Long-term echocardiographic Doppler monitoring of Hancock bioprostheses in the mitral valve position.

Echocardiographic and Doppler studies were performed in 134 patients with a Hancock bioprosthesis in the mitral valve position during a follow-up period of 1 to 216 months. Among the xenografts, 57% were clinically normal and 43% had severe dysfunction. Among the normal bioprostheses, 35% had echocardiographically thickened mitral cusps (> or = 3 mm) with normal hemodynamic function; by setting the lower 95% confidence limit of valve area at 1.7 cm2 these patients had a significantly (p < 0.01) smaller valve area than that of normal control subjects. Evaluation of all thickened normal mitral valves showed the highest incidence of thickening at 9 years after implantation. Valve replacement surgery was subsequently performed in 33 patients with dysfunctioning bioprosthetic and echocardiographic diagnosis was confirmed in 91% of explanted valves (bioprosthetic stenosis 21%, incompetence 46%, and combined stenosis and regurgitation 33%). In 2 valves that were found to be stenotic on echocardiographic examination, a calcium-related commissural tear was also observed at reoperation, and in another, a paravalvular leak was found. Dystrophic calcification, isolated (64%) or occasionally associated with fibrous tissue overgrowth (21%), was the main cause of failure. Pannus was present in prostheses with longer satisfactory function (168 +/- 31 vs 124 +/- 21 months; p < 0.001). Long-term performance was evaluated by the Kaplan-Meier method for up to 18 years of follow-up. Freedom from structural valvular disfunction after mitral replacement was 89% at 6 years, 77% at 8 years, 56% at 10 years, 31% at 12 years, 16% at 15 years, and 15% at 18 years.     

Long-term (8 years) follow-up study of 204 bioprostheses

From june 1974 to december 1975, 204 Hancock prosthetic valves were engrafted. The in-hospital mortality was 8.7%. The eight year survival rate was 78.9%. Of the 171 patients who had surgery, 121 reverted to functional class I, 123 had a mild or absent cardiomegaly. After 8 years of follow up 92% of the cases had not thromboembolic episodes. Ninety five percent of the patients with mitral valve replacement and 95% with aortic valve replacement were free of bacterial endocarditis. During the follow-up period; there were 49 valvular malfunctions, 16 of them mild that required no treatment. In 32 cases the alteration was severe and required surgical intervention. Thirty six prosthetic valves had to be removed; 22 of them had degenerative changes, 10 had bacterial endocarditis and in 4 the suture line broke down. After 8 years 77% of the valves were functioning well. The in-hospital mortality after the second valve replacement was 9.4%.     

Long-term outcome of bioprostheses

The major advantage of cardiac bioprostheses, apart from the good haemodynamic performance of recent models, is that they are not thrombogenic, so that the patient does not have to follow a life-long anticoagulant treatment. However, their major disadvantage, in comparison with the mechanical prostheses, is that they deteriorate over time. This study defines the durability of bioprostheses over the first seven years and beyond seven years. During the first seven years, if we compare the risk of thromboembolic and haemorrhagic complications of anticoagulant treatment to the risks of tissue deterioration, there is a clear advantage in favour of the bioprostheses. However, this is only true in adults, as in patients under the age of 20, the bioprostheses deteriorate much more rapidly. Few statistics are available concerning the followup of bioprostheses beyond seven years. However, on the basis of these statistics, absence of deterioration was observed in 75% of cases at 9 years and in 65% of cases at 10 years. These figures demonstrate that the great majority, if not all, cases of bioprostheses implanted at the present time will not need to be changed before 8 to 15 years. These results justify the research currently underway in various centres to determine the cause of these deteriorations and to try to prevent them.     

Reoperation on valve bioprostheses. Apropos of 64 cases

Sixty-four patients with one or more bioprostheses were reoperated between 1970 and 1982. Reoperation was performed for degenerative lesions in cases (48%), for aseptic periprosthetic leaks in 18 cases (28%), for infectious lesions in 13 cases (21%) and for thrombosis in 2 cases (3%). Degenerative and infectious lesions were commoner in aortic bioprostheses whilst periprosthetic leaks were commoner in mitral bioprostheses. The average interval between operations was 38 months. This was shorter in patients reoperated for mechanical problems (6 months) than those with infections (28 months) or degenerative (5 years) complications. At reoperation 14 prostheses were reinserted and 50 were replaced. The global hospital mortality was 21% (14 deaths). The mortality was related to the surgical indication: mechanical lesions (11%), degenerative lesions (16%), infectious endocarditis (38%), thrombosis (100%). The mortality rate also varied with time (36% during the period 1970-1978 and 18% during the period 1979-1982). This improvement was related to two factors: the use of cardioplegic solutions for myocardial protection and earlier recognition of surgical indications before the onset of irreversible haemodynamic complications. When choosing a valvular prosthesis, the mortality of reoperation for degenerative changes is the only disadvantage of the bioprosthesis which is silent, rarely complicated by thromboembolism and which does not require anticoagulant therapy for life. The mortality has decreased with time and will continue to fall if the indications for reoperation are based on stethacoustic, electrical, radiological and echocardiographic criteria of valvular dysfunction and not on the presence of overt cardiac failure as is still often the case.     

Diagnosis of dysfunctions of heart valve bioprostheses

Twenty-three cases of bioprosthetic dysfunction due to infectious endocarditis and primary tissue degeneration are reviewed. Twelve bioprostheses were studied morphologically. Follow-up of bioprosthesis-wearers for timely diagnosis of bioprosthetic dysfunction can be based on routine clinical investigation procedures. Echocardiographic detection of calcified vegetations on the cusps, as well as thrombosis, incompetence and marked stenosis of the bioprosthesis are indications for repeated surgery.     

Implications of prosthetic valve implantation: an 8-year follow-up of patients with porcine bioprostheses

Nurses in cardiovascular critical care settings routinely care for patients with implanted valvular prostheses. The presence of an artificial valve substitutes a new disease state for the preexisting valvular disease. Five hundred nine patients who underwent cardiac valve replacement with porcine bioprostheses and who were followed for a total of 1633 patient-years provide the data base for discussion of long-term survival, functional capacity, and morbidity associated with valvular prostheses. Seventy-two percent of patients survived 5 years after operation. New York Heart Association functional class was improved in 84%. Three major types of morbidity were documented: thromboembolism, endocarditis, and valve failure. Cardiovascular nurses should be familiar with the implications of valvular prostheses to provide appropriate patient education and to facilitate the prompt detection and treatment of valve-related complications.     

Structural changes in Hancock porcine xenograft cardiac valve bioprostheses.

Gross and histologic observations are described in 51 Hancock glutaraldehyde-preserved porcine heterograft bioprostheses from 41 patients: 33 valves from 25 patients had been in place for less than 2 months (early) and 18 valves from 17 patients were examined at later periods up to 75 months (late) after implantation. The major gross changes were cuspal thrombosis (5 bioprostheses) and cuspal degeneration (3 bioprostheses). Major histologic changes observed in 44 bioprostheses (26 early and 18 late) examined histologically were: (1) fibrin deposits on inflow and outflow surfaces of the cusps; (2) inflammatory cell infiltrates; (3) histiocyte deposition; (4) giant cell formation, and (5) focal disruption of the fibrocollagenous structure of the cusps. These observations indicate that porcine bioprostheses are not biologically inert in the human circulation. Valve failure, however, is rare at the implantation periods studied.     

Computer-assisted valve in valve in a deteriorated Mosaic valve using a library of bioprostheses

Valve-in-valve (ViV) procedures have emerged from an off-label procedure to a safe and efficient alternative to redo aortic valve replacement in the treatment of symptomatic structural valve deterioration (SVD). During ViV procedures, optimal placement of the transcatheter heart valve (THV) inside the degenerated bioprosthesis is of paramount importance regarding complications such as device embolization, coronary obstruction, periprosthetic regurgitation, residual gradients, and mitral valve injury, but also for the attainment of optimal hemodynamics. In the case of the Mosaic (Medtronic, Minneapolis, MN) valve, the limited radiopaque landmarks represent a challenge to a reproducible, optimal implantation. Such implantation may require multiple contrast injections and transesophageal echocardiogram (TEE) guidance. We herein describe a computer-assisted ViV procedure inside a deteriorated Mosaic valve, achieving reproducible optimal placement using a preacquired library of bioprostheses 3D models. Our approach suggests an evolving paradigm in ViV procedures, from safe and efficient toward optimal therapy for symptomatic SVD.     

Replacement of the mitral and aortic valves with bioprostheses. Long-term results

The purpose of the study was to analyze the medium-term results (late mortality, thromboembolism, valve failure) in patients who underwent bioprosthetic valve replacement at "A. De Gasperis" Cardiovascular Surgery Division. From October 1975 to December 1982, 195 patients were consecutively operated on and discharged (118 with mitral prosthesis, 54 with aortic prosthesis, 22 with mitral and aortic prosthesis, 1 with mitral and tricuspid prosthesis). We reviewed 115 (97.45%) of 118 patients with mitral prosthesis (mean follow-up 46.61 months) and 54 (100%) patients with aortic prosthesis (mean follow-up 38 months). Eleven late deaths (2.4%/pt-yr) and 13 thromboembolic events (2.8%/pt-yr) occurred in patients with mitral prosthesis, 6 late deaths (3.5%/pt-yr) and 5 thromboembolic events (2.9%/pt-yr) occurred in patients with aortic prosthesis. Actuarial survival curves and actuarial incidence of thromboembolic event-free patients at 5 years are, respectively, 91.2% and 87.3% in patients with mitral prosthesis, 82.8% and 86.3% in patients with aortic prosthesis. The risk factors for thromboembolism were analyzed. Reoperation was requested in 14 cases (10 mitral and 4 aortic prostheses) for prosthetic leak (6 patients) or valve failure (8 patients). In linearized terms, the rate of valve failure requiring reoperation is 1.3%/pt-yr for mitral prostheses and 1.1%/pt-yr for aortic prostheses. The medium-term results suggest that the bioprostheses are, at the present time, an effective choice to the mechanical prostheses, nevertheless they are not free from risks of thromboembolic complications.     

Hemodynamic evaluation of Ionescu-Shiley pericardial bioprostheses

36 patients with a total of 39 pericardial Ionescu-Shiley bioprostheses (20 aortic, 13 mitral and 3 double valve replacements) were studied. The population consisted if 12 women and 24 men with an average age of 33 +/- 11 years. The control was performed on average 7 +/- 4 months after surgery. At the time of investigation all patients were in functional classes I or II of the NYHA. The average cardio-thoracic ratio was 0.51 +/- 0.05. The catheter data showed a mean pulmonary capillary pressure of 10 +/- 2.7 mmHg, a mean cardiac index of 3.2 +/- 0.9 l/min/m2, a mean end diastolic volume of 132 +/- 33 ml/m2 and a mean ejection fraction of 0.53 +/- 0.12. Haemodynamic data was obtained under basal conditions and during intravenous infusion of isoproterenol. The average transvalvular pressure gradient was measured by transseptal catheterisation. The cardiac output was measured by dye dilution and the functional surface area calculated using the Gorlin formula (k = 44.5 for the aortic valve and k = 31 for the mitral valve). Perivalvular leaks were excluded by selective left ventriculography or aortography. The average transvalvular pressure gradients for the aortic valve prostheses (no 19 = 1, no 21 = 4, no 23 = 3, no 25 = 7, no 27 = 8) were 17 +/- 7 mmHg for no 19 and 21, 12 +/- 5 mmHg for no 23 and 25, and 9.7 +/- 2.7 mmHg for no 27.(ABSTRACT TRUNCATED AT 250 WORDS)     

Stentless vs. stented aortic valve bioprostheses: a prospective randomized controlled trial.

AIMS: We sought to assess the haemodynamic profile of the Freedom stentless aortic valve compared with a stented bioprosthesis in a randomized controlled trial using echocardiography. METHODS AND RESULTS: Sixty patients (mean age 73 years) undergoing bioprosthetic aortic valve replacement (AVR) were randomized to either Sorin Freedom stentless (n=31) or Sorin More stented (n=29) valves. The primary endpoints were left ventricular mass index (LVMI) reduction at 6 and 12-months. We also assessed post-operative effective orifice area index (EOAI), aortic gradient and operative time. There were no significant differences in baseline characteristics. The stentless valve was associated with a lower post-operative gradient [PG 17 (12) vs. 31 (13) mmHg, P<0.0001] and greater EOAI [1.1 (0.3) vs. 0.8 (0.2) cm2/m2, P<0.0001]. A highly significant reduction in LVMI occurred by 6 months in both groups, but LVMI was significantly lower in the stentless group [LVMI 119 (39) vs. 135 (30) g/m2, P=0.05]. However, there was continued regression of left ventricular hypertrophy (LVH) in the stented but not in the stentless group, resulting in no significant difference in LVMI at 12 months [119 (36) vs. 126 (31) g/m2, P=0.42]. CONCLUSION: The use of the Sorin Freedom stentless bioprosthesis for AVR results in lower PG and greater EOA when compared with a Sorin More stented valve. This is associated with earlier regression of LVH.     

Aortic and mitral valve bioprostheses. Normal and pathological M mode echocardiographic aspects

The M mode echocardiographic recordings of 52 normal mitral bioprostheses (NMB), 7 pathological mitral bioprostheses (PMB), 30 normal aortic bioprostheses (NAB) and 10 pathological aortic bioprostheses (PAB) were reviewed. In normal bioprostheses a significant correlation was observed between the echocardiographic and the "specified" diameters, the diastolic and systolic slopes and the amplitude of anterior motion of the support. In NMB, the end-systolic diameter of the left ventricular outflow tract depended on the "specified" diameter of the bioprosthesis. Paradoxical septal motion was observed in 78 p. 100 of cases. In PMB, the velocity of anterior leaflet opening was significantly increased (p less than 0.001). The end-diastolic internal left ventricular dimension was also increased (p less than 0.01). A significant correlation was found between left ventricular fractional shortening and maximal leaflet separation (p less than 0.05). Normal septal motion was more common (p less than 0.05). In 5 cases of prosthetic valve dysfunction with mitral regurgitation the maximal leaflet separation was greater than normal (p less than 0.001), the diastolic slope of the support was increased (p less than 0.05) and diastolic vibrations of thickened irregular leaflets were observed. Systolo-diastolic vibrations with chaotic leaflet motion were characteristic of cusp tear and/or eversion. Stratified echos behind a support with reduced leaflet excursion was observed in one case of partial thrombosis: a thickened systolic echo with reduced diastolic excursion was observed in a case of degenerative stenosis. The review of 10 PAB showed a reduced amplitude of systolic excursion of the anterior support in cases of aortic regurgitation (p less than 0.05). Systolic vibrations of the cusp were not specific and were observed in normal cases. In severe valvular regurgitation mitral and/or septal diastolic fluttering was observed. Systolic excursion of the cusps was reduced in cases of relative stenosis due to an inappropriately small sized bioprosthesis. Thickening of the diastolic cusp echos was observed in cases of degenerative stenosis. Ventricular dilatation and reduced septal and free wall motion were dysfunction.     

Multiple valve replacement increases the risk of reoperation for structural degeneration of bioprostheses.

BACKGROUND AND AIM OF THE STUDY: The study aim was to analyze the results of reoperations for structural degeneration of bioprostheses, and to define a high-risk population for reoperative procedures. METHODS: A series of 524 consecutive patients who had undergone a first reoperative replacement for a failed bioprosthesis between 1978 and 1998 was reviewed retrospectively. The reoperative procedure comprised 363 single valve replacements, and 161 multiple valve replacements. During the original procedure, 648 bioprostheses had been implanted in the mitral (n = 403), aortic (n = 220) and tricuspid (n = 25) positions. RESULTS: The mean interval between the original procedure and reoperation was 8.8 +/- 3.3 years. Tissue valve failure was revealed by recurrence of cardiac insufficiency in 70% of cases. The overall early mortality rate was 8%, but early mortality rates for elective single mitral and aortic reoperative valve replacements were only 3.9% and 4%, respectively. Early mortality following reoperation for single and multiple valve replacement was 6.0% and 12.4% respectively (p = 0.02). Other significant multivariable predictors for early mortality were old age (p = 0.003), NYHA functional class (p = 0.007), presence of ascites (p = 0.02) and reoperation performed before 1988 (p = 0.013). CONCLUSIONS: The risk of reoperation for structural degeneration of bioprostheses is acceptable for elective single reoperative valve replacement as opposed to multiple reoperative valve replacement. This may limit the use of bioprostheses during the original procedure when multiple valve replacement is required.     

Long-term results after aortic valve replacement with four different prostheses

The long-term results after implantation of isolated aortic ball and disc prostheses were studied. The Starr-Edwards ball valve type 1200 was first used in 80 patients, thereafter type 2300 was used in 173, later the Björk-Shiley and the Lillehei-Kaster disc valves were implanted in 99 and 97 patients according to randomization. The surviving patients with the oldest ball valve were examined after 4.7 and 6.7 years on an average, the others after approximately 2.5 and 4.5 years.The early mortality rate was 15%, and did not differ between the four groups. Even the late mortality rate was quite similar in the patient groups, the five-year survival rate being 65% in patients with ball valves and 68% in those with disc valves, as estimated with the actuarial method.The average reduction of heart size was moderate and quite similar in the four groups, most pronounced in patients with isolated aortic valve involvement. The reduction was greater in patients who received larger rather than smaller valves of all types.Aortic valve replacement resulted in a considerable clinical improvement in patients with all valve types; it corresponded largely to one functional group according to the NYHA classification. The heart size reduction and functional improvement was most moderate in patients with smaller ball valves, which could be anticipated from higher peak systolic gradients than across the other valves used. No significant differences appeared between patients with the larger valves of the four types.The initial improvement, as recorded either by reduction of heart size or increase in functional capacity, had reached its maximum at the first follow-up examination in most patients.The preoperative myocardial function appeared to be the limiting factor which determined what late results could be obtained regardless of the type of valve implanted. The results therefore indicate that more can be achieved by earlier valve replacement than by improving the prostheses.     

Actuarial versus actual freedom from structural valve deterioration with the Carpentier-Edwards porcine bioprostheses.

BACKGROUND: The clinical performance of porcine bioprostheses for valve replacement surgery has been evaluated for over three decades by actuarial analysis as the standard for reporting time-related results. The incidence of structural valve deterioration (SVD) is used for the selection of prostheses for various subsets of patients. Actual or cumulative incidence analysis may provide a superior method to determine durability of bioprostheses. OBJECTIVE: To compare actuarial versus actual methodology in determining the durability of porcine bioprostheses for aortic (AVR) and mitral valve replacement (MVR). PATIENTS AND METHODS: Carpentier-Edwards porcine bioprostheses were implanted between 1975 and 1995 in 2237 AVR and 1582 MVR. The mean age for AVR patients was 65.4+/-12 years and for MVR patients 61.7+/-12 years. The cumulative follow-up for AVR was 14,810 years (mean 6.6+/-4.7) and for MVR 9718 years (mean 6. 1+/-4.5). RESULTS: For AVR the actual freedom from SVD was 87.4+/-2. 0% and 95.6+/-1.8% in those aged 61 to 70 years and more than 70 years, respectively; the actuarial freedom was 75.9+/-4.2% and 82. 3+/-7.9%, respectively. For MVR the actual freedom from SVD was 69. 4+/-2.5% and 92.9+/-1.9% for those aged 61 to 70 years and more than 70 years, respectively; the actuarial freedom was 25.5+/-5.7% and 79. 5+/-6.0%, respectively. Predictors of freedom from SVD for AVR were identified as advancing age, falling into the age groups 61 to 70 and those older than 70 years, and intermediate valve sizes; predictors for MVR were advancing age and age older than 70 years. CONCLUSIONS: Comparison of methods of durability assessment revealed that actual freedom from SVD supports porcine bioprostheses for AVR in patients more than 60 years of age and for MVR in patients more than 70 years of age. This evaluation with experience to 15 years supports the indications for use of porcine bioprostheses.     

Suitability of stentless bioprostheses for combined replacement of the aortic valve and ascending aorta.

BACKGROUND: The Edwards Prima stentless valve (EPSV) is a bioprosthesis made of the porcine aortic root which, owing to its versatility, may be implanted with different techniques depending on the underlying disease. The aim of this study was to demonstrate the usefulness of the EPSV implanted as a miniroot in patients with disease of the aortic valve and ascending aorta. METHODS: Between January 1998 and July 2002, 91 patients (mean age 67 +/- 7 years) underwent combined replacement of the aortic valve and ascending aorta with an EPSV for aortic stenosis (n = 12), incompetence (n = 45) or mixed disease (n = 26); all had aneurysmal dilation of the ascending aorta and 8 had an acute aortic dissection. The EPSV was implanted using the miniroot (or inclusion) technique and by extending the aorta with a tubular graft; aortic arch replacement was required in 5 patients. Hospital survivors underwent clinical and echocardiographic follow-up at 6 and 12 months and yearly thereafter. RESULTS: The hospital mortality was 11% (10 patients). Causes of death included stroke (n = 3), septic shock (n = 3), myocardial infarction (n = 2), and low output syndrome (n = 2). The mean follow-up of the 81 discharged patients was 16 +/- 13 months and was 100% complete; there were 6 late deaths due to non-cardiac causes. All patients presented with clinical improvement (95% are in NYHA functional class I) with low transvalvular gradients and significant regression of left ventricular hypertrophy at two-dimensional echocardiography. CONCLUSIONS: The EPSV used as a miniroot has proved to be a valid option in patients requiring simultaneous replacement of the aortic valve and ascending aorta. Due to the limited information available on the long-term fate of the porcine aortic valve and root, the use of this device as a miniroot should presently be limited to elderly patients.     

Long-term survival following aortic valve replacement.

Study was made of 95 survivors of aortic valve replacement during the early years of this procedure (1964 to 1970). The average follow-up time was 50.2 months. Survival was not related to hemodynamic parameters, such as cardiac index or left ventricular pressure, and did not appear to be influenced by the type of preoperative valve lesion. A history of angina pectoris and a New York Heart Association Class IV grouping were associated with shorter survival. Associated coronary artery disease was a leading cause of death in those patients surviving less than 2 years and angina pectoris the leading cause of morbidity in the long-term survivors. Sudden death occurred in five patients. Once a patient survived 36 months after the operation, the prognosis was excellent.