Consensus on the diagnosis and management of patients with type 2 myocardial infarction: an international Delphi study

Abstract Background Type 2 myocardial infarction occurs due to a reduction in myocardial oxygen supply or an increase in demand without evidence of atherosclerotic plaque rupture. It is common representing around 20% of myocardial infarctions (1-4). Outcomes are poor with up to one third alive at five years, with cardiovascular outcomes comparable to type 1 myocardial infarction (1,5,6). Despite this, there are no evidence-based guidelines to guide assessment and management for clinicians. Purpose To gain consensus on the assessment and management of type 2 myocardial infarction from an international group of experts. Methods A systematic review of type 2 myocardial infarction was undertaken to identify the corresponding or senior author of all original research studies. We identified 73 experts from multiple clinical specialties. A three-round international eDelphi study was circulated, with round one consisting of open questioning to generate statements for deductive analysis. Consensus was defined a priori as >70% agreement on a 5-point Likert scale. Statements for which no consensus could be obtained were adapted and recirculated in round three (Figure 1). Results Of the 68 experts contacted there was a 56% (38/68), 54% (37/68) and 72% (49/68) response rate in round one, two and three, respectively. Consensus was achieved on 64% (43/67) of statements. Consensus varied across the following domains i) definition and diagnosis 42% (5/12), ii) risk stratification 75% (3/4), iii) assessment of coronary artery disease and cardiac function 50% (9/18), iv) specialty management 60% (6/10), v) treatment and secondary prevention 100% (9/9) and vi) communication and rehabilitation 79% (11/15). The panel agreed that all patients should undergo echocardiography (mean [SD] 2.08 [1.23]) and CT coronary imaging or a functional test should be performed on those with intermediate probability of future cardiovascular events (mean [SD] 1.81 [0.52]). Over 90% of the panel agreed that both patient and clinician understanding of type 2 myocardial infarction was poor and that further randomised controlled trials are need to direct care. Conclusion There remains uncertainty regarding the current definition of type 2 myocardial infarction and overall patient and clinician understanding was thought to be poor. However, it is generally accepted that the mainstay of management should be on the identification of coronary artery disease and left ventricular impairment with optimisation of therapies with proven benefit. Management should involve an individualised assessment and the multidisciplinary team.