Development of a Clinical Decision Support System for Improving the Acute Care Process of Stroke Patients Based on Clinical Variables Master thesis in medicine Ludvig Valentin-Askman 8 dec 2015 Background Hemorrhagic stroke (ca 13 %) VS. Ischemic stroke (ca 87 %) 8 dec 2015 Background • Stroke Subtyping Scoring Systems used for differentiation between hemorrhage and ischemia • For prehospital triage of stroke patients? 8 dec 2015 Aim • Provide data for development of a clinical decision support system for stroke patients through literature review • Interviews with clinical expertise • Construct a draft! 8 dec 2015 Results Nine identified Stroke Subtyping Scoring Systems differentiating between HS and IS 8 dec 2015 The Allen Score (1983) • London, U.K. • prospective for variable derivation, validation in same population • 165 patients (136 IS, 29 HS, all >74 years) • Reference test CT or autopsy • Requires 24 h observation 8 dec 2015 The study derived eight clinical variables from a patient material consisting of 165 patients presenting with acute stroke and consecutively recruited upon admission (14). Discriminant coefficent values were calculated for the variables, resulting in a value that separates patients into two groups. Variables used in the Allen score are shown in Table 6, along with clinical features. Notably, the score is constructed for observation of patients at least 24 hours from admission. Table 6: Variables included in the Allen score, and their interpretation in terms of clinical features (14) Variable Clinical feature Apoplectic onset •! One!or!none!of!these! a)! Loss!of!consciousness! •! Two!or!more! b)! Headache!within!2!h! c)! Vomiting!! d)! Neck!stiffness! Level of consciousness (24 h after admission) •! Alert! •! Drowsy! •! Unconscious! Plantar response •! Both!flexor/single!extensor! •! Both!extensor! Diastolic blood pressure (24 h after admission) Blood pressure in mm Hg Atheroma markers (angina, claudication, •! Not!present! diabetes history) •! One!or!more! History of hypertension •! Not!present! •! Present! Previous event (TIA or stroke) •! None!! •! Any!number!of!previous!events! Heart disease •! None! •! Aortic!or!mitrAl!murmur! •! Cardiac!failure! •! Cardiomyopathy! •! AtriAl!fibrillAtion! •! Cardiomegaly!(Chest!radiograph)! •! MyocArdiAl!infArction!within!six! months! TIA= Transient Ischemic Attack Variable Validation • CorrectWhen physiciansdiagnosis were inasked 148/165 to clinically patients diagnose study patients as IS or HS without using the score, correct diagnosis was obtained in 138/165 patients, whereas the Allen score correctly8 dec 2015 diagnosed 148/165 patients (p=0.078) (14). For six patients the score indicated IS as the most likely ! 12! The Siriraj Score (1991) • Bangkok, Thailand • Prospective • Acute supratentorial stroke • Excluded subarachnoid hemorrhage, brain stem or cerebellary stroke • 174 patients for variable derivation, 206 for validation • Reference test CT 8 dec 2015 etiology, although CT-scan revealed HS. Four of these had small deep hematomas and two had peripheral hematomas where investigation revealed partly hemorrhagic infarctions. ! 6.1.2 The Siriraj Score Table 7: Data for the Siriraj Score Introduction year 1991 Introduction location Bangkok, Thailand Design Prospective Included etiologies Acute supratentorial stroke Exclusion criterias Subarachnoid hemorrhage, brain stem or cerebellary stroke. Patient selection Consecutive recruitment Patient characteristics 174 for variable derivation, 206 for validation Reference test CT-scan (all patients examined within 72 hours from onset) CT= Computed Tomography Variable Derivation The Siriraj stroke score was proposed with the ambition to differentiate between HS and IS in supratentorial stroke syndromes (e.g. within the left or right hemisphere). Upon admission to hospital 13 variables were recorded. The Siriraj score include five variables which were found to differ significantly between IS patients and HS patients. Table 8: Variables and interpretation in the Siriraj score for differentation between IS and HS (15) Variable Interpretation Level of consciousness Alert= 0p, drowsy= 1p, semicoma/coma= 2p Vomiting No= 0p, yes= 1p VariableHeadache Validation within 2h No= 0p, yes= 1p Diastolic blood pressure - DuringAtheroma validation, markers the(history score of achieveddiabetes, angina, a sensitivity or forNone= HS of0p, 89.3% one or more=and sensitivity 1p for IS of intermittent claudication) 93.2%IS= Ischemic (15) .Stroke, The overall HS= Hemorrhagic predictive Stroke accuracy was 90.3% during validation, as 149/165 patients were Formula 4: Calculation of the Siriraj Stroke Score (15) correctly diagnosed. 41 patients recieved scores between the cut off values, and were therefore not CDEDEFG&HIEJKL&HMJEL = 2.5&×&QLRLQ&JS&MJTHMDJUHTLHH + 2&×&RJVDIDTW + 2&×&ℎLFYFMℎL&ZDIℎDT&2&ℎJUEH diagnosed by the score, nor were they included in the calculation of score performance. + 0.1&×&YDFHIJQDM&]QJJY&^ELHHUEL − 3&×&FIℎLEJVF&VFEKLEH − &12 Cut off points were identified, resulting in the optimal differentiation of the IS group and the HS Table 9: Score distribution for the hemorrhagic stroke group and the ischemic stroke group in validation study (15) Score HS (n=142) IS (n=64) group.< -1 If the score is >1, HS is the most likely etiology,13 whereas a score <-1 indicates41 IS. Values >-1, <1 21 20 between>1 cut off points will remain undiagnosed. 108 3 HS= Hemorrhagic Stroke, IS= Ischemic Stroke 6.1.3 The Besson Score ! 13! 41 patients with equivocal scores! Table 10: Data for the Besson Score Introduction year 1995 8 dec 2015 Introduction Centre Hospitalier Universitaire de Grenoble, Grenoble, France location Design Prospective Included Stroke symptoms >24h, with at least unilateral motor weakness in face and/or arm and/or leg etiologies Exclusion Bilateral motor weakness, anticoagulant therapy criterias Patient selection Consecutive recruitment Patient 368 (209 men, 159 women, median 72 years, range 21-97 years, 305 IS, 63 HS) for variable characteristics derivation. 200 (122 men, 78 women, median 72 years, range 27-95 years, 167 IS, 33 HS) for validation Reference test CT-scan (within 24h) IS= Ischemic Stroke, HS= Hemorrhagic Stroke, CT= Computed Tomography Variable Derivation The Besson score was proposed with the aim to develop a simple SSSS for distinguishing IS from HS with Positive Predictive Value (PPV) close to 100 %. The PPV is the probability of disease when the test indicates disease, whereas the Negative Predictive Value (NPV) is the probability of no disease when the test indicates no disease (16). The Besson score was designed for prehospital use. The aim was not to classify all strokes, but rather to identify patients with IS. As a result of this, NPV has not been included in this study as an indication of score performance. Transformed IS were pooled with HS since aim was to predict intracerebral blood on CT-scan. ! 14! The Besson Score (1995) • Grenoble, France • Prospective • Stroke symptoms, with at least unilat. motor weakness in face and/or arm and/or leg • Excluded bilat. motor weakness, anticoagulant treatment • 368 patients for variable derivation, 200 for validation • Reference test CT 8 dec 2015 26 clinical variables were recorded. 305 patients (82.9 %) had IS and 63 patients had HS, 52 of these were cerebral hematomas and 11 were hemorrhagic infarctions. Table 11: Besson score variables and interpretation (17) Variable Scoring Alcohol consumption 1p for everyday alcohol consumption, regardless of amount Plantar response 0p if absent, 1p if extensor ipsilateral to deficit, 2p if extensor contralateral to deficit, 3p if bilateral extensor Headache Within 2 hours before onset and/or after onset – 1p if present, 0p if absent History of hypertension 0p if absent/unknown, 1p if present History of transient neurological deficit 0p if absent/unknown, 1p if present Peripheral arterial disease 1p if history of lower limb claudication or loss of one or more ankle pulses at examination, 0p if absent History of hyperlipidemia 0p if absent/unknown, 1p if present Atrial fibrillation at admission 0p if absent, 1p if present Formula 5: Calculation of the Besson Score (17) • 200 patients in validation,`LHHJT &HMJEL167 IS • 72 IS correctly classified, while no HS were = 2×&aQMJℎJQ&MJTHUV^IDJT + 1.5×&bQFTIFE&ELH^JTHL + 3×&cLFYFMℎL misclassified+ 3×&cDHIJEd&JS&ℎd^LEILTHDJT − 5×&eEFTHDLTI&TLUEJQJWDMFQ&YLSDMDI − 2×&bLED^ℎLEFQ&FEILEDFQ&YDHLFHL − 1.5×&cDHIJEd&JS&ℎd^LEQD^DYLVDF − 2.5×&aIEDFQ&SD]EDQQFIDJT&JT&FYVDHHDJT A score <1 is indicative of IS. In the prospective study all patients with a score below8 decthe threshold2015 had IS. These made up 40 % of the total of 305 patients with IS. Variable Validation 200 patients were included in the validation study. 167 patients (83.5 %) had IS, 31 patients had cerebral hematomas (15.5 % of total cases) and two patients (1 %) had hemorrhagic infarctions. A score below <1 was reported in 72 IS patients, correctly diagnosing 43 % of patients with IS and 36 % of all patients. The threshold did not diagnose any hemorrhages as non-hemorrhagic, resulting in a PPV at 100 % (95 % CI 93-100) for diagnosing IS. ! 15! The Greek Score (2002) • Athens, Greece • Prospective • Acute stroke • Excluded tumors, anticoagulant treatment • 235 patients for variable derivation, 168 for validation • Reference test CT 8 dec 2015 Table 13: Greek score patient’s characteristics and comparison IS vs. HS (18) Characteristic IS (n=192) HS (n=43) P-value Men 97 (50.5 %) 22 (51.2 %) ns Agea 69.2 ± 11.3