Determinants of ascending aortic dimensions after aortic valve replacement with a stented bioprosthesis.

BACKGROUND AND AIM OF THE STUDY: Concomitant replacement of the mildly dilated ascending aorta during aortic valve replacement (AVR) is controversial because progress of aortic dilatation is uncertain after elimination of the valvular lesion. The study aim was to determine factors influencing the aortic dimensions, to analyze their clinical impact, and to identify criteria for concomitant surgery on the aorta. METHODS: Between February 1994 and May 1999, 100 patients with tricuspid aortic valve disease received the stented porcine Mosaic prosthesis within a FDA approval study. Follow up (mean 4.8 years; range: 0.1-8.8 years; total 483.4 patient-years) included documentation of adverse events and transthoracic echocardiography with measurements of the aortic sinus, sinotubular junction, and ascending aorta. RESULTS: Baseline aortic dimensions were dependent on gender and body surface area, but independent of the type and extent of valvular lesion, patient age, and atherosclerotic risk factors. Larger baseline aortic diameters were associated with smaller postoperative annual aortic expansion rates (r = -0.47, p <0.001). In patients with baseline aortic dilatation > or =40 mm (10.2%; mean 42.5+/-2.6 mm), aortic diameter decreased during follow up (p = 0.032; expansion rate -1.9+/-2.0 mm/year). Baseline aortic dilatation did not influence postoperative morbidity and mortality. Prosthetic regurgitation was associated with increases in aortic diameter (p <0.001). Survival was reduced in patients with aortic expansion rates >3.6 mm/year (0.0% versus 68.2+/-9.7%; p <0.001). CONCLUSION: AVR without concomitant surgery on the aorta in patients with mild aortic dilatation is feasible, as aortic diameters were decreased after removal of the diseased valve. The aortic expansion rate had a strong prognostic importance, even on aortic diameters, which are considered to be within normal ranges.

Hemodynamic comparison of bioprostheses for complete supra-annular position in patients with small aortic annulus.

OBJECTIVES: The present study evaluates complete supra-annular bioprostheses in patients with an aortic annulus of 18 to 23 mm in diameter. BACKGROUND: Aortic valve replacement in patients with small aortic annulus using stented bioprostheses is often associated with unsatisfactory hemodynamic results and high incidence of patient-prosthesis mismatch. METHODS: Between February 2000 and January 2004, 156 patients with aortic valve disease and an aortic annulus of 18 to 23 mm in diameter received the stented bovine Soprano (Sorin Biomedica Cardio, Saluggia, Italy) (n = 18), Perimount (Edwards Lifesciences, Irvine, California) (n = 52), Perimount Magna (Edwards Lifesciences) (n = 42), or the stented porcine Mosaic (Medtronic Inc., Minneapolis, Minnesota) (n = 44) bioprostheses. Intraoperatively, the surgeon measured the aortic annulus diameter by inserting a hegar dilator. Thus, postoperative hemodynamic results could be referred to the patient's aortic annulus diameter instead of referring the results to the labeled valve size. This allows for objective comparisons between different valve types. RESULTS: There was no significant difference in hemodynamic results between the different valve types in patients with an aortic annulus 18 to 20 mm. In patients with an annulus 21 to 23 mm, the Magna was significantly superior to the other investigated devices in mean pressure gradient, effective orifice area, and incidence of patient-prosthesis mismatch. There was no significant difference between the complete supra-annular bioprostheses Mosaic and Soprano and the intra-supra-annular Perimount valve. CONCLUSIONS: In patients with an aortic annulus of 18 to 20 mm in diameter, hemodynamic performance is independent of the implanted stented valve type and the annular position. Root enlargement or stentless valves may be beneficial alternatives. Patients with annulus diameter 21 to 23 mm benefit from the Magna in complete supra-annular position leading to superior hemodynamic results.

Exercise hemodynamics of bovine versus porcine bioprostheses: a prospective randomized comparison of the mosaic and perimount aortic valves.

OBJECTIVE: This prospective randomized study compares a porcine with a bovine bioprosthesis in the aortic position with regard to hemodynamic performance during exercise. METHODS: Between August of 2000 and December of 2002, 136 patients underwent aortic valve replacement with the porcine Medtronic Mosaic (n = 66) or the bovine Carpentier-Edwards Perimount (n = 70) bioprosthesis. Transthoracic echocardiography was performed to assess hemodynamic and dimensional data preoperatively and 10 months postoperatively; the latter follow-up included stress echocardiography with treadmill exercise. RESULTS: At rest and during exercise (25 and 50 W), there was a significant difference in mean pressure gradient between the bovine and the porcine valves with labeled sizes 21 and 23, with superiority of the Perimount prosthesis. There was no difference in effective orifice area and incidence of patient-prosthesis mismatch among all sizes. The left ventricular mass index decreased significantly within 10 months postoperatively in the size 23 bovine group and the size 25 porcine group. CONCLUSIONS: Our data show a significant superiority of pressure gradients for the bovine bioprosthesis, especially with small valve sizes, when compared with the porcine device, which is more distinctive during exercise.

Hemodynamic evaluation of the Sorin Soprano bioprosthesis in the completely supra-annular aortic position.

BACKGROUND AND AIM OF THE STUDY: The study aim was to evaluate the clinical and hemodynamic performance of the Sorin Soprano bioprosthesis in the aortic position. METHODS: Rest and stress echocardiography were performed at six months after surgery in 57 patients who underwent aortic valve replacement with the stented Soprano bioprosthesis. The exercise protocol included workloads of 25, 50, 75 and 100 W, each of 2 min duration. RESULTS: Thirty-day mortality was 1.8% (n = 1). Due to malperfusion of the coronary arteries, two Soprano prostheses had to be replaced by a different prosthesis, and one patient received coronary artery bypass grafts. One patient developed bacterial endocarditis of his prosthesis at seven months postoperatively and died as a result of a fulminant sepsis. There were no other prosthesis-related adverse events. Mean pressure gradients (MPG) ranged from 7.8 to 15.9 mmHg, effective orifice areas (EOA) from 1.25 to 2.98 cm2, EOA index (EOAI) from 0.79 to 1.43 cm2/m2, and EOA fraction from 34 to 45%. Stress echocardiography showed no significant increase in MPG up to 50 W, and MPGs did not exceed 35 mmHg at 75 and 100 W. CONCLUSION: Initial hemodynamic results showed low MPGs during rest and exercise. The EOAI was large due to completely supra-annular placement of the Soprano valve. The difficulty of complete supraannular placement is that the prosthesis is positioned relatively high, especially in narrow aortic roots, and this may handicap coronary artery perfusion. Patient selection with suitable aortic root anatomy is crucial to achieve the benefit of completely supra-annular implantation without coronary ostium deterioration.

European experience with the Mosaic bioprosthesis.

OBJECTIVE: The purpose of this study was to prospectively evaluate the clinical and hemodynamic performance of the Mosaic bioprosthesis (Medtronic, Inc, Minneapolis, Minn). METHODS: The stented porcine bioprosthesis combines the amino-oleic acid antimineralization treatment and the zero-pressure differential fixation technique for improved tissue durability. From February 1994 to May 1999, a total of 561 patients underwent valve replacement with the Mosaic bioprosthesis at 5 centers in Europe: 461 in the aortic and 100 in the mitral position. There were 261 women and 300 men; mean age at implantation was 70 years (range, 23-89 years). Mean follow-up was 2.9 years (range, 0-6.2 years), with a total follow-up of 1710.1 patient-years. RESULTS: Postoperative mortality was 4.2% per patient-year, including a valve-related mortality of 0.4% per patient-year. The freedom from event rates in the aortic position at 5 years and in the mitral position at 4 years were, respectively, 96.6% +/- 1.1% and 94.9% +/- 3.3% for primary thromboembolism, 96.4% +/- 5.0% and 87.1% +/- 4.8% for antithromboembolic-related hemorrhage, 99.1% +/- 0.5% and 100% for thrombosed prosthesis, 98.8% +/- 1.2% and 100% for structural valve deterioration, 98.8% +/- 0.7% and 100% for nonstructural dysfunction, 98.4% +/- 0.6% and 94.4% +/- 3.8% for endocarditis, and 95.4% +/- 1.6% and 95.3% +/- 3.7% for explant and reoperation. Mean pressure gradient values at 5 years ranged from 7.5 to 15.9 mm Hg in the aortic position and at 4 years from 2.0 to 6.9 mm Hg in the mitral position across all valve sizes. CONCLUSIONS: Clinical and hemodynamic performance of the Mosaic bioprosthesis were very satisfactory during the first 6 years after clinical introduction.

The Mosaic bioprosthesis in the aortic position: seven years' results.

BACKGROUND AND AIM OF THE STUDY: The Mosaic bioprosthesis is a stented porcine aortic valve, which combines glutaraldehyde fixation with zero-pressure and root-pressure techniques and anti-mineralization treatment with amino-oleic acid for improved hemodynamics and tissue durability. The study aim was to collect intermediate-term data of the Mosaic bioprosthesis in the aortic position, the first device having been implanted in February 1994 at the authors' institution. METHODS: A total of 100 patients (49 females, 51 males) underwent aortic valve replacement with the Mosaic bioprosthesis between February 1994 and May 1999. Mean age at implant was 73.4 +/- 7.3 years. Concomitant procedures were performed in 40.0% of cases. Patients were followed up within 30 days postoperatively, after six months, and at annual intervals thereafter. Mean follow up was 3.8 years (range: 0.1-7.1 years); total follow up was 383.1 patient-years (pt-yr) and 100% complete. RESULTS: Early mortality (< or = 30 days) was 3.0%; late mortality was 4.6%/pt-yr, including a valve-related mortality of 0.6%/pt-yr. Freedom from event at seven years was 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 anti-thromboembolic hemorrhage, 98.9 +/- 1.1% for endocarditis, and 93.9 +/- 3.2% for reoperation/explant. After one year, the mean systolic pressure gradient was 15.3 +/- 6.7, 14.5 +/- 5.7, 12.7 +/- 4.1 and 12.9 +/- 4.8 mmHg for 21, 23, 25 and 27 mm valves respectively; the effective orifice area (EOA) was 1.4 +/- 0.4, 1.7 +/- 0.4, 1.8 +/- 0.4 and 2.6 +/- 0.4 cm2 for 21, 23, 25 and 27 mm valves respectively; and the EOA index was 0.8 +/- 0.3, 0.9 +/- 0.2, 0.9 +/- 0.2 and 1.3 +/- 0.1 cm2/m2 respectively. The mean left ventricular mass index was decreased significantly, from 159.7 +/- 56.8 g/m2 to 137.3 +/- 40.8 g/m2, for all valve sizes after one year. CONCLUSION: Clinical and hemodynamic performance of the Mosaic bioprosthesis was highly satisfactory during the first seven years after clinical introduction.

The effective orifice area/patient aortic annulus area ratio: a better way to compare different bioprostheses? A prospective randomized comparison of the Mosaic and Perimount bioprostheses in the aortic position.

BACKGROUND AND AIM OF THE STUDY: The aim of this prospective, randomized study was to compare the hemodynamic performance of the Medtronic Mosaic and Edwards Perimount bioprostheses in the aortic position, and to evaluate prosthesis-specific differences in valve sizing and valve-size labeling. METHODS: Between August 2000 and September 2002, 139 patients underwent isolated aortic valve replacement (AVR) with the Mosaic (n = 67) or Perimount (n = 72) bioprosthesis. Intraoperatively, the internal aortic annulus diameter was measured by insertion of a gauge (Hegar dilator), while prosthesis size was determined by using the original sizers. Transthoracic echocardiography was performed to determine hemodynamic and dimensional data. As the aim of AVR is to achieve a maximal effective orifice area (EOA) within a given aortic annulus, the ratio of EOA to patient aortic annulus area was calculated, the latter being based on annulus diameter measured intraoperatively. RESULTS: Operative mortality was 2.2% (Mosaic 3.0%; Perimount 1.4%; p = NS). Upsizing (using a prosthesis larger in labeled valve size than the patient's measured internal aortic annulus diameter) was possible in 28.4% of Mosaic patients and 8.3% of Perimount patients. The postoperative mean systolic pressure gradient ranged from 10.5 to 22.2 mmHg in the Mosaic group, and from 9.4 to 12.6 mmHg in the Perimount group; it was significantly lower for 21 and 23 Perimount valves than for 21 and 23 Mosaic valves. The EOA ranged from 0.78 to 2.37 cm2 in Mosaic patients, and from 0.95 to 2.12 cm2 in Perimount patients. When indexing EOA by calculating the ratio of EOA to patient aortic annulus area to adjust for variables such as patient anatomy and valve dimensions, there was no significant difference between the two bioprostheses. CONCLUSION: Comparisons of absolute EOA values grouped by the manufacturers' valve sizes are misleading because of specific differences in geometric dimensions. The EOA:patient aortic annulus area ratio provides a new hemodynamic index which may facilitate objective comparisons between different valve types.

Left ventricular mass regression after aortic valve replacement with the mosaic bioprosthesis.

BACKGROUND AND AIMS OF THE STUDY: The study aim was to evaluate the hemodynamic performance and extent of left ventricular (LV) mass regression after aortic valve replacement (AVR) with the Mosaic bioprosthesis within the first postoperative year. METHODS: Between 1994 and 1999, 366 patients (203 males, 163 females) underwent AVR with the Mosaic bioprosthesis at five centers in Europe. Mean age at implant was 71.1 years (range: 34.5-86.8 years). LV mass assessment and hemodynamic evaluation were performed using transthoracic echocardiography within six days postoperatively, after six months, and at annual intervals thereafter. RESULTS: LV mass index decreased significantly in patients with valve sizes 21 to 27 mm, from 184.4+/-56.2 g/m2 postoperatively to 157.3+/-45.5 g/m2 after one year (14.7% decrease). The 19-mm valve group did not show significant LV mass index reduction (from 210.4+/-39.4 to 195.0+/-59.4 g/m2; 7.3%). Patients with significant LV mass index regression had survival benefits after seven years. Mean pressure gradients after one year were 16.0+/-4.3, 14.2+/-5.4, 12.8+/-5.3, 11.1+/-4.0 and 10.5+/-3.7 mmHg for 19, 21, 23, 25 and 27 mm valves, respectively. CONCLUSION: Implantation of the Mosaic bioprosthesis resulted in a significant regression of LV mass for the valves sizes 21 to 27 mm, corresponding to very low pressure gradients for a stented bioprosthesis.

In-vivo bacterial adherence to intracardiac prosthetic materials: a new experimental model.

BACKGROUND AND AIM OF THE STUDY: Bacterial colonization of inert artificial materials is a critical variable in the appearance of foreign body-centered infections. Hence, a new experimental endocarditis model was evaluated that enables quantitative in-vivo testing of bacterial adherence to prosthetic materials. METHODS: In 53 rabbits, different patches of either Dacron (DAC; n = 16), glutaraldehyde-fixed pericardium (GAP; n = 18) or cryopreserved allograft (AG; n = 19) were threaded onto a Prolene suture and led through a stitch incision at the left atrium to the ventricle, perforating the mitral valve and leaving the heart at the outside of the left ventricle. The patch became caught in the valve tissue, creating mitral insufficiency. At 6 h after surgery, 6 x 10(6) colony-forming units (CFU) of Staphylococcus aureus were administered intravenously. Postmortem examination and further analysis were carried out 48 h after bacterial inoculation. RESULTS: Ten animals (two DAC, four GAP, four AG) died and were excluded. Subsequently, sterile patches were found in 6/14 animals of the DAC group, in 9/14 of the GAP group, and in 9/15 of the AG group. The mean numbers of cultured organisms in the remaining patches were 2.3 x 10(6) + 7.6 x 10(6)/mg (DAC), 1.8 x 10(4)+/-6.7 x 10(4)/mg (GAP) and 4.9 x 10(5)+/-1.0 x 10(6) CFU/mg (AG). Differences in the number of CFU were not significant for all groups. CONCLUSION: The above-described model allows reliable quantitative in-vivo testing of bacterial adherence to different prosthetic materials within a short time period. The results suggest that, with regard to avoiding the development of bacterial endocarditis, biomaterials have no advantage over Dacron.

Investigation of various types of neurocardiogenic response to head-up tilting by extended hemodynamic and neurohumoral monitoring.

BACKGROUND: The pathophysiology of neurocardiogenic syncope is heterogeneous. This study aim was to analyze whether extended monitoring during tilt-table testing provided additional information on the hemodynamic and vegetative state prior to neurocardiogenic syncope. METHODS: This retrospective analysis is based on data of head-up tilt-table testing of 40 unselected consecutive patients with a history of unexplained syncope. For optimized characterization of the type of syncope, monitoring included electrocardiogram (ECG), blood pressure measurements and cardiac output, peripheral vascular resistance and contractility index measurements by impedance cardiography, as well as epinephrine and norepinephrine plasma levels in supine position and every 5 min during tilting. RESULTS: Seven of 40 patients were unsuitable for analysis because of incomplete data sets. Tilt-table was positive in 26 patients, negative in 7. Groups did not differ in hemodynamic and catecholaminergic parameters at baseline. Responses to tilting were VASIS 1 (mix of cardioinhibitory and vasodepressor) in 5 patients, VASIS 2B (cardioinhibitory with asystole >3 sec) in 3, VASIS 3 (vasodepressor) in 16, orthostatic dysregulation in 2. In VASIS 1, the catecholamine measurement 4 min before syncope showed a proportionally larger increase of the epinephrine level than of norepinephrine. This disproportion was not observed in VASIS 2B and 3. In VASIS 2B, strong vasoconstriction and negative inotropy were evident in the presyncopal period. In VASIS 3, vascular resistance decreased continuously before syncope, while contractility index increased inadequately. Presyncopal epinephrine surge or norepinephrine loss was not observed in this group, suspecting other vasodilating factors. CONCLUSIONS: Extended monitoring by impedance cardiography and plasma catecholamine measurements during tilt-table testing gave further insight into different hemodynamic and neurohumoral presyncopal patterns among the various types of neurocardiogenic syncope and may thereby help to develop individualized therapeutic concepts.

Quality of internal thoracic artery grafts after mediastinal irradiation.

BACKGROUND: With the increase of patients of advanced age requiring coronary artery bypass grafting (CABG), the number of those with previous mastectomy and irradiation of the chest increases proportionally. The question of whether mediastinal irradiation leads to relevant internal thoracic artery (ITA) graft damage remains unclear. The aim of the present study was to proof the quality of ITAs and to evaluate the early clinical outcome after using one or both ITAs in this specific population. METHODS: One hundred twenty-five patients (group A) with previous mastectomy or Hodgkin/non-Hodgkin disease and mediastinal irradiation operated on between January 1993 and September 2006 underwent CABG (n = 88) or CABG plus valve replacement (n = 37). Sixty-two patients received bilateral, 43 received unilateral ITAs, and 20 patients received veins. Postoperative complications and mortality were analyzed and compared with a propensity score pair-matched control group of 125 patients receiving CABG or CABG plus valve replacement within the same period (group B). A histomorphologic investigation was performed in 133 irradiated distal ITA segments and compared with a control group of 133 nonirradiated ITAs. RESULTS: Thirty-day mortality revealed 3.2% in group A versus 5.6% in group B. Sternal instabilities were more frequent in group A (3.2%) than in group B (0%). Mediastinitis occurred in 1.6% (group A) versus 1.6% (group B). Histomorphologic investigations did not identify any severe irradiation induced fibrosis or damage of ITA grafts. CONCLUSIONS: From the histologic point of view, there is no need for restrictions in use of ITA conduits after mediastinal irradiation. Compared with a control group, cardiac surgery was associated with a slightly enhanced incidence of sternal instabilities.

Influence of completely supra-annular placement of bioprostheses on exercise hemodynamics in patients with a small aortic annulus.

OBJECTIVE: Aortic valve replacement in patients with a small aortic annulus is often associated with increased pressure gradients. For this reason, prostheses for completely supra-annular placement have been developed. To evaluate the potential benefit of this design, the present study compared the effectiveness of 1 intra-supra-annular bioprosthesis and 3 completely supra-annular bioprostheses in patients with an aortic annulus diameter of 23 mm or less. METHODS: Between August 2000 and December 2004, each of 192 patients requiring aortic valve replacement with an intraoperatively measured aortic annulus diameter of 23 mm or less received one of the following bioprostheses: the stented bovine Sorin Soprano bioprosthesis (n = 28) (Sorin Group, Saluggia, Italy), the Carpentier-Edwards Perimount bioprosthesis (n = 50) (Edwards Lifesciences, Irvine, Calif), the Carpentier-Edwards Perimount Magna bioprosthesis (n = 70) (Edwards Lifesciences), or the stented porcine Medtronic Mosaic (n = 44) (Medtronic Inc, Minneapolis, Minn) bioprosthesis. After 6 months, hemodynamic data at rest and during exercise were obtained by echocardiography in 142 patients. RESULTS: The pericardial valves showed lower mean systolic pressure gradients, larger effective orifice areas and indices, and superior effective orifice fractions than did the porcine valve (P < .05) (Carpentier-Edwards Perimount: 10.9 +/- 3.6 mm Hg, 1.59 +/- 0.41 cm2, 0.9 +/- 0.25 cm2/m2, 41.9% +/- 9.6%; Carpentier-Edwards Perimount Magna 10.1 +/- 3.8 mm Hg, 1.64 +/- 0.38 cm2, 0.93 +/- 0.22 cm2/m2, 45.1% +/- 10.2%; Sorin Soprano 13.5 +/- 5.0 mm Hg, 1.64 +/- 0.32 cm2, 0.92 +/- 0.15 cm2/m2, 45.8% +/- 9.0%; vs Medtronic Mosaic 15.5 +/- 5.2 mm Hg, 1.31 +/- 0.42 cm2, 0.75 +/- 0.24 cm2/m2, 35.2% +/- 10.0%, respectively). The lowest mean systolic pressure gradients were found after the implantation of the Carpentier-Edwards Perimount Magna. Effective orifice areas, indices, and fractions of the pericardial valves did not show significant differences. CONCLUSIONS: In patients with small aortic roots, transvalvular gradients and effective orifice area showed a tendency to superior results in pericardial valves compared with the porcine bioprosthesis. However, the completely supra-annular design does not necessarily lead to superior hemodynamic results compared with the intra-supra-annular position.

Rest and exercise performance of the Medtronic Advantage bileaflet valve in the aortic position.

BACKGROUND: The aim of the study was to evaluate rest and exercise performance and left ventricular mass regression of the Medtronic Advantage (Medtronic, Inc, Minneapolis, MN) prosthesis in the aortic position at 1 year at a single center as part of a multicenter, prospective clinical trial. METHODS: Between May 2002 and June 2003, 63 consecutive patients underwent aortic valve replacement with a Medtronic Advantage prosthesis (84.1% male; mean age, 56.0 +/- 9.7 years; ejection fraction, 56.5 +/- 15.8%). Valve lesions were stenosis (n = 20), mixed (n = 34), and insufficiency (n = 9). Concomitant procedures were performed in 34.9%. Follow-up was 100% complete. Echocardiographic data were obtained early postoperatively and at 1 year, combined with stress echocardiography by treadmill. Mean pressure gradients, stroke volume, and left ventricular mass were determined by echocardiography. Data are presented as mean +/- standard deviation. RESULTS: Operative mortality was 0%. Valve-related complications were observed in 2 patients (endocarditis, n = 1; thromboembolic event, n = 1). There was no case of antithromboembolic hemorrhage, prosthesis-related explant, or reoperation. One patient showed moderate paravalvular regurgitation. Mean pressure gradients 1 year postoperatively ranged from 6.3 to 11.0 mm Hg across all valve sizes. Left ventricular mass regression at 1 year was 18.4% across all valve sizes (p < 0.001). No severe patient-prosthesis mismatch (effective orifice area index < or = 0.65 cm2/m2) could be observed. CONCLUSIONS: After 1 year, the Medtronic Advantage valve shows comparable transvalvular mean pressure gradients across the valve sizes used during rest and exercise. This is accompanied by a significant left ventricular mass regression, an important indicator for long-term survival.