Left ventricular mass reduction after aortic valve replacement: homografts, stentless and stented valves

Structural abnormalities after aortic root replacement with stentless xenograft

OBJECTIVE

In complex and high-risk aortic root disease, the porcine Freestyle stentless bioprosthesis (Medtronic Inc, Minneapolis, Minn) is an important surgical treatment option. We aimed to determine prevalence and clinical effect of structural and functional abnormalities after full-root Freestyle implantation.

METHODS

Our cross-sectional 2-center study combined with clinical follow-up included 253 patients with full-root Freestyle bioprostheses implanted from 1999 to 2017. Patients underwent transthoracic echocardiography (TTE) and contrast-enhanced, electrocardiogram-gated 4-dimensional cardiac computed tomography (4DCT) at median age 70 (interquartile range, 62-75) years. After 4DCT, clinical follow-up continued throughout 2018. Median follow-up was 3.3 years before 4DCT and 1.4 years after.

RESULTS

We identified abnormalities in 46% of patients, including pseudoaneurysms (n = 32; 13%), moderate or severe coronary ostial stenosis (n = 54; 21%), and moderate-severe leaflet thickening or reduced leaflet motion (n = 51; 20%). TTE only identified 1 patient with pseudoaneurysm. After 4DCT, the unadjusted hazard ratio for surgical reintervention among patients with abnormal 4DCT was 4.2 (95% confidence interval, 1.2-15.3), in all, 10% required a reintervention. 4DCT abnormalities were associated with a statistically nonsignificant increased risk of death, stroke, or myocardial infarction (hazard ratio obtained using Cox proportional hazards regression analysis, 2.4; 95% confidence interval, 0.7-7.6). In all, 4.0% died, 3.6% had a myocardial infarction, and 2.0% had a stroke.

CONCLUSIONS

Structural and functional abnormalities of the aortic root are frequent after Freestyle implantation and TTE appears to be insufficient for follow-up. Abnormalities might be associated with increased risk of reintervention and potentially adverse clinical outcomes. Longer follow-up and larger study populations are needed to further clarify the clinical implications of abnormalities identified with 4DCT.

Structural valve deterioration and mode of failure of stentless bioprosthetic valves

BACKGROUND

Aortic stentless bioprosthetic valve (SLBPV), either porcine or pericardial, minimizes transvalvular gradient and favors regression of left ventricular hypertrophy. The drawback consists of longer time for suturing. While structural valve deterioration (SVD) in stented porcine and pericardial BPVs has been extensively investigated, less information is available on SLBPVs.

MATERIAL AND METHODS

We studied 82 SLBPVs explants, either porcine (Toronto SPV, [St. Jude Medical, MN, USA], CryolifeO'Brien Model 300 and CryoLife-O'Brien [Cryolife International, GA, USA], BioCor PVS [St. Jude Medical, MN, USA] Prima and Prima Plus [Edwards Lifesciences Corp. One Edwards Way, CA, formerly Baxter Inc, CA, USA]) or pericardial ([Pericarbon Freedom and Freedom Solo [Sorin-Biomedica, S.p.A., Saluggia, Italy]).

RESULTS

By excluding cases with leak and endocarditis, we focused the investigation on 46 SLBPVs, which failed because of SVD. Gender was male in 29 (63%). Mean age of patients at time of implant was 59.8 years. Postoperative time of SVD was 115.0 months for porcine and 79.0 months for pericardial SLBPVs. Dysfunction requiring reoperation was mainly incompetence for porcine and stenosis for pericardial SLBPVs. Even pinpoint mineralization at the commissures resulted in sudden cusp tearing and incompetence. Cuspal atheromasia accounted for cusp tearing even in the absence of calcification. Mineralization showed progression with time in pericardial but not in porcine SLBPVs.

CONCLUSIONS

Tissue mineralization remains the nightmare also of SLBPVs, with the peculiar features of pinpoint calcific deposits at commissures, tearing and abrupt incompetence in porcine SLBPVs and of massive cuspal mineralization and stenosis in pericardial SLBPVs.

Midterm outcomes of subcoronary stentless porcine valve versus stented aortic valve replacement

INTRODUCTION

Stentless porcine xenografts are versatile bioprosthetic valves with the advantage of improved hemodynamics that mimic the function of the native aortic valve. However, these bioprostheses are challenging to implant in the subcoronary position.

METHODS

All consecutive patients who underwent a bioprosthetic aortic valve replacement (AVR) were included from our institutional database. Cox regression analysis was preformed to determine significant predictors for mid term mortality as well as all cause, cardiac, and heart failure readmission.

RESULTS

Patients in the subcoronary stentless group were older and more likely to be female and were likely to have a higher Society of Thoracic Surgery risk of mortality. Survival was superior in the stented AVR cohort at 30-days (96.4% vs 90.5%; P < .001), 1-year (90.5% vs 71.6%; P < .001), and 5-year (74.5% vs 56.9%; P < .001) follow up. Acute kidney injury (16.22% vs 5.22%; P < .001) and blood product transfusion (70.27% vs 44.0%; P < .001) were higher in the stentless group. Multivariable analysis revealed subcoronary stentless implantation as a significant independent risk factor for mortality (hazards ratio: 1.92 [1.35,2.72]; P < .001).

CONCLUSION

Stentless porcine xenograft implantation with the Freestyle bioprosthetic in the subcoronary position can be successfully performed in select patients, but its use is associated with increased perioperative morbidity and mortality affecting midterm outcomes. Individual patient selection and surgeon experience are important to ensure favorable outcomes.

TAVI-in-homograft (TiH): open transcatheter aortic valve replacement in calcified aortic homograft case reports

Background

Redo surgery in patient who underwent aortic valve replacement with an aortic homograft can result technically challenging because of the massive calcification of the conduit.

Case presentation

We present a case of a patient who underwent open surgery on cardiopulmonary bypass assistance to implant a standard transcatheter aortic bioprosthesis through aortotomy in an off-label procedure and we discuss its safety and feasibility.

Conclusions

The combination of open cardiac surgery and open trans-aortic implant of a transcatheter prosthesis may reduce the surgical risk shrinking the technical difficulties that the implantation of a standard surgical prosthesis would have given.

Stented versus Stentless Aortic Valve Replacement in Patients with Small Aortic Root

Objective

The aim of the study was to compare hemodynamic and perioperative outcomes of stented against stentless aortic valve replacement in patients with small aortic root (21 mm or less).

Methods

A comprehensive search was undertaken among the four major databases (PubMed, Embase, Scopus, and Ovid) to identify all randomized and nonrandomized controlled trials comparing stentless to stented bioprosthetic valves in small aortic root patients. Odds ratios, weighted mean differences, or standardized mean differences and their 95% confidence intervals were analyzed.

Results

A total of seven studies with a total of 965 patients fulfilled the inclusion criteria. There was no significant difference in preoperative baselines including mean age between both groups ( P = 0.08), peak aortic valve gradient ( P = 0.06), and effective orifice area ( P = 0.28), whereas higher mean aortic valve gradient in the stented group ( P = 0.007). No difference in cardiopulmonary bypass time ( P = 0.74), aortic cross-clamp times ( P = 0.88), intensive care unit stay ( P = 0.13), and stroke rate ( P = 0.56) were noted. However, stented group of patients showed higher rate of patient prosthesis mismatch ( P = 0.0001) and longer total hospital stay ( P = 0.002). Postoperatively, stentless group showed lower peak and mean aortic valve gradient ( P = 0.003 and P = 0.008, respectively) with a better effective orifice area ( P < 0.00001) at 6 months of follow-up. Mortality rates while in-hospital and at 1 year were similar in both groups ( P = 0.94 and P = 0.86, respectively).

Conclusions

Stentless aortic valves offer superior short-term hemodynamic outcomes in patients with small aortic root when compared with stented aortic valves. Although both groups have similar perioperative complications rates, stentless valves bring about a shorter hospital stay. A further large multicenter randomized controlled trial should address the longer-term benefit of stentless aortic valve over stented valve.

Different Types of Aortic Stenosis and Simulation of their Morphological-Hydrodynamic Interdependence - in Vitro Study with Allografts and Stenotic Valve Models

Biological valves display a dependence of valve resistance and valve area on flow and a phase shift between systolic flow through the valves and pressure difference across the valves. The pressure-flow relations of stenosed valves raise questions about the “best measure of stenosis”. There is a need for quantitative evaluation of the hydrodynamic performance of homografts and allografts. In the present paper, we report on in vitro studies of the hydrodynamic behavior of homografts from human donors, allografts from different animal species as well as three valve models. Valve model I was designed to simulate flow-dependence of valve area, valve model II was designed to simulate restricted valve opening independent of flow, and valve model III was designed to simulate a flow-dependent movement of valve root in flow direction. Among other aspects, the effect of increased viscosity of the test fluid on the pressure difference and the effects of water absorption by valve tissue on valve characteristics were investigated. The results of the present studies clearly indicate that any biological valve may be modelled as a serial connection of a model I type valve and a model II type valve. From the results, the dependence of the characteristic pressure-flow relationship of a valve on valve size and valve distensibility can be clearly seen and the clinical significance of the characteristic coefficients of the pressure-flow relationship of a valve can be elucidated. Further, it was shown that the characteristic phase shift between flow and pressure difference displayed by biological valves is due to their movable valve plane similar to that of valve model III.

The freestyle aortic bioprosthesis: a systematic review

BACKGROUND

The Medtronic Freestyle bioprosthesis (FSB) provides an alternative to other prostheses for both aortic valve and aortic root surgery. This paper is a systematic review of the post-operative outcomes in patients with aortic valve and/or aortic root disease following FSB implantation.

METHODS

Electronic databases were searched for primary analysis, prospective randomised studies comparing the FSB with an alternative aortic prosthesis were included. Additionally, case series that included data for at least 100 individual operated patients were used for secondary analysis.

RESULTS

Among three identified randomised studies, 199 FSB cases were compared with homografts, and stented and an alternative stentless bioprosthesis. The FSB showed comparable hospital mortality (4.5% vs. 5.3%) and eight-year actuarial survival (80±5.0% versus 77±6.0%) with the homograft (respectively) and comparable reduction in left ventricular mass index relative to other prosthesis types. Over 6000 individual patients were included in the selected 15 case series. Weighted mean operative mortality, neurological event rate and five-year actuarial survival was 5.2%, 5.5% and 77.8%, respectively.

CONCLUSION

The FSB performed comparably against alternative prostheses regarding in-hospital mortality, long-term survival and reduction in left ventricular mass index. Included case series demonstrated robust post-operative outcomes in both the short and long term.

Homografts: a review

Since their introduction into clinical practice in 1965 homografts have become established in clinical routine. The storing and sterilization procedures have been improved over time. Long-term results showed that homografts had a superior durability compared to xenogenic biological prostheses. Approximately 40% were still in place 20 years after implantation in aortic position. Their low rate of thromboembolic events made a life-time anticoagulative therapy unnecessary and their hemodynamics were superior to all other heart valve prostheses. There exist two implantation techniques, subcoronary or mini-root, both technically more demanding compared with implantation of stented valve prostheses. When using the subcoronary technique, the valve is suspended into the aortic root leaving the coronary arteries untouched. The success of this technique, however, depends on the relation of the recipients aortic root and the implanted valve. The mini-root technique requires reimplantation of the coronary arteries but left the morphology of the valve and its root unchanged. Especially in patients with endocarditis, the mini-root technique offered the advantage of allowing for excision of all affected tissue with subsequent replacement by the homograft. The Ross-procedure uses the patient's own pulmonary valve as aortic valve substitute with implantation of a homograft in pulmonary position. This proved to be advantageous in children, since in these patients the degeneration of an aortic homograft was faster compared to an older population. This was explained by the recipient's immunologic response to the graft which was more pronounced in younger patients. The advantages of homografts with regards to hemodynamics and thromboembolic risk make them a good alternative to mechanical prostheses in younger, active patients. In very young patients, a Ross-procedure was shown to be superior to aortic homografts due to slower degeneration of the autograft. The decision to use a homograft must be made individually according to the patients demands.

Stentless aortic valve replacement: current status and future trends

Stentless aortic xenografts were introduced into clinical practice as aortic valve substitutes over a decade ago. Stentless prosthetic valves were expected to provide enhanced durability and more physiologic hemodynamic behavior when compared with stented bioprostheses. Whilst the former expectation has not been fulfilled, partly due to concomitantly improved durability of second-generation stented bioprostheses, the latter has consistently been satisfied in early and late clinical observation. Evidence is accumulating suggesting improved long-term survival due to more timely and thorough regression of ventricular hypertrophy. In addition, stentless xenografts have shown extreme versatility when adopted in a variety of complex clinical conditions associated with aortic valve disease, including small aortic anulus, ascending aortic aneurysm, endocarditis and left ventricular dysfunction. Future research in the form of prospective, multicenter, randomized trials must address the issues of very long-term durability and survival, while simplification in valve design is required to promote wider use of stentless valves.

Longitudinal strain predicts left ventricular mass regression after aortic valve replacement for severe aortic stenosis and preserved left ventricular function

We explored the influence of global longitudinal strain (GLS) measured with two-dimensional speckle-tracking echocardiography on left ventricular mass regression (LVMR) in patients with pure aortic stenosis (AS) and normal left ventricular function undergoing aortic valve replacement (AVR). The study population included 83 patients with severe AS (aortic valve area <1 cm(2)) treated with AVR. Bioprostheses were implanted in 58 patients (69.8 %), and the 25 remaining patients (30.2 %) received mechanical prostheses. Peak systolic longitudinal strain was measured in four-chamber (PLS4ch), two-chamber (PLS2ch), and three-chamber (PLS3ch) views, and global longitudinal strain was obtained by averaging the peak systolic values of the 18 segments. Median follow-up was 66.6 months (interquartile range 49.7-86.3 months). At follow-up, values of PLS4ch, PLS2ch, PLS3ch, and GLS were significantly lower (less negative) in patients who did not show left ventricular (LV) mass regression (all P < 0.001). Baseline global strain was the strongest predictor of lack of LVMR (odds ratio 3.5 (95 % confidence interval 3.0-4.9), P < 0.001), and GLS value ≥-9.9 % predicted lack of LVMR with 95 % sensitivity and 87 % specificity (P < 0.001). Other multivariable predictors were the preoperative LV mass value (cutoff value ≥147 g/m(2), P < 0.001), baseline effective orifice area index (cutoff ≤0.35 cm(2)/m(2), P = 0.01), and baseline mean gradient (cutoff ≥58 mmHg, P = 0.01). Finally, we failed to find interactions between GLS and other significant parameters (all P < 0.05). Global longitudinal strain accurately predicts LV mass regression in patients with pure AS undergoing AVR. Our findings must be confirmed by further larger studies.

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.

Midterm results of aortic valve replacement with cryopreserved homografts

OBJECTIVE

The aim of this study was to analyze the midterm clinical results of aortic valve replacement with cryopreserved homografts.

MATERIALS AND METHODS

Aortic valve replacement was performed in 40 patients with cryopreserved homograft. The indications were aortic valve endocarditis in 20 patients (50%), truncus arteriosus in 6 patients (15%), and re-stenosis or regurtitation after aortic valve reconstruction in 14 (35%) patients. The valve sizes ranged from 10 to 27mm. A full root replacement technique was used for homograft replacement in all patients.

RESULTS

The 30-day postoperative mortality rate was 12.5% (5 patients). There were four late deaths. Only one of them was related to cardiac events. Overall mortality was 22.5%. Thirty-three patients were followed up for 67±26 months. Two patients needed reoperation due to aortic aneurysm caused by endocarditis. The mean transvalvular gradient significantly decreased after valve replacement (p<0.003). The last follow up showed that the 27 (82%) patients had a normal left ventricular function.

CONCLUSION

Cryopreserved homografts are safe alternatives to mechanical valves that can be used when there are proper indications. Although it has a high perioperative mortality rate, cryopreserved homograft implantation is an alternative for valve replacement, particularly in younger patients and for complex surgical problems such as endocarditis that must be minimalized.

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.

Hemodynamics and Outcomes of Aortic Valve Replacement with a 17- or 19-mm Valve

When aortic valve replacement is performed in patients with a small aortic annulus, prosthesis-patient mismatch is of concern because it may affect postoperative clinical status. We conducted a retrospective study of outcomes in 65 patients with aortic stenosis requiring valve replacement. Fifty were given a 17-mm or 19-mm St. Jude Regent mechanical valve, and 15 were given a 19-mm Medtronic Mosaic bioprosthesis. Echocardiography was carried out preoperatively, at discharge, and at follow-up. There was 1 (2%) operative death in the Regent group and none in the Mosaic group. There was no valve-related event. Follow-up echocardiography in both groups revealed a significant increase in the mean effective orifice area index, a decrease in the mean left ventricular-aortic pressure gradient, and a decrease in the mean left ventricular mass index. Prosthesis-patient mismatch (effective orifice area index <0.85 cm2 · m−2) existed in 13 (26%) patients in the Regent group and 11 (73%) in the Mosaic group at discharge. All patients improved to New York Heart Association functional class II or better. A small-sized prosthesis may provide satisfactory clinical and hemodynamic results in patients with a small aortic annulus.

Does stentless aortic valve implantation increase perioperative risk? A critical appraisal of the literature and risk of bias analysis

Stentless aortic valve replacement has potential benefits in terms of valve hemodynamics and clinical outcomes, although these may be offset by greater technical complexity of implantation with longer cardiopulmonary bypass and cross-clamp times compared with stented valves. Meta-analyses of the small number of published randomized trials have been limited by their lack of critical synthesis of the literature, including evaluation of the Risk of Bias. Our objective was to determine whether stentless aortic valves increase perioperative risk of mortality. We also examined secondary clinical outcomes of neurological, renal and respiratory complications as well as hemodynamic changes reported by studies following implantation of the two types of aortic prosthesis. The methodology used to answer this question was a rigorous meta-analysis of randomized controlled trials, using bias-assessment techniques designed to address limitations of conventional meta-analysis. Our findings show that many of the existing randomized trials have a high or uncertain risk of bias. Analysis of studies with low risk of bias reveals that stentless valves do not increase perioperative risk in terms of 30-day mortality and morbidity though neither do they exhibit benefits in hemodynamics or clinical outcomes compared with stented valves. Larger, more stringent randomized studies would be required to identify any robust clinical difference.

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.

The 17-mm St. Jude Medical Regent valve is a valid option for patients with a small aortic annulus

BACKGROUND

When aortic valve replacement is performed in patients with a small aortic annulus, prosthesis-patient mismatch is of concern. Such prosthesis-patient mismatch may affect postoperative clinical status and survival. We investigated the outcomes of isolated aortic valve replacement performed with a 17-mm mechanical prosthesis in patients with aortic stenosis.

METHODS

Twenty-three patients with aortic stenosis (mean age, 74.6 +/- 6.3 years) underwent isolated aortic valve replacement with a 17-mm St. Jude Medical Regent prosthesis. Mean body surface area was 1.41 +/- 0.13 m(2). Preoperative echocardiography yielded a mean aortic valve area of 0.36 +/- 0.10 cm(2)/m(2), a mean left ventricular-aortic pressure gradient of 68.4 +/- 25.3 mm Hg, and a mean left ventricular mass index of 200 +/- 69 g/m(2).

RESULTS

There was no operative mortality, and there were no valve-related events. Echocardiography at 14.0 +/- 10.0 months after aortic valve replacement showed a significant increase in the mean effective orifice area index (0.95 +/- 0.24 cm(2)/m(2)), decrease in the mean left ventricular-aortic pressure gradient (17.4 +/- 8.2 mm Hg), and decrease in the mean left ventricular mass index (124 +/- 37 cm(2)/m(2)). Prosthesis-patient mismatch (effective orifice area index < 0.85 cm(2)/m(2)) was present in 8 patients at discharge. In these patients as well as in those without prosthesis-patient mismatch, the left ventricular mass index decreased remarkably during follow-up.

CONCLUSIONS

Aortic valve replacement with a 17-mm Regent prosthesis appears to provide satisfactory clinical and hemodynamic results in patients with a small aortic annulus. Remarkable left ventricular mass regression during follow-up was achieved irrespective of the effective orifice area index at discharge.

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.

Longitudinal study of the profile and predictors of left ventricular mass regression after stentless aortic valve replacement

BACKGROUND

The aim of this study was to evaluate the long-term profile and determine the factors that would influence the effect and rate of ventricular mass regression with time after aortic valve replacement with a stentless or a homograft valve.

METHODS

We studied 300 patients during a 10-year period with at least a year of follow-up with a total of 1,273 serial echocardiographic measurements. Left ventricular mass was calculated from M-mode recordings and indexed to body surface area. Longitudinal data analysis was performed using a linear mixed effects model.

RESULTS

The mean age (+/- standard deviation) was 65 (+/-14) years, consisting of 216 (72%) males. A stentless valve was implanted in 156 (52%), and a homograft in 144 (48%). The median time (interquartile range) to follow-up was 4.7 (2.8 to 6.6) years. The greatest rate of left ventricular mass regression occurred in the first year after surgery. On multivariable modeling, independent predictors of left ventricular mass were valve size (p = 0.011), left ventricular function (moderate impairment, p = 0.418; severe impairment, p = 0.011), and baseline left ventricular mass (middle tercile, p < 0.001; highest tercile, p < 0.001). Only baseline ventricular mass influenced the rate of subsequent left ventricular mass regression; the greatest rate of regression occurred in patients with the highest baseline values of ventricular mass (p < 0.001).

CONCLUSIONS

The greatest rate of left ventricular mass regression occurs in the first year with baseline left ventricular mass as the strongest predictor and the only identified variable that influenced the rate of left ventricular mass regression.

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.

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.

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.

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.

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.

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.

The subcoronary Toronto stentless versus supra-annular Perimount stented replacement aortic valve: Early clinical and hemodynamic results of a randomized comparison in 160 patients

BACKGROUND

A stentless valve is expected to be hemodynamically superior to a stented valve. The aim of this study was to compare early postoperative hemodynamic function and clinical events in a randomized, prospective series of 160 stentless and stented biological replacement aortic valves.

METHODS

We randomized 160 consecutive patients on 1 surgeon's list to receive either a Toronto stentless porcine valve (St Jude Medical, Inc, St Paul, Minn) or a Perimount stented bovine pericardial valve (Edwards Lifesciences, Irvine, Calif). Echocardiography was performed at discharge, between 3 and 6 months, and at 1 year after surgery. Statistical analysis was performed by both intention to treat and actual valves implanted.

RESULTS

The mean labeled size of both designs of valve was 24.7. There were no statistically significant differences in results at any time interval or whether analysis was performed by actual valves implanted or intention to treat. At 3 to 6 months for the Toronto versus the Perimount valve, the effective orifice area was 1.58 versus 1.66 cm2, the mean pressure difference was 7.54 versus 7.42 mm Hg, and the peak velocity was 2.07 versus 2.0.1 m/s. There was no difference in mortality, regression of left ventricular hypertrophy, or complications other than paraprosthetic regurgitation at 12 months or on follow-up for a proportion of the sample to 8 years. The incidence of regurgitation through the valves was similar for Toronto (10%) and Perimount (13.8%) at 1 year, but mild paraprosthetic regurgitation was found in 5 patients with the Perimount valve and none with Toronto valves.

CONCLUSIONS

There were no significant differences in hemodynamic function or clinical events between the stented and stentless biological valves chosen for comparison in the early postoperative period or in preliminary follow-up to 5 years.

Aortic Valve Replacement for Aortic Insufficiency: Valve Type as a Determinant of Systolic Strain Recovery

BACKGROUND AND AIM

Left ventricular (LV) 3D systolic strain decreases in absolute value postoperatively and does not recover in patients who undergo aortic valve replacement (AVR) for chronic aortic insufficiency (AI). We investigated whether choice of valve prosthesis (mechanical [St. Jude], bioprosthetic [bovine pericardial], Ross procedure) had a significant impact on strain recovery in this surgical population.

METHODS

MRI with tissue-tagging was performed on 14 patients with chronic AI both before and 28 +/- 13 months after AVR. Average values of LV systolic strain and end-systolic stress (ESS) were computed from MRI data for the LV. Three types of prosthetic valve were examined (Ross procedure n = 4, bovine pericardial n = 5, and St. Jude n = 5).

RESULTS

Overall, systolic strain, ESS, LV volumes, ejection fraction, and LV mass all changed significantly following AVR. Comparisons between individual valve types revealed no differences in any of these measurements. Patients who received a mechanical valve had a greater decrease in the absolute value of systolic strain following surgery compared to patients from the nonmechanical group (Ross procedure and bioprosthetic valve). Comparisons between the Ross group and the prosthetic group (St. Jude and bioprosthetic) produced no significant differences in strain, ESS, LV volume, and mass.

CONCLUSIONS

These early results suggest that valve prosthetic type may be a factor in efforts to improve strain recovery after AVR for AI, although further investigation is warranted. MRI with tissue-tagging may be a useful tool for comparing the impact of prosthetic valve choice on incompletely recovered systolic strain following AVR for chronic AI.

Randomized Comparison of Stentless Versus Stented Valves for Aortic Stenosis

BACKGROUND

Aortic valve replacement (AVR) is the established treatment for severe aortic stenosis. In response to the long-term results of aortic homografts, stentless porcine valves were introduced as an alternative low-resistance valve. We conducted a randomized trial comparing a stentless with a stented porcine valve in adults with severe aortic stenosis.

METHODS AND RESULTS

The primary outcome was change in left ventricular mass index (LVMI) measured by transthoracic echocardiography and, in a subset, by cardiovascular MR. Measurements were taken before valve replacement and at 6 and 12 months. Patients undergoing AVR with an aortic annulus < or =25 mm in diameter were randomly allocated to a stentless (n=93) or a stented supra-annular (n=97) valve. There were no significant differences in mean LVMI between the stentless versus stented groups at baseline (176+/-62 and 182+/-63 g/m2, respectively) or at 6 months (142+/-49 and 131+/-45 g/m2, respectively), although within-group changes from baseline to 6 months were highly significant. Changes in LVMI measured by cardiovascular MR (n=38) were consistent with the echo findings. There was a greater reduction in peak aortic velocity (P<0.001) and a greater increase in indexed effective orifice area (P<0.001) in the stentless group than in the stented group. There were no differences in clinical outcomes between the 2 valve groups.

CONCLUSIONS

Despite significant differences in indexed effective orifice area and peak flow velocity in favor of the stentless valve, there were similar reductions in left ventricular mass at 6 months with both stented and stentless valves, which persisted at 12 months.

Determinants of Incomplete Left Ventricular Mass Regression Following Aortic Valve Replacement for Aortic Stenosis

OBJECTIVE

Incomplete regression of left ventricular hypertrophy (Abn-LVMI) following AVR for aortic stenosis (AS) may decrease long-term survival. In this prospective study, we identified the predictors of Abn-LVMI.

METHODS

Between 1990 and 2000, 529 patients undergoing AVR for AS had clinical and hemodynamic data collected prospectively. Preoperative and annual postoperative transthoracic echos were employed to assess left ventricular mass index (LVMI) and hemodynamics. Abn-LVMI was defined as the 75th percentile of the lowest postoperative LVMI (>128 mg/m2, n = 133). All other patients were included in the normal regression group (N-LVMI). Univariate and multivariable logistic regression analyses were used to determine the predictors of Abn-LVMI.

RESULTS

Preoperative hypertension, diabetes, coronary disease, valve size, mean postoperative gradients, effective orifice area, and patient-prosthesis mismatch (PPM, indexed EOA <0.60 cm2/m2) did not predict Abn-LVMI. By logistic regression the most important positive predictor of Abn-LVMI was the extent of preoperative LVMI, with an odds ratio of 37.5 (p < 0.0001). Survival (93.4 +/- 1.8% vs 94.8 +/- 2.3%, p = 0.90) and freedom from NYHA III-IV (75.0 +/- 3.7% vs 76.6 +/- 5.3%, p = 0.60) were similar for both groups at 7 years.

CONCLUSIONS

Measures of valve hemodynamics were not important predictors of incomplete regression of hypertrophy. The extent of preoperative hypertrophy was the most important predictor, suggesting that earlier surgical intervention may reduce the extent of hypertrophy postoperatively. Furthermore, the significance of LV hypertrophy to long-term survival must be reassessed, in the absence of scientific evidence.

Comparison of changes in diastolic functions after aortic valve replacement with freestyle stentless porcine xenografts in patients with restrictive and nonrestrictive physiology

In this study, the effect of valve replacement on diastolic parameters was evaluated preoperatively and postoperatively at 3, 6, and 12 months by comparing diastolic parameters in patients after aortic valve replacement with freestyle stentless porcine xenografts for aortic stenosis. Depending on deceleration time (DT) and isovolumetric relaxation time (IVRT) with preoperative echocardiographic assessment, patients were divided into two groups: restrictive physiology (DT < or = 150 msec and IVRT < 100 msec, 20 patients), and nonrestrictive physiology (DT > 150 msec and IVRT > or = 100 msec, 27 patients). Although left ventricular mass index significantly decreased in both groups, improvement in DT, IVRT, and ejection fraction occurred only in patients with restrictive physiology. As a result, the patients with restrictive diastolic characteristics had more benefit than the patients with nonrestrictive physiology after aortic valve replacement.

Does the type of prosthesis influence early left ventricular mass regression after aortic valve replacement? Assessment with magnetic resonance imaging

BACKGROUND

Debate exists regarding selection of the prosthesis type most likely to maximize early left ventricular (LV) mass regression after aortic valve replacement (AVR) for stenotic valvular disease. The aim of this study was to compare the degree of LV mass regression measured by MRI 6 months after prospectively randomized valve implantation for two biological prostheses, stented and stentless, and for two mechanical valves, tilting disc and bileaflet.

METHODS

Thirty-nine consecutive patients with predominant aortic stenosis accepted for elective AVR were studied. Twenty patients requiring a tissue prosthesis were randomly assigned to receive either a Freestyle or Mosaic valve. The remaining 19 patients in whom mechanical prosthesis was indicated were randomly assigned to receive either an Ultracor or an ATS valve.

RESULTS

There was no difference in valve size implanted between the compared groups. LV mass measurements were performed with MRI (1.5-T Vision, Siemens, Germany) immediately before and 6 months after surgery. All valve types produced significant postoperative reduction in LV mass compared with preoperative values (P <.01). Percent change in LV mass regression was similar between the two porcine valve types, Mosaic (24.4% +/- 11.1%) and Freestyle (21.1% +/- 16.7%), and between the two mechanical valve designs, Ultracor (19.3% +/- 9.5%) and ATS (26.3% +/- 10.8%), respectively.

CONCLUSIONS

Significant LV remodeling occurs early after AVR for aortic stenosis. The degree of regression in LV mass is independent of prosthesis type implanted.

Comparison of autograft and allograft aortic valve replacement in children

OBJECTIVE

This study was undertaken to compare the clinical and hemodynamic results following aortic valve replacement with a pulmonary valve autograft (Ross procedure) or an allograft valve in children.

METHODS

The records of 107 pediatric aortic valve replacements from 1994 through 2001 were reviewed, including 78 autografts and 25 allografts. Four mechanical aortic valve replacements performed during this period were excluded from analysis.

RESULTS

There were 3 perioperative deaths and 1 late death. Reoperations were required in 5 autograft recipients (with autograft preservation in 4) and in 3 allograft recipients (all requiring valve re-replacement). Seven-year survival (96% in both groups) and reoperation-free survival (88% in the autograft group; 73% in the allograft group, P =.5) were not significantly different. Serial echocardiographic studies showed that in the autograft group, left ventricular outflow tract maximal velocity (2.0-1.8 m/s, P =.02) and left ventricular thickness (10.1-8.4 mm, P <.0001) fell significantly. In the allograft group, maximal velocity (2.3-3.0 m/s, P =.03) increased significantly and left ventricular thickness (9.5-9.0 mm, P =.2) showed minimal change. Analysis according to preoperative physiology (aortic stenosis versus insufficiency), congenital cardiac anatomy, number or type of previous operations, age of patient, and use of balloon valvotomy did not predict outcomes.

CONCLUSIONS

Aortic valve replacement with either the autograft or allograft provides excellent clinical results in children during an intermediate duration of observation. The Ross procedure achieves a superior hemodynamic result, which may be clinically important with longer follow-up.

Regression of left ventricular mass one year after aortic valve replacement for pure severe aortic stenosis

The aim of the study was to quantify a 1-year change in left ventricular (LV) mass index (MI) and systolic LV function in 30 patients with pure severe aortic stenosis by means of serial 3-dimensional (3-D) echocardiography. To assess the completeness of LVMI regression after 1 year, we compared the postoperative mass of patients with mass values of 30 normotensive control subjects without a history of cardiac disease. Ejection fraction increased from 64 +/- 14% before surgery to 69 +/- 8% at follow-up (p = 0.067), and functional class improved from 2.9 +/- 0.5 to 1.4 +/- 0.5 (p <0.05), with improvement in each patient. During the same period, LVMI regressed by 23.4% (p <0.001). Postoperative LVMI was related to preoperative LVMI (r = 0.82; p <0.001) and baseline ejection fraction (r = -0.5; p = 0.009). LVMI regressed into the normal range in 64% of patients at follow-up. Patients achieving normal mass values did not differ with respect to patient gender, valve type, or valve size. Patients with reduced preoperative LV function had larger volumes (p <0.01), larger mass values (p <0.01), and a trend toward more mass regression (p = 0.062) than patients with normal preoperative function. Although ejection fraction improved after 1 year in all of these patients (p <0.03), they were less likely to achieve normal mass values at follow-up (p = 0.01). Regression of LVMI in patients with pure aortic stenosis is a positive event that occurs in each patient and that is associated with improvement in functional status. LVMI regressed into the normal range in most patients with normal preoperative function. Preoperative LV function, but not patient gender, valve type, or size, was related to normalization of LVMI at follow-up in this selected study population.

Surgical management of heart failure

Surgical therapy for congestive heart failure can offer gratifying results in selected elderly patients. Several trials have shown a survival advantage for surgical revascularization compared with medical therapy in the treatment of ischemic cardiomyopathy. Aortic valve replacement is highly effective in treating elderly patients with heart failure caused by severe aortic stenosis, and stentless aortic valves seem to provide a survival advantage in elderly patients with low-gradient aortic stenosis. Mitral valve repair with or without coronary revascularization has been used successfully in patients with severe mitral regurgitation. Transplantation is a viable but rarely used option for elderly patients with congestive heart failure. Totally implantable ventricular assist devices are an exciting new option for elderly patients with congestive heart failure who are not heart transplantation candidates.