Trends of Intravenous Thrombolysis and Thrombectomy for Low NIHSS Score (<6) Strokes in the United States: A National Inpatient Sample Study

 There are never stroke patients too good to treat. All patients should get to 100% recovery.

Trends of Intravenous Thrombolysis and Thrombectomy for Low NIHSS Score (<6) Strokes in the United States: A National Inpatient Sample Study

Aaron Brake,

Lane Fry,

Hira Chouhdry,

Sivani Lingam,

Tara Samiee,

Romil Singh,

Koji Ebersole and

Michael G. Abraham

Originally published3 Apr 2024https://doi.org/10.1161/SVIN.123.001262Stroke: Vascular and Interventional Neurology. 2024;0:e001262

Abstract

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Stroke management has evolved significantly with the use of intravenous thrombolysis (IVT) and endovascular thrombectomy (EVT). However, low‐severity strokes, National Institutes of Health Stroke Scale (NIHSS) score <6, were mostly absent in the main trials that established the efficacy of EVT and IVT. As the indications for thrombectomy expand for larger and older strokes, there is still ambiguity surrounding its use in these low‐severity cases. This study aims to analyze the trends in IVT and EVT usage as well as functional outcome, inpatient death, and intracranial hemorrhage (ICH) among low‐severity strokes in the United States following the landmark 2015 EVT trials. 

METHODS

Anonymized data and materials have been made publicly available at the Healthcare Cost and Utilization Project National Inpatient Sample database and the data from 2016 to 2020 which were utilized can be accessed at www.hcup‐us.ahrq.gov/nisoverview.jsp.¹ Our analysis can be made available upon reasonable request. The National Inpatient Sample is the United States’ largest inpatient database, with 7 million annual admissions. Managed by the Healthcare Cost and Utilization Project, it features deidentified hospitalization data based on billing and discharge records. Its discharge weights enable national statistical estimates. We analyzed the NIS database from 2016 to 2020 for patients with stroke with NIHSS score <6 on admission. Functional independence, which entails routine home discharge without assistance, was used as our primary outcome, as this has been shown to correlate with modified Rankin scale score ≤ 2 at 90 days.² We also analyzed the rates of inpatient death and ICH. We used the ICH variable International Classification of Diseases, Tenth Revision (ICD‐10) code as opposed to ICH as a sequela of cerebrovascular disease. All annual proportions were compared using logistic regression models, with 2016 as the reference year. Statistical analyses were performed accounting for the sampling design of the National Inpatient Sample, with appropriate strata, weights, and clusters according to Healthcare Cost and Utilization Project guidelines.¹

RESULTS

Baseline patient characteristics can be viewed in Table S1. Compared with 2016, IVT usage decreased significantly by 2020 (11.32% versus 14.88%; odds ratio [OR], 0.769 [95% CI, 0.676–0.874]; P<0.001), while EVT usage incrementally increased during this time and was significantly higher in 2020 (1.97% versus 1.35%; OR,1.466 [95% CI, 1.012–2.123]; P<0.05). Rates of combined IVT and EVT treatment were 0.37% in 2016 and, while slightly increasing, remained statistically unchanged during the period. There was a significant increase in functional independence in 2017 (49.02% versus 46.42%; OR, 1.110 [95% CI, 1.011–1.219]; P = 0.029), 2018 (48.81% versus 46.42%; OR, 1.101 [95% CI, 1.005–1.204]; P = 0.038), and 2019 (49.37 versus 46.42%; OR, 1.125 [95% CI, 1.030–1.230]; P = 0.009), compared with 2016, and a nearly significantly increase in 2020 (48.54% versus 46.42%; OR, 1.089 [95% CI, 0.996–1.190]; P = 0.06). ICH and inpatient death remained statistically unchanged. Trend lines can be visualized in the Figure and the table of outcomes in Table S2.