Aortic coarctation
is a tear in the intima of the aorta that causes blood to flow through a rupture in the intima and form an intercalated hematoma between the layers of the aortic wall, forcing the layers of the aortic wall apart. It is a dangerous, acute condition that can be rapidly fatal. If the aortic coarctation is completely torn, there will be rapid massive blood loss leading to circulatory collapse and immediate death. The mortality rate of aortic dissection is 80%, and 50% die before they even reach the hospital. Therefore, if the aortic coarctation reaches 6 cm, the patient must be treated with emergency surgery.
Staging
DeBakey staging
Type I – Thoracic aortic coarctation originates in the ascending aorta and extends distally, involving at least the aortic arch;
Type II – Thoracic aortic coarctation originates and is confined to the ascending aorta;
Type III – thoracic aortic coarctation originates in the descending aorta and rarely extends proximally, but may involve the distal end of the vessel. Those that do not involve the abdominal aorta downward are called type IIIA, and those that do are called type IIIB.
Stanford typing
Type A – Aortic coarctation involving the ascending aorta and/or aortic arch, with possible involvement of the descending aorta. The intimal tear originates in the ascending aorta, the aortic arch, or the descending aorta (less common). This subtype is equivalent to DeBakey
type I, DeBakey type II, and retrograde DeBakey type III (aortic coarctation originating in the descending aorta and extending proximally to involve the ascending aorta);
Type B – Aortic coarctation involving the descending aorta and/or extending into the abdominal aorta, but not involving the ascending aorta and aortic arch. This staging corresponds to cases in which DeBakey type III does not involve the ascending aorta retrogradely.
Signs and Symptoms
About 96% of patients with aortic coarctation have a sudden onset of severe tearing pain, which is the most prominent and characteristic symptom of the disease.
Less common signs and symptoms of aortic coarctation include: congestive heart failure (7%), syncope (9%), cerebrovascular accident (3-6%), ischemic peripheral neuropathy, paralysis, cardiac arrest, and sudden death. If an individual has a syncopal episode, half of them may be due to a pericardial tamponade caused by an external rupture of blood from the aortic coarctation into the pericardium. Neurological complications of aortic coarctation (i.e., cerebrovascular accident and paralysis) are due to one or more arteries supplying the central nervous system being involved by aortic coarctation. If aortic coarctation involves the abdominal aorta, extension to the mesenteric artery can cause acute abdominal necrosis in 3-5% of patients with abdominal aortic coarctation, while extension to the renal artery can cause acute low back pain, hematuria, acute renal failure, or renal hypertension in 58% of cases.
Diagnosis
Chest X-ray plain film
mainly widening of mediastinal shadow and marked widening of aortic window
CT examination
CT is the gold standard for clarifying aortic coarctation. By applying contrast agent, the true and false lumen of coarctation can be distinguished, which is of clinical guidance.
Treatment
Drug treatment
Aortic coarctation usually presents as a hypertensive emergency, so the primary consideration of medical treatment is to strictly control blood pressure. The goal of blood pressure control is a mean arterial pressure of 60 to 75 mm Hg, or the lowest blood pressure that the patient can tolerate. Another factor is to reduce left ventricular dp/dt shear (the force of the left ventricular ejection into the ascending aorta).
Beta-blockers are the first-line agents in the treatment of acute and chronic aortic coarctation. In patients with acute aortic coarctation, rapidly administered intravenous drugs (e.g., esmolol, propranolol, labetalol, etc.) are preferred. Vasodilators, such as sodium nitroprusside, can be used in patients with persistent hypertension, but these drugs should not be used alone because they usually cause reflex tachycardia.
Calcium channel blockers can also be used to treat aortic coarctation, especially if there are contraindications to beta-blockers. The most commonly used calcium channel blockers are verapamil and diltiazem, because of their combined vasodilatory and muscle-weakening effects.
In case of individual intractable hypertension (persistent hypertension despite treatment with three different classes of maximal doses of antihypertensive drugs), the involvement of the aortic coarctation in the renal arteries leading to renal hypertension must be considered.
Surgical treatment
is the only effective treatment for aortic coarctation. Depending on the fractal shape of the aortic coarctation and the extent of the lesion, different surgical approaches are chosen. The surgical approaches are: David’s procedure, Bentall’s procedure, Carbrol’s procedure, Wheats’ procedure + half arch or full arch + distal elephant trunk procedure.
Prognosis
The long term outcome after surgery is excellent. There are follow-up reports of patients surviving for more than 15 years without problems.