Postoperative left ventricular function in different types of pulmonary hypertension: a comparative study

Left ventricular dysfunction after pulmonary endarterectomy is well described. Left ventricular failure has only been described after lung transplantation for pulmonary arterial hypertension (PAH). We sought to identify factors that contribute to this failure and hypothesized that atrial septostomy before transplantation could prevent this complication.

From our database, all bilateral lung transplants for PAH (n = 24) and all pulmonary endarterectomies, with a minimal reduction of 800 dyn⋅s⋅cm-5 (n = 27), were selected. Perioperative demographic and echocardiographic data were analysed.

In patients with PAH, pulmonary hypertension was diagnosed at a significantly younger age, and time between diagnosis and surgery was significantly longer. Before surgery, right ventricular dimensions were significantly larger and left ventricular wall thicknesses were significantly smaller, but left ventricular diastolic dysfunction was similar. Surgery caused a significant decrease in right ventricular dimensions (less extensive after pulmonary endarterectomy) and caused a significant increase in left ventricular dimensions. Pre-transplant atrial septostomy caused increased left ventricular dimensions, stroke volume and cardiac index. Two patients developed post-transplant left ventricular failure. Compared with other PAH patients, they were younger (<12 years) at diagnosis, time between diagnosis and surgery lasted 2.5 times longer, left ventricular mass was smaller and pre-transplant pulmonary vascular resistance was higher.

In PAH, age at diagnosis is younger and left ventricular preload deprivation lasts longer than that in chronic thromboembolic pulmonary hypertension. Together with lower residual pulmonary vascular resistance and higher increases in preload, this might explain left ventricular failure after lung transplantation. Pre-transplant atrial septostomy might prevent post-transplant left ventricular failure.