Background NICE guidelines for patients (PTs) with recent onset of chest pain suspected to be of cardiac origin recommend that CT angiography (CTA) should be the first anatomical test for chest PTs with angina, atypical angina, and non-anginal pain with an abnormal ECG. National audit has shown that, in spite of increasing numbers of CTA being performed, the number of invasive coronary angiograms (ICA) not leading to revascularisation is unchanged. We reviewed 712 CTAs performed in a district general hospital (DGH) to assess the clinical usage of CTA by looking at the requesting clinician’s reason for ordering CTA and outcome in terms of yield of coronary artery disease (CAD)
Methods We reviewed the CTAs requested in 2020 in a large DGH with over 15 requesting clinicians. The clinician’s reason for requesting the CTA was determined from the request form. If the request form did not include the character of the chest pain, the clinic letter was reviewed to determine the reason for requesting CTA. CTAs requested for PTs without chest pain were subcategorised (see below). In PTs with chest pain, we recorded the presence of CAD with a >50% stenosis (CAD50) in any vessel and CAD70 defined as > 70% in the left anterior descending artery or dominant circumflex or right coronary artery. Scans were performed on Toshiba Aquilion I scanners and reported by consultant radiologists (HM & BR)
Results From a total of 717 attendings, 5 scans were not completed (heart rate control & venous access). 49% of the group were female (F) with a mean age of 63 years (F) and 61 years (M). Data from the remaining 712 scans shown in table 1. 241 (34%) scans were performed on PTs without chest pain. Of this group, 139 PTs (20% of total) had CTA to screen for possible CAD because of non-chest pain symptoms including arrhythmias, syncope, breathlessness, prior to non-cardiac surgery and if at high risk for CAD. A group of 90 PTs (13% of total) might have previously had ICA if CTA was not available. This group (B) included 31 (4%) PTs scanned prior to cardiothoracic surgery to exclude coronary disease, 46 (6%) had a previous myocardial infarction or revascularisation and 13 (2%) had CTA to exclude CAD as a cause of heart failure. 8 scans (1%) were to complete an ICA.
Discussion Approximately half of CTAs were performed on PTs who might previously have undergone ICA (groups A, AP & B). However, a substantial number (20%) had CTA to screen for possible CAD. These PTs might previously have had other investigations e.g., treadmill testing.Although ACP is not a guideline indicated reason for CTA, it is the single most common reason (27%) for requesting CTA. This may reflect clinicians’ lack of distinction between ACP and AP, but the low rate of CAD70 in the ACP group suggests that a large number may have had non cardiac chest pain. The CAD50 rate in the ACP, AP and AB groups (50% of total cases) was only 10% suggesting that CTA is largely being used to exclude significant CAD in low or intermediate risk groups. The rate of CAD 70 in group A was only 20%. It is likely that figure is artificially low as, while waiting lists for CTA remain longer than for ICA, clinicians will request ICA as the first test if CAD70 felt likely. Better case selection for CTA could free up capacity for PTs with AA and A. Without this or substantial further increases in CTA capacity, the number of ICAs performed not leading to revascularisation is unlikely to change.
Conflict of Interest None
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