Every year, Americans pay over 6.5 million visits to emergency departments due to chest pain, in addition to nearly 4 million outpatient clinic visits. While more often than not, this symptom is not related to heart problems, when serious heart events do occur, they are usually preceded by chest pain.
There is now a new guideline being introduced for the evaluation and diagnosis of chest pain. The joint guideline from the American Heart Association and the American College of Cardiology is a new approach to “evaluate the source and symptoms of chest pain can help clinicians improve patient outcomes and reduce health care costs”. In this article, we will be discussing the new guidelines.
International guideline for the evaluation and diagnosis of patients with acute or stable chest pain
Published in the Journal of the American College of Cardiology and Circulation, the flagship journal of the American Heart Association, the new Guideline for the Evaluation and Diagnosis of Chest Pain covers areas such as:
- Initial evaluation
- Cardiac testing considerations
- Diagnostic testing considerations
- Choosing the right pathway with patient-centric algorithms for acute chest pain
- Evaluation of patients with stable chest pain
- Evidence gap
- Future research
The guideline applies a class system for the strength of recommendation of clinical strategies, interventions, treatments, or diagnostic testing inpatient care:
- Class 1 (Strong) – Benefit >>> Risk – is recommended
- Class 2a (Moderate) – Benefit >> Rick – is reasonable
- Class 2b (Weak) – Benefit > Risk – may be reasonable
- Class 3 No Benefit (Moderate) – Benefit = Risk – is not recommended
- Class 3 Harm (Strong) – Risk > Benefit – potentially harmful
When it comes to imaging choice, the guidance states that the decision should be based on the clinical question of importance, to either:
- ascertain the diagnosis of CAD and define the coronary anatomy
- assess ischemia severity among patients with an expected higher likelihood of ischemia with an abnormal resting EKG or those incapable of performing a maximal exercise
CCTA for diagnosing chest pain
CCTA is one of the modalities recommended for diagnosing chest pain in the new chest pain guidelines. This technique can visualize and assist in the diagnosis of the severity and extent of coronary artery disease (CAD). It can also help to assess atherosclerotic plaque composition and offers the advantage of low radiation dosimetry.
According to trials referred to by the guidance, the long-term costs of CCTA are similar to those of stress testing strategies. There is no significant difference between the cost of CCTA and stress testing at two to three years of follow-up, and this is attributed to the matching of higher invasive angiography rates following CCTA by greater use of downstream stress testing after initial stress testing.
CCTA Indications and Guidelines
As outlined previously, Class 1 is the strongest recommendation available for a medical test. Levels A to C is used to represent the strength of the level of evidence of a clinical strategy, intervention, treatment, or diagnostic test. According to the guideline, Level A would indicate that there is “high-quality evidence from more than one randomized clinical trial (RCT) that CCTA is beneficial, useful, and effective”.
In the evaluation and diagnosis of chest pain, CCTA has been designated as:
Acute Chest Pain
Class 1: Evaluating myocardial ischemia or CCTA for graft stenosis or occlusion
Class 1a: Exclusion of atherosclerotic plaque and obstructive CAD
Class 2a: Diagnosing obstructive CAD
Class 2a: Excluding the presence of atherosclerotic plaque and obstructive CAD
Class 2a: Determining the progression of atherosclerotic plaque and obstructive CAD
Stable Chest Pain
Class 2a: CAC testing can be useful in intermediate-high risk patients with no known CAD and stable chest pain undergoing stress testing
Class 2a: CAC testing is sensible as a first-line test for eliminating calcified plaque and detecting patients with a low probability of obstructive CAD
Intermediate-Risk Patients With Stable Chest Pain
Class 1a: CTA is effective for diagnosing patients with CAD, for guiding treatment decisions and risk stratification
Class 2a: CTA is reasonable after an inconclusive or abnormal exercise EKG or stress imaging study
Class 2b: CCTA or ICA may be sensible after a negative stress test but with high clinical suspicion of CAD
Class 2s: CCTA is reasonable to evaluate bypass graft or stent patency (for stents ‡3 mm)
Class 2a: FFR-CT can be used for the diagnosis of vessel-specific ischemia and to guide for intermediate-risk patients with acute chest pain and no known CAD, with a coronary artery stenosis of 40% to 90% in a proximal or middle coronary artery on CCTA, decision-making regarding the use of coronary revascularization
Class 2a: FFR-CT is sensible for the diagnosis of vessel-specific ischemia and to guide decision-making regarding the use of coronary revascularization for intermediate-risk patients with acute chest pain and coronary artery stenosis of 40% to 90% in a proximal or middle segment on CCTA
Class 2a: FFR-CT can be used for the diagnosis of vessel-specific ischemia and to guide decision-making regarding the use of coronary revascularization, for intermediate-high risk patients with stable chest pain and known coronary stenosis of 40% to 90% in a proximal or middle coronary segment on CCTA
In summary, for acute chest pain evaluation, anatomic testing such as CCTA should be carried out on patients with an intermediate risk of major CAD events. When evaluating stable chest pain, anatomic chest pain evaluation should be carried out on patients with a high or intermediate risk of major CAD events. When evaluating acute chest pain, invasive coronary angiography remains the recommendation for those with acute coronary syndrome or a high risk of major CAD events.
The guideline highlights that calculation of fractional flow reserve with CT (FFR-CT) provides an estimation of lesion-specific ischemia. According to the new advice, while in certain situations imaging protocols for the evaluation of the coronary arteries, aorta, and pulmonary arteries may be useful, the general approach should be to use imaging protocols tailored to the most likely diagnosis, rather than a “triple rule-out” approach.
CMR for diagnosing chest pain
CMR is another modality recommended by the new chest pain guidelines. This type of imaging can provide the accurate assessment of global and regional left and right ventricular function, the detection and localization of myocardial ischemia and infarction, and the determination of myocardial viability. CMR is also recommended for the detection of myocardial edema and microvascular obstruction, helping to differentiate between acute and chronic MI, along with other causes of acute chest pain, such as myocarditis.
CMR perfusion and scar imaging have been associated with a favorable incremental cost-effectiveness ratio of <$50,000 per quality-adjusted life-years saved. Referring to the CE-MARC Trial, the guideline pointed out that the CMR strategy proved to be more cost-effective than stress MPI, owing to the modality’s higher diagnostic accuracy. The guideline named initial exercise EKG followed by selective stress CMR and invasive angiography as the most cost-effective strategy. Additional testing was recommended for this tiered testing approach in the case of abnormal or inconclusive findings.
CMR Indications and Guidelines
CMR received five Class 1 and five Class 2a indications in the new international guideline. In the evaluation and diagnosis of acute and stable chest pain, CMR has been designated as:
Acute Chest Pain
Class 1: Acute chest pain with no known CAD
Class 1: Suspected MINOCA/myopericarditis
Class 1: Acute chest pain with prior CABG
Class 2a: Acute chest pain with known CAD
Class 2a: Acute chest pain with known valve disease
Stable Chest Pain
Class 1: Stable chest pain with obstructive CAD
Class 1: Stable chest pain with no known CAD
Class 2a: Suspected INOCA
Class 2a: Stable chest pain with prior CABG
Class 2a: Stable chest pain and non-obstructive CAD
Cardiac Testing Considerations
The guideline included cardiac testing considerations for women who are pregnant, postpartum, or of childbearing age. It was advised that in general, the use of ionizing radiation during pregnancy or postpartum while breastfeeding should be avoided. The benefits and risks of CCTA should be discussed with the patient. The lowest effective dose of ionizing radiation should be used in all cases for clinically necessary tests, and CMR, being a test with no radiation exposure, should be considered.
The issuing of the new chest pain guidelines from the American Heart Association and American College of Cardiology is significant for the advancement of imaging modalities such as CMR and CCTA. The inclusion of CCTA and CMR in the international Guideline for the Evaluation and Diagnosis of Chest Pain is more evidence that these techniques can help clinicians to improve patient outcomes and reduce healthcare costs.
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