Transcatheter Aortic Valve Replacement for Failed Surgical or Transcatheter Bioprosthetic Valves: A Comprehensive Review

Transcatheter aortic valve replacement (TAVR) has proven to be a safe, effective, and less invasive approach to aortic valve replacement in patients with aortic stenosis. In patients who underwent prior aortic valve replacement, transcatheter and surgical bioprosthetic valve dysfunction may occur as a result of structural deterioration or nonstructural causes such as prosthesis-patient mismatch (PPM) and paravalvular regurgitation. Valve-in-Valve (ViV) TAVR is a procedure that is being increasingly utilized for the replacement of failed transcatheter or surgical bioprosthetic aortic valves. Data regarding long-term outcomes are limited due to the recency of the procedure's approval, but available data regarding the short- and long-term outcomes of ViV TAVR are promising. Studies have shown a reduction in perioperative and 30-day mortality with ViV TAVR procedures compared to redo surgical repair of failed bioprosthetic aortic valves, but 1-year and 5-year mortality rates are more controversial and lack sufficient data. Despite the reduction in 30-day mortality, PPM and rates of coronary obstruction are higher in ViV TAVR as compared to both redo surgical valve repair and native TAVR procedures. New transcatheter heart valve designs and new procedural techniques have been developed to reduce the risk of PPM and coronary obstruction. Newer generation valves, new procedural techniques, and increased operator experience with ViV TAVR may improve patient outcomes; however, further studies are needed to better understand the safety, efficacy, and durability of ViV TAVR.

Do postoperative hemodynamic parameters add prognostic value for mortality after surgical aortic valve replacement?

Background

Although various hemodynamic parameters to assess prosthetic performance are available, prosthesis-patient mismatch (PPM) is defined exclusively by effective orifice area (EOA) index thresholds. Adjusting for the Society of Thoracic Surgeons predicted risk of mortality (STS PROM), we aimed to explore the added value of postoperative hemodynamic parameters for the prediction of all-cause mortality at 5 years after aortic valve replacement.

Methods

Data were obtained from the Pericardial Surgical Aortic Valve Replacement (PERIGON) Pivotal Trial, a multicenter prospective cohort study examining the performance of the Avalus bioprosthesis. Candidate predictors were assessed at the first follow-up visit; patients who had no echocardiography data, withdrew consent, or died before this visit were excluded. Candidate predictors included peak jet velocity, mean pressure gradient, EOA, predicted and measured EOA index, Doppler velocity index, indexed internal prosthesis orifice area, and categories for PPM. The performance of Cox models was investigated using the c-statistic and net reclassification improvement (NRI), among other tools.

Results

A total of 1118 patients received the study valve, of whom 1022 were eligible for the present analysis. In univariable analysis, STS PROM was the sole significant predictor of all-cause mortality (hazard ratio, 1.40; 95% confidence interval, 1.26-1.55). When extending the STS PROM with single hemodynamic parameters, neither the c-statistics nor the NRIs demonstrated added prognostic value compared to a model with STS PROM alone. Similar findings were observed when multiple hemodynamic parameters were added.

Conclusions

The STS PROM was found to be the main predictor of patient prognosis. The additional prognostic value of postoperative hemodynamic parameters for the prediction of all-cause mortality was limited.

Prosthesis-Patient Mismatch and Aortic Root Enlargement: Indications, Techniques and Outcomes

Prosthesis-patient mismatch (PPM) is defined as implanting a prosthetic that is insufficiently sized for the patient receiving it. PPM leads to high residual transvalvular gradients post-aortic valve replacement and consequently results in left ventricular dysfunction, morbidity and mortality in both the short and long term. Younger patients and patients with poor preoperative left ventricular function are more vulnerable to increased mortality secondary to PPM. There is debate over the measurement of valvular effective orifice area (EOA) and variation exists in how manufacturers report the EOA. The most reliable technique is using in vivo echocardiographic measurements to create tables of predicted EOAs for different valve sizes. PPM can be prevented surgically in patients at risk through aortic root enlargement (ARE). Established techniques include the posterior enlargement through Nicks and Manouguian procedures, and aortico-ventriculoplasty with the Konno-Rastan procedure, which allows for a greater enlargement but carries increased surgical risk. A contemporary development is the Yang procedure, which uses a Y-shaped incision created through the non- and left-coronary cusp commissure, undermining the nadirs of the non- and left-coronary cusps. Early results are promising and demonstrate an ability to safely increase the aortic root by up to two to three sizes. Aortic root enlargement thus remains a valuable and safe tool in addressing PPM, and should be considered during surgical planning.

Explant vs Redo-TAVR After Transcatheter Valve Failure: Mid-Term Outcomes From the EXPLANTORREDO-TAVR International Registry

BACKGROUND

Valve reintervention after transcatheter aortic valve replacement (TAVR) failure has not been studied in detail.

OBJECTIVES

The authors sought to determine outcomes of TAVR surgical explantation (TAVR-explant) vs redo-TAVR because they are largely unknown.

METHODS

From May 2009 to February 2022, 396 patients in the international EXPLANTORREDO-TAVR registry underwent TAVR-explant (181, 46.4%) or redo-TAVR (215, 54.3%) for transcatheter heart valve (THV) failure during a separate admission from the initial TAVR. Outcomes were reported at 30 days and 1 year.

RESULTS

The incidence of reintervention after THV failure was 0.59% with increasing volume during the study period. Median time from index-TAVR to reintervention was shorter in TAVR-explant vs redo-TAVR (17.6 months [IQR: 5.0-40.7 months] vs 45.7 months [IQR: 10.6-75.6 months]; P < 0.001], respectively. TAVR-explant had more prosthesis-patient mismatch (17.1% vs 0.5%; P < 0.001) as the indication for reintervention, whereas redo-TAVR had more structural valve degeneration (63.7% vs 51.9%; P = 0.023), with a similar incidence of ≥moderate paravalvular leak between groups (28.7% vs 32.8% in redo-TAVR; P = 0.44). There was a similar proportion of balloon-expandable THV failures (39.8% TAVR-explant vs 40.5% redo-TAVR; P = 0.92). Median follow-up was 11.3 (IQR: 1.6-27.1 months) after reintervention. Compared with redo-TAVR, TAVR-explant had higher mortality at 30 days (13.6% vs 3.4%; P < 0.001) and 1 year (32.4% vs 15.4%; P = 0.001), with similar stroke rates between groups. On landmark analysis, mortality was similar between groups after 30 days (P = 0.91).

CONCLUSIONS

In this first report of the EXPLANTORREDO-TAVR global registry, TAVR-explant had a shorter median time to reintervention, with less structural valve degeneration, more prosthesis-patient mismatch, and similar paravalvular leak rates compared with redo-TAVR. TAVR-explant had higher mortality at 30 days and 1 year, but similar rates on landmark analysis after 30 days.

Reclassification of prosthesis-patient mismatch after transcatheter aortic valve replacement using predicted vs. measured indexed effective orifice area

AIMS

The objective was to compare the incidence and impact on outcomes of measured (PPMM) vs. predicted (PPMP) prosthesis-patient mismatch following transcatheter aortic valve replacement (TAVR).

METHODS AND RESULTS

All consecutives patients who underwent TAVR between 2007 and 2018 were included. Effective orifice area (EOA) was measured by Doppler-echocardiography using the continuity equation and predicted according to the normal reference for each model and size of valve. PPM was defined using EOA indexed (EOAi) to body surface area as moderate if ≤0.85 cm2/m2 and severe if ≤ 0.65 cm2/m2 (respectively, ≤ 0.70 and ≤ 0.55 cm2/m2 if body mass index ≥ 30 kg/m2). The outcome endpoints were high residual gradient (≥20 mmHg) and the composite of cardiovascular mortality and hospital readmission for heart failure at 1 year. Overall, 1088 patients underwent a TAVR (55% male, age 79.1 ± 8.4 years, and STS score 6.6 ± 4.7%); balloon-expandable device was used in 83%. Incidence of moderate (10% vs. 27%) and severe (1% vs. 17%) PPM was markedly lower when defined by predicted vs. measured EOAi (P < 0.001). Balloon-expandable device implantation (OR: 1.90, P = 0.029) and valve-in-valve procedure (n = 118; OR: 3.21, P < 0.001) were the main factors associated with PPM occurrence. Compared with measured PPM, predicted PPM showed stronger association with high residual gradient. Severe measured or predicted PPM was not associated with clinical outcomes.

CONCLUSION

The utilization of the predicted EOAi reclassifies the majority of patients with PPM to no PPM following TAVR. Compared with measured PPM, predicted PPM had stronger association with haemodynamic outcomes, while both methods were not associated with clinical outcomes.

The fallacy of indexed effective orifice area charts to predict prosthesis-patient mismatch after prosthesis implantation

Aims 

Indexed effective orifice area (EOAi) charts are used to determine the likelihood of prosthesis–patient mismatch (PPM) after aortic valve replacement (AVR). The aim of this study is to validate whether these EOAi charts, based on echocardiographic normal reference values, can accurately predict PPM.

Methods and results 

In the PERIcardial SurGical AOrtic Valve ReplacemeNt (PERIGON) Pivotal Trial, 986 patients with aortic valve stenosis/regurgitation underwent AVR with an Avalus valve. Patients were randomly split (50:50) into training and test sets. The mean measured EOAs for each valve size from the training set were used to create an Avalus EOAi chart. This chart was subsequently used to predict PPM in the test set and measures of diagnostic accuracy (sensitivity, specificity, and negative and positive predictive value) were assessed. PPM was defined by an EOAi ≤0.85 cm²/m^2, and severe PPM was defined as EOAi ≤0.65 cm²/m². The reference values obtained from the training set ranged from 1.27 cm² for size 19 mm up to 1.81 cm² for size 27 mm. The test set had an incidence of 66% of PPM and 24% of severe PPM. The EOAi chart inaccurately predicted PPM in 30% of patients and severe PPM in 22% of patients. For the prediction of PPM, the sensitivity was 87% and the specificity 37%. For the prediction of severe PPM, the sensitivity was 13% and the specificity 98%.

Conclusion 

The use of echocardiographic normal reference values for EOAi charts to predict PPM is unreliable due to the large proportion of misclassifications.

Why the categorization of indexed effective orifice area is not justified for the classification of prosthesis-patient mismatch

OBJECTIVES

Although the impact of prosthesis-patient mismatch (PPM) on survival has been widely studied, there has been little debate about whether the current definition of PPM truly reflects hemodynamic obstruction. This study aimed to validate the categorization of indexed effective orifice area (EOAi) for the classification of PPM.

METHODS

In total, 2171 patients who underwent aortic valve replacement with a surgical stented bioprosthesis in 5 trials (CoreValve US High-Risk, SURTAVI [Surgical Replacement and Transcatheter Aortic Valve Implantation Trial], Evolut Low Risk, PERIGON [PERIcardial SurGical AOrtic Valve ReplacemeNt] Pivotal Trial for the Avalus valve, and PERIGON Japan) were used for this analysis. The echocardiographic images at the 1-year follow-up visit were evaluated to explore the association between EOAi and mean aortic gradient and its interaction with other patient characteristics, including obesity. In addition, different criteria of PPM were compared with reflect elevated mean aortic gradients (≥20 mm Hg).

RESULTS

A relatively smaller exponential decay in mean aortic gradient was found for increasing EOAi, as the slope on the log scale was -0.83 versus -2.5 in the publication from which the current cut-offs for PPM originate. The accuracy of the American Society of Echocardiography, Valve Academic Research Consortium-2, and European Association of Cardiovascular Imaging definitions of PPM to reflect elevated mean aortic gradients was 49%, 57%, and 57%, respectively. The relation between EOAi and mean aortic gradient was not significantly different between obese and non-obese patients (P = .20).

CONCLUSIONS

The use of EOAi thresholds to classify patients with PPM is undermined by a less-pronounced exponential relationship between EOAi and mean aortic gradient than previously demonstrated. Moreover, recent adjustment for obesity in the definition of PPM is not supported by these data.

Early evaluation of the aortic root after Nicks' procedure

Objective(s)

To determine the influence of surgical techniques adopted to avoid suture line disruption, periprosthetic leakage, patch dislodgement, pericardial patch aneurysm formation, and the long-term stability of aortic root enlargement (ARE) during aortic valve replacement (AVR).

Methods

One hundred fifteen patients undergoing AVR or combined aortic and mitral valve replacements with Nicks' posterior ARE between 1997 and 2019 underwent long-term echocardiographic and angio-computed tomographic evaluation. Age was 11-72 years (AVR: median, 30; interquartile range, 21-47 years; AVR and mitral valve replacement: median, 27.5; interquartile range, 20-37.5 years). The aortotomy was closed using autologous pericardial patch and Teflon-buttressed sutures.

Results

Hospital mortality was 1.7% (n = 2), with 4 (3.5%) late deaths. At a mean follow-up of 123.11 ± 77.67 months, the survival probability from Kaplan–Meier was 93.25 ± 0.03%. No cases of severe prosthesis–patient mismatch (PPM) were observed, and only 2 patients had moderate PPM. Median aortic root diameters at the level of sinus of Valsalva and sinotubular junction were 32 (29-35) mm and 33 (30-36) mm, respectively, at discharge, and were 33 (30-36) mm, and 33 (31-37) mm, respectively, at latest follow-up, with no cases of late pericardial patch aneurysm.

Conclusions

ARE is a safe adjunct to AVR in patients with a small aortic annulus to prevent PPM. Retention of a pericardial collar and Teflon-buttressed sutures is an expedient, safe, and effective technique in reducing bleeding at the enlarged ventriculo-aortic junction. Autologous pericardial patch aortoplasty is not associated with late aneurysm/pseudoaneurysm formation.

Impact of Valve Size on Prosthesis-Patient Mismatch and Aortic Valve Gradient After Transcatheter versus Surgical Aortic Valve Replacement

OBJECTIVE

Limited data is available about the effect of implanted valve size on prosthesis-patient mismatch (PPM) incidence and aortic gradient (AG) after transcatheter aortic valve replacement (TAVR) and surgical aortic valve replacement (SAVR). We compared PPM incidence and postprocedural AG between TAVR and SAVR patients considering the impact of implanted valve size.

METHODS

From March 20, 2012, to September 30, 2015, 563 consecutive patients underwent TAVR (n = 419) or isolated SAVR (n = 144). Postprocedural transthoracic echocardiography was obtained within 30 days; AG, effective orifice area (EOA), and EOA index were calculated.

RESULTS

A total of 381 patients in TAVR group and 82 patients in SAVR group were included. Mean preoperative AG and mean aortic valve area were not significantly different between the 2 groups. Postprocedural AG was significantly lower in TAVR than SAVR group, 7.74 ± 5.39 versus 14.27 ± 8.16 (P < 0.001). Between patients who had TAVR and SAVR with a valve size ≤23 mm, SAVR patients were 3 times more likely to have greater than mild AG after the procedure, OR: 3.1 (95% CI, 1.1 to 8.9) (P < 0.001). PPM incidence was significantly higher in SAVR group than TAVR group, 44 (53.7%) versus 112 (29.4%), OR = 2.8 (95% CI, 1.7 to 4.5) (P < 0.001). The PPM incidence was also higher in SAVR group than TAVR group among those who had the procedures with a valve size ≤23 mm, 35 (64.8%) versus 56 (47.9%), OR = 2 (95% CI, 1.1 to 3.9) (P = 0.048). Postprocedural outcomes were comparable between the 2 groups.

CONCLUSIONS

In comparison to SAVR, TAVR is associated with less PPM and lower AG, especially in patients receiving a valve size ≤23 mm.

Geometric changes in ventriculoaortic complex after transcatheter aortic valve replacement and its association with post-procedural prosthesis-patient mismatch: an intraprocedural 3D-TEE study

AIMS

Prosthesis-patient mismatch (PPM) after transcatheter aortic valve replacement (TAVR) leads to increased mortality. However, its peri-procedural determinants remain unknown. We investigated geometric changes in aortic annulus (AoA) and left ventricular outflow tract (LVOT) during TAVR by three-dimensional transoesophageal echocardiography (3D-TEE) and its association with post-procedural PPM.

METHODS AND RESULTS

A total of 131 patients with severe aortic stenosis underwent intraprocedural 3D-TEE during balloon-expandable TAVR. The severity of PPM was graded using the indexed effective orifice area calculated by Doppler echocardiography at discharge, with moderate defined as ≥0.65 and ≤0.85 cm²/m² and severe defined as <0.65 cm²/m². 3D planimetered AoA area decreased after TAVR (P< 0.001), whereas the LVOT increased (P= 0.004). The eccentricity of both AoA and LVOT decreased after TAVR (both, P< 0.001). At discharge, the incidence of overall and severe PPM was 44 and 12%, respectively. Patients with PPM had a larger body surface area, smaller aortic valve area, and less frequent balloon dilation (all P< 0.05). Patients with PPM had a lower post-TAVR AoA area/pre-TAVR AoA area (91 ± 8 vs. 95 ± 7%, P= 0.001) than those without PPM. The post-TAVR AoA area/pre-TAVR AoA area was independently associated with overall PPM (odds ratio, 1.80; 95% CI, 1.06-3.05; P= 0.031) and severe PPM (odds ratio, 2.50; 95% CI, 1.05-5.36; P= 0.04). Additionally, a cut-off value of this ratio >86.3% had a sensitivity of 84% and a specificity of 44% for the prevention of severe PPM.

CONCLUSION

3D-TEE can evaluate geometric changes in AoA and LVOT during balloon-expandable TAVR and predicts post-procedural PPM.