Aortic Stenosis Flashcards
How is AS caused?
Congenital or Acquired
List Acquired causes of AS
- Rheumatic valve disease, calcification of the tri-leaflet valve, Bicuspid aortic valve, Alkaptonuria, SLE, Ochronosis, Irradiation, homozygous type II lipoproteinemia, and metabolic diseases such as Fabry disease. Mineral metabolism disturbances, such as ESRD. Obstruction to the left ventricular (LV) outflow can occur above or below the valve, causing supravalvular stenosis and subvalvular stenosis, respectively. Hypertrophic cardiomyopathy can cause dynamic subvalvular stenosis.
List Congenital cause(s) of AS
abnormal valve ie bicuspid Ao valve in < 70 yrs, with superimposed calcification
What evaluation do you perform for AS?
Preconceptual - determine h/o cardiac sxs such as arrythmias, baseline exercise tolerance and functional class/echocardiogram, anatomy and hemodynamics of valve lesion, ventricular function and pulmonary pressures
What is mild vs severe AS?
MIld: >1.5 cm valve area with peak gradient < 50 mmHg. Well tolerated in pregnancy
Severe: < 1 cm valve area, peak gradient > 75 mmHg or EF <55%. Leads to fixed CO.
How do you follow a patient with AS?
H&P qtri, monitor s/s, changes in functional class, serial echo for any changes in s/s
What medications treat AS?
β‐blockers, hydralazine, diuretics and digoxin
How do you preconceptually counsel AS pts?
effective contraception until pregnancy is desired, consider valve repair or replacement if symptoms exist, adjust drugs
List treatment options for AS in pregnancy
change to only necessary drugs that are not contraindicated in pregnancy, control sxs with medical treatment, bedrest and oxygen, valvuloplasty, valve repair or replacement
What are delivery considerations for AS?
short vaginal delivery with excellent anesthesia (minimize tachycardia and hypertension due to pain and anxiety), left lateral decubitus position, CS per obstetric indications, invasive monitoring if needed, medical treatment to optimize loading conditions and to treat pulmonary edema. Minimize pushing, consider forceps or VAVD (to avoid the sudden rise in systemic vascular resistance and drop in systemic venous return that occurs with maternal pushing). Endocarditis prophylaxis for vaginal deliveries.
Why is vaginal or cesarean preferred for AS?
vaginal delivery with adequate pain control is preferred
Caesarean section results in greater hemodynamic changes and more blood loss
Management goals of AS
avoid hypotension (BP nec to maintain coronary perfusion), avoid decreased venous blood return and preload (valsalva, excessive blood loss), avoid bradycardia (it will decreased CO given fixed SV) and avoid hypervolemia (leads to pulmonary edema).
Complications of AS
Maternal - heart failure (<10% in moderate AS and 25% in severe AS), aortic dissection (<1% in bicuspid AV with aortic root diameter <50 mm, 1-10% in Marfan syndrome and other HTAD), and rarely arrhythmias.
With increased preload, increase of EDV and activation of Frank-Starling mechanism (LV SV will inc with inc in LV volume); with decreased preload, worsens coronary perfusion Fetal - LBW, IUGR, PTD. The tighter the valve, the higher the fetal risks.
AS Antepartum management
Determine maternal level of care
fetal echocardiogram at 18-22 wks of gestation as the risk of fetal CHD is 4-10% Monitor for IUGR serial growths Daily LD ASA 81 mg initiated between 12-28 wks until delivery for women at high risk for preE Longterm HTN may result with left ventricular hypertrophy with impairment of diastolic function Echocardiogram for patients with pulmonary edema due to risk for peripartum cardiomyopathy or preE
AS intrapartum management
Delivery plan should be determined between 20-30 weeks
Recommend individualized plan with the Pregnancy Heart Team Stable cardiac disease-vaginal delivery 39 wks, cs for ob indications High-risk cardiac disease-may benefit from regional anesthesia, achieving adequate pain relief and minimizing catecholamine release and resultant cardiac output fluctuations IOL between 39-40 wks Anticoagulation stopped appropriately Recommend intrapartum cardiac monitoring for women w/ h/o arrhythmia Antibiotic prophylaxis for high-risk pt for infective endocarditis-previous IE and high risk for it
