Beyond the Valve: Ventricular Resilience as a Survival Predictor in TAVR for Pure Aortic Regurgitation

In the article published in this issue of Echocardiography, Liu and colleagues present a fascinating and clinically relevant retrospective analysis titled “Association of Early Left Ventricular Ejection Fraction Patterns With Functional Recovery and Outcomes After Transcatheter Aortic Valve Replacement for Pure Aortic Regurgitation” [1]. The study addresses a phenomenon frequently observed in clinical practice but rarely codified: the acute drop in left ventricular ejection fraction (LVEF) immediately post-procedure and, crucially, the trajectory of recovery over the subsequent month. Pure aortic regurgitation (AR) represents one of the most complex challenges in the modern era of interventional cardiology. Although the burden of valvular heart disease increases with the aging population [2], and transcatheter aortic valve replacement (TAVR) has become the standard of care for aortic stenosis (AS), its use in pure AR remains largely limited to selected high-risk patients [3]. Anatomical challenges—primarily the absence of leaflets calcification to anchor the device—have historically hindered the use of transcatheter heart valves (THV) designed for AS (off-label use in pure AR) [4, 5]. However, with the advent of new-generation devices, clinical focus is shifting from technical feasibility to the physiological response of the left ventricle (LV) following defect correction. The heart affected by chronic AR is an organ that has undergone profound remodeling. Massive volume overload induces eccentric dilation and compensatory hypertrophy which, for years, maintain adequate stroke volume despite the regurgitation [6]. An initial LV maladaptative process can be echographically masked by a pronounced Frank–Starling mechanism. When we perform TAVR, we abruptly eliminate the regurgitation. While this is the therapeutic goal, the ventricle is suddenly forced to pump against real systemic impedance without the “relief valve” of low-pressure diastolic runoff. Liu et al. report that a striking 55.90% of their patients with pure AR undergoing TAVR experienced an acute reduction in LVEF (≥5%) at discharge [1]. This figure is significantly higher than that observed in the AS population, where this phenomenon occurs in approximately 25% of cases and is often transient [7]. This suggests that the ventricle in pure AR is particularly vulnerable to acute alterations in hemodynamic load. The crucial contribution of this study lies not merely in identifying the drop, but in categorizing patients based on their short-term recovery capacity. The authors identified two distinct phenotypes based on LVEF change at 1 month: the “Rebound” pattern, characterized by an LVEF recovery of more than 10%, and the “Decliner” pattern, where such recovery is absent [1]. The results are striking: the “Rebound” group (comprising 54.69% of the initial drop cohort) not only normalized systolic function at 1 year but demonstrated significantly superior freedom from major adverse cardiovascular events (MACE) compared to “Decliners” [1]. In multivariable analysis, the early recovery pattern emerged as an independent protective factor for MACE and mortality. These data align with previous observations in traditional surgery (SAVR), where early recovery of ventricular function has been associated with better long-term survival [8]. It is plausible, as hypothesized by the authors, that the “Rebound” group represents the classic phenomenon of transient afterload mismatch. In these patients, the ventricle is “stunned” by the sudden increase in systolic wall stress but still possesses sufficient contractile reserve to adapt and remodel positively once the acute phase is overcome [1, 9]. Conversely, the “Decliner” pattern is a red flag. It suggests that the ventricle has exhausted its compensatory mechanisms. Chronic dilation and wall stress have likely led to irreversible interstitial fibrosis, rendering the myocardium incapable of handling the new hemodynamic conditions [10]. Cardiac magnetic resonance (CMR) studies have shown that the presence of replacement fibrosis in AR is a powerful negative predictor of functional recovery [11]. Notably, the “Decliners” in the study by Liu et al. had a higher percentage of NYHA class IV status at 1 year [1], confirming that hemodynamic damage translates into clinical failure. The study by Liu et al. offers a simple and cost-effective tool for risk stratification: the 1-month echocardiogram. In daily clinical practice, we often focus on valvular gradients or paravalvular leaks during follow-up. This study invites us to shift our attention to the trajectory of ventricular function. Identifying a patient as a “Decliner” at 30 days should trigger a shift in clinical management: close follow-up (strict monitoring, extending well beyond current standards); pharmacological optimization (early introduction of guideline-directed medical therapy for heart failure, potentially including beta-blockers and SGLT2 inhibitors, could be crucial to support a ventricle failing to achieve reverse remodeling); reflection on timing (intervention based on symptom onset or resting LVEF decline) [11, 12]. However, Liu's data suggest that for some patients (“Decliners”), intervention may have arrived too late, when fibrosis was already irreversible, despite an apparently acceptable baseline LVEF. Despite the importance of the results, the study has intrinsic limitations. A significant limitation, common to many AR studies, is the use of LVEF alone as a parameter of systolic function [1]. The future of research in this field could include the analysis of global longitudinal strain (GLS) and, ideally, CMR to quantify myocardial fibrosis. It would be fascinating to verify if pre-procedural fibrosis on CMR correlates with the post-TAVR “Decliner” phenotype, confirming the mechanistic hypothesis proposed by Liu and colleagues [1]. Only a small percentage of patients received the only approved THV for AR (JenaValve trilogy), resulting in a not negligible incidence of VARC-3 technical unsuccess (mainly driven by the frequent need of a second THV) [13]. Moreover, the relevant need of post-TAVI permanent pacemaker and the numerically higher rate of moderate paravalvular regurgitation in the decliner pattern may have played an independent detrimental role on MACE occurrence [14]. Furthermore, although the results are promising, the thresholds for “Decline” (≥5%) and “Recovery” (≥10%) of LVEF derived from this cohort require external validation in larger, multicenter populations [1]. The article by Liu et al. represents a significant step forward in our understanding of TAVR for pure AR. It shifts the focus from valve implantation to the ventricle-prosthesis interaction over time. The message for the clinical cardiologist is clear: a drop in cardiac function at discharge is common, but what happens in the subsequent month defines the patient's destiny. The “Rebound” phenotype is proof of the heart's resilience; the “Decliner” phenotype is a cry for help requiring immediate therapeutic action.