Biological Aortic Valve Prosthesis Research Articles

Influence of Prosthesis Type on Long-Term Survival after Re-replacement of Aortic Valve Prosthesis

The purpose of this study is to examine the influence of the prosthesis type on early mortality and long-term survival after re-replacement of aortic valve prosthesis, especially in patients over 60 years old. Late outcome of 223 patients who underwent a reoperation on the aortic valve and received a mechanical (mechanical group) or biological (biological group) heart valve prosthesis at a single institution were analyzed for survival and major valve-related complications, including structural valve deterioration, thromboembolism, hemorrhage, further reoperation, and valve-related mortality. Preoperative New York Heart Association class IV (P = 0.001), emergency procedure (P = 0.002), and endocarditis (P = 0.025) were significant risk factors for 30-day mortality rates, which were 8.4 % and 12.5 %, respectively (mechanical versus biological group, P = 0.361). A subanalysis of elective patients revealed a low risk of 30-day mortality of 2.4 % and 1.8 %, respectively. Event-free survival was comparable at 5 years (73.9% ± 3.6% versus 70.5% ± 6.5%, mechanical versus biological group) and 10 year (49.7% ± 5.0% versus 35.3% ± 9.8%, mechanical versus biological group). In a propensity-matched subanalysis, survival and event-free survival were comparable at 5 and 10 years in both groups. The type of aortic valve prosthesis did not affect early outcome and late survival in patients who underwent valve replacement, and therefore, the current strategy favoring a biological aortic valve prosthesis for patients aged over 60 years in first-time operations could also be applied in re-replacement.

Long-Term Safety and Effectiveness of Mechanical Versus Biologic Aortic Valve Prostheses in Older Patients

Background— There is a paucity of long-term data comparing biological versus mechanical aortic valve prostheses in older individuals. Methods and Results— We performed follow-up of patients aged 65 to 80 years undergoing aortic valve replacement with a biological (n=24 410) or mechanical (n=14 789) prosthesis from 1991 to 1999 at 605 centers within the Society of Thoracic Surgeons Adult Cardiac Surgery Database using Medicare inpatient claims (mean, 12.6 years; maximum, 17 years; minimum, 8 years), and outcomes were compared by propensity methods. Among Medicare-linked patients undergoing aortic valve replacement (mean age, 73 years), both reoperation (4.0%) and endocarditis (1.9%) were uncommon to 12 years; however, the risk for other adverse outcomes was high, including death (66.5%), stroke (14.1%), and bleeding (17.9%). Compared with those receiving a mechanical valve, patients given a bioprosthesis had a similar adjusted risk for death (hazard ratio, 1.04; 95% confidence interval, 1.01–1.07), higher risks for reoperation (hazard ratio, 2.55; 95% confidence interval, 2.14–3.03) and endocarditis (hazard ratio, 1.60; 95% confidence interval, 1.31–1.94), and lower risks for stroke (hazard ratio, 0.87; 95% confidence interval, 0.82–0.93) and bleeding (hazard ratio, 0.66; 95% confidence interval, 0.62–0.70). Although these results were generally consistent among patient subgroups, bioprosthesis patients aged 65 to 69 years had a substantially elevated 12-year absolute risk of reoperation (10.5%). Conclusions— Among patients undergoing aortic valve replacement, long-term mortality rates were similar for those who received bioprosthetic versus mechanical valves. Bioprostheses were associated with a higher long-term risk of reoperation and endocarditis but a lower risk of stroke and hemorrhage. These risks varied as a function of a patient’s age and comorbidities.

Results after four years of experience with the new Trifecta™ biological aortic valve prosthesis

Objectives: The Trifecta™ aortic valve prosthesis has been used in clinical studies since 2007. After the market release in 2010 the implant numbers rose quickly. This might be due to the excellent hemodynamic results. However, long term results are missing so far. This study is to present the midterm clinical and echocardiographic results of all patients of a single center who received aortic valve replacement (AVR) with the Trifecta™ prosthesis ± any other concomitant surgery.

Use of transcatheter heart valves for a valve-in-valve implantation in patients with degenerated aortic bioprosthesis: Technical considerations and results

Transcatheter aortic valve implantation has been used to treat high-risk patients with bioprosthetic valve degeneration (valve-in-valve). We report our experience with transcatheter aortic valve implantation in the treatment of degenerated biologic aortic valve prostheses and discuss factors that can influence the outcome. From February 2009 to October 2011, 278 patients underwent transcatheter aortic valve implantation, of whom 23 underwent a valve-in-valve procedure with the Edwards Sapien valve to treat a failing bioprostheses in the aortic position. Eight of these valves were stentless bioprostheses. Thirteen patients had valve failure resulting predominantly from stenosis, and the remaining resulting from regurgitation. Mean age was 76.9 ± 14.4 years. The mean logistic EuroSCORE was 31.8% ± 20.3% and the Society of Thoracic Surgeons score was 7.6% ± 5.4%. All patients were New York Heart Association class III or IV. The majority of the operations (21/23) were performed via the transapical route. Procedural success was 100%, although 1 patient with a degenerated homograft needed immediate placement of a second valve because of low placement of the first. The reduction in the mean gradient was 31.2 ± 17.06 mm Hg to 9.13 ± 4.9 mm Hg. In those patients with predominant aortic regurgitation (9/23), reduction in aortic regurgitation was achieved in all. The median length of stay was 11.7 days (range, 3-44 days). In-hospital and/or 30-day mortality was 0%. Valve-in-valve is a safe and feasible alternative to treat high-risk patients with failing aortic bioprostheses. The early results are excellent, with improvement seen in hemodynamics.

A prospective, randomized comparison of 3 contemporary bioprosthetic aortic valves: Should hemodynamic performance influence device selection?

Latest generation biologic aortic valve prostheses were designed to improve hemodynamic performance. We sought to determine whether there are clinically important early differences among these devices. Three hundred adults with severe aortic valve stenosis undergoing aortic valve replacement were randomized to receive the Edwards Magna, Sorin Mitroflow, or St. Jude Epic bioprostheses (n=100, n=101, n=99, respectively). Early hemodynamic performance was studied by echocardiography. Mean patient age was 76 ± 8 years and there were 203 men (68%). There were no significant differences in baseline characteristics among implant groups. Early mortality was 1.7%, and there were no differences in early adverse events. Postoperative echocardiography showed small but statistically significant differences overall between the Magna, Mitroflow, and Epic valves in mean gradient (14.2 mm Hg, 16.3mm Hg, 16.5 mm Hg, respectively; P=.011), aortic valve area (2.05 cm(2), 1.88 cm(2), 1.86 cm(2), respectively; P=.012), and indexed aortic valve area (1.05 cm(2)/m(2), 0.97 cm(2)/m(2), 0.95 cm(2)/m(2), respectively; P=.012). Prosthetic performance was similar among all with a small (≤21 mm) aortic annulus. Patients who received the Magna device with a 23-mm annulus had slightly greater indexed aortic valve area; those with >23 mm had a slightly lower transprosthetic gradient. Analogous trends were found when data were stratified by either commercial implant size or echocardiography-determined aortic annulus size. Severe patient-prosthesis mismatch was infrequent overall and was similarly low among devices (P value not significant). This prospective, randomized comparison reveals that there are small but consistent early postoperative hemodynamic differences among current third-generation porcine and pericardial aortic valve prostheses. The 3 valves studied performed equally well in patients with a small (≤21 mm) aortic annulus. The Magna valve had a slightly lower mean gradient in those with larger annular size (>23 mm). Longitudinal follow-up of these randomized cohorts is essential to determine late clinical implications of these early postoperative findings.

A supra-annular malposition of the Perceval S sutureless aortic valve: the ‘χ-movement’ removal technique and subsequent reimplantation

The Perceval S sutureless valve prosthesis has recently been introduced as a new biological aortic valve prosthesis, but a specific learning curve is required, as for every cardiac surgical centre dealing with a new technique. After the removal of the stenotic valve, the prosthetic valve is correctly positioned within the mildly decalcified aortic annulus. When a supra-annular malposition occurs, due to an excessively rapid release of the prosthesis in the aorta or incomplete annular visualization, the Perceval S valve can safely be removed even after balloon dilation. The procedure performed is a 'χ-movement' with the aid of anatomical forceps. If the prosthesis does not show any malformation after the procedure, it can be reimplanted in the correct intra-annular position.

Transapical aortic valve implantation after previous aortic valve replacement: Clinical proof of the “valve-in-valve” concept

The "valve-in-valve" concept may be applied in patients with previously implanted biological aortic valve prostheses. There are few reports of individual cases and as yet no clinical proof of safety and feasibility in a larger group of patients. We report the single-center outcome of transapical implantation of aortic valves into degenerated biological aortic valve prostheses ("valve-in-valve") in very high-risk patients. Since October 2008, 14 patients were treated by transapical valve implantation into degenerated biological aortic valve prostheses. Edwards SAPIEN (Edwards Lifesciences, Irvine, Calif) transcatheter heart valves were used in all patients. Mean (± standard deviation) patient age was 73.3 ± 13.1 years. Mean (± standard deviation) Society of Thoracic Surgeons score was 21.9% ± 10.9% (range, 4.2%-42.2%), and logistic euroSCORE was 45.3% ± 22.2%. Preoperatively, all patients were in New York Heart Association functional class III or IV. The procedural success was 100%. Preoperative transthoracic echocardiography mean transvalvular gradient was reduced from 37.1 ± 25.7 mm Hg to 13.1 ± 6.4 mm Hg, and mean aortic valve area increased from 0.68 ± 0.23 cm(2) to 1.35 ± 0.48 cm(2). There was no postoperative valve insufficiency. The postoperative course was short and uneventful in all but 1 patient. One patient underwent reoperation 3 months later because of endocarditis. Up to 20 months postoperatively, the patients were in New York Heart Association functional class I or II. Transapical aortic valve implantation after previous aortic valve replacement was feasible and safe in our patients. The results are excellent with improvements in hemodynamics, but longer follow-up with more patients is needed.

Cerebrovascular Events After Stentless Aortic Valve Replacement During a 9-Year Follow-Up Period

One major advantage of biologic aortic valve prostheses is their low thrombogenicity compared with mechanical prostheses. The purpose of this study was to evaluate the incidence of cerebrovascular events during long-term follow-up after stentless aortic valve replacement. Between 1996 and 2005, 1,014 patients (mean age, 73 years; range, 20 to 90 years) received stentless aortic valve replacement (Freestyle; Medtronic, Minneapolis, MN) and were included into the systematic follow-up that was closed in 2006 with a completeness of 94.7% and a mean follow-up interval of 3 years (range, 0.5 to 9.8 years). Predictors for freedom from cerebrovascular events were identified by Cox regression. Overall survival was 53% +/- 5% after 8 years (mean, 6.8 +/- 0.2 years). Permanent atrial fibrillation at time of surgery was a strong predictor of impaired survival during follow-up. Freedom from cerebrovascular events during follow-up was 68% +/- 5% at 9 years of follow-up. Multivariate regression analysis revealed previous stroke, age at implant, diabetes mellitus, and carotid lesions as significant risk factors. Especially age older than 75 years was a strong risk factor for cerebrovascular events during follow-up (p = 0.004). Atrial fibrillation was not an independent risk factor for cerebrovascular events (p = 0.26) but was a strong predictor of poor survival (p < 0.001) during follow-up. There was no influence of technique of implantation (subcoronary versus full root; p = 0.41), sex (p = 0.35), additional bypass grafting (p = 0.65), and the size of the implanted prosthesis (p = 0.47). The risk of cerebrovascular events during follow-up after stentless aortic valve replacement is related to the individual risk factors of the patients rather than to the valve prosthesis itself. Without additional risk factors, patients with these aortic valve prostheses showed an incidence of cerebrovascular events similar to those reported for a healthy population adjusted for age.

Evaluation of biological aortic valve prostheses by dual source computer tomography and anatomic measurements for potential transapical valve-in-valve procedure

Transapical aortic valve replacement has been introduced into clinical practice from which also patients with failing biological valves might profit: valve-in-valve procedure. The aim of the study was to determine the fate of biological valves in long-term follow-up (FU) and to evaluate topography and dimensions for transapical access via dual-source CT scan (DSCT). Fifty patients (mean age 76+/-13 years, range 38-87 years) underwent DSCT whereas the patients were followed for up to 13 years after porcine aortic valve replacement. Measurements of valve prosthesis and illustration of chest topography were done. Out of 46 evaluable patients, 34 showed no leaflet calcification and 12 minimally calcified. Seventeen valves (37%) showed no, 24 valves (52%) mild and 5 (11%) moderate-to-severe ring calcification. Three patients had moderate aortic stenosis, two patients showed mild insufficiency. The angle from the 4th ICS to apex to aortic valve annulus measured 80.3+/-11.1 degrees compared to the angle from the 5th ICS which measured 101.6+/-7.2 degrees (P<0.0001). Biological valves show good long-term results with minimal failure rate and limited calcification. Leaflet calcification might be problematic if unevenly distributed which can endanger the very close LCO. These measurements represent a prerequisite for preoperative planning and increase the awareness to detect potential procedural problems of the valve-in-valve concept.

Cognitive deficit after aortic valve replacement

Background. Impairment of cognitive brain function after coronary artery bypass grafting (CABG) is well known. In contrast the potential neurocognitive damage related to aortic valve replacement (AVR) is uncertain. Methods. In this contemporary case-matched control study we followed 30 patients (mean age 70 years) receiving isolated AVR with a biological prosthesis. A cohort of sex-and age-matched patients (n = 30, mean age 70 years) receiving CABG with cardiopulmonary bypass served as controls. Cognitive brain function was measured by means of auditory evoked P300 potentials (peak latencies, ms) before the operation and 7 days and 4 months after the operation. Additionally, two standard psychometric tests (Mini-Mental State Examination and the Trailmaking Test A) were performed. Results. In preoperative measures there was no difference between patients undergoing AVR and patients undergoing CABG (AVR 378 ± 37 ms, CABG 374 ± 32 ms, p = 0.629). One week after surgery P300 peak latencies were prolonged (impaired) in both groups compared with preoperative values (AVR 405 ± 43 ms, p = 0.001; CABG 398 ± 44 ms, p = 0.004). At this point of follow-up there was no difference between the groups ( p = 0.607). Finally, 4 months after surgery P300 auditory evoked potentials returned to normal in the CABG group (380 ± 24 ms, p = 0.940) while in contrast in the valve group they continued to become prolonged (worsened) compared with preoperative values (410 ± 47 ms, p = 0.005). At this time of follow-up P300 peak latencies were prolonged in AVR patients as compared with CABG patients ( p = 0.032). The Trailmaking Test A and Mini-Mental State Examination failed to discriminate any difference. Conclusions. Four-month impairment of cognitive brain function is more pronounced in patients undergoing biological AVR as compared with age-matched control patients undergoing CABG. Further studies are needed to clarify the potential pathologic mechanisms causing an ongoing cognitive impairment in patients with biological aortic valve prostheses.

In vitro hydrodynamic characteristics of DE-T2 biological heart valve prosthesis

Our goal was to evaluate the DE-T2 biological heart valve prosthesis in our own pulse duplicator system. Pressure drop measurements were made across DE-T2 biological aortic valve size 21. All the pulsatile flow experiments were conducted in the Marmara Research Center pulse duplicator system. The pulsatile flow pressures were measured with Motorola MPX5100DP 9306 transducers, interfaced to Vishay 4270A, 4280, 4290, bridge amplifiers and Motorola System 4000. The valve DE-T2 had a vitellium ring with a central bar. The sewing ring was covered with bovine pericardium that continued to form the leaflets. A special incision was made in the pericardium at a 90 ° angle to the central bar for the formation of two non-anatomical leaflets. The biological aortic valve prosthesis DE-T2 is similar to the natural aortic valve in systolic function. The closing volume is a little higher than the natural valve. Studies are continuing with the aim of diminishing the closing volume and searching for the ideal preservation solution for the pericardium.

Velocity fields and turbulent stresses downstream of biological and mechanical aortic valve prostheses implanted in pigs.

Since detailed knowledge about velocity fields downstream of heart valve prostheses obtained from in vitro studies has not been followed up by similar detailed studies in vivo a pig model for acute velocity field studies downstream of aortic valve prostheses was established. Two mechanical and two bioprosthetic valves were studied and a dynamic three dimensional visualisation of velocity fields one diameter downstream performed under different haemodynamic conditions in a total of 22 pigs. The Ionescu-Shiley pericardial valve had velocity fields very similar to the normal native porcine aortic valve. The Edwards-Carpentier porcine valve caused a jet type flow, and the valve design of the St Jude Medical and Björk-Shiley Monostrut valves was reflected in the velocity profile. Normalised (mean(SEM] systolic Reynolds normal stresses in the total cross sectional area were: native porcine 15(1.5) Nm-2; St Jude Medical 24(3.4) Nm-2; Björk-Shiley Monostrut 25(1.6) Nm-2; Edwards-Carpentier Supra-annular 51(6.6) Nm-2; Ionescu-Shiley Pericardial 19(2.0) Nm-2. Reynolds normal stresses were higher in areas of rapidly changing or constantly high velocity gradients.