[Usefulness and safety of propranolol injection into vein for acquisition of coronary multidetector-row computed tomography]

Pilot study of bisoprolol 8mg transdermal patch at bedtime before coronary computed tomography angiography

BACKGROUND

Coronary computed tomography angiography (CCTA) is recommended for first-line evaluation of stable coronary artery disease, and there is a standard protocol to control heart rate (HR) in guidelines. However, time is required to decrease HR to the recommended ≤60 beats per minute (bpm). We investigated whether the bisoprolol 8mg transdermal patch at bedtime on the day before CCTA can achieve a target HR and simplify the CCTA process.

METHODS

We randomly assigned 63 patients with an HR of ≥70 bpm and systolic blood pressure ≥120mmHg to a standard protocol group (n=33) or a group (n=30) that applied a bisoprolol 8mg transdermal patch (Bis) at bedtime on the day before CCTA evaluation. The primary endpoint was a change in HR between enrollment in the study and the time of CCTA evaluation. The secondary endpoints were elapsed time from arrival at the CCTA suite to starting CCTA image acquisition, and the rates of oral metoprolol and intravenous landiolol administration (UMIN00035246).

RESULTS

Baseline characteristics did not significantly differ between two groups. HR was significantly lower upon arrival at the CCTA suite in Bis, than standard protocol group (67.5±7.8 bpm vs. 75.0±10.6 bpm; p=0.00002), and the amount of elapsed time from arrival to the start of CCTA evaluation was also significantly decreased in Bis group (76.9±34.9min vs. 94.8±29.2min; p=0.0356). Rates of oral metoprolol and intravenous landiolol administration did not significantly differ between two groups (63.3% vs. 83.3%, p=0.143 and 36.7% vs. 60.0%, p=0.12, respectively).

CONCLUSIONS

The bisoprolol 8mg transdermal patch lowered HR and decreased the amount of time needed for CCTA, thus streamlining the evaluation process.

[Relationship among RR interval, optimal reconstruction phase, temporal resolution, and image quality of end-systolic reconstruction of coronary CT angiography in patients with high heart rates: in search of the optimal acquisition protocol]

The purpose of this study is to elucidate the relationship among RR interval (RR), the optimal reconstruction phase, and adequate temporal resolution (TR) to obtain coronary CT angiography images of acceptable quality using 64-MDCT (Aquilion 64) of end-systolic reconstruction in 407 patients with high heart rates. Image quality was classified into 3 groups [rank A (excellent): 161, rank B (acceptable): 207, and rank C (unacceptable): 39 patients]. The optimal absolute phase (OAP) significantly correlated with RR [OAP (ms)=119-0.286RR (ms), r=0.832, p<0.0001], and the optimal relative phase (ORP) also significantly correlated with RR [ORP (%)=62-0.023RR (ms), r=0.656, p<0.0001], and the correlation coefficient of OAP was significantly (p<0.0001) higher than that of ORP. The OAP range (±2SD) in which it is highly possible to get a static image was from [119-0.286RR (ms)-46] to [119-0.286RR (ms)+46]. The TR was significantly different among ranks A (97 ± 22 ms), B (111 ± 31 ms) and C (135 ± 34 ms). The TR significantly correlated with RR in ranks A (TR=-16+0.149RR, r=0.767, p<0.0001), B (TR=-15+0.166RR, r=0.646, p<0.0001), and C (TR=52+0.117RR, r=0.425, p=0.0069). Rank C was distinguished from ranks A or B by linear discriminate analysis (TR=-46+0.21RR), and the discriminate rate was 82.6%. In conclusion, both the OAP and adequate TR depend on RR, and the OAP range (±2SD) can be calculated using the formula [119-0.286RR (ms)-46] to [119-0.286RR (ms)+46], and an adequate TR value would be less than (-46+0.21RR).

[Estimation of radiation dose and image quality of coronary 320-row area detector CT angiography by optimal prospective ECG-gated protocols for different heart rate]

The purpose of this study is to estimate radiation dose and image quality of ECG-gated coronary 320-area detector CT (ADCT) angiography which was acquired using the protocols that were considered as optimal methods for different heart rates (HR) in 1031 consecutive patients (M/F=580/451, 65 ± 12 yr) without arrhythmias. We set up 5 protocols for 320-ADCT based on the relationship among heart rates, temporal resolution, gantry rotation speed, optimal reconstruction phase and slow filling phase on 64-multidetector-row computed tomography (MDCT), ie, 1) mid-diastolic (75% of RR) 1 beat scan (MD 1 beat, N=761(73.8%)) for HR ≤ 60, 2) mid-diastolic (75% of RR) 2 beat scan (MD 2 beat, N=135) for 61 ≤ HR ≤ 65, 3) end-systolic and mid-diastolic (37-80% of RR) 2 beat scan (ES-MD 2 beat, N=92) for 66 ≤ HR ≤ 75, 4) end-systolic (R+280-430 ms) 2 beat scan (ES 2 beat, N=21) for 76 ≤ HR ≤ 80, and 5) end-systolic (R+250-400 ms) 3 beat scan (ES 3 beat, N=22) for 81 ≤ HR ≤ 105. Image quality was classified into 3 categories (excellent (3 points), acceptable (2 points), and unacceptable (1 point)). Scanning time, DLP.e and image quality score were 1.4 ± 0.1 s, 220 ± 59 mGy·cm, 3.0 ± 0.2 points in MD 1 beat, 2.2 ± 0.2 s, 434 ± 118 mGy·cm, 2.9 ± 0.3 points in MD 2 beat, 2.1 ± 0.2 s, 729 ± 229 mGy·cm, 2.7 ± 0.5 points in ES-MD 2 beat, 1.9 ± 0.1 s, 432 ± 148 mGy·cm, 2.2 ± 0.6 points in ES 2 beat, and 2.4 ± 0.2 s, 669 ± 152 mGy·cm, 2.3 ± 0.6 points in ES 3 beat respectively. In conclusion, the prospective ECG-gated scan protocol for coronary 320-ADCT angiography in any HR group was considered reasonable and proper for image quality and radiation dose.