Factors affecting left ventricular remodeling after valve replacement for aortic stenosis. An overview

Left Ventricular Mass, Myocardial Structure, and Function in Severe Aortic Stenosis: an Echocardiographic and Cardiac Magnetic Resonance Imaging Study

In severe aortic stenosis (AS), there are conflicting data on the prognostic implications of left ventricular (LV) hypertrophy (LVH). We aimed to characterize the LV geometry, myocardial matrix structural changes, and prognostic stratification using cardiac magnetic resonance imaging (CMR) and echocardiography in subjects with severe AS with and without LVH. Consecutive patients who had severe isolated AS and sufficient quality echocardiography and CMR within 6 months of each other were evaluated for LVH, cardiac structure, morphology, and late gadolinium-enhancement imaging. Kaplan-Meier curves, linear models, and proportional hazards models were used for prognostic stratification. There were 93 patients enrolled (mean age 74 ± 11 years, 48% female), of whom 38 (41%) had a normal LV mass index (LVMI), 41 (44%) had LVH defined at CMR by LVMI >2 SD higher than normal, and 14 (15% of the total) with >4 SD higher than the reference LVMI (severely elevated). The Society of Thoracic Surgeons scores were similar among the LVMI groups. Compared with those with normal LVMI, patients with LVH had higher LV end-diastolic and end-systolic volumes, increased late gadolinium-enhancement burden, and lower LV ejection fraction. Most notably, CMR feature-tracking global radial strain, 2-dimensional speckle-tracking echocardiography global longitudinal strain, and left atrial reservoir function were significantly worse. On the survival analyses, LVMI was not associated with a composite of all-cause mortality and/or heart failure hospitalization. In conclusion, compared with normal LVMI, elevated LVMI was not associated with a higher risk of adverse outcomes.

Impact of Aortic Root Enlargement on Patients Undergoing Aortic Valve Replacement

BACKGROUND

Aortic root enlargement (ARE) can be an important adjunct for aortic valve replacement (AVR). This study compared outcomes of AVR with or without ARE.

METHODS

This was an observational study using an institutional database of AVRs from 2010 to 2020 comparing patients who underwent isolated AVR vs AVR with ARE (AVR+ARE). Kaplan-Meier survival estimation and Cox regression were performed.

RESULTS

Of 2371 patients, 2240 (94.5%) underwent isolated AVR and 131 (5.5%) underwent AVR+ARE. Patients who underwent AVR+ARE were more likely to be women and to be younger than those who underwent isolated AVR. Prosthesis size was smaller in patients undergoing AVR+ARE (23 mm [interquartile range {IQR}, 21-25] vs 25 mm [IQR, 23-25], P < .001), but indexed effective orifice area did not differ between the 2 groups. Operative mortality was comparable for AVR (2.3%) and AVR+ARE (3.8%, P = .28). Patients who underwent AVR+ARE had a longer length of stay (7 days [IQR, 6-13] vs 6 days [IQR 5-10], P < .001), were more likely to have acute kidney injury (6.1% vs 2.5%, P = .01), were more likely to require blood product transfusions (40.5% vs 27.6%, P < .001), and were more likely to require prolonged ventilation > 24 hours (16.0% vs 6.8%, P < .001). Rates of stroke, atrial fibrillation, permanent pacemaker, and reoperation were comparable between groups. Kaplan-Meier survival estimates were similar, and on multivariable regression AVR+ARE was not associated with an increased hazard of death as compared with AVR (hazard ratio, 1.09; 95% confidence interval, 0.81-1.46; P = .59).

CONCLUSIONS

ARE can be safely performed with isolated AVR and should be considered for patients with small annuli to avoid prosthesis-patient mismatch.

Surgical versus transcatheter aortic valve replacement: Impact of patient-prosthesis mismatch on outcomes

BACKGROUND

The hemodynamics of most prosthetic valves are often inferior to that of the normal native valve, and a significant proportion of patients undergoing surgical (SAVR) or transcatheter aortic valve replacement (TAVR) have high residual transaortic pressure gradients due to prosthesis-patient mismatch (PPM). As the experience with TAVR has increased and long-term outcomes are reported, a close look at the PPM literature is required in light of new evidence.

METHODS

For this review, we searched the Embase, Medline, and Cochrane databases from 2000 to 2022. Articles reporting PPM as an outcome following aortic valve replacements were identified and reviewed.

RESULTS

The impact of PPM on clinical outcomes in aortic valve replacement has not been clear as multiple studies failed to report PPM incidence. However, the PPM outcomes after SAVR vary more widely than after TAVR, ranging from 8% to 80% in SAVR and from 24% to 35% in TAVR. Incidence of severe PPM following redo SAVR ranges from 2% to 9% and following valve-in-valve TAVR is from 14% to 33%, however, while PPM is higher in valve-in-valve TAVR, patients had better survival rates.

CONCLUSIONS

The gap between valve performance and clinical outcomes in SAVR and TAVR could be reduced by carefully selecting patients for either treatment option. Understanding predictors of PPM can add to the safety, effectiveness, and increased survival benefit of both SAVR and TAVR.

Pressure Overload Activates DNA-Damage Response in Cardiac Stromal Cells: A Novel Mechanism Behind Heart Failure With Preserved Ejection Fraction?

Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous syndrome characterized by impaired left ventricular (LV) diastolic function, with normal LV ejection fraction. Aortic valve stenosis can cause an HFpEF-like syndrome by inducing sustained pressure overload (PO) and cardiac remodeling, as cardiomyocyte (CM) hypertrophy and fibrotic matrix deposition. Recently, in vivo studies linked PO maladaptive myocardial changes and DNA damage response (DDR) activation: DDR-persistent activation contributes to mouse CM hypertrophy and inflammation, promoting tissue remodeling, and HF. Despite the wide acknowledgment of the pivotal role of the stromal compartment in the fibrotic response to PO, the possible effects of DDR-persistent activation in cardiac stromal cell (C-MSC) are still unknown. Finally, this novel mechanism was not verified in human samples. This study aims to unravel the effects of PO-induced DDR on human C-MSC phenotypes. Human LV septum samples collected from severe aortic stenosis with HFpEF-like syndrome patients undergoing aortic valve surgery and healthy controls (HCs) were used both for histological tissue analyses and C-MSC isolation. PO-induced mechanical stimuli were simulated in vitro by cyclic unidirectional stretch. Interestingly, HFpEF tissue samples revealed DNA damage both in CM and C-MSC. DDR-activation markers γH2AX, pCHK1, and pCHK2 were expressed at higher levels in HFpEF total tissue than in HC. Primary C-MSC isolated from HFpEF and HC subjects and expanded in vitro confirmed the increased γH2AX and phosphorylated checkpoint protein expression, suggesting a persistent DDR response, in parallel with a higher expression of pro-fibrotic and pro-inflammatory factors respect to HC cells, hinting to a DDR-driven remodeling of HFpEF C-MSC. Pressure overload was simulated in vitro, and persistent activation of the CHK1 axis was induced in response to in vitro mechanical stretching, which also increased C-MSC secreted pro-inflammatory and pro-fibrotic molecules. Finally, fibrosis markers were reverted by the treatment with a CHK1/ATR pathway inhibitor, confirming a cause-effect relationship. In conclusion we demonstrated that, in severe aortic stenosis with HFpEF-like syndrome patients, PO induces DDR-persistent activation not only in CM but also in C-MSC. In C-MSC, DDR activation leads to inflammation and fibrosis, which can be prevented by specific DDR targeting.

Comparison of safety and haemodynamic performance between the Avalus™ stented aortic valve bioprosthesis and Magna™ valve in Japanese patients

Objectives

A new stented bovine pericardial valve (Avalus™) has been proven safe and effective with good hemodynamic performance in Western populations. However, its use in Japanese patients is poorly understood. We retrospectively compared the feasibility, safety, and valve haemodynamics between the Avalus™ and Magna™ valves in patients who underwent surgical aortic valve replacement (SAVR).

Methods

This study included 87 patients receiving an Avalus™ valve and 387 receiving a Magna™ valve. We evaluated adverse events, outcomes, and valve haemodynamics within 1 year postoperatively. There were no significant differences in any surgical risk scores.

Results

No in-hospital mortality occurred in the Avalus™ group, but two mortality events occurred in the Magna™ group. No pacemaker implantation for complete atrioventricular block was required in the Avalus™ group. There was no significant difference in in-hospital or clinical outcomes between the two groups until 1 year postoperatively. Left ventricular mass index reduction appeared to predominate in the Avalus™ over Magna™ group. There was no significant difference in the mean pressure gradient or effective orifice area of each valve size at 1 week or 1 year between the two groups, apart from the mean pressure gradient of the 23-mm valve at 1 week. Three patients (3.4%) in the Avalus™ group and 39 (10.8%) in the Magna™ group (p = 0.12) had severe patient–prosthesis mismatch at 1 week postoperatively.

Conclusions

The new Avalus™ stented aortic valve bioprosthesis was associated with good in-hospital outcomes and good valve functionality post-SAVR in Japanese patients.

Pattern Analysis of Left Ventricular Remodeling Using Cardiac Computed Tomography in Children with Congenital Heart Disease: Preliminary Results

OBJECTIVE

To assess left ventricular remodeling patterns using cardiac computed tomography (CT) in children with congenital heart disease and correlate these patterns with their clinical course.

MATERIALS AND METHODS

Left ventricular volume and myocardial mass were quantified in 17 children with congenital heart disease who underwent initial and follow-up end-systolic cardiac CT studies with a mean follow-up duration of 8.4 ± 9.7 months. Based on changes in the indexed left ventricular myocardial mass (LVMi) and left ventricular mass-volume ratio (LVMVR), left ventricular remodeling between the two serial cardiac CT examinations was categorized into one of four patterns: pattern 1, increased LVMi and increased LVMVR; pattern 2, decreased LVMi and decreased LVMVR; pattern 3, increased LVMi and decreased LVMVR; and pattern 4, decreased LVMi and increased LVMVR. Left ventricular remodeling patterns were correlated with unfavorable clinical courses.

RESULTS

Baseline LVMi and LVMVR were 65.1 ± 37.9 g/m² and 4.0 ± 3.2 g/mL, respectively. LVMi increased in 10 patients and decreased in seven patients. LVMVR increased in seven patients and decreased in 10 patients. Pattern 1 was observed in seven patients, pattern 2 in seven, and pattern 3 in three patients. Unfavorable events were observed in 29% (2/7) of patients with pattern 1 and 67% (2/3) of patients with pattern 3, but no such events occurred in pattern 2 during the follow-up period (4.4 ± 2.7 years).

CONCLUSION

Left ventricular remodeling patterns can be characterized using cardiac CT in children with congenital heart disease and may be used to predict their clinical course.

The role and clinical implications of diastolic dysfunction in aortic stenosis

Diastolic dysfunction in aortic stenosis results primarily from left ventricular hypertrophy and myocardial fibrosis due to chronically elevated left ventricular systolic pressure. Currently, diastolic dysfunction does not have an explicit clinical role in management of patients with aortic stenosis. Studies have shown that improvement in diastolic dysfunction follows left ventricular remodelling after aortic valve replacement and that it occurs gradually or incompletely. Retrospective studies suggest that advanced grades of diastolic dysfunction at baseline are associated with increased mortality and adverse events even after aortic valve replacement. Recent studies have also associated myocardial fibrosis, a hallmark of diastolic dysfunction, with worse outcomes. In addition, these results were independent of the degree of aortic stenosis or valve replacement. Indirect evidence of the role of diastolic dysfunction in aortic stenosis also comes from paradoxical low-flow, low-gradient aortic stenosis, where disproportionate left ventricular hypertrophy leads to underfilling of the left ventricle, low-flow state and is associated with worse prognosis. Lastly, a limited number of studies suggest that worse diastolic dysfunction at baseline is detrimental in patients who develop aortic regurgitation after transcatheteraortic valve replacement, due to superimposition of volume overload on a stiff left ventricle. Current major limitations in our understanding of the prognostic role of diastolic dysfunction are the lack of universally accepted classification schemes, its dependence on dynamic loading conditions and the lack of larger prospective studies.

Regression of left ventricular mass after implantation of the sutureless 3f Enable aortic bioprosthesis

Left ventricular hypertrophy in aortic stenosis is considered a compensatory response for the maintenance of systolic function but a risk factor for cardiac morbidity and death. We investigated the degree of left ventricular mass regression after implantation of the sutureless Medtronic 3f Enable Aortic Bioprosthesis. We studied 19 patients who, from May 2010 through July 2011, underwent isolated aortic valve replacement with the 3f Enable bioprosthetic valve, with clinical and echocardiographic follow-up at 6 months. The mean age was 77.1 ± 5.1 years (range, 68-86 yr); 14 patients were women (73.7%); and the mean logistic EuroSCORE was 15.4% ± 11.8%. Echocardiography was performed preoperatively, at discharge, and at 6 months' follow-up. The left ventricular mass was calculated by means of the Devereux formula and indexed to body surface area. The left ventricular mass index decreased from 146.1 ± 47.6 g/m(2) at baseline to 118.1 ± 39.8 g/m(2) at follow-up (P=0.003). The left ventricular ejection fraction did not change significantly. The mean transaortic gradient decreased from 57.3 ± 14.2 mmHg at baseline to 12.3 ± 4.6 mmHg at discharge and 12.2 ± 5.3 mmHg at follow-up (P <0.001), and these decreases were accompanied by substantial clinical improvement. No moderate or severe paravalvular leakage was present at discharge or at follow-up. In isolated aortic stenosis, aortic valve replacement with the 3f Enable bioprosthesis results in significant regression of left ventricular mass at 6 months' follow-up. However, this regression needs to be verified by long-term echocardiographic follow-up.

Gender difference in ventricular response to aortic stenosis: insight from cardiovascular magnetic resonance

Background

Although left ventricular hypertrophy (LVH) and remodeling is associated with cardiac mortality and morbidity, little is known about the impact of gender on the ventricular response in aortic stenosis (AS) patients. This study aimed to analyze the differential effect of gender on ventricular remodeling in moderate to severe AS patients.

Methods and Results

A total of 118 consecutive patients (67±9 years; 63 males) with moderate or severe AS (severe 81.4%) underwent transthoracic echocardiography and cardiovascular magnetic resonance (CMR) within a 1-month period in this two-center prospective registry. The pattern of LV remodeling was assessed using the LV mass index (LVMI) and LV remodeling index (LVRI; LV mass/LV end-diastolic volume) by CMR. Although there were no differences in AS severity parameters nor baseline characteristics between genders, males showed a significantly higher LVMI (102.6±29.1g/m² vs. 86.1±29.2g/m², p=0.003) and LVRI (1.1±0.2 vs. 1.0±0.3, p=0.018), regardless of AS severity. The LVMI was significantly associated with aortic valve area (AVA) index and valvuloarterial impedance in females, whereas it was not in males, resulting in significant interaction between genders (PInteraction=0.007/0.014 for AVA index/valvuloarterial impedance, respectively). Similarly, the LVRI also showed a significantly different association between male and female subjects with the change in AS severity parameters (PInteraction=0.033/<0.001/0.029 for AVA index/transaortic mean pressure gradient/valvuloarterial impedance, respectively).

Conclusion

Males are associated with greater degree of LVH and higher LVRI compared to females at moderate to severe AS. However, females showed a more exaggerated LV remodeling response, with increased severity of AS and hemodynamic loads, than males.

Left ventricular mass regression after two alternative sutureless aortic bioprostheses

OBJECTIVE

Left ventricular (LV) hypertrophy in aortic stenosis (AS) constitutes a risk factor for cardiac morbidity and mortality. The aim of this study was to investigate the degree of LV mass regression after aortic valve replacement (AVR) with two alternative sutureless self-expanding strategies: Perceval S (Sorin Group, Saluggia, Italy) (P) and 3f Enable (Medtronic, ATS Medical, Minneapolis, MN USA) (E) aortic bioprostheses.

METHODS

Between March 2010 and December 2011, 129 patients with symptomatic AS underwent AVR with the Perceval S or 3f Enable bioprostheses in two cardiac surgery departments (Massa, Italy; Nuremberg, Germany). We analyzed 45 patients in group P and 19 in group E undergoing isolated AVR with a 6-month follow-up. The LV mass was calculated using the Devereux formula and was indexed to body surface area.

RESULTS

Baseline patient characteristics showed no significant differences between the two groups. There were no in-hospital deaths. Two patients in group P died at follow-up versus zero in group E (P = 0.49). Mean LV mass index decreased from 146.6 (78) g/m at baseline to 123.3 (63) g/m at follow-up (P < 0.001) in group P and from 146.1 (47.6) g/m to 118.1 (39.8) g/m (P = 0.003) in group E, with no significant difference between the two groups (P = 0.315). This effect was accompanied by significant clinical improvement.

CONCLUSIONS

In isolated AS, AVR with sutureless bioprostheses is associated with a significant regression in LV mass at 6-month follow-up. No significant differences were present between the two alternative sutureless strategies. However, regression needs an evaluation with long-term echocardiographic examinations.

A critical review of hemodynamic changes and left ventricular remodeling after surgical aortic valve replacement and percutaneous aortic valve replacement

The introduction of transcatheter aortic valve replacement (TAVR) in clinical practice has widened options for symptomatic patients at high surgical risk; however, it is not known whether TAVR has equivalent or prolonged benefits in terms of left ventricular (LV) remodeling.

METHODS

To explore the relative hemodynamic benefits and postoperative LV remodeling associated with TAVR and surgical aortic valve replacement (SAVR), we performed a critical review of the available literature. A total of 67 studies were included in this systematic review.

RESULTS

There is at least equivalent if not slightly superior hemodynamic performance of TAVR over SAVR, and TAVR showed lower prosthesis-patient mismatch compared with SAVR. However, LV mass appears to regress to a greater degree after SAVR compared with TAVR. Aortic regurgitation, paravalvular in particular, is more common after TAVR than SAVR, although it is rarely more than moderate in severity. Improvements in diastolic function and mitral regurgitation are reported in only a handful of studies each and could not be compared across prosthesis types.

CONCLUSIONS

The published data support the hemodynamic comparability of SAVR and TAVR, with the higher incidence of prosthesis-patient mismatch in SAVR offset by higher incidence of paravalvular leak in TAVR. These results highlight the need for further studies focusing on hemodynamic changes after valve therapy.

Left ventricular mass regression after sutureless implantation of the Perceval S aortic valve bioprosthesis: preliminary results

OBJECTIVES

Left ventricular (LV) hypertrophy in aortic stenosis (AS) is considered a compensatory response helping maintain systolic function, but constitutes a risk factor for cardiac morbidity and mortality. The aim of this study was to assess the degree of LV mass regression after sutureless implantation of the Perceval S aortic valve bioprosthesis (Sorin Group, Saluggia, Italy).

METHODS

Between March 2010 and July 2012, 78 patients with symptomatic AS underwent isolated aortic valve replacement (AVR) with the Perceval bioprosthesis. Mean age was 77.1 ± 5.3 years, 46 patients were female (59%) and mean logistic EuroSCORE was 11 ± 7.5%. Echocardiography was performed preoperatively, at discharge, and at follow-up (mean 13.5 ± 7.3 months). LV mass was calculated using the Devereux formula and indexed to body surface area.

RESULTS

There was 1 in-hospital non-cardiac death and 3 late deaths. LV mass index decreased from 148.4 ± 46 g/m(2) at baseline to 119.7 ± 38.5 g/m(2) at follow-up (P = 0.002). No significant changes were observed in LV hypertrophy and/or relative wall thickness >0.42 as well as in LV ejection fraction. Mean aortic gradient decreased from 49.5 ± 15.8 mmHg at baseline to 11.6 ± 5.1 mmHg at discharge and 8.3 ± 4.4 mmHg at follow-up (P < 0.001), resulting in significant clinical improvement. No moderate or severe paravalvular leakage was observed at discharge and at follow-up.

CONCLUSIONS

In AS patients, isolated AVR with the Perceval sutureless bioprosthesis is associated with significant LV mass regression at 1-year follow-up. However, longer-term follow-up is necessary to confirm these findings.

Magnetic resonance imaging versus echocardiography to ascertain the regression of left ventricular hypertrophy after bioprosthetic aortic valve replacement: results of the REST study

OBJECTIVES

To compare the decrease in left ventricular mass index (LVMI) by magnetic resonance imaging (MRI) versus transthoracic echocardiography (TTE) after aortic valve replacement (AVR) for severe aortic stenosis with Epic and Epic Supra stented porcine bioprostheses (St Jude Medical, Inc, St Paul, Minn).

METHODS

This prospective multicenter study enrolled 149 patients who underwent AVR between January 2006 and February 2008. TTE and cardiac MRI measurements of LVMI were made at baseline and at 6 months of follow-up and were compared. Changes in mean pressure gradients were examined using TTE.

RESULTS

TTE measurements of LVMI were 48% to 63% higher than the MRI measurements. A decrease in LVMI from 137 ± 32 to 95 ± 16 g/m(2) with the Epic and from 139 ± 29 to 104 ± 28 g/m(2) with the Epic Supra valves (P < .0001 for both comparisons) was measured by TTE. Cardiac MRI revealed decreases in LVMI from 84 ± 20 to 64 ± 12 g/m(2) and from 86 ± 27 to 64 ± 17 g/m(2) with the Epic and Epic Supra valves, respectively (P < .0001 for both comparisons). TTE revealed a significant regression of mean pressure gradients from 51.6 ± 15.3 to 15.5 ± 5.2 mm Hg with the Epic and from 46.7 ± 19.4 to 17.9 ± 12.8 mm Hg with the Epic supra (P < .0001 for both comparisons).

CONCLUSIONS

A significant decrease in LVMI was measured after AVR with all sizes of both bioprosthetic models. Because of the overestimation of the decrease in LVMI by the Devereux formula, as well as the higher accuracy and reproducibility of cardiac MRI measurements, the latter should be preferred to TTE. An ultimate validation of this thesis could only be done comparing each of these modalities with pathologic examination.

Left ventricular mass regression one year after transcatheter aortic valve implantation

BACKGROUND

Left ventricular (LV) hypertrophy is associated with LV diastolic dysfunction and constitutes a risk factor for cardiac morbidity and mortality. The objective of this study was to investigate the degree of LV mass regression and the changes of LV diastolic function one year after transcatheter aortic valve implantation (TAVI).

METHODS

Echocardiography was performed at baseline, before discharge, and at one-year follow-up in 63 consecutive patients with severe aortic stenosis who underwent TAVI with the Medtronic CoreValve System (Medtronic Inc, Minneapolis, MN). The LV mass was calculated using the Devereux formula and indexed to body surface area.

RESULTS

One-year all-cause mortality was 29%. The LV mass index decreased from 126 ± 42 g/m(2) at baseline to 110 ± 30 g/m(2) at one-year follow-up (p < 0.001). Left ventricular ejection fraction and LV diastolic function did not change significantly. Mean transaortic gradient decreased from 47 ± 19 mm Hg at baseline to 9 ± 5 mm Hg at discharge and 9 ± 4 mm Hg at one year (p < 0.001), and was accompanied by significant clinical improvement. More than mild paravalvular aortic regurgitation was found in 24% and 15% of patients at discharge and one-year follow-up, respectively.

CONCLUSIONS

A significant regression in LV mass was found one year after TAVI. However, regression was incomplete and was not accompanied by an improvement in LV diastolic function.

Left ventricular mass regression after porcine versus bovine aortic valve replacement: a randomized comparison

BACKGROUND

It is unclear whether small differences in transprosthetic gradient between porcine and bovine biologic aortic valves translate into improved regression of left ventricular (LV) hypertrophy after aortic valve replacement. We investigated transprosthetic gradient, aortic valve orifice area, and LV mass in patients randomized to aortic valve replacement with either the Medtronic Mosaic (MM) porcine or an Edwards Perimount (EP) bovine pericardial bioprosthesis.

METHODS

One hundred fifty-two patients with aortic valve disease were randomly assigned to receive either the MM (n = 76) or an EP prosthesis. There were 89 men (59%), and the mean age was 76 years. Echocardiograms from preoperative, postoperative, predismissal, and 1-year time points were analyzed.

RESULTS

Baseline characteristics and preoperative echocardiograms were similar between the two groups. The median implant size was 23 mm for both. There were no early deaths, and 10 patients (7%) died after dismissal. One hundred seven of 137 patients (78%) had a 1-year echocardiogram, and none required aortic valve reoperation. The mean aortic valve gradient at dismissal was 19.4 mm Hg (MM) versus13.5 mm Hg (EP; p < 0.0001), and at 1 year was 20.4 mm Hg versus 13.4 mm Hg (p < 0.0001). These differences were similar when the analysis was stratified by surgically measured annular size. The mean change in aortic valve gradient between predismissal and 1-year echocardiogram was +2.2 mm Hg (p = 0.02) for MM and -0.8 mm Hg (p = 0.33) for EP patients (p = 0.01 MM versus EP). The mean indexed aortic valve orifice area for MM and EP groups at dismissal and at 1 year was 0.9 cm(2)/m(2) versus 1.1 cm(2)/m(2), respectively (p < 0.01; p < 0.0001). During the first year after implantation, both groups demonstrated similar regression of LV mass index (MM, -32.4 g/m(2) versus EP, -27.0 g/m(2); p = 0.40). Greater preoperative LV mass index was the sole independent predictor of greater LV mass regression after surgery (p < 0.01).

CONCLUSIONS

Small differences in transprosthetic gradient and indexed aortic valve orifice area exist between porcine and bovine aortic valves. Despite this, both prostheses allow similar regression of LV mass during the first year after aortic valve replacement.