Reoperation of the Aortic Valve in Octogenarians

The Transcatheter Tricuspid Valve-in-Valve Technique in Degenerated Bioprostheses Without Fluoroscopic Radiopaque Landmarks

Nonetheless, in principle, bioprosthetic heart valves are often preferred to mechanical valves in that not only do they obviate the need for high-level systemic anticoagulation and the attendant bleeding risks, but also higher rates of prosthetic valve thrombosis have been reported observed in the tricuspid position. The transcatheter tricuspid valve-in-valve (TVIV) procedure has expanded the horizons of cardiac surgery by allowing the implantation of stent-valves within degenerated bioprostheses in older adults and even young patients as the reported rate of the mortality of redo surgery in antecedent studies is at least 37%. Fluoroscopic guidance can assist the operator in implanting a bioprosthetic valve by radiopaque findings in the ideal position and depth; nonetheless, the complete radiolucency of some bioprosthetic valves represents a significant hurdle. In this state-of-the-art manuscript, we decided to deeply explain the appropriate heart-team approach in this scenario.

How to treat severe symptomatic structural valve deterioration of aortic surgical bioprosthesis: transcatheter valve-in-valve implantation or redo valve surgery?

The optimal management of aortic surgical bioprosthesis presenting with severe symptomatic structural valve deterioration is currently a matter of debate. Over the past 20 years, the number of implanted bioprostheses worldwide has been rapidly increasing at the expense of mechanical prostheses. A large proportion of patients, however, will require intervention for bioprosthesis structural valve deterioration. Current options for older patients who often have severe comorbidities include either transcatheter valve-in-valve (TVIV) implantation or redo valve surgery. The emergence of TVIV implantation, which is perceived to be less invasive than redo valve surgery, offers an effective alternative to surgery for these patients with proven safety and efficacy in high-risk patient groups including elderly and frail patients. A potential caveat to this strategy is that results of long-term follow-up after TVIV implantation are limited. Redo surgery is sometimes preferable, especially for young patients with a smaller-sized aortic bioprosthesis. With the emergence of TVIV implantation and the long experience of redo valve surgery, we currently have 2 complementary treatment modalities, allowing a tailor-made and patient-orientated intervention. In the heart team, the decision-making should be based on several factors including type of bioprosthesis failure, age, comorbidities, operative risk, anatomical factors, anticipated risks and benefits of each alternative, patient's choice and local experience. The aim of this review is to provide a framework for individualized optimal treatment strategies in patients with failed aortic surgical bioprosthesis.

Multiple-Step Injection Molding for Fibrin-Based Tissue-Engineered Heart Valves

Heart valves are elaborate and highly heterogeneous structures of the circulatory system. Despite the well accepted relationship between the structural and mechanical anisotropy and the optimal function of the valves, most approaches to create tissue-engineered heart valves (TEHVs) do not try to mimic this complexity and rely on one homogenous combination of cells and materials for the whole construct. The aim of this study was to establish an easy and versatile method to introduce spatial diversity into a heart valve fibrin scaffold. We developed a multiple-step injection molding process that enables the fabrication of TEHVs with heterogeneous composition (cell/scaffold material) of wall and leaflets without the need of gluing or suturing components together, with the leaflets firmly connected to the wall. The integrity of the valves and their functionality was proved by either opening/closing cycles in a bioreactor (proof of principle without cells) or with continuous stimulation over 2 weeks. We demonstrated the potential of the method by the two-step molding of the wall and the leaflets containing different cell lines. Immunohistology after stimulation confirmed tissue formation and demonstrated the localization of the different cell types. Furthermore, we showed the proof of principle fabrication of valves using different materials for wall (fibrin) and leaflets (hybrid gel of fibrin/elastin-like recombinamer) and with layered leaflets. The method is easy to implement, does not require special facilities, and can be reproduced in any tissue-engineering lab. While it has been demonstrated here with fibrin, it can easily be extended to other hydrogels.

Tissue-engineered fibrin-based heart valve with a tubular leaflet design

The general approach in heart valve tissue engineering is to mimic the shape of the native valve in the attempt to recreate the natural haemodynamics. In this article, we report the fabrication of the first tissue-engineered heart valve (TEHV) based on a tubular leaflet design, where the function of the leaflets of semilunar heart valves is performed by a simple tubular construct sutured along a circumferential line at the root and at three single points at the sinotubular junction. The tubular design is a recent development in pericardial (nonviable) bioprostheses, which has attracted interest because of the simplicity of the construction and the reliability of the implantation technique. Here we push the potential of the concept further from the fabrication and material point of view to realize the tube-in-tube valve: an autologous, living HV with remodelling and growing capability, physiological haemocompatibility, simple to construct and fast to implant. We developed two different fabrication/conditioning procedures and produced fibrin-based constructs embedding cells from the ovine umbilical cord artery according to the two different approaches. Tissue formation was confirmed by histology and immunohistology. The design of the tube-in-tube foresees the possibility of using a textile coscaffold (here demonstrated with a warp-knitted mesh) to achieve enhanced mechanical properties in vision of implantation in the aortic position. The tube-in-tube represents an attractive alternative to the conventional design of TEHVs aiming at reproducing the valvular geometry.

Valve-in-Valve Implantation of Medtronic CoreValve Prosthesis in Patients with Failing Bioprosthetic Aortic Valves

Background—

Transcatheter aortic valve implantation (TAVI) using the Medtronic CoreValve (MCV) system might represent an alternative to conventional redo surgery in older high-risk patients with a failing aortic valve bioprosthesis.

Methods and Results—

Symptomatic patients with failing aortic valve bioprosthesis, aged ≥65 years with a logistic EuroSCORE ≥10 % were considered for treatment. Local anesthesia was used to retrogradely implant the MCV system into the failing bioprosthetic valve. Clinical events were recorded and a transthoracic echocardiography was performed to evaluate the impact of MCV on hemodynamics after transcatheter aortic valve implantation. A total of 27 patients (aged 74.8±8 years, logistic EuroSCORE of 31±17%) were treated. In those with AS and AS and AR (n=25), the mean gradient declined from 42±16 mm Hg before to 18±8 mm Hg after MCV implantation ( P <0.001), in those with AR the level declined by 2. There was no intraprocedural death and no procedural myocardial infarction. On the basis of the definitions of the Valvular Academic Research Consortium, the rate of major stroke was 7.4 %, of life-threatening bleeding 7.4%, of kidney failure stage III 7.4%, and of major access site complication 11.1 %, respectively. Within 30 days after the procedure, 2 patients died; 1 from stroke and 1 from cardiac failure (30-day mortality: 7.4%).

Conclusions—

These results suggest that transfemoral MCV implantation into a wide range of degenerated aortic bioprosthetic valves—irrespective of the failure mode—is feasible, safe, and improves hemodynamics in older patients with higher risk for conventional aortic valve redo surgery.

Short- and mid-term safety and effectiveness of transcatheter aortic valve implantation in a failing surgical aortic bioprosthesis

OBJECTIVES

The feasibility of transcatheter aortic valve implantation (TAVI) in patients with a failing surgical aortic bioprosthesis has been reported from single centres. We present results from a multi-centre feasibility study in such patients followed for 1 year after TAVI.

METHODS

This study evaluated 18 patients undergoing implantation with the 18-Fr CoreValve TAVI prosthesis in a failing surgical aortic bioprosthesis at three centres in Germany. Subject inclusion requirements included ≥ 75 years old and either surgical risk with logistic European System for Cardiac Operative Risk Evaluation ≥ 15% or ≥ 1 high-risk co-morbidity.

RESULTS

Implanted subjects were 79 ± 4 years old, 67% males, 78% NYHA Class III/IV, with logistic EuroSCORE 34 ± 14, and had failed surgical bioprostheses from six manufacturers. The procedure was considered technically successful in 94% (17/18) of cases. One subject was converted to surgery during the procedure. Mortality at 30 days and 1 year was 11% (2/18) and 28% (5/18), respectively. Two cardiac deaths occurred, including 1 within 30 days. Two subjects had strokes, both within 30 days. After 30 days and 1 year, respectively, 86 and 73% of subjects improved at least 1 NYHA class and the remainder had no change. No aortic regurgitation was reported beyond mild (Grade 1) at 6- and 12-month follow-up.

CONCLUSIONS

Most patients with a failing aortic surgical bioprosthesis were successfully implanted with a TAVI prosthesis in this multi-centre feasibility study. Outcomes at 30 days were within expectations for this very high-risk subgroup and improvements were sustained through 12 months.

Transarterial Medtronic CoreValve System Implantation for Degenerated Surgically Implanted Aortic Prostheses

Background—

To assess the results of transcatheter aortic valve implantation (TAVI) using the Medtronic CoreValve System (MCS), through the transarterial approach, in high-risk patients with degenerated surgically implanted aortic bioprostheses (SP).

Methods and Results—

Of 241 patients who underwent TAVI, 10 (4%) had a degenerated SP. The approach was percutaneous transfemoral in 9 cases and surgical transaxillary in 1. Patients were age 75±10 years of age. All were in New York Heart Association classes III or IV and at high risk for repeated surgery. Seven patients had stented, 2 stentless, and 1 homograft SP. The failure mode was predominant regurgitation in 7 cases and stenosis (aortic valve area, 0.7±0.2 cm 2 ; mean gradient, 58±16 mm Hg) in 3. Based on the echographic measurements, 8 patients received a 26-mm, and 2 a 29-mm-diameter MCS. Procedural success rate was 100%. There was 1 in-hospital death, 1 stroke with moderate sequelae, and 1 pacemaker implantation. There were no other adverse events at 30 days. The mean postimplantation transprosthetic gradient was 13±7 mm Hg; periprosthetic regurgitation was absent or trivial in 9 cases and grade 2 in 1. After a median follow-up of 5 months, there were no additional adverse events. All but 1 of the hospital survivors were in New York Heart Association classes I or II.

Conclusions—

These results suggest that transarterial MCS implantation in degenerated SP is feasible and may lead to hemodynamic and clinical improvement in patients who are poor candidates for repeated surgery, pending confirmation in larger series with longer follow-up.

Transcatheter valve-in-valve implantation for failing bioprosthetic valves

Transcatheter valve implantation is becoming an alternative to conventional surgical valve replacement in patients at high surgical risk. While experience and acceptance with transcatheter techniques increased rapidly, transcatheter valve implantation within failing bioprostheses has emerged as a new concept (valve-in-valve implantation). Currently, the majority of prostheses implanted in patients are bioprosthetic valves that are expected to degenerate over time. Valve-in-valve implantation provides great utility in high-operative-risk patients since the mortality risk for reoperation can be significantly higher than for first-time isolated valve replacement. Although two current devices are CE Mark approved in Europe for implantation within native valves, off-label clinical implementation of valve-in-valve have been described in numerous case reports. In this article, we provide an overview of transcatheter valve implantation in failing bioprostheses with an emphasis on the aortic position.

Simultaneous aortic and mitral valve replacement in octogenarians: a viable option?

BACKGROUND

Few reliable data are available on clinical outcome of octogenarians undergoing simultaneous aortic and mitral valve replacement.

METHODS

We performed a retrospective analysis of 55 patients aged 80 years and over with double valve replacement who were operated on at our institution between 2001 and 2005. Thirty-day mortality and 1-year survival were assessed.

RESULTS

For most of the patients, stenosis was the cause of aortic valve surgery, whereas regurgitation was the cause of mitral valve replacement in the majority of patients. In one third of the patients, cardiac surgery had to be performed on an urgent/emergency basis. A large number of patients had concomitant diagnoses such as atrial fibrillation (73%), coronary artery disease (44%), renal insufficiency (29%), chronic obstructive pulmonary disease (20%), and diabetes mellitus (15%). In total, 16 patients (29%) died during follow-up. Survival rates at 30 days and 1 year were 91% and 71%, respectively. As determined by multivariable logistic regression analysis, Karnofsky performance status (hazard ratio: 0.899 per % increase; 95% confidence interval: 0.811 to 0.996; p = 0.043) and bypass time (hazard ratio: 1.062 per min; 95% confidence interval: 1.006 to 1.120; p = 0.028) were independent predictors of 30-day mortality. Beside these factors, additional independent predictors of 1-year mortality were preoperative stroke and postoperative intestinal failure (p = 0.008 and 0.003, respectively).

CONCLUSIONS

Our data demonstrate that, for selected octogenarians, double valve replacement can be performed with acceptable outcome. A better performance status of the patients at the time of cardiac surgery will probably improve 1-year survival.

Optimum management of elderly patients with calcified aortic stenosis

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.

International normalized ratio self-management lowers the risk of thromboembolic events after prosthetic heart valve replacement

BACKGROUND

Although prosthetic valves are durable and easy to implant, the need for lifetime warfarin-based anticoagulation restricts their exclusive usage. We investigated if anticoagulation self-management improves outcome in a single-center series.

METHODS

Between 1994 and 1998, 765 patients with prosthetic valve replacements were prospectively enrolled and randomized to receive conventional anticoagulation management by their primary physician (group 1, n = 295) or to pursue anticoagulation self-management (group 2, n = 470). A study head office was implemented to coordinate and monitor anticoagulation protocols, international normalized ratios (INR), and adverse events. Patients were instructed on how to obtain and test their own blood samples and to adjust warfarin dosages according to the measured INR (target range, 2.5 to 4).

RESULTS

Mean INR values were slightly yet significantly smaller in group 1 than in group 2 (2.8 +/- 0.7 vs 3.0 +/- .6, p < 0.001). Moreover, INR values of patients with conventional INR management were frequently measured outside the INR target range, whereas those with anticoagulation self-management mostly remained within the range (35% vs 21%, p < 0.001). In addition, the scatter of INR values was smaller if self-managed. Freedom from thromboembolism at 3, 12, and 24 months, respectively, was 99%, 95%, and 91% in group 1 compared with 99%, 98%, and 96% in group 2 (p = 0.008). Bleeding events were similar in both groups. Time-related multivariate analysis identified INR self-management and higher INR as independent predictors for better outcome.

CONCLUSIONS

Anticoagulation self-management can improve INR profiles up to 2 years after prosthetic valve replacement and reduce adverse events. Current indications of prosthetic rather than biologic valve implantations may be extended if the benefit of INR self-management is shown by future studies with longer follow-up.

Valve-in-a-valve concept for transcatheter minimally invasive repeat xenograft implantation

OBJECTIVES

This study sought to evaluate the feasibility of minimally invasive transapical repeat valve-in-a-valve (VinV) implantation.

BACKGROUND

Reoperative heart valve replacement for degenerated xenografts is associated with an increased surgical risk.

METHODS

Conventional Carpentier Edwards porcine aortic (n = 5) and mitral (n = 2) valve prostheses were implanted in 7 pigs. Transapical VinV implantation of a pericardial xenograft fixed within a 23-mm stainless steel, balloon expandable stent (Cribier Edwards, Edwards Lifesciences, Irvine, California) was then performed under fluoroscopic and echocardiographic visualization on the beating heart with ventricular unloading via cardiopulmonary bypass and rapid ventricular pacing.

RESULTS

Valve deployment was successfully performed in all cases. The radiopaque marking within the stent of the conventional aortic or mitral xenograft allowed for optimal positioning of the stent-delivered valve. All valves were firmly positioned without any migration. There were neither paravalvular nor transvalvular leaks, and good hemodynamic function was observed in all cases. All coronary arteries remained patent. Positioning and function were confirmed by autopsy in all animals.

CONCLUSIONS

The VinV concept is promising for minimally invasive beating heart repeat aortic or mitral valve replacement, using a stent-fixed sutureless prosthesis.

Self-management of oral anticoagulation therapy improves long-term survival in patients with mechanical heart valve replacement

BACKGROUND

The Early Self-Controlled Anticoagulation Trial has demonstrated that in patients with mechanical heart valve replacement self-management of oral anticoagulation results in less major thromboembolic events than conventional measurement by the general practitioner. However, the effects of self-management on long-term survival are currently not known.

METHODS

Nine hundred thirty patients participated in a follow-up study of the aforementioned trial (488 from the self-management group and 442 from the conventional group). Long-term survival was assessed 12 years after the study began using the intent-to treat analysis as well as the per protocol analysis. Univariate and multivariate analyses were performed in order to assess independent predictors of survival.

RESULTS

In total, the 930 patients accrued 8,315 patient-years of observation. During follow-up, 236 patients died. According to the intent-to treat analysis, 10-year survival was 76.1% in the conventional group and 84.5% in the self-management group. The corresponding values for the per protocol analysis were 67.7% and 80.6%, respectively. Age, kind of valve surgery, and study group were independent predictors of survival. Self-management of oral anticoagulation increased long-term survival by 23% (intent-to-treat analysis) and 33% (per protocol analysis), respectively, compared with conventional measurement by the general practitioner. Possible reasons for these advantageous results in the self-management group are fewer thromboembolic events due to a higher percentage of international normalized ratio values lying in the target range compared with the conventional group.

CONCLUSIONS

Data indicate that self-management of oral anticoagulation is a promising strategy in order to increase long-term survival in patients with mechanical prosthetic valves.