Proportional pulmonary pulse pressure: A new index to assess response to veno-arterial extracorporeal membrane oxygenation.

ABSTRACT

BACKGROUND: Based on theoretical physiology, the ratio of pulmonary artery pulse pressure to mean pulmonary pressure (PP-MPAP), termed proportional pulmonary pulse pressure, provides a measure of coupling between the right ventricle and the pulmonary circulation. This study tested the hypothesis that lower PP-MPAP ratio was associated with left ventricular (LV) distension in patients with cardiogenic shock who underwent extracorporeal life support (ECLS). METHODS: This is a retrospective observational single-centre study of 22 patients with cardiogenic shock who underwent ECLS as the primary support modality without and with LV distension and Impella unloading. The relationship between post-support PP-MPAP and 12-hour lactate clearance was also assessed. RESULTS: Of the 22 patients 10 patients underwent additional Impella unloading due to LV distension (Group 1) and 12 patients on ECLS only without LV distension (Group 2). As predicted by the theoretical model, PP-MPAP on ECLS dropped in Group 1 (pre-Impella) from 0.473 ± 0.067 to 0.372 ± 0.087, p < 0.001; but increased in Group 2 patients without LV distension (0.518 ± 0.070 to 0.549 ± 0.072, p = 0.002). Impella support in Group 1 increased PP-MPAP (0.372 ± 0.087 to 0.615 ± 0.094, p < 0.001). On multiple regression analysis, post-support PP-MPAP was significantly associated with 12-hour lactate clearance. CONCLUSION: Changes in PP-MPAP is associated hemodynamic response to ECLS and 12-hour lactate clearance. This simple parameter may guide therapeutic optimization in cardiogenic shock and ECLS.