IHD Flashcards
Prasugrel is contraindicated in 3 occasions?
- Older than 75
- Haemorrhagic stroke - massive increase in risk
- Weight <60kg
Risk factors for IHD? (11)
- HTN
- Smoking
- DM
- Cholesterol
- FH (especially 1st degree relatives <60)
- Obesity
- Lack of exercise
- Erectile dysfunction (often precedes IHD symptoms, marker of endothelial dysfunction)
- Homocysteine
- COX2 or NSAIDs
- OCPs or premature onset of menopause
While at R, what questions / investigations can you ask about adequate risk factor control? (6)
- BP – salt restriction??
- Smoking cessation
- HBA1C
- LDL (<1.8), Cholesterol (<4)
- Weight loss + exercise
- Whether NSAIDs / COX2 are consciously avoided or used liberally
IHD: Complications to ask? (5)
- Heart failure
- Arrhythmias – brady + tachy (Inferior / posterior MI → AV node dysfunction → heart block, VT/VF)
- Embolic events – e.g. stroke from LV thrombus
- Further heart attacks / ACS
- Whether surgery was required for e.g. acute MR or infarc-related VSD
Patient had CABG and has no radial pulse - What does this mean?
•Patient may have had CABG using radial artery
Approach to acute STEMI mx
- Activate the Cathlab
- If unavailable, consider thrombolysis
- Start DAPT – second choice depends on situations
- Planned PCI → tigarelor (180mg) or prasugrel (60mg) loading dose if no CI (prior stroke/TIA, 75yo or older, weight <60kg) – if so Clopidogrel 600mg
- Thrombolysed → clopidogrel 300mg (<75) or 75mg (>75yo)
- Not for thrombolysis → ticagrelor 180mg loading
•Heparin infusion (consider clexane if PCI or thrombolysis not being performed)
Why do you need to Cath the patient who was already thrombolysed?
•Even if thrombolysed, usually PCI required as <60% of patients would have definite opening of infarct-related artery
When would you thrombolyse STEMI patient? (2)
- <12 hours since onset + no absolute contraindications + PCI cannot be performed within recommended time (1A) – usually 2-3 hours
- Symptomatic patient who present after 12 hours (but <24h) when PCI not readily available (2A)
- Tenecteplase or Reteplase is recommended instead of alteplase (2B)
- Regardless, early transfer to PCI centre to decided whether rescue vs. elective PCI is needed.
Approach to UA/NSTEMI?
•DAPT
- For PCI → Ticagrelor 180mg or prasugrel 60mg
- If >75yo, stroke/TIA, <60kg → clopidogrel (300-600mg depending on bleeding risk, thrombocytopaenia…etc) or ticagrelor 180mg
- Not for PCI → Ticagrelor 180mg
•Anticoagulation
- Heparin infusion if PCI planned within 4-48 hours
- Not for PCI → Clexane, at 1mg Kg 12 hourly, dose adjust if CrCl <30 → 1mg/kg every 24 hours
The use of ticagrelor or prasugrel (P2Y12 inhibitor) is based on what trials?
- TRITON-TIMI 38 trial (prasugrel vs. clopidogrel) – HR 0.81 (CV death, non-fatal MI, non-fatal stroke) - But more bleeding events → RF identified are TIA/Stroke, age 75 or above or weight <60kg
- PLATO trial (ticagrelor vs. clopidogrel in ACS) - HR 0.84 at 12 months (death from vascular events, MI or stroke)
- No difference in major bleeding events (11.6% vs 11.2%)
- Associated with higher rate of major bleeding not related to CABG (4.5% VS. 3.8%)
Summary: both ticagrelor & prasugrel are better, but higher risk of bleeding if risk factors present (<75yo, weight <60kg, TIA/stroke).
Is there any other therapy you would consider for those with very high risk of ischaemic event of complication of PCI (e.g. large thrombus burden seen in angiogram)?
- Consider Glycoprotein IIb/IIIa inhibitor (abciximab, tirofiban or epti-fiba-tide) – Grade 2C
- Argument for this is stronger if patient did not have ticagrelor or prasugrel
- However in most patient it is NOT recommended if oral DAPT has been given (1B) so talk to cardiologist
What is your approach to investigating symptomatic patient with IHD? (SOB/CP)
- Assess infarct size, complications and presence of further ischaemia
- TTE: to look for infarct size (RWMA), LV function and complications of infarct (e.g. MR, LV thrombus, infarct related VSD)
- Stress test: inducible ischaemia
- MIBI: inducible ischaemia + viability
- Angiogram
3 indications to consider CABG?
- Diffuse TVD
- Left main disease
- Tight proximal LAD (before 1st diagonal branch)
Non-pharmacological Mx – secondary prevention? (9)
- Cessation of smoking
- Weight loss
- Exercise
- Mediterranean diet (+statin)
- BP control: salt and fluid restriction (+ACEi/BB)
- Diabetes control
- Stress management
- Cardiac rehab
- No sexual intercourse for 1 month following event
Total duration of DAPT following PCI? in following situations
Default
No bleeding risk
High bleeding risk
Duration of single antiplatelet
- Individualised depending on bleeding vs. ischaemic risk
- Regardless of stent type, recommended for at least 6-12 months
- In free of moderate (needing transfusion) or severe bleeding risk → at 12 months review → most advocates additional 18-24 months of DAPT
- Most will favour at least 3 months of DAPT where bleeding risk is very high
- Some will consider as short as 1 month
- Single antiplatelet recommended indefinitely, however, single agent anticoagulation (warfarin, NOACs) would be a suitable alternative if they were already on it for e.g. AF.
Is there any tool that you can use for stratification to decide on the duration of DAPT following PCI in patients with bleeding risk to decide whether to continue further than 12 months of DAPT?
DAPT score – based on DAPT trial (2014)
- Based on traditional ACS risk factors (age, active smoking, DM) and;
- Stent type, whether vein graft was stented
- Prior MI/PCI or MI at presentation, HF, LVEF <30%
Low score (<2) → risk of bleeding > risk of ischaemia ⇒ Harm > benefit with prolonged therapy beyond 12 months
High score (=>2) → risk of ischaemia > risk of bleeding ⇒ Benefit > harm with prolonged DAPT beyond 12 months (18 additional months)
Still need external validation, hence clinical judgement still applies
When would you choose BMS over DES? (3)
• 2nd generation DES preferred then BMS in most cases due to lower need for target vessel revascularization + better safety profile
However, in following occasions BMS is generally more preferred
- Patients who require non-cardiac surgery within four to six weeks of PCI (T&O says if surgery planned within 6-12 months).
- Patients with active bleeding at the time of PCI or those at very high risk of bleeding while taking DAPT.
- Patients unlikely to comply with antiplatelet therapy for at least one month.
Difference between BMS and DES – how are they differ in terms of re-stenosis / thrombosis risk?
BMS
- Increased in-stent restenosis
- Decreased late stent thrombosis
DES
- Decreased in-stent restenosis ⇒ as drugs are anti-neoplastic and prevent migration of SMC into the lumen of vessels (causing restenosis)
- Increased late stent thrombosis
DDx for very early angina following CABG? (5)
- Graft spasm – e.g. mammary artery spasm
- Thrombosis of SVG
- Grafting wrong vessel
- Grafting to wrong area (i.e. proximal to area of stenosis)
- Residual distal disease that is not suitable for grafting – so read the operation notes
Is Aspirin indicated following CABG?
- Yes – shown to prolong graft survival
- Patients with severe diffuse disease are often given DAPT
Would you always consider stenting stable angina patient with single or double vessel disease?
- Optimal medical therapy is just as good as angioplasty in terms of prognosis (except Left main or proximal LAD disease)
- However, angina is better controlled by angioplasty
- Benefit compared with OMT when FFR (fractional flow reserve) during angiogram is suggestive of ischaemia (<0.75 or <0.8)
So to a significant degree, patient preference is important.
What do you mean optimal medical therapy? (6)
- Aspirin + / − clopidogrel (for 1 year post ACS)
- Statin – target LDL 1.8 mmol / L
- ACEI or ARB at maximum tolerated dose
- Beta-blocker – heart rate down to < 70
- Hypertension treated to < 130 / 80
- Exercise 3 times a week at least for > 150 minutes / week
STEMI or NSTEMI in patient already on NOAC
- Difficult Mx problem
- Options are DAPT + NOAC vs. Clopidogrel + NOAC or NOAC only
- Depending on risk of bleeding vs. risk of recurrent ischaemia
Syntax trial?
•PTCA vs. CABG in multivessel and LM CAD
- Same survival
- Increased procedures with PTCA
- Worse outcome in DM with PTCA
- Low Syntax score do equally well
- High Syntax score do much better with CABG
•Syntax score is an assessment of the severity and location of coronary disease used to predict risk of PCI and CABG surgery
Coronary anatomy?
CABG vs PCI?
- Multivessel disease
- Single vessel disease
- Multi-vessel disease – 1st year risk of death, MI, stroke are similar between CABG vs. PCI (but revascularisation rate were higher with PCI)
- Moderate/Complex anatomy, diabetes → CABG (1B, strongly preferred)
- Preserved LV, low complexity anatomy, no diabetes → CABG (2B, weakly prefered), but PCI reasonable
- Proximal LAD with multivessel disease, LV impairment, DM, large area at risk → CABG (2B)
- Discuss in MDT meeting – take into account patient preference (i.e. what is more important to them? lower chance of repeat revascularisation, periprocedural morbidity with CABG, stroke fear – as lower risk of stroke with PCI…etc)
For single vessel disease
- RCA or LCx → PCI (Grade 2C)
- Proximal LAD → PCI (2B)
- But consider CABG if patient prefers to accept higher early morbidity (incl. stroke) and lower rate of revascularisation
Two-vessel disease
•RCA + LCx → reasonable to attempt PCI
Left main disease – CABG vs PCI?
- UTD recommends CABG rather than PCI provided that patient is surgical candidate, especially for those with TVD or high-risk CVD
- Mainly stems from EXCEL trial
- Composite outcome (Death, CVA, MI) similar for PCI vs CABG at 5 years
- However, rate of ischaemia driven revascularisation was higher with PCI
Vein grafts – problem, failure rate at 1 year?
- Most common vein used = Saphenous vein (SVG)
- High failure rates: 10-25% in 12-18 months (mainly stenosis)
- Distal run-off = blood flow in the post-stenotic region of the vessel – adequate distal run-off is important factor in success of vascular grafts
- SVG patency depends on distal runoff of the coronary artery bypassed - the distal runoff (i.e. the flow) is determined by size of native CA – so patency rate is much higher when CA bypassed is LAD, for example
Vein Graft Occlusion risk factors? (5)
- Dyslipidaemia (high TG, chol, low HDL)
- Smoking
- HTN (High MAP)
- Low LVEF
- Small minimum graft diameter
- Hence RF control is of utmost importance in patients with CABG!
Single arterial grafts – patency rate at 10 years?
- LIMA (1st choice due to relative ease) – usually used to anastomosed to LAD
- Patency rate at 10 years = 98% (higher long term survival)
- RIMA - usually to major branch of LCx (patency rate 94%)
- 10 year patency rate = 95% for LIMA, <90% for RIMA, <89% RA
Disadvantage of total arterial vascularisation? (2)
- Sometimes all 3 are used: RIMA, LIMA and RA (i.e. total arterial revascularisation) ⇒ very high long term patency
- Technically demanding – takes longer, operative mortality 0.7%, slightly higher than single vessel
- But if successful, less angina, less need for PCI, AMI compared with SVG
- Mostly: LIMA + (RIMA or RA) – choice depends on the risk of wound infection (e.g. obesity, active smoking, poorly controlled DM, steroids, immunodeficiency)
Things to check Before using RA? (2)
- Important to check for Ulnar flow to prevent loss of hand function
- Expect to see minimal changes in hand function after CABG - some forearm numbness, tingling but NOT motor change, temp, pain sensation. Self limited.
- RA – more prone to spasm as well (hence why sometimes CCBs are used)
- If patient has CKD – try avoid use RA as may be required for dialysis
What is main problem of considering CABG in patients with TIA/Stroke recently? Why does this occur? (2)
↑ risk of perioperative stroke (8.5%) – mainly from cerebral hypoperfusion, TE (particularly Aortic Atherosclerosis)
So what is your approach to preventing Stroke/TE complications for a patient waiting for CABG?
•Identify + manage source of stroke, particularly atherosclerotic aorta + CAS
- Unilateral CAS is ok
- Bilateral significant CAS (50-99%) ⇒ ↑Risk
- Higher risk with ascending aorta artherosclerosis
- RF control with statin, aspirin, anti-arythmics, anti-hypertensives
- Consider carotid artery revascularisation
- Symptomatic, bilateral CAS (80-99%) - 2C
- Asymptomatic unilateral stenosis (70-99%) with total occlusion (100%) on contralateral side
- But NOT of asymptomatic 50-99% unilateral disease (2C)
•Carotid stenting is usually not an option as it will necessitate DAPT
If patient had recent stroke and needs CABG – would you delay it and why? (3)
•If recent stroke – delay CABG** if possible for **several weeks
- To allow for stroke work-up is complete + RF modification has been taken (e.g. CAS management)
- To give sufficient delay to allow for post-stroke recovery of auto-regulatory mechanisms of cerebral vasculature before exposure to peri-operative hypoperfusion
- To allow sufficient time for cerebral remodeling to minimize hemorrhagic transformation
CABG work up?
Septic work up
- CXR, Urine MCS, blood culture, OPG, dental consult
Lungs
- Lung function test – for FEV1 and FVC
- ABG if FEV1 <50% or <1.5L or OSA
Graft
- Vein mapping if SVG being used
- Radial artery USS
Stroke risk
- Carotid USS
- Cardiac CT or MRI (CTA) to assess for ascending aortic calcification
- ECHO – LV function, rule out LV thrombus…etc
Key questions to ask on history - IHD?
P: ACS vs stable disease
Revascularisation vs medical therapy?
indication for revascularisation - symptomatic vs prognostic
Damaged heart? - i.e. suggestive of LV dysfunction
C: complicated by functional MR?
Atypical presentation: e.g. dissection, embolic infarct from (e.g. DVT through PFO), LV thrombus - embolism
Are they attending cardiac rehab?
DDx for persisting angina in patients with multiple angiogram but nothing to stent?
Microvascular CAD - especially more common in diabetic.
