Mortality after radial-only balloon aortic valvuloplasty: a long-term follow-up and a bridge-to-TAVI analysis

Recently, the DR-BAV (Distal Radial – Balloon Aortic Valvuloplasty) pilot study demonstrated the feasibility of performing balloon aortic valvuloplasty (BAV) through an exclusively distal radial access (DRA), reaching the efficacy endpoint (decrease in maximum and mean aortic gradient from 73 ± 22 mm Hg and 49 ± 22 mm Hg to 49 ± 19 mm Hg and 20 ± 13 mm Hg, respectively; P < 0.001) and reporting zero vascular complications as well as zero periprocedural major cardiovascular events [1]. Of course, a longer-term follow-up of these patients would bring more information, especially since half of the patients in this cohort received “emergency” BAV as primary indication and others were scheduled for transcatheter aortic valve implantation (TAVI), the baseline procedure being considered only stabilizing or life-saving. The radial approach in this context proved valuable, preserving the femoral approach that may be needed in the future [1]. For BAV, large sheaths are needed, which can injure the arterial wall—a vulnerable structure in this category of patients. Thus, puncturing the radial artery at the anatomical snuffbox level to perform BAV should not be perceived as a radialist “eccentricity” but a worthwhile practice to preserve the radial artery (one of the major advantages of DRA having less radial artery occlusion rates) and for use as a secondary arterial access for TAVI [2].

After a median follow-up duration of 24 months, we conducted a retrospective evaluation of the clinical course of these patients. Furthermore, we categorized the cohort into individuals who underwent TAVI and those who did not, with the objective of examining whether this supplementary procedure influenced mortality. It is already known that BAV as an isolated intervention is inferior to TAVI and should only be indicated as a bridging intervention [3,4,5], although recently it has also gained interest as a palliative measure in many centers [6,7]. However, within the realm of cardiovascular medicine, the term “palliative” carries a more subjective and nuanced meaning compared to its usage in oncology. For instance, octogenarians and frail patients may experience a significantly enhanced clinical progression following such an intervention. The aim of this study was to analyze patients with a history of primary BAV, with or without secondary TAVI, in terms of hard clinical endpoints during a long-term follow-up (two years), starting from the initial distal radial BAV procedure.

In the present study, we could show that half of the patients undergoing BAV eventually need TAVI, most of them within 5 months after BAV, and that BAV remains associated with high mortality after the procedure, with 5 out of 14 of those undergoing isolated BAV dying during short-term follow-up. Figure 2 illustrates that eventually > 60% of patients undergoing BAV eventually die or need a TAVI procedure.

This remains consistent with other reported data [9–12]. Most of our patients received TAVI in the first three to four months, an interval which is similar with other reported national registries [12]. In a larger study exploring the role of BAV in critically ill patients, Kumar et al. delineated three groups of patients: critically ill on the intensive care unit (ICU), ward, and outpatient. The unadjusted 1-year mortality was high and increased stepwise between the three groups of patients (28.9%, 44.1%, 67.6%, p < 0.001 for the outpatient, inpatient ward, and ICU group, respectively) [13]. Conversely, the 1-year mortality in the subset of patients who underwent TAVI after BAV was similar within the three groups and was low (<18%) given the severity of the patients’ illness. The research team highlighted the positive outcomes for ICU patients treated with TAVI as proof of BAV’s important function in triaging patients who may benefit from the therapy. The dramatic mortality (93.3% at 1-year) among patients of the ICU group who did not undergo TAVI speaks in favor of BAV conveying favorable outcomes only when followed by TAVI [13]. This raises concerns about the viability of providing TAVI to a larger number of patients, as well as the best timing for interventions (BAV or TAVI). In this context, the radial-only BAV presents a minimally invasive method that preserves the femoral artery and could be very useful in some clinical scenarios such as stabilizing heart failure episodes or facilitating recovery or treating non-cardiac conditions before TAVI. Certainly, patients who would derive benefits from TAVI should indeed undergo the procedure. However, in the case of severely ill patients, determining their suitability for TAVI can be challenging, and the BAV procedure does not add complexity to this decision; on the contrary, it aids in the decision-making process.

While TAVI has evolved into a more angioplasty-like routine procedure (without the presence of the anesthesia team in the operating room) that provides superior hemodynamic efficacy over BAV [14], BAV does retain some benefits. It is less expensive and more generally available, does not require contrast injection or preprocedural imagistic evaluation, can be performed with smaller sheath sizes and radial access, and can be conducted in patients who have an interim contraindication to prosthesis implantation (e.g., sepsis) [15]. In the simplest terms, BAV is currently mostly utilized as a triage tool in frail or severely ill patients when clinicians are concerned that a TAVI operation might be ineffective. Following the BAV, either the patient’s condition improves and they become a candidate for TAVI, or the patient’s condition worsens and a futile TAVI has been avoided. The opposing argument is that BAV-bridging strategy might lead to a delayed TAVI and could be associated with a loss of opportunity for the sickest patients. Apparently, there are no differences in outcomes between TAVI and non-TAVI centers and BAV can be performed safely even in centers without surgical back-up if the operator is experienced and has been trained in TAVI centers [16].

The palliation concept remains a pragmatic triage and treatment method. In this setting, the radial approach can keep the patient hospitalized as briefly as possible. For the frail patients with associated peripheral arterial disease that contraindicates femoral TAVI, “radial palliation” generates a contemporary indication. For femoral access, it has been recently shown that BAV may in fact be performed without heparin administration and that this resulted in fewer vascular complications [17].

Quality of life in BAV patients compares very favorably with conservatively managed patients at 6 months, while the benefit of BAV as a standalone procedure has been reported to be lost by 12 months follow-up [18,19]. The importance of symptom relief in a population with limited life expectancy due to frailty, old age, and numerous comorbidities cannot be underestimated. It should be acknowledged that BAV is a temporary treatment that reduces the need for recurring hospitalizations. BAV also proved valuable in the coronavirus disease 2019 pandemic, representing a viable therapeutic option in patients with suspected or confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [20].

One of the main study’s limitations was the small sample size of the study population which did not allow us to generate Kaplan-Meier survival curves and draw definitive conclusions on mortality between the BAV-only group and the BAV + TAVI group. The current study’s patient population was insufficient to definitively analyze mortality as an endpoint. We also did not include in the analysis other hard clinical endpoints such as myocardial infarction or hospitalizations for acute heart failure. Lastly, the clinical progression regarding restenosis and negative clinical outcomes in patients with symptomatic severe aortic stenosis who undergo BAV as a standalone procedure is not groundbreaking, but it aligns with previous findings. The advantages derived from TAVI as the ultimate treatment are also thoroughly documented and supported by a significant body of evidence.

In the current study, the mortality at two years after radial-only balloon aortic valvuloplasty remains high, being mainly driven by the patient’s age, comorbidities, and the lack of TAVI.