May 19th, 2014
Case: A Young Pregnant Woman with Prior Valvular Disease and Increasing Dyspnea on Exertion
Reva Balakrishnan, MD, MPH and James Fang, MD
A 22-year-old woman is referred for cardiac evaluation during the 35th week of her first pregnancy. She had undergone mechanical aortic and mitral valve replacement for unknown valvular disease after immigrating to the U.S. at age 12. She has had no cardiology follow-up for the past 3 years. She first noticed fatigue and shortness of breath on exertion 2 years ago. Now, in the late stages of pregnancy, she notes a marked increase in dyspnea on exertion (she walks about 3 blocks before needing to rest), trace lower-extremity edema, and no orthopnea. Her current medications include warfarin and prenatal vitamins.
Transthoracic echocardiography reveals normal LV systolic function, a mean aortic valve gradient of 108 mm Hg, a peak gradient of 158 mm Hg, a peak velocity of 7 m/sec, and a mean mitral valve gradient of 12 mm Hg. The valve shows no evidence of thrombus. A chest x-ray is normal.
Questions:
- How would you further assess this patient’s current symptoms?
- What additional information, if any, would be helpful in deciding how to manage this patient?
- How would you further evaluate this patient’s valves?
- What recommendations would you make regarding anticoagulation?
- Would you make specific recommendations regarding peripartum management (e.g., method of delivery, anesthesia, hemodynamic monitoring)?
Response:
May 27, 2014
1. How would you further assess this patient’s current symptoms?
The clinical dilemma is sorting out the cause of the increased velocities through the mitral and aortic valves. Because pregnancy is associated with a 50% increase in circulating blood volume and a subsequent increase in cardiac output, blood velocity through any fixed orifice will rise and result in a transvalvular gradient; anemia also exacerbates this phenomenon. However, in the presence of a mechanical valve, lack of anticoagulation in the hypercoagulable state of pregnancy, and a history of exertional dyspnea, prosthetic valvular stenosis (e.g., from thrombosis, pannus ingrowth, or both) is in the differential diagnosis. The patient should undergo transesophageal echocardiography to further assess function of the valves. If diagnostic uncertainty persists, fluoroscopy or CT imaging may be of use.
2. What additional information, if any, would be helpful in deciding how to manage this patient?
Measuring B-type natriuretic peptide may be useful in assessing the wall stress, although mitral stenosis may be protecting the LV from volume overload. In this case, there should also be concomitant pulmonary hypertension, which should be assessed on echocardiogram. If not assessable noninvasively, right heart catheterization would be reasonable.
3. How would you further evaluate this patient’s valves?
In rare instances, direct LV puncture can be used to assess intraventricular pressures when the aortic and mitral valves are both mechanical. In this case, noninvasive means should be sufficient for a diagnosis.
4. What recommendations would you make regarding anticoagulation?
Anticoagulation should be initiated in the hospital with either low-molecular-weight or unfractionated heparin. Plans for controlled delivery of the baby should be made.
5. Would you make specific recommendations regarding peripartum management (e.g., method of delivery, anesthesia, hemodynamic monitoring)?
A heart team is critical to this patient’s management. Obstetricians, cardiac surgeons, and cardiologists who specialize in high-risk patients must assess all information in order to make recommendations regarding delivery with or without concomitant surgical approaches to the valvular disease, if any is identified. Because cardiac surgery in the mother poses significant risk to mother and fetus, such an approach is generally recommended only for advanced, medically refractory symptoms. If the valves have significant dysfunction, hemodynamic monitoring should be considered at the time of delivery. In an extreme case of heart failure, immediate postpartum valve replacement may be necessary. Spontaneous vaginal delivery, given the associated extreme hemodynamic changes, is likely to be avoided.
Follow-up
June 2, 2014
As suggested, this difficult case became a multidisciplinary discussion among OB/Gyn, anesthesia, CV surgery, and cardiology. Subsequently obtained outside hospital records revealed that the patient had 2 prior echocardiograms showing similarly elevated gradients. Given her unclear adherence to warfarin and symptoms that had started before pregnancy, either pannus ingrowth, chronic thrombosis, or both were assumed to be the cause of the valve dysfunction. As the 2014 ACCF/AHA valvular heart disease guidelines recommend, the patient was continued on warfarin (class IB) in addition to low-dose aspirin. Heparin and low-molecular-weight heparin (LMWH) are associated with valve thrombosis in pregnancy; LMWH confers a lower risk for thrombosis if anti-Xa levels are monitored closely and is recommended only in the first trimester if the daily dose of warfarin exceeds 5 mg.
Before her valve could be evaluated further, the patient began to have contractions and was admitted for preterm labor. Anticoagulation was switched from warfarin to an intravenous unfractionated heparin drip. Monitoring showed fetal distress, and the patient was taken emergently for a C-section with a cardiology team that used general anesthesia in a controlled setting with anesthetics that are associated with a lower risk for hypotension. A pulmonary artery catheter was not used during delivery, as the patient did not appear to be in decompensated heart failure on admission. The baby was delivered without complications, and the mother was monitored postpartum in the CCU, given the expected hemodynamic changes (increase in cardiac output and intravascular volume due to uterine involution).
A transthoracic echocardiogram, performed 1 week postpartum, showed improved but still severe gradients across both the aortic and mitral valves. The patient transitioned back to anticoagulation with warfarin. A transesophageal echocardiogram was unable to establish the cause of the valve dysfunction. Postpartum, the patient’s dyspnea improved, but she remained symptomatic with limited exercise tolerance. She underwent double mechanical valve replacement 1 month postpartum; both the aortic and mitral valves showed pannus ingrowth.
7 Responses to “Case: A Young Pregnant Woman with Prior Valvular Disease and Increasing Dyspnea on Exertion”
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How would you further assess this patient’s current symptoms?
EKGs and echocardiograms usually is enough, assesment of functional capacity and pulmonary pressure is very useful information. I wouldn’t took the x ray.
What additional information, if any, would be helpful in deciding how to manage this patient?
Monitor systemic blood pressure, functional capacity. Foetus assessment and consider induction of pulmonary maturity.
How would you further evaluate this patient’s valves?
The objective is to continue the pregnancy until the foetus is viable and to deliver the baby by vaginal delivery or caesarean. If is not possible consider ballon valvotomy but usually is contraindicated if the aortic valve is calcified or there is already significant regurgitation. As far as I know there is no experience with TAVI in cases like this.
What recommendations would you make regarding anticoagulation?
Vitamin K antagonists cross the placenta and increase the risk of early abortion, embryopathy and prematurity but she is in the 35th week of pregnancy. Change to percutaneous or intravenous heparin at the 36th week to avoid the risk of neonatal intracranial haemorrhage during delivery. Heparin should be withdrawn 4 h before caesarean section or at the onset of labour and resumed 6 – 12 h after either surgical or vaginal delivery.
Would you make specific recommendations regarding peripartum management (e.g., method of delivery, anesthesia, hemodynamic monitoring)?
Induction of pulmonary maturity, if the patient is stable vaginal delivery in this case is probable a Caesarean section use epidural analgesia, hemodynamic monitoring and blood gases. The use of endocarditis prophylactic antibiotic is controversial in vaginal delivery and you have to use it in c section.
Ad. In this case you must have to use endocarditis prophylaxis and of course the valvotomy and TAVI are not applicable is this case only with native valves. Pregnancy increase 30 50% the cardiac output, which is mainly achieved by an increase in stroke volume, this explain a great deal on this case and you have to consider this hemodynamic changes largely returned to normal within 1 - 3 days in most cases but may take up to a week after this period is good time to reevaluate the case.
Thank you for your response. Valvotomy or TAVI were not options in this case as our patient had mechanical valves.
I pose several questions –
1)Should we still be concerned about valve thrombosis?
2)Which would be worse in the setting of severe aortic and mitral stenosis – the hemodynamics of vaginal delivery (inc CO, valsalva with bearing down, tachycardia), or the fluid shift/blood loss and risk of systemic hypotension from spinal anesthesia with c-section?
1)Should we still be concerned about valve thrombosis?
Always, even with anticouagulation the patient is at risk of thrombosis, pregnancies produce and hypercoagulation state. You have to pay special attention to the echocardiogram, this increase of velocities and gradient are from obstruction or the hyperdynamic state.
2)Which would be worse in the setting of severe aortic and mitral stenosis – the hemodynamics of vaginal delivery (inc CO, valsalva with bearing down, tachycardia), or the fluid shift/blood loss and risk of systemic hypotension from spinal anesthesia with c-section?
If the patient is stable usually vaginal delivery is OK in the untestable patient c-section is the best option. General and epidural anesthesia increase cardiac output but if the delivery is spontaneous this increase in CO is greater. Don’t try to induce the delivery. Caesarean section avoid the physical stress of labour, but it is not free from hemodynamic consequences related to anaesthesia specially if is general and you use assisted ventilation also you have to take steps to reduce the risk of venous thromboembolism.
You must take in consideration cardiac output increase during the early postpartum period because additional blood reaches the circulation from the contracting uterus so you have an increment the preload, so many patients at risk often develop pulmonary edema. You can use diuretic to avoid this.
If necessary and possible, in the context of aortic stenosis you can lower the postload and for the mitral stenosis you can lower the heart rate and diuretics for congestion you have to use them wisely.
In this case is very important the opinion of the obstetrician,
By no cardiology followup,was there also no monitoring of INR and ascertainment of intensity and stability of anticoagulation status? What were PA pressure estimates,this being the principle driver of peripartum morbidity and mortality?
Fluoroscopy /TEE could assess mechanical leaflet movement and lend support to the primary mechanism of patient prosthetic mismatch amplified by the physiology of late term pregnancy as cause of high transvalvular gradients.
The protracted and repetitive temporal dispersion of the physiological requisites of vaginal delivery would steer one clear of this modality.
Heparin interrupted 4-6 hours prior to caesarian section with general anesthesia(cardiovascular anesthesiologist)and consider pulmonary artery pressure monitoring(PA catheter) intra and post operatively. Heparin restarted ASAP when hemostasis is secure.
Then, need to consider 1.) valve re-replacement with valve orifice size appropriate to body mass 2.) counseling re: repeat pregnancy risk and birth control. Quite a cascade of decision making and procedural sequencing(particularly if tubal ligation is chosen as method of prophylaxis)
Valve thrombosis is possible; patient took prenata vitamins. Do they contain Vitamin K?
This is a challenging case and requires a team of cardiologists, obstetricians, neonatologists and anesthesiologists, perhaps also cardiac surgeons. The dyspnea, which is getting worse, is an ominous sign.
At 35 weeks the fetus is viable, unless there is a problem in intrauterine growth, which of course in itself would be a reason to haste delivery. Helping pulmonary maturation with steroids would probably be advisable.
I believe an elective C-section would be the safest alternative. Bridging therapy with heparin should be initiated well in advance.
The best anesthesia would probably be a carefully titrated epidural, if possible and if the coagulation status allows.
The mother will need extensive monitoring during and after delivery, because the consequences of the rapid hemodynamic changes can be unpredictabe. She might require urgent valve replacement.
Unfortunately, cases like this, which arrive at our doorstep in the late stages of pregnancy, are not uncommon. Lay persons underestimate the hemodynamic stress of pregnancy and delivery, which a healthy young woman can sail through, but can be life-threatening for a woman with cardiac problems.