Impact of size mismatch and left ventricular function on performance of the St. Jude disc valve after aortic valve replacement

Mechanical Hemolysis Complicating Transcatheter Interventions for Valvular Heart Disease: JACC State-of-the-Art Review

Mechanical intravascular hemolysis is frequently observed following procedures on heart valves and uncommonly observed in native valvular disease. In most cases, its severity is mild. Nevertheless, it can be clinically significant and even life threatening, requiring multiple blood transfusions and renal replacement therapy. This paper reviews the current knowledge on mechanical intravascular hemolysis in valvular disease, before and after correction, focusing on pathophysiology, approach to diagnosis, and impact of other hematological conditions on the resultant anemia. The importance of a multidisciplinary management is underscored. Laboratory data are provided about subclinical hemolysis that is commonly observed following the implantation of surgical and transcatheter valve prostheses and devices. Finally, clinical scenarios are reviewed and current medical and surgical treatments are discussed, including alternative options for inoperable patients.

Frequency and Significance of Intravascular Hemolysis Before and After Transcatheter Aortic Valve Implantation in Patients With Severe Aortic Stenosis

Intravascular hemolysis (IVH) has been identified in patients with surgical prosthetic valves, but few have been reported after transcatheter aortic valve implantation (TAVI). We conducted a prospective analysis of 64 TAVI patients. The hemolysis profiles were collected at baseline and 6 months after TAVI. The echocardiography was performed at baseline and 6 months after TAVI. There are 14 patients (21.9%) with IVH before and 24(37.5%) after TAVI. The serum haptoglobin values before and 6 months after TAVI are 126.7 ± 75.1 vs 86.3 ± 57.1 mg/dl (p < 0.001). More ≥moderate paravalvular leakage (PVL) (50% vs 7.5%, p < 0.001), bicuspid aortic valve (BAV) (33.3% vs 5.0%, p = 0.004), use of 23 mm prosthesis (29.2% vs 7.5%, p = 0.03), higher residual valvular pressure gradient (17.9 ± 6.8 mm Hg vs 14.7 ± 5.7 mm Hg, p = 0.05), and lower effective orifice area index (1.05 ± 0.21 vs 1.21 ± 0.29, p = 0.03) were observed in patients with post-TAVI IVH. On multivariate regression analysis, BAV and ≥moderate PVL are independently related to post-TAVI IVH. With log-rank test, 1-year rates of readmission due to cardiovascular cause were significantly higher in patients with post-TAVI IVH (odds ratio 4.5; 95% confidence interval 1.3 to 15.6; p = 0.02), after adjusting age and gender. In conclusion, ≥moderate PVL and BAV are predictors of post-TAVI IVH, which is associated with increased cardiovascular readmission in 1-year follow-up.

Evaluation of Intravascular Hemolysis With Erythrocyte Creatine in Patients With Aortic Stenosis

Chronic intravascular hemolysis has been identified in patients with cardiac valve prostheses, but only a few case reports have evaluated intravascular hemolysis in patients with native valvular heart disease. To detect intravascular hemolysis in patients with aortic stenosis, erythrocyte creatine was evaluated with hemodynamic indices obtained by echocardiography.Erythrocyte creatine, a marker of erythrocyte age, was assayed in 30 patients with aortic stenosis and 10 aged matched healthy volunteers. Peak flow velocity of the aortic valve was determined by continuous-wave Doppler echocardiography. Twenty of 30 patients with aortic stenosis had high erythrocyte creatine levels (> 1.8 µmol/g Hb) and erythrocyte creatine was significantly higher as compared with control subjects (1.98 ± 0.49 versus 1.52 ± 0.19 µmol/g Hb, P = 0.007). Peak transvalvular pressure gradient ranged from 46 to 142 mmHg and peak flow velocity ranged from 3.40 to 5.95 m/second. Patients with aortic stenosis had a significantly lower erythrocyte count (387 ± 40 versus 436 ± 42 × 10(4) µL, P = 0.002) and hemoglobin (119 ± 11 versus 135 ± 11 g/L, P < 0.001) as compared with control subjects. Erythrocyte creatine had a fair correlation with peak flow velocity (r = 0.55, P = 0.002).In conclusion, intravascular hemolysis due to destruction of erythrocytes was detected in patients with moderate to severe aortic stenosis and the severity of intravascular hemolysis was related to valvular flow velocity of the aortic valve.

Erythrocyte creatine as a marker of intravascular hemolysis due to left ventricular outflow tract obstruction in hypertrophic cardiomyopathy

BACKGROUND

Erythrocyte creatine, a marker of erythrocyte age that increases with shortening of erythrocyte survival, has been reported to be a quantitative and reliable marker for intravascular hemolysis. We hypothesized that hemolysis could also occur due to intraventricular obstruction in patients with hypertrophic cardiomyopathy (HCM). The purpose of this study was to examine the presence of subclinical hemolysis and the relation between intravascular hemolysis and intraventricular pressure gradient (IVPG).

METHODS AND RESULTS

We measured erythrocyte creatine in 92 HCM patients. Twelve patients had left ventricular outflow tract obstruction (LVOTO), 4 had midventricular obstruction (MVO), and the remaining 76 were non-obstructive. Erythrocyte creatine levels ranged from 0.92 to 4.36μmol/g hemoglobin. Higher levels of erythrocyte creatine were associated with higher IVPG (r=0.437, p<0.001). If erythrocyte creatine levels are high (≥1.8μmol/g hemoglobin), subclinical hemolysis is considered to be present. Half of LVOTO patients and no MVO patients showed high erythrocyte creatine levels. Although non-obstructive patients did not show significant intraventricular obstruction at rest, some showed high erythrocyte creatine levels. When LVOT-PG was measured during the strain phase of the Valsalva maneuver in 20 non-obstructive patients, 7 of those 20 patients showed LVOTO. In the 20 patients, there was no relation between erythrocyte creatine levels and LVOT-PG before the Valsalva maneuver (r=0.125, p=0.600), whereas there was a significant correlation between erythrocyte creatine and LVOT-PG provoked by the Valsalva maneuver (r=0.695, p=0.001).

CONCLUSIONS

There is biochemical evidence of subclinical hemolysis in patients with HCM, and this hemolysis seems to be associated with LVOTO provoked by daily physical activities.

Incidence and risk factors of hemolysis after transcatheter aortic valve implantation with a balloon-expandable valve

There are currently no data evaluating the hematologic and biocompatibility profile of transcatheter aortic valves in vivo. We evaluated the incidence, predictive factors, and clinical consequences associated with hemolysis post-transcatheter aortic valve implantation (TAVI). A total of 122 patients who underwent TAVI with a balloon-expandable valve were included. Baseline blood sampling and echocardiography, followed by early post-TAVI echocardiography and repeat blood sampling, at 6 to 12 months post-TAVI were performed. Hemolysis post-TAVI was defined according to the established criteria. The incidence of hemolysis post-TAVI was 14.8% yet no patient experienced severe hemolytic anemia requiring transfusion. Compared with the nonhemolysis group, those with hemolysis demonstrated significant reductions in hemoglobin (p = 0.012), were more frequently women (67% vs 34%, p = 0.016), and had a higher incidence of post-TAVI severe prosthesis-patient mismatch (PPM) (44% vs 17%, p = 0.026). The rate of mild or more prosthetic valve regurgitation did not significantly differ between those patients with and without hemolysis (56% vs 37%, p = 0.44). Wall shear rate (WSR) and energy loss index (ELI), both indirect measures of shear stress, were higher (p = 0.039) and lower (p = 0.004), respectively, in those patients with hemolysis. Increasing PPM severity was also associated with significant stepwise WSR increments and ELI decrements (p <0.01 for both). In conclusion, subclinical hemolysis occurred in 15% of patients following TAVI. Although prosthetic valve regurgitation had no impact on hemolysis, a novel association between PPM and hemolysis was found, likely driven by higher shear stress as determined by WSR and ELI. These hematologic and biomechanical findings may have long-term clinical implications and could affect future transcatheter aortic valve design.

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

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

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

BACKGROUND

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

METHOD

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

RESULT

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

DISCUSSION

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

Atrial Natriuretic Peptide Predicts Impaired Atrial Remodeling and Occurrence of Late Postoperative Atrial Fibrillation after Surgery for Symptomatic Aortic Stenosis

BACKGROUND

Aortic stenosis (AS) and atrial fibrillation (AF) are commonly encountered in clinical practice. Natriuretic peptides (NP) are endogenous cardiac hormones, which have been shown to increase in patients with heart failure, and valvular or congenital heart disease. We aimed to determine the association between atrial NP (ANP) and late postoperative AF after surgery for AS along with temporal changes in plasma ANP levels and left atrial (LA) volumes.

METHODS

22 patients (16 males/6 females, mean age: 61 years) with symptomatic AS and 8 healthy volunteers (5 males/3 females) were enrolled into our study. All the patients studied underwent transthoracic echocardiography, which was repeated during the follow-up. N-terminal ANP (N-ANP) was studied initially and at the 2-month follow-up. Postoperatively, the patients were followed up for 12 months for AF attacks.

RESULTS

Patients with AS had significantly higher levels of N-ANP, left ventricular (LV) end-diastolic pressure, E/A ratio, LV mass and LA volumes compared to the controls. Patients with postoperative AF attacks were significantly older, had higher N-ANP levels and LV end-diastolic pressure in addition to higher LA volumes and longer symptom duration compared to patients without AF. Age at the time of operation (p = 0.011) and N-ANP at the 2nd month (p = 0.047) were found to be independent predictors for late AF attacks during follow-up in regression analysis. Besides, N-ANP (p < 0.001) at the 2-month follow-up independently predicted impaired LA remodeling.

CONCLUSION

ANP might be an important factor to identify AS patients at risk for late postoperative AF attacks.

Hemodynamic function of the standard St. Jude bileaflet disc valve has no clinical impact 10 years after aortic valve replacement

OBJECTIVES

Size mismatch and impaired left ventricular function have been shown to determine the hemodynamic function of the standard St. Jude bileaflet disc valve early after aortic valve replacement (AVR). We aimed to analyse St. Jude valve hemodynamic function and its clinical impact in the survivors of a prospective series 10 years after AVR for aortic stenosis.

DESIGN

Forty-three survivors aged 32-90 years from a prospective series attended a follow-up study with Doppler echo and radionuclide cardiography 10 years after AVR for aortic stenosis. Six patients with significant left sided valve regurgitation were excluded from further analysis: they had significantly lower St. Jude valve gradient and left ventricular ejection fraction (LVEF) and larger mass index (LVMi) than 37 without.

RESULTS

In the 37 patients without left sided valve regurgitation peak and mean gradients were inversely related to St. Jude valve geometric orifice area (GOA) indexed for either body surface area or left ventricular end-diastolic dimension (LVEDD). The gradients correlated directly with LVEDD but not with LVEF or LVMi. Eleven patients with hypertension had higher peak gradients (31+/-13 versus 22+/-8 mmHg, p<0.05), lower LVEF, and higher LVEDD and LVMi than 26 without. Peak gradient was greater than 35 mmHg in five hypertensive patients with normal LVEF but lesser than 30 mmHg in six with impaired LVEF. Supranormal LVEF and severe size mismatch identified the remaining patients (N=3) with peak gradient above 35 mmHg. In a multilinear regression analysis GOA indexed for LVEDD, hypertension, and LVEF were independently related to peak gradient.

CONCLUSION

High gradients of the standard St. Jude bileaflet disc valve 10 years after AVR was primarily related to systemic hypertension and mismatch between valve and left ventricular cavity size. Hypertension and left sided valve regurgitation, but not St. Jude valve gradient or size mismatch, were the dominant determinants of left ventricular hypertrophy and impaired function.

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.

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.

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.

Evaluation of Intravascular Hemolysis With Erythrocyte Creatine in Patients With Cardiac Valve Prostheses

STUDY OBJECTIVES

To detect intravascular hemolysis in patients with cardiac valve prostheses. Erythrocyte creatine, a marker of erythrocyte age that increases with shortening erythrocyte survival, was evaluated with other hemolytic markers and hemodynamic parameters.

DESIGN

Prospective study.

PATIENTS AND MEASUREMENTS

Erythrocyte creatine was enzymatically assayed in 33 patients with prosthetic valves, including 15 patients with aortic valve replacement, 13 patients with mitral valve replacement, and 5 patients with double-valve (aortic and mitral) replacement, and 33 control subjects. Blood flow velocity and valvular regurgitation were determined by Doppler echocardiography. Other hemolytic markers (lactate dehydrogenase [LDH], reticulocyte count, and haptoglobin) and cardiac muscle markers (myoglobin and myosin light chain 1) were also measured.

RESULTS

Erythrocyte creatine and LDH levels were significantly higher (p < 0.0001) and the haptoglobin level was lower (p < 0.0001) in patients with a prosthetic valve as compared with control subjects. However, there were no significant differences in these markers between those with (n = 17) and without (n = 16) regurgitation. Patients with high erythrocyte creatine levels (> 1.8 micro mol/g hemoglobin) exhibited significantly higher total peak flow velocity (sum of peak flow velocities at mitral and aortic valves) than those with normal erythrocyte creatine levels (p = 0.006). Erythrocyte creatine had a significant correlation with total peak flow velocity (r = 0.64, p < 0.0001), but LDH and haptoglobin had no significant correlation with total peak flow velocity. Patients with high LDH levels (> 460 IU/L) showed significantly higher myoglobin (p = 0.008) and myosin light chain 1 (p = 0.02) than those with normal LDH levels, whereas erythrocyte creatine was not related to cardiac muscle markers.

CONCLUSIONS

Erythrocyte creatine is a quantitative and reliable marker for intravascular hemolysis in patients with prosthetic valves. Mild hemolysis is ascribable to valvular flow velocity rather than regurgitation.

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.

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.

Changes in left and right ventricular cardiac function after valve replacement for aortic stenosis determined by cine MR imaging

The purpose of this study was to determine the changes in function of both the left and the right ventricles (LV, RV) before and after aortic valve replacement (AVR), compared with age-matched healthy volunteers using magnetic resonance (MR) imaging. Fourteen patients with aortic stenosis underwent MR imaging (1.5 T) before and 3 (n = 14) and 12 (n = 9) months after surgical valve replacement. An electrocardiographically triggered two-dimensional cine fast low-angle shot sequence was used for the evaluation of absolute values and indices related to 1 m(2) body surface area for function, mass, and LV wall thickening. Fourteen age-matched healthy volunteers served as controls. Before surgery, all patients showed significant abnormalities of LV mass and function, whereas RV mass and function were not different from those of volunteers and remained mostly unchanged. After surgery, normalization of LV ejection fraction, absolute mass, and end-systolic wall thickness was observed, whereas the LV mass index failed to normalize, and LV volumes remained elevated. Aortic stenosis combined with a significant, but not severe reduction in LV function only affects the LV, whereas the RV remains unaffected at this stage of disease. AVR leads to improved LV function and reduced hypertrophy, but without normalization of LV volumes or the LV mass index within 1 year.

Standard aortic St. Jude valve at 18 years: performance profile and determinants of outcome

BACKGROUND

The standard St. Jude disc valve has been in use for 20 years and remains the dominant mechanical valve of today. With nearly 19 years of follow-up, the present large series could indicate the performance profile and its determinants in the very long term.

METHODS

A detailed follow-up was performed to a maximum of 18.6 years in 694 patients aged 15 to 83 years who undervent aortic valve replacement (AVR) with the standard St. Jude valve during 1980 to 1993. The Cox regression analysis was used to identify independent determinants of outcome in the aortic stenosis (n = 490) and regurgitation (n = 204) groups.

RESULTS

Overall survival was 58%, 39%, and 37% at 10, 15, and 18 years, respectively. Only 12% of deaths (0.60%/ patient-year) were related to the valve with a 15-year freedom of 91%. Embolism (1.18%/patient-year) and anticoagulant-related bleeding (2.24%/patient-year) were the dominant complications with 10-year/15-year freedoms of 90%/80% and 85%/72%, respectively. Only 24% of bleeding events were classified as major. Valve thrombosis occurred in 2 patients (0.04%/patient-year): 1 did not receive vitamin K antagonist treatment and International Normalized Ratio was below target level in the other. There were no mechanical failures. Endocarditis (0.42%/patient-year) and paravalvular leak (0.42%/ patient-year) occurred with 15-year freedoms of 92% and 96%, respectively, with a relation between the latter (but not the former) and preoperative endocarditis in the regurgitation group. Freedom from serious complications (2.33%/patient-year) and all complications joined (4.33%/ patient-year) were 72% and 54%, respectively, at 15 years with a 96% freedom from redo AVR (0.36%/patient-year). Age- and heart-related variables were independent risk factors for mortality, thromboembolism, bleeding, serious complications, and all complications joined. Small valve (19 and 21 mm) adversely affected serious and all complications in the regurgitation group.

CONCLUSIONS

With a follow-up approaching 2 decades and exhibiting a low rate of valve-related deaths, acceptable low thrombogenicity, and absence of mechanical failure, the standard aortic St. Jude disc valve sets the standard for contemporary mechanical valves.

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.

Primary aortic valve replacement with allografts over twenty-five years: valve-related and procedure-related determinants of outcome

OBJECTIVES

Allografts offer many advantages over prosthetic valves, but allograft durability varies considerably.

METHODS

From 1969 through 1993, 618 patients aged 15 to 84 years underwent their first aortic valve replacement with an aortic allograft. Concomitant surgery included aortic root tailoring (n = 58), replacement or tailoring of the ascending aorta (n = 56), and coronary artery bypass grafting (n = 87). Allograft implantation was done by means of a "freehand" subcoronary technique (n = 551) or total root replacement (n = 67). The allografts were antibiotic sterilized (n = 479), cryopreserved (n = 12), or viable (unprocessed, harvested from brain-dead multiorgan donors or heart transplant recipients, n = 127). Maximum follow-up was 27.1 years.

RESULTS

Thirty-day mortality was 5.0%, and crude survival was 67% and 35% at 10 and 20 years. Ten- and 20-year rates of freedom from complications were as follows: endocarditis, 93% and 89%; primary tissue failure, 62% and 18%; and redo aortic valve replacement, 81% and 35%. Multivariable Cox analyses identified several valve- and procedure-related determinants: rising allograft donor age and antibiotic-sterilized allograft for mortality; donor more than 10 years older than patient for endocarditis; rising donor age minus patient age, rising implantation time (from harvest to aortic valve replacement), and donor age more than 65 years for tissue failure; and rising donor age minus patient age, young patient age, rising implantation time, and subcoronary implantation preceded by aortic root tailoring for redo aortic valve replacement. Estimated 10- and 20-year rates of freedom from tissue failure for a 70-year-old patient with a viable valve from a 30-year-old donor and no other risk factors were 91% and 64%; the figures were 71% and 20% if the donor age was 65 years. The rates of freedom from tissue failure for a 30-year-old patient with a 30-year-old donor were 82% and 39%; the figures were 49% and 3% with a 65-year-old donor. Beneficial influences of a viable valve were largely covered by short harvest time (no delay for allografts from brain dead organ donors or heart transplant recipients) and short implantation time.

CONCLUSIONS

Primary allograft aortic valve replacement can give acceptable results for up to 25 years. The late results can be improved by the use of a viable allograft, by matching patient and donor age, and by more liberal use of free root replacement with re-implantation of the coronary arteries rather than tailoring the root to accommodate a subcoronary implantation.

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.