{'fraction_non_alphanumeric': 0.02383939774153074, 'fraction_numerical': 0.005771643663739021, 'mean_word_length': 5.1894409937888195, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Left Atrial Decompression by Percutaneous Left Atrial Venting Cannula Insertion during Venoarterial Extracorporeal Membrane Oxygenation Support

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
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 [1]. This can lead to left atrial (LA) hypertension and cause pulmonary edema. This serious problem can be resolved with LA decompression.
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. Thus, we decided to perform a percutaneous decompressive procedure. 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 [2]. 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 was admitted for fever, upper respiratory infection symptoms, and respiratory difficulty. 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. His condition rapidly declined shortly after admission. The patient was transferred to the intensive care unit with very poor he-  (Fig. 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. 3A), and endotracheal suction became creamy and watery. Four days later, we observed recovery of left ventricular function and improvement of the chest X-ray (Fig.   3B). These improved parameters allowed successful ECMO weaning. The total ECMO running time was 63 hours. The patient was transferred to a general ward 10 days after ECMO weaning. Follow-up echocardiography showed improved LV systolic function and an ejection fraction of 65%.

DISCUSSION
Since its introduction as a major support for severe respira- 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 [2]. However, balloon atrial septostomy alone is not always successful because of varying degrees of atrial septal thickness [9]. 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 [5]. Second, this procedure minimizes the risk of transseptal communication closure.
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.