Troponin-positive chest pain with unobstructed coronary arteries: definitive differential diagnosis using cardiac MRI

Abstract

Objective: The purpose of this study was to assess the outcome of cardiac MRI (CMRI) with late gadolinium enhancement (LGE) at outpatient follow-up in a consecutive series of patients with troponin-positive chest pain but unobstructed coronary arteries at the index admission. Methods: The study group comprised 91 consecutive patients who presented to our institution with cardiac chest pain, elevated troponin I and unobstructed coronary arteries on coronary angiography. All patients underwent an outpatient CMRI with LGE imaging in order to establish a definitive diagnosis. Results: The average time from coronary angiography to LGE-CMRI was 2 months. 73% of patients had no abnormality on their LGE-CMRI, 16% of patients had patchy late enhancement consistent with myocarditis and 11% had focal subendocardial or full thickness late enhancement consistent with myocardial infarction. There were no deaths in this cohort during a mean follow-up of 21 months. Conclusion:LGE-CMRI is a useful tool for establishing whether such patients have definitive evidence of non-ST-segment elevation myocardial infarction (NSTEMI), and can make an important contribution to the long-term management strategy of these patients as an inappropriate diagnosis of NSTEMI carries important medical, social and financial implications.

Imaging diagnoses and outcome in patients presenting for primary angioplasty but no obstructive coronary artery disease

“…Studies that have mainly focused on the usefulness of CMR in patients with normal angiograms, without reference to the total number of patients with culprit-free angiograms, usually report a much higher prevalence of myocarditis, varying between 50% and 80%, 8 9 26 although one study reports a prevalence of 16%. 10 A study by Larson et al,4 which is more similar to ours demonstrated myocarditis in 19% of patients. However, the prevalence of clinical myocarditis is likely to be higher as CMR criteria have a sensitivity of up to 70%.…”

“…6 7 In the last few years, there has been an increasing interest in alternative causes of acute chest pain associated with troponin rise particularly with non-invasive diagnosis of myocarditis on cardiac magnetic resonance (CMR) or demonstration of myocardial infarction (MI) in the presence of recanalised arteries. [8][9][10] However, such studies have mainly focused on small series of patients presenting within a broader spectrum of acute coronary syndrome (ACS) with raised troponin with the aim of evaluating the usefulness of CMR. The prevalence of non-coronary causes of acute chest pain and their prognosis, particularly those presenting with suspected STEMI, is less well described.…”

Prognostic Role of CMR and Conventional Risk Factors in Myocardial Infarction With Nonobstructed Coronary Arteries

“…(11)(12)(13)(14)(15)(16)(17) However, the diagnostic yield of CMR in the literature was disparate, ranging from as low as 30% to as high as 90%. (11)(12)(13)(14)(15)(16)(17) The variation in the diagnostic yield in the literature can be explained by the use of incomplete CMR protocol (oedema imaging not always included) as well as the timing of the test, sometimes occurring several months after the acute event leading to the resolution of the reversible cardiac abnormalities. (13,18) In our cohort, the most common diagnosis was MI (25%, n=97), closely followed by myocarditis (25%, n=96) and cardiomyopathy (25%).…”

“…Few previous studies have shown that CMR can identify the underlying diagnosis, most commonly: acute/chronic myocarditis, acute MI with spontaneous recanalization/embolus, stress cardiomyopathy (Takotsubo) or other cardiomyopathies. (11)(12)(13)(14)(15)(16)(17) Only in a small proportion of cases, no abnormality is identified by CMR. The variable proportion of normal cases in the different studies may be due to the time delay between the acute presentation and CMR, (18) suggesting that the time between acute presentation and CMR can play a role in identifying the early reversible abnormalities that may resolve when patients are scanned later.…”

Management and Outcomes in Patients with a Diagnosis of Myocardial Infarction but with Normal Coronary Arteries Angiographically

“…In such patients plaque rupture may have occurred but the coronary angiogram reveals a stenosis of less than 50% therefore making the diagnosis of an acute coronary syndrome (ACS) difficult. The mechanism includes arterial occlusion and recanalisation, coronary spasm or embolism [5]. There is a lack of data regarding the management of these patients and in addition often a small number of patients have been recruited.…”