Rate Of Valve Failure Research Articles

Does valve size impact hemodynamic, left ventricular mass regression, and prosthetic valve deterioration with a sutureless aortic valve?

ObjectiveTo assess the mid-term clinical outcomes, hemodynamics, left ventricular (LV) mass regression, and structural valve deterioration (SVD) in patients implanted with the Perceval aortic sutureless valve across valve sizes. MethodsData were obtained from a multicenter European trial and a US Investigational Device Exemption trial. Echocardiography data were analyzed by an echocardiography core lab. A mixed-effects regression model was used to assess relationships between hemodynamic outcomes, time from the procedure, and valve sizes. The Valve Academic Research Consortium (VARC)-3 definition for bioprosthetic valve failure was applied. ResultsA Perceval sutureless valve was implanted in 970 patients. The median patient age was 77.8 years, 57.2% were female, the median Society of Thoracic Surgeons predicated risk of mortality was 3.3% (range, 2.1%-6.2%), and 33.4% had a concomitant procedure. The median clinical follow-up was 45.7 months (range, 28.2-76.1 months). Small and medium valves were implanted more commonly in women than in men (16.9% vs 1.9% for small and 55.1% vs 19.5% for medium; P < .001). The mean aortic valve gradients decreased significantly postimplantation and remained stable across all valve sizes throughout the follow-up period. All patients were free from severe patient–prosthesis mismatch (with an effective orifice area/m2 of >0.8). Significant LV mass regression was documented regardless valve sizes, plateaued at -9.1% at 5 years. Freedom from SVD and reintervention were 95.2% and 96.3%, respectively, at 5 years and were independent of implanted valve size (P = .22). The VARC-3 stage 3 bioprosthetic valve failure rate was low, 2.8% at 5 years. ConclusionsThe Perceval valve demonstrated low and stable mean gradients, significant LV mass regression, and low SVD and reintervention rates across all valve sizes.

Safety and reliability analysis for butterfly valves in the offshore oil and gas industry

Valve systems are essential components in piping systems in a variety of industries, including oil and gas to stop and start the flow of fluid, regulate and control fluids, prevent backflows, and provide safety. The safety and reliability of industrial valves is an increasingly critical issue that has been addressed in previous studies. In case of valve failure due to mechanical failure, material corrosion, poor manufacturing and testing, there can be negative consequences including loss of assets, leakage into the environment, and other issues. The objective of this study is to develop a method for measuring the safety and reliability of safety critical butterfly valves by combining safety integrity level (SIL) and failure mode and effect analysis (FMEA). On the basis of operational data, butterfly valve failure rates are estimated. Safe failure fraction (SFF) are calculated at approximately 89% for the valves and converted into SIL2 that meets the end-user requirements.

Optimal emergency shutdown valve configuration for pressurised pipelines

This paper presents the development and testing of a multi-objective optimisation technique for selecting the optimal in-line Emergency Shutdown Valve (ESDV) configurations for high-pressure transport pipelines. Using a real 150.2 km long, 1016 mm i.d. natural gas pipeline operating at 80 bar and 307.24 K as a case study, the optimisation technique is employed to strike the optimal balance between risk reduction, valve failure rate and capital cost expenditure. Starting with defining a set of six important valve and pipeline design characteristics as optimisation variables, Principal Component Analysis is employed to reduce the number of these parameters to three, reducing computational workload, whilst retaining accuracy. The results obtained using the multi-objective optimisation model are presented using scatter plots providing a geometrical visualisation of the set of optimal solutions in the space of objective functions. The findings demonstrate the efficacy of the proposed technique as an effective tool for the decision makers to select the optimal inline ESDV configurations, taking account of the valve type, pipeline overall dimensions, operating conditions, and the fluid composition being transported.

Follow-Up of the Mid-Term Results for Mitral Valve Repair for Rheumatic Mitral Regurgitation

AbstractBackground: Rheumatic mitral valve disease is consider-ably less common in North America and European countries than in developing countries, where rheumatic heart disease remains by far the leading cause of valvular diseases. This study was done to evaluate the midterm results over 10y of mitral valve repair for rheumatic mitral regurgitation in term of survival rate and late valve failure and need of redo surgery.Aim of Study: To record mid term results over 10y of our trail to repair the mitral valve with rheumatic pathology that caused uncoaptation and regurge in the mitral valve with special attention to the evaluation of the number of patients survived, delayed failure of the repair done and need of redo surgery.Patients and Methods: This is a retrospective study from January 2004 to January 2014, one hundred and twenty patients with rheumatic mitral valve disease underwent mitral valve repair in our hospital. Age ranged from 15 to 53 years, 80% patients were female. The lesions were pure mitral regurgitation in 95 (79.1%) patients, predominant mitral regurgitation with stenosis in 12 (10%), and predominant mitral stenosis with regurgitation in 13 (10.8%). Ninty patients (75%) patients were in normal sinus rhythm.Results: Follow-up time ranged from 6 to 120 months, mean 55.4±3.2 months. There were 10 late deaths. Survival at 5 and 10 years was 96.5% and 91.2%, respectively. 25 patients (20.8%) patients had mitral regurgitation during follow-up, and 8 underwent reoperation with no hospital mortality. Freedom from reoperation at 5 and 10 years was 93.5% and 82.7%, respectively. Progression of mitral regur-gitation at 5 and 10 years was 71.4% and 59.3%, respectively. Freedom from all late events at 5 and 10 years was 72.6% and 54.2%, respectively.Conclusions: Mitral valve repair for rheumatic mitral regurgitation is associated with a significant rate of valve failure and reoperation. However, it has a satisfactory survival rate and is a good alternative to valve replacement, especially for young female patients in child bearing period to avoid the life-long risks of a prosthetic valve and anticoagulation related problems.

Mid- to long-term outcomes of bovine jugular vein conduit implantation in Chinese children.

Bovine jugular vein (BJV) conduits are widely applied for surgical reconstruction of the right ventricular outflow tract (RVOT). However, relevant studies of valve failure rates and the related risk factors are limited in China. The aim of this study was to assess the BJV prognosis after medium- to long-term follow-up. Fifty-three hospital patients implanted with BJV conduits from January 2002 to December 2013 were recruited. Patient information and follow-up prognosis were reviewed retrospectively. Conduit stenosis and failure as well as endocarditis were diagnosed. The total person years was 345.5, and the median follow-up time was 6.3 years. Early mortality occurred in two patients, and there was no late mortality. BJV conduit failure occurred in 15 patients (29.4%) due to severe stenosis (n=10), stenosis plus regurgitation (n=3), and regurgitation alone (n=2). The proportion of patients who were free of BJV conduit failure at 1, 3, 5, and 7 years was 98.0%, 85.8%, 76.8%, and 62.1%, respectively. There were nine cases of endocarditis (17.0%). Multivariate logistic regression analysis showed that endocarditis was a significant risk factor associated with BJV conduit failure (OR: 6.735; 95% CI: 1.348-33.647). The durability of BJV conduits was suboptimal after a mid-term follow-up period. Endocarditis was found to be a significant risk factor that accelerates BJV conduit deterioration.

No‐Lead Brass Service Valve Performance in Colorado River Water

In accordance with the Reduction of Lead in Drinking Water Act, no‐lead (&lt;0.25%) brass service valves must now be installed for new connections or as replacements throughout distribution systems. In this study, no‐ and low‐lead (&lt;8%) red brass corporation stops and angle‐meter service valves were evaluated for 10 months using a flow‐through pipe rig with treated Colorado River water. In both no‐ and low‐lead valves, the fraction of tin increased from a minor (&lt;10%) to a major (&gt;40%) element on the wetted interior surface. Corrosion changes were consistent across valve and material types, except for the formation of a white precipitate of lead on the external surface of low‐lead angle‐meter valves and nonwetted fittings. Copper enrichment from potential dezincification was identified in the pack joint fitting crevice of the angle‐meter valves. Changing to no‐lead brass is not anticipated to result in increased service valve failure rates.

Mitral valve repair for rheumatic mitral regurgitation: Mid-term results.

This retrospective study was undertaken to evaluate the midterm results of mitral valve repair for rheumatic mitral regurgitation, in term of survival rate and late valve failure. From January 2003 to January 2014, 97 patients underwent mitral valve repair in our hospital. Age ranged from 8 to 74 years, mean 24 ± 1.4 years; 74 (76%) patients were female. Mean preoperative functional class was 2.47 ± 0.07. Mean preoperative ejection fraction was 59.9% ± 2%. The lesions were pure mitral regurgitation in 79 (81.4%) patients, predominant mitral regurgitation with stenosis in 9 (9.3%), and predominant mitral stenosis with regurgitation in 9 (9.3%). Seventy-one (73%) patients were in normal sinus rhythm. One patient died in the postoperative period, and 8 were lost during follow-up. Follow-up time ranged from 6 to 137 months, mean 58.8 ± 4.2 months. There were 6 late deaths. Actuarial survival at 5 and 10 years was 95.5% and 89.2%, respectively. Twenty-seven (27.8%) patients had mitral regurgitation during follow-up, and 7 underwent reoperation with no hospital mortality. Freedom from reoperation at 5 and 10 years was 94.5% and 82.7%, respectively. Freedom from reoperation or progression of mitral regurgitation at 5 and 10 years was 70.4% and 61.8%, respectively. Freedom from all late events at 5 and 10 years was 68 % and 56.4%, respectively. Mitral valve repair for rheumatic mitral regurgitation is associated with a significant rate of valve failure and reoperation. However, it has a satisfactory survival rate and is a good alternative to valve replacement, especially for young patients, to avoid the life-long risks of a prosthetic valve.

Editorial: Programmable shunts versus nonprogrammable shunts

In this provocative single-institution retrospective review, Hatlen et al.1 report the long-term results of valve survival in a large group of children with programmable valves (PVs) and nonprogrammable valves (NPVs). In this 8-year analysis (with a minimum 2-year follow-up), the authors report on 616 valves, 313 of which were programmable and 303 of which were nonprogrammable. Twelve surgeons contributed patients to the study, but more than 70% of the surgeries were performed by 4 surgeons. Indications for placing PVs varied per surgeon. The authors excluded 43 children with shunts placed for brain tumors and 117 children for whom follow-up data were inadequate. From this cohort, the authors noted that the children receiving NPVs tended to be younger, but the 2 cohorts were otherwise not statistically different. Interestingly, although PVs have been reported to reduce the incidence of proximal shunt malfunction by either preventing slit ventricles or limiting overdrainage, these authors found no difference in the rate of proximal shunt revisions between their 2 groups. Additionally, they found that the NPVs had a 5-year survival rate of 45.8% compared with 19.8% for PVs (p = 0.0005). In the past, it has been suggested that the additional costs incurred by using programmable shunt valves would be offset by the reduction in the number of operative interventions required as a result. This is the first large institutional study to question that supposition. The authors reference the report by Richards et al. (Richards H, Seeley H, Pickard J: Are adjustable valves effective in all ages of patient? Paper presented at the 54th International Conference, Society for Research into Hydrocephalus and Spina Bifida, Vancouver, British Columbia, Canada, July 9, 2010) that corroborates their findings. In long-term follow-up, more complex valve systems may fail at a higher rate than simpler valve systems. However, the authors could have provided more detail about their own reported failures. First, it would be of interest for the authors to tell us how these PVs were found to fail. Were the failures due to obstruction within the valve or to a mechanical failure of the rotor? The Codman PVs with Siphonguard have long been known to have a weak silicone connection between the PV and the Siphonguard component, which sometimes fatigues over time, leading to separation of the 2 components and failure. I have experienced 5 valve failures in this particular valve due to design. Second, the valve failure rate in each group as viewed in Table 3 drops off precipitously between Years 4 and 5 for the PV. Do the authors have any suggestions as to why? In summary, the paper is well written and the authors have controlled for as many variables as they can in a large retrospective review. Their findings are certainly noteworthy. Their conclusion calling for a larger multiinstitutional prospective study appears justified as at least 80% of children requiring shunts will do just fine with an NPV. This current review calls into question whether PVs are really cost effective for the majority of patients. (http://thejns.org/doi/abs/10.3171/2011.11.PEDS11431)

An analysis of check valve performance characteristics based on valve design

Although it had been theorized by nuclear industry valve experts that the two most significant factors in assessing check valve performance were valve type (or design) and operating conditions, until recently, no data was available to support their assumptions. In co-operation with the Nuclear Industry Check Valve Group (NIC), Oak Ridge National Laboratory (ORNL) undertook a review and analysis of check valve failures recorded in the Institute of Nuclear Power Operations’ (INPO) Nuclear Plant Reliability Data System (NPRDS). This study involved the characterization of failures according to several parameters, including valve design (e.g. swing check, lift check). Since the valve design is not inherently included within the NPRDS engineering record for each component in the database, ORNL relied on input from NIC, valve manufacturers and catalogs to supply the missing information. As a result, nearly 60% of the 21 000 check valves listed in the NPRDS component database and 85% of the 838 failures occurring during 1991–1992 were identified according to valve design. This data provided the basis to perform previously unavailable cross-correlations between parameters such as valve design versus failure mode, valve design versus failure discovery method, population/failure distributions by valve design, etc. Performance assessments and predictions based on more specific sets of parameters (as opposed to generic check valve failure rates obtained from standard reference sources that generally ignore the valve design) should result in a significant impact on future nuclear plant operations, including inservice testing (IST) practices, maintenance, and probabilistic risk assessments (PRAs) by providing a means to calculate more appropriate relative (and ultimately absolute) failure rates for check valves.

A 20-year experience with the Hancock porcine xenograft in the elderly

Background. The availability of 20 years of follow-up data on the Hancock porcine valve (Medtronic Inc, Irvine, CA) allows determination of long-term actual and actuarial failure rates in the elderly. Methods. We analyzed outcomes after mitral or aortic valve replacement with the Hancock porcine valve in 491 consecutive patients, comparing actual and actuarial valve failure rates in the elderly (age 65 or older) with those in younger patients. Results. The average age of aortic valve replacement recipients was 68 ± 14 years (N = 243) and of mitral valve replacement recipients, 64 ± 12 years (N = 248). Average follow-up was 7.0 years (1,673 patient-years) for aortic valve replacement and 7.3 years (1,781 patient years) for mitral valve replacement recipients. The median time to reoperation or structural failure was 15.9 years for aortic valve replacement patients and 14.3 years for mitral valve replacement patients. However, few elderly patients survived to 15 years (22% of the elderly aortic valve replacement and 13% of the older mitral valve replacement patients). The 15-year actual reoperation rate was therefore only 10% in the elderly aortic valve replacement compared to 30% in the younger aortic valve replacement patients. For mitral valve replacement, the 15-year actual reoperation rate was 11% in the elderly and 36% in the younger patients. The lifetime reoperation risk (the maximum potential number of patients who might ever undergo reoperation during their lifetime) is the sum of actual survival and actual reoperation rates. The lifetime reoperation risk was 20% or less for elderly aortic valve replacement patients and 18% or less for elderly mitral valve replacement patients. Conclusion. These data suggest that about 1 in 10 elderly patients (65 years or older) receiving a Hancock valve will require reoperation within 15 years and less than one in five will ever require reoperation in their lifetimes.

Mechanical heart valves: Changes in patient survival and valve failure rates

The effect of patient related variables and mechanical heart valve substitutes on survival and valve failure rates was studied in 2,778 patients operated between 1966 and 1986. Of these 48.2% were operated without cardioplegic protection (phase I) and 51.8% thereafter (phase II). Mitral vlave replacement (MVR) was performed in 1,257 patients (phase I: 51.58%, phase II: 48.42%); aortic valve replacement (AVR) in 931 (phase I: 54.78%, phase II: 45.22%) and combined procedures in 590 (phase I: 31%, phase II: 69%) patients. Starr-Edwards valves (SEv) were used in 642, Bjork-Shiley valves (BSv) in 1993, and St Jude Medical valve (SJv) in 143 patients. At 15 years, ‘valve failure’ rate was 32±5, 48.31±6 and 361±3% for all AVR, MVR and AVR with MVR patients respectively. At 22 years, ‘valve failure’ rate was 51% for SEv model A 1200/60 patients and 56% for SEv model M 6120 patients. Valve related events (488) contributed to 13.4% late deaths. Overall incidence of thromboembolism was 10.18%, anticoagulant related haemorrhage 2.92%, valve thrombosis (SEv and BSv only) 1.56%, paravalvular leak 2.58%, endocarditis (PVE) 1.12%, mechanical failure (BSv and SEv A1200) 0.54%, haemolysis (SEv only) 0.4% and reoperations 5% in 2,505 survivors. Mortality following PVE was 56% and that due to thrombosed BSv 35%. Hospital mortality for elective reoperations was 18% in phase I and 5.4% in phase II (p<0.01). During the second decade of implantation cardiac related deaths increased but ‘valve failure’ rate decreased.

Combined Mitral and Aortic Valve Replacement with Bjørk-Shiley Prostheses: Long Term Survival and Valve-related Complications

Between 1974 and 1985, combined aortic and mitral valve replacement (DVR) was performed in 209 patients using Bjørk-Shiley tilting-disc prostheses. Early and late mortality were 9.5% and 10.5% respectively for the entire series. Factors significantly influencing early mortality were: Emergency DVR, preoperative NYHA Class IV, double valve, critical stenosis, and small aortic replacement prostheses. The effect of the latter was augmented by the suboptimal orientation of the implanted prostheses. The overall survival was 74 +/- 4.4% at 12 years; but was only 40 +/- 6.1% at 8 years in patients who were in NYHA class IV preoperatively. Intermittent disc occlusion (DO) and thrombotic disc occlusion (TO), presented as early, anticoagulant related haemorrhage (AH) and prosthetic valve endocarditis (ENDO) as sporadic, and thromboembolism (TE) and paravalvular leak (PVL) as continuous risk factors. Freedom from all known valve-related complications was 77 +/- 4.5% at 12 years (DO, TO, AH, ENDO, TE, PVL: 98%, 97%, 96%, 96%, 88% and 89% respectively). Lethal DO and TO occurred in mitral prostheses. Freedom from reoperation was 95% at 5 and 12 years. Patient-related valve failure rate in this series is comparable with the other series which used mechanical prostheses and is lower than those which used bioprostheses.

Twenty years’ experience with the Model 6120 Starr-Edwards valve in the mitral position

A total of 549 nonconsecutive patients underwent isolated mitral valve replacement with a Starr-Edwards valve prosthesis (Model 6120) at the University of Louvain (Belgium) from 1965 to 1985. Ninety-seven percent of the patients could be traced and only 17 patients were lost to follow-up. Cumulative follow-up totalled 3,130 patient-years. Actuarial and linearized statistical techniques were used to describe the survival and the incidence of valve-related complications (according to stringent criteria). Long-term overall survival rate including early deaths was 79% +/- 0.02% at 5 years, 65% +/- 0.03% at 10 years, and 54% +/- 0.04% at 19 years, with a linearized incidence of late deaths of 3.9% +/- 0.5% per patient-year. The incidence of late valve-related deaths was 1.25% per patient-year. Valve-related complications occurred at the following rates: thromboembolism 3.1% per patient-year, anticoagulant-related hemorrhage 1.08% per patient-year, endocarditis 0.26% per patient-year, reoperation and periprosthetic leak 0.45% per patient-year, and structural failure 0% per patient-year. All valve-related mortality and morbidity were calculated at 4.9% per patient-year and the rate of valve failure (deaths and reoperations) at 1.4% per patient-year. Among 376 survivors, 352 clinical functions could be obtained: 95% of patients belong to Class I or II of the New York Heart Association after operation versus 24% before operation. The study shows the structural durability of the Starr-Edwards mitral valve with a follow-up over 20 years. The Model 6120 valve may be considered a faithful standard.

A comparison of replacement and reconstruction in patients with mitral regurgitation

The factors that make mitral reconstruction an attractive alternative to valve replacement are increased anatomical valve orifice, preservation of the valvular apparatus, improved longevity over porcine xenografts, and no requirement for long-term anticoagulation. In our experience the majority of patients with mitral regurgitation have degenerative valve disease. This comparative series of patients operated on over a 10 year interval includes 72 with replacement and 112 with reconstruction. The average cross-clamp times were 69 minutes for reconstruction and 44 minutes for replacement. The hospital mortalities were 3.6% and 18.1%, respectively. Postoperative valve areas as determined by Doppler echocardiography were 2.69 cm2 for replacement and 2.67 cm2 for reconstruction (p = 0.9). The valve failure rate was 2.0% per patient-year for reconstruction and there were no failures in the replacement group. The reoperation incidence for reconstruction was 20% at 10 years. The remaining patients, although clinically well, had varying degrees of stable, nonprogressive mitral regurgitation. Forty-five percent had mild to trivial regurgitation detectable by echocardiographic studies. The decision between mitral valve reconstruction and mitral valve replacement remains a highly controversial issue. The failure of our data to demonstrate superior valve function for patients with mitral regurgitation undergoing valve reconstruction suggests a need for careful analysis of reconstruction with respect to effective valve orifice and incidence of regurgitation.

Biological versus mechanical valves: Analysis of 1,116 valves inserted in 1,012 adult patients with a 4,818 patient-year and a 5,327 valve-year follow-up

All surviving patients between 18 and 88 years of age receiving biological or mechanical prosthetic heart valves at the Yale-New Haven Hospital from January 1974 through January 1985 were analyzed for thromboembolism, anticoagulation-related hemorrhage, endocarditis, perivalvular leak, valve failure, need for reoperation, late cardiac death, and valve-related death. The rates of these events were analyzed in linear and actuarial terms over the 11 year period. A total of 533 patients received 606 biological valves (328 aortic, 252 mitral, 24 tricuspid, and two pulmonary, consisting of 482 Carpentier-Edwards, 108 Hancock, 15 Ionescu-Shiley, and one other), with a mean follow-up of 2,571 patient-years and 2,935 valve-years. They were compared with 479 patients with 510 mechanical valves (330 aortic, 175 mitral, and five tricuspid, consisting of 178 Starr-Edwards, 166 St. Jude Medical, 164 Björk-Shiley, and two others), which were implanted for 2,247 patient-years and 2,392 valve-years. We found a significantly increased incidence of thromboembolism (p less than 0.001) and reoperation for perivalvular leak (p less than 0.05) in the mechanical valves compared with the biological valves, but a significantly increased rate of valve failure (p less than 0.001) in the biological valves compared with the mechanical valves. The overall analysis comparing total morbidity and valve-related mortality significantly (p less than 0.01) favored the biological valves in the first 5 years of the study and the mechanical valves (p less than 0.001) in the second 5 years of the study. However, the net 10 year results showed no significant difference between the two types of valves. In summary, we found little direct evidence to strongly support the generalized use of one type of valve over another.

The third generation Carpentier-Edwards bioprosthesis: Early results

The current status of valve replacement was reviewed by analyzing six groups of 100 consecutive patients, each receiving the standard Carpentier-Edwards bioprosthesis, the Starr-Edwards valve or the Björk-Shiley valve in the mitral or aortic position and operated on by the same surgeons in the same institution during an identical time frame. Data were evaluated for valve failure, reoperation, thromboembolism and valve-related deaths. Long-term results up to 9 years showed the superiority of bioprostheses over mechanical valves in terms of valve-related deaths and thromboembolic and anticoagulant complications for a similar rate of valve failure. Persistent drawbacks associated with valvular bioprostheses, namely, transvalvular gradients, limited durability and tissue calcification in young patients, led to continual improvements in valve design and preservation techniques and the development of the third generation Carpentier-Edwards bioprosthesis: the supraanular porcine valve and pericardial valve. The supraanular porcine valve was designed with the aim of decreasing the transvalvular gradient, decreasing turbulence, increasing longevity and decreasing calcification. The pericardial valve was designed with the aim of improving hemodynamics in small-sized orifices, improving mounting techniques to avoid fixation sutures at the commissures, achieving a flexible stent and improving preservation. Between July 1980 and October 1984, there were 391 supraanular porcine and 61 pericardial valves implanted. The supraanular valves were used for three purposes: isolated aortic, isolated mitral and mitral valve replacement associated with tricuspid anuloplasty. The pericardial valves were used for isolated aortic valve replacement. Short-term results (1 to 4 years) are presented concerning the clinical use of these third generation bioprostheses.

Valve failure with the Ionescu-Shiley bovine pericardial bioprosthesis: Analysis of 2680 patients

Early reports on the excellent hemodynamic function and low thromboembolic rates of the Ionescu-Shiley bovine pericardial bioprosthetic valve (BPV) encouraged us to use it as our choice for valve replacement in 2680 patients from 1978 through 1983. Analysis of these patients at 5-year follow-up (mean 21.6 months) demonstrated the following important trends. Despite anticoagulation therapy in 48%, thromboembolism occurred in 88 patients for a linearized rate of 1.87% emboli per patient-year and was not time-related. The highest incidence of thromboembolism was in mitral valve replacement (MVR) (2.76% per patient-year). The actuarial freedom from reoperation resulting from valve failure at 5 years was 82% in aortic valve replacement (AVR), 87.1% in MVR, and 92.6% in AVR/MVR. The most distressing causes for reoperation were valve calcification (33 patients, 0.68% per patient-year) and leaflet disruption (11 patients, 0.23% per patient-year). Valve calcification was related to age, small valve size, and AVR position and increased with time, especially at the 4- to 5-year intervals. In patients under 30 years of age, calcification occurred in 18.7% at a mean time of 40.8 months in AVR and in 8.2% at 44 months in MVR, for an overall rate of 11.6%. Over the age of 30 years, it occurred in 14 patients (0.6%) at a mean time of 44 months. Leaflet disruption was not related to age and occurred later in AVR (50 to 58 months) than MVR (1.5 to 61 months). Events increased with time (mean range 37 to 58 months). Because of calcification and leaflet disruption, valve failure causing reoperation has increased significantly at the 4- to 5-year intervals even when valve replacement in patients under 30 years of age is excluded. If this trend continues, the valve failure rate will be exceedingly high on further follow-up. Thus we have limited the use of the BPV to a selected group of patients in whom valve longevity is less important than effective orifice size, thromboembolic rate, and freedom from anticoagulation.

Experience with 813 aortic or mitral valve replacements with the Carpentier-Edwards bioprosthesis: Five year results.

813 patients underwent aortic (AVR) or mitral valve replacement using the Carpentier-Edwards bioprosthesis from 1976 to 1983. Operative mortality was 5.49% for AVR and 4.59% for MVR. Late mortality and complications were classified using criteria described by the Stanford Group. Actuarial survival at 5 years was 87.9% +/- 2.7% for AVR and 91.1% +/- 1.4% in MVR. Thromboembolism occurred at low rates of 0.48% pt yr for AVR and 0.90% pt yr for MVR. 98.2% +/- 0.90% of AVR and 96.9% +/- 1.3% of MVR pts were free from thromboembolism at 5 years. The low incidence of thromboembolism during the early postoperative period played a role in the low rates observed in the complete study. There was no valve thrombosis. Anticoagulation with warfarin was used in 35% AVR and 75% MVR with rates of bleeding complications of 1.20% pt yr and 1.10% pt yr. Overall valve failure rate was 2.04% pt yr at 5 years for AVR and 1.55% pt yr for MVR. Rates of reoperation for tissue failure remained low (0.24% pt yr for AVR and 0.32% pt yr for MVR). The advantage of a low rate of thromboembolism was not outweighed by the specific problems of bioprosthesis at 5 years.

Conservative surgery for mitral valve disease: clinical and echocardiographic analysis of results.

Eighty-five patients underwent mitral valve reconstruction by the Carpentier method from January 1976 to December 1981. Concomitant procedures were performed in 30 patients (aortic valve replacement in 23, coronary revascularisation in six, and tricuspid valve repair in seven). Before operation 76 patients (89%) were in clinical class II or III (New York Heart Association) and atrial fibrillation was present in 50. Thirty-six patients had valvular incompetence, while 26 had pure stenosis. The aetiology was rheumatic in 57 cases and dysplastic in 21. The patients were assessed for clinical improvement, durability of valve repair, thromboembolism, and survival. There was one death, an operative mortality rate of 1.2%, and 63 of 74 patients followed for one to six years were in clinical class I after operation. The actuarial survival was 92% with a 93% incidence of freedom from thromboemboli at five years. Six patients had embolic episodes, four of whom had aortic valve replacement. Three patients had a repeat operation 16-20 months later, a valve failure rate of 6.7%. Nineteen patients with ruptured chordae had postoperative echocardiographic assessment of myocardial and mitral valve functions; the peak rates of dimension changes of the left ventricular cavity (indicative of flow across the mitral valve) fell to normal in most patients, and the left ventricular end-diastolic dimensions decreased significantly from 6.4 (1.53) to 5.09 (1.31) cm (mean and SD)--p less than 0.05. Our results confirm that reconstructive mitral surgery is able to restore and maintain normal valve function in addition to providing satisfactory relief of symptoms.

Medtronic-Hall valve replacement in a Third World population group.

In a twenty-month period, 396 Medtronic-Hall valves were inserted in 341 patients belonging to a Third World population group. Approximately 20% of the patients were given anticoagulants. The total follow-up period was 353 patient years (mean 13 months per patient). Late valve-related mortality was 3.6% patient years (excluding ring leaks) with a valve failure rate (VFR) of 4.0%/patient year. The incidence of thromboembolic complications was 6.8%/patient year while valve thrombosis occurred in 7 patients (2.0%/patient year). Hemolysis was generally subclinical, but 2 patients without ring leaks required transfusion. The initial late results compare favorably with those of St. Jude Medical valve replacement in a similar population group. The supreme test for any substitute heart valve is its successful application in a third world population group because its inadequacies are highlighted by an increased VFR and morbidity.