Time to cardiovascular magnetic resonance imaging influences diagnostic yield in patients with suspected myocardial infarction with nonobstructive coronary arteries: a meta-analysis

Objectives To conduct a systematic review and meta-analysis to assess the evidence of cardiovascular magnetic resonance imaging (CMR) in patients with suspected myocardial infarction and nonobstructive coronary arteries (MINOCA), and how time to CMR influences diagnosis. Background CMR is indicated in patients with suspected MINCOA but it is unclear when is best to perform the CMR and how this timing can influence diagnosis. Methods We systematically conducted a comprehensive literature search to identify relevant studies. These studies were assessed to determine the study quality and analysis was performed using a Random-effects model. Results There were 23 eligible studies, including 4,231 patients. The mean quality score was 9.35 out of 10. For MINOCA patients assessed by CMR, the average median time from presentation to CMR was 12.50 days (SD: 14 days, range 0-365 days). The pooled frequencies of the most common diagnoses were: myocarditis (29%), myocardial infarction (22%), Takotsubo syndrome (10%), cardiomyopathy (7%), and 22% had no cardiac diagnosis (normal CMR findings). In pooled analysis, the prevalence of normal CMR findings increased by three percentage points for each extra day of waiting between presentation and CMR scanning over the studied range of 0-14 days (Slope: 3.1 %-points/day; r=0.67, p=0.003). Conclusions In patients with suspected MINOCA, the longer it takes a patient to have a CMR scan, the more likely the results will be normal and no diagnosis made by CMR. CMR should be performed as early as possible in suspected MINOCA. Highlights In patients with suspected MINOCA, the pooled frequency of diagnoses made by CMR include myocarditis (29%), myocardial infarction (22%), Takotsubo syndrome (10%), cardiomyopathy (7%), and no diagnosis/normal study (22%). The longer it takes to have a CMR scan the more likely the patient will have a normal scan. In patients with suspected MINOCA, CMR scanning should be performed as soon as possible.