Corticosteroid prophylaxis for fetal immaturity in a pregnant patient with atrial myxoma

Abstract

We report a case of a woman at 32nd gestational week, admitted for resting dyspnea, showing left atrial (LA) myxoma.

Cardiac myxomas are the most common primary benign tumors of the heart. The incidence of cardiac myxomas diagnosed in pregnancy is extremely low.

In the present case, cesarean delivery and concomitant surgical resection of LA myxoma were both delayed after corticosteroid prophylaxis in order to reduce neonatal cerebral, intestinal, and pulmonary complications.

<Learning objective: The rarity of these cases makes the management more related to anecdotal experiences. In our case, the gestational age was lower than 34th week, but the fetus was sufficiently large to be delivered before heart surgery with low risk of prematurity complications after an adequate corticosteroid prophylaxis. A waiting approach with several days of corticosteroid prophylaxis was successfully adopted. When the pregnant hemodynamics are stable with low risk of complications, heart surgery should be delayed after corticosteroid prophylaxis.>

Introduction

Myxoma is the most common primary cardiac tumor, ranging from 30% to 50% of all primary cardiac tumors; nevertheless, it should be considered a rare finding with an annual incidence of 0.5 per million [1]. There is a female predominance, as 65% of myxomas occur in women, but its prevalence during pregnancy remains extremely low [2]. Few cases have been reported in the literature [3], [4], [5], [6]. In the general population, prompt surgical resection of myxoma is recommended; however, in pregnancy, the decision-making process becomes more complex due to potential neonatal complications, related to low gestational age, and the potential myxoma embolization for both mother and fetus.

In the present case, both, cesarean delivery and concomitant surgical resection of LA myxoma were both delayed after corticosteroid prophylaxis in order to reduce neonatal cerebral, intestinal, and pulmonary complications.

Case report

A 32-year-old nulliparous female at 32nd gestational week was admitted to our unit with a diagnosis of left atrial (LA) mass. The patient complained of resting dyspnea. The blood samples and electrocardiogram (ECG) did not show any alteration. Trans-thoracic, before, and trans-esophageal echocardiography (TEE) showed the presence of LA mass of 5 cm × 3 cm, attached to left atrium dome with a sessile base of implant, and the presence of calcifications and necrotic areas inside. The mitral valve was not involved (Fig. 1). Cardiac magnetic resonance (CMR) was performed to better visualize the mass extension, the anatomical rapports, and for tissue-typing. CMR confirmed the mass size (5 cm × 3.7 cm); the LA mass originated from the superior portion of interatrial septum with partial compression of right pulmonary veins (Fig. 2), the latter might have explained the symptoms.

Fig. 1.

Trans-esophageal echocardiography: a sessile mass originating from the superior portion of interatrial septum.

Fig. 2.

Four-chamber cardiac magnetic resonance view: a sessile mass originating from the superior portion of interatrial septum with partial compression of right pulmonary veins (white arrow).

The typical localization of the LA prompted us toward a diagnosis of LA myxoma rather than malignancy or metastatic tumor; however, given the pregnancy, the patient was not submitted to any other invasive exam (i.e. computed tomography scan or positron emission tomography). The low gestational age, the stable hemodynamics (normal blood pressure and heart rate, preserved ejection fraction, and good urine output), and the low mobility of the LA mass led to a more waiting approach, starting corticosteroid prophylaxis for 3 days (12 mg of betamethasone i.m. per day) to induce fetal maturation and oxytocin receptor-blocker to reduce uterine contractions. Moreover, dyspnea improved with a very low-dose of oral diuretics.

After the prophylaxis, the patient was submitted to combined cesarean delivery and atrial myxoma resection.

Firstly, a cesarean procedure was performed under subarachnoideal anesthesia, delivering a healthy newborn weighing 1710 g; during the cesarean procedure, a TEE was performed. Then, after cesarean section closure, the patient was submitted to the second step of the operation under general anesthesia. Median sternotomy was performed. After bicaval and aortic cannulation, cardioplegic arrest was obtained with antegrade HTK crystalloid cardioplegia. A bi-atriatomy incision was performed. The LA mass was implanted close to the ostium of right pulmonary veins. The mass and its base of implant were completely resected. Atrial reconstruction and closure was performed with the aid of equine pericardial patch. Histology revealed the nature of the mass as an atrial myxoma.

The patient was discharged from the intensive care unit after 35 h and from postoperative ward after 9 days. The postoperative course was uneventful.

Discussion

A review article [3] reported 2 cases of atrial myxoma diagnosed during pregnancy along with a series of another 17 patients. Both reported cases were surgically treated in order to reduce the risk of embolization. Berberovic et al. [6] reported the case of a diabetic pregnant woman with pre-eclampsia, where LA myxoma was diagnosed 2 days after cesarean delivery due to brain embolisms. Hence, in this case, the management was similar to the general population. In the case reported by Koukis et al. [5], the surgical resection was mandatory because the woman was 6 weeks pregnant and the mass involved the mitral valve causing mitral leaflet malcoaptation and regurgitation. The case by Sindjelic et al. [4] was 38 weeks pregnant and so the decision-making process was easier. Among the 17 cases reported in a literature review by John et al. [3], 12 (70%) underwent successful surgical resection of atrial myxomas during pregnancy due to low gestational age, 1 (6%) mother refused the surgical treatment, and 4 (24%) had an elective delivery before surgical excision. Conversely, our case fell into a gray zone, where waiting for a few more days along with corticosteroid prophylaxis allowed her to reach a safer gestational age for the fetus without any risk for the mother.

However, the rarity of these cases makes the management referring to more anecdotal experiences than actual statistics. The management of this particular situation should consider many aspects: the acuity of the cardiac pathology, the risk of premature birth, and the potential detrimental effects of cardiopulmonary bypass on mother and fetus.

Cardiac myxoma is often considered an emergency in cardiac surgery either in the presence of hemodynamic alterations due to atrio-ventricular valve inflow obstruction or in case of high risk for embolization. Myxomas with villous surfaces are more prone to produce emboli as a result of clot formation. In addition, pregnancy induces a pro-thrombotic state with an overproduction of fibrinogen and clotting factors, so making pregnancy a high risk of thrombus formation.

In our case, hemodynamics was stable and sessile aspect of LA mass without villous surface suggested a low-risk likelihood for embolization.

The natural production of surfactant increase at approximately week 30–32 and babies born after the end of 32nd week could have sufficient surfactant to breathe normally; however, the delivery before the 34th week of gestational age is not safe enough for neonatal acute respiratory distress syndrome, cerebral, and intestinal complications. In case of premature birth, corticosteroid prophylaxis can reduce the risk of these complications, improving both pulmonary surfactal production and cerebral and intestinal maturation.

Finally, the risk of cardiopulmonary bypass during pregnancy is reported to be similar to non-pregnant women submitted to cardiac surgery unless there is an emergency [7], but fetal mortality rate ranges from 16% to 33%, with a significant reduction when cardiac surgery was postponed until an advanced gestational age [8].

In our case, gestational age was lower than 34th week but the fetus was sufficiently developed to be delivered before heart surgery with low risk of prematurity complications after an adequate corticosteroid prophylaxis. Hence, a waiting approach with several days of corticosteroid prophylaxis was successfully adopted.

In conclusion, the management of pregnant patients needing cardiac surgery is complex. When the pregnancy is hemodynamically stable with low-risk of complications (embolization, malignant arrhythmias, etc.), heart surgery should be delayed until after corticosteroid prophylaxis.

Conflict of interest

The authors declare no conflict of interest.