Transcript Interferences to Oxygen: congenital anomalies and cardiovascular

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Mitral Stenosis
Typically caused by rheumatic carditis from
rheumatic fever
 Valve leaflets fuse, stiffen
 Chordae tendineae contract, shorten
 Valve opening narrows
 Compromises blood flow from left atrium to left
ventricle
 Resulting in rise in L atrial pressure, L atrium
dilitation, increased pulmonary artery pressure, R
ventricular hypertrophy
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Mitral Regurgitation (Insufficiency)
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Failure of closure of mitral valve during systole due
to fibrotic and calcific changes
Blood leaks from L atrium to L ventricle along with
normal blood flow
Results in increased volume to be ejected during
next systole
Leading to dilation of L atrium and ventricles with
hypertrophy
Rheumatic fever primary cause
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Mitral Valve Prolapse
Enlargement of valvular leaflets which prolapse into
L atrium during systole.
 Usually benign in nature but may progress to
pronounced mitral regurgitation.
 Most are asymptomatic
 Most common in women between 20 and 54 years of
age
 Genetic
 Auscultation of midsystolic click with late systolic
murmur audible at apex.
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Aortic stenosis
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Aortic valve orifice narrows and obstructs L
ventricular outflow during systole
Leading to increased resistance to efection or
afterload
Resulting in ventricular hypertrophy
Predominately caused by congenital
malformation/disease
Most common valvular disorder in countries with
aging populations
 Caused by atherosclerosis and degenerative
calcification
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80% men
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Aortic regurgitations (insufficiency)
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Aortic valve leaflets do not close properly during
diastole
Leads to regurgitation of blood from the aorta back
into L ventricle during diastole
L ventricle dilates with eventual hypertrophy
Asymptomatic
When patient becomes symptomatic, symptoms due
to L ventricular failure
Bounding arterial pulse, widened pulse pressure,
high-pitched blowing decrescendo diastolic murmur
Causes: infective endocarditis, congenital anatomic
aortic valvular abnormalities, htn, Marfan syndrome
75% are men
Nonsurgical
Drug therapy
Diuretics
Beta Blockers
Digoxin
Nitrates
Calcium Channel Blockers
Prophylactic antibiotic therapy
Anticoagulants
Antidysrhythmics
Rest
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Surgical Management
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Reparative procedures
 Improved function of valve
 Less problem with complications
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Balloon valvuloplasty
 Patients selected for this are typically older, high risk
for surgical complications or have refused operative
treatment
 Benefits short lived
 Postop precautions consistent with those for cardiac
catheterization
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Direct Commissurotomy
 Requires open heart surgery and cardiopulmonary
bypass
 Removal of thrombi, cutting loose of fused leaflets,
debridement of calcium from valve
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Mitral Valve Annuloplasty
 Reconstruction of valve for acquired mitral
insufficiency
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Valve replacement
 Xenograft
 Porcine or bovine
 Risk for clot formation minimized
 No need for long term anticoagulant therapy
 Typically used for the older patient
 Prosthetic valve
 More durable
 Used in younger patients
 Must have long term anticoagulation
 See chart 38-9 for patient education
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Microbial infection involving endocardium
Found in Iv drug abusers, patients having had
valve replacements, bacteremia, structural
cardiac defects
Mortality high – early detection key
> 90% develop murmurs
Heart failure most common complication
See chart 38-10 Key features of infective
endocarditis
Interventions = antimicrobials, rest balanced
with activity, supportive care for heart failure
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Most common procedure = orthotopic
transplantation
Donor must be comparable body weight, ABO
compatible
Heart must be transplanted within 6 hours of
harvesting
See criteria for candidate selection pg 774
Biggest factor to remember is that vagus nerve
will no longer function
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Atropine, digitalis and carotid sinus pressure
ineffective
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Require life long immunosuppressants
Long term complications
Coronary artery vasculopathy
 Organ rejection
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See Key Points at end of chapter 38
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Acyanotic
 Do not cause deoxygenation
 Skin and mucous membrane color is usually pink
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Atrial septal defect
 Left to right shunt
 Opening between L and R atria
 Surgical closure or patch of defect
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Ventricular septal defect
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Left to right shunt
Increased pulmonary blood flow
May have spontaneous closure
Surgical patching may be required
Prophylactic antibiotics for prevention of endocarditis
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Coarctation of the aorta
 Narrowing of the descending aorta restricting blood
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flow leaving heart
Progressive, leading to chf
BP difference of 20mm between upper and lower
extremities
Upper pulses full, lower pulses weak
CVA secondary to htn in upper circulation
Endocarditis prophylaxis
Surgical resection and patch of coarctation
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Cyanotic heart defects
 Heart conditions that couse blood to contain less oxygen than
required
 Skin and mucous membranes usually pale to blue
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Tetrology of Fallot
 4 defects that combine to allow blood flow to bypass lungs
and enter L side of heart  R to L shunt
 Unoxygenated blood enters body circulation leading to
cyanosis
 Defects:
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Pulmonic stenosis
R ventricular hypertrophy
Ventricular septal defect
Overriding aorta
 Acidosis occurs
 TET spells: hypercyanosis = transient periods of increased R
to L shunting of blood
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Transposition of the great vessels
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Aorta arises from R ventricle, pulmonary artery
arises from L ventricle
 This is inconsistent with life
Other anomalies exist that increase mixing of blood
between the two separate circulations to promote
oxygenation
 R to L shunting of blood occurs
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Aneurysm – permanent dilation of an artery to at least
2 times its normal diameter
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Fusiform = affects entire circumference of artery
Saccular = outpouching affecting only a distinct portion of
artery
True aneurysm = arterial wall weakened by congenital or
acquired problems
False aneurysm = occurs as a result of trauma or injury to all 3
layers of the artery wall
Abdominal aortic aneurysms (AAA) account for 75% of all
aneurysms
Atherosclerosis is most common cause
AAA more common in men than women
S/S related to pressure on surrounding structures or rupture
 Rupture is life threatening
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Interventions
Nonsurgical to monitor growth of affected area and
maintain BP at a normal level
 Surgical management is the excision of the aneurysm
from the area with the placement of a woven Dacron
graft
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 Pre and post op care consistent for those undergoing
surgery with general anesthesia