valves 3/20

Question 1

Mitral Stenosis: General Rules

- what is the mantra?

Answer 1

full”-“slow”-“tight
1. Heart Rate: Avoid Tachycardia
-Keep slow for diastolic filling time
- If in afib, control ventricular rate
2. Preload: Maintain
- Keep intravascular volume appropriately full (“maintain”)
- Treat dehydration and hypotension cautiously
- Avoid exacerbation of pre-existing pulmonary hypertension
3. Afterload: Maintain SVR
- To maintain BP with limited CO, these pts normally develop anincrease in SVR
- Afterload reduction does not improve forward flow because the problem with low CO is due to the stenotic mitral valve. o Avoid increases in PVR
4 Contractility: maintain

Question 2

Mitral Regurg:

-what is the mantra?

Answer 2

• full, fast, forward
  
  • full: keep patient volumized
  • fast: keep heart rate maintained (non brady) to increase ejection of blood
  • forward: keep patient SVR lower to allow for blood to be ejected easier

Question 3

mitral valve prolapse (mantra):

Answer 3

-full and forward
full-keep volume up to help push fluids out
forward- keep SVR normal to lower to allow ejection of blood

Question 4

tricuspid regurg: mantra

Answer 4

-maintain

Question 5

aortic regurg

Answer 5

• “full-fast-forward”
• full: keep patient volumized
• fast: maintain heart rate (prevent bradycardia) to eject blood quicker
• forward: decreased BP to allow for emptying

Question 6

aortic stenosis mantra

Answer 6

• “full-slow-tight”
• full: maintain volume
• slow: maintain HR
• tight: maintain BP (decreased SVR causes decreased coronary blood flow; increased SVR causes decreased stroke volume).

Question 7

aortic stenosis:

1. how common an occurance?
2. what are deformities with this valve?
3. what is the pathogenesis for aortic stenosis?

Answer 7

1. most common (5 out of 10,000)
2. Most valves are tricuspid; 1-2% of population have bicuspid valve
3. inflammatory process from mechanical stress causes lipid accumulation>this causes macrophages to infiltrate> they become “foam” cells which stick to valves and become calcified?

Question 8

aortic stenosis: (cont).

1. what is the end result of aortic stenosis
2. what happens to ventricle?
3. what are ventricular dysfunctions that occur?
4. what does the ventricle rely on to maintain stroke volume?

Answer 8

1. obstruction of outflow from LV to aorta causes»decreased C.O. and BP;
2. Left ventricular pressure increases to maintain forward flow»causes concentric LV hypertrophy; which causes decreased compliance and causes imbalance between myocardial supply and demand
3. diastolic (filling) dysfunction or systolic (contractility) dysfunction
4. reley on atrial kick d/t ventricular stiffness.

Question 9

aortic stenosis (3)
what are characteristics of AS:
1. what painful condition is associated with it? why?
2. what happens to LV
3. what does the LV reley on? how much does it provide?

Answer 9

1. angina occurs due to increased myocardial o2 demand from increased muscle mass and decreased o2 supply (d/t compressed coronaries from increased LV systolic pressure)
2. LV eventually fails under increased pressure
3. relies on atrial kick which provides 40% of LVEDV

Question 10

what would the pressure volume loop look like with Aortic Stenosis?

Answer 10

elevated pressure with approximately the same volumes

Question 11

what is the classic triad of aortic stenosis?

Answer 11

1. Angina (Even without coexisting CAD)
   • (Coronary flow can’t meet ↑‘d demands of a big LV)
2. Dyspnea
   • Most common initial symptom
   • Sign of impending LV failure
3. Exertional syncope
   • Helps to rule out other VHDs (specific to AS)
   • inability of the heart to maintain an adequate CO and systemic BP

Question 12

what is the valve size when symptoms start?

Answer 12

1/4 the original size

Question 13

1. where would this murmur be located?

2. what will EKG show?

Answer 13

1. second right intercostal space

2. left ventricular hypertrophy; arrhythmias

Question 14

Aortic Stenosis:

1. Management is determined by what?
2. prognosis is poor if _____?
3. what is patient at risk for and what is the treatment?
4. what are common drugs and diet for AS patients?

Answer 14

1. the symptomatology and degree of failure limitation of activity
2. Poor prognosis if “left untreated once the pt is symptomatic”
3. Antibiotic prophylaxis to prevent infective endocarditis
4. Digoxin, diuretics, ACE Inhibitors, Beta Blockers, Na restriction in diet, etc

Question 15

Aortic Stenosis: medical management

1. what is the newest surgical treatment? who is this procedure for?
2. what is the best procedure for long term?
   a. what is the mortality rate?
   b. how long does it take for ventricle walls to return to normal?
   c. if severe AS, AVR should be done before what?

Answer 15

1. Percutaneous balloon valvuloplasty
   a. Often for nonsurgical candidates
2. Aortic valve replacement best for long term success
   a. Mortality rate is 4%
   b. Takes 8 years after AVR
   c. If severe AS, then AVR should occur before any elective surgery

Question 16

what will the cxr show?

Answer 16

-Chest xray: prominent ascending aorta related to poststenotic dilation

Question 17

anesthesia management for AS:

1. Preservation of ___ is critical? What is ideal?
2. what does excessive bradycardia do?
3. what are 3 ill effects of tachycardia in AS patient:

Answer 17

1. NSR is critical.
   
   • Ideal HR is 50-70 beats per min.
2. Excessive bradycardia causes ↓CO o Prevent Tachycardia
3. increased heart rate:
   a. ↑HR →ischemia
   b. ↑ HR → not enough time for flow across the stenotic aortic valve
   c. ↑ HR → Prevents time for atrial kick

Question 18

1. Treat Arrythmias
2. SVT and afb should be treated how?
3. treat Vfib with…
   4.

Answer 18

1. immediately
2. … synchronized cardioversion
3. …external defibrillation
   * **Must promptly cardiovert vfib because chest compressions are not effective in pushing blood through a stenotic valve

Question 19

what is the formula for stenosis flow vs. diameter?

Answer 19

Q=[(P1-P2)r4] / 8nl

Q= pressure1-pressure2 * 4xradius of vessel divided by 8nl

Question 20

compensatory mechanisms for decreased LVSW and ejection volume (CHF)

Answer 20

Increased SNS activity
o Compensates for hypotension
o Increases HR and contractility

Question 21

ventricular hypertrophy can have either pressure or volume problems: explain

Answer 21

it can be eccentric -in which the ventricle walls thin (stretched out due to high volume) and there is an ejection problem (systolic dysfunction).
or concentric- in which the ventricle walls thicken and there is a filling problem (diastolic dysfunction)

Question 22

1. is myocardail ischemia possible without CAD?

2. what are 2 examples and what happens?

Answer 22

1. Myocardial Ischemia without CAD possible;

2. examples

Question 23

myocardial demand and supply relationship:

Answer 23

-

Question 24

cpr and aortic stenosis:

1. does it work? why?
2. what is the treatment

Answer 24

1. no, the compressions are ineffective against the stenotic valve
2. quick defibrillation

Question 25

aortic stenosis surgery:

1. what is the best induction?
2. what is the best maintainance?

Answer 25

Aortic stenosis surgery:

1. combination of fentanyl, versed and etomidate
2. low gas d/t vasodilatory effects; boluses of fentanyl and NDMR