1. Introduction
Despite improvements in patient selection and management algorithms, right ventricular failure (RVF) remains as a major cause of postoperative morbidity and mortality following left ventricular assist device (LVAD) implantation and seen in up to 13% - 51% of patients, depending on the definition of RVF (1,2). Several clinical, imaging, laboratory and catheterization parameters are available to predict postoperative RVF with variable diagnostic accuracy (3). Of those, transthoracic echocardiography (TTE) plays a pivotal role for preoperative evaluation of the right ventricle (RV) as this is a widely available modality that could be easily utilized at bedside and it allows a comprehensive evaluation for the structural and functional alterations in the RV (3). Numerous echocardiographic parameters were studied as a possible “gold-standard” method to predict post-LVAD RVF, though these variables rarely performed well beyond their initial study cohort. A recent meta-analysis that included available echocardiographic parameters has concluded that a qualitative analysis of the RV remains as the best predictor of postoperative outcomes (3).
A major shortcoming of all available standalone parameters is that the variable in question either evaluates structural (i.e. RV diameter or RV to left ventricle (LV) ratio) or hemodynamic / functional (tricuspid annular excursion, pulmonary artery pressure) changes in the RV. As a result, other aspects of the RV structure or function is omitted and therefore the parameter studied does not fully reflect alterations in the RV. As such, an index that combines both structural and hemodynamic/functional changes in the RV could theoretically be more useful over existing parameters to predict post-LVAD RVF.
In the present analysis, we aimed to investigate the usefulness of RV pressure-dimension index (PDI), a novel index that reflects both the structural and functional changes in the RV, to predict post-LVAD short-term and long-term mortality and RV failure. In addition, correlation of PDI with available parameters of RV structure and function was also investigated.