Treatment and Clinical Outcomes of Transcatheter Heart Valve Thrombosis

Recurrent hypo-attenuated leaflet thickening after TAVR: Clinical implications

Subclinical bioprosthetic valve thrombosis (BPVT) is a relatively common finding in asymptomatic patients during follow-up imaging. However, its clinical significance is unclear. Data from registries associate BPVT with elevated valve gradients, thromboembolic complications, recurrence, and valve degeneration. Given the dynamic nature of the disease process, management is challenging. The duration of anticoagulation is unpredictable, and the need for frequent monitoring of BPVT, even in subclinical scenarios, is unclear. Our report is shedding the light on the clinical implications BPVT.

Long-Term Risk of Stroke After Transcatheter Aortic Valve Replacement: Insights From the SwissTAVI Registry

BACKGROUND

Stroke after transcatheter aortic valve replacement (TAVR) is associated with considerable morbidity and mortality. Predictors of stroke and the long-term risk after TAVR remain incompletely understood.

OBJECTIVES

The authors sought to investigate the short- and long-term incidence and predictors of stroke after TAVR in the SwissTAVI Registry.

METHODS

Between February 2011 and June 2021, consecutive patients undergoing TAVR were included. Standardized stroke ratios (SSRs) were calculated to compare trends in stroke of TAVR patients with an age- and sex-matched general population in Switzerland derived from the 2019 Global Burden of Disease study.

RESULTS

A total of 11,957 patients (81.8 ± 6.5 years of age, 48.0% female) were included. One-third of the patients (32.3%) had a history of atrial fibrillation, and 11.8% had a history of cerebrovascular accident. The cumulative 30-day incidence rate of stroke was 3.0%, with 69% of stroke events occurring within the first 48 hours after TAVR. The incidence of stroke was 4.3% at 1 year, and 7.8% at 5 years. Compared with an age- and sex-adjusted general population, the risk of stroke was significantly higher in the TAVR population during the first 2 years after TAVR: first year: SSR 7.26 (95% CI: 6.3-8.36) and 6.82 (95% CI: 5.97-7.79) for males and females, respectively; second year: SSR 1.98 (95% CI: 1.47-2.67) and 1.48 (95% CI: 1.09-2.02) for males and females, respectively; but returned to a comparable level to that observed in the matched population thereafter.

CONCLUSIONS

Compared with an age- and sex-matched population, TAVR patients experienced a higher risk of stroke for up to 2 years after the procedure, and a comparable risk thereafter. (SwissTAVI Registry; NCT01368250).

Investigation of factors determining haemodynamic relevance of leaflet thrombosis after transcatheter aortic valve implantation

AIMS

To determine the conditions under which early hypoattenuated leaflet thickening (HALT) after transcatheter aortic valve implantation (TAVI) becomes haemodynamically relevant.

METHODS AND RESULTS

The study included 100 patients (age: 81.5 ± 5.5 years; female 63%), thereof 50 patients with HALT. After anonymization and randomization, blinded readers measured maximum thrombus thickness per prosthesis (MT_pr) and movement restriction (MR_pr) on electrocardiogram (ECG)-gated whole heart cycle computed tomography angiography. These measurements were compared with echocardiographic mean pressure gradient (mPG), its increase from baseline (ΔmPG), and Doppler velocity index (DVI). Haemodynamic valve deterioration (HVD) was defined as mPG > 20 mmHg. Age, body mass index, valve type, valve size, left ventricular ejection fraction, and atrial fibrillation were considered as influencing factors. Multiple regression analysis revealed that only valve size (P = 0.001) and MT_pr (P = 0.02) had a significant influence on mPG. In an interaction model, valve size moderated the effect of MT_pr on mPG significantly (P = 0.004). Sub-group analysis stratified by valve sizes showed a strong correlation between MT_pr and echocardiographic parameters for 23 mm valves (mPG: r = 0.57, ΔmPG: r = 0.68, DVI: r = 0.55, each with P < 0.001), but neither for 26 nor 29 mm valves (r < 0.2, P > 0.2 for all correlations). Six of seven prostheses with HVD had a 23 mm valve diameter, while one had 29 mm (P = 0.02).

CONCLUSION

Early HALT rarely causes significant mPG increase. Our study shows that valve size is a key factor influencing the haemodynamic impact of HALT. In small valve sizes, mPG is more likely to increase. Our study is the first to offer in vivo evidence supporting previous in vitro findings on this topic.

Clinical valve thrombosis and arterial embolism in a cancer patient after transcatheter aortic valve replacement

The number of cancer patients with severe aortic stenosis and atrial fibrillation (AF) is increasing in the aging population. Transcatheter aortic valve replacement (TAVR) is an established treatment option for severe aortic stenosis with high surgical risk, including individuals with cancer. Antithrombotic therapy should be considered for post-TAVR or AF patients. However, antithrombotic management in cancer patients remains challenging due to the increased risk of both thromboembolism and bleeding. We present a case of clinical valve thrombosis and arterial embolism after transcatheter aortic valve replacement in an elderly patient with a history of metastatic pancreatic cancer and permanent atrial fibrillation under treatment of single antiplatelet therapy. Warfarin treatment after successful surgical thrombectomy to the occluded arteries improved clinical valve thrombosis, although the long-term outcome remains unclear. This case demonstrates that novel management algorithms for thromboembolism and bleeding in elderly cancer patients with AF and valvular heart disease are urgently needed.

Antithrombotic therapy following transcatheter aortic valve intervention

Transcatheter aortic valve replacement (TAVR) is increasingly being performed to treat symptomatic patients with aortic stenosis and annual procedure volume has overtaken surgical aortic valve replacement in the United States. However, current international guidelines were written prior to the publication of several important recent studies. Furthermore, European and American guidelines differ in their recommendations of antithrombotic therapy following TAVR. Consequently, there is a need to examine the literature to provide clinicians guidance on the optimum antithrombotic strategy, particularly as different patient populations exist. In this review, we examine the data for antiplatelet and anticoagulation therapy post-TAVR.

Hyperacute Sapien Aortic Valve thrombosis in a patient with Antiphospholipid Syndrome (APS)

In this case we briefly describe the case of an old woman presenting with acute exertional dyspnea due to hyperacute Sapien Valve thrombosis.

Imaging of Bioprosthetic Valve Dysfunction after Transcatheter Aortic Valve Implantation

Transcatheter aortic valve implantation (TAVI) has become the standard of care in elderly high-risk patients with symptomatic severe aortic stenosis. Recently, TAVI has been increasingly performed in younger-, intermediate- and lower-risk populations, which underlines the need to investigate the long-term durability of bioprosthetic aortic valves. However, diagnosing bioprosthetic valve dysfunction after TAVI is challenging and only limited evidence-based criteria exist to guide therapy. Bioprosthetic valve dysfunction encompasses structural valve deterioration (SVD) resulting from degenerative changes in the valve structure and function, non-SVD resulting from intrinsic paravalvular regurgitation or patient-prosthesis mismatch, valve thrombosis, and infective endocarditis. Overlapping phenotypes, confluent pathologies, and their shared end-stage bioprosthetic valve failure complicate the differentiation of these entities. In this review, we focus on the contemporary and future roles, advantages, and limitations of imaging modalities such as echocardiography, cardiac computed tomography angiography, cardiac magnetic resonance imaging, and positron emission tomography to monitor the integrity of transcatheter heart valves.

Echocardiographic Evaluation after Transcatheter Aortic Valve Implantation: A Comprehensive Review

Transcatheter aortic valve implantation (TAVI) is an increasingly popular treatment option for patients with severe aortic stenosis. Recent advancements in technology and imaging tools have significantly contributed to the success of TAVI procedures. Echocardiography plays a pivotal role in the evaluation of TAVI patients, both before and after the procedure. This review aims to provide an overview of the most recent technical advancements in echocardiography and their use in the follow-up of TAVI patients. In particular, the focus will be on the examination of the influence of TAVI on left and right ventricular function, which is frequently accompanied by other structural and functional alterations. Echocardiography has proven to be key also in detecting valve deterioration during extended follow-up. This review will provide valuable insights into the technical advancements in echocardiography and their role in the follow-up of TAVI patients.

Subclinical Leaflet Thrombosis After Balloon versus Self-Expandable Transcatheter Aortic Valve Implantation

Hypoattenuated leaflet thickening (HALT) has been recognized as one of the complications after transcatheter aortic valve implantation and may promote structural valve degeneration and increase the risk of cerebrovascular events. The 2 main types of available transcatheter heart valves (THVs), the balloon-expandable (BE) and the self-expanding (SE), are interchangeably used in clinical practice despite substantial design differences. There is unclear evidence on whether these 2 different THV models are achieving similar or different rates of subclinical leaflet thrombosis/HALT. A systematic search of electronic databases was conducted to identify studies that reported the incidence of HALT between SE THVs and BE THVs. The Mantel-Haenszel method was used to calculate the 95% confidence interval and pooled risk ratio with a random-effects model. A total of 126 records were identified, of which 22 studies comprising 14,401 patients were included in our final analysis. Among 5,951 patients receiving SE THVs, 194 (3.2%) developed HALT, compared with 8,450 patients receiving BE THVs, of whom 484 (5.7%) developed HALT. There was a statistically significant decrease in the risk of developing HALT in patients receiving SE THVs compared with those receiving BE THVs (risk ratio 0.75, 95% confidence interval 0.59 to 0.95, I² 32%, p = 0.02). In conclusion, could potentially reduce the risk of HALT/subclinical leaflet thrombosis.

Optimal Anticoagulation on TAVI Patients Based on Thrombotic and Bleeding Risk and the Challenge Beyond: A Systematic Review and Meta-Analysis

Transcatheter Aortic Valve Replacement (TAVR) has been established as the treatment of choice for symptomatic aortic stenosis, while it is expanding in all risk-related group categories of patients, gaining gradually ground over the surgical approach. However, complications and adverse events are yet to be effectively limited and diminished with thrombotic and hemorrhagic events being rooted as a crucial topic of discussion. Favorable anticoagulation pharmacotherapy options are constantly being revised and tested, whilst guidelines are being modified to meet current clinical evidence. This review aims to systematically assess already existing guidelines on anticoagulation in post-TAVI patients and examine novel regimens for the specific use, like apixaban, rivaroxaban, and other anticoagulants, essentially constructing a holistic point of view on future progress on this matter. The added complexity brought by coagulation-affecting comorbidities such as atrial fibrillation, coronary artery disease, and more contributes to the direct association of the topic to the quality of healthcare as a public service. The literature was systematically searched to examine the effectiveness and safety of various anticoagulation treatments and cross-evaluate them based on the according category of patients that were assigned to. Clinical trials, observational studies and systematic reviews were included and, eventually, conclusive remarks and future considerations were developed and presented. In the category of patients without prior indication to anticoagulation, SAPT was proven safer and still effective, when antiplatelet therapies were compared, while a comparison of antiplatelet versus anticoagulation strategies noted the first one, with limited data, as the optimal one. Lastly, direct oral anticoagulants were shown to be safe substitutes for vitamin K antagonists for patients with prior indication to anticoagulation.

Natural History of Leaflet Thrombosis After Transcatheter Aortic Valve Replacement: A 5-Year Follow-Up Study

Background Subclinical leaflet thrombosis, characterized by hypoattenuated leaflet thickening (HALT) on multidetector computed tomography, is common after transcatheter aortic valve replacement (TAVR). Because little is known about the long-term natural history of subclinical HALT, we aimed to investigate this in patients who underwent TAVR without using additional anticoagulation. Methods and Results We retrospectively evaluated patients who underwent TAVR with the Edwards SAPIEN-XT at our institute between October 2013 and December 2015. Patients were grouped according to the presence or absence of HALT within 1 year after TAVR (HALT and No-HALT groups). The primary outcome, defined as the composite of all-cause mortality, heart failure readmission, and ischemic stroke, was compared. Valve performance was assessed over time by transthoracic echocardiography. Among 124 patients (men: 29.1%; median age, 85 years), 27 (21.8%) showed HALT on multidetector computed tomography within 1 year after TAVR. No patient required additional anticoagulation for treating HALT because of the absence of valve-related symptomatic deterioration. During the median follow-up period of 4.7 years (interquartile range, 4.0-5.6), the rate of primary outcome and valve performance was not statistically different between the 2 groups (37.0% versus 38.1%; log-rank test P=0.92; mean pressure gradient, 9 mm Hg [8-14 mm Hg] versus 10 mm Hg [7-15 mm Hg]; P=0.51, respectively). Conclusions Approximately 20% of patients after TAVR had HALT within 1 year; however, that did not change the risk of subsequent adverse cardiovascular events or the valve performance with statistical significance for up to 5 years despite no additional anticoagulation therapy.

Thrombolysis for Cardiogenic Shock Secondary to Aortic Bioprosthetic Valve-in-Valve Thrombosis

Valvular obstruction and thromboembolism are feared complications of bioprosthetic valve thrombosis. We describe the case of an 81-year-old man with a prior aortic valve-in-valve bioprosthesis who presented in cardiogenic shock, requiring mechanical circulatory support. He was found to have acute bioprosthetic valve thrombosis and was treated with systemic thrombolysis. This case highlights the overall uncertainty regarding the optimal treatment of acute bioprosthetic valve thrombosis. Society guidelines and the current evidence behind prophylaxis and treatment are reviewed. Although the data remain sparse, systemic thrombolysis may be an effective strategy in critically ill patients who are poor surgical candidates.

The search for optimal antithrombotic therapy in transcatheter aortic valve implantation: facts and uncertainties

Transcatheter aortic valve implantation (TAVI) is a minimally invasive procedure, which is used frequently in patients with symptomatic severe aortic valve stenosis. Most patients undergoing TAVI are over 80 years of age with a high bleeding as well as thrombotic risk. Despite the increasing safety of the procedure, thromboembolic events [stroke, (subclinical) valve thrombosis] remain prevalent. As a consequence, antithrombotic prophylaxis is routinely used and only recently new data on the efficacy and safety of antithrombotic drugs has become available. On the other hand, these antithrombotic drugs increase bleeding in a population with unique aortic stenosis-related bleeding characteristics (such as acquired von Willebrand factor defect and angiodysplasia). In this review, we discuss the impact of thromboembolic and bleeding events, the current optimal antithrombotic therapy based on registries and recent randomized controlled trials, as well as try to give a practical guide how to treat these high-risk patients. Finally, we discuss knowledge gaps and future research needed to fill these gaps.

Incidence and mechanisms of bioprosthetic dysfunction after transcatheter implantation of a mechanically-expandable heart valve

BACKGROUND

The mechanically-expandable transcatheter valve is no longer commercially available, yet clinical and echocardiographic surveillance is imperative for thousands of patients who received transcatheter aortic valve implantation (TAVI) with this platform.

AIMS

We aimed to determine the incidence and mechanism of bioprosthetic valve dysfunction (BVD) following TAVI with mechanically-expandable valves.

METHODS

From 2013 to 2020, all 234 patients who underwent TAVI with the LOTUS valve were included. BVD was categorised as (i) structural valve deterioration (SVD), (ii) non-structural valve dysfunction (NSVD), (iii) clinical valve thrombosis and (iv) endocarditis, according to the Valve Academic Research Consortium-3 criteria.

RESULTS

The mean age was 79±7 years, 60% were male, and the mean Society of Thoracic Surgeons score was 4.2±2.9%. The technical success rate was 94% and the 30-day device success rate was 78%. All-cause mortality at 1 year was 15%; median follow-up duration was 36 (IQR 18-60) months during which 47% of patients died. One hundred and three patients had ≥1 type of BVD (44%), which predominantly consisted of NSVD (39%, mostly because of ≥moderate patient-prosthesis mismatch). BVD during follow-up included endocarditis (3.4%), clinical valve thrombosis (3.4%) and SVD (1.3%). Both endocarditis and clinically apparent valve thrombosis occurred early and late after TAVI and resulted in valve-related deaths in 38% and 13% of patients, respectively. Overall, ≥moderate haemodynamic valve deterioration occurred in 5.5% and bioprosthetic failure in 7.3%, leading to valve-related deaths in 36% of cases.

CONCLUSIONS

BVD represents a relevant health issue after TAVI with a mechanically-expandable valve. Serious but reversible causes of BVD include endocarditis and clinically apparent valve thrombosis, both carrying a time-independent hazard post-TAVI.

Structural analysis of regional transcatheter aortic valve underexpansion and its implications for subclinical leaflet thrombosis

Subclinical leaflet thrombosis has been increasingly recognized following transcatheter aortic valve replacement (TAVR). Determining the risk factors is vital in preventing clinical leaflet thrombosis and ensuring long-term value durability. Clinical data have indicated that regional stent under-expansion of transcatheter aortic valves (TAVs), particularly self-expanding devices, may be associated with an increased risk of subclinical leaflet thrombosis. This study aimed to determine the effects of regional TAV frame under-expansion on leaflet kinematics, leaflet structural characteristics, and explore its impact on the likelihood of leaflet thrombosis. In this study, mild and moderate regional frame under-expansion of a 26-mm CoreValve were examined using experimental testing and computational simulations. The results indicated that regional TAV frame under-expansion impairs leaflet kinematics and reduces the range of motion in leaflets with an angle less than 120°. The reduced range of motion can increase blood stasis on the surface of the TAV leaflets. The results also demonstrated that regional frame under-expansion induced localized high-stress regions in the leaflets close to the fixed boundary edge. The increased mechanical stress can lead to accelerated tissue degeneration. The study improves our understanding of the effects of regional stent under-expansion in TAVR. Post-procedural balloon dilatation of self-expanding TAVs can potentially be advantageous in reducing leaflet distortion and normalizing leaflet stress distribution. Large-scale, prospective, and well-controlled studies are needed to further investigate regional TAV frame under-expansion effects on subclinical leaflet thrombosis and long-term valve durability.

Antithrombotic strategies after transcatheter aortic valve implantation: A systematic review and network meta-analysis of randomized controlled trials

AIMS

Meta-analyses comparing different antithrombotic strategies were conducted to determine the optimal therapeutic regimen post transcatheter aortic valve implantation (TAVI). However, there were restricted high-quality direct comparisons across the different antithrombotic therapeutic regimens. We sought to explore the safety and efficacy of different antithrombotic therapy strategies after TAVI using network meta-analyses of randomized controlled trials (RCTs).

METHODS

We searched CENTRAL, PubMed, Embase and Medline through August 2021 for RCTs that directly compared different antithrombotic schemes in adults who had undergone TAVI. We conducted a pairwise and network meta-analysis measuring all-cause mortality, stroke, myocardial infarction, all bleeding and life-threatening or major bleeding events. The surface under the cumulative ranking (SUCRA) curve was estimated to rank the therapies. We evaluated the risk of bias and graded the quality of the evidence using established methods.

RESULTS

Six RCTs of 2824 patients who underwent TAVI were analysed. The risk of all bleeding [relative risk (RR) 1.88 (1.34-2.64)] and life-threatening or major bleeding [RR 2.03 (1.27-3.24)] was significantly higher for dual antiplatelet therapy (DAPT) than single antiplatelet therapy (SAPT), whereas there was no significant difference in the risk of all-cause mortality [RR 1.01 (0.61-1.68)] between DAPT and SAPT. Oral anticoagulant (OAC) + SAPT (OACSAPT) had significantly higher rates of all bleeding and life-threatening or major bleeding events compared with SAPT ([RR 3.46 (2.23-5.36)], [RR 2.86 (1.50-5.45)]). The risk of all-cause mortality [RR 1.72 (1.14-2.59)] and all bleeding [RR 1.84 (1.38-2.44)] were significantly higher for OACSAPT than DAPT, whereas there was no significant difference in the risk of life-threatening or major bleeding events [RR 1.41 (0.89-2.23)] between DAPT and OACSAPT. There was no significant difference in stroke or myocardial infarction among the different antithrombotic strategies (SAPT, DAPT and OACSAPT). Additionally, patients receiving OACSAPT had the highest risks for all-cause mortality (SUCRA 3.5%) and life-threatening or major bleeding (SUCRA 2.3%). SAPT seemed to be superior to DAPT in terms of all-cause mortality (SUCRA SAPT: 76.7%, DAPT: 69.8%) and stroke (SUCRA 69.6%, 59.7%).

CONCLUSIONS

Except for OACSAPT having a higher all-cause mortality than DAPT, patients who underwent TAVI had similar all-cause mortality, stroke and myocardial infarction rates among different antithrombotic regimens. Patients on SAPT had a significantly lower bleeding risk than those on DAPT and OACSAPT. Our study indicates that SAPT is the preferred therapeutic strategy when there is no indication for OAC or DAPT. Furthermore, the application of OACSAPT was ranked the worst among all antithrombotic regimens and should be averted due to an increased risk of all-cause mortality and all bleeding.

Bioprosthetic Aortic Valve Thrombosis and Literature Review

An 83-year-old gentleman with a history of 23-mm Hancock-II-bioprosthetic aortic valve (BAV) replacement ten-years prior presented with symptoms of dyspnea and lower extremity edema. During the preceding seven-years, he had been noted to have asymptomatic increased mean transvalvular gradients (MG; 36–50 mmHg) felt to be due to either early bioprosthetic degeneration, pannus formation, or patient–prosthesis mismatch. An echocardiogram at the time of symptom development demonstrated significant flow acceleration through the aortic valve, mild regurgitation, and severely increased MG (48 mmHg) with prolonged acceleration time (AT, 140 msec). A trial of warfarin anticoagulation resulted in dramatic improvement after only 6 weeks with laminar flow through the AV, near-total resolution of regurgitation, and a decrease in MG to 14 mmHg and AT to 114 msec. These findings strongly suggest that BAV thrombosis was the predominant mechanism responsible for the longstanding high MG. Our case highlights that BAV thrombosis should be considered in the differential of elevated gradients regardless of the age of prosthesis, and that a trial of warfarin anticoagulation may be beneficial even if elevated gradients have been present for a prolonged period. Valvular gradients are often abnormal long before a formal diagnosis; however, these may reverse quickly with anticoagulation therapy.

Biomechanics of Transcatheter Aortic Valve Implant

Transcatheter aortic valve implantation (TAVI) has grown exponentially within the cardiology and cardiac surgical spheres. It has now become a routine approach for treating aortic stenosis. Several concerns have been raised about TAVI in comparison to conventional surgical aortic valve replacement (SAVR). The primary concerns regard the longevity of the valves. Several factors have been identified which may predict poor outcomes following TAVI. To this end, the lesser-used finite element analysis (FEA) was used to quantify the properties of calcifications which affect TAVI valves. This method can also be used in conjunction with other integrated software to ascertain the functionality of these valves. Other imaging modalities such as multi-detector row computed tomography (MDCT) are now widely available, which can accurately size aortic valve annuli. This may help reduce the incidence of paravalvular leaks and regurgitation which may necessitate further intervention. Structural valve degeneration (SVD) remains a key factor, with varying results from current studies. The true incidence of SVD in TAVI compared to SAVR remains unclear due to the lack of long-term data. It is now widely accepted that both are part of the armamentarium and are not mutually exclusive. Decision making in terms of appropriate interventions should be undertaken via shared decision making involving heart teams.

Evolving concepts in the management of antithrombotic therapy in patients undergoing transcatheter aortic valve implantation

Thromboembolic and bleeding complications negatively impact recovery and survival after transcatheter aortic valve implantation (TAVI). Particularly, there is a considerable risk of ischaemic stroke and vascular access related bleeding, as well as spontaneous gastro-intestinal bleeding. Therefore, benefit and harm of antithrombotic therapy should be carefully balanced. This review summarizes current evidence on peri- and post-procedural antithrombotic treatment. Indeed, in recent years, the management of antithrombotic therapy after TAVI has evolved from intensive, expert opinion-based strategies, towards a deescalated, evidence-based approach. Besides per procedural administration of unfractionated heparin, this encompasses single antiplatelet therapy in patients without a concomitant indication for oral anticoagulation (OAC); and OAC monotherapy in patients with such indication, mainly being atrial fibrillation. Combination therapy should generally be avoided to reduce bleeding risk, except after recent coronary stenting where a period of dual antiplatelet therapy (aspirin plus P2Y12-inhibitor) or P2Y12-inhibitor plus OAC (in patients with an independent indication for OAC) is recommended to prevent stent thrombosis. This new paradigm in which reduced antithrombotic intensity leads to improved patient safety, without a loss of efficacy, may be particularly suitable for elderly and fragile patients. Whether this holds in upcoming populations of younger and lower-risk patients and in specific populations as patients with subclinical valve thrombosis, is yet to be proven. Finally, whether less intensive or alternative approaches should be also applied for the periprocedural management of the antithrombotic therapy, has to be determined by ongoing and future studies.

Chronic thrombosis of bioprostheses: Diagnosis and management

Acquired valvular heart disease is associated with increased mortality and morbidity. While the etiology of the valvular dysfunction determines the mode of treatment, over 100,000 valve operations are performed annually in the US with the use of bioprosthetic valves comprising up to 90%. While bioprosthetic valves do not require life long anticoagulation, the incidence of prosthetic valve thrombosis is continuously increasing. This article reviews the current status on diagnosis, treatment modalities and management of bioprosthetic valve thrombosis.

Biomechanics of Transcatheter Aortic Valve Replacement Complications and Computational Predictive Modeling

Transcatheter aortic valve replacement (TAVR) is a rapidly growing field enabling replacement of diseased aortic valves without the need for open heart surgery. However, due to the nature of the procedure and nonremoval of the diseased tissue, there are rates of complications ranging from tissue rupture and coronary obstruction to paravalvular leak, valve thrombosis, and permanent pacemaker implantation. In recent years, computational modeling has shown a great deal of promise in its capabilities to understand the biomechanical implications of TAVR as well as help preoperatively predict risks inherent to device-patient-specific anatomy biomechanical interaction. This includes intricate replication of stent and leaflet designs and tested and validated simulated deployments with structural and fluid mechanical simulations. This review outlines current biomechanical understanding of device-related complications from TAVR and related predictive strategies using computational modeling. An outlook on future modeling strategies highlighting reduced order modeling which could significantly reduce the high time and cost that are required for computational prediction of TAVR outcomes is presented in this review paper. A summary of current commercial/in-development software is presented in the final section.

A case of early thrombosis following a percutaneous tricuspid valve in valve implantation managed by thrombolysis

Bioprosthetic valve thrombosis (BPVT) is a growing recognized entity, especially with the increasing use of the valve in vale procedures and the advent of new detection technologies (e.g., 4D CT and 4D echocardiography). The incidence of BPVT is higher in transcatheter valves than surgically implanted bioprosthetic valves. However, the best thromboprophylaxis regimen and optimal management strategy in the acute context remain unknown. This paper presents a case of early thrombosis following the percutaneous tricuspid valve in vale procedure that was successfully managed with thrombolysis.

Antithrombotic Therapy Following Transcatheter Aortic Valve Replacement

Due to a large technical improvement in the past decade, transcatheter aortic valve replacement (TAVR) has expanded to lower-surgical-risk patients with symptomatic and severe aortic stenosis. While mortality rates related to TAVR are decreasing, the prognosis of patients is still impacted by ischemic and bleeding complications, and defining the optimal antithrombotic regimen remains a priority. Recent randomized control trials reported lower bleeding rates with an equivalent risk in ischemic outcomes with single antiplatelet therapy (SAPT) when compared to dual antiplatelet therapy (DAPT) in patients without an underlying indication for anticoagulation. In patients requiring lifelong oral anticoagulation (OAC), the association of OAC plus antiplatelet therapy leads to a higher risk of bleeding events with no advantages on mortality or ischemic outcomes. Considering these data, guidelines have recently been updated and now recommend SAPT and OAC alone for TAVR patients without and with a long-term indication for anticoagulation. Whether a direct oral anticoagulant or vitamin K antagonist provides better outcomes in patients in need of anticoagulation remains uncertain, as recent trials showed a similar impact on ischemic and bleeding outcomes with apixaban but higher gastrointestinal bleeding with edoxaban. This review aims to summarize the most recently published data in the field, as well as describe unresolved issues.

Bioprosthetic valve failure. Comparative trial of two balloon-expandable transcatheter heart valve systems in intermediate-risk patients: a propensity score analysis

BACKGROUND

The comparative mid and long-term durability, including the rates of bioprosthetic valve failure (BVF) of the Sapien XT^® and Sapien 3^® transcatheter heart valve (THV) in patients with intermediate surgical risk has not been reported.

METHODS

Consecutive intermediate-risk patients with severe aortic stenosis from the Mexican registry of transcatheter aortic valve replacement (TAVR) with Sapien^® THVs were included. The primary endpoint was to compare the BVF rate between THVs at 2 years of follow-up. Secondary endpoints were comparisons of the composite of global mortality, cardiovascular mortality, and neurological events at 30 d and 24 months of follow-up.

RESULTS

During 2014-2019, 115 (60 Sapien XT^® and 55 Sapien 3^®) patients met the inclusion criteria in five medical centres. The mean age was 77.3 ± 8.4 years. The average Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) was 5.6 ± 2.9. There was no statistically significant difference between the groups in BVF rate. At 30 d, overall, cardiovascular and non-cardiovascular mortality was 4.3%, 2.6%, and 1.7%, respectively. Neurological events rate was 1.73%. The mean long-term follow-up was 25.3 ± 14.2 months with an overall mortality of 9.56% but lower for the Sapien 3^® group (15% vs. 3.6%, p=.037). The only independent predictor of composite mortality and neurological events that occurred in the long term was using a Sapien XT^® [OR 1.6, CI 95%, 1.0-24.9; p=.049].

CONCLUSIONS

The BVF rate at 25 months of follow-up was similar with the XT and S3 systems. During this follow-up period, the major composite events of death from any cause and neurological events were significantly lower with the S3 system.

Society for Maternal-Fetal Medicine Consult Series #61: Anticoagulation in pregnant patients with cardiac disease

Pregnancy in individuals with a mechanical heart valve has been classified as very high risk because of a substantially increased risk of maternal mortality or severe morbidity. Lifelong therapeutic anticoagulation is a principal component of the medical management of mechanical heart valves to prevent valve thrombosis. Anticoagulation regimens indicated outside of pregnancy for patients with mechanical valves should be continued during pregnancy with the possibility of modifications based on the type of valve, the trimester of pregnancy, individual risk tolerance, and circumstances around the time of delivery. The purpose of this document is to provide recommendations regarding the management of anticoagulation for common cardiac conditions complicating pregnancy, including mechanical heart valves, atrial fibrillation, systolic heart failure, and congenital heart disease.

Subclinical Leaflet Thrombosis After Transcatheter Aortic Valve Replacement: A Meta-Analysis

This meta-analysis and systematic review was performed to evaluate the clinical relevance of subclinical leaflet thrombosis (SLT) following transcatheter aortic valve replacement. PubMed, Web of Science, and CENTRAL were searched for eligible randomized and nonrandomized studies until November 2020. Risk ratios (RRs) or odds ratios and 95% CIs were calculated, using a random-effects model. Overall, 25 studies were eligible for the analysis and comprised a total of 11,098 patients. The median incidence of SLT was 6% at a median follow-up of 30 days. Use of intra-annular valves was associated with 2-fold greater risk for the development of SLT compared with use of supra-annular valves. There was no difference in the risk for SLT (RR: 0.97; 95% CI: 0.72-1.29; P = 0.83) between single-antiplatelet therapy (SAPT) and dual-antiplatelet therapy (DAPT), whereas oral anticoagulation (OAC) was associated with a 58% relative risk reduction for SLT (RR: 0.42; 95% CI: 0.29-0.61; P < 0.00001) compared with SAPT and DAPT. In patients with diagnosed leaflet thrombosis at follow-up, the risk for stroke or transient ischemic attack was increased by 2.6-fold (RR: 2.56; 95% CI: 1.60-4.09; P < 0.00001) compared with patients without leaflet thrombosis. In patients diagnosed with SLT, the odds of SLT resolution increased by 99% after switch from antiplatelet agents to OAC (odds ratio: 0.01; 95% CI: 0.00-0.06; P < 0.00001). To summarize, indication-based use of OAC after transcatheter aortic valve replacement is associated with a lower risk for SLT compared with SAPT and DAPT. Switching to OAC seems to be effective for SLT resolution. As SLT increased the odds of stroke or transient ischemic attack in the included population, further studies are needed to investigate whether screening tests for SLT and appropriate antithrombotic therapy improve long-term valve functionality and clinical prognosis.

Case Report: Leaflet Thrombosis After Transcatheter Aortic Valve Replacement With Worsening Heart Failure—A Successful Resolution Using Non-vitamin K Antagonist Oral Anti-coagulant

Background: Transcatheter aortic valve replacement (TAVR) is indicated for treating symptomatic severe aortic valve stenosis (AS) with intermediate-to-high surgical risks. Few reports are available on managing leaflet thrombosis after TAVR with worsening heart failure.

Case Summary: A 77-year-old man with severe AS and coronary artery disease (CAD) received a successful TAVR with Edwards Sapien 3 valve. A year later, the patient developed a worsening heart failure with pulmonary edema, new-onset atrial fibrillation (Af), an increase in mean trans-aortic valve pressure gradient to 48 mmHg, worsening mitral regurgitation (MR), and pulmonary hypertension (PH). The response of the patient to intravenous diuretics and inotropic treatments was poor. Multi-slice CT (MDCT) revealed hypo-attenuated thrombus and thickened transcatheter heart valve leaflets. A non-vitamin K antagonist oral anti-coagulant (NOAC) was added to treat the new-onset Af and leaflet thrombosis on top of the con-current single antiplatelet for CAD. A series of follow-up echocardiograms showed a progressive decrease in trans-aortic valve pressure gradient to 17 mmHg and reductions in MR and PH. Three months after the NOAC treatment, MDCT revealed the resolution of hypo-attenuated thrombus and thickened leaflets. Symptoms of heart failure were also improved gradually.

Discussion: Worsening heart failure or an increase in trans-aortic valve pressure gradient after TAVR warranted further MDCT studies. Leaflet thrombosis can be resolved after using NOAC as in our present case.

Transcatheter aortic valve thrombosis: a review of potential mechanisms

Transcatheter aortic valve (TAV) thrombosis has been recognized as a significant problem that sometimes occurs as early as within 30 days after valve implantation, leading to increased concerns of stroke and long-term valve durability. In this article, a critical summary of the relevant literature on identifying potential mechanisms of TAV thrombosis from the perspective of the well-known Virchow's triad, which comprises blood flow, foreign materials and blood biochemistry, is presented. Blood flow mechanisms have been the primary focus thus far, with a general consensus on the flow mechanisms with respect to haemodynamic conditions, the influence of TAV placement and expansion and the influence of coronary flow. Less attention has been paid to the influence of blood biochemistry and foreign materials (and related endothelial damage), with little consensus among studies with regards to platelet and/or microparticle levels post-TAV implantation. Finally, we discuss the future outlook for research with unanswered scientific questions.

Transcatheter Aortic Valve Leaflet Thrombosis: Prevalence, Management, and Future Directions

PURPOSE OF REVIEW

We review the pathology, prevalence, diagnosis, hemodynamics, risk factors, prognosis, and treatment of leaflet thrombosis (LT), and suggest future directions in this field.

RECENT FINDINGS

The latest meta-analysis showed the prevalence of overall LT is 5.4% (clinical LT of 1.2% and subclinical LT of 15.1%). Either subclinical or clinical LT is not associated with risk of mortality; however, clinical LT is associated with increased risk of stroke. Although LT can be reduced by oral anticoagulation therapy (OAT), routine use of OAT as primary prevention for high-risk patients is not recommended due to increased risk of mortality. Four-dimensional computed tomography plays an important role in the diagnosis of LT and the accumulation of qualitative or qualitative assessments of hypoattenuated leaflet thickening would provide more clues to clarify effective OAT strategies. In addition, further studies are warranted to evaluate the efficacy of other anticoagulants in low-intermediate risk patients.

Transcatheter Aortic Valve Implantation and Subclinical and Clinical Leaflet Thrombosis: Multimodality Imaging for Diagnosis and Risk Stratification

In recent years, the phenomenon of subclinical leaflet thrombosis (SLT) in patients who have undergone transcatheter aortic valve implantation has become increasingly relevant. Hypo-attenuating leaflet thickening and hypo-attenuation affecting motion diagnosed by CT are the hallmarks of SLT, and their incidence varies depending on the intensity of screening. Whether these phenomena are a surrogate for leaflet thrombosis reducing valve durability and increasing the risk of stroke is still a matter of debate. Uncertainty remains over the optimal antithrombotic therapy after TAVI and the best treatment strategy is still not confirmed. Ongoing and future trials will provide more evidence about the best strategy for the prevention and treatment of SLT.

Comparing Single- and Dual Antiplatelet Therapies Following Transcatheter Aortic Valve Implantation

BACKGROUND

Transcatheter aortic valve implantation has been an established treatment in patients with symptomatic severe aortic stenosis. However, the postoperative antiplatelet regimen after transcatheter aortic valve implantation was not established certainly. The aim of this meta-analysis is to compare the safety and efficacy of single- (SAPT) and dual-antiplatelet therapies (DAPT) in patients undergoing transcatheter aortic valve implantation.

METHODS

Eligible randomized controlled trials and cohort studies published before February 2021 were retrieved from PubMed, Embase, and the Cochrane Library. We calculated odds ratios with 95% confidence intervals.

RESULTS

Nine articles, involving 19,277 patients, met the selection criteria. In the short-term outcome, compared with SAPT, DAPT was associated with a significantly higher rate of bleeding (odds ratios, 95% confidence intervals: 3.00, 1.67-5.38) and showed no significant differences in thrombotic events (odds ratios, 95% confidence intervals: 1.25, 0.74-2.11) and all-cause mortality (odds ratios, 95% confidence intervals: 0.84; 0.42-1.69). In the long-term outcome, DAPT was associated with a significantly higher bleeding rate (odds ratios, 95% confidence intervals: 1.85, 1.24-2.78) and showed no differences in thrombotic events (odds ratios, 95% confidence intervals: 1.13, 0.86-1.48) and all-cause mortality (odds ratios, 95% confidence intervals: 1.12, 0.95-1.32). Our trial sequential analysis confirmed DAPT didn't confer any benefit for reducing all-cause mortality and thrombotic events, and carried a higher risk of bleeding than SAPT.

CONCLUSIONS

SAPT should be a sufficient antiplatelet strategy in post- transcatheter aortic valve implantation patients without indications for oral anticoagulation medication, especially in the long-term follow-up period.

Subclinical leaflet thrombosis after transcatheter aortic valve implantation: no association with left ventricular reverse remodeling at 1-year follow-up

Hypo-attenuated leaflet thickening (HALT) of transcatheter aortic valves is detected on multidetector computed tomography (MDCT) and reflects leaflet thrombosis. Whether HALT affects left ventricular (LV) reverse remodeling, a favorable effect of LV afterload reduction after transcatheter aortic valve implantation (TAVI) is unknown. The aim of this study was to examine the association of HALT after TAVI with LV reverse remodeling. In this multicenter case–control study, patients with HALT on MDCT were identified, and patients without HALT were propensity matched for valve type and size, LV ejection fraction (LVEF), sex, age and time of scan. LV dimensions and function were assessed by transthoracic echocardiography before and 12 months after TAVI. Clinical outcomes (stroke or transient ischemic attack, heart failure hospitalization, new-onset atrial fibrillation, all-cause mortality) were recorded. 106 patients (age 81 ± 7 years, 55% male) with MDCT performed 37 days [IQR 32–52] after TAVI were analyzed (53 patients with HALT and 53 matched controls). Before TAVI, all echocardiographic parameters were similar between the groups. At 12 months follow-up, patients with and without HALT showed a significant reduction in LV end-diastolic volume, LV end-systolic volume and LV mass index (from 125 ± 37 to 105 ± 46 g/m², p = 0.001 and from 127 ± 35 to 101 ± 27 g/m², p < 0.001, respectively, p for interaction = 0.48). Moreover, LVEF improved significantly in both groups. In addition, clinical outcomes were not statistically different. Improvement in LVEF and LV reverse remodeling at 12 months after TAVI were not limited by HALT.

Early Leaflet Thickening, Durability and Bioprosthetic Valve Failure in TAVR

All bioprosthetic valves, both surgical and transcatheter, have a finite lifespan before their leaflets inevitably degenerate, leading to stenosis or regurgitation. As younger, low-risk patients receive a transcatheter aortic valve, it is expected that they will most likely outlive their bioprosthetic valve. The heterogeneity of studies regarding surgical valve durability makes the interpretation of the data challenging. Leaflet thickening is seen in transcatheter heart valves but currently there is no evidence that it leads to premature valve deterioration or clinical events. Standardized definitions of structural valve deterioration should allow for comparisons between future clinical trials to assess the durability of different transcatheter heart valves.

Safety and efficacy of minimalist transcatheter aortic valve implantation using a new-generation balloon-expandable transcatheter heart valve in bicuspid and tricuspid aortic valves

BACKGROUND

Bicuspid aortic valve may be associated with increased complications during transcatheter aortic valve implantation (TAVI).

AIMS

Compare balloon-expandable transcatheter heart valve (THV) safety and efficacy in severe tricuspid (TAV) and bicuspid (BAV) aortic stenosis.

METHODS

Transfemoral TAVI was performed in 743 patients (Jan 2014-June 2019) using the SAPIEN 3 THV. Aortic valve morphology was determined using computed tomography. Valve Academic Research Consortium-2 (VARC-2) derived safety and efficacy endpoints at 1 year were evaluated.

RESULTS

BAV patients (n = 78), were younger (77 [72, 81] vs. 81 [78, 85] years, p < 0.001) with lower surgical risk (EuroSCORE II 2.96% vs. 4.51% p < 0.001). Bicuspid valves were more calcified (BAV 1308mm³, TAV 848mm³ p < 0.001) with more asymmetric calcification (BAV 63/78 (81%), TAV 239/665 (36%), p < 0.001). Device success (BAV 94%, TAV 90%, p = 0.45) and major vascular complications (BAV 6%, TAV 9%, p = 0.66) were comparable. At 1 year, there was a trend toward lower combined all-cause mortality and rehospitalization for congestive heart failure in BAV patients (BAV 7%, TAV 13%, p = 0.08) with significantly lower all-cause mortality in this cohort (BAV 1%, TAV 9%, p = 0.020). VARC-2 time-related valve safety (BAV 22%, TAV 20%, p = 0.60) was comparable; however, bioprosthetic valve thrombosis remained more common in BAV patients (BAV 7%, TAV 2%, p = 0.010, Hazard ratio 3.57 [95% confidence interval 1.26, 10.10]). After propensity score matching, only bioprosthetic valve thrombosis remained significantly different.

CONCLUSIONS

Safety and efficacy of the SAPIEN 3 balloon-expandable THV in BAV is comparable with TAV. Higher rates of bioprosthetic valve thrombosis require further investigation.

Late Clinical Valve Thrombosis After Transcatheter Aortic Valve Replacement Despite Non-Vitamin K Anticoagulant

This study presents the case of a late clinical leaflet thrombosis 1.5 years after percutaneous aortic valve replacement, despite adequate non-vitamin K anticoagulant therapy. Optimal antithrombotic therapy after transcatheter aortic valve replacement remains undetermined. After switching to vitamin K antagonist therapy, complete resolution occurred at 3 months follow-up. (Level of Difficulty: Intermediate.).

Transcatheter aortic valve thrombosis: Data from a French multicenter cohort analysis

OBJECTIVES

To evaluate the effectiveness of anticoagulant therapies in patients with clinical transcatheter heart valve (THV) thrombosis, to describe complications, and to assess their risk profile was the objectives.

BACKGROUND

Little research has been conducted on clinical THV thrombosis.

METHODS

Patients with clinical THV thrombosis were identified based on greater than 50% increased transvalvular gradient on transthoracic echocardiogram confirmed by 4-dimensional computed tomography, transesophageal echocardiogram, or regression with anticoagulant therapy. A cohort free from thrombosis for more than 1,100 days postprocedure was used for comparison.

RESULTS

Fifty-four patients with clinical THV thrombosis were identified. Most subjects (98.1%) received anticoagulant therapy which was effective (≥50% reduction in transvalvular gradient or return to postprocedure value) in 96%. The rate of serious hemodynamic or embolic complications in the thrombosis population was 31.5%. A multivariate analysis of subjects with and without thrombosis indicated a significantly increased risk of thrombosis from preexisting thrombocytopenia (odds ratio [OR] 9.96), absence of predilatation (OR = 5.67), renal insufficiency (OR = 4.84), and >10 mmHg mean transvalvular gradient postprocedure (OR = 3.36). No recurrence of thrombosis was identified during on average 685 days follow-up.

CONCLUSIONS

These data, from one of the largest cohorts with clinical THV thrombosis confirm anticoagulants appear effective. The rate of serious associated complications was high. The findings underline the importance of recognizing risk factors for thrombosis.

How to Image and Manage Prosthesis-Related Complications After Transcatheter Aortic Valve Replacement

PURPOSE OF REVIEW

In this review, we provide an overview of potential prosthesis - related complications after transcatheter aortic valve replacement, their incidences, the imaging modalities best suited for detection, and possible strategies to manage these complications.

RECENT FINDINGS

Therapy for severe aortic valve stenosis requiring intervention has increasingly evolved toward transcatheter aortic valve replacement over the past decade, and the number of procedures performed has increased steadily in recent years. As more and more centers favor a minimalistic approach and largely dispense with general anesthesia and intra-procedural imaging by transesophageal echocardiography, post-procedural imaging is becoming increasingly important to promptly detect dysfunction of the transcatheter valve and potential complications. Complications after transcatheter aortic valve replacement must be detected immediately in order to initiate adequate therapeutic measures, which require a profound knowledge of possible complications that may occur after transcatheter aortic valve replacement, the imaging modalities best suited for detection, and available treatment options.

Risk of Stroke After Transcatheter Aortic Valve Implantation: Epidemiology, Mechanism, and Management

BACKGROUND

Transcatheter aortic valve implantation (TAVI) has become an established and increasingly used approach for management of severe symptomatic aortic stenosis, showing similar or even superior outcomes compared with standard surgical aortic valve replacement (SAVR). Stroke after TAVI is a relatively rare, but serious complication, associated with potential prolonged disability and increased mortality.

AREAS OF UNCERTAINTY

The overall incidence of 30-day stroke in TAVI patients is 3%-4%, but varies between different trials. Initial data suggested a higher risk of stroke after TAVI when compared with SAVR. The association between subclinical leaflet thrombosis and cerebral embolism, presented as stroke, transient ischemic accident, or silent cerebral ischemia is not entirely elucidated yet. Moreover, TAVI for severe bicuspid aortic stenosis is a relatively new issue, bicuspid anatomy being initially excluded from the pivotal clinical trials investigating TAVI procedure. Efficient stroke prevention strategies are under investigation.

DATA SOURCES

In the present manuscript, we used the available published data from the most relevant clinical trials, registries, and meta-analysis of patients from different risk categories who underwent TAVI or SAVR.

THERAPEUTIC ADVANCES

Predictors of acute stroke are mainly procedure related. Technological development, improvements in bioprosthesis valve delivery catheters, and implantation technique may explain the decrease of stroke over the years since the beginning of TAVI procedures.

CONCLUSIONS

The overall evidences confirm similar or lower rate of stroke in TAVI versus SAVR. Risk predictors for acute stroke after TAVI are generally related to procedural factors, whereas late stroke is mainly associated with patient characteristics, with a variable impact on cognitive function. The optimal choice for the antithrombotic treatment in TAVI for stroke prevention is yet to be determined. Current data do not support routine use of cerebral embolic protection devices during TAVI.

Usefulness of Antiplatelet Therapy After Transcatheter Aortic Valve Implantation

The rationale for dual antiplatelet therapy (DAPT) after transcatheter aortic valve implantation (TAVI) is to facilitate endothelialization of metallic struts of the transcatheter heart valve and to prevent thrombosis that could lead to thromboembolic events. Based on expert consensus, current societal guidelines recommend DAPT for 1 to 6 months after TAVI with weak evidence. Although the pivotal TAVI trials mandated this regimen, the evidence for the efficacy of DAPT to prevent transcatheter heart valve thrombosis is limited to 3 small trials and a handful of observational studies. Multiple coronary trials have demonstrated that DAPT is associated with increased bleeding in comparison with single antiplatelet therapy, especially in elderly patients. TAVI patients are predominantly elderly and frequently have risk factors that predispose them to bleeding. Herein, we summarize the evidence for antiplatelet therapy after TAVI and explore the theoretical benefit of DAPT to prevent thromboembolic events versus the risk of increased bleeding.

Transcatheter Mitral Valve Replacement and Thrombosis: A Review

Mitral regurgitation is the most prevalent form of moderate or severe valve disease in developed countries. Surgery represents the standard of care for symptomatic patients with severe mitral regurgitation, but up to 50% of patients are denied surgery because of high surgical risk. In this context, different transcatheter options have been developed to address this unmet need. Transcatheter mitral valve replacement (TMVR) is an emergent field representing an alternative option in high complex contexts when transcatheter mitral valve repair is not feasible or suboptimal due to anatomical issues. However, TMVR is burdened by some device-specific issues (device malposition, migration or embolization, left ventricular outflow tract obstruction, hemolysis, thrombosis, stroke). Here we discuss the thrombotic risk of TMVR and current evidence about anticoagulation therapy after TMVR.

Clinical and Technical Challenges of Prosthesis-Patient Mismatch After Transcatheter Aortic Valve Implantation

Prosthesis-patient mismatch (PPM) is present when the effective area of a prosthetic valve inserted into a patient is inferior to that of a normal human valve; the hemodynamic consequence of a valve too small compared with the size of the patient's body is the generation of higher than expected transprosthetic gradients. Despite evidence of increased risk of short- and long-term mortality and of structural valve degeneration in patients with PPM after surgical aortic valve replacement, its clinical impact in patients subject to transcatheter aortic valve implantation (TAVI) is yet unclear. We aim to review and update on the definition and incidence of PPM after TAVI, and its prognostic implications in the overall population and in higher-risk subgroups, such as small aortic annuli or valve-in-valve procedures. Last, we will focus on the armamentarium available in order to reduce risk of PPM when planning a TAVI procedure.

Percutaneous versus Surgical Intervention for Severe Aortic Valve Stenosis: A Systematic Review

Aortic stenosis is a disease that is increasing in prevalence and manifests as decreased cardiac output, which if left untreated can result in heart failure and ultimately death. It is primarily a disease of the elderly who often have multiple comorbidities. The advent of transcatheter aortic valve therapies has changed the way we treat these conditions. However, long-term results of these therapies remain uncertain. Recently, there has been an increasing number of studies examining the role of both surgical aortic valve replacement and transcatheter aortic valve replacement. We therefore performed a systematic review using Ovid MEDLINE, Ovid Embase, and the Cochrane Library. Two investigators searched papers published between January 1, 2007, and to date using the following terms: "aortic valve stenosis," "aortic valve operation," and "transcatheter aortic valve therapy." Both strategies in aortic stenosis treatment highlighted specific indications alongside the pitfalls such as structural valve degeneration and valve thrombosis which have a bearing on clinical outcomes. We propose some recommendations to help clinicians in the decision-making process as technological improvements make both surgical and transcatheter therapies viable options for patients with aortic stenosis. Finally, we assess the role of finite element analysis in patient selection for aortic valve replacement. THVT and AVR-S are both useful tools in the armamentarium against aortic stenosis. The decision between the two treatment strategies should be best guided by a strong robust evidence base, ideally with a long-term follow-up. This is best performed by the heart team with the patient as the center of the discussion.