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Patient Comprehension Necessary for Informed Consent for Vascular Procedures is Poor and Related to Frailty
Jack Ruske, Gaurav Sharma, Kevin Makie, Katherine He, C K Ozaki, Matthew T Menard, Michael Belkin, Samir K Shah
Brigham and Women's Hospital, Boston, MA

Background. Informed consent is an essential principle of high-quality healthcare. A core component of surgical informed consent is patient comprehension of basic information, such as the diagnosis, and the risks, benefits, and alternatives of the proposed surgery. While studies in other fields have found varying levels of patient comprehension, there is a lack of data in vascular surgery. We sought to study comprehension after informed consent among vascular surgery patients.
Methods. We tested patient comprehension of basic information required for informed consent with a procedure-specific questionnaire in 76 consecutive patients undergoing carotid endarterectomy(CEA), aortic aneurysm repair, hemodialysis access creation, and percutaneous lower extremity procedures. In addition all patients underwent assessment using the decisional conflict scale and the Frail/Nondisabled questionnaire. Decisional conflict refers to patient uncertainty related to factors such as a sense of feeling poorly informed. We classified a patient as “informed” if he or she was able to answer a procedure-specific set of questions correctly. Analyses were performed to determine relationships between being informed and frailty, education level, and decisional conflict score. All analyses were performed using SAS(v9.4, SAS Institute Inc., Cary, NC).
Results. Our study included 76 patients; 74 were analyzed because 2 patients underwent open aortic aneurysm repair and were excluded because of small sample size. Patients had a median age of 71 years and 23.0%, 16.2%, 24.3%, and 36.5% underwent CEA, endovascular aortic aneurysm repair (EVAR), dialysis access creation, and percutaneous lower extremity procedures. Demographic characteristics are summarized in table 1. Patient ability to correctly answer questions about essential information such as risks varied but was generally low(e.g. only 53% of patients undergoing CEA were able to identify stroke as a risk) (Table 2). Only 10(13.5%) patients overall were “informed”(i.e. correctly answered all questions). There was no correlation between being informed and education level(p=0.09) or whether the consent was obtained by the attending surgeon(p=0.14). There was a correlation with frail/disabled status(p=0.03). Mean decisional conflict scale scores was 12.2, suggesting low levels of conflict.
Table 1. Subject and procedure characteristics

Median age [IQR]71 [62, 77]
Female sex (%)29 (38)
Highest education level completed
Less than high-school (%)5 (6.6)
High-school or equivalent (%)23 (30.3)
Some college (%)15 (19.7)
College or post-graduate studies (%)33 (43.4)
Frailty Score2 [1, 3]
Type of procedure
Carotid endarterectomy (%)17 (23.0)
Endovascular aortic aneurysm repair (%)12 (16.2)
Dialysis access (%)18 (24.3)
Percutaneous lower extremity procedure (%)27 (36.5)

*Mean and (standard error of the mean) are presented for normally distributed variables; median and [interquartile range] are presented for non-normally distributed variables
Table 2. Results of procedure-specific questionnaires
Procedure typeVariableValue
Carotid Endarterectomy (CEA, n=17 with 2 symptomatic)Correct indication (%)10 (59)
Able to name stroke as a risk (%)9 (53)
Able to name any alternative to CEA including medical management (%)2 (12)
Mean (range) stated procedural stroke risk8 (0-35)
Mean (range) stated procedural mortality4 (0-20)
Mean (range) stated baseline annual stroke risk without CEA35 (0-100)
Endovascular aneurysm repair (EVAR, n=12)Correct indication (%)8 (67)
Able to name hemorrhagic complications as a risk (%)7 (58)
Able to name open surgery as an alternative (%)6 (50)
Mean (range) stated procedural death risk6.4 (0-30)
Aware that long-term postoperative surveillance required (%)10 (83)
Mean (range) stated risk of reintervention within 4 years18 (0-50)
Mean (range) estimated hospital length of stay in days2.8 (2-3)
Expected to be discharged home (%)12 (100)
Hemodialysis access (n=18, all fistulas)Correct indication (%)16 (89)
Able to name hemorrhagic complications as a risk (%)5 (28)
Able to name an alternative (%)4 (22)
Mean (range) stated procedural mortality10 (0-50)
Mean (range) stated days to maturation per patient103 (7-365)
Percutaneous lower extremity arterial procedure (n=27)Correct indication (%)12 (44)
Able to name any complication as a risk (%)17 (63)
Able to name an alternative (%)8 (30)
Mean (range) stated procedural mortality19 (0-70)
Mean (range) stated 5-year major leg amputation risk without intervention40 (0-100)

Conclusion. There is poor comprehension of basic information about diagnosis and procedural risks, benefits, and alternatives. This is associated with frail/disabled status but not with education level. Despite poor overall comprehension patients feel little decisional conflict, suggesting that they feel well-informed and supported. These findings have potential ethical and clinical implications. Additional work is required to best determine causes of poor comprehension and strategies to mitigate the same.

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