Type 2 myocardial infarction due to supply–demand mismatch
Section snippets
Definition
The Universal Definition defines MI based on a rise and/or fall of cardiac biomarkers, preferably cardiac troponin (cTn) I or T, above the 99% of a normal reference population in conjunction with evidence consistent with MI from symptoms, imaging, electrocardiogram, or angiography [1]. Further, diagnosis of T2MI requires a clinical history suggestive of myocardial necrosis caused by an identifiable cause of supply/demand mismatch (Table 2). While some have called for diagnostic criteria for
Epidemiology
Epidemiologic understanding of T2MI is limited by the relatively recent introduction of the classification scheme, areas of uncertainty in the Universal Definition diagnostic criteria, and largely retrospective nature of existing evidence.
In retrospective cohort studies of patients, a cohort first identified by biomarker elevation then adjudicated for the clinical diagnosis of MI, the proportion of T2MI (amongst all MIs) varies widely, ranging from 2% to 30% (Table 3) [2], [3], [4], [5], [6],
Pathophysiologic considerations
The pathophysiology of T2MI reflects myocardial ischemia with necrosis resulting from either increased myocardial oxygen demand and/or decreased myocardial oxygen delivery. Often, both processes are involved in varying proportions. Myocardial oxygen demand is determined by systolic wall tension, contractility, and heart rate, while myocardial oxygen supply is determined by coronary blood flow and its oxygen carrying capacity [18]. Conditions that increase oxygen demand include supraventricular
Diagnosis and clinical presentation
Although the clinical history and symptoms of patients presenting with type 1 or T2MI can be similar. A higher proportion of patients with, some differences are observed (Table 5) type 1 MI report chest pain compared with those presenting with T2MI (89% vs. 51%), while there are no significant differences between type 1 MI and T2MI patients presenting with shortness of breath [13]. T2MI patients typically have an alternative diagnosis leading to their presentation and serving as the cause of
Biomarkers of myocardial necrosis in T2MI
The Universal Definition depends on an elevation and a rise or fall of cardiac biomarkers, with cardiac troponin preferred over the myocardial band of creatine kinase isoenzyme (CK-MB). An elevated troponin that does not change significantly over time suggests chronic myocardial injury. Conventional assays for troponin measurement (with first-draw sensitivity of 70–80% for detecting MI) on presentation are being widely replaced by troponin assays with substantially greater sensitivity in Europe
Angiography to evaluate T2MI
When compared to type 1 MI, patients with T2MI are less likely to undergo coronary angiography [6], [9]. This may reflect a selection bias against angiography in patients with a clinical diagnosis of T2MI in addition to the unclear role for percutaneous intervention in the absence of acute plaque rupture. Given the older age and increased number of comorbidities in patients with T2MI, a concern for post-procedural complications may also influence the frequency of coronary angiography.
Coronary
Prognosis
Despite controversies in precise categorization, prognostic significance of T2MI is clear. In the CASABLANCA study, over a median follow-up of 3.4 years, 152 patients had at least one T2MI [11]. Patients with T2MI developed adverse events significantly more frequently compared with those without T2MI (per 100 person/years: major cardiovascular events, 53.7 vs. 21.1, p < 0.001; all-cause death, 23.3 vs. 3.3, p < 0.001; cardiovascular death, 17.5 vs. 2.6, p < 0.001; heart failure events, 22.4 vs.
Treatment
Treatment of T2MI is complicated by the lack of prospective evidence and therefore established guidelines. Correction of the underlying cause of supply/demand mismatch remains the primary mainstay of management. Reflecting the difficulties in clinical discernment between type 1 and T2MI and the tendency to initiate type 1 MI guideline-supported therapy for T2MI, the use of intravenous and subcutaneous anticoagulants may not differ between type 1 and T2MI [6].
Although little prospective evidence
Conclusion
Since 2007 when the Universal Definition of Myocardial Infarction introduced the subclassification of T2MI, interest has focused on this increasingly incident and highly morbid form of MI. With global introduction of high-sensitivity troponin assays, the recognized incidence of T2MIs will likely increase. While associated with considerable risk (comparable to that of type 1 MI, which has well-defined management strategies), the spectrum of potential etiologies for T2MI makes development of
References (41)
- et al.
Third universal definition of myocardial infarction
J Am Coll Cardiol
(2012) - et al.
Mortality rate in type 2 myocardial infarction: observations from an unselected hospital cohort
Am J Med
(2014) - et al.
Classification of myocardial infarction: frequency and features of type 2 myocardial infarction
Am J Med
(2013) - et al.
Frequency of elevated troponin I and diagnosis of acute myocardial infarction
Am J Cardiol
(2009) - et al.
The impact of the 2007 ESC-ACC-AHA-WHF Universal definition on the incidence and classification of acute myocardial infarction: a retrospective cohort study
Int J Cardiol
(2010) - et al.
Supply/demand type 2 myocardial infarction: should we be paying more attention?
J Am Coll Cardiol
(2014) - et al.
Coronary plaque rupture in patients with myocardial infarction after noncardiac surgery: frequent and dangerous
Atherosclerosis
(2012) - et al.
Perioperative cardiovascular risk of prior coronary stent implantation among patients undergoing noncardiac surgery
J Am Coll Cardiol
(2016) - et al.
Cardiac troponin after major vascular surgery: the role of perioperative ischemia, preoperative thallium scanning, and coronary revascularization
J Am Coll Cardiol
(2004) - et al.
Postoperative myocardial ischemia: etiology of cardiac morbidity or manifestation of underlying disease?
J Clin Anesth
(1995)
Diagnostic and therapeutic implications of type 2 myocardial infarction: review and commentary
Am J Med
Pathobiology of troponin elevations: do elevations occur with myocardial ischemia as well as necrosis?
J Am Coll Cardiol
Sepsis-associated myocardial dysfunction: diagnostic and prognostic impact of cardiac troponins and natriuretic peptides
Chest
Role of interleukin 6 in myocardial dysfunction of meningococcal septic shock
Lancet
Preparing the United States for high-sensitivity cardiac troponin assays
J Am Coll Cardiol
Angiographic correlates in type 1 and 2 MI by the universal definition
JACC Cardiovasc Imaging
Patients with left main coronary artery vasospasm inadvertently undergoing coronary artery bypass grafting surgery
J Am Coll Cardiol
Cardiac troponin changes to distinguish type 1 and type 2 myocardial infarction and 180-day mortality risk
Eur Heart J Acute Cardiovasc Care
Type 2 myocardial infarction in clinical practice
Heart
Effect of the novel thienopyridine prasugrel compared with clopidogrel on spontaneous and procedural myocardial infarction in the trial to assess improvement in therapeutic outcomes by optimizing platelet inhibition with prasugrel-thrombolysis in myocardial infarction 38: an application of the classification system from the universal definition of myocardial infarction
Circulation
Cited by (20)
Prospective cardiovascular evaluation with 24-hour Holter and 24-hour ambulatory blood pressure monitoring in men using 5-mg oral minoxidil for androgenetic alopecia
2023, Journal of the American Academy of DermatologyMolecular targets for the treatment of angina pectoris
2023, Nanotechnology Principles in Drug Targeting and DiagnosisEditorial commentary: Improving our understanding of type 2 myocardial infarction and myocardial injury
2017, Trends in Cardiovascular MedicineNon-coding RNAs as therapeutic targets and biomarkers in ischaemic heart disease
2024, Nature Reviews CardiologyEffect of Implementing an Educational Program on Lifestyle Practices among Patients with Coronary Artery Disease
2023, International Egyptian Journal of Nursing Sciences and ResearchPost-infectious ST elevation myocardial infarction following a COVID-19 infection: A case report
2022, Biomedical Reports
The authors have indicated there are no conflicts of interest.
Funding: Dr. Gaggin is supported in part by the Clark Fund for Cardiac Research Innovation, Dr. Januzzi is supported in part by the Hutter Family Professorship.
Relationship with industry: Dr. Januzzi reports the following disclosures: (1) Roche Diagnostics: research grants, consultancy; (2) Siemens Diagnostics: research grants; (3) Prevencio: research grants; (4) Singulex: research grants; (5) Critical Diagnostics: consultancy; (6) Philips: consultancy; (7) Novartis: clinical endpoints committee, consultancy; (8) Boehringer-Ingelheim: clinical endpoints committee, consultancy; and (9) Amgen: data monitoring committee.
Dr. Gaggin reports the following disclosures: (1) Roche Diagnostics: research grant, consultancy; (2) Portola: research grant; (3) Amgen: consultancy; (4) American Regent: consultancy; (5) Boston Heart Diagnostics: consultancy; (6) Critical Diagnostics: consultancy; (7) EchoSense: clinical endpoint committee; (8) Radiometer: clinical endpoint committee; and (9) Ortho Clinical: consultancy.
Dr. Mihatov does not have any disclosures.