Revolutionizing cardiovascular care: the power of histotripsy

Histotripsy, an innovative ultrasonic technique, is poised to transform the landscape of cardiovascular disease management. This review explores the multifaceted applications of histotripsy across various domains of cardiovascular medicine. In thrombolysis, histotripsy presents a non-invasive, drug-free, and precise method for recanalizing blood vessels obstructed by clots, minimizing the risk of vessel damage and embolism. Additionally, histotripsy showcases its potential in congenital heart defect management, offering a promising alternative to invasive procedures by creating intracardiac communications noninvasively. For patients with calcified aortic stenosis, histotripsy demonstrates its effectiveness in softening calcified bioprosthetic valves, potentially revolutionizing valve interventions. In the realm of arrhythmias, histotripsy could play an important role in scar-based ventricular tachycardia ablation, eliminating channel-like isthmuses of slowly conducting myocardium. Histotripsy`s potential applications also extend to structural heart interventions, enabling the safe sectioning of basal chordae and potentially addressing mitral regurgitation. Furthermore, it showcases its versatility by safely generating ventricular septal defects, providing a non-invasive means of creating intracardiac communications in neonates with congenital heart disease. Yet, most supporting studies are in-vitro or animal studies and there are possible challenges in translating experimental data on cardiac histotripsy to the clinical level. As histotripsy continues to evolve and mature, its remarkable potential in cardiovascular disease management holds promise for improving patient outcomes and reducing the burden of invasive procedures in the field of cardiology.

Transoesophageal echocardiography-guided 'primary' valve-in-valve technique in cardiogenic shock: a case report

Background

Transcatheter aortic valve implantation inside a previously implanted bioprosthesis is an alternative treatment for patients with degenerated surgical aortic bioprosthesis (AB) at high surgical risk. Pre-operative computed tomography (CT) scan provides essential information to the procedure planning, although in case of acute presentation it is not always feasible.

Case summary

A 32-year-old man with history of surgical treatment of aortic coarctation and Bio-Bentall procedure was transferred to our department in cardiogenic shock with a suspected diagnosis of acute myocarditis. A transthoracic echocardiogram (TTE) revealed a severely impaired biventricular function and AB degeneration causing severe stenosis. It was decided to undertake an urgent trans-apical valve-in-valve (ViV) procedure. Due to haemodynamic instability, a preoperative CT scan was not performed and transoesophageal echocardiography (TOE) was the main intraprocedural guiding imaging technique. Neither intraprocedural nor periprocedural complications occurred. Serial post-procedural TTE exams showed good functioning of the bioprosthesis and progressive improvement of left ventricular ejection fraction. Patient was discharged from the hospital 8 days after the intervention.

Discussion

A patient with cardiogenic shock due to severe degeneration of the AB was treated with urgent transapical ViV procedure. In this case, where urgent ViV technique was needed, TOE appeared to be a crucial alternative to CT scan and allowed us to perform a successful procedure.

In Vitro Study of a Stentless Aortic Bioprosthesis Made of Bacterial Cellulose

PURPOSE

The paper present findings from an in vitro experimental study of a stentless human aortic bioprosthesis (HAB) made of bacterial cellulose (BC). Three variants of the basic model were designed and tested to identify the valve prosthesis with the best performance parameters. The modified models were made of BC, and the basic model of pericardium.

METHODS

Each model (named V1, V2 and V3) was implanted into a 90 mm porcine aorta. Effective Orifice Area (EOA), rapid valve opening time (RVOT) and rapid valve closing time (RVCT) were determined. The flow resistance of each bioprosthesis model during the simulated heart systole, i.e. for the mean differential pressure (ΔP) at the time of full valve opening was measured. All experimental specimens were exposed to a mean blood pressure (MBP) of 90.5 ± 2.3 mmHg.

RESULTS

The V3 model demonstrated the best performance. The index defining the maximum opening of the bioprosthesis during systole for models V1, V2 and V3 was 2.67 ± 0.59, 2.04 ± 0.23 and 2.85 ± 0.59 cm2, respectively. The mean flow rate through the V3 valve was 5.7 ± 1, 6.9 ± 0.7 and 8.9 ± 1.4 l/min for stroke volume (SV) of 65, 90 and 110 mL, respectively. The phase of immediate opening and closure for models V1, V2 and V3 was 8, 7 and 5% of the cycle duration, respectively. The mean flow resistance of the models was: 4.07 ± 2.1, 4.28 ± 2.51 and 5.6 ± 2.32 mmHg.

CONCLUSIONS

The V3 model of the aortic valve prosthesis is the most effective. In vivo tests using BC as a structural material for this model are recommended. The response time of the V3 model to changed work conditions is comparable to that of a healthy human heart. The model functions as an aortic valve prosthesis in in vitro conditions.

Transcatheter Valve-in-Valve Implantation With a Novel Balloon-Expandable Device in Patients With Bioprosthetic Heart Valve Failure: A Case Series

Trans-catheter valve-in-valve (ViV) is a treatment option for patients affected by bioprosthetic heart valve (BHV) failure. Both aortic and mitral ViV procedures present several challenges compared to native valve replacement. To date, no data concerning the balloon-expandable MyVal (Meril, Vapi, India) trans-catheter heart valve (THV) use in ViV procedure have been provided. In this case series, we described for the first time its use in five different BHV failures.

Natural History of a Carpentier-Edwards Pericardial Aortic Valve Replaced after 25 Years for Structural Valve Degeneration

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SVD is a main limitation of bioprostheses.

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Routine use of bioprostheses in younger patients (<60 years of age) is controversial.

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Data on the durability of surgical aortic bioprostheses beyond 20 years are limited.

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We report exceptional durability of an aortic bioprosthesis replaced after 25 years.

Benefits of rapid deployment aortic valve replacement with a mini upper sternotomy

BACKGROUND

Surgical aortic valve replacement (AVR) is currently deemed the gold standard of care for patients with severe aortic stenosis. Currently, most AVRs are safely performed through a full median sternotomy approach. With an increasingly elderly and high-risk patient population, major advances in valve technology and surgical technique have been introduced to reduce perioperative risk and post-operative complications associated with the full sternotomy approach, in order to ensure surgical AVR remains the gold standard. For example, minimally invasive approaches (most commonly via mini sternotomy) have been developed to improve patient outcomes. The advent of rapid deployment valve technology has also been shown to improve morbidity and mortality by reducing cardiopulmonary bypass and aortic cross-clamp times, as well as facilitating the use of minimal access approaches. Rapid deployment valves were introduced into our department at the Royal Infirmary of Edinburgh in 2014. The aim of this study is to investigate if utilising the combination of rapid deployment valves and a mini sternotomy minimally invasive approach resulted in improved outcomes in various patient subgroups.

METHODS

Over a 3-year period, we identified 714 patients who underwent isolated AVR in our centre. They were divided into two groups: 61 patients (8.5%) were identified who received rapid deployment AVR via J-shaped mini upper sternotomy (MIRDAVR group), whilst 653 patients (91.5%) were identified who received either a full sternotomy (using a conventional prosthesis or rapid deployment valve) or minimally invasive approach using a conventional valve (CONVAVR group). We retrospectively analysed data from our cardiac surgery database, including pre-operative demographics, intraoperative times and postoperative outcomes. Outcomes were also compared in two different subgroups: octogenarians and high-risk patients.

RESULTS

Pre-operative demographics showed that there were significantly more female and elderly patients in the MIRDAVR group. The MIRDAVR group had significantly reduced cardiopulmonary bypass (63.7 min vs. 104 min, p = 0.0001) and aortic cross-clamp times (47.3 min vs. 80.1 min, p = 0.0001) compared to the CONVAVR group. These results were particularly significant in the octogenarian population, who also had a reduced length of ICU stay (30.9 h vs. 65.6 h, p = 0.049). In high-risk patients (i.e. logistic EuroSCORE I > 10%), minimally invasive-rapid deployment aortic valve replacement is still beneficial and is also characterized by significantly shorter cardiopulmonary bypass time (69.1 min vs. 96.1 min, p = 0.03). However, post-operative correlations, such as length of ICU stay, become no more significant, likely due to serious co-morbidities in this patient group.

CONCLUSION

We have demonstrated that minimally invasive rapid deployment aortic valve replacement is associated with significantly reduced cardiopulmonary bypass and aortic cross-clamp times. This correlation is much stronger in the octogenarian population, who were also found to have significantly reduced length of ICU stay. Our study raises the suggestion that this approach should be utilised more frequently in clinical practice, particularly in octogenarian patients.

Valve-in-valve transcatheter aortic valve implantation after failed surgically implanted aortic bioprosthesis versus native transcatheter aortic valve implantation for aortic stenosis: Data from a nationwide analysis

BACKGROUND

Valve-in-valve transcatheter aortic valve implantation (TAVI) has emerged as a treatment for aortic bioprosthesis failure in case of prohibitive risk for redo surgery. However, clinical evaluation of valve-in-valve TAVI remains limited by the number of patients analysed.

AIM

To evaluate outcomes of valve-in-valve TAVI compared with native aortic valve TAVI at a nationwide level in France.

METHODS

Based on the French administrative hospital discharge database, the study collected information for all consecutive patients treated with TAVI for aortic stenosis or with isolated valve-in-valve TAVI for aortic bioprosthesis failure between 2010 and 2019. Propensity score matching was used for the analysis of outcomes.

RESULTS

A total of 44,218 patients were found in the database. After matching on baseline characteristics, 2749 patients were analysed in each arm. At 30 days, no significant differences were observed regarding the occurrence of major clinical events (composite of cardiovascular mortality, all-cause stroke, myocardial infarction, major or life-threatening bleeding and conversion to open heart surgery) (odds ratio [OR] 0.83, 95% confidence interval [CI] 0.68-1.01; P=0.32). During follow-up (mean 516 days), the combined endpoint of cardiovascular death, all-cause stroke or rehospitalization for heart failure was not different between the valve-in-valve TAVI and native TAVI groups (RR 1.03, 95% CI 0.94-1.13; P=1.00).

CONCLUSION

We observed that valve-in-valve TAVI was associated with good short- and long-term outcomes. No significant differences were observed compared with native valve TAVI regarding clinical follow-up.

Hemodynamics and reverse remodeling associated with Mosaic, Perimount and Trifecta aortic bioprostheses

Introduction: The implantation rate of aortic bioprostheses is increasing. Their durability has improved to some extent over the years and they allow for future transcatheter valve-in-valve deployment. In the lack of long term follow up, their hemodynamic profile, i.e. transvalvular mean pressure gradient and effective orifice area indexed, and the associated left ventricular reverse remodeling indexed are useful surrogates for clinical outcomes. Areas covered: A systematic review of the literature was conducted by searching Medline, Cochrane, Scielo, Embase databases, and grey literature until July 2018 for articles that perform comparisons among the three most popular aortic bioprostheses. Six randomized and 12 non-randomized studies were included with 565 patients receiving a Mosaic, 1334 a Perimount and 557 a Trifecta valve. These articles are heterogeneous but they allow the meta-analytic comparison of the abovementioned outcomes. Expert opinion: Compared to the Perimount valve, the Mosaic is hemodynamically inferior, while the Trifecta is superior. Despite these statistically significant differences, the left ventricular mass regression indexed, that is indicative of reverse remodeling, was comparable in all groups. All patients were similarly benefited. The predilection among these valves is fueled by their hemodynamic profile but not supported by the comparable reverse remodeling.

Effect of bioprostheses anti-calcification treatment: comparative follow-up between Mitroflow LX and Magna pericardial xenografts using a propensity score-weighted analysis

Objectives

The efficacy of anti-calcification treatment of bioprosthetic heart valves remains unclear. The aim of this study was to compare the clinical outcomes between Mitroflow LX valve, without anti-calcification treatment, and the Carpentier-Edwards Perimount Magna (P-Magna), with anti-calcification treatment.

Methods

Between 2005 and 2012, 625 consecutive patients underwent aortic valve replacement either with a Mitroflow LX ( n  = 329) or a P-Magna ( n  = 296). Variables regarding patient-related risk factors and operative data were accounted for an inverse probability of treatment weighting analysis. Then, adjusted survival outcomes and the rate of structural valve disease (SVD) were assessed for each group.

Results

Mean follow-up times were 4.1 ± 2.29 years and 3.9 ± 2.63 years, respectively ( P  = 0.34). Adjusted overall survival rate was higher in the P-Magna group than in the Mitroflow LX group at 8 years (69.1% vs 51.9%, respectively) [HR = 1.44, 95% CI: 1.01 to 2.06; P  = 0.0467]. Similarly, the 8-year cardiac-related survival rate was also higher in the P-Magna group [HR = 1.99, 95% CI: 1.19 to 3.32; P  = 0.0083]. One patient (0.8%) with P-Magna and 23 patients (18.5%) with Mitroflow LX group developed SVD (0.24% per patient-year vs 4.5% per patient-year, respectively; P  < 0.001). At 5 and 8 years, valve-related survival rates did not differ significantly between both groups [HR = 1.67, 95% CI: 0.95 to 2.95; P  = 0.075].

Conclusions

The P-Magna prosthesis showed significantly better overall and cardiac-related survival than the Mitroflow LX. The higher early SVD and reoperation rates seen with the Mitroflow LX prosthesis did not impact negatively on valve-related survival.

Significant intra-valvular pressure loss across EPIC SUPRA and perimount magna supra-annular designed aortic bioprostheses in patients with normal aortic size

Doppler-derived trans-prosthetic gradients are higher and the estimated effective valve area is smaller than the catheter-derived and directly measured hemodynamic values, mostly due to pressure recovery phenomenon. Pressure recovery to a varying extent is common to all prosthetic heart valves including bioprostheses. Pressure recovery-related differences are usually small except in patients with bileaflet metallic prosthesis, wherein high-pressure local jets across central orifice have been documented since long back and also in patients with narrow aortic root. We describe two patients with normally functioning stented aortic bioprostheses with supra-annular design (EPIC SUPRA and PERIMOUNT MAGNA), wherein very high trans-prosthetic gradients and critically reduced estimated effective valve orifice areas in presence of normal aortic size were consistently recorded over long periods of follow-up. The valve leaflets, however had normal excursion, were thin, opened with a triangular or oblong shape and had expected geometric valve area (1.7 and 1.6 cm² respectively) measured by 3D trans-oesophageal echocardiographic planimetry. Pressure recovery upstream the valves accounted for 20% and 12% of total pressure gradients respectively. Dominant site for pressure drop was intra-valvular (75–85%). Such a phenomenon has not been reported in vivo for these two valve designs.