Mid-term function and remodeling potential of tissue engineered tricuspid valve: Histology and biomechanics

ObjectiveTricuspid valve reconstruction using a small intestinal submucosal porcine extracellular matrix (ECM) tube graft is hypothesized to be durable for six months and show signs of recellularization and growth potential. The purpose was to histologically and biomechanically test ECM valves before and after six months of implantation in pigs for comparison with native valves.MethodsTen 60 kg pigs were included, which survived tricuspid valve tube graft insertion. Anterior and septal tricuspid leaflets were explanted from all animals surviving more than one month and examined histologically (n = 9). Endothelialization, collagen content, mineralization, neovascularization, burst strength and tensile strength were determined for native valves (n = 5), ECM before implantation (n = 5), and ECM after six months (n = 5).ResultsCollagen density was significantly larger in ECM at implantation (baseline) compared to native leaflet tissue (0.3 ± 0.02 mg/mm³ vs. 0.1 ± 0.03 mg/mm³, p < .0001), but collagen density decreased and reached native leaflet collagen content, six months after ECM implantation (native vs. ECM valve at six months: 0.1 ± 0.03 mg/mm³ vs. 0.2 ± 0.05 mg/mm³, p = .8).Histologically, ECM valves showed endothelialization, host cell infiltration and structural collagen organization together with elastin generation after six months, indicating tissue remodeling and -engineering together with gradual development of a close-to-native leaflet structure without foreign body response.ConclusionsECM tricuspid tube grafts were stronger than native leaflet tissue. Histologically, the acellular ECM tube grafts showed evidence of constructive tissue remodeling with endothelialization and connective tissue organization. These findings support the concept of tissue engineering and recellularization, which are prerequisites for growth.     

全软成形环与缘对缘瓣膜成形术在心脏瓣膜关闭不全成形术中的疗效比较

目的:观察和比较全软成形环与缘对缘瓣膜成形术在心脏瓣膜关闭不全成形术中的疗效。方法:回顾性研究我院行心脏瓣膜关闭不全成形术患者80例,随机分为Ⅰ组与Ⅱ组,每组各40例。第Ⅰ组患者在行心脏瓣膜关闭不全成形术中使用全软成形环进行治疗,第Ⅱ组患者在手术过程进行缘对缘瓣膜成形术。比较治疗前后两组患者二尖瓣口、二尖瓣环面积和收缩期及舒张期二尖瓣环周径、左心室内径、心搏出量、射血速率、射血时间及临床有效率。结果:治疗后,两组二尖瓣形态、左心室内经、心搏出量、射血速率及射血时间均较治疗前有所改善(P0.05);且与第Ⅱ组相比,第Ⅰ组患者二尖瓣口面积、心搏出量及射血速率较大,二尖瓣环的面积、收缩期及舒张期二尖瓣环周径、左心室内径较小,射血时间明显缩短(P0.05)。第Ⅱ组治疗总有效率为95%,较第Ⅰ组(62.5%)显著升高,差异具有统计学意义(P0.05)。结论:与缘对缘瓣膜成形术相比,全软成形环在心脏瓣膜关闭不全成形术中的疗效更好,其机制可能与增大二尖瓣口面积、心搏出量及射血速率,减小二尖瓣环的面积、收缩期及舒张期二尖瓣环周径、左心室内径,缩短射血时间有关。     

Percutaneous implantation of the CoreValve aortic valve prosthesis in patients at high risk or rejected for surgical valve replacement: Clinical evaluation and feasibility of the procedure in the first 30 patients in the AMC-UvA

Objective. To report the feasibility, safety and efficacy of percutaneous aortic valve implantation (PAVI) with the CoreValve self-expanding aortic valve bioprosthesis in elderly patients with aortic valve stenosis who are rejected for surgery or have a high surgical risk.Methods. PAVI using the CoreValve ReValving System was performed under general anaesthesia in 30 high-risk (surgical) patients with a symptomatic severe aortic valve stenosis.Results. The patients had a mean age of 80.5±7.7 years, a mean aortic valve area of 0.71±0.19 cm², a peak transvalvular aortic gradient of 79±25 mmHg, as measured with echo Doppler, a logistic EuroSCORE of 15±10% and a Society of Thoracic Surgeons (STS) score of 5.2±2.9%. Device success was achieved in all patients and acute procedural success in 27 patients (90%). In the surviving patients, there was in a reduction of the peak aortic pressure gradient from 76±24 mmHg to 22±7 mmHg (n=24, p<0.00001) 30 days after successful device implantation. At 30 days, major adverse cardiovascular and cerebral events had occurred in seven patients (23%). This included mortality in six patients (20%), of which one death was cardiovascular. The other five non-cardiovascular deaths involved two patients who died of an exacerbation of severe pre-existent pulmonary disease and three of infectious complications.Conclusions. Percutaneous aortic valve implantation was successfully performed in our centre in highrisk patients, with a 30-day mortality of 20%. When successful, marked haemodynamic improvement and relief of symptoms was achieved. (Neth Heart J 2010;18:18-24.)     

Assessment of ablation catheter contact on valve annulus: Implications on accessory pathway ablation

BackgroundCatheter-tissue contact force is an important factor influencing lesion size and efficacy and thereby potential for arrhythmia recurrence following accessory pathway (AP) radiofrequency ablation. We aim to evaluate adequacy and perception of catheter contact on the tricuspid and mitral annuli.MethodsData were collected from 42 patients undergoing catheter ablation. Operators were blinded to contact force information and reported perceived contact (poor, moderate, or good) while positioning the catheter at four tricuspid annular sites (12, 9, 6 and 4 o'clock positions; abbreviated as TA12, TA9, TA6 and TA4) and three mitral annular sites (3, 5 and 7 o'clock positions; abbreviated as MA3, MA5 and MA7) through long vascular sheaths.ResultsThe highest and lowest mean contact forces were obtained at MA7 (13.3 ± 1.7 g) and TA12 (3.6 g ± 1.3 g) respectively. Mean contact force on tricuspid annulus (6.1 g ± 0.9 g) was lower than mitral annulus (9.8 ± 0.9 g) locations (p = 0.0036), with greater proportion of sites with <10 g contact force (81.7% vs 60.4%; p = 0.0075). Perceived contact had no impact on measured mean contact force for both mitral and tricuspid annular positions (p = 0.959 and 0.671 respectively). There was correlation of both impedance and atrial electrogram amplitude with contact force, though insufficient to be clinically applicable.ConclusionA high proportion of annular catheter applications have low contact force despite being performed with long vascular sheaths in the hands of experienced operators. In addition, there was no impact of operator perceived contact force on actual measured contact force. This may carry implications for success of AP ablation.     

实时三维经胸超声心动图检测二尖瓣成形术前后左心房功能的变化及临床意义

目的:探讨实时三维经胸超声心动图检测左心房(LA)功能以评价二尖瓣成形术(MVR)疗效的价值。方法:选择87例二尖瓣关闭不全患者(病例组)分别在MVR术前及术后1 w、24 w采取实时三维经胸超声心动图检测LA的最大容积(maximum volume of LA,LAV_(max))、最小容积(the minimum volume of LA,LAV_(min))、收缩前容积(systolic volume,LAV_p)及射血分数(ejection fraction,LAEF)、被动射血分数(passive ejection fraction,LAPEF)及主动射血分数(active ejection fraction,LAAEF)等指标,并与同期80例健康志愿者作对照。结果:病例组术前LAV_(max)I、LAV_(min)I、LAV_pI、LAEF、LAPEF、LAAEF值与对照组比较差异有统计学意义(P0.05),术后1 w、24 w,LAV_(max)I、LAV_(min)I、LAV_pI、LAEF、LAPEF持续改善(P0.05),LAPEF无明显变化(P0.05)。术后24 w,LA严重扩张由术前58.6%降低到12.6%,67.8%发生LA重构。结论:实时三维经胸超声心动图显示MVR术后LA容积与功能好转,对评价MVR的疗效有一定价值。     

Transcatheter tricuspid valve repair: early experience in the Netherlands

BackgroundSymptomatic tricuspid regurgitation (TR) is increasingly prevalent and impairs quality of life and survival, despite medical treatment. Transcatheter tricuspid valve repair (TTVR) has recently become available as a treatment option for patients not eligible for tricuspid valve surgery. In this study we describe the early experience with TTVR in the Netherlands.MethodsAll consecutive patients scheduled for TTVR in two tertiary hospitals were included in the current study. Patients were symptomatic and had severe functional TR. TTVR was performed either with the MitraClip (off-label use) or dedicated TriClip delivery system and device. Procedural success was defined as achievement of clip implantation, TR reduction ≥ 1 grade and no need for re-do surgical or transcatheter intervention. Clinical improvement was evaluated after 4 weeks.ResultsTwenty-one patients (median age 78 years, 33% male, 95% New York Heart Association class ≥ 3, 100% history of atrial fibrillation) underwent TTVR. Procedural success was achieved in 16 patients, of whom 15 reported symptomatic improvement (New York Heart Association class 1 or 2). There was no in-hospital mortality and no major complications occurred. Baseline glomerular filtration rate and TR coaptation gap size were associated with procedural success.ConclusionThe current study showed that TTVR seems a promising treatment option for patients with severe functional TR deemed high risk for surgery. Successful TR reduction is most likely in patients with limited coaptation gap size and strongly determines clinical benefit. Adequate patient selection and timing of treatment seem essential for an optimal patient outcome.Supplementary InformationThe online version of this article (10.1007/s12471-021-01613-3) contains supplementary material, which is available to authorized users.     

冠心病合并缺血性二尖瓣关闭不全的手术方案探讨

目的:探讨适用于冠心病合并缺血性二尖瓣关闭不全的手术方法及临床效果,为心外科手术提供参考。方法:选取2012年2月至2013年5月在我院心脏外科接受手术治疗的冠心病合并缺血性二尖瓣关闭不全的患者31例。根据手术方式的不同,将所选病例分为二尖瓣成形术组和二尖瓣置换术组。术后随访6-24个月,观察并比较患者手术前后的左心房内径(LAD)、舒张末期直径(LVEDD)、收缩末期直径(LVESD)、左心室射血分数(LVEF)及二尖瓣返流面积。结果:围术期死亡1例,手术成功率为96.7%。30例成功获得随访,随访率为98.8%。二尖瓣成形术组并发症的发生率为22.7%,二尖瓣置换术组并发症的发生率为23.3%,两组术后并发症的发生率无显著差异(P0.05)。与手术前相比,两组患者术后的左心房内径变小,左室舒张末直径和收缩末直径增加,左室射血分数升高,二尖瓣反流面积缩少,差异显著且具有统计学意义(P0.05)。结论:对于冠心病合并重度缺血性二尖瓣关闭不全的患者行二尖瓣成形术或置换术应根据患者的实际情况和病理特点选择最佳的手术方案,以提高手术的成功率和安全性。     

CMR-derived TAPSE measurement: a semi-quantitative method of right ventricular function assessment in patients with hypertrophic cardiomyopathy

Aim

To compare cardiovascular magnetic resonance (CMR)-derived right ventricular fractional shortening (RVFS), tricuspid annular plane systolic excursion with a reference point within the right ventricular apex (TAPSE_in) and with one outside the ventricle (TAPSE_out) with the standard volumetric approach in patients with hypertrophic cardiomyopathy (HCM).

Methods and results

105 patients with HCM and 20 healthy subjects underwent CMR. In patients with HCM, TAPSE_in (r = 0.31, p = 0.001) and RVFS (r = 0.35, p = 0.0002) revealed a significant but weak correlation with right ventricular ejection fraction (RVEF), whereas TAPSE_out (r = 0.57, p < 0.0001) showed a moderate correlation with RVEF. The ability to predict RVEF < 45 % in HCM patients was best for TAPSE_out. In patients with hypertrophic obstructive cardiomyopathy (HOCM), RVEF showed a significant but weak correlation with TAPSE_out (r = 0.36, p = 0.02) and no correlation with TAPSE_in (r = 0.05, p = 0.07) and RVFS (r = 0.02, p = 0.2). In patients with hypertrophic non-obstructive cardiomyopathy (HNCM), there was a moderate correlation between RVEF and TAPSE_out (r = 0.57, p < 0.0001) and a weak correlation with TAPSE_in (r = 0.39, p = 0.001) and RVFS (r = 0.38, p = 0.002). In the 20 healthy controls, there was a strong correlation between RVEF and all semi-quantitative measurements.

Conclusion

CMR-derived TAPSE_in is not suitable to determine right ventricular function in HCM patients. TAPSE_out showed a good correlation with RVEF in HNCM patients but only a weak correlation in HOCM patients. TAPSE_out might be used for screening but the detection of subtle changes in RV function requires the 3D volumetric approach.     

Protective effects of indomethacin and dexamethasone in a goat model with intrauterine balloon aortic valvuloplasty

Background

Intrauterine balloon aortic valvuloplasty (IUBAV) has been used for critical aortic stenosis. However, it is necessary to determine the fetal impairments such as preterm birth after this approach and to find a way to prevent or reduce them.

Methods

In the present study, we evaluated the therapeutic value of indomethacin (IDM) and dexamethasone (DXS) on reducing the preterm birth rate in experimental goats after IUBAV.

Results

Our results indicated that the administration of IDM/DXS significantly reduced the rate of premature birth. IDM/DXS treatment led to preservation of myocardial ultrastructure with less damage, and amelioration of the fetal and placental circulation. Furthermore, we found that norepinephrine (NE) level was positively associated with the degree of myocardial damage. IDM/DXS administration led to a significant decrease of operation-induced increase of NE levels, which may be associated with the protective effects of IDM/DXS. Lastly, we found that the administration of IDM/DXS did not induce the risk of ductus arteriosus closure or slow down fetal growth.

Conclusions

Our results indicate that IDM/DXS promotes a better gestational outcome at least partially by reducing stress response during and after the operation of IUBAV in the goat model. IDM/DXS may be a useful application in human patients during IUBAV intervention.     

Radiofrequency ablation of premature ventricular contractions originating from uncommon sites of right ventricle

Premature Ventricular Contraction (PVC)/ventricular tachycardia (VT) with left bundle branch block (LBBB) morphology and inferior axis has been described classically to originate from the right ventricular outflow tract (RVOT). Some uncommon sites of idiopathic ventricular arrhythmia (VA) origins have been revealed including tricuspid annulus (TA) and right ventricular (RV) inflow free wall region. We present a series of two cases who have undergone electrophysiological study and successful radiofrequency ablation of frequent monomorphic PVCs with LBBB pattern originating from relatively uncommon sites of RV – TA and RV inflow free wall region.