Shunt Lesions

 

Cardiac complications

Obstetric complications

Mode of delivery

Puerperium

Risk of transmission

WHO categories

Unrepaired ASD

Atrial arrhythmias

Prematurity

Vaginal delivery

Thromboprophylaxis

5 %

2

Thromboembolic event

SGA

Epidural

Repaired ASD

NO

General population

Vaginal delivery


5 %

1

Atrial arrythmiasa

Epidural

Small VSD or small PDA

NO

Pre-eclampsia

Vaginal delivery


3 %

1

Epidural

Repaired AVSD

Arrhythmia (10 %)

Pre-eclampsia

Vaginal delivery

24 h of maternal monitoring

8 %

2 or 3

Cardiac decompensation (2 %)

Preterm labour

Epidural

Thromboprophylaxis

SGA [1]

Eisenmenger syndrome

Right heart failure

Preterm labour

C-section

Intensive care monitoring

Depends on type of CHD

4

Thrombosis

Prematurity

Multidisciplinary team involvement

Death (30 %)

SGA


SGA small for gestational age

aIF ASD repaired in adult age





9.2.2.3 Atrioventricular Septal Defects


Patients with repaired atrioventricular septal defects (AVSD) are a separate population in terms of complications during pregnancy. In the large meta-analysis of pregnant patients with CHD [3], the risk of cardiac, obstetric, fetal and neonatal complications was higher than in other shunt lesions. The majority of patients with AVSD repaired in infancy are in excellent health and has a good New York Heart Association (NYHA) class, but residual lesions, mainly left AV-valvular regurgitation (LAVVR), are prevalent [17]. The risk of complications of an unrepaired partial AVSD is presumed to be similar to an unrepaired ostium secundum ASD, if no significant LAVVR is present. An unrepaired common AVSD in adult life is almost always associated with irreversible pulmonary arterial hypertension, and pregnancy in this situation carries a prohibitively high risk.

The most frequent cardiac complication observed during pregnancy in patients with repaired AVSD is arrhythmia [3] The larger the left atrial dimensions in relation to the degree of the LAVVR, then the greater the risk of arrhythmia, while those with arrhythmias outside pregnancy are also at a higher risk of occurrence during pregnancy [18]. Heterotaxy is prevalent in newborns with AVSD [19]. The risk of arrhythmias, both right and left atrial isomerism, is higher in adult patients than in patients with usual atrial arrangement [20]. Other complications described are persistence of pregnancy-related NYHA class deterioration as well as deterioration of pre-existing LAVVR [18]. Cardiac decompensation is described in 1–2 % of pregnancies [3, 18], usually managed medically, with urgent mitral valve replacement being exceptional in this setting. Obstetric and fetal complications are also higher in this population, especially when a maternal cardiac complication is present. Risk of transmission is described as high as 8 % (Fig. 9.1).

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Fig. 9.1
You can see fetal echocardiography of an AVSD at 24 weeks (Courtesy of Dr Q Ferrer, Department of Pediatric Cardiology and Fetal-Maternal Medicine Department)




9.3 Management of Shunt Lesions During Pregnancy


Patients with repaired ASD during infancy do not need multidisciplinary team follow-up, provided that there has been a good preconception assessment and patients are in good condition without residual lesions, and pulmonary arterial hypertension is ruled out. However, the risk of transmission of congenital heart disease is higher than in the general population, and fetal echocardiography is recommended [21, 22]. See Fig. 9.1.

In contrast, patients with an ASD who had a late repair or whose ASD is unrepaired, and those with an AVSD, whether repaired or not, need multidisciplinary team follow-up.

Frequency of cardiac follow-up depends on residual lesions. In AVSD, cardiac decompensation is possible. If LAVV regurgitation is significant, clinical and echocardiographic close follow-up is required with frequent echocardiography. If significant atrial arrhythmias are detected, then anticoagulation and rhythm or rate control should be considered, depending on hemodynamic status; therapeutic low molecular heparin should be given twice or three times per day and be monitored with peak (3–4 h after injection) and trough anti-Xa levels. Metoprolol is the safest beta-blocker for the fetus.

In the presence of an unrepaired ASD, there is a high risk of paradoxical embolism; consequently, thromboprophylaxis should be given to all those with additional risk factors. The need for thromboprophylaxis should be assessed antepartum, postpartum and at any time the patient transitions from the outpatient to the inpatient setting.

In left-to-right shunts, maternal deterioration is not frequent, and spontaneous vaginal delivery is advised in most cases, with epidural anaesthesia. Cardiac indication of Caesarean section is rare in the setting of left-to-right shunt except if pulmonary hypertension is present. Recommendations for care during delivery and puerperium of a patient with repaired AVSD and significant LAVVR are showed in Fig. 9.2.

A338684_1_En_9_Fig2_HTML.gif


Fig. 9.2
You can see delivery plan of a patient with repaired AVSD and severe left atrioventricular valve regurgitation

Labour can be conducted with the mother in the left lateral position to avoid inferior vena caval compression and maintain venous return. The second stage can be assisted with forceps or vacuum extraction if necessary. Prolonged labour should be avoided. In addition to fetal monitoring, maternal ECG monitoring should be performed to detect any arrhythmia during labour and the puerperium.


9.3.1 Management of Patients with Eisenmenger Syndrome


PAH accompanies large left-to-right shunts; pulmonary vascular obstructive disease may develop in adults but occurs much later in pre-tricuspidic shunt than in high-pressure left-to-right shunts. In young women with unrepaired ostium secundum ASD or sinus venosus, the rate of pulmonary arterial hypertension is presumed to be low, around 5–10 % at maximum [23]. There is little information regarding cases of adult presentation of unrepaired partial AVSD and the rate of associated pulmonary arterial hypertension, but numbers are presumably similar to other pre-tricuspidic lesions. Small restrictive VSDs and small PDAs will not have associated PAH. In contrast, a large unrepaired VSD, a large PDA or unrepaired common AVSD at the childbearing age have a high probability of irreversible pulmonary arterial hypertension, shunt reversal and Eisenmenger syndrome.

For further information on haemodynamic impact of pregnancy in Eisenmenger syndrome, see Chaps. 16 and 17.

If the patient with Eisenmenger syndrome decided to continue with the pregnancy, a multidisciplinary team should be involved during the whole pregnancy, delivery and postpartum period. Due to low oxygen saturation, especially if below 85 %, a high risk of spontaneous abortion and fetal loss is present [2426]. Maternal risk of decompensation is high, despite oxygen supplementation and strict balance of fluids [27]. Prostanoids (i.v. prostacyclin or inhaled iloprost) and inhibitors of phosphodiesterase type 5 are used, since there is no evidence of teratogenicity in animals. Endothelin receptor antagonists are generally avoided because of teratogenicity seen in animal testing [28].

Obstetric and fetal complications are common, as limited cardiac output and low oxygen saturation both contribute to placental insufficiency, causing intrauterine growth retardation (IUGR) and the need for early delivery [3, 27]. Thromboprophylaxis is usually prescribed, but full anticoagulation is controversial because of concerns about bleeding [10]. Avoiding possible paradoxical embolism through the care of peripheral lines and using air filters is wise during all admissions [29].

The majority of cases are delivered by Caesarean section as heart failure is usually present during the third trimester, despite good cardiac function prior to pregnancy. This has a class IIa recommendation in the ESC guidelines [10]. A multidisciplinary team involving an obstetrician, cardiologist and anaesthetist is mandatory. During delivery, pain and anxiety should be avoided, as well as hypotension due to drug administration. Small incremental doses must be given if epidural anaesthesia is used to avoid hypotension [30]. Invasive monitoring of systemic arterial pressure and a central venous pressure is probably indicated in all cases. Nitric oxide use may be helpful during anaesthesia.

During puerperium, there is an increase in venous return from the uterus and inferior vena caval decompression, resulting in additional overload to the already compromised right ventricle. For this reason, the puerperium is the highest risk period for mortality in Eisenmenger syndrome. Maternal ICU stay will be mandatory for more than 48 h and hospitalisation of at least 1 week postpartum. Fifty percent of mortality in pregnant patients with Eisenmenger syndrome has been observed during the puerperium [31].

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Aug 12, 2017 | Posted by in CARDIOLOGY | Comments Off on Shunt Lesions
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