– Expert Writer’s Comment – Key points in the diagnosis and management of aortic coarctation in pregnancy
Zhu Xianming
［Key］aortic coarctation; pregnancy; cardiovascular surgery; Department of Cardiovascular Surgery, Affiliated Hospital of Inner Mongolia Medical University, Zhu Xianming
［CCID］ R714.252 ［Reference Code］A ［Article Number]
Although the clinical morbidity of combined aortic coarctation in pregnancy is rare, it is more difficult to treat and manage, and remains a great challenge for cardiovascular surgery due to its aggressive onset, rapid development, high mortality rate, and safety of mother and child. In recent years, there has been a gradual increase in the number of related cases reported in China and abroad, and the surgical approach and the success rate of resuscitation have improved. The clinical features and management points of pregnancy combined with aortic coarctation are reviewed as follows.
Etiology and pathophysiological changes.
The incidence of aortic coarctation accounts for approximately 0.5–2.0/100,000 of the general population [1], and approximately 50% of aortic coarctations in young women develop during pregnancy, especially in the middle and late stages of pregnancy [2]. Pathophysiological changes: aortic coarctation begins when the endothelium and middle layer of the aortic wall tear to form an endothelial tear, which exposes the middle layer directly to the lumen, and blood flow in the aortic lumen, driven by high pressure, directly penetrates the diseased middle layer through the endothelial tear, separating the middle layer to form a coarctation. Various causes of aortic wall degeneration and intra-aortic luminal hemodynamic changes are responsible for the formation of aortic coarctation —————————————————————————————–
Author Affiliation : Department of Cardiac Macrovascular Surgery, Affiliated Hospital of Inner Mongolia Medical University, Hohhot, 010050, China
E-mail : [email protected]
endogenous and exogenous causes. For example: aortic valve diastasis, aortic constriction, aortic atherosclerosis, conjunctival histopathy, trauma, aortitis, Marfan’s syndrome, hypertensive disease, etc. It has been reported [3] that pregnancy is an independent risk factor for the development of aortic coarctation in young women, which may be related to changes in hormone levels and increased blood volume, cardiac output and blood pressure during pregnancy. Increased blood volume during pregnancy results in increased left ventricular output and increased impact of blood flow on the aortic wall. Estrogen inhibits the deposition of collagen and elastic fibers in the aortic wall, and progesterone promotes the deposition of non-collagenous proteins in the aortic wall, which decreases the elasticity and increases the fragility of the vessel wall [4] and easily causes the formation and rupture of aortic coarctation. 90% of gestational aortic coarctations are associated with hypertension or Marfan’S syndrome [5].
Clinical features.
Patients may present with sudden, unbearable tearing-like severe pain in the anterior thoracic region, scapular region, thoracic back, and epigastric region, and the use of analgesics such as morphine and dulcolax cannot achieve satisfactory pain relief. The pain site is wandering and radiating, suggesting that the aortic dissection is expanding. The absence of blood pressure drop in the presentation of painful shock is one of the main clinical features of the disease [6]. In a few cases, there is also no obvious severe pain in the chest and back, showing signs of ischemia of the corresponding organs such as chest tightness, shortness of breath, syncope, black haze, or anuria, lower limb numbness, and paraplegia caused by ischemia of the aortic branches. When the ascending aorta is involved, it may manifest as ascending aortic dilatation, aortic regurgitation, heart failure, and pericardial tamponade. In severe cases, death often occurs due to acute pericardial tamponade or rupture of the intercalated epicardium. Fetal intrauterine distress and fetal death in utero may occur due to insufficient placental ischemia and perfusion in the middle and late stages of pregnancy. In some cases, the pain is not severe and the clinical presentation is not specific, so it is usually easy to miss or misdiagnose. It has been reported that 85% of patients with aortic coarctation in mid- and late-pregnant women present with missed or misdiagnosed cases [7]. Pregnant women with a large abdominal burden and high negative pressure often have chest and back pain, and atypical pain is often misdiagnosed as stomach pain or pregnancy reaction, pregnancy subepilepsy, or gestational hypertensive disease. Even the cause of postpartum death is misdiagnosed as amniotic fluid embolism.
Diagnostic points.
According to the clinical presentation: 1. Sudden severe chest and back pain in patients with hypertension during pregnancy and requiring strong analgesics should be more alert to the possibility of entrapment. 2. Early cardiac macrovascular ultrasound is recommended in such cases. Its greatest advantage is that it is easy to perform, convenient and easy to use without affecting the fetus, it can be moved to the bedside, and it can be performed in patients with more severe or hemodynamically unstable clinically suspected acute aortic entrapment or Acute aortic syndrome in patients with severe or hemodynamically stable conditions [8]. Ultrasound can also evaluate both cardiac and valvular function and abnormalities. It shows direct signs such as widening of the aorta, dilatation of the ascending aorta, and echogenicity of torn endothelial sheets in the aortic lumen showing true and false lumen, endothelial rupture, and displacement of the calcified endothelial center. The accompanying signs are: aortic regurgitation, pericardial effusion, etc. Transesophageal echocardiography: examined after anesthesia in the operating room, it can clarify the extent of the lesion and provide a basis for the choice of surgical approach. 3. MRI and whole-body aortic CTA are more intuitive and clear diagnostic tools, both of which can show: endothelial slices, true and false lumen, endothelial rupture, branch involvement, pericardial and pleural effusion. However, X-rays and photographic agents can have adverse effects on the fetus and should be used with caution.
Treatment principles.
Depending on the clamping staging of each pregnant patient, a treatment plan individualized and different for each case is selected. For sudden acute type I aortic coarctation, aggressive surgical treatment is indicated regardless of the early or late stage of pregnancy. If the attending hospital is not equipped for cardiac surgery, it should be immediately transferred to a hospital with technical conditions for cardiac major vascular surgery. Surgical choice: cesarean section + total hysterectomy under general anesthesia [9, 10], followed by simultaneous aortic artificial vessel replacement under extracorporeal circulation. Depending on the condition and the location of the endothelial rupture of the aortic coarctation and the skill level of the surgeon, either simple replacement of the ascending aorta or total aortic arch + distal elephant trunk surgery (SUN’S surgery) can be chosen. The former operation is simpler, and is more suitable for those with heavy disease and aortic coarctation rupture in the ascending aorta. The operation time and extracorporeal circulation time are short, and the operation is simpler and safer to save the patient’s life first, and later, according to the recovery of the lesion, it can be operated again in the second stage.
For patients with intimal rupture in the arch of aortic coarctation or Marfan’s syndrome, SUN’S surgery is appropriate. The main points of surgical attention: extracorporeal circulation routine standby single pump double tube blood supply, right axillary artery insert donor vessel, right atrial second-step cannula drainage to establish extracorporeal circulation, operative field filling CO 2 , blocking the ascending aorta after cardiac arrest, continue cooling first deal with the proximal aorta, according to the aortic valve involvement, lesion regurgitation is mild can do forming to preserve, do artificial vessel ascending aorta proximal anastomosis, if the aortic root sinus, ring enlargement, the aortic valve regurgitation is severe and cannot be preserved, proximal treatment is appropriate with Bentall surgery. The nasopharyngeal temperature is lowered to 24°C and the anal temperature is 28°C. Methylprednisolone 15mg/kg is administered, the head is lowered at 30°, and the lower body is started to stop the extracorporeal circulation and selective unilateral cerebral perfusion is performed unilaterally via the right axillary artery supply with a flow rate of 5-10ml/kg/min. The distal ascending aorta is opened to explore the diseased vessel and the location of the endothelial rupture, and if there is no rupture in the arch and the vessel wall quality is good, simple If there is no rupture in the arch and the vessel wall quality is good, we can choose to do distal ascending aortic anastomosis or half arch anastomosis. If there is a rupture in the arch or if the head and arm trunk is severely involved, total arch replacement + distal stent vascular implantation (sun’s procedure) is performed. The aortic arch is incised longitudinally, the left subclavian artery is transected, and the proximal subclavian artery is sutured. The position of the distal anastomosis of the aortic arch can be raised forward to just before the opening of the left subclavian artery for easy exposure and convenient anastomosis. An island anastomosis of the arch can also be done if there is no significant involvement of the three cephalic vessels, which can reduce the number of three anastomoses, decrease bleeding, and save time.
At the end of lower body arrest circulation, full-flow extracorporeal circulation perfusion is restored by opening venous drainage after slow arterial return of blood, and rewarming is started after mixed venous oxygen saturation is greater than 80%, and artificial renal ultrafiltration is performed. After completion of the vascular anastomosis, the entire anastomosis is wrapped with the reserved ascending aortic epicardium + autologous pericardial piece and shunted with the right heart ear, which can effectively achieve hemostasis [11].
Patients with combined acute type A aortic coarctation during pregnancy are generally younger and have better cardiac function. If the treatment is timely and the surgical management is accurate, the survival of the baby at birth is largely unaffected. The outcome of the mother’s resuscitation is equivalent to that of a simple aortic coarctation case. Reports of successful cases have increased in recent years [2, 16].
For patients with acute Standford type B aortic coarctation, the early mortality rate is significantly lower than that of Standford type A [13], and medical conservative treatment combined with interventional endoluminal stent implantation can be used, with medical conservative treatment preferred in the acute phase, and after stabilization of the disease, depending on the expected date of delivery, overlapping stent implantation can be performed before delivery, or after delivery. In China, successful cases have been reported [14]. The early and intermediate results of endoluminal stent repair surgery with membrane in late pregnancy and puerperium for type B aortic coarctation are satisfactory, while the long-term results and stability need to be evaluated by a large sample size of clinical evidence.
It has been suggested that patients with aortic coarctation must use long-term effective contraception after marriage and contraindicate pregnancy [15], and if contraception fails, unintended pregnancy must be terminated by early abortion. Pregnancy should be avoided in the case of patients with Marfan syndrome. Active and effective control of gestational hypertension and treatment of the primary disease are effective methods to prevent aortic coarctation during pregnancy.
Although acute aortic coarctation in pregnancy is rare, the condition is dangerous and progresses rapidly, and should be diagnosed as early as possible. Choosing an appropriate individualized treatment plan according to the condition of the mother and the baby and the type of coarctation is the key to save the life of the patient and the fetus.
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