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Percutaneous left ventricular assist device support during ablation of ventricular tachycardia: A meta‐analysis of current evidence

To the Editor, We read the article by Dr Luni and colleagues with interest. This meta‐analysis (MA) compared clinical outcomes of patients who underwent ventricular tachycardia (VT) ablation with percutaneous ventricular assist device (PLVAD) support with controls (no‐ PLVAD). After pooling data from nine observational studies, the authors concluded that there was no significant difference in mortality, acute procedural success or VT recurrence between both groups. However, the use of PLVAD was associated with longer procedure time and higher complications compared with no‐PLVAD. We wanted to point out several concerns with this manuscript that we feel negatively impacts the validity of the results as well as potential clinical implications. First, the MA does not include studies that are representative of the exposed cohort. In the absence of head‐to‐head trials, the authors attempt to perform an indirect comparison between PLVAD and controls by including both true controls (no‐hemodynamic support) and those who received an intra‐aortic balloon pump (IABP). Among the nine included studies, Aryana et al compared PLVAD (n = 230) with IABP (n = 115), Reddy et al compared IABP (n = 22) with Impella/TandemHeart (n = 44), and Miller et al compared PLVAD (n = 10) with IABP (n = 6)/controls (n = 7). In addition, the PLVAD group included a myriad of different mechanical circulatory devices, such as Impella 2.5/CP/5.0, TandemHeart, and extracorporeal membrane oxygenation that offer various levels of hemodynamic support and cannot be considered to be a one‐ size‐fits‐all option (Table 1). Performing an MA of observational, non‐randomized studies with substantial differences in the type of intervention received leads to significant selection‐bias and raises serious questions regarding the methodology and the validity of the study results. Second, we also wonder if the lack of difference in baseline characteristics between the PLVAD and the no‐PLVAD group is due to the inclusion of patients with IABP in the control arm who may be a “higher‐risk” group of patients compared with pure controls. Finally, this MA of PLVAD support during VT ablation is based on assumptions, results are mainly driven by one study that includes greater than 80% of patients and should be judged to be of low quality due to marked heterogeneity and serious risk of bias.