Current and new-generation transcatheter aortic valve devices: an update on emerging technologies

Transcatheter aortic valve implantation (TAVI) has become an accepted treatment option for patients with symptomatic severe aortic stenosis who are at high risk for traditional surgical aortic valve replacement. In particular, TAVI has been shown to reduce mortality in a randomized comparison with medical treatment and to be non-inferior to surgical aortic valve replacement in ‘high-risk operable’ patients. From its early stages it became apparent that TAVI has tremendous potential and thus considerable efforts were made to design new devices and advance valve technology in order to improve outcomes and increase TAVI applications in complex anatomies and in patients with multiple co-morbidities. In this review, we present the advances in transcatheter aortic valve technology and discuss the current evidence on the new-generation TAVI devices.     

The current status of transcutaneous aortic valve implantation

Transcatheter aortic valve implantation (TAVI) is a relatively novel procedure first performed in 2002 and has undergone rapid development since then. Its main indication is treatment of severe symptomatic aortic valve stenosis. Initially, the procedure was indicated for very sick patients who were not eligible for surgical aortic valve replacement. However, rapid development of the technology and operator skill required for TAVI allowed widening of the indications for its use. Currently, there is evidence that TAVI could be better than the surgical intervention in a broad population and not only in the most sick. This paper reviews the medical literature regarding TAVI, including the relevant medical equipment, different modes of its deployment, main complications of the procedure, main indications and contraindications, and the outcome of the patients who undergo it.     

Transcatheter aortic valve implantation: technique,complications and perspectives

Transcatheter aortic valve implantation (TAVI) has become the preferred treatment option for patients with symptomatic severe aortic stenosis who are inoperable or at high risk for surgical aortic valve replacement. TAVI has shown a clear mortality benefit compared to conservative treatment in inoperable patients, and is at least non-inferior to surgical aortic valve replacement in high-risk operable patients. Through improvements in the field of imaging, refinement in valve technologies, increasing operator and team experience and continuous valuable research, TAVI has developed rapidly in the past years and is expected to further boost in the near future. In this review, we discuss the technical and procedural aspects of TAVI, the acute and late outcomes, and highlight the current expectations and potential future development of this rapidly evolving technology.     

Review on balloon aortic valvuloplasty: a surgeon’s perspective in 2008

The article by Sack and co-workers published in this issue presents the results of a retrospective study on the treatment of severe calcified aortic stenosis (AS) by means of balloon aortic valvuloplasty (BAV) in the elderly patient. While arguing that BAV should be used in patients unfit for surgical aortic valve replacement (AVR) due to relative contraindications their results reveal widely unfavourable outcomes particularly with regard to survival and mortality rates. In contrast, surgical AVR yields excellent results in the mid- and long-term follow-up even in a high-risk patient population. In the rare case of real contraindications to surgical AVR transcatheter valve implantation techniques seem to be the more adequate alternative today.     

Transcatheter aortic valve replacement: the changing paradigm of aortic stenosis treatment

Aortic stenosis is the most common cause for valvular surgery in the USA. For nearly 50 years, surgical aortic valve replacement has been the standard of care for symptomatic patients; unfortunately, a significant number of patients are not referred to surgery owing to advanced comorbidities and age. Transcatheter aortic valve replacement has emerged as an effective therapy for patients at high risk for surgery. Through device innovations and accumulated experience, the safety and efficacy of the procedure has improved since its inception. Transcatheter valve replacement has been found superior to medical therapy in inoperable patients with aortic stenosis, yet many questions remain as to which patients are appropriate for this exciting and novel therapy.     

Recent advances in transcatheter aortic valve replacement for high-risk patients

Aortic stenosis is the most common valvular heart disease of old age. Patients with severe aortic stenosis who develop symptoms have a very poor prognosis without valve intervention. Surgical aortic valve replacement has historically been the only treatment option for these patients. However a significant minority are considered inoperable or at high surgical risk and therefore are refused or decline surgery. In recent years, transcatheter aortic valve replacement has emerged as an alternative treatment option in these high-risk patients. The aim of this review is to summarize the current role of transcatheter aortic valve replacement in contemporary clinical practice including recent advances in technological and procedural aspects and then discuss future directions.     

Balloon valvuloplasty of aortic valve stenosis in childhood: early and medium term results

BACKGROUND: Isolated aortic valve stenosis in childhood is treated by balloon valvuloplasty. The role of independent risk factors for the outcome remains unclear. MATERIAL AND METHODS: We analysed the early and medium term outcome of balloon valvuloplasty in isolated aortic valve stenosis in 44 pediatric patients with isolated, severe aortic valve stenosis at an age younger than 18 years, who received a primary balloon valvuloplasty during the last 5 years in our institution. We evaluated the type of aortic valve morphology, age, clinical status, and myocardial function at the time of the intervention as independent risk factor. RESULTS: A significant early relief of the pressure gradient across the aortic valve (P < 0.001) after balloon valvuloplasty was found. This was independent of the aortic valve morphology. Two neonates with a highly stenotic tricuspid aortic valve and severely compromised haemodynamics died within the first 30 days after the intervention. During medium term follow up (mean 22.5 months) we observed a functional deterioration for the stenosis as well as for the insufficiency of the aortic valve. "Symptoms before intervention" is an independent risk factors (P < 0.001) for valvuloplasty failure. Patients at an "age at intervention 相似文献   

多层螺旋CT在经导管主动脉瓣植入术中的应用

近年来,经导管主动脉瓣植入术（TAVI）为临床治疗外科手术禁忌的重度高危主动脉瓣狭窄提供了新的选择。治疗前全方位评估患者心脏和大血管的解剖有助于选择合适的TAVI手术方式、降低手术风险。MSCT具有高时间分辨率、高空间分辨率及单次即可完成大范围覆盖扫描等优点,可为TAVI提供更全面的信息。本文对MSCT在TAVI术前评估及术后随访中的应用予以综述。     

Delayed right coronary ostial obstruction after J-valve deployment in transcatheter aortic valve implantation: A case report

BACKGROUND Aortic stenosis is the most common valve disease in adults.Transcatheter aortic valve implantation(TAVI)is being increasingly applied for intermediate-to lowrisk patients.Here,we describe an uncommon complication of delayed right coronary obstruction in a transapical TAVI case.CASE SUMMARY A 73-year-old woman with a EuroSCORE II of 1.21%underwent transapical TAVI because of severe aortic stenosis.The surgical procedure was uneventful.However,during routine monitoring after valve placement,the patient had a sudden onset of slow heart rate,the systolic blood pressure dropped sharply from 115 to 60 mmHg,and the central venous pressure abruptly increased from 10 to 33 cmH2O.The patient had a poor response to vasoactive agents.Transesophageal echocardiography revealed poor myocardial contractility,and electrocardiography showed a significant depression of ST-segment.Another angiography was performed immediately,which suggested complete obstruction of the right coronary artery.An emergency protocol was initiated.Cardiopulmonary bypass was established immediately.An aortic biological valve replacement under cardiopulmonary bypass was performed.CONCLUSION Perioperative monitoring,early recognition,and diagnosis of obstruction of coronary arteries in TAVI are important.Transesophageal echocardiography is a useful diagnostic and monitoring tool in this situation.Emergency protocols should be established during TAVI.     

Transcatheter treatment approaches for aortic valve disease

Transcatheter aortic valve implantation (TAVI) for the management of symptomatic aortic stenosis has evolved rapidly over the last ten years, to the point where TAVI has recently been established as the standard of care for inoperable patients. With the results of further trials, steady improvements in device design and a greater understanding, it is anticipated that the indications for TAVI will expand to include patients at high risk of complications from surgical aortic valve replacement. As we see the widespread implementation of TAVI programs worldwide, it is timely for a review on the current status of percutaneous transarterial implantation of the aortic valve.     

Small balloon strategy associated with low pacemaker implantation rate after self-expanding transcatheter valve implantation

BACKGROUND: This study aims to investigate whether small balloon aortic valvuloplasty(BAV) reduces the need for permanent pacemaker implantation (PPMI) after transcatheter aortic valveimplantation (TAVI).METHODS: This was a retrospective analysis using data from our local TAVI database. SmallBAV was defined as a small balloon size (=18 mm) pre-dilatation. Normal BAV was defined as aballoon size >18 mm. The primary endpoint was the incidence of new PPMI.RESULTS: Of 99 consecutive TAVI patients, five patients were excluded due to pre-existingpermanent pacemaker. Patients in the small BAV group (n=57) had a signifi cantly lower PPMI ratecompared with the normal BAV group (n=37) (3.5% vs. 18.9%, P=0.026). Moderate or severe aorticvalve regurgitation post-procedure was similar between the small BAV and normal BAV groups (5.3%vs. 8.1%, P=0.480);likewise, the mean aortic gradient post-procedure did not differ significantly(11.5±5.2 mmHg vs. 12.2±7.3 mmHg, 1 mmHg=0.133 kPa, P=0.580) between the groups. Devicesuccess rates were also similar (94.7% vs. 91.8%, P=0.680). In multivariable analysis, small BAV(P=0.027), the ratio of prosthesis diameter to annulus diameter (P=0.048), and mean aortic gradientby echo in the basement (P=0.021) were independent predictors of PPMI.CONCLUSIONS: The small BAV strategy is associated with a low rate of permanentpacemaker implantation after transcatheter self-expanding valve implantation in this single-centerobservational study.     

Recent developments in aortic stenosis

There have been several recent advances in our understanding of aortic stenosis and in its diagnosis and treatment. Aortic stenosis is now most commonly due to a bicuspid valve. Rheumatic aortic stenosis has become much less common and calcific stenosis of valves in the elderly is a rapidly increasing cause. The prognosis of patients with aortic stenosis can be largely determined by their symptoms, with a mean length of survival of 3 to 5 years for patients with angina, 3 years for patients with syncope, and only 12 to 24 months for patients with heart failure. Virtually all symptomatic patients should be operated on, even those with reduced left ventricular function. The risk of sudden death in asymptomatic adults is low, and thus surgery is generally not needed in these cases. Recently, the noninvasive diagnosis of aortic stenosis has improved dramatically with the advent of two-dimensional and Doppler echocardiography. These techniques provide information on the pressure gradient and can even allow accurate estimates of valve area. Cardiac catheterization is still required, however, to determine the anatomy of the coronary arteries prior to surgery since many patients will have concomitant coronary artery disease. The newest development in the treatment of aortic stenosis is catheter balloon valvuloplasty, which is relatively safe and has shown early promise in reducing the pressure gradient across not increased to the normal range and is significantly less than that following aortic valve replacement. The long-term results of balloon valvuloplasty are still being evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)     

Transcatheter aortic valve implantation: role of multimodality cardiac imaging

Current evidence based on more than 8000 high-risk patients with severe aortic stenosis has demonstrated that transcatheter aortic valve implantation (TAVI) is a feasible alternative to surgical aortic valve replacement in selected patients. Despite current promising results on hemodynamic and clinical improvements, there are several unresolved safety issues, such as the frequency of vascular complications, postprocedural paravalvular leak, atrioventricular heart block and stroke. Multimodality cardiac imaging may help to minimize these complications and may play a central role before (optimizing patient selection, selection of appropriate prosthesis size and anticipating the procedural approach), during and after TAVI (evaluating the immediate and long-term procedural results). This article reviews the state-of-the-art TAVI procedures and the role that multimodality cardiac imaging plays before, during and after TAVI.     

Transcatheter aortic valve implantation outcomes: implications for practice

Aortic stenosis is a common valvular pathological finding in older adults. Currently, aortic valve replacement is the gold-standard treatment for severe symptomatic aortic stenosis. However, patients with advanced age and multiple comorbidities carry a significant operative risk. Transcatheter aortic valve implantation (TAVI) was developed with the goal of offering a less invasive alternative to symptomatic high-risk patients with aortic stenosis. Since the first successful TAVI procedure in 2002, TAVI has been used as a treatment option for patients at very high or prohibitive surgical risk in clinical feasibility trials, registries, and in ongoing randomized controlled trials. There are 2 transcatheter valves in widespread clinical application, with several others in different stages of development. This article provides an overview of TAVI outcomes including insertion options, procedural outcomes, morbidity, valve durability, short- to medium-term survival, and quality of life to guide nursing care interventions. Enhancing nurses' knowledge of the risks, benefits, and potential complications of TAVI will empower nurses in their role as patient advocates and educators and improve patient outcomes. Gaps in the current TAVI research literature are identified.     

Percutaneous balloon valvuloplasty

In the technique of percutaneous balloon valvuloplasty, one or more large balloons are inserted percutaneously and then inflated across a stenotic valve to decrease the degree of obstruction. Currently, the procedure is being performed for patients with pulmonic, mitral, or aortic stenosis. The results vary according to the type of valve and the age of the patient. In patients with pulmonic stenosis, balloon valvuloplasty can be performed safely and the results are excellent. Therefore, at many institutions it is the procedure of choice for the treatment of isolated pulmonic stenosis. In patients with mitral stenosis, the results depend on the morphologic features of the stenotic valve. In patients with highly calcified and fibrotic mitral valve leaflets, the risks of the procedure are increased and the results are suboptimal. In experienced hands, however, balloon valvuloplasty is excellent for patients with a pliable, noncalcified mitral valve or those for whom operation imposes an extremely high risk. The use of balloon valvuloplasty for aortic stenosis has been limited to the frail, elderly patient who either is not a surgical candidate or is at high risk for operation. Although mortality and restenosis rates are high on short-term follow-up, aortic balloon valvuloplasty provides palliation of symptoms in many patients who otherwise would have been unable to undergo any intervention. Long-term follow-up is necessary for determining the ultimate role of balloon valvuloplasty in cardiology.     

Palliative percutaneous aortic balloon valvuloplasty before noncardiac operations and invasive diagnostic procedures

Percutaneous aortic balloon valvuloplasty (PABV) is useful in palliating symptoms of severe aortic stenosis in patients who are not candidates for aortic valve replacement. In 15 patients who had severe aortic stenosis and a contraindication to aortic valve replacement, PABV was performed before a noncardiac procedure, in an attempt to improve their hemodynamics and reduce the risks associated with the operation or preoperative diagnostic test. The mean aortic gradient was reduced from 58.1 +/- 6.0 mm Hg to 32.2 +/- 4.0 mm Hg (P less than 0.0002), and the aortic valve area was increased from 0.49 +/- 0.04 cm2 to 0.85 +/- 0.10 cm2 (P less than 0.0002). Complications associated with PABV included left ventricular perforation in three patients (which resulted in death in one of them), transient congestive heart failure in one, and development of femoral pseudoaneurysms in one. After PABV, nine patients underwent the planned surgical procedure under general anesthesia without complications. Five patients underwent surgical diagnostic procedures after PABV that resulted in a change in treatment strategy. Three of these patients required no further treatment, and two required resection of the colon for bleeding, which was preceded by aortic valve replacement. This study demonstrates that PABV may be useful in reducing the risks of noncardiac procedures in selected patients with severe aortic stenosis who are otherwise not candidates for aortic valve replacement.     

超声心动图评价二瓣化主动脉瓣瓣膜功能

目的 探讨超声心动图在二瓣化主动脉瓣病理生理进展评价中的应用,分析二瓣化主动脉瓣各年龄瓣膜病变的程度.方法 回顾性分析135例二瓣化主动脉瓣患者超声资料及病例资料,结合临床资料分析患者病程进展中瓣膜功能的变化.结果 二瓣化主动脉瓣关闭不全最常见,本组资料中为68例(50%),单纯狭窄仅19例(14%).狭窄并关闭不全者29例(22%),瓣膜功能正常者19例(14%).各年龄组内主动脉瓣病变均以关闭不全多见.病程晚期的手术患者各年龄组内主动脉病变亦均以关闭不全为主.结论 超声心动图能对主动脉瓣的病变作出早期诊断.二瓣化主动脉瓣最常见的瓣膜病变是主动脉瓣关闭不全.     

News in Brief

Increased life-expectancy has led to a growing elderly population frequently presenting with aortic stenosis. This review focuses on the pathogenesis of calcific aortic stenosis, diagnosis and possible ways to halt the progression to severe symptomatic aortic stenosis, methods of assessing symptoms and severity, and modalities and timing of aortic valve replacement. At present the treatment of aortic stenosis for the majority of patients is surgical, and any patient with symptomatic severe aortic stenosis should be considered for aortic valve replacement. This article also discusses the role of emerging techniques of closed heart valve implantation either transfemoral or transapical, and which patients might be candidates for these new approaches to the treatment of aortic stenosis in the elderly population.     

自体心包补片修补主动脉瓣环辅助主动脉瓣置换

背景：在主动脉置换过程中常遇到瓣环钙化、瓣周囊肿等特殊情况,这时一般应用特殊技术辅助主动脉瓣置换。目的：观察自体心包补片修补主动脉瓣环辅助主动脉瓣置换治疗钙化性主动脉瓣狭窄并瓣环钙化的临床可行性。方法：回顾性分析2009年1月至2012年1月郑州大学第一附属医院42例钙化性主动脉瓣狭窄并瓣环钙化患者的临床资料,并通过统计学软件处理自体心包补片修补主动脉瓣环技术辅助主动脉瓣置换前后的主动脉瓣有效瓣口面积指数、最大跨瓣压差、血流峰值速度、左室射血分数等数据,分析自体心包补片修补主动脉瓣环技术辅助主动脉瓣置换的应用效果。结果与结论：无置换中死亡病例,置换中主动脉阻断时间为52-88（63.0±18.1）min,体外循环时间为78-122（102.6±25.1）min,置换后1例患者出现急性肾功能衰竭,经床旁血透治疗后治愈。余患者无严重置换并发症。置换后住院天数为7-20（13.6±5.5）d。置换后多普勒超声心动图示：瓣膜功能良好,均未发现主动脉瓣周漏。置换后6个月的主动脉瓣有效瓣口面积指数、最大跨瓣压差、血流峰值速度、左室射血分数均有显著改善,与置换前比较差异均有显著性意义（P〈0.05）。证实对置换适应证合适的特殊换瓣患者,自体心包补片修补主动脉瓣环辅助主动脉瓣置换可取得满意的外科治疗效果,且操作安全简单,是一项可行的技术。     

Revival of an old method with new techniques: balloon aortic valvuloplasty of the calcified aortic stenosis in the elderly

Balloon aortic valvuloplasty (BAV), introduced since almost 20 years, has experienced a revival for its use in the treatment of elderly patients with severe calcified aortic stenosis that are associated with high operative risk and co-morbidities. This is due to the introduction of new balloon catheters and techniques. This study reports about 75 such cases performed within the past 28 months. The mean age of our patient group was 78 +/- 7 years (median = 80 years). Risk calculation with the EuroSCORE demonstrated an average value of 24.4 +/- 19.5%. BAV was performed along with burst pacing to reduce transvalvular blood flow for stabilization of the balloon catheter until blood pressure dropped to less than 50 mmHg. BAV was performed in 72 patients with a procedural success rate of 73%. There was a decrease of 31 mmHg peak-to-peak gradient across the aortic valve from 63 +/- 35 to 32 +/- 22 mmHg (P < 0.0001). Mean gradient was reduced from 51 +/- 24 to 27 +/- 15 mmHg (P < 0.0001). Aortic valve area increased by 49% from 0.84 +/- 0.33 to 1.25 +/- 0.45 cm(2) (P < 0.0001). Serious adverse events (SAE) occurred in 17% of the 75 BAV procedures. Follow-up revealed a significant improvement in 6-month and 1-year survival. The improved technology of BAV makes this technique attractive for elderly patients who are at high operative risk or in cases where valve replacement was refused for any reason.