Double Valve Replacement in the Pregnant Patient: A Successful Case and Brief Literature Review

INTRODUCTION

Cardiovascular disease is the leading cause of maternal mortality accounting for >25% of maternal deaths; however, the risk of cardiac surgery is very high with poor neonatal outcomes.^[1] The risk of cardiac surgery, especially in a pregnant woman, is very high both for the fetus and the mother. Here, the authors report a patient with a mWHO class IV heart disease who successfully underwent double valve replacement under cardiopulmonary bypass (CPB) and went on to deliver a healthy but premature male baby.

CASE REPORT

A gravida 1 para 0 living 0 abortion 1 patient presented to our center at 27 weeks of gestation with breathlessness of New York Heart Association (NYHA) IV severity. She was diagnosed to have rheumatic heart disease 5 years ago with shortness of breath (NYHA II) and eventually progressed to NYHA IV symptoms. Although she was advised of surgery, the patient had deferred and presented to author’s center.

Her echocardiogram showed severe mitral stenosis (0.9 cm²) with moderate mitral regurgitation, severe pulmonary hypertension pulmonary artery systolic pressure 90 mmHg, and moderate aortic stenosis with severe aortic regurgitation, which qualifies as a World Health Organization category IV heart disease.

She was initially medically managed as acute valvular heart failure with low dose of diuretics, bilevel non-invasive positive pressure ventilation, and vasopressor support. After stabilization, she was deemed a candidate for double valve replacement by the surgical team. After a multidisciplinary discussion with a cardiologist, cardiac surgeon, intensivist, and obstetrician, she was taken up for surgery with high risk. Medical management was continued to ensure the patient reached the second trimester, which is the ideal time for surgery in the pregnant patient. Steroid was administered for lung maturity and left uterine displacement was used throughout surgery to maintain uteroplacental perfusion. Her target mean arterial pressure was maintained above 70 mmHg for which an advanced cardiac output monitoring system (FloTrac) was used and target hemoglobin value was 11 g/dL. Fetal monitoring included non-stress test and cardiotocometry both intra and postoperatively to assess fetal well-being and identify premature uterine contractions with a qualified obstetrician present throughout surgery and available in proximity postoperatively. Normothermic pulsatile CPB was used with the total duration of surgery being 6.5 h and CPB time being 1.5 h. Four packed red blood cells, fresh frozen plasma, and albumin were used during the surgery, and electrolytes and serial arterial blood gas were done and maintained within normal limits by sodium bicarbonate, magnesium, and potassium infusions. Vasopressors including noradrenaline, adrenaline, and dopamine were used to target mean arterial pressure (MAP) of 70 mmHg. Tocolytics including terbutaline were kept on standby however were not used as the obstetric monitoring was uneventful. She was transferred to the post-surgical intensive care unit (ICU) on ventilator, regular point of care ultrasound (POCUS) was used to assess fluid status [[Figures 1 and 2], and vasopressor support was titrated accordingly. For elevated pulmonary artery pressures Dobutamine was used for the first 24 hours as it is short acting in its pharmacokinetics. This was followed by milrinone for next 48 hours. Throughout the perioperative period the patients Mean arterial pressure was maintained at 70 mm Hg and Partial pressure of oxygen (PaO2) was maintained between 80-90 mm Hg. This was done using the FloTrac cardiac output monitoring system. On post-operative day 1, she was extubated and bedside ultrasonography showed a slight reduction in amniotic fluid for which diuretics were withheld, and anticoagulation was maintained with low-molecular-weight heparin and bridged to warfarin for a target INR of 2.5–3.5. Fetal monitoring was further continued even through the postoperative period. Through follow-up, we learned that the patient had delivered a baby boy through cesarean section at 33-week gestation without any major congenital abnormalities; however, her pregnancy was complicated by intrauterine growth retardation, non-reassuring non stress test (NST), and absent end-diastolic flow leading to premature delivery.

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Figure 1:

Subcostal view of the inferior vena cava during inspiration on positive pressure ventilation. The yellow dotted line is the length as measured which is 2.24 cm.

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Figure 2:

Subcostal view of inferior vena cava on expiration during positive pressure ventilation. The yellow dotted line is the length as measured which is 2.24 cm.

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DISCUSSION

Heart disease complicates around 1% of pregnancies with rheumatic being the etiology in over 60% of the cases frequently presenting with mitral and aortic valvular disease in our country.^[2]

We have divided the discussion into 4 parts anesthetic, surgical, intensivist, and perfusion considerations.

CONCLUSION

CPB is a high-risk procedure whose risk exponentially increases with pregnancy. Our patient needed surgery due to persistent and progressive symptoms. In summary, it is possible to perform cardiac surgery on CPB in pregnancy if clinically indicated in a tertiary care setting without complications if the risk is ascertained and preparation is done accordingly. In our center, we followed the basic anesthesia safeguards in pregnancy with additional adjustments by the perfusion team while our surgeons minimized the bypass and cross-clamp time. While the patient did well and was discharged on post operative day 9 (POD9), she had a premature delivery at 33 weeks due to uteroplacental insufficiency. The baby boy was in neonatal ICU for 1 week and discharged alive and healthy. The incidence of premature delivery in patients who continue pregnancy after cardiac surgery is nearly 50%. The literature on cardiac bypass in pregnancy is limited and we hope that our case adds to a series or literature review.