The rapid evolution of TAVI has encountered certain challenges, spurred by independent and responsible publications that, in my view, are beginning to define the role of this excellent therapeutic alternative within increasingly specific indications. To date, TAVI’s proliferation has largely depended on an accelerated expansion of indications, recently bolstered by: (1) the shift from surgical risk criteria to age as a determinant, once non-inferiority at low and moderate risk was demonstrated; (2) research extensions toward asymptomatic aortic stenosis profiles; and (3) treatment strategies targeting increasingly younger patients, where the simple recommendation for bioprosthetic valve implantation opens the door for TAVI, despite the probable need for future re-interventions that may still require surgery. This scenario unfolds as TAVI durability remains uncertain, and findings reveal that this transcatheter approach is not free from complications impacting patient survival and quality of life, rendering it more invasive than initially perceived. Examples include conduction disturbances requiring pacemaker implantation, thromboembolic events from the neosinuses, and restricted coronary bed access.

Successive generations of TAVI devices have aimed to address paravalvular leak, a complication resulting from implantation within the pathological valve with inherent irregularities. This reflects the significance of paravalvular leak as a complication and highlights a main difference with surgical procedures, where pathological tissue is excised to allow replacement with differently designed prostheses. Moderate-severe paravalvular leak was recognized early on as a critical factor in initial surgical versus TAVI comparisons, with the argument that new device generations would correct this. However, the impact of mild paravalvular leak has been controversial, with varying evidence across studies and follow-up durations. Added to the complexity of echocardiographic grading of some leaks, this led to the classification of mild or lesser leaks as a technical success, excluding moderate-severe degrees.

The following work comprehensively examines the impact of paravalvular leak after TAVI, consolidating the scientific evidence available. Authored by cardiologists, it serves as a reference for professionals involved in TAVI device implantation programs. With notable social media traction, it will likely influence future consensus documents. Its significance lies in its meta-analysis using patient-level data and extended follow-ups of up to 12 years. The study encompasses international experience with this procedure, highlighting registries such as Japan’s OCEAN-TAVI, SAPIEN-3, UK-TAVI, Brazilian, German GARY, French FRANCE 2, Italy’s CoreValve registry, and major clinical trials like PARTNER, PARTNER 2, US Pivotal CoreValve high-risk, NOTION, SURTAVI, CHOICE, PRAGMATIC, and REVIVAL. In total, 38 studies, encompassing 25,164 individual patients; 61% with no residual paravalvular leak. Among the 39% with paravalvular leak, approximately 25.6% presented moderate-severe leak, while 74.4% had mild leak. Patients with any degree of paravalvular leak faced a 50% higher risk of all-cause or cardiovascular mortality and an 81% increased readmission rate (p < 0.001). For moderate-severe leaks, these three outcomes were more than double compared to patients without residual leak (p < 0.001). Mild leaks were associated with 35% higher all-cause mortality, 27% higher cardiovascular mortality, and a 64% increase in readmission likelihood (p < 0.001).

The authors conclude that any degree of residual paravalvular leak after TAVI is linked to an increased risk of adverse events, including higher all-cause and cardiovascular mortality, as well as the need for rehospitalization. Although the impact of moderate-severe leaks is greater than mild leaks, the latter exhibits persistent adverse effects that seem to intensify over time.

COMMENTARY:

The work by Pompeu Sá et al. is the largest meta-analysis on the impact of paravalvular leak after TAVI. Prior blog entries have discussed potential etiopathogenetic mechanisms contributing to the poor outcomes in these patients, which can be summarized as follows:

– Impact of regurgitant volume on ventricular function, particularly in patients with established diastolic dysfunction, especially in cases initially graded as mild but actually more severe or progressing over time.

– Development or persistence of blood disorders, such as acquired von Willebrand factor deficiency and Heyde syndrome.

– Complications associated with paravalvular leak, including hemolysis and endocarditis, and the progression of the leak itself, which further exacerbates the initial conditions.

These findings underscore the need to maximize efforts to avoid any degree of paravalvular leak, even mild, from the treatment planning phase, extending into selection. This approach is especially crucial in patients with longer life expectancy, challenging the recommendation to lower implantation age for patients under 75 with suitable life expectancy. The added complexity of further interventions or reoperations is examined in other blog entries and will also serve as a counterargument against this approach.

The reduction in life expectancy to a half or third in patients with moderate-severe paravalvular leak is well-documented in the literature, and this study’s findings are consistent with this. However, excluding certain high-risk subgroups (e.g., bicuspid aortic valve and/or left ventricular outflow tract calcification, especially with self-expandable devices) is insufficient, as moderate-severe leaks occur in only 10% of procedures, leaving 30% with paravalvular leaks (three-quarters of the 40% presenting any leak grade), where patients also face adverse clinical trajectories. Moreover, high degrees of calcification, particularly asymmetrical, are predictors of complications like rhythm disorders, further compromising these patients’ survival and quality of life. While the authors recommend considering reintervention (balloon post-dilation or closure device) only in patients with TAVI and moderate-severe or mild leak with recurrent hospitalizations for heart failure, perhaps a more proactive approach would be beneficial. In patients with acceptable surgical risk, opting for aortic valve replacement with a bioprosthesis—offering <2% mortality, <1% paravalvular leak rate, and <5% pacemaker implantation requirement—might be the best solution.

In conclusion, while surgical invasiveness is undeniable, its gradual yet steady refinement over decades has yielded reliable outcomes, meeting the complex needs of modern patients. Pompeu Sá et al.’s article serves as a call for accountability, as optimal outcomes stem not only from well-executed procedures but also from sound indications. Although TAVI’s technological evolution is indisputable, let us proceed with caution as we push its boundaries, guided by common sense.

REFERENCE:

Pompeu Sá M, Jacquemyn X, Van den Eynde J, Tasoudis P, Erten O, Sicouri S, et al. Impact of paravalvular leak on outcomes after transcatheter aortic valve implantation: Meta-analysis of Kaplan-Meier-derived individual patient data. Structural Heart. 2023;7(2):10018. doi: 10.1016/j.shj.2022.100118.