Mitral Regurgitation

Question 1

Causes of chronic mitral regurgitation

Answer 1

Marfan’s
Cardiomyopathy
Lupus etc
Rheumatic fever

Question 2

Causes of acute mitral regurgitation

Answer 2

Ischemia of papillary muscles/chordate tendinea

Endocarditis

Question 3

Symptoms of mitral regurgitation

Answer 3

Systolic murmur

Weakness

Question 4

The magnitude of regurgitation with MR is influenced by what 2 things?

Answer 4

HR

SVR

Question 5

What is the primary pathophysiology with MR?

Answer 5

Decreased SV

Question 6

How is MR classified?

Answer 6

By regurgitant fraction of SV

Question 7

What is mild MR

Answer 7

< 30%

Question 8

What is moderate MR?

Answer 8

30-60%

Question 9

What is severe MR?

Answer 9

> 60%

Question 10

What are the secondary compensation mechanisms of MR?

Answer 10

Increased blood volume

LA overload

Question 11

What consequence occurs from MR’s compensatory mechanisms?

Answer 11

Left atrial enlargement eventually can’t accommodate more volume and pulmonary edema develops

Question 12

Explain the difference between chronic and acute MR

Answer 12

With chronic MR the LA has time to dilate and accommodate volume giving long term compensation
With acute MR there is a sudden overload of the LA without time for compensation and pulmonary congestion is likely

Question 13

How does LA overload eventually lead to LV failure?

Answer 13

The volume gets recirculated over repetitive cardiac cycles and eventually the LV has too much volume, becomes compliant, eccentric hypertrophy occurs, and eventually LV failure

Question 14

With MR LA overload leads to LV failure, how does the LV at first compensate, and what shows LV failure

Answer 14

As the volume in the LV increases, it becomes compliant and eccentric hypertrophy occurs to compensate for the additional volume. Eventually compensation fails and the pressure also increases

Question 15

What are V waves?

Answer 15

V waves are an abnormal wave on a PCWP that result from regurgitant flow through the mitral valve

Question 16

What does the sign of a V wave mean?

Answer 16

The size of the V wave correlates to the severity of MR regurg

Question 17

What does a sudden onset of V waves mean?

Answer 17

Acute MR

-may be from ischemia of papillary muscles

Question 18

What are the anesthesia goals for MR and HR?

Answer 18

Modest increase in HR

Question 19

Why is a modest increase in HR best for MR?

Answer 19

SV is rate dependent

Sudden bradycardia causes abrupt LV overload

Question 20

What are the anesthesia goals for preload and MR?

Answer 20

Maintain of increase preload

Question 21

What are the anesthesia goals for SVR and MR?

Answer 21

Decrease SVR

Question 22

Why is is good to decrease SVR with MR?

Answer 22

Less resistance promotes forward flow

Question 23

What are the anesthesia goals for contractility and MR?

Answer 23

Maintain contractility to keep volume moving forward

Question 24

Goals are more manageable with what anesthetic technique?

Answer 24

General

-regional may be tolerated, but anticoagulation may be an issue

Question 25

Induction drugs and MR

Answer 25

Any

Ketamine increases HR which is good, but increases SVR which is bad

Question 26

Muscle relaxant and MR

Answer 26

Any

Pancuronium increases HR which is good

Question 27

Volatile anesthetics and MR

Answer 27

Isoflurane is ideal because it is the strongest vasodilator (good), and has a modest increase in HR (good)
SEVO and DES are good too

Question 28

Monitoring and MR

Answer 28

5 lead to monitor for ischemia

PAC may be useful for titration of vasodilators

Question 29

What information can a PAC help obtain

Answer 29

Adequate preload - which is essential to maintain net forward volume
Failing ventricle benefits from afterload reduction
Over aggressive vasodilation risks preload reduction
Helps find optimal filling pressure

Question 30

Does stenotic or regurgitant valve disease lead to more hemodynamic changes?

Answer 30

Stenotic leads to more hemodynamic changes