Screening For Carotid Artery Stenosis: An Update of the Evidence. Appendix Table 4

Appendix Table 4. Complication Rates of Carotid Endarterectomy^a

Study Reference	Design	Setting	Source Population	Study Period	Population Selection	Total Population
Study Reference	Design	Setting	Source Population	Study Period	Population Selection	N	Characteristics
Bratzler, 1996⁴⁷	Retrospective, observational study using Medicare claims database and medical records	8 hospitals in Oklahoma (OK)	OK Medicare beneficiaries	1993-1994	All CEA cases from the OK Medicare claims data; hospital selection not specified; all surgeons performing CEA in the 8 study hospitals	813 CEAs (774 patients)	Median-73 yrs % White NR % Female NR 26% DM 20% COPD 10% CHF 67% CHD 71% HTN 26% Smoke 98% had stenosis > 60%
Cebul, 1998⁴⁸	Retrospective, cohort study using Medicare provider analysis and review files	115 hospitals/478 surgeons in Ohio (OH)		7/93-6/94	Random sample of 700 of 4,120 non-HMO Medicare beneficiaries in OH (18 patients had no medical record; 4 had stroke; 3 had bilateral carotid procedures during same hospitalization); hospitals performing CEA in OH	678 patients	Mean-73.1 yrs 94% White 46% Female 26% DMB 16% COPD 9% CHF % CHD NR 71% HTN 31%^b Smoke % stenosis NR
Halm, 2003⁷ Rockman, 2005⁵⁵ Halm, 2005⁵³ Press, 2006⁵⁴	Cross-sectional study based on medical record review of in- and outpatient records	4 university hospitals, 2 community hospitals served by 67 surgeons	-	1/97-12/98	Reviewed 2,365 of 2,390 CEAs based on hospitals' databases. Cases excluded if re-operation, surgery combined with other major procedure, no CEA performed or missing data. Each hospital contributed 130-583 cases.	2124	Mean-72 yrs 87% White 43% Female 29% DM 9% COPD 8% CHF % CHD NR 73% HTN % Smoke NR 96% had >50% stenosis
Halm 2007⁴⁹	Retrospective, observational study using New York State Medicare claims database and medical records		-	1/98-6/99	Reviewed 10, 817 eligible cases (94.8%). Excluded reoperations, CEA combined with CABG, or no CEA performed. 551 cases excluded because of missing data.	9588	Mean-74.6 yrs 93% White 56% Male 30% DM 19% COPD 10% CHF 62% CHD
VA-NSQIP Samsa, 2002⁴⁶	Secondary analysis of VA NSQIP data	132 VA medical centers	Patients undergoing surgery at a VA medical center	1994-1995 1996-1997	94% of those available for assessment included in database, most excluded because of multiple index operations; 5 of the 123 VAs assessed <80% of eligible cases. All VA hospitals performing major surgery; all surgeons performing surgery at VA hospitals.	7,842	Mean-68 yrs 91% White 2% Female 17% DM 17% COPD 2% CHF % CHD NR % HTN NR % Smoke NR % Stenosis NR
Horner, 2002⁴⁵	Secondary analysis of data in VA NSQIP examining differences in CEA outcomes by ethnic group	132 VA Medical Centers	Patients having CEA	10/94-9/97	Limited to men having CEA	6551	20% >75 yrs 91% White 0% Female 29% DM 12% COPD 2% CHF % CHD NR % HTN NR % Smoke NR % Stenosis NR
Karp, 1998⁵⁰	Retrospective, cross-sectional study	Medicare beneficiaries who underwent CEA in Georgia		1993	Excluded 35 cases due to missing data.	1945	Mean-72.3 yrs 91% White 47% Female 22% DM 24% COPD 8% CHF % CHD NR % HTN NR % Smoke NR 69% >75%
Kresowik, 2000⁵²	Retrospective, observational study using Medicare database and medical records	30 hospitals in Iowa	Iowa Medicare beneficiaries	1994 & 6/95 to 5/96	All CEA cases from the Iowa Medicare claims database (Part A & B); all hospitals in Iowa performing CEA on Medicare patients; all surgeons in Iowa performing CEA on Medicare patients	2063	Median-74 yrs % White NR 40% Female % DM NR % COPD NR % CHF NR % CHD NR % HTN NR % Smoke NR % Stenosis NR
Kresowik, 2001⁵¹	Retrospective, observational study using Medicare database and medical records	10 states	Medicare beneficiaries	6/95-5/96	Random sample of 10,561 from 28,083 procedures identified from the MEDPAR Part A claims.	10,030 patients	Mean-73.6 yrs % White NR 43% Female % DM NR % COPD NR % CHF NR % CHD NR % HTN NR % Smoke NR % Stenosis NR
Kresowik, 2004⁴⁴	Retrospective, observational study using Medicare database and medical records	10 states	Medicare beneficiaries	6/98-5/99	Random sample of procedures identified from the MEDPAR Part A claims.	9,945 patients	Mean-NR % White NR 43% Female % DM NR % COPD NR % CHF NR % CHD NR % HTN NR % Smoke NR % Stenosis NR

Appendix Table 4, Continued

Study Reference	Total Asymptomatic Population		30-day Stroke/Death Other Complications (Asymptomatic)	Threats to Internal & External Validity	Quality Rating
Study Reference	N (% Total)	Characteristics	30-day Stroke/Death Other Complications (Asymptomatic)	Threats to Internal & External Validity	Quality Rating
Bratzler, 1996⁴⁷	347 (43%)	Not reported	Overall=3.7% High volume hospital (>100 cases/year) = 3.5% Low volume hospital=5.2% 3% HTN 2% wound hematoma 2% pneumonia	Data collected from medical record and claims database Reviewer blinding not discussed No comprehensive evaluation, outcomes determined by coding or documentation in chart Generalizability low, select population	Good
Cebul, 1998⁴⁸	167 (25%)	Not reported	2.4% Hospital-specific stroke/death rates inversely related to the number of procedures, ranging from 7.7% lowest quartile to 2.5% highest quartile 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 (o.12-0.69)).	No assessment of patients, outcomes determined from readmission data; study did not include outpatient visits Predominantly white population	Fair
Halm, 2003⁷ Rockman, 2005⁵⁵ Halm, 2005⁵³ Press, 2006⁵⁴	1413 (65%)	Not reported	Asymptomatic with no co-morbidities=1.28% Low comorbidity (1 cardiac risk factor) = 2.21% Moderate (2)=2.77% High (ESRD, severe disability or over 2 risk factors)=5.56% Mean complication rate across groups=2.6%	Complication rates (especially CVA) are underestimated by administrative database. No assessment of patients by neurologist. All hospitals in 1 region, may not be generalizable.	Good
Halm 2007⁴⁹	72%	Not reported	Asymptomatic without high comorbidity=2.69% Asymptomatic with high comorbidity=7.13%	Large number of cases excluded due to missing data. Complication rates (especially CVA) are underestimated by administrative database. No assessment of patients by neurologist. All hospitals in 1 region, may not be generalizable.	Fair
VA-NSQIP Samsa, 2002⁴⁶	3,231	Not reported	30-day death, CVA, MI Overall=2.4% 1994-95=2.7% 1996-97=2.2%	Reviewer not blinded to treatment, hospital course. Loss to follow-up not discussed, although likely very little. No comprehensive exam by neurologist for outcome assessment. No discussion of hospital selection. Other complications not listed. Generalizability low select population (white males).	Good
Horner, 2002⁴⁵	2852 (44%)	20% >75 yrs 92% White 0% Female 28% DM 10% COPD 2% CHF % CHD NR % HTN NR % Smoke NR % Stenosis NR	Stroke or death: 1.6% White 2.1% Black 2.2% Hispanic Stroke, MI or death: 2.3% White 2.1% Black 3.2% Hispanic	Little selection within VA (VA patients are a selected subgroups of US population)	Good
Karp, 1998⁵⁰	972 (51%)	Not reported	Mortality=0.8% Mod/Severe Stroke=1.0% MI=0.8% 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.	No comprehensive exam by neurologist for outcome assessment. No discussion of hospital selection. Generalizability low (all males, mostly white).	Fair
Kresowik, 2000⁵²	671 (20% '94; 40% '95-96)	Not reported	Overall=3.4% 1994=3.8% 1995-96=3.3%	Unclear when reports of outcomes were given to hospitals & surgeons. No comprehensive evaluation, depended on medical records for outcomes. Relied on claims database for readmissions for stoke, death occurring after discharge. Generalizability	Good
Kresowik, 2001⁵¹	3120 (39%)	Not reported	Combined events 3.7% 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.	Missed nonfatal neurologic events occurring after discharge that did not result in another hospitalization.	Good
Kresowik, 2004⁴⁴	4093	Not reported	Combined events 3.8% The combined event rate by state for asymptomatic patients ranged from 1.4% to 6.0%. Only 3 states significantly different from the mean.	Missed nonfatal neurologic events occurring after discharge that did not result in another hospitalization.	Good

^a. Percentages have been rounded.
^b. 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

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Appendix Table 4. Complication Rates of Carotid Endarterectomya

Appendix Table 4, Continued

Appendix Table 4. Complication Rates of Carotid Endarterectomy^a