Chapter 25: Cardiovascular Disease Flashcards
Incidence of myocardial reinfarction periop
2-6 months post-op: up to 37%.
>6 months post-op: 5-6%.
Most reinfarctions occur 48-72hrs post-op.
Highest risk in thoracic and upper abdominal procedures lasting >3 hours.
Factors that don’t predispose to reinfarction
1) site of previous MI
2) history of prior CABG
3) type/site of surgery if short case (<3 hours)
4) type of anesthesia
Preferred peri-operative beta-blocker for cardiac risk reduction
Atenolol or bisoprolol (B1 selective), but no evidence for switching b-blockers. Metoprolol shown less effective, but also B1 selective and can be used.
Start b-blocker pre-op?
In non-cardiac surgery, evidence shows an association of beta-blockers with increased all-cause mortality and stroke rate (Cochrane 2018.
In cardiac surgery, they can substantially reduce the high burden of supraventricular and ventricular arrhythmias in the aftermath of surgery. Their influence on mortality, AMI, stroke, congestive heart failure, hypotension and bradycardia in this setting remains unclear.
What was the POISE trial?
Perioperative Ischemic Evaluation (POISE), found that prophylactic b-blocker use initiated on the morning of a noncardiac surgical procedure was
associated with a higher risk for bradycardia, stroke, and mortality.
Start clonidine pre-op?
POISE-2 trial: administration of low-dose clonidine in patients undergoing noncardiac surgery did not reduce the rate of the composite outcome of death or nonfatal myocardial infarction; it did, however, increase the risk of clinically important hypotension and nonfatal cardiac arrest.
Start statin pre-op?
Perioperative statins appear to be protective against postoperative myocardial infarction in non-cardiac surgery and associated with higher AKI in cardiac surgery. Controversial and no strong evidence.
Level B evidence that starting statin in vascular surgery patients is reasonable.
Artery and Myocardial region associated with II, III and aVF.
RCA; RA, SA node, AV node, RV
Artery and Myocardial region associated with V3-V5
LAD; Anterolateral aspects of LV
Artery and Myocardial region associated with I and aVL
LCX; Posterolateral aspects of LV
RCRI criteria
Cr>2.0, CHF, IDDM, High risk surgery (intrathoracic, intraabdominal, or suprainguinal vascular), Prior CVA/TIA, CAD
0 or 1 = low risk, >=2 = elevated risk
Who should get a pre-op 12 lead ECG?
Known coronary dz or other structural heart dz, except for low risk surgery.
May be considered in asymptomatic patients, except for low risk surgery.
Who should get a pre-op LV function analysis (e.g. echo)?
Dyspnea of unknown origin, HF with worsening dyspnea or other clinical worsening.
May consider reassessment of known LV dysfunction if no assessment within a year.
Do you need exercise stress testing for patients with elevated risk of MACE, but moderate to excellent functional capacity?
No, reasonable to forgo and proceed to surgery with METS >4 (definitely for >10)
Do you need exercise stress testing for patients with elevated risk of MACE, but poor functional capacity?
Yes, if it will change management.
What should you look for on myocardial perfusion imaging to predict MACE?
Reversible perfusion defects predict events. Fixed defects do not.
When can a patient have elective noncardiac surgery following PCI with stent?
BMS - 30 days post-implant
DES - 6 months post-implant optimally
(Per 2016 ACC/AHA)
Can you consider elective noncardiac surgery at 4 months post-DES?
Yes, you can consider at 3 months, and if possible continue ASA, and restart P2Y12 inhibitor as soon as possible post-op. (If the risk of further delay of surgery is greater than the expected risks of stent thrombosis.)
Per 2016 ACC/AHA
Which volatile anesthetic is associated with coronary steal? which is associated with tachycardia and hypertension?
Isoflurane
Desflurane (sympathetic stimulation with rapid increases)
NMBs that evoke histamine release and decrease SBP
mivacurium and atracurium
Rapid increases in desflurane may cause:
tachycardia, HTN, pHTN and bronchospasm
Avoid in mitral stenosis
Tachycardia, AF w/ RVR
Decreased SVR
Hypoxemia/Hypoventilation (increased PVR)
Avoid in mitral regurg
Bradycardia (goal 80-100)
Increased afterload
Myocardial depression
What waveform is seen in mitral regurg?
PA wedge waveform as a large v wave and a rapid y descent
B1 selective B-blockers
Bisoprolol, Esmolol, Atenolol, Metoprolol
Nonselective B-blockers
Timolol, Nadolol, Sotalol, Propranolol
Aortic stenosis murmur
systolic murmur in right 2nd intercostal space (radiates to right carotid)
Critical aortic stenosis pressure gradient and valve area
Hemodynamically significant aortic stenosis pressure gradient and valve area
<1.2 cm2
Avoid in aortic stenosis
Bradycardia
Atrial fibrillation
Hypotension (need to maintain afterload)
Why have a defibrillator nearby for aortic stenosis?
Compressions are unlikely to generate adequate stroke volume across stenosed valve
Should you continue a patient’s statin or b-blocker perioperatively?
yes and yes (level B evidence)
- ACC/AHA 2014
