title: Enrollment volume effect on risk factor control and outcomes in the SAMMPRIS trial.
abstract: OBJECTIVE
  The role of physician experience and patient volumes on the outcome of surgical or endovascular procedures has been well-studied but there are limited data on how these factors affect the outcome of medical therapy.
  
  
  METHODS
  In the stenting and medical cohorts of the Stenting and Aggressive Medical Management for the Prevention of Recurrent Ischemic Stroke (SAMMPRIS) trial, we compared Kaplan-Meier (K-M) curves for the primary endpoint (any stroke or death within 30 days of enrollment or ischemic stroke in the territory beyond 30 days) using the log-rank test and the percentages of patients achieving target levels for primary and secondary risk factors during the study using Fisher exact test between patients at high-enrolling (≥12 patients) vs low-enrolling (<12 patients) sites.
  
  
  RESULTS
  In the stenting group, the K-M curves for the primary endpoint were similar at high-enrolling sites and low-enrolling sites (p = 0.93) with rates of 13.5% vs 14.7% at 30 days and 19.0% vs 20.6% at 2 years. In the medical group, the K-M curves differed between high-enrolling sites and low-enrolling sites (p = 0.0005) with rates of 1.8% vs 9.8% at 30 days and 7.3% vs 20.9% at 2 years. The percentages of patients who achieved targets for low-density lipoprotein cholesterol and systolic blood pressure at high- vs low-enrolling sites in both treatment groups combined were 64% vs 49% (p = 0.003) and 70% vs 59% (p = 0.026), respectively.
  
  
  CONCLUSIONS
  High-enrolling sites in SAMMPRIS achieved better control of primary risk factors and much lower rates of the primary endpoint than low-enrolling sites in the medical group, suggesting that experience with medical management is an important determinant of patient outcome.
authors.affiliation: From Houston Methodist Hospital (D.C., R.P.K., C.D.M., L.B.K.), Weill Cornell Medical College, TX; Medical University of South Carolina (T.N.T., M.I.C.), Charleston; Emory University Rollins School of Public Health (M.J.L., A.N., B.F.L., J.M.), Atlanta, GA; Washington University School of Medicine (C.P.D.), St Louis, MO; State University of New York (D.F.), Stony Brook; and National Institute of Neurological Disorders and Stroke (S.J.), National Institute of Health, Bethesda, MD. dchiu@tmhs.org.
authors.forename: David
authors.initials: D
authors.lastname: Chiu
authors.affiliation: From Houston Methodist Hospital (D.C., R.P.K., C.D.M., L.B.K.), Weill Cornell Medical College, TX; Medical University of South Carolina (T.N.T., M.I.C.), Charleston; Emory University Rollins School of Public Health (M.J.L., A.N., B.F.L., J.M.), Atlanta, GA; Washington University School of Medicine (C.P.D.), St Louis, MO; State University of New York (D.F.), Stony Brook; and National Institute of Neurological Disorders and Stroke (S.J.), National Institute of Health, Bethesda, MD.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Klucznik
authors.affiliation: From Houston Methodist Hospital (D.C., R.P.K., C.D.M., L.B.K.), Weill Cornell Medical College, TX; Medical University of South Carolina (T.N.T., M.I.C.), Charleston; Emory University Rollins School of Public Health (M.J.L., A.N., B.F.L., J.M.), Atlanta, GA; Washington University School of Medicine (C.P.D.), St Louis, MO; State University of New York (D.F.), Stony Brook; and National Institute of Neurological Disorders and Stroke (S.J.), National Institute of Health, Bethesda, MD.
authors.forename: Tanya N
authors.initials: TN
authors.lastname: Turan
authors.affiliation: From Houston Methodist Hospital (D.C., R.P.K., C.D.M., L.B.K.), Weill Cornell Medical College, TX; Medical University of South Carolina (T.N.T., M.I.C.), Charleston; Emory University Rollins School of Public Health (M.J.L., A.N., B.F.L., J.M.), Atlanta, GA; Washington University School of Medicine (C.P.D.), St Louis, MO; State University of New York (D.F.), Stony Brook; and National Institute of Neurological Disorders and Stroke (S.J.), National Institute of Health, Bethesda, MD.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lynn
authors.affiliation: From Houston Methodist Hospital (D.C., R.P.K., C.D.M., L.B.K.), Weill Cornell Medical College, TX; Medical University of South Carolina (T.N.T., M.I.C.), Charleston; Emory University Rollins School of Public Health (M.J.L., A.N., B.F.L., J.M.), Atlanta, GA; Washington University School of Medicine (C.P.D.), St Louis, MO; State University of New York (D.F.), Stony Brook; and National Institute of Neurological Disorders and Stroke (S.J.), National Institute of Health, Bethesda, MD.
authors.forename: Charles D
authors.initials: CD
authors.lastname: McCane
authors.affiliation: From Houston Methodist Hospital (D.C., R.P.K., C.D.M., L.B.K.), Weill Cornell Medical College, TX; Medical University of South Carolina (T.N.T., M.I.C.), Charleston; Emory University Rollins School of Public Health (M.J.L., A.N., B.F.L., J.M.), Atlanta, GA; Washington University School of Medicine (C.P.D.), St Louis, MO; State University of New York (D.F.), Stony Brook; and National Institute of Neurological Disorders and Stroke (S.J.), National Institute of Health, Bethesda, MD.
authors.forename: Lawrence B
authors.initials: LB
authors.lastname: Katz
authors.affiliation: From Houston Methodist Hospital (D.C., R.P.K., C.D.M., L.B.K.), Weill Cornell Medical College, TX; Medical University of South Carolina (T.N.T., M.I.C.), Charleston; Emory University Rollins School of Public Health (M.J.L., A.N., B.F.L., J.M.), Atlanta, GA; Washington University School of Medicine (C.P.D.), St Louis, MO; State University of New York (D.F.), Stony Brook; and National Institute of Neurological Disorders and Stroke (S.J.), National Institute of Health, Bethesda, MD.
authors.forename: Azhar
authors.initials: A
authors.lastname: Nizam
authors.affiliation: From Houston Methodist Hospital (D.C., R.P.K., C.D.M., L.B.K.), Weill Cornell Medical College, TX; Medical University of South Carolina (T.N.T., M.I.C.), Charleston; Emory University Rollins School of Public Health (M.J.L., A.N., B.F.L., J.M.), Atlanta, GA; Washington University School of Medicine (C.P.D.), St Louis, MO; State University of New York (D.F.), Stony Brook; and National Institute of Neurological Disorders and Stroke (S.J.), National Institute of Health, Bethesda, MD.
authors.forename: Colin P
authors.initials: CP
authors.lastname: Derdeyn
authors.affiliation: From Houston Methodist Hospital (D.C., R.P.K., C.D.M., L.B.K.), Weill Cornell Medical College, TX; Medical University of South Carolina (T.N.T., M.I.C.), Charleston; Emory University Rollins School of Public Health (M.J.L., A.N., B.F.L., J.M.), Atlanta, GA; Washington University School of Medicine (C.P.D.), St Louis, MO; State University of New York (D.F.), Stony Brook; and National Institute of Neurological Disorders and Stroke (S.J.), National Institute of Health, Bethesda, MD.
authors.forename: David
authors.initials: D
authors.lastname: Fiorella
authors.affiliation: From Houston Methodist Hospital (D.C., R.P.K., C.D.M., L.B.K.), Weill Cornell Medical College, TX; Medical University of South Carolina (T.N.T., M.I.C.), Charleston; Emory University Rollins School of Public Health (M.J.L., A.N., B.F.L., J.M.), Atlanta, GA; Washington University School of Medicine (C.P.D.), St Louis, MO; State University of New York (D.F.), Stony Brook; and National Institute of Neurological Disorders and Stroke (S.J.), National Institute of Health, Bethesda, MD.
authors.forename: Bethany F
authors.initials: BF
authors.lastname: Lane
authors.affiliation: From Houston Methodist Hospital (D.C., R.P.K., C.D.M., L.B.K.), Weill Cornell Medical College, TX; Medical University of South Carolina (T.N.T., M.I.C.), Charleston; Emory University Rollins School of Public Health (M.J.L., A.N., B.F.L., J.M.), Atlanta, GA; Washington University School of Medicine (C.P.D.), St Louis, MO; State University of New York (D.F.), Stony Brook; and National Institute of Neurological Disorders and Stroke (S.J.), National Institute of Health, Bethesda, MD.
authors.forename: Jean
authors.initials: J
authors.lastname: Montgomery
authors.affiliation: From Houston Methodist Hospital (D.C., R.P.K., C.D.M., L.B.K.), Weill Cornell Medical College, TX; Medical University of South Carolina (T.N.T., M.I.C.), Charleston; Emory University Rollins School of Public Health (M.J.L., A.N., B.F.L., J.M.), Atlanta, GA; Washington University School of Medicine (C.P.D.), St Louis, MO; State University of New York (D.F.), Stony Brook; and National Institute of Neurological Disorders and Stroke (S.J.), National Institute of Health, Bethesda, MD.
authors.forename: Scott
authors.initials: S
authors.lastname: Janis
authors.affiliation: From Houston Methodist Hospital (D.C., R.P.K., C.D.M., L.B.K.), Weill Cornell Medical College, TX; Medical University of South Carolina (T.N.T., M.I.C.), Charleston; Emory University Rollins School of Public Health (M.J.L., A.N., B.F.L., J.M.), Atlanta, GA; Washington University School of Medicine (C.P.D.), St Louis, MO; State University of New York (D.F.), Stony Brook; and National Institute of Neurological Disorders and Stroke (S.J.), National Institute of Health, Bethesda, MD.
authors.forename: Marc I
authors.initials: MI
authors.lastname: Chimowitz
mesh_terms: D002545:Brain Ischemia / Q000175:diagnosis / Q000453:epidemiology* / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D018579:Patient Selection; D012307:Risk Factors; D015607:Stents; D020521:Stroke / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control*; D016896:Treatment Outcome