Cardio Flashcards
What is the pathophysiology of AMI
Inadequate perfusion to meet myocardial oxygen demand causing cell necrosis and death. (Myocardial oxygen demand determines by HR, afterload, contractility and wall tension)
More commonly caused by UNSTABLE fibro-fatty plaques (lipid rich core with fibromuscular cap) can spontaneously rupture and result in cascade of inflammatory event, thrombus formation and platelet aggregation causing acute obstruction.
Alternatively STABLE fibrous plaques that don’t cause symptoms until they are occluding the vessel
What are some non traditional risk factors for ACS
CKD ( in grace score)
Autoimmune (SLE, RA, etc)
Field radiation or chemo
Female specific - PET, GDM, Preterm delivery
HIV
Antipsychotics and hx of mental health
Indigenous
Compliance and ability to follow up for otpt investigations
What are some risk factors for an atypical presentation of ACS
Women
Non caucasian
DM
Elderly (especially >85 would present with faitgue, dysponea, confusion or syncope)
Dementia
Intellectual disability
Risk of delay in diagnosis with worse outcomes/prognosis and increased risk of complications
HFA risk tool
Combination of hx, exam and troponin and ECG changes
Findings to predict 30-day MACE for pts
High sensitivity >78% (NPV 98%) pts but low specificity (~10%) (PPV 23)
Advantage - easy tool for use in various different centers and accessible to inexperienced and junior doctors
Disadvantages - poorly defined intermediate risk group. Given poor specificity, large number of pts will be categoriesed to high risk
Why are Risk Assessment tools for ACS recommended?
Allows quantification of risk for 30-day major adverse cardiac event (MACE)
Reduce misdiagnosis and inappropriate discharge from 2-8% to less than 1%
Increase absolute rates of early discharge for low-risk pts by up to 20-40%
What is the TIMI score
Estimates mortality for pts with unstable angina and NSTEMIs
Used in ED to help risk stratisfy pts for potential otpt management with presumed ischemic chest pain within the nest 1 -2 weeks
Originally derived from pts with known UA or NSTEMI
5% risk of adverse outcome within 14 days for score of 0, so HEART score better for risk stratifying low risk pts
THREAAT
T - Troponin
H - History of CAD >50% stenosis
R - Risk factors >2
E - ECG ST 0.5mm changes
A - Aspirin within 7 days
A - Age over 65
T - Two episodes of CP within 24hrs
What is the ADAPT protocol
Accelerated diagnostic protocol using TIMI score with 0 and 2hr ECGs and troponins to identify who can safely be discharged home for otpt followup
Low risk 0-0.3% risk MACE in 30days
Intermediate (normal trop, ecg and TIMI 1) 0.8%
High risk 15.3%
Included pts >18 with at least 5 minutes of chest pain
Has a sensitivity of 99.7% for identifying low risk pts
False negative of 3% if TIMI 1
Modified ADAPT (highly sensitive troponin) uses TIMI 0 or 1 for low risk
Recommended by National Heart Foundation Australia and Cardiac Society of Australia and New Zealand when sensitive or highly sensitive troponins available
What is the HEART score
Risk stratification with UNDIFFERENTIATED chest pain in pts >/= 21yrs for risk of MACE at 6 weeks
Outperforms TIMI and GRACE in identifying low-risk pts
Needs experience taking detailed chest pain history and interpreting ECGs
Not to be used in new ST elevation or clinically unstable pts
Combined with 0 and 3hr troponins to develop HEART Pathway
What is EDACS?
Clinical tool to identify WHO can have a 0 and 2hr ECG troponin to investigate for ACS (instead of 0 and 6hr).
EDACS-ADP combines EDACS score with trop and ECG to determine who can safely be discharged
Sensitivity 99-100% for correctly identifying low risk pt
Able to identify more low risk pts then
ADAPT ADP and modified HEART
Provided no guidance on what to do for not pts not classified as low risk
USE IN
Pts over 18 presenting with normal vital signs and NO ongoing chest pain
What are the 5 types of MI and how are they classified
Defined by pathological, clinal and prognostic factors
Type 1 - spontaneous MI (atherosclerotic plaque rupture, ulceration, erosion or dissection resulting in intraluminal thrombosis)
Type 2 - MI secondary to ischemic imbalance from condition other than CAD eg spasm, tachy/bradyarrhythmia, anemia, hypo or hypertension, hypoxia etc
Type 3 - Death from suspected MI before biomarkers available
Type 4 - MI related to PCI or stent thrombosis
Type 5 - MI related to CABG
What are some cardiac and non cardiac causes of elevated troponin
CARDIAC
- Heart failure
- Myocarditis
- Cardiac contusion
- Cardioversion
- Takotsubo
- Rhabdo
- Angioplasty
NONCARDIAC
- Renal failure
- PE and severe PHTN
- Severe critical illness such as sepsis or resp failure
- Burns >30% TBSA
- Stroke and SAH
- Extreme exertion
When should repeat troponins be taken
When using POC troponin 6-8hrs post
When using sensitive lab assay
- 2hrs if TIMI score 0
- 6hrs if TIMI>0
When using highly sensitive lab assay
- 2hrs if TIMI 0 or 1
- 3hrs if TIMI >1
When can a single troponin be taken
Presenting with pain and symptoms resolving >12hrs prior to testing
Pts with inital highly sensitive trop < limit of detection and symptom onset >3hrs prior to testing
What are some high and low risk features of chest pain
HIGH RISK
- Ongoing or recurrent chest pain despite treatment
- Elevated trop
- New ECG changes (>0.5mm ST depression, transiet >0.5mm ST elevation or new TWI >2mm in 2 or more contigour leads Wellens Syndrome)
- Diaphoresis
- Heamodynamic compromise (SBP<90, cool peripheries, new mitral regurge, Killlip Class >1)
- Sustained VT
- Syncope
- Known LVEF<40%
- Prior AMI
LOW RISK
- Age<40
- Atypical symptoms
- Remain symptom free
- Non known CAD
- Normal trop
- Normal ECG
When should otpt follow up be organized for intermediate risk chest pain
Within 2 weeks
