Duration of Ischemia Is a Major Determinant of Transmurality and Severe Microvascular Obstruction After Primary Angioplasty

We read with great interest the recently published article in the October 2016 issue of JACC Cardiovasc Interv by Rashid et al. (1). Briefly, it was a retrospective, single center study that analyzed ST-elevation myocardial infarction (STEMI) patients with symptom onset <12 hours. Patients with primary percutaneous intervention (PCI) were compared with those who received fibrinolytic therapy prior to arrival at the hospital due to non-availability of primary PCI. The authors concluded that the pharmaco-invasive strategy was associated with similar rates of the composite endpoint of mortality, reinfarction, or stroke as compared with a primary PCI strategy. There was propensity for increased bleeding in the pharmaco-invasive group, with a significant fraction (approximately 1 in every 21 patients) having major bleeding, including intracranial bleeding.Non-inferiority of pharmaco-invasive strategy compared to primary PCI strategy in this study emphasizes the importance of total ischemic time. These are patients who received fibrinolytic therapy within few minutes of presentation at the initial hospital (with no primary PCI capability) which could have led to dissolution of the thrombus and re-canalization of the culprit artery, and hence reduction of the total ischemic time. The similar outcomes between the groups despite a big difference in the door-to-balloon times are most likely due to the shortening of the total ischemic time by the administration of fibrinolysis. However, we must not ignore the limitations of the study. There was a disparity between the control group vs. test group, i.e., 236 pharmaco-invasive strategy patients vs. 980 primary PCI patients (approximately 4:1 ratio), which may have influenced the statistical model. As the patients were not randomized, unknown confounders may have affected the results owing to the retrospective nature of the study. For example, the median time from symptom onset to arrival at the first hospital was significantly shorter in the pharmacoinvasive group, which may have favored these patients. The study only studied the in-hospital results and the long-term outcomes are not known. The infarct size as measured by peak creatinekinase MB levels, was significantly higher in pharmacoinvasive group, and we already know that the peak infarct size is related to worse long-term outcomes from several large trials in the past (2). However, this difference may not be clinically significant as the composite of mortality, reinfarction, or stroke was similar between the two groups. Nevertheless, the long-term outcomes are unknown in these patients. Also, the infarct zone at risk was not defined so that the selection bias for patients who were destined to have larger infarcts was not eliminated. To better define the zone at risk an MRI study like the one done by Eitel et al. would have been very useful (3). Furthermore, the pharmacologic regimen used for the groups were different. The pharmaco-invasive group patients received a lower dose of clopidogrel and an infusion of heparin...

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“…For every 30 minutes of treatment delay, there was a 37% increased risk of transmural necrosis (11).…”

Section: Ormentioning

confidence: 99%

The relationship between total ischemic time and mortality in patients with STEMI: every second counts

Khalid

Jneid

Denktaş

2017

Cardiovasc. Diagn. Ther.

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“…The rate of the progression of LV systolic dysfunction and its clinical manifestation -heart failure -is determined by the degree and duration of myocardial ischemia, stunning myocardium, the damaged area of the myocardium, the localization of the damage, the degree of infarct-related coronary artery lesion, and changes in the myocardium prior to ACS (8)(9)(10)(11). In the presence of myocardial changes, the course of LV systolic dysfunction is related to the myocardial remodeling process and its consequences, dilatation of cardiac chambers, mitral regurgitation, and diastolic dysfunction.…”

Section: Discussionmentioning

confidence: 99%

Prognostication of late left ventricular systolic dysfunction in patients with acute coronary syndrome during the acute period

Babarskienė¹,

Venclovienė

Lukšienė

et al. 2007

Medicina

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“…Kim et al questioned whether there is a correlation between delayed contrast enhancement and the age of myocardial infarction, as well as the use of CMR to detect viability and irreversible lesions and evaluate the contractile function of the myocardium. [21][22][23][24] The theory was tested on canine models, and their results revealed that in the first 24 hours from the infarction, hyperenhancement occurs both in the necrosis zone and at the borderline that includes the hibernating myocardium. In terms of chronic infarction, the contrast agent has a strict affinity for the fibrosis area, and the imaging delineation of the hibernated myocardium from the necrosis area is a real challenge.…”

Section: Clinical Applications Of Cmrmentioning

confidence: 99%

Magnetic Resonance Imaging in Myocardial Fibrosis Related to Ischemic Events

Himcinschi¹,

Beganu²,

Bordi³

et al. 2017

Journal of Interdisciplinary Medicine

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Given the higher amount of detail it offers, the use of magnetic resonance (MR) in the field of cardiology has increased, thus leading to a decrease in the use of invasive and irradiating methods for diagnosing various cardiovascular disorders. The only precautions for MR imaging are metallic implants and advanced-stage chronic kidney disease. For the acquisition of clear and dynamic myocardial images, methods such as spin echo imaging for anatomical description, steady-state free precession imaging for the assessment of ventricular cavity size and function, flow velocity encoding for blood flow measurements, radiofrequency tagging for dynamics, and even spectroscopy for metabolism evaluation are used. Cardiac magnetic resonance (CMR) is considered the gold standard imaging method for the anatomical characterization of the heart and obtaining information related to myocardial dynamics. In case of ischemic events, CMR is used for a detailed description of the necrotic area and the complications, and for tracking the ventricular remodeling. By administrating a contrast agent (gadolinium), the difference between sub-endothelial and transmural infarctions can be distinguished, highlighting even microvascular lesions responsible for the extension of the necrosis. The assessment of the dynamics of ventricular remodeling and viability through late gadolinium enhancement (LGE) technology highlights the area of fibrosis and the occurrence of late complications.

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Duration of Ischemia Is a Major Determinant of Transmurality and Severe Microvascular Obstruction After Primary Angioplasty

Abstract: In AMI patients with impaired coronary perfusion undergoing PCI, the risk of TN and SMO increases with the duration of the ischemic time.

Cited by 205 publications

References 36 publications

The relationship between total ischemic time and mortality in patients with STEMI: every second counts

The relationship between total ischemic time and mortality in patients with STEMI: every second counts

Prognostication of late left ventricular systolic dysfunction in patients with acute coronary syndrome during the acute period

Magnetic Resonance Imaging in Myocardial Fibrosis Related to Ischemic Events

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