Neurointerventional Treatment in Acute Stroke. Whom to Treat
Transcription
Neurointerventional Treatment in Acute Stroke. Whom to Treat
Cardiovasc Intervent Radiol (2013) 36:1241–1246 DOI 10.1007/s00270-013-0636-9 CLINICAL INVESTIGATION ARTERIAL INTERVENTIONS Neurointerventional Treatment in Acute Stroke. Whom to Treat? (Endovascular Treatment for Acute Stroke: Utility of THRIVE Score and HIAT Score for Patient Selection) Lars Fjetland • Sumit Roy • Kathinka D. Kurz Tore Solbakken • Jan Petter Larsen • Martin W. Kurz • Received: 10 January 2013 / Accepted: 15 April 2013 / Published online: 11 May 2013 Ó Springer Science+Business Media New York and the Cardiovascular and Interventional Radiological Society of Europe (CIRSE) 2013 Abstract Purpose Intra-arterial therapy (IAT) is used increasingly as a treatment option for acute stroke caused by central large vessel occlusions. Despite high rates of recanalization, the clinical outcome is highly variable. The authors evaluated the Houston IAT (HIAT) and the totaled health risks in vascular events (THRIVE) score, two predicting scores designed to identify patients likely to benefit from IAT. Methods Fifty-two patients treated at the Stavanger University Hospital with IAT from May 2009 to June 2012 were included in this study. We combined the scores in an additional analysis. We also performed an additional analysis according to high age and evaluated the scores in respect of technical efficacy. L. Fjetland (&) S. Roy K. D. Kurz Department of Radiology, Stavanger University Hospital, 4068 Stavanger, Norway e-mail: [email protected] S. Roy e-mail: [email protected] K. D. Kurz e-mail: [email protected] L. Fjetland J. P. Larsen M. W. Kurz The Norwegian Center for Movement Disorders, Stavanger University Hospital, 4068 Stavanger, Norway e-mail: [email protected] M. W. Kurz e-mail: [email protected] T. Solbakken J. P. Larsen M. W. Kurz Department of Neurology, Stavanger University Hospital, 4068 Stavanger, Norway e-mail: [email protected] Results Fifty-two patients were evaluated by the THRIVE score and 51 by the HIAT score. We found a strong correlation between the level of predicted risk and the actual clinical outcome (THRIVE p = 0.002, HIAT p = 0.003). The correlations were limited to patients successfully recanalized and to patients \80 years. By combining the scores additional 14.3 % of the patients could be identified as poor candidates for IAT. Both scores were insufficient to identify patients with a good clinical outcome. Conclusions Both scores showed a strong correlation to poor clinical outcome in patients\80 years. The specificity of the scores could be enhanced by combining them. Both scores were insufficient to identify patients with a good clinical outcome and showed no association to clinical outcome in patients aged C80 years. Keywords Neurointerventions Endovascular treatment Stroke therapy Thrombectomy Thrombolysis Brain/ neurological/nervous system Stroke Introduction Stroke is the fourth leading cause of mortality and the leading cause of functional disability in the adult population. Approximately 85 % of all strokes are considered to be ischemic, due to occlusion of an artery providing the brain tissue oxygen and nutrition [1–4]. The therapeutic effect of intravenous thrombolysis (IVT) during the first hours after the onset is well documented in multiple trials and has established itself as the first-line treatment for ischemic stroke [5]. Yet, the thrombolytic effect of IVT is more evident in peripheral small vessels than in central large vessel occlusions where a reperfusion rate of just 123 1242 30 % is reported [6]. In addition, the narrow time window for IVT implies that only a minority of patients is suitable for this treatment. Thus, a more aggressive intra-arterial therapy (IAT) using intra-arterial thrombolysis and mechanical thrombectomy devices has been introduced as a treatment option in patients with central large vessel occlusions. Adoption of this approach also has expanded the therapeutic window to 8 h after symptom onset, from the 4.5 h available for IVT [7, 8]. Trials studying IAT report reperfusion rates varying from 69.5 to 100 % [9, 10]. However, these excellent reperfusion figures are only partially reflected in the clinical results. In most studies only 40–50 % [9, 11, 12] of the patients who are successfully recanalized exhibit a good clinical outcome [13–15]. The fact that early cerebral reperfusion alone is not synonymous with good clinical outcome is of more than academic significance. IAT requires highly specialized expertise and entails the use of a considerable amount of health care resources. What is even more important, it has the nonnegligible potential to cause harm. As a consequence, the current inability to confidently identify the patients most likely to benefit from IAT represents an important hurdle to progress in the therapy of acute stroke. During the past decade, a number of factors have been identified that probably contribute to the outcome achieved after the treatment of acute stroke. These factors comprise age, severity of the stroke at admission measured by NIHSS, hyperglycemia at admission, comorbidity, site of the culprit lesion, collateral cerebral circulation and interval between ictus, and start of treatment [6, 13, 16–22]. By incorporating the most relevant of the clinical factors based on published data, two methods of stratifying patients have been developed: the totaled health risks in vascular events (THRIVE) score [18] and the Houston intra-arterial therapy (HIAT) score [13]. The primary goal of this study was to determine retrospectively whether these scores, independently or jointly, have the potential to serve as a clinical tool for the triage of patients presenting with acute stroke secondary to occlusion of a relatively large vessel. Another object of this study was to evaluate whether the specificity of the scoring systems can be increased by combining them. A secondary goal was to determine whether the utility of the scores was a function of the age of the patient and the technical efficacy (successful vs. unsuccessful recanalization). Materials and Methods Patients From May 2009 to June 2012, all patients admitted to our hospital within 8 h after symptom onset of an acute stroke 123 L. Fjetland et al.: Neurointerventional Treatment in Acute Stroke were considered for study inclusion. All patients underwent cerebral computed tomography (CT). The initial examination included unenhanced CT, perfusion CT, and CT angiography. Patients with an occlusion of M1 segment of the middle cerebral artery (MCA, M1), internal carotid artery (ICA), or basilar artery (BA) on CT angiography, and with no signs of intracranial hemorrhage or distinct demarcation of an infarction [1/3 of the vessel territory were considered potential candidates for IAT within 8 h after symptom onset. Patients with a central arterial occlusion eligible for IVT who arrived at the hospital within 4.5 h from ischemic symptom onset were pretreated with intravenous recombinant tissue plasminogen activator (rt-PA) (Actilyse, Boehringer Ingelheim, Germany). These patients were transferred with ongoing rtPA infusion to the angiography suite for interventional treatment. Those patients arriving later than 4.5 h after symptom onset were transferred directly to the interventional laboratory. No patients were excluded due to old age, recent surgery, or elevated INR. The patients were included in the study after angiographically confirmed large cerebral vessel occlusion. Revascularization Procedures The endovascular treatment was performed by five experienced vascular interventional radiologists. The patients early in the recruitment period were treated with intraarterial thrombolysis; later, two mechanical thrombectomy devices were added to the therapeutic armamentarium: the Penumbra SystemÒ (Penumbra Inc., Alamenda, CA) and the SolitaireÒ FR Revascularization Device (ev3 Neurovascular, Irvine, CA). The performed procedures were described in detail in a previous publication [10]. Efficacy Evaluation Efficacy of the interventional procedure was assessed by the frequency of recanalization of the target vessel. The angiographic recanalization was assessed according to the thrombolysis in myocardial infarction (TIMI) grades. Before treatment, the patients were required to have angiographic documentation of TIMI 0 or TIMI 1 flow in the target vessel at the site of primary occlusion. Successful revascularization was defined by angiographic demonstration of TIMI 2 or TIMI 3 flow in the target vessel [23, 24]. Because arterial recanalization is an independent predictor for good clinical outcome in stroke patients [25], we evaluated the validity of the scoring systems in respect of technical successful reopening of the occluded vessel. L. Fjetland et al.: Neurointerventional Treatment in Acute Stroke 1243 Clinical Evaluation Statistical Analysis Neurologic deficit was graded on admission, the first day after intervention, and at discharge using National Institutes of Health Stroke Scale (NIHSS) [26]. Functional status was assessed at 3 months and assigned a score on the modified Rankin scale [27]. Good clinical outcome was defined as mRS of 2 or less. All statistical analyses were performed using SPSS Statistics version 20 (IBM Corporation, USA). Baseline variables and variable changes were examined using oneway analysis of variance (ANOVA) and Pearson’s Chi squared test as appropriate. The positive predictive value (PPV) was calculated with 95 % confidence interval (CI). THRIVE and HIAT Scores Results The THRIVE and the HIAT score are elucidated in Table 1. For evaluation, the THRIVE scores were trichotomized into a low THRIVE score group with 0–2 points, a medium THRIVE score group with 3–5 points, and a high THRIVE score group with 6–9 points. A HIAT score of 0 or 1 point was considered ‘‘low-risk’’ and 2 or 3 points was considered ‘‘high-risk’’ [23]. To evaluate whether the specificity of the scoring systems can be enhanced without introducing new parameters, we combined both scores in an additional analysis. For this purpose, the THRIVE score was dichotomized into a ‘‘lowmedium risk’’ group (THRIVE 0–5) and a ‘‘high risk’’ group (THRIVE 6–9). The HIAT score was used without modifications. Because age C80 years is an independent predictor for poor outcome in stroke patients [28], we dichotomized our patients around age 80 years and evaluated the validity of the scoring systems in both age groups separately. A total of 52 patients were included in the study. Two patients were intubated before admission because they were unconscious. Because both underwent an abbreviated neurologic examination, they were assumed to have a NIHSS score[21 for the purpose of calculating THRIVE and HIAT scores. The demographic data of the patients included in the study are listed in Table 2. Because the only baseline variable, age was related to clinical outcome (p = 0.004). Fifty-two patients could be scored with the THRIVE predictive scoring system. The data on THRIVE scores in relation to mRS and mortality are summarized in Table 3. The mean THRIVE score in our cohort was 4.6 (SD 1.9) points. We found a strong correlation between the level of predicted risk by the THRIVE score and the clinical outcome (p = 0.002). The correlation between the score and clinical outcome was limited to the subgroup of patients successfully recanalized (p = 0.001). 51.9 % of all patients were classified at medium risk (THRIVE 3–5); patients categorized in this group exhibited a heterogeneous outcome (37 % good clinical outcome). 16 of the 17 patients categorized as high-risk patients Table 1 Calculation of the predictive scores HIAT THRIVE Points Age (year) Table 2 Demographics of the patients Points Age (year) Patients 52 Mean age (year) 70.32 ± 13.27 B 75 0 B 59 0 Age C 80 year 15 (28.8) [ 75 1 60–79 1 Female 15 (28.8) C 80 2 Male 37 (71.2) Mean NIHSS at admissiona 17.4 ± 5.88 Baseline NIHSS score Baseline NIHSS score B 18 0 [ 18 1 Baseline glucose level B 10 0 Baseline glucose C150 mg/dl at admissionb 6 (10.9) 11–20 2 History of hypertension 35 (67.3) C 21 4 History of diabetes mellitus 7 (13.5) History of atrial fibrillation 20 (38.5) Medical history \ 150 mg/dl 0 Diabetes mellitus 1 History of previous ischemic heart disease 5 (9.6) C 150 mg/dl 1 Atrial fibrillation 1 History of previous brain infarction 6 (11.5) 1 0–9 a Data missing in two patients b Baseline glucose value is missing in one patient Range of possible scores 0–3 Hypertension Range of possible scores HIAT score [13] THRIVE score [18] Values represent numbers of patients (%), ±SD 123 1244 L. Fjetland et al.: Neurointerventional Treatment in Acute Stroke Table 3 Association of the THRIVE predictive scoring system with poor clinical outcome (mRS C 3) and mortality by 90 days All Patients 52 (100 %) mRS C 3 Mortality THRIVE 0–2 (%) 8 (15.38) 2 (25)a 0 (0)b THRIVE 3–5 (%) 27 (51.92) 17 (62.97)a 6 (22.2)b THRIVE 6–9 (%) 17 (32.69) 16 (94.1)a 8 (47)b 1 (14.29)c 0 (0)d Recanalized (TIMI 2, 3) THRIVE 0–2 (%) THRIVE 3–5 (%) 40 (100 %) 7 (17.5) 19 (47.5) 9 (47.37) c 4 (21.05)d THRIVE 6–9 (%) Not recanalized (TIMI 0, 1) 14 (35) 1 (100) 0 (0) (42.85)d THRIVE 0–2 (%) 1 (8.33) THRIVE 3–5 (%) 8 (66.67) 8 (100) 2 (25) THRIVE 6–9 (%) 3 (25) 3 (100) 2 (66.67) Pearson Chi square, p = 0.002 b Pearson Chi square, p = 0.04 Pearson Chi square, p = 0.001 d 6 12 (100 %) a c 13 (92.86)c Pearson Chi square, p = 0.09 (THRIVE 6–9) exhibited a poor clinical result (mRS C 3) and the PPV for a poor outcome was 94.1 % (95 % CI 69.2–99.7). In the patient group \80 years, we found a strong correlation between the THRIVE score and the clinical outcome (p = 0.01). Yet in the patient group C80 years, there was no correlation between the score and the clinical outcome (p = 0.6). Although we found a weak correlation between the THRIVE score and mortality in the entire cohort (p = 0.04), the score did not correlate with mortality in either patients group when dichotomized by age. Due to a missing baseline glucose level in one patient, only 51 patients could be scored with the HIAT predictive scoring system. The data on HIAT scores in relation to mRS and mortality are summarized in Table 4. The mean HIAT score was 1 (SD 0.9). We found a strong correlation between the HIAT score and the clinical outcome (p = 0.003) and mortality (p \ 0.001) at 90 days in the entire cohort. The correlations between the score and both clinical outcome (p = 0.002) and mortality (p \ 0.001) were limited to the subgroup of patients successfully recanalized. A total of 66.7 % of the patients were categorized in the low-risk HIAT group (HIAT 0–1); patients in this group exhibited a heterogeneous clinical outcome (47.1 % good outcome). Sixteen of the 17 patients categorized in the high-risk group (HIAT 2–3) had a poor clinical outcome at 90 days and the PPV for a poor outcome was 94.1 % (95 % CI 69.2–99.7). In the group of patients \80 years, 123 we found a strong correlation between the HIAT score and the clinical outcome (p = 0.008) and mortality at 90 days (p \ 0.001). Yet, in the patients group C80 years, there was no correlation between the score and the clinical outcome (p = 0.6) or mortality (p = 0.05). Taking into consideration both the THRIVE and the HIAT score increased the number of patients identified as ‘‘high risk’’ from 17 to 22. Twelve of the patients were categorized as high risk irrespective of the score used. With one exception, a 92-year-old man with a NIHSS score of 19 at admission, every of the patients in this group had a mRS [ 2, giving a PPV for poor outcome of 95.5 % (95 % CI 75.2–99.8). On the contrary, the PPV for good outcome was only 53 % (95 % CI 35–71), if neither THRIVE nor HIAT score predicted high risk. Thus, only 21 of the 35 (60 %) patients with poor clinical outcome would have been identified even if both scores had been prospectively used (Table 5). Discussion We found a strong correlation between the risk of bad outcome as predicted by the THRIVE and HIAT scores and the actual clinical outcome in patients treated with IAT for acute stroke. For the entire cohort, the PPV for poor outcome was 94.1 % (95 % CI 69.2–99.7) for patients deemed to be at high risk based on the THRIVE or the HIAT score. If both scores were taken into consideration, the PPV increased to 95.5 % (95 % CI 75.2–99.8). By simply combining both scoring systems, we could correctly identify nearly 15 % more patients as being at high risk. Flint et al. [18] developed the THRIVE score based on a cohort of patients taking part in the MERCI [9] and the Multi MERCI trials [29]. We used the same definition of poor outcome (mRS C 3) in our study. They found poor outcomes at 90 days in 35.3, 56.5, and 89.4 % of the patients in the low-, medium-, and high-risk groups respectively. Our corresponding figures were 25, 63, and 94.1 % (p = 0.002). Hallevi et al. [13] defined a poor outcome as mRS C 4. Patients categorized in the HIAT low-risk group exhibited a poor clinical outcome in 56.9 %, patients categorized in the HIAT high-risk group in 97.7 % (p \ 0.001). Although we used a wider definition of poor clinical outcome in our cohort (mRS C 3), our figures are in line, 52.9 and 94.1 % respectively (p = 0.003). Ishkanian et al. [30] reported a correlation (p = 0.03) between the THRIVE score and a poor outcome (mRS C 4) but no correlation (p = 0.07) between the HIAT score and outcome. The association between the two scores and the clinical outcome was in our study limited to patients successfully recanalized. In the group of patients not recanalized, there L. Fjetland et al.: Neurointerventional Treatment in Acute Stroke Table 4 Association of the HIAT predictive scoring system with poor clinical outcome (mRS C 3) and mortality by 90 days All Patients 51 (100 %) mRS C 3 Mortality HIAT 0–1 (%) 34 (66.67) 18 (52.94)a 2 (5.88)b HIAT 2–3 (%) 17 (33.33) 16 (94.11)a 12 (70.58)b Recanalized (TIMI 2, 3) 40 (100 %) HIAT 0–1 (%) 27 (67.5) 11 (40.74)c 2 (7.4)d HIAT 2–3 (%) 13 (32.5) 12 (92.3)c 8 (61.53)d Not recanalized (TIMI 0, 1) 11 (100 %) HIAT 0–1 (%) 7 (63.63) 7 (100) 0 (0) HIAT 2–3 (%) 4 (36.36) 4 (100) 4 (100 %) a b Pearson Chi square, p = 0.003 Pearson Chi square, p \ 0.001 c Pearson Chi square, p = 0.002 d Pearson Chi square, p \ 0.001 Table 5 Association of combined THRIVE and HIAT predictive scoring systems with modified rankin scale (mRS) by 90 days Modified Rankin Scale by 90 days THRIVE score 0–5 and HIAT score 0–1 Patients (%) THRIVE score 6–9 or HIAT score 2–3 Patients (%) Total 0–2 16 (53.3) 1 (4.5) 17 (32.7) 3–6 14 (46.7) 21 (95.5) 35 (67.3) 6 2 (6.7) 12 (54.5) 14 (26.9) Patients (%) Pearson Chi square, p \ 0.001 were no associations between the scores and the clinical outcome. None of the patients not recanalized experienced a good clinical outcome, highlighting the vital importance of an early reperfusion. The association between the two scores and the clinical outcome was limited to patients \80 years in our study. This indicates that both scoring systems have a weakness in predicting the risk of patients aged C80 years correctly. Because this group of patients is a growing challenge in the future and because it is predicted that the number of incident strokes among the elderly (age 75?) will more than double during the next 40 years [31], the scores seem to be insufficient to advice in choosing the right treatment concept among the elderly. 1245 Flint et al. reported mortality rates at 90 days of 5.9, 30.1, and 56.4 % in the low-, medium-, and high-risk groups, respectively. We found no association between the THRIVE score and the mortality rate. Hallevi et al. reported a mortality rate of 15.8 and 43.2 %, in the ‘‘lowrisk’’ and the ‘‘high-risk’’ group respectively. Our corresponding figures were 5.9 and 70.6 %. We found a strong correlation between the HIAT score and mortality (p \ 0.001) at 90 days in the entire cohort. However, in patients C80 years the score did not predict mortality. Neither the THRIVE nor the HIAT scores proved to be very reliable to identify patients with a good clinical outcome. A not inconsiderable number of patients with poor neurological outcome are categorized in the low- or medium-risk groups and the PPV for good clinical outcome was only 53 % (95 % CI 35–71), even if neither THRIVE nor HIAT score predicted high risk. Flint et al. also was facing the same challenge with a large medium-risk group containing 48.4 % of their patients, exhibiting quite a variable outcome. Thus, the scores seem to be insufficient to unambiguously identify patients who, despite being apparently good candidates for endovascular intervention, will profit from a transcatheter approach. The relatively low number of patients treated limits somewhat the validity of the conclusions that can be drawn from our results. Yet, our results are in the line with those reported by Flint et al. [18] and Hallevi et al. [13], which do support our main conclusions. A predicting score could be an important tool in an acute stroke treatment algorithm and it is encouraging to demonstrate that it is possible to predict clinical outcome by combining known clinical risk factors in an algorithm. However, the weakness of the THRIVE and the HIAT scores is their overall lack of capability to identify patients with a good clinical outcome and their lack to identify the risk of patients [80 years correctly. Another weakness is that each scoring system categorizes a not inconsiderable number of patients with poor neurological outcome as patients with low- or medium-risk groups. By combining both scores, the number wrongly classified can be reduced but still 46.7 % of the patients experiencing a poor neurological outcome are not classified in the high-risk group. Both scores are simple to administer and fast to perform; thus, both scores seem to be suitable as treatment decision tools in the hyperacute stroke phase where time is scarce. Yet, the prime strength of the two predicting scores, either used alone or in combination is their high predictive value to identify patients, who, despite being apparently good candidates for IAT, do not benefit from the procedure. Use of both scores in the stratification of patients for therapy has the potential to provide added benefit. 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