Carpentier-Edwards Perimount Magna Valve Versus Medtronic Hancock II: A Matched Hemodynamic Comparison

Association of Valve Size and Hemodynamic Performance With Clinical Outcomes in Aortic Valve Replacement - A Long-Term Follow-up in an Asian Population

BACKGROUND

Studies of the influence of smaller body type on the severity of prosthesis-patient mismatch (PPM) after small-sized surgical aortic valve replacement (SAVR) are few, but the issue is particularly relevant for Asian patients.

METHODS AND RESULTS

695 patients who underwent SAVR with bioprosthetic valves had their hemodynamic valve performance analyzed at 3 months, 1 year, 3 years, and 5 years after operation, and clinical outcomes were assessed. The patients were stratified into 3 valve size groups: 19/21, 23, and 25/27 mm. A smaller valve was associated with higher mean pressure gradients at the 4 time points after operation (P trend <0.05). However, the 3 valve size groups demonstrated no significant differences in the risk of clinical events. At none of the time points did patients with projected PPM show increased mean pressure gradients (P>0.05), whereas patients with measured PPM did (P<0.05). Compared with patients with projected PPM, those with measured PPM demonstrated higher rates of infective endocarditis readmission (adjusted hazard ratio [aHR] 3.31, 95% confidence interval [CI] 1.06-10.39) and a higher risk of composite outcomes (aHR 1.45, 95% CI 0.95-2.22, P=0.087).

CONCLUSIONS

Relative to those receiving larger valves, patients receiving small bioprosthetic valves had poorer hemodynamic performance but did not demonstrate differences in clinical events in long-term follow-up.

Excess Reintervention With Mitroflow Prosthesis for Aortic Valve Replacement: Ten-Year Outcomes of a Randomized Trial

BACKGROUND

Current bioprostheses are considered to have improved durability and better hemodynamic performance compared with previous designs, but there are limited comparative data on late outcomes.

METHODS

From 2009 through 2011, 300 adults with severe aortic valve stenosis undergoing aortic valve replacement (AVR) were randomly assigned to receive Edwards Magna, St Jude Epic, or Sorin Mitroflow bioprostheses (n = 100, n = 101, n = 99, respectively). Overall survival was analyzed using Kaplan-Meier and Cox proportional hazards methods, whereas competing risk analysis was used for all time-to-event outcomes. Serial echocardiographic data were fitted with longitudinal models stratified by implant valve size.

RESULTS

During median follow-up of 9.8 years (interquartile range, 8.7-10.2), 10-year survival was 50% for the Magna group, 42% for the Epic group, and 41% for the Mitroflow group (P = .415). Cumulative risk of stroke was 9% at 10 years, and rates were comparable for the three groups. Indexed aortic valve area and mean gradients were similar among the three groups receiving 19 mm and 21 mm valves, but in larger (23 mm or more) prostheses, gradients were lower (P < .001) and indexed aortic valve areas were higher in the Magna group (P < .001). The 10-year risk of endocarditis differed by group (P = .033), with higher incidence in the Mitroflow vs the Magna group (7% vs 0%, P = .019). Late risk of reinterventions in the Mitroflow group was 22%, compared with 0% in the Magna group (P < .001) and 5% in the Epic group (P = .008).

CONCLUSIONS

The Magna valve had the lowest gradients and largest indexed aortic valve area with larger implant sizes. The Mitroflow bioprosthesis is associated with an increased rate of reintervention and possible increased risk of infection compared with Magna and Epic valves.

Structural valve deterioration of bioprosthesis in the aortic position: A single-center experience

BACKGROUND

Aortic valve replacement (AVR) is one of the most common open-heart surgical procedures. The durability of the tissue valve in the aortic position is crucial in AVR and transcatheter AVR. We reviewed structural valve deterioration using echocardiographic follow-up in three types of surgical aortic tissue valves.

METHODS

A retrospective analysis was conducted where hemodynamic deterioration was evaluated and compared using transthoracic echocardiography, including pressure gradients and effective orifice area. Kaplan-Meier analyses were used to summarize the time to failure.

RESULTS

The study included 133 Trifecta, 156 Epic, and 321 Magna Ease valves. Seventy-six percent (1941/2551) of patients had to be excluded due to insufficient echo data. Through univariate analysis, 34% (216/610) of valves met deterioration criteria after 24 months. Unadjusted survival curves showed a significant difference between valves (p ≤ .001), with a longer mean time to deterioration for the Magna Ease versus Trifecta and Epic of 68.9 versus 50.1 and 38.2 months, respectively. A Cox proportional hazard analysis found worse hazard ratios of 1.69 (p ≤ .04) and 2.4 (p ≤ .01) for Trifecta versus Magna and Epic versus Trifecta, respectively.

CONCLUSION

All three valve types demonstrated structural valve deterioration on echocardiographic follow-up with significant differences in rate. The Magna Ease appeared to have the highest durability, and the Epic the lowest. Further investigation is warranted to confirm the results in a larger multicenter study.

A survey of cardiac surgeons to evaluate the use of sutureless aortic valve replacement in Canada

BACKGROUND

Sutureless aortic valve replacement (SuAVR) is gaining popularity for the treatment of aortic stenosis. We aimed to describe Canadian cardiac surgeons' practice patterns and perceptions regarding SuAVR.

METHODS

Content experts (clinicians and methodologists) developed the survey. Domains in the questionnaire include: respondent characteristics, factors influencing the decision to implant a SuAVR, barriers to SuAVR use, and interest in participating in a trial.

RESULTS

A total of 66 cardiac surgeons (median duration of practice: 15 years; range 8-20 years) from 18 hospitals across Canada responded to the survey for a response rate of 84%. Surgeons reported that the following patient characteristics increased the likelihood they would choose SuAVR: hostile root (73%), small annular size (55%), high Society of Thoracic Surgery risk score (42%), older age (40%), to support minimally invasive surgery (25%) and redo-operation (23%). The following patient characteristics made surgeons less likely to pursue SuAVR: young age (73%), low STS score (40%), and large annular size (30%). Reported barriers to SuAVR use included: cost (33%), permanent pacemaker risk (27%) and uncertain durability (12%). Of respondents, 73% were interested in participating in a randomized controlled trial comparing SuAVR with transcatheter aortic valve replacement.

CONCLUSIONS

The primary reasons for surgeons selecting SuAVR were high surgical risk and anatomical challenges. Cost is a primary factor limiting SuAVR use.

Bioprosthesis in the Mitral Position: Bovine Pericardial versus Porcine Xenograft

Background

While the use of bioprosthetic valves for mitral valve replacement (MVR) is increasing, very few studies have compared bovine pericardial and porcine valves in the mitral position to help guide bioprosthetic selection.

Methods

In the present study, patients who underwent MVR using bovine pericardial valves were compared with those who underwent MVR with porcine bioprostheses between January 1996 and July 2018. Those with prior MVR, infective endocarditis, congenital mitral valve disease, or ischemic mitral regurgitation were excluded. The primary outcomes were structural valve deterioration (SVD) and mitral valve reoperation from any cause, and death was regarded as a competing risk. Competing risk analysis and propensity score-matching were used for comparisons.

Results

Among the 388 patients enrolled, pericardial and porcine bioprostheses were implanted in 217 (55.9%) and 171 (44.1%), respectively. Propensity score-matching yielded 122 pairs of patients that were well-balanced for all baseline covariates. No significant differences were observed between the groups in unadjusted (p=0.09) and adjusted overall survival (hazard ratio [HR], 1.13; 95% confidence interval [CI], 0.72–1.76; p=0.60). Competing risk analysis revealed no significant differences in the risks of mitral reoperation (HR, 1.07; 95% CI, 0.50–2.27; p=0.86) and development of SVD (HR, 1.57; 95% CI, 0.56–4.36; p=0.39) between the groups. Matched population analysis confirmed similar results regarding reoperation (HR, 0.99; 95% CI, 0.40–3.22; p=0.98) and SVD (HR, 1.39; 95% CI, 0.41–4.73; p=0.60).

Conclusion

No significant differences in survival or valve durability were observed between bovine pericardial and porcine bioprosthetic MVR. These findings require further validation through studies with larger sample sizes.

Two-Year Clinical Follow-Up Assessment of the Novel Cingular Surgical Bovine Pericardial Valve

Objectives: To evaluate the 2-year clinical safety and hemodynamic outcomes of the Cingular bovine pericardial bioprosthesis. Methods: A prospective, multicenter, single-arm trial was conducted in patients who required aortic or mitral valve replacement. From March 2016 to October 2017, 197 patients were implanted with the Cingular bovine pericardial valve at five sites in China. The clinical outcomes and hemodynamic performance were assessed through a 2-year follow-up. Clinical safety events were reviewed by an independent clinical events committee, and echocardiographic data were assessed by an independent core laboratory. Results: The mean age was 66.9 ± 4.9 years. The 2-year survival rate was 96.4%. A complete 2-year clinical follow-up was achieved in 189 of 190 survivors. No case of structural valve deterioration, major perivalvular leak, prosthetic valve endocarditis, or valve-related reoperation was seen. For the aortic valve, the mean pressure gradient observed was 12.5 ± 4.0 mm Hg, and the effective orifice area (EOA) was 2.0 ± 0.3 cm2. For the smaller size aortic valves, 19 mm and 21 mm, respective mean EOA values of 1.7 ± 0.2 cm2 and 1.8 ± 0.2 cm2 were found. The values for mean pressure gradient and mean EOA for mitral bioprostheses were 4.0 ± 1.4 mm Hg and 2.2 ± 0.3 cm2, respectively. There was no significant change between 1-year and 2-year hemodynamic performance. Conclusions: The Cingular bovine pericardial valve showed favorable clinical safety and hemodynamic outcomes over a 2-year follow-up. Further follow-up is required to validate the long-term durability.

Pericardial Versus Porcine Valves for Surgical Aortic Valve Replacement

Two prototypes of material to constitute surgical bioprosthetic aortic valve (AV) are bovine pericardium and porcine valves. Earlier studies have consistently shown superior hemodynamic profiles in bovine pericardial valves, however, it is not clear whether such superior hemodynamic profiles can be translated into improved clinical outcomes. In patients undergoing isolated bioprosthetic surgical aortic valve replacement (AVR) (636 patients between January 2000 and May 2016), the use of bovine pericardial valves was associated with superior hemodynamic profiles and improved late survival as compared with porcine valves. Freedom from adverse valve-related complication rates were not significantly different between the 2 groups.

Background and Objectives

There still are controversies on which type between bovine pericardial and porcine valves is superior in the setting of aortic valve replacement (AVR). This study aims to compare clinical outcomes of AVR using between pericardial or porcine valves.

Methods

The study involved consecutive 636 patients underwent isolated AVR using stented bioprosthetic valves between January 2000 and May 2016. Of these, pericardial and porcine valves were implanted in 410 (pericardial group) and 226 patients (porcine group), respectively. Clinical outcomes including survival, structural valve deterioration (SVD) and trans-valvular pressure gradient were compared between the groups. To adjust for potential selection bias, inverse probability treatment weighting (IPTW) was conducted.

Results

The mean follow-up duration was 60.1±50.2 months. There were no significant differences in the rates of early mortality (3.1% vs. 3.1%; p=0.81) and SVD (0.3%/patient-year [PY] vs. 0.5%/PY; p=0.33) between groups. After adjustment using IPTW, however, landmark mortality analyses showed a significantly lower late (>8 years) mortality risk in pericardial group over porcine group (hazard ratio [HR], 0.61; 95% confidence interval, [CI] 0.41–0.90; p=0.01) while the risks of SVD were not significantly difference between groups (HR, 0.45; 95% CI, 0.12–1.70; p=0.24). Mean pressure gradient across prosthetic AV was lower in the Pericardial group than the Porcine group at both immediate postoperative point and latest follow-up (p values <0.001).

Conclusions

In patients undergoing bioprosthetic surgical AVR, bovine pericardial valves showed superior results in terms of postoperative hemodynamic profiles and late survival rates over porcine valves.

Comparison of porcine versus bovine pericardial bioprosthesis in the mitral position

BACKGROUND

There are no reports of midterm outcomes after mitral valve replacement with a 25-mm bioprosthesis in a large series of patients. This study aimed to examine perioperative and midterm outcomes of bioprosthetic valve choice, porcine or bovine pericardial, in the mitral position, focusing on 25-mm valves.

METHODS

From 2007 to 2018, 467 patients received a mitral bioprosthesis, with or without concomitant procedures. Of these, 111 (23.8%) were porcine, and 356 (76.2%) were bovine pericardial, and 219 patients (46.9%) received a 25-mm valve. A propensity-matched cohort of 192 patients was used for outcome analyses. The influence of the valve type on midterm survival and incidence of cardiac death was assessed. Similarly, subanalysis stratified by valve size was conducted.

RESULTS

In matched patients, there were no differences in midterm survival and incidence of cardiac death between the two groups (log-rank test; p = .268 and p = .097, respectively). There were no differences in midterm survival and incidence of cardiac death between the 25-mm valve and larger valve (log-rank test; p = .563 and p = .597, respectively). The Cox proportional-hazards model revealed that the valve type and 25-mm valve did not affect midterm survival (p = .487 and p = .375, respectively) and incidence of cardiac death (p = .678 and p = .562, respectively).

CONCLUSIONS

The choice of a porcine or bovine pericardial bioprosthesis does not affect midterm survival and cardiac death. The 25-mm valves, whether bovine or porcine, could be an appropriate alternative when the patient's body size is small.

Porcine and bovine aortic valve comparison for surgical optimization: A fluid-structure interaction modeling study

BACKGROUND

Porcine aortic valve (PAV) and bovine aortic valve (BAV) are commonly used in aortic valve replacement (AVR) surgeries. A detailed comparison for their hemodynamic and structural stress/strain performances would help to better understand valve cardiac function and select valve type and size for AVR outcome optimizations.

METHODS

Eight fluid-structure interaction models were constructed to compare hemodynamic and stress/strain behaviors of PAV and BAV with 4 sizes (19, 21, 23, and 25 mm). Blood flow velocity, systolic cross-valve pressure gradient (SCVPG), geometric orifice area (GOA), flow shear stresses (FSS), and stress/strain were obtained for comparison.

RESULTS

Compared with PAV, BAV has better hemodynamic performance, with lower maximum flow velocity (7.17%) and pressure (9.82%), smaller pressure gradient (mean and peak SCVPG: 8.92% and 9.28%), larger GOA (9.56%) and lower FSS (6.61%). The averages of the mean and peak net pressure gradient values from 4 BAV models were 8.10% and 8.35% lower than that from PAV models. Larger valve sizes for both PAV and BAV had improved hemodynamic performance. Maximum flow velocity, pressure, mean SCVPG and maximum FSS from 25 mm BAV were 36.80%, 15.81%, 39.05% and 38.83% lower than those from 19 mm BAV. The GOA of PAV and BAV 25 mm Valve were 43.75% and 33.07% larger than 19 mm valves, respectively. BAV has lower stress on the leaflets than PAV.

CONCLUSIONS

BAV had better hemodynamic performance and lower leaflets stress than PAV. More patient studies are needed to validate our findings.

One-year outcome with a bovine pericardial valve

Objectives

To evaluate the safety and effectiveness of a novel surgical bovine pericardial valve for aortic and mitral valve replacements.

Methods

Between March 2016 and October 2017, 197 patients (mean age, 66.9 ± 4.9 years; 40.6% were women) underwent aortic valve replacement and mitral valve replacement and were implanted with the Cingular bovine pericardial valve (Shanghai Cingular Biotech Corporation, Shanghai, China) in a prospective, multicenter, single-arm trial in China. A total of 161 aortic and 49 mitral prostheses were implanted. Patients were followed up to 1 year. The primary end point was the 1-year overall rate of valve-related complications, including thromboembolic event, valve thrombosis, major hemorrhage event, major perivalvular leak, and prosthetic valve endocarditis.

Results

The 1-year overall rate of valve-related complications was 0.5% (95% confidence interval, 0.1%-3.7%). The 1-year survival was 96.4%. The mean gradient and effective orifice area for aortic prostheses at 1 year postoperatively were 12.8 ± 4.4 mm Hg and 1.9 ± 0.3 cm², respectively. Particularly, the mean gradients and effective orifice area for 19 mm and 21 mm sizes of aortic prostheses at 1 year were 17.0 ± 3.8 mm Hg and 1.6 ± 0.2 cm², 13.1 ± 4.0 mm Hg and 1.8 ± 0.1 cm², respectively. Patient–prosthesis mismatch occurred in only 1.3% patients for aortic valve implantation at 1 month. No structural valve deterioration and no endocarditis occurred.

Conclusions

The Cingular bovine pericardial valve was safe and effective for surgical aortic and mitral valve replacement. The 1-year rate of valve-related complications was very low. Early hemodynamic performance was excellent even for the small aortic root.

Rapid Deployment Aortic Valves Deliver Superior Hemodynamic Performance In Vitro

OBJECTIVE

Clinical studies have demonstrated excellent hemodynamic performance of rapid deployment aortic valves; however, few studies have directly compared the performance of these valves with conventional bioprosthetic valves. Thus, the hemodynamic function of the EDWARDS INTUITY valve (rapid deployment valve) was compared with the Edwards Magna Ease valve in vitro (Edwards Lifesciences Corp, Irvine, CA USA).

METHODS

Elastomeric material was used to create an aortic root model that included a left ventricular outflow tract and aortic annulus. The model was based on reconstructions from 3-dimensional multislice computed tomography images in patients with aortic stenosis; the aortic root was scaled to a 21-mm effective annulus diameter. EDWARDS INTUITY valves (21-mm diameter) were deployed by stent frame expansion within the aortic root; Edwards Magna Ease valves (21-mm diameter) were sutured to the annulus. The left ventricular outflow tract area index (left ventricular outflow tract area/baseline area) and ellipticity or noncircularity as indexed by Dmax/Dmin were measured under a video microscope after valve placement. Hemodynamic data were collected under pulsatile flow with saline (70 beats per minute, 5 L/min, 100 mm Hg aortic pressure).

RESULTS

Compared with the Edwards Magna Ease valve (n = 4), the EDWARDS INTUITY valve (n = 4) had a greater effective orifice area (1.56 ± 0.01 vs 1.85 ± 0.06 cm, P < 0.001) and a lower transvalvular pressure gradient (23.4 ± 0.51 vs 16.8 ± 1.3 mm Hg, P < 0.001). Multiple regression analysis showed that 93% of the variation in the effective orifice area and transvalvular pressure gradient was due to variation in the left ventricular outflow tract area index and ellipticity index.

CONCLUSIONS

A clinically relevant aortic root model was developed to evaluate aortic valve performance. The superior performance of the EDWARDS INTUITY valve seemed to be related to both a greater inflow area and a more circular left ventricular outflow tract.

Surgical Enlargement of the Aortic Root Does Not Increase the Operative Risk of Aortic Valve Replacement

Background:

Surgical aortic root enlargement (ARE) during aortic valve replacement (AVR) allows for larger prosthesis implantation and may be an important adjunct to surgical AVR in the transcatheter valve-in-valve era. The incremental operative risk of adding ARE to AVR has not been established. We aimed to evaluate the early outcomes of patients undergoing AVR with or without ARE.

Methods:

From January 1990 to August 2014, 7039 patients underwent AVR (AVR+ARE, n=1854; AVR, n=5185) at a single institution. Patients with aortic dissection and active endocarditis were excluded. Mean age was 65±14 years and 63% were male. Logistic regression and propensity score matching were used to adjust for unbalanced variables in group comparisons.

Results:

Patients undergoing AVR+ARE were more likely to be female (46% versus 34%, P <0.001) and had higher rates of previous cardiac surgery (18% versus 12%, P <0.001), chronic obstructive pulmonary disease (5% versus 3%, P =0.004), urgent/emergent status (6% versus 4%, P =0.01), and worse New York Heart Association status ( P <0.001). Most patients received bioprosthetic valves (AVR+ARE: 73.4% versus AVR: 73.3%, P =0.98) and also underwent concomitant cardiac procedures (AVR+ARE: 68% versus AVR: 67%, P =0.31). Mean prosthesis size implanted was slightly smaller in patients requiring AVR+ARE versus AVR (23.4±2.1 versus 24.1±2.3, P <0.001). In-hospital mortality was higher after AVR+ARE (4.3% versus 3.0%, P =0.008), although when the cohort was restricted to patients undergoing isolated aortic valve replacement with or without root enlargement, mortality was not statistically different (AVR+ARE: 1.7% versus AVR: 1.1%, P =0.29). After adjustment for baseline characteristics, AVR+ARE was not associated with an increased risk of in-hospital mortality when compared with AVR (odds ratio, 1.03; 95% confidence interval, 0.75–1.41; P =0.85). Furthermore, AVR+ARE was not associated with an increased risk of postoperative adverse events. Results were similar if propensity matching was used instead of multivariable adjustments for baseline characteristics.

Conclusions:

In the largest analysis to date, ARE was not associated with increased risk of mortality or adverse events. Surgical ARE is a safe adjunct to AVR in the modern era.

Hemodynamics of Pericardial Aortic Valves: Contemporary Stented versus Stentless Valves in a Matched Comparison

PURPOSE

Hemodynamic performance of aortic valve bioprostheses is essential for reliable function and durability. So far, the supra-annularly implanted stentless Sorin Freedom Solo (SFS) demonstrated unsurpassed hemodynamic properties. As contemporary stented and externally mounted pericardial bioprostheses, like the Labcor Dokimos Plus (LDP), also improve hemodynamic performance, these types of valves were compared in this study.

METHODS

A total of 218 patients, who underwent aortic valve replacement with the LDP or the SFS, were matched retrospectively 1:1 on variables affecting hemodynamic measurements: implanted valve size, age, sex, and body surface area (BSA). With matching tolerance for valve size and gender of 0%, for age and BSA of 5%, 57 patient-pairs were yielded. Operative data, clinical, and hemodynamic outcome were analyzed.

RESULTS

Except for slightly higher left ventricular function and lower procedural times in the SFS group, preoperative, operative, and postoperative characteristics of patient-pairs did not differ significantly. Mean pressure gradients, effective orifice areas (EOAs), and indexed EOAs were comparable. Corresponding to valve sizes of 21, 23, 25, and 27 mm, the indexed EOAs of the LDP and SFS prostheses were 1.08 ± 0.33, 0.92 ± 0.19, 0.93 ± 0.24, 0.99 ± 0.13 cm²/m² and 0.81 ± 0.13, 0.92 ± 0.28, 0.95 ± 0.20, 1.04 ± 0.27 cm²/m², respectively.

CONCLUSION

Contemporary stented and stentless pericardial bioprostheses showed excellent hemodynamic properties without significant differences in EOAs and indexed EOAs.

Aortic root stiffness affects the kinematics of bioprosthetic aortic valves

Objectives

In this study, the influence of aortic root distensibility on the haemodynamic parameters and valve kinematics of a bioprosthetic aortic valve was investigated in a controlled in vitro experiment.

Methods

An Edwards INTUITY Elite 21 mm sutureless aortic valve (Edwards Lifesciences, Irvine, CA, USA) was inserted in three transparent aortic root phantoms with different wall thicknesses (0.55, 0.85 and 1.50 mm) mimicking different physiological distensibilities. Haemodynamic measurements were performed in an in vitro flow loop at heart rates of 60, 80 and 100 bpm with corresponding cardiac outputs of 3.5, 4.0 and 5.0 l/min and aortic pressures of 100/60, 120/90 and 145/110 mmHg, respectively. Aortic valve kinematics were assessed using a high-speed camera. The geometric orifice area (GOA) was measured by counting pixels in the lumen of the open aortic valve. The effective orifice area (EOA) was calculated from the root-mean-square value of the systolic aortic valve flow rate and the mean systolic trans-valvular pressure gradient.

Results

The tested aortic root phantoms reproduce physiological distensibilities of healthy individuals in age groups ranging from 40 to 70 years (±10 years). The haemodynamic results show only minor differences between the aortic root phantoms: the trans-valvular pressure gradient tends to increase for stiffer aortic roots, whereas the systolic aortic valve flow rate remains constant. As a consequence, the EOA decreased slightly for less distensible aortic roots. The GOA and the aortic valve opening and closing velocities increase significantly with reduced distensibility for all haemodynamic measurements. The resulting mean systolic flow velocity in the aortic valve orifice is lower for the stiffer aortic root.

Conclusions

Aortic root distensibility may influence GOA and aortic valve kinematics, which affects the mechanical load on the aortic valve cusps. Whether these changes have a significant effect on the onset of structural valve deterioration of bioprosthetic heart valves needs to be further investigated.

Current Clinical Evidence on Rapid Deployment Aortic Valve Replacement: Sutureless Aortic Bioprostheses

Aortic stenosis is the most common valvular heart disease in the Western world. It is caused primarily by age-related degeneration and progressive calcification typically detected in patients 65 years and older. In patients presenting with symptoms of heart failure, the average survival rate is only 2 years without appropriate treatment. Approximately one half of all patients die within the first 2 to 3 years of symptom onset. In addition, the age of the patients presenting for aortic valve replacement (AVR) is increased along with the demographic changes. The Society of Thoracic Surgeons (STS) database shows that the number of patients older than 80 years has increased from 12% to 24% during the past 20 years. At the same time, the percentage of candidates requiring AVR as well as concomitant coronary bypass surgery has increased from 5% to 25%. Surgical AVR continues to be the criterion standard for treatment of aortic stenosis, improving survival and quality of life. Recent advances in prosthetic valve technology, such as transcatheter AVR, have expanded the indication for AVR to the extreme high-risk population, and the most recent surgical innovation, rapid deployment AVR, provides an additional tool to the surgeons’ armamentarium.

Advances in the management of severe aortic stenosis

BACKGROUND

Recent developments in the management of severe aortic stenosis have resulted in a paradigm shift in the way we view the condition. Patients previously denied intervention in the form of surgical aortic valve replacement (SAVR) are now candidates for transcatheter aortic valve implantation and the risk and age profiles of those undergoing SAVR are rising with the ageing population. This review article is designed to provide an overview of developments in the surgical management of severe aortic stenosis. We also discuss the expanding role of minimally invasive surgical approaches to outline the current techniques available to treat patients with severe aortic stenosis.

METHODS

PubMed was searched using the terms 'severe aortic stenosis', 'surgical aortic valve replacement', 'transcatheter aortic valve replacement', 'mechanical aortic valve replacement' and 'sutureless aortic valve replacement'. Selection of articles was based on peer review, journal and relevance. Where possible articles from high-impact factor peer review journals were included.

RESULTS

Minimally invasive operative approaches include mini-sternotomy and mini-thoracotomy. Sutureless aortic prostheses reduce aortic cross-clamp time and cardiopulmonary bypass time; however, long-term follow-up data are unavailable at this time. Mechanical prostheses are advised for those under 60.

CONCLUSION

Multiple advances in the surgical management of aortic stenosis have occured in the past decade. An evolving spectrum of surgical and transcatheter interventions is now available depending on patient age and operative risk.

Hemodynamic performance of Edwards Intuity valve in a compliant aortic root model

Numerous designs of bioprosthetic valves exist. The sutureless surgical valve is a newer design concept which combines elements of the transcatheter valve technology with surgical valves. This design aims at shorter and easier implantation. It was the aim of this study to perform hemodynamic and kinematic measurements for this type of valves to serve as a baseline for following studies which investigate the effect of the aortic root on the valve performance. To this end, the Edwards Intuity aortic valve was investigated in a new in vitro flow loop mimicking the left heart. The valve was implanted in a transparent, compliant aortic root model, and the valve kinematics was investigated using a high speed camera together with synchronized hemodynamic measurements of pressures and flows. The valve closure was asynchronous (one by one leaflet), and the valve started to close before the deceleration of the fluid. The aortic root model showed a dilation of the sinuses which was different to the ascending aorta, and the annulus was found to move towards the left ventricle during diastole and towards the aorta during systole.

The TRIBECA study: (TRI)fecta (B)ioprosthesis (E)valuation versus (C)arpentier Magna-Ease in (A)ortic position

OBJECTIVE

To determine whether the Trifecta bioprosthetic aortic valve produces postoperative haemodynamic results comparable with or better than those of the Magna Ease aortic valve bioprosthesis.

METHODS

We retrospectively reviewed the medical records of patients who had undergone aortic valve replacement with Trifecta or Magna Ease prostheses at eight European institutions between January 2011 and May 2013, and analysed early postoperative haemodynamic performance by means of echocardiography.

RESULTS

A total of 791 patients underwent aortic valve replacement (469 Magna Ease, 322 Trifecta). Haemodynamic variables were evaluated on discharge and during the follow-up (minimum 6 months, maximum 12 months). The mean gradient and the indexed effective orifice area (IEOA) were as follows: 10 mmHg [interquartile range (IQR): 8-13] and 1.10 cm(2)/m(2) (IQR: 0.95-1.27) for Trifecta; 16 mmHg (IQR: 11-22) and 0.96 cm(2)/m(2) (IQR: 0.77-1.13) for Magna Ease (P < 0.001). These significant differences were maintained across all valve sizes. Similar statistically significant differences were found when patients were matched and/or stratified for preoperative characteristics: body-surface area, ejection fraction, mean gradients and valve size. Severe prosthesis-patient mismatch (IEOA: <0.65 cm(2)/m(2)) was detected in 2 patients (0.6%) with Trifecta and 40 patients (8.5%) with Magna Ease (P < 0.001).

CONCLUSIONS

The haemodynamic performance of the Trifecta bioprosthesis was superior to that of the Magna Ease valve across all conventional prosthesis sizes, with almost no incidence of severe patient-prosthesis mismatch. The long-term follow-up is needed to determine whether these significant haemodynamic differences will persist, and influence clinical outcomes.

Comparison of the early haemodynamics of stented pericardial and porcine aortic valves

Data comparing the haemodynamic performance of stented pericardial and porcine aortic valves are conflicting. Hence, we performed a systematic review and meta-analysis comparing the early haemodynamic parameters of stented pericardial and porcine valves in patients undergoing isolated aortic valve replacement. Medline, EMBASE and Web of Science were queried for English language original publications from 2000 to 2013. Studies comparing porcine (PoV) and pericardial (PeV) with regard to their haemodynamic parameters were included in this review. Continuous data were pooled using the mean difference (MD) or the standardized mean difference (SMD). A random-effect inverse weighted analysis was conducted; a P-value<0.05 is considered statistically significant. Results are presented with 95% confidence intervals. Thirteen studies (1265 PeV patients and 871 PoV patients) were included in this analysis. The pooled transvalvular mean gradient was lower for PeV [MD -4.6 (-6.45 to -2.77) mmHg; P<0.01]. Limiting this analysis to small valves (19 and 21 mm; eight studies; 714 patients) revealed that the PeV gradients were significantly lower [MD -4.5 (-5.7 to -3.2); P=0.001]. The corresponding effective orifice area of PeV was significantly larger than PoV [SMD 0.42 (0.15-0.69); P<0.01]. A sensitivity analysis comprising only randomized controlled trials did not significantly alter results. When compared with porcine valves, stented pericardial aortic valves have lower mean transvalvular gradients early after implant. Even pericardial valves in smaller sizes (19 and 21 mm) have a better haemodynamic profile when compared with their counterparts.

Hemodynamic behavior of stentless aortic valves in long term follow-up

OBJECTIVES

Stentless aortic valve replacements show improved hemodynamics due to larger orifice area and lower transvalvular gradients in short and mid-term follow-up. Hemodynamic long-term behavior and the adaptation of the left ventricle as well as valve-durability in patients aged ≤60 years remains unclear.

METHODS

7 to 16 years after aortic valve replacement, 54 patients (mean age at operation 53.1 ± years) received echocardiography and clinical examination. Mean follow-up time was 10.8 ± 2.2 years. Evaluated were NYHA class, transvalvular gradients, estimated aortic valve orifice area, degree of aortic valve insufficiency, left ventricular mass and function.

RESULTS

At follow-up only one patient presented with NYHA class III. All other patients were in NYHA class I or II. Maximum and mean pressure gradients of the prostheses were 16.3 ± 7.4 mmHg and 9.1 ± 4.2 mmHg, respectively. Compared to echocardiography at discharge the mean pressure gradients dropped 18.0% (2.0 ± 0.9 mmHg) and stayed stable until 14 years after the operation. Only 5 patients showed relevant regurgitation (at 13-16 years after valve replacement), 49 showed no or trivial regurgitation. Left ventricular mass had decreased 26.5% (107.9 ± 18.5 g). Left ventricular ejection fraction (LVEF) had increased in most patients and decreased in only one. For patients with preoperatively impaired left ventricular function an increase of LVEF of 13.1 ± 3.1% was seen.

CONCLUSION

Porcine stentless aortic valves provide excellent hemodynamic long-term results without significant rise of transvalvular pressure gradients or relevant insufficiencies until 14 years after implantation, leading to sustained decrease of left ventricular mass and improvement of left ventricular function.

Toward optimization of a novel trileaflet polymeric prosthetic heart valve via device thrombogenicity emulation

Aortic stenosis is the most prevalent and life-threatening form of valvular heart disease. It is primarily treated via open-heart surgical valve replacement with either a tissue or a mechanical prosthetic heart valve (PHV), each prone to degradation and thrombosis, respectively. Polymeric PHVs may be optimized to eliminate these complications, and they may be more suitable for the new transcatheter aortic valve replacement procedure and in devices like the total artificial heart. However, the development of polymer PHVs has been hampered by persistent in vivo calcification, degradation, and thrombosis. To address these issues, we have developed a novel surgically implantable polymer PHV composed of a new thermoset polyolefin called cross-linked poly(styrene-block-isobutylene-block-styrene), or xSIBS, in which key parameters were optimized for superior functionality via our device thrombogenicity emulation methodology. In this parametric study, we compared our homogeneous optimized polcymer PHV to a prior composite polymer PHV and to a benchmark tissue valve. Our results show significantly improved hemodynamics and reduced thrombogenicity in the optimized polymer PHV compared to the other valves. These results indicate that our new design may not require anticoagulants and may be more durable than its predecessor, and validate the improvement, toward optimization, of this novel polymeric PHV design.

Aortic valve replacement: is porcine or bovine valve better?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: 'Is porcine or bovine valve better for aortic valve replacement?' Altogether, 562 papers were found using the reported search, of which 15 represented the best evidence to answer the question. All papers represent either level 1 or 2 evidence. The authors, journal, date, country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. This best evidence paper includes 9880 patients from 1974-2006 to compare both valve types. All studies compared either all or some of the following outcomes: complication, durability, mortality, functional status and haemodynamic function. Ten of 15 papers assessed the complication profile due to aortic valve replacement in both valve types. Four papers concluded that bovine valves are superior, whereas only one favoured porcine valves. Five papers showed a similar complication profile between both valves. Six of 15 papers commented on valve durability. Both porcine and bovine valve groups have two papers each to support their superiority in valve durability. Two papers demonstrated similar durability in both valves. There are 11 papers comparing the postoperative mortality. We suggest that there is no difference in mortality profile as eight papers showed that both valves had similar mortality profiles. Two papers supported bovine valve and one paper supported porcine valve in this aspect. There were four papers assessing the postoperative functional status, with three papers suggesting that both valve types had similar clinical improvement postoperatively. Eleven papers compared the haemodynamic function. Nine papers were in favour of bovine valves. Two papers demonstrated similar haemodynamic profiles in both valves. In conclusion, the bovine valve is superior in its complication and haemodynamic profiles. Both bovine and porcine valves have comparable results with regard to the mortality, postoperative functional status and valve durability. Significant variability between the valve manufacturers, study designs, study period and patient population in the above studies impose limitations to the comparison of both valves.

Aortic valve replacement with the Cardioprotese Premium bovine pericardium bioprosthesis: four-year clinical results

OBJECTIVES

This study reports the initial clinical and echocardiographic results of the Premium bioprosthetic aortic valve up to 4 years of follow-up.

METHODS

Between October 2007 and July 2011, 121 consecutive patients were submitted for aortic valve replacement with the Premium bioprosthetic valve. The mean age was 68 ± 9 years and 64 patients were males. The patients were periodically evaluated by clinical and echocardiographic examinations. The mean follow-up was 21 months (min = 2, max = 48), yielding 217 patients/year for the analysis.

RESULTS

The hospital mortality was 8%. Late survival at 3 years was 89% (95% CI: 81.9-93.3%), and 80% of the patients were in NYHA functional class I/II. The rates of valve-related complications were low, with a linearized incidence of 0.9%/100 patients/year for thromboembolic complications, 0% for haemorrhagic events and 0.9%/100 patients/year of bacterial endocarditis. There was no case of primary structural valve dysfunction. The mean effective orifice area was 1.61 ± 0.45 cm(2); mean gradient 13 ± 5 mmHg and peak gradient 22 ± 9 mmHg. Significant patient-prosthesis mismatch was found in only 11% of the cases.

CONCLUSIONS

The Premium bioprosthetic aortic valve demonstrated very satisfactory clinical and echocardiographic results up to 4 years, similar to other commercially available, third-generation bioprosthetic valves.

Clinical outcomes and hemodynamics of the 19-mm Perimount Magna bioprosthesis in an aortic position: comparison with the 19-mm Medtronic Mosaic Ultra Valve

BACKGROUND

When aortic valve replacement is performed in patients with a small aortic annulus, prosthesis-patient mismatch (PPM) is of concern because it can affect postoperative clinical outcomes. Although larger bioprosthetic valves have been well studied, the hemodynamics of 19-mm bioprostheses have been reported in only a small number of patients. The effectiveness as well as the impact of PPM on outcomes are thus still unclear.

METHODS AND RESULTS

Postoperative clinical and hemodynamic variables were compared in 67 patients with a 19-mm Carpentier Edwards Perimount Magna bioprosthesis and in 10 patients with a 19-mm Medtronic Mosaic Ultra valve. Mean follow-up time was 13 months. There was no in-hospital mortality. Echocardiography 6.5±4.0 months after surgery showed significant decreases in the mean left ventricular (LV)-aortic pressure gradient, and decreases in the mean LV mass index. Reduction in LV mass index did not differ between the valve groups, despite a higher pressure gradient in the Mosaic group. Although PPM was detected in 21 patients in the Magna group, it did not affect regression of the LV mass index during the follow-up period.

CONCLUSIONS

Use of the 19-mm Magna bioprosthesis appears to provide satisfactory clinical results. LV-aortic pressure gradient was lower in the Magna group. The present data suggest that PPM is not related to reduction in the LV mass index.

Thrombogenic potential of Innovia polymer valves versus Carpentier-Edwards Perimount Magna aortic bioprosthetic valves

Trileaflet polymeric prosthetic aortic valves (AVs) produce hemodynamic characteristics akin to the natural AV and may be most suitable for applications such as transcatheter implantation and mechanical circulatory support (MCS) devices. Their success has not yet been realized due to problems of calcification, durability, and thrombosis. We address the latter by comparing the platelet activation rates (PARs) of an improved polymer valve design (Innovia LLC) made from poly(styrene-block-isobutylene-block-styrene) (SIBS) with the commercially available Carpentier-Edwards Perimount Magna Aortic Bioprosthetic Valve. We used our modified prothrombinase platelet activity state (PAS) assay and flow cytometry methods to measure platelet activation of a pair of 19 mm valves mounted inside a pulsatile Berlin left ventricular assist device (LVAD). The PAR of the polymer valve measured with the PAS assay was fivefold lower than that of the tissue valve (p = 0.005) and fourfold lower with flow cytometry measurements (p = 0.007). In vitro hydrodynamic tests showed clinically similar performance of the Innovia and Magna valves. These results demonstrate a significant improvement in thrombogenic performance of the polymer valve compared with our previous study of the former valve design and encourage further development of SIBS for use in heart valve prostheses.

Long-Term Clinical and Hemodynamic Performance of the Hancock II Versus the Perimount Aortic Bioprostheses

Background— The Medtronic Hancock II and the Carpentier-Edwards Perimount are among the world’s most commonly used aortic bioprostheses. However, a direct comparison of their clinical performance is lacking. To minimize biases inherent to between-center comparisons, we examined these prostheses within a large, contemporary, single-center cohort.

Methods and Results— Between 1990 and 2007, 1659 patients (mean age, 73.1±9.3 years) underwent aortic valve replacement with either the Hancock II (N=1021) or the Perimount (N=638). Patients were prospectively followed-up with serial clinic visits and echocardiograms for up to 16 years (mean, 5.0±3.3 years). There was no significant difference in aortic root size preoperatively ( P =0.7). Aortic root enlargement was more commonly performed with the Perimount ( P <0.001), and the manufacturer valve size of the implanted prosthesis was larger with the Hancock II ( P <0.001). Postoperatively, peak and mean transprosthesis gradients were higher for the Hancock II (32.7±0.7 and 16.0±0.3 mm Hg, respectively) than for the Perimount (24.9±0.7 and 13.4±0.4 mm Hg, respectively; P <0.001). However, no difference in left ventricular mass regression was observed at late follow-up ( P =0.9). Unadjusted 10-year survival was 59.4%±2.4% for the Hancock II and 70.2%±3.8% for the Perimount ( P =0.07). Multivariable predictors of survival did not include prosthesis type ( P =0.2).

Conclusions— For the same manufacturer valve size, the Perimount is larger, which may warrant enlarging the aortic root more often, and it is associated with better hemodynamics than the Hancock II. These differences do not impact survival or left ventricular mass regression, and the long-term clinical performances of the Hancock II and Perimount bioprostheses are equivalent.

Thimble type knot pusher: bioprosthesis stents no longer interfere with tying

When a stented bioprosthetic valve is used for aortic valve replacement, the valve stents protruding to the aortic side can interfere with suture tying. To resolve this problem, we developed a novel knot pusher for use on the index finger. This device has a short push rod appropriate for replacing bioprosthetic aortic valve. Surgeons can complete the tying procedure without the help of an assistant.