Cardiovascular Disease

Question 1

Canadian Cardiovascular Society grading of angina pectoris

Answer 1

Grade I
Ordinary physical activity does not cause angina, such as walking and climbing stairs. Angina with strenuous or rapid or prolonged exertion at work or recreation.

Grade II
Slight limitation of ordinary activity. Angina occurs when walking or climbing stairs rapidly; walking uphill; walking or stair climbing after meals; or in cold, or in wind, or under emotional stress; or only during the few hours after awakening. Walking more than two blocks on level ground and climbing more than one flight of ordinary stairs at a normal pace and in normal conditions.

Grade III
Marked limitation of ordinary physical activity. Angina occurs when walking one or two blocks on the level and climbing one flight of stairs in normal conditions and at normal pace.

Grade IV
Inability to carry on any physical activity without discomfort; anginal syndrome may be present at rest.

Question 2

When to operate on a patient who has suffered a myocardial infarction?

Answer 2

According to the 2014 American College of Cardiology/American Heart Association
(ACC/AHA) guidelines for perioperative cardiac evaluation before noncardiac surgery, no fewer than 60 days should elapse between recent MI and noncardiac surgery. Though significant risk reduction occurs by 60 days post-MI, the
risk of reinfarction remains elevated for up to 1 year after MI. After 6 months, the 5% to 6% incidence of myocardial reinfarction is about 50 times higher than the 0.13% incidence of perioperative MI in patients undergoing similar
operations but in the absence of a prior MI.

Question 3

At what point in the perioperative period do most myocardial reinfarctions occur?

Answer 3

Most perioperative myocardial reinfarctions occur in the first 48 to 72 hours postoperatively.

However, if ischemia is initiated by the stress of surgery, there can be an increased risk of MI for several months after surgery

Question 4

… lead is a useful selection for detecting ST-segment changes characteristic of ischemia of the left ventricle during anesthesia, whereas lead … is the most sensitive for detection of arrhythmias

Answer 4

precordial V5

II

Question 5

Perioperative dexmedetomidine has been
shown to reduce delirium after both cardiac surgery and noncardiac surgery

T or F

Answer 5

T

Question 6

All volatile anesthetics induce ischemic preconditioning to varying degrees and may protect the myocardium from subsequent ischemia

T or F

Answer 6

T

Question 7

Surgery and/ or anesthesia in patients with bifascicular block increases risk of developing third-degree heart block

T or F

Answer 7

F

Surgery and/ or anesthesia in patients with bifascicular block DOES NOT increase risk of developing third-degree heart block

Question 8

Causes of increased pulmonary vascular resistance during the perioperative period

Answer 8

hypoxemia, hypercapnia, acidosis, hypothermia, hypervolemia, and insufficient anesthesia and analgesia

Question 9

All surgery patients with vascular disease should be considered for prophylactic … therapy.

Perioperative administration of … reduces the
perioperative mortality rate 50% to 90%.

… should be started as soon as patients are identified as needing surgery

Answer 9

β-blocker and statin

β-blockers

β-blocking drugs

Question 10

Describe the four basic components of a cardiopulmonary bypass circuit

Answer 10

venous reservoir, pump, heat exchanger, and oxygenator

Question 11

Describe the pH Stat Versus Alpha Stat Management During CPB

Answer 11

1) Alpha Stat
Description: arterial blood gas (ABG) is temperature uncorrected (i.e., ABG measured at 37°, regardless of body temperature)

Advantages:
- Easier to implement;
- Physiologic response to hypothermia is maintained;
- Cerebral autoregulation is maintained

Disadvantages:
- Can cause cerebral vasoconstriction because of alkalemia;
- Leftward shift of oxyhemoglobin dissociation
curve can reduce supply to vulnerable tissues

2) pH Stat
Description: ABG is temperature-corrected to the patient’s temperature. CO2 solubility is increased at lower temperatures, leading to a decline in Pco2. To maintain normal pH, carbon dioxide is added to the circuit. Cerebral autoregulation is uncoupled.

Advantages:
- Cerebrovascular vasodilatation and improved
cerebral blood flow, particularly during deep hypothermic circulatory arrest;
- Improved global and regional cooling.

Disadvantages:
- Potential for increased embolic burden to
cerebrovascular system.