Can Balloon Aortic Valvuloplasty Help Determine Appropriate Transcatheter Aortic Valve Size?

A retrospective study on the trends in surgical aortic valve replacement outcomes in the post-transcatheter aortic valve replacement era

Background and Aims

Transcatheter aortic valve replacement (TAVR) is the mainstay of treatment of inoperable and severe high-risk aortic stenosis and is noninferior to surgical aortic valve replacement (SAVR) for low-risk and intermediate-risk patients as well. We aim to compare the valve size, area, and transaortic mean gradients in SAVR patients before and after the implementation of TAVR since being approved by the Food and Drug Administration  in 2011.

Methods

Patients who underwent a bioprosthetic SAVR placement were divided into two groups based on the date of procedure: the early pre-TAVR implementation group (years 2011-2012) and the contemporary post-TAVR group (years 2019-2020). The primary endpoint was the mean gradient across the aortic valve within 16 months of surgery. The secondary endpoints included the difference in valve size and various aortic valve echocardiographic variables.

Results

One hundred and thirty patients had their valves replaced in the years 2011-2012 and 134 in the years 2019-2020. The early group had a significantly higher mean gradient (median of 13 mmHg [interquartile range, IQR: 9.3-18] vs. 10 mmHg [IQR: 7.5-13.1], p = 0.001) and a smaller median effective orifice area index (0.8 cm2/m2 [IQR: 0.6-1] vs. 1.1 cm2/m2 [IQR: 0.8-1.3], p < 0.001). The median valve size was significantly smaller in the early group (median of 21 mm [IQR: 21-23] vs. 23 mm [IQR: 22.5-25], p < 0.001).

Conclusion

In the contemporary era, surgical patients receive larger valves which translates into lower mean gradients, larger valve area, and lower rates of patient-prosthesis mismatch than in previous years before the routine introduction of TAVR.

Undersizing but overfilling eliminates the gray zones of sizing for transcatheter aortic valve replacement with the balloon-expandable bioprosthesis

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Transcatheter heart valve size selection is still challenging.

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The overlap between two different prosthesis sizes for borderline annuli remains.

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Undersizing but overfilling improves sizing in borderline annulus cases.

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Undersizing but overfilling decreases the postprocedural THV-pressure gradient.

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Prospective studies are needed considering the TAVR expansion to younger patients.

Background

Current recommendations for valve size selection are based on multidimensional annular measurements, yet the overlap between two different transcatheter heart valve (THV) sizes remains. We sought to evaluate whether undersizing but overfilling eliminates the gray zones of valve sizing.

Methods

Data of 246 consecutive patients undergoing transcatheter aortic valve replacement (TAVR) with the balloon-expandable bioprosthesis with either conventional sizing and nominal filling (group 1 (NF-TAVR), n = 154) or undersizing but overfilling under a Less Is More (LIM)-Principle (group 2 (LIM-TAVR), n = 92) were compared. Paravalvular leakage (PVL) was graded angiographically and quantitatively using invasive hemodynamics.

Results

Annulus rupture (AR) occurred only in group 1 (n = 3). Due to AR adequate evaluation of PVL was possible in 152 patients of group 1. More than mild PVL was found in 13 (8.6%) patients of group 1 and 1 (1.1%) patient of group 2 (p = 0.019). Postdilatation was performed in 31 (20.1%) patients of group 1 and 6 patients (6.5%) of group 2 (p = 0.003). For patients with borderline annulus size in group 1 (n = 35, 22.7%) valve size selection was left to the physiciańs choice resulting in selection of the larger prosthesis in 10 (28.6%). In group 2 all patients with borderline annulus (n = 36, 39.1%) received the smaller prosthesis (LIM-TAVR). The postprocedural mean transvalvular pressure gradient was significantly higher in the NF-TAVR-group (11.7 ± 4 vs. 10.1 ± 3.6 mmHg, p = 0.005).

Conclusion

LIM-TAVR eliminates the gray zones of sizing and associated PVL, can improve THV-performance, reduce incidence of annular rupture and simplify the procedure especially in borderline cases.

Multimodality Imaging for Planning and Follow-up of Transcatheter Aortic Valve Replacement

The complementary modalities of Doppler echocardiography and multidetector computed tomography are most frequently used for the planning and follow-up of transcatheter aortic valve replacement (TAVR). TAVR is now a well-established modality in the treatment of high-risk and inoperable patients with symptomatic severe aortic stenosis. Furthermore, recent studies have shown that TAVR is equivalent or superior to surgical aortic valve replacement in patients at intermediate surgical risk. We review the most commonly used imaging modalities and discuss their respective strengths and contributions to optimal patient selection, procedure planning, implementation, and follow-up in TAVR.

Echocardiographic imaging of procedural complications during balloon-expandable transcatheter aortic valve replacement

Transcatheter aortic valve replacement (TAVR) using a balloon-expandable valve is an accepted alternative to surgical replacement for severe, symptomatic aortic stenosis in high risk or inoperable patients. Intraprocedural transesophageal echocardiography (TEE) offers real-time imaging guidance throughout the procedure and allows for rapid and accurate assessment of complications and procedural results. The value of intraprocedural TEE for TAVR will likely increase in the future as this procedure is performed in lower surgical risk patients, who also have lower risk for general anesthesia, but a greater expectation of optimal results with lower morbidity and mortality. This imaging compendium from the PARTNER (Placement of Aortic Transcatheter Valves) trials is intended to be a comprehensive compilation of intraprocedural complications imaged by intraprocedural TEE and diagnostic tools to anticipate and/or prevent their occurrence.

Comparison of aortic annulus size by transesophageal echocardiography and computed tomography angiography with direct surgical measurement

This study sought to compare the accuracy of 2-dimensional transesophageal echocardiography (TEE) and computed tomography angiography (CTA) for noninvasive aortic annular sizing as required for transcatheter aortic valve implantation (TAVI). Direct intraoperative (OR) sizing is the gold standard for aortic annular measurement in surgical aortic valve replacement. Unlike surgical aortic valve replacement, TAVI requires noninvasive assessment of aortic annular dimensions for determining the size of prosthesis to be implanted and controversy exists regarding the best imaging technique for TAVI sizing. Preoperative CTA and OR TEE images of the aortic annulus in 227 patients who underwent proximal aortic surgery with OR annular sizing at the Duke University Medical Center were reviewed. Both imaging techniques were compared with direct OR measurements of aortic annulus diameter using metric sizers as the gold standard. CTA overestimated aortic annulus diameter in 72.2% of cases, with 46.3% >1 TAVI valve-size (>3 mm) overestimations, whereas TEE underestimated aortic annulus diameter in 51.1% of cases, with 16.7% >1 valve-size underestimations. Combining both techniques improved the estimation of aortic annular size. In conclusion, there are limitations to current imaging techniques for noninvasive determination of aortic annular dimensions compared with direct OR sizing. Undersizing by TEE and oversizing by CTA are common and may be related to differences in methods for sizing an elliptical structure. Combining measurements from both techniques would decrease the false exclusion rate for TAVI eligibility because of size mismatch.

Two-in-one aortic valve sizing and valvuloplasty conductance balloon catheter

BACKGROUND

Inaccurate aortic valve sizing and selection is linked to paravalvular leakage in transcatheter aortic valve replacement (TAVR). Here, a novel sizing valvuloplasty conductance balloon (SVCB) catheter is shown to be accurate, reproducible, unbiased, and provides real-time tool for aortic valve sizing that fits within the standard valvuloplasty procedure.

METHODS AND RESULTS

The SVCB catheter is a valvuloplasty device that uses real-time electrical conductance measurements based on Ohm's Law to size the balloon opposed against the aortic valve at any given inflation pressure. Accuracy and repeatability of the SVCB catheter was performed on the bench in phantoms of known dimension and ex vivo in three domestic swine aortic annuli with comparison to computed tomography (CT) and dilator measurements. Procedural workflow and safety was demonstrated in vivo in three additional domestic swine. SVCB catheter measurements had negligible bias or error for bench accuracy considered as the gold standard (Bias: -0.11 ± 0.26 mm; Error: 1.2%), but greater disagreement in ex vivo versus dilators (Bias: -0.3 ± 1.1 mm; Error: 4.5%), and ex vivo versus CT (Bias: -1.0 ± 1.6 mm; Error: 8.7%). The dilator versus CT accuracy showed similar agreement (Bias: -0.9 ± 1.5 mm; Error: 7.3%). Repeatability was excellent on the bench (Bias: 0.02 ± 0.12 mm; Error: 0.5%) and ex vivo (Bias: -0.4 ± 0.9 mm; Error: 4.6%). In animal studies, the device fit well within the procedural workflow with no adverse events or complications.

CONCLUSIONS

Due to the clinical relevance of this accurate, repeatable, unbiased, and real-time sizing measurement, the SVCB catheter may provide a useful tool prior to TAVR. These findings merit a future human study.

CT-angiography-based evaluation of the aortic annulus for prosthesis sizing in transcatheter aortic valve implantation (TAVI)-predictive value and optimal thresholds for major anatomic parameters

BACKGROUND/OBJECTIVES

To evaluate the predictive value of CT-derived measurements of the aortic annulus for prosthesis sizing in transcatheter aortic valve implantation (TAVI) and to calculate optimal cutoff values for the selection of various prosthesis sizes.

METHODS

The local IRB waived approval for this single-center retrospective analysis. Of 441 consecutive TAVI-patients, 90 were excluded (death within 30 days: 13; more than mild aortic regurgitation: 10; other reasons: 67). In the remaining 351 patients, the CoreValve (Medtronic) and the Edwards Sapien XT valve (Edwards Lifesciences) were implanted in 235 and 116 patients. Optimal prosthesis size was determined during TAVI by inflation of a balloon catheter at the aortic annulus. All patients had undergone CT-angiography of the heart or body trunk prior to TAVI. Using these datasets, the diameter of the long and short axis as well as the circumference and the area of the aortic annulus were measured. Multi-Class Receiver-Operator-Curve analyses were used to determine the predictive value of all variables and to define optimal cutoff-values.

RESULTS

Differences between patients who underwent implantation of the small, medium or large prosthesis were significant for all except the large vs. medium CoreValve (all p's<0.05). Furthermore, mean diameter, annulus area and circumference had equally high predictive value for prosthesis size for both manufacturers (multi-class AUC's: 0.80, 0.88, 0.91, 0.88, 0.88, 0.89). Using the calculated optimal cutoff-values, prosthesis size is predicted correctly in 85% of cases.

CONCLUSION

CT-based aortic root measurements permit excellent prediction of the prosthesis size considered optimal during TAVI.

Preparatory balloon aortic valvuloplasty during transcatheter aortic valve implantation for improved valve sizing

OBJECTIVES

This study sought to evaluate whether supra-aortic angiography during preparatory balloon aortic valvuloplasty (BAV) improves valve sizing.

BACKGROUND

Current recommendations for valve size selection are based on annular measurements by transesophageal echocardiography and computed tomography, but paravalvular aortic regurgitation (PAR) is a frequent problem.

METHODS

Data of 270 consecutive patients with either conventional sizing (group 1, n = 167) or balloon aortic valvuloplasty-based sizing (group 2, n = 103) were compared. PAR was graded angiographically and quantitatively using several hemodynamic indices.

RESULTS

PAR was observed in 113 patients of group 1 and 41 patients of group 2 (67.7% vs. 39.8%, p < 0.001). More than mild PAR was found in 24 (14.4%) patients of group 1 and 8 (7.8%) patients of group 2. According to pre-interventional imaging, 40 (39%) patients had a borderline annulus size, raising uncertainty regarding valve size selection. Balloon sizing resulted in selection of the bigger prosthesis in 30 (29%) and the smaller prosthesis in the remaining patients, and only 1 of these 40 patients had more than mild PAR. As predicted by the hemodynamic indices of PAR, mortality at 30 days and 1 year was less in group 2 than in group 1 (5.8% vs. 9%, p = 0.2 and 10.6% vs. 20%, p = 0.01).

CONCLUSIONS

Preparatory balloon aortic valvuloplasty during transcatheter aortic valve implantation improves valve size selection, reduces the associated PAR, and increases survival in borderline cases.

Patient evaluation and selection for transcatheter aortic valve replacement: the heart team approach

Transcatheter aortic valve replacement (TAVR) has been shown to significantly impact mortality and quality of life in patients with severe aortic stenosis (AS) who are deemed high risk for surgical aortic valve replacement (SAVR). Essential to these outcomes is proper patient selection. The multidisciplinary TAVR heart team was created to provide comprehensive patient evaluation and aid in proper selection. This review with outline the history and components of the heart team, and delineate the team's role in risk and frailty assessment, evaluation of common co-morbidities that impact outcomes, and the complex multi-modality imaging necessary for procedural planning and patient selection. The heart team is critical in determining patient eligibility and benefit and the optimal operative approach for TAVR. The future of structural heart disease will certainly require a team approach, and the TAVR heart team will serve as the successful model.

Transcatheter aortic valve insertion (TAVI): a review

The introduction of transcatheter aortic valve insertion (TAVI) has transformed the care provided for patients with severe aortic stenosis. The uptake of this procedure is increasing rapidly, and clinicians from all disciplines are likely to increasingly encounter patients being assessed for or having undergone this intervention. Successful TAVI heavily relies on careful and comprehensive imaging assessment, before, during and after the procedure, using a range of modalities. This review outlines the background and development of TAVI, describes the nature of the procedure and considers the contribution of imaging techniques, both to successful intervention and to potential complications.

ACR appropriateness criteria imaging for transcatheter aortic valve replacement

Although aortic valve replacement is the definitive therapy for severe aortic stenosis, almost half of patients with severe aortic stenosis are unable to undergo conventional aortic valve replacement because of advanced age, comorbidities, or prohibitive surgical risk. Treatment options have been recently expanded with the introduction of catheter-based implantation of a bioprosthetic aortic valve, referred to as transcatheter aortic valve replacement. Because this procedure is characterized by lack of exposure of the operative field, image guidance plays a critical role in preprocedural planning. This guideline document evaluates several preintervention imaging examinations that focus on both imaging at the aortic valve plane and planning in the supravalvular aorta and iliofemoral system. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Standardized imaging for aortic annular sizing: implications for transcatheter valve selection

The safety and efficacy of transcatheter aortic valve replacement procedures are directly related to proper imaging. This report revisits the existing noninvasive and invasive approaches that have concurrently evolved to meet the demands for optimal selection and guidance of patients undergoing transcatheter aortic valve replacement. The authors summarize the published evidence and discuss the strengths and pitfalls of echocardiographic, computed tomographic, and calibrated aortic balloon valvuloplasty techniques in sizing the aortic valve annulus. Specific proposals for 3-dimensional tomographic reconstructions of complex 3-dimensional aortic root anatomy are provided for reducing intermodality variability in annular sizing. Finally, on the basis of the sizing approaches discussed in this review, the authors provide practical recommendations for balloon-expandable and self-expandable prostheses selection. Strategic use of echocardiographic, multislice computed tomographic, and angiographic data may provide complementary information for determining the anatomical suitability, efficacy, and safety of the procedure.

Sizing the aortic annulus

Transcatheter aortic valve implantation (TAVI) is a valuable alternative for aortic valve replacement in selected high-risk candidates. Accurate preoperative assessment of the aortic annular dimensions is crucial for the success of TAVI, since choice of an incorrectly sized prosthesis may result in catastrophic complications. These complications include annular rupture and coronary arterial obstruction, if the prosthesis is too big, or prosthesis migration and severe paravalvular leakage, if the prosthesis is too small. According to current recommendations, the choice of prosthesis size is based on transoesophageal echocardiography (TEE) measurements. However, TEE results are dependent on operator experience. Moreover, recent research has shown that TEE can significantly underestimate annular dimensional measurements. Alternative sizing methods based on Multidetector Computed Tomography (MDCT) or manometry during balloon aortic valvuloplasty have therefore been developed. We present a brief overview of the imaging modalities available for preoperative assessment of annular size and discuss their potential advantages and limitations.

Incidence, predictors, and outcomes of aortic regurgitation after transcatheter aortic valve replacement: meta-analysis and systematic review of literature

OBJECTIVES

This study was designed to establish the incidence, impact, and predictors of post-transcatheter aortic valve replacement (TAVR) aortic regurgitation (AR).

BACKGROUND

AR is an important limitation of TAVR with ill-defined predictors and unclear long-term impact on outcomes.

METHODS

Studies published between 2002 and 2012 with regard to TAVR were identified using an electronic search and reviewed using the random-effects model of DerSimonian and Laird. From 3,871 initial citations, 45 studies reporting on 12,926 patients (CoreValve [Medtronic CV Luxembourg S.a.r.l., Tolochenaz, Switzerland] n = 5,261 and Edwards valve [Edwards Lifesciences, Santa Ana, California] n = 7,279) were included in the analysis of incidence and outcomes of post-TAVR AR.

RESULTS

The pooled estimate for moderate or severe AR post-TAVR was 11.7% (95% confidence interval [CI]: 9.6 to 14.1). Moderate or severe AR was more common with use of the CoreValve (16.0% vs. 9.1%, p = 0.005). The presence of moderate or severe AR post-TAVR increased mortality at 30 days (odds ratio: 2.95; 95% CI: 1.73 to 5.02) and 1 year (hazard ratio: 2.27; 95% CI: -1.84 to 2.81). Mild AR was also associated with an increased hazard ratio for mortality, 1.829 (95% CI: 1.005 to 3.329) that was overturned by sensitivity analysis. Twenty-five studies reported on predictors of post-TAVR AR. Implantation depth, valve undersizing, and Agatston calcium score (r = 0.47, p = 0.001) were identified as important predictors.

CONCLUSIONS

Moderate or severe aortic regurgitation is common after TAVR and an adverse prognostic indicator of short- and long-term survival. Incidence of moderate or severe AR is higher with use of the CoreValve. Mild AR may be associated with increased long-term mortality. Therefore, every effort should be made to minimize AR by a comprehensive pre-procedural planning and meticulous procedural execution.

A practical guide to multimodality imaging of transcatheter aortic valve replacement

The advent of transcatheter aortic valve replacement (TAVR) is one of the most widely anticipated advances in the care of patients with severe aortic stenosis. This procedure is unique in many ways, one of which is the need for a multimodality imaging team-based approach throughout the continuum of the care of TAVR patients. Pre-procedural planning, intra-procedural implantation optimization, and long-term follow-up of patients undergoing TAVR require the expert use of various imaging modalities, each of which has its own strengths and limitations. Divided into 3 sections (pre-procedural, intraprocedural, and long-term follow-up), this review offers a single source for expert opinion and evidence-based guidance on how to incorporate the various modalities at each step in the care of a TAVR patient. Although much has been learned in the short span of time since TAVR was introduced, recommendations are offered for clinically relevant research that will lead to refinement of best practice strategies for incorporating multimodality imaging into TAVR patient care.

Time to revisit role of transcatheter balloon aortic valvuloplasty: a bridge-therapy to subsequent treatment case report

Recently there has been a noticeable resurgence in the usage of percutaneous balloon aortic valvuloplasty (BAV) by the development of less invasive endovascular therapies including transcatheter aortic valve implantation (TAVI). We performed BAV in a 91-year-old man with end-stage severe symptomatic aortic stenosis (AS) and an impending abdominal aortic aneurysm (AAA) rupture who had been refused surgical treatment because of the comorbidities with stage V chronic kidney disease (CKD) and severe left ventricular dysfunction. Improvement in hemodynamics and kidney function was observed after BAV. Subsequently, we performed endovascular aneurysm repair (EVAR) successfully for AAA using iodinated contrast. No deterioration of kidney function was confirmed after the procedure. The patient was discharged without any adverse events. At present, the possibilities of TAVI or surgical aortic valve replacement (s-AVR) are under consideration as the definitive therapy for the upcoming aortic valve restenosis. In conclusion, this inoperable patient with multiple comorbidities was successfully treated, at lower risk, by catheter-based two-stage therapy.

Multimodality imaging in transcatheter aortic valve implantation and post-procedural aortic regurgitation: comparison among cardiovascular magnetic resonance, cardiac computed tomography, and echocardiography

OBJECTIVES

The purpose of this study was to determine imaging predictors of aortic regurgitation (AR) after transcatheter aortic valve implantation (TAVI) and the agreement and reproducibility of cardiovascular magnetic resonance (CMR), cardiac computed tomography (CCT), and transthoracic echocardiography (TTE) in aortic root assessment.

BACKGROUND

The optimal imaging strategy for planning TAVI is unclear with a paucity of comparative multimodality imaging data. The association between aortic root morphology and outcomes after TAVI also remains incompletely understood.

METHODS

A total of 202 consecutive patients assessed by CMR, CCT, and TTE for TAVI were studied. Agreement and variability among and within imaging modalities was assessed by Bland-Altman analysis. Postoperative AR was assessed by TTE.

RESULTS

Of the 202 patients undergoing TAVI assessment with both CMR and TTE, 133 also underwent CCT. Close agreement was observed between CMR and CCT in dimensions of the aortic annulus (bias, -0.4 mm; 95% limits of agreement: -5.7 to 5.0 mm), and similarly for sinus of Valsalva, sinotubular junction, and ascending aortic measures. Agreement between TTE-derived measures and either CMR or CCT was less precise. Intraobserver and interobserver variability were lowest with CMR. The presence and severity of AR after TAVI were associated with larger aortic valve annulus measurements by both CMR (p = 0.03) and CCT (p = 0.04) but not TTE-derived measures (p = 0.10). Neither CCT nor CMR measures of annulus eccentricity, however, predicted AR after TAVI (p = 0.33 and p = 0.78, respectively).

CONCLUSIONS

In patients undergoing imaging assessment for TAVI, the presence and severity of AR after TAVI were associated with larger aortic annulus measurements by both CMR and CCT, but not TTE. Both CMR and CCT provide highly reproducible information in the assessment of patients undergoing TAVI.

Transcatheter aortic valve replacement: the changing paradigm of aortic stenosis treatment

Aortic stenosis is the most common cause for valvular surgery in the USA. For nearly 50 years, surgical aortic valve replacement has been the standard of care for symptomatic patients; unfortunately, a significant number of patients are not referred to surgery owing to advanced comorbidities and age. Transcatheter aortic valve replacement has emerged as an effective therapy for patients at high risk for surgery. Through device innovations and accumulated experience, the safety and efficacy of the procedure has improved since its inception. Transcatheter valve replacement has been found superior to medical therapy in inoperable patients with aortic stenosis, yet many questions remain as to which patients are appropriate for this exciting and novel therapy.

Correlates on MSCT of paravalvular aortic regurgitation after transcatheter aortic valve implantation using the Medtronic CoreValve prosthesis

BACKGROUND

To investigate the causes of paravalvular aortic regurgitation (PAR) after the implantation of the Medtronic CoreValve prosthesis (MCRS).

METHODS AND RESULTS

Fifty-six patients underwent MSCT before TAVI with a MCRS and PAR was assessed with transthoracic echocardiography (TTE) between 5 and 10 days after TAVI. The aortic annulus smallest and largest orthogonal diameters and the mean diameter from the area were determined on MSCT on an axial image at the nadir of all three native leaflets. PAR was related to relevant anatomical structures on MSCT according to a clockface in the orientation of the parasternal short axis view on TTE. PAR ≥ 1 was present in 25% of the patients and was associated with a larger annulus, a lower degree of over sizing and with more aortic root calcification. On MSCT post TAVI malapposition was seen predominantly at the aorto-mitral fibrous continuity and the aspect of the largest diameter of the aortic annulus on the inside curve of the ascending aorta. PAR was predominantly seen at these two anatomic locations and less frequent in the area that contains the ventricular membranous septum and the area between the non- and right coronary sinus.

CONCLUSIONS

Mild to moderate PAR is common after TAVI with the MCRS. The availability of additional (larger) prosthesis sizes in combination with improved sizing based on mean annulus diameter (e.g., D(CSA)) may help to reduce PAR.

Indication for percutaneous aortic valve implantation

The incidence of valvular aortic stenosis has increased over the past decades due to improved life expectancy. Surgical aortic valve replacement is currently the only treatment option for severe symptomatic aortic stenosis that has been shown to improve survival. However, up to one third of patients who require lifesaving surgical aortic valve replacement are denied surgery due to high comorbidities resulting in a higher operative mortality rate. In the past such patients could only be treated with medical therapy or percutaneous aortic valvuloplasty, neither of which has been shown to improve mortality. With advances in interventional cardiology, transcatheter methods have been developed for aortic valve replacement with the goal of offering a therapeutic solution for patients who are unfit for surgical therapy. Currently there are two catheter-based treatment systems in clinical application (the Edwards SAPIEN aortic valve and the CoreValve ReValving System), utilizing either a balloon-expandable or a self-expanding stent platform, respectively.

Multimodal assessment of the aortic annulus diameter: implications for transcatheter aortic valve implantation

OBJECTIVES

We sought to compare 3 methods of measurements of the aortic annulus, transthoracic echocardiography (TTE), transesophageal echocardiography (TEE), and multislice computed tomography (MSCT), and to evaluate their potential clinical impact on transcatheter aortic valve implantation (TAVI) strategy.

BACKGROUND

Exact measurement of the aortic annulus is critical for a patient's selection and successful implantation.

METHODS

Annulus diameter was measured using TTE, TEE, and MSCT in 45 consecutive patients with severe aortic stenosis referred for TAVI. The TAVI strategy (decision to implant and choice of the prosthesis' size) was based on manufacturer's recommendations (Edwards-Sapien prosthesis, Edwards Lifesciences, Inc., Irvine, California).

RESULTS

Correlations between methods were good but the difference between MSCT and TTE (1.22 +/- 1.3 mm) or TEE (1.52 +/- 1.1 mm) was larger than the difference between TTE and TEE (0.6 +/- 0.8 mm; p = 0.03 and p < 0.0001, respectively). Regarding TAVI strategy, agreement between TTE and TEE overall was good (kappa = 0.68), but TAVI strategy would have been different in 8 patients (17%). Agreement between MSCT and TTE or TEE was only modest (kappa = 0.28 and 0.27), and a decision based on MSCT measurements would have modified the TAVI strategy in a large number of patients (40% to 42%). Implantation, performed in 34 patients (76%) based on TEE measurements, was successful in all but 1 patient with grade 3/4 regurgitation.

CONCLUSIONS

In patients referred for TAVI, measurements of the aortic annulus using TTE, TEE, and MSCT were close but not identical, and the method used has important potential clinical implications on TAVI strategy. In the absence of a gold standard, a strategy based on TEE measurements provided good clinical results.

Determinants of significant paravalvular regurgitation after transcatheter aortic valve: implantation impact of device and annulus discongruence

OBJECTIVES

The aim of this study was to assess prosthesis/annulus discongruence and its impact on the occurrence of significant aortic regurgitation (AR) immediately after transcatheter aortic valve implantation (TAVI).

BACKGROUND

Paravalvular AR might occur after TAVI, but its determinants remain unclear.

METHODS

Comprehensive echocardiographic examinations were performed in 74 patients who underwent TAVI with a balloon expandable device. Congruence between annulus and device was appraised with the cover index: 100 x (prosthesis diameter - transesophageal echocardiography annulus diameter)/prosthesis diameter.

RESULTS

At baseline aortic valve area was 0.67 +/- 0.2 cm(2), and mean gradient was 50 +/- 15 mm Hg. The TAVI used transfemoral approach in 46 patients (62%) and transapical access in 28 (38%). Prosthesis size was 23 mm in 24 patients (34%) and 26 mm in 50 patients (66%). After TAVI, paravalvular AR was absent in 5 patients (7%), graded 1/4 in 53 (72%), 2/4 in 12 (16%), and 3/4 in 4 (5%). Occurrence of AR >or=2/4 was related to greater patient height, larger annulus, and smaller cover index (all p < 0.002) but not to ejection fraction, severity of stenosis, or prosthesis size. AR >or=2/4 was never observed in patients with aortic annulus <22 mm or with a cover index >8%. Significant improvements were observed from the first 20 cases (AR >or=2/4, 40%) to the last 54 (AR >or=2/4, 15%) (p = 0.02). In multivariate analysis, independent predictors of AR >/=2/4 were low cover index (odds ratio: 1.22; per confidence interval: 1.03 to 1.51 per 1% decrease, p = 0.02) and first versus last procedures (odds ratio: 2.24; 95% confidence interval: 1.07 to 5.22, p = 0.03).

CONCLUSIONS

Our study shows that the occurrence of AR >or=2/4 is related to prosthesis/annulus discongruence even after adjustment for experience. Hence, to minimize paravalvular AR, appropriate annular measurements and prosthesis sizing are critical.