Valves

Question 1

Drug therapy for valvular disease

Answer 1

1. Digitalis (Digoxin) - Given to increase contractility and slow the ventricular rate in those with a-fib
2. Diuretics - May be given for excess intravascular fluid volume, but resultant hypokalemia can place at risk for digitalis toxicity
3. Prophylactic Antibiotics - Recommended for the protection against the development of sub-acute bacterial endocarditis

Question 2

Tests for valvular heart disease? what will they tell us?

Answer 2

1. Doppler Echo -
   
   • ​valve movement, flow and pressure gradients
2. Cardiac cath
   
   • measure the severity of valvular heart disease
   • valve movement, flow and pressure gradients
3. ABG→decreased PaO₂ and V/Q mismatch

Question 3

Pathophysiology of mitral stenosis

Answer 3

1. Most common in females
2. Primary cause = rheumatic fever (slow development over 20-30 years)
3. Valvular manifestations:
   
   • fusion of mitral valve leaflets at the commisures
   • calcification of annulus an leaflets
4. Senosis with a valve 2 (normal 4-6cm²) need 25 mmHg to generate adequate cardiac output
5. Stenosis over time will lead to
   
   • ​Left atrial enlargement
   • Pulm HTN
   • RV enlargement and RF failure

Question 4

What are some complications associated with Left atrial enlargement?

Answer 4

• Left atrial enlargement - Predisposes to a-fib
• A-fib→stasis and development of thrombi
• Anticoagulants are needed

Question 5

Severe Mitral stenosis can lead to

Answer 5

CHF

Question 6

Mitral Stenosis

Anesthetic Management GOALS

Answer 6

SLOW, TIGHT, and FULL → prevention and treatment of events that decrease CO or cause pulmonary edema

1. Slow HR 50-60:
   
   • Avoid tachycardia or a-fib with RVR (both decreases CO and cases pulmonary edema d/t increased RA pressure)
2. Tight controll of blood volume:
   
   • Tight fluid administration, give blood or colloids.
3. Full:
   
   • manitain preload→avoid marked increases in blood volume from over-transfusion or head-down positions →still need adequate pressures to overcome the stenosed valve.
   • Maintain afterload →Large decreases in SVR will drop preload. More importantly - the compensation for decreased SVR→baroreceptor reflex→increases HR which will generate a LOW CO in this patient! (avoid NTG, and hgh MAC techniques→IAs will drop SVR).
   • ​​​​Manitain full contractility

(also avoid arterial hypoxemia/hypoventilation that may exacerbate PulmHTN→leading to right ventricualr failure)

Question 7

Induction for MITRAL STENOSIS pharmacologic considerations

Answer 7

1. Etomidate is ideal (if you must use propoflol use it with phenylephrine, also give esmolol prior to DVL)
2. Goal = ventricular rate controll!
   
   • USE: ß-blockers, CCB
   • AVOID: tachycardia →decreases left ventricualr filling and increases left atrial pressure! a drop in SV
   • AVOID things that increase HR→ NO KETAMINE, No anticholinergics (glyco or atropine), histamine releasing drugs
   • AVOID things that abruptly decrease SVR→ Better to chose a high opioid techniqe over IAs , Propofol, NTG
   • USE: Phenylephrine (pure vasoconstrictor) and Vasopressin (does NOT effect the pulmonary vasculature) to treat/avoid decreased SVR
3. Possiblly avoid nitrous → it increases pulmonary vascular resistance which may potentiate pulmonary edema
4. Desflurane → not a good choice it decreases SVR and causes increased HR and BP transiently when increased - ISO = slow ∆ abd time for body to adapt

Question 8

Patho of mitral regurgitation

Answer 8

1. Usually d/t rheumatic fever and is almost always associated with mitral stenosis.
2. Causes decreased forward LV Stroke volume and retrograde flow during ventricular contraction - resulting in LA fluid volume overload
3. Can be caused by RA, MI, ruptured chordae tendonae, ischemia to the papillary muscles, congenital disorders

Question 9

Appearance of mitral regurgitation:

1. On PCWP tracing
2. x-Ray
3. EKG

Answer 9

1. Reguritant flow = V wave on PCWP tracing
   
   • (Size of the V wave correlates with the magnitude of regurgitant flow)
2. X-ray shows cardiomegaly
   
   • (eccentric hypertrophy over time to compensate for decreased CO)
3. EKG shows ​Left atrial and left ventricular hypertrophy
   
   • ​​(Atrial = notched broad P wave)

Question 10

Mitral regurgitation anesthetic management GOALS

Answer 10

Fast, Full, Forward

Goal = improve LV forward stroke volume and decrease the regurgitant fraction:

1. Fast HR: (80-100 bpm)
   
   • Avoid sudden decreases in HR - Bradycardia cuases severe LV volume overload and allows more time for blood to flow backwards
2. Full tank: Preload remains the same
   
   • Increase = more regurgitaion
   • Decrease = Less CO (NTG = bad choice)
3. Forward: Decreased/Normal Afterload
   
   • Decreased SVR promotes forward flow
   • Nitropruside → decreases afterload and allows for more effective cardiac pumping
   • Hydralazine (arterial dialator)
   • Regional may be a good choice to decrease SVR
   • Avoid: sudden increases in SVR, which would promote backward flow
4. Maintain contractility -
   
   • low MAC - balanced techniques - high opioids,
   • inotropes

Question 11

Causes of of aortic stenosis

Associated size and pressure?

Answer 11

1. Calcification developed over time (develops around 60-80 years)
2. Bicuspid Aortic Valve instead of a Tricuspid Aortic valve (develops around 30-50 years)
3. Congenital abnormality
4. Rheumatic heart disease or Endocarditis
5. Normal valve area is 2.5-3.5cm². Significant AS is associated with valve area of <1 cm² and a transvalular gradient of >50mmHg.

Question 12

Explain the pathology of angina associated with Aortic stenosis

What is the classic symptom triad with Aortic Stenosis

Answer 12

1. Angina is often present without CAD
2. The specific contributers to angina
   
   • LV concentric hypertrophy increases oxygen requirements
   • Increased myocardial work to overcome stenosis
   • decreased O₂ delivery d/t compression of the subendocardial vessels
3. Classic triad = Angina, Dyspnea on Exertion, Syncope
   
   • (75% who are symptomatic will die w/ in 3 years if they do not have a valve replacement!)

Question 13

Aortic Stenosis anesthetic management GOALS from class

Answer 13

Prevent hypotension and any hemodynamic change that will decrease cardiac output

1. MUST Maintain NSR: Low/normal (60-90)→avoid sudden decreases in HR (worse) AND tachycardia
   
   • BP is HR dependent
2. Maintain Preload→Optimize intervascular fluid volume to maintain venous return and LV filling
3. Maintain Afterload→Avoid sudden decreases in SVR→decreased coronary filling
4. Maintain contractility

Question 14

Induction in a patient with Aortic Stenosis

Method? Drugs?

Answer 14

1. GENERAL ANESTHESIA is preferred over regional (because regional causes sympathectomy and drop in SVR)
2. Good choice is something that DOES NOT decrease SVR
   
   • Etomidate is best
   • High opioid technique if poor LV function
   • Etomidate + Benzos
   • Propofol + Phenylephrine??
3. AVOID: Ketamine - it causes tachycardia

Question 15

Causes of aortic regurgitation

Answer 15

1. Acute:
   
   • Infective endocarditis
   • Dissection of thoracic aortic aneurysm
2. Chronic
   
   • ​​Rheumatic fever
   • Chronic HTN
   • Marfans
   • idiopathic aortic root dilation
   • bicuspid aortic valve

Question 16

Causes and management of Tricuspid Regurgitation

Answer 16

1. Usually due to pulmonary HTN.
2. RV becomes dilated (usually a functional problem and well tolerated)
3. Leads to RV Volume overload
4. GOALS:
   
   1. maintain fluid volume→preload dependent
   2. avoid a drop in venous return (make sure PPV allows for adequate VR)
   3. Avoid increase in PA pressure
      
      • Avoid N₂O
      • increased PA pressure can cause a right to left shunt if the pt has a PFO
5. Tricuspid regurge is common in seasoned atheletes

Question 17

How do we treat a-fib with RVR?

Answer 17

BBs, CCBs, amiodarone, or digoxin.

Question 18

Preop eval

Answer 18

Syncope, fainting, compensation?

Major end organ disease?

Cardiac hypertrophy, increased SNS output for compensation?

How bad is the CV disease?

Question 19

One of the single best questions for many CV assesments

Answer 19

Exercise tolerance

Question 20

Common symptoms of CHF with valve disease

Answer 20

Dyspnea, orthopnea, fatigue

CHF is a common conpanion with valvular disease

Question 21

what is a common arrythmia associated with valvular disease?

Answer 21

Atrial Fibrilation - due to left atrial enlargement

Question 22

What are the sighns and symptoms associated with Left atrial enlargement?

Answer 22

1. dispnea on exertion
2. orthopnea
3. paroxysmal nocturnal dyspnea

Question 23

with mitral stenosis CO is usually maintained by an increase in atrial pressure - what situations cause CO to drop?

Answer 23

1. Stress induced tachycardia
2. A-fib - when there is a loss in atrial contraction

Question 24

Induction of anesthesia for Mitral Regurgitaion

Answer 24

Remember: Fast, Full and Forward - choices should be based on avoiding bradycardia and avoiding an increase in SVR

1. Maintain fast HR:
   
   • Pancuronium = stimulates the ganglion and causes tachycardia
   • Have Atropine ready, maybe give at induction
   • Etomidate = minimal changes in HR, SVR and CO
   • Propofol + Ephedrine??

Question 25

Mirtal Regurgitation Maintinence and of Anesthesia drug considerations

Answer 25

Maint.Determined by the degree of LV dysfunction 1. **Absence of severe LV dysfunction use** Nitrous + volitile 2. **Use a Lower MAC** - VAs attenuate increases in BP and SVR that accompany surgical stimulation 3. **Opioids** → Class = minimizes likelyhood of drug induced myocardial depression (stoelting says to use caution with high doses becasue of the decrease in HR and myocardial depression) 4. **Isoflurane** - decreases SVE and prevents increases in BP d/t surgical stimulation - Sevo and Des do as well, OK choices 5. **SNP, Hydralazine, (NTG???)** intra op to decrease BP - they all decrease afterload

Question 26

Monitor considerations for Mitral Reurgitation **and** Mitral Stenosis.

Answer 26

1. Invasive monitoring depends on the * surgical procedure * extent of phydiologic impairment * presence end organ dysfunction 2. **CVP** (MR used to monitor V-wave) 3. +/- **a-line** 4. +/- **swan** 5. consider **TEE** if undercoing major fluid shift surgeries (MS may require post op intubation d/t CHF/pulmonary edema - need time to equilibrate)

Question 27

Explain why Normal Sinus Rhythm **MUST** be maintainded in Aortic Stenosis

Answer 27

**HR determines 3 things** 1. **Time for ventricualr filling** * (increased HR = decreased LV filling = decreased CO) 2. **Volume of ejected SV** 3. **Coronary Profusion**→coronaries fill in diastole * (increased HR = decreased coronary blood flow→ ischemia and further LV deterioration) They are **reliant on atrial kick** to have adequate LVEDV * a junctional rhythm or a-fib = **dramatic** decrease in **SV and BP** * Decreased BP = Decreased coronary blood flow = **Ischemia** * ​Hypotension should be treated with **Phenylephrine - b/c it WILL NOT increase HR** AS requires **aggressive treatment of hypotension** to prevent cardiogenic shock → * it is hard to get a BP back because **the force required to overcome the stenotic valve** is too high and adequate SV cannot be attained. For this same reason **CPR is ineffective** in these patients

Question 28

Maintinence of anesthesia in a patient with Aortic Stenosis (key points, drugs and likely complications)

Answer 28

1. _Anestheisa maintained_ with **N₂O + opioids** or if they have significant LV dysfunction a **High Opioid** **Technique** 2. _NMB - w/o CV side effects (_**Roc, Vec, Cis-atra**) * **Bad Choice** = Pancuronium - stimualtes Ganglion and increases HR 3. **Hypotension:** treat with an alpha agonist - **Phenylephrine** (it DOES NOT increase HR) 4. Treat _Junctional Rhythm/Bradicardia_ (**Glycopyrolate, Atropine, Esmolol**) →BP is HR dependent 5. SVT - treat promptly with **cardioversion** 6. Aortic Senosis has a _propensity to develop ventricualar arrythmias_- ALWAYS have **Lidocaine, Amioderone** and a **Defibrilator** Availible

Question 29

Intraoperative monitoring for aortic stenosis MUST consist of this

Answer 29

5 lead EKG that is capable of detecting myocardial ischemia

Question 30

Explain the basis of the valvular disease that has the highest perioperative risk

Answer 30

1. **Aortic stenosis** has the highest risk of intraoperative cardiac complications, increased **mortality** and increased risk of perioperative **myocardial infarction** 2. The risk for myocardial ischemia in aortic stenosis is **INDEPENDENT** of their assoiated risk attributed to CAD

Question 31

The **magnitude** of aortic regurgitation depends on what two things?

Answer 31

1. **_Time_** → determined by HR → **increase HR** = decreased time for regurgitant flow 2. **_Pressure gradient_** across the aortic valve → **peripheral vasodilation** will decrease the pressure gradient and facilitat forward flow

Question 32

Explain the peripheral signs of **hyperdynamic circulation**. Where is it evident?

Answer 32

1. Widened pulse pressure 2. Decreased Diasotolic BP 3. Bounding pusles (evident in disease processes such as aortic regurgitation, liver failure)

Question 33

Aortic Regurgitation Anesthetic Management **GOALS**

Answer 33

Goal: maintain forward LV stroke volume 1. **High**/normal **HR→ 80-100 bpm** * **​​**High HR = less regurgitant volume (decreased diasotlic time where refurgitation can occur) * If HR falls below 80 **→** volume overload and LV failure * Have **Robinul** (glyco) and **atropine** on hand 2. Maintain Preload 3. **Decreased**/normal **Afterload****→** * ​​**AVOID** sudden **increases** in SVR→it will precipitate LV failure * Use of a vasodialator to decrease afterload (SNP, hydralazine, nifedipine) 4. **Maintain contractility** → delicate balance * minimize drug induced myocardial depression * lower MAC, use of opioids or high opioid technique (IF LV failure develops tx with **vasodialator** to reduce afterlaod and **inotropes** to increse contractility **→** ie **dobutamine** + **SNP**)

Question 34

Aortic regurgitation **INDUCTION** anesthetic management.

Answer 34

**Goal**: Avoid decreases in HR below 80, maintain forward LV stroke voume. 1. DOC is usually **Etomidate** 2. Choose a NMB that does not decrease HR * **Roc, Vec, Cis-Atricurium** * **Pancuronium** - stimulates ganglion = increases HR 3. Have **atropine** and **glyco** **READY**! (treat brady promptly) 4.

Question 35

Aortic Regurgitation consiterations for **Maintinence** of Anesthesia

Answer 35

1. **In the absence of LV dysfunction**: * N₂O + volitile anesthetic * Ususally Iso(minimal cardiac depression, CO maintained, preservation of baroreceptor reflex * Des and Sevo ok as well * N₂O + Opioids may unmask myocardial dysfunctction 2. **With significant LV dysfunction:** * High opioid technique **BUT** there is a risk for **bradycardia** - treat promptly with **atropine**! 3. If **hypotension** occurs DOC is **Ephedrine** - increases HR 4. Mantain volume status, **propmt replacemen**t of blood loss to maintain LV SV 5. Treat high SBP with **SNP**