Factors influencing the safety of outpatient coronary CT angiography: a clinical registry study

Abstract

Objectives: Since the safety of coronary CT angiography (CTA) is of great importance, especially with regard to widening indications and increasing morbidity, the aim of this study was to assess influencing factors.

Methods: Patients undergoing coronary CTA in a third-generation dual-source CT in a radiological centre were included in a clinical registry. Up to 20 mg metoprolol was administered intravenously to attain a heart rate ≤65/min. Glyceryl trinitrate (GTN) was administered in doses of 0.8 mg and 0.4 mg. Blood pressure was measured before the administration and after the CTA.

Results: Out of 5500 consecutive patients (3194 men, 62.3 (54.9-70.0) years), adverse events occurred in 68 patients (1.2%) with mild anaphylactoid reactions (0.4%), vasovagal symptoms (0.3%) and extravasation (0.3%) being most frequent. Anti-allergic drugs were given in 17 patients, atropine in 3 patients and volume in 1 patient. Drug administration resulted in a significant mean arterial pressure decline (96.0 (88.3-106.0) vs 108.7 (99.7-117.3) mmHg; p<0.001). Patients who suffered systolic blood pressure drops >20 mmHg or >40 mmHg were older (66.5 (58.6-73.3) vs 60.5 (53.6-68.3) years; 70.2 (63.3-76.5) vs 62.1 (54.7-69.6) years), more often male (65.1% vs 54.4%; 68.9% vs 57.3%) and had higher Agatston score equivalents (83.0 (2.0-432.0) vs 15.0 (0.0-172.0); 163.0 (16.3-830.8) vs 25.0 (0.0-220.0); all p<0.001). GTN dose reduction lowered the fraction of patients suffering from blood pressure drops >20 mmHg or >40 mmHg from 34.5% to 27.4% and from 6.1% to 3.5% (both p<0.001), respectively. The proportion of coronary segments with impaired image quality did not differ significantly.

Conclusions: Coronary CTA with intravenous beta-blocker administration is a safe procedure in an outpatient setting as adverse events are rare and mostly mild. Reduced GTN doses can further improve safety by lowering the rate of significant blood pressure drops, which occurred especially in elderly men with increased plaque burden.

Trial registration number: NCT03815123.

Keywords: Adverse events; CLINICAL PHARMACOLOGY; Cardiology; Cardiovascular imaging; Computed tomography; Coronary heart disease.

Figure 1

Optimised coronary CTA examination protocol. Common contraindications to metoprolol administration: haemodynamic instability, SBP <90 mmHg, heart rate <50/min, sick sinus syndrome, atrioventricular blockage II°/III°, severe asthma, intake of non-dihydropyridine calcium channel blockers, allergy to beta-blockers. CTA, CT angiography; G, gauge; i.v.: intravenously; SBP, systolic blood pressure; s.l., sublingually.

Figure 2

Age distribution. The majority of patients were between 50 and 70 years old and men were slightly but significantly younger than women (61.2 (53.9–69.3) years vs 63.9 (56.5–71.1) years; p<0.001).

Figure 3

Number of periprocedural events. The rate of all periprocedural events inclusive of transient nausea was low with 104 of 5500 patients (1.9%). Adverse events aside from nausea occurred in only 68 patients (1.2%) and were mostly mild.

Figure 4

Rate of significant blood pressure drops depending on glyceryl trinitrate (GTN) dose. The reduction of the standard GTN dose from 0.8 mg to 0.4 mg resulted in significantly lower proportions of patients suffering a drop of the systolic blood pressure (SBP) >20 mmHg as well as >40 mmHg. *P<0.001.