Real world data after the implementation of coronary computed tomography angiography in Swedish primary care to rule out coronary artery disease, a cross-sectional study based on pre-test probability

Abstract Background In primary care, most patients with of non-acute chest pain will neither receive a heart related diagnosis nor be referred to a cardiologist. Studies indicate a better cardiovascular prognosis in chest pain patients referred to Coronary Computed Tomography Angiography (CCTA) as compared to risk stratification solely based on risk prediction instruments(1). CCTA is recommended since 2019 for low to intermediate cardiovascular (CV) risk patients(2). In the study setting, the primary care has implemented CCTA as first line test for patients with suspected obstructive coronary artery disease (CAD) and a Pre-Test Probability (PTP) of <15% and any CV risk factor, with PTP mandatorily entered in the referral letters. Purpose To study the outcome of CCTA based on referred PTP values categorised into <5%, 5-15% and >15%. We hypothesized that the presence of significant stenosis would be on par with the mean PTP. Methods In this cross-sectional retrospective cohort study, all consecutive clinical referrals for a CCTA from primary health care centres with a catchment area of ~470 000 inhabitants in the country of Sweden between 1 June 2021 and 7 Dec. 2022, with PTP estimates and completed CCTA were included. CCTA findings were stratified as normal, atheromatosis, or significant stenosis (≥50% coronary lumen obstruction). Patient baseline characteristics routinely registered on the day of CCTA was retrieved from a nationwide quality registry, SWEDEHEART(3). Pearsons’s Chi2 and one-way ANOVA was used to test differences in group distributions. Results During the study period, 381 patients with a PTP had obtained CCTA, of which 75% (n=286) had PTP <15%. The mean age was 60 years (standard deviation [SD] 11), 70% were female, 30% were prescribed lipid-lowering medication and 47% anti-hypertensives (Table 1). In total, the mean PTP was 12.4% (SD 8.7) and in 18% a suspected significant stenosis was identified. (Figure 1). Among patients referred with PTP 5-15%, the presence of suspected significant stenosis was 12% and cardiology consultation was less frequently described than for PTP <5 or ≥15% (14% vs 33% vs 44%, p < 0.001). Conclusions This study indicates that PTP is an efficient means to select patients for CCTA in primary care. In total, about 1/5 had a suspected significant stenosis, which often requires further investigations, and about 4/5 could be reassured that symptoms were not due to coronary artery disease. In 31% atheromatosis was identified, potentially facilitating counselling on CV prevention. We conclude that CCTA is a clinically effective option for primary care physicians to rule out CAD in patients with low PTP.Figure 1Table 1