Cross-sectional comparison of CCT recommendations in the latest ESC vs. ACC/AHA guidelines

Figure 1 shows the number of CCT recommendations in ESC vs. ACC/AHA guidelines, available in 2024, categorized by COR and LOE. The ESC guidelines included 40 recommendations: 18/40 (45%) COR I, 14/40 (35%) COR IIa, 6/40 (15%) COR IIb, and 2/40 (5%) COR III. Only two (5%) of the recommendations had LOE A, 20/40 (50%) LOE B and 18/40 (45%) LOE C. The latest ACC/AHA guidelines consisted of 54 recommendations: 18/54 (33.3%) COR I, 28/54 (51.9%) COR IIa, 6/54 (11.1%) COR IIb and 2/54 recommendation had COR III (3.7%). Two recommendations were assigned LOE A (2/54, 3.7%), 30/54 (55.6%) were classified as LOE B, and 22/54 (40.7%) as LOE C.

Fig. 1

CCT recommendations in ESC vs. ACC/AHA up to 2024

Overall, the distribution of COR was not statistically different between the guidelines (P = 0.54). The ACC/AHA guidelines had a statistically significant higher proportion of COR IIa recommendations compared with the ESC guidelines (51.9% vs. 35%; P = 0.04). Both guidelines showed a similar proportion of COR I and COR IIb recommendations (33.3% vs. 45%, P = 0.28; and 11.1% vs. 15%, P = 0.76, respectively).

The distribution of the LOE was not statistically different between the ESC and ACC/AHA guidelines (P = 0.86). The proportions of LOE-B and LOE-C recommendations were not statistically different (55.6% vs. 50%, P = 0.54; and 40.7% vs. 45%, P = 0.84, respectively). Both the ESC and ACC/AHA guidelines included a limited number of LOE A recommendations, comprising merely two in each case.

Comparison of CCT recommendations by diagnostic subgroups

Figure 2 shows the number of recommendations issued by the ESC and the ACC/AHA, broken down by diagnostic subgroups.

Fig. 2

CCT recommendations in ESC vs. ACC/AHA by diagnosis groups

Acute coronary syndrome (ACS)

For ACS, the ESC [1] and ACC/AHA guidelines [2] included 2 and 7 recommendations, respectively (Supplemental Table 3). There was a higher proportion of recommendations for CCT in ACS in the ACC/AHA guidelines, which did reach statistical significance (2 of 40, 5% vs. 7 of 54, 13%, P = 0.18). With regards to free text - without formal COR - in the guidelines, the ACC/AHA guidelines refer to several clinical situations in which CCT could be performed in patients with acute chest pain and intermediate to high risk of coronary artery disease. In addition, the use of Fractional Flow Reserve Computed Tomography (FFR-CT) is mentioned in ACC/AHA guidelines, but not in ESC guidelines. In contrast, the ESC guidelines only mention that CCT may be performed in patients with suspected ACS, low/negative high-sensitivity troponins, and normal ECG.

Chronic coronary syndrome (CCS)

Regarding CCS, the ESC [3,4,5] and ACC/AHA guidelines [2, 6, 7] included both 15 recommendations (Supplemental Table 4). The proportion of recommendation in this area was not statistically different (15 of 40, 37.5% vs. 15 of 54, 27.7%, P = 0.37). The recently published ESC guidelines included significantly higher COR I recommendations (8 vs. 2, P = 0.02). In the free text of the recommendations, we found a general consensus between ESC and AHA/ACC. Both societies agree that CCT is not recommended as a routine follow-up test for patients with established coronary artery disease.

Arrhythmias

In the context of arrhythmias, the ESC [8, 9] and ACC/AHA [10,11,12] guidelines included 3 and 5 recommendations, respectively (Supplemental Table 5). The proportion of recommendations in this field was not statistically different (3/40, 7.5% vs. 5/54, 9.3%; P = 0.73). When considering the free text of the guidelines, both the ESC and ACC/AHA agree on the role of CCT as an alternative imaging modality—alongside cardiac magnetic resonance and positron emission tomography-computed tomography—for the evaluation of structural heart disease.

Congenital heart disease

For congenital heart disease, the ACC/AHA guidelines [13] included 6 recommendations with a high proportion of COR I (66.7%), while the ESC guidelines [14] did not state any formal recommendations for the use of CCT (0/40, 0% vs. 6/54, 11.1%; P = 0.04) (Supplemental Table 6). In contrast, CCT is formulated in free text as an alternative diagnostic modality for specific indications such as assessment for coronary artery pathology, and detailed assessment of collaterals. The main areas of interest for the use of CCT following the ACC/AHA recommendations are anomalous coronary arteries, anomalous pulmonary venous connection, and aortic anomalies.

Cardiomyopathy & pericardial disease

Regarding cardiomyopathy and pericardial disease, the ESC [15], [16] and the ACC/AHA [2], [17] included 6 and 4 recommendations, respectively (Supplemental Table 7). The proportion of recommendations for CCT in cardiomyopathy and pericardial disease was not statistically different (15% vs. 7.4%, P = 0.32). In pericardial disease, both societies mention the use of CCT to determine the presence of pericardial thickening. In addition, both societies agree on the use of CCT for the further evaluation of cardiomyopathies or hypertrophic cardiomyopathy as an alternative modality when cardiac magnetic resonance imaging is contraindicated or not available.

Valvular heart disease

Regarding VHD, the ESC [18] and the ACC/AHA [19] guidelines included 1 and 10 recommendations, respectively (Supplemental Table 8). The proportion of recommendations for the use of CCT in VHD was higher in the ACC/AHA group and statistically significant (2.5% vs. 18.5%, P = 0.02). The ESC guidelines did not include any COR I, while the ACC/AHA included 6 COR I. Both ESC and ACC/AHA support the use of CCT in patients with low-flow, low-gradient aortic stenosis to further define severity. In addition, the ACC/AHA include recommendations for the use of CCT in suspected mechanical/bioprosthetic valve thrombosis/stenosis and to rule out leaflet thrombosis.

Cardiovascular prevention and sports cardiology

Regarding cardiovascular prevention, the ESC [20], [21], [22] and the ACC/AHA [23], [24] guidelines included 3 and 5 recommendations, respectively (Supplemental Table 9). The proportion of recommendations was not statistically different (7.5% vs. 9.3%, P = 0.73). Both guidelines agree on the use of CCT to calculate coronary artery calcium (CAC) score in patients at intermediate cardiovascular risk to guide further therapeutic decisions. In sports cardiology, the ESC guidelines [25] included 2 recommendations for the use for CCTA. The ACC/AHA guidelines didn’t state any recommendation (Supplementary Table 10).

Endocarditis and cardio-oncology

In the context of endocarditis, the ESC guidelines [26] included 4 recommendations and the ACC/AHA guidelines [19] one (Supplemental Table 11). The proportion of recommendations was not statistically different between the ESC and ACC/AHA (10% vs. 1.8%, P = 0.16). CCT is recommended in patients with possible native and prosthetic valve endocarditis to detect valvular lesions as well as paravalvular or periprosthetic complications and confirm the diagnosis of infective endocarditis. Regarding cardio-oncology, the ESC guidelines [27] included 3 recommendations with a high proportion of COR I (2/3, 66.6%) (Supplemental Table 12). The ACC/AHA guidelines did not state any recommendation for the use of CCT in this field. Although not statistically significant, these are two of the only areas where ESC had more recommendations than AHA/ACC.

Heart failure

Regarding heart failure, both the ESC [28] and ACC/AHA [29] guidelines included one recommendation each (Supplemental Table 13). The ESC guidelines emphasize the role of CCT in patients with heart failure and a low to intermediate pretest probability of coronary artery disease to rule out coronary artery stenosis. In contrast, the ACC/AHA guidelines mention CCT only as an alternative imaging modality to estimate left ventricular ejection fraction when transthoracic echocardiography is inconclusive.