Benchmarking Outcomes: Reoperation for Aortic Valve Patient-Prosthesis Mismatch

A Retrospective Analysis of Standardized Gradient Calculations for Evaluating Patient-Prosthesis Mismatch Following Mechanical Aortic Valve Replacement

Background: Aortic stenosis (AS) is one of the most common valvular heart diseases, particularly in the elderly, with a prevalence of approximately 3% in individuals over 75 years of age. Aortic valve replacement (AVR) remains the standard treatment, yet postoperative hemodynamic assessment is often complicated by variations in prosthetic valve size, left ventricular ejection fraction (LVEF), effective orifice area (EOA), and body surface area (BSA). These factors significantly influence prosthetic valve function and contribute to patient-prosthesis mismatch (PPM), which has been associated with worse clinical outcomes. Traditional transvalvular gradient measurements often fail to account for these patient-specific variables. This study introduces a novel approach to standardized gradient calculations, aiming to enhance the accuracy and comparability of prosthetic valve assessments. Methods: A retrospective analysis was conducted on 115 patients who underwent mechanical AVR at a single center. Patients were categorized into three groups based on the prosthetic valve type: St. Jude Medical (SJM) HP (n = 31); SJM Regent (n = 54); and those who underwent aortic root enlargement (ARE) (n = 30). Preoperative and postoperative transthoracic echocardiography (TTE) was performed to measure conventional and standardized transvalvular gradients. Four novel standardized gradient calculations were developed to adjust for individual hemodynamic differences, improving the accuracy of prosthetic valve function assessment. Results: Standardized gradient calculations demonstrated significant differences between prosthesis types. Postoperative standardized gradients were significantly higher in the SJM HP group compared to the SJM Regent and aortic-root-enlargement groups (p < 0.001, p < 0.05). The lowest standardized gradients were observed in patients who received the SJM Regent prostheses (p < 0.05). Although conventional measurements showed no significant differences, standardized calculations revealed that patients with 19 mm prostheses exhibited significantly higher transvalvular gradients than those with 21 mm prostheses (p < 0.05), emphasizing the clinical importance of prosthesis size in postoperative hemodynamics. Conclusions: Standardized gradient calculations provide a more objective, reliable, and patient-specific assessment of prosthetic valve function by minimizing interpatient variability. This approach improves the detection of patient-prosthesis mismatch and optimizes postoperative hemodynamic evaluation, potentially leading to better prosthesis selection and surgical decision-making. However, further validation is required in larger cohorts before these methods can be widely adopted into clinical practice. Future studies should assess their impact on long-term clinical outcomes, including left ventricular remodeling and patient survival.

True redo-aortic root replacement versus root replacement after any previous surgery

Objective

The impact of previous aortic root replacement (True-Redo) versus any previous operation (Any-Redo) on outcomes after reoperative aortic root replacement (redo-ROOT) is largely unknown. In this first multi-institutional study, the clinical impact True-Redo versus Any-Redo in the setting of redo-ROOT was reviewed.

Methods

From 2004 to 2021, 822 patients underwent redo-ROOT at 2 major academic centers: 638 Any-Redo and 184 True-Redo. Matching based on preoperative demographics and concomitant operations resulted in 174 matched pairs. An independent risk factor analysis was performed to determine risk factors for early and late mortality.

Results

Patients in the True-Redo group were younger, at 49.9 ± 15.1 versus 55.3 ± 14.7 years, P < .001. Concomitant operations were largely similar between the 2 groups, P > .05. Median cardiopulmonary bypass time (P < .001) and aortic crossclamp time (P = .03) were longer for True-Redo group. In-hospital mortality was 13% (109) and was without significant difference between groups, P = .41. Ten-year survival was 78% versus 76% for True-Redo versus Any-Redo groups respectively, P = .7. Landmark survival analysis at 4 years' postoperatively on the matched groups found that patients in the True-Redo group had improved survival outcomes (P = .046). Risk factors of in-hospital mortality consisted of older age (P < .0001), lower ejection fraction (P = .02), and male patient (P = .0003).

Conclusions

Clinical outcomes following redo-ROOT are excellent. Performance of a True-Redo-ROOT does not result in worse in-hospital morbidity or mortality and has improved survival benefit at midterm follow-up when compared with patients in the Any-Redo group. The decision to perform a redo-ROOT must be taken seriously and must be individualized in a patient-specific manner for optimal outcomes.

Transcatheter Aortic Valve Implantation for Bioprosthetic Valve Failure: Placement of Aortic Transcatheter Valves 3 Aortic Valve-in-Valve Study

Background

Transcatheter aortic valve implantation is safe and effective for high-risk patients with bioprosthetic valve failure (BVF) but has not been studied in low- and intermediate-risk patients. One year outcomes of the PARTNER 3 Aortic Valve-in-valve (AViV) Study were evaluated.

Methods

This prospective, single-arm, multicenter study enrolled 100 patients from 29 sites with surgical BVF. The primary endpoint was a composite of all-cause mortality and stroke at 1 year. The key secondary outcomes included mean gradient, functional capacity, and rehospitalization (valve-related, procedure-related, or heart failure related).

Results

A total of 97 patients underwent AViV with a balloon-expandable valve from 2017 to 2019. Patients were 79.4% male with a mean age of 67.1 years and Society of Thoracic Surgeons score of 2.9%. The primary endpoint occurred in 2 patients (2.1%) who had strokes; there was no mortality at 1 year. Five patients (5.2%) had valve thrombosis events, and 9 patients (9.3%) had rehospitalizations, including 2 (2.1%) for strokes, 1 (1.0%) for heart failure, and 6 (6.2%) for aortic valve reinterventions (3 explants, 3 balloon dilations, and 1 percutaneous paravalvular regurgitation closure). From baseline to 1 year, New York Heart Association class III/IV decreased from 43.3% to 4.5%, mean gradient from 39.1 ± 18.2 mm Hg to 19.7 ± 7.6 mm Hg, and ≥moderate aortic regurgitation from 41.1% to 1.1%.

Conclusions

AViV with a balloon-expandable valve improved hemodynamic and functional status at 1 year and can provide an additional therapeutic option in selected low- or intermediate-risk patients with surgical BVF, although longer term follow-up is necessary.

Patient Prosthesis Mismatch After SAVR and TAVR

Patient-prosthesis mismatch (PPM) remains one out of many factors to be considered during decision-making for the treatment of aortic valve pathologies. The idea of adequate sizing of a prosthetic heart valve was established by Rahimtoola already in 1978. In this article, the author described the phenomenon that the orifice area of a prosthetic heart valve may be too small for the individual patient. PPM is assessed by measurement or projection of the prosthetic effective orifice area indexed to body surface area (iEOA), while it is recommended to use different cut point values for non-obese and obese patients for the categorization of moderate and severe PPM. Several factors influence the accuracy of both the projected and the measured iEOA for PPM assessment, which leads to a certain number of false assignments to the PPM or no PPM group. Despite divergent findings on the impact of PPM on clinical outcomes, there is consensus that PPM should be avoided to prevent sequelae of increased prosthetic gradients after aortic valve replacement. To prevent PPM, it is required to anticipate the iEOA of the prosthesis prior to the procedure. The use of adequate reference tables, derived from echocardiographically measured mean effective orifice area (EOA) values from preferably large numbers of patients, is most appropriate to predict the iEOA. Such tables should be used also for transcatheter heart valves in the future. During the decision-making process, all available options should be taken into account for the individual patient. If the predicted size and type of a surgical prosthesis cannot be implanted, additional surgical procedures, such as annular enlargement with the Manougian technique, or alternative procedures, such as transcatheter aortic valve implantation (TAVI) can prevent PPM. PPM prevention for TAVI patients is a new field of interest and includes anticipation of the iEOA, prosthesis selection, and procedural strategies.