IHD Therapeutics Lecture 2 Flashcards
when a vulnerable atherosclerotic plaque ruptures, what 2 main things happen?
- activation of coagulation cascade
2. platelet adhesion, activation and aggregation
following plaque rupture and the activation of the coagulation cascade and platelet aggregation, what is formed?
a fibrin and platelet clot that occludes the coronary artery and could lead to myocardial infarction
define acute coronary syndromes
a spectrum of conditions resulting in myocardial ischemia after an acute thrombus causes a reduction in blood flow
list 3 characteristics of NSTE-ACS
- ST segment not elevated
- partial (platelet rich occlusion of coronary artery)
- can be ustable angina or NSTEMI depending on presence of cardiac biomarkers (similar presentation, but different severity)
List 4 characteristics of a STEMI
- ST elevation on ECG
- positive cardiac biomarkers
- total occlusion of coronary artery involving platelets and thrombin
- requires immediate coronary angiography and reperfusion
if a patient has the following presentation, what ACS would you suspect they may have? Chest pain described as “pressure”, occurs at rest or with minimal exertion, pain in the retrosternal area radiating to arma, neck, jaw, may have diaphoresis, SOB, nausea, abdominal pain, unexplained or new onset SOB on exertion, atypical symptoms like epigastric pain, indigestion, nausea, vomiting, fatique, syncope
either unstable angina or NSTEMI
if a patient presents with the following, what type of ACS would you suspect? Worsening pain/pressure in the chest described as “suffocating, squeezing, aching”, can presnt with less common atypical symptoms or silent unrecognized MI
STEMI
what objective findings suggest unstable angina?
- ST depression
- T wave inversion
- transient or non-specific ECG changes
- no positive biomarkers for cardiac necrosis
what are the objective findings for NSTEMI?
- ST depression
- T wave inversion
- transient or nonspecific ECG changes
- positive biomarkers (troponin elevation)
what are the objective findings for STEMI?
- ST elevation
2. positive troponin
what is the extent of injury for unstable angina?
no necrosis, partial occlusion of coronary artery
what is the extent of injury for NSTEMI?
myocardial injury, partial occlusion or coronary artery
what is the extent of injury in STEMI?
myocardial necrosis and total occlusion of the coronary artery
what are the goals for unstable angina?
prevent total occlusion
symptom control
risk factor modification
what are the goals for NSTEMI?
prevent total occlusion limit infarct site control symptoms risk factor modification reduce chest pain
what are the goals for STEMI?
- restore blood flow to the infarcted artery
- prevent complications (arrhythmias, death, thrombosis, bleeding)
- risk factor modification
- reduce pain
- restore normal ECG
why are women not as quickly diagnosed with ACS?
they are more likely to present with “atypical” symptoms and ECG changes are often not as clear in women
what is the preferred reperfusion technique?
PCI
for a STEMI how much time do you have from first medical contact (FMC) to PCI?
<120 minutes
when is fibrinolytic therapy indicated for STEMI?
if patient cant get PCI <120min
how long do you have from first medical contact to needle time for fibrinolysis?
30 min
if fibrinolysis is successful, patient needs to go for a PCI within ____(time) and if it fails, the patient needs to go for PCI within ____timeframe
24 hours; IMMEDIATELY
for treatment of NSTE-ACS, what 2 scores are used to determine patient risk and guide therapy?
- TIMI score
2. GRACE score
what is the goal time from FMC to procedure if the patient is diagnosed with STEMI in a PCI center?
90 min or less
what drugs should be used during the PCI prcedure?
anticoagulants like heparin, bivalrudin, or enoxaparin
what drusg should be avoided during PCI?
- routine use of GP 2b/3a inhibitors
2. IC lytics or IC adenosine
what is the default access site for PCI?
radial access
what are 7 complications of PCI?
- bleeding
- re-stensosis
- interventional complications like the dissection or rupture of the artery
- stent thrombosis
- contrast induced nephropathy
- arrhythmias
- mechanical complications like mitral regurgitation
how can contrast induced nephropathy be reduced?
IV fluids and hydration
what is the acronym for the adjunct treatment of STEMI (adjunct to revasularization)
M-Morphine O-oxygen N-nitroglycerin A-ASA B-beta blocker
the canadian CV society recommends against O2 supplementation in patinets with O2 saturation of __% or greater
90
why is routine O2 supplementation not given for STEMI care unless O2 saturation is less than 90%?
O2 supplementation may result in anxiety, impaired communication and has no benefit if the patient is not hypoxic
why does the Canadian CV society advise against routine use of morphine for pain in STEMI patients?
- may mask pain that would indicate failed treatment
2. Inhibits gastric emptying which may cause vomiting (may vomit up oral antiplatelet therapy)
what is the infusion rate for nitroglycerin in hospital as adjunct to STEMI treatment?
10mcg/min and titrated to pain relief
in what situations should nitroglycerin not be given?
- SBP <90
- severe bradycardia (<50bpm)
- tachycardia (>100bpm)
- suspected RV infarction
- patients who have taken a PDE5 inhibitor
why is nitroglycerin C/i with PDE5 inhibitors?
causes life threatening hypotension
must wait ___hrs after sildenafil and vardenafil to give nitroglycerin
24
must wait ___hrs after tradalafil to give nitroglycerin
48
what is the MOA of ASA?
irreversible COX-1 inhibitor at low doses. Blocks the formation of thromboxane A2 and thromboxane platelet activation
what is the typical loading dose given to asa naive patients?
160-325mg
what formulation of ASA should be avoided as a loading dose? Why?
enteric coated bc of delayed and reduced absorption
what is the typical dose of ASA given to all patients?
81mg daily indefinitely (whether they had PCI or not)
ASA reduces the risk of death or MI by ___% compared to no antiplatelet therapy
50
which PGY12-i can be used for STEMI PCI?
clop, tica, prasu
which PGY12-i can be used for STEMI fibrinolysis?
clopidogrel
which PGY12-i can be used for NSTE-ACS PCI?
Clop, tica, prasu
which PGY12-i can be used for NSTE-ACS medical management?
clop and tica
ticagrelor dose fro DAPT
90mg BID
prasugrel dose for DAPT
10mg daily
clopidogrel dose for DAPT
75mg daily
if patients tolerate 1 year of DAPT treatment without risk of major bleeding, what should be done?
extend for up to 3 years
the PLATO study found what when comparing ticagrelor and clopidogrel in ACS for 1 year?
ticagrelor decreased risk of vascular death, MI, stroke, but increased bleeding and SOB
what were the results of the TRITON study that compared prasugrel vs clopidogrel in ACS + PCI for 14.5 months?
prasugrel decreased vascular death, MI, and stroke, but increased major bleeding
in most cases, which PGY12 inhibitors are recommended for DAPT?
ticagrelor and prasugrel over clopidogrel
why is prasugrel not recommended for DAPT in medical management?
due to the findings of the TRILOGY trial which compared prasugrel vs clopidogrel where prasugrel did not decrease vascular death, MI, or stroke
which trials are the basis for using clopidogrel for fibrinolytic DAPT?
CLARITY and TREAT trials
what are some examples of high risk features for thrombotic events?
- diabetes treated with PO hypoglycemics or insulin
- previous stent thrombosis
- smoking
multiple stents or use of biodegradable vascualr scaffold - Left main or proximal LAD stenting
what are some factors associated with increased bleeding risk?
- age >75
- anemia
- body weight <60kg
- regular use of NSAIDS or prednisone
- OAC therapy
what is stent thrombosis?
a life-threatening comlication after stent insertion
what is the most important predictor of stent thrombosis?
premature discontinuation of DAPT
mortality rate is as high as ___% in patients with stent thrombosis
45
what is the MOA of clopidogrel?
irreversible inhibitor of ADP-ediated platelet activation at P2Y12 receptor
is clopidogrel a parent drug or a pro-drug?
pro-drug
what type of prodrug os clopidogrel?
inactive thienpyridine prodrug
what is the loading dose of clopidogrel?
300mg
what PK factor needs to be accounted for when considering clopidogrel?
there are CYP2C19 polymorphisms that impact
what is the MOA of ticagrelor?
reversible P2Y12 inhibitor
what are the c/i for clopidogrel?
- active bleeding
- signoficant liver impairment
- use of repaglinide
what are the c/i of ticagrelor?
- active bleeding
- hx of intracranial hemorrhage
- moderate to severe hepatic impairment
- use of strong CYP3A4 inhibitors
what are the loading and regular doses of ticagrelor?
180mg (loading)
and 90mg BID or 60mg BID (regular)
ticagrelor needs to be used with caution if the patient also has what 2 conditions?
astham, bradycardia
what is the MOA of presugrel?
irreversible thienpyrodine inhibits ADP-mediated platelet activation at the P2Y12 receptor
use of prasugrel is c/i in what situations?
patinet has hx of stroke/transient ischemic attacks
what are the loading and regular doses for prasugrel?
loading: 60mg
regular: 10mg daily