Evaluation of cardiac beat synchronization control for a rotary blood pump on valvular regurgitation with a mathematical model.

We have studied the cardiac beat synchronization (CBS) control for a rotary blood pump (RBP) and revealed that it can promote pulsatility and reduce cardiac load. Besides, patients with LVAD support sometimes suffer from aortic and mitral regurgitation (AR and MR). A control method for the RBP should be validated in wider range of conditions to clarify its benefits and pitfalls prior to clinical application. In this study, we evaluated pulsatility and cardiac load reduction obtained with the CBS control on valvular failure conditions with a mathematical model. Diastolic assist could reduce cardiac load on the left ventricle by decreasing external work of the ventricle even in MR cases while it was not so effective in AR cases. Systolic assist can still promote pulsatility in AR and MR cases; however, aortic valve function should be carefully confirmed since pulse pressure can be wider not due to systolic assist but to AR.

Can the intermittent low-speed function of left ventricular assist device prevent aortic insufficiency?

Aortic insufficiency (AI) is known to associate with a persistently closed aortic valve during continuous-flow ventricular assist device support. Some devices carry an intermittent low-speed (ILS) function, which facilitates aortic valve opening, but whether this function prevents AI is unknown. In this study, the Jarvik 2000 device, which is programmed to reduce the pump speed each minute for 8 s, was chosen to examine this potential effect. Prospectively collected data of 85 heart transplant-eligible Jarvik 2000 recipients who met the study criteria (no pre-existing AI and aortic valve surgery) were retrospectively analyzed for the incidence, correlating factors, and clinical outcomes of de novo AI. All data were provided by the Japanese Registry for Mechanically Assisted Circulatory Support. De novo AI occurred in 58 patients, 23 of whom developed at least moderate AI during a median support duration of 23.5 months. Freedom from moderate or greater AI was 84.4%, 66.1% and 60.2% at 1, 2 and 3 years, respectively. Multivariate analyses revealed that progressive AI was correlated with decreased pulse pressure after implantation (hazard ratio 1.060, 95% confidence interval 1.001-1.127, p = 0.045). No correlation was found for mortality or other adverse events, including stroke, bleeding, infection, pump failure, hemolysis, and readmission. The benefit of the Jarvik 2000's current ILS mode against AI appears to be minimal. However, in this limited cohort where all recipients underwent implantation as a bridge to transplantation, the impact of de novo progressive AI on other clinical adversities was also minimal.

Early Ventricular Septal Defect Closure Prevents the Progression of Aortic Regurgitation: A Long-Term Follow-Up Study.

According to current short-term evidence, ventricular septal defect (VSD) closure should be performed as early as possible after aortic regurgitation (AR) diagnosis in pediatric patients to prevent AR progression. However, long-term follow-up data are lacking. Therefore, our aim was to evaluate the long-term follow-up (≥ 10 years) of patients who underwent VSD closure as early as possible after AR diagnosis and to evaluate whether early VSD closure prevents progression of AR. This was a retrospective cohort study of 42 patients with VSD and AR who had undergone VSD closure at a median age of 2.9 years, with a median waiting period from AR diagnosis to VSD closure of 3.4 months and follow-up of a median 13.1 years (interquartile range 10.0-15.8 years). The preoperative degree of AR was trivial in 25 patients, mild in 15, and moderate in 2. Of the 33 patients followed up for ≥ 10 years, none required aortic valve replacement and there was no incidence of mortality. The degree of AR improved or did not change, except in 1 patient. The size of the VSD (odds ratio [OR] 0.85; 95% confidence interval [CI] 0.62-1.18; p = 0.33), time from diagnosis to surgery (OR 1.00; 95% CI 1.000-1.001; p = 0.657), and age at the time of surgery (OR 1.00; 95% CI 0.998-1.004; p = 0.452) were not predictive of persistent postoperative AR. Therefore, VSD closure performed as early as possible after AR diagnosis could successfully prevent AR progression in patients with less than moderate preoperative AR, eliminating the need for aortic valve replacement and valvuloplasty.

A new technique that prevents paravalvular leakage after aortic valve replacement using a rapid-deployment valve system.

BACKGROUND: We report our 1-year single-center experience of a new technique of aortic valve replacement using a rapid-deployment valve (RD-AVR) to avoid postoperative complications. We also report the unexpected pitfalls and handling techniques that we have seen in past cases. METHODS: We performed aortic valve replacement on 38 patients between May 2019 and April 2020. Their mean age was 74 years. The primary outcomes were in-hospital mortality and short-term results during a 1-year follow-up period, while the secondary outcomes were related to prosthetic valve function, especially paravalvular leakage (PVL). We further analyzed the relationship between the new technique and its outcomes. RESULTS: The mean operative time was 196 min. There were no in-hospital deaths, and the mean duration of postoperative hospital stay was 11.8 days. Valvular measurements using three-dimensional computed tomography were larger and more accurate than those measured using ultrasonic echocardiography. Postoperative RD-AVR prosthetic valve function was excellent. However, PVL occurred in four cases 1 week and 1 year postoperatively and regurgitation did not improve. A gap associated with PVL was identified below the right-noncoronary commissure. To prevent PVL, we additionally stitched this gap in the later 18 cases; there was no case of PVL and no new pacemaker implantation in these cases. CONCLUSIONS: PVL is more likely to occur if there is a gap below the R-N commissure, especially in cases with a large annulus; therefore, applying an additional stitch to the R-N commissure is extremely useful.

Optimal positioning of self-expanding valves before deployment decreases paravalvular regurgitation following transcatheter aortic valve replacement.

OBJECTIVES: To evaluate the association between measurements performed during Medtronic CoreValve (MCV) deployment and paravalvular leak (PVL). BACKGROUND: The MCV can be recaptured and repositioned, allowing the TAVR operator to implant at a more favorable position. The association between angiographic measurements of MCV position while the valve is recapturable and PVL post deployment has not been investigated. METHODS: 493 patients undergoing TAVR with MCV (January 2011-July 2017) were included. PVL was defined as intraprocedural aortic regurgitation that was judged clinically to require balloon postdilation. Depth of the valve at the left coronary cusp (LCC) and noncoronary cusp (NCC) were measured when the valve was 80% deployed. An optimal cutoff value for the ratio LCC/NCC for PVL was identified in 40 patients. Using this cutoff value, the association between LCC/NCC and PVL was then validated in 453 patients. RESULTS: The median LCC/NCC was 1.51 (interquartile range 1.06-1.89).The optimal cutoff value for LCC/NCC was 1.48 (93% sensitivity, 77% specificity, AUC0.85). In the validation group 112 (24.7%) patients had PVL. For LCC/NCC ≥ 1.48, the incidence of PVL was lower compared to LCC/NCC < 1.48 (9.58% vs. 41.78%, P < 0.0001). LCC/NCC of 1.48 had a sensitivity of 79.5% and specificity of 63.6% for PVL (AUC0.72). In a multivariate model, LCC/NCC < 1.48 independently predicted PVL (OR = 6.67, 95% CI 3.96-11.23, P < 0.0001). CONCLUSION: Positioning the MCV such that the LCC/NCC is ≥1.48 may result in less PVL.

Determinants of success and hemodynamic impact of balloon postdilatation of self-expanding transcatheter aortic valves.

OBJECTIVES: To explore the rate, the determinants of success, and the hemodynamic impact of balloon postdilatation (BPD) of self-expanding transcatheter heart valves (SE-THVs) BACKGROUND: BPD is commonly used to optimize valve expansion and reduce paravalvular leakage (PVL) after transcatheter aortic valve implantation (TAVI) without clearly knowing its hemodynamic benefits. METHODS: Patients (n = 307) who received a SE-THV were stratified according to whether a BPD was performed or not. Patients who received BPD were stratified according to the severity of PVL remaining after BPD into two groups: Successful BPD (≤mild PVL + BPD) and Failed BPD (moderate-severe PVL + BPD). RESULTS: BPD was performed in 121 patients (39.4%) and was successful in 106 patients (87.6% of attempts). A ratio of the postdilatation balloon diameter to the annulus diameter ≤0.95 was an independent predictor of BPD failure (OR: 10.72 [2.02-56.76], P = .005). Peak transvalvular pressure gradient (PG) was lower in the Successful BPD group (14[12-22] mm Hg) than in the Failed BPD group (18[16-23] mm Hg, P = .029), and did not rise in either group during follow-up (median [IQR], 364[161-739] days). CONCLUSION: BPD was performed in 39% of patients who received a SE-THV, and was successful in the majority of attempts. BPD failure was more likely in patients with a small postdilatation balloon-to-annulus diameter ratio. Effective BPD improved THV hemodynamic performance, and this was maintained in the intermediate-term post-TAVI.

Advantage of Pulsatility in Left Ventricular Reverse Remodeling and Aortic Insufficiency Prevention During Left Ventricular Assist Device Treatment.

BACKGROUND: A continuous flow (CF) left ventricular assist device (LVAD) has various advantages over a pulsatile flow (PF) LVAD, but the extent of preventing aortic insufficiency (AI) by each type of LVAD remains controversial. METHODS AND RESULTS: Of 86 patients with non-ischemic cardiomyopathy who underwent LVAD implantation between 2006 and 2015, 20 propensity score-matched patients with PF LVADs and 20 with CF LVADs were enrolled in this study. There were no significant differences in the baseline variables of both groups. During the 6-month LVAD treatment, the LV ejection fraction of the PF group was significantly higher than that of the CF group; the PF group also had a wider pulse pressure and less enlargement of the aortic root (P<0.05 for all). Patients in the PF group experienced more frequent opening of the native aortic valve and less AI than those in the CF group (P<0.05 for both). The PF LVAD was explanted in 5 patients (25%), and a CF LVAD was explanted in 1 patient (5%). CONCLUSIONS: Compared with CF LVADs, PF LVADs seem to have an advantage in improving LV reverse remodeling and preventing AI. It may be best to incorporate pulsatility into current CF LVADs while retaining their existing benefits.

Open issues in transcatheter aortic valve implantation. Part 2: procedural issues and outcomes after transcatheter aortic valve implantation.

This article provides an overview on procedure-related issues and uncertainties in outcomes after transcatheter aortic valve implantation (TAVI). The different access sites and how to select them in an individual patient are discussed. Also, the occurrence and potential predictors of aortic regurgitation (AR) after TAVI are addressed. The different methods to quantify AR are reviewed, and it appears that accurate and reproducible quantification is suboptimal. Complications such as prosthesis-patient mismatch and conduction abnormalities (and need for permanent pacemaker) are discussed, as well as cerebrovascular events, which emphasize the development of optimal anti-coagulative strategies. Finally, recent registries have shown the adoption of TAVI in the real world, but longer follow-up studies are needed to evaluate the outcome (but also prosthesis durability). Additionally, future studies are briefly discussed, which will address the use of TAVI in pure AR and lower-risk patients.

Modeling study of aortic root for ross procedure: a structural finite element analysis.

BACKGROUND AND AIM OF THE STUDY: The Ross procedure involves replacing the diseased aortic valve with the patient's own pulmonary valve (autograft) to form the neoaortic valve, reimplanting the coronary arteries, and inserting a cadaveric homograft into the pulmonary position. METHODS: In order to model a neoaortic root for the Ross procedure in patients with aortic valve disease, the three-dimensional geometry of a reference aortic valve was reconstructed (reference model A). The diameters of the sinotubular junction (STJ) and maximum sinus were then modified to create four geometric models named B, C, D, and E, with different dimensions. The mechanical behavior of the aortic root was simulated, and the performance of the aortic leaflets assessed in terms of maximum geometric orifice area (GOA) during all cardiac cycle and leaflet contact pressure during closing phase. RESULTS: The neoaortic valve model showed a maximum GOA of 274.4 mm2 and a maximum leaflet stress of 682 kPa. For models B and C, the leaflet contact pressure was increased by 27.4% and decreased by 4.42%, with STJ diameter increased 1.1-fold and decreased 0.9-fold compared to reference model A. The leaflet contact pressure in models D and E was increased by 3.04% and decreased by 11.5%, while the sinus diameter was increased 1.1-fold and decreased 0.9-fold compared to model A. CONCLUSION: Increasing the STJ and sinus diameters within a range of 10% can increase the leaflet contact pressure for the aortic root, and vice versa. This may be the reason why neoaortic valve insufficiency occurs long after patients have undergone the Ross procedure.

V-shape reduction plasty to reduce the neoaortic root-ascending aorta discrepancy in children undergoing arterial switch operation.

Preoperative aortopulmonary mismatch is considered a risk factor for the development of aortic insufficiency after surgery for transposition of the great arteries. We have approached these children using a neoaortic root reduction plasty. Five children with severe PA-AO discrepancy (median age 57 days) underwent arterial switch operation (ASO) associated with a V-shape neoaortic reduction plasty. At follow-up aortic regurgitation remains stable in all patients and no supra-aortic obstruction and/or neoaortic root dilatation were observed.

Renal sympathetic denervation suppresses de novo podocyte injury and albuminuria in rats with aortic regurgitation.

BACKGROUND: The presence of chronic kidney disease is a significant independent risk factor for poor prognosis in patients with chronic heart failure. However, the mechanisms and mediators underlying this interaction are poorly understood. In this study, we tested our hypothesis that chronic cardiac volume overload leads to de novo renal dysfunction by coactivating the sympathetic nervous system and renin-angiotensin system in the kidney. We also examined the therapeutic potential of renal denervation and renin-angiotensin system inhibition to suppress renal injury in chronic heart failure. METHODS AND RESULTS: Sprague-Dawley rats underwent aortic regurgitation and were treated for 6 months with vehicle, olmesartan (an angiotensin II receptor blocker), or hydralazine. At 6 months, albuminuria and glomerular podocyte injury were significantly increased in aortic regurgitation rats. These changes were associated with increased urinary angiotensinogen excretion, kidney angiotensin II and norepinephrine (NE) levels, and enhanced angiotensinogen and angiotensin type 1a receptor gene expression and oxidative stress in renal cortical tissues. Aortic regurgitation rats with renal denervation had decreased albuminuria and glomerular podocyte injury, which were associated with reduced kidney NE, angiotensinogen, angiotensin II, and oxidative stress. Renal denervation combined with olmesartan prevented podocyte injury and albuminuria induced by aortic regurgitation. CONCLUSIONS: In this chronic cardiac volume-overload animal model, activation of the sympathetic nervous system augments kidney renin-angiotensin system and oxidative stress, which act as crucial cardiorenal mediators. Renal denervation and olmesartan prevent the onset and progression of renal injury, providing new insight into the treatment of cardiorenal syndrome.

Three-dimensional multidetector computed tomography versus conventional 2-dimensional transesophageal echocardiography for annular sizing in transcatheter aortic valve replacement: Influence on postprocedural paravalvular aortic regurgitation.

OBJECTIVES: In transcatheter aortic valve replacement (TAVR), the influence of aortic annular assessment with either multidetector computed tomography (MDCT) or conventional transesophageal echocardiography (TEE) on the incidence of postprocedural paravalvular aortic regurgitation (PAR) was evaluated. BACKGROUND: PAR remains a major limitation in TAVR. Appropriate selection of transcatheter heart valve (THV) size is crucial to prevent PAR. METHODS: Outcomes following TAVR with a balloon-expandable THV were compared in two retrospective cohorts identified according to whether THV size selection was based on TEE (study group 1, n = 80) or MDCT (study group 2, n = 58). RESULTS: The two study groups were comparable with regard to baseline clinical, risk score, and echocardiographic characteristics. The incidence of moderate/severe PAR was lower in study group 2 than in group 1, 8.6% versus 28.8% (P < 0.01). The difference between the THV nominal diameter and MDCT annular diameter was predictive of moderate/severe PAR (AUC 0.84; 95% CI: 0.72-0.92). Neither age, gender, body mass index, annular eccentricity index, aortic valve calcification nor the difference between the THV diameter and the TEE annular diameter predicted postprocedural PAR. Increased THV oversizing relative to the MDCT mean annular diameter was associated with reduced severity of PAR. No difference in perprocedural complications between two study groups was observed. CONCLUSION: MDCT-based annular sizing in TAVR significantly reduces postprocedural PAR, and THV oversizing appears pivotal in this aspect. Further delineation of the optimal degree of THV oversizing is needed.

Development of a novel drive mode to prevent aortic insufficiency during continuous-flow LVAD support by synchronizing rotational speed with heartbeat.

Aortic insufficiency (AI) is a serious complication for patients on long-term support with left ventricular assist devices (LVAD). Postoperative aortic valve opening is an important predictor of AI. A system is presently available that can promote native aortic flow by reducing rotational speed (RS) for defined intervals. However, this system can cause a reduction in pump flow and lead to insufficient support. We therefore developed a novel "delayed copulse mode" to prevent AI by providing both minimal support for early systole and maximal support shortly after aortic valve opening by changing the RS in synchronization with heartbeat. To evaluate whether our drive mode could open the aortic valve while maintaining a high total flow (sum of pump flow and native aortic flow), we installed a centrifugal LVAD (EVAHEART(®); Sun Medical) in seven goats each with normal hearts and acute LV dysfunction created by micro-embolization of the coronary artery. We intermittently switched the drive mode from continuous (constant RS) with 100 % bypass to delayed copulse mode with 90 % bypass. Total flow did not significantly change between the two modes. The aortic valve opened when the delayed copulse mode was activated. The delayed copulse mode allowed the aortic valve to open while maintaining a high total flow. This novel drive mode may considerably benefit patients with severe heart failure on long-term LVAD support by preventing AI.

Innovations and novel technologies in TAVI. Second generation transcatheter heart valves.

Transcatheter aortic valve implantation (TAVI) is the new standard-of-care for inoperable patients with superior outcome compared to conservative management including balloon valvuloplasty. In high-risk patients, TAVI has shown non-inferiority compared with surgical aortic valve replacement. Although data from national multi-centre registries are very encouraging and use of TAVI in intermediate risk patients has been discussed, it is of note that the commercially available and currently used transcatheter heart valves (THV) have not yet been assessed by randomized clinical trials in those patients. New technology advances promise to simplify TAVI and to improve outcome by reducing the rate of TAVI-specific issues such as paravalvular aortic regurgitation (PAR), annular rupture, and conduction disturbances. A reduction in the incidence and severity of PAR represents an obvious target for technical improvements in the design of upcoming "next generation" THVs and of implantation techniques including repositioning/recapturing features, paravalvular sealing techniques, and precise peri-interventional imaging modalities.

Drivers of vascular growth and remodeling: A computational framework to promote benign adaptation in the Ross procedure.

In the sixties, Dr Donald Ross designed a surgical solution for young patients with aortic valve disease by using the patients' own pulmonary valve. The Ross procedure is the only aortic valve replacement technique that can restore long-term survival and preserve quality of life. The main failure mode of the Ross procedure is wall dilatation, potentially leading to valve regurgitation and leakage. Dilatation occurs due to the inability of the pulmonary autograft to adapt to the sudden increase in loading when exposing to aortic pressures. Previous experimental data has shown that a permanent external support wrapped around the artery can prevent the acute dilatation of the arterial wall. However, the textile support leads to stress-shielding phenomena due to the loss of mechanical wall compliance. We present a pragmatic and modular computational framework of arterial growth and remodeling predicting the long-term outcomes of cardiovascular tissue adaptation, with and without textile wrapping. The model integrates mean, systolic and diastolic pressures and assumes the resulting wall stresses to drive the biological remodeling rules. Rather than a single mean pressure or stress deviation from the homeostatic state, we demonstrate that only pulsatile stresses can predict available experimental results. Therefore, we suggest that a biodegradable external support could induce benign remodeling in the Ross procedure. Indeed, a biodegradable textile wrapped around the autograft fulfills the trade-off between prevention of acute dilatation on the one hand and recovery of arterial wall compliance on the other hand. After further validation, the computational framework can set the basis for the development of an actual biodegradable external support for the Ross procedure with optimized polymer mechanical properties and degradation behavior.

Aortic regurgitation in Marfan syndrome patients who underwent prophylactic surgery: A single-center experience.

BACKGROUND: Marfan syndrome is an inherited connective tissue disease that causes aortic root dilatation and dissection and requires surgical intervention. Apart from emergent surgery for aortic dissection or aortic aneurysmal rupture, prophylactic surgical intervention can also be administered, depending on the severity of aortic root dilatation. The direct relationship between surgical intervention and aortic regurgitation was seldom mentioned in previous studies. METHODS: A retrospective cohort study was designed to determine the clinical presentations of prophylactic surgery in patients with Marfan syndrome. Between January 2009 and May 2019, 112 patients, adolescents and young adults, treated in the Department of Pediatric Cardiology of Taipei Veterans General Hospital, were enrolled. All patients' sex, body measurements, echocardiography reports, and surgical notes were collected for statistical analysis. RESULTS: Among the participants, nine patients (8%) underwent the Bentall procedure, and the other 103 did not receive surgical intervention. The operation group had a larger aortic root size (4.89 vs 2.86 cm, p < 0.001), more dilated left ventricle (4.81 vs 4.1 cm, p = 0.002), and higher prevalence of moderate and severe aortic regurgitation (66% vs 1%, p < 0.001) than the nonoperation group. CONCLUSION: Among adolescents and young adults with Marfan syndrome, echocardiographic presentation of aortic root dilatation, left ventricular dilatation, and significant aortic regurgitation was significantly associated with prophylactic surgical intervention. According to the study, significant aortic regurgitation should also be considered as an important indication for prophylactic surgery.

A modified technique for performing proximal anastomosis of a supracoronary graft.

An aortic aneurysm may cause loss of the sinotubular junction. Reduction in the diameter of the sinotubular junction may reestablish aortic valve competence in patients with an ascending aortic aneurysm and aortic valve regurgitation with normal aortic cusps. With this video tutorial we describe an alternative technique for replacing the ascending aorta with restoration of the sinotubular junction.

Novel Pressure-Regulated Deployment Strategy for Improving the Safety and Efficacy of Balloon-Expandable Transcatheter Aortic Valves.

OBJECTIVES: The authors propose a novel pressure-regulated method for balloon-expandable transcatheter heart valve (THV) deployment, aimed at optimizing prosthesis-annulus apposition while preventing significant tissue injury. BACKGROUND: The optimal method for balloon-expandable THV deployment remains debated. Current protocols are volume dependent, relying on under- and overfilling of the deployment apparatus. During deployment, the annular wall tension exerted by the expanding prosthesis is determined by maximal THV diameter and balloon pressure (Laplace's law). METHODS: Three hundred thirty consecutive patients with severe native aortic stenosis who underwent TAVR with SAPIEN 3 THVs were included. One hundred and six patients were considered at high risk for annular rupture. THVs were deployed until reaching a predetermined balloon pressure. Postdilatation was performed to reduce mild or greater angiographic paravalvular regurgitation (PVR). Using a biomechanical model, annular wall stress was estimated for each case and assessed against rates of postdilatation, mild or greater PVR on transthoracic echocardiography, new permanent pacemaker placement or left bundle branch block, and annular rupture. RESULTS: Patients with wall stress >3 MPa had reduced postdilatation rate (P < 0.001) and reduced final PVR (P = 0.014). Annular rupture occurred in 2 of 3 high-risk patients with wall stress >3.5 MPa (3.69 and 3.84 MPa); no rupture occurred in 95 high-risk patients with wall stress ≤3.5 MPa. We defined a single target deployment pressure per THV size to ensure deployment within target wall stress levels of 3 to 3.5 MPa: 6.25 atm for 23-mm THVs, 5.5 atm for 26-mm THVs, and 5 atm for 29-mm THVs. Patients within this target range (n = 136) had a 10.0% postdilatation rate, 12.7% mild PVR, and no moderate to severe PVR. The relationship between balloon filling volume and associated pressure and wall stress was inconsistent. CONCLUSIONS: Pressure-regulated THV deployment is a simple, reproducible, safe, and effective method, regardless of high-risk anatomical complexities.