title: Ultra-long acting calcium channel blockers may decrease accuracy of the acetylcholine provocation test.
abstract: BACKGROUND
  When drug-induced coronary spasm provocation tests are performed, a washout period of >48h for calcium channel blockers (CCBs) is uniformly recommended. However, each CCB has a distinct half-life, and little is known about the influence of prior oral administration of CCBs on acetylcholine provocation test to evaluate coronary vasomotor reaction.
  
  
  RESULTS
  We examined 245 consecutive patients with suspected vasospastic angina who had undergone acetylcholine provocation test. Of those patients, 29 patients had been on amlodipine, an ultra-long term acting CCB (group A), 34 on other CCBs (group O), and 182 patients on no CCB (group N). After CCBs had been withheld > 48h, we performed acetylcholine provocation, which resulted in 152 positive, 36 intermediate, and 57 negative reactions. We evaluated coronary artery tone calculated as follows: (luminal diameter after nitrate-baseline luminal diameter)÷(luminal diameter after nitrate)×100 (%). In group A patients, coronary artery tone was lower (A:9.1±6.9% vs. O:11.7±8.3% vs. N:12.1±8.5%, p=0.0011) and the positive rate of acetylcholine provocation test was lower than group O and group N (A:41% vs. O:68% vs. N:64%, p=0.047). Multivariate logistic analysis showed that taking amlodipine until 2days before acetylcholine provocation test was a significant inverse predictor for acetylcholine-provoked coronary spasm (odds ratio 0.327; 95% confidence interval 0.125-0.858, p=0.023).
  
  
  CONCLUSIONS
  Residual vasodilatory effects of ultra-long acting CCB may decrease coronary artery tone and the vasoconstrictive reaction to acetylcholine suggesting that a 2-day pre-test drug holiday may not be long enough.
authors.affiliation: Division of Cardiology, Yokohama City Minato Red Cross Hospital, Yokohama, Japan. Electronic address: kurabayashi.card@yokohama.jrc.or.jp.
authors.forename: Manabu
authors.initials: M
authors.lastname: Kurabayashi
authors.affiliation: Division of Cardiology, Yokohama City Minato Red Cross Hospital, Yokohama, Japan.
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Asano
authors.affiliation: Division of Cardiology, Yokohama City Minato Red Cross Hospital, Yokohama, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Shimura
authors.affiliation: Division of Cardiology, Yokohama City Minato Red Cross Hospital, Yokohama, Japan.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: Division of Cardiology, Yokohama City Minato Red Cross Hospital, Yokohama, Japan.
authors.forename: Hideshi
authors.initials: H
authors.lastname: Aoyagi
authors.affiliation: Division of Cardiology, Yokohama City Minato Red Cross Hospital, Yokohama, Japan.
authors.forename: Yasuteru
authors.initials: Y
authors.lastname: Yamauchi
authors.affiliation: Division of Cardiology, Yokohama City Minato Red Cross Hospital, Yokohama, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Okishige
authors.affiliation: Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ashikaga
authors.affiliation: Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Isobe
mesh_terms: D000109:Acetylcholine / Q000008:administration & dosage*; D000368:Aged; D000788:Angina Pectoris, Variant / Q000175:diagnosis* / Q000188:drug therapy; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000145:classification / Q000493:pharmacokinetics; D017023:Coronary Angiography / Q000379:methods; D003329:Coronary Vasospasm / Q000139:chemically induced / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology; D061827:Dimensional Measurement Accuracy; D005260:Female; D006207:Half-Life; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D014665:Vasodilator Agents / Q000008:administration & dosage; D028761:Withholding Treatment / Q000592:standards*
chemical_list: D002121:Calcium Channel Blockers; D014665:Vasodilator Agents; D000109:Acetylcholine
keywords: Acetylcholine provocation test; Calcium channel blocker; Coronary artery spasm; Coronary artery tone