Nikolaus Duschek1, Thomas Waldhoer2, Fahroudin Sekic1, Samarth Ghai1, Jasmin Schiebel1, Juergen Falkensammer1, Wolfgang Huebl3, Afshin Assadian1
1Wilhelminenspital Vienna, Department of Vascular Surgery, Vienna, Austria; 2Department of Epidemiology, Center for Public Health, Medical University of Vienna, Vienna, Austria; 3Wilhelminenspital Vienna, Department of Laboratory Medicine, Vienna, Austria.
OBJECTIVES: Background: Efficacy of carotid surgery (CEA) in asymptomatic patients is subject of intense debate. Biomarkers are required to select those who will most likely benefit from CEA for their asymptomatic carotid stenosis (ICAS) despite advanced age. Aim: In this study we assessed plasma total homocysteine (thcy), a widely acknowledged cardiovascular risk factor, as stratifying biomarker to improve prediction of postoperative survival beyond the age of 75 years.
METHODS: Single centered, non-randomized, open-labeled prospective cohort-study from 2003 -2012. Two hundred fourteen consecutive patients (88 female, 126 male, mean age 71 years) undergoing carotid surgery for their asymptomatic high-grade stenosis of their internal carotid stenosis (ICAS) were observed (mean observation period 8.5 years) for the occurrence of death after CEA as primary endpoint. (Local Ethics Committee nr: 04-067-0604) Statistics: Mann-Whitney-U Test was used for comparison of medians, Cox-Regression for estimating thcy-associated hazard ratios. Classic cardiovascular risk factors were used for computation of prognostic indices (PI). Cumulative survival probability of PI-based quintiles was estimated by Kaplan-Meier curves. The effect of the prognostic model was evaluated by the actual percental distribution of age groups age (< / > 75 years) over PI-based quintiles.
RESULTS: Thcy had a significant effect on postoperative survival. Thcy-based quintiles of prognostic indices showed a better prediction of the patients' 5-year (60 months) survival than age alone. This caused reclassification of 17 patients (20.2%) older than 75 years as fit for surgery, but also indicated a high risk for 19 patients (14.6%) younger than 75 years. In 79.8% of over 75 year old patients, statistically, CEA could not be advised due to significantly reduced survival.
CONCLUSIONS: Homocysteine levels, along with other major CVRF, allow a better risk stratification of elderly patients undergoing CEA for their asymptomatic ICAS than an age cut-off of 75 years.
AUTHOR DISCLOSURES: A. Assadian: Nothing to disclose; N. Duschek: Nothing to disclose; J. Falkensammer: Nothing to disclose; S. Ghai: Nothing to disclose; W. Huebl: Nothing to disclose; J. Schiebel: Nothing to disclose; F. Sekic: Nothing to disclose; T. Waldhoer: Nothing to disclose.
Posted April 2013