Monali Dudhe*, Neha Saxena*, Rashmi Khadkikar**, Shabnam Qureshi**, A. R. Chauhan***
(* Third Year Resident, ** Assistant Professor, *** Additional Professor. Department of Obstetrics and Gynecology, Seth GS Medical College and
Coarctation of aorta (stenosis commonly located at the junction of the arch of aorta and proximal descending aorta) may be diagnosed for the first time during pregnancy, as most patients are asymptomatic. Dilatation and dissection of the aorta can lead to increased maternal mortality; significant stenosis is a contraindication to pregnancy. However, successful pregnancies have been reported in women with uncorrected coarctation if preconception risk stratification is done. We report a primigravida who presented with chronic hypertension and breathlessness where the diagnosis of coarctation was made incidentally during active labor in view of differences in blood pressure (BP) readings of both arms. She underwent emergency lower segment cesarean section (LSCS) and remained stable postoperatively.
Coarctation of aorta accounts for 5 to 8 % of patients with congenital heart disease. Marked increase in maternal cardiac output and oxygen consumption in pregnancy is associated with left ventricular failure, aortic dissection or rupture, endocarditis and cerebrovascular accidents. Individual risk stratification depends upon the size of the aorta, presence of aneurysm, severity of the coarctation and presence of hypertension.
A 23 year old primigravida with 38 weeks’ of gestation was referred to our tertiary centre for intensive care in view of breathlessness and fever with chills for 3 days. On examination, she had fever, tachycardia (pulse of 136/minute), tachypnea (respiratory rate of 40/minute) and hypertension - blood pressure (BP) of 150/80 mm Hg. On chest auscultation, air entry was reduced in the left lower zone. She had been diagnosed as chronic hypertension at 20 weeks of gestation and was on treatment with tablet methyldopa 250 mg three times a day. She had scoliosis since birth.
All routine hematological investigations were normal; however arterial blood gases revealed pH of 7.3 with oxygen saturation of 91%. Chest radiograph showed patchy opacity in left lower zone suggestive of pneumonia. Chest sonography showed minimal right sided pleural effusion with underlying consolidation; hence a provisional diagnosis of community acquired pneumonia was made. Cardiac cause of hypoxia was not suspected at this time. Obstetric ultrasonography showed severe oligohydramnios.
The patient was started on intravenous antibiotics and oxygen by mask as she was able to maintain her saturation only with 100% oxygen. Antihypertensives were continued. On day 2 of admission, she was transferred to intensive respiratory care unit in view of decreasing oxygen saturation, where she went into spontaneous labor. At this time, in view of differences in BP readings of both arms, right upper limb BP 150/90 mm Hg and left upper limb BP 130/90 mm of Hg, emergency cardiology opinion was taken and 2- D echocardiography was done, which diagnosed severe coarctation of aorta just proximal to the left subclavian artery: diameter of aorta at coarctation site was 6 mm (compared to 14 mm at diaphragm), with peak systolic gradient of 100 mm of Hg across the descending aorta and ejection fraction of 50%. Infective endocarditis prophylaxis was started and emergency LSCS was performed under epidural anesthesia, which was difficult due to scoliosis. Male baby weighing 2.76 kg was delivered with Apgar score of 9/10; liquor amnii was thick meconium stained. The patient was shifted to intensive cardiac unit postoperatively, where her course was uneventful. She was started on tablet metoprolol 12.5 mg daily, and discharged after ten days. CT aortogram postpartum showed hypoplastic aortic arch, as seen in figures 1 and 2. Aortoplasty is planned 6 months postpartum.
Figure 1: CT aortogram (AP and lateral) showing coarctation in lateral view.
Figure 2: Magnified view of coarctation of aorta.
The vascular malformation in coarctation is a defect in the medial layer, giving rise to a prominent posterior infolding or “posterior shelf”. Proliferation of elastic tissue in the intima occurs distal to the coarctation causing intimal dissection or aneurysm formation.
Coarctation may be associated with other cardiovascular anomalies like bicuspid aortic valve, left-sided obstructive or hypoplastic defects and ventricular septal defects, in almost 50% of patients. Extracardiac nonvascular anomalies of head and neck, skeletal, genitourinary, gastrointestinal, or respiratory systems may be present, as in our patient who had thoracic spine scoliosis. Intracranial aneurysm of circle of Willis is seen in 3-5% cases.
Aortic coarctation causes congestive heart failure in early life. In adults, it is usually asymptomatic; however, hypertension, headache, nosebleed, leg cramps, claudication, muscle weakness or neurologic changes may be seen. Clinical examination is diagnostic: systemic hypertension is almost invariable with differences in upper and lower extremity arterial pulses and BP; diminished and delayed pulses distal to the obstruction are characteristic. Hence it should be a routine practice in every patient with systemic arterial hypertension to simultaneously palpate brachial and femoral pulses to search for the “brachial-femoral delay” of significant aortic coarctation. Supine bilateral arm (brachial artery) BP and prone right or left supine leg (popliteal artery) BP should be measured to search for differential pressures.
In pregnancy, increased blood volume and increased estrogen levels contribute to hypertension and increased shear stress on aortic wall; systemic hypertension is hence the most common risk associated with patients of coarctation, and is responsible for dilatation and dissection of the aorta. Poorly controlled hypertension also leads to adverse neonatal outcomes like growth retardation, abruption and premature delivery. Antihypertensive therapy can cause hypotension distal to the coarctation site, leading to reduction in uteroplacental perfusion.
In unrepaired coarctation, as also in repaired coarctation with arterial hypertension, residual coarctation, or aortic aneurysm, the risk to the fetus and mother is increased, and maternal mortality rate may be as high as 3-8%. Risk of aortic dissection, rupture of cerebral aneurysm, congestive heart failure and angina pectoris are increased in late pregnancy, intrapartum and within 6 weeks postpartum due to hemodynamic and hormonal changes.
Conservative management is preferred in antenatal period. Control of hypertension by beta-blockers, management of congestive cardiac failure by digoxin and afterload reduction by diuretics should be done as per individual case assessment. Indications for surgical intervention include significant coarctation or re-coarctation with long standing hypertension, hemodynamically significant aortic stenosis and female patient contemplating pregnancy.
Percutaneous intervention is possible during pregnancy. It should be performed only if there is persistence of severe resistant hypertension or presence of maternal compromise; as there is high chance of dissection during procedure. Surgical techniques include balloon dilatation with or without stent placement, patch aortoplasty with Dacron patch, and direct surgical repair with excision of the para-coarctation tissue.
LSCS was previously recommended due to greater risk of rupture of both aortic and cerebral artery aneurysms in late pregnancy, labor and early puerperium following vaginal delivery. However recent European Society of Cardiology (ESC) guidelines suggest vaginal delivery under epidural anesthesia is safe in both uncorrected and corrected coarctation.
To conclude, coarctation was fortunately but incidentally diagnosed when our patient was in labor. Value of measuring BP in different limbs cannot be over emphasised in every patient of hypertension. Contribution of physician, cardiologist and anesthetist was important in this case, and possibility of aortic dissection and subsequent mortality was averted.
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Dudhe M, Saxena N, Khadkikar R, Qureshi S, Chauhan AR. Near - Miss Mortality In Pregancy With Coarctation Of Aorta. JPGO 2014 Volume 1 Number 8. Available from: http://www.jpgo.org/2014/08/near-miss-mortality-in-pregancy-with.html