Finite element modeling with patient-specific geometry to assess clinical risks of percutaneous pulmonary valve implantation.

BACKGROUND: Percutaneous pulmonary valve implantation (PPVI) is a non-surgical treatment for right ventricular outflow tract (RVOT) dysfunction. During PPVI, a stented valve, delivered via catheter, replaces the dysfunctional pulmonary valve. Stent oversizing allows valve anchoring within the RVOT, but overexpansion can intrude on the surrounding structures. Potentially dangerous outcomes include aortic valve insufficiency (AVI) from aortic root (AR) distortion and myocardial ischemia from coronary artery (CA) compression. Currently, risks are evaluated via balloon angioplasty/sizing before stent deployment. Patient-specific finite element (FE) analysis frameworks can improve pre-procedural risk assessment, but current methods require hundreds of hours of high-performance computation. METHODS: We created a simplified method to simulate the procedure using patient-specific FE models for accurate, efficient pre-procedural PPVI (using balloon expandable valves) risk assessment. The methodology was tested by retrospectively evaluating the clinical outcome of 12 PPVI candidates. RESULTS: Of 12 patients (median age 14.5 years) with dysfunctional RVOT, 7 had native RVOT and 5 had RV-PA conduits. Seven patients had undergone successful RVOT stent/valve placement, three had significant AVI on balloon testing, one had left CA compression, and one had both AVI and left CA compression. A model-calculated change of more than 20% in lumen diameter of the AR or coronary arteries correctly predicted aortic valve sufficiency and/or CA compression in all the patients. CONCLUSION: Agreement between FE results and clinical outcomes is excellent. Additionally, these models run in 2-6 min on a desktop computer, demonstrating potential use of FE analysis for pre-procedural risk assessment of PPVI in a clinically relevant timeframe.

[Left Ventricular Outflow Tract Obstruction After Transcatheter Aortic Valve Replacement due to Pannus Formation].

We experienced a case of surgical aortic valve re-replacement due to structural valve deterioration caused by pannus formation 4 years after transcatheter aortic valve replacement( TAVR). The patient underwent surgery because the mean transvalvular pressure gradient increased to 48 mmHg on echocardiography. Contrast-enhanced computed tomography (CT) was useful for predicting the site of adhesion to surrounding tissue preoperatively and exploring the presence of the pannus. Intraoperative findings showed the TAVR valve was covered with neointima except around the origins of the left and right coronary arteries and was firmly adhered to the surrounding tissues. As residual pannus was present in the subvalvular tissues, it was carefully removed. The explanted TAVR valve functioned well with good opening and closure. The postoperative course was uneventful. Pannus formation can result from mechanical stress. TAVR valves put significantly greater stress on the left ventricular outflow tract than surgical valves and may be more likely to cause pannus formation.

Left Ventricular Outflow Tract Obstruction in Congenital Heart Disease: The Role of Cardiovascular Computed Tomography in Surgical Decision Making.

Patients with many forms of congenital heart disease (CHD) and hypertrophic cardiomyopathy undergo surgical intervention to relieve left ventricular outflow tract obstruction (LVOTO). Cardiovascular Computed Tomography (CCT) defines the complex pathway from the ventricle to the outflow tract and can be visualized in 2D, 3D, and 4D (3D in motion) to help define the mechanism and physiologic significance of obstruction. Advanced cardiac visualization may aid in surgical planning to relieve obstruction in the left ventricular outflow tract, aortic or neo-aortic valve and the supravalvular space. CCT scanner technology has advanced to achieve submillimeter, isotropic spatial resolution, temporal resolution as low as 66 msec allowing high-resolution imaging even at the fast heart rates and small cardiac structures of pediatric patients ECG gating techniques allow radiation exposure to be targeted to a minimal portion of the cardiac cycle for anatomic imaging, and pulse modulation allows cine imaging with a fraction of radiation given during most of the cardiac cycle, thus reducing radiation dose. Scanning is performed in a single heartbeat or breath hold, minimizing the need for anesthesia or sedation, for which CHD patents are highest risk for an adverse event. Examples of visualization of complex left ventricular outflow tract obstruction in the subaortic, valvar and supravalvular space will be highlighted, illustrating the novel applications of CCT in this patient subset.

Five-year follow-up after percutaneous pulmonary valve implantation using the Venus P-valve system for patients with pulmonary regurgitation and an enlarged native right ventricular outflow tract.

BACKGROUND: Percutaneous pulmonary valve implantation (PPVI) with the self-expandable Venus P-valve system is a promising treatment for patients with pulmonary regurgitation (PR) and a native right ventricular outflow tract (RVOT). However, limited data is available regarding its midterm outcomes. This study assessed the midterm clinical and echocardiographic outcomes following Venus P-valve implantation. METHODS: From 2013 to 2018, 55 patients with moderate or severe PR after surgical RVOT repair with a transannular or RVOT patch were consecutively enrolled from six hospitals in China. Five-year clinical and echocardiographic outcomes were collected and evaluated. The primary endpoint was a freedom from all-cause mortality and reintervention. RESULTS: At 5 years, the primary endpoint was met for 96% of patients, corresponding to a freedom from all-cause mortality of 96% (95% confidence interval [CI]: 86%-99%) and freedom from reintervention of 98% (95% CI: 87%-100%). Endocarditis was reported in five patients (four patients within 1 year and one patient at 5 years) following PPVI. Transpulmonary gradient and stent orifice diameter remained stable compared to at discharge (p＞0.05). No paravalvular leak was reported while only 1 patient gradually increased to moderate PR during follow-up. Significant improvement of RV diameter and LVEF (p＜0.001) sustained over the 5-year follow-up, in consistent with remarked improved New York Heart Association(NYHA) functional class (p＜0.001). CONCLUSION: The 5-year results of the China VenusP Study demonstrated the midterm benefits of Venus P-valve implantation in the management of patients with severe PR with an enlarged native RVOT by providing sustained symptomatic and hemodynamic improvement.

Expanded polytetrafluoroethylene conduits with curved and handsewn bileaflet designs for right ventricular outflow tract reconstruction.

OBJECTIVE: This study reviewed the application of curved and bileaflet designs to pulmonary expanded polytetrafluoroethylene conduits with diameters of 10 to 16 mm and characterized this conduit on in vitro experiment, including particle image velocimetry. METHODS: All patients who received this conduit between 2010 and 2022 were evaluated. Three 16-mm conduits were tested in a circulatory simulator at different cardiac outputs (1.5-3.6 L/minute) and bending angles (130°-150°). RESULTS: Fifty consecutive patients were included. The median operative body weight was 8.4 kg (range, 2.6-12 kg); 10-, 12-, 14-, and 16-mm conduits were used in 1, 4, 6, and 39 patients, respectively. In 34 patients, the conduit was implanted in a heterotopic position. The overall survival rate was 89% at 8 years with 3 nonvalve-related deaths. There were 10 conduit replacements; 5 16-mm conduits (after 8 years) and 1 12-mm conduit (after 6 years) due to conduit stenosis, and the remaining 4 for reasons other than conduit failure. Freedom from conduit replacement was 89% and 82% at 5 and 8 years, respectively. Linear mixed-effects models with echocardiographic data implied that 16-mm conduits were durable with a peak velocity <3.5 m/second and without moderate/severe regurgitation until the patient's weight reached 25 kg. In experiments, peak transvalvular pressure gradients were 11.5 to 25.5 mm Hg, regurgitant fractions were 8.0% to 14.4%, and peak Reynolds shear stress in midsystolic phase was 29 to 318 Pa. CONCLUSIONS: Our conduits with curved and bileaflet designs have acceptable clinical durability and proven hydrodynamic profiles, which eliminate valve regurgitation and serve as a reliable bridge to subsequent conduit replacement.

Reconstruction of right ventricular outflow tract with severe calcification: lantern procedure.

Right ventricular outflow tract reconstruction is repeatedly required after the Rastelli procedure. However, standard right ventricular outflow tract reconstruction using direct anastomosis on the posterior right ventricular outflow tract wall is unfeasible in cases with severe calcification. Herein, we present a novel technique called the "lantern procedure," which can fix the prosthetic pulmonary valve without anastomosis to the calcified right ventricular outflow tract wall.

Multimodal imaging diagnosis of left ventricular outflow tract obstruction due to abnormal papillary muscle insertion.

This article reports a case of LV outflow obstruction caused by abnormalities of the anterior leaflet connection of the mitral papillary muscle, aiming to highlight the importance of combined multimodal imaging in the differential diagnosis of the etiology of LV outflow obstruction.

Transapical beating-heart septal myectomy for hypertrophic cardiomyopathy with latent obstruction.

OBJECTIVES: A novel transapical beating-heart septal myectomy (TA-BSM) procedure was performed for patients with latent obstruction through the left intercostal incision and without cardiopulmonary bypass. This study aims to demonstrate the experience of the TA-BSM procedure for patients with latent obstruction and compare outcomes to patients with resting obstruction. METHODS: We studied 120 symptomatic hypertrophic obstructive cardiomyopathy patients (33 with latent obstruction and 87 with resting obstruction) who underwent TA-BSM. Demographic profiles, echocardiogram-derived ventricular morphology and haemodynamics and clinical outcomes were analysed. RESULTS: There were no important differences in baseline clinical characteristics between patients with latent obstruction and resting obstruction, including age, symptoms, comorbidities and medical history. Patients with latent obstruction had lower basal septum thickness, higher midventricular wall thickness, smaller left atrial chamber size and more frequency of mitral subvalvular anomalies. There was no difference in early (<30 days) deaths (0/33 vs 1/87, P > 0.999) and mid-term survival between patients with latent obstruction and resting obstruction. At 6 months after surgery, 31 (93.9%) patients with latent obstruction and 80 (92.0%) with resting obstruction achieved optimal procedural success, which was defined as a maximal gradient (after provocation) <30 mmHg and mitral regurgitation ≤ grade 1+ without mortality. Maximal left ventricular outflow tract gradient, basal septum thickness, midventricular wall thickness, mitral regurgitation grade and left atrial chamber size were significantly decreased after TA-BSM. In the follow-up, the New York Heart Association class was significantly improved following surgery. CONCLUSIONS: TA-BSM preserved favourable gold-standard guideline desired outcomes through real-time echocardiographic-guided resection. Equipoise of outcomes for this procedure regardless of degree of resting left ventricular outflow tract gradients supports operative management with this approach in symptomatic patients with latent obstruction.

Right ventricular outflow tract obstruction associated with neointimal tissue accumulation and distortion of the Harmony TPV25 stent frame: Potential mechanisms and treatment.

BACKGROUND: The Harmony TPV25 transcatheter pulmonary valve (Medtronic Inc.) is constructed with a self-expanding stent frame comprising six zigged nitinol wires sewn together and covered with knitted polyester fabric, with flared inflow and outflow ends and a porcine pericardial valve sutured to the central portion of the device. It was approved for treatment of pulmonary regurgitation after prior right ventricular outflow tract repair in 2021. Early outcomes of this procedure have been excellent, but little is known about valve durability or ultimate mechanisms of dysfunction. METHODS: We collected data on patients who underwent reintervention for TPV25 dysfunction and described findings related to distortion of the stent frame and tissue accumulation. RESULTS: We describe six patients who underwent valve-in-valve implant for TPV25 obstruction (peak catheterization gradient peak 28-73 mmHg) 10-28 months after implant. In all cases, there was tissue accumulation within the inflow and valve-housing segments of the device and deformation of the self-expanding valve frame characterized by variable circumferential narrowing at the junction between the valve housing and the inflow and outflow portions of the device, with additional geometric changes in all segments. All six patients underwent valve-in-valve implant that results in a final peak gradient ≤10 mmHg and no regurgitation. DISCUSSION: The occurrence of short-term Harmony TPV25 dysfunction in multiple patients with a similar appearance of frame distortion and tissue accumulation within the inflow and valve housing portions of the device suggests that this may be an important failure mechanism for this valve. Potential causes of the observed findings are discussed. It is possible to treat this mechanism of TPV25 dysfunction with valve-in-valve implant using balloon expandable transcatheter valves.

Preemptive alcohol septal ablation prior to transcatheter mitral valve replacement.

BACKGROUND: Alcohol septal ablation (ASA) has been shown to increase the neo-left ventricular outflow tract (LVOT) area before transcatheter mitral valve replacement (TMVR) but there is little literature on its success and use with dedicated devices. AIMS: To describe our experience with preemptive ASA to increase the predicted neo-LVOT area and its utility with both dedicated TMVR devices and balloon-expandable valves. METHODS: All patients who underwent ASA for TMVR candidacy in our center between May 2018 and October 2022 and had computed tomography (CT) scans done before and after ASA were included. Each CT was assessed for the minimum predicted neo-LVOT area at end-systole, using a virtual valve of the desired TMVR device for each patient. The primary outcome was an increase in the predicted neo-LVOT area after ASA that was deemed sufficient for safe implantation of the desired TMVR device. The secondary outcome was the absence of acute LVOT obstruction after TMVR. RESULTS: A total of 12 patients underwent ASA and all but 1 (n = 11, 91.6%) achieved the primary outcome of having sufficient predicted neo-LVOT area to proceed with TMVR. The mean increase in neo-LVOT area after ASA was 126 ± 64 mm2 (median 119.5, interquartile range: 65.0-163.5 mm2 ). Two patients (16.7%) required a permanent pacemaker after ASA. Nine patients went on and underwent TMVR with their respective devices and none had LVOT obstruction after the procedure. Among the remaining three patients, one had insufficient neo-LVOT clearance after ASA, one had unrelated mortality before TMVR, and one had advanced heart failure before TMVR. CONCLUSION: In appropriately selected patients and at centers experienced with ASA, preemptive ASA can achieve sufficient neo-LVOT clearance for TMVR with a variety of devices in approximately 90% of patients.

A novel method of prosthetic leaflet modification to enable transcatheter mitral valve-in-valve replacement.

Left ventricular outflow tract (LVOT) obstruction from the displaced prosthetic anterior mitral leaflet is a life-threatening complication that can occur during valve-in-valve (ViV) transcatheter mitral valve replacement (TMVR). Laceration of the anterior mitral leaflet to prevent outflow obstruction is a well-established transcatheter technique to mitigate the risk of LVOT obstruction in high-risk anatomies. In this report, we present a novel transseptal technique of prosthetic leaflet modification to prevent LVOT obstruction during ViV TMVR.

Haemodynamic effects of acute intravenous landiolol in Takotsubo cardiomyopathy with dynamic left ventricular outflow tract obstruction.

Takotsubo cardiomyopathy (TCM) leads to serious left ventricular outflow tract (LVOT) obstruction with cardiogenic shock in 6%-20% of cases. The onset of LVOT obstruction, coupled with mitral regurgitation resulting from systolic anterior motion of mitral valve leaflets, can lead to haemodynamic instability in addition to severely impaired systolic function. We describe three patients who experienced chest discomfort following emotional stress. These patients displayed pronounced abnormalities on ECGs, insignificant obstructive coronary disease and haemodynamic instability due to LVOT obstruction. The infusion of landiolol, a short-acting beta blocker, was effective in releasing the gradient. Dynamic outflow obstruction is the major predictor of haemodynamic collapse. We suggested that an early identification of this complication in hypotensive patients with suspected TCM could be of utmost importance to optimise the therapeutic approach in the acute setting.

Accessory mitral valve tissue: a differential diagnosis of an obstructive mass on the left ventricular outflow tract.

Accessory mitral valve tissue is a rare congenital cardiac anomaly that is typically discovered incidentally during echocardiographic evaluation prompted by an asymptomatic murmur. This pathology has characteristic echocardiographic elements and is usually associated with other CHD. The decision to perform surgical resection depends on factors such as the degree of obstruction, presence of symptoms, presence of other CHDs, and risk of thrombosis. The researchers hereby present a case of an asymptomatic paediatric patient with accessory mitral valve tissue that produced left ventricular outflow tract obstruction.