a problem that has frequently emerged as a critical issue in patients with venoarterial ( va ) extracorporeal membranous oxygenation ( ecmo ) is a dilatation of the left heart due to volume overload of the left ventricle .
conventionally , a venting cannula is placed in the left atrium via the right upper pulmonary vein or the la auricle with a sternotomy or a lateral thoracotomy . however , these approaches are risky because of significant complications such as bleeding and scarring .
the procedure chosen for percutaneous left heart decompression varies from insertion of the la venting cannula to placement of an atrial septal stent .
recent reports showed that there was no significant difference between these procedures . here , we describe a successful percutaneous balloon atrial septostomy and an la venting cannula insertion during va ecmo in a patient with severe acute myocarditis . a 38-month - old , 11.7 kg boy
he had suffered from intraventricular hemorrhage and intracranial hemorrhage caused by neonatal asphyxia , and he had been kept on antiepileptic medication due to infantile spasm .
the patient was transferred to the intensive care unit with very poor hemodynamics and subsequent supraventricular tachycardia ( heart rate > 200/min ) , which did not respond to intravenous amiodarone or adenosine . despite conventional therapy including inotropes , his condition continued to deteriorate with tachycardia .
echocardiography revealed a marked decrease of 20% in the ejection fraction , and we therefore decided to support him with va ecmo .
arterial cannulation was performed via the right carotid artery with an 8 fr percutaneous arterial cannula ( rmi ; edwards lifesciences , irvine , ca , usa ) , and a 14 fr percutaneous venous cannula ( rmi , edwards lifesciences ) was placed in the right internal jugular vein .
ecmo flow was initially 1,300 ml / min and was maintained between 700 to 800 ml / min .
after ecmo insertion , the patient s vital signs stabilized and his chest x - ray improved ( fig .
however , he began to produce a large amount of frothy , bloody endotracheal secretions and his pulse pressure disappeared twelve hours later .
follow - up echocardiography revealed marked left heart distention and a left ventricular ejection fraction lower than 10% . therefore ,
fourteen hours after ecmo insertion , the patient was taken to the cardiac catheter laboratory for an atrial balloon septostomy and la venting cannula insertion .
the procedure was accomplished with a percutaneous approach through the right femoral vein without complications and an 8.5 fr la venting cannula ( mullins sheath ; cook inc .
2 ) . after placement of the la venting cannula , the pulse pressure appeared again , with a 15 mmhg gap between the systolic and diastolic pressure . his follow - up chest x - ray improved ( fig .
four days later , we observed recovery of left ventricular function and improvement of the chest x - ray ( fig .
follow - up echocardiography showed improved lv systolic function and an ejection fraction of 65% .
since its introduction as a major support for severe respiratory distress , ecmo has become a well - established therapy in pediatric patients , particularly those with severe but reversible neonatal respiratory failure , cardiac failure , or cardiorespiratory failure . in particular , va ecmo has been used in pediatric patients with cardiac dysfunction , such as myocarditis , cardiac arrest , and cardiomyopathy . left heart distension during va ecmo may develop , leading to progressive left heart deterioration , pulmonary edema , and impairment of myocardial oxygenation . despite its clinical importance , the management of left heart decompression in a patient with ecmo is rarely discussed .
only sporadic case reports and a few articles have shown the efficacy of la decompression on functional recovery of the left heart [ 57 ] .
conventionally , la decompression is achieved by insertion of an la venting cannula via sternotomy or thoracotomy
. however , sternotomy or thoracotomy themselves are risky and have several complications , such as bleeding and significant scarring .
la decompression with a percutaneous cardiac catheterization - based technique including septostomy using a blade or radiofrequency ablation , balloon dilatation , and la venting cannula insertion has been effective [ 2,46,8 ] .
several institutions with la vents have identified technical issues related to management of the indwelling catheters , such as kinking , poor flow , movement of the catheter with required patient care , and ongoing concern for thrombosis .
therefore , a recent study showed a shift in preference from la vent insertion to balloon dilation alone . however , balloon atrial septostomy alone is not always successful because of varying degrees of atrial septal thickness .
we believe that using an la venting cannula after balloon dilation offers several advantages over balloon dilatation alone .
first , the placement of an la venting cannula potentially allows for controlled decompression of the left heart by adjusting flow rates on the ecmo circuit or clamping the cannula .
third , the size of the cannula can be tailored to each patient , so this procedure can be adjusted for use in smaller patients . for patients with left heart dysfunction causing pulmonary edema during va ecmo , percutaneous balloon atrial septostomy with la venting cannula insertion is a treatment option that carries a low risk of other complications such as bleeding .
 patients with venoarterial extracorporeal membrane oxygenation ( ecmo ) frequently suffer from pulmonary edema due to left ventricular dysfunction that accompanies left heart dilatation , which is caused by left atrial hypertension . 
 the problem can be resolved by left atrium ( la ) decompression . 
 we performed a successful percutaneous la decompression with an atrial septostomy and placement of an la venting cannula in a 38-month - old child treated with venoarterial ecmo for acute myocarditis . 
CASE REPORT
DISCUSSION