Mechanical Properties of the Myocardium Post-Alcohol Ablation in Transcatheter Mitral Valve Implantation.

Transcatheter mitral valve replacement (TMVR) is an option for patients at high risk for mitral valve replacement or repair via sternotomy or left thoracotomy approach. TMVR carries up to 22% risk of left ventricular outflow tract (LVOT) obstruction. Severe LVOT obstruction can have devastating hemodynamic and clinical consequences. We previously presented a novel technique to prevent LVOT obstruction during transapical retrograde mitral valve replacement, by penetrating and ballooning the anterior mitral leaflet (AML), resulting in creation of a "hole" and posterior translocation of AML, then deploying the valve. Three patients underwent TMVR at Saint Louis University for severe mitral regurgitation after being deemed too high risk for surgery, and not candidates for a Mitra-clip procedure. These patients were deemed to be at risk for LVOT obstruction based on the preprocedural evaluation. Via transapical approach, a needle was advanced "through," perforating the AML and wire was placed in the left atrium. Over the wire, an 20-mm valvuloplasty balloon was positioned "within" the anterior leaflet and inflated leading to translocation of the AMVL. Then the valve was deployed. This novel technique has been performed on three patients at our institution. Sapien S3 transcatheter valves were used in all three patients, with 100% procedural success rate. Intraoperative TEE demonstrated no significant LVOT obstruction, cardiopulmonary bypass time was 42-44 min. The balloon assisted translocation of the mitral anterior leaflet to prevent left ventricular outflow obstruction technique described here may offer the option of transcatheter mitral valve implantation in patients at high risk of LVOT obstruction. A variation of this technique to allow application in cases with transseptal approach is under investigation.

Patients undergoing transcatheter mitral valve replacement (TMVR) for mitral valve disease caused by severe mitral annular calcification are at risk of left ventricular outflow obstruction. Preemptive alcohol septal ablation (ASA) can potentially mitigate the risk of this complication and is well established in patients with hypertrophic obstructive cardiomyopathy (HCM). This retrospective study compared procedural characteristics and outcomes in patients who underwent ASA for TMVR vs HCM. In total, 102 patients were included, 22 in the TMVR group and 80 in the HCM group. Echocardiography demonstrated increased septal wall thickness in the HCM group (19​±​3.1​mm vs 12.7​±​2.0​mm; P​<​.001). The mean volume of ethanol injected was higher in the HCM group (1.4​±​0.49​mL vs 0.8​±​0.2​mL; P​<​.001). The average neo-left ventricular outflow tract area increased significantly after ASA in the patients undergoing TMVR (135​±​89​mm2 vs 233​±​111​mm2; P​<​.001). Six patients in the TMVR group did not achieve an adequate increase in the neo-left ventricular outflow tract area and required further procedures after ASA. The incidence of post-ASA complete heart block requiring a permanent pacemaker tended to be higher in the TMVR group (35% vs 21%; P​=​.195). No patients in either group had ventricular arrhythmia or stroke. Major bleeding complications were 4% in the HCM group and 0 in the TMVR group. The 30-day mortality was 4% in the HCM group and 0 in the TMVR group; however, 1 patient died at 37​days in the TMVR group, presumably from late heart block. Preemptive ASA in patients undergoing TMVR demonstrated safety and short-term clinical outcomes similar to patients with HCM.

Alcohol Septal Ablation to Prevent Left Ventricular Outflow Tract Obstruction During Transcatheter Mitral Valve Replacement: First-in-Man Study

To evaluate the outcomes of the early experience of percutaneous alcohol septal ablation in patients with severe left ventricular outflow tract (LVOT) obstruction post transcatheter mitral valve replacement (TMVR). Severe LVOT obstruction with hemodynamic compromise is a complication of TMVR associated with high mortality. Percutaneous alcohol septal ablation has recently been described as a therapeutic option in this setting. Multicenter retrospective review of clinical outcomes of patients undergoing alcohol septal ablation to treat LVOT obstruction after TMVR for severe mitral stenosis with severe mitral annular calcification. Six patients underwent percutaneous alcohol septal ablation to treat LVOT obstruction post-TMVR at six different centers. Five patients had immediate significant reduction in LVOT obstruction with improvement in hemodynamic status while one had persistent LVOT gradient but hemodynamic instability improved. The first patient died on postoperative day 4 due to complete heart block. One patient had initial improvement in LVOT gradient with recurrence on postoperative day 1 thought to be secondary to septal edema, was treated with surgical removal of the transcatheter valve and resection of the anterior mitral leaflet followed by transatrial TMVR and died 3 weeks later due to multi-organ failure. The remaining four patients improved clinically after alcohol septal ablation, were discharged from the hospital and were clinically stable at 30-day follow-up. Percutaneous alcohol ablation provides acute relief of TMVR-induced LVOT obstruction when septal hypertrophy is a contributing factor. This may be a safer alternative to bail-out surgery in this extremely high-risk patient population. © 2017 Wiley Periodicals, Inc.

Left ventricular outflow tract obstruction may occur following transcatheter mitral valve replacement in the setting of mitral annular calcification. We present a case series whereby preemptive septal radiofrequency ablation (RADIO-TMVR) was used to augment the left ventricular outflow tract for transcatheter mitral valve replacement in 4 patients at risk for left ventricular outflow tract obstruction despite alcohol septal ablation. All patients were female, average age of 74.9 (68.8-80.4) years. Baseline ejection fraction was 71% (63%-75%). Mean mitral valve area was 1.28 (range, 1.0-1.59) cm2. Mean mitral valve gradient at rest was 9.5 (range, 7-11) mm Hg. New York Heart Association symptoms were III to IV at baseline. Patients underwent preemptive septal radiofrequency ablation to prevent left ventricular outflow tract obstruction with transcatheter mitral valve replacement a range between 69 and 154 days after alcohol septal ablation. Procedural time was 384 (337-424) minutes with a fluoroscopic time of 31 (14-71) minutes. Radiofrequency ablation time was 132 (100-175) minutes. As anticipated, 3 patients developed complete heart block and underwent pacemaker implantation, whereas 1 had a preexisting pacemaker. One patient developed groin hematoma and heart failure exacerbation. There were no peri-procedural deaths. Preemptive septal radiofrequency ablation to prevent left ventricular outflow tract obstruction with transcatheter mitral valve replacement resulted in septal end-diastolic wall thickness reduction compared with baseline (28.6%, 30.4%, 30.3%, and 11.1%) and following alcohol septal ablation (23.1%, 12%, 8.5%). Valve replacement in the setting of mitral annular calcification was performed in all patients 89 (range, 38-45) days after preemptive septal radiofrequency ablation to prevent left ventricular outflow tract obstruction with transcatheter mitral valve replacement. Two patients had concomitant laceration of the anterior mitral leaflet to further augment the neo-left ventricular outflow tract. Postprocedure, New York Heart Association symptoms improved to class I (3 patients) and class II (1 patient). In at-risk individuals, preemptive septal radiofrequency ablation may be an effective strategy at preventing left ventricular outflow tract obstruction with transcatheter mitral valve replacement.

In silico modeling has been proposed as a tool to simulate left ventricular (LV) outflow tract (LVOT) obstruction in patients undergoing transcatheter mitral valve replacement (TMVR). This study validated a simplified approach to simulate LV outflowhemodynamics in the setting of TMVR with anterior leaflet laceration, a clinical technique used to mitigate the risk of LVOT obstruction. Personalized, 3-dimensional computational fluid dynamics models were developed from computed tomography images of six patients who underwent TMVR with anterior leaflet laceration. LV outflow hemodynamics were simulated using the patient-specific anatomy and the peaksystolic flow rate as boundary conditions. The peak outflow velocity, a clinically relevant hemodynamic metric, was extracted from each simulation (vsim-peak) and compared with the clinical measurement from Doppler echocardiography (vclin-peak) for validation. In silico models were successfully developed and implemented for all patients. The pre-processing time was 2h per model and the simulation could be completed within 3h. In three patients, the lacerated anterior leaflet exposed open cells of the transcatheter valve to flow. Good agreement was obtained between vsim-peak and vclin-peak (r = 0.97, p < 0.01) with average discrepancies of 5 ± 2% and 14 ± 1% for patients with exposed and unexposed cells of the transcatheter valve, respectively. The proposed in silico modeling paradigm therefore simulated LVoutflow hemodynamics in a time-efficient manner and demonstrated good agreement with clinical measurements. Future studies should investigate the ability of this paradigm to support clinical applications.

Left ventricular (LV) outflow tract (LVOT) obstruction increases mortality in patients undergoing transcatheter mitral valve implantation (TMVI) in degenerated bioprostheses, annuloplasty rings, and native mitral valves. We aimed to evaluate the LVOT area after TMVI using 3-dimensional (3D) transesophageal echocardiography (TEE) and to investigate the preprocedural cardiac geometry that affects the LVOT area after TMVI. We retrospectively reviewed echocardiography data in 43 patients who had TMVI. A change in pressure gradient across LVOT from before to after TMVI (∆PG) and postprocedure 3D LVOT cross-sectional area at the level of the most distal portion of the mitral valve stent that was closest to the LV apex were assessed as evidence of LVOT narrowing. Transcatheter mitral valve implantation with the use of balloon-expandable valve system was performed for 24 bioprostheses, 7 annuloplasty rings, and 12 native valves. Compared to patients without increase in LVOT gradient (∆PG <10mm Hg; n=33), patients with increase in LVOT gradient (∆PG ≥10mm Hg; n=10) had smaller LV end-systolic volume (LVESV), greater LV ejection fraction (LVEF), and smaller aorto-mitral (AM) angle. The LVOT area at the valve stent distal edge showed strong association with ∆PG (r=-.68, P<.0001). Only a small AM angle was associated with a small LVOT area at the valve stent distal edge on multivariable analysis, independent of LVESV and LVEF. Small LV size, preserved LVEF, and small AM angle were associated with LVOT narrowing. 3D-derived AM angle might be independently associated with LVOT narrowing in patients undergoing transcatheter mitral valve-in-valve, valve-in-ring, and valve-in-native valve implantation, independent of LVESV and LVEF.

Transcatheter mitral valve replacement (TMVR) has become a viable, minimally invasive treatment for inoperable patients with severe mitral valve disease, particularly among elderly individuals with significant comorbidities. A key complication of TMVR is left ventricular outflow tract (LVOT) obstruction, necessitating various preventive and therapeutic strategies. This report presents a case of severe LVOT obstruction following TMVR and highlights the effective application of the kissing balloon technique as a therapeutic intervention. A 79-year-old female with New York Heart Association Class IV dyspnoea due to severe mitral stenosis and a high operative risk, with a Society of Thoracic Surgeons Risk of Mortality (STS-PROM) score of 6.2%, underwent TMVR. Pre-procedural evaluations indicated significant mitral valve calcification and a mitral valve area of 0.9 cm². After successful TMVR deployment, post-implantation echocardiography revealed an LVOT pressure gradient of 53/85 mmHg, prompting the use of the kissing balloon technique, which reduced the gradient to 28 mmHg. Follow-up assessments showed normal mitral valve function and stable LVOT gradients during short-term follow-up throughout the patient's hospital stay. Left ventricular outflow tract obstruction is a potentially life-threatening complication of TMVR, often associated with high mortality rates due to haemodynamic impairment. This complication can arise from various anatomical factors and valve positioning issues. Several strategies have been developed to address LVOT obstruction, including the laceration of the anterior mitral leaflet and alcohol septal ablation. The successful implementation of the kissing balloon technique in this case underscores its potential to improve outcomes in LVOT obstruction.

New ESC guidelines on hypertrophic cardiomyopathy: new insights in invasive treatment?

To evaluate sex differences in in-hospital mortality and 90-day readmission rates among patients undergoing transcatheter mitral valve replacement (TMVR) in the United States of America. Women have higher rates of mortality and rehospitalization than men following many cardiac procedures. TMVR has grown as an alternative to mitral valve surgery for patients at high surgical risk. The rates of TMVR mortality and rehospitalization by sex are unknown. We analyzed the Nationwide Readmissions Database (NRD) from 2016 to 2019 to identify hospitalizations for TMVR. Sex differences in in-hospital mortality and 90-day readmissions were determined using logistic regression models. Between 2016 and 2019, 4109 hospitalizations for TMVR were identified, comprised of 1758 (42.8%) men and 2351 (57.2%) women. The median age was 74 years for both men and women. There was no significant difference in in-hospital mortality during index hospitalization (6.51% vs. 6.69%;p = 0.852) and all-cause 90-day readmission (28.19% vs. 29.59%;p = 0.563) between men and women. Across the study period, trend analysis did not reveal a significant change in in-hospital mortality (men p = 0.087, women p = 0.194) or 90-day readmission rates (men p = 0.569, women p = 0.454). In patients undergoing TMVR, in-hospital mortalityand 90-day readmissions are similar between men and women. Between 2016 and 2019, TMVR in-hospital mortality and 90-day readmission rates remained unchanged. Further research is necessary to confirm these findings.

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. 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. 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. 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. 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.

ECHOCARDIOGRAPHIC ASSESSMENT OF LEFT VENTRICULAR OUTFLOW TRACT AFTER TRANSCATHETER MITRAL VALVE REPLACEMENT

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

Left ventricle outflow tract obstruction (LVOTO) is the main limitation of transcatheter mitral valve replacement (TMVR) procedure occurring in 7%-9% of cases and responsible of 25% TMVR screen failures. We aim to assess the alcohol septal ablation (ASA) effect on LVOTO risk before TMVR by multistage cardiac computed tomography (CT). Patients indicated for TMVR procedure using Sapiens 3 Prosthesis with high LVOTO risk were enrolled in the study. ASA was the first choice technique to reduce this risk based on multiple and staged cardiac CT screening. Out of 29 consecutive TMVR procedures conducted in our center between March 2021 and April 2023, nine patients presented high LVOTO risk and were enrolled in our study. The main risk factor retained was a reduced predicted NeoLVOT surface 89 mm2 [66-135] (< 170 mm2). Most procedures were valve in MAC and all patients underwent at least one ASA. CT control showed a significant increase by 95% in the predicted NeoLVOT surface: 174 mm2 [121-240]; p = 0.012 compared to the baseline value. There were no significant paraprosthesis leakage or LVOTO found on TTE according to the MVARC criteria. Cardiac CT showed a larger than predicted final NeoLVOT surface: 215 mm2 [175-317]; p = 0.018. One patient died after ASA, and two others during the first year of follow-up. Survivors had significant symptom relief (p = 0.046) and a decreased PASP (38 mmHg [32-47] vs. 54 mmHg [46-62.5]; p = 0.028). Multistage CT analysis shows that ASA is effective in high LVOTO-risk patients undergoing TMVR.

Demonstrate proof-of-concept validation of a computed tomography (CT) computer-aided design prediction modeling tool to identify patients at risk for left ventricular outflow tract (LVOT) obstruction in transcatheter mitral valve replacement (TMVR). LVOT obstruction is a significant and even fatal consequence of TMVR. From August 2013 to August 2017, 38 patients in 5 centers underwent TMVR with compassionate use of balloon-expandable valves for severe mitral valve dysfunction because of degenerative surgical mitral ring, bioprosthesis, or severe native mitral stenosis from to severe mitral annular calcification. All patients had preprocedural CT scans performed for anatomic screening, intraprocedural TEE and invasive hemodynamics performed. Preprocedural prediction modeling was performed utilizing computer-aided design (CAD) of the neo-LVOT post-TMVR. Post-TMVR CT scans were obtained and compared to pre-TMVR LVOT modeling datasets for validation. All patients underwent successful TMVR without device embolization. Seven of the 38 patients experienced LVOT obstruction, defined as an increase of ≥10 mmHg LVOT peak gradient post-TMVR. Anatomic screening using CT was validated in 20/38 patients as preprocedural predicted neo-LVOT surface area correlated well with post-TMVR measurements (R2 = 0.8169, P < 0.0001). A receiver operating curve curve found a predicted neo-LVOT surface area of ≤ 189.4 mm2 to have 100% sensitivity and 96.8% specificity for predicting TMVR-induced LVOT obstruction. CAD design and CT postprocessing are indispensable tools in predicting LVOT obstruction and necessary for anatomic screening in percutaneous TMVR.