Tag Archives: myocardial infarction

Myocardial Infarction- Third Universal definition and classification

Definition of myocardial infarction

Criteria for acute myocardial infarction :

The term acute myocardial infarction (MI) should be used when there is evidence of myocardial necrosis in a clinical setting consistent with acute myocardial ischaemia. Under these conditions any one of the following criteria meets the diagnosis for MI:

Detection of a rise and/or fall of cardiac biomarker values [preferably cardiac troponin (cTn)] with at least one value above the 99th percentile upper reference limit (URL) and with at least one of the following:

  1. Symptoms of ischaemia.
  2. New or presumed new significant ST-segment–T wave (ST–T) changes or new left bundle branch block (LBBB).
  3. Development of pathological Q waves in the ECG.
  4. Imaging evidence of new loss of viable myocardium or new regional wall motion abnormality.
  5. Identification of an intracoronary thrombus by angiography or autopsy.

•Cardiac death with symptoms suggestive of myocardial ischaemia and presumed new ischaemic ECG changes or new LBBB, but death occurred before cardiac biomarkers were obtained,or before cardiac biomarker values would be increased.

• Percutaneous coronary intervention (PCI) related MI is arbitrarily defined by elevation of cTn values (>5 x 99th percentile URL) in patients with normal baseline values (≤99th percentileURL) or a rise of cTnvalues >20% if the baseline values are elevated and are stable or falling. Inaddition,either(i)symptoms suggestiveof myocardialischaemia or (ii) new ischaemic ECG changes or (iii) angiographicfindings consistent with a proceduralcomplication or (iv) imaging demonstration of new loss of viable myocardium or new regional wall motion abnormality are required.

• Stent thrombosis associated with MI when detected by coronary angiography or autopsy in the setting of myocardial ischaemia and with a rise and/or fall of cardiac biomarker values with at least one value above the 99th percentile URL.

• Coronary artery bypass grafting (CABG) related MI is arbitrarily defined by elevation of cardiac biomarker values (>10 x 99th percentile URL) in patients with normal baseline cTn values (≤99th percentile URL). In addition, either (i) new pathological Q waves or new LBBB,or (ii) angiographic documented new graft or new native coronary artery occlusion, or (iii) imaging evidence of new loss of viable myocardium or new regional wall motion abnormality.

Criteria for prior myocardial infarction

Any one of the following criteria meets the diagnosis for prior MI:

• Pathological Q waves with or without symptoms in the absence of non-ischaemic causes. • Imaging evidence of a region of loss of viable myocardium that is thinned and fails to contract,in the absence of a non-ischaemic cause.

• Pathological findings of a prior MI

 UNIVERSAL CLASSIFICATION OF MYOCARDIAL INFARCTION

Type 1: Spontaneous myocardial infarction

Spontaneous myocardial infarction related to atherosclerotic plaque rupture, ulceration, fissuring, erosion, or dissection with resulting intraluminal thrombus in one or more of the coronary arteries leading to decreased myocardial blood flow or distal platelet emboli with ensuing myocyte necrosis. The patient may have underlying severe CAD but on occasion non-obstructive or no CAD.

Type 2: Myocardial infarction secondary to an ischaemic imbalance

In instances of myocardial injury with necrosis where a condition other than CAD contributes to an imbalance between myocardial oxygen supply and/or demand, e.g.coronary endothelial dysfunction, coronary artery spasm, coronary embolism, tachy-/brady-arrhythmias, anaemia, respiratory failure, hypotension, and hypertension with or without LVH.

Type 3: Myocardial infarction resulting in death when biomarker values are unavailable

Cardiac death with symptoms suggestive of myocardial ischaemia and presumed new ischaemic ECG changes or new LBBB, but death occurring before blood samples could be obtained, before cardiac biomarker could rise, or in rare cases cardiac biomarkers were not collected.

Type 4a: Myocardial infarction related to percutaneous coronary intervention (PCI)

Myocardial infarction associated with PCI is arbitrarily defined by elevation of cTn values >5 x 99th percentile URL in patients with normal baseline values (£99th percentile URL) or a rise of cTn values >20% if the baseline values are elevated and are stable or falling. In addition, either (i) symptoms suggestive of myocardial chaemia, or (ii) new ischaemic ECG changes or new LBBB, or (iii) angiographic loss of patency of a major coronary artery or a side branch or persistent slow- or no-flow or embolization, or (iv) imaging demonstration of new loss of viable myocardium or new regional wall motion abnormality are required.

Type 4b: Myocardial infarction related to stent thrombosis

Myocardial infarction associated with stent thrombosis is detected by coronary angiography or autopsy in the setting of myocardial ischaemia and with a rise and/ or fall of cardiac biomarkers values with at least one value above the 99th percentile URL.

Type 5: Myocardial infarction related to coronary artery bypass grafting (CABG)

Myocardial infarction associated with CABG is arbitrarily defined by elevation of cardiac biomarker values >10 x 99th percentile URL in patients with normal baseline cTn values (£99th percentile URL).In addition,either (i) new pathological Q waves or new LBBB,  or (ii) angiographic documented new graft or new native coronary artery occlusion, or (iii) imaging evidence of new loss of viable myocardium or new regional wall motion abnormality

MI rates with Ticagrelor (from PLATO)

This article in JACC examines the rates of MI in patients with ACS treated with ticagrelor vs clopidogrel.

The rates of overall MI at 12 months:

1. Ticagrelor- 5.8%

2. Clopidogrel – 6.9%

3. Nonprocedural MI (HR: 0.86; 95% CI: 0.74 to 1.01) and MI related to percutaneous      coronary intervention or stent thrombosis tended to be lower with ticagrelor.

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