Safety and efficacy of oral ivabradine as a heart rate-reducing agent in patients undergoing CT coronary angiography

Low-dose ultra-high-pitch computed tomography coronary angiography: identifying the optimum combination of iteration strength and radiation dose reduction strategies to achieve true submillisievert scans

PURPOSE

To identify the optimum strength of advanced modeled iterative reconstruction (ADMIRE) to achieve the best subjective and objective image quality when combining three-dose reduction strategies, ultra-high-pitch computed tomography coronary angiography (FLASH CTCA; with single-dose ivabradine to lower heart rate), low tube voltage, and ADMIRE.

METHODS

Sixty consecutive patients underwent FLASH CTCA at 100 kVp in this single-center prospective study. Single-dose ivabradine was administered to patients whose heart rate was above 75 bpm. Images were reconstructed using the three highest strengths of ADMIRE (A3, A4, and A5). Objective and subjective image quality (using a Likert scale) were evaluated in the three datasets.

RESULTS

The signal strength remained unchanged but mean noise significantly reduced across the increasing strengths of ADMIRE [signal: 513.78 ± 101.7 Hounsfield units (HU) at A3, 515.6 ± 100.5 HU at A4, and 519.7 ± 107.9 HU at A5; noise: 23.4 ± 4.5 HU at A3, 20.2 ± 3.6 HU at A4, and 17.2 ± 3.3 HU at A5]. Signal-to-noise and contrast-to-noise ratios were the highest at A5, and A5 offered significantly higher Likert scores in image noise, vessel sharpness, and overall image quality than A3 or A4. Additionally, A5 did not interfere with image interpretation in any patient.

CONCLUSION

Using all three dose reduction strategies during FLASH CTCA along with single-dose ivabradine administration ensures minimal radiation exposure in daily practice. In this study, A5 datasets had the best overall subjective and objective image quality despite their "plastic appearance". In the future, enhanced dose reduction can be obtained by further lowering tube voltages.

Effectiveness of point-of-care oral ivabradine for cardiac computed tomography

BACKGROUND

Coronary CT angiography (CCTA) is increasing seen as a first line investigation in patients with suspected coronary artery disease. Heart-rate control improves the image quality and diagnostic accuracy of CCTA. Typically, beta-blockers are administered to induce sinus bradycardia. Sinus bradycardia may also be induced by ivabradine. We hypothesized that in a real-world population ivabradine would be an effective alternative to metoprolol at heart rate lowering for CCTA.

METHODS

This was a retrospective analysis of consecutive patients who were exposed to an ivabradine-based (IB) versus a metoprolol-only (MO) protocol to achieve a target heart rate </ = 65bpm. Hemodynamic responses to both strategies were compared along with differences in cost and the time expired from medication administration to CCTA.

RESULTS

5955 consecutive patients were included in the analysis: 3211 were imaged during an era of a metoprolol only strategy (MO) and 2744 CCTA following an ivabradine based (IB) strategy. 2676 patients had heart rates >65 and received heart-rate lowering medication: 1958 patients had MO, and 718 received IB protocol. Target heart rate of </ = 65bpm was achieved in 77% of MO and 89% of IB patients (p < 0.01). The time from initial medication administration to CCTA was longer in the IB versus MO patients (77 versus 48 min, p < 0.01).

CONCLUSIONS

Introduction of a novel single dose ivabradine-based protocol to control heart rate for CCTA was more successful in achieving target heart rate than a metoprolol-only strategy. The use of ivabradine however incurred a 1.6-fold increase in the time delay from medication administration and imaging compared to a metoprolol only protocol.

Beyond Heart Failure and Ischemic Heart Disease: A Scoping Review of Novel Uses of Ivabradine in Adults

Ivabradine lowers heart rate by inhibiting the hyperpolarization-activated current in pacemaker cells, and its use for the treatment of heart failure (HF) and ischemic heart disease (IHD) is well described. Ivabradine may be an attractive treatment option for other conditions for which a reduction in heart rate is desirable but less is known about its role in these settings. The primary objective was to perform a scoping review summarizing the literature evaluating novel uses for ivabradine other than HF and IHD in adults. PubMed and EMBASE were searched for articles for all dates through September 2019. Search strategies combined terms generic, commercial/trade, and international names for ivabradine. Manual search of references was also performed to identify additional articles. Studies were included if they were published in English, evaluated the efficacy of ivabradine for indications other than HF or IHD in patients aged 18 years or older, and the primary outcome included clinically relevant end points. Articles were screened first by title and abstract followed by full-text screening of the remaining articles. After removal of duplicates, 1807 records were screened for inclusion and 84 studies were included in this scoping review. Novel uses of ivabradine were reported for various tachyarrhythmias, valvular heart disease, premedication for coronary computed tomography angiography, perioperative risk reduction, sepsis with and without multi-organ dysfunction syndrome, cor pulmonale, reactive airway disease, and erectile dysfunction. This scoping review identified several potential novel uses for ivabradine in adults. This review may help to identify existing gaps where further research is needed to elucidate the role of ivabradine for indications beyond HF and IHD.

Ivabradine: Evidence and current role in cardiovascular diseases and other emerging indications

Increased heart rate (HR) is associated with deleterious effects on several disease conditions. Chronic heart failure (CHF) is one of the cardiovascular diseases with recurrent hospitalization burden and an ongoing drain on health-care expenditure. Despite advancement in medicine, management of CHF remains a challenge to health-care providers. Ivabradine selectively and specifically inhibits the pacemaker I(f) ionic current which reduces the cardiac pacemaker activity. The main effect of ivabradine therapy is the substantial lowering of HR. It does not influence intracardiac conduction, contractility, or ventricular repolarization. As shown in numerous clinical studies, ivabradine improves clinical outcomes and quality of life and reduces the risk of death from heart failure (HF) or other cardiovascular causes. Recently updated HF guidelines recommend ivabradine as a class II indication for reduction of HF hospitalizations. Based on the principle of benefits of reduced HR, the ivabradine in patients with ischemic heart disease, sepsis, and multiple organ dysfunction syndrome has also been studied. It can also be a useful agent for HR reduction in patients with contraindications to use beta-blockers or those who cannot tolerate them. In this review, we provide an overview of efficacy and safety of ivabradine and its combination with currently recommended pharmacological therapy in different conditions.

Heart rate-reducing therapy with add-on ivabradine and bisoprolol before coronary computed tomographic angiography in a fast-track ambulatory setting

Objective

This study was performed to determine whether add-on oral ivabradine in patients treated with beta blockers 1 hour before coronary computed tomographic angiography (CCTA) is effective in lowering the heart rate and thus improving CCTA quality.

Methods

In this single-center cohort study, the data of 294 patients referred for ambulant CCTA were retrospectively screened. Patients with an initial heart rate of ≥75 bpm (n = 112) were pretreated with either a combination of bisoprolol and ivabradine or with bisoprolol alone.

Results

During the scan, there was no difference in heart rate between the two groups Likewise, there was no significant difference in additionally administered intravenous bradycardic agents, the number of motion artifacts, or the radiation dose. Both drug regimens were tolerated well.

Conclusion

Additive oral ivabradine 1 hour before CCTA does not result in a further reduction of the heart rate. Consequently, neither movement artifacts nor radiation dose can be reduced. Therefore, pretreatment with ivabradine does not seem reasonably appropriate in an outpatient clinical setting with short patient contact.

Computed tomography coronary angiography with heart rate control premedication: a best practice implementation project

BACKGROUND

Computed tomography coronary angiography patient preparation with heart rate control premedication is employed in departments across Australia. However, the methods of administration vary widely between institutions and do not always follow best practice.

OBJECTIVES

This aim of the study was to identify and promote best practice in the administration of heart rate premedication in computed tomography coronary angiography at a regional hospital in Australia.

METHODS

The Joanna Briggs Institute have validated audit and feedback tools to assist with best practice implementation projects. This project used these tools, which involve three phases of activity - a pre-implementation audit, reflecting on results and implementing strategies to address non-compliance, and a post-implementation audit to assess the outcomes.

RESULTS

A baseline audit identified non-compliance in the majority of measured audit criteria. Following implementation of an institution-specific guideline and associated worksheet, improved compliance was shown across all audit criteria.

CONCLUSIONS

Following the development and implementation of institution-specific evidence-based resources relating to heart rate control in computed tomography coronary angiography, a high level of compliance consistent with best practice was achieved.

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

OBJECTIVE

To evaluate the efficacy and safety of a heart rate (HR) reduction protocol using intravenous esmolol as bailout for failed oral metoprolol regimens in patients undergoing coronary computed tomography angiography (CCTA) with 64-slice multidetector computed tomography (64-MDCT).

METHODS

Patients who underwent cardiac 64-MDCT in a single institution between 2011 and 2014 were analyzed. Those with HR above 60 beats per minute (bpm) on presentation received oral metoprolol (50-200 mg) at least one hour before CCTA. Intravenous esmolol 1-2 mg/kg was administered as a bolus whenever HR remained over 65 bpm just before imaging. The primary efficacy endpoint was HR <65 bpm during CCTA. The primary safety endpoint was symptomatic hypotension or bradycardia up to hospital discharge.

RESULTS

During the study period CCTA was performed in 947 cases. In 86% of these, oral metoprolol was the only medication required to successfully reduce HR <60 bpm. Esmolol was used in the remaining 130 patients (14%). For esmolol-treated patients mean baseline and acquisition HR were 74±14 bpm and 63±9 bpm, respectively (p<0.001). The target HR of <65 bpm was achieved in 82 of the 130 esmolol-treated patients (63%). Considering the whole population, esmolol use led to a significant increase in the primary efficacy endpoint from 86% to 95% (p<0.001). Esmolol also resulted in a statistically, but not clinically, significant reduction in systolic blood pressure (144±22 to 115±17 mmHg; p<0.001). The combined primary safety endpoint was only observed in two (1.5%) patients.

CONCLUSION

Despite optimal use of oral beta-blockers, 14% of patients needed intravenous esmolol for HR control. The pre-medication combination of oral metoprolol and on-demand administration of intravenous esmolol was safe and effective and enabled 95% of patients to be imaged with HR below 65 bpm.

Efficacy of Ivabradine versus β-Blockers for Heart Rate Reduction during Computed Tomography Coronary Angiography: A Meta-Analysis of Randomized Controlled Trials

Objective: To quantify the efficacy of pretreatment with ivabradine compared to β-blockers before computed tomography coronary angiography (CTCA) via a meta-analysis of clinical randomized controlled trial data. Methods: We conducted a search for randomized controlled trials of pretreatment with ivabradine compared to β-blockers before CTCA in Medline, PubMed, Embase, SCI/SSCI/A&amp;HCI, SAS Publishers, Web of Science, and the Cochrane Central Register. The Jadad quality score of the included studies, and the mean difference (MD) in heart rate reduction, were indicators of efficacy. RevMan 5.2 and Stata 12.0 software were used for the meta-analysis. Results: Eight studies involving a total of 1,324 patients were included in the final analysis. The results showed that ivabradine was significantly more effective at improving the heart rate of patients achieving the target heart rate (<65 bpm) during CTCA (OR 5.02; 95% CI 3.16-7.98, p < 0.00001, I2 = 20%). A comparison of efficacy between ivabradine and β-blockers showed a statistically significant effect of ivabradine on heart rate reduction during CTCA (MD -4.39; 95% CI −4.80 to −3.99, p < 0.00001, I2 = 0%). Ivabradine also led to a significant reduction in heart rate prior to CTCA (MD −5.33; 95% CI −10.26 to −0.39, p = 0.03, I2 = 92%). In terms of the total reduction in heart rate during CTCA, significant differences were noted between the ivabradine group and the β-blocker group (MD 2.64; 95% CI 1.25-4.02, p = 0.0002, I2 = 0%). The mean percentage reduction in heart rate in the ivabradine group was significantly higher than that in the β-blocker group (MD 7.18; 95% CI 5.64-8.72, p < 0.00001, I2 = 43%). Ivabradine had no significant effect on either systolic blood pressure (BP) (MD 11.41; 95% CI 6.43-16.40, p < 0.00001, I2 = 85%) or diastolic BP (MD 1.79; 95% CI -0.00 to 3.58, p = 0.05, I2 = 56%). Conclusion: Compared to β-blockers for heart rate reduction, ivabradine is a potentially attractive alternative for patients undergoing CTCA.

Heart rate control with single administration of a long-acting β-blocker at bedtime before coronary computed tomography angiography

BACKGROUND

Beta-blockers are used to control the heart rate prior to coronary computed tomography (CT) angiography. However, in-hospital administration is time-consuming, and it is hard to decrease the heart rate to <60 beats per minute (bpm) when the initial heart rate is increased. In this study, we examined whether the single administration of long-acting β-blocker at bedtime before angiography is effective for achieving the target heart rate.

METHODS AND RESULTS

A total of 314 consecutive patients with a resting heart rate >60bpm who underwent coronary CT angiography were retrospectively collected. Either bisoprolol or atenolol was orally administered the night before to 166 patients (beta group), and no additional medication was administered to the other 148 patients (control group). When the heart rate was >60bpm on arrival, a β-blocker or verapamil was orally administered at the discretion of the physician. Although the baseline heart rate was not significantly different between the groups, the β-blocker treatment the night before significantly reduced the heart rate compared to control group upon arrival at the hospital and at the time of angiography. The rate of achievement of a heart rate ≤60bpm on arrival at the hospital was significantly higher in the beta group, and even after the additional treatment.

CONCLUSIONS

Bedtime administration of a long-acting β-blocker the night before coronary CT angiography is an effective option to achieve the target heart rate at the time of examination.

Safety and efficacy of intravenous esmolol before prospective electrocardiogram-triggered high-pitch spiral acquisition for computed tomography coronary angiography

BACKGROUND

In order to acquire a high quality image with a low radiation dose, prospective electrocardiogram (ECG)-triggered computed tomography coronary angiography (CTCA) requires a stable heart rate (HR) < 65 beats/min. Esmolol has the advantage of reducing HR. The objective of this article is to assess the value of intravenous esmolol treatment before prospective ECG-triggered high-pitch spiral acquisition for CTCA.

METHODS

From March 2013 to June 2013, 313 patients underwent prospective ECG-triggered CTCA. Two hundred and thirty two of them received esmolol before angiography. We retrospectively analyzed clinical characteristics, esmolol dose, radiation exposure dose, and the change in HR and blood pressure in these 232 patients.

RESULTS

A total of 232 patients with a HR > 65 beats/min before CTCA examination received intravenous esmolol treatment (mean dose of 57.26 ± 15.39 mg). The mean initial HR (HR1), slowest HR (HR2), and the HR 30 min after HR2 (HR3) were 75.06 ± 5.59, 60.75 ± 4.00, and 75.54 ± 5.96 beats/min, respectively (HR1 vs. HR2, P < 0.0001; HR1 vs. HR3, P = 0.377). The mean time from esmolol administration to HR2 was 24.25 ± 4.97 s and the mean effective radiation dose was 2.28 ± 0.02 mSv.

CONCLUSIONS

HR could be rapidly controlled at an optimum level with intravenous esmolol before prospective ECG-triggered high-pitch spiral acquisition for CTCA. Consequently, the patients received a very low radiation dose.