Up to thirty-year survival after aortic valve replacement in the small aortic root

Long-Term Results (up to 20 Years) of 19 mm or Smaller Prostheses in the Aortic Position. Does Size Matter? A Propensity-Matched Survival Analysis

Background: The long-term performance of prostheses in the small aortic root is still unclear. Methods: Patients who received a 21 mm or smaller aortic valve between 2000–2018 were retrospectively analyzed. Propensity matching was used in order to account for baseline differences in 19 mm vs. 21 mm valve subgroups. Results: Survival at 10 years was 55.87 ± 5.54% for 19 mm valves vs. 57.17 ± 2.82% for 21 mm ones in the original cohort (p = 0.37), and 58.69 ± 5.61% in 19 mm valve recipients vs. 53.60 ± 5.66% for 21 mm valve subgroups in the matched cohort (p = 0.55). Smaller valves exhibited significantly more patient–prothesis mismatch (PPM) than larger ones (87.30% vs. 57.94%, p < 0.01). All-cause mortality was affected by PPM at 10 years (52.66 ± 3.28% vs. 64.38 ± 3.87%, p = 0.04) in the unmatched population. This difference disappeared, however, after matching: survival at 10 years was 51.82 ± 5.26% in patients with PPM and 63.12 ± 6.43% in patients without PPM. (p = 0.14) Conclusions: There is no survival penalty in using 19 mm prostheses in the small aortic root in the current era. Although PPM is more prevalent in smaller sized valve recipients, this does not translate into reduced survival at 10 years of follow-up.

Hemodynamic Performance and Outcomes of Mosaic Valve for Aortic Stenosis with Decreased Left Ventricular Function: Results from J-MOVE Study

We evaluated impact of a small-sized Mosaic porcine bioprosthesis on hemodynamic performance and outcomes in patients with aortic stenosis (AS) and low left ventricular ejection fraction (LVEF) in a Japan multicenter cohort. Of 1,202 patients enrolled, 105 (8.7%) who had LVEF < 50% and AS underwent aortic valve replacement (AVR). Fifty-two patients received Mosaic porcine bioprosthesis ≤ 21 mm (S-AVR), and 53 received a bioprosthesis ≥ 23 mm (L-AVR). The median follow-up period was 3.1 [1.2, 5.1] years. At 5 years, LVEF significantly improved from median 41.2 [33.8, 45.9]% to 64.2 [49.8, 72.5]% in S-AVR (p < 0.001) and from median 43.2 [37.3, 46.8]% to 61.2 [47.2, 68.0]% in L-AVR (p < 0.001). The left ventricular mass index significantly decreased from median 158.4 [122.2, 194.9] to 110.0 [83.6, 129.4] gm/m in S-AVR (p < 0.001) and from median 169.8 [132.2, 203.6] to 109.6 [101.8, 132.4] gm/m in L-AVR (p < 0.001). There were no significant differences between S-AVR and L-AVR groups regarding freedom from cardiac death (93.1 ± 3.9% vs. 96.2 ± 3.8%; p = 0.119) and valve-related death (97.6 ± 2.4% vs. 100.0 ± 0.0%; p = 0.953). Clinical outcomes and improved hemodynamic performance were similar in both groups.

Early and Mid-term Outcome of the St. Jude Medical Regent 19-mm Aortic Valve Mechanical Prosthesis. Functional and Haemodynamic Evaluation

BACKGROUND AND OBJECTIVES

The aim of the present study is to report the early and mid-term clinical and haemodynamic results of the St Jude Medical Regent 19-mm aortic mechanical prothesis (SJMR-19).

MATERIALS AND METHODS

Between January 2002 and January 2012, 265 patients with aortic valve disease underwent AVR (Aortic Valve Replacement) with a SJMR-19 (St Jude Medical Regent Nr.19). There were 51 males. Mean age was 67.5±12.72years and mean body surface area (BSA) was 1.67±0.14m2. Thirty-six patients required annulus enlargement. The mean follow-up was 34.5±18.8months (range 6-60 months). All patients underwent echocardiographic examination at discharge and within 1 year after surgery.

RESULTS

There were 14 (5.3%) hospital deaths. Six of the hospital deaths were identified in patients undergoing reoperation, significantly higher than patients undergoing first time operation (p=0.0001). Also the postoperative mortality was significantly higher in patients undergoing annulus enlargement versus patients not requiring annulus enlargement (p=0.02). The mean transprosthesis gradient at discharge was 19±9mmHg. At 6 months follow-up the mean NYHA FC class was 1.6±0.5 significantly lower than preoperatively 2.4±0.75 (p <0.0001). The M-TPG was 15.2±6.5mmHg within 1 year after surgery. Left ventricular mass (LVM) and indexed left ventricular mass (LVM_i) were significantly lower than preoperatively The actuarial survival and cumulative freedom from reoperation at 1, 2 and 3 years follow-up were 99.5%, 97.5%, 96.7% and 99.2%, 96.5%, 94.5% respectively. The cumulative actuarial free-events survival at 4 years was 92%. The Cox model identified age (p=0.015), LVEF≤35% (p=0.043), reoperation (p=0.031), combined surgery (p=0.00002), and annulus enlargement (p=0.015) as strong predictors for poor actuarial free-major events survival.

CONCLUSIONS

The SJMR-19 offers excellent postoperative clinical, haemodynamic outcome and LVM_i reduction in patients with small aortic annulus. These data demonstrate that the modern St Jude small mechanical protheses do not influence the intermediate free-reoperation survival.

Long-term Mortality Predictors in Patients with Small Aortic Annulus Undergoing Aortic Valve Replacement with a 19- or 21-mm Bioprosthesis

Introduction

Replacement of the aortic valve in patients with a small aortic annulus is associated with increased morbidity and mortality. A prosthesis-patient mismatch is one of the main problems associated with failed valves in this patient population.

Objective

To evaluate the long-term mortality predictors in patients with a small aortic annulus undergoing aortic valve replacement with a bioprosthesis.

Methods

In this retrospective observational study, a total of 101 patients undergoing aortic valve replacement from January 2000 to December 2010 were studied. There were 81 (80.19%) women with a mean age of 52.81±18.4 years. Severe aortic stenosis was the main indication for surgery in 54 (53.4%) patients. Posterior annulus enlargement was performed in 16 (15.8%) patients. Overall, 54 (53.41%) patients underwent concomitant surgery: 28 (27.5%) underwent mitral valve replacement, and 13 (12.7%) underwent coronary artery bypass graft surgery.

Results

Mean valve index was 0.82±0.08 cm(2)/m(2). Overall, 17 (16.83%) patients had a valve index lower than 0.75 cm(2)/m(2), without statistical significance for mortality (P=0.12). The overall 10-year survival rate was 83.17%. The rate for patients who underwent isolated aortic valve replacement was 91.3% and 73.1% (P=0.02) for patients who underwent concomitant surgery. In the univariate analysis, the main predictors of mortality were preoperative ejection fraction (P=0.02; HR 0.01) and EuroSCORE II results (P=0.00000042; HR 1.13). In the multivariate analysis, the main predictors of mortality were age (P=0.01, HR 1.04) and concomitant surgery (P=0.01, HR 5.04). Those relationships were statistically significant.

Conclusion

A valve index of < 0.75 cm(2)/m(2) did not affect 10-year survival. However, concomitant surgery and age significantly affected mortality.

Aortic Valve Replacement without Annular Enlargement in Patients with Small Aortic Roots

Use of small prostheses for aortic valve replacement eliminates the need for annular enlargement but may impair symptomatic resolution and long-term patient survival. We reviewed our experience with 105 consecutive patients who had isolated aortic valve replacement with small mechanical prostheses or bioprostheses (14 to 21 mm) without concurrent annular enlargement between August 1976 and November 1992. The mean age was 72 ± 10 years and 82% of patients were female. Valvular disease was primarily aortic stenosis in 61%, aortic regurgitation in 7%, and mixed aortic disease was present in 32% of patients. Mean preoperative ejection fraction was 64% ± 17% and the aortic valve area was 0.5 ± 0.2 cm2. Prior to surgery, 82% of patients were in New York Heart Association functional class III or IV. The mean duration of follow-up was 8.1 years. There were 7 early and 14 late deaths giving an overall survival of 80% and a 10-year Kaplan-Meier survival rate of 77%. Five patients developed thromboembolic complications (transient stroke) and 2 required repeat aortic valve replacement due to prosthetic valve endocarditis. Doppler echocardiography or cardiac catheterization was performed in 15 patients postoperatively but peak systolic gradient exceeded 50 mm Hg in only one individual with a 21-mm porcine valve. All surviving patients were in functional class I or II. We conclude that aortic valve replacement with small prostheses is associated with excellent long-term patient survival, improvement in clinical symptoms, and a low incidence of complications.

Early and mid-term outcome in terms of functional and hemodynamic performance of the st. Jude regent 19-mm aortic mechanical prosthesis versus 19-mm carpentier edwards aortic biological prosthesis

BACKGROUND

The aim of the present study is to compare the early and mid-term clinical and hemodynamic results of the aortic valve replacement (AVR) with a St Jude Medical Regent 19-mm prosthesis (SJMR-19) versus Carpentied-Edwars bovine pericardial 19-mm valve (CE-19).

METHODS

Between January 2002 and January 2012, 265 patients (Group I) and 58 patients (Group II) with underwent AVR with a SJMR-19 and CE-19 respectively. There were no significant differences between groups regarding the demographic and preoperative echocardiographic data. Thirty-six patients in Group I and 4 in Group II required annulus enlargement in association or not with septal myectomy. The mean follow-up was 34 ± 18.5 months (range 5-60 months).

RESULTS

There were 14 (5.3 %) hospital deaths in Group I versus 4 (6.8 %) in Group II (p = 0.86). The multivariate logistic regression analysis identified the LVEF ≤ 35 % (p = 0.001), combined operation (p = 0.0005), CPB (p = 0.033), age (p = 0.011), annulus enlargement (p = 0.0009), reoperation (p = 0.039) and chronic renal failure (p = 0.011) as strong predictors for early postoperative death. Within 1 year after surgery peak pulmonary artery pressure, interventricular septal and left ventricular posterior wall thickness decreased significantly in both groups. The M-TPG was 15.7 ± 6.5 mmHg in Group I versus 17 ± 7 mmHg in Group II (p = 0.19). The multivariate regression analysis revealed the annulus enlargement (p = 0.018), small EOAi (p = 0.00004), postoperative LVMi (p = 0.0001) and BSA (p = 0.019) as strong predictors for higher M-TPG. The postoperative LVMi was 119 ± 22.5 gm/m(2) in Group I and 122 ± 22 gm/m(2) in Group II (p = 0.37), significantly lower than the respective preoperative values 162.5 ± 34 gm/m(2) (Group I) and 168 ± 30 gm/m(2) (Group II). The actuarial survival and cumulative free-reoperation actuarial survival at 5 years follow-up were 96.7 and 94.5 % respectively in Group I and 97 and 91 % in Group II.. There were non significant differences between groups regarding the actuarial survival and cumulative free-reoperation survival. The Cox model identified the older age (p = 0.022), LVEF ≤ 35 % (p = 0.009), reoperation (p = 0.018), combined surgery (p = 0.00075) and annulus enlargement (p = 0.033) as strong predictors for poor actuarial free-reoperation survival.

CONCLUSIONS

Both the SJMR-19 and CE-19 offers excellent postoperative clinical and hemodynamic outcome in patients with small aortic annulus. The LV hypertrophy and transvalvular gradients are reduced significantly indenpendently of the employed SJMR-19 or CE-19 prosthesis. Our data support recent suggestions that small valve size does not influence intermediate free-reoperation survival. The CE-19 is an excellent alternative to SJMR-19 in old patients.

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.

Rigorous patient-prosthesis matching of Perimount Magna aortic bioprosthesis

Background

Severe patient-prosthesis mismatch, defined as effective orifice area index ≤0.65 cm2 m−2, has demonstrated poor long-term survival after aortic valve replacement. Reported rates of severe mismatch involving the Perimount Magna aortic bioprosthesis range from 4% to 20% in patients with a small annulus.

Methods

Between June 2008 and August 2011, 251 patients (mean age 70.5 ± 10.2 years; mean body surface area 1.55 ± 0.19 m2) underwent aortic valve replacement with a Perimount Magna bioprosthesis, with or without concomitant procedures. We performed our procedure with rigorous patient-prosthesis matching to implant a valve appropriately sized to each patient, and carried out annular enlargement when a 19-mm valve did not fit. The bioprosthetic performance was evaluated by transthoracic echocardiography predischarge and at 1 and 2 years after surgery.

Results

Overall hospital mortality was 1.6%. Only 5 (2.0%) patients required annular enlargement. The mean follow-up period was 19.1 ± 10.7 months with a 98.4% completion rate. Predischarge data showed a mean effective orifice area index of 1.21 ± 0.20 cm2 m−2. Moderate mismatch, defined as effective orifice area index ≤0.85 cm2 m−2, developed in 4 (1.6%) patients. None developed severe mismatch. Data at 1 and 2 years showed only two cases of moderate mismatch; neither was severe.

Conclusions

Rigorous patient-prosthesis matching maximized the performance of the Perimount Magna, and no severe mismatch resulted in this Japanese population of aortic valve replacement patients.

Speckle tracking echocardiography derived 2-dimensional myocardial strain predicts left ventricular function and mass regression in aortic stenosis patients undergoing aortic valve replacement

Regression of left ventricular (LV) mass in severe aortic stenosis (AS) following aortic valve replacement (AVR) reduces the potential risk of sudden death and congestive heart failure associated with LV hypertrophy. We investigated whether abnormalities of resting LV deformation in severe AS can predict the lack of regression of LV mass following AVR. Two-dimensional speckle tracking echocardiography (STE) was performed in a total of 100 subjects including 60 consecutive patients with severe AS having normal LV ejection fraction (EF > 50 %) and 40 controls. STE was performed preoperatively and at 4 months following AVR, including longitudinal strain assessed from the apical 4-chamber and 2-chamber views and the circumferential and rotational mechanics measured from the apical short axis view. In comparison with controls, the patients with AS showed a significantly lower LV longitudinal (p < 0.001) and circumferential strain (p < 0.05) and higher apical rotation (p < 0.001). Following AVR, a significant improvement was seen in both strains (p < 0.001 for each respectively), however, apical rotation remained unchanged (p = 0.14). On multivariate analysis, baseline LV mass (odds ratio 1.02; p = 0.011), left atrial volume (odds ratio 0.81; p = 0.048) and circumferential strain (odds ratio 0.84; p = 0.02) independently predicted LV mass regression (>10 %) following AVR. In conclusion, STE can quantify the burden of myocardial dysfunction in patients with severe AS despite the presence of normal LV ejection fraction. Furthermore, resting abnormalities in circumferential strain at LV apex is related with a hemodynamic milieu associated with the lack of LV mass regression during short-term follow up after AVR.

Aortic valve replacement with smaller valve size

The occurrence of prosthesis-patient mismatch after aortic valve replacement with a small valve size was evaluated in 249 patients, focusing on echocardiographic data. Aortic valve pathology included regurgitation in 174 patients and stenosis in 75. Echocardiography was performed in the early and late postoperative periods. A projected effective orifice area index < 0.85 cm(2)·m(-2) was noted in 56 patients; values ≥ 0.85 cm(2)·m(-2) were found in 128. Postoperative changes in ejection fraction, left ventricular mass regression, and peak transprosthetic gradient were similar in both groups. Small prostheses (≤ 19 mm) were used in 43 patients who had significantly higher postoperative transprosthetic gradients in both the early and late periods, compared to those with larger prostheses. Our findings show that the occurrence of prosthesis-patient mismatch after aortic valve replacement is rare. Left ventricular mass regression occurred in most patients, with acceptable transprosthetic gradients.

Comparative evaluation of left ventricular mass regression after aortic valve replacement: a prospective randomized analysis

BACKGROUND

We assessed the hemodynamic performance of various prostheses and the clinical outcomes after aortic valve replacement, in different age groups.

METHODS

One-hundred-and-twenty patients with isolated aortic valve stenosis were included in this prospective randomized randomised trial and allocated in three age-groups to receive either pulmonary autograft (PA, n = 20) or mechanical prosthesis (MP, Edwards Mira n = 20) in group 1 (age < 55 years), either stentless bioprosthesis (CE Prima Plus n = 20) or MP (Edwards Mira n = 20) in group 2 (age 55-75 years) and either stentless (CE Prima Plus n = 20) or stented bioprosthesis (CE Perimount n = 20) in group 3 (age > 75). Clinical outcomes and hemodynamic performance were evaluated at discharge, six months and one year.

RESULTS

In group 1, patients with PA had significantly lower mean gradients than the MP (2.6 vs. 10.9 mmHg, p = 0.0005) with comparable left ventricular mass regression (LVMR). Morbidity included 1 stroke in the PA population and 1 gastrointestinal bleeding in the MP subgroup. In group 2, mean gradients did not differ significantly between both populations (7.0 vs. 8.9 mmHg, p = 0.81). The rate of LVMR and EF were comparable at 12 months; each group with one mortality. Morbidity included 1 stroke and 1 gastrointestinal bleeding in the stentless and 3 bleeding complications in the MP group. In group 3, mean gradients did not differ significantly (7.8 vs 6.5 mmHg, p = 0.06). Postoperative EF and LVMR were comparable. There were 3 deaths in the stented group and no mortality in the stentless group. Morbidity included 1 endocarditis and 1 stroke in the stentless compared to 1 endocarditis, 1 stroke and one pulmonary embolism in the stented group.

CONCLUSIONS

Clinical outcomes justify valve replacement with either valve substitute in the respective age groups. The PA hemodynamically outperformed the MPs. Stentless valves however, did not demonstrate significantly superior hemodynamics or outcomes in comparison to stented bioprosthesis or MPs.

Stentless aortic valve replacement: an update

Although porcine aortic valves or pericardial tissue mounted on a stent have made implantation techniques easier, these valves sacrifice orifice area and increase stress at the attachment of the stent, which causes primary tissue failure. Optimizing hemodynamics to prevent patient–prosthetic mismatch and improve durability, stentless bioprostheses use was revived in the early 1990s. The purpose of this review is to provide a current overview of stentless valves in the aortic position. Retrospective and prospective randomized controlled studies showed similar operative mortality and morbidity in stented and stentless aortic valve replacement (AVR), though stentless AVR required longer cross-clamp and cardiopulmonary bypass time. Several cohort studies showed improved survival after stentless AVR, probably due to better hemodynamic performance and earlier left ventricular (LV) mass regression compared with stented AVR. However, there was a bias of operation age and nonrandomization. A randomized trial supported an improved 8-year survival of patients with the Freestyle or Toronto valves compared with Carpentier–Edwards porcine valves. On the contrary, another randomized study did not show improved clinical outcomes up to 12 years. Freedom from reoperation at 12 years in Toronto stentless porcine valves ranged from 69% to 75%, which is much lower than for Carpentier–Edwards Perimount valves. Cusp tear with consequent aortic regurgitation was the most common cause of structural valve deterioration. Cryolife O’Brien valves also have shorter durability compared with stent valves. Actuarial freedom from reoperation was 44% at 10 years. Early prosthetic valve failure was also reported in patients who underwent root replacement with Shelhigh stentless composite grafts. There was no level I or IIa evidence of more effective orifice area, mean pressure gradient, LV mass regression, surgical risk, durability, and late outcomes in stentless bioprostheses. There is no general recommendation to prefer stentless bioprostheses in all patients. For new-generation pericardial stentless valves, follow-up over 15 years is necessary to compare the excellent results of stented valves such as the Carpentier–Edwards Perimount and Hancock II valves.

On the multiscale modeling of heart valve biomechanics in health and disease

Theoretical models of the human heart valves are useful tools for understanding and characterizing the dynamics of healthy and diseased valves. Enabled by advances in numerical modeling and in a range of disciplines within experimental biomechanics, recent models of the heart valves have become increasingly comprehensive and accurate. In this paper, we first review the fundamentals of native heart valve physiology, composition and mechanics in health and disease. We will then furnish an overview of the development of theoretical and experimental methods in modeling heart valve biomechanics over the past three decades. Next, we will emphasize the necessity of using multiscale modeling approaches in order to provide a comprehensive description of heart valve biomechanics able to capture general heart valve behavior. Finally, we will offer an outlook for the future of valve multiscale modeling, the potential directions for further developments and the challenges involved.

Up to twenty-five-year survival after aortic valve replacement with size 19 mm valves

Long-term survival was investigated in 202 patients who underwent isolated aortic valve replacement (AVR) with 19 mm valves. There were 171 women with a mean age of 69+/-9 years and 31 men with a mean age of 64+/-13 years. Patients had a mean body surface area of 1.61+/-0.13 m(2). Patient-prosthesis mismatch was moderate in 196 and severe in six patients. The mean follow-up for all patients was 78 months. There were 79 late deaths. The actuarial survival rates for all patients were 95+/-1% at 1 year, 75+/-2% at 5 years, 56+/-2% at 10 years, 41+/-2% at 15 years, 34+/-3% at 20 years and 34+/-2% at 25 years. Patients over 70 years old had a lower survival rate (P=0.0001). There were significant differences between ejection fraction (EF) >55% and EF <55% (P=0.0305). AVR with 19 mm valves appeared to provide satisfactory mid-term survival. Age and low EF were risk factors for shorter survival.

Twenty-Five–Year Experience With the Medtronic-Hall Valve Prosthesis in the Aortic Position

Background— The Medtronic-Hall valve was developed and for the first time implanted in Oslo, Norway, in 1977. A total of 1104 patients received this valve at Rikshospitalet from 1977 to 1987. In the present study, we followed up on all 816 patients undergoing aortic valve replacement over a 25-year period.

Methods and Results— This is a retrospective cohort analysis of 816 consecutive patients undergoing aortic valve replacement with the Medtronic-Hall valve at Rikshospitalet, Oslo, Norway, from 1977 to 1987. All patients were contacted by means of questionnaires or telephone. Data were checked against hospital databases and medical records. Date of death was verified by the Norwegian civil registry. Follow-up was 99.6% complete. Survival analysis included operative deaths as well as late deaths. Survival at 25 years was 24.9%. No mechanical failures were found. Valve thrombosis was seen in 4 patients, in 1 case combined with pannus formation. Small valves (20 mm to 21 mm) were associated with reduced survival; however, when controlled for the confounding effects of age and gender, valve size did not remain a significant risk factor. Patient-related factors were important: Older age, female gender, and the need for concomitant coronary artery bypass surgery significantly reduced survival, whereas surgery of the ascending aorta did not. Linearized rates of thromboembolic complications, warfarin-related bleeding, and endocarditis were 1.5%, 0.7%, and 0.16%/patient-year, respectively. At follow-up, 79% of the patients were in New York Heart Association classes I to II.

Conclusions— This study confirms the excellent long-term outcome for patients with Medtronic-Hall valves in the aortic position.

Meta-Analysis of Valve Hemodynamics and Left Ventricular Mass Regression for Stentless Versus Stented Aortic Valves

BACKGROUND

Stentless aortic bioprostheses have been advocated as being superior to conventional bioprosthetic valves, with benefits including superior left ventricular mass regression and larger effective orifice area. Several high-quality randomized studies now exist on this topic, and we sought to summarize them by meta-analysis.

METHODS

The literature was searched from 1995 to 2006, in MEDLINE, EMBASE, CRISP, metaRegister of Controlled Trials, and the Cochrane database. Experts were also contacted and reference lists searched. Studies were combined using the inverse variance fixed-effects model. Heterogeneity was assessed and a sensitivity analysis performed. Publication bias was also investigated.

RESULTS

Ten studies were identified that included 919 patients in which the Freedom (Sorin Biomedica Cardio, Via Crescentino, Italy), Freestyle (Medtronic, Minneapolis, MN), Prima Plus (Edwards Life Sciences, Irvine, CA) and the Toronto and Biocor (St Jude Medical, St. Paul, MN) valves were used. The mean aortic valve gradient was lower in the stentless groups, with a weighted mean difference (WMD) of -3.57 mm Hg (95% confidence interval [CI], -4.36 to -2.78; p < 0.01). The left ventricular mass index was significantly lower in the stentless groups at 6 months (WMD, -6.42; 95% CI, -11.63 to -1.21; p = 0.02), but this improvement disappeared after 12 months (WMD, 1.19; 95% CI, -4.15 to 6.53; p = 0.66). The weighted mean increase in cross-clamp time was 23 minutes, and the increase in bypass time was 29 minutes with a stentless valve.

CONCLUSIONS

This meta-analysis showed that stentless aortic valves provide an improved level of left ventricular mass regression at 6 months, reduced aortic gradients, and an improved effective orifice area index, at the expense of a 23-minute longer cross-clamp time and a 29-minute longer bypass time.

Early Clinical and Hemodynamic Outcomes After Stented and Stentless Aortic Valve Replacement: Results From a Randomized Controlled Trial

BACKGROUND

Stentless aortic bioprostheses were shown to be hemodynamically superior to earlier generations of stented bioprostheses. Modern stented valve designs have improved hemodynamics. A prospective randomized controlled trial was undertaken to compare stentless versus modern stented valves. Our aim was to determine any differences in early postoperative clinical and hemodynamic outcomes.

METHODS

Patients with severe aortic valve stenosis (n = 161) undergoing aortic valve replacement were randomized intraoperatively to receive either the C-E Perimount (Edwards Lifesciences, Irvine, CA) pericardial stented bioprosthesis (n = 81) or the Prima Plus (Edwards Lifesciences) (porcine stentless bioprosthesis (n = 80). Transthoracic echocardiograms were performed at one week and eight weeks postoperatively to assess left ventricular mass (LVM) and transvalvular gradients (TVG).

RESULTS

There were no differences between the two groups in baseline characteristics. Cardiopulmonary bypass and ischemic times were longer in the stentless group. Despite similar native aortic annular diameters, the mean size of the prosthesis used in the stentless group was 2.1 mm (SD = 2.8) larger (p < 0.001). Early (30-day) mortality (stentless 3.7% vs stented 2.5%; p = 0.68) and morbidity was similar between groups. Eight weeks postoperatively, LVM (stentless 199 +/- 70 vs stented 204 +/- 66 grams; p = 0.32) and TVG decreased in both groups (mean systolic gradient; stentless 10 +/- 3 vs stented 10 +/- 4 mm Hg; p = 0.54) but there was no significant difference between groups.

CONCLUSIONS

Despite longer ischemic times in the stentless group, early postoperative outcomes were similar. Both stented and stentless aortic valve replacement offers excellent hemodynamics and can be achieved with low perioperative mortality.

Stented versus Stentless Bioprostheses in Aortic Valve Stenosis: Effect on Left Ventricular Remodelling

BACKGROUND

Whether the use of stentless aortic bioprostheses improves hemodynamics more than stented bioprostheses in the small aortic root is still a matter of debate.

METHODS

Early- and mid-term effects were compared between 2 different types of stentless bioprotheses and 1 type of stented bioprosthesis for left ventricular remodelling. The effects of the bioprotheses were studied by echocardiography in 68 patients (age, 74 +/- 7 years) with aortic annulus diameter < or =23 mm who were undergoing prosthesis implantation due to aortic isolated stenosis. Stented bioprostheses (Carpentier-Edwards Perimount [CEP]) were implanted in 36 subjects and stentless bioprostheses (18 Toronto SPV and 14 Shelhigh Super Stentless) were implanted in 32 subjects.

RESULTS

A progressive and similar decrease in left ventricular mass of 30% was observed in both stented and stentless bioprostheses at 12 months. A progressive increase in transprosthetic effective orifice area and a decrease in transprothetic pressure gradient were observed at 3, 6, and 12 months in the Toronto group, but these variables showed improvement only at 3 months in the CEP and Shelhigh groups. No mortality occurred during surgery or during the 1-year follow-up period.

CONCLUSIONS

Our results confirmed good feasibility of aortic stented and stentless bioprostheses implantation in the elderly population. A 30% decrease in left ventricular mass occurred in the early- and mid-term (12 months) periods after surgery with all 3 types of bioprostheses. Advantages consisting of a progressive increase in transprosthetic effective orifice area and a decrease of the transprosthetic pressure gradient were observed in the Toronto group in comparison to the CEP and Shelhigh groups. These observations may help surgeons in choosing bioprostheses.

A novel multi-planed mechanical aortic valve for increasing the effective orifice area

BACKGROUND

Today, there is still confusion about mismatch of the orifice area of the mechanical valve and body surface area of the patient in aortic valve surgery. Creating a larger effective orifice area is the aim with this new valve design.

METHOD

This valve is multi-planed, one housing is seated at the aortic annulus for the coronary orifices to receive blood in diastole, the other housing or housings are seated to the ascending aorta obliquely to increase the orifice area of the valve. The ascending aorta can be enlarged if necessary.

RESULT

Valves with orifice areas larger than 6 cm(2) can be achieved with multi-planed aortic valves.

DISCUSSION

The use of this valve depends on the fact that the aorta is a living tissue and can grow over time to normal values.

Impact of Stentless Aortic Valves on Left Ventricular Function and Hypertrophy: Current Best Available Evidence

Past four decades have seen a gradual evolution in aortic valve replacement surgery. The ideal valve substitute should combine central flow, low transvalvular gradient, low thrombogenicity, durability, easy availability, resistance to infection, freedom from anticoagulation, and easy implantability. Although there are several types of valves available to replace the diseased aortic valve-autograft, allograft, xenograft, mechanical, and bioprosthetic valves-none is ideal. On one end of the spectrum is the pulmonary autograft, which comes closest to achieving these goals, but creates a double valve procedure for single valve disease, while on the other end are the mechanical valves and stented tissue valves, which allow easy "off the shelf" availability as well as easy implantability but are limited by the potential drawback of causing intrinsic obstruction to some extent because of the space occupied by the stent and sewing ring. Stentless xenograft aortic valves have been developed as a compromise between these ends of the valve spectrum. Stentless aortic valves have been reported to provide more physiologic hemodynamic behavior and cause more timely and thorough regression of ventricular hypertrophy. This review article attempts to evaluate current best available evidence from randomized controlled trials to assess the impact of stentless aortic valves on left ventricular function and hypertrophy.

Prosthesis-Patient Mismatch After Aortic Valve Replacement: Impact of Age and Body Size on Late Survival

BACKGROUND

The purpose of this study was to identify patient subgroups in which prosthesis-patient mismatch most influenced late survival.

METHODS

Over a 12-year period, 1,400 consecutive patients underwent bioprosthetic (933 patients) or mechanical (467) aortic valve replacement. Prosthesis-patient mismatch was defined as prosthetic effective orifice area/body surface area less than 0.75 cm2/m2 and was present with 11% mechanical and 51% bioprosthetic valves.

RESULTS

With bioprosthetic valves, prosthesis-patient mismatch was associated with impaired survival for patients less than 60 years old (10-year: 68% +/- 7% mismatch versus 75% +/- 7% no mismatch, p < 0.02) but not older patients (p = 0.47). Similarly, with mechanical valves, prosthesis-patient mismatch was associated with impaired survival for patients less than 60 years old (10-year: 62% +/- 11% versus 79% +/- 4%, p < 0.005) but not older patients (p = 0.26). For small patients (body surface area less than 1.7 m2), prosthesis-patient mismatch did not impact survival with bioprosthetic (p = 0.32) or mechanical (p = 0.71) valves. For average-size patients (body surface area 1.7 to 2.1 m2), prosthesis-patient mismatch was associated with impaired survival with both bioprosthetic (p < 0.05) and mechanical (p < 0.005) valves. For large patients (body surface area greater than 2.1 m2), prosthesis-patient mismatch was associated with impaired survival with mechanical (p < 0.04) but not bioprosthetic (p = 0.40) valves.

CONCLUSIONS

Prosthesis-patient mismatch had a negative impact on survival for young patients, but its impact on older patients was minimal. In addition, although prosthesis-patient mismatch was not important in small patients, prosthesis-patient mismatch negatively impacted survival for average-size patients and for large patients with mechanical valves.

Do pulmonary autografts provide better outcomes than mechanical valves? A prospective randomized trial

BACKGROUND

The objective of this study was to compare the performance of pulmonary autografts with mechanical aortic valves, in the treatment of aortic valve stenosis.

METHODS

Forty patients with aortic valve stenoses, and below the age of 55 years, were randomly assigned to receive either pulmonary autografts (n = 20) or mechanical valve (Edwards MIRA; Edwards Lifesciences, Irvine, CA) prostheses (n = 20). Clinical outcomes, left ventricular mass regression, effective orifice area, ejection fraction, and mean gradients were evaluated at discharge, 6 months, and one year after surgery. Follow-up was complete for all patients.

RESULTS

Hemodynamic performance was significantly better in the Ross group (mean gradient 2.6 mm Hg vs 10.9 mm Hg, p = 0.0005). Overall, a significant decrease in left ventricular mass was found one year postoperatively. However, there was no significant difference in the rate and extent of regression between the groups. There was one stroke in the Ross group and one major bleeding complication in the mechanical valve group. Both patients recovered fully.

CONCLUSIONS

In our randomized cohort of young patients with aortic valve stenoses, the Ross procedure was superior to the mechanical prostheses with regard to hemodynamic performance. However, this did not result in an accelerated left ventricular mass regression. Clinical advantages like reduced valve-related complications and lesser myocardial strain will have to be proven in the long term.

Experimental study of a multiplaned mechanical aortic valve using bovine aorta

A newly designed multiplaned mechanical aortic valve was created in which there would be an angle between the stents so the valve would have a greater orifice area. This study was performed to test this valve on bovine aorta to determine whether or not there would be a pressure gradient on both sides of the valve. The valve created is multiplaned with one stent thought to be seated on the aortic annulus for the coronary orifices to receive blood in diastole, whereas the other stent is thought to be seated on the ascending aorta obliquely to increase the orifice area of the valve. The ascending aorta could be enlarged if necessary. A multiplaned valve resembling the valve which has two planes was tested on a Dacron tube, one side of which was formed with a bovine aorta. Pressure readings before and after the bovine aorta was thinned were taken when a 17 L/min flow through the tube was maintained. A 65 mmHg mean pressure gradient and a zero pressure gradient were produced before and after thinning the bovine aorta. The multiplaned mechanical aortic valve produces no gradient if the aorta is elastic. This valve can solve the gradient problem in aortic valve surgery because the aorta is a living and elastic tissue.

Reoperation for a Starr-Edwards aortic prosthetic valve 33 years after initial implantation

A 40-year-old woman admitted with heart failure had undergone aortic valve replacement with a Model 2310 Starr-Edwards valve due to aortic regurgitation 33 years previously. She had been followed up for several years, but discontinued follow-up and medication (including Warfarin) for the past 25 years. Echocardiography demonstrated marked dilatation and thickening of the left ventricle, and the peak pressure gradient of the prosthesis was measured as 87.9 mmHg. Under the diagnosis of chronic aortic valve prosthesis-patient mismatch with subsequent severe left ventricular dysfunction, the Starr-Edwards valve was explanted and replaced with a 23 mm St. Jude Medical prosthetic valve. The removed valve showed minimal cloth wear except for a small part of the strut. The postoperative echocardiography demonstrated recovering of left ventricular function. To our best knowledge, this case presents the longest duration for a surgically explanted Starr-Edwards aortic prosthetic valve in Japan.

Early Regional Assessment of LV Mass Regression and Function after Stentless Valve Replacement: Comparative Randomized Study

Early regional performance and hypertrophy regression after stentless aortic valve replacement are still incompletely characterized. We compared early postoperative changes of segmental thickness and function after stentless and stented aortic valve replacement as assessed by cardiac magnetic resonance (CMR). In 16 patients randomly assigned to stented (Mosaic, 8 patients) and stentless (Freestyle, 8 patients) groups, 4 parallel short-axis images at the level of the apex (slice 4), midventricle (slices 2-3), and mitral valve (slice 1) were obtained with a 1.5 T CMR scanner (Magnetom Sonata, Siemens) before and 1 month after surgery. Cine images were obtained using an echo gradient sequence. Left ventricle mass was calculated as the difference between the left ventricular end-diastolic volume at the epicardial and endocardial borders multiplied by a myocardium density factor (1.05). Each slice was divided into 8 segments (octants) from anterior (octant I-II) to septal (octant V-VIII). A total of 32 segments encompassed the entire heart. From each of these elements end diastolic thickness and systolic function (fractional thickening) were calculated. In stentless valves significant reduction of septal octant thickness on the midventricular slice was noted. There was no difference in regional systolic function-segment thickening. In stented valves no segmental thickness changes were observed. In stentless valves there was early postoperative thickness reduction of septal segments at the midventricular level. However, this finding did not coincide with changes in segmental function.

Small aortic annulus: The hydrodynamic performances of 5 commercially available bileaflet mechanical valves

OBJECTIVE

Hemodynamic performances of mechanical valve prostheses in patients with aortic valve stenosis and a small aortic annulus are crucial. We analyzed the in vitro hydrodynamics of 5 currently available bileaflet mechanical prostheses that fitted a 21-mm-diameter valve holder of a Sheffield pulse duplicator.

METHODS

Three samples of 5 high-performance production-quality prostheses, including the sewing ring cuffs, were tested in the aortic chamber of a Sheffield pulse duplicator. Sizes of the prostheses fitting the 21-mm valve holder were as follows: 18-mm ATS, 19-mm SJM Regent, 19-mm Sorin Bicarbon Slimline, 19-mm On-X, and 21-mm Carbomedics Top Hat. The tests were carried out at a fixed pulse rate (70 beats/min) and at increasing cardiac outputs of 2, 4, 5, and 7 L/min. Each valve was tested 10 times for each different cardiac output. This resulted in a total of 40 tests for each valve and 120 tests for each valve model. The aortic pressure was set at 120/80 mm Hg (mean pressure, 100 mm Hg) throughout the experiment for all cardiac outputs. Forward flow pressure decrease, total regurgitant volume, closing and leakage volumes, effective orifice area, and stroke work loss were recorded while the valve operated under each cardiac output.

RESULTS

The SJM Regent valve and the Sorin Bicarbon Slimline prosthesis showed the lowest mean and peak gradients at increasing cardiac outputs. The closure volume was higher for the SJM Regent and Sorin Bicarbon Slimline prostheses, unlike with the ATS prosthesis at 7 L/min of cardiac output. The ATS and SJM Regent prostheses showed the largest regurgitant volume, whereas the Sorin Bicarbon Slimline prosthesis showed the lowest regurgitant volume. The calculated effective orifice area and stroke work loss were significantly better with the SJM Regent and Sorin Bicarbon Slimline prostheses.

CONCLUSION

Assuming that the 21-mm valve holder in which all the tested prostheses were accommodated is comparable with a defined aortic valve size, this hydrodynamic evaluation model allowed us to compare the efficiency of currently available valve prostheses, and among these, the SJM Regent and the Sorin Bicarbon Slimline exhibited the best performances.

Hemodynamic and clinical outcomes with the biocor valve in the aortic position: an 8-year experience

OBJECTIVES

The aim of this study was to analyze the 8-year experience, survival, prosthetic complications, and hemodynamics of patients who received the Biocor valve, a new-generation tissue valve, in the aortic position.

METHODS

From May 1992 through May 2001, 257 consecutive patients (129 women and 128 men; mean age, 75 +/- 6 years; age range, 45-91 years) received 258 aortic Biocor porcine prostheses. One female patient who received 2 Biocor valves in the aortic position during 2 consecutive operations was entered twice in the statistical analysis. Twelve (4.6%) patients had previous aortic valve operations. Preoperatively, 82 (32%) patients were in New York Heart Association functional class III or IV. Associated surgical procedures included coronary artery bypass grafting in 56 (21.7%) patients, aortic annular enlargement or aortoplasty in 20 (8%) patients, and others in 8 (3%) patients. Echocardiography was performed in the majority of long-term survivors (91.6%). Follow-up included 1215 patient-years and was 100% complete, with a median time of 5 patient-years (range, 0.4-10.5 years).

RESULTS

There were 16 (6.2%) early deaths. According to a univariate analysis, New York Heart Association functional class III or IV, concomitant procedures, ejection fractions of less than 40%, and urgent operations were identified as significant perioperative risk factors. At follow-up, 75 patients died; 8-year actuarial Kaplan-Meier survival was 48% +/- 5%. At 8 years, the actuarial freedom from valve-related death was 92% +/- 2.6%, the freedom from thromboembolism was 93% +/- 2%, the freedom from anticoagulant-related hemorrhage was 95% +/- 2%, the freedom from endocarditis was 99% +/- 0.6%, the freedom from paravalvular leak was 96% +/- 1.5%, the freedom from all valve-related complications was 78% +/- 4.5%, and the freedom from structural valve deterioration was 95% +/- 3.7%. At 8 years, the actuarial freedom from structural valve deterioration was 89% +/- 10% and 95.8% +/- 4% in patients younger and older than 65 years, respectively. At 10 years, in patients older than 65 years, the actual freedom from structural valve deterioration was 97.9% +/- 2.1%, and the freedom from reoperation was 97% +/- 1.3%. New York Heart Association status was I or II in 90% of patients at the end of follow-up. The mean echocardiographic follow-up time was 4.6 +/- 2 years. By using Doppler echocardiography, the peak and mean transprosthetic gradients were determined to be 30.8 +/- 9.3 mm Hg and 16.6 +/- 5.3 mm Hg, respectively. Mean mass/volume ratio and left ventricular end-diastolic volume were 1.37 +/- 0.17 g/mL and 63.4 +/- 22.6 mL/m(2), respectively. The majority of patients showed a persistent left ventricular hypertrophy.

CONCLUSION

The Biocor is an effective bioprosthesis with a low incidence of valve-related complications comparable with that of other second-generation bioprostheses. This stented porcine prosthesis provides satisfactory results in terms of hemodynamics, valve durability, and freedom from reoperation.

Prosthesis size and long-term survival after aortic valve replacement

OBJECTIVE

This study was undertaken to quantify the relationship between prosthesis size adjusted for patient size (prosthesis-patient size) and long-term survival after aortic valve replacement.

METHODS

Data from nine representative sources on 13,258 aortic valve replacements provided 69,780 patient-years of follow-up (mean 5.3 +/- 4.7 years), with reliable survival estimates to 15 years. Prostheses included 5757 stented porcine xenografts, 3198 stented bovine pericardial xenografts, 3583 mechanical valves, and 720 allografts. Manufacturers' labeled prosthesis size was 19 mm or smaller in 1109 patients. Expressions of prosthesis-patient size assessed were indexed internal prosthesis orifice area (in centimeters squared per square meter of body surface area) and standardized internal prosthesis orifice size (Z, the number of SDs from mean normal native aortic valve size). Multivariable hazard domain analysis with balancing score and risk factor adjustment quantified the association of prosthesis-patient size with survival.

RESULTS

Prosthesis-patient size down to at least 1.1 cm(2)/m(2) or -3 Z did not adversely affect intermediate- or long-term survival (P >.2). However, 30-day mortality increased 1% to 2% when indexed orifice area fell below 1.2 cm(2)/m(2) (P =.002) or standardized orifice size fell below -2.5 Z (P =.0003). The increased early risk affected fewer than 1% of patients receiving bioprostheses but about 25% of those receiving mechanical devices.

CONCLUSIONS

Aortic prosthesis-patient size down to 1.1 cm(2)/m(2) or -3 Z did not reduce intermediate- or long-term survival after aortic valve replacement. However, patient-prosthesis size under 1.2 cm(2)/m(2) or -2.5 Z was associated with a 1% to 2% increase in 30-day mortality. Prosthesis-patient sizes this small or smaller were rarely implanted in patients receiving bioprostheses.

Choice of prosthetic heart valve for adult patients

This review summarizes the major long-term (> or =10 to 15 years) patient outcomes after insertion of many Food and Drug Administration approved prosthetic heart valves (PHV). Mechanical PHV was associated with a better survival (p < 0.02) at 15 years after aortic valve replacement (AVR) than with a bioprosthesis in the Department of Veterans Affairs (DVA) trial. In both the DVA and the Edinburgh Heart Valve trials, bioprosthesis were associated with structural valve deterioration (SVD) (mitral valve replacement [MVR] > AVR) and, therefore, for replacement of the PHV. Thromboembolism and bleeding rate were higher with mechanical PHV. Mortality after AVR and MVR is high at 10 to 15 years because of the associated comorbid conditions and older age of patients. Outcomes with "new" good valves are similar to that with "older" good valves. Complication rates of thromboembolism, bleeding, endocarditis, and leak vary widely; the rates of these complications are not different among different mechanical PHV and among different bioprosthetic PHV. Structural valve deterioration is rare with mechanical PHV. Structural valve deterioration of bioprosthesis after MVR is higher than after AVR; after AVR, homografts and bioprosthesis have similar rates of SVD. The exact rate of SVD of the pulmonary autograft is uncertain. Valve prosthesis-patient mismatch is clinically important when it is severe and in selected patients when it is moderate. Bioprosthesis have a low rate of SVD in the older patient and, thus, are the PHV of choice for AVR in patients > or =60 to 65 years of age and for MVR in patients > or =65 to 70 years of age; in younger patients mechanical valves are the PHV of choice. In individual patients there may be exceptions to these general rules.

Usefulness of the Cryolife O'Brien stentless suprannular aortic valve to prevent prosthesis-patient mismatch in the small aortic root

OBJECTIVES

This study evaluated the occurrence of prosthesis-patient mismatch (PPM) after Cryolife O'Brien (CLOB) suprannular stentless valve replacement in patients with a small aortic root and its repercussions on the patient's hemodynamic status and left ventricular mass regression.

BACKGROUND

The correct management of the small aortic annulus is still controversial. Small aortic prostheses can lead to a PPM, which results in high gradients with important repercussions on the hemodynamic status.

METHODS

Seventy-two patients (mean age: 72.5 +/- 6.2 years, 73.6% women) with a small aortic root (< or =21 mm intraoperatively measured aortic annulus) had a CLOB valve implanted in the aortic position between November 1993 and July 2001 at our institution. Mean prosthesis size was 22.0 +/- 0.8 mm. Patients underwent echocardiography preoperatively, at discharge, six months, one year and yearly thereafter.

RESULTS

The incidence of PPM at discharge was 22.2% (16/72); 18.7% were severe (effective orifice area index [EOAI] < or =0.65 cm/m(2)), 43.7% were moderate (EOAI = 0.66 to 0.75 cm/m(2)) and 37.6% were mild (0.76 to 0.85 cm/m(2)). At multivariable analysis, gender (p < 0.001), age (p = 0.015), body surface area (p < 0.001) and patient's annulus index (p < 0.001) were significant factors influencing the occurrence of "transient" PPM. At one year the incidence of PPM was 0%. CONCLUSIONS; Suprannular CLOB valve yielded excellent hemodynamic results in patients with small aortic roots. This study demonstrates that PPM can be completely avoided when using the CLOB valve. The superior hemodynamics of this stentless valve are likely to be related to its suprannular design.

Patient prosthesis mismatch is rare after aortic valve replacement: valve size may be irrelevant

BACKGROUND

Although small valve size and patient-prosthesis mismatch are both considered to decrease long-term survival, little direct evidence exists to support this hypothesis.

METHODS

To assess the prevalence of patient-prosthesis mismatch and the influence of small valve size on survival, we prospectively studied 1,129 consecutive patients undergoing aortic valve replacement between 1990 and 2000. Mean and peak gradients and indexed effective orifice area were measured by transthoracic echocardiography postoperatively (3 months to 10 years). Abnormal postoperative gradients were defined as those patients with mean or peak gradient above the 90th percentile (mean gradient > or = 21 or peak gradient > or = 38 mm Hg). Patient-prosthesis mismatch was defined as those patients with indexed effective orifice area below the 10th percentile (< 0.60 cm2/m2).

RESULTS

A multivariable analysis identified internal diameter of the implanted valve as the only independent predictor of abnormal gradients postoperatively. However, there was no significant difference in actuarial survival between normal and abnormal gradient groups (7 years: 91.2% +/- 1.5% versus 95.0% +/- 2.2%; p = 0.48). Freedom from New York Heart Association class III or IV (7 years: 74.5% +/- 3.1% versus 74.6% +/- 6.2%; p = 0.66) and left ventricular mass index were not different between normal and abnormal gradient groups. Patients with and without patient-prosthesis mismatch were similar with respect to postoperative left ventricular mass index, 7-year survival (95.1% +/- 1.3% versus 94.7% +/- 3.0%; p = 0.54), and 7-year freedom from New York Heart Association class III or IV (79.3% +/- 6.6% versus 74.5% +/- 2.5%; p = 0.40). In patients with patient-prosthesis mismatch and abnormal gradients, the majority had prosthesis dysfunction owing to degeneration.

CONCLUSIONS

Severe patient-prosthesis mismatch is rare after aortic valve replacement. Patient-prosthesis mismatch, abnormal gradient, and the size of valve implanted do not influence left ventricular mass index or intermediate-term survival.

Complete aortic root replacement in patients with small aortic annulus

BACKGROUND

We evaluated the effectiveness of our surgical method using a modified self-assembled valved composite graft in patients with a narrow aortic annulus.

METHODS

Between August 2000 and May 2001, 10 consecutive patients with a narrow aortic annulus underwent replacement of the aortic valve and the ascending aorta using a valved composite graft with mechanical valve prosthesis. The indication for surgery was aneurysm of the ascending aorta (8 patients) and aortic dissection (2 patients). To avoid valve-patient mismatch, a modified self-assembled valved composite graft was used.

RESULTS

There was no hospital mortality. Echocardiographic evaluation before discharge showed excellent hemodynamics with a mean transvalvular gradient of 10.7 mm Hg (standard deviation +/- 2.8 mm Hg).

CONCLUSIONS

The described valved composite graft offers very good hemodynamic performance and is a simple and effective device to avoid valve-patient mismatch in patients with a small aortic annulus who need aortic root replacement.

Are stentless valves hemodynamically superior to stented valves? A prospective randomized trial

BACKGROUND

Although stentless aortic bioprostheses are believed to offer improved outcomes, hemodynamic benefits remain unsubstantiated.

METHODS

Fifty-three patients were randomized to receive the stented C-E pericardial valve (CE) and 46 patients the Toronto Stentless Porcine valve (SPV). Annuli were sized for the optimal insertion of both valve types, such that surgeons were required to commit to specific valve sizes before randomization. Echocardiographic measurements and functional status (Duke Activity Status Index) were assessed at 3 and 12 months postoperatively.

RESULTS

Although cardiopulmonary bypass times (CE: 118.6+/-36.3 minutes; SPV: 148.5+/-30.9 minutes; p = 0.0001) and aortic cross-clamp times (CE: 95.4+/-28.6 minutes; SPV: 123.6+/-24.1 minutes; p = 0.0001) were significantly prolonged in the SPV group, perioperative morbidity and mortality was similar between groups. Neither valve offered a superior internal diameter for any given annular diameter (mean decrease in left ventricular outflow tract diameter after valvular implantation: SPV: 3.4+/-1.11 mm versus CE: 3.7+/-1.33 mm; p = 0.25). Although labeled mean valve size was significantly larger in the SPV group, the actual mean valve size based on internal valvular diameter was no different between groups (CE: 21.9+/-2.0 mm; SPV: 22.3+/-2.0 mm; p = 0.286). Although effective orifice areas increased, and mean and peak transvalvular gradients decreased in both groups over time, no differences were demonstrated between groups at 12 months. Similarly, although significant regression of left ventricular mass was accomplished in both groups over time, no differences were demonstrated between groups. Finally, Duke Activity Status Index scores of functional status improved in both groups over time; however, no differences were noted between groups at 12 months postoperatively.

CONCLUSIONS

Although offering excellent outcomes, stentless valves did not demonstrate superior hemodynamic indices in comparison to stented valves up to 12 months after implantation.

Clinical outcome in patients with 19-mm and 21-mm St. Jude aortic prostheses: comparison at long-term follow-up

BACKGROUND

Small-sized prostheses for aortic valve replacement may result in residual left ventricular outflow tract obstruction. Aim of the study was to verify whether implantation of 19-mm versus 21-mm St. Jude Medical standard prostheses (St. Jude Medical, Inc, St. Paul, MN) influences long-term clinical outcome.

METHODS

Two hundred twenty-nine patients who underwent aortic valve replacement with 19 mm (group 1, 53 patients) or 21-mm St. Jude Medical standard prostheses (group 2, 176 patients) were included in the study. Mean follow-up of current survivors was 10+/-4 years.

RESULTS

Operative mortality was 7.5% in group 1 and 8.5% in group 2. At discharge, an important patient-prosthesis mismatch (effective orifice area index < or = 0.60 cm2/m2) was present in 18% of group 1 versus 5% in group 2 (p = 0.004). Among patients with body surface area less than 1.70 m2, such mismatch was present in 15% of group 1 versus 2% of group 2 (p = 0.008). At last follow-up New York Heart Association (NYHA) functional class (p < 0.001), left ventricular mass reduction (p = 0.02), mean (p = 0.002) and peak transprosthetic gradients (p < 0.001), and effective orifice area index (p = 0.005) were significantly better in group 2. Freedom from sudden death (92%+/-5% vs 99%+/-1%, p = 0.01), valve-related death (84%+/-6% vs 90%+/-5%, p = 0.02), and cardiac events (56%+/-13% vs 86%+/-4%, p = 0.008), were significantly lower in group 1. Effective orifice area index was an independent predictor of late cardiac events.

CONCLUSIONS

Although long-term results after aortic valve replacement with small-sized St. Jude Medical standard prostheses are satisfactory, 19-mm valve recipients show a high prevalence of important patient-prosthesis mismatch with less evident functional improvement and higher rate of cardiac events, suggesting a very cautious use of this prosthesis.

Exercise hemodynamics of aortic prostheses: comparison between stentless bioprostheses and mechanical valves

BACKGROUND

Nonstented bioprostheses have been associated with lower resting gradients than stented bioprostheses or mechanical valves. We compared the hemodynamic performance of nonstented bioprostheses and mechanical valves with normal native aortic valves at rest and exercise.

METHODS

Dobutamine echocardiography was used to assess gradients and effective orifice area index at rest and exercise in patients with the Toronto stentless porcine valve (TSPV; n = 13; mean implant size 25.7 mm), Medtronic Freestyle (FR; n = 11; mean implant size 23.9 mm), Sorin Bicarbon (SOR; n = 11; mean implant size 24.5 mm), St. Jude Medical (SJM; n = 10; mean implant size 21.3 mm), and normal native aortic valves (NOR; n = 10).

RESULTS

All groups demonstrated a major rise in cardiac output at maximal dobutamine infusion. At rest and exercise, respectively, mean gradients were 5.48 +/- 1.1 mm Hg and 5.83 +/- 0.9 mm Hg for TSPV, 5.68 +/- 1.2 mm Hg and 7.50 +/- 1.7 mm Hg for FR, 10.29 +/- 1.4 mm Hg and 20.78 +/- 2.7 mm Hg for SJM, 5.26 +/- 0.8 mm Hg and 11.1 +/- 1.8 mm Hg for SOR, and 1.54 +/- 0.4 mm Hg and 2.18 +/- 0.7 mm Hg for NOR. In comparison with normal valves, both stentless groups showed no change in mean gradient at exercise, whereas both mechanical groups showed an increase in gradient at exercise (p < 0.04).

CONCLUSIONS

Stentless valves behave similarly to normal aortic valves in that there is almost no increase in gradient at exercise. Both mechanical valve groups showed increased gradients at exercise, suggesting that these valves obstruct blood flow. Our data add further evidence that stentless valves are hemodynamically superior to mechanical valves in the aortic position.

Standard versus hemodynamic plus 19-mm St Jude Medical aortic valves

OBJECTIVE

We reviewed our experience with aortic valve replacement using 19-mm St Jude Medical prostheses (St Jude Medical, Inc, St Paul, Minn) in 119 patients, among which 68 (group A) had a Standard model and 51 (group B) had a Hemodynamic Plus model.

METHODS

Comparison between the 2 models included analysis of early and late mortality and all valve-related complications. Postoperative echocardiography was performed to evaluate the hemodynamic performance of both prosthetic models. Laboratory tests were performed to evaluate the amount of red blood cell damage caused by the transprosthetic turbulent flow.

RESULTS

Average body surface area was 1.66 +/- 0.14 m(2) in group A and 1.65 +/- 0.16 m(2) in group B (P =.72). There was no statistically significant difference between the 2 groups in terms of preoperative variables (sex, cardiac rhythm, body surface area, preoperative gradients, and New York Heart Association class). Five-year follow-up was 100% complete. Although group A patients had significantly higher postoperative peak and mean gradients (P =.0001) and a lower effective orifice area (P =.0001), no statistical differences were found in terms of late (5-year) survival (P =.6) and postoperative complications (P =.09). Moreover, postoperative left ventricular mass was found to be similar in the 2 groups (P =.18). Hematologic evaluation did not show any significant difference between the 2 groups as to incidence of hemolysis.

CONCLUSIONS

Aortic valve replacement with 19-mm aortic prostheses in patients with a body surface area of less than 1.7 m(2) allows good results. Although Hemodynamic Plus models have better hemodynamic results, no significant difference was found in terms of clinical results and clinical hemolysis.

Outcome and follow-up of aortic valve replacement with the freestyle stentless bioprosthesis

BACKGROUND

The aim of this study was to determine the morbidity, mortality, and hemodynamics after implantation of the Freestyle stentless bioprosthesis in the aortic position.

METHODS

A total of 280 patients were operated on from June 1993 to July 1999 as part of a multicenter investigation. Factors influencing hospital mortality and long-term survival were assessed by logistic regression and Cox proportional hazards analysis. Patients were evaluated postoperatively at discharge, at 3 to 6 months, and yearly by clinical examination and color flow Doppler echocardiography.

RESULTS

Hospital mortality in this group was relatively high (9.6%). Logistic regression analysis showed that cross-clamp time, age, myocardial infarction, diabetes, left ventricular hypertrophy, coronary artery disease, New York Heart Association class III or IV and female gender were the independent predictive factors. According to the Kaplan-Meier method, the 4-year survival for hospital survivors was 94%. In the multivariate Cox proportional hazard analysis, only coronary artery disease proved to be prognostic. During follow-up, 11 patients developed paravalvular leakage due to prosthetic dehiscence at the side of the noncoronary cusp. Performance of the prosthesis as assessed by echocardiography was excellent. Mean gradient decreased significantly between discharge and follow-up at 3 to 6 months. At 1-year follow-up trivial regurgitation was found in 6 patients (3%) and mild regurgitation in 4 (2%). Regurgitation did not increase with time. The effective orifice area increased significantly from discharge to follow-up at 3 to 6 months.

CONCLUSIONS

Hospital mortality after implantation of a stentless bioprosthesis was higher compared to conventional prosthesis. A high incidence of prosthesis dehiscence at the proximal suture line was found, which was probably due to technique. Hemodynamic performance up to 3 years showed low transvalvular gradients. There is echocardiographic evidence for reduction of left ventricular hypertrophy and improvement of left ventricular function.

Aortic valve replacement in geriatric patients: determinants of in-hospital mortality

BACKGROUND

Aortic valve replacement is a common procedure in elderly patients. There has been a great deal of controversy about the risks associated with early mortality. Uncertainty of the risk associated with a small valve continues to remain controversial. This study was designed to identify the risk factors influencing early mortality and establish an accurate model for the prediction of in-hospital mortality.

METHODS

One hundred eighty septuagenarians and octogenarians (58% women; mean age, 76 +/- 4.7 years) underwent primary isolated aortic valve replacement between 1986 and 1997. There was an overall mortality of 16.7% (n = 180). Patients with a body surface area less than 1.8 m2 had an in-hospital mortality of 23.2% (n = 95) compared with 8.1% (n = 74; p = 0.009) for patients with a body surface area of 1.8 m2 or more. Patients with a cardiopulmonary bypass time of less than 100 minutes experienced an early mortality of 8.9% (n = 56) compared with a 10.2% (n = 59) early mortality for patients on bypass time between 100 and 124 minutes and a 29.6% (n = 64) early mortality in patients with a pump time longer than 124 minutes (p = 0.040).

RESULTS

Multivariate logistic regression analysis identified small body surface area and long cardiopulmonary bypass time as independent risk factors. A higher mortality was seen in female patients and patients receiving smaller valves. However, there was a strong correlation between small body surface area, small valve size, and female gender.

CONCLUSIONS

Small body surface area and long cardiopulmonary bypass time are two independent risk factors in early mortality for elderly patients undergoing primary isolated aortic valve replacement. The use of small valves does not influence early mortality.

The CryoLife O'Brien stentless porcine aortic bioprosthesis: 5-year follow-up

BACKGROUND

Mortality, morbidity, complication rates, and echo hemodynamic results using the Cryolife O'Brien stentless aortic bioprosthesis over a 5-year period are reported.

METHODS

The stentless valve was implanted in 97 conscecutive patients, 54 male and 43 female, mean age 70.9 +/- 6.5 years. All patients underwent preoperative, discharge (early study), 6-month (intermediate study), and late (18.3 +/- 10.4 months) echocardiography.

RESULTS

The actuarial 5-year survival rate was 93.9% +/- 3%. Aortic regurgitation was absent in 95.5%, mild in 3.4%, and moderate in 1.1%. Peak and mean systolic gradients were significantly lower at discharge (p < 0.001) and at the 6-month follow-up (p < 0.001) but did not significantly fall further at the late study (p = NS). The effective orifice area index at discharge (p < 0.001) and at 6 months (p < 0.001) differed significantly from preoperative values, but variations at late study were not significant (p = NS). Left ventricular mass index decreased early postoperatively (p < 0.001) and at 6-month assessment (p < 0.001) with a further significant reduction at late echocardiography (p = 0.04).

CONCLUSIONS

The 5-year results of this stentless valve showed a low rate of valve-related complications with excellent hemodynamic performance in all valve sizes.

Prosthesis-Patient Mismatch Affects Survival After Aortic Valve Replacement

Background —Surgeons traditionally avoid the use of “small” aortic prostheses because of the potential for residual left ventricular outflow tract obstruction and persistent transvalvular gradients. This study examines the ratio between prosthetic valve size and the body surface area (BSA) of patients undergoing aortic valve replacement (AVR). We sought to determine the effect of potential “prosthesis-patient” mismatch on long-term survival.

Methods and Results —Follow-up was conducted on 2981 patients who underwent AVR with stented bioprostheses between 1976 and 1996. To account for differences between manufacturers’ labeled valve sizes, we calculated the ratio between the prosthetic valve effective orifice area (EOA) and the patient’s BSA (recorded for 2154 patients). The lowest decile in this cohort had a calculated EOA/BSA of <0.75 cm 2 /m 2 (Small group, n=227) compared with the control group (n=1927), in whom the EOA/BSA ratio was >0.75 cm 2 /m 2 . Operative mortality was higher in the Small group (8% versus 5%, P =0.03). Actuarial survival at 12 years was 50±5% in the Small group compared with 49±2% in the control group ( P =0.27). However, freedom from valve-related mortality was significantly lower in the Small group (75±5% versus 84±2%, P =0.004). Cox regression analysis determined age and NYHA functional class to be the multivariate predictors of overall mortality, whereas advanced age and EOA/BSA <0.75 cm 2 /m 2 were found to be the predictors of valve-related mortality.

Conclusions —Prosthesis-patient mismatch results in significantly higher early and late mortality after bioprosthetic AVR. We recommend careful selection of stented bioprostheses to ensure an adequate ratio of EOA to BSA. An EOA/BSA ratio of >0.75 cm 2 /m 2 may avoid residual left ventricular outflow tract obstruction and persistent transvalvular gradients. Careful prosthesis-patient matching will improve both early and late survival after AVR.

Aortic valve replacement: is valve size important?

OBJECTIVE

We sought to determine whether aortic prosthesis size adversely influences survival after aortic valve replacement.

METHODS

A total of 892 adults receiving a mechanical (n = 346), pericardial (n = 463), or allograft (n = 83) valve for aortic stenosis were observed for up to 20 years (mean, 5.0 +/- 3.9 years) after primary isolated aortic valve replacement. We used multivariable propensity scores to adjust for valve selection factors, multivariable hazard function analyses to identify risk factors for all-cause mortality, and bootstrap resampling to quantify the reliability of the results.

RESULTS

Twenty-five percent of patients had indexed internal orifice areas of less than 1.5 cm(2)/m(2) and more than 2 SDs (Z-value) below predicted normal aortic valve size. Mechanical valve orifices were smaller (1.3 +/- 0. 29 cm(2)/m(2), Z = -2.2 +/- 1.16) than pericardial (1.9 +/- 0.36 cm(2)/m(2), Z = -0.40 +/- 1.01) or allograft valves (2.1 +/- 0.50, Z = 0.24 +/- 1.17). The overall survival was 98%, 96%, 86%, 69%, and 49% at 30 days and 1, 5, 10, and 15 years postoperatively. Univariably, survival was weakly and inversely related to manufacturer valve size (P =.16) and internal orifice diameter (P =. 2) but completely unrelated to indexed valve area (P =.6) or Z-value (P =.8). These, and univariable differences among valve types (P =. 004), were accounted for by different prevalences in patient risk factors and not by valve size or type per se. Bootstrap resampling indicated that these findings had a less than 15% chance of being incorrect.

CONCLUSIONS

Survival after aortic valve replacement is strongly related to patient risk factors but appears not to be adversely affected by moderate patient-prosthesis mismatch (down to about 4 SDs below normal). Aortic root enlargement to accommodate a large prosthesis may be required in few situations.