Exercise echocardiographic comparison of pulmonary autograft and aortic homograft replacements for aortic valve disease in adults

BACKGROUND AND AIM OF THE STUDY: The pulmonary autograft, or Ross procedure, has theoretical hemodynamic benefits over other aortic valve replacements. The hemodynamic performance of the pulmonary autograft and pulmonary homograft components of this procedure have not been well defined. METHODS: Twenty patients with pulmonary autograft replacement of the aortic valve and six with aortic homografts underwent exercise echocardiography with assessment of exercise duration, left ventricular dimensions, mass, and function. Hemodynamics at rest and maximal exercise, including Doppler gradients and effective orifice area (EOA), were measured across the pulmonary autograft and aortic homograft valves. Doppler gradients across the pulmonary homograft valves were compared to native pulmonary valve gradients at rest and maximal exercise. RESULTS: Both groups of patients had excellent self-reported and measured exercise capacity. In comparison to the aortic homograft, the pulmonary autograft had lower peak Doppler gradients across the neoaortic valve at rest (5 +/- 2 versus 11 +/- 4 mmHg; p = 0.027) and maximal exercise (10 +/- 5 versus 15 +/- 5 mmHg; p = 0.003) and larger indexed EOA. However, the Ross procedure patients had higher gradients across the pulmonary homograft both at rest (14 +/- 10 versus 3 +/- 1 mmHg; p < 0.001) and maximal exercise (25 +/- 22 versus 5 +/- 4 mmHg; p = 0.004). Two patients in the Ross procedure group had significant pulmonary homograft stenosis in short- or mid-term follow up. CONCLUSION: In comparison to aortic homograft replacement of the aortic valve, pulmonary autograft replacement has superior hemodynamics at rest and during exercise. However, the pulmonary homograft replacement may develop hemodynamically significant stenosis after the Ross procedure.     

Transvalvular velocities after full aortic root replacement: results from a prospective randomized trial between the homograft and the Medtronic Freestyle bioprosthesis

BACKGROUND AND AIM OF THE STUDY: Unstented bioprostheses offer better hemodynamics after aortic valve replacement. It has been reported recently that subcoronary implantation of the Freestyle valve may result in increased transvalvular velocities. In a prospective randomized trial, transvalvular velocities were investigated after implantation of a homograft or a Medtronic Freestyle bioprosthesis as a full root. METHODS: A total of 137 patients was randomized to receive either a homograft (group H, n = 64) or a Freestyle (group F, n = 73) root replacement. Echocardiographic investigations were performed at six weeks, six months, and then yearly after surgery. Transvalvular and subvalvular velocities were recorded from each echocardiogram. RESULTS: At follow up, none of the patients showed high transvalvular or subvalvular velocities (>2 m/s). At six weeks after surgery the transvalvular velocity was 1.5+/-0.3 m/s in group H (n = 51) and 1.7+/-0.3 m/s in group F (n = 56) (p = NS), while subvalvular velocities were 0.9+/-0.3 and 1.0+/-0.3 m/s, respectively (p = NS). These findings remained constant up to the three-year follow up, when transvalvular velocity was 1.6+/-0.4 m/s in group H (n = 10) and 1.6+/-0.2 m/s in group F (n = 15) (p = NS). Subvalvular velocities were 0.9+/-0.1 and 0.9+/-0.1 m/s, respectively (p = NS). CONCLUSION: Full aortic root replacement and reimplantation of the coronary arteries either with the Medtronic Freestyle or the homograft valve produces near-normal transvalvular velocities less than were reported for the Freestyle in the subcoronary implantation.     

Exercise hemodynamic performance of the pulmonary autograft following the Ross procedure.

BACKGROUND AND AIMS OF THE STUDY: The Ross procedure, in which the aortic valve is replaced with the patient's own pulmonary valve (pulmonary autograft), is considered an excellent alternative for younger patients requiring elective aortic valve replacement. Although resting pulmonary autograft hemodynamics are excellent, exercise hemodynamic data are lacking. The study aim was to measure the hemodynamic performance of the pulmonary autograft with exercise Doppler echocardiography (DE). METHODS: Twenty-four Ross procedure patients (20 males, four females; mean age 46 +/- 11 years) were studied at 25 +/- 14 months after aortic valve replacement with a pulmonary autograft. Patients had baseline supine DE to measure the maximum velocity (Vmax), and the peak and mean pressure gradient across the pulmonary autograft. Effective orifice area was calculated from the continuity equation and indexed to body surface area (EOAi). Patients then underwent symptom-limited upright bicycle exercise with supine DE repeated immediately on stopping exercise. For comparison, 10 normal controls (age 41 +/-10 years) and five mechanical aortic valve patients (mean age 55 +/- 10 years) were studied. RESULTS: At rest: Ross procedure patients had similar Vmax (1.2 +/- 0.2 m/s), peak gradient (6 +/- 2 mmHg), mean gradient (4 +/- 1 mmHg) and EOAi (1.7 +/- 0.4 cm2/m2) to those of normal controls. Mechanical-valve patients had significantly higher Vmax (2.5 +/- 0.2 m/s, p <0.001), peak gradient (25 +/- 4 mmHg, p <0.001) and mean gradient (14 +/- 3 mmHg, p <0.001) than Ross patients and normal controls. At exercise: Ross procedure patients had similar Vmax (1.8 +/- 0.4 m/s versus 2.1 +/- 0.2, p = NS), peak gradient (14 +/- 6 mmHg versus 17 +/- 4, p = NS) and mean gradient (8 +/- 4 mmHg versus 10 +/- 2, p = NS) to normal controls, with no significant change in EOAi. Mechanical-valve patients had significantly higher Vmax (3.4 +/- 0.3, p <0.001), peak gradient (48 +/- 7 mmHg, p <0.001) and mean gradient (30 +/- 5 mmHg, p <0.001) than Ross patients and normal controls. CONCLUSIONS: Aortic valve replacement using the Ross procedure provides excellent hemodynamic results at rest and on exercise, with DE parameters indistinguishable from those of normal controls. This study provides further support for the use of the Ross procedure as a preferred method of aortic valve replacement in younger patients.     

Ross operation in children: late results.

BACKGROUND AND AIM OF THE STUDY: Although the Ross operation has become the accepted aortic valve replacement in children, the long-term fate of the pulmonary autograft valve remains unknown. To assess mid-term and late results of autograft valve durability, patient survival and valve-related morbidity, a retrospective review of patients (age range: 3 days to 17 years) having a Ross operation between November 1986 and May 2001 were reviewed. METHODS: Medical records and patient contacts with all but two of 167 current survivors of 178 consecutive patients having an aortic valve replacement as a Ross operation have been completed during the past two years. The most recent echocardiographic evaluation was reviewed for autograft valve and homograft valve function. RESULTS: Operative mortality was 4.5% (8/178), with three late deaths (two were non-valve-related) for an actuarial survival of 92+/-3% at 12 years. Actuarial freedom from autograft valve degeneration (reoperation or severe insufficiency of autograft valve or valve-related death) was 90+/-4% at 12 years. Autograft valve degeneration was not affected by technique of insertion (141 root replacement, 37 intra-aortic), aortic valve morphology (157 bicuspid or unicuspid, 26 tricuspid), or age at operation. Autograft valve degeneration was worse in patients with a primary lesion of aortic insufficiency than in those with aortic stenosis (p = 0.03). Autograft valve reoperation was required in 12 patients, with autograft valve replacement in seven. Actuarial freedom from autograft replacement was 93+/-3% at 12 years. Homograft valve replacement was required in seven patients, with actuarial freedom from replacement of 90+/-4% at 12 years. Eight additional patients have homograft valve obstruction (gradient > or =50 mmHg), and seven have severe pulmonary insufficiency. CONCLUSION: Survival and freedom from aortic valve replacement are excellent in children. Homograft valve late function remains a concern, and efforts to improve homograft durability should be encouraged.     

Aortic valve replacement with pulmonary autograft (the Ross procedure) in adult and pediatric patients

Aortic valve replacement with pulmonary autograft was first performed by Donald Ross in 1967. Initially, the procedure was not widely accepted, by Cardiologists and Cardiac surgeons fundamentally due to its complexity and demanding surgical technique, and because innumerous series two cardiac valves were at risk. The results published in the last 10-15 years established the pulmonary autograft as one of the best methods of aortic valve replacement, especially in pediatric patients and young adults. In the present article, we reviewed present indications and contraindications, and our clinical experience with 26 patients (pediatrics and adults). Analysis of the first 22 the patients with a minimum of 6 months of follow-up (180-620 days) was performed. Follow-up is complete (100%). Mean age was 31.4 +/- 12.6 years. Five patients were pediatrics (<= 14 years). Three patients (11%) with previous percutaneous procedures and 4 patients (14%) with previous surgical procedures. There was no early or late mortality. In the last follow-up, 19 of 22 (86.36%) had no autograft insufficiency (>= grade 1), and in one patient it was moderate (grade 2). The 2 remaining patients developed severe autograft insufficiency (grade 4) and were reoperated on, with satisfactory postoperative outcome. Mean maximal gradient was 7.85 +/- 5 mmHg at 18 months (3-29). Patients with preoperative aortic stenosis showed a significant reduction in myocardial mass index (208.7 +/- 32 a 95.8 +/- 28.8 g/m2) at 18 months. In these patients, septal and posterior wall thickness decreased significantly, in the first month. Two pediatric patients have developed transpulmonar gradient > 50 mmHg. One of them underwent successful stent implantation. We have not observed significant homograft insufficiency in any of our patients. All our patients remain asymptomatic (functional class I) without medical treatment. We have not observed either thromboembolic or haemorrhagic episodes, nor endocarditis. No patient is receiving anticoagulants. Clinical and echocardiographic mid term results in pulmonary autograft and homograft in our series, are excellent after the Ross procedure.     

Echocardiographic follow-up after Ross procedure in 100 patients

The Ross procedure could provide an ideal aortic valve replacement method in children and young adults. We evaluated midterm echocardiographic results to assess pulmonary homograft function as well as pulmonary autograft dimensions and function. In all, 105 patients (26 women and 79 men) underwent the Ross procedure; median age at implant was 29 years. All patients underwent free root replacement. Transvalvular gradients and autograft dimensions were measured at 3 levels (annulus, sinuses of Valsalva, and proximal aorta) at discharge, at 6 months, and annually thereafter. Perioperative mortality was 4.7%. The mean period for echocardiographic follow-up in 100 patients was 32.7 months (range 0.5 to 7 years), during which 4 noncardiac-related deaths occurred. Two patients underwent late reintervention. No moderate or severe regurgitation was recorded. There was 1 case of mild homograft regurgitation and 4 of mild autograft regurgitation at late follow-up. Autograft peak gradients were low and reproducible (5 +/- 2.8 mm Hg at discharge vs 5.5 +/- 3.5 mm Hg at last follow-up, p = NS). Homograft peak gradients increased significantly without severe obstruction (7.8 +/- 5.7 mm Hg at discharge vs 15.8 +/- 9.2 mm Hg at last follow-up). The diameter of the autograft annulus was stable during follow-up, whereas autograft dimensions at sinuses and proximal aorta increased significantly. One group of patients was identified with sinus diameter increases >20% (group A). The 90 remaining patients were classified into group B. The only parameter significantly different between the 2 groups was the sinus diameters measured at discharge (1.74 cm/m2 (group A) vs 1.92 cm/m2 (group B); p = 0.036). In 100 patients and with echocardiographic follow-up for up to 7 years, the Ross procedure showed excellent results. For 10% of patients, we observed a 20% dilation of sinus diameters, but in only 3 patients (3%) was this beyond the upper normal limit.     

Hemodynamic performance during maximum exercise in adult patients with the ross operation and comparison with normal controls and patients with aortic bioprostheses

This study examines the resting and exercise hemodynamic performance of the pulmonary autografts in the aortic position as well as of the homografts used for right ventricular outflow reconstruction in patients undergoing the Ross operation. Previous studies have reported excellent resting hemodynamics in patients who underwent aortic valve replacement with a pulmonary autograft. However, there are very few studies of their hemodynamic performance during exercise. Twenty adult subjects who underwent the Ross operation and 12 normal control subjects were submitted to maximum romp bicycle exercise. The valve effective orifice areas and transvalvular gradients of both aortic (autograft) and pulmonary (homograft) valves were measured at rest and at peak of maximum exercise using Doppler echocardiography. Valve areas were indexed for body surface area. The hemodynamics of the aortic valve were very similar in Ross subjects and in control subjects at rest and during exercise. However, the indexed valve area of the pulmonary valve at rest was significantly (p < 0.001) lower in the Ross subjects (1.10 +/- 0.46 cm2/ m2) than in the control subjects (1.95 +/- 0.41 cm2/m2), resulting in higher (p = 0.004) mean gradients at rest (Ross: 9 +/- 7 mm Hg vs control: 2 +/- 1 mm Hg) and at peak exercise (Ross: 21 +/- 14 mm Hg vs control: 7 +/- 2 mm Hg). The pulmonary autograft provided excellent hemodynamics in the aortic position either at rest or during maximum exercise, whereas moderately high gradients were found during exercise across the homograft implanted in the pulmonary valve position. Future improvement of the Ross procedure should be oriented toward the search of new methods to prevent the deterioration of the homografts.     

The ross procedure for replacement of the bicuspid aortic valve: mid-term results from 55 consecutive cases

BACKGROUND AND AIM OF THE STUDY: A congenitally dysfunctioning bicuspid aortic valve may require surgical treatment in children and young adults. This retrospective study evaluated mid-term clinical results obtained with the Ross procedure in this patient group. METHODS: Between July 1994 and December 2000, 55 patients (48 males, seven females; mean age 27+/-10 years; range: 7-49 years) underwent replacement of a diseased bicuspid aortic valve (stenosis in six cases (11%); insufficiency in 36 (65%); mixed lesion in 13 (24%)) with a pulmonary autograft. Mean NYHA functional class was 1.7. Five patients (9%) had healed endocarditis and six (11%) had previous cardiac surgery. The autograft was inserted as a subcoronary implant in two cases (4%), as a root in 40 (73%), and as a cylinder in 13 (23%). The right ventricular outflow tract was reconstructed with a cryopreserved pulmonary homograft in all cases. Mean cardiopulmonary bypass and aortic cross-clamp times were 207+/-34 min and 162+/-18 min, respectively. RESULTS: No early or late deaths had occurred at a mean follow up of 31+/-19 months. Two patients (4%) were re-explored for bleeding. Four patients (7%) experienced intraoperative coronary complications which resolved without sequelae. Two-dimensional echocardiographic evaluation of neoaortic valve competence at six months revealed no evidence of aortic valve regurgitation in 46 patients (84%), trivial regurgitation in seven (13%), mild regurgitation in one patient (2%), and moderate regurgitation in one patient. The latter patient (subcoronary implant) required reoperation. At six months, the degree of regression of left ventricular mass compared (versus preoperative) was 34+/-13% (p <0.05). Three patients (5%) showed mild dilatation (>4 cm) of the neoaortic root after two years follow up. All patients are currently asymptomatic, in NYHA class I, and enjoy a normal social lifestyle. CONCLUSION: The Ross procedure may be offered as a low-risk alternative in adolescents and young adults with a bicuspid aortic valve. Although the inclusion cylinder technique might help to prevent root dilatation, continued patient evaluation with regard to root sizing, evidence of neoaortic valve degeneration and homograft dysfunction is required in the long term.     

Ten years' experience in aortic valve replacement with homografts in 389 cases

BACKGROUND AND AIM OF THE STUDY: Aortic valve replacement using homografts is an accepted alternative to the use of other replacement devices, and has been established at the authors' institution for more than 10 years. METHODS: Since 1992, a total of 389 homografts was implanted, and 332 patients (mean age 54 years, 72% males) were followed up. The initial patients (n = 75) had subcoronary implantation, all subsequent patients had root replacement. Both aortic grafts (AG) and pulmonary grafts (PG) were used. Follow up was conducted with regard to the factors 'graft origin', 'implantation technique' and 'gender', and included clinical examination, ECG and transthoracic echocardiography on an annual basis. RESULTS: Overall 30-day mortality was 5.4% (AG patients 3.9%, PG patients 13.5%; p = 0.09). Among late deaths (n = 22), six were valve-related (all prosthetic infection). Four minor thrombembolic events were recorded due to amaurosis fugax and transient ischemic attacks (TIA). Freedom from reoperation was 86.5%. Indication for graft replacement was greater after subcoronary implantation than after root implantation (p = 0.04). Reoperation was necessary in 24 patients due to restenosis (n = 4), regurgitation grade >II (n = 5), paravalvular leak (n = 2) and prosthetic infection (n = 13). At the latest echocardiographic follow up, mean peak pressure gradient was 15.60 +/- 11.76 mmHg, homograft regurgitation grade was 0.82 +/- 0.66, left ventricular end-diastolic diameter (EDD) was 49.1 +/- 7.54 mm, and mean aortic root diameter was 30.54 +/- 5.48 mm. When comparing parameters at a mean of five years postoperatively, the pressure gradient increased from 10.26 to 15.02 mmHg, regurgitation grade increased from 0.53 to 0.81, and EDD decreased from 52.3 to 50.4 mm. Other variables showed no significant differences. CONCLUSION: The present results confirmed good midterm-results for aortic valve replacement with homografts. These prostheses are vulnerable to infection, and root replacement was superior to the subcoronary implantation technique.     

The ross operation in 225 patients: a five-year experience in aortic root replacement.

BACKGROUND AND AIM OF THE STUDY: The Ross operation, introduced more than 30 years ago, has recently undergone several modifications to improve both technical feasibility and results. At the authors' institution, the Ross operation, performed as root replacement in all cases, was commenced in February 1995. METHODS: A total of 225 patients (177 males, 48 females; mean age 39+/-15 years; range: 2 to 67 years) were operated on up to December 2000. Aortic regurgitation was present in 80 patients, stenosis in 69, and combined disease in 73; prostheses were replaced in three patients. Combined procedures were performed in 51 patients. Nine patients had active endocarditis. Follow up was 98% complete and totaled 471 patient-years. RESULTS: There was no early mortality, and no thromboembolic or hemorrhagic events. Complications included prolonged ventilation in two patients, perioperative myocardial infarction in three, pacemaker implants in three and perioperative bleeding in six. One patient died at 25 months from hemoptysis, and one at five months of unknown cause. In the long term, four patients required reoperation due to autograft regurgitation (one autograft repair, three autograft replacements). Routine aortic annulus support, a lowered threshold in replacing all dilated ascending aorta and keeping the autograft short to the level of the sinotubular junction seems to have prevented further autograft failure. Pulmonary homograft stenosis led to reoperation in one patient. Six patients with elevated gradients are currently under observation. Echocardiography revealed autograft median peak gradients of 5.1+/-2.8 mmHg, pulmonary homograft gradients of 14.2+/-11.5 mmHg, and no significant regurgitation, except in one additional patient with recently diagnosed aortic insufficiency (grade >2). CONCLUSION: Mid-term excellent hemodynamic results, low morbidity and reoperation requirement support the evolved root replacement technique and justify its further utilization.     

Hemodynamics of semilunar valves at rest and exercise at an average of more than two years after the Ross procedure

BACKGROUND AND AIM OF THE STUDY: Rest, and especially exercise, hemodynamics are valuable determinants to assess outcome of the Ross procedure. In this study, the degree of insufficiency and pressure gradients at rest across the autograft and homograft, as well as the pressure gradients at exercise, were measured. METHODS: Among 115 patients operated on between February 1990 and February 1999, 67 were evaluated echocardiographically at rest and moderate exercise. The mean patient age at subcoronary implantation was 52 +/- 13 years. The mean interval between surgery and investigation was 27.3 +/- 17.4 months. The exercise level was 100 W (n = 47), 75 W (n = 14) or 50 W (n = 6). RESULTS: Fifty-two patients had no or trace aortic insufficiency, 23 were grade I/IV, and two were grade II/IV. Pulmonary insufficiency was graded as none (n = 45), mild (n = 21), and moderate (n = 1). Heart rate increased from 70 +/- 12 beats/min at rest to 108 +/- 19 beats/min at exercise. The maximal pressure gradient across the autograft increased from 6.1 +/- 2.3 mmHg at rest to 8.7 +/- 4.1 mmHg at exercise. The maximal pressure gradient across the homograft increased from 11.8 +/- 5.3 mmHg at rest to 17.7 +/- 8.2 mmHg at exercise. A pressure gradient across the homograft >25 mmHg was measured in 13 patients. CONCLUSION: In most patients, hemodynamics at rest and moderate exercise at an average of more than two years after the Ross procedure were excellent. Some homografts developed pressure gradients at exercise; this finding will form the target of future surgical and scientific investigations.     

Stented bioprosthetic valve hemodynamics: is the supra-annular implant better than the intra-annular?

BACKGROUND AND AIM OF THE STUDY: The use of stented bioprostheses for aortic valve replacement (AVR) in elderly patients with a small aortic annulus may result in unsatisfactory hemodynamic performance of the prosthesis. To overcome this limitation, new bioprostheses have been designed for complete supra-annular implantation, but the actual hemodynamic advantage of the supra-annular implant over the intra-annular has not been fully investigated. Accordingly, the hemodynamic performance of the same stented bioprosthesis (except for sewing ring design) implanted in the supra-annular and conventional intra-annular seating was compared. METHODS: Twenty-two patients received an intra-annular implant, and 38 a supra-annular implant. Age (74 +/- 5 versus 76 +/- 5 years, p = 0.54), gender (55% versus 50% males, p = 0.79) and body surface area (1.74 +/- 0.2 versus 1.81 +/- 0.2 m2, p = 0.13) were similar in both subgroups, who underwent echocardiography at 8 +/- 2 and 6 +/- 2 months after surgery, respectively (p = 0.09). RESULTS: The two patient subgroups had similar preoperative left ventricular outflow tract diameters (2.06 +/- 0.2 and 2.1 +/- 0.2 cm; p = 0.62), average size of implanted prosthesis (21.0 and 21.3 mm; p = 0.44) and mean transprosthetic flow rate (246 +/- 70 and 218 +/- 58 ml/s; p = 0.12). Mean (8 +/- 3 and 19 +/- 8 mmHg, p < 0.0001), and peak (17 +/- 6 and 40 +/- 13 mmHg; p < 0.0001) transprosthetic gradients were lower, and mean effective orifice area (EOA) (1.78 +/- 0.4 and 1.45 +/- 0.5 cm2, p = 0.006) was higher in patients with supra-annular implants than in those with intraannular. The incidence of patient-prosthesis mismatch (EOA index < 0.85 cm2/m2) decreased from 50% to 34% (p < 0.0001), with no case of severe mismatch using the supra-annular implant. During follow up, a left ventricular mass reduction occurred in patients with supra-annular implants (from 225 +/- 110 to 173 +/- 59 g/m2; p < 0.03), but not in patients with intra-annular implants (173 +/- 62 and 186 +/- 64 g/m2; p = 0.87) CONCLUSION: The study results showed that, compared to intra-annular implantation, supra-annular implantation of bioprosthetic stented valves in the aortic position was associated with a significantly better hemodynamic performance of the prosthesis and significant regression of left ventricular hypertrophy.     

Prosthetic valve hemodynamics assessed by the left ventricular outflow tract area utilization index: a randomized study of the carbomedics reduced versus the Medtronic Hall valve

BACKGROUND AND AIM OF THE STUDY: Continuous changes are made in valve prosthesis design in order to improve hemodynamic performance. In this prospective, randomized study, hemodynamic properties of the bileaflet CarboMedics Reduced (CM-R) valve with a thinner sewing ring was compared to the Medtronic Hall (MH) disc valve. Special emphasis was placed on the ability of the two valve types to make the most effective use of the available left ventricular outflow tract (LVOT) area as defined by preoperative echocardiographic measurements. METHODS: Twenty patients scheduled for a mechanical aortic valve prosthesis were randomized to receive either a CM-R or MH valve. Only patients receiving a prosthesis < or = 25 mm were included. A complete Doppler echocardiographic study was performed preoperatively and at six months postoperatively. Transprosthetic gradients, effective orifice area (EOA), effective orifice area index (EOAI) and LVOT-utilization index (LVOT-UI; defined as EOA/preoperative LVOT area) were compared. RESULTS: The CM-R valve was superior to the MH valve for all hemodynamic parameters studied: EOA 2.03 +/- 0.50 versus 1.56 +/- 0.20 cm2 (p < 0.01); EOAI 1.07 +/- 0.22 versus 0.83 +/- 0.13 cm2/m2 (p = 0.01); and LVOT-UI 0.47 +/- 0.09 versus 0.38 +/- 0.05 (p = 0.001). Although cardiac output was significantly higher in the CM-R group, transprosthetic gradients were lower (peak 21 +/- 5 versus 27 +/- 5 mmHg (p = 0.02); mean 11 +/- 4 versus 13 +/- 2 mmHg (p = 0.07)). CONCLUSION: The results of this study showed that the CM-R aortic valve offers favorable hemodynamics compared to the MH valve. The inclusion of preoperative LVOT area measurements (as LVOT-UI) showed that the CM-R offers a more effective use of the available LVOT area.     

Reoperations for aortic aneurysm after the Ross procedure

BACKGROUND AND AIM OF THE STUDY: Among late complications after the Ross operation, autograft dilatation is likely the most common. In order to define prevalence, consequences and management of autograft dilatation, a 10-year clinical experience was reviewed. METHODS: A total of 112 patients (mean age 29 +/- 10 years) underwent cross-sectional echocardiographic follow up. End-points of the study were freedom from autograft dilatation (diameter >4 cm, indexed as 0.21 cm/m2) and from reoperation for dilatation. Risk factors for autograft dilatation were also identified. RESULTS: There were 110 late survivors; average follow up was 5.1 +/- 1.9 years (range: 0.3 to 10.6 years). At 10 years, autograft dilatation was identified in 32 patients (29%), compatible with aortic aneurysm (>5.0 cm) in seven patients (6%). Seven of 32 patients (22%) presented moderate or greater autograft insufficiency. Ten-year freedom from dilatation was 43 +/- 8%, and from regurgitation was 75 +/- 8%. At multivariate analysis, preoperative aneurysm (p = 0.02), root replacement technique (p = 0.03) and absence of root buttressing (p = 0.04) were predictive of dilatation. Reoperation for autograft aneurysm was performed in five patients at a mean of 7.3 +/- 0.8 years after the Ross procedure, while two patients await reintervention. Two patients had root replacement and three remodeling with valve preservation (two root replacements, one sinotubular junction replacement): all survived reoperation. Ten-year freedom from root reoperation was 81 +/- 6%, and from full root replacement was 94 +/- 2%. CONCLUSION: With increasing follow up after the Ross operation, the incidences of root dilatation and reoperation are likely to rise. Graft replacement of coexisting aneurysm, avoidance of root replacement technique and the use of root-stabilization measures may reduce the prevalence of late root pathology. Early replacement of dilated autograft roots may allow preservation of the autologous pulmonary valve.     

Clinical and hemodynamic results of the mosaic bioprosthesis in aortic position

INTRODUCTION: Aim of the study was to evaluate the hemodynamic and clinical performance of the Mosaic bioprosthesis in the aortic position. PATIENTS AND METHODS: The Mosaic bioprosthesis is a stented porcine heart valve for implantation in the aortic and mitral position, which combines zero pressure and root pressure fixation with glutaraldehyde, antimineralization treatment with alpha amino oleic acid (AOA) and a low profile stent, to optimize hemodynamic function and to minimize mechanical wear and thus to achieve longer tissue durability. Included in a multicenter study, 100 patients (49 females) underwent isolated aortic valve replacement with the Mosaic bioprosthesis between February 1994 and May 1999. Average age at implant was 73.4 +/- 7.3 years (range 31.3-86.8 years). Preoperative and operative clinical data are shown in Tables 1 and 2. Patients were followed-up within the first 30 postoperative days, after six months and at annual intervals, including transthoracic echocardiography and documentation of any adverse events. Mean follow-up was 3.8 years (range 0.1-7.1 years), total 383.1 patient-years. Follow-up is 100% complete. RESULTS: One year after implantation of the bioprosthesis, mean systolic pressure gradient was 15.3 +/- 6.7 mmHg (21), 14.5 +/- 5.7 mmHg (23), 12.7 +/- 4.1 mmHg (25) and 13.0 +/- 4.8 mmHg (27); effective orifice area (EOA) was 1.4 +/- 0.4 cm2 (21), 1.7 +/- 0.4 cm2 (23), 1.8 +/- 0.4 cm2 (25) and 2.6 +/- 0.4 cm2 (27) (Table 3). One year postoperative, nine patients (10.8%) showed mild aortic regurgitation and one patient (1.2%) moderate. Left ventricular mass index decreased significantly for all sizes within the first postoperative year from 159.7 +/- 56.8 g/m2 to 137.3 +/- 40.8 g/m2. Separating the patients with regard to valve size, only the 21-group (154.1 +/- 51.2 g/m2 to 129.1 +/- 34.6 g/m2) and the 27-group (237.7 +/- 59.2 g/m2 to 146.7 +/- 20.6 g/m2) showed significant results. Freedom from event rates at seven years were 96.8 +/- 1.8% for thromboembolic events, 97.2 +/- 2.0% for thrombosed bioprosthesis, 96.6 +/- 2.6% for structural valve deterioration, 98.2% +/- 1.8% for nonstructural dysfunction, 95.9% +/- 2.0% for antithromboembolic hemorrhage, 98.9 +/- 1.1% for endocarditis and 93.9 +/- 3.2% for reoperation and explant (see Table 4). Early mortality (within 30 days) was 3.0%; late mortality was 4.6%/patient-year, including a valve-related mortality of 0.6%/patient-year. Of the patients, 96.5% showed an improvement of at least one NYHA class when comparing preoperative and one year status. DISCUSSION: The hemodynamic performance and the frequency of adverse events of the Mosaic bioprosthesis in the aortic position were very satisfactory within the first seven postoperative years with excellent results, comparable to studies about other established bioprostheses and similar to the findings in other Mosaic series. Only the number of cases of antithromboembolic hemorrhage was noticeably high. One reason might be the high percentage of patients under continuous anti-coagulant therapy: Six months postoperative, still 52.2% of the patients received phenprocoumon, 6.7% acetylsalicylic acid. Concerning hemodynamics, patient-prosthesis mismatch appeared to be a common problem, especially in small valve sizes. Separating the sample in groups with EOA index < or = 0.75 cm2/m2 and EOA index > 0.75 cm2/m2 after one year, 51.6% in the 21-group had an EOA index < or = 0.75 cm2/m2, whereas it was 19.4% (23), 18.8% (25) and 0% (27) in the larger size groups. Generally, further data have to be collected to determine durability of the biological tissue, as the critical period has just started with the seventh year of the clinical trial. CONCLUSION: The Mosaic bioprosthesis proved to be a reliable and well-functioning device for aortic valve replacement, especially in larger sizes.     

Left ventricular mass regression after aortic valve replacement with the new Mitroflow 12A pericardial bioprosthesis

BACKGROUND AND AIM OF THE STUDY: The study aim was to evaluate the durability of the new Mitroflow 12A pericardial bioprosthesis and to assess ventricular mass regression after aortic valve replacement (AVR) in patients with small valves. METHODS: A total of 326 Mitroflow 12A pericardial bioprostheses was implanted without any other associated valve procedure. The mean patient age was 73.5 +/- 6.1 years; 252 patients (78.0%) were in NYHA class III/IV. Small valves (19 and 21 mm) were implanted in 212 patients (65.6%). The total follow up period was 837.1 patient-years (pt-yr). A subset of 61 patients with preoperative stenosis was selected and submitted to conventional echo-Doppler assessment at a mean period of 11.1 months after surgery. RESULTS: Hospital mortality was 8.6%. At eight years of follow up, survival was 57.1%. Freedom from structural valve deterioration (SVD) was 86.5% per pt-yr. Mean gradients were significantly reduced postoperatively for each valve size (to 18 +/- 8 mmHg for 19-mm valves and 12 +/- 4 mmHg for 25-mm valves). The effective orifice area (EOA) was also increased significantly for all valve sizes (to 1.1 +/- 0.1 cm2 for 19-mm valves and 1.8 +/- 0.2 cm2 for 25-mm valves). The left ventricular mass index (LVMI) decreased significantly, from 177 +/- 29 to 136 +/- 22 g/m2 for the 19-mm valve, and from 200 +/- 42 to 132 +/- 22 g/m2 for the 25-mm valve. The EOA index (EOAI) showed mismatch for the 19- and 21-mm valves (0.74 and 0.82 cm2/m2, respectively). The diagrammatic calculation between LVMI and relative wall thickness after surgery showed that 29.7% of patients achieved a normal pattern of remodeling (including 19- and 21-mm valves), despite various degrees of mismatch. CONCLUSION: The new Mitroflow 12A pericardial bioprosthesis showed an absence of mechanical failure after an eight-year follow up, with a satisfactory rate of SVD. Significant reductions in LVMI and improved ventricular geometry were observed, despite the small valve sizes implanted.     

The influence of prosthesis size and design on exercise dynamics after aortic valve replacement

BACKGROUND AND AIM OF THE STUDY: Residual gradient following aortic valve replacement (AVR) may adversely affect clinical outcome. The size and design of the valve may influence these characteristics. The study aim was to determine the influence of prosthesis physical size and leaflet design on hemodynamic performance after mechanical AVR. METHODS: After AVR, two patient groups with a range of valve sizes were studied. Group 1 patients (n=19) each received a monoleaflet valve; group 2 patients (n=18) each received a bileaflet valve. Transthoracic echocardiography was performed at rest and after graded bicycle ergometry to assess prosthetic valve parameters, including mean and peak transvalvular gradient and effective orifice area (EOA). RESULTS: Transprosthetic gradients (mean and peak) measured at rest, maximum exercise and 3-min recovery were related to indexed geometric orifice area (IGOA) by an exponential decay function, with no significant advantage for either valve design. However, in valve sizes < or =25 mm the bileaflet valves demonstrated lower gradients, both at rest and under exercise conditions (mean gradient during exercise, bileaflet versus monoleaflet 19.9 +/- 7.2 mmHg versus 25.6 +/- 6.3 mmHg, p = 0.01). Similarly, EOAs were larger in the bileaflet group when equivalent GOAs < or =2.5 cm2 were compared (EOA: bileaflet versus monoleaflet 1.51 +/- 0.33 cm2 versus 1.14 +/- 0.26 cm2, p = 0.018). The total work performed correlated with prosthesis diameter (r2 = 0.81, p = 0.037) and was not influenced by valve design. CONCLUSION: The hemodynamic performance of mechanical aortic valves, including transprosthetic gradient and maximum exercise work performed, related principally to the prosthesis physical size. However, within the smaller valve sizes, the bileaflet design appeared to offer hemodynamic advantages.     

Clinical and hemodynamic performance of the 19-mm medtronic mosaic bioprosthesis

BACKGROUND AND AIM OF THE STUDY: The Medtronic Mosaic valve (MMV) is a latest generation supra-annular stented porcine valve, which combines a low-profile stent, leaflet fixation at zero pressure in a predilated aortic root, and amino-oleic acid anti-mineralization treatment for improved hemodynamics and durability. A study was conducted to evaluate the clinical and hemodynamic performances of the MMV in patients with a small aortic root (19 mm aortic annulus). METHODS: Between 1998 and 2004, 81 consecutive patients (69 females, 12 males; mean age 78.0 +/- 5.5 years) underwent aortic valve replacement using the 19-mm MMV. Concomitant coronary artery bypass grafting was performed in 28 patients (29.2%), and mitral valve surgery in one patient (1.2%). RESULTS: The 30-day mortality rate was 9.9% (eight deaths). Postoperative actuarial survival estimates were 90.1 +/- 3.3%, 78.5 +/- 4.6% and 69.1 +/- 5.5% at one month, one year and two years, respectively. After a mean follow up of 2.7 +/- 1.9 years, no cases of structural dysfunction, non-structural dysfunction or valve thrombosis were noted. Four ischemic cerebral complications (2.0% per patient-year (pt-yr)), five bleeding complications (2.0%/pt-yr) and two prosthetic valve infections (1.0%/pt-yr) were observed. No reoperation on a MMV was performed. Postoperatively, the mean systolic gradient was 23.4 +/- 7.0 mmHg, and the effective orifice area (EOA) 1.06 +/- 0.33 cm2. Valve prosthesis-patient mismatch (VP-PM) was moderate (indexed EOA > 0.65 cm2/m2 and < or = 0.85 cm2/m2) in 40 patients (49.4%), and severe (indexed EOA < or = 0.65 cm2/m2) in 41 (50.6%). CONCLUSION: Although providing acceptable clinical results, implantation of the 19-mm MMV resulted in a high incidence of postoperative VP-PM. Hence, this valve should be reserved for patients in whom the projected indexed EOA calculated preoperatively is deemed acceptable, given the patient's clinical condition.     

Rest and exercise Doppler hemodynamics of the Medtronic Intact aortic bioprosthesis.

BACKGROUND AND AIMS OF THE STUDY: Exercise treadmill testing was used to evaluate the functional rest and stress hemodynamic profile of the Medtronic Intact aortic bioprosthesis. METHODS: A group of 93 patients (mean age at operation 72.9 years; range: 61-79 years) was studied. Mean time to follow up was 20.8 months. The preoperative diagnosis was aortic stenosis (AS; n = 66), aortic regurgitation (AR; n = 19) or AS/AR (n = 8). Left ventricular function was assessed as normal (n = 78), moderate (n = 14) or poor (n = 1). Patients received a range of valve sizes: 21 mm (n = 7); 23 mm (n = 41); 25 mm (n = 32); 27 mm (n = 7); and 29 mm (n = 6). RESULTS: For all valve sizes, Doppler-derived hemodynamics at rest and peak exercise, respectively were: mean aortic valve gradient (AVG) 13.2 +/- 5.2 mmHg and 22.2 +/- 8.9 mmHg; peak aortic valve gradient (AVG) 24.3 +/- 9.6 mmHg and 39.1 +/- 13.5 mmHg; effective orifice area (EOA) 1.39 +/- 0.49 cm2 and 1.38 +/- 0.5 cm2; and effective orifice area index (EOAI) 0.76 +/- 0.26 cm2/m2 and 0.75 +/- 0.26 cm2/m2. Mean and peak AVG decreased as valve sizes increased, while both EOA and EOAI increased as valve sizes increased. CONCLUSIONS: The Medtronic Intact aortic bioprosthesis provides good hemodynamics both at rest and exercise, across the range of implanted valve sizes.     

Rest and exercise hemodynamics before and after valve replacement--a combined Doppler/catheter study

BACKGROUND: Hemodynamic improvement is a common finding following valve replacement. However, despite a normally functioning prosthesis and normal left ventricular ejection fraction, some patients may show an abnormal hemodynamic response to exercise. METHODS: In a combined catheter/Doppler study, rest and exercise hemodynamics were evaluated in 23 patients following aortic (n = 12) (Group 1) or mitral valve (n = 11) (Group 2) replacement and compared with preoperative findings. Patient selection was based on absence of coronary artery disease and left ventricular failure as shown by preoperative angiography. Cardiac output, pulmonary artery pressure, pulmonary capillary pressure, and pulmonary resistance were measured by right heart catheterization, whereas the gradient across the valve prosthesis was determined by Doppler echocardiography. Postoperative evaluation was done at rest and during exercise. The mean follow-up was 8.2 +/- 2.2 years in Group 1 and 4.2 +/- 1 years in Group 2. RESULTS: With exercise, there was a significant rise in cardiac output in both groups. In Group 1, mean pulmonary pressure/capillary pressure decreased from 24 +/- 9/18 +/- 9 mmHg preoperatively to 18 +/- 2/12 +/- 4 mmHg postoperatively (p < 0.05), and increased to 43 +/- 12/30 +/- 8 mmHg with exercise (p < 0.05). The corresponding values for Group 2 were 36 +/- 12/24 +/- 6 mmHg preoperatively, 24 +/- 7/17 +/- 6 mmHg postoperatively (p < 0.05), and 51 +/- 2/38 +/- 4 mmHg with exercise (p < 0.05). Pulmonary vascular resistance was 109 +/- 56 dyne.s.cm-5 preoperatively, 70 +/- 39 dyne.s.cm-5 postoperatively (p < 0.05), and 70 +/- 36 dyne.s.cm-5 with exercise in Group 1. The corresponding values for Group 2 were 241 +/- 155 dyne.s.cm-5, 116 +/- 39 dyne.s.cm-5 (p < 0.05), and 104 +/- 47 dyne.s.cm-5. There was a significant increase in the gradients across the valve prosthesis in both groups, showing a significant correlation between the gradient at rest and exercise. No correlation was found between valve prosthesis gradient and pulmonary pressures. CONCLUSION: Exercise-induced pulmonary hypertension and abnormal left ventricular filling pressures seem to be a frequent finding following aortic or mitral valve replacement. Both hemodynamic abnormalities seem not to be determined by obstruction to flow across the valve prosthesis and may be concealed, showing nearly normal values at rest but a pathologic response to physical stress.