The aetiology of paediatric acute cardiogenic shock (CS) varies more than that in adults, and may include coronary artery disease, myocarditis, congenital heart disease, cardiomyopathy, diastolic heart failure and systolic heart failure. Unlike in adults, ischaemic coronary artery disease is not a common CS aetiology in children. Paediatric CS patients often possess a single ventricle, or have undergone a Fontan procedure or biventricular repair. Treatment options are limited by smaller patient size, reduced ventricular dimensions and lack of mechanical support devices approved for use in children. Percutaneous circulatory support options, such as balloon pumps, may enable haemodynamic support for adults, but are often more harmful in children.
Left ventricular (LV) unloading is necessary to decrease ventricular size and pressure in paediatric CS patients. The standard LV unloading approach at many centres is static balloon atrial dilation of the septum, balloon atrial septostomy, stenting the atrial septum or left atrial venting with extracorporeal membrane oxygenation (ECMO) support. ECMO is often used due to ease of access and rapid oxygenation of the blood; however, lack of optimal coronary reperfusion compromises long-term patient recovery. After ECMO placement, immediate echocardiogram imaging to assess canula position and ventricular ejection status can help determine whether additional LV unloading is required.
The panellists recommend additional haemodynamic support modalities, such as the Impella transvalvular pump, to achieve LV unloading. The panellists discussed specific patients, in which the Impella 5.5, used in combination with ECMO, improved recovery in ischaemic CS patients by decreasing LV end-diastolic pressure. The Impella device provides greater ease of placement, acute decompression and a bridge to weaning the patient off ECMO, reducing ECMO-associated morbidity. Discussion also focused on the utilisation of LV unloading, followed by right ventricular support prior to resorting to ECMO in paediatric CS patients. Dr Adachi and Dr Morray further discussed using Impella-mediated LV unloading for single-ventricle paediatric CS patients with failed Fontan circulation, as it decreases central venous pressure, improves cardiac output and increases survival.
A multidisciplinary approach to assess paediatric CS patients ensures selection of the least invasive and most effective surgical techniques and LV unloading method. Determination of CS aetiology by monitoring the (lack of) response to therapies, biventricular dysfunction, chronicity of heart failure and lactate levels can assist with appropriate device selection. Vascular access techniques, such as hybrid access and trans-cable access, together with reduced sheath and catheter size, can decrease surgical complications. Timing of placement and removal of mechanical support devices should be optimised. Physician collaboration with industry partners is critical to driving development of paediatric-specific mechanical unloading devices.