Percutaneous Transcatheter Implantable Gadgets for De Novo Aortic Valve Regurgitation After Left Ventricular Assist Device Implant: Pushing the Limits or a Feasible Bailout?

The number of new left ventricular assist device (LVAD) implants is constantly gathering pace.1 The introduction of rotary (continuous flow) LVADs and engineering developments in the recent decade has made long-term support possible.2 With 2 year survival rates approaching 70%,1 LVAD therapy is expanding far beyond its original bridging strategy to heart transplant.1,3,4 Hence, the majority of patients will be spending long times on the LVAD. Consequently, we will more frequently be challenged by long-term complications of LVAD therapy.5 This is especially true for one particular and unique complication associated with the alien LVAD physiology namely de novo aortic valve (AV) regurgitation (AR) which incidence is proportional to the duration of LVAD support.6 Currently, the freedom from moderate or greater AR is up to 94.7% ± 2.6% at 12 months, 86.9% ± 4.5% at 24 months, and 82.8% ± 5.9% at 36 months.7 While treatment of lesser grades of de novo AR after LVAD implant can be managed conservatively,8 moderate to severe AR leads to a vicious circle of recirculation and systemic low output6 that is not amendable to speed changes or medical therapy. This situation necessitates more aggressive treatment approaches to restore proper LVAD support. Treatment options for hemodynamically relevant AR in LVAD patients include surgical (bioprosthetic valve replacement, repair by creating a bileaflet valve or using central valve closure—Park Stitch—or total closure of the AV/left ventricular outflow tract) and percutaneous transcatheter (transcatheter AV replacement [TAVR] and occluder devices) procedures.8 However, not a single medical product has been tested to date, hence approved for use for addressing the AR in LVAD-supported patients and reports are anecdotal. While performing surgical correction of a native AR is straight forward, it is an unattractive and invasive procedure in the typically multimorbid patient cohort and associated with certain mortality. Therefore, percutaneous procedures to correct AR are extremely attractive given their low level of invasiveness. However, on a global scale next to nothing is known about the use of transcatheter devices in the VAD population. For this matter Phan et al.9 shall be commended for the elaborate work that provides us with a comprehensive review on the available data on this pioneering field. In the present study,9 both used device types show similar efficacy (first-/second-generation TAVR devices compared with septal occluder devices) in reducing the severity of AR but no real patient benefit. From those 29 patients that were intervened after a median of 14 months post-LVAD implant, 31% died before discharge. For all percutaneous devices the median survival time postintervention was 6 months. Device-related complications, including reintervention for device migration or insufficient result and fatal right heart failure, were common. These results are disappointing, underline the magnitude of the problem and should stimulate an intensive discussion on the usefulness and appropriateness TAVAR in LVAD patients with de novo AR and potential alternatives. Beyond doubt, the first- and second-generation TAVR systems used in the study were specifically designed to work in calcified and stenotic AVs and should therefore not be expected to work in LVAD patients with new onset AR and on to little valve calcification.10,11 This is underlined by the fact that suboptimal results with only partial resolution of AR and secondary interventions were frequent.9 In addition, a negative selection of patients is possible and patients were likely intervened late with already permanently damaged right ventricles. Nevertheless, an in-hospital mortality of 30% for in “imperfect” fix might justify the tradeoffs of a more invasive traditional surgical intervention, which permanently solves the problem. However, newer TAVR technology designed for pure AR12 might again change the entire situation. If percutaneous interventions should become standard in the treatment of hemodynamically relevant AR safety issues have to be considered. This goes beyond the “standard” and less life-threatening vascular complications and major bleeding.13 In parallel to conventional TAVR procedures, stroke is of major concern in LVAD patients. However, in contrary to calcific AV disease where embolization of atheromatous debris often underlies embolic events,13 aortic root thrombosis is intimately related with the altered LVAD physiology,14–16 might remain underdiagnosed and would be a contradictive for a transcatheter intervention. On a brief note, valve thrombosis might be inherent for some TAVR valves and might increase the risk of stroke.17 Again, long-term data are still cumulating. Next coronary ostial thrombosis might have been the reason for the fatal right ventricular failure observed in the study of Phan et al.9 And last but not least, AV closure completely discards the possibility of native residual cardiac output during physical activity or device failure which may restrict physical activity or prove fatal. Summarizing, de novo AR after LVAD implantation is a significant problem that affects 20% of patients after 24 months of support. Transcatheter AV implantation with the current devices is an imperfect solution that carries a 30% in-hospital mortality on top of a significant incidence of serious adverse events. New transcatheter devices designed for patients with pure AR might solve these problems. However, until these devices are available, a patients tailored approach should be perused, surgery considered, and transcatheter interventions should be limited to patients unfit for surgery or a “TAVAR friendly” AV anatomy.