Coronary artery disease (CAD) is the leading cause of mortality in Asia-Pacific. Despite robust randomised trials and established guideline recommendations for the management of stable CAD, there are significant variations in practice within the Asia-Pacific region regarding the decision for medical treatment versus revascularisation of stable CAD.1–4 In particular, data concerning potential heterogeneity in real-world management of stable CAD among cardiovascular subspecialities are limited, especially between interventional cardiologists (ICs) and non-ICs.
Given the perception of ICs as a hybrid between a physician and surgeon, it is unclear whether this would translate to differences in management decisions for stable CAD.5 The aim of this study was to compare differences in the management of stable CAD between ICs and non-ICs and to explore possible reasons for any discrepancy.
Methods
This study included a subset of participants (ICs and non-ICs) from an anonymised online electronic cross-sectional survey of cardiovascular practitioners in the Asia-Pacific region.4 Briefly, the survey was disseminated through professional networks and shared within professional groups and associations, as well as social media and messaging applications, to potential participants from August 2022 to January 2023. A waiver for ethics approval was sought and granted by the SingHealth Centralised Institutional Review Board because the target respondents were anonymous and participation in the survey was voluntary.
The survey consisted of three main sections. The first section focused on assessing knowledge of the contents of the COURAGE and ISCHEMIA trials, as well as the 2021 American College of Cardiology/American Heart Association guidelines on coronary revascularisation.1–3 The second section focused on individual attitudes and perceptions towards these trials and guidelines. The third section required responses to hypothetical case scenarios asking participants to choose between revascularisation or optimal medical therapy, with the ideal answer being optimal medical therapy for all case scenarios according to the guidelines.3 Further details on the development, validation and contents of the survey have been published elsewhere.4 In the first two sections of the survey, each question was scored as 0 or 1, with 1 indicating a more favourable response. The final score for each section was calculated by averaging the scores across all questions. Comparisons of test scores, as well as responses to individual case questions, between ICs and non-ICs were made using the Wilcoxon signed-rank test in view of the non-parametric nature of the data. Correlations between knowledge, attitude and practice scores were evaluated using Pearson correlation coefficients in bivariate analysis. Logistic regression was performed to identify significant predictors of choosing revascularisation in case scenarios (defined as choosing revascularisation for >50% of case scenarios).
Results
Overall, 618 cardiologists (233 IC and 385 non-ICs) across 21 Asia-Pacific countries completed the survey. Most participants were male (91.1%), aged >40 years (71.8%), in private or rural practice (62.5%) and from developed countries (79.1%; of whom 71.6% were from Japan). ICs were more likely to be male and work in private/rural practice than non-ICs (Table 1 ).
Comparing test scores of individual sections, the IC group had better knowledge scores (median 0.75 [interquartile range (IQR) 0.75–1.0] versus 0.75 [IQR 0.50–1.0]; p<0.01) but poorer attitude scores (median 0.67 [IQR 0.33–1.0] versus 1.0 [IQR 0.67–1.0]; p<0.01) of trials and guidelines than the non-IC group (Figure 1 ). In the non-IC group, higher knowledge scores were weakly correlated with higher attitude scores (r=0.12; 95% CI [0.04–0.23]; p=0.001) and better practice scores (r=0.19; 95% CI [0.09–0.28]; p<0.001). However, no significant correlation was noted between knowledge and attitude (r=−0.09; 95% CI [−0.22, 0.03]; p=0.13) or knowledge and practice scores (r=−0.05, 95% CI [−0.08, 0.17], p=0.49) in the IC group (Figure 2).
Although guidelines recommend medical therapy for all case scenarios, the majority of ICs and non-ICs chose revascularisation. ICs were more likely than non-ICs to choose revascularisation (79.3% versus 70.7%, respectively; p<0.01) across all case scenarios. Closer analysis of individual case scenarios (Figure 3) suggests that ICs were significantly (p<0.05) more likely than their non-IC counterparts to offer revascularisation in cases of mild reversible stress-induced ischaemia (Case 1b) and when there is isolated ischaemia over the inferior myocardium with right coronary artery (RCA) proximal stenosis (Case 1c). On univariate analysis, the only significant variable affecting the decision for revascularisation was interventional subspeciality, which conferred a twofold likelihood for choosing revascularisation (OR 2.06; 95% CI [1.29–3.36]; p<0.01). Multivariate analysis was not performed because there were no other significant variables (Table 2).
Discussion
Several pertinent subspeciality variations between ICs and non-ICs in the management of stable CAD were observed. Despite better knowledge of trials and guidelines in the IC than non-IC group, there was a higher tendency among ICs to choose revascularisation in the case scenarios, consistent with a prior survey of French cardiologists.6 Better knowledge of trials and guidelines also generally reflected more positive perceptions and a tendency to follow guideline recommendations in the non-IC but not IC group.
We can postulate several possible reasons for this difference. ICs may exhibit more action (favouring action over inaction) bias than their non-IC counterparts.7 ICs, by the nature of their training, may have more experience with revascularisation and are thus more likely to recommend this to patients than medical management, which may be perceived as inaction.7 This disparity may be seen especially in cases where the decision for revascularisation is more ambiguous, such as in patients with mild reversible ischaemia (Case 1b) or inferior territory ischaemia (Case 1c). The medical culture appears to reinforce this cognitive bias towards intervention (the ‘oculostenotic’ reflex), resulting in non-evidence-based treatment decisions.8 Inherent personality differences may also exist. Given the nature of work of interventional cardiology as a hybrid between physician and surgeon, ICs may exhibit a personality more akin to that of surgeon’s, and thus may be more pro-procedural than their non-invasive counterparts.5,9 Nonetheless, these explanations are exploratory and require further validation.
Beyond the above factors, there may be other incentives or barriers to revascularisation based on regional differences. There may be a financial incentive for ICs to recommend revascularisation, with a higher proportion of ICs in private/rural practice likely to offer revascularisation. This is consistent with real-world data from the US, a predominantly private insurance-based system, that suggest doubling payments from angioplasties would lead to an 18% increase in angioplasty volume in the treatment of acute MI.10 Varying access to cath lab resources and local practice guidelines are also factors that can influence the decision for revascularisation. The maldistribution of cath labs in larger, less well-developed countries, along with state- or hospital-dependent policies for revascularisation, which may differ slightly from national or international guidelines, may also affect the decision for and the ability to offer revascularisation.11
To the best of the authors’ knowledge, this is one of the first studies exploring the differences in treatment decisions between ICs and non-ICs. Nonetheless, our survey has several limitations. It is uncertain whether these differing practices would have any significant effect on patient outcomes, and this will be a topic for further study. Due to the anonymous and voluntary nature of the survey, the impact of non-responder and selection bias on the generalisability of our results is difficult to ascertain. Given the cross-sectional nature of the study and limitations in data collection, the results of the present study should be considered hypothesis-generating and would benefit from further validation in future studies. Most participants originated from one country (Japan), and this may limit the generalisability of the results in view of differing practices compared with other parts of the Asia-Pacific. Further work should focus on including more participants from across the Asia-Pacific, with a focus on developing countries, to better understand underlying variations. There is also a need for dedicated cost-effectiveness studies to identify the discrepancy in the cost of revascularisation versus medical therapy in developed and developing countries in the Asia-Pacific.
Our data provide intriguing first insights into the subspeciality variations in the management of stable CAD in the Asia-Pacific region. Despite better knowledge of guidelines, ICs were more likely to offer revascularisation than non-ICs, especially in cases of mild or inferior territory ischaemia. Nonetheless, the findings are exploratory and hypothesis-generating due to the cross-sectional study design. The observed discrepancy between guidelines and practice is concerning, and long-term educational efforts are needed to address this gap; this may include regular journal clubs in postgraduate education.12 The practicality and effectiveness of these efforts will be work for future study.
Clinical Perspective
- Significant heterogeneity exists in the management of stable CAD in the Asia-Pacific, especially with regard to the decision for revascularisation.
- Despite better knowledge of guidelines, ICs were generally more likely to offer revascularisation in cases where guidelines recommend medical therapy than their non-IC counterparts.
- Possible reasons for this difference include different clinical experience, personality biases and financial incentives.
- There is a need for long-term educational efforts to address this gap between guidelines and clinical practice.