Download Presentation

Pre-hospital thrombolysis is associated with
mortality reduction and prognosis improvement in
patients with ST-elevation myocardial infarction
Class n.7
[email protected]
1
Introdução à Medicina
2008/2009
Introduction
Acute myocardial infarction (AMI)
• Destruction of myocardial tissue resulting from inadequate supply of oxygen
to the heart muscle.
LCA – left coronary artery;
RCA – right coronary artery;
1 – Occlusion;
2 – Myocardial infarction.
2
And how can this happen?
1.http://www.emedicine.com/emerg/TOPIC327.HTM
Atherosclerosis
(formation of plaques in blood vessels)
Narrowing of the lumen
Artery Stenosis
Thrombi formation
3
2.http://www.emedicine.com/emerg/TOPIC831.HTM
Thrombus
• Formed usually by platelets, fibrin, red
and white blood cells and are attached to
a plate or in alignment with it.
• Release thromboxane A2, serotonin and
thrombin, all vasoconstrictor substances
that lead to a vicious cycle of recurring
occlusion.
4
2.http://www.emedicine.com/emerg/TOPIC831.HTM
Thrombosis of coronary arteries
Rupture of plaques or fragmentation, followed by subsequent release of the
material.
 Formation of a "buffer" platelet;
 Liberation from the material of the plate, thromboplastin
which will activate the clotting;
 Obstruction of the vascular lumen components of the plate;
5
AMI
2.http://www.emedicine.com/emerg/TOPIC831.HTM
AMI Diagnosis
• Signs and symptoms;
• Biochemical data;
How should we
react?
• ECG alterations (ST-elevation).
6
http://www.emedicine.com/emerg/TOPIC327.HTM
Identify the signals
Activate the National Institute of Medical
Emergencies (112)
Reduction of injuries and consequent
harm to the patient
“Time is myocardium”
7
Signs and Symptoms
• Retrosternal discomfort ;
• Discomfort in one or both arms, neck,
the jaw, on the back or epigastrium;
• Dyspnea ( breathing difficulty);
• Diaphoresis (excessive sweating), nausea
and vomiting.
8
1.http://www.emedicine.com/emerg/TOPIC327.HTM
ECG
An electrocardiogram is a noninvasive transthoracic graphic produced by an
electrocardiograph, which records the electrical activity of the heart over
time.
9
Normal ECG
Schematic representation of normal
ECG
3.http://www.ecglibrary.com/
ECG with ST-elevation
The typical ST segment duration is usually around 0.08 sec (80 ms). An
elevation of >1mm and longer than 80 milliseconds may indicate myocardial
infarction.
Schematic ECG with
St-elevation
10
ECG showing ST-segment elevation (orange) and
reciprocal changes (blue) in the inferior leads.
3.http://www.ecglibrary.com/
Treatment
• In acute myocardial infarction with ST-segment elevation the best treatment is
reperfusion in the first 2 hours after the onset of symptoms.
Reperfusion
11
Pharmacologic
al
Mechanical
Thrombolytic
therapy
Angioplasty
4. ACC/AHA Guidelines for the
management of patients with STelevation myocardial infarction.
5. JAMA, 287(15): 1943–1951.
Thrombolytic therapy
• Treatment given intravenously allowing the opening of the coronary artery;
• The thrombolysis consists in the dissolution of the fibrin clot that blocks thrombus
included in the coronary artery.
12
4. ACC/AHA Guidelines for the
management of patients with ST-elevation
myocardial infarction.
5. JAMA, 287(15): 1943–1951.
American College of Cardiology and
American Heart Association
Recommendations (Guidelines)
• ACC and AHA recognize that “most benefit in seen in those treated soonest with
thrombolytics after the onset of symptoms.”
• Their analysis of published studies “has shown significant reduction (range 15 to 20%) in
early mortality with pre-hospital treatment.”
• ACC and AHA think that “must be interpreted with caution” because in the analyzed studies
“time to treatment was not randomized”. However, they consider results “as an additional
indirect support for the initiation of fibrinolytic treatment”.
• ´ACC and AHA also indicate that administration of thrombolytics is contraindicated in
certain cases (Aortic dissection, knowing bleeding disorder, ischemic stroke, central nervous
system damage or neoplasm,…)
13
4. ACC/AHA Guidelines for the management of patients with
ST-elevation myocardial infarction
Background
14
•
Time to thrombolysis remains a key modifiable determinant of mortality in ST-elevation
myocardial infarction. Despite many years of medical advances, the time from symptom
onset to thrombolysis has remained at large unchanged, with a median of 2.5–3 h.6
•
A pre-hospital treatment strategy when compared with in-hospital thrombolysis may
reduce time to thrombolysis with a subsequent reduce of in-hospital mortality and
complications. 1-year mortality seems also to be reduced.6,7,8
Time till thrombolysis is
a key factor in the
reduction of injuries and
harm to the patient.
6. European Heart Journal. 2006 May; 27(10):1146-1152;
7. Circulation. 2004 Oct 5; 110(14):1909-15;
8. European Heart Journal. 2008 October; [Epub ahead of print].
Problem
• There are sparse and scatter data on the impact of pre-hospital thrombolysis (PHT) in
real-life patients with ST-elevation myocardial infarction. Sometimes this data is even
contradictory.9,10 Therefore it is difficult to evaluate the impact of PHT and how it
reduces time to thrombolysis, complications and mortality.
• In response to this problem, we will try to reunite the able information about this
problematic and use it to find if PHT and the consequent reduction of till thrombolysis
can really reduce complications and mortality.
15
9. Emergency Medicine Journal 2004; 21:625–629;
10. Heart 2002;88:583–586.
Study Aim and Question
PHT
PHT
Develop a study that could lead us to an answer the question:
16
Is PHT beneficial in terms of morbidity and
mortality on patients with ST-elevation
myocardial infarction?
Objectives
 Determine if pre-hospital thrombolysis is associated with reduction in early
and late (1 year) cardiovascular mortality in patients with ST elevation
myocardial infarction.
 Evaluate if pre-hospital trombolysis is associated with prognosis
improvement such as: hospital stay, left ventricular ejection fraction,
reenfartion rates, reenfartion readmission rates.
 Determine if pre-hospital thrombolysis performed by non medical teams is
associated with and increase in complication rates.
17
Methods
• Systematic review of prospective cohort studies and posterior metanalysis.
• If possible, we will also include clinical trials about PHT. Studies will be chosen
according to the following criteria of inclusion and exclusion:
18
Inclusion
Exclusion
1. Study type: Clinical trials and
Cohort studies only;
2. Studies Aim: Studies that evaluate
the efficacy of PHT;
3. Thrombolytic type: New generation
thrombolytics;
4. Follow-ups till 1 year.
1. Study language: Non-english studies;
2. Thrombolytic type: 1st generation
thrombolytics.
Query (sketch)
• Databases:
• Keywords:
Medline;
2. Scopus;
3. ISI Web of Knowledge.
1.
1.
2.
3.
4.
5.
19
Acute Myocardial Infarction
(MeSH);
Pre-hospital thrombolysis (MeSH);
Alteplase, Reteplase OR Tecneplase;
Treatment delay;
Mortality (MeSH).
References
20
1.
Drew Evan Fenton et al. Myocardial Infarction [Internet]. New York: eMedicine Clinical Knowledge Base;
[updated Oct 10, 2008].Available from: http://www.emedicine.com/emerg/TOPIC327.HTM
2.
José G Cabañas et al. Thrombolytic Therapy [Internet]. New York: eMedicine Clinical Knowledge Base; [updated
Jun 22, 2006].Available from: http://www.emedicine.com/emerg/TOPIC831.HTM
3.
Dean Jenkins, Stephen Gerred. ECG Library [internet] [updated Oct 12, 2002].
http://www.ecglibrary.com.
4.
American College of Cardiology (ACC) and American Heart Association (AHA) (2004). ACC/AHA Guidelines
for the management of patients with ST-elevation myocardial infarction. Report of the ACC/AHA Task Force on
Practice Guidelines.
5.
Aversano T, et al. Thrombolytic therapy vs. primary percutaneous coronary intervention for myocardial infarction
in patients presenting to hospitals without on-site cardiac surgery. JAMA 2002 April 7; 287(15): 1943–1951.
Available from
References
21
6.
Erik Björklund, Ulf Stenestrand, Johan Lindbäck, et al. Pre-hospital thrombolysis delivered by
paramedics is associated with reduced time delay and mortality in ambulance-transported real-life
patients with ST-elevation myocardial infarction. European Heart Journal 2006 May; 27(10):114652.
7.
Danchin N, Blanchard D, Steg PG, et al. Impact of pre-hospital thrombolysis for acute myocardial
infarction on 1-year outcome: results from the French Nationwide USIC 2000 Registry.
Circulation 2004 Oct 5;110(14):1909-15.
8.
Danchin N, Durand E, Blanchard D. Pre-hospital thrombolysis in perspective. Overview of current
guidelines and data from trials and registries on the best perfusion approach for acute MI with STelevation. European Heart Journal 2008 Oct 23. [Epub ahead of print]
References
9.
S Goodacre, A-M Kelly, D Kerr. Potential impact of interventions to reduce times to thrombolysis.
Emergency Medicine Journal 2004 Sep;21(5):625-9.
10. J Wilkinson, K Foo, N Sekhri, J Cooper, et al. Interaction between arrival time and thrombolytic
treatment in determining early outcome of acute myocardial infarction. Heart 2002
Dec;88(6):583-6.
22