Will there ever be a Food and Drug Administration-approved device for transcatheter paravalvular leak closure?

Computational Fluid Dynamics Simulations of Mitral Paravalvular Leaks in Human Heart

In recent years, computational fluid dynamics (CFD) has been extensively used in biomedical research on heart diseases due to its non-invasiveness and relative ease of use in predicting flow patterns inside the cardiovascular system. In this study, a modeling approach involving CFD simulations was employed to study hemodynamics inside the left ventricle (LV) of a human heart affected by a mitral paravalvular leak (PVL). A simplified LV geometry with four PVL variants that varied in shape and size was studied. Predicted blood flow parameters, mainly velocity and shear stress distributions, were used as indicators of how presence of PVLs correlates with risk and severity of hemolysis. The calculations performed in the study showed a high risk of hemolysis in all analyzed cases, with the maximum shear stress values considerably exceeding the safe level of 300 Pa. Results of our study indicated that there was no simple relationship between PVL geometry and the risk of hemolysis. Two factors that potentially played a role in hemolysis severity, namely erythrocyte exposure time and the volume of fluid in which shear stress exceeded a critical value, were not directly proportional to any of the characteristic geometrical parameters (shape, diameters, circumference, area, volume) of the PVL channel. Potential limitations of the proposed simplified approach of flow analysis are discussed, and possible modifications to increase the accuracy and plausibility of the results are presented.

Sutureless aortic valve prostheses

Conventional surgical aortic valve replacement (AVR) is the 'gold standard' for treatment of severe or symptomatic aortic valve stenosis. The increasing age of patients and increasing comorbidities has led to the development of procedures to minimise operative time and reduce risks of surgery. One method of reducing operative times is the use of sutureless aortic valves (SU-AVR). We examine the current literature surrounding the use of SU-AVR. Alternatives to AVR are SU-AVR, sometimes referred to as rapid deployment valves, or transcatheter aortic valve implantation (TAVI). TAVI has been demonstrated to be superior over medical therapy in patients deemed inoperable and non-inferior in high and intermediate-risk patients compared with surgical AVR. However, the lack of excision of the calcified aortic valve and annulus raises concerns regarding long-term durability and possibly thromboembolic complications. TAVI patients have increased rates of paravalvular leaks, major vascular complications and pacemaker implantation when compared with conventional AVR. SU-AVR minimises the need for suturing, leading to reduced operative times, while enabling complete removal of the calcified valve. The increase in use of SU-AVR has been mostly driven by minimally invasive surgery. Other indications include patients with a small and/or calcified aortic root, as well as patients requiring AVR and concomitant surgery. SU-AVR is associated with decreased operative times and possibly improved haemodynamics when compared with conventional AVR. However, this has to be weighed against the increased risk of paravalvular leak and pacemaker implantation when deciding which prosthesis to use for AVR.

Percutaneous management of paravalvular leaks

Paravalvular leak (PVL) is a complication that occurs in 5-17% of patients after surgical prosthetic valve implantation. Whereas PVLs can be benign, some PVLs are associated with substantial morbidity and mortality. Percutaneous closure using occluders specifically designed to improve closure and reduce procedural complications has now become the first-line treatment for PVL. In this Review, we first detail the frequency and clinical consequences of PVL closure. The role of cardiac imaging in the assessment and management of PVL, including echocardiographic imaging and adjunctive techniques such as CT, is then discussed, together with important considerations for the percutaneous closure of PVL, such as access site and device selection. Finally, we summarize the clinical evidence for percutaneous closure of PVL, including large national registries from Ireland, Spain and the UK, as well as head-to-head data comparing this procedure with surgical closure.

Meta-analysis Comparing Transcatheter and Surgical Treatments of Paravalvular Leaks

Percutaneous paravalvular leak (PVL) closure has emerged as a feasible alternative to redo valve surgery. However, comparative data on percutaneous and surgical treatment of PVL are scarce. We performed a systematic review and a meta-analysis of studies on percutaneous and surgical treatments of PVL. Of the 2,267 studies screened, 22 eligible studies were analyzed. Primary end points were technical success, 30-day mortality, stroke, and length of stay. Secondary end points were 1-year mortality, readmission for heart failure, reoperation, and symptomatic improvement at follow-up. A total of 2,373 patients were included, of whom 1,511 (63.7%) underwent percutaneous closure. Technical success was higher with surgery (96.7% vs 72.1%, odds ratio [OR] 9.7, p <0.001) but at the cost of higher 30-day mortality (8.6% vs 6.8%, OR 1.90, p <0.001), a trend toward higher stroke (3.3% vs 1.4%, OR 1.94, p = 0.069), and longer hospitalizations. However, surgery was associated with similar 1-year mortality (17.3% vs 17.2%, OR 1.07, p = 0.67), reoperation (9.1% vs 9.9%, OR 0.72, p = 0.1), readmission for heart failure (13.3% vs 26.4%, OR 0.51, p = 0.29), and improvement in New York Heart Association classification (67.4% vs 56%, OR 1.37, p = 0.74), compared with percutaneous closure. A sensitivity analysis including comparative studies only yielded similar results. Surgical treatment of PVL achieves higher technical success rates but is associated with higher early morbidity and mortality compared with percutaneous closure. Nevertheless, mortality rates and clinical efficacy parameters were similar at midterm with both procedures. Further studies are warranted to identify the ideal management approach to patients with symptomatic PVL.

Percutaneous aortic leak closure in a small and frail annulus after double heart valve replacement

: Paravalvular leak (PVL) is an uncommon but serious complication associated with the implantation of prosthetic valves. Following aortic valve replacement, up to 5% of patients affected by PVL develop clinical symptoms of heart failure, hemolysis or both. Percutaneous treatment of PVL has emerged instead of conventional surgery, as a well tolerated and less invasive procedure but remains a challenge. We present the case of a young woman with mechanical aortic and mitral prostheses, who presented surgical aortic PVL caused by a serious frailty of native annulus, became symptomatic after 5 months and was successfully percutaneously treated with an Amplatzer Duct Occluder device.

Percutaneous Device Closure of Paravalvular Leak: Combined Experience From the United Kingdom and Ireland

BACKGROUND

Paravalvular leak (PVL) occurs in 5% to 17% of patients following surgical valve replacement. Percutaneous device closure represents an alternative to repeat surgery.

METHODS

All UK and Ireland centers undertaking percutaneous PVL closure submitted data to the UK PVL Registry. Data were analyzed for association with death and major adverse cardiovascular events (MACE) at follow-up.

RESULTS

Three hundred eight PVL closure procedures were attempted in 259 patients in 20 centers (2004-2015). Patient age was 67±13 years; 28% were female. The main indications for closure were heart failure (80%) and hemolysis (16%). Devices were successfully implanted in 91% of patients, via radial (7%), femoral arterial (52%), femoral venous (33%), and apical (7%) approaches. Nineteen percent of patients required repeat procedures. The target valve was mitral (44%), aortic (48%), both (2%), pulmonic (0.4%), or transcatheter aortic valve replacement (5%). Preprocedural leak was severe (61%), moderate (34%), or mild (5.7%) and was multiple in 37%. PVL improved postprocedure (P<0.001) and was none (33.3%), mild (41.4%), moderate (18.6%), or severe (6.7%) at last follow-up. Mean New York Heart Association class improved from 2.7±0.8 preprocedure to 1.6±0.8 (P<0.001) after a median follow-up of 110 (7-452) days. Hospital mortality was 2.9% (elective), 6.8% (in-hospital urgent), and 50% (emergency) (P<0.001). MACE during follow-up included death (16%), valve surgery (6%), late device embolization (0.4%), and new hemolysis requiring transfusion (1.6%). Mitral PVL was associated with higher MACE (hazard ratio [HR], 1.83; P=0.011). Factors independently associated with death were the degree of persisting leak (HR, 2.87; P=0.037), New York Heart Association class (HR, 2.00; P=0.015) at follow-up and baseline creatinine (HR, 8.19; P=0.001). The only factor independently associated with MACE was the degree of persisting leak at follow-up (HR, 3.01; P=0.002).

CONCLUSION

Percutaneous closure of PVL is an effective procedure that improves PVL severity and symptoms. Severity of persisting leak at follow-up is independently associated with both MACE and death. Percutaneous closure should be considered as an alternative to repeat surgery.