Effects of valve substitute on changes in left ventricular function and hypertrophy after aortic valve replacement

Hemodynamic Comparison of the On-X and Top Hat Mechanical Aortic Valve Prostheses

BACKGROUND

There are limited data comparing hemodynamic valve function in mechanical aortic valve prostheses. This study compared the hemodynamic function of 2 commonly used mechanical aortic valve (AV) prostheses, the On-X (Artivion) and Top Hat (CarboMedics Inc) valves.

METHODS

This study was a retrospective analysis of 512 patients who underwent AV replacement with the On-X (n = 252; 49%) or Top Hat (n = 260; 51%) mechanical valves between 2011 and 2019. Patients were matched on the basis of selected variables. Echocardiographic data were collected preoperatively and postoperatively over a median follow-up of 1.39 years.

RESULTS

A total of 320 patients were matched, 160 patients in each group. Despite being matched for left ventricular outflow tract diameter, patients in the Top Hat group received a greater prevalence of smaller tissue annulus diameter valves (≤21 mm) (83% vs 38%; P < .001). Patients in the On-X group had longer aortic cross-clamp times (78 minutes vs 64 minutes; P < .001) during isolated aortic valve replacement. Discharge echocardiography showed no difference in the AV area index between both groups (1.00 cm2/m2 vs 1.02 cm2/m2; P = .377). During longer-term echocardiographic follow-up, the AV area index remained stable for both valves within their respective tissue annulus diameter groups (P = .060).

CONCLUSIONS

There was no difference between the 2 valves with respect to the AV area index at discharge, and hemodynamic function was stable during longer-term follow-up. The longer aortic cross-clamp time observed in the On-X group may indicate increased complexity of implantation compared with the Top Hat group.

Left Ventricular Reverse Remodeling after Surgical Aortic Valve Replacement for Aortic Regurgitation-An Explorative Study

BACKGROUND

The timing of treatment for chronic aortic valve regurgitation (AR), especially in asymptomatic patients, is gaining attention since less invasive strategies have become available. The aim of the present study was to evaluate left ventricular reverse remodeling after aortic valve replacement (AVR) for severe AR.

METHODS

Patients (n = 25) who underwent surgical AVR for severe AR with left ventricular ejection fraction (LVEF) less than 55% were included in this study. Preprocedural and follow-up clinical and echocardiographic measurements of LVEF and left ventricular (LV) diameters were retrospectively analyzed.

RESULTS

Mean LVEF increased significantly following surgical AVR (p < 0.0001). LV diameters showed a clear regression (p = 0.0088). Younger patients and those receiving a mechanical valve tended to have less improved LVEF on follow-up than patients over 60 years or the ones who were implanted with a biological prosthesis (p = 0.0239 and p = 0.069, respectively). Gender had no effect on the degree of LVEF improvement (p = 0.4908).

CONCLUSIONS

We demonstrated significant LV reverse remodeling following AVR for AR. However, more data are needed on LV functional and geometrical improvement comparing the different types of valve prostheses to provide an optimal treatment strategy.

Heart failure and excess mortality after aortic valve replacement in aortic stenosis

INTRODUCTION

In aortic stenosis (AS), the heart transitions from adaptive compensation to an AS cardiomyopathy and eventually leads to decompensation with heart failure. Better understanding of the underpinning pathophysiological mechanisms is required in order to inform strategies to prevent decompensation.

AREAS COVERED

In this review, we therefore aim to appraise the current pathophysiological understanding of adaptive and maladaptive processes in AS, appraise potential avenues of adjunctive therapy before or after AVR and highlight areas of further research in the management of heart failure post AVR.

EXPERT OPINION

Tailored strategies for the timing of intervention accounting for individual patient's response to the afterload insult are underway, and promise to guide better management in the future. Further clinical trials of adjunctive pharmacological and device therapy to either cardioprotect prior to intervention or promote reverse remodeling and recovery after intervention are needed to mitigate the risk of heart failure and excess mortality.

Midterm Outcomes of Stented Versus Stentless Bioprosthetic Valves After Aortic Root Replacement

To determine the impact of aortic root replacement (ARR) with a stentless bioprosthetic valve on midterm outcomes compared to a stented bioprosthetic valve-graft conduit. This was an observational study of aortic root operations from 2010 to 2018. All patients with a complete ARR for nonendocarditis reasons were included, while patients undergoing valve-sparing root replacements or primary aortic valve replacement or repair were excluded. Of the patients with a complete ARR, bioprosthetic valve implants were included, while mechanical valve implants were excluded. Patients were dichotomized into the stented ARR group and the stentless ARR group. A total of 1:1 nearest neighbor propensity matching was employed to assess the association of stentless valves with short-term and midterm outcomes. A total of 455 patients underwent a complete ARR with a bioprosthetic valve implant for nonendocarditis reasons, of which 212 (46.6%) received a stented valve, while 243 (53.4%) received a stentless valve. After matching, postoperative outcomes were similar across each group (P > 0.05), including operative mortality and adverse neurologic events. Median follow-up for the entire cohort was 4.41 years (95% CI: 4.01, 4.95). At 1 year follow-up, aortic regurgitation ≥ 2+ and ejection fraction were similar across each group (P > 0.05); however, the stentless valve group had lower aortic valve velocity and transvalvular pressure gradient. Finally, reoperations and survival were similar for each group over the study's follow-up (P > 0.05). Stentless valves may provide hemodynamic benefits after ARR; however, the clinical impact of those benefits for survival and reoperation may not yet be evident in the midterm.

Challenges and opportunities in improving left ventricular remodelling and clinical outcome following surgical and trans-catheter aortic valve replacement

Over the last half century, surgical aortic valve replacement (SAVR) has evolved to offer a durable and efficient valve haemodynamically, with low procedural complications that allows favourable remodelling of left ventricular (LV) structure and function. The latter has become more challenging among elderly patients, particularly following trans-catheter aortic valve implantation (TAVI). Precise understanding of myocardial adaptation to pressure and volume overloading and its responses to valve surgery requires comprehensive assessments from aortic valve energy loss, valvular-vascular impedance to myocardial activation, force-velocity relationship, and myocardial strain. LV hypertrophy and myocardial fibrosis remains as the structural and morphological focus in this endeavour. Early intervention in asymptomatic aortic stenosis or regurgitation along with individualised management of hypertension and atrial fibrillation is likely to improve patient outcome. Physiological pacing via the His-Purkinje system for conduction abnormalities, further reduction in para-valvular aortic regurgitation along with therapy of angiotensin receptor blockade will improve patient outcome by facilitating hypertrophy regression, LV coordinate contraction, and global vascular function. TAVI leaflet thromboses require anticoagulation while impaired access to coronary ostia risks future TAVI-in-TAVI or coronary interventions. Until comparable long-term durability and the resolution of TAVI related complications become available, SAVR remains the first choice for lower risk younger patients.

Speckle tracking echocardiography in severe patient-prosthesis mismatch

BACKGROUND

Although aortic valve replacement (AVR) when successfully performed boasts low mortality rates in selected patients, prosthesis-patient mismatch (PPM) can be found in the majority of these individuals. Limited research is available supporting the benefit of two-dimensional speckle tracking echocardiography (2D-STE) in patients with severe PPM. This study sought to assess myocardial strain using 2D-STE to determine the relationship between subclinical left ventricular (LV) dysfunction and aortic PPM in patients undergoing AVR with preserved LV ejection fraction.

MATERIAL AND METHODS

We retrospectively examined all consecutive patients with isolated AVR who presented to our center from 2005 to 2018. The data of 1086 patients were analyzed. Severe PPM was defined as an indexed effective orifice area of 0.65 cm²/m² or less. As a result of the detailed assessment, 54 patients meeting the eligibility criteria were included in the study. Baseline data were collected and compared between the two groups of patients with severe PPM (n = 27) and those with normofunctional aortic prosthesis valve as a control group (n = 27). All patients underwent baseline echocardiography. Global longitudinal strain (GLS) and global circumferential strain (GCS) were evaluated by 2D-STE.

RESULTS

When compared with controls, patients with severe PPM had significantly decreased GLS (18.6 ± 2.9 vs. 21.4 ± 2.1; p < 0.01) and GCS (17.2 ± 3.6 vs. 21.7 ± 2.1; p < 0.01) values.

CONCLUSION

In addition to standard clinical and echocardiographic parameters, GLS and GCS suggest subclinical dysfunction and have incremental value in patients with severe PPM.

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 (LVMi) 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 LVMi 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.

Those who do not remember the past are condemned to repeat it

Transcatheter aortic valve replacement (TAVR) for aortic valve stenosis has rapidly progressed from its initial application in the inoperable or high-risk patients to those determined to be intermediate and low risk. It is our concern this has occurred without adequate knowledge or examination of the long-term durability of TAVR valves and the impact on subsequent aortic valve surgery, should it be required. In this editorial, we provide insight and reflect upon lessons learned from past surgical techniques and their subsequent abandonment.

Sex Differences in Aortic Stenosis and Outcome Following Surgical and Transcatheter Aortic Valve Replacement

Aortic stenosis is the commonest valve defect in the developed world and is associated with a high mortality once symptomatic. There is a difference in the way that male and female hearts remodel in the face of chronic pressure overload: women develop a concentrically hypertrophied, small cavity left ventricle (LV), whereas men are more prone to the development of eccentric hypertrophy. At a cellular level, there is an increase in collagen and metalloproteinase gene expression in males suggesting a different regulation of extracellular volume composition according to sex. Male hearts with aortic stenosis appear to have more fibrosis than their female comparators. The trigger for this appears to be in part related to estrogen receptor signaling, but other factors such as renin-angiotensin activation, nitric oxide, and circulating noradrenaline levels may also be implicated. Treatment options include surgical valve replacement (SAVR) and more recently transcatheter aortic valve replacement (TAVR). Female sex may be a risk factor for adverse outcome following SAVR and conversely appears to confer a survival advantage when undergoing TAVR. Whether the lower mortality seen following TAVR in women compared with men (despite their increased age and frailty) reflects their longer life expectancy, smaller annular size (and less post-TAVR aortic regurgitation), more favorable LV reverse remodeling, or more likely, a combination of these factors remains to be established.

Left ventricular hypertrophy in valvular aortic stenosis: mechanisms and clinical implications

Valvular aortic stenosis is the second most prevalent adult valve disease in the United States and causes progressive pressure overload, invariably leading to life-threatening complications. Surgical aortic valve replacement and, more recently, transcatheter aortic valve replacement effectively relieve the hemodynamic burden and improve the symptoms and survival of affected individuals. However, according to current American College of Cardiology/American Heart Association guidelines on the management of valvular heart disease, the indications for aortic valve replacement, including transcatheter aortic valve replacement, are based primarily on the development of clinical symptoms, because their presence indicates a dismal prognosis. Left ventricular hypertrophy develops in a sizeable proportion of patients before the onset of symptoms, and a growing body of literature demonstrates that regression of left ventricular hypertrophy resulting from aortic stenosis is incomplete after aortic valve replacement and associated with adverse early postoperative outcomes and worse long-term outcomes. Thus, reliance on the development of symptoms alone without consideration of structural abnormalities of the myocardium for optimal timing of aortic valve replacement potentially constitutes a missed opportunity to prevent postoperative morbidity and mortality from severe aortic stenosis, especially in the face of the quickly expanding indications of lower-risk transcatheter aortic valve replacement. The purpose of this review is to discuss the mechanisms and clinical implications of left ventricular hypertrophy in severe valvular aortic stenosis, which may eventually move to center stage as an indication for aortic valve replacement in the asymptomatic patient.

Hemodynamic performance of Trifecta: single-center experience of 400 patients

OBJECTIVE

To evaluate postoperative hemodynamic gradients and early outcomes of aortic valve replacement with the Trifecta bioprosthesis.

METHODS

Between 2011 and 2013, 400 patients underwent aortic valve replacement with a Trifecta bioprosthesis. Gradients were calculated by transthoracic echocardiography before discharge. Data were collected retrospectively; patients with postoperative severe left ventricular dysfunction or > mild mitral regurgitation were excluded.

RESULTS

The mean age was 75.9 ± 8.5 years, 197 (49.25%) patients were male, and 140 (35%) were >80-years old. Concomitant procedures were performed in 207 (51.75%) patients, and 30 (7.5%) had redo procedures. Supraannular aortoplasty with bovine pericardium was necessary in 25 (6.25%) cases. Hospital mortality was 2.75% (11 patients). Postoperative peak and mean gradients were 21.7 ± 9.3 and 11.1 ± 4.3 mm Hg for 19-mm valves (n = 29); 19.5 ± 7 and 9.7 ± 3.6 mm Hg for 21-mm valves (n = 158); 17.3 ± 6.6 and 8.7 ± 3.2 mm Hg for 23-mm valves (n = 134); 15.1 ± 6.1 and 7.8 ± 3.3 mm Hg for 25-mm valves (n = 56); 13.2 ± 3.7 and 6.9 ± 2.6 mm Hg for 27-mm valves (n = 11). Nine patients had trivial and one had mild transvalvular regurgitation. Mean follow-up was 1 ± 0.62 years; no patient required reoperation. Kaplan-Meier survival at 1 and 2 years was 94.3% ± 1.3% and 93.7% ± 1.4%.

CONCLUSION

Early postoperative gradients are low after Trifecta implantation. Significant transvalvular regurgitation was not observed, but the incidence of supraannular aortoplasty may be increased.

[Asymptomatic severe aortic stenosis: a reopened debate]

Aortic stenosis is a complex disease. About 2-7% of the population over 65 years of age is affected by its degenerative form. In patients with severe aortic stenosis presenting with symptoms or left ventricle ejection fraction (LVEF)<.50, aortic valve replacement is indicated. Management and timing of surgery in asymptomatic patients with preserved LVEF is still a matter of debate. Recent published data show that about one third of these patients present with low left ventricle stroke volume, which may affect survival. For this reason, and considering that aortic valve replacement is in most cases a low risk procedure, early surgery in this subgroup is a strategy that deserves to be taken into account. In this review we report on these recent findings, which allow understanding why patients with asymptomatic severe aortic stenosis should not be considered and treated as a homogenous population.

The novel two-dimensional strain reflects improvement and remodeling of left-ventricular function better than conventional echocardiographic parameters after aortic valve repair in pediatric patients

We aimed to evaluate the outcome and regional and global left-ventricular (LV) function after aortic valve repair in children with congenital aortic valve disease. Thirty-two consecutive patients with a mean age of 12.62 years (4 months to 18 years) undergoing aortic valve repair due to valve stenosis (AS group, n = 21) or aortic regurgitation (AR group, n = 11) were studied during a follow-up period of 12 months regarding change and adaptation of myocardial function using conventional and novel echocardiographic methods, including two-dimensional (2D) strain echocardiogram. Conventional and 2D strain echocardiographic studies were performed and analyzed off-line using commercially available software (EchoPac 6.1.0, GE). Peak aortic valve gradient decreased from 62.04 ± 30.34 mmHg before surgery to 22.80 ± 14.13 mmHg 2 weeks after surgery and to 35.73 ± 22.11 mmHg 12 months after surgery (p = 0.01). The degree of AR decreased significantly to grade 0 in 20 children and to grade I in 12. There was a significant decrease of thickness of the interventricular septum (IVS) and posterior wall resulting in improvement of LV mass index (p = 0.007, p = 0.043, and p = 0.001, respectively). Significant decrease of myocardial thickness was found, especially in the IVS, in the AS group (p = 0.008), and a significant decrease in LV end-diastolic dimension (EDD) was found in the AR group (p = 0.007). 2D strain analysis showed that global peak strain, global systolic strain rate, and global early diastolic strain rates improved significantly for all patients during the study period after aortic valve repair (p < 0.001, p = 0.037, and p = 0.018, respectively). The global strain and strain rates correlated significantly to IVS thickness (r = 0.002 and r = 0.003, respectively), LV mass index (r = 0.02 and r = 0.015, respectively), and EDD (r = 0.26 and r = 0.005, respectively). Aortic valve repair surgery in pediatric patients results in improvement of global and regional systolic and diastolic LV parameters, which was better shown by 2D strain parameters rather than conventional echocardiographic parameters.

Midterm Follow-up after Cryopreserved Homograft Replacement in the Aortic Position

Background

The long-term results of homografts used in systemic circulation are controversial. We assessed the long-term results of using a cryopreserved homograft for an aortic root or aorta and its branch replacement.

Materials and Methods

From June 1995 to January 2010, 23 patients (male:female=15:8, 45.4±15.6 years) underwent a homograft replacement in the aortic position. The surgical techniques used were aortic root replacement in 15 patients and aortic graft interposition in 8 patients. Indications for the use of a homograft were systemic vasculitis (n=15) and complicated infection (n=8). The duration of clinical follow-up was 65±58 months.

Results

Early mortality occurred in 2 patients (8.7%). Perioperative complications included atrial arrhythmia (n=3), acute renal failure (n=3), and low cardiac output syndrome (n=2). Late mortality occurred in 6 patients (26.1%). The overall survival rates at 5 and 10 years were 66.3% and 59.6%, respectively. Six patients (28.6%) suffered from homograft-related complications.

Conclusion

Early results of homograft replacement in aortic position were favorable. However, close long-term follow-up is required due to the high rate of homograft-related events.

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.

Aortic reoperation after freestanding homograft and pulmonary autograft root replacement

BACKGROUND

Human allografts and pulmonary autografts offer many advantages as an aortic valve and root substitute. The progressive degeneration of the aortic allograft and the pulmonary autograft has been seen as an important disadvantage, and the need for a reoperation has been perceived as challenging and risky for the patients.

METHODS

Between March 1992 and October 2009, 53 consecutive patients (mean age 50 ± 13 years; 38 male), who had a previous aortic root replacement, underwent redo surgery for failure of the aortic homograft (n = 42) or the pulmonary autograft (n = 11). The median follow-up (available for 47 of 51 patients) was 44 months.

RESULTS

Structural valve deterioration was the main indication for reoperation on the homograft (86%), with an earlier presentation in patients who received homografts from donors more than 55 years old. Failure of the pulmonary autograft occurred primarily because of severe aortic regurgitation predominantly due to dilation of the autograft (n = 5) and autograft valve prolapse (n = 5). The total in-hospital mortality was 3.8% (n = 2). No deaths occurred among patients who previously underwent a Ross procedure. The course was complicated in 25 cases (48%). The cumulative 1-year, 5-year, and 8-year survival rates were 92%, 90%, and 77%, respectively. No late deaths were encountered after reoperation on the pulmonary autograft (maximum follow-up 218 months). Freedom from reoperation (excluding early in-hospital operation) for recurrent aortic valve or root pathology was 97% at 8 years.

CONCLUSIONS

Reoperation after freestanding homograft and pulmonary autograft root replacement can be accomplished safely. The total postoperative morbidity rate is still high.

Homograft implantation for aortic valve replacement since 15 years: results and follow-up

BACKGROUND

The use of homografts in aortic valve replacement is an alternative to other prostheses and has been established in our department for 15 years.

METHODS

Since 1992, 360 homografts (HG) have been implanted in adult patients (mean age 51.6 years, 72.8% male). Prospective follow-up was done on an annual basis.

RESULTS

Thirty-day mortality was 5.0% (n = 17); after 5, 10, and 15 years, survival was 88.3%, 84.6%, and 76.0%, respectively. Out of 39 late deaths, 11 were valve-related (10 HG infections, 1 aortic aneurysm). Freedom from reoperation was 99.4% 1 year after operation; after 5, 10, and 15 years it was 94.1%, 78.2%, and 67.3%, respectively. Indications for HG explantation were graft infections (n = 20), calcification (n = 16), regurgitation > grade II (n = 17), perforation (n = 8), and paravalvular leakage (n = 1). Eleven transitoric ischemic attacks, 2 strokes, and 1 cerebral bleeding event were recorded. In echocardiography, the transvalvular pressure gradient changed from 10.55 to 15.02 (P = .004), 19.9 mmHg (P = .056), and 37 mmHg (not applicable) after 5, 10, and 15 years, respectively. Mean HG regurgitation was grade 0.49 before discharge and increased to 1.0 (P < .001), 0.91, and 2.5 after 5, 10, and 15 years, respectively. Ejection fraction increased from 61.9% to 64% after 5 years and to 66% after 10 years (P = .021) and then decreased to 63.5% after 15 years.

CONCLUSIONS

Comparing HG with other valve prostheses, survival and graft durability seem to be confirmed. They are vulnerable to infections. The hemodynamic performance is good, and hemorrhagic or thrombo-embolic events are rare.

Impact of hypertension on left ventricular hypertrophy regression and exercise capacity in patients operated for aortic valve stenosis

OBJECTIVES

To assess the influence of concomitant hypertension on left ventricular hypertrophy regression and exercise capacity in patients operated for aortic stenosis.

DESIGN

We performed echocardiography 1 week, 6- and 18-month postoperatively in 78 patients, aged 70 (28-86) years, who received Medtronic Hall (33), Biocor (8), Carpentier-Edwards S.A.V. (14) and Freestyle (23) prosthetic valves for severe aortic stenosis. Forty nine patients participated in treadmill tests with ergospirometry at the 6- and 18-month visits.

RESULTS

Left ventricular mass index was comparably reduced in normotensive and hypertensive patients (34 vs. 40 g/m2 after 6 months, and 43 vs. 46 g/m2 after 18 months, ns). In multiple regression analysis, adjusting for baseline left ventricular mass index, larger reduction in left ventricular mass index was associated with younger age and having a Freestyle prosthesis, but not with gender or history of hypertension (multiple R2=0.68, p < 0.05). Exercise capacity assessed as peak oxygen uptake increased from early to late evaluation in normotensive patients (VO2max 24.27 vs. 27.08 ml/kg/min, p < 0.05) while remained unchanged in hypertensive patients (VO2max 22.2 vs. 21.1 ml/kg/min). In multiple regression analysis, higher improvement in exercise capacity was predicted by male gender, younger age and absence of hypertension, while no independent association was found with Freestyle prosthesis (multiple R2 = 0.37, p < 0.05).

CONCLUSIONS

In patients operated for aortic stenosis, concomitant hypertension is associated with lack of improvement in exercise capacity in spite of early left ventricular hypertrophy reduction comparable to what is found in normotensive patients.

Stentless versus Stented Bioprosthetic Aortic Valves

Objective

This meta-analysis sought to determine whether stentless bioprosthetic valves improve clinical and resource outcomes compared with stented valves in patients undergoing aortic valve replacement.

Methods

A comprehensive search was undertaken to identify all randomized and nonrandomized controlled trials comparing stentless to stented bioprosthetic valves in patients undergoing aortic valve replacement available up to March 2008. The primary outcomes were clinical and resource outcomes in randomized controlled trial (RCT). Secondary outcomes clinical and resource outcomes in nonrandomized controlled trial (non-RCT). Odds ratios (OR), weighted mean differences (WMD), or standardized mean differences and their 95% confidence intervals (CI) were analyzed as appropriate.

Results

Seventeen RCTs published in 23 articles involving 1317 patients, and 14 non-RCTs published in 18 articles involving 2485 patients were included in the meta-analysis. For the primary analysis of randomized trials, mortality for stentless versus stented valve groups did not differ at 30 days (OR 1.36, 95% CI 0.68–2.72), 1 year (OR 1.01, 95% CI 0.55–1.85), or 2 to 10 years follow-up (OR 0.82, 95% CI 0.50–1.33). Aggregate event rates for all-cause mortality at 30 days were 3.7% versus 2.9%, at 1 year were 5.5% versus 5.9% and at 2 to 10 years were 17% versus 19% for stentless versus stented valve groups, respectively. Stroke or neurologic complications did not differ between stentless (3.6%) and stented (4.0%) valve groups. Risk of prosthesis-patient mismatch was numerically lower in the stentless group (11.0% vs. 31.3%, OR 0.30, 95% CI 0.05–1.66), but this parameter was reported in few trials and did not reach statistical significance. Effective orifice area index was significantly greater for stentless aortic valve compared with stented valves at 30 days (WMD 0.12 cm2/m2), at 2 to 6 months (WMD 0.15 cm2/m2), and at 1 year (WMD 0.26 cm2/m2). Mean gradient at 1 month was significantly lower in the stentless valve group (WMD −6 mm Hg), at 2 to 6 month follow-up (WMD −4 mm Hg,), at 1 year follow-up (WMD −3 mm Hg) and up to 3 year follow-up (WMD −3 mm Hg) compared with the stented valve group. Although the left ventricular mass index was generally lower in the stentless group versus the stented valve group, the aggregate estimates of mean difference did not reach significance during any time period of follow-up (1 month, 2–6 months, 1 year, and 8 years).

Conclusions

Evidence from randomized trials shows that subcoronary stentless aortic valves improve hemodynamic parameters of effective orifice area index, mean gradient, and peak gradient over the short and long term. These improvements have not led to proven impact on patient morbidity, mortality, and resource-related outcomes; however, few trials reported on clinical outcomes beyond 1 year and definitive conclusions are not possible until sufficient evidence addresses longer-term effects.

Left ventricular mass regression following implantation of MIRA bileaflet valves in patients with severe aortic stenosis

The aim of this study was to evaluate the factors that determine the course of left ventricular mass regression in a homogeneous group of patients following aortic valve replacement by use of the mechanical Edwards MIRA bileaflet prosthesis. Furthermore, we examined if the 19-mm valve leads to an equally good outcome when compared with larger 21- and 23-mm valves. We included 79 patients (49 men) with a mean age of 65+/-9 years operated on for isolated aortic valve replacement with the MIRA valve prosthesis. The analyses included preoperative and postoperative echocardiograms during a follow-up of at least 18 months (995+/-439 days) after valve surgery. Indication for valve replacement was aortic stenosis in 59 and combined disease (aortic stenosis and regurgitation) in 20 patients. Concomitant coronary artery bypass grafting was performed in 28 patients. Left ventricular mass index declined from 155.6+/-47 g/m(2) to 128.8+/-35 g/m(2) (P<0.001) at final visit and normalized in 49% of the patients. Female sex and a preoperatively highly elevated left ventricular mass index were identified as risk factors for residual hypertrophy. However, age and valve size did not have a predictive value for completeness of left ventricular mass regression. This study supports the evidence that an extensive preoperative left ventricular hypertrophy results in an incomplete postoperative mass regression in patients with aortic bileaflet valves. It shows that the slightly elevated pressure gradient in MIRA 19-mm valves does not affect left ventricular mass regression.

Medium-term outcome of Toronto aortic valve replacement: single center experience

BACKGROUND AND AIMS

Long-term competence of any aortic prosthesis is critical to its clinical durability. Bioprosthetic valves, and in particular the stentless type have been proposed to offer superior haemodynamic profiles with consequent potential for superior left-ventricular mass regression. These benefits however are balanced by the potential longevity of the implanted valve. The aims of this study were to assess medium-term Toronto aortic valve function and its effect on left-ventricular function.

METHODS

Between 1992 and 1996 86 patients underwent Toronto aortic valve replacement for aortic valve disease and were followed up annually. Prospectively collected data was analyzed for all patients where detailed echocardiographic follow-up was available. Echocardiographic studies were analyzed at 2+/-0.6 and 6+/-1.4 years after valve replacement. Data collected included left-ventricular systolic and diastolic dimensions, fractional shortening and left-ventricular mass. In addition, data on aortic valve and root morphology, peak aortic velocities, time velocity integral, stroke volume and the mechanism of valve failure where relevant, were also collected.

RESULTS

Complete echocardiographic data were available for eighty-four patients, age 69+/-9 years, 62 male. Additional coronary artery bypass grafting was performed in 38% of patients. Twelve (14%) valves had failed during follow-up, 7 (8%) requiring re-operation. Valve failure was associated with morphologically bicuspid native aortic valve (9/12), and progressive dilatation of the aortic sinuses, sino-tubular junction and ascending aorta (11/12). Left-ventricular mass index remained high (184+/-75 g/m(2)) and did not continue to regress between early and medium-term follow-up (175.8+/-77 g/m(2)).

CONCLUSIONS

Although more than 90% of implanted Toronto aortic valves remained haemodynamically stable with low gradient at medium-term follow-up, young age and larger aortic dimensions in patients with valve failure suggest better outcome if used in the elderly with normal aortic root geometry.

Stentless valves versus stented bioprostheses at the aortic position: midterm results

OBJECTIVE

Our aim was to compare stentless and stented bioprostheses. Clinical outcomes, hemodynamic performance, and postoperative left ventricular mass regression were the principal outcomes assessed.

METHODS

Sixty-two patients were recruited for the study. Our protocol was to consider all patients older than 55 years for bioprostheses, and also younger patients were implanted with a bioprosthesis if they wanted to avoid anticoagulation. Patients selected for bioprostheses were randomly assigned to receive stentless (group A) and stented (group B) bioprostheses, depending on the treating unit. Patients in groups A and B were further divided into subgroups I and II based on left ventricular ejection fractions of 50% or greater and less than 50%, respectively.

RESULTS

At 18 +/- 3 months postoperatively, the effective orifice area was greater in group A versus group B. Left ventricular ejection fraction, left ventricular mass index, functional class, and mean gradient were similar in patients of subgroup I (left ventricular ejection fraction >50%) from both groups. However, there was a significant difference between all except mean gradient in patients of subgroup II (left ventricular ejection fraction <50%) from both groups. Also, in the patient subgroup implanted with valves of less than 19 mm (group A, 4 patients; group B, 3 patients), there was a significant difference in left ventricular mass index and mean gradient.

CONCLUSION

In patients with left ventricular impairment or a small aortic annulus, stentless bioprostheses might allow for greater improvement in left ventricular function postoperatively.

Echocardiographic Follow-Up after Implanting 17-mm Regent Mechanical Prostheses

The aim of this study was to evaluate midterm echocardiographic results and changes in quality of life after aortic valve replacement with 17-mm St. Jude Medical Regent mechanical prostheses in patients with aortic valve stenosis. The study population was 34 women and 2 men, aged 31–83 years. Echocardiographic follow-up was 100% complete at 4.1 ± 1.8 years. Hospital mortality was 5.6%. Actuarial 5-year survival was 88.5% ± 0.067%. Postoperative echocardiography showed significant regression of left ventricular mass index and significant reductions of peak gradient, mean gradient and mean effective orifice area index. All survivors were interviewed using the 36-item Short Form Health Survey questionnaire. Scores obtained in 7 of the 8 domains of the test were significantly higher than preoperative values. In our experience, implantation of this prosthesis allowed regression of left ventricular mass index and improved the perceived quality of life.

The right choice of prosthesis for patients undergoing aortic valve surgery: searching the truth

Aortic valve surgery is suggested when native aortic valve is diseased and complications outweigh the risks. Choice of prosthesis for aortic valve surgery is vastly undetermined, in part due to the varied options (bioprosthetic, mechanical prosthesis, homografts and allografts) available. The technical issues during valve surgery and the anticoagulation concerns along with the patient type with respect to age, ethnicity, sex and quality of life do contribute to the challenge for deciding the type of valve prosthesis best substituted to the diseased native valve. Here we attempt to unravel the controversies and present a holistic approach towards settling on the best possible prosthesis for a diseased aortic valve.

Early Hemodynamic Results of the Shelhigh SuperStentless Aortic Bioprostheses

BACKGROUND

Stentless valves have been demonstrated excellent hemodynamic performances favoring the recovery of left ventricular function and the ventricular hypertrophy regression. The aim of the study was to evaluate the early hemodynamic performance of the Shelhigh SuperStentless aortic valve (AV).

METHODS

Between July 2003 and June 2005, 35 patients (18 females; age 70.8 +/- 11.7 years, range: 22-85) underwent AV replacement with the Shelhigh SuperStentless bioprostheses. Most recurrent etiology was senile degeneration in 25 (71%) patients and 24 (69%) were in New York Heart Association (NYHA) functional class III or IV. Concomitant coronary artery bypass grafting was performed in nine patients (25.7%) and mitral valve surgery in two patients (5.7%). Doppler echocardiography was performed before surgery, at six-month and one-year follow-up.

RESULTS

There were no hospital deaths and no valve-related perioperative complications. During one-year follow-up, no endocarditis or thromboembolic events were registered, no cases of structural dysfunction or valve thrombosis were noted. Mean and peak transvalvular gradients significantly decrease after AV replacement, with an evident reduction to approximately 50% of the preoperative values at six months. A 20% reduction was also observed for left ventricular mass (LVM) index at six months, with a further regression at one year. Correspondingly, significant increases in effective orifice area (EOA) and indexed EOA were determined after surgery (0.87 +/- 0.14 versus 1.84 +/- 0.29 cm2 and 0.54 +/- 0.19 versus 1.05 +/- 0.20 cm2/m2, respectively). Valve prosthesis-patient mismatch was moderate in five patients and severe in one case.

CONCLUSIONS

Shelhigh SuperStentless AV provided good and encouraging hemodynamic results. Long-term follow-up is necessary to evaluate late hemodynamic performance and durability of this stentless bioprosthesis.

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.

Impact of Left Ventricular Loading Conditions on Myocardial Deformation Parameters: Analysis of Early and Late Changes of Myocardial Deformation Parameters after Aortic Valve Replacement

Myocardial deformation imaging is used to assess regional left ventricular (LV) function. We sought to define the impact of changes in LV loading conditions on myocardial deformation parameters. Aortic valve replacement in patients with different aortic valve pathologies was used as a model to assess the impact of preload and afterload changes. In 53 patients scheduled for aortic valve replacement serial echocardiographic studies were performed preoperatively and postoperatively (within 7 days and at 6 months). Parasternal short-axis views were acquired. Using novel computer software radial and circumferential strain and strain rate were determined as parameters of myocardial deformation for each segment of the LV and were subsequently averaged. Immediately postoperatively there was a relative increase of radial strain by 4.5 +/- 1.8% after valve replacement for aortic stenosis (AS) (P < .001), a relative decrease of 9.4 +/- 7.7% after valve replacement for aortic regurgitation (aortic insufficiency [AI]) (P < .001), and unchanged radial strain after valve replacement for AS and aortic regurgitation. During the subsequent 6 months of follow-up, there was additional relative increase of radial strain by 5.2 +/- 3.1% in the AS group (P < .001), by 12.0 +/- 13.7% in the AI group (P < .01), and by 5.6 +/- 3.4% in the AS and AI group (P < .001). Similar changes were observed for the other strain and strain rate parameters. In conclusion, myocardial deformation parameters change significantly immediately after aortic valve replacement for AS or AI indicating a dependency of determined myocardial deformation parameters on LV preload and afterload.

Sorin stentless pericardial valve versus Carpentier–Edwards Perimount pericardial bioprosthesis: Is it worthwhile to struggle?

We compared two bovine pericardium prostheses (Sorin Freedom versus Carpentier-Edwards Perimount) in patients with small aortic annulus, randomizing 80 patients affected by prevalent aortic stenosis and studying the residual gradient, the effective orifice area, the left ventricular mass regression and the ventricular function to evaluate the cost-benefit in terms of risk-advantages for the patient.

Coronary Insufficiency After Stentless Aortic Root Replacement: Risk Factors and Solutions

BACKGROUND

Coronary insufficiency is a dreaded complication of total aortic root replacement (ARR) with few defined risk factors. This study describes the incidence, risk factors, management options, and outcomes of this condition after ARR with stentless porcine valves.

METHODS

The study consisted of a retrospective analysis of 503 patients (mean age, 68.9 +/- 10.2 years) undergoing stentless porcine total ARR (Medtronic Freestyle and St. Jude Toronto) between the years 1993 and 2005 at a single institution. Coronary insufficiency was defined as the need for unplanned bypass grafting during, or after removal from cardiopulmonary bypass to correct wall motion abnormalities, arrhythmias, or right ventricular failure in the absence of known obstructive coronary disease.

RESULTS

A total of 13 cases of right coronary artery and no cases of left coronary insufficiency were identified (overall incidence 13 of 503, 2.6%). All were treated with aortocoronary bypass grafting to the right coronary artery using saphenous vein. Compared with patients who did not have coronary insufficiency, patients with this complication were more likely to be female (11 of 13, 85%, versus 201 of 490, 41%; p = 0.006), had higher mean body mass index (34.6 +/- 12.0 kg/m2 versus 28.3 +/- 3.8 kg/m2, p = 0.04), and were implanted with smaller prostheses (23.9 +/- 2.1 mm versus 25.6 +/- 2.4 mm, p = 0.026), a finding not explained by the preponderance of female sex. Mean age, ejection fraction, and other demographic variables were similar. Despite longer cardiopulmonary bypass times (238 +/- 61 minutes versus 180 +/- 35 minutes, p = 0.005), operative mortality was not significantly different (1 of 13, 7.7%, versus 29 of 490, 5.9%; p = not significant).

CONCLUSIONS

Coronary artery insufficiency is uncommon after stentless aortic root replacement and more often affects the right coronary artery. Risk factors appear to be female sex, higher body mass index, and small aortic root. Preventive measures include recognition of coronary orientation, routine valve rotation, and adequate coronary button mobilization. When this complication occurs, good outcomes can still be obtained with early recognition and prompt bypass grafting.

Stentless valves for aortic valve replacement: where do we stand?

PURPOSE OF REVIEW

Following more than a decade's experience with stentless valves and the development of better profiled stented valves, the article discusses the advantages of stentless valves regarding hemodynamic performance, left ventricular mass regression, durability and survival.

RECENT FINDINGS

Recent studies show that stentless valves remain hemodynamically superior compared with modern porcine stented valves. This superiority is, however, rarely reported in comparison with modern pericardial stented valves. In general, patient-prosthesis mismatch is less frequent in stentless vs. stented valves. Recent randomized trials comparing stentless valves and modern stented valves show equivalent left ventricular mass regression at 1 year. At 10 years, stentless valve durability is excellent and comparable with that of stented valves. Recent comparative studies do not confirm the previously reported midterm survival advantages of stentless valves.

SUMMARY

Improvement of stented valves has significantly reduced the hemodynamic differences between them and their stentless counterpart. Patients with small aortic annulus, however, should benefit from a stentless valve due to the better expected gradients and lower risk of patient-prosthesis mismatch. Midterm results suggest equivalent durability and survival for both prosthesis types but additional and longer-term trials are necessary to confirm these results.

Evaluation of Left Ventricular Functions after Aortic Valve Replacement in a Specific Young Male Patient Population with Pure Aortic Insufficiency or Aortic Stenosis: 5-Years Follow-up

BACKGROUND

The aim of this study was to evaluate the left ventricular functions and the regression of left ventricular hypertrophy after aortic valve replacement (AVR) in young male patients with pure aortic stenosis or aortic insufficiency with no additional disease.

METHODS

Young male patients who underwent AVR because of pure aortic stenosis (AS = 68) and insufficiency (AI = 70) were enrolled in the study. The mean age was 23.2 +/- 1.3 and 22.6 +/- 1.6 years, respectively. The follow-up time was 5 years. The parameters checked by transthoracic echocardiography were interventricular septum diastolic thickness, left ventricular posterior wall diastolic thickness, left ventricular end-diastolic diameter, left ventricle mass, left ventricle mass index, ejection fraction, and peak aortic gradient. Relative ventricle wall thickness was also calculated. Both groups values from the preoperative, postoperative sixth month, second year, and fifth year time intervals were compared.

RESULTS

In the AS group, the preoperative left ventricular ejection fraction (%) value of 53.68 +/- 5.04 increased to 63.24 +/- 4.11 at the end of the fifth year. In the AI group, the preoperative left ventricular ejection fraction (%) value of 48.40 +/- 3.56 increased to 59.77 +/- 2.75 at the end of the fifth year. The other left ventricular geometric parameters were also compared within each group. At the end of the fifth year, there were significant and positive changes in each group.

CONCLUSION

The regression of the left ventricular parameters is a process that occurs over many years following the correction of the primary hemodynamic abnormality. Although the results were similar in the AI and AS group, in the AS group the remodeling process had earlier results than in the AI group.

Technique for implant of the stentless aortic valve Freedom Solo

In this presentation we provide a summary of aortic valve replacement with a supra-annular stentless aortic valve, the Freedom Solo prosthesis. Stentless valves were designed to provide more physiological flow and lower transvalvular gradient, which is offered by the novel design of the valve and by its implantation technique. The supra-annular stentless aortic valve implantation is demonstrated with a special emphasis on its surgical technique peculiarities.

The effect of aortic valve replacement on N-terminal natriuretic propeptides in patients with aortic stenosis

BACKGROUND

Increased plasma concentrations of natriuretic peptides have been demonstrated to be associated with increased intracardiac pressure and left ventricular (LV) hypertrophy. After aortic valve replacement (AVR) in aortic stenosis patients, there is a relief of the left outflow obstruction with a substantial hemodynamic improvement. This is followed by a gradual regression of the LV hypertrophy.

HYPOTHESIS

After AVR, reduction in LV filling pressure is expected to occur rapidly, while regression of LV hypertrophy will take place over a longer time period. On this basis we hypothesized that the plasma levels of N-terminal proatrial natriuretic peptide (NT-proANP) would be reduced early in the postoperative period, while N-terminal probrain natriuretic peptide (NT-proBNP), through its closer reflection of LV hypertrophy, would be sustained for a longer period.

METHODS

Two groups of patients with aortic stenosis undergoing AVR were followed for 4 and 12 months, respectively. Plasma concentrations of NT-proANP and NT-proBNP were measured before and after AVR and related to preoperative findings and changes in the aortic valve area index.

RESULTS

Before AVR, the patients had significantly increased plasma levels of NT-proANP and NT-proBNP. After AVR, NT- proANP was decreased at 4 and 12 months but remained elevated compared with controls. N-terminal-proBNP tended to decrease, but did not change significantly. When the patients were followed for 12 months, only those with elevated preoperative pulmonary capillary wedge pressure had decreased peptide levels (NT-proANP: p = 0.017, NT-proBNP: p = 0.058). There was no regression of LV hypertrophy. The patients with the largest postoperative valve area index [1.27 (1.10-1.55) cm2/m2] had the largest reduction of NT-proBNP (47%). Those with the smallest valve area index [0.67 (0.54-0.73) cm2/m2] had no decrease in NT-proBNP.

CONCLUSIONS

Our study suggests that a reduction in left atrial pressure is the main factor causing the change of NT-proANP level after AVR. A small prosthetic valve orifice area with a high aortic valve gradient might prevent regression of LV hypertrophy, thus representing a stimulus for increased cardiac secretion of NT-proBNP.

Results of Aortic Valve Replacement With a New Supra-Annular Pericardial Stented Bioprosthesis

BACKGROUND

The stented Soprano valve (Sorin Biomedica S.pA., Saluggia, Italy) is a pericardial tissue valve designed for a totally supra-annular implant with the aim of improving hemodynamic performance, particularly in patients with a reduced aortic annulus. However, its hemodynamics and early clinical outcome are poorly understood.

METHODS

Seventy-seven patients (mean age 76 +/- 5 years, 56% males) underwent aortic valve replacement with the Soprano valve. All patients were monitored with clinical examination and serial echocardiography at 1, 6, and 12 months and yearly afterward.

RESULTS

At preoperative echocardiography, average left ventricular outflow tract diameter was 2.1 +/- 0.2 cm. At operation, 35% of patients received a 20-mm valve, 54% a 22-mm valve, and 11% a 24-mm valve. At 6-month follow-up, peak and mean transprosthetic gradients were 18 +/- 8 and 9 +/- 4 mm Hg, respectively; effective orifice area (EOA) and EOA index were 1.84 +/- 0.6 cm2 and 0.9 +/- 0.2 cm2/m2, respectively. Incidence of patient-prosthesis mismatch (ie, EOA index < 0.85 cm2/m2) was 23%, with no case of severe mismatch (ie, EOA index < 0.6 cm2/m2). In addition, left ventricular hypertrophy showed a significant regression (mass index from 214 +/- 98 g to 129 +/- 41 g; p = 0.001), and ejection fraction increased (from 58% +/- 17% to 67% +/- 8%; p = 0.001). Cumulative follow-up was 7.9 months per patient. Thirty-day mortality rate was 2.6% (2 of 77). Cumulative survival at 6, 12, and 24 months was 92% +/- 3.7%, 85% +/- 5.7%, and 85% +/- 5.7%, respectively. Two patients experienced embolic episodes. One case of anticoagulant-related bleeding occurred.

CONCLUSIONS

In our series, the Soprano bioprosthesis showed a good hemodynamic performance, low incidence of patient-prosthesis mismatch, and favorable early clinical results.

Root Replacement Using Stentless Valves in the Small Aortic Root: A Propensity Score Analysis

BACKGROUND

Root replacement using a stentless bioprosthesis may be the optimal approach to avoid patient-prosthesis mismatch in patients with a small aortic root. Primary root replacement, however, is considered to be associated with increased surgical risk. We compared early outcome of full root replacement with a stentless bioprosthesis with that of aortic valve replacement with a stented bioprosthesis using propensity score-matching analysis.

METHODS

Of 231 patients undergoing elective, first-time aortic valve replacement with a small root (< or = 22 mm), 120 patients were selected using propensity score-matching analysis. They underwent either root replacement using a 23-mm stentless bioprosthesis (stentless group, n = 60) or supra-annular aortic valve replacement using a 21-mm stented bioprosthesis (stented group, n = 60). Preoperative characteristics and frequency of concomitant operations were identical.

RESULTS

Duration of operation (196 +/- 54 versus 174 +/- 49 minutes), cardiopulmonary bypass (112 +/- 36 versus 91 +/- 33 minutes), and aortic cross-clamping (76 +/- 21 versus 61 +/- 21 minutes) were significantly longer in the stentless group. However, the need for perioperative transfusion and the incidence of postoperative reexploration for bleeding (3% versus 8%) was lower, and ventilation time was shorter. Mean duration of intensive care and hospital stay were also significantly shorter (2.3 +/- 1.7 versus 4.0 +/- 3.9 days, 8.9 +/- 3.1 versus 12.4 +/- 5.7 days). In-hospital mortality was identical (5% each). No independent predictor for in-hospital mortality was identified.

CONCLUSIONS

Full root replacement using a stentless bioprosthesis does not increase postoperative morbidity or mortality of aortic valve replacement and may be advantageous in patients with a small aortic root.

Evaluation of 17-mm St. Jude Medical Regent prosthetic aortic heart valves by rest and dobutamine stress echocardiography

BACKGROUND

The prosthesis used for aortic valve replacement in patients with small aortic root can be too small in relation to body size, thus showing high transvalvular gradients at rest and/or under stress conditions. This study was carried out to evaluate rest and Dobutamine stress echocardiography (DSE) hemodynamic response of 17-mm St. Jude Medical Regent (SJMR-17 mm) in relatively aged patients at mean 24 months follow-up.

METHODS AND RESULTS

The study population consisted of 19 patients (2 men, 17 women, mean age 69.2 +/- 7.3 years). All patients underwent rest Doppler echocardiography before and after surgery and basal and DSE at follow up (infused at rate of 5 microg/Kg/min and increased by 5 microg/Kg/min at 5 min intervals up to 40 microg/Kg/min). The following parameters were evaluated at rest and/or under DSE: heart rate (HR), ejection fraction (EF), cardiac output (CO), peak and mean velocity and pressure gradients (MxV, MnV, MxPG, MnPG), effective orifice area (EOA), indexed EOA (EOAi), left ventricular mass (LVM), indexed LVM (LVMi), Velocity Time Integral at left ventricular outflow tract (VTI LVOT) and transvalvular (Aortic VTI), Doppler velocity index (DVI). At rest MxPG and MnPG were 29.2 +/- 7.1 and 16.6 +/- 5.8 mmHg, respectively; EOA and EOAi resulted 1.14 +/- 0.3 cm(2) and 0.76 +/- 0.2 cm(2)/m(2); DVI was normal (0.50 +/- 0.1). At follow-up LVM and LVMi decreased significantly from pre-operative value of 258 +/- 43 g and 157.4 +/- 27.7 g/m(2) to 191 +/- 23.8 g and 114.5 +/- 10.6 g/m(2), respectively. DSE increased significantly HR, CO, EF, MxGP (up to 83.4 +/- 2 1.9 mmHg), MnPG (up to 43.2 +/- 12.7 mmHg). EOA, EOAi, DVI increased insignificantly (from baseline up to 1.2 +/- 0.4 cm(2), 0.75 +/- 0.3 cm(2)/m(2) and 0.48 +/- 0.1 respectively). Two patients developed significant intraventricular gradients.

CONCLUSION

These data show that SJMR 17-mm prostheses can be safely implanted in aortic position in relatively aged patients, offering a satisfactory hemodynamic performance at rest and under DSE, with full utilization of its available orifice, suggesting that a possible mild prosthesis-patient mismatch is not an issue of clinical relevance when this small prosthesis is used. Rest and Dobutamine stress echocardiography is a useful and effective means for evaluating prosthesis hemodynamics and for monitoring the expected LVH regression.

Are Stentless Valves Superior to Modern Stented Valves?: A Prospective Randomized Trial

BACKGROUND

It is presumed that stentless aortic bioprostheses are hemodynamically superior to stented bioprostheses. A prospective randomized controlled trial was undertaken to compare stentless versus modern stented valves.

METHODS AND RESULTS

Patients with severe aortic valve stenosis (n=161) undergoing aortic valve replacement (AVR) were randomized intraoperatively to receive either the C-E Perimount stented bioprosthesis (n=81) or the Prima Plus stentless bioprosthesis (n =80). We assessed left ventricular mass (LVM) regression with transthoracic echocardiography (TTE) and magnetic resonance imaging (MRI). Transvalvular gradients were measured postoperatively by Doppler echocardiography to compare hemodynamic performance. There was no difference between groups with regard to age, symptom status, need for concomitant coronary artery bypass surgery, or baseline LVM. LVM regressed in both groups but with no significant difference between groups at 1 year. In a subset of 50 patients, MRI was also used to assess LVM regression, and again there was no significant difference between groups at 1 year. Hemodynamic performance of the 2 valves was similar with no difference in mean and peak systolic transvalvular gradients 1 year after surgery. In patients with reduced ventricular function (left ventricular ejection fraction [LVEF] <60%), there was a significantly greater improvement in LVEF from baseline to 1 year in stentless valve recipients.

CONCLUSIONS

Both stented and stentless bioprostheses are associated with excellent clinical and hemodynamic outcomes 1 year after AVR. Comparable hemodynamics and LVM regression can be achieved using a second-generation stented pericardial bioprosthesis. In patients with ventricular impairment, stentless bioprostheses may allow for greater improvement in left ventricular function postoperatively.

Clinical and hemodynamic implications of supra-annular implant of biological aortic valves

The use of stented bioprostheses in elderly patients with degenerative aortic stenosis, despite being desirable, raises concerns about the harmful effects of residual obstruction to left ventricular outflow. To overcome this limitation new stented and stentless bioprostheses have been designed for supra-annular implant. However, the actual hemodynamic advantage of supra-annular implant over the intra-annular one remains incompletely understood. This review focuses on the geometry of biological valve prostheses designed for supra-annular implant and its implications for the echocardiographic assessment of valve hemodynamics. Available data about the hemodynamic performance of these valves implanted in the supra-annular position in comparison with the usual intra-annular implant are also reviewed. Other issues related to biological heart valve performance, such as biomaterials, tissue mechanics, durability, and clinical outcome are not addressed in this review.

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.