25 Feb Valvular Heart Disease Ppt (Exam 2) Flashcards
What is the incidence of valvular heart disease in the US?
2.5%
This statistic highlights the prevalence of valvular heart disease in the general population.
What types of hemodynamic burdens can valvular heart disease cause?
- Pressure overload
- Volume overload
Which cardiac valve lesions are most frequently encountered?
- Mitral stenosis
- Aortic stenosis
- Mitral regurgitation
- Aortic regurgitation
What is a common co-existing condition with valvular heart disease?
Ischemic heart disease (IHD)
What percentage of patients over 50 years with aortic stenosis have ischemic heart disease?
50%
In pre-operative evaluation, what aspects should be assessed?
- Severity of cardiac disease
- Degree of impaired myocardial contractility
- Presence of associated major organ system disease
What compensatory mechanisms can occur in heart disease?
- Increased sympathetic nervous system activity
- Myocardial hypertrophy
What is the New York Heart Association Functional Classification used for? Describe classes 1 through 4
To evaluate the functional capacity of patients with heart disease
What are some symptoms of heart failure?
- Dyspnea
- Orthopnea
- Easy fatigability
- Basilar rales
- Jugular venous distension (JVD)
- Third heart sound
True or False: A compensatory increase in sympathetic nervous system activity can manifest as anxiety.
True
What causes heart murmurs?
What Mnemonic can be used to determine left vs right side?
- Turbulent blood flow across abnormal valves
- Increased flow across normal valves
RILE
- Right side louder on Inspiration
- Left side louder on Expiration
What does the Mnemonic SCRIPT mean for identifying heart murmurs?
SCRIPT:
- Site
- Character
- Radiation
- Intensity
- Pitch
- Timing
SCRIPT of Aortic Stenosis?
What is the most important characteristic of a murmur?
Timing of the murmur in the cardiac cycle
RILE
- Right side louder on Inspiration
- Left side louder on Expiration
Midsystolic vs holosystolic and diastolic murmurs?
What distinguishes functional (psyiologic) murmurs from pathologic murmurs?
- Functional murmurs are due to physiologic conditions outside the heart
- Pathologic murmurs are due to structural heart disease.
What is a midsystolic murmur?
A murmur that occurs between distinct S1 and S2 heart sounds
A midsystolic murmur can be functional whereas any other murmur is very likely pathologic and requires TTE
What does a systolic murmur indicate?
How does this compare to a holosystolic murmur?
- A systolic murmur indicates Stenosis of the aortic or pulmonic valves
AND/OR - Incompetence of the mitral or tricuspid valves
- A holosystolic murmur merges with S1 and S2
What does a diastolic murmur indicate?
- Stenosis of the mitral or tricuspid valves
AND/OR - Incompetence of the aortic or pulmonic valves
Where can a midsystolic murmur suggestive of aortic stenosis be best heard?
- Right upper sternal border radiating to the carotids (suggests aortic stenosis)
Where can a holosystolic murmur indicative of mitral regurgitation be best heard?
At the apex, radiating to the axilla
Next card is an important picture to memorize for common valvular murmurs.
What are the common auscultatory sites for heart valves?
- Aortic: 2nd ICS RSB
- Pulmonic: 2nd ICS LSB
- Tricuspid: 5th ICS LSB
- Mitral: 5th ICS MCL
What does EKG indicate in valvular heart disease diagnostics?
- Left atrial enlargement (broad/notched P-waves)
- Left or right axis deviation (left and right ventricular hypertrophy)
- Dysrhythmias
- Possible ischemia/previous MI
What does CXR indicate in valvular heart disease diagnostics?
- Cardiomegaly (cardiomegaly can be established if the heart size exceeds 50% of the internal width of the thoracic cage)
- Left mainstem bronchus elevation (D/T enlargement of the LA)
- Valvular calcifications
What is the role of echocardiography in valvular heart disease?
To evaluate cardiac anatomy and function, presence of hypertrophy, cavity dimensions, and valve area.
This is the most sensitive test (definitely>ECG)
What are the two types of heart valve replacements?
What are some distinguishing qualities?
Mechanical valves
* Metal or carbon alloy
* Highly thrombogenic
Bioprosthetic valves
* Porcine or bovine
* Low thrombogenic potential
What is the lifespan of mechanical valves?
20-30 years
Preferred in patients who are young, have a life expectancy of more than 10–15 years, or require long-term anticoagulation therapy for another reason, such as chronic atrial fibrillation.
What is a significant risk associated with mechanical heart valves?
High thrombogenic potential
What is the lifespan of bioprosthetic valves?
10-15 years
Preferred in elderly patients and in those who cannot tolerate anticoagulation.
What is a key consideration for anticoagulation management in surgery for patients with mechanical heart valve replacement(s)?
Discontinuation of warfarin 3-5 days preoperatively (major surgery)
- This temporary discontinuation of anticoagulant therapy puts patients with mechanical heart valves or atrial fibrillation at risk of arterial or venous thromboembolism D/T a rebound hypercoagulable state and to the prothrombotic effects of surgery
Anticoagulation may be continued in patients with prosthetic heart valves who are scheduled for minor surgery in which blood loss is expected to be minimal
What is mitral stenosis primarily associated with? What gender is at higher risk?
Rheumatic heart disease
Females
Patients can be asymptomatic for 20-30years
SCRIPT for mitral stenosis?
Rumbling diastolic murmur at apex, radiates to left axilla
What is the normal mitral valve orifice area?
When do symptoms usually develop?
- 4-6 cm²
- < 2 cm²
Leaflet thickening and calcifications occur primarily due to the chronic stress of turbulent flow through a deformed valve.
- The net result leads to a narrowing at the apex of a funnel-shaped, “fish-mouth” valve.
What are common symptoms of mitral stenosis? (6)
- Dyspnea on exertion
- Orthopnea
- Paroxysmal nocturnal dyspnea
- Pulmonary edema
- Pulmonary HTN
- Atrial fibrillation
What might severe mitral stenosis precipitate?
Pulmonary edema
- Pulmonary venous pressure > plasma oncotic pressure
Left ventricular function is usually preserved.
- When mitral stenosis is severe, any additional stress such as fever or sepsis may precipitate pulmonary edema.
- Over time, changes lead to right-sided heart failure.
What is the typical treatment for mitral stenosis?
- Rate control (β-blockers, calcium channel blockers, digoxin)
- Diuretics (To treat ↑ LA Pressures)
- Anticoagulation (risk of stroke 7-15% per year)
- Surgical correction (Percutaneous valvotomy, Surgical commissurotomy, Valve replacement)
What are the anesthetic goals for patients with mitral stenosis? (3)
Normal heart rate, normal volume, normal afterload
A sudden decrease in SVR may not be tolerated, because the normal response to hypotension—that is, a reflex increase in heart rate—itself decreases cardiac output.
What 2 medications are critical in maintaining BP for an anesthetized patient with mitral stenosis?
- Phenylephrine (Increses SVR/venous return without directly affecting HR like Epi or Ephedrine)
- Vasopression has minimal effect on pulmonary artery pressure.
Avoid pulmonary HTN exacerbation so you don’t end up with RV failure
(Prevent hypoventilation, hypercarbia, hypoxemia)
Why is ketamine a great medication for a patient with mitral stenosis?
Trick question, ketamine is awful for MS D/T because of its propensity to increase HR (SNS effects)
Also avoid avoid histamine releasing NMBs since they can cause tachycardia and hypotension (pancuronium, atracurium)
True or False: Mitral regurgitation is more common than mitral stenosis.
True
- 2% of the US population
Acute MR most often occurs as a sequelae of CAD, in which myocardial ischemia and infarction cause papillary muscle dysfunction and, in some cases, papillary muscle rupture.
SCRIPT for mitral regurgitation?
Holosystolic/pansystolic (heard throughout systole) murmur at apex and radiates to axilla
What can mitral regurgitation be associated with?
- Ischemic heart disease
- Ruptured papillary muscle
What is the pathophysiological consequence of acute mitral regurgitation?
Acute MR most often occurs as a sequelae (because of) of CAD, leading to myocardial ischemia and infarction.
This can cause papillary muscle dysfunction and, in some cases, rupture.
What are the symptoms of mitral regurgitation?
- History of ischemic heart disease, endocarditis, or papillary muscle dysfunction
- Holosystolic murmur at apex
- Radiates to axilla
- Cardiomegaly
- Atrial fibrillation
Diagnosed by:
- EKG (Left atrial and LV hypertrophy, Atrial fibrillation)
- CXR (Cardiomegaly, Left atrial and LV hypertrophy)
- Echocardiogram (Left atrial thrombus)
What is the preferred treatment for symptomatic mitral regurgitation?
Mitral valve repair is preferred over mitral valve replacement.
- Symptomaticpatients should undergo mitral valve surgery even if the ejection fraction is normal
- In asymptomatic patients, surgical intervention is warranted in those with an LV EF of 30% to 60% or an LV end-systolic dimension >40 mm.
Repair restores valve competence and maintains functional aspects of the mitral valve apparatus.
Forsymptomaticpatients, ACEi orβ-blockers (particularly carvedilol) and biventricular pacing have all been shown to decrease functional mitral regurgitation and improve symptoms and exercise tolerance.
What is the goal of anesthetic management in patients with mitral regurgitation?
Improve forward left ventricular stroke volume (SV) and decrease regurgitant fraction.
What are some anesthetic considerations for mitral regurgitation?
Prevention and treatment of decreased CO
Normal to slightly increased HR
- Bradycardia=LV volume overload
Avoid increased SVR
- Vasodilators (nitroprusside)
- An increase in SVR can cause decompensation of the LV.
Afterload reduction with a vasodilator drug such as nitroprusside will improve left ventricular function.
Neuraxial anesthesia
- Thedecrease in systemic vascular resistance caused by regional anesthesia may be beneficial in some patients.
In most patients,cardiac output can be maintained or improved with modest increases in heart rate and modest decreases in systemic vascular resistance.
Why does IV fluid volume need to be maintained with mitral regurgitation?
Maintenance of intravascular fluid volume is very important for maintaining left ventricular volume and cardiac output.
- Full fast and forward “Corndad”
What is the significance of the left atrial volume in mitral regurgitation?
Left atrial volume overload and pulmonary congestion are key consequences of mitral regurgitation.
What is a common echocardiographic finding in mitral regurgitation?
Left atrial thrombus may be present.
Fill in the blank: Mitral regurgitation can lead to _______ due to volume overload.
pulmonary congestion
True or False: In patients with asymptomatic primary mitral regurgitation, surgical intervention is warranted if the left ventricular ejection fraction is less than 30%.
False
Surgical intervention is warranted in asymptomatic patients with an LV ejection fraction of 30% to 60%.
What is the relationship between left ventricular hypertrophy and mitral regurgitation?
LV hypertrophy permits accommodation of the regurgitant volume without a major increase in left atrial pressure.
What is the effect of regional anesthesia on systemic vascular resistance in mitral regurgitation?
The decrease in systemic vascular resistance caused by regional anesthesia may be beneficial in some patients.
What are the characteristics of aortic stenosis?
- Obstruction to ejection of blood into the aorta
- Increased left ventricular pressure
- Concentric left ventricular hypertrophy
- Calcific aortic stenosis (affects as many as 25% of all adults older than age 65, though to varying degrees.)
- Bicuspid aortic valve (BAV is the most common congenital valvular abnormality – 1-2% of the population)
SCRIPT for aortic stenosis?
What are the common symptoms of critical aortic stenosis?
- Angina pectoris (increases risk of MI)
- Syncope (exercise-induced decrease in systemic vascular resistance that remains uncompensated because cardiac output is limited by the stenotic valve)
- Dyspnea on exertion
These symptoms correlate with an average time to death of 5, 3, and 2 years respectively…
- 75% of symptomatic pts die w/in 3 years w/o valve replacement
Increase in myocardial oxygen requirements secondary to concentric left ventricular hypertrophy and the increase in myocardial work necessary to offset the afterload produced by the stenotic valve. In addition,myocardial oxygen delivery is decreased because of compression of subendocardial blood vessels by the increased left ventricular pressure.
What is the normal aortic valve surface area? How about in severe aortic stenosis?
Normal valve area 2.5 - 3.5 cm²
Severe AS valve area < 1cm²
What diagnostic tests are used to evaluate aortic stenosis?
- CXR (Prominent ascending aorta, Aortic valve calcification)
- ECG (LV hypertrophy, ST Depression, T wave inversion)
- Echocardiogram (Tri-leaflet vs bi-leaflet valve, Thickened and calcified, Valve area and transvalvular pressure gradients)
- Exercise stress testing (Poor exercise tolerance &/or abnormal BP with exercise)
What is the treatment for symptomatic aortic stenosis?
- Balloon valvotomy for adolescents/young adults
- Transcatheter aortic valve replacement(TAVR)
Aortic valve replacement (AVR) is necessary to relieve symptoms.
What are the anesthetic considerations for patients with aortic stenosis?
- Maintain normal heart rate and rhythm (Avoid bradycardia or tachycardia)
- Avoid hypotension (Aggressive treatment warranted)
- Optimize intravascular fluid volume (maintain venous return and left ventricular filling)
Unfortunately, CPR is typically not effective because it is essentially impossible to create an adequate stroke volume across a stenotic aortic valve with cardiac compressions done either externally or internally.
What are the anesthetic considerations for aortic stenosis?
- GA > epidural or spinal
- Induction – avoid decreased SVR
- Intravascular fluid volume - maintain normal levels b/c patient is preload dependent
- Hypotension - α-agonists (phenylephrine) to avoid ↑HR
- Junctional rhythm or bradycardia - ephedrine, atropine, or glycopyrrolate (to maintain CO but avoid overreaching and inducing tachycardia)
- Tachycardia - β-blockers (esmolol)
Ketamine may induce tachycardia and should be avoided.
What are the characteristics of aortic valve area in severe aortic stenosis?
Severe AS valve area is less than 1 cm².
What is the average time to death without aortic valve replacement for symptomatic patients?
5 years for angina, 3 years for syncope, and 2 years for dyspnea.
Fill in the blank: The most common congenital valvular abnormality is _______.
bicuspid aortic valve (BAV)
What are the causes of aortic regurgitation? Chronic and Acute
Chronic:
* Endocarditis
* Rheumatic fever
* Bicuspid aortic valve (BAV)
* Anorexigenic drugs (drugs that act on the brain to suppress appetite)
Acute:
* Endocarditis
* Aortic dissection
Substances that tend to suppress appetite orhunger sensationor both – anorexigenic drugs (phentermine, methamphetamine), causes morphology changes to the leaflets and the majority of these lesions produce chronic AR, with slow, insidious LV dilatation.
Aortic regurgitation SCRIPT?
What is the pathophysiology of aortic regurgitation?
- Decreased cardiac output due to regurgitant stroke volume
- Combined left ventricular pressure and volume overload
What are the symptoms of aortic regurgitation?
- Early or mid-diastolic murmur at the left sternal border
- Hyperdynamic circulation
- Widened pulse pressure
- Decreased diastolic blood pressure
What determines the magnitude of Aortic Regurgitation?
- Time available for regurgitant flow (HR)
- Pressure gradient across the aortic valve (SVR)
Regurgitation occurs during diastole when aortic valve leaflets remain competent during. This results in a portion of the LV stroke volume leaking back into the left ventricle from the aorta.
What is the consequence of systolic hypertension in aortic regurgitation?
It contributes to a cycle of progressive dilation of the aortic root and worsening of aortic regurgitation.
What is a common symptom of aortic regurgitation?
Early or mid-diastolic murmur at the left sternal border
This murmur is characterized by a low-pitched diastolic rumble known as the Austin-Flint murmur.
What are the characteristics of hyperdynamic circulation in aortic regurgitation?
Widened pulse pressure, decreased DBP, bounding pulses
Hyperdynamic circulation is often accompanied by symptoms like dyspnea, orthopnea, fatigue, and coronary ischemia.
What happens in acute aortic regurgitation?
Severe left ventricular volume overload, coronary ischemia, rapid deterioration of LV function, and heart failure
Immediate surgical intervention is necessary due to the acute volume overload.
What does the Austin-Flint murmur result from?
Fluttering of the mitral valve caused by the regurgitant jet from the leaking aortic valve
This murmur is a low-pitched diastolic rumble.
When do symptoms of aortic regurgitation typically appear?
Symptoms may not appear until left ventricular dysfunction is present
This delay in symptom onset can complicate diagnosis.
What diagnostic tools are used for aortic regurgitation?
EKG, CXR, echocardiogram
These tools can show LV enlargement and hypertrophy, leaflet prolapse or perforation, and associated aortic abnormalities.
What is the medical treatment goal for aortic regurgitation?
Decrease systolic hypertension, reduce LV wall stress, and improve LV function
Medications used include diuretics, ACE inhibitors, and calcium channel blockers.
What are the surgical treatment options for aortic regurgitation?
Aortic valve replacement (AVR), aortic root replacement
The choice of surgical intervention depends on the etiology of the AR.
What are key anesthetic considerations in patients with aortic regurgitation?
- Maintain forward LV stroke volume and avoid bradycardia (HR>80)
- Avoid increased SVR
- Minimize myocardial depression (Vasodilator to reduce afterload, Inotrope to increase contractility)
Again, FAST, FORWARD, FULL!
What induction methods are commonly used in anesthesia for aortic regurgitation?
- GA with inhaled anesthetic or IV drugs
- NMBDs w/ minimal or no effect on BP
It is important to avoid decreased heart rate or increased systemic vascular resistance (SVR), although the modest increase in heart rate associated with pancuronium administration could be helpful in patients with aortic regurgitation…
Fill in the blank: With aortic regurgitation, intravascular fluid volume should be maintained at _______ levels to provide adequate preload.
[normal]
This is crucial for optimizing cardiac output in patients with aortic regurgitation.
What type of echocardiogram should be used as a diagnostic tool for aortic regurgitation?
Transesophageal echocardiogram
This type of echocardiogram provides detailed images of the heart structures.
