Utility of Three-Dimensional (3D) Modeling for Planning Structural Heart Interventions (with an Emphasis on Valvular Heart Disease)

PURPOSE OF REVIEW

Advanced imaging has played a vital role in the contemporary, rapid rise of structural heart interventions. 3D modeling and printing has emerged as one of the most recent imaging tools and the implementation of 3D modeling is expected to increase with further advances in imaging, print hardware, and materials.

RECENT FINDINGS

3D modeling can be used to educate patients and clinical teams, provide ex vivo procedural simulation, and improve outcomes. Intra-procedural success rates may be improved, and post-procedural complications can be predicted more robustly with appropriate application of 3D modeling. Recent advances in technology have increased the availability of this tool, such that there can be more ready adoption into a routine clinical workflow. Familiarity with 3D modeling and its current utilization and role in structural interventions will help inform how to approach and adapt this exciting new technology.

How valvular calcification can affect the outcomes of transcatheter aortic valve implantation

Introduction In transcatheter aortic valve implantation (TAVI), assessment of aortic valve calcification is not as standardized as aortic annulus measurement. Aortic valve calcification is important for stable anchoring of the prosthesis to the aortic annulus. However, excessive aortic valve calcification is related to procedural complications. Areas covered This review covers the methods to assess aortic valve calcification and the implications of aortic valve calcium burden for TAVI outcomes. We performed a systematic review of the literature in Pubmed and secondary sources. Furthermore, future perspectives on how to integrate aortic valve calcification assessment in the management of patients with aortic stenosis is discussed. Expert opinion Thorough assessment of the aortic valve and aortic root components including aortic valve calcification is key in the planning of TAVI. Aortic valve calcification load, location and extension are important contributors to paravalvular regurgitation. Asymmetric calcification burden with greater calcification of the left-coronary cusp related to higher need of permanent pacemaker implantation. Patients with moderate and severe left ventricular outflow tract/subannular calcification are more susceptible to aortic annular rupture. Periprocedural dislodgement of calcium form cusps and commissures is one of the main reasons of coronary artery ostial occlusion during transcatheter aortic valve implantation. Abbreviations Ao, aorta; LA, left atrium; LAA, left atrial appendage; LV, left ventricle; LVOT, left ventricular outflow tract; THV, transcatheter heart valve.

Aortic Valve Calcification as a Predictor of Post-Transcatheter Aortic Valve Replacement Pacemaker Dependence

Background

Atrioventricular block requiring permanent pacemaker (PPM) implantation is a common complication of transcatheter aortic valve replacement (TAVR). The mechanism of atrioventricular (AV) block during TAVR is not fully understood, but it may be due to the mechanical stress of TAVR deployment, resulting in possible injury to the nearby compact AV node. Aortic valve calcification (AVC) may worsen this condition and has been associated with an increased risk for post-TAVR PPM implantation. We performed a retrospective analysis to determine if AVC is predictive for long-term right ventricular (RV) pacing in post-TAVR pacemaker patients at 30 days.

Methods

A total of 262 consecutive patients who underwent TAVR with a balloon-expandable valve were analyzed. AVC data were derived from contrast-enhanced computed tomography and characterized by leaflet sector and region.

Results

A total of 25 patients (11.1%) required post-TAVR PPM implantation. Seventeen patients did not require RV pacing at 30 days. Nine of these 17 patients had no RV pacing requirement within 10 days. The presence of intra-procedural heart block (P = 0.004) was the only significant difference between patients who did not require PPM and those who required PPM but they were not RV pacing-dependent at 30 days. Non-coronary cusp (NCC) calcium volume was significantly higher in patients who were pacemaker-dependent at 30 days (P = 0.01) and a calcium volume of > 239.2 mm³ in the NCC was strongly predictive of pacemaker dependence at 30 days (area under the curve (AUC) = 0.813). Pre-existing right bundle branch block (RBBB) (odds ratio (OR) 105.4, P = 0.004), bifascicular block (OR 12.5, P = 0.02), QRS duration (OR 70.43, P = 0.007) and intra-procedural complete heart block (OR 12.83, P = 0.03) were also predictive of pacemaker dependence at 30 days.

Conclusions

In patients who required PPM after TAVR, quantification of AVC by non-coronary leaflet calcium volume was found to be a novel predictor for RV pacing dependence at 30 days. The association of NCC calcification and PPM dependence may be related to the proximity of the conduction bundle to the non-coronary leaflet. Further studies are necessary to improve risk prediction for long-term RV pacing requirements following TAVR.

3D Printing Applications for Transcatheter Aortic Valve Replacement

PURPOSE OF REVIEW

A combination of evolving 3D printing technologies, new 3D printable materials, and multi-disciplinary collaborations have made 3D printing applications for transcatheter aortic valve replacement (TAVR) a promising tool to promote innovation, increase procedural success, and provide a compelling educational tool. This review synthesizes the knowledge via publications and our group's experience in this area that exemplify uses of 3D printing for TAVR.

RECENT FINDINGS

Patient-specific 3D-printed models have been used for TAVR pre-procedural device sizing, benchtop prediction of procedural complications, planning for valve-in-valve and bicuspid aortic valve procedures, and more. Recent publications also demonstrate how 3D printing can be used to test assumptions about why certain complications occur during THV implantation. Finally, new materials and combinations of existing materials are starting to bridge the large divide between current 3D material and cardiac tissue properties. Several studies have demonstrated the utility of 3D printing in understanding challenges of TAVR. Innovative approaches to benchtop testing and multi-material printing have brought us closer to being able to predict how a THV will interact with a specific patient's aortic anatomy. This work to date is likely to open the door for advancements in other areas of structural heart disease, such as interventions involving the mitral valve, tricuspid valve, and left atrial appendage.

CT in planning transcatheter aortic valve implantation procedures and risk assessment

For surgical aortic valve replacement, the Society of Thoracic Surgeons score (STSS) is the reference standard for the prediction of operative risk. In transcatheter aortic valve implantation (TAVI) though, where the procedure itself is minimally invasive, the traditional risk assessment is supplemented by CTA. Through a consistent approach to the acquisition of high-quality images and the standardised reporting of annular measurements and adverse root and vascular features, patients at risk of complications can be identified. In turn, this may allow for a personalised procedural approach and treatment strategies devised to potentially reduce or mitigate this risk. This article provides a systematic and standardised approach to pre-procedural work-up with computed tomography angiography (CTA) and explores the current state of evidence and future areas of development in this rapidly developing field.

Late ventricular standstill following an elective TAVI

Transcatheter aortic valve implantations (TAVIs) may be complicated by a need for permanent pacemaker implantation post procedure, usually due to local trauma or compression on the conduction system. There are some features that might help predict that a patient is high risk for developing conduction disease following TAVI, for example, underlying right bundle branch block or use of certain types of TAVI. It might also become apparent during the procedure, or before temporary wire removal post procedure. Higher risk patients may undergo rhythm monitoring for longer periods post TAVI. We present a case where a patient required an unexpected emergency pacemaker following a TAVI, despite low risk clinical features, a low risk baseline ECG, and the use of a low risk TAVI valve. In addition, this very significant conduction disease only became apparent over 72 hours following implantation, despite normal resting ECGs and telemetry up to that point.

Impact of postprocedural permanent pacemaker implantation on clinical outcomes after transcatheter aortic valve replacement: a systematic review and meta-analysis

Background

The incidence of conduction disturbances requiring permanent pacemaker (PPM) implantation following transcatheter aortic valve replacement (TAVR) have remained a common concern. The purpose of this study was to evaluate the impact of postprocedural PPM implantation following TAVR on clinical outcomes.

Methods

We performed a systematic search in PubMed and EMBASE databases for studies that reported raw data on clinical outcomes of patients with and without PPM implantation after TAVR and followed up patients for 10 months or longer. The primary endpoint was all-cause death. The secondary endpoints were cardiovascular death, heart failure and a composite of stroke and myocardial infarction (MI).

Results

Data from 20 studies with a total of 21,666 patients undergoing TAVR, of whom 12.5% required PPM implantation after intervention, were analysed and the mean duration follow-up was 16.9 months. The rate of PPM ranged from 6.2% to 32.8% among different studies. A total of 6,753 (31.2%) patients underwent TAVR with self-expandable prosthesis and 14,913 (68.8%) with balloon-expandable prosthesis. The incidence of postprocedural PPM implantation was higher with the self-expandable prosthesis (n=1,717, 25.4%) compared with the balloon-expandable prosthesis (n=996, 6.7%). PPM after TAVR was associated with a higher risk of all-cause death (RR: 1.13; 95% CI: 1.01-1.25; P=0.03) but not incidence of stroke and MI (RR: 0.85; 95% CI: 0.64-1.13; P=0.27).

Conclusions

In patients undergoing TAVR, the PPM implantation after intervention was associated higher all-cause mortality but not cardiovascular mortality, heart failure and stroke or MI, which remain an unsolved issue of TAVR.

Impact of Aortomitral Continuity Calcification on Need for Permanent Pacemaker After Transcatheter Aortic Valve Replacement

Background:

By virtue of its proximity to structures vital to cardiac conduction, aortomitral continuity calcification (AMCC) may help identify patients at highest risk for developing atrioventricular conduction disease requiring permanent pacemaker implantation (PPMI). We aim to determine the association of AMCC and need for PPMI after transcatheter aortic valve replacement.

Methods:

Of 614 patients who underwent transcatheter aortic valve replacement (11.8% PPMI rate), we included 136 patients (age 85±8 years, 47% male) without a preexisting intracardiac device or prior valve surgery who underwent preprocedural computed tomography. We analyzed for the presence of AMCC, aortic valve calcification, and mitral annular calcification as well as quantified AMCC and aortic valve calcification score using the Agatston method. We further stratified AMCC score into 3 categories: 0, 1 to 300, and >300. End point was PPMI at 1 month after transcatheter aortic valve replacement.

Results:

There were 51 (38%) new PPMIs (median time to PPMI, 5 days). Patients who underwent PPMI had a higher prevalence of AMCC than patients without PPMI (69% versus 32%; P <0.0001), as well as higher median AMCC score (263 versus 0; P <0.0001). There was no difference in aortic valve calcification and mitral annular calcification between patients with and without PPMI (all P ≥0.09). Patients with AMCC had a 4-fold increase in odds for PPMI compared with those without (adjusted odds ratio, 4.0; P =0.0026). Compared with patients with an AMCC score of 0, patients with an AMCC score >300 had greater than a 5-fold increased odds for PPMI (adjusted odds ratio, 5.7; P =0.0016).

Conclusions:

Presence of AMCC, particularly with AMCC score >300, is associated with the need for PPMI after transcatheter aortic valve replacement.

Should All Low-risk Patients Now Be Considered for TAVR? Operative Risk, Clinical, and Anatomic Considerations

PURPOSE OF REVIEW

This article reviews the current data on TAVR in low-risk patients with severe, symptomatic aortic stenosis, highlights the results of the recently published Medtronic Low Risk Randomized Study and PARTNER 3 trials, and describes specific clinical, anatomic, and procedural considerations regarding the optimal treatment choice in this population.

RECENT FINDINGS

In low-risk patients, the Medtronic Low Risk Randomized Study demonstrated TAVR to be non-inferior to surgery with respect to the composite endpoint of death or disabling stroke while PARTNER 3 trial proved TAVR to be superior to surgery with regard to the composite endpoint of death, stroke, or rehospitalization. Recent trials demonstrate the safety and efficacy of TAVR in low-risk patients and have led to an FDA indication for the use of TAVR in these patients. However, the lack of long-term data on the rate of transcatheter valve deterioration in the younger population, higher incidence of paravalvular leak and pacemaker implantation following TAVR, along with certain intrinsic anatomic factors remain potential challenges to generalize TAVR in all low surgical risk patients. We describe specific clinical, anatomic, and procedural considerations regarding the optimal treatment choice for low-risk patients with severe, symptomatic AS.

[Transcatheter aortic valve implantation and conduction disturbances]

Transcatheter aortic valve implantation (TAVI) is currently becoming the treatment of choice for patients with calcific aortic stenosis. Despite several technical improvements, the incidence of conduction disturbances has not diminished and remains TAVI's major complication. These disturbances include the occurrence of left bundle branch block and/or high-grade atrioventricular block often requiring pacemaker implantation. The proximity of the aortic valve to the conduction system (conduction pathways) accounts for the occurrence of these complications. Several factors have been identified as carrying a high risk of conduction disturbances like the presence of pre-existing right bundle branch block, the type of valve implanted, the volume of aortic and mitral calcifications, the size of the annulus and the depth of valve implantation. Left bundle branch block is the most frequent post TAVI conduction disturbance. Whereas the therapeutic strategy for persistent complete atrioventricular block is simple, it becomes complex in the presence of fluctuating changes in PR interval and left bundle branch block duration. The QRS width threshold value (150-160 ms) indicative of the need for pacemaker implantation is still being debated. Although there are currently no recommendations regarding the management of these conduction disturbances, the extension of TAVI indications to patient at low surgical risk calls for a standardization of our practice. However, a decision algorithm was recently proposed by a group of experts composed of interventional cardiologists, electrophysiologists and cardiac surgeons. There are still uncertainties about the appropriate timing of pacemaker implantation and the management of new onset left bundle branch block.

Three-Dimensional Printing Applications in Percutaneous Structural Heart Interventions

Cardiovascular 3-dimensional printing refers to the fabrication of patients’ specific cardiac anatomic replicas based on volumetric imaging data sets obtained by echocardiography, computed tomography, or magnetic resonance imaging. It enables advanced visualization and enhanced anatomic and sometimes hemodynamic understanding and also improves procedural planning and allows interventional simulation. Also, it is helpful in communication with patients and trainees. These key advantages have led to its broad use in the field of cardiology ranging from congenital to vascular and valvular disease, particularly in structural heart interventions, where many emerging technologies are being developed and tested. This review summarizes the process of 3-dimensional printing and the workflow from imaging acquisition to model generation and discusses the cardiac applications of 3-dimensional printing focusing on its use in percutaneous structural interventions, where procedural planning now commonly relies on 3-dimensional printed models.

Early Real-World Experience with CoreValve Evolut PRO and R Systems for Transcatheter Aortic Valve Replacement

OBJECTIVES

The purpose of this study was to compare the efficacy and safety of the Evolut PRO to the Evolut R valve in a real-world setting.

BACKGROUND

The next-generation self-expanding transcatheter aortic valve replacement (TAVR) system, the CoreValve Evolut PRO was designed with an outer pericardial skirt to improve valve-sealing performance. Safety and efficacy of this valve have not previously been compared to its predecessor, the Evolut R valve.

METHODS

We retrospectively studied 134 patients who underwent TAVR with the Evolut PRO or Evolut R valve over one year at a tertiary center. Endpoints, defined by the Valve Academic Research Consortium-2 criteria, included device success, paravalvular leak (PVL), and a composite safety endpoint including mortality, stroke, major vascular complications, life-threatening bleeding, acute kidney injury, coronary artery obstruction, and repeat procedure for valve-related dysfunction.

RESULTS

60 Evolut PRO and 56 Evolut R patients met the study criteria. Both groups had similar device success rates (90 vs. 89%, p=0.44). Incidence of moderate PVL was similar on discharge (5 vs. 11%, p=0.68) and at 30 days (11 vs. 13%, p=0.79), with nil incidence of severe PVL. There were no mortalities, and the VARC-2 safety endpoint at 30 days was comparable.

CONCLUSION

Despite the additional pericardial skirt and larger sheath size of Evolut PRO, outcomes were comparable between the two Evolut systems, supporting adoption of the newest generation valve in the management of severe aortic stenosis as well as continued use of the Evolut R in patients with smaller vasculature warranting a lower profile device.

Utility of computed tomography in cases of aortic valve stenosis before and after transcatheter aortic valve implantation

Trans-catheter aortic valve implantation (TAVI) has been recognized as a useful treatment for patients with severe aortic valve stenosis, particularly those with moderate to high risks of open heart surgery. A thorough evaluation of the aortic valve complex, including the size or presence of calcifications of the leaflets and annulus, is important for the selection of appropriate candidates, artificial valve types and approach. Echocardiography is useful for the precise evaluation of aortic valve stenosis severity and aortic valve complex morphology, but it is not useful to evaluate three-dimensional aortic valve anatomy and pathway for the catheter of aortic valve implantation. Electrocardiography (ECG)-gating computed tomography (CT) has recently been recognized as a useful modality for evaluating significant coronary artery stenosis because of its higher spatial and temporal resolution and diagnostic accuracy based on recent studies. ECG-gating CT is also useful for evaluating aortic valve complex morphology, including calcifications and whole aorta and iliac arteries, as the access route of catheter in TAVI. TAVI candidates, who are at high risk of open surgery, tend to be old and require anti-platelet after TAVI; therefore CT, is also useful for screening for non-cardiac diseases including malignant tumors just before TAVI. Therefore, here we introduce the utility of cardiac and whole body CT in cases of severe aortic valve stenosis before and after TAVI.

The Impact of Size and Position of a Mechanical Expandable Transcatheter Aortic Valve: Novel Insights Through Computational Modelling and Simulation

Transcatheter aortic valve implantation has become an established procedure to treat severe aortic stenosis. Correct device sizing/positioning is crucial for optimal outcome. Lotus valve sizing is based upon multiple aortic root dimensions. Hence, it often occurs that two valve sizes can be selected. In this study, patient-specific computer simulation is adopted to evaluate the influence of Lotus size/position on paravalvular aortic regurgitation (AR) and conduction abnormalities, in patients with equivocal aortic root dimensions. First, simulation was performed in 62 patients to validate the model in terms of predicted AR and conduction abnormalities using postoperative echocardiographic, angiographic and ECG-based data. Then, two Lotus sizes were simulated at two positions in patients with equivocal aortic root dimensions. Large valve size and deep position were associated with higher contact pressure, while only large size, not position, significantly reduced the predicted AR. Despite general trends, simulations revealed that optimal device size/position is patient-specific.

Transvascular transcatheter aortic valve implantation in 2017

BACKGROUND

Transcatheter aortic valve implantation (TAVI) is emerging as the standard of care for patients with severe aortic stenosis. Recent results have been favourable even for patients with low periprocedural risk.

METHODS

We analysed the number of procedures, complications, and in-hospital mortality rates of all patients undergoing isolated aortic valve replacement in 2017 in Germany, focussing especially on transvascular (TV) TAVI. Patients were stratified according the German Aortic Valve Score (AKL) into the risk classes low, intermediate, high and very high (≥ 10%).

RESULTS

A total of 17,956 TV-TAVI and 9011 isolated surgical aortic valve replacements (iSAVR) were performed in Germany in 2017. Although the total rate of intraprocedural complications after TV-TAVI was the same as in 2016 (both 7.4%), fewer patients experienced an arterial vascular complication in 2017 (2017: 6.0%; 2016: 7.1%; p < 0.001). Likewise, the rate of new pacemaker implantation decreased (2017: 9.6%; 2016:11.4%; p < 0.001). In-hospital mortality after TV-TAVI and iSAVR was equal (2.7%) in 2017, despite the much higher risk profile of TV-TAVI patients. Using the AKL score as reference, TV-TAVI showed a more favourable observed-to-expected mortality (O/E) ratio (0.89) than iSAVR (1.14)- even more pronounced in patients at low risk (0.81 vs. 1.14).

CONCLUSIONS

The rates of major complications like bleeding and permanent pacemaker implantation after TV-TAVI keep declining. In 2017 patients undergoing TV-TAVI had a low in-hospital mortality rate with an O/E ratio < 1, indicating that the results were again better than those of all TAVI and SAVR of the previous year. Overall in-hospital mortality after transvascular TAVI and isolated aortic valve repair 2017 in Germany stratified to risk groups by the German Aortic Valve Score (German AV Score/AKL Score): low risk group (AKL 0- < 3%), intermediate risk group (AKL 3- < 6%), high risk group (AKL 6- < 10%) and very high risk group (AKL ≥ 10%).

Detection and Prediction of Bioprosthetic Aortic Valve Degeneration

BACKGROUND

Bioprosthetic aortic valve degeneration is increasingly common, often unheralded, and can have catastrophic consequences.

OBJECTIVES

The authors sought to assess whether 18F-fluoride positron emission tomography (PET)-computed tomography (CT) can detect bioprosthetic aortic valve degeneration and predict valve dysfunction.

METHODS

Explanted degenerate bioprosthetic valves were examined ex vivo. Patients with bioprosthetic aortic valves were recruited into 2 cohorts with and without prosthetic valve dysfunction and underwent in vivo contrast-enhanced CT angiography, 18F-fluoride PET, and serial echocardiography during 2 years of follow-up.

RESULTS

All ex vivo, degenerate bioprosthetic valves displayed 18F-fluoride PET uptake that colocalized with tissue degeneration on histology. In 71 patients without known bioprosthesis dysfunction, 14 had abnormal leaflet pathology on CT, and 24 demonstrated 18F-fluoride PET uptake (target-to-background ratio 1.55 [interquartile range (IQR): 1.44 to 1.88]). Patients with increased 18F-fluoride uptake exhibited more rapid deterioration in valve function compared with those without (annualized change in peak transvalvular velocity 0.30 [IQR: 0.13 to 0.61] vs. 0.01 [IQR: -0.05 to 0.16] ms-1/year; p < 0.001). Indeed 18F-fluoride uptake correlated with deterioration in all the conventional echocardiographic measures of valve function assessed (e.g., change in peak velocity, r = 0.72; p < 0.001). Each of the 10 patients who developed new overt bioprosthesis dysfunction during follow-up had evidence of 18F-fluoride uptake at baseline (target-to-background ratio 1.89 [IQR: 1.46 to 2.59]). On multivariable analysis, 18F-fluoride uptake was the only independent predictor of future bioprosthetic dysfunction.

CONCLUSIONS

18F-fluoride PET-CT identifies subclinical bioprosthetic valve degeneration, providing powerful prediction of subsequent valvular dysfunction and highlighting patients at risk of valve failure. This technique holds major promise in the diagnosis of valvular degeneration and the surveillance of patients with bioprosthetic valves. (18F-Fluoride Assessment of Aortic Bioprosthesis Durability and Outcome [18F-FAABULOUS]; NCT02304276).

3D printing approaches for cardiac tissue engineering and role of immune modulation in tissue regeneration

Conventional tissue engineering, cell therapy, and current medical approaches were shown to be successful in reducing mortality rate and complications caused by cardiovascular diseases (CVDs). But still they have many limitations to fully manage CVDs due to complex composition of native myocardium and microvascularization. Fabrication of fully functional construct to replace infarcted area or regeneration of progenitor cells is important to address CVDs burden. Three-dimensional (3D) printed scaffolds and 3D bioprinting technique have potential to develop fully functional heart construct that can integrate with native tissues rapidly. In this review, we presented an overview of 3D printed approaches for cardiac tissue engineering, and advances in 3D bioprinting of cardiac construct and models. We also discussed role of immune modulation to promote tissue regeneration.

3D printing for heart valve disease: a systematic review

BACKGROUND

Current developments showed a fast-increasing implementation and use of three-dimensional (3D) printing in medical applications. Our aim was to review the literature regarding the application of 3D printing to cardiac valve disease.

METHODS

A PubMed search for publications in English with the terms "3D printing" AND "cardiac valve", performed in January 2018, resulted in 64 items. After the analysis of the abstract and text, 27 remained related to the topic. From the references of these 27 papers, 7 papers were added resulting in a total of 34 papers. Of these, 5 were review papers, thus reducing the papers taken into consideration to 29.

RESULTS

The 29 papers showed that about a decade ago, the interest in 3D printing for this application area was emerging, but only in the past 2 to 3 years it really gained interest. Computed tomography is the most common imaging modality taken into consideration (62%), followed by ultrasound (28%), computer-generated models (computer-aided design) (7%), and magnetic resonance imaging (3%). Acrylonitrile butadiene styrene (4/14, 29%) and TangoPlus FullCure 930 (5/14, 36%) are the most used printing materials. Stereolithography (40%) and fused deposition modeling (30%) are the preferred printing techniques, while PolyJet (25%) and laser sintering (4%) are used in a minority of cases. The reported time ranges from 30 min to 3 days. The most reported application area is preoperative planning (63%), followed by training (19%), device testing (11%), and retrospective procedure evaluation (7%).

CONCLUSIONS

In most cases, CT datasets are used and models are printed for preoperative planning.

Underfilled Balloon-Expandable Transcatheter Aortic Valve Implantation With Ad Hoc Post-Dilation - Pulsatile Flow Simulation Using a Patient-Specific Three-Dimensional Printing Model

BACKGROUND

Underfilled transcatheter aortic-valve implantation with ad hoc post-dilation is a therapeutic option for patients with borderline annuli to avoid acute complication. The effects of this technique on valve leaflet behavior, hydrodynamic performances, and paravalvular leakage (PVL) using patient-specific three-dimensional (3D) aortic-valve models were investigated. Methods and Results: A female octogenarian patient was treated with this technique by using a 23-mm Sapien-XT. Patient-specific models were constructed from pre-procedure computed tomography (CT) data. Change in aortic annulus areas during systolic/diastolic phases and post-procedure stent areas were adjusted to those of the patient. The following was performed: (1) -3 cc initial and -2 cc underfilled post-dilation to the scale-down model by adjusting percent oversizing; and (2) -1 cc initial underfilling, nominal volume, and repeat nominal volume post-dilation using the patient-specific model. Underfilling was associated with higher %PVL. Observation using a high-speed camera revealed distorted leaflets after underfilled implantation, with a longer valve-closing time and smaller effective orifice areas, especially in the -3 cc underfilled implantation. Micro-CT analysis revealed that the transcatheter valves shifted to the opposite side of the large annulus calcification after post-dilation and reduced the malapposition there.

CONCLUSIONS

Excessive underfilled implantation showed unacceptable acute hemodynamics. Abnormal leaflet motions after underfilled implantation raised concerns about durability. Flow simulations using patient-oriented 3D models could help to investigate hemodynamics, leaflet motions, and the PVL mechanism.

Delayed pacemaker requirement after transcatheter aortic valve implantation with a new-generation balloon expandable valve: Should we monitor longer?

OBJECTIVES

To analyze the timing of appearance of conduction abnormalities (CAs) after transcatheter aortic valve implantation (TAVI), to identify predictors of delayed CAs requiring pacemaker (PM) implantation and to provide guidance regarding the duration of telemetry monitoring.

BACKGROUND

How long patients remain at risk of development of CAs requiring PM implantation after TAVI and for how long they should be monitored remains unclear but is crucial when considering early discharge.

METHODS

Development of CAs was studied in 701 consecutive patients treated with Edwards Sapien 3 valves and monitored with telemetry for 7 days in a single center. After excluding valve-in-valve procedures and patients with previous PM, 606 patients remained for analysis. Predictors of CAs requiring PM and the time of onset of CAs were analyzed.

RESULTS

Of 606 patients 76 (12.5%) required a PM after TAVI. CAs requiring PM implantation occurred after 48 h in 22.4% (17 patients) and in 10.5% (8 patients) even after 5 days. Of the patients who developed high grade CAs requiring PM after 48 h, 47.1% had no CAs prior to TAVI, and 23.5% had neither pre-existing CAs nor new-developed CAs within the first 48 h after TAVI.

CONCLUSION

After TAVI using a new-generation balloon-expandable valve, delayed development of CAs requiring PM implantation is not uncommon, even after 5 days. More importantly, 23.5% of patients eventually requiring a delayed PM implantation had still no CAs at 48 h after TAVI in this study. These results question the safety of early discharge and support ECG monitoring for a longer time period. The most optimal way to monitor these patients is yet to be determined.

The Various Applications of 3D Printing in Cardiovascular Diseases

PURPOSE OF REVIEW

To highlight the various applications of 3D printing in cardiovascular disease and discuss its limitations and future direction.

RECENT FINDINGS

Use of handheld 3D printed models of cardiovascular structures has emerged as a facile modality in procedural and surgical planning as well as education and communication. Three-dimensional (3D) printing is a novel imaging modality which involves creating patient-specific models of cardiovascular structures. As percutaneous and surgical therapies evolve, spatial recognition of complex cardiovascular anatomic relationships by cardiologists and cardiovascular surgeons is imperative. Handheld 3D printed models of cardiovascular structures provide a facile and intuitive road map for procedural and surgical planning, complementing conventional imaging modalities. Moreover, 3D printed models are efficacious educational and communication tools. This review highlights the various applications of 3D printing in cardiovascular diseases and discusses its limitations and future directions.

Computed tomography predictors of mortality, stroke and conduction disturbances in women undergoing TAVR: A sub-analysis of the WIN-TAVI registry

BACKGROUND

Aortic valve calcification patterns were associated with short- and long-term outcomes in previous small observational datasets of patients undergoing transcatheter aortic valve implantation (TAVI). The specific impact of multi detector-row computed tomography (MDCT) findings on outcomes in women has not been reported. We sought to describe the associations between MDCT characteristics and clinical outcomes in a registry of 547 women undergoing TAVI.

METHODS

WIN-TAVI is the first all-female registry to study the safety and effectiveness of TAVI in women (n = 1019). Thirteen sites participated in the MDCT sub-study and contributed pre-TAVI MDCT studies in 547 consecutive subjects. All MDCT data were analyzed in an independent core lab blinded to clinical outcomes. Key measurements included number of valve leaflets, aortic annulus area and perimeter, left and right coronary artery height, aortic cusp calcium volume, commissural calcification and left ventricular outflow tract (LVOT) calcification. Calcium volume of the aortic valvular complex was quantified using a threshold relative to patient-specific contrast attenuation in the arterial blood pool. We examined univariate and multivariate associations between ECG-gated contrast MDCT characteristics and 1-year mortality or stroke, new pacemaker implantation and new onset atrial fibrillation (AF).

RESULTS

The CT sub-study sample had a mean age of 82.8 ± 6.3 years, mean logistic EuroSCORE of 17.8 ± 11.3%, and mean STS score of 8.2 ± 7.4%. Transfemoral access was used in 89.6% of patients. After multivariate adjustment, moderate or severe LVOT calcification was an independent predictor of 1-year mortality or stroke (HR = 1.91; 95% CI: 1.11-3.30; p = 0.02). Calcium volume in the right coronary cusp was an independent predictor of new pacemaker (HR = 1.18 per 100 m³ increment; p = 0.04), whereas calcium volume of the non-coronary cusp had a protective effect (HR = 0.78 per 100 mm³ increment; p = 0.004). Severe calcification of the non-coronary/right-coronary commissure was an independent predictor of new AF (HR = 5.1; p = 0.008).

CONCLUSION

Computed tomography provides important prognostic information in women undergoing TAVI. Moderate or severe LVOT calcification is associated to an almost two-fold increased risk of mortality or stroke at one year. Different calcification patterns of the aortic valve may predict diverse rhythm abnormalities.

Atrial fibrillation in patients undergoing transcatheter aortic valve implantation: epidemiology, timing, predictors, and outcome

Atrial fibrillation (AF) is a common arrhythmia in patients with aortic stenosis. When these patients are treated medically or by surgical aortic valve replacement, AF is associated with increased risk of adverse events including death. Growing evidence suggests a significant impact of AF on outcomes also in patients with aortic valve stenosis undergoing transcatheter aortic valve implantation (TAVI). Conversely, limited evidence is available regarding the optimal management of this condition. This review aims to summarize prevalence, pathophysiology, prognosis, and treatment of AF in patients undergoing TAVI.

Comparative analysis of balloon- versus mechanically-expandable transcatheter heart valves considering landing zone calcification

BACKGROUND

The balloon-expandable Sapien 3 (Edwards Lifesciences, Irvine, CA, USA) and the mechanically-expandable Lotus valve (Boston Scientific, Marlborough, MA, USA) are established devices for transcatheter aortic valve implantation. We sought to compare both transcatheter heart valves (THV) under consideration of the extent of THV landing zone calcification.

METHODS

This retrospective analysis includes consecutive patients with severe aortic stenosis treated with Sapien 3 (S3; n=212) or Lotus (n=61) THV via transfemoral access. Outcome was assessed according to VARC II definitions. Rate of paravalvular leakage (PVL), periprocedural stroke, and permanent pacemaker implantation (PPI) was adjusted for THV landing zone calcification as calculated by multi-slice computed tomography.

RESULTS

There was no difference in preoperative risk (all results as follows S3 vs. Lotus: STS-PROM 5.9±5.6% vs. 4.8±2.6%, p=0.14), rate of device success (95.3% vs. 95.1%, p=0.67), 30-day mortality (1.9% vs. 4.9%, p=0.16), periprocedural stroke (1.4% vs. 4.9%, p=0.27), and major access site complications (9.4% vs. 9.8%, p=0.93). PPI was more frequent (19.4% vs. 34.4%, p=0.01) and significant PVL was less frequent (≥mild PVL: 17.6% vs. 3.7%, p=0.04) after Lotus implantation. No association was found between landing zone calcification and periprocedural stroke rate (OR 1.19, 95%CI 0.92-1.54, p=0.17) or need for PPI (OR 1.04, 95%CI 0.91-1.18, p=0.57). The extent of landing zone calcification was associated with risk for PVL ≥mild (OR 1.21, 95%CI 1.03-1.42, p=0.02). After adjusting for landing zone calcification risk for PVL ≥mild was lower with the Lotus valve (OR 0.15, 95%CI 0.02-0.54, p=0.01).

CONCLUSION

Both THVs yield comparable procedural and clinical outcomes except for a higher PPI rate with the Lotus valve, which is independent from the extent of landing zone calcification. The extent of landing zone calcification is associated with an increased risk for PVL for both THV, but is significantly reduced with the Lotus valve.

Variations in rotation of the aortic root and membranous septum with implications for transcatheter valve implantation

Objective

It is intuitive to suggest that knowledge of the variation in the anatomy of the aortic root may influence the outcomes of transcatheter implantation of the aortic valve (TAVI). We have now assessed such variation.

Methods

We used 26 specimens of normal hearts and 78 CT data sets of adults with a mean age of 64±15 years to measure the dimensions of the membranous septum and to assess any influence played by rotation of the aortic root, inferring the relationship to the atrioventricular conduction axis.

Results

The aortic root was positioned centrally in the majority of both cohorts, although with significant variability. For the cadaveric hearts, 14 roots were central (54%), 4 clockwise-rotated (15%) and 8 counterclockwise-rotated (31%). In the adult CT cohort, 44 were central (56%), 21 clockwise-rotated (27%) and 13 counterclockwise-rotated (17%). A mean angle of 15.5° was measured relative to the right fibrous trigone in the adult CT cohort, with a range of −32° to 44.7°. The dimensions of the membranous septum were independent of rotation. Fibrous continuity between the membranous septum and the right fibrous trigone increased with counterclockwise to clockwise rotation, implying variation in the relationship to the atrioventricular conduction axis.

Conclusions

The central fibrous body is wider, providing greater fibrous support, in the setting of clockwise rotation of the aortic root. Individuals with this pattern may be more vulnerable to conduction damage following TAVI. Knowledge of such variation may prove invaluable for risk stratification.

Predictors of permanent pacemaker implantation after transfemoral aortic valve implantation with the Lotus valve

BACKGROUND

Permanent pacemaker implantation (PPMI) after transcatheter aortic valve implantation is of high clinical relevance, but PPMI rates differ widely between valve types. Although the Lotus valve can be repositioned, reported rates for PPMI are high. The predictors of PPMI after Lotus valve implantation have not been defined yet.

METHODS

We analyzed the impact of preexisting conduction disturbances, depth of implantation, oversizing, and amount of calcification on PPMI in 216 patients with severe symptomatic aortic stenosis underdoing Lotus valve implantation.

RESULTS

PPMI was required in 39.8% of patients. Patients with need for PPMI compared with patients without need for PPMI had more often the following criteria: male gender (P=.035); preprocedural right bundle-branch block (RBBB) (16.3% vs 0, P<.001); atrioventricular (AV) block first degree (26.7% vs 10.1%, P=.004); higher calcium volume of the left coronary cusp (63.1±87.5 mm³ vs 42.8±49.3 mm³, P=.05); and deeper valve implantation at right coronary (P=.011), noncoronary (P=.026), and left coronary (P=.012) position. Oversizing in relation to annulus and left ventricular outflow tract did not have an impact on need for PPMI. By multiple regression analysis, preprocedural AV block first degree (P=.005), RBBB (P<.001), and depth of implantation (P=.006) were independent risk factors for need of PPMI.

CONCLUSIONS

In patients with severe aortic stenosis receiving transfemoral Lotus valve, preexisting AV block first degree, RBBB, and implantation depth are independent predictors of PPMI, highlighting the importance of careful valve positioning.

Conduction Disturbances After Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR) has become a well-accepted option for treating patients with aortic stenosis at intermediate to high or prohibitive surgical risk. TAVR-related conduction disturbances, mainly new-onset left bundle-branch block and advanced atrioventricular block requiring permanent pacemaker implantation, remain the most common complication of this procedure. Furthermore, improvements in TAVR technology, akin to the increasing experience of operators/centers, have translated to a major reduction in periprocedural complications, yet the incidence of conduction disturbances has remained relatively high, with perhaps an increasing trend over time. Several factors have been associated with a heightened risk of conduction disturbances and permanent pacemaker implantation after TAVR, with prior right bundle-branch block and transcatheter valve type and implantation depth being the most commonly reported. New-onset left bundle-branch block and the need for permanent pacemaker implantation may have a significant detrimental association with patients’ prognosis. Consequently, strategies intended to reduce the risk and to improve the management of such complications are of paramount importance, particularly in an era when TAVR expansion toward treating lower-risk patients is considered inevitable. In this article, we review the available evidence on the incidence, predictive factors, and clinical association of conduction disturbances after TAVR and propose a strategy for the management of these complications.

Impact of QRS Duration on Decision of Early Removal of Pacing Catheter After Transcatheter Aortic Valve Replacement With CoreValve Device

The purpose of this study was to determine the predictability of QRS duration (QRSd) for temporary pacing catheter removal in patients implanted with CoreValve. Permanent pacemaker implantation is a known complication after transcatheter aortic valve replacement (TAVI) with CoreValve. Although post-TAVI QRSd is highly predictive for advanced atrioventricular block (AVB), management of delayed AVB after TAVI remains unclear. We conducted a multicentric, prospective study of 156 consecutive patients who underwent TAVI with CoreValve between December 2010 and January 2013. Patients who had acute AVB after TAVI were excluded (n = 25). We classified the patients into 2 groups based on the post-TAVI QRSd. Patients with QRSd <120 ms were assigned to early pacing catheter removal group (n = 34), and patients with QRSd ≥120 ms were assigned to keep the pacing catheter with monitoring group (n = 97). No patient required permanent pacemaker implantation in the early pacing catheter removal group, whereas 38 patients with QRSd ≥120 ms had a delayed AVB (QRSd <120 ms vs ≥120 ms: 0% vs 39%, p = 0.0001). The intensive care unit stay length, 30-day mortality, and incidence of complications were lower in the early catheter removal group. Post-TAVI QRSd allows patient selection for early removal of pacing catheter in patients implanted with CoreValve.