there are clinical limiting factors such as a considerable variation in patients in whom pre-imaging investigation takes longer, such as patients with unstable cardiovascular conditions or those with language barriers.
Imaging-to-puncture time
The phase from imaging to puncture is generally the longest and covers finalization and interpretation of imaging up to the initiation of the intervention. This time frame is characterized by hard limiting factors such as the duration of CT protocols (approximately 6 min for cranial CT, CT angiography, and CT perfusion in our institution), transport between the CT suite and angiography suite, and initiation of general anesthesia or conscious sedation. This is why improvements of this time frame are particularly difficult. As it is possible that intubation takes longer than conscious sedation, an effective measure would be to perform thrombectomies under conscious sedation instead of general anesthesia. However, the decision on whether conscious sedation or general anesthesia is used also depends on many other factors such as patient safety or the interventionalist’s preference.16 It has been shown that a measure to improve this procedural time regardless of type of anesthesia is (1) raising awareness by extensive documentation of procedural times and (2) workflow optimization with early notification of the anesthesiologist and parallel workflow with the interventionalist performing the groin puncture while the anesthesiologist intubates the patient.6 17 The median image-to-puncture time in the HERMES analysis was 76 min.18 At the best 25% of centers with high volumes and an established resource infrastructure, this is expected to be achieved in 51 min or less.11 We improved this time from a median of 44 min to 39 min, although this difference did not reach statistical significance probably because our baseline value before the competition was already fast.
Puncture-to-reperfusion time
This time frame is mainly determined by the actual neurointervention, which is dependent on anatomy, occlusion site, thrombectomy technique, and the skill of the interventionalist. The median puncture-to-reperfusion time in the HERMES analysis was 44 min.11 We reduced this time frame from a median of 54.5 min to 36.5 min, which corresponds to a reduction of 33%. This was slightly and non-significantly reduced further to a median of 33 min 2 years after the competition, which may be attributed to an additional learning effect and an improvement in the thrombectomy technique.
Secondary outcome measures
When we shifted our focus to faster procedural times we were worried that this could result in worse reperfusion results. However, TICI scores, which are a good measure of the quality of thrombectomy, did not deteriorate despite the significant increase in speed. In fact, there was a gradual and significant improvement in TICI scores, which is likely due to improved thrombectomy technique but also supports the hypothesis of a long-term learning effect. Notably, our improved procedural times did not immediately result in improved clinical outcome. Given that procedural times were already fast before the competition, other factors such as patient selection (we include patients with multiple morbidities and very low ASPECT scores) and thrombectomy technique (we modified our technique from using large-bore sheaths to balloon guide catheters for carotid access) appear to have an equally important impact on clinical outcome.19
Limitations of the study
The major limitation of our study is that our specific clinical environment is not a standardized test environment. Hence, we cannot fully elucidate the exact causes for improvement in procedural times and our results may not be easily transferable to other hospitals.
Conclusions
We have shown that establishing a competitive environment and publicly presenting and discussing procedural times is an effective and cost-efficient way to improve procedural times. This improvement was sustained for 2 years after the competition, implying that this effect was probably due to raised awareness.
Acknowledgments
The authors would like to thank Nina Cryns and Johanna Leinders for their invaluable support during data acquisition.
References
Footnotes
Contributors Conception and design: all authors. Acquisition of data: all authors. Analysis and interpretation of data: all authors. Drafting the original article: JM. Critically revising the article: all authors.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial, or not-for-profit sectors.
Competing interests MW: Consultancy: Stryker. Payment for lectures: Bracco, Medtronic, Siemens, Stryker. Payment for development of educational presentations: Bracco, Codman, Medtronic, Phenox, Siemens.
Provenance and peer review Not commissioned; externally peer reviewed.
Patient consent for publication Not required.