Date of Award

January 2024

Document Type


Degree Name

Medical Doctor (MD)



First Advisor

Kim G. Smolderen

Second Advisor

Carlos Mena-Hurtado


Background: Clinical trials for carotid artery stenosis treatments have focused primarily on mortality, stroke, and myocardial infarction (MI), but less is known about the effects of carotid revascularization on health status. Our three aims were (1) to establish minimal clinically important differences (MCIDs) as thresholds for meaningful patient-reported clinical improvement for those undergoing transfemoral carotid artery stenting (TF- CAS), (2) to study the distribution of changes in health status 30 days after TF-CAS, and (3) to describe the clinical characteristics of patients who improved significantly after treatment.Methods: Using the Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) database, we studied patients undergoing TF-CAS between 2010 and 2014 and completed either the EQ-5D (n = 3930, 27.74% symptomatic) or the SF-36 (n = 3018, 30.45% symptomatic) health status instruments both within 28 days before and at 30 days after the procedure. MCIDs were calculated to be 0.5 standard deviations of the baseline scores for the 3-level index value and visual analogue scale (VAS) sub-scales of the EQ-5D and the physical and mental component summary (MCS and PCS) sub-scales of the SF-36. Patients’ health status changes were then categorized as improved, deteriorated, or unchanged by comparing them to the MCID. This analysis was performed for both complete cohorts as well as symptomatic and asymptomatic sub-cohorts. Results: The MCIDs for the EQ-5D-3L index value, VAS, SF-36 PCS, and SF-36 MCS were 0.09, 11.02, 5.39, and 4.73, respectively. The rates of improvement across the four sub-scales were 21.14-26.11%. The difference in improvement rate was not statistically significant (standard difference < 0.20) in any of the four sub-scales after stratifying the patients by symptom status. Conclusion: We calculated thresholds for meaningful health status changes in patients undergoing TF-CAS using generic health status instruments and used these thresholds to determine that only approximately 21-26% of patients experienced significant improvement. We then provided descriptive profiles of two groups: those who experienced significant improvement and those who did not. This study is the first to establish MCIDs for clinical improvement using distribution-based methods, which can be used as a reference for future benchmarking for clinical trials and prognostic modeling to determine who will benefit the most from TF-CAS.


This thesis is restricted to Yale network users only. It will be made publicly available on 04/30/2025