Percutaneous valve repair and replacement techniques

Edge-to-Edge Transcatheter Mitral Valve Repair Using PASCAL vs. MitraClip: A Systematic Review and Meta-Analysis

BACKGROUND

Transcatheter edge-to-edge repair (TEER) of the mitral valve (MV) can be performed using the PASCAL or MitraClip devices. Few studies offer a head-to-head outcome comparison of these two devices.

MATERIAL AND METHODS

PubMed, EMBASE, Cochrane Library, Clinicaltrials.gov and WHO's International Clinical Trials Registry Platform, from 1 January 2000 until 1 March 2023, were searched. Study protocol details were registered in the International Prospective Register of Systematic Reviews (PROSPERO ID: CRD42023405400). Randomized Controlled Trials and observational studies reporting head-to-head clinical comparison of PASCAL and MitraClip devices were eligible for selection. Patients with severe functional or degenerative mitral regurgitation (MR) who had undergone TEER of the MV with either PASCAL or MitraClip devices were included in the meta-analysis. Data from six studies (five observational and one randomized clinical trial) were extracted and analyzed. The main outcomes were a reduction in MR to 2+ or less, improvement of New York Heart Association (NYHA) and 30-day all-cause mortality. Peri-procedural mortality, success rate and adverse events were also compared.

RESULTS

Data from 785 and 796 patients that underwent TEER using PASCAL and MitraClip, respectively, were analyzed. Thirty-day all-cause mortality (Risk ratio [RR] = 1.51, 95% CI 0.79-2.89), MR reduction to maximum 2+ (RR = 1.00, 95% CI 0.98-1.02) and NYHA improvement (RR = 0.98, 95% CI 0.84-1.15) were similar in both device groups. Both devices had high and similar success rates (96.9% and 96.7% for the PASCAL and MitraClip group, respectively, p value = 0.91). MR reduction to 1+ or less at discharge was similar in both device groups (RR = 1.06, 95% CI 0.95-1.19). Composite peri-procedural and in-hospital mortality was 0.64% and 1.66% in the PASCAL and MitraClip groups, respectively (p value = 0.094). Rates of peri-procedural cerebrovascular accidents were 0.26% in PASCAL and 1.01% in MitraClip (p value = 0.108).

CONCLUSIONS

Both PASCAL and MitraClip devices have high success and low complication rates for TEER of the MV. PASCAL was not inferior to MitraClip in reducing the MR level at discharge.

Fatigue damage of collagenous tissues: experiment, modeling and simulation studies

Mechanical fatigue damage is a critical issue for soft tissues and tissue-derived materials, particularly for musculoskeletal and cardiovascular applications; yet, our understanding of the fatigue damage process is incomplete. Soft tissue fatigue experiments are often difficult and time-consuming to perform, which has hindered progress in this area. However, the recent development of soft-tissue fatigue-damage constitutive models has enabled simulation-based fatigue analyses of tissues under various conditions. Computational simulations facilitate highly controlled and quantitative analyses to study the distinct effects of various loading conditions and design features on tissue durability; thus, they are advantageous over complex fatigue experiments. Although significant work to calibrate the constitutive models from fatigue experiments and to validate predictability remains, further development in these areas will add to our knowledge of soft-tissue fatigue damage and will facilitate the design of durable treatments and devices. In this review, the experimental, modeling, and simulation efforts to study collagenous tissue fatigue damage are summarized and critically assessed.

Simulation of long-term fatigue damage in bioprosthetic heart valves: effects of leaflet and stent elastic properties

One of the major failure modes of bioprosthetic heart valves (BHVs) is noncalcific structural deterioration due to fatigue of the tissue leaflets; yet, the mechanisms of fatigue are not well understood. BHV durability is primarily assessed based on visual inspection of the leaflets following accelerated wear testing. In this study, we developed a computational framework to simulate BHV leaflet fatigue, which is both efficient and quantitative, making it an attractive alternative to traditional accelerated wear testing. We utilize a phenomenological soft tissue fatigue damage model developed previously to describe the stress softening and permanent set of the glutaraldehyde-treated bovine pericardium leaflets in BHVs subjected to cyclic loading. A parametric study was conducted to determine the effects of altered leaflet and stent elastic properties on the fatigue of the leaflets. The simulation results show that heterogeneity of the leaflet elastic properties, poor leaflet coaptation, and little stent-tip deflection may accelerate leaflet fatigue, which agrees with clinical findings. Therefore, the developed framework may be an invaluable tool for evaluating leaflet durability in new tissue valve designs, including traditional BHVs as well as new transcatheter valves.

Modeling of long-term fatigue damage of soft tissue with stress softening and permanent set effects

One of the major failure modes of bioprosthetic heart valves is non-calcific structural deterioration due to fatigue of the tissue leaflets. Experimental methods to characterize tissue fatigue properties are complex and time-consuming. A constitutive fatigue model that could be calibrated by isolated material tests would be ideal for investigating the effects of more complex loading conditions. However, there is a lack of tissue fatigue damage models in the literature. To address these limitations, in this study, a phenomenological constitutive model was developed to describe the stress softening and permanent set effects of tissue subjected to long-term cyclic loading. The model was used to capture characteristic uniaxial fatigue data for glutaraldehyde-treated bovine pericardium and was then implemented into finite element software. The simulated fatigue response agreed well with the experimental data and thus demonstrates feasibility of this approach.

Simulation Based Design and Evaluation of a Transcatheter Mitral Heart Valve Frame

In certain populations, open heart surgery to replace a diseased mitral valve is not an option, leaving percutaneous delivery a viable alternative. However, a surgical transcatheter based delivery of a metallic support frame incorporating a tissue derived valve puts considerable constraints on device specifications. Expansion to a large diameter from the catheter diameter without mechanical fracture involves advanced device design and appropriate material processing and selection. In this study, a new frame concept is presented with a desirable feature that incorporates wings that protrude during expansion to establish adequate fixation. Expansion characteristics of the design in relation to annulus fixation were quantified through finite element analysis predictions of the frame wing span and angles. Computational modeling and simulation was used to identify many favorable design features for the transcatheter mitral valve frame and obtain desired expansion diameters (35-45mm), acceptable radial stiffness (2.7N/mm), and ensure limited risk of failure based on predicted plastic deformations.

Immediate results of percutaneous trans-luminal mitral commissurotomy in pregnant women with severe mitral stenosis

Background

Valvular heart diseases and mainly rheumatic heart diseases complicate about 1% of pregnancies. During pregnancy physiological hemodynamic changes of the circulation are the main cause of mitral stenosis (MS) decompensation. Prior to introduction of percutaneous mitral balloon commissuroplasty (PTMC), surgical comissurotomy was the preferred method of treatment in patients with refractory symptoms. PTMC is an established non-surgical treatment of rheumatic mitral stenosis. The study aimed to assess the safety and efficacy of PTMC in pregnant women with severs mitral stenosis.

Material and Method

Thirty three consecutive patients undergoing PTMC during pregnancy enrolled in this prospective study. Mitral valve area (MVA), transmitral valve gradient (MVG), and severity of mitral regurgitation (MR) were assessed before and 24 hour after the procedure by transthoracic and transesophageal echocardiography. Mitral valve morphology was evaluated before the procedure using Wilkin’s criteria. Patient followed for one month and neonates monitored for weight and height and adverse effect of radiation.

Result

Mitral valve area increased from 0.83 ± 0.13 cm² to 1.38 ± 0.29 cm² (P = 0.007). Mean gradient of mitral valve decreased from 15.5 ± 7.4 mmHg to 2.3 ± 2.3 mmHg (P = <0.001). Pulmonary artery pressure decreased from 65.24 ± 17.9 to 50.45 ± 15.33 (P = 0.012). No maternal death, abortion, intrauterine growth restriction was observed and only one stillbirth occurred.

Conclusion

PTMC in pregnant women has favorable outcome and no harmful effect on children noted.

Advances in percutaneous treatment for adult valvular heart disease

Valvular heart disease occurs in 2-3% of the general population with an increase in prevalence with advancing age. The aetiology of valvular heart disease has evolved in recent decades with degenerative aortic and mitral valve disease supplanting rheumatic heart disease as a primary cause. The common valve lesions to be discussed in this article are aortic stenosis and mitral regurgitation. The traditional approach to calcific aortic stenosis when either symptoms or left ventricular impairment develops is surgical aortic valve replacement and it remains a treatment with excellent outcomes. In recent years there has been interest in less invasive approaches, including percutaneous and transapical aortic valve implantation. With refinements in technology these approaches are becoming a potential treatment option, primarily for high-risk patients who may otherwise be unsuitable for traditional open surgical treatment. Catheter-based approaches for mitral valve disease are also evolving. Mitral regurgitation may often be the result of mitral annular dilatation seen in patients with an enlarged left ventricle or left atrium. Percutaneous implantation of a constricting device in the coronary sinus, which lies in close proximity to the mitral annulus, results in a change to the geometry of the mitral valve and reduced regurgitation. Another technique in patients with degenerative mitral regurgitation is the endovascular edge-to-edge repair in which coaptation of the mitral valve leaflets can be improved with a percutaneously deployed clip. Small patient series indicate that these new techniques are promising. As such, advances in percutaneous interventional and surgical approaches have the potential to further improve outcomes for selected patients with valvular heart disease.

Valvular heart disease: focus on women

Calcific aortic stenosis is a disease of the elderly and aortic valve replacement should always be considered for severe symptomatic disease; comorbidities, not age, determine surgical risk. Aortic regurgitation imposes a pressure and volume load on the left ventricle so that close monitoring is needed to identify patients at risk for irreversible left ventricular dysfunction, although symptoms are the most common indication for valve replacement. Early intervention now is recommended for rheumatic mitral stenosis due to the effectiveness of percutaneous balloon valvotomy. Earlier intervention also may be considered in selected patients with mitral regurgitation at experienced centers when valve anatomy is favorable for a successful repair. Semiquantitative descriptors of regurgitation as mild, moderate, or severe are no longer adequate; management of adults with chronic valve disease requires quantitation of both the severity of valve disease and of left ventricular size and systolic function.

Percutaneous transarterial aortic valve replacement in selected high-risk patients with aortic stenosis

BACKGROUND

Percutaneous aortic valve replacement represents an endovascular alternative to conventional open heart surgery without the need for sternotomy, aortotomy, or cardiopulmonary bypass.

METHODS AND RESULTS

Transcatheter implantation of a balloon-expandable stent valve using a femoral arterial approach was attempted in 50 symptomatic patients with severe aortic stenosis in whom there was a consensus that the risks of conventional open heart surgery were very high. Valve implantation was successful in 86% of patients. Intraprocedural mortality was 2%. Discharge home occurred at a median of 5 days (interquartile range, 4 to 13). Mortality at 30 days was 12% in patients in whom the logistic European System for Cardiac Operative Risk Evaluation risk score was 28%. With experience, procedural success increased from 76% in the first 25 patients to 96% in the second 25 (P=0.10), and 30-day mortality fell from 16% to 8% (P=0.67). Successful valve replacement was associated with an increase in echocardiographic valve area from 0.6+/-0.2 to 1.7+/-0.4 cm2. Mild paravalvular regurgitation was common but was well tolerated. After valve insertion, there was a significant improvement in left ventricular ejection fraction (P<0.0001), mitral regurgitation (P=0.01), and functional class (P<0.0001). Improvement was maintained at 1 year. Structural valve deterioration was not observed with a median follow-up of 359 days.

CONCLUSIONS

Percutaneous valve replacement may be an alternative to conventional open heart surgery in selected high-risk patients with severe symptomatic aortic stenosis.