Winning Abstracts from the 2011 Medical Student Abstract Competition: Atropine Prophylaxis a Risk Factor for Post-Carotid Artery Stenting Hypotension
Author: Richard J. VanDam, Wayne State University School of Medicine, Class of 2011
Introduction: Hemodynamic Depression (HD) is a worrisome complication following Carotid Artery Stenting (CAS). Prophylactic atropine helps mitigate the risk of post-stent bradycardia. We assessed the hypothesis that pre-operative systolic BP and prophylactic atropine use are predictive for post-CAS HD.
Methods: Using a single-center prospective CAS registry, we retrospectively reviewed Electronic Medical Records of 109 patients (mean age 72 ±10 years; 68% men) receiving successful CAS between December, 2008 and October, 2010. Of these, 45 patients received prophylactic atropine intra-operatively prior to CAS deployment. Post-CAS HD was defined as symptomatic or asymptomatic hypotension (SBP < 90 mmHg or drop >40%), bradycardia (HR < 60 bpm or drop > 20%), or intra-operative need for vasopressors or anticholinergics post-CAS as surrogate end-points for hypotension and bradycardia respectively. Statistical significance was determined using Student t-test (mean ± SEM) or ?2 for categorical variables (% incidence) and 95% CI.
Results: Mean SBP decreased from baseline following CAS deployment (156±2 to 125±3, p < 0.001, n=109) with a small increase in mean HR (70+1 to 72±1, p=0.03, n=109). The incidence of post-CAS hypotension (n=24), bradycardia (n=38), and both (n=12) was 22%, 35%, and 11% respectively. Drug intervention with either atropine (n=20), dopamine (n=16), or both (n=6) was required in 42 patients for post-CAS HD. Prophylactic atropine was associated with decreased incidence of post-CAS bradycardia (29% vs. 58%, p < 0.01) but increased incidence of hypotension (49% vs. 22%, p < 0.01), leading to no net benefit in preventing HD (73% vs. 64%, p=0.31). While pre-procedural hypertension (SBP=140 mmHg, n=54 of 109) was not predictive of HD overall (p=0.12), it was a risk factor among atropine-treated patients for post-CAS hypotension (65% vs. 25%, p < 0.01) but not bradycardia (p=0.38). Conclusion: In conclusion, atropine prophylaxis carried an increased risk of post-CAS hypotension. While atropine mitigates the risk of post-CAS bradycardia, the concomitant prophylactic use of vasopressors may be warranted to offset the increased risk of hypotension- particularly in patients presenting with elevated SBP immediately prior to the procedure.
Students: Join ACP for Free
Benefits of Membership for Students: ACP's free Medical Student Membership includes benefits designed especially to meet students' needs.
Join Now: Sign-up today and begin enjoying the benefits of ACP Medical Student Membership.
Find a Residency
Search ACP's Internal Medicine Residency Database for information on all internal medicine residency programs in the U.S. and Canada. (ACP Members only)
ACP Clinical Shorts
Expert Education on Your Schedule
Short videos deliver highly focused answers to challenging clinical situations seen in practice and are a terrific way to earn CME credit on-the-go. See more.
New: Free Modules from ACP Practice Advisor!
Keep your practice moving in the right direction. ACP Practice Advisor is offering four modules that you and your staff can try for free. Get to know the premier online practice management tool at no risk. Explore the modules.