Benchtop Flow Stasis Quantification: In Vitro Methods and In Vivo Possibilities.

PURPOSE: Neo-sinus flow stasis has ben correlated with transcatheter heart valve (THV) thrombosis severity and occurrence. Standard benchtop flow field quantification techniques require optical access or modified prosthesis models that may not reflect the true nature of the original valve. En face and fluoroscopic videodensitometry enable visualization of washout in regions otherwise unviewable. METHODS: This study compares two in vitro methods of assessing flow stasis in scenarios with insufficient optical access for traditional techniques such as particle image velocimetry (PIV). A series of seven paired experiments were conducted using a previously described laser-enhanced video densitometry (LEVD) and fluoroscopic video densitometry (FVD). Both sets of experiments were analyzed to calculate washout time as a measure of flow stasis. A novel flow stasis measure termed contrast attenuation ratio (CAR) is proposed as a viable single measure of flow stasis obtainable from only a small number of cardiac cycles of in vitro or in vivo fluoroscopic data. Retrospective fluoroscopic datasets (n = 72) were analyzed to assess the feasibility of obtaining this metric from routine clinical practice and its ability to stratify results. RESULTS: Neo-sinus flow stasis calculated from in vitro fluoroscopy was well correlated with LEVD (r2 = 0.77, p = 0.009). The newly proposed CAR metric showed good agreement with the commonly used "washout time" measure of flow stasis (r2 = 0.91, p < 0.001) while allowing for assessment with incomplete or truncated data. As a proof of concept, CAR was measured in 72 consecutive retrospective fluoroscopic datasets. CAR averaged 10.6 ± 4.6% with a range of 1.5-20.3% in these patients. CONCLUSIONS: This study demonstrates two in vitro methods that can be used to assess relative flow stasis in otherwise optically inaccessible regions surrounding cardiac or vascular implants. In addition, the fluoroscopic benchtop technique was used to validate a metric that allows for extension to routine clinical fluoroscopy. This contrast attenuation ratio (CAR) metric was found to be both accurate and clinically obtainable, and potentially offers a new method for valve thrombosis risk stratification.

Pathological evaluation of predictors for delayed endothelial coverage after currently available drug-eluting stent implantation in coronary arteries: Impact of lesions with acute and chronic coronary syndromes.

BACKGROUND: The optimal duration of dual antiplatelet therapy after currently available drug-eluting stent (DES) implantation to prevent stent thrombosis (ST) remains controversial. Delayed healing is frequently identified as a leading cause of ST in the early phase. However, a thorough pathological investigation into strut coverage after currently available DES implantation is lacking-a gap addressed in the current study. METHODS: From our autopsy registry of 199 stented lesions, 4,713 struts from 66 currently available DES-stented lesions with an implant duration ≤370 days were histologically evaluated. Endothelial coverage was defined as the presence of luminal endothelial cells overlying struts and an underlying smooth muscle cell layer. The stented lesions were classified into acute coronary syndrome (ACS) (n = 40) and chronic coronary syndrome (CCS) (n = 26) groups and were compared. Endothelial coverage predictors were identified through logistic analysis. RESULTS: Although ACS and CCS lesions presented comparable clinical characteristics, including age, sex, and cause of death, the latter exhibited a significantly higher prevalence of chronic kidney disease and hemodialysis than the former (33.3% vs. 65.2%; P = .02, 7.7% vs. 30.4%; P = .02). The poststent implant median duration was significantly shorter in ACS lesions than in CCS lesions (13 [IQR 5-26 days] vs. 40 [IQR 16-233 days]; P < .01). The endothelial coverage percentage was 3.5% at 30 days and 27.7% at 90 days after currently available DES implantation. Multivariable logistic regression analysis implicated implant duration of ≤90 days (odds ratio [OR], 0.009; 95% confidence interval [CI], 0.006-0.012; P < .01), superficial calcification (OR, 0.11; 95% CI, 0.07-0.17; P < .01), ACS culprit site (OR, 0.29; 95% CI, 0.09-0.94; P = .039), and circumferentially durable polymer-coated DES (OR, 0.32; 95% CI, 0.24-0.41; P < .01) as delayed endothelial coverage predictors. CONCLUSIONS: Endothelial coverage was limited at 90 days after currently available DES implantation, and the ACS culprit site and circumferentially durable polymer-coated DES were identified as independent predictors of delayed endothelial coverage. Our findings suggest the importance of underlying plaque morphology and stent technology for vessel healing after such implantation.

Patient-specific analysis of bicuspid aortic valve hemodynamics using a fully coupled fluid-structure interaction model.

Bicuspid aortic valve (BAV), the most common congenital heart disease, is prone to develop significant valvular dysfunction and aortic wall abnormalities such as ascending aortic aneurysm. Growing evidence has suggested that abnormal BAV hemodynamics could contribute to disease progression. In order to investigate BAV hemodynamics, we performed 3D patient-specific fluid-structure interaction (FSI) simulations with fully coupled blood flow dynamics and valve motion throughout the cardiac cycle. Results showed that the hemodynamics during systole can be characterized by a systolic jet and two counter-rotating recirculation vortices. At peak systole, the jet was usually eccentric, with asymmetric recirculation vortices and helical flow motion in the ascending aorta. The flow structure at peak systole was quantified using the vorticity, flow rate reversal ratio and local normalized helicity (LNH) at four locations from the aortic root to the ascending aorta. The systolic jet was evaluated with the peak velocity, normalized flow displacement, and jet angle. It was found that peak velocity and normalized flow displacement (rather than jet angle) gave a strong correlation with the vorticity and LNH in the ascending aorta, which suggests that these two metrics could be used for clinical noninvasive evaluation of abnormal blood flow patterns in BAV patients.

Vericiguat and transcatheter edge-to-edge mitral valve repair for combined post- and pre-capillary pulmonary hypertension due to left ventricular low ejection fraction and functional mitral regurgitation.

A 66-year-old female was diagnosed with combined post- and pre-capillary pulmonary hypertension due to heart failure with reduced ejection fraction (47 %) and functional mitral regurgitation [mean pulmonary arterial wedge pressure: 27 mmHg; pulmonary arterial pressure: 91/30 (56) mmHg; pulmonary vascular resistance: 12.9 Wood units; and cardiac index: 1.77 L/min/m2]. Following treatment with vericiguat (a novel oral soluble guanylate cyclase stimulator), hemodynamics improved [mean pulmonary arterial wedge pressure: 27 mmHg; pulmonary arterial pressure: 54/26 (35) mmHg; pulmonary vascular resistance: 2.2 Wood units; and cardiac index: 2.80 L/min/m2]. Therefore, transcatheter edge-to-edge repair for functional mitral regurgitation was performed. One month later, further improvement in hemodynamics was confirmed. Learning objective: Vericiguat (a novel oral soluble guanylate cyclase stimulator) and transcatheter edge-to-edge mitral valve repair may improve combined post- and pre-capillary pulmonary hypertension due to low ejection fraction of the left ventricle and functional mitral regurgitation.

Feasibility and Outcome of Transjugular Intracardiac Echocardiography-Guided Transcatheter Aortic Valve Replacement.

Background: There are limited data on the impact of intracardiac echocardiography (ICE)-guided transcatheter aortic valve replacement (TAVR) on the new permanent pacemaker implantation (PPMI) rate. Objectives: This study investigated the feasibility and outcome of transjugular ICE (TJ-ICE) -guided TAVR, by visualizing the relationship between the membranous septum (MS) and the transcatheter aortic valve (TAV). Methods: Among patients with severe aortic stenosis who underwent TAVR between February 2017 and June 2020, this study enrolled a total of 163 patients with TJ-ICE-guided TAVR. MS length was measured by ICE. The primary endpoint of this study was the incidence of new PPMI at 30 days. Results: The mean age of the patients in this study was 84.9 ± 4.6 years, and 71.2% of the patients were female. Device success was 96.3% with TJ-ICE guidance. A TJ-ICE-related complication occurred in 1 case (0.6%). The median length of the MS was 5.8 mm (IQR: 5.0-6.9 mm). Excellent intraobserver (intraclass correlation coefficient [ICC]: 0.94; 95% CI:0.79-0.98; P < 0.001) and interobserver (ICC: 0.93; 95% CI: -0.05 to 0.98; P < 0.001) agreements were shown. The new PPMI rate was 6.7% at 30 days without a significant difference between balloon-expandable valves and self-expandable valves (3.4% vs 8.7%; P = 0.226). Patients with a TAV implantation depth less than MS length had a significantly lower incidence of new PPMI compared with patients with a TAV implantation depth greater than MS length (2.1% vs 13.4%; P = 0.005), regardless of baseline right bundle branch block presence (6.7% vs 66.7%; P = 0.004) or absence (1.2% vs 8.2%; P = 0.041). Conclusions: TJ-ICE-guided TAVR demonstrated remarkable feasibility and safety. The TJ-ICE-guided final TAV position had a significant impact on the new PPMI rate. (Tokai Valve Registry; UMIN000036671).

Incremental Value of Global Longitudinal Strain for Confirming Heart Failure-Related Symptoms in Severe Aortic Stenosis.

The indications or timing of aortic valve replacement for symptomatic aortic stenosis (AS) are based on a patient's life expectancy and symptoms. However, clinical decision-making may be difficult because symptoms are subjective and cannot be quantitatively assessed and confirmed. This study aimed to evaluate the association between heart failure (HF)-related symptoms and cardiac hemodynamic left ventricular deformations in patients with severe AS using transthoracic echocardiographic assessments of left ventricular global longitudinal strain (LV-GLS). The medical records of patients hospitalized for AS between February 2017 and September 2019 were retrospectively screened. Independent cardiologists analyzed the transthoracic echocardiographic images of a digital echocardiography database. The cohort comprised 177 hospitalized patients with severe AS and no history of HF. The subgroup with HF-related symptoms included 87 patients, whereas that without HF-related symptoms included 90 patients. In 145 patients without atrial fibrillation, the left atrial volume index (LAVI) and LV-GLS were significantly associated with HF-related symptoms (odds ratio 1.033, 95% confidence interval 1.008 to 1.059, p = 0.011 and odds ratio 1.224, 95% confidence interval 1.118 to 1.340, p <0.0001, respectively). Moreover, the combination of brain natriuretic peptide level, LAVI, and LV-GLS showed better diagnostic accuracy than the combination of brain natriuretic peptide level and LAVI (p = 0.005). However, there were no such tendencies in 32 patients with atrial fibrillation. The HF-related symptoms in patients with severe AS were strongly linked to LV-GLS. LV-GLS showed incremental value for confirming HF-related symptoms.

Mechanisms and implications of mitral regurgitation in patients with severe aortic stenosis who received transcatheter aortic valve replacement.

INTRODUCTION: This study aimed to investigate the mechanisms and clinical implications of mitral regurgitation (MR) in patients with severe aortic stenosis (AS) who received transcatheter aortic valve replacement (TAVR). METHODS: We conducted retrospective echocardiographic analyses at baseline and 6 months after TAVR in 140 patients with symptomatic AS (85 ± 5 years) who underwent TAVR. We defined significant MR as ≥ moderate based on evaluation of transthoracic echocardiography (TTE). RESULTS: There were 48 patients (34%) with preexisting MR at the baseline. Among measured TTE parameters, end-systolic wall stress (ESWS), mitral annulus area, and mitral valve thickening index were independent factors associated with preexisting MR (odds ratio [OR]: 1.013, 95% confidence interval [CI]: 1.005-1.021; OR: 1.740, 95% CI: 1.314-2.376; OR: 2.306, 95% CI: 1.426-3.848; respectively). Six months after TAVR, there were 34 patients with post-existing MR, A history of atrial fibrillation and ESWS after TAVR were independent factors (OR: 3.013, 95% CI: 1.208-7.556; OR: 1.013, 95% CI: 1.000-1.023; respectively). The Kaplan-Meier plot indicated that preexisting MR was a risk factor for heart failure-related events within 1 year of discharge after TAVR (p = .012). CONCLUSIONS: In patients who underwent TAVR for severe AS, preexisting MR was associated with having a thickened mitral valve and large mitral annulus size induced by high ESWS. These patients may have worse prognosis after TAVR and should be closely monitored in the long term.

Coronary Obstruction From TAVR in Native Aortic Stenosis: Development and Validation of Multivariate Prediction Model.

BACKGROUND: Transcatheter aortic valve replacement (TAVR)-related coronary artery obstruction prediction remains unsatisfactory despite high mortality and novel preventive therapies. OBJECTIVES: This study sought to develop a predictive model for TAVR-related coronary obstruction in native aortic stenosis. METHODS: Preprocedure computed tomography and fluoroscopy images of patients in whom TAVR caused coronary artery obstruction were collected. Central laboratories made measurements, which were compared with unobstructed patients from a single-center database. A multivariate model was developed and validated against a 1:1 propensity-matched subselection of the unobstructed cohort. RESULTS: Sixty patients with angiographically confirmed coronary obstruction and 1,381 without obstruction were included. In-hospital death was higher in the obstruction cohort (26.7% vs 0.7%; P < 0.001). Annular area and perimeter, coronary height, sinus width, and sinotubular junction height and width were all significantly smaller in the obstructed cohort. Obstruction was most common on the left side (78.3%) and at the level of the coronary artery ostium (92.1%). Coronary artery height and sinus width, but not annulus area, were significant risk factors for obstruction by logistic regression but performed poorly in predicting obstruction. The new multivariate model (coronary obstruction IF cusp height > coronary height, AND virtual valve-to-coronary distance ≤4 mm OR culprit leaflet calcium volume >600 mm3) performed well, with an area under the curve of 0.93 (sensitivity = 0.93, specificity = 0.84) for the left coronary artery and 0.94 (sensitivity = 0.92, specificity = 0.96) for the right. CONCLUSIONS: A novel computed tomography-based multivariate prediction model that can be implemented routinely in real-world practice predicted coronary artery obstruction from TAVR in native aortic stenosis.

Short-term Outcomes of Urgent Transcatheter Aortic Valve Replacement in Symptomatic Aortic Stenosis That Requires Emergency Hospital Admission.

Objective This study retrospectively compared the outcomes of emergently admitted patients with aortic stenosis (AS) with or without urgent transcatheter aortic valve replacement (TAVR). Methods Patients hospitalized between February 2015 and December 2019 for symptomatic AS were retrospectively analyzed by comparing the received conservative management [continued medical therapy with or without elective surgical transcatheter replacement (SAVR) or TAVR scheduled after the index hospitalization] and urgent TAVR (TAVR during the index hospitalization). Results The cohort comprised 114 patients with symptomatic AS who required emergency admission. Urgent TAVR was performed for 37 patients, while conservative management was provided for 77 patients, including 1 who received urgent SAVR. Urgent TAVR was more likely to be performed in patients with a history of hospitalization for heart failure, high New York Heart Association class scores, a lower clinical frailty scale at admission, and a high aortic valve peak velocity (p=0.01, p<0.001, p<0.01 and p=0.02, respectively). Kaplan-Meier analyses with log-rank test revealed favorable outcomes of urgent TAVR in all-cause mortality and cardiovascular events within 60 days of admission (p<0.01, p<0.01, respectively). Conclusion Urgent TAVR had better short-term outcomes in patients with symptomatic AS who required emergency hospital admission than conservative management. When considering urgent TAVR, patients with typical heart failure symptoms due to AS with a history of heart failure hospitalization and relatively little frailty can be selected.

First Application of the LAMPOON Procedure to a Surgical Mitral Bioprosthesis.

A cardiogenic shock patient with a history of a surgical mitral valve replacement presented to the hospital with critical mitral stenosis with thickening of prosthetic valve leaflets and thrombus in left atrial appendage. We considered TMVR inside of the degenerated bioprosthetic valve. However, there were two concerns during TMVR based on multimodality imaging assessment: 1) LVOT obstruction due to the surgical bioprosthetic leaflet, 2) stroke due to left atrial appendage thrombus. We performed TMVR with LAMPOON (laceration of the anterior leaflet of the surgical valve to prevent left ventricular outflow tract obstruction) for the bioprosthesis using cerebral protection. While the LAMPOON procedure has developed to prevent LVOT obstruction by the native anterior mitral leaflet during transcatheter mitral valve-in-ring or valve-in-mitral annular calcification, this is the first case that illustrates its use for mitral valve-in-valve replacement.

Pathological Analysis of Medial and Intimal Calcification in Lower Extremity Artery Disease: Impact of Hemodialysis.

Background: The prevalence and degree of lower extremity artery disease in hemodialysis (HD) patients is higher than in the general population. However, the pathological features have not yet been evaluated. Objectives: The aim of the study was: 1) to compare lesion characteristics of lower extremity artery disease in HD vs non-HD patients; and 2) to determine factors associated with severe medial calcification. Methods: Seventy-seven lower limb arteries were assessed from 36 patients (median age 77 years; 23 men; 21 HD and 15 non-HD) who underwent autopsy or lower limb amputation. Arteries were serially cut at 3- to 4-mm intervals creating 2,319 histological sections. Morphometric analysis and calcification measurements were performed using ZEN software. Calcification with a circumferential angle (arc) ≥180° was defined as severe calcification. Multivariable logistic regression was used to identify risk factors for severe medial calcification. Results: The degree of the medial calcification arc was significantly higher in the HD group compared to the non-HD group (P < 0.0001). In the multivariable analysis, HD was associated with severe medial calcification in below-the-knee lesions (OR: 17.1; P = 0.02). The degree of intimal calcification in above-the-knee lesions was also significantly higher in HD patients with a higher prevalence of advanced atherosclerotic plaque (P = 0.02). The prevalence of severe bone formation was more common in the HD patients (P = 0.01). Conclusions: Hemodialysis patients demonstrated a higher degree of medial and intimal calcification compared with non-HD patients. The difference was more prominent in the medial calcification of below-the-knee lesions.

Impact of Periprocedural Pulmonary Hypertension on Outcomes After Transcatheter Aortic Valve Replacement.

BACKGROUND: There are limited data on the prognostic impact of periprocedural pulmonary hypertension (PH) after transcatheter aortic valve replacement (TAVR). OBJECTIVES: The aim of this study was to investigate the prognostic impact of normalized, new-onset, and residual PH after TAVR. METHODS: The OCEAN-TAVI (Optimized Transcatheter Valvular Intervention-Transcatheter Aortic Valve Implantation) registry is an ongoing, multicenter Japanese registry that includes 2,588 patients who underwent TAVR. Patients were classified into 4 groups according to periprocedural systolic pulmonary artery pressure by echocardiography: no PH before and after TAVR (no PH), PH before but not after TAVR (normalized PH), PH after but not before TAVR (new-onset PH), and PH before and after TAVR (residual PH). A systolic pulmonary artery pressure cutoff of >36 mm Hg was applied for PH. The primary endpoint was all-cause mortality at 2 years. Logistic regression analysis was used to identify clinical predictors of residual and new-onset PH. RESULTS: In total, 1,872 patients were divided into 4 groups: 1,027 (54.9%) in the no PH group, 257 (13.7%) in the normalized PH group, 280 (15.0%) in the new-onset PH group, and 308 (16.5%) in the residual PH group. There was a significant difference in all-cause mortality among the 4 groups at 2 years (11.0%, 12.8%, 18.6%, and 24.7%, respectively; P < 0.01). Among 565 patients who had preprocedural PH, 257 (45.5%) experienced normalization of PH, with mortality comparable with that in the no PH group. In multivariable logistic regression analysis, predictors of residual PH after TAVR were atrial fibrillation and baseline tricuspid regurgitation moderate or greater, whereas prosthesis-patient mismatch was a predictor of new-onset PH. CONCLUSIONS: Risk stratification on the basis of post-TAVR PH status can identify patients at increased mortality after TAVR. Prosthesis-patient mismatch was identified as a novel predictor of new-onset PH. (Optimized Transcatheter Valvular Intervention-Transcatheter Aortic Valve Implantation [OCEAN-TAVI]; UMIN000020423).

The role of flow stasis in transcatheter aortic valve leaflet thrombosis.

OBJECTIVE: With the recent expanded indication for transcatheter aortic valve replacement to low-risk surgical patients, thrombus formation in the neosinus is of particular interest due to concerns of reduced leaflet motion and long-term transcatheter heart valve durability. Although flow stasis likely plays a role, a direct connection between neosinus flow stasis and thrombus severity is yet to be established. METHODS: Patients (n = 23) were selected to minimize potential confounding factors related to thrombus formation. Patient-specific 3-dimensional reconstructed in vitro models were created to replicate in vivo anatomy and valve deployment using the patient-specific cardiac output and idealized coronary flows. Dye was injected into each neosinus to quantify washout time as a measure of flow stasis. RESULTS: Flow stasis (washout time) showed a significant, positive correlation with thrombus volume in the neosinus (rho = 0.621, P < .0001). Neither thrombus volume nor washout time was significantly different in the left, right, and noncoronary neosinuses (P ≥ .54). CONCLUSIONS: This is the first patient-specific study correlating flow stasis with thrombus volume in the neosinus post-transcatheter aortic valve replacement across multiple valve types and sizes. Neosinus-specific factors create hemodynamic and thrombotic variability within individual patients. Measurement of neosinus flow stasis may guide strategies to improve outcomes in transcatheter aortic valve replacement.

Balloon-Augmented Leaflet Modification With Bioprosthetic or Native Aortic Scallop Intentional Laceration to Prevent Iatrogenic Coronary Artery Obstruction and Laceration of the Anterior Mitral Leaflet to Prevent Outflow Obstruction: Benchtop Validation and First In-Man Experience.

BACKGROUND: Bioprosthetic or native aortic scallop intentional laceration to prevent iatrogenic coronary artery obstruction (BASILICA) and laceration of the anterior mitral leaflet to prevent outflow obstruction (LAMPOON) reduce the risk of coronary and left ventricular outflow obstruction obstruction during transcatheter aortic valve replacement and transcatheter mitral valve replacement. Despite successful laceration, BASILICA or LAMPOON may fail to prevent obstruction caused by inadequate leaflet splay in patients having challenging anatomy such as very small valve-to-coronary distance, diffusely calcified, rigid leaflets, or undergoing transcatheter aortic valve replacement inside existing transcatheter aortic valve replacement. We describe a novel technique of balloon-augmented (BA) leaflet laceration to enhance leaflet splay. METHODS: We measured the incremental leaflet splay from BA-BASILICA in vitro. From November 2019 to March 2021, 16 patients underwent BA-BASILICA and 4 BA-LAMPOON at 3 centers. RESULTS: BA-BASILICA increased benchtop leaflet tip splay 17%, maximum splay angle 30%, and splay area 23%, resulting in a more rounded apex and larger effective area. Sixteen patients at risk for inadequate BASILICA leaflet splay, including 4 transcatheter aortic valve replacement inside existing transcatheter aortic valve replacement, underwent BA-BASILICA. All had successful leaflet laceration. One had coronary obstruction requiring immediate orthotopic stenting. Two underwent elective orthotopic coronary stenting through the transcatheter valve cells for leaflet prolapse without coronary ischemia. There were no deaths during the procedure or at 30 days. Four patients at risk for inadequate anterior mitral leaflet splay underwent BA-LAMPOON. All had successful target leaflet laceration without left ventricular outflow obstruction obstruction or procedural death. One died within 30 days. CONCLUSIONS: BA leaflet laceration enhances leaflet splay in vitro and may allow transcatheter aortic valve replacement and transcatheter mitral valve replacement in patients otherwise ineligible for traditional BASILICA or LAMPOON due to challenging anatomy. Graphic Abstract: A graphic abstract is available for this article.

The Art of SAPIEN 3 Transcatheter Mitral Valve Replacement in Valve-in-Ring and Valve-in-Mitral-Annular-Calcification Procedures.

The SAPIEN 3 is the only transcatheter heart valve commercially available for compassionate transcatheter mitral valve replacement in patients with previous mitral surgical rings and mitral annular calcification (valve in ring [VIR] and valve in mitral annular calcification [VIM]). Reported outcomes have been inconsistent or poor. The review provides an overview of the authors' approach to achieve largely consistent results despite the intrinsic limitations of SAPIEN 3 VIM and VIR. The approach includes bedside modifications of the valve implant, the delivery system, and of the cardiac substrate itself. Until purpose-built devices are readily available, VIR and VIM procedures will require aggressive multidisciplinary cooperation, meticulous planning and execution, and postprocedure management by experienced, high-volume operators.

Outflow graft obstruction after left ventricular assist device implantation: a retrospective, single-centre case series.

AIMS: Outflow graft obstruction is a poorly described complication following left ventricular assist device (LVAD) surgery. We sought to define the incidence of LVAD outflow graft obstruction and assess clinical outcomes with a percutaneous treatment strategy. METHODS AND RESULTS: From January 2012 to October 2020, 322 patients with LVAD were managed at our institution. Patients with LVAD outflow graft obstruction were identified by cardiac computed tomography with angiography and invasive haemodynamic assessment and were subsequently treated with percutaneous intervention. Poisson regression was used to analyse time-dependent differences in the incidence of LVAD outflow graft obstruction. Kaplan-Meier analysis was used to estimate survival. Twenty patients (6.2%) developed haemodynamically significant LVAD outflow graft obstruction at a rate of 0.03 events per patient-year. Outflow graft obstruction presented a median of 33 (26-49) months after surgery. Patients presented with low estimated LVAD pump flow (95%), heart failure (90%), or both (85%), and 59% developed cardiogenic shock prior to intervention. The most common aetiology identified by cardiac computed tomography with angiography was external compression of the outflow graft (78%). On presentation, the median peak gradient in the outflow graft was 78 (64-100) mmHg. Outflow graft stenting was 100% successful with no in-hospital mortality, and it reduced the peak outflow graft gradient to 10 (2-17) mmHg (P < 0.001). Outflow graft stenting was durable with two patients (10%) requiring a repeat procedure over a median follow-up of 13 (7-20) months and did not impact survival. CONCLUSIONS: Left ventricular assist device outflow graft obstruction is a relatively common and underappreciated cause of recurrent heart failure and LVAD dysfunction. Outflow graft stenting can be achieved with low morbidity and provides a long-term solution to this complication.

Tip-to-Base LAMPOON for Transcatheter Mitral Valve Replacement With a Protected Mitral Annulus.

OBJECTIVES: The purpose of this study was to evaluate tip-to-base intentional laceration of the anterior mitral leaflet to prevent left ventricular outflow tract obstruction (LAMPOON) in patients undergoing transcatheter mitral valve replacement (TMVR) in annuloplasty rings or surgical mitral valves. BACKGROUND: LAMPOON is an effective adjunct to TMVR that prevents left ventricular outflow tract obstruction (LVOTO). Laceration is typically performed from the base to the tip of the anterior mitral leaflet. A modified laceration technique from leaflet tip to base may be effective in patients with a prosthesis that protects the aortomitral curtain. METHODS: This is a multicenter, 21-patient, consecutive retrospective observational cohort. Patients underwent tip-to-base LAMPOON to prevent LVOTO and leaflet overhang, or therapeutically to lacerate a long anterior mitral leaflet risking or causing LVOTO. Outcomes were compared with findings from patients in the LAMPOON investigational device exemption trial with a prior mitral annuloplasty. RESULTS: Twenty-one patients with a annuloplasty or valve prosthesis-protected mitral annulus underwent tip-to-base LAMPOON (19 preventive, 2 rescue). Leaflet laceration was successful in all and successfully prevented or treated LVOTO in all patients. No patients had significant LVOTO upon discharge. There were 2 cases of unintentional aortic valve injury (1 patient underwent emergency transcatheter aortic valve replacement and 1 patient underwent urgent surgical aortic valve replacement). In both cases, the patients had a supra-annular ring annuloplasty, and the retrograde aortic guiding catheter failed to insulate the guidewire lacerating surface from the aortic root. All patients survived to 30 days. Compared with classic retrograde LAMPOON, there was a trend toward shorter procedure time. CONCLUSIONS: Tip-to-base laceration is a simple, effective, and safe LAMPOON variant applicable to patients with an appropriately positioned mitral annular ring or bioprosthetic valve. Operators should take care to insulate the lacerating surface from adjacent structures.

LAMPOON techniques to prevent or manage left ventricular outflow tract obstruction in transcatheter mitral valve replacement.

Transcatheter mitral valve replacement (TMVR) is a therapeutic option for patients with severe mitral disease who are deemed inoperable due to their overall surgical risk. The close relationships between the left ventricular outflow tract (LVOT) and the anterior mitral valve leaflet can lead to LVOT obstruction, a common complication with high mortality. Predicting and preventing LVOT obstruction is therefore essential, prior to TMVR. Laceration of the Anterior Mitral leaflet to Prevent Outflow ObtructioN (LAMPOON) is a transcatheter electrosurgical technique to split the anterior mitral valve leaflet immediately prior to TMVR. The technique has been studied in a prospective clinical trial and has evolved with many iterations for specific anatomies. In this review, we discuss the different LAMPOON techniques to prevent and treat LVOT obstruction.