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Part II of Evidence Table

Total Asymptomatic Population
Outcomes
30-day Stroke/DeathThreats to
NOther ComplicationsInternal Validity
Study Reference(% Total)Characteristics(Asymptomatic)External ValidityQuality Rating
Bratzler 1996 47 347Not reportedOverall = 3.7%Data collected from medical record and claims databaseGood
(43%)High volume hospital (>100 cases/year) = 3.5%Reviewer blinding not discussed
Low volume hospital = 5.2%No comprehensive evaluation, outcomes determined by coding or documentation in chart
3% HTNGeneralizability low, select population
2% wound hematoma
2% pneumonia
Cebul 1998 48 167Not reported2.4%No assessment of patients, outcomes determined from readmission data; study did not include outpatient visitsFair
(25%)Hospital-specific stroke/death rates inversely related to the number of procedures, ranging from 7.7% lowest quartile to 2.5% highest quartilePredominantly white population
Asymptomatic patients at higher-volume hospitals (greater than median) had no strokes or death at 30 days compared to 4.9% and 4.6% in lower volume hospitals. Outcomes did not differ significantly by surgeon volume.
Undergoing surgery in a higher volume hospital was associated with a 71% reduction in risk of stroke or death at 30 days, after adjusting for patient characteristics (OR=0.29 (0.12–0.69)).
Halm 2003 7 1413Not reportedAsymptomatic with no co-morbidities = 1.28%Complication rates (especially CVA) are underestimated by administrative database.Good
Rockman 2005 55 (65%)Low comorbidity (1 cardiac risk factor) = 2.21%No assessment of patients by neurologist
Halm 2005 53 Moderate (2) = 2.77%All hospitals in 1 region, may not be generalizable.
Press 2006 54 High (ESRD, severe disability or over 2 risk factors) = 5.56%
Mean complication rate across groups = 2.6%
Halm 2007 49 72%Not reportedAsymptomatic without high comorbidity = 2.69%Large number of cases excluded due to missing data.Fair
Asymptomatic with high comorbidity = 7.13%Complication rates (especially CVA) are underestimated by administrative database.
No assessment of patients by neurologist
All hospitals in 1 region, may not be generalizable.
VA - NSQIP 3,231not reported30-day death, CVA, MIReviewer not blinded to treatment, hospital courseGood
Samsa 2002 46 Overall = 2.4%Loss to follow-up not discussed, although likely very little
1994-95 = 2.7%No comprehensive exam by neurologist for outcome assessment
1996-97 = 2.2%No discussion of hospital selection
Other complications not listed
Generalizability low select population (white males)
Horner 2002 45 285220% ≥ 75 yrsStroke or death:Little selection within VA (VA patients are a selected subgroups of US population)Good
(44%)92% White1.6% white
0% Female2.1% black
28% DM2.2% Hispanic
10% COPDStroke, MI or death
2% CHF2.3% white
% CHD NR2.1% black
% HTN NR3.2% Hispanic
% Smoke NR
% Stenosis NR
Karp 1998 50 972Not reportedMortality=0.8%No comprehensive exam by neurologist for outcome assessmentFair
(51%)Mod/Severe Stroke =1.0%No discussion of hospital selection
MI = 0.8%Generalizability low (all males, mostly white)
Combined (above) = 2.6%
All Stroke = 2.4%
Symptomatic patients:
Mortality = 1.7%
Mod/Severe Stroke = 2.7%
MI = 1.4%
Combined (above) = 5.8%
All stroke = 4.7%
Found statistically significant increase in morbidity, mortality and less severe complications at hospitals performing ≤10 CEAs.
Kresowik 2000 52 671Not reportedOverall = 3.4%Unclear when reports of outcomes were given to hospitals & surgeons.Good
(20% '94; 40% '95–96)1994 = 3.8%No comprehensive evaluation, depended on medical records for outcomes.
1995-96 = 3.3%Relied on claims database for readmissions for stoke, death occurring after discharge.
Generalizability
Kresowik 200151 3120Not reportedCombined events 3.7%Missed nonfatal neurologic events occurring after discharge that did not result in another hospitalization.Good
(39%)Mortality 1.1%
The combined event rate by state for asymptomatic patients ranged from 2.3% to 6.7%. Mortality ranged from 0.5% to 2.5%. Only 2 states significantly different from the mean.
Kresowik 200444 4093Not reportedCombined events 3.8%Missed nonfatal neurologic events occurring after discharge that did not result in another hospitalization.Good
The combined event rate by state for asymptomatic patients ranged from 1.4% to 6.0%. Only 3 states significantly different from the mean.

Percentages have been rounded.

1

Past or present smoker;

NR = Not Reported, CEA = carotid endarterectomy DM = diabetes mellitus, COPD = chronic obstructive pulmonary disease, CHF = congestive heart failure, CHD = coronary heart disease, HTN = hypertension, CVA = stroke, MI = myocardial infarction, HMO = health maintenance organization, VA = Veterans affairs, NSQIP = National VA Surgical Quality Improvement Program, CVA = cerebral vascular accident, CABG = coronary artery bypass graft, ESRD = end stage renal disease, OR = odds ratio, MI = myocardial infarction, MEDPAR = Medicare Provider Analysis and Review

From: Appendix 4. Evidence Table on Complications Rates for Carotid Endarterectomy

Cover of Screening For Asymptomatic Carotid Artery Stenosis
Screening For Asymptomatic Carotid Artery Stenosis [Internet].
Evidence Syntheses, No. 50.
Wolff T, Guirguis-Blake J, Miller T, et al.

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