Clinical and hemodynamic assessment of the Hancock II bioprosthesis

Alterations in Layer-Specific Left Ventricular Global Longitudinal and Circumferential Strain in Patients With Aortic Stenosis: A Comparison of Aortic Valve Replacement versus Conservative Management Over a 12-Month Period

BACKGROUND

Impairment in left ventricular (LV) systolic strain in aortic stenosis (AS) is well documented. However, alterations in layer-specific LV global longitudinal strain (GLS) and global circumferential strain (GCS) and their recovery following surgical aortic valve replacement (AVR) have not been established. The aim of this study was to examine layer-specific changes in GLS and GCS in patients with AS undergoing AVR and compare these patients with those managed conservatively over 12 months.

METHODS

Eighty-six patients (mean age, 68.8 ± 12 years; 60 men) with AS (19 mild, 15 moderate, and 52 severe) were prospectively recruited. Patients with coronary disease or other significant valvular disease were excluded. Forty patients (46.5%) with severe AS underwent AVR. All patients underwent baseline echocardiography. Patients managed conservatively underwent follow-up echocardiography at 12 months. Patients undergoing AVR underwent follow-up echocardiography at 1 week and 3, 6, and 12 months after AVR.

RESULTS

There was worsening in subendocardial but not subepicardial or transmural GLS even in mild AS (-20.9 ± 1.0% vs -20.6 ± 0.8%, P = .012). In moderate AS, worsening in subendocardial (-19.6 ± 0.9% vs -18.2 ± 1.5%, P = .003), subepicardial (-14.9 ± 1.0% vs -13.8 ± 1.2%, P = .004), and transmural (-17.1 ± 0.9% vs -15.8 ± 1.3%, P = .03) GLS and a trend toward significant worsening in subendocardial GCS (-29.8 ± 5.16% vs -27.5 ± 5%, P = .054) were seen. Conservatively managed patients with severe AS had significant worsening in subendocardial (-16.1 ± 1.6% vs -13.9 ± 2.6%, P = .021), subepicardial (-11.6 ± 1.1% vs -10.1 ± 2.1%, P = .027), and transmural (-13.6 ± 1.3% vs -11.8 ± 2.3%, P = .02) GLS and subendocardial (-24.9 ± 3.6% vs -20.8 ± 4.5%, P = .002) and transmural (-16.9 ± 1.7% vs -14.3 ± 3.5%, P = .04) GCS on follow-up. Patients after AVR demonstrated significant improvement in GLS (from 3 months) and GCS (from 6 months) in both myocardial layers.

CONCLUSIONS

Patients with AS managed conservatively had worsening of GLS over 12 months despite preserved LV ejection fraction, detected earliest in the subendocardial layer. GCS became progressively impaired in moderate and severe AS. Improvement in LV strain after AVR was seen earlier with GLS (from 3 months) than with GCS (from 6 months) in both myocardial layers.

Carpentier-Edwards Bioprosthesis: Structural Deterioration by Age Groups

The Carpentier-Edwards supra-annular porcine bioprosthesis (second generation prosthesis) was implanted in 2438 patients in 2482 operations between 1982 and 1992. The mean age of the population was 64 years with a range from 21 years to 89 years. There were 1334 aortic and 934 mitral valve replacements. The population was divided into five groups: 21 to 40 years (n = 132); 41 to 50 years (n = 189); 51 to 60 years (n = 454); 61 to 70 years (n = 849); and over 70 years (n = 858). There was no difference in sunival by valve position for age groups 21 to 40 years and 41 to 50 years. Sunival within the age groups 51 to 60 years, 61 to 70 years, and over 70 years was greater for patients with aortic compared with mitral and multiple valve replacements. The freedom from structural valve deterioration at 10 years for all age groups was highest for valves in the aortic position. Patients with valves in the mitral position had a higher freedom from structural valve deterioration at 10 years than those who had multiple valve replacement, although not all the differences were significant. There was a lower incidence of structural valve deterioration in the older age groups. We concluded that the use of the Carpentier-Edwards supra-annular porcine bioprosthesis for aortic valve replacement can be extended to patients over 60 years of age, while its use for mitral valve replacement can be extended to those above 70 years of age.

Carpentier-Edwards pericardial valve in the aortic position: 25-years experience

BACKGROUND

The Carpentier-Edwards pericardial valve was designed to minimize structural valve deterioration. Excellent durability and low incidence of valve-related complications have been reported. The objective of the present study was to analyze clinical results after 25 years of experience with this valve implanted in the aortic position. The effect of patient age at the time of surgery was also evaluated.

METHODS

This is a retrospective cohort study of 2,405 patients from November 1981 to March 2011. Primary outcomes of interest were survival and freedom from major adverse effects such as thromboembolic, endocarditis, and reoperation.

RESULTS

Sixty percent were male, with a mean age of 71 ± 9 years old. Actuarial survival rates including early deaths averaged 78% ± 2%, 55% ± 2%, and 16 % ± 2% after 5, 10, and 20 years of follow-up, respectively. The freedom rate of valve reoperation for prosthesis dysfunction and all other causes averaged 98 % ± 0.2%, 96% ± 1%, and 67% ± 4% at 5, 10, and 20 years. Patients younger than 60 years of age had a 15-year survival averaging 54% ± 5% compared with patients aged between 60 and 70 years of age averaging 46% ± 3% and with patients older than 70 years of age averaging 28% ± 3% (p = 0.001). Survival at 5, 10, and 20 years for patients who had concomitant CABG [coronary artery bypass grafting] were 78% ± 1%, 55% ± 2%, and 9% ± 3% compared with no concomitant CABG (84% ± 1%, 62% ± 2%, and 22% ± 3% (p < 0.001)).

CONCLUSIONS

Carpentier-Edwards pericardial valve implantation in the aortic position is secure and durable. The effects of age influence reoperation rate and survival as well as a concomitant coronary artery bypass procedure.

Speckle tracking echocardiography derived 2-dimensional myocardial strain predicts left ventricular function and mass regression in aortic stenosis patients undergoing aortic valve replacement

Regression of left ventricular (LV) mass in severe aortic stenosis (AS) following aortic valve replacement (AVR) reduces the potential risk of sudden death and congestive heart failure associated with LV hypertrophy. We investigated whether abnormalities of resting LV deformation in severe AS can predict the lack of regression of LV mass following AVR. Two-dimensional speckle tracking echocardiography (STE) was performed in a total of 100 subjects including 60 consecutive patients with severe AS having normal LV ejection fraction (EF > 50 %) and 40 controls. STE was performed preoperatively and at 4 months following AVR, including longitudinal strain assessed from the apical 4-chamber and 2-chamber views and the circumferential and rotational mechanics measured from the apical short axis view. In comparison with controls, the patients with AS showed a significantly lower LV longitudinal (p < 0.001) and circumferential strain (p < 0.05) and higher apical rotation (p < 0.001). Following AVR, a significant improvement was seen in both strains (p < 0.001 for each respectively), however, apical rotation remained unchanged (p = 0.14). On multivariate analysis, baseline LV mass (odds ratio 1.02; p = 0.011), left atrial volume (odds ratio 0.81; p = 0.048) and circumferential strain (odds ratio 0.84; p = 0.02) independently predicted LV mass regression (>10 %) following AVR. In conclusion, STE can quantify the burden of myocardial dysfunction in patients with severe AS despite the presence of normal LV ejection fraction. Furthermore, resting abnormalities in circumferential strain at LV apex is related with a hemodynamic milieu associated with the lack of LV mass regression during short-term follow up after AVR.

Diagnostic evaluation of left-sided prosthetic heart valve dysfunction

Prosthetic heart valve (PHV) dysfunction is a rare, but potentially life-threatening, complication. In clinical practice, PHV dysfunction poses a diagnostic dilemma. Echocardiography and fluoroscopy are the imaging techniques of choice and are routinely used in daily practice. However, these techniques sometimes fail to determine the specific cause of PHV dysfunction, which is crucial to the selection of the appropriate treatment strategy. Multidetector-row CT (MDCT) can be of additional value in diagnosing the specific cause of PHV dysfunction and provides valuable complimentary information for surgical planning in case of reoperation. Cardiac magnetic resonance imaging (CMR) has limited value in the evaluation of biological PHV dysfunction. In this Review, we discuss the use of established imaging modalities for the detection of left-sided mechanical and biological PHV dysfunction and discuss the complementary role of MDCT in this context.

Factors affecting survival after mitral valve replacement in patients with prosthesis-patient mismatch

BACKGROUND

The purpose of this study was to determine the impact of prosthesis-patient mismatch on long-term survival after mitral valve replacement.

METHODS

From 1992 to 2008, 765 patients underwent bioprosthetic (325; 42%) or mechanical (440; 58%) mitral valve replacement, including 370 (48%) patients older than 65 years of age. Prosthesis-patient mismatch was defined as severe (prosthetic effective orifice area to body surface area ratio <0.9 cm(2)/m(2)), moderate (0.9 to 1.2 cm(2)/m(2)), or absent (>1.2 cm(2)/m(2)).

RESULTS

Multivariate analysis identified nine risk factors for late death including advanced age, earlier operative year, chronic renal insufficiency, peripheral vascular disease, congestive heart failure, nonrheumatic origin, concomitant coronary artery bypass grafting, lower body surface area, and more severe prosthesis-patient mismatch (lower effective orifice area to body surface area ratio; p < 0.05). For bioprosthetic recipients older than 65 years of age, survival at 5 and 10 years was 30% ± 7% and 0% ± 0% with severe mismatch compared with 43% ± 4% and 21% ± 5% for absent or moderate mismatch, respectively (p = 0.05). For mechanical recipients younger than 65 years of age, survival at 5 and 10 years was 77% ± 4% and 62% ± 6% with moderate or severe mismatch compared with 82% ± 3% and 66% ± 4%, respectively, without mismatch (p = 0.08).

CONCLUSIONS

Severe mismatch adversely affected long-term survival for older patients receiving bioprosthetic valves. With mechanical valves, there was a trend toward impaired survival when mismatch was moderate or severe in younger patients. Thus, selection of an appropriate mitral prosthesis warrants careful consideration of age and valve type.

Hancock II bioprosthesis for aortic valve replacement: the gold standard of bioprosthetic valves durability?

BACKGROUND

This study examined the long-term durability of the Hancock II bioprosthesis (Medtronic, Minneapolis, MN) in the aortic position.

METHODS

From 1982 to 2004, 1134 patients underwent aortic valve replacement (AVR) with Hancock II bioprosthesis and were prospectively monitored. Mean patient age was 67 +/- 11 years; 202 patients were younger than 60, 402 were 60 to 70, and 526 were older than 70. Median follow-up was 12.2 years and 99.2% complete. Valve function was assessed in 94% of patients. Freedom from adverse events was estimated by the Kaplan-Meier method.

RESULTS

Survival at 20 and 25 years was 19.2% +/- 2% and 6.7% +/- 2.8%, respectively, with only 34 and 3 patients at risk. Survival at 20 years was 54.9% +/- 6.4% in patients younger than 60 years, 22.7% +/- 3.3% in those 60 to 70, and 2.4% +/- 1.9% in those older than 70 (p = 0.01). Structural valve deterioration developed in 67 patients aged younger than 60, in 18 patients aged 60 to 70, and in 2 patients older than 70. The freedom from structural valve deterioration at 20 years was 63.4% +/- 4.2% in the entire cohort, 29.2% +/- 5.7% in patients younger than 60 years, 85.2% +/- 3.7% in patients aged 60 to 70, and 99.8% +/- 0.2% in patients older than 70 (truncated at 18 years). Repeat AVR was performed in 104 patients (74 for structural valve failure, 16 for endocarditis, and 14 for other reasons). At 20 years, the overall freedom from AVR was 65.1% +/- 4% for any reason, 29.8% +/- 5.4% in patients younger than 60 years, 86.8% +/- 3.3% in patients 60 to 70, and 98.3% +/- 0.6% in patients older than 70.

CONCLUSIONS

Hancock II bioprosthesis is a very durable valve in patients 60 years and older and is probably the gold standard of bioprosthetic valve durability in this patient population.

Hemodynamic performance of the Medtronic Mosaic porcine bioprosthesis up to ten years

BACKGROUND

The Mosaic bioprosthesis (Medtronic, Minneapolis, MN) is a third-generation stented porcine bioprosthesis combining physiologic fixation and amino oleic acid antimineralization treatment to improve hemodynamic performance and durability. The findings of this single-center experience with this valve were evaluated to determine the clinical and hemodynamic performance.

METHODS

Between February 1994 and October 1999, we enrolled 255 patients with aortic valve replacement (AVR) with a mean age of 67 years (range, 23 to 82 years) and 47 patients with mitral valve replacement (MVR) with a mean age of 67 years (range, 41 to 84 years) in this post-United States Food and Drug Administration approval prospective and nonrandomized clinical trial. Patients were followed-up, including serial echocardiographic assessment, within 30 days, at 6 months, and annually thereafter. The cumulative follow-up was 1540 patient-years for AVR (mean, 6.1 years; maximum, 10 years) and 250 patient-years for MVR (mean, 5.4 years, maximum; 10 years).

RESULTS

Early mortality after AVR (<30 days) was 0.8%; late mortality per patient-year was 3.5%, including a valve-related/unexplained mortality of 1.1%. Early mortality after MVR (<30 days) was 0.0%; late mortality per patient-year was 2.8%, including a valve-related/unexplained mortality of 1.2%. Median postoperative gradient and effective orifice area for all valves after AVR were (early, n = 252; 5 years, n = 161; 9 years, n = 43) 13.7, 12.3, and 11.7 mm Hg and 1.9, 1.8, and 1.8 cm2 at early, 5 years, and 9 years, respectively. With MVR respective data were (early, n = 46; 5 years, n = 25; 7 years, n = 13) 4.6, 4.1, and 3.9 mm Hg and 1.8, 2.2, and 2.3 cm2. At 10 years, freedom from adverse events in the AVR group and MVR group was, respectively, thromboembolism, 86.6% +/- 6.6% and 86.3% +/- 9.8%; permanent neurologic event, 91.2% +/- 6.8% and 90.9% +/- 8.7%; valve thrombosis, 98.2% +/- 0.8% and 100%; structural valve deterioration, 87.1% +/- 6.7% and 100%.

CONCLUSIONS

Our midterm results demonstrate clinical safety and good performance of the Mosaic bioprosthesis. Continued follow-up will determine if this new design will provide increased durability.

Association between indices of prosthesis internal orifice size and operative mortality after isolated aortic valve replacement

OBJECTIVES

The appropriate index of prosthesis internal orifice size and its effect on operative mortality after aortic valve replacement are controversial. We examined the association between several relevant indices and patient size on operative mortality. Indices examined included projected in vivo effective orifice area and geometric orifice area, with patient size defined as body surface area.

METHODS

A review of the Society of Thoracic Surgeons National Cardiac Database (2000-2004) yielded 48,722 patients who had isolated aortic valve replacement. This analysis is based on the cohort of 42,310 patients with the 8 most prevalent valve types with manufacturer's labeled sizes 19 mm through 29 mm. Multivariable logistic regression models were employed to determine the effects of body surface area, effective orifice area, geometric orifice area, and selected derived indices (eg, effective orifice area/body surface area) on risk-adjusted operative mortality.

RESULTS

In separate multivariable models, effective orifice area and geometric orifice area were both inversely correlated with operative mortality. However, an unanticipated finding was that with either effective orifice area or geometric orifice area held constant, body surface area was significantly and inversely correlated with operative mortality. When patients were stratified by effective orifice area, geometric orifice area, or manufacturer's labeled valve size and type, elevations in body surface area were associated with a decrease rather than an increase in operative mortality.

CONCLUSIONS

Prostheses with small geometric orifice area or small effective orifice area are associated with increased operative mortality after isolated aortic valve replacement. Even for valves with small effective orifice area, however, mortality decreases as body surface area increases. With respect to operative mortality, therefore, our results do not support using arbitrary cutoff values of effective orifice area/body surface area to determine the valve to utilize in a given patient.

Clinical and hemodynamic implications of supra-annular implant of biological aortic valves

The use of stented bioprostheses in elderly patients with degenerative aortic stenosis, despite being desirable, raises concerns about the harmful effects of residual obstruction to left ventricular outflow. To overcome this limitation new stented and stentless bioprostheses have been designed for supra-annular implant. However, the actual hemodynamic advantage of supra-annular implant over the intra-annular one remains incompletely understood. This review focuses on the geometry of biological valve prostheses designed for supra-annular implant and its implications for the echocardiographic assessment of valve hemodynamics. Available data about the hemodynamic performance of these valves implanted in the supra-annular position in comparison with the usual intra-annular implant are also reviewed. Other issues related to biological heart valve performance, such as biomaterials, tissue mechanics, durability, and clinical outcome are not addressed in this review.

Prosthesis-Patient Mismatch After Aortic Valve Replacement: Impact of Age and Body Size on Late Survival

BACKGROUND

The purpose of this study was to identify patient subgroups in which prosthesis-patient mismatch most influenced late survival.

METHODS

Over a 12-year period, 1,400 consecutive patients underwent bioprosthetic (933 patients) or mechanical (467) aortic valve replacement. Prosthesis-patient mismatch was defined as prosthetic effective orifice area/body surface area less than 0.75 cm2/m2 and was present with 11% mechanical and 51% bioprosthetic valves.

RESULTS

With bioprosthetic valves, prosthesis-patient mismatch was associated with impaired survival for patients less than 60 years old (10-year: 68% +/- 7% mismatch versus 75% +/- 7% no mismatch, p < 0.02) but not older patients (p = 0.47). Similarly, with mechanical valves, prosthesis-patient mismatch was associated with impaired survival for patients less than 60 years old (10-year: 62% +/- 11% versus 79% +/- 4%, p < 0.005) but not older patients (p = 0.26). For small patients (body surface area less than 1.7 m2), prosthesis-patient mismatch did not impact survival with bioprosthetic (p = 0.32) or mechanical (p = 0.71) valves. For average-size patients (body surface area 1.7 to 2.1 m2), prosthesis-patient mismatch was associated with impaired survival with both bioprosthetic (p < 0.05) and mechanical (p < 0.005) valves. For large patients (body surface area greater than 2.1 m2), prosthesis-patient mismatch was associated with impaired survival with mechanical (p < 0.04) but not bioprosthetic (p = 0.40) valves.

CONCLUSIONS

Prosthesis-patient mismatch had a negative impact on survival for young patients, but its impact on older patients was minimal. In addition, although prosthesis-patient mismatch was not important in small patients, prosthesis-patient mismatch negatively impacted survival for average-size patients and for large patients with mechanical valves.

Long-term durability of the Hancock II porcine bioprosthesis

BACKGROUND

Survival and prosthetic complications of patients receiving the Hancock II second-generation bioprosthesis (Medtronic, Inc, Minneapolis, Minn) in the aortic, mitral, mitral-aortic, and tricuspid positions were analyzed at 15 years' follow-up.

METHODS

Between May 1983 and December 1993, 212 patients (104 men and 108 women; mean age, 63 +/- 9 years; age range, 29-81 years) received 66 aortic, 114 mitral, 26 mitral-aortic, and 6 tricuspid Hancock II valves. Thirty-one percent of patients had previous valve operations, 15% had concomitant cardiac procedures, and 87% were in New York Heart Association class III or IV. Follow-up included 1704 patient-years and was 98% complete, with a median of 9 patient-years (range, 0.013-17.4 years). Forty-six patients were at risk at 14 to 15 years, and 30 were at risk after 15 years.

RESULTS

One hundred twenty-two (57%) of 212 patients died, 20 of them perioperatively. Fifteen-year actuarial Kaplan-Meier survival was 35.2% +/- 3.8%, and freedom from valve-related mortality was 84% +/- 3.5%, with no difference on the basis of position or age (<65 or >or=65 years). Percentages for freedom from thromboembolism, anticoagulant-related hemorrhage, endocarditis, and paravalvular leak were, respectively, 78.2% +/- 4%, 83.5% +/- 3.6%, 95.7% +/- 2%, and 97.3% +/- 1.4%, with no significant difference between the aortic and mitral positions. Freedom from structural valve deterioration was 71.8% +/- 5.6%: 88.9% +/- 6.2% in the aortic position versus 59.5% +/- 3.9% in the mitral position (P =.01) and 64.3% +/- 3% in the mitral-aortic position. In patients younger than 65 years, actual freedom from structural valve deterioration was less than that seen in older patients (84.5% +/- 3.5% vs 95% +/- 3.0%) and was better in the aortic versus the mitral position (92% +/- 4.5% vs 82% +/- 4.2%).

CONCLUSION

The Hancock II porcine valve showed excellent 15-year durability. We recommend its use in patients 65 years of age, as well as in younger patients undergoing aortic replacement.

Hancock II bioprosthesis: a glance at the microscope in mid-long-term explants

BACKGROUND AND OBJECTIVES

The Hancock II bioprosthesis is a second-generation porcine valve xenograft treated with the detergent sodium dodecyl sulphate (T6) to retard calcification. The aim of this investigation was to study the gross and microscopic features in Hancock II explants to assess the structural changes occurring with time.

METHODS

Among 1382 Hancock II bioprostheses (701 isolated aortic, 421 isolated mitral, 130 double) implanted from 1983 to 1997 in 1252 patients, 22 (16 mitral, 6 aortic) were removed at reoperation until 1999 and were available for pathological investigation: infective endocarditis occurred in 5 and structural deterioration in 8, whereas in the remaining 9 xenografts reoperation was performed for nonstructural valve deterioration (paravalvular leak in 4 and prophylactic replacement in 5). Morphological investigation consisted of gross examination and x-ray, histologic, immunohistochemistry, electron microscopic, and atomic absorption spectroscopic examination.

RESULTS

The cause of structural valve deterioration was dystrophic calcification in 4 cases (1 aortic, 3 mitral; range of time graft was in place, 101 to 144 months), non-calcium-related tears in 3 cases (all mitral, range 121 to 163 months), and commissural dehiscence in 1 (aortic, range 156 months). Five of the nonstructural valve deterioration explants (range 42 to 122 months) showed only pinpoint mineralization at the commissures. Mean calcium content in nonstructural deterioration explants was 14.70 +/- 22.33 versus 99.11 +/- 81.52 mg/g in explants with structural valve deterioration. Electron microscopic examination showed early nuclei of mineralization mostly consisting of calcospherulae upon cell debris. Local or diffuse lipid insudation was observed in all but 2 explants and consisted of cholesterol clefts, lipid droplets, and lipid-laden macrophages featuring foam cells. The lipid insudation was the most plausible cause of tearing in 2 explants.

CONCLUSIONS

These pathologic findings support the clinical results of a delayed occurrence of structural failure of Hancock II bioprostheses and a mitigation of mineralization by the anti-calcification treatment. However, other factors such as lipid insudation may come into play in the long term.

Late hemodynamic and clinical outcomes of aortic valve replacement with the Carpentier-Edwards Perimount pericardial bioprosthesis

OBJECTIVES

The aim of this study was to investigate the long-term clinical and hemodynamic outcomes after aortic valve replacement with the Carpentier-Edwards Perimount bioprosthesis (Edwards Lifesciences, Irvine, Calif), which has been used in our institution since 1984.

METHODS

From January 1984 to December 1995, the Carpentier-Edwards pericardial bioprosthesis was used for aortic valve replacement in 254 patients (male/female ratio 117:137) with a mean age of 71 years (range 25-87 years). Before the operation, 216 patients (85%) were in New York Heart Association functional class III or IV. The predominant diagnosis was aortic stenosis (n = 219, 86%). Associated surgical procedures included coronary artery bypass grafting in 130 cases (51%), mitral valve replacement in 11 cases (4%), and tricuspid or mitral valve repair in 12 cases (5%). Previous cardiac operations had been performed in 36 cases (14%). Follow-up was 100% complete at a mean of 60 +/- 31 months. Univariate estimates of time-related cumulative probabilities were calculated by the Kaplan-Meier method. Multivariable adjustment was performed by Cox proportional hazards regression. Echocardiography was performed in 61% of long-term survivors.

RESULTS

There were 11 early deaths (4%) and 58 late deaths. Actuarial survivals at 5, 10, and 12 years were 80% +/- 3%, 50% +/- 8%, and 36% +/- 9%, respectively. At 12 years the freedom from cardiac death was 73% +/- 7%, the freedom from valve-related death was 84% +/- 11%, the freedom from valve reoperation was 83% +/- 9%, the freedom from primary tissue failure was 86% +/- 9%, the freedom from thromboembolism was 67% +/- 13%, and the freedom from endocarditis was 98% +/- 1%. Echocardiography was performed on long-term survivors (mean follow-up 67 +/- 25 months) and showed that transvalvular peak and mean pressure differences measured with Doppler echocardiography were 23.2 +/- 9.6 and 12.3 +/- 4.8 mm Hg, respectively. Aortic regurgitation was found by Doppler echocardiography to be none or trivial, mild, moderate, and severe in 64%, 30%, 3%, and 1% of patients, respectively. Mean left ventricular mass index was 107.2 +/- 35.3 g/m(2) (118.9 +/- 40.2 g/m(2) in men and 98.8 +/- 28.8 g/m(2) in women) at late follow-up. One third of all patients, regardless of sex (n = 26/64 women and n = 14/45 men), had evidence of left ventricular hypertrophy. However, our analyses indicate that the residual left ventricular hypertrophy was not caused by valve mismatch but was probably multifactorial.

CONCLUSION

The Carpentier-Edwards Perimount bioprosthesis has provided satisfactory clinical and hemodynamic outcome. However, at long-term follow-up about one third of the patients being investigated still had left ventricular hypertrophy examined by echocardiography.

Hemodynamic stability during 17 years of the Carpentier-Edwards aortic pericardial bioprosthesis

BACKGROUND

Long-term stability of the hemodynamic performance of commercially available Carpentier-Edwards stented bovine pericardial aortic bioprostheses (Perimount RSR) is unknown. To anticipate the fate of this bioprosthesis, we examined its hemodynamic performance up to 17 years using echocardiographic studies in a Premarket Approval cohort.

METHODS

Of 267 patients at four institutions in the Premarket Approval cohort, 85 had a total of 168 echocardiographic studies during a 17-year period of yearly follow-up examinations. These were reviewed and quantified in a core echocardiographic facility. Longitudinal data analysis was used to account for repeated, censored data.

RESULTS

Mean transvalvular gradient was inversely related to prosthesis size (p = 0.01), and possibly (p = 0.06) increased somewhat during the first 10 years of follow-up, then stabilized. Effective orifice area was larger in larger valve sizes (p = 0.01), declined somewhat during the first 10 years, and then began to increase again. Ejection fraction declined minimally (p = 0.2). In contrast to the rather stable hemodynamics, aortic regurgitation steadily increased from none to 1 to 2+ (p = 0.005), but rarely (< 10% at 17 years) progressed to 3+ or 4+.

CONCLUSIONS

The Carpentier-Edwards aortic pericardial bioprosthesis can be anticipated to have an acceptable long-term transvalvular gradient and effective orifice size that will change trivially up to 17 years after implantation. Mild aortic regurgitation will develop progressively. This anticipated hemodynamic resilience supports continued clinical use of the Perimount Carpentier-Edwards bovine pericardial stented bioprosthesis.

Mosaic valve international clinical trial: early performance results

BACKGROUND

A new third generation porcine bioprosthesis was developed in an attempt to improve on hemodynamic performance and durability of current prostheses.

METHODS

One thousand, two hundred, sixty patients underwent aortic valve replacement and 366 patients underwent mitral valve replacement between February 1994 and September 2000. The cumulative follow-up was 3,696.3 patient-years for aortic valve replacement and 880.1 patient-years for mitral valve replacement. Follow-up was complete for 95.5% of aortic valve replacement patients and 97.5% of mitral valve replacement patients.

RESULTS

For aortic valve replacement, freedom from valve-related adverse events at 1 year was 96.5%+/-0.5% for antithromboembolic-related hemorrhage and 100% for structural valve deterioration. Freedom from valve-related adverse events at 5 years was 93.8%+/-2.6% for antithromboembolic-related hemorrhage and 99.3%+/-0.9% for structural valve deterioration. For mitral valve replacement, freedom from valve-related adverse events at 1 year was 96.0%+/-1.1% for antithromboembolic-related hemorrhage and 100% for structural valve deterioration. Freedom from valve-related adverse events at 4 years was 92.1%+/-3.7% for antithromboembolic-related hemorrhage and 100% for structural valve deterioration.

CONCLUSIONS

These results support the claim that the Mosaic bioprosthetic valve is efficacious and safe, but continued follow-up is mandatory to determine mid- and long-term performance.

Are the indications for tissue valves different in 2001 and how do we communicate these changes to our cardiology colleagues?

The indications for tissue valves in the aortic and mitral positions are becoming better defined with advances in valve design, valve preservation, and management of reoperations. Although some patients who require cardiac valve replacement clearly benefit more from one type of valve than from another, not infrequently one encounters a patient who is in the "gray zone," where the optimal choice is difficult. At present, bioprostheses for the diseased aortic valve include stented porcine and pericardial valves, stentless porcine valves, aortic homograft, and pulmonary autograft. For patients with mitral valve disease, options for tissue valve replacement are a stented porcine or pericardial prosthesis. Generally, factors to consider in choosing the appropriate valve substitute include the patient's age, expected life expectancy, coexisting medical problems, lifestyle, and socioeconomics; the etiology of the valve disease, annular size, and physician and patient preference are also relevant. Despite the known finite durability of tissue valves, which is the main limitation in their use, the long-term results have been satisfactory, particularly in older patients, patients with a limited life expectancy, and those undergoing valve replacement in the aortic position. Distillation of available information and ongoing communication between the surgeon and the cardiologist will enable us to assist the patient in choosing the best valve substitute.

Late results of heart valve replacement with the Hancock II bioprosthesis

OBJECTIVE

To review the late clinical outcomes of patients who had isolated aortic or mitral valve replacement with the Hancock II bioprosthesis.

METHODS

From 1982 to 1994, 670 patients underwent isolated aortic valve replacement and 310 underwent isolated mitral valve replacement with the Hancock II bioprosthesis (Medtronic Inc, Minneapolis, Minn). Mean age was 65 +/- 12 years in both groups. Most patients were in New York Heart Association functional classes III or IV, and concomitant coronary artery disease was present in 44% of patients in the aortic valve group and 41% of patients in the mitral valve group. Patients were followed up prospectively at periodic intervals. Mean follow-up was 87 +/- 45 months in the aortic valve group and 83 +/- 50 months in the mitral valve group, and it was 99% complete.

RESULTS

Actuarial survival at 15 years was 47% +/- 3% in the aortic valve group and 30% +/- 5% in the mitral valve group. Older age, advanced functional class, impaired left ventricular function, active endocarditis, and coronary artery disease were independent predictors of late death. The freedom from thromboembolic complications at 15 years was 83% +/- 3% in the aortic and 87% +/- 3% in the mitral valve group. The freedom from infective endocarditis at 15 years was 96% +/- 1% in the aortic and 91% +/- 1% in the mitral valve group. At 15 years, the actuarial and actual freedom from structural valve deterioration was 81% +/- 5% and 90% +/- 3%, respectively, in the aortic group and 66% +/- 6% and 83% +/- 3%, respectively, in the mitral group. Younger age, mitral valve position, and poor ventricular function were independent predictors of structural valve deterioration. The freedom from repeat valve replacement at 15 years was 77% +/- 5% in the aortic group and 69% +/- 6% in the mitral. The vast majority of patients had functional improvement after valve replacement.

CONCLUSIONS

The Hancock II bioprosthesis has provided good clinical outcomes and is a durable valve, particularly in the aortic position in older patients.

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

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

Early experience with the mosaic bioprosthesis: a new generation porcine valve

BACKGROUND

The Mosaic bioprosthesis is a new generation stented porcine valve.

METHODS

Between May 1995 and April 1998, this valve was implanted in the aortic position in 98 patients (70 men; mean age, 69.2 years [34.2 to 83.6 years]). Preoperatively 35 patients were in New York Heart Association functional class 3 or 4. Fifty-nine patients underwent concomitant procedures. The mean duration at follow-up in January 1999 was 23.7 +/- 10.2 months (0.3 to 39.4 months) and totaled 193 patient-years. All but one survivor was in New York Heart Association class 1 or 2.

RESULTS

Early complications included 1 death, 3 reoperations for bleeding, greater than mild regurgitation (paravalvar) in 1 patient and thromboembolism in 4 patients. Late complications included four deaths, study-valve endocarditis in 3 patients, more than mild regurgitation or hemolysis in 2, and thromboembolism in 2 patients. Late follow-up echocardiography in all survivors showed a mean transaortic gradient of 13.6 +/- 6.7 mm Hg, and an aortic valve area of 1.80 +/- 0.61 cm2. Valve replacement was followed by a significant and sustained decrease in left ventricular mass for all valve sizes. There has been no primary structural valve failure.

CONCLUSIONS

The early experience with the Mosaic valve in the aortic position has been promising.

Early experience of aortic valve replacement with the Freestyle stentless aortic bioprosthesis in elderly patients

OBJECTIVES

Stentless bioprostheses have been gaining popularity in recent years as hemodynamically superior alternatives to conventional stented bioprostheses.

METHODS

Between July 1996 and November 1998, 13 patients with aortic valve disease, 7 males and 6 females with a mean age (+/- SD) of 68 +/- 5 years, underwent an aortic valve replacement using the Medtronic Freestyle aortic bioprosthesis. The predominant lesions were stenosis in 8 patients and regurgitation in 5, while 2 patients had endocarditis. The operation was performed by a subcoronary technique in 9, root-inclusion technique in 3, and full root technique in 1 patient.

RESULTS

Throughout the follow-up periods (with average follow-up period of 20.6 months), there was no hospital mortality, though there was one late death of unknown cause. The New York Heart Association class improved in all patients. The peak transvalvular gradient decreased from 18.4 +/- 9.8 to 12.6 +/- 9.6 mmHg, and the effective valve orifice area increased from 2.30 +/- 0.96 to 2.59 +/- 1.05 cm2 between the 1-month and the 6-month follow-up examinations. In patients with aortic regurgitation, the left ventricular end-diastolic/end-systolic volume index significantly decreased from 147 +/- 36/62 +/- 19 to 73 +/- 26/33 +/- 14 ml/m2 at 1 month after the operation. The left ventricular mass index also significantly decreased from 189 +/- 26 to 143 +/- 30 g/m2 in patients with aortic regurgitation and from 171 +/- 28 to 144 +/- 30 g/m2 in those with aortic stenosis.

CONCLUSIONS

Although long-term follow-up is required for further evaluation, the early results appeared to indicate that the Freestyle aortic bioprosthesis was suitable for elderly patients requiring aortic valve replacement.

The impact of age, coronary artery disease, and cardiac comorbidity on late survival after bioprosthetic aortic valve replacement

OBJECTIVES

This study was designed to determine the effects of age, coronary artery disease and other cardiac comorbidities on late outcome following bioprosthetic aortic valve replacement.

METHODS

Data were prospectively collected on 670 patients undergoing aortic valve replacement with the Hancock II bioprosthesis (Medtronic, Inc, Minneapolis, Minn) between 1982 and 1994. Mean patient age was 65 +/- 12 years (median, 68 years; range, 18-86 years). Follow-up was 99.7% complete at 69 +/- 40 months (median, 66 months; range, 0. 1-168 months). Survival and freedom from reoperation were evaluated univariately by Kaplan-Meier analysis and multivariably by Cox regression.

RESULTS

After adjustment for gender, Cox regression analysis revealed that age of 65 years or older, left ventricular dysfunction, the presence of coronary artery disease, and advanced New York Heart Association functional classification were associated with a higher risk of late death. At 12 years, survival was significantly different by Kaplan-Meier analysis for both age younger than 65 years (71% +/- 4%) versus age 65 years or older (36% +/- 7%; P <.0001), left ventricular function grades 3 and 4 (26% +/- 13%) versus grades 1 and 2 (59% +/- 4%; P <.0001), no coronary artery disease (65% +/- 4%) versus coronary artery disease (35% +/- 8%; P <.0001), and functional class IV (33% +/- 9%) versus classes I to III (62% +/- 4%; P <.0001). Only 9 patients experienced primary tissue failure, all of whom were younger than 65 years of age. At 12 years, the freedom from primary tissue failure was 84% +/- 4% for those patients younger than 65 years of age, and 100% for those 65 years of age or older (P =.006).

CONCLUSIONS

Long-term survival after aortic valve replacement is highly dependent on age, coronary artery disease, functional class, and left ventricular function, although bioprosthetic durability is dependent almost solely on age. Due to increased valve durability in patients who are 65 years of age or older, the Hancock II bioprosthesis may be an ideal aortic valve substitute in this age group. In patients who are younger than 65 years of age with advanced functional class, impaired left ventricular function, and coronary artery disease, this valve may also be used with a low probability of primary tissue failure. Patients without additional cardiac comorbidity may outlive their bioprosthetic valve, leading to reoperation.

The Hancock II bioprosthesis at 12 years

BACKGROUND

The Hancock II bioprosthesis has been used for heart valve replacement since 1982 in our institution. We previously reported its clinical performance at 8 years and at 10 years. This is a progress report on its performance at 12 years.

METHODS

From 1982 to 1994 the Hancock II bioprosthesis was used for aortic valve replacement (AVR) in 723 patients and for mitral valve replacement (MVR) in 328 patients. The mean age of the patients was 65 years for both groups. Coronary artery disease was present in 42% of patients who had AVR and 45% of patients who had MVR. Patients have been followed up prospectively at annual intervals; the mean follow-up was 68+/-40 months for AVR and 66+/-43 months for MVR; it was 99% complete.

RESULTS

There were 36 (5%) operative and 159 late deaths in the AVR group, and 26 (8%) operative and 92 late deaths in the MVR. The actuarial survival at 12 years was 54%+/-4% for AVR and 42%+/-5% for MVR. Age greater than 65 years and coronary artery disease had a profound effect on late survival. At 12 years the freedom from thromboembolism was 86%+/-2% for AVR and 90% +/-2% for MVR; from endocarditis, 95%+/-1% for both groups; from primary tissue failure, 94%+/-2% for AVR and 82%+/-5% for MVR; and from valve reoperation, 89% +/-3% for AVR and 78%+/-5% for MVR. There was no primary tissue failure at 12 years in patients older than 65 years who had AVR.

CONCLUSIONS

The clinical performance of the Hancock II has been very satisfactory and this bioprosthesis appears to be more durable than its predecessors.

Aortic valve replacement with patch enlargement of the aortic annulus

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Left ventricular mass regression early after aortic valve replacement

BACKGROUND

Regression of left ventricular hypertrophy is an important and well-recognized salutary effect of aortic valve replacement. The earliest evidence of left ventricular mass regression after aortic valve replacement and the influence of prosthesis type are not well known, and were the focus of this study.

METHODS

Transthoracic echocardiography was used to measure left ventricular mass index preoperatively and before discharge in 57 consecutive patients undergoing isolated aortic valve replacement (with or without coronary artery bypass grafting).

RESULTS

Three patients were excluded from the study because of inability to obtain accurate M-mode echocardiographic images for left ventricular mass measurement preoperatively (1) or postoperatively (2). Of the remaining 54 patients, mechanical bileaflet valves were used in 19, stented tissue bioprostheses were implanted in 15, and a stentless porcine bioprosthesis was chosen for 20. Postoperative echocardiograms were obtained 4.9 +/- 2.3 days after aortic valve replacement (range, 2 to 9 days). A two-way repeated-measures analysis of variance demonstrated a significant reduction of left ventricular mass index before discharge (preoperative 141.4 +/- 45.2 g/m2, postoperative 127.5 +/- 32.8 g/m2; p = 0.0005) but no differences between prostheses.

CONCLUSIONS

Left ventricular mass regression begins early after aortic valve replacement, probably because of reduction of transvalvular gradients and left ventricular wall stress. At least in the very early postoperative period, the type of prosthesis does not influence the extent of mass regression.

Carpentier-Edwards standard porcine bioprosthesis: clinical performance to seventeen years

BACKGROUND

The role of porcine bioprostheses in cardiac valve replacement has been under review for several years. The literature deals primarily with age as a determinant of durability, as well as the intermediate-term performance of various prostheses. The performance of the Carpentier-Edwards first-generation standard porcine bioprosthesis is presented over the long-term with further documentation on age determinants.

METHODS

The "Guidelines for Reporting Morbidity and Mortality After Cardiac Valvular Operations" were used for definitions of valve-related complications, categorization, and statistical methods. The valve-related complications were evaluated in a time-related manner by actuarial life-table techniques. The Lee-Desu statistic test was used for comparison of performance by valve positions and age groups. Hazard function rates were demonstrated for complications and composites.

RESULTS

Of the Carpentier-Edwards porcine bioprostheses implanted in 1,195 patients (1,214 operations, 1,315 valves) commencing in 1975 the early mortality was 7.6% (92). The early mortality without concomitant procedures was 6.1% and with 11.7%. The late mortality was 5.3% per patient-year; 4.6% patient-year without and 7.5% per patient-year with concomitant procedures. The valve-related causes of late mortality (131) were thromboembolism (41), antithromboembolic hemorrhage (14), prosthetic valve endocarditis (20), nonstructural dysfunction (12), and structural valve deterioration (44). The valve-related deaths (early, 7; late, 124) were 21.2% of the total 617 total deaths. Reoperation for valve-related complications was performed in 406 patients (4.1% per patient-year), of which 327 were for structural valve deterioration (3.3% per patient-year). Mortality for reoperation was 0.5% per patient-year (49 patients) or 12.1%. Of the 49 deaths, 33 were caused by structural valve deterioration. The linearized occurrence rate for thromboembolism was 1.6% per patient-year (major, 0.9% per patient-year, and minor, 0.7% per patient-year). The fatal thromboembolic rate was 0.4% per patient-year (41), undifferentiated by valve position. The freedom from thromboembolism was 76% at 17 years (p = not significant by valve position) (major, 87%; fatal, 93%). The freedom from prosthetic valve endocarditis was 92% at 17 years (p = not significant by valve position). The freedom from reoperation, at 15 years, was 38%: aortic (AVR), 55%; mitral (MVR), 20%; and multiple valve replacement (MR), 24% (p < 0.05 AVR > MVR, MR). The freedom from structural valve deterioration, at 15 years, was 41%; AVR, 58%; MVR, 21%; MR, 36% (p < 0.05 AVR > MVR, MR). The freedom from structural valve deterioration was greater for advancing age groups (p < 0.05); AVR > or = 70 years 96% at 12 years, and 65 to 69 years 94% at 12 years and 82% at 15 years; MVR > or = 70 years 85% at 12 years, and 65 to 69 years 54% at 12 years. The freedom from valve-related mortality was 73% at 17 years: AVR, 80%; ; MVR, 61%; and MR, 67% (p < 0.05 AVR > MVR, MR). The freedom valve-related residual morbidity was 94% (p = not significant by valve position).

CONCLUSIONS

The Carpentier-Edwards standard porcine bioprosthesis continues to provide satisfactory clinical performance to 17 years. Thromboembolism is a more serious problem than structural failure: 92 major thromboembolic events with 41 fatalities compared with 44 fatalities of which 33 occurred with reoperation. The prosthesis is especially recommended for patients more than 65 years of age for AVR and more than 70 years of age for MVR.

The Hancock II bioprosthesis at ten years

The Hancock II bioprosthesis was used for heart valve replacement in 843 patients from 1982 to 1993. Aortic valve replacement (AVR) was performed in 536 patients, mitral valve replacement (MVR) in 250, and aortic and mitral valve replacement (DVR) in 57. The mean age was 64 +/- 12 years. Before operation, 80% of the patients were in New York Heart Association functional class III or IV; approximately one-third of the patients had coronary artery disease, and 60 patients had ascending aorta aneurysm. There were 47 operative deaths (AVR, 4%; MVR, 7%; DVR, 10%) and 147 late deaths. Follow-up was complete in 98.6% of the patients and extended from 3 to 140 months (mean, 59 months). At the last follow-up, 84% of the patients were in New York Heart Association class I or II. The actuarial survival at 10 years was 63% +/- 4% for AVR, 55% +/- 5% for MVR, and 53% +/- 9% for DVR. At the end of 10 years, the freedom from thromboembolic complications was 80% +/- 4% for AVR, 88% +/- 3% for MVR, and 86% +/- 5% for DVR; the freedom from endocarditis was 95% +/- 2% for AVR, 96% +/- 1% for MVR, and 87% +/- 5% for DVR; the freedom from primary tissue failure was 92% +/- 3% for AVR, 81% +/- 6% for MVR, and 65% +/- 16% for DVR; and the freedom from reoperation was 89% +/- 2% for AVR, 81% +/- 6% for MVR, and 61% +/- 15% for DVR. The durability of this bioprosthetic valve was affected by the patient's age and by the position where it was implanted. The clinical results of the Hancock II bioprosthesis at 10 years are comparable to those of other current porcine and pericardial valves.

Comparison of low-pressure versus standard-pressure fixation Carpentier-Edwards bioprosthesis

Intermediate-phase clinical results of 51 low-pressure (LP) and 234 standard-pressure (SP) fixation porcine Carpentier-Edwards (CE) valves implanted between 1977 and 1991 were compared for valve-related events. Group similarities included New York Heart Association functional class, ejection fraction, and sex. Patients with SP valves were younger (mean age, 58 versus 68 years; p = 0.0001). There were 20 in-hospital deaths (8.6%) in the SP valve group and 5 (9.8%) in the LP valve group (p = 0.79). Follow-up was 99%, with a mean of 104 months in the SP valve group versus 55 months in the SP valve group (p = 0.0001). The actuarial survival rate was 48.2% and 22.3% at 10 and 15 years, respectively, in the SP valve group and 34.1% at 10 years in the LP valve group (p = 0.42). Freedom from events at 5, 10, and 15 years in the SP valve group and at 5 years in the LP valve group was as follows: for late valve-related events, 86.3%, 51.4% and 20.2%, respectively, in the SP valve group versus 85% in the LP valve group (p = 0.44); for valve-related death, 96.4%, 93.6%, and 87.3% in the SP valve group versus 100% in the LP valve group (p = 0.20); for structural valve failure, 96%, 68%, and 35% in the SP valve group versus 100% in the LP valve group (p = 0.09); and for reoperation, 95%, 61%, and 30% in the SP valve group versus 92% in the LP valve group (p = 0.82). In conclusion, this study revealed no significant statistical difference between LP and SP valves. In the LP valve group, structural valve failure/valve-related death was not observed, perhaps indicating a more favorable result. Absolute verification of this trend awaits long-term follow-up.

Porcine valve durability: a comparison between Hancock standard and Hancock II bioprostheses

Two series of patients who received a Hancock standard (HS) (1970 to 1983) and a Hancock II (HII) (1983 to 1992) porcine bioprosthesis were reviewed to compare bioprosthetic durability. Patients with HS porcine bioprostheses (n = 769) differed from those with HII bioprostheses mostly in mean age at operation (47 +/- 12 versus 62 +/- 9 years; p < 0.001); the latter prosthesis was implanted mostly in patients older than 50 years. At 8 years after operation, actuarial survival was 57% +/- 4% after aortic, 61% +/- 3% after mitral, and 39% +/- 7% after mitral-aortic valve replacement with the HS bioprosthesis; actuarial survival was 51% +/- 9% after aortic, 66% +/- 6% after mitral, and 49% +/- 10% after mitral and aortic valve replacement with an HII bioprosthesis. No cases of structural deterioration of HII bioprostheses were observed at 8 years in any patients. Actuarial freedom from structural valve deterioration was 78% +/- 4% after aortic, 88% +/- 3% after mitral, and 79% +/- 7% after mitral-aortic valve replacement with an HS bioprosthesis at 8 years. In all patients greater than 50 years of age, actuarial freedom from structural valve deterioration at 8 years was 90% +/- 3% in patients with an HS bioprosthesis and 100% in those with an HII bioprosthesis (p = 0.08). A trend to an improved durability of the HII bioprosthesis compared with the HS was observed during the first 8 postoperative years. Because these results could be influenced partly by the age difference in the two series of patients, a longer follow-up is needed to confirm these data.

Carpentier-Edwards supraannular porcine bioprosthesis: clinical performance to twelve years

The Carpentier-Edwards supraannular porcine bioprosthesis, a second-generation biologic prosthesis, has had clinical performance assessment to 12 years. This bioprosthesis was used in 2,489 operations in 2,444 patients between 1982 and 1992, inclusive (mean age 64.1 years, age range 6 to 89 years). There were 1,335 aortic valve replacements (AVR), 938 mitral valve replacements (MVR), and 200 multiple valve replacements (MR). Concomitant procedures were performed in 1,017 cases (40.9%). The age group distribution was: 35 years or younger, 83 patients; 36 to 50 years, 245; 51 to 64 years, 728; 65 to 69 years, 458; and 70 years and older, 975. The total follow-up was 12,785 patient-years (mean, 5.1 years) and was 96% complete. The early mortality rate was 7.4% (185 patients), and the late mortality was 4.9%/patient year (623). Concomitant procedures influenced both early and late mortality (p < 0.05). The overall patient survival at 12 years was 44% +/- 3% (p < 0.05, AVR > MVR, MR). The freedom from thromboembolism was not different by valve position. The freedom from major thromboembolism at 12 years was 82% +/- 4% (p = not significant by valve position). The overall freedom from antithromboembolic hemorrhage was 96% +/- 1% at 12 years (p < 0.05, AVR > MVR > MR). The overall freedom from valve-related reoperation at 12 years was 58% +/- 5% (p < 0.05, AVR > MVR, MR), and from valve-related mortality 89% +/- 2% (p < 0.05, AVR > MVR > MR). The freedom from residual morbidity (permanent impairment) at 12 years was 87% +/- 4% (p = not significant by valve position).(ABSTRACT TRUNCATED AT 250 WORDS)

Structural deterioration in Carpentier-Edwards standard and supraannular porcine bioprostheses

The Carpentier-Edwards standard (CE-S) porcine bioprosthesis was implanted in 1214 operations (1975 to 1985) and the Carpentier-Edwards supraannular (CE-SAV) bioprosthesis was implanted in 2,489 operations (1982 to 1992 inclusive). The early mortality was 7.6% and 7.4% for the CE-S and CE-SAV groups, respectively; the late mortality was 5.3% per patient-year and 4.9% per patient-year, respectively. The cumulative follow-up was 9,968 patient-years for the CE-S group and 12,784 patient-years for the CE-SAV group. Concomitant procedures were performed in 26.8% of the patients who received a CE-S and in 40.9% of those who received a CE-SAV (p < 0.05). The mean age of the patients receiving a CE-S was 57.3 years (range, 8 to 85 years) and was 64.1 years (range, 6 to 89 years) in those receiving a CE-SAV. The CE-S group consisted of 578 atrial valve replacements (AVRs), 512 mitral valve replacements (MVRs), and 115 multiple valve replacements (MRs). The CE-SAV group consisted of 1,335 AVRs, 938 MVRs, and 200 MRs. There was a total of 165 cases of structural valve deterioration (SDV) in the CE-SAV group (AVR, 35; MVR, 98; and MR, 32). The effect of trimming the aortic wall was also considered: 20 of the 931 trimmed prostheses used for MVRs and MRs and none of the 207 reduced-trimmed prostheses exhibited SVD. The cumulative follow-up was 5,422 years for the patients with trimmed prostheses and 470 for those with reduced-trimmed prostheses.(ABSTRACT TRUNCATED AT 250 WORDS)

Medtronic Intact porcine bioprosthesis: clinical performance to seven years

The clinical performance of the Medtronic Intact porcine bioprosthesis was evaluated in 1,084 patients (mean age 66.4 years, range 9 to 91 years) who had a total of 1,099 implantations between 1985 and 1992, inclusive. There were 709 aortic valve replacements, 297 mitral valve replacements, and 80 multiple valve replacements. Concomitant procedures were performed in 432 (39.3%). The age group distribution (years) was 35 or younger in 20 patients, 36 to 50 in 64, 51 to 64 in 274, 65 to 69 in 225, 70 or older in 500. The total follow-up time was 2,741 patient-years (mean, 2.5 years) and was 97.5% complete. The early mortality rate was 7.1% and late mortality was 3.9% per patient-year. The overall patient survival at 7 years was 70% +/- 3%. The freedom from major thromboembolism was 94% +/- 1% at 7 years (p = not significant for valve positions). The freedom from reoperation at 7 years was 93% +/- 1%; freedom from valve-related mortality was 89% +/- 2%. The freedom from structural valve deterioration at 7 years was 97% +/- 1% (aortic valve replacement 97% +/- 1%; mitral valve replacement 97% +/- 2%). The freedom from structural valve deterioration among age groups was not different for the overall population, aortic valve replacement, or mitral valve replacement. Hemodynamic assessment revealed obstructive properties for aortic valve replacement sizes of 21 and 23 mm and for mitral valve replacement sizes of 25 and 27 mm.(ABSTRACT TRUNCATED AT 250 WORDS)

Stentless porcine aortic root: valve of choice for the elderly patient with small aortic root?

The Medtronic Freestyle bioprosthesis is a stentless porcine aortic root cross-linked in dilute glutaraldehyde solution with stress-free fixation for the valve leaflets. It has been treated by a process in which amino oleic acid is used to reduce the potential for calcification. As a complete aortic root, it has the same versatility as the aortic homograft but has the advantage that it is readily available in all sizes to the implanting surgeon. Between January 1993 and May 1994, we implanted 64 Freestyle bioprostheses as aortic valve replacements using a freehand technique; 5 size 19 mm, 15 size 21 mm, 16 size 23 mm, 13 size 25 mm, and 15 size 27 mm valves were used. There were 35 men and the mean age was 75.7 years (64 to 84 years). The operative mortality was 3.1% (2/64). Echocardiograms at the time of discharge revealed mean aortic valve gradients ranging from 18.2 mm Hg for 19 mm to 10.3 mm Hg for 27 mm valves. Effective orifice areas ranged from 1.0 cm2 for 19 mm to 2.0 cm2 for 27 mm valves. No patient had more than trace aortic insufficiency. Our early experience with this new stentless bioprosthesis shows it to have excellent hemodynamics especially in the smaller valve sizes. Using this valve in patients who have a small aortic root and require a tissue valve avoids the need for aortic root enlargement procedures.

Hancock II porcine bioprosthesis: excellent durability at intermediate-term follow-up

OBJECTIVES

This study aimed to assess the clinical performance and durability of a new generation of porcine valve, the Hancock II bioprosthesis, at intermediate-term follow-up.

BACKGROUND

Standard porcine bioprostheses undergo progressive structural deterioration, mainly due to cusp and commissural calcification, affecting durability and requiring reoperation. The Hancock II bioprosthesis, which is currently undergoing clinical investigation, is made from a porcine aortic valve treated with a calcium-retarding agent (sodium dodecyl sulfate [T6]), which should delay onset of calcification and increase durability.

METHODS

From May 1983 to December 1992, we used the Hancock II bioprothesis in aortic (59 patients), mitral (101 patients) and mitral-aortic (25 patients), valve replacement procedures. Postoperative follow-up ranged from 0.1 to 8.7 years (mean [+/- SD] 4.5 +/- 2.6 years) and was 100% complete. Freedom from major postoperative events was calculated at 7 years for patients with aortic valve replacement and at 8 years for those with mitral and mitral-aortic valve replacement.

RESULTS

The actuarial survival rate was 48 +/- 10%, 76 +/- 3% and 63 +/- 6%; freedom from valve-related mortality was 91 +/- 4%, 94 +/- 2% and 89 +/- 6%; freedom from thromboembolism was 80 +/- 11%, 90 +/- 2% and 79 +/- 7%; and freedom from reoperation was 100%, 97 +/- 1% and 89 +/- 6% after aortic, mitral and mitral-aortic valve replacement, respectively. No structural valve deterioration occurred.

CONCLUSIONS

At intermediate-term follow-up the Hancock II bioprosthesis showed excellent durability in all positions. However, the effectiveness of anticalcification treatment must be assessed with longer follow-up studies.

What is the best bioprosthetic operation for the small aortic root?: allograft, autograft, porcine, pericardial? Stented or unstented?

Durability is assessed with regard to valve position, patient age, and the techniques of graft preparation for each of the tissue valves. Design affects both durability and the effective orifice area. It is assessed for each of the available devices, with particular emphasis on the stentless porcine valve. The effect that differences between this glutaraldehyde fixed device and the allograft valve may have on techniques of implantation is analyzed. On the basis of this information, an attempt is made to grade the currently available tissue valves with a satisfactory intermediate-term performance for use in the small aortic root.

Modern cardiac valve devices--bioprostheses and mechanical prostheses: state of the art

The choice of bioprostheses and mechanical prostheses as valvular substitutes for cardiac valve replacement surgery has existed for over 20 years. The extensive developments over the past three decades have been introduced to reduce or eliminate valve related complications, namely thromboembolism, anticoagulant related hemorrhage, and structural failure, as well as to optimize hemodynamic performance. The biological valvular prostheses, namely porcine aortic or bovine pericardium, have been developed with tissue preservation, together with stent designs, that contribute to preservation of anatomical characteristics and biomechanical properties of the leaflets. The mechanical prostheses have been developed to eliminate structural failure, to facilitate prevention of blood status and thrombus formation, to facilitate radiopacity for evaluation of prosthesis function, and to facilitate intraoperative leaflet positioning. The implantation of the various present generation bioprostheses and mechanical prostheses requires special considerations to avoid technical complications and support ventricular performance. The studies of biological and mechanical prostheses, both randomized and nonrandomized, as well as specific prosthesis assessments, have contributed to the establishment of indications for types of prostheses. Bioprostheses have a high risk of structural failure and reoperation, while mechanical prostheses have a high risk of thromboembolism and anticoagulant hemorrhage. Within the bioprostheses population, the risk factors for structural valve deterioration are younger age and mitral prosthesis. Older patients (> 65 years of age) have a greater risk of valve related complications with mechanical prostheses, while younger patients (< 40 years of age) are at greater risk with bioprostheses. Comparison of large bioprostheses and mechanical prostheses populations by age groups revealed that regardless of the differences in the freedom from structural valve deterioration, the freedom from treatment failure (valve related mortality and permanent impairment from thromboembolism, anticoagulant hemorrhage, and septal emboli from prosthetic valve endocarditis) is essentially the same for mechanical prostheses and bioprostheses at 10 years. The quality of life is superior with bioprostheses, while patient survival and total valve related morbidity/mortality are similar with both types of prostheses.