Rationale for the Assessment of Metoprolol in the Prevention of Vasovagal Syncope in Aging Subjects Trial (POST5)

详细信息    查看全文

• 作者：Satish R. Raj ; MD ; MSCI^a ; ^b ; ^{satish.raj@ucalgary.ca" class="auth_mail" title="E-mail the corresponding author} ; ^{satishrraj@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; Peter D. Faris ; PhD^c ; Lisa Semeniuk ; PhD^a ; Braden Manns ; MD ; MSc^a ; Andrew D. Krahn ; MD^d ; Carlos A. Morillo ; MD^e ; David G. Benditt ; MD^f ; Robert S. Sheldon ; MD ; PhD^a ; on behalf of the POST5 Investigators
• 刊名：American Heart Journal
• 出版年：2016
• 出版时间：April 2016
• 年：2016
• 卷：174
• 期：Complete
• 页码：89-94
• 全文大小：284 K

文摘

Vasovagal syncope (VVS) is a common problem associated with a poor quality of life, which improves when syncope frequency is reduced. Effective pharmacological therapies for VVS are lacking. Metoprolol is a β-adrenergic receptor antagonist that is ineffective in younger patients, but may benefit older (≥40 years) VVS patients. Given the limited therapeutic options, a placebo-controlled clinical trial of metoprolol for the prevention of VVS in older patients is needed.

Structure of study

The POST5 is a multicenter, international, randomized, placebo-controlled study of metoprolol in the prevention of VVS in patients ≥40 years old. The primary endpoint is the time to first recurrence of syncope. Patients will be randomized 1:1 to receive metoprolol 25 to 100 mg BID or matching placebo, and followed up for 1 year. Secondary end points include syncope frequency, presyncope, quality of life, and cost analysis. Primary analysis will be intention to treat, with a secondary on-treatment analysis.

Power calculations

A sample size of 222, split equally between the groups achieves 85% power to detect a hazard rate of 0.3561 when the event rates are 50% and 30% in the placebo and metoprolol arms. Allowing for 10% dropout, we propose to enroll 248 patients.

Implications

This study will be the first adequately powered trial to determine whether metoprolol is effective in preventing VVS in patients ≥40 years. If effective, metoprolol may become the first line pharmacological therapy for these patients.