Failed heart rate control with oral metoprolol prior to coronary CT angiography: effect of additional intravenous metoprolol on heart rate, image quality and radiation dose

Abstract

The purpose of this study was to evaluate the effect of intravenous (i.v.) metoprolol after a suboptimal heart rate (HR) response to oral metoprolol (75-150 mg) on HR control, image quality (IQ) and radiation dose during coronary CTA using 320-MDCT. Fifty-three consecutive patients who failed to achieve a target HR of < 60 bpm after an oral dose of metoprolol and required supplementary i.v. metoprolol (5-20 mg) prior to coronary CTA were evaluated. Patients with HR < 60 bpm during image acquisition were defined as responders (R) and those with HR ≥ 60 bpm as non-responders (NR). Two observers assessed IQ using a 3-point scale (1-2, diagnostic and 3, non-diagnostic). Effective dose (ED) was estimated using dose-length product and a 0.014 mSV/mGy.cm conversion factor. Baseline characteristics and HR on arrival were similar in the two groups. 58% of patients didn't achieve the target HR after receiving i.v. metoprolol (NR). R had a significantly higher HR reduction after oral (mean HR 63.9 ± 4.5 bpm vs. 69.6 ± 5.6 bpm) (p < 0.005) and i.v. (mean HR 55.4 ± 3.9 bpm vs. 67.4 ± 5.3 bpm) (p < 0.005) doses of metoprolol. Studies from NR showed a significantly higher ED in comparison to R (8.0 ± 2.9 vs. 6.1 ± 2.2 mSv) (p = 0.016) and a significantly higher proportion of non-diagnostic coronary segments (9.2 vs. 2.5%) (p < 0.001). 58% of patients who do not achieve a HR of <60 bpm prior to coronary CTA with oral fail to respond to additional i.v. metoprolol and have studies with higher radiation dose and worse image quality.

Esmolol is noninferior to metoprolol in achieving a target heart rate of 65 beats/min in patients referred to coronary CT angiography: A randomized controlled clinical trial

“…However, it is important to note that the combined use of oral and IV b-blockers is a widely used and effective strategy for HR lowering before coronary CTA. 6,24 In this scenario, esmolol is at least as efficacious as IV metoprolol. The response rate to oral metoprolol was relatively low in our study (162 of 574 [28%]), which might have been higher with the use of a more aggressive administration regime (eg, 100-mg oral metoprolol if HR >65 beats/min).…”

Bailout intravenous esmolol for heart rate control in cardiac computed tomography angiography

“…In a study by Jimenez-Juan et al only 42% of patients who did not achieve HR <60 bpm with oral metoprolol reached target HR with additional intravenous metoprolol. 19 These findings highlight the need for a more effective protocol for HR control. In addition, the rapid action and short half-life of esmolol make it an attractive drug in this setting.…”

SEALONE (Safety and Efficacy of Coronary Computed Tomography Angiography with Low Dose in Patients Visiting Emergency Room) trial: study protocol for a randomized controlled trial

“…Therefore a quick and simple but effective heart rate control protocol that can be readily adopted in chaotic ED is essential. We reviewed previous studies [ 19 - 25 ] and prepared heart rate control protocols based on both oral beta-antagonist and IV esmolol bolus administration at the beginning of the study. If a patient has sufficient physiologic reserve to compensate for the prolonged beta-blocking effect, oral beta-antagonist (with additional IV esmolol bolus if required) is a great option because of its simplicity.…”