Chronic Coronary Syndrome in Swedish Primary Care

In primary health care patients with chest symptoms are common. In many cases the cause is benign but chronic coronary artery disease (CAD) must often be considered. In the clinical work, evaluation of symptoms and risk factors are fundamental for a plausible working diagnosis and to judge if any further investigation is needed. The probability of CAD for a person of a certain age, sex and character of chest symptoms, scored from 0-3, i.e. pretest probability (PTP) for CAD, is substantially lower now than it was a decade ago in western countries. Consequently, recent European guidelines recommend that further investigation to rule out CAD may be omitted if the risk for CAD is judged to be low (PTP<15 %) and there are no further cardiovascular risk factors. If further investigation is needed in the low-risk group, computed tomography angiography (CTA) is preferable. When the risk for CAD is judged to be intermediate (PTP> 15 %) an imaging investigation is advocated instead of the well-established exercise stress bicycle test. A much-used imaging test is myocardial perfusion scan in which an exercise stress bicycle test is performed, with the addition of an intravenous injection of a small amount of radioactive tracer, whereafter the myocardial blood flow is demonstrated by imaging. Sensitivity for myocardial perfusion scan to detect significant CAD is 87 % (95 % CI 83-90) in comparison with exercise stress bicycle test where it is only 58 % (95 % CI 46-69). Specificity is 70 % (95 % CI 63-76) and 62 (95 % CI 54-69) respectively. However, the exercise stress bicycle test reveals indirect signs of myocardial ischemia and is reasonable in price, easy to perform and available in many clinics and hospitals. It is since long the first-line method for referral from the primary care setting. If the result from the exercise stress bicycle test is inconclusive, the work-up should be continued, e.g. with myocardial perfusion scan. An echocardiogram is often performed as well to evaluate the condition of the myocardium, heart valves and left ventricular ejection fraction. This stepwise or sequential clinical work-up strategy is well known and reasonable in general practice where patients in general have a low prevalence of serious diseases compared to organ specialist clinics. Since June 2021 in Region Östergötland (471 912 inhabitants 2022) CTA is recommended if further investigation is deemed necessary in patients with a low risk of CAD (PTP< 15 %) in primary care. For patients with intermediate risk of CAD (PTP> 15 %) exercise stress bicycle test is still the first-line choice.

There may be advantages if myocardial perfusion scan and echocardiogram is performed on a single visit. In addition, a CT scan of the heart to determine coronary artery calcification (CAC) score is easy to perform on the same visit, gives only a small amount of radiation and adds useful information. The CAC-score has been shown to be an independent predictor of future cardiovascular events and is useful for reclassification of cardiovascular risk based on traditional risk factors like age, cholesterol levels and smoking habits. Furthermore, a clear and coherent answer on all three investigations, to the referring GP can provide a more secure basis for clinical decision making. For the individual patient it is probably an advantage to get a thorough investigation done at one single visit and possibly a faster and more valid statement from the investigations by the GP. On the other hand, if many advanced investigations are done unnecessarily, expenses and exposure to radiation will increase unjustifiably. Possibly there is also a risk of medicalization and to create worries for future cardiovascular events communicating the CAC-score to people that has not asked for the information.

In order to get a faster and more complete basis for the evaluation of CAD in primary care patients with an intermediate (PTP> 15 %) risk the investigators created a package investigation comprised of myocardial perfusion scan, echocardiogram and CT scan of the heart on a single visit. The results from myocardial perfusion scan will be written according to national guidelines and communicated to the referring GP together with results from echocardiogram and CAC-scoring as a coherent answer. Moreover, registration of heart sounds followed by risk calculation by a technical device Cadscore® will be performed but only for scientific analyzes and not be given as a clinical answer.

In this study the investigators aim to compare the standard routine sequential investigation for detecting CAD with a single-visit package investigation.

Inclusion criteria

• People who seek primary care for symptoms judged to be compatible with a medium probability (PTP> 15) for symptomatic chronic coronary artery disease.

Exclusion criteria

• Suspicion of acute coronary syndrome when care is sought.
• Previously diagnosed acute myocardial infarction
• Revascularization with PCI/CABG
• Proven reversible ischemia according to myocardial scintigraphy.
• Left Bundle Branch Block (LBBB).
• Ventricular pacemaker
• People whose meaning due to illness, mental disorder, weakened state of health or any other similar condition cannot be obtained, to be included in a research project.
• Insufficient understanding of spoken and written Swedish language.