notes by dr. Claudio Italiano
It would be more appropriate, however, to speak about Acute Coronary Syndrome,
NSTEMI and STEMI, that is, respectively, with Non ST
elevated and elevated ST , this latter condition is much more serious.
The ECG must be performed within 10 min from the arrival of the patient in the
emergency room or, better still, at the time of first contact with the emergency
service in the prehospital environment, and must be immediately interpreted by a
qualified doctor.
In the context of a ACS NSTEMI, the ECG may be normal in over a third of patients; vice versa, the typical alterations consist of a depression of the ST tract, a transitional overlapping of the ST tract and changes of the T wave.
A troponin dosage is immediately taken to follow; if the troponins are elevated it means that the heart muscle is in necrosis and is releasing them in the circulation where they normally do not have to be present. In patients with MI there is a rapid elevation of cardiac troponin concentrations after the onset of symptoms (generally detectable within 1 h when high sensitivity tests are used), which persists for a certain period of time (usually for a few days).
Fortunately, today we have clearer ideas about the management of the patient
with myocardial infarction (AMI). The definition of acute myocardial infarction
(MI) indicates the presence of myocitonecrosis in the context of an evocative
clinical picture of acute myocardial ischemia.
In patients with ST-segment elevation myocardial infarction, first PCI (Percutaneous
coronary intervention ) should be the treatment of choice when the hospital is
equipped with a haemodynamic room for PCI and sufficiently experienced
personnel.
Patients with contraindications to thrombolysis (therapy that dissolves the thrombus of the coronary arteries) should be transferred immediately to make a PCI, as this may be their only chance of rapid reopening of the coronary artery.
Intra-hospital mortality for AMI has decreased enormously: from 25-30% of the
60s to 18% of the early 1980s; between the end of the 80s and the beginning of
the 90s it gradually fell to below 10% and then, at present, fell to 5-6%.
This has been made possible thanks to the introduction and diffusion of the ICUs, ie the Coronary Intensive Care Unit (ICU) and, even more, of the Hemodynamics Units, ie those services present in the Major Hospitals that allow acute treatment of the patient through the implementation of PTCA, ie angioplasty, ie a technique by which, through the femoral artery or radial artery, the aorta and coronary arteries are reached to unravel them from the atheromatous plaques, ie to clean them from the callous and calcified stenoses that in the meantime they have been created, positioning STENT, that is as if they were "springs", to prevent the coronary collapsing again. Today, stents are also medicated with anti-aggregating substances.
Another classic situation of first aid, the patient who arrives with a
chest
pain (acute coronary syndrome) and with an ECG Non ST elevated, such as for
unstable angina condition.
What to do in this case?
Non elevated ST- ACSs include a spectrum of clinical manifestations ranging from absence of symptoms to presenting evidence of ongoing ischemia, electrical instability or hemodynamics, to cardiac arrest.
From an anatomo-pathological point of view, they are characterized at the myocardyal tissue by areas of cardiomyocytic necrosis (myocardial infarction without ST segment elevation [NSTEMI]) or, less frequently, by myocardial ischemia unaccompanied by cell loss (unstable angina).
In patients with ACS-NSTE, anginal pain may therefore occur as:
• prolonged anginal pain at rest (> 20 min);
• new onset angina (de novo) (class II-III of the Canadian Cardiovascular
Society);
• recent state of instability of a previous stable angina with characteristics
attributable to at least class III of the Canadian Cardiovascular Society
(angina in crescendo); or
• post-infarct angina.
Patients with acute coronary syndrome without ST-segment elevation (unstable
angina or ST-segment elevated myocardial infarction) should first be stratified
based on the risk of acute thrombotic complications. Clear benefit has been
shown in the case of early coronary artery disease (<48 hours) and, when
necessary, for PCI or CABG (coronary artery bypass) only in high-risk patients.
These are equally treated in the hemodynamic room.
Risk criteria that impose the choice of an invasive
strategy in patients with acute coronary syndrome without ST-segment elevation.
Very high risk criteria • Haemodynamic instability or cardiogenic shock
• Chest pain in progress or recurrent refractory to medical therapy
• Potentially fatal arrhythmias or cardiac arrest
• Mechanical complications of the IM
• Acute heart failure
• Recurring dynamic modulations of the ST segment and of the T wave, in
particular with transient elevation of the ST segment. Criteria of high risk
• Elevation or decrease of troponin concentrations suggestive of IM
• Dynamic modifications of the ST segment and T-wave (symptomatic or silent)
• GRACE risk score> 140 Intermediate risk criteria
• Diabetes mellitus
• Renal impairment (eGFR <60 ml / min / 1.73 m2)
• FEVS <40% or congestive heart failure
• Early post-infarct angina
• PCI Priority • CABG Priority •
GRACE risk score between> 109 and <140 Low risk criteria
Any characteristics other than those mentioned above
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Introducer inserted into the femoral artery through a cutaneous entry port at the patient's groin |
|
Hemodynamics room |
From the clinical point of view, the superiority of PCI in AMI with respect to
thrombolysis seems to be particularly relevant for the time interval between 3
and 12 hours after the appearance of chest pain or other symptoms, by virtue of
the best preservation of myocardial tissue. associated with the PCI.
Therefore, by summarizing, the two treatments that the infarct has to perform
are:
- Thrombolysis is a therapy to dissolve the thrombus by fibrinolytic substances in a
situation of hospitalization ICU.
This technique is not recommended and
abandoned today, in the sense that the patient, especially if he has a coronary
syndrome with a ST elevation must immediately go into the hemodynamics room,
to perform the said treatment of percutaneous or PTCA angiopathy, whose acronym is PTCA.
-PTCA (angioplasty) to be performed in Hemodynamic rooms
In the hemodynamic room the procedures that can be implemented are:
- structural intervention
- valvuloplasty (ie restoration of heart valves)
- intramyocardial biopsy
- pericardiocentesis
- vascular intervention
- coronary angioplasty (ie disruption of occluded coronary arteries)
They are mainly catheters that are introduced through a passage created in the
femoral or radial artery. They are:
Pig Tail 6 French catheters (1 french = 0.2mm)
Judkins catheter for left coronary curve 3.5 4.0, 5.0, 6.0
Judkins catheter for right coronary curve 3.5 4.0, 5.0, 6.0
Amplatz catheter for left coronary
Amplatz catheter for right coronary artery
mammary catheter
multipurpose catheter
Presents for PTCA and stenting
balloons for angioplasty: these are special catheters, either compliant or not,
ie with or without calibrated dilation, which mount a balloon that is inflated
even at 10-20 atmospheres to dilate the stenotic coronary, which can also be
calcified.
metal stents
medicated stents (ie with antiplatelet agents) sirolimus, everolimus,
pacllitaxel
basket, umbrella and suction embolic protection systems
The patient, prAMI of the intervention, must perform:
- renal function investigations (azotemia, creatinine, sodium and potassium)
- blood count
- coagulation: INR aPTT
- allergological evaluation
In both cases the time factor is essential: the sooner you intervene, the higher
the success rates, because the amount of saved heart tissue is proportional to
the precociousness of the reperfusion, ie the disruption of the occluded artery
and, indeed, of the blood passage (reperfusion) to reduce the extent of the
infarct. However, if there is a choice between PTCA and thrombolysis, then PTCA
should be preferred because it solves the problem of coronary stenosis.
To achieve the goal of infarcted patient care:
reduce pre-hospital intervention times, already treating it on the territory,
correctly diagnose the AMI and direct the patients well, already from the
territory through the emergency service, and telemedicine.
start a thrombolytic treatment.
directing and transporting the patient "to the right place" (in the most
suitable cardiology structure); -
But what to do, then? Thrombolysis or PTCA?
The coronarographic study and the eventual PTCA must be performed within 72
hours, not immediately. But not immediately. Premature invasive treatment is
associated with worse prognosis!
The decision depends on several factors:
- first of all the time elapsed since the onset of AMI symptoms. Thrombolysis
should be carried out preferably within three hours.
- In the event of an onset of pain for more than 12 hours, both thrombolysis and
PTCA are no longer advantageous. Only in case of cardiogenic shock or severe
heart failure is it still indicated to try the PTCA pathway or of the cardiac
surgery (by-pass), even if late, and it is convenient to immediately transport
the patient in Hemodynamics or Cardiac Surgery.
In all other cases the patient is transported to the nearest hospital or to the
reference ICU, if there is only ICU (intensive cardiology therapy unit).
In the event of pain occurring for more than 6 hours and less than 12, PTCA does
not offer greater advantages than thrombolysis. In fact, there is always the
risk of re-infusing a damaged myocardium exposing to dangerous arrhythmias due
to instability of the necrotic tissue of the myocardium and mechanisms of
re-entry, re-excitation, etc. Thrombolysis remains indicated. The patient is
transported to the nearest hospital or to the reference ICU (without going
through the emergency room) where thrombolysis is performed. The exception of
cardiogenic shock and heart failure, as previously mentioned, is understood.
In case of onset of pain for less than 6 hours, two possible occurrences must be
considered:
A) if the AMI is not at high risk, it is indicated how to proceed with
thrombolysis, transporting the patient directly (it is important to avoid the
passage from the emergency room) in the reference ICU (where thrombolysis must
be performed within 30 minutes) or immediately performing thrombolysis at home
or in an ambulance, if it takes more than 60 minutes to reach the ICU;
B) if AMI is at high risk (anterior, i.e. full interest in the left ventricle
and / or with ST overtravel in 5 or more ECG leads and / or with heart rate
above 100 / min and hypotensive patient with lower blood pressure at 100 mmHg
and / or with other evident signs of haemodynamic impairment), it is indicated
how to proceed with the PTCA, transporting the patient directly in Hemodynamics
(PTCA prAMIria) or, if the Hemodynamics can not be reached in 60 minutes,
passing prAMI from the the nearest hospital or the reference ICU to start PTCA
support and facilitation therapy, PTCA which will then be performed by
transferring the patient to Hemodynamics (facilitated PTCA); the same "facilitation"
therapy can also be started in an ambulance, avoiding intermediate steps.
Trombolysis and PTCA. Despite some conflicting elements, the ADMIRAL and
CADILLAC studies and at least two other studies, STOP-AMI and ISAR 2, indicate
that the combination of stenting with abcixAMIb * could be the most effective
and safe procedure for the treatment of AMI.
When to undertake an invasive initiative during acute coronary syndrome?
Symptomatic or silent recurrent ischemia
Severe recurrent ischemia with overlap ST segment> 2mm
Early post-infarct angina
high levels of troponin
hemodynamic instability
Major ventricular arrhythmias
diabetes mellitus
reduced renal function GFR <60 ml / min
risck score intermediate or high (GRACE-TIMI-AI)
the TIMI index is a simple parameter calculated on the basis of systolic BP and
of the frequency and age at the patient's entrance, which allows a risk
stratification. Es (FC / PA) x (age / 10) squared. For example, a patient with
92 of 150 mmHg of pressure and 70 years of age, we will have 92/150 x 49 = 30
|
Left stenosis of the coronary, flapping, bleeding of the flap and thrombus, right stent inserted |
The treatment of AMI presupposes the restoration of an early myocardial perfusion as early as possible and to maintain it over time. The demonstration that an early recovery of the flow in an occluded coronary artery that underlies an acute myocardial infarction can result in the rescue of myocardium and increase survival has changed the therapeutic approach to acute coronary occlusion with ST elevation.
In fact, in many centers the reperfusion strategy
of choice in patients with acute myocardial infarction has shifted from
thrombolysis to PTCA prAMIria for the demonstrated beneficial effects of this
ulcer on survival, ischemic recurrences (residual ischaemia, reinfarction) and
on bleeding complications. Despite these indisputable advantages, they rebuild
dark areas with regard to reperfusion times and subgroups of patients in whom,
for different reasons, it is not possible to restore an adequate flow (TIMI III)
to guarantee the successful reperfusion and the advantages associated with it.
Recently, moreover, an increasing number of evidence has indicated that a new
class of platelet antiplatelet agents, the GP IIb / IIIa receptor inhibitors,
could reduce acute and distant ischemic events after percutaneous elective and
urgent revascularization procedures.
Make me employed in prevention of ACS
Acute coronary syndrome with under-stratified ST
What drugs to use in the prevention of ACS, according to the guidelines?
ASA level evidence A (ie accepted on the basis of double-blind trials etc.)
heparin level evidence A
clopidogrel level evidence A
beta-blocker, level of evidence B, reduce the progression to infarction by 13%
nitrates (level of evidence C)
Acute coronary syndrome with under-stratified ST
In Acute Coronary Syndrome with Undersized ST the treatment presupposes a
precise stratification of the risk; initiated the correct pharmacological
treatment, in 10% of cases the invasive approach represents an emergency.
Coronary angiography or PTCA should be performed within 24 or 72 hours after the
beginning of the symptomatology, after appropriate pharmacological preparation.
Acute coronary syndrome with suprasliveled ST
Here the subject changes: the time effect is fundamental for the prognosis quoad
vitam. The perfusion treatment must be implemented as soon as possible.
Antiaggregation with clopidogrel
Clopidogrel can be given to:
• patients who have had a myocardial infarction; treatment with clopidrogrel can
start in the days immediately after AMI and lasts a maximum of 35 days;
• patients recovering from recent ischemic stroke (non-haemorrhagic stroke);
treatment with clopidrogrel may start within 7 days after the ictal episode and
lasts a maximum of 6 months;
• patients with AOCP peripheral obliterative arterial disease (problem of blood
circulation in the arteries);
• patients with a disorder known as acute coronary syndrome, which is given with
aspirin (another anticoagulant), including patients who have had a stent
implanted. It can be used in patients who suffer a heart attack with "ST segment
elevation" when the doctor thinks the treatment may be beneficial. It can also
be used in patients who do not have such abnormal reading on the ECG, if they
suffer from unstable angina (a severe form of chest pain) or myocardial
infarction without Q waves (a type of heart attack with no ecg graphical signs).
Clopidogrel should be administered as a single daily dose of 75 mg (one tablet)
with or without food. In acute coronary syndrome, associated with aspirin and
treatment generally begins with an initial dose of 300 mg, followed by a daily
dose of 75 mg for at least four weeks in myocardial infarction with elevation of
the ST segment or 12 months in the presence of syndrome without ST segment
elevation. It is an inhibitor of platelet aggregation: it helps to prevent the
formation of blood clots. The blood coagulates when some special blood cells,
the platelets, aggregate. Clopidogel blocks platelet aggregation by preventing a
substance (ADP) from binding to a special receptor on the platelet surface. This
therefore makes the latter little "sticky", reduces the risk of clot formation
and, consequently, prevents the recurrence of heart attacks or strokes.