Ball Variance Research Articles

The dawn of surgical treatment of aortic insufficiency.

The dawn of surgical treatment of aortic insufficiency.

A thirty-nine-year survival with the Starr-Edwards mitral valve prosthesis

We report a case of a 57 year-old woman with Starr-Edwards model 6120 mitral valve replacement and Kay-Shiley bioprosthetic tricuspid valve replacement in 1968 at Niguarda Hospital in Milan. The mitral caged-ball has proved its excellent durability and its good hemodynamic performance in many patients, even if subject to high tendency to thrombosis. In literature there is no evidence of durability of this prosthesis longer than 35 years. Our patient after 39 years from mitral valve replacement lives a happy and fulfilling life (NYHA II), with no evidence of hemolysis, ball variance, symptomatic embolization or major bleeding.

43.3-Year Durability of a Smeloff-Cutter Ball-Caged Mitral Valve

Extended durability of mechanical heart valves has been documented for many years. We describe a case of a ball-caged mechanical valve implanted 43.3 years previous to developing valve dysfunction. The patient presented with both prosthetic valve stenosis and insufficiency. This Smeloff-Cutter valve (Cutter Laboratories, Berkeley, CA) in the mitral position was dysfunctional due to lipid absorption, which resulted in ball variance and concomitant pannus growth prevented optimal seating of the ball in its cage. This is the longest length of time in which a Smeloff-Cutter mechanical valve has been originally implanted.

A Starr-Edwards Mitral Prosthesis after 44 Years of Good Performance

The Starr-Edwards caged-ball prosthesis has been widely used to replace cardiac valves. The Model 6120 mitral prosthesis was introduced on the market in 1965 to reduce the high incidence of ball variance and thromboembolism of the previous model. We report the case of a Starr-Edwards Model 6120 which had been in place for 44 years and was still well functioning with no apparent structural damage.

Late Re-operation for Aortic and Mitral Starr-Edwards Ball Valve Prostheses

Starr-Edwards ball valves removed more than 15 years after implantation were retrospectively investigated macroscopically. Eight patients required re-operation. Valve models used in the initial operations were a non-cloth-covered valve in 2 patients and a cloth-covered valve in 6. Two patients had replacement of an aortic ball valve (model 1260 and model 2320) and 6 underwent mitral valve replacement (model 6120 in one, model 6320 in 5). The mean time to re-operation was 23.0 +/- 4.8 years after implantation. Cloth wear causing significant hemolysis was observed in all cloth-covered valves, regardless of valve position. Autologous tissue growth was noted on the orifice ring and struts in both aortic and mitral prostheses. Thrombus formation was not found in any of the valves. Ball variance in silicone rubber balls was mild in the non-cloth-covered valves, even in the aortic position. The most significant problem with the cloth-covered ball valve was cloth wear. Cloth wear should always be considered when 15 years or more have passed since valve implantation. Significant hemolysis, elevation of lactate dehydrogenase values, and echocardiographic detection of transvalvular regurgitation are diagnostic of cloth wear, and are indications for replacement of a cloth-covered ball valve.

Incorrect echocardiographic diagnosis in patients with mechanical prosthetic valve dysfunction: correlation with surgical findings

PURPOSE: To identify the rate of occurrence and type of incorrect echocardiographic diagnoses in patients with mechanical valve prostheses. PATIENTS AND METHODS: We studied 170 consecutive patients (73 women and 97 men) with a total of 208 prostheses who underwent surgery for mitral (n = 136) or aortic (n = 72) valve dysfunction between January 1991 and December 1997. Preoperative echocardiographic data were compared with surgical findings. Any major discrepancy between the echocardiographic reports and surgery was judged to be unconfirmed when the preoperative echocardiographic diagnosis was not confirmed at surgery, but the prosthesis was found to be dysfunctioning; and was judged to be erroneous when the preoperative echocardiographic diagnosis was not confirmed, and surgical inspection failed to reveal any other prosthetic abnormality. RESULTS: There were 25 (12%) diagnostic errors. Of the 136 mitral prostheses, there were 9 unconfirmed diagnoses of paravalvular regurgitation (6 had a fibrous tissue overgrowth, 1 had a thrombus with fibrous tissue overgrowth, 1 had endocarditis vegetations, and 1 had a ball variance) and 5 erroneous diagnoses. Eleven diagnostic errors were made in the 72 aortic prostheses: there were 9 unconfirmed diagnoses (paravalvular regurgitation was diagnosed as transvalvular in 7, and transvalvular regurgitation as paravalvular in 2 cases), and 2 erroneous diagnoses. CONCLUSIONS: Although echocardiography has gained great credibility among clinicians, special care should be taken when assessing patients in whom prosthetic valve dysfunction is suspected.

Reduction of ball variance in silicone rubber occluders

all variance was a major cause for concern early in the B use of heart valves with silicone rubber occluders [l, 21. Ball variance can be defined as the physical changes that can occur in vivo accompanying the absorption of simple and complex plasma lipids. The changes are manifested in several ways, including discoloration, weight gain, wear, swelling, and fissuring. Valve function can be compromised by reduced occluder mobility, or by impaction or loss of the occluder. The SCDK and the Smeloff-Cutter (S-C) valves are double-cage ball valves in which the ball passes through the orifice of the valve, with the equator of the ball essentially occluding the valve orifice. Ball variance is of particular concern because the relationship of the diameter of the ball to that of the orifice must be maintained to assure optimal valve function. Clinical evidence of ball variance was reported in about 2.5% of the SCDK and in about 1% of the early model S-C valves. Because of the relatively low incidence of variance, we believed that both chemical and physical or environmental factors are involved in the development of ball variance. A major factor appears to be aberrant flow patterns in the prosthesis. Data on early Starr-Edwards valves showed that variance occurred only in the aortic position, where turbulence and impact forces were relatively great, and usually were associated with implantation problems, whereas paired mitral implants showed no variance [2]. On this basis, the problem was approached from several angles.

Late ball variance with the Model 1000 Starr-Edwards aortic valve prosthesis: Risk analysis and strategy of operative management

The first generation of aortic ball-valve prostheses, used until 1965, was associated with poppet damage owing to fatty infiltration of the silicone rubber ball, a phenomenon termed ball variance. For the Model 1000 Starr-Edwards valves, almost all cases were discovered before 8 years. However, a review of our patients still at risk with the original valve and poppet, prompted by other recent reports of late ball variance, has shown that severe variance can exist up to 20 years after implantation. There is a relationship between the year of valve implantation and the timing and severity of ball variance for the overall series of patients surviving operation, but for the subgroup currently at risk the sample sizes are too small to detect any difference, if one still exists. Only three of 12 patients in the current subset were found to have severe variance. Simple ball change has been the operation of choice. Prophylactic reoperation is not indicated in the current subset, but patients require careful follow-up and should be considered for reoperation should symptoms develop.

Infection within a degenerated starr-edwards silicone rubber poppet in the aortic valve position

Infiltration of the silicone rubber ball of early model caged-ball prosthetic valves by serum lipids caused changes (ball variance) which often resulted in regurgitation, stenosis or embolization of the poppet. 1 Changes in manufacturing of the poppet in 1965 have almost eliminated ball variance. 2 We describe a patient who had a bare-strut caged-ball aortic valve prosthesis that functioned for 18 years and was electively removed for recurrent infection associated with a variant ball.

Prosthetic valve reoperations

Population characteristics and survival factors are presented for 89 reoperations (eight referrals) from 1,445 valve replacements performed over 17 years at the Columbia-Presbyterian Hospital. There were three basic categories of indications leading to reoperation: valve-related systemic disease (infection, embolism, hemolysis), valve-related insufficiency (paravalvular leak, ball variance, homograft retraction), and valve-related stenosis (thrombosis, pannus, homograft obstruction). The leading indication for reoperation among aortic, mitral, and double valves was systemic disease (43 of 83—52 percent); tricuspid reoperations were most frequently performed (five of six—83 percent) for valve-related stenosis. The over-all early mortality rate was 19 percent (17 of 89) and varied with the reoperative site, indication, and urgency. In general, survival was lower in atrioventricular than aortic prosthetic reoperations. High-risk reoperations (N = 37, mortality rate 43.2 percent) occurred in the presence of prosthetic infection or prosthetic stenosis. When reoperations were performed urgently in the high-risk group, the mortality rate increased to 67 percent (16 of 24). However, in the absence of infection or stenosis, regardless of the urgency of reoperation, the mortality rate was only two percent. Five-year survival rates for low-risk reoperations were—aortic 69 percent and mitral 55 percent. Morbidity parameters among survivors did not differ from initial valve replacements. It appears that prosthetic valve reoperations can be performed with risks equal to the original operation except in the presence of subacute prosthetic infection or end-stage prosthetic stenosis.

Prosthetic aortic valves. Indications for and results of reoperation.

During a 15-year period from January 1962 through December 1976, 42 patients who had undergone a previous aortic valve replacement underwent reoperation. The mean interval between operations was 4.4 years. The indications for reoperation were aortic regurgitation resulting from mechanical malfunction (12 patients), ball variance (15 patients), perivalvular leaks (five patients), prosthetic stenosis (eight patients), anemia (one patient), and recurrent emboli (one patient). The indications were characteristic of a specific valve series. The most common reoperation was aortic valve replacement (29/42), which had a 10.3% operative mortality. Poppet change (10/42) carried a 10% operative mortality and no operative deaths followed suture closure of perivalvular leaks. Eighty-eight percent of patients alive six months after reoperation were New York Heart Association functional class 1 or 2. At last follow-up, 95% of surviving patients were still functional class 1 or 2, with a mean cumulative survival of 4.7 years after reoperation. This experience demonstrates that those patients surviving long enough to undergo reoperation can expect a reasonable operative risk, long-term survival, and excellent clinical improvement.

Non-cloth-covered caged-ball prostheses: The second decade

The Starr-Edwards Models 6120 mitral and 1200/60 aortic valves are caged-ball prostheses with cloth-covered sewing rings and bare-metal struts. Introduced in 1965, they have been in continuous clinical use longer than any other currently available heart valve prostheses. Late results with this valve are analyzed and compared with recent series employing other current valve prostheses. One hundred thirty-four mitral 6120 prostheses were inserted at the University of Oregon Health Sciences Center from 1965 through 1977, with 118 operative survivors followed for a mean of 5.4 years. Twelve-year survival rate (+/- standard error) was 50 (+/-8) percent. Twelve percent of late deaths were valve related. Eighty-eight (+/-5) percent of valves were still in place at 12 years. The embolic rate was 5.8 (+/-1.0) percent per patient-year for all emboli and 2.2(+/-0.6) percent per patient-year for serious emboli. Two hundred forty-nine operative survivors among 282 patients undergoing aortic valve replacement during the same period of time were followed for a mean of 4.3 years. Twelve-year survival was 61 (+/-6) percent and the removal-free rate was 92(+/-5) percent. Six percent of late deaths were valve related. Embolic rates were 5.0 (+/-.7) percent and 1.8 (+/-.4) percent per patient-year for all emboli and serius emboli, respectively. Structural failure, specifically ball variance, was not encountered with this prosthesis. Ninety percent of 10 year survivors are in N.Y.H.A. Functional Class I or II. There was one anticoagulant-related death in 1,698 patient-years of follow-up. The current non--cloth-covered caged-ball valves provide unquestionable durability and well-documented results into their second decade of use. They provide a base line for comparison with newer prostheses and offer a valid, current choice for both aortic and mitral valve replacement.

Ball variance and fracture of mitral valve prosthesis causing recurrent thromboemboli

This report documents the ninth case of ball variance in a Starr-Edwards Model 6000 mitral prosthesis occurring 10 years, 9 months after implantation. It is the fourth case of fracture of a mitral ball of any type. As this case illustrates, the presence of ball variance in the mitral position may be subtle. One must carry a high index of suspicion if the diagnosis is to be made and treatment undertaken before catastrophic events take place. The incidence of ball variance is likely to increase with the length of implantation. We recommend surgical replacement of the defective prosthesis immediately upon confirmation of diagnosis.

Ball Variance in a Harken Mitral Prosthesis: Echocardiographic and Phonocardiographic Features

A case of ball variance in a caged-ball prosthetic valve is presented, illustrating the echocardiographic and phonocardiographic features. The swollen silicone ball was observed on echocardiographic studies to have diminished motion and to incompletely open within its cage. On phonocardiographic studies, the Q-S1 interval was prolonged, and no opening sound could be recorded. These noninvasive techniques may be helpful in predicting the need for replacement of prosthetic valves that have silicone rubber balls.

Clinical experience with the Smeloff-Cutter aortic valve prosthesis: An 8-year follow-up study

A total of 46 patients who survived aortic valve replacement with the present model Smeloff-Cutter prosthesis between 1968 and 1973 were followed up postoperatively. All patients received oral anticoagulant therapy. The average age at implantation was 44 ± 13 (mean ± standard deviation) years; 36 patients were male and 10 were female. The valve damage was caused by rheumatic disease in 19 (41 percent), infective endocarditis in 14 (30 percent), congenital heart disease in 7 (15 percent) and other factors in 6 (13 percent). Late death occurred in eight patients (17 percent). All available patients were followed up until December 1976. During the 8 years of follow-up study, seven patients, including four heroin addicts, had postoperative endocarditis (15 percent); five of the seven had cerebral involvement, possibly from septic emboli. Four patients were reoperated on; three had active endocarditis and one had a high transvalve pressure gradient. The mean follow-up time was 4.9 years per patient. Of the 38 living patients, 33 have functional improvement and are still being followed up. Only one patient had a bland embolism to a systemic artery. No ball variance or other types of material failure have been detected. Although the chronic aspects of valve disease remain after prosthetic valve replacement, the Smeloff-Cutter aortic prosthesis deserves strong consideration when selecting a rigid prosthesis for aortic valve replacement.

Computer-assisted detection of prosthetic aortic heart valve dysfunction

Computer-assisted analysis of phonocardiograms from 20 Starr-Edwards (SE)-1000 series prosthetic aortic valve patients is described. Six patients had a normal valve (implanted <1.5 years), and 14 had documented prosthetic dysfunction as a consequence of ball variance. Two diagnostic aids were evaluated and compared for their usefulness in the detection of SE-1000 series aortic ball variance: (1) a new technique involving the cross-correlation of consecutive prosthetic aortic opening sounds, and (2) the calculation of an aortic opening to aortic closing prosthetic sound intensity ratio. The cross-correlation was found to be less effective (32% positive diagnosis) than the opening to closing sound ratio (72% positive diagnosis).

A thirteen-year review of the Magovern-Cromie aortic valve

A review of 375 cases of aortic valve replacement with the Magovern-Cromie sutureless prosthesis demonstrated a 43 per cent survival rate 10 to 13 years following the operation. Of the 308 patients surviving zero to 30 days, 238 patients are alive after one to 14 years. A total of 70 patients (22 per cent died during the 14 year follow-up period. The actuarial survival rate of all patients at risk was 64 per cent at the fifth year and 51 per cent at the tenth year. For those patients who lived at least one year after surgery, the probability of survival was 84 per cent and 70 per cent at 5 and 10 years, respectively. These results compare favorably with reports of up to only 8 years with the Smeloff-Cutter and Starr-Edwards prostheses. There was only a 1.5 per cent incidence of perivalvular leak with this method of fixation, and no valve has migrated. Ball variance has not occurred with any valve inserted since 1964, and the incidence of thromboembolism with the Model A4 prosthesis is 2.4 per cent. Improvement in results depend on reduction of thromboembolism, lessening of late and operative morality rates, and by earlier operative intervention to reduce the late deaths from cardiogenic factors.

Late follow-up of ball-valve prostheses in the descending thoracic aorta

Clincal and hemodynamic observations are reported in a group of five patients with free aortic regurgitation treated with insertion of a ball valve prosthesis in the descending aorta. Long-term follow-up ranging from 13 to 23 years illustrates the durability and biocompatibility of the valve and the validity of the concept that a moving prosthesis can function for indefinitely long periods of time. The prolonged survival of these patients at a normal level of activity without congestive failure is strong evidence of the efficacy of the prosthesis even though it did not entirely control all of the aortic insufficiency. All patients showed remarkable improvement of their symptoms from 11 to 21 years after surgery. Four of them have required complete correction of the aortic insufficiency with one postoperative death due to low output syndrome. The valves which have remained in place after insertion of a subcoronary valve are functioning well for 3 to 6 years. There was no evidence of hemolysis, valve malfunction, ball variance, or thrombbosis in any of these patients. The evolution of the technique made it possible to minimize complications which, it should be pointed out, were usually associated with faulty methods of insertion. These patients would appear to represent the longest period of insertion of any valvular prosthesis.

The sutureless aortic valve prosthesis: experience with and technical considerations for replacement of the early model.

Reoperation was performed in seven (16%) of 43 patients with early models of Magovern sutureless aortic valve prostheses, because of thromboembolism and ball variance. All patients survived reoperation with no major complications. Removal of the sutureless prosthesis was not difficult when an insertion tool of proper size was used. A scarred annulus remained which was favorable for the suturing of a new prosthesis. The incidence of disabling thromboembolism (42%) and poppet failure (21%) is high with these early models. When these complications occur, replacement of the prosthesis is recommended to prevent death or recurrent embolic episodes.

Clinical evaluation of aortic and mitral valve prostheses

The clinical follow-up for a large number of patients with aortic and mitral valve prostheses is now the responsibility of the general internist and cardiologist, particularly those physicians who recommended operation. Proper follow-up of patients with prosthetic heart valves can be performed only if the physician is aware of the "natural history" of the patient following valve replacement as well as of the common complications associated with cardiac valve prostheses. This article discusses the hemodynamic changes which follow cardiac valve replacement, complications associated with valve replacement (congestive heart failure, suture disruption, "ball variance," thromboembolism, hemolysis, cardiomyopathy, etc.) and simple clinical means of detecting these complications. Some special techniques which may be useful in diagnosing complications of prosthetic cardiac valve malfunction are described. It is emphasized that the physician should not consider the patient "cured" once he has undergone cardiac valve replacement, but rather should consider him to be the subject of meticulous long-term medical care.