New Horizons in Type 2 Myocardial Infarction

Pathogenesis, Assessment and Management of an Emerging Geriatric Disease

Alain Putot; Sophie Putot; Frédéric Chagué; Yves Cottin; Marianne Zeller; Patrick Manckoundia

Disclosures

Age Ageing. 2022;51(4):afac085 

In This Article

Abstract and Introduction

Abstract

Type 2 myocardial infarction (MI) is characterised by a functional imbalance between myocardial oxygen supply and demand in the absence of a thrombotic process, leading to myocardial necrosis. This type of MI was relatively unknown among clinicians until the third universal definition of MI was published in 2017, differentiating Type 2 from Type 1 MI, which follows an acute atherothrombotic event. The pathogenesis, diagnostic and therapeutic aspects of Type 2 MI are described in the present review. Type 2 MI is a condition that is strongly linked to age because of vascular ageing concerning both epicardic vessels and microcirculation, age-related atherosclerosis and stress maladaptation. This condition predominantly affects multimorbid individuals with a history of cardiovascular disease. However, the conditions that lead to the functional imbalance between oxygen supply and demand are frequently extra-cardiac (e.g. pneumonia or anaemia). The great heterogeneity of the underlying etiological factors requires a comprehensive approach that is tailored to each case. In the absence of evidence for the benefit of invasive reperfusion strategies, the treatment of Type 2 MI remains to date essentially based on the restoration of the balance between oxygen supply and demand. For older co-morbid patients with Type 2 MI, geriatricians and cardiologists need to work together to optimise etiological investigations, treatment and prevention of predisposing conditions and precipitating factors.

Introduction

Myocardial infarction (MI) is a condition that is particularly frequent in older patients: more than half of MIs and about 80% of deaths related to ischemic heart disease occur after age 65.[1]

MI is the consequence of the development of atheromatous disease within the coronary arteries, a phenomenon strongly correlated with age. Autopsy data have shown that significant coronary artery disease occurs in >70% of patients over 70 years of age.[2] Because coronary arteries are essentially functional end arteries, the complete or partial occlusion of one of them usually leads to ischemia of the downstream territory. In the majority of cases, MI is therefore related to an acute atherothrombotic phenomenon within the coronary network. However, this is not the only possible pathophysiological mechanism. In 20% of cases, historical autopsy data of acute MI do not find thrombosis in the coronary artery vascularizing the infarcted territory despite a scrupulous microscopic analysis of each coronary segment.[3] The notion of MI not linked to a phenomenon of mechanical coronary occlusion but to a situation of functional imbalance between oxygen supply and demand, known as Type 2, which only appeared recently in the universal definition of MI.[4] Despite its frequency, particularly in older patients, Type 2 MI remains largely unknown to clinicians. The concept of a multifactorial functional imbalance at the origin of an acute pathological situation is profoundly linked to geriatric medicine,[5] and the care of these patients should thus not be limited exclusively to a cardiological approach. We will review in the present article the main epidemiological and pathophysiological features of Type 2 MI as well as the diagnostic, therapeutic and preventive aspects in clinical practice.

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