Influence of prosthesis size on change in left ventricular mass following aortic valve replacement

Prognostic impact of left ventricular mass regression after transcatheter aortic valve replacement in patients with left ventricular hypertrophy

BACKGROUND

Paravalvular regurgitation (PVR) has been known to be the primary determinant of poor left ventricular (LV) mass regression after transcatheter aortic valve replacement (TAVR). However, the incidence of significant PVR has been reduced considerably as TAVR technology evolved rapidly. This study aimed to investigate the time course and impact of LV mass index (LVMi) regression on long-term clinical outcomes in severe aortic stenosis (AS) patients without significant PVR after TAVR.

METHODS

Of 412 patients who underwent TAVR, 146 who had LV hypertrophy (LVMi ≥115 g/m² for men and ≥ 95 g/m² for women) at baseline and were alive at one year after TAVR were enrolled. The primary outcome was cardiovascular deaths and the impact of LVMi regression on clinical outcomes were examined. The patients with significant PVR were excluded.

RESULTS

During a median follow-up of 40 months (interquartile range, 26-58 months), 9 (6.2%) cardiovascular deaths, 21 (14.4%) all-cause deaths, and 9 (6.2%) hospitalizations occurred. In the multivariable analysis, the percentage change of LVMi was an independent predictor of cardiovascular deaths (adjusted hazard ratio [HR], 1.03; 95% confidential interval [CI], 1.01-1.05; P = 0.010), and composite outcome of cardiovascular deaths and rehospitalization for heart failure (adjusted HR, 1.02; 95% CI, 1.00-1.04; P = 0.022). Baseline LVMi, eccentric hypertrophy, and TAVR-induced left bundle branch block were independently associated with LVMi regression.

CONCLUSIONS

In patients with severe AS who received successful TAVR without significant PVR, the degree of LVMi regression is an independent predictor of postoperative outcomes after TAVR.

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

BACKGROUND AND OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Rigorous patient-prosthesis matching of Perimount Magna aortic bioprosthesis

Background

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

Methods

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

Results

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

Conclusions

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

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.

Predictors of the size of prosthetic aortic valve and in-hospital mortality in aortic valve replacement

Purpose:

We hypothesized that gender, age, aortic root dimension, blood group and Left Ventricular End Diastolic and Systolic Diameters may have a significant correlation with the size of mechanical valve used.

Methods:

We included 48 patients retrospectively who had been operated at a single tertiary hospital. All patients with aortic stenosis or regurgitation were included in the study. Patients who had undergone previous cardiac surgery or concomitant surgical procedures, such as coronary artery bypass grafting, were excluded from the study.

Results:

The median size of the valves used in males (23mm) and females (21mm) were significantly different (P = 0.001). Size of the valve used was significantly associated with Left Ventricular End Systolic Diameter (LVESD) (r = 0.327, P = 0.007) and aortic root dimension (r = 0.526, P < 0.001). Moreover, significantly higher values of LVESD were observed in the expired patients (P = 0.023).

Conclusion:

This study shows that aortic root dimension and gender may be important predictors for the size of the prosthetic aortic valve used in aortic valve replacement. Our study also concludes that LVESD has significant relationship with in-hospital mortality. However, more long term clinical trials should be conducted to confirm these relationships.

Transaortic edge-to-edge mitral valve repair and left ventricular myectomy

Systolic anterior motion of mitral anterior leaflet is a serious clinical condition and it is hard to control medically. Alfieri edge-to-edge repair has been thought one of the useful techniques to improve abnormal anterior systolic motion with hypertrophic obstructive cardiomyopathy. Here, we present a 71-year-old lady who had the left ventricular outflow tract obstruction, severe mitral valve regurgitation with systolic anterior motion. The patient had a history of aortic valve replacement 5 years ago. She was successfully treated with transaortic edge-to-edge mitral valve plasty and myectomy of the left ventricle. Postoperative course was uneventful.

Aortic valve replacement with smaller valve size

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

Impact of Prosthesis-Patient Mismatch on Long-Term Survival in Patients With Small St Jude Medical Mechanical Prostheses in the Aortic Position

Background— The impact of aortic prosthesis-patient mismatch (P-PtM) on long-term survival is unclear.

Methods and Results— Between 1985 and 2000, 388 patients at Mayo Clinic in Rochester, Minn, underwent aortic valve replacement (AVR) with 19- or 21-mm St Jude Medical prostheses and had transthoracic echocardiography within 1 year after AVR. Mean age of patients was 62±13 years; 69% were female. Prosthesis effective orifice area (EOA) was derived from the continuity equation. P-PtM was classified as severe (indexed EOA ≤0.60 cm 2 /m 2 ), moderate (0.60 cm 2 /m 2 <indexed EOA≤0.85 cm 2 /m 2 ), or not hemodynamically significant (indexed EOA >0.85 cm 2 /m 2 ). P-PtM was severe in 66 patients (17%), moderate in 168 (43%), and not hemodynamically significant in 154 (40%). Patients with severe P-PtM had a significantly larger body surface area ( P <0.0001), higher mean gradient ( P <0.0001), lower preoperative ( P <0.0001) and postoperative ( P <0.0001) ejection fractions, and lower stroke volume ( P <0.0001) and more often received a 19-mm prosthesis ( P =0.0008) than patients with moderate or no hemodynamically significant mismatch. For patients with severe mismatch, 5-year survival rates (72±6%) and 8-year survival rates (41±8%) were significantly less than for patients with moderate mismatch (80±3% and 65±5%; P =0.026) or no hemodynamically significant mismatch (85±3% and 74±5%; P =0.002). On multivariate analysis after adjustment for other predictors of outcome, severe mismatch was associated with higher mortality (hazard ratio 2.18; 95% confidence interval 1.24 to 3.85; P =0.007) and higher incidence of congestive heart failure (hazard ratio 3.1; 95% confidence interval 1.3 to 7.4; P =0.009) than no hemodynamically significant mismatch.

Conclusions— Severe P-PtM is an independent predictor of higher long-term mortality and congestive heart failure in patients with small St Jude Medical aortic valve prostheses. For patients undergoing AVR who are at risk of severe mismatch, every effort should be made to use a larger prosthesis or to consider a prosthesis with a larger EOA.

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.

Hemodynamic Comparison of Bioprostheses for Complete Supra-Annular Position in Patients With Small Aortic Annulus

OBJECTIVES

The present study evaluates complete supra-annular bioprostheses in patients with an aortic annulus of 18 to 23 mm in diameter.

BACKGROUND

Aortic valve replacement in patients with small aortic annulus using stented bioprostheses is often associated with unsatisfactory hemodynamic results and high incidence of patient-prosthesis mismatch.

METHODS

Between February 2000 and January 2004, 156 patients with aortic valve disease and an aortic annulus of 18 to 23 mm in diameter received the stented bovine Soprano (Sorin Biomedica Cardio, Saluggia, Italy) (n = 18), Perimount (Edwards Lifesciences, Irvine, California) (n = 52), Perimount Magna (Edwards Lifesciences) (n = 42), or the stented porcine Mosaic (Medtronic Inc., Minneapolis, Minnesota) (n = 44) bioprostheses. Intraoperatively, the surgeon measured the aortic annulus diameter by inserting a hegar dilator. Thus, postoperative hemodynamic results could be referred to the patient's aortic annulus diameter instead of referring the results to the labeled valve size. This allows for objective comparisons between different valve types.

RESULTS

There was no significant difference in hemodynamic results between the different valve types in patients with an aortic annulus 18 to 20 mm. In patients with an annulus 21 to 23 mm, the Magna was significantly superior to the other investigated devices in mean pressure gradient, effective orifice area, and incidence of patient-prosthesis mismatch. There was no significant difference between the complete supra-annular bioprostheses Mosaic and Soprano and the intra-supra-annular Perimount valve.

CONCLUSIONS

In patients with an aortic annulus of 18 to 20 mm in diameter, hemodynamic performance is independent of the implanted stented valve type and the annular position. Root enlargement or stentless valves may be beneficial alternatives. Patients with annulus diameter 21 to 23 mm benefit from the Magna in complete supra-annular position leading to superior hemodynamic results.

Experimental study of a multiplaned mechanical aortic valve using bovine aorta

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

Comparative Evaluation of Small-Size Sorin Slimline and St. Jude HP Heart Valve Prostheses

BACKGROUND

The Sorin Slimline aortic valve prosthesis, a modification of the Sorin Bicarbon valve with increased internal orifice diameter and geometric orifice area, may show improved hemodynamic performance when compared with other previous prosthesis, but so far no comparison study has been reported.

METHODS

Between May 1999 and March 2002, 80 patients (31 to 81 years of age; mean, 65 years) with a small aortic annulus were randomized to undergo aortic valve replacement with either the Sorin Slimline (n = 40) or St. Jude High Performance (n = 40) valve prosthesis. Clinical and echocardiographic Doppler follow-up was performed at 3 to 4 weeks, and 6 and 12 months postoperatively.

RESULTS

One patient died of non-valve-related causes 9 months after operation. Mean and peak pressure gradients at 6 and 12 months in the Sorin Slimline valve were lower than in the St. Jude High Performance valve for both size 19 and 21 mm. Effective orifice area and effective orifice area index were not significantly different. There was a significant (p = 0.0001) reduction in left ventricular mass and left ventricular mass index between preoperative measurements and at 12 months after surgery for both valves, but there was no difference (p = 0.27) between the Sorin Slimline and St. Jude High Performance valve prosthesis at any other follow-up period. Clinical results showed similarly good results with both valves.

CONCLUSIONS

No clinically significant difference in the hemodynamics of both valves was appreciated; patients with a Sorin Slimline valve exhibited statistically significantly lower pressure gradients, but the small differences in effective orifice area and effective orifice area index did not reach significance. A significant left ventricular mass regression was observed with both valve models. Both prostheses provided a satisfactory clinical outcome.

Preoperative moderate to severe diastolic dysfunction: A novel Doppler echocardiographic long-term prognostic factor in patients with severe aortic stenosis

OBJECTIVE

We studied long-term outcomes in severe aortic stenosis and the importance of prosthesis type (mechanical vs biologic) and size, preoperative left ventricular ejection fraction, diastolic function, and left ventricular mass.

METHODS

Patients undergoing valve replacement from 1991 to 1993 (n = 399, 45% women) were included. The diastolic function was evaluated by integrating mitral and pulmonary venous flow data with Doppler echocardiography. The patients were classified as having either normal diastolic function to mild diastolic dysfunction or moderate to severe diastolic dysfunction. Left ventricular ejection fraction and the diastolic function category were incorporated together with age, sex, and time since operation into a Poisson regression model with death as the end point. Prosthesis type and size and left ventricular mass were also investigated.

RESULTS

The age (mean +/- SD) was 71 +/- 9 years, and the overall survival after 12 years was 50%. Although markedly reduced during the initial 6-month period, mortality risk subsequently increased more than could be explained by age (hazard ratio of 1-year difference = 1.12, P = .0005). The moderate to severe diastolic dysfunction pattern independently predicted late mortality (hazard ratio = 1.72, P = .0038), whereas left ventricular ejection fraction did not (hazard ratio = 0.99, P = .18). The prognostic importance of moderate to severe diastolic dysfunction did not diminish with time; on the contrary, it tended to increase. Mortality after 12 years was not predicted by left ventricular mass (P = .66), prosthesis type (P = .57), or prosthesis size (P = .58).

CONCLUSION

This study reveals that moderate to severe diastolic dysfunction in patients with aortic stenosis is an independent predictor of late mortality after valve replacement and that its importance does not decrease with time. Our findings may suggest that moderate to severe diastolic dysfunction implies nonreversible myocardial changes that negatively affect survival.

Comparison of transprosthetic mean pressure gradients between Medtronic Hall and ATS valves in the aortic position

AIM OF THE STUDY

Several studies have shown the inferior performance of small prostheses in the narrow aortic root. However, modern low-profile mechanical prostheses have improved hemodynamic performance characteristics. By measuring the transprosthetic pressure gradient in vivo, we were able to characterize the hemodynamic features of two prostheses: the ATS Medical (ATS) and the Medtronic Hall (MH) valves.

METHODS

From October 1994 to April 2002, 113 patients received an aortic valve replacement (AVR) with either an ATS or a MH valve. The transprosthetic pressure gradients, calculated from a simplified Bernoulli equation during immediate postoperative Doppler echocardiographic examination, were compared for differently sized prostheses with respect to body surface area (BSA).

RESULTS

The mean pressure gradients and the mean BSAs were: 27.8 +/- 14.8 mm Hg and 1.50 +/- 0.10 m(2) in ATS 19 mm (n = 7), 20.4 +/- 8.5 mm Hg and 1.54 +/- 0.11 m(2) in ATS 21 mm (n = 22), 13.0 +/- 5.7 mm Hg, 1.70 +/- 0.13 m(2) in ATS 23 mm (n = 22), 10.9 +/- 3.5 mm Hg and 1.81 +/ -0.16 m(2) in ATS 25 mm (n = 19), 9.3 +/- 0.6 mm Hg and 1.72 +/- 0.17 m(2) in ATS 27 mm (n = 4), 13.5 +/- 6.5 mm Hg and 1.54 +/- 0.13 m(2) in MH 20 mm (n = 9), 10.9 +/- 4.7 mm Hg and 1.64 +/- 0.15 m(2) in MH 22 mm (n = 22), 9.3 +/- 3.1 mm Hg and 1.72 +/- 0.12 m(2) in MH 24 mm (n = 7).

CONCLUSIONS

With the exception of the ATS 19-mm valve, the variously sized prostheses have acceptable transprosthetic pressure gradient measurements. In addition, even-sized MH valves (20 and 22 mm) with a thinner sewing cuff showed better hemodynamic performances than similarly sized ATS valves.

Impact of Valve Prosthesis-Patient Mismatch on Left Ventricular Mass Regression Following Aortic Valve Replacement

BACKGROUND

Valve prosthesis-patient mismatch is a frequent problem in patients undergoing aortic valve replacement and its main hemodynamic consequence is to generate high transvalvular gradients through normally functioning prosthetic valves. The persistence of high gradients may hinder or delay the regression of left ventricular hypertrophy after aortic valve replacement.

METHODS

The aim of the study was to determine the impact of prosthesis-patient mismatch on the postoperative regression of left ventricular mass. Left ventricular mass was measured by Doppler echocardiography in 109 patients undergoing aortic valve replacement with a single type of bioprosthesis (Carpentier-Edwards Perimount) for pure aortic stenosis. Prosthesis-patient mismatch was defined as a projected indexed effective orifice area less than 0.90 cm2/m2. On this basis, 58/109 (53.2%) patients had prosthesis-patient mismatch.

RESULTS

There was a good correlation (r = 0.61, p < 0.001) between the postoperative mean transprosthetic gradient and the projected indexed effective orifice area. The absolute and relative left ventricular mass regression was significantly (p = 0.002 and p = 0.01, respectively) lower in patients with prosthesis-patient mismatch (-48 +/- 47 g, -17% +/- 16%) compared to those with no prosthesis-patient mismatch (-77 +/- 49 g, -24% +/- 14%). In multivariate analysis, a larger projected indexed effective orifice area, female gender and a higher preoperative left ventricular mass are independent predictors of greater left ventricular mass regression.

CONCLUSIONS

This study shows that in patients with pure aortic stenosis prosthesis-patient mismatch is associated with lesser regression of left ventricular hypertrophy after aortic valve replacement. These findings may have important clinical implications given that prosthesis-patient mismatch is frequent in these patients.

Serial Doppler echocardiographic evaluation of small-sized sorin bicarbon prostheses

OBJECTIVE

The Sorin Bicarbon prosthesis (Sorin Biomedica, Saluggia, Italy) is a bileaflet valve with curved-profile leaflets, a rolling hinge mechanism, and a pyrolytic carbon-coated titanium alloy housing and sewing ring. Although the Sorin Bicarbon prosthesis has been implanted in greater than 80,000 patients, and reference values on the hemodynamic performance of valve prostheses are needed to avoid patient-prosthesis mismatch, few Doppler echocardiographic data are available on the prosthesis in the aortic position. The aim of this study is to provide a detailed echocardiographic evaluation of the hemodynamic performance and regression of left ventricular hypertrophy after aortic valve replacement with the Sorin Bicarbon prosthesis.

METHODS

The study included 182 patients who received a 21-mm (n = 61) or 23-mm (n = 121) Sorin Bicarbon prosthesis for pure or prevalent aortic stenosis who underwent serial echocardiograms at 3, 6, and 12 months after aortic valve replacement.

RESULTS

Mean and peak gradients significantly decreased (P <.001) during follow-up to values of 12 +/- 3 and 22 +/- 6 mm Hg for the 21-mm prosthesis and values of 11 +/- 4 and 19 +/- 6 mm Hg for the 23-mm prosthesis at 1 year. Left ventricular mass index showed a 17% decrease to 120 +/- 27 g/m(2) in recipients of the 21-mm prosthesis (P <.001) and a 21% decrease to 123 +/- 29 g/m(2) in recipients of the 23-mm prosthesis (P <.001). A larger prosthesis size was the only predictor of a higher left ventricular mass index regression. Among recipients of the 21-mm prosthesis, body surface area of greater than 1.85 m(2) was associated with a lower regression of left ventricular mass index. The effective orifice area index was 1.00 +/- 0.11 and 1.08 +/- 0.14 cm(2)/m(2) in recipients of the 21-mm and 23-mm prostheses, respectively.

CONCLUSIONS

Size 21 mm and 23 mm Sorin Bicarbon prostheses show low transprosthetic gradients, with significant reduction of left ventricular mass index during the first postoperative year. The reported effective orifice areas might be useful for aortic valve replacement in patients with a small aortic annulus to avoid patient-prosthesis mismatch.

A comparison of the in vivo performance of the 19-mm St. Jude Medical Hemodynamic Plus and 21-mm standard valve

BACKGROUND

In the present study we analyzed the in vivo performance of the 19-mm St. Jude Medical Hemodynamic Plus aortic prosthesis (19HP), evaluated the midterm performance of 19HP in the aortic position, and compared the implantability and hemodynamic characteristics of this valve with those of the 21-mm standard St. Jude Medical valve (21SD) in adult patients with aortic stenosis and a narrowed aortic annulus.

METHODS

From February 1994 to December 1999, 60 patients who underwent isolated aortic valve replacement with either the 19HP (n = 31) or the 21SD (n = 29) were studied. Comparison between the two models included analysis of early and late mortality and morbidity. Pre- and postoperative echocardiography was performed in all patients to evaluate and compare the hemodynamic performance of both prosthetic valves. The postoperative serum lactic dehydrogenase activity was measured in both groups of patients as an indicator of hemolysis.

RESULTS

The mean body surface area was 1.46 +/- 0.16 m2 in the 19HP group and 1.49 +/- 0.13 m2 in the 21SD group (p = 0.1577). Other than female dominance in the 19HP group, there was no statistically significant difference between the two groups in terms of preoperative variables (age, preoperative pressure gradients, and New York Heart Association functional class). The average postoperative peak pressure gradient was 23.3 +/- 10.5 mm Hg in the 19HP group and 27.9 +/- 9.9 mm Hg in the 21SD group (p = 0.0666). There was no hospital death in either group. Six-year follow-up was completed in both groups of patients. Late death occurred in 1 patient in the 19HP group (1.09% per patient-year). Actuarial survival at 6 years was 92.3% +/- 7.4% in the 19HP group, and 100% in the 21SD group (p = 0.33). The linearized complication rate was 1.09% per patient-year and 1.02% per patient-year for thromboembolism, and 1.09% per patient-year and 1.02% per patient-year for anticoagulant-related hemorrhage in the 19HP group and the 21SD group, respectively. Freedom from all complications at 6 years did not show any significant difference between the two groups (p = 0.54). Although left ventricular mass indices decreased significantly after aortic valve replacement in both groups (19HP group, p = 0.0002; 21SD group, p = 0.0006), there were no significant differences in the two indices between the groups after aortic valve replacement (p = 0.999). There was no significant difference in the lactic dehydrogenase level between the two groups (p = 0.4915).

CONCLUSIONS

In vivo hemodynamic performance of the 19HP valve as well as the early and intermediate clinical outcome up to 6 years was satisfactory and corresponded closely to that of the 21SD valve in adult patients. The 19-mm Hemodynamic Plus model can be recommended in patients with a measured 19-mm annulus and this valve will minimize the need for the aortic annular enlargement procedure.

Routine enlargement of the small aortic root: a preventive strategy to minimize mismatch

BACKGROUND

We routinely use aortic root enlargement (ARE) as part of one strategy to avoid prosthesis-patient mismatch in patients with relatively small aortic roots who are undergoing aortic valve replacement (AVR).

METHODS

We performed a retrospective review of 657 consecutive stented AVR patients at a single institution between 1995 to 2001. Of these, 114 (17%) patients underwent ARE. Root enlargement was selectively performed in patients at risk for prosthesis-patient mismatch, defined as calculated projected indexed effective orifice area (iEOA) less than 0.85 cm2/m2. This involved extension of the aortotomy between the left and noncoronary cusps, valve implantation, and Dacron patch closure of the aorta, thus permitting replacement with a valve size appropriate to body surface area.

RESULTS

The mean age of ARE patients was 72.5 +/- 11.0 years, with 32% aged 80 years or more. Of the patients, 61% were female and 27% had undergone previous cardiac operations. Combined procedures included coronary bypass in 57 patients and mitral repair or replacement in 24. The prevalence of mismatch was less than 3%. The ARE required an average of 19 minutes of additional aortic clamp time. The 30-day mortality was 0.9%. Logistic regression showed perfusion time to be the only independent predictor of mortality.

CONCLUSIONS

Our results show that ARE can be performed readily and with minimal added risk relative to standard AVR. We also present a preventive strategy to minimize mismatch predicted at time of operation from the reference value of effective orifice area for a given prosthesis and the patient's size. This includes use of ARE to enhance the potential benefit of AVR.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Complete aortic root replacement in patients with small aortic annulus

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Four year follow up of aortic valve replacement for isolated aortic stenosis: a link between reduction in pressure overload, regression of left ventricular hypertrophy, and diastolic function

OBJECTIVE

To evaluate changes in left ventricular function and the impact of ventricular hypertrophy and pressure gradient early and late after aortic valve replacement in patients with isolated aortic stenosis.

DESIGN

41 patients with isolated aortic stenosis and normal systolic function underwent cross sectional and Doppler echocardiography two months before and two weeks and four years after aortic valve replacement.

RESULTS

Early after the operation, left ventricular mass index (mean (SD)) decreased from 187 (44) g/m(2) to 179 (46) g/m(2), because of a reduction in end diastolic diameter (p < 0.05). Aortic pressure gradients were reduced, as expected. Isovolumic relaxation time was reduced from 93 (20) ms to 78 (12) ms, and deceleration time from 241 (102) ms to 205 (77) ms (p < 0.05). At four years, left ventricular mass index was further reduced to 135 (30) g/m(2) (p < 0.01) as a result of wall thickness reduction in the interventricular septum (from 14 (1.6) mm to 12 (1.4) mm, p < 0.01) and the posterior wall (from 14 (1.6) mm to 12 (1.3) mm, p < 0.01). Diastolic function, expressed by a reduction in isovolumic relaxation time from 93 (20) ms to 81 (15) ms (p < 0.01) and deceleration time from 241 (102) ms to 226 (96) ms (p < 0.05), remained improved. Prolonged isovolumic relaxation time was associated with significant septal and posterior wall hypertrophy (wall thickness > 13 mm) (p < 0.05), whereas prolonged deceleration time was related to high residual gradient (peak gradient > 30 mm Hg ) (p < 0.01).

CONCLUSIONS

Left ventricular diastolic function improves early after surgery for aortic stenosis in parallel with the reduction in the aortic gradient. However, prolongation of Doppler indices of myocardial relaxation and ventricular filling is observed in patients with significant left ventricular hypertrophy and a residual pressure gradient early after surgery. At four years postoperatively, diastolic function remains improved.

Hemodynamic and clinical impact of prosthesis-patient mismatch in the aortic valve position and its prevention

Prosthesis-patient mismatch is present when the effective orifice area of the inserted prosthetic valve is less than that of a normal human valve. This is a frequent problem in patients undergoing aortic valve replacement, and its main hemodynamic consequence is the generation of high transvalvular gradients through normally functioning prosthetic valves. The purposes of this report are to present an update on the concept of aortic prosthesis-patient mismatch and to review the present knowledge with regard to its impact on hemodynamic status, functional capacity, morbidity and mortality. Also, we propose a simple approach for the prevention and clinical management of this phenomenon because it can be largely avoided if certain simple factors are taken into consideration before the operation.

Aortic valve replacement: is valve size important?

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Performance of 21-mm size perimount aortic bioprosthesis in the elderly

BACKGROUND

Aortic valve replacement in elderly patients with a small aortic annulus may pose difficult problems in terms of prosthesis selection. We have evaluated the hemodynamic performance of the 21-mm Carpentier-Edwards Perimount bioprosthesis implanted in elderly patients.

METHODS

From July 1996 to June 1998, 19 patients (17 women and 2 men, mean age 76+/-4 years and mean body surface area 1.73+/-0.13 m2), had aortic valve replacement with a 21-mm Carpentier-Edwards Perimount bioprosthesis. The hemodynamic performance of the valve was evaluated in 16 patients, who completed at least a 6-month follow-up interval, with transthoracic color-Doppler echocardiography with particular reference to peak and mean transprosthetic gradients, effective orifice area index, and regression of left ventricular mass index.

RESULTS

There were no late deaths and no major postoperative complications. At a mean follow-up of 12+/-7 months, compared to discharge, all patients showed clinical improvement with a significant reduction of peak gradient (from 23+/-4 to 21+/-6 mm Hg, p = 0.04) and left ventricular mass index (from 181+/-23 to 153+/-20 g/m2; p<0.001), whereas mean gradient (from 13+/-3 to 13+/-4 mm Hg, p = not significant) and effective orifice area index (from 1.12+/-0.34 to 1.13+/-0.28 cm2/m2, p = not significant) remained substantially unchanged.

CONCLUSIONS

The use of a 21-mm Carpentier-Edwards Perimount bioprosthesis is associated with low transprosthetic gradients and significant reduction in left ventricular hypertrophy after aortic valve replacement. The results of our study suggest that a 21-m Carpentier-Edwards Perimount bioprosthesis should be considered a valid option in elderly patients with aortic valve disease and a small aortic annulus.

Changes in left ventricular mass and function after aortic valve replacement: a comparison between stentless and stented bioprosthetic valves

The objective of this study was to compare stentless bioprostheses with stented bioprostheses with regard to the postoperative changes in left ventricular (LV) mass and function. Forty patients with aortic stenosis undergoing valve replacement with a stentless (20 patients) or a stented (20 patients) bioprosthesis were evaluated early (baseline), 1 year, and 2 years after operation. Left ventricular mass index was calculated with the corrected American Society of Echocardiography formula. The relative changes between end-diastole and end-systole in LV mid-wall radius, length, and volume (ejection fraction) were determined with a previously validated model for dynamic geometry of the left ventricle. Overall, a significant decrease was found in LV mass index (from 155 +/- 30 to 112 +/- 23 g/m(2); P <.001) and a significant increase in longitudinal shortening (from 0.12 +/- 0.11 to 0.22 +/- 0.08; P <. 001), and ejection fractions (from 0.67 +/- 0.11 to 0.71 +/- 0.10; P =.017). No significant change was found in the mid-wall radius shortening fraction. Two years after surgery, the extent of LV mass regression was greater in stentless bioprostheses (-51 +/- 18 vs -35 +/- 17 g/m(2); P =.01), though the average mass index was similar in both groups (114 +/- 26 vs 110 +/- 20 g/m(2)). Also at 2 years, the longitudinal shortening fraction was greater in patients with a stentless bioprosthesis (0.25 +/- 0.07 vs 0.18 +/- 0.08; P =.03). In conclusion, this study suggests that the superior hemodynamic performance of stentless bioprostheses may have some benefits with regard to LV mass regression and function after aortic valve replacement. The significance of these benefits in terms of prognosis remains to be determined.

Impact of small prosthetic valve size on operative mortality in elderly patients after aortic valve replacement for aortic stenosis: does gender matter?

OBJECTIVE

Ideal management of the elderly patient with a small aortic root remains controversial. This retrospective analysis was performed to determine whether small prosthetic valve size is related to outcome in patients 70 years of age or older undergoing aortic valve replacement for aortic stenosis.

METHODS

Between December 1991 and July 1998, 366 patients 70 years of age or older (median age 77 years, range 73-81 years, 49% male) underwent isolated aortic valve replacement or aortic valve replacement with coronary bypass grafting with standard Carpentier-Edwards bovine pericardial valves (Baxter Healthcare Corp, Edwards Division, Santa Ana, Calif) (n = 277; 76%) or St Jude Medical mechanical valves (St Jude Medical, Inc, St Paul, Minn) (n = 89; 24%). Propensity scoring and multivariable regression models were used to evaluate the risks associated with implantation of 19-mm valves.

RESULTS

Operative mortality was 16.7% (17/102) in patients who received 19-mm valves and 3% (8/264) among those receiving >/=21-mm valves (P </=.0005). The univariable odds ratio for operative death for 19-mm versus >/=21-mm valves was 6.4 (95% CI 2.7, 15.4; P </=.0005). In the final multivariable model, receipt of a 19-mm valve alone was not a statistically significant predictor of operative death (odds ratio 2. 1; 95% CI 0.7, 6.4; P =.21). However, the combination of male sex and 19-mm valve resulted in a significant risk of operative death (4/9 patients; odds ratio 17.5; 95% CI 2.2, 139; P =.007). Use of a 19-mm valve was not related to late death in either the univariable (hazard ratio 1.0; 95% CI 0.5, 2.0; P =.95) or the multivariable analysis (hazard ratio 0.7; 95% CI 0.3, 1.8; P =.51).

CONCLUSIONS

Implantation of a standard 19-mm aortic valve in elderly men with aortic stenosis may be associated with an increased risk of operative mortality. A higher performance valve and/or a root enlargement procedure should be considered in men with a measured 19-mm anulus.

Haemodynamic performance of aortic pericardial bioprostheses and bileaflet prostheses at rest and during exercise: implications for the surgical management of patients with small aortic roots

OBJECTIVE

To determine the haemodynamic behaviour, at rest and during exercise, of aortic valve pericardial bioprostheses and different sizes of bileaflet prosthesis.

DESIGN

Observational study.

SETTING

Tertiary medical centre.

PATIENTS AND INTERVENTIONS

74 patients (33 women, 41 men; mean age 64 years) in whom 40 pericardial bioprostheses and 34 bileaflet prostheses sized 19, 21, or 23 mm had been implanted to replace aortic valves.

MAIN OUTCOME MEASURES

Doppler echocardiography at rest and at peak exercise, between 12 and 47 months after surgery.

RESULTS

All patients achieved a significant increase in heart rate, systolic blood pressure, and cardiac output with exercise. Transvalvar pressure fall, valve area, and left ventricular systolic and diastolic function indices also underwent significant changes with exercise. Reductions in peak and mean transvalvar pressure, at rest and at peak exercise, were greater in patients with small valves (p < 0.05). Valve areas and effective area index were greater in the patients with larger valves (p < 0.001). There were no significant differences between patients with mechanical and biological prostheses with regard to transvalvar pressure fall and valve areas at rest and at peak exercise.

CONCLUSIONS

19 mm and 21 mm aortic prostheses and bioprostheses continue to create significant obstruction, particularly with exercise.

Influence of aortic valve replacement, prosthesis type, and size on functional outcome and ventricular mass in patients with aortic stenosis

OBJECTIVES

Two years after surgery for severe aortic stenosis, we prospectively evaluated the influence of aortic valve replacement, as well as valve type (mechanical or stented biologic) and size, on functional status, left ventricular function, and regression of mass.

METHODS

Patients who received either a mechanical (n = 95) or a biologic valve (n = 42) were studied by echocardiography before the operation and after 2 years.

RESULTS

The percentage of patients with severe dyspnea decreased from 53% to 13% (P =.001). The cardiac index increased from mean 2.6 L/min per square meter (95% CI: 2.48-2. 72 L/min per square meter) to 3.1 L/min per square meter (95% CI: 2. 94-3.26 L/min per square meter; P =.001). The percentage of the patients with mild-to-moderate diastolic dysfunction decreased from 43% to 18% (P =.001). The left ventricular mass index was reduced by 42.4 g (95% CI: 35-50 g; P =.001). In comparison with biologic valves of the same size, mechanical valves produced a more pronounced reduction in mass index (overall difference 21.7 g; 95% CI: 37.1-6.4 g; P =.007) and a lower mean Doppler gradient (overall difference 4 mm Hg; 95% CI: 2-6 mm Hg; P =.0002).

CONCLUSIONS

Patients undergoing aortic valve replacement had an improvement in functional status, as well as systolic and diastolic left ventricular function, and a reduction in left ventricular mass index, irrespective of prosthesis size and type. Mechanical valves are somewhat less obstructive than stented bioprosthetic valves of the same size. They are also associated with a concomitantly more pronounced reduction of left ventricular mass.

The CarboMedics "Top-Hat" supraannular prosthesis

BACKGROUND

The CarboMedics "Top-Hat" supraannular prosthesis was designed to permit the implantation of a larger prosthesis.

METHODS

Between June 1993 and November 1996, 127 patients (average age, 61.8+/-10.2 years) received a CarboMedics "Top-Hat" supraannular aortic prosthesis. The average follow-up was 15.7 months, and all surviving patients underwent echocardiographic study. This group is compared with 656 patients in whom a standard CarboMedics prosthesis was implanted and also with 2,927 patients who received other aortic prostheses.

RESULTS

Using the standard and the supraannular sizers, there was an average increase of one size in favor of the supraannular prosthesis: 18.9+/-2.8 mm standard versus 20.8+/-2.6 mm supraannular (p < 0.005). For each prosthesis size (19 to 23 mm), the body surface area of the patients in whom a CarboMedics supraannular prosthesis was implanted was significantly smaller than that in those who received a CarboMedics standard prosthesis or any other model. Hospital mortality was 3.9%, and late mortality was 5.5%. The actuarial survival was 86.5%+/-3.9% at 42 months.

CONCLUSIONS

Using the CarboMedics supraannular prosthesis allows implantation of a larger prosthesis compared with the standard CarboMedics prosthesis or other models. This advantage is especially important in patients with a small aortic root.

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

BACKGROUND

We studied the effect of four different types of prosthetic aortic valves on time course and extent of regression of left ventricular hypertrophy after aortic valve replacement for aortic stenosis.

METHODS

Four groups of 10 patients each were randomly assigned to receive: (1) aortic homograft preserved in antibiotic solution at 4 degrees C, (2) Toronto stentless porcine valve, (3) Medtronic Freestyle stentless valve, or (4) Medtronic Intact aortic valve. The left ventricular mass index, effective orifice area index, and peak and mean transaortic gradients were measured by Doppler echocardiography before the operation and 8 months postoperatively.

RESULTS

The hemodynamic performance indices were much better for the homograft and stentless valves than for the stented one. The absolute left ventricular mass index reduction was greater in the homograft group compared with the Intact (p = 0.0004) and Toronto (p = 0.007) groups. The extent of percent left ventricular mass index reduction was greater only in the homograft group versus Intact group (p = 0.005). The multilinear regression analysis showed that the only predictors of a larger percentage of left ventricular mass index reduction were the homograft type, a higher valve size index, and a higher preoperative left ventricular mass index.

CONCLUSIONS

When a stentless or homograft aortic valve was used instead of a stented valve to replace a stenotic aortic valve there was more complete or at least faster regression of left ventricular hypertrophy. The hemodynamic performance of stentless porcine valves was similar to that of aortic homografts, nevertheless the aortic homografts preserved in antibiotic solution offered a faster regression of left ventricular hypertrophy during the same period of time.

The stentless Cryolife-O'Brien aortic porcine xenograft: a five-year follow-up

BACKGROUND

The 5-year follow-up of CryoLife-O'Brien stentless porcine aortic valve xenografts is presented.

METHODS

From August 1991 to August 1996, the valve was used in 366 patients. Patients' ages ranged from 18 to 90 years (mean, 73+/-6 years). Survivors were monitored with Doppler echocardiography before discharge, at 6 months, and then annually by the referring cardiologist. Operative and long-term mortality and morbidity were collected using the Edmunds guidelines for reporting morbidity and mortality after cardiac valvular operations.

RESULTS

The study was completed during a 6-month period with a 96.5% follow-up, comprising 999 patient-years for a mean follow-up period of 27 months (range, 3 to 64 months). Operative mortality was 6.5%. Linearized rates per patient-year for complications were as follows: structural valve deterioration (0%); thromboembolism (0.5%); prosthetic valve endocarditis (0.2%); valve reoperation (0.8%); and valve-related mortality (0.2%). Sixteen late deaths have occurred. The actuarial survival rate at 5 years was 83%+/-3.5%.

CONCLUSIONS

The Cryolife-O'Brien stentless valve has given excellent early hemodynamic and 5-year results.

Functional evaluation of the bileaflet mechanical valve in the aortic position using dobutamine-stress echocardiography: is a 23-mm prosthetic valve adequately large enough?

The issue of valve prosthesis-patient mismatch in small annular patients is still controversial. The hemodynamic function of bileaflet mechanical valves in the aortic position was examined using dobutamine-stress echocardiography. Forty-four patients were enrolled in the study and divided into 5 groups, according to prosthesis size, from 21 mm to 29 mm. The aortic peak pressure gradient (APG) increased significantly in all groups with dobutamine-stress and exceeded 50 mmHg in 83% of the 21-mm group, in 64% of the 23-mm group, and in 33% of the 25-mm group. The APG even exceeded 80 mmHg in 22% and 18% of the 21-mm and 23-mm groups, respectively. In these cases, the potential of 'valve prosthesis-patient mismatch' was considered. From the relationship between the APG and the prosthesis valve area index (VAI), 'critical VAIs' were found where patients were likely to enter the 'mismatch' status; that is, 1.22 and 1.77 cm2/m2, respectively, for the 5 and 10 microg/kg per min stages of dobutamine stress. This critical VAI range is useful in predicting the 'mismatch' patients preoperatively. Alternative procedures or prostheses should then be selected for them.

Regression of left ventricular hypertrophy after aortic valve replacement for aortic stenosis with different valve substitutes

OBJECTIVE

Stentless biologic aortic valves are less obstructive than stented biologic or mechanical valves. Their superior hemodynamic performances are expected to reflect in better regression of left ventricular hypertrophy. We compared the regression of left ventricular hypertrophy in 3 groups of patients undergoing aortic valve replacement for severe aortic stenosis. Group I (10 patients) received stentless biologic aortic valves, group II (10 patients) received stented biologic aortic valves, and group III (10 patients) received bileaflet mechanical aortic valves.

METHODS

Echocardiographic evaluations were performed before the operation and after 1 year, and the results were compared with those of a control group. Left ventricular diameters and function, left ventricular wall thickness, and left ventricular mass were assessed by echocardiography.

RESULTS

Group I patients had a significantly lower maximum and mean transprosthetic gradient than the other valve groups (P = .001). One year after operation there was a significant reduction in left ventricular mass for all patient groups (P < .01), but mass did not reach normal values (P = .05). Although the rate of regression in the interventricular septum and posterior wall thickness differed slightly among groups, their values at follow-up were comparable and still higher than control values (P = .002). The ratio between interventricular septum and posterior wall and the ratio between wall thickness and chamber radius did not change significantly at follow-up.

CONCLUSIONS

Because the number of patients was relatively small, we could not use left ventricular mass regression after I year to distinguish among patients undergoing aortic valve replacement for aortic stenosis by means of valve prostheses with different hemodynamic performances.

Aortic valve replacement for octogenarians: are small valves bad?

BACKGROUND

As the population ages, more octogenarians become candidates for aortic valve replacement. Many octogenarians, particularly women, have a small aortic annulus and there is uncertainty as to the optimal management of this situation in that age group.

METHOD

To examine this issue, we reviewed 248 octogenarians (mean age, 82.6 +/- 2.3 years; 58% men) who underwent primary isolated aortic valve replacement (n = 99), or aortic valve replacement and coronary revascularization (n = 149), between 1980 and 1995. Nineteen-millimeter valves were used in 26% of the patients.

RESULTS

In-hospital mortality was 8.9%, 5% for aortic valve replacement alone and 11.4% for aortic valve replacement and coronary revascularization. It was 12.5% for the 19-mm size valves compared with 7.7% for the bigger size valves (p = 0.24). Follow-up (mean interval, 4.4 years) demonstrated survival for all patients of 85%, 60%, and 30% and survival free from cardiovascular events of 80%, 45%, and 21% at 1, 5, and 10 postoperative years, respectively. Multivariate analysis identified triple-vessel disease and preoperative congestive heart failure as associated with increased risk for both in-hospital and late mortality (p < 0.05). Valve size did not influence late survival or event-free survival regardless of body surface area.

CONCLUSIONS

The use of small aortic valve prostheses in octogenarians does not adversely affect the incidence of early or late mortality or cardiac events.

Reversibility of cardiac dysfunction after valve replacement in elderly patients with severe aortic stenosis

BACKGROUND

The role of aortic valve replacement for aortic stenosis has not been fully defined in terms of the postoperative reversibility of cardiac dysfunction and pulmonary hypertension in elderly patients.

METHODS

Cardiac function, assessed by radioisotope ventriculography and catheterization data, was evaluated before and after operation, and their results were compared between preoperative and postoperative data in each group of younger patients (<69 years, group I, n = 29) and elderly patients (> or =70 years, group II, n = 21).

RESULTS

One month postoperatively the peak ejection rate determined by radioisotope ventriculography improved significantly in comparison with the preoperative value in elderly patients (preoperatively, 228 +/- 38 versus postoperatively, 319 +/- 116% end-diastolic volume per second, p < 0.05), although their preoperative peak ejection rate was severely depressed. The postoperative peak filling rate of the elderly group was not completely reversible to almost normal value, whereas that of the younger group was completely reversible. Early diastolic peak filling rate (one-third peak filling rate) was not reversible in both two groups. Pulmonary hypertension in the elderly patients was reversible to postoperative almost normal pulmonary artery pressure despite the severity of aortic stenosis (systolic pulmonary artery pressure preoperatively, 37 +/- 16 mm Hg versus postoperatively, 25 +/- 5 mm Hg, p < 0.02; diastolic pulmonary artery pressure preoperatively, 15 +/- 6 mm Hg versus postoperatively, 10 +/- 4 mm Hg, p < 0.05).

CONCLUSIONS

Both cardiac dysfunction, reflected by reduction of peak ejection rate, and pulmonary hypertension in elderly patients with severe aortic stenosis were reversed, reaching almost normal values 1 month after operation.

Aortic valve replacement with a small mechanical valve prosthesis--a clinical and echocardiographic study of a St Jude Medical valve prosthesis

The use of small aortic valve prostheses raises concerns about harmful effects of residual obstruction to left ventricular outflow. The present study was undertaken to examine long-term clinical and echocardiographic results in 193 patients who underwent isolated aortic valve replacement (AVR) with a St Jude Medical (SJM) valve of 25 mm or smaller. The study subjects comprised 128 male and 65 female patients with a mean age of 54.1 years. The patients were divided into 2 groups according to the size of the valve prosthesis used for AVR. Small valves (19 or 21 mm) were implanted in 49 patients (group S) and large valves (23 or 25 mm) were used in 144 patients (group L). The group S patients were mainly female, older, and had smaller body surface areas. There were no significant differences in early and late mortality in group S as compared with group L. Furthermore, there was no difference in the incidence of valve-related or cardiac, non-valve-related death, including the incidence of sudden death, between the 2 groups, and they enjoy a similar level of daily routine activity regardless of the valve size used. Left ventricular (LV) function (ejection fraction, fractional shortening, LV mass index, LV end-systolic volume index, and LV end-diastolic volume index) measured by echocardiography improved significantly and returned to normal values after AVR in both groups. Moreover, no significant differences were observed in the postoperative variables of the LV function. These results suggest that 19-mm and 21-mm SJM valves can be safely used for AVR in the majority of Japanese patients.

Aortic valve replacement with patch enlargement of the aortic annulus

BACKGROUND

Aortic annulus enlargement has long been advocated for the placement of valve prostheses larger than otherwise would have been possible. Little information exists, however, on the short- and long-term outcome of this surgical procedure.

METHODS

We performed a retrospective review of 530 patients enrolled in a registry for patients who underwent aortic valve replacement using the Hancock II bioprosthesis and were followed up prospectively over the course of 11 years at a single institution. In an effort to avoid prosthetic valve-patient mismatch, the aortic annulus was enlarged in 98 patients (18%). Short- and long-term outcome was analyzed.

RESULTS

Enlargement of the aortic annulus during aortic valve replacement increased the operative mortality rate from 3.5% to 7.1%, but this difference did not reach statistical significance (p = 0.10). The long-term survival of patients who had annulus enlargement was similar to that of patients who did not. Because there were differences in the clinical profile of patients who had annulus enlargement and those who did not, a case-control study was carried out. This study showed similar long-term survival, freedom from valve-related and cardiac death, and combined end points in the two groups of patients.

CONCLUSION

Aortic annulus enlargement increased the operative mortality of aortic valve replacement. However, patients who underwent enlargement of a small aortic annulus had long-term survival and freedom from cardiac and valve-related death comparable to those of patients who received larger aortic prostheses.

Extent and pattern of regression of left ventricular hypertrophy in patients with small size CarboMedics aortic valves

OBJECTIVE

To assess the extent and pattern of regression of left ventricular hypertrophy after valve replacement for aortic stenosis, we studied 26 patients receiving either 19 or 21 mm CarboMedics valves (group I, 13 patients) or either 23 or 25 mm CarboMedics valves (group II, 13 patients). The studies were done before the operation and after 3 years, and results were compared with those of 10 control patients.

METHODS

Left ventricular end-diastolic and end-systolic diameters and volumes, ejection fraction and fractional shortening, and interventricular septum and posterior wall thickness were measured. The ratio between interventricular septum and posterior wall thickness, the ratio between left ventricular wall thickness and left ventricular chamber radius, and the left ventricular mass were then calculated.

RESULTS

At follow-up there was a significant reduction in the left ventricular mass, interventricular septum, and posterior wall thickness for both patient groups (p < 0.01). However, only the posterior wall thickness reached normal values; the interventricular septum and the left ventricular mass indices were still significantly greater than in the control group (p < 0.01). Because of the incomplete regression of interventricular septal hypertrophy, the ratio between interventricular septum and posterior wall thickness was similar between both patient groups but it was significantly higher than in control subjects (p < 0.01). The ratio between wall thickness and chamber radius did not decrease significantly in group II patients, in whom it remained above the control values.

CONCLUSION

Having a bileaflet aortic prosthesis of one size larger did not seem to significantly influence the pattern and the extent of regression of left ventricular hypertrophy after an intermediate period of follow-up.

Event status of the Starr-Edwards aortic valve to 20 years: a benchmark for comparison

BACKGROUND

Considerable effort and expense has been invested in the evolutionary development of cardiac valvular prostheses with the goal of reducing or minimizing specific events related to these prostheses. It is important to measure any improvement achieved with such development by comparison against a historic standard. The Starr-Edwards caged-ball prosthesis model 1260 has been used for 30 years as the predominant or sole model of its kind for aortic valve replacement. This historic opportunity provides a benchmark for subsequent improvement and comparison of current prostheses.

METHODS

Between 1969 and 1991, 1,100 patients (median age, 57 years; 838 men and 194 women) underwent aortic valve replacement with or without coronary artery bypass grafting (aortic valve replacement, 964; aortic valve replacement plus coronary artery bypass grafting, 136) with the 1260 Starr-Edwards caged-ball prosthesis.

RESULTS

Operative mortality was 6.2% (68 patients). Univariate patient characteristics predictive of early mortality were female sex (p = 0.003), age (> 56 years; p = 0.002), recent operative interval (1985 to 1991 versus 1969 to 1976 or 1977 to 1984; p = 0.002), presence of atrial fibrillation (p = 0.001), and small valve size (7A to 8A = 19 to 21 mm; p < 0.001). Follow-up extended to 11,293 patient-years (mean, 24.8 years) and was 96.9% complete. Survival at 5, 10, 15, and 20 years for all patients including operative mortality was 76.6%, 59.6%, 44.9%, and 31.2%, respectively. Operative variables predictive of poor late survival were advanced New York Heart Association class (III or IV); (p = 0.0001), older age (> 56 years; p = 0.0001), and lower (< 0.56) ejection fraction (p = 0.0001). Freedom from thromboemboli and anticoagulant-related bleeding at 5 years was 90.8% and 98.7%, respectively. Univariate model for greater risk of late thromboemboli identified female sex (p = 0.04), older age (> 56 years; p = 0.0002), and New York Heart Association class III or IV (p = 0.0058), as risk factors. Multivariate analysis for thromboemboli demonstrated older age (p = 0.0007) and New York Heart Association class III or IV (p = 0.0041) as significant. Alternatively, univariate analysis for late bleeding found only the most recent operative interval (p = 0.009) as significant, and the rarity of events prevented a multivariate query. There were no valve failures.

CONCLUSIONS

The late results of survival and freedom from late anticoagulant-related bleeding or thromboemboli are excellent, especially in larger (9A and above) sizes, and with the long implant record comparable with more recent prostheses, the Starr-Edwards valve provides an excellent, safe, and durable alternative in the aortic position and provides a benchmark against which to compare other prostheses.

Influence of the size of aortic valve prostheses on hemodynamics and change in left ventricular mass: implications for the surgical management of aortic stenosis

Discussion of aortic valve replacement has primarily concerned the choice between tissue and mechanical prostheses. Less emphasis has been placed on prosthesis size. Despite technical advances increasing prosthesis orifice area, small valves implanted in the unenlarged aortic root may not be significantly less obstructive than the stenotic native valves they replace.

METHODS

In this work we studied 52 patients (31 women, 21 men; mean age 59.2 years) in whom valve prostheses sized 19, 21, 23, or 25 mm (30 bioprostheses and 22 tilting disc valves) had been implanted to replace stenotic aortic valves. Most patients with 19 or 21 mm prostheses were women. Doppler and conventional echocardiographic studies were performed in the 10 days preceding the operation and between 10 and 40 months (mean 18 months) after the operation. The patients receiving larger valve sizes had significantly larger body surface areas than those receiving smaller valve sizes (mainly women).

RESULTS

No significant differences were observed between preoperative and postoperative diameters or left ventricular systolic function parameters, but left ventricular mass and mass index decreased in all four groups (albeit nonsignificantly in the 19 mm group, and with less statistical significance in the 21 mm group than in the 23 and 25 mm groups). Postoperative peak and mean transvalvular pressure drops were significantly greater in the 19 mm group than in the other groups, and the 21 mm group had significantly greater transvalvular pressure drops than the 25 mm group. Postoperative effective valve area was significantly smaller in the 19 mm group than in the 21 mm group, and significantly smaller in the 21 mm group than in the 23 and 25 mm groups.

CONCLUSION

We conclude that despite undeniable recent improvements in the design of artificial heart valves, 19 mm aortic prostheses continue to create significant obstruction of the left ventricular outflow tract and, possibly as a consequence of this, fail to bring about significant reduction in left ventricular hypertrophy.