I'm trying to find studies on the use of one of the new mechanical
heart pumps, aka Left Ventricular Assist Devices (LVAD), that are
provided to patients waiting for a heart transplant. I'm not
interested in case studies but in randomized trials, with some kind of
placebo and with a large number of patients (30+).

I haven't been able to find any studies on the new devices using
impeller pumps (Debakey, Jarvik 2K, etc.), which is really what I'm
looking for... I'm not sure any have been done, I've only found very
limited trials and case studies. I'm also looking for results of
randomized trials of pulsatile devices used for bridge to
transplantation (e.g. heartmate).

In the answer, I would like citations to the articles (at least 2,
preferably more) containing the information I'm looking for, with the
abstract for each if possible. I want to specify that I'm looking for
significant statistical clinical data, preferably randomized, *not*
qualitative stuff.