Evaluación multimodal de la degeneración estructural de válvulas percutáneas en el seguimiento a largo plazo

Durability of transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) is now utilised as a less invasive alternative to surgical aortic valve replacement (SAVR) across the whole spectrum of surgical risk. Long-term durability of the bioprosthetic valves has become a key goal of TAVI as this procedure is now considered for younger and lower-risk populations. The purpose of this article is to present a state-of-the-art overview on the definition, aetiology, risk factors, mechanisms, diagnosis, clinical impact, and management of bioprosthetic valve dysfunction (BVD) and failure (BVF) following TAVI with a comparative perspective versus SAVR. Structural valve deterioration (SVD) is the main factor limiting the durability of the bioprosthetic valves used for TAVI or SAVR, but non-structural BVD, such as prosthesis-patient mismatch and paravalvular regurgitation, as well as valve thrombosis or endocarditis may also lead to BVF. The incidence of BVF related to SVD or other causes is low (<5%) at midterm (5- to 8-year) follow-up and compares favourably with that of SAVR. The long-term follow-up data of randomised trials conducted with the first generations of transcatheter heart valves also suggest similar valve durability in TAVI versus SAVR at 10 years, but these trials suffer from major survivorship bias, and the long-term durability of TAVI will need to be confirmed by the analysis of the low-risk TAVI versus SAVR trials at 10 years.

Preoperative hypomagnesemia as a possible predictive factor for postoperative increase of transvalvular pressure gradient in hemodialysis patients treated with transcatheter aortic valve implantation

BACKGROUND

Patients undergoing maintenance hemodialysis (HD) with severe aortic stenosis are at a high risk for bioprosthetic valve dysfunction after transcatheter aortic valve implantation (TAVI). Currently, preoperative factors that predict the occurrence of valve dysfunction after TAVI on HD patients remain to be elucidated. The aim of this study is to analyze the association between preoperative clinical factors and valve stenosis after TAVI on HD patients.

METHODS

Twenty-four of HD patients who underwent TAVI at our institution between April 2012 and January 2016 were analyzed. The mean aortic transvalvular pressure gradient (MPG) and effective orifice area index (EOAi) were assessed by serial echocardiography. Associations between preoperative clinical factors and time-series changes in MPG were examined using mixed-effects linear regression model for repeated measures.

RESULTS

Three patients developed severe structural valve deterioration with calcific valve stenosis requiring reoperation. A multivariate linear mixed-effects model showed that lower serum magnesium (sMg) levels were associated with the increase of MPG after TAVI (beta-coefficient = 0.019, p = 0.03). No correlation was observed with serum calcium, phosphorus, or intact parathyroid hormone. Time-series changes of MPG and EOAi had significant difference between lower and higher sMg group. All 3 of the patients who underwent reoperation showed lower preoperative sMgs.

CONCLUSION

Among bone-mineral metabolism markers, preoperative hypomagnesemia was associated with the increase of MPG after TAVI, suggesting that hypomagnesemia could predict post-TAVI valve dysfunction in HD patients. Further studies with larger sample sizes are warranted.

Macroscopic and microscopic features of surgically explanted transcatheter aortic valve prostheses

OBJECTIVES

With the extended indications of transcatheter aortic valve (TAV) replacement (TAVR) to lower-risk patients, there is an increasing number of patients requiring surgical explantation of failed TAV. We sought to describe macroscopic and microscopic features of surgically explanted percutaneous aortic valve prostheses.

METHODS

Preoperative and surgical characteristic of patients undergoing surgical explantation of TAV were retrospectively analyzed from 2007 to 2020. Surgical and pathologic features of these valves, and outcomes of the surgical valve replacement were described.

RESULTS

Out of 1764 patients who underwent a TAVR procedure, 21 were operated for TAV failure. Isolated or combined indications for surgery included: significant paravalvular leak (n = 15), delayed prosthesis migration (n = 5), significant increase of trans-TAV gradients (n = 6), and endocarditis (n = 3). Mean time elapsed between TAVR and explantations was 674.9 ± 803.9 days. Macroscopic lesions found on explanted percutaneous valves were severe adhesions to the aorta (n = 10), calcifications (n = 7), leaflet thrombosis (n = 4), and vegetations (n = 3). Except for patients with endocarditis, one or more pathological lesions were found in 15 patients. Pathology analyses on these valves showed fibro-calcific degenerations (n = 12), pannus formation (n = 9), and chronic inflammation (n = 3). One patient (4.8%) died after surgical explantation, and 13 (61.9%) had concomitant procedures. The survival rate at 1 year was 94.4%.

CONCLUSIONS

Microscopic findings of fibro-calcific leaflet degeneration, and pannus formation in addition to macroscopic calcification and thrombosis present early, (within a mean of 2 years) after TAVR. Further investigation with a higher number of patients and echocardiographic follow-up is warranted.