Aortic balloon valvuloplasty and severe systolic dysfunction. Is there a danger zone

In 1986, Cribier et al. attempted the first percutane-ous transluminal balloon aortic valvuloplasty (BAV) inthree elderly patients with severe symptomatic aorticstenosis [1]. This was followed by a number of largerstudies that showed low early mortality after BAV, buthigh rates of late restenosis without changing the natu-ral history of aortic stenosis. Between 1988 and 1994,outcomes for palliative BAV were reported [2,3]. Morethan half of the late cardiac deaths were found inpatients with reduced left ventricular ejection fraction(LVEF) and extensive coronary artery disease. Duringthe subsequent decade, the procedure was almost aban-doned and only indicated as a bridge to surgical aorticvalve replacement (SAVR). After the inception oftranscatheter valve therapies for high-risk and inoper-able patients, the use of BAV increased steadily, withimproved procedural outcomes, especially when per-formed by experienced operators. Even though BAV isassociated with higher complication rates in extremerisk patients with severe systolic dysfunction, these arethe patients most likely to derive the greatest benefitthrough improved functional capacity, left ventricularfunction recovery, and a reduction in the severity ofconcomitant mitral regurgitation.In this issue, Pedersen et al. described the outcomesof 16 extreme-risk patients with low LVEF (<20%)and median society of thoracic surgery score of 16.4who underwent BAV, representing only 6% of the pro-cedures performed at their center between 2005 and2010, when transcatheter aortic valve replacement(TAVR) was only available in the setting of clinicaltrials that excluded patients with LVEF<20% [4]. Inthis series, BAV was performed using standard retro-grade technique with noncompliant balloons underrapid pacing aiming to reduce the peak gradient by50%. Their results were encouraging without majorintraprocedural adverse events or immediate postopera-tive mortality. Of note, none of the procedures wereelectively supported by percutaneous left ventricularassist devices. However, more than half of the patientsreceived inotropes, two patients required intra-aorticballoon pump as bail-out for severe hemodynamicinstability, and two patients underwent concomitantpercutaneous revascularization. Approximately half ofthe patients experienced LVEF improvement after theprocedure. Factors associated with improved LVEFincluded absence of significant coronary artery diseaseand the absolute increase in aortic valve area. Eventhough, in-hospital outcomes were relatively favorableconsidering the high risk of the studied population,71% of patients were dead at 1-year, confirming thefact that BAV is a palliative procedure that does notalter the deadly course of aortic stenosis.Despite the small sample size, there are importantobservations in this study. First, hemodynamic decom-pensation during or immediately after BAV proceduresis not infrequent. Patients with severe AS and concom-itant systolic dysfunction have impaired myocardialreserve, thus, hemodynamic instability and cardiacdepression can develop after rapid ventricular pacing.In addition to inotropes, operators may consider elec-tive use of percutaneous left ventricular assist devicesin extremely high-risk cases. A previous study demon-strated that BAV assisted by a microaxial flow pump(Impella 2.5; Abiomed, Danvers, MA) can be success-fully performed to protect the left ventricle from theacute increase in afterload during systole against anocclusive balloon [5]. Second, identifying patients whowill experience LV reverse remodeling after BAV orTAVR is challenging. The absence of fixed myocardial