Rest and exercise hemodynamics following aortic valve replacement. A comparison between 19 and 21 mm Ionescu-Shiley pericardial and Carpentier-Edwards porcine valves

When aortic valve replacement is performed in a patient with a small anulus, significant obstruction of the left ventricular outflow tract may remain. Most prostheses are obstructive in the smaller sizes, and enlargement of the aortic anulus may be required to allow placement of a larger valve. To evaluate the hemodynamic performance of two commonly used tissue prostheses, the Ionescu-Shiley pericardial and Carpentier-Edwards porcine valves, 22 patients with either the 19 or 21 mm size were electively studied at rest and after exercise at a mean of 15 months after operation. The resting mean transvalvular gradient for 19 mm Ionescu-Shiley pericardial valves (n = 7), 10.6 +/- 9.2 mm Hg, was significantly lower than that for 19 mm Carpentier-Edwards valves (n = 3), 33.3 +/- 2.1 mm Hg, p less than 0.01. Following exercise, the mean gradient for 19 mm Ionescu-Shiley pericardial valves rose only to 13.8 +/- 8.5 mm Hg. No exercise data were available for the 19 mm Carpentier-Edwards valve. Among patients with 21 mm Ionescu-Shiley pericardial valves (n = 7), the mean transvalvular gradient at rest was 5.6 +/- 9.5 mm Hg, not significantly different from that of patients with 21 mm Carpentier-Edwards valves (n = 5), 9.8 +/- 18.3 mm Hg. After exercise, the gradients rose to 16.0 +/- 10.0 mm Hg and 25.5 +/- 23.8 mm Hg for the Ionescu-Shiley pericardial and Carpentier-Edwards valves, respectively (no statistical significance). Cardiac index was not different between groups. Gradients were not significantly higher in patients with body surface areas greater than 1.5 m2. It is concluded that the 19 and 21 mm Ionescu-Shiley pericardial valves possess excellent hemodynamics, even after exercise. This valve appears hemodynamically superior to the Carpentier-Edwards valve, particularly in the 19 mm size. Procedures to enlarge the aortic anulus are usually unnecessary when small Ionescu-Shiley pericardial valves are used, even in patients who have large body surface areas.     

The Ionescu-Shiley valve: a solution for the small aortic root

Valve replacement in patients with a small aortic anulus can cause difficult technical problems or leave the patient with a significant residual transvalvular gradient. Between August, 1977, and June, 1983, 35 patients with a small aortic root (21 mm or less) underwent aortic valve replacement with Ionescu-Shiley pericardial xenograft valves. They ranged in age from 29 to 76 years (mean 52.8 years) and in weight from 64 to 91 kg (mean 76.3 +/- 3.6 kg). Preoperatively, 26 patients were in New York Heart Association Functional Class III-IV. The valve sizes used were 17 mm in three cases, 19 mm in 16 cases, and 21 mm in 16 cases. There were four hospital deaths (11.4%) resulting from sepsis or low cardiac output. There were no late deaths. Cumulative duration of follow-up was 819.4 patient-months. Twenty-four (78%) of the 31 surviving patients are asymptomatic. Up to the time of review, there have been no episodes of thromboembolism, infective endocarditis, perivalvular leak, valve thrombosis, or primary tissue valve failure. Fifteen patients were hemodynamically evaluated 2 to 47 months (mean 14.3 months) after operation. The average resting transvalvular gradients for 19 and 21 mm valves were 15.1 and 10.8 mm Hg, respectively. Our experience suggests that the Ionescu-Shiley pericardial xenograft valve is a valid alternative in the surgical treatment of patients with a small aortic root.     

Porcine versus pericardial bioprostheses: a comparison of late results in 1,593 patients

From 1976 to 1988, 1,593 patients underwent valve replacement with a porcine (878 patients) or a pericardial bioprosthesis (715 patients). There were 701 aortic, 678 mitral, and 214 multiple-valve replacements. Follow-up was obtained for 1,559 patients (98%). Early mortality was 9% (79 patients) in the porcine valve group and 5% (37 patients) among patients with a pericardial valve (p less than 0.01). Late survival after replacement with porcine valves was 80% +/- 1% and 62% +/- 3% at 5 and 10 years, respectively. With pericardial valves, 5-year survival was 79% +/- 2%. Among valve-related complications, rates of freedom from thromboembolism, endocarditis, and hemorrhage after 6 years were similar for both valve groups. Freedom from reoperation at 6 years was also similar after aortic (96% versus 91%) or multiple-valve replacement (95% versus 88%). However, for mitral valve replacement, freedom from reoperation was significantly better with porcine valves than with pericardial valves at 6 years (92% versus 68%; p less than 0.001). This difference was mainly due to the Ionescu-Shiley valve, which accounted for 83% of primary tissue failures among pericardial bioprostheses implanted in the mitral position (10/12 patients). After 6 years, freedom from primary tissue failure of mitral valves was 92% +/- 2% with porcine and 70% +/- 11% with pericardial bioprostheses (p less than 0.0001). The degree of clinical improvement among survivors was similar with both valve types. Thus, in the aortic position, pericardial valves compare with porcine valves up to 6 years, whereas in the mitral position, the durability of the former is significantly less, mainly because of the suboptimal performance of the Ionescu-Shiley pericardial bioprosthesis.     

Clinical and hemodynamic results of cardiac valve replacement with the Monostrut Bj?rk-Shiley prosthesis

Between May 1983 and April 1986, 318 patients underwent cardiac valve replacement with the Monostrut Bj?rk-Shiley prosthesis. There were 136 aortic valve replacements, 128 mitral valve replacements, and 54 multiple replacements. A total of 373 valves were implanted. Associated procedures were done in 79 (25%) of the patients. Hospital (30-day) mortality rate was 5.6% (18 patients): 2.9% (n = 4) after aortic, 7.8% (n = 10) after mitrals and 7.4% (n = 4) after multiple valve replacement. Follow-up was obtained in all 300 operative survivors, for a total of 500 patient-years (mean 18 months). Actuarial survival rate, excluding operative deaths, at 4 years was 94.7% +/- 1.5% (mean +/- standard error of the mean). There were 16 thromboembolic episodes (3.2/100 patient-years). Freedom from all valve-related complications was 87% +/- 2.4% at 3 1/2 years. Neither valve thrombosis nor structural failure has been observed. Eighty percent of the patients are in New York Heart Association functional class I. Forty-two patients (26 with aortic and 16 with mitral valve replacement) underwent cardiac catheterization a mean of 6 1/2 months after the operation. In the aortic position, peak gradients were an average of 6.9 +/- 1.2 mm Hg. Mean systolic gradients were 12.4 +/- 6.3 mm Hg and did not increase with exercise. In the mitral position, end-diastolic gradients were an average of 2.1 +/- 2 mm Hg and mean gradients, 5.9 +/- 2 mm Hg. Discharge coefficient (estimated orifice area/geometric area) was 0.63 +/- 0.2 for the aortic and 0.53 +/- 0.2 for the mitral prostheses. Disc opening was maximal in most patients. These results indicate that the Monostrut prosthesis has a low rate of thromboembolic events, no structural failures or thrombotic obstructions and excellent hemodynamic performance, especially in the small aortic sizes (discharge coefficient for 19 and 21 mm valves, 0.77).     

Clinical and hemodynamic evaluation of the 19-mm Carpentier-Edwards supraannular aortic valve.

The clinical and hemodynamic performance of the 19-mm Carpentier-Edwards supraannular aortic valve is largely unknown compared with that of the larger valves. Over 4 years we implanted the 19-mm Carpentier-Edwards supraannular aortic valve into 21 patients (20 female) with a mean age of 75 +/- 1.2 years (range, 59 to 86 years) and a mean body surface area of 1.6 +/- 0.03 m2 (range, 1.3 to 1.7 m2). There were four deaths, one operative and three late noncardiac deaths. Follow-up of the 17 survivors for a mean of 20 +/- 3.1 months (range, 2 to 42 months) demonstrated symptomatic improvement in all 17 (all are now in New York Heart Association functional class I or II). There were no valve-related complications and no patient required long-term anticoagulation. Doppler echocardiographic studies were used to assess the in vivo hemodynamic profile of the valve. Mean postoperative aortic valve gradient was 34.1 +/- 2.7 mm Hg (range, 19 to 52 mm Hg). Functional valve orifice area was 1.1 +/- 0.09 cm2 (range, 0.6 to 1.8 cm2). Mean cardiac output was 3.92 +/- 0.17 L/min (range, 3.2 to 5.1 L/min) with a mean cardiac index of 2.5 +/- 0.11 L.min-1 x m-2 (range, 2.1 to 3.2 L.min-1 x m-2). In conclusion, we have demonstrated that aortic valve replacement with the 19-mm Carpentier-Edwards supraannular aortic valve has a low operative mortality and offers major clinical benefits despite moderate transprosthetic gradients. This approach provides an alternative management strategy in elderly patients who would otherwise require low-profile mechanical valves or aortic root enlargement.     

Left ventricular outflow tract obstruction with mitral valve replacement in small ventricular cavities

The inference that mitral valve replacement (MVR) may produce left ventricular outflow tract (LVOT) obstruction has been made, but no comparative hemodynamic studies with various types of prostheses have been done. The purpose of the present study was to compare the gradients created across the LVOT with MVR in young sheep with small left ventricular cavities. Mitral valve replacement was accomplished using cardiopulmonary bypass and hypothermic cardioplegic arrest. Five animals were used for each of the following valves studied: 25-mm Ionescu-Shiley bovine pericardial valve, 25-mm Hancock porcine aortic valve, 2M-6120 28-mm Starr-Edwards ball-valve prosthesis, 25-mm Bj?rk-Shiley 60-degree flat tilting-disc prosthesis, and 25-mm St. Jude Medical hemidisc valve. Gradients across the LVOT were measured after MVR and then during infusion of isoproterenol hydrochloride (0.05 micrograms/kg/min). Following MVR, only the Starr-Edwards valve produced an LVOT gradient (32 +/- 23 mm Hg). Substantial gradients after MVR were seen, however, with isoproterenol administration with the Ionescu-Shiley (47 +/- 4 mm Hg), Hancock (13 +/- 8 mm Hg), and Starr-Edwards (65 +/- 30 mm Hg) valves but not with the low-profile valves (Bj?rk-Shiley and St. Jude Medical). The results of the present study demonstrate that MVR can produce LVOT obstruction. The greatest degree of obstruction was with the high-profile mechanical and bioprosthetic valves.     

Use of stentless xenografts in the aortic position: determinants of early and late outcome

BACKGROUND: Whether to perform a stentless aortic valve replacement (AVR) is not well established. Our aim was to determine the outcome after AVR with stentless xenograft valves. METHODS: Between 1996 and 2001, a total of 404 patients (mean age 70.4 years) underwent a stentless AVR by one surgeon in our unit. Concomitant procedures were performed in 132 patients (33%). Twenty patients (6.4%) had undergone previous AVR. Eleven types of stentless xenograft valves were implanted: Medtronic Freestyle in 221 patients (55%), Shelhigh in 55 (14%), Shelhigh composite conduit in 33 (8%), Sorin in 26 (6%), Cryolife O'Brien in 25 (6%), Aortech-Elan in 17 (4%), Edwards Prima in 14 (4%), Toronto SPV in 7 (2%), and other valves in 6 (1%). A subcoronary implantation technique was used in 302 cases (76%), complete root replacement in 62 (15%), and a modified Bentall-De Bono procedure in 33 (8%). Mean follow-up was 19.4 months (range, 1.2 to 60.6 months). RESULTS: Overall hospital mortality was 4.2%. This was 2.4% for isolated AVR, 3.6% for AVR and coronary artery bypass grafting, 5.5% for replacement of two or more valves, and 12% for the modified Bentall procedure. On multiple logistic regression redo cardiac operation (p = 0.0006), cardiogenic shock (p = 0.001), left ventricular ejection fraction less than 0.30 (p = 0.01), modified Bentall procedure (p = 0.03), and endocarditis (p = 0.04) were predictors of in-hospital death. Five-year freedom from thromboembolism, hemorrhage, prosthetic endocarditis, structural valve deterioration, and reoperation was 97%, 99%, 99%, 98%, and 96%, respectively. Kaplan-Meier survival at 5 years was 88%. On Cox regression, cardiogenic shock (p = 0.001) and older age (p = 0.03) were adverse predictors of survival. At echocardiographic examination within 6 months from the operation, mean aortic valve gradients were 15 +/- 6 mm Hg, 12.8 +/- 3 mm Hg, 10.8 +/- 4 mm Hg, 9.3 +/- 3 mm Hg, 9.1 +/- 4 mm Hg, and 8.2 +/- 3 mm Hg for valve sizes of 19, 21, 23, 25, 27, and 29 mm, respectively. CONCLUSIONS: The availability of several stentless valve designs facilitates the surgical treatment of diverse aortic valve or root diseases with encouraging early and mid-term results. Patients requiring concomitant procedures may also benefit from the excellent hemodynamic characteristics of a stentless valve. We consider stentless AVR the treatment of choice for patients older than 60 years and those having small aortic roots.     

Five-year experience with the Ionescu-Shiley bovine pericardial valve in the aortic position

Between February, 1977, and April, 1982, 168 patients underwent aortic valve replacement (AVR) with an Ionescu-Shiley bovine pericardial valve. Concomitant procedures were performed in 71 patients. There were 12 hospital deaths (7.1%). Among patients having AVR only, there were 5 deaths (5.2%). Assessment included valve durability, incidence of thromboembolism, clinical improvement, and patient survival. There was 100% follow-up. Actuarial freedom from intrinsic valve failure at 5 years was 96.3 +/- 3.6%. Intrinsic valve failure occurred only once, 0.3 episodes per 100 patient-years. Four patients had thromboembolic complications. As for clinical status, 99.3% of surviving patients are in New York Heart Association Functional Class I or II, including 79 patients with valve sizes 17, 19, or 21 mm (56%). Among 13 late deaths, 9 were related to the cardiovascular system. Overall patient survival is 84.9 +/- 4.7%. Among the 92 patients with isolated AVR, 87.8 +/- 5.9% are alive at the 5-year follow-up. If the incidence of valve failure is not altered in years to come, the durability of the Ionescu-Shiley bovine pericardial valve will surpass that of previous bioprostheses.     

Functional hemodynamic assessment of the 21-mm and 23-mm CarboMedics Top Hat aortic prosthetic valve

Between 1993 and 1996 the CarboMedics Top Hat supraannular aortic valve was implanted in 41 patients at the Wessex Cardiothoracic Centre (age, 39 to 74 years; mean, 61.3+/-8.9 years). Comparisons of annular dimensions made at surgery indicate that conventional annular valve replacement would have required at least a size smaller valve. This was particularly marked when a prosthetic mitral valve was in place. Operative mortality was 2.4%. There were also three late deaths. Echocardiography before and after symptom-limited treadmill testing has been performed in 21 patients. The mean time to follow-up was 16.1 months. The Doppler-derived indices of forward flow pre- and postexercise were expressed as mean+/-standard deviation. For 23-mm valves the values were: peak valve gradient 21.43+/-7.46 mm Hg and 35.86+/-14.4 mm Hg, aortic valve area 1.13+/-0.39 cm2 and 1.24+/-0.54 cm2. For 21-mm valves the values were: peak valve gradient 24.84+/-8.2 mm Hg and 31.29+/-5.84 mm Hg, aortic valve area 1.08+/-0.44 cm2 and 0.95 +/-0.2 cm2. The Top Hat valve has a good hemodynamic profile at rest and during exercise. Surgical considerations make it particularly useful in patients with a small aortic annulus and in patients undergoing combined aortic and mitral valve replacement.     

Ionescu-Shiley pericardial xenografts: follow-up of up to 6 years

The results of valve replacement with the Ionescu-Shiley pericardial xenograft compare favorably with results obtained with other bioprostheses. From March, 1977, to July, 1983, 497 Ionescu-Shiley pericardial valves were implanted in 463 patients at the University of Ottawa Heart Institute. There were 292 patients who had aortic valve replacement (AVR), 140 with mitral valve replacement (MVR), 28 with double valve replacement, and 3 with triple valve replacement. The survivors were followed regularly. Actuarial analysis of late results indicates an expected survival of 71% at 6 years for patients who underwent AVR and 72% at 3 years for patients who had MVR. The only valve-related deaths were due to endocarditis, which occurred at a rate of 3.9% per patient-year for aortic valves and 0.6% per patient-year for mitral valves. Despite a low usage of formal anticoagulation, embolic complications occurred at a rate of 1.4% per patient-year for aortic valves and 4.0% per patient-year for mitral valves. Five valves were removed for intrinsic failure after 36 to 72 months of follow-up. New York Heart Association Functional Class improved an average of 1.28 classes per patient.     

Valve-sparing aortic root replacement in bicuspid aortic valves: a reasonable option?

OBJECTIVES: Aortic dilatation occurs in many patients with bicuspid aortic valves. We have added root replacement using the remodeling technique originally designed for tricuspid aortic valves to bicuspid aortic valve repair for treatment of the dilated root. We compared the results of remodeling in bicuspid aortic valves with those in tricuspid aortic valves. METHODS: From October 1995 through January 2004, 60 patients underwent root remodeling for bicuspid aortic valves (group A), and 130 patients underwent root remodeling for tricuspid aortic valves (group B). Correction of cusp prolapse was more often performed in group A (group A, 50/60; group B, 47/130; P < .0001). Transthoracic echocardiography was performed at 1 week, 6 and 12 months, and every year thereafter. Cumulative follow-up was 527 patient-years (mean, 2.9 +/- 2 years). RESULTS: No patient died in group A. Hospital mortality in group B was 5% (5/100; 95% confidence interval,1.6%-11.3%) after elective operations and 10% (3/30; 95% confidence interval, 2.1%-26.5%) after emergency operations. Mean systolic gradients were identical at 1 year (group A, 4.8 +/- 2.1 mm Hg; group B, 4.0 +/- 2 mm Hg) and 5 years (group A, 4.5 +/- 2.3 mm Hg; group B, 3.9 +/- 2.2 mm Hg). Freedom from aortic regurgitation of grade 2 or higher at 5 years was 96% in group A and 83% in group B ( P = .07), and freedom from reoperation at 5 years was 98% in group A and 98% in group B ( P = .73). CONCLUSIONS: Valve-sparing aortic replacement with root remodeling can be applied to aortic dilatation and a regurgitant bicuspid aortic valve. Hemodynamic function and valve stability of a repaired bicuspid aortic valve are comparable with those seen in cases of tricuspid anatomy.     

A five-year appraisal and hemodynamic evaluation of the Bj?rk-Shiley Monostrut valve

Two hundred forty-four Bj?rk-Shiley Monostrut valves were implanted in 225 consecutive patients from October 1983 to December 1988. Aortic valve replacement was performed in 90 patients, mitral valve replacement in 118, and double valve replacement in 16 patients. One patient had tricuspid valve replacement. There were 100 female patients and 125 male patients with a mean age of 54 years (range 2 to 71 years). Present data were completely available for all patients. The cumulative follow-up was 541 patient-years with a mean of 2 years, 5 months. The closing date for follow-up was July 1989, and the closing interval was 2 months. The early mortality rate was 3.1%, and the late mortality rate, 3.1%. The 5-year survival rate was 88% +/- 2.0%: 87% +/- 3.0% for aortic valve replacement, 91% +/- 3.3% for mitral valve replacement, and 75% +/- 9.6% for double valve replacement. The actuarial rates of freedom from thromboembolism at 5 years were 93% +/- 3.2% for aortic, 96% +/- 1.4% for mitral, and 94% +/- 6.1% for double valve replacement. There were no instances of structural valve deterioration. Actuarial rate of freedom from valve-related morbidity and mortality was 86% +/- 2.0% at 5 years: 86% +/- 9.5% for aortic, 87% +/- 3.3% for mitral, and 75% +/- 7.3% for double valve replacement. Effective valve areas (average) of 12 mitral and 12 aortic valve prostheses were calculated at rest and during bicycle exercise: 2.4 cm2 at rest and 2.8 cm2 during exercise in 27 mm aortic valves, 2.4 cm2 at rest and 3.0 cm2 during exercise in 25 mm aortic valves, 2.0 cm2 at rest and 2.4 cm2 during exercise in 27 mm mitral valves, and 2.6 cm2 at rest and 2.5 cm2 during exercise in 29 mm mitral valve. On the basis of our follow-up period of 5 years, we have judged the Bj?rk-Shiley Monostrut valve reliable, with a low incidence of valve-related morbidity and with acceptably satisfactory hemodynamic characteristics at rest and during exercise.     

Cardiac valve replacement in the elderly]

From January 1980 through December 1990, seventy one consecutive patients over 60 years of age (mean age 64 +/- 4 years) and 231 patients younger than 60 years underwent cardiac valve replacement procedures. In the elderly group, aortic valve replacement was performed in nineteen patients, mitral valve replacement in thirty-three patients both aortic and mitral valve replacement in sixteen patients, and both mitral and tricuspid valve replacement in three patients. Aortocoronary bypass was performed in four and tricuspid annuloplasty in 19 patients simultaneously. Two patients were operated on emergency. As for preoperative status, 63 patients (88.7%) were in New York Heart Association (NYHA) Functional Class III or IV. Mechanical valves were implanted in all aortic position and 16 mitral position. Bioprosthetic valves were placed in 34 mitral position and 3 tricuspid position. Mean follow-up period was 42 +/- 33 months. The early mortality rate was 11% (8 patients) and the actuarial survival rate was 88 +/- 5% at five years and 74 +/- 10% at ten years. Postoperative functional improvement was excellent in 85.7% of the survivors. In the younger age group, 77.9% belonged to NYHA class III or IV preoperatively. The early mortality was 3.0% (7 patients) and the actuarial survival rate was 95 +/- 2% at five years and 86 +/- 2% at ten years. And postoperatively 91.3% were in NYHA class I or II. In conclusion, cardiac valve replacement in the elderly can be performed with an acceptable mortality and excellent functional improvement.     

Long-term clinical results with the Ionescu-Shiley pericardial xenograft

From 1977 to 1987, 829 Ionescu-Shiley pericardial valves (Shiley, Inc., Irvine, Calif.) were implanted in 766 patients at the University of Ottawa Heart Institute. There were 476 patients who had aortic valve replacement, 234 who had mitral valve replacement, and 44 who had double valve replacement. The standard-profile design was used in 508 patients and the low-profile design in 321 patients. Follow-up was obtained for 97% of patients, with calculation of event-free probabilities. At 10 years the overall probability of freedom from structural failure was 48% +/- 7% after aortic valve replacement, 44% +/- 15% after mitral valve replacement, and 79% +/- 11% after double valve replacement. Although at 5 years the probability of failure was statistically lower with the low-profile design, this favorability was lost by 6 years. Freedom from structural failure was only 47% +/- 7% for the standard-profile valve at 10 years. Thus the probability of freedom from reoperation was only 46% +/- 7% after aortic valve replacement, 39% +/- 6% after mitral valve replacement, and 65% +/- 20% after double valve replacement at 10 years. Thromboembolism occurred in 69 patients, for a predicted freedom from this complication at 10 years of 79% +/- 3% after aortic, 73% +/- 7% after mitral, and 96% +/- 4% after double valve replacement. There were 31 cases of endocarditis. The 10-year predicted freedom from endocarditis, therefore, was 86% +/- 3% after aortic, 98% +/- 1% after mitral, and 97% +/- 1% after double valve replacement. A total of 221 operative and late deaths were recorded in this series. Prosthetic valve failure accounted for 27% of late deaths. The 10-year survival rates were estimated to be 56% +/- 5% (aortic valve replacement), 54% +/- 6% (mitral valve replacement), and 51% +/- 8% (double valve replacement). We concluded that the Ionescu-Shiley pericardial xenograft provides less than optimal clinical performance and its use has been discontinued.     

Late results after Starr-Edwards valve replacement in children

Selection of types of prosthetic heart valves for children remains controversial. The case histories of 50 children surviving valve replacement with Starr-Edwards prostheses between 1963 and 1978 were reviewed to evaluate the long-term performance of mechanical valves. The 31 boys and 19 girls ranged from 6 months to 18 years in age (mean 10.4 years); 19 patients had had aortic valve replacement, 24 patients had had mitral valve replacement, and one patient had had both. Among the six patients who had had tricuspid valve replacement, four had corrected transposition, so that the tricuspid valve was the systemic atrioventricular valve. Mean (+/- standard deviation) follow-up interval was 7.9 +/- 4.9 years (maximum 17 years). For all patients, the 5 year survival rate was 86% +/- 6%. At 10 years postoperatively, the survival rate (+/- standard error) was 90% +/- 7% after aortic valve replacement and 76% +/- 8% after systemic atrioventricular valve replacement. At follow-up, 39 patients were alive, and 38 were in New York Heart Association Class I or II. Of the 11 deaths, four were valve-related. Seven patients had major (requiring hospitalization) thromboembolic events, and five patients had minor transient neurological symptoms suggesting thromboembolism; 50% of these patients were not taking warfarin (Coumadin) at the time of the thromboembolic event. The incidence of late (greater than 30 days) thromboembolism was 5.3 per 100 patient-years after aortic and 2.0 per 100 patient-years after systemic atrioventricular valve replacement. At 10 years postoperatively, 66% +/- 15% of patients who had had aortic valve replacement and 91% +/- 6% of those who had had systemic atrioventricular valve replacement were free of thromboembolism. The excellent long-term survival, absence of mechanical failure, and relatively low rate of thromboembolism with this prosthesis contrast with our experience with biological valves, in which 41% of children required reoperation in 5 years. Currently, mechanical valves, such as the Starr-Edwards prostheses, are our preferred valves for pediatric patients.     

The Monostrut Bj?rk-Shiley valve. Seven years' experience.

The results of cardiac valve replacement with the Monostrut Bj?rk-Shiley prosthesis (Shiley, Inc., Irvine, Calif.) during a 7-year period are presented. A total of 984 valves were implanted in 820 patients from May 1983 to April 1990. Aortic valve replacement was performed in 378 patients, mitral replacement in 294, and multiple replacement in 148. In addition, 180 patients (22%) underwent associated procedures. Mean age was 52.6 +/- 11 years. Operative (30 days) mortality was 5.9% (49 patients): 3.9% (15 patients) for aortic, 7.8% (23 patients) for mitral, and 7.4% (11 patients) for multiple valve replacement. All patients were given long-term anticoagulation therapy. Follow-up was 99% complete (eight patients were lost to follow-up), with a closing interval of 3 months, and totaled 2422 patient-years. Valve-related complications, expressed as percentage event-free (+/- standard error) at seven years were as follows: structural deterioration, 100%; nonstructural dysfunction, 98.3% +/- 0.6%; thromboembolism, 90.2% +/- 1.7%; anticoagulant-related hemorrhage, 88.7% +/- 2.8%; and prosthetic valve endocarditis, 98.1% +/- 0.8%. There were no cases of valve thrombosis. Actuarial survival (free from operative, valve-related, and sudden death) was 88.4% +/- 1.2% at 7 years. Freedom from reoperation was 96.8% +/- 0.1%. Probability of being free from all valve-related morbidity and mortality was 70% +/- 3%, and 708 (93%) of the survivors were in New York Heart Association class I or II. Serial Doppler echocardiograms were done prospectively in 243 patients (with 154 aortic and 120 mitral prostheses), both postoperatively and at regular intervals up to 3 years. Mean prosthetic gradients ranged from an average of 20.9 to 7 mm Hg in the aortic prostheses (21 to 29 mm) and from 6.1 to 4.8 mm Hg in the mitral prostheses (25 to 31 mm). The gradients in each patient did not change significantly during the follow-up period. Our 7 year's experience with the Monostrut valve shows a low rate of valve-related complications, a durable design, and good hemodynamic and functional results.     

Valve replacement in the right side of the heart in children: long-term follow-up

Twenty-five patients (16 male, 9 female) underwent right-sided valve replacement (10 pulmonary valve replacement, 14 tricuspid valve replacement, 3 tricuspid plus pulmonary valve replacement, and 2 replacements of a single atrioventricular valve) at the University of Nebraska Medical Center from June 1977 to December 1986. Twenty-one patients (84%) are long-term survivors with 2,035 months follow-up (range, 41 to 143 months; mean, 96.9 months). Twenty-three Carpentier-Edwards bioprosthetic valves, one Ionescu-Shiley bioprosthetic valve, and nine St. Jude Medical valves were inserted. Follow-up of 17 patients with a Carpentier-Edwards valve ranged from 5 years 9 months to 11 years 9 months (mean, 8 years 11 months). To date there has been one reoperation after 3 years 4 months in this group. One patient who received an Ionescu-Shiley bioprosthesis required re-replacement at 20 months after operation. Three of 4 patients who received St. Jude mechanical valves and are long-term survivors have required replacement after 36 to 56 months. We conclude that the Carpentier-Edwards bioprosthetic valve is a viable option in the right side of the heart in the young age group when annular size is adequate to accommodate an appropriate bioprosthesis.     

Valve replacement in narrow aortic roots: serial hemodynamics and long-term clinical outcome

No long-term data are available that correlate clinical outcome with serial hemodynamic studies for small-diameter (17-mm or 19-mm) aortic prostheses implanted without enlargement of the annulus. After insertion of these valves without annuloplasty, 52 patients underwent resting catheterization and were followed up at the Surgery Clinic of the National Heart, Lung, and Blood Institute for 295 patient-years (mean, 5.7 years per patient). At similar flow rates, peak systolic gradients across 17-mm Bj?rk-Shiley aortic prostheses (N = 6) tended to exceed those of the 19-mm Bj?rk-Shiley model (N = 38); these gradients averaged 30 +/- 6 mm Hg (mean +/- standard error of the mean) and 20 +/- 2 mm Hg, respectively (p = .053). Those patients with 19-mm Hancock (N = 4) and St. Jude Medical valves (N = 4) were studied, and the lowest prosthetic gradients were found with the St. Jude Medical prosthesis (mean, 3 +/- 2 mm Hg). Aortic gradient was independent of flow for 17-mm but not for 19-mm Bj?rk-Shiley valves. There was no difference in calculated effective orifice area with respect to valve size. Effective orifice area and prosthetic gradients were stable during intervals of 2 to 12 years in 10 patients who underwent additional catheterizations. No association was found between prosthetic gradients, flows, or calculated orifice areas and early or late functional class. Actuarial survival was 86 +/- 5% at 5 years, 83 +/- 5% at 8 years, 71 +/- 9% at 10 years, and 60 +/- 12% at 12 years of complete follow-up. It is concluded that small aortic prostheses provide acceptable palliation for long periods and that resting hemodynamic studies have a limited predictive value for long-term prognosis.     

Long-term results of valve replacement in the right side of the heart in congenital heart disease--comparative study of bioprosthetic valve and mechanical valve

Valve replacements in the right side of the heart (TVR and PVR) were done on 16 patients with congenital heart disease, mainly tetralogy of Fallot and Ebstein anomaly. Including reoperations, 19 operations were performed on them and 20 artificial valves were inserted. Ten mechanical valves (7 St. Jude Medical valves, 3 Starr-Edwards valves) and 10 bioprosthetic valves (7 Carpentier-Edwards valves, 3 Ionescu-Shiley valves) were used. Age at valve replacement ranged from 9 to 52 years (mean 23.0 years), and the follow-up period was 1.28-19.8 years (mean 5.7 years). Including 2 sudden deaths, late death occurred in 4 patients, on all of whom mechanical valve replacements were done at the primary operation. Five-year survival rate of all patients was 76.4 +/- 12.1%, and 10-year survival rate was 63.6 +/- 15.4%. All the patients who received bioprosthesis at the primary operation survived at the time of this follow-up study. On the contrary, long-term results of mechanical valve was unsatisfactory with the 5-year survival of 62.5 +/- 17.1%. In spite of anti-coagulation therapy with warfarin, three patients with mechanical valve complicated thrombotic valves, which necessitated re-operations. Calcified bioprosthetic valve occurred in one patient with I-S valve 8.5 years after the implantation. Five-year complication-free rate was 87.5 +/- 11.7% for bioprosthesis, whereas it was 50.0 +/- 15.8% for mechanical valve (p less than 0.056). It is concluded that the bioprosthesis is the first choice for the valve replacement in the right side of the heart in congenital heart disease.     

Left ventricular outflow tract obstruction following mitral valve replacement: effect of strut height and orientation

The influence of strut position and strut height of Ionescu-Shiley bovine pericardial valves on the degree of left ventricular outflow tract (LVOT) obstruction was studied following mitral valve replacement (MVR) in hypertrophied left ventricles. Left ventricular hypertrophy was created in 6 lambs by constrictive banding of the descending thoracic aorta at 2 weeks of age. MVR was accomplished seven months later utilizing cardiopulmonary bypass and hypothermic cardioplegic arrest. Each animal underwent three consecutive valve replacements with 25-mm bovine pericardial valves randomly inserted in each of the following manners: (1) standard-profile valve with orientation of the struts out of the LVOT; (2) standard-profile valve with a strut oriented into the LVOT; and (3) low-strut profile investigational valve with a strut oriented into the LVOT. Gradients across the LVOT were measured after MVR and then following administration of isoproterenol hydrochloride (0.05 micrograms per kilogram of body weight per minute). No gradient was created with the struts oriented out of the LVOT with or without isoproterenol administration. When a strut was oriented into the LVOT without isoproterenol, the gradients were comparable with the standard- and low-profile valves (7 +/- 2 mm Hg versus 6 +/- 4 mm Hg, respectively). With isoproterenol, however, a significant difference in gradients between the standard- and low-profile valves (65 +/- 20 mm Hg versus 22 +/- 14 mm Hg, respectively) was observed when a strut was oriented into the LVOT. The results show that LVOT obstruction following MVR was related to the orientation of the strut of the bioprosthetic valve, and this obstruction was diminished with a decreased strut height of the Ionescu-Shiley prosthesis.