• Vol. 53 No. 8, 519–522
  • 29 August 2024

Impact of risk stratification on cardiovascular outcomes in patients with stable chest pain

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Dear Editor,

Chest pain is a common presenting complaint among patients visiting primary care1 and is a frequent reason for referral to the outpatient cardiology clinic. The European Society of Cardiology (ESC) and American College of Cardiology/American Heart Association (ACC/AHA) guidelines advocate estimating pre-test probability (PTP) of obstructive coronary artery disease (CAD) in the evaluation of stable chest pain in order to guide the need for and type of downstream investigations.2,3 The PTP of obstructive CAD depends on the clinical characteristics of the patient and disease prevalence. Since the introduction of the Diamond-Forrester model in 1979,4 contemporary risk scores, such as the CAD consortium score5 (CCS) and the ESC 2019 PTP risk score,2 have been developed.

These risk scores predict the risk of having obstructive CAD and not clinical outcomes like mortality, myocardial infarction and stroke. Subsequent studies have shown that having a low PTP of obstructive CAD confers a good prognosis with low adverse clinical outcomes and in this group of patients, additional cardiac testing such as stress testing and coronary imaging may be safely deferred.2,3,6 This could potentially translate to time and cost savings to the patient and healthcare system.

The majority of these risk scores were designed for Western cohorts, with subsequent clinical outcomes also validated in similar populations. In Singapore, the Predictive Risk scorE for CAD In Southeast Asians with chEst pain (PRECISE) was recently developed as a risk prediction tool for obstructive CAD in Southeast Asians presenting with stable chest pain.7 We aim to report on the incidence of cardiac testing, as well as objective cardiovascular outcomes, across the different strata of PTP of obstructive CAD.

The detailed methodology has previously been described.7 In summary, the PRECISE cohort comprises patients who attended primary care for stable chest pain and were referred to the National Heart Centre Singapore for further assessment between July 2013 and December 2016. Patients with prior CAD, acute coronary syndrome and under the age of 30 years, were excluded. Ethical approval was obtained. All participants provided written informed consent.

Patients were classified according to their PTP of obstructive CAD, using both the PRECISE simple risk and CCS clinical risk scores. These risk scores use variables including age, sex, cardiovascular risk factors (e.g. hypertension, diabetes mellitus, dyslipidaemia and smoking status), type of chest pain and whether the pain radiated to the neck, and have been previously published.5,7 Additional cardiac stress or anatomical testing (decided by the managing cardiologist) was performed on some patients, and these included treadmill electrocardiogram, stress echocardiogram, myocardial perfusion imaging, computed tomography coronary angiogram, and invasive coronary angiography. Outcomes that were studied include mortality and major adverse cardiovascular events (MACE) defined as a composite of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke and revascularisation (percutaneous coronary intervention [PCI] and/or coronary artery bypass graft surgery). All patients were followed-up for 1 year.

Table 1. Incidence of cardiac testing and cardiovascular outcomes at 1 year in the PRECISE population across the strata of PTP of obstruction CAD using both the PRECISE simple risk and CCS clinical risk scores.

A total of 1658 patients were included with 1469 patients (88.6%) undergoing cardiac testing (stress testing or anatomical evaluation). Using the PRECISE risk score, 793 patients (47.8% of the whole cohort) had a PTP of <5%; within this group, the 1-year mortality and MACE rates were 0.0% and 1.4% respectively, and 86.0% had tests performed. A total of 512 patients (30.9% of the whole cohort) had a PTP of 5%–14.99%; in this group, the 1-year mortality and MACE rates were 0.2% and 6.4% respectively, and 88.9% had tests performed. Additionally, 190 patients (11.5% of the whole cohort) had a PTP of 15%–24.99%; in this group, the 1-year mortality and MACE rates were 0.0% and 10.5% respectively, and 94.7% had tests performed. Moreover, 163 patients (9.8% of the whole cohort) had a PTP of ≥25%; in this group, the 1-year mortality and MACE rates were 0.6% and 20.2% respectively, and 82.8% had tests performed. The majority of MACE rates were driven by revascularisation. Table 1 shows the breakdown of the individual outcomes by risk strata. In a previous publication,7 the PRECISE risk score was found to be more accurate with the CCS clinical risk score overclassifying risk in our Singapore cohort. The results from the CCS clinical risk score are shown in Table 1 for reference.

According to the ESC guidelines, while it may be overall safe to defer testing in patients classified to have a PTP <15%,2 further testing may be considered in a patient with a PTP of 5%–15% depending on patient preference, local resources, availability of tests, clinical judgement and appropriate patient information.2 The ACC/AHA guidelines also advocate deferring testing in patients classified to be low risk. In our Singapore cohort, the 1-year MACE rate in those at very low risk (<5%) was low at 1.4% driven predominantly by revascularisation. However, testing was performed in the vast majority (>80%). In those at low risk (5%–14.99%), the 1-year MACE rate was slightly higher at 6.4%, once again driven predominantly by revascularisation, but the vast majority (about 90%) underwent testing. Additional cardiac testing may be over-utilised, especially in the very low-risk group (PTP<5%). The reasons for these tests are unclear but could be due to multiple reasons, such as patient request, physician preference and perceived malpractice risk. The benefits of cardiac testing in the very low-risk population remain unclear, and reduction of such testing may alleviate the burden on the patient and healthcare system. Unnecessary testing may increase the financial burden on patients, create anxiety and lead to unintended consequences with false positive tests. With regard to the healthcare system, the avoidance of unnecessary testing would free up available limited resources to patients who truly require them, alleviating manpower and resource constraints. This very low-risk patient group accounts for a large majority of referrals, and savings may be substantial. Similar findings have been noted. In a Brazilian study, while lower than in the private sector, there was still a significant amount of inappropriate treadmills (about 57%) ordered in the public sector with the majority of patients having low or very low PTP of CAD.8 Another study in the US estimated that about a third of cardiac stress tests were inappropriate, resulting in increased annual costs and harm.9

Some limitations exist. Whether cardiac testing could have potentially improved cardiovascular outcomes by facilitating the initiation of medical therapy is unknown, as medication data were not readily available. In addition, whether testing led to subsequent revascularisation and consequently reduced mortality or myocardial infarction is unclear. Moreover, many studies have not shown improvement of survival with revascularisation (especially PCI) in stable chest pain.10 Also, in the very low-risk group (PTP <5%), the number of revascularisations is low. Finally, selection bias may exist as not all subjects agreed to take part in the study.

In conclusion, while the incidence of adverse cardiovascular outcomes increased with higher PTP risks, absolute numbers remain low. In the very low-risk strata (PTP <5%), incidence of adverse cardiovascular outcomes is low, and efforts could potentially be made towards reduction in unnecessary testing in this group.

Disclosure

Dr Jonathan Yap received speaker’s honorarium from Abbott, Biosensors, Biotronik, Boston Scientific, Edwards, GE healthcare, J&J, Kaneka, Medtronic and Terumo.

Ethics statement

The manuscript was approved by the SingHealth Centralised Institutional Review Board (CIRB2018/2851).

Acknowledgements

The authors would like to express their heartfelt thanks to the doctors and nurses from SingHealth polyclinics (Dr Andrew Ang, Dr Paul Goh, Dr Lee Cia Sin and Nurse Clinician Joanna Tan), SingHealth Polyclinics Department of Research, and support staff from the National Heart Centre Singapore Specialist Outpatient Clinics for their invaluable help in this project.

Correspondence: Dr Zhen Sinead Wang, SingHealth Polyclinics (Outram branch), 3 Second Hospital Avenue, #02-00 Health Promotion Board Building, Singapore 168937. Email: [email protected]


REFERENCES

  1. Frese T, Mahlmeister J, Heitzer M, et al. Chest pain in general practice: Frequency, management, and results of encounter. J Family Med Prim Care 2016;5:61-6.
  2. Knuuti J, Wijns W, Saraste A, et al. 2019 ESC Guidelines for the diagnosis and management of chronic coronary syndromes. Eur Heart J 2020;41:407-77.
  3. Gulati M, Levy PD, Mukherjee D, et al. 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation 2021;144:e368-e454.
  4. Diamond GA, Forrester JS. Analysis of probability as an aid in the clinical diagnosis of coronary-artery disease. N Engl J Med 1979;300:1350-8.
  5. Genders TSS, Steyerberg EW, Hunink MGM, et al. Prediction model to estimate presence of coronary artery disease: retrospective pooled analysis of existing cohorts. BMJ 2012;344:e3485.
  6. Reeh J, Therming CB, Heitmann M, et al. Prediction of obstructive coronary artery disease and prognosis in patients with suspected stable angina. Eur Heart J 2019;40:1426-35.
  7. Wang ZS, Yap J, Koh YLE, et al. Predicting Coronary Artery Disease in Primary Care: Development and Validation of a Diagnostic Risk Score for Major Ethnic Groups in Southeast Asia. J Gen Intern Med 2021;36:1514-24.
  8. Silva AML, Armstrong AC, Silveira FJC, et al. Prevalence and factors associated with inappropriate use of treadmill exercise stress test for coronary artery disease: a cross-sectional study. BMC Cardiovasc Disord 2015;15:54.
  9. Ladapo JA, Blecker S, Douglas PS. Physician decision making and trends in the use of cardiac stress testing in the United States: an analysis of repeated cross-sectional data. Ann Intern Med 2014;161:482-90.
  10. Sedlis SP, Hartigan PM, Teo KK, et al. Effect of PCI on Long-Term Survival in Patients with Stable Ischemic Heart Disease. N Engl J Med 2015;373:1937-46.
Declaration

The author(s) declare there are no affiliations with or involvement in any organisation or entity with any financial interest in the subject matter or materials discussed in this manuscript.