title: Intra-arterial vasodilators to prevent radial artery spasm: a systematic review and pooled analysis of clinical studies.
abstract: OBJECTIVE
  The aim of this study is to review the available literature on the efficacy and safety of agents used for prevention of RAS.
  
  
  BACKGROUND
  Different vasodilator agents have been used to prevent radial artery spasm (RAS) in patients undergoing transradial cardiac catheterization.
  
  
  METHODS
  We included studies that evaluated any intra-arterial drug administered in the setting cardiac catheterization that was undertaken through the transradial access site (TRA). We also compared studies for secondary outcomes of major bleeding, procedure time, and procedure failure rate in setting of RAS prevention, patent hemostasis and radial artery occlusion.
  
  
  RESULTS
  22 clinical studies met the inclusion criteria. For placebo, RAS rate was 12% (4 studies, 638 participants), which was similar to 2.5mg of verapamil 12% (3 studies, 768 participants) but greater than 5mg of verapamil (4%, 2 studies, 497 participants). For nicorandil, there was a much higher RAS rate compared to placebo (16%, 3 studies, 447 participants). The lowest rates of RAS was found for nitroglycerin at both 100 μg (4%) and 200 μg (2%) doses, isosorbide mononitrate (4%) and nicardipine (3%). We found no information regarding the procedure failure rates, patent hemostasis, and radial artery occlusion in these studies.
  
  
  CONCLUSIONS
  In this largest and up-to-date review on intra-arterial vasodilators use to reduce RAS, we have found that the verapamil at a dose of 5mg or verapamil in combination with nitroglycerine are the best combinations to reduce RAS.
authors.affiliation: Keele Cardiovascular Research Group, Keele University, Stoke-on-Trent, UK. Electronic address: shingkwok@doctors.org.uk.
authors.forename: Chun Shing
authors.initials: CS
authors.lastname: Kwok
authors.affiliation: St. Helens & Knowsley Teaching Hospital (NHS) Trust, Whiston Hospital, Prescot, UK.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Rashid
authors.affiliation: Manchester Heart Centre, Manchester Royal Infirmary, UK.
authors.forename: Doug
authors.initials: D
authors.lastname: Fraser
authors.affiliation: University Hospital of North Midlands, Stoke-on-Trent, UK.
authors.forename: James
authors.initials: J
authors.lastname: Nolan
authors.affiliation: Keele Cardiovascular Research Group, Keele University, Stoke-on-Trent, UK; Farr Institute, Institute of Population Health, University of Manchester, Manchester, UK.
authors.forename: Mamas
authors.initials: M
authors.lastname: Mamas
mesh_terms: D000328:Adult; D000368:Aged; D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging / Q000628:therapy; D006328:Cardiac Catheterization / Q000009:adverse effects / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007261:Infusions, Intra-Arterial; D008297:Male; D008875:Middle Aged; D017534:Radial Artery / Q000187:drug effects*; D011859:Radiography; D016032:Randomized Controlled Trials as Topic; D013035:Spasm / Q000517:prevention & control*; D016896:Treatment Outcome; D006113:United Kingdom; D014654:Vascular Patency / Q000187:drug effects; D014665:Vasodilator Agents / Q000008:administration & dosage*
chemical_list: D014665:Vasodilator Agents
keywords: Radial artery catheterization; Radial artery spasm; Vasodilator