Volumes, outcomes, and complications after surgical versus endovascular treatment of aneurysms in the United States (1993-2015): continued evolution versus steady-state after more than 2 decades of practice

J Neurosurg. 2020 Feb 7;134(3):848-861. doi: 10.3171/2019.12.JNS192755.


Objective: Adoption of endovascular treatment (EVT) and other advances in aneurysm care have shifted practice patterns of cerebral aneurysm treatment over the past 2 decades in the US. The objective of this study was to determine whether resulting trends in volumes, outcomes, and complications have matured in general practice or continue to evolve.

Methods: Data were obtained from the National Inpatient Sample from 1993 to 2015. ICD-9 codes were used to estimate annual volumes, outcomes, and complications following treatment of ruptured and unruptured aneurysms. Univariate and multivariate analyses were used to estimate risk ratios for complications and outcomes. Trends in time were assessed utilizing annual percentage change (APC).

Results: The authors found a nearly 5-fold increase in annual admissions with diagnoses of unruptured aneurysms, whereas SAH volume increased less than 50%. Clipping ruptured aneurysms steadily declined (APC -0.86%, p = 0.69 until 1999, then -6.22%, p < 0.001 thereafter), whereas clipping unruptured aneurysms slightly increased (APC 2.02%, p < 0.001). EVT tripled in 2002-2004 and steadily increased thereafter (APC 7.22%, p < 0.001 and 5.85%, p = 0.01 for unruptured and ruptured aneurysms, respectively). Despite a 3-fold increase in both diagnosis and treatment of unruptured aneurysms, the incidence of SAH remained steady at 12 per 100,000 persons per year (APC 0.04%, p = 0.83). In contrast, SAH severity increased over time, as did patient age and comorbidities (all p < 0.001). SAH led to nonroutine discharge more frequently over time after both EVT and clipping (APC 1.24% and 1.10%, respectively), although mortality decreased during the same time (APC -2.48% and -1.44%, respectively). Complications were more frequent after clipping than EVT, but this differential risk diminished during the study period and was less perceptible in ruptured aneurysms. The proportion of patients discharged home after treatment of unruptured aneurysms was significantly lower (p < 0.001) after clipping (69.3%-79.5%) than EVT (88.3%-93.3%); both proportions changed minimally since 1998 (APC -0.39%, p = 0.02, and APC -0.11%, p = 0.14, respectively).

Conclusions: EVT volume markedly increased for ruptured and unruptured aneurysms from 1993 to 2015, whereas clipping decreased for ruptured and slightly increased for unruptured aneurysms. The incidence of SAH remained unchanged despite increased diagnosis and treatment of unruptured aneurysms. In ruptured aneurysms, SAH severity has increased over time, as have age, comorbidities, and nonroutine discharges. In contrast, routine discharge after treatment of unruptured aneurysms remains largely unchanged since 1998 and remains lower with clipping.

Keywords: cerebral aneurysm; endovascular treatment; microsurgical clipping; subarachnoid hemorrhage; vascular disorders.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Aneurysm, Ruptured / epidemiology
  • Aneurysm, Ruptured / surgery
  • Databases, Factual
  • Endovascular Procedures / adverse effects
  • Endovascular Procedures / methods*
  • Female
  • Humans
  • Incidence
  • Intracranial Aneurysm / epidemiology
  • Intracranial Aneurysm / surgery*
  • Male
  • Middle Aged
  • Neurosurgical Procedures / adverse effects
  • Neurosurgical Procedures / methods*
  • Patient Admission / statistics & numerical data
  • Postoperative Complications / epidemiology
  • Subarachnoid Hemorrhage / epidemiology
  • Subarachnoid Hemorrhage / surgery
  • Treatment Outcome
  • United States / epidemiology