Geographic disparities in perioperative and mid-term outcomes after elective infrarenal endovascular aneurysm repair
Bibliographic record
Abstract
Objective This study aimed to assess the impact of geographic location on mid-term postoperative outcomes after EVAR across 4 Canadian tertiary care institutions. We hypothesized that patients from rural or non-local areas may experience worse perioperative outcomes because of loss to follow-up, care transfers, and suboptimal surveillance. These factors could contribute to increased non-index readmissions and higher mortality rates following elective endovascular aneurysm repair (EVAR). Methods Elective infrarenal EVAR patients from four Canadian tertiary care institutions were assessed through a retrospective analysis of the Vascular Quality Initiative (VQI) database, stratified by rural versus urban postal codes. A subgroup analysis was also conducted using a 10-year retrospective dataset from Toronto General Hospital (TGH) and the VQI to evaluate EVAR outcomes based on patient geography. Primary outcomes included differences in loss to follow-up, overall survival, and reintervention-free survival. Secondary outcomes included differences in baseline characteristics, perioperative outcomes, and imaging surveillance. Statistical analyses consisted of t-tests for continuous variables, chi-square tests for categorical variables, and Kaplan-Meier survival analysis with log-rank tests. Results Elective EVAR outcomes from four Canadian hospitals (n=1,342 patients) were analyzed by rural versus urban status. Rural patients demonstrated higher postoperative imaging rates but were more likely to be lost to follow-up. Aggregate data revealed a survival advantage for urban patients at 12 months postoperatively. A subgroup analysis from a single tertiary care institution included 491 patients who underwent elective infrarenal EVAR. Patients were categorized by postal code as local versus non-local (80.9% and 19.1%, respectively) and urban versus rural (94.9% and 5.1%, respectively). The median follow-up duration was 32 months (IQR 51). Local and urban patients had significantly higher rates of follow-up within the first two months (local: 84.6% vs. non-local: 57.4%, p<0.001; urban: 80.2% vs. rural: 64.0%, p=0.050) and more frequent imaging between 6 and 12 months (local: 69.5% vs. non-local: 43.6%, p<0.001; urban: 65.9% vs. rural: 40.0%, p=0.008). However, survival analysis did not demonstrate significant differences in estimated mean postoperative survival between groups (urban: 9.19 years vs. rural: 9.87 years, p=0.162; local: 9.15 years vs. non-local: 9.72 years, p=0.219). Conclusions At the national level, four Canadian VQI centres demonstrated higher rates of loss to follow-up and decreased one-year survival among patients from rural communities. In contrast, a subgroup analysis from our institution revealed that rural and non-local patients received fewer follow-up appointments and underwent less postoperative imaging; however, no significant differences in mortality or reintervention were observed. The influence of geographic distance and rurality status on follow-up and imaging highlights a potential vulnerability to aneurysm-related mortality, warranting further investigation.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".