Clin Neuroradiol (2018) 28:225–234
Regional Diﬀerences in Thrombectomy Rates
Secondary use of Billing Codes in the MIRACUM (Medical Informatics for Research and Care in
University Medicine) Consortium
· Thomas Ganslandt
· Waltraud Pfeilschifter
· Wolf-Dirk Niesen
· Karl Egger
Marc A. Brockmann
· Eva Neumaier-Probst
· Siegfried Bien
· Hans-Ulrich Prokosch
Received: 2 August 2017 / Accepted: 14 December 2017 / Published online: 8 January 2018
© Springer-Verlag GmbH Germany, part of Springer Nature 2018
Background and Purpose Mechanical thrombectomy, in addition to intravenous (i.v.) thrombolysis is recommended for
treatment of acute stroke in patients with large vessel occlusions (LVO) in the anterior circulation up to 6 h after symptom
onset. We compared thrombectomy rates of eight university hospitals of the MIRACUM consortium to analyze the
implementation of this guideline in clinical routine.
Methods Anonymized billing data in a standardized format were loaded into a local i2b2 data warehouse by applying
already existing extract, transform and load (ETL) routines. A locally executed uniform SQL (structured query language)
query delivered aggregated site data for all inpatients with a discharge diagnosis of ischemic stroke (ICD-10 I63) containing
counts for type of acute treatment, type of admission and age groups, which were centrally analyzed with R.
Results From 2014 to 2016, the thrombectomy rate almost doubled from a mean of 4.7% to 9.6%, although signiﬁcant
differences between centers exist (range in 2016: 5.8–17%). The number of drip-and-ship procedures increased in 3 out of
8 centers. There was no evidence for a decrease in thrombectomy rates during weekends/holiday or among patients older
than 80 years, but this age group is more likely to receive i.v. recombinant tissue plasminogen activator (rtPA).
Conclusion The observed increase of thrombectomy rates and drip-and-ship procedures without a signiﬁcant difference
between weekdays and weekends or patients of different ages is substantiating a rapid implementation of stroke guidelines
within the analyzed neurovascular centers. The prototype of the MIRACUM Data Integration Center already contributes
to health services research in Germany.
Keywords Data Warehousing · Infarction · Middle Cerebral Artery · Mechanical Thrombolysis · Thrombolytic Therapy
In Germany, around 260,000 patients suffer a stroke each
year . Most of these patients (approximately 75%) are
treated in one of the approximately 300 stroke units certiﬁed
by the German Stroke Society (DSG) . The DSG distin-
Electronic supplementary material The online version of this
article (https://doi.org/10.1007/s00062-017-0656-y) contains
supplementary material, which is available to authorized users.
Extended author information available on the last page of the
guishes supraregional (38%), regional (58%) and telemed-
ically afﬁliated stroke units (4%). A further development
is the intended certiﬁcation of neurovascular networks .
Among other criteria, neurovascular networks and suprare-
gional stroke units are characterized by the capacity to per-
form mechanical thrombectomy 24 h/7 days.
The i.v. thrombolysis rate is a well-accepted measure of
the quality of care of stroke units. In 2012 it increased to
14% of all acute ischemic strokes in the state of Baden-
Württemberg (Germany) and within the 4.5 h time win-
dow for supraregional stroke units, the rate was as high
as 44% in the period 2008–2012 [4, 5]. After the efﬁ-
cacy of mechanical thrombectomy to improve outcome in
stroke patients with large vessel occlusion (LVO) has been