Current status of the Beall, Bjork-Shiley, Braunwald-Cutter, Lillehei-Kaster and Smeloff-Cutter cardiac valve prostheses

Streptokinase treatment of a thrombosed Björk-Shiley prosthesis in the aortic position

Dysfunction of a mechanical prosthetic valve caused by thrombus formation is usually treated surgically. A patient with a thrombosed Björk-Shiley valve in the aortic position was treated successfully with intravenous streptokinase. The considerable improvement in the patient's clinical condition and the phonocardiographic, echocardiographic, and cinefluoroscopic evidence of normalisation of prosthetic valve function established the efficacy of thrombolytic therapy of a thrombosed prosthetic valve in this patient.

Clinical results of titanium retinal tacks with pneumatic insertion

We used titanium retinal tacks inserted with a pneumatic instrument for retinal fixation in 11 operative procedures in ten eyes with complicated retinal detachments. Titanium was selected for permanent implantation because of its documented biologic tolerance. No intraoperative or postoperative complications related to the tacks were encountered. Three tacks, one 0.7 mm in length and two 1.6 mm in length, became dislodged postoperatively; 50 permanently implanted tacks, each 1.6 mm in length, remained in place after a mean follow-up of five months. Retinal reattachment at the end of the follow-up period was achieved in eight eyes and useful visual function was obtained in three eyes. Titanium retinal tacks are useful when immediate retinal fixation is required either temporarily or permanently to prevent retraction and detachment of the retina until adjunctive diathermy, cryopexy, or photocoagulation becomes effective.

Echo-phonocardiographic evaluation of the Björk-Shiley mitral prosthesis

Ninety patients were studied with combined echophonocardiography after Björk-Shiley disc prosthetic mitral valve replacement. They were evaluated every 6 months (mean follow-up 6 years). Nine cases of left ventricular (LV) failure and 6 cases of prosthetic malfunction (5 paravalvular leaks and 1 thrombosis) were detected; 1 case was confirmed at necropsy and the other 5 cases were surgically verified and repaired. The following measures of prosthetic malfunction were evaluated: opening and closing velocity, maximal amplitude of the prosthesis, septal motion 6 months after operation, LV diastolic diameter, protodiastolic hump, variations during same record of the interval between aortic valve closure sound to the phono and mitral valve opening to the echo, and interval between aortic valve closure sound and maximal excursion of the LV posterior wall. All measures studied were useful for detecting prosthetic malfunction, but 2 are more useful in individual cases: variations of the interval between second heart sound and mitral valve opening and the interval between the aortic valve closure sound and LV posterior wall motion. These 2 intervals also allow discrimination between normal function, prosthetic malfunction and LV failure.

Evacuation of calcific valvular debris using a standard Ellik evacuator

A simple but effective technique is described for removing calcific and other debris following aortic and mitral valve replacement. This technique uses an Ellik evacuator , which is readily available in most operating rooms. An 11-year experience is presented, documenting the efficacy of this method in several hospitals.

Bileaflet, tilting disc and porcine aortic valve substitutes: in vivo hydrodynamic characteristics

The St. Jude valve is a new bileaflet disc cardiac valve prosthesis designed to avoid some of the hemodynamic drawbacks of other prostheses. The in vivo flow characteristics of the St. Jude aortic valve (42 patients) were studied and compared with those of three other commonly used aortic prostheses. Björk-Shiley (12 patients), Hancock (27 patients) and Carpentier-Edwards (15 patients). The studies, performed 24 to 48 hours after surgery, included measurements at rest and during augmentation of valve flow by infusion of isoproterenol. The mean performance index for valves of all sizes is higher for the St. Jude than for either porcine valve, both at rest and during isoproterenol infusion (p less than 0.05). Utilizing data both at rest and with isoproterenol, the relation of valve flow and mean systolic gradient for each size of St. Jude valve (19 to 25 mm) indicates the occurrence of small increases in gradient (5.3 to 8.2 mm Hg) as valve flow increases, ranging from 161 to 436 ml/systolic X min. A direct comparison of valve flow and gradient data for all size 25 and 23 mm prostheses at rest indicates a tendency for a lower mean systolic gradient in both mechanical valves than in either porcine valve (p = 0.07). With isoproterenol augmentation of valve flow in 25 mm valves, the gradient is less (p less than 0.05), and the effective orifice area and performance index are larger (p less than 0.05) for the St. Jude than for either porcine valve.(ABSTRACT TRUNCATED AT 250 WORDS)

Prosthetic heart valves: a review

There are a number of difficulties inherent in the analysis of such a large and diverse quantity of data. In a substantial number of clinical trials, there is no significant effort made to evaluate prosthetic performance as a function of preoperative cardiac anatomy. Hemodynamics have not been systematically studied in relation to preexisting left ventricular size, shape, or configuration, mitral annular orientation, or left atrial size. Postoperative anticoagulation protocols vary from one institution to another and occasionally within study groups themselves. Less tangible variables such as alteration in surgical technique over time and differential familiarity of cardiovascular surgeons with the prostheses employed are chronic problems in any study of this sort. Perhaps the greatest variable in evaluating the postoperative performance of valvular prostheses over the past 20 yr is the radical improvement in techniques of intraoperative myocardial preservation. Notwithstanding, comparisons are possible within the confines of certain criteria. The caged ball value remains in use after 20 years of clinical experience. It has sustained the greatest number of modifications, probably because it has been the most extensively studied. Hemodynamics are adequate although its centrally obstructed design is responsible for increased turbulence, hemolysis, and neointimal proliferation, particularly in the aortic position. The device has been shown to be durable with virtually no reports of ball variance since the alteration of the silicone curing procedure in 1965. Thromboembolic rates are acceptable in the anticoagulated patient while prosthetic thrombosis is not a grave threat in the non-close clearance device. Incidence of endocarditis is not particularly different from that associated with all nonbioprosthetic valves, although there is a much greater published volume of clinical experience concerning recognition and treatment of late prosthetic valve endocarditis in patients with caged ball valves than there is for any other replacement device. Perhaps the most serious disadvantage to caged ball design is its size. Its large spatial requirements have led to anatomic complications in patients with small aortic roots, isolated mitral stenosis, left ventricular hypertrophy, and double valve replacement, among others. Nevertheless, this is still the valve of choice in some centers.(ABSTRACT TRUNCATED AT 400 WORDS)

Hemodynamics alterations induced by isoproterenol and pacing after aortic valve replacement with the Björk-Shiley or St. Jude medical prosthesis

Stress evaluation was carried out in 26 patients approximately 7 months after aortic valve replacement with Björk-Shiley valves (13 patients) and St. Jude medical valves (13 patients). During isoproterenol infusion (0.3 micrograms/kg/min), cardiac output increased by a factor of 1.5 and aortic valve area decreased by 50% for both valve groups, while transvalvular gradients (rest: 7 +/- 2 vs 10 +/- 5 mm Hg, p greater than 0.05) increased by 42 +/- 18 vs 51 +/- 18 mm Hg (p greater than 0.05), i.e., to levels of moderate aortic stenosis. However, during pacing stress these values progressively decreased with rising heart rates. In other postoperative evaluations that included ergometric stress with isoproterenol and pacing, induced hemodynamic changes after aortic valve replacement were predictable and consistent with regard to both direction and magnitude, and they differed characteristically according to the type of stress used. We conclude that no functional differences between Björk-Shiley and St. Jude medical valves can be claimed. Standardized evaluation with isoproterenol is a sensitive stress test of prosthetic valvular hemodynamics. Because of the apparent magnification of residual obstruction after aortic valve replacement, it has advantages over pacing.

Clinical experience with the Smeloff-Cutter prosthesis: 1- to 12-year follow-up

To determine the long-term results of aortic valve replacement with the Smeloff-Cutter prosthesis, the fate of 358 of 459 (78%) consecutive patients was determined 1 to 12 years postoperatively. There were 319 male patients (70%). Mean age at operation was 57 years (range, 15 to 84 years). Aortic stenosis was the dominant lesion in 267 patients (58%) and aortic regurgitation in 133 patients (29%). Fifty-nine patients (13%) had both aortic stenosis and regurgitation. In addition to aortic valve replacement, 93 patients (20%) had coronary artery bypass, 30 (6.5%) had mitral commissurotomy, 23 (5%) had mitral valve replacement, and 41 (9%) had other procedures. Preoperative status by New York Heart Association Functional Class was: Class I, 3 (1%); Class II, 39 (8%); Class III, 148 (32%); and Class IV, 269 (59%). Operative (30-day) mortality was 8.5% (39 out of 459). Functional improvement was obtained in all postoperative survivors: 345 (82%), Class I; 63 (15%), Class II; and 12 (3%), Class III. A perivalvular leak developed in 6 patients (1%) and subacute bacterial endocarditis in five (1%). Actuarial long-term survival was 80% at 5 years and 71% at 8 years. Thromboembolism occurred in 34 patients (9.5%). The incidence of thromboembolism per 100 patient-years for patients receiving no anticoagulants was 5.4; antiplatelet agents, 2.9; and Coumadin (sodium warfarin), 2.6. Major thromboembolism was uncommon in patients on a regimen of sodium warfarin but major morbidity from bleeding was significant.

Entrapment of leaflet of St. Jude medical cardiac valve prosthesis by miniscule thrombus: report of two cases

Two patients with dysfunction of the St. Jude Medical cardiac valve prosthesis, one in the aortic and one in the mitral position, are presented. In both, one of the valve leaflets was jammed by a very small thrombus that fixed the leaflet in a semiclosed position. Neither patient received anticoagulation postoperatively. Because of the pathological findings in these 2 patients, anticoagulation for patients with a St. Jude Medical valve prosthesis is recommended for life.

Retrograde (atrial) dislodgement of a Cross-Jones mitral valve occluder

Fatal atrial dislodgement of a lenticular disc occurred seven years after surgery in a 54-year-old patient, who had had a mitral valve replacement with a Cross-Jones prosthesis, for ruptured chordae tendinae. A marked distortion of the titanium ring reinforced silicone rubber lens disc due to material wear was the cause of this complication. From the literature available to us, atrial dislodgement of a prosthetic mitral occluder has not been previously recorded. We therefore intend to recommend elective replacement of the Cross-Jones prosthesis in all patients who have had their artificial valve functioning for more than five years.

Hemodynamic evaluation of Lillehei-Kaiser and Starr-Edwards prosthesis

The central-flow low profile disc-valve prosthesis has been offered as an alternative to ball- and tissue-valve prostheses. Extensive laboratory investigation with both pulse duplicator and experimental animals has been reported for the Lillehei-Kaster prosthesis. A series of patients receiving this prosthesis underwent postoperative cardiac catheterization to better define the hemodynamic function of this prosthesis in vivo. Because of the variations in reports of hemodynamic data from various institutions, the results of post-operative studies in an earlier group of patients with Starr-Edwards prostheses were used as a standard for comparison. Good hemodynamic function was found with the pivoting-disc prosthesis in all but the smallest valve sizes. Lillehei-Kaster and early model Starr-Edwards prostheses with equivalent tissue annulus dimensions were found to have nearly equal valve areas in vivo in the aortic position. The Lillehei-Kaster mitral valves provided larger areas than Starr-Edwards prostheses in large tissue annulus sizes.

Aortic valve mechanics. Part II: a stress analysis of the porcine aortic valve leaflets in diastole

The stress analysis of the porcine aortic valve leaflets in diastole at 80 mm Hg pressure in-vitro is presented. Incorporation of local geometrical asymmetry, material inhomogeneity, anistropy and non-linearity are applied. The stress theory used is a modified form of the thin membrane stress theory for a homogeneous linearly elastic and orthotropic lamina. Modifications are made so that the Hooke's law constitutive equations of stress may be applied to the inhomogeneous, non-lineary elastic and orthotropic thin (membrane) aortic valve leaflets. Stress calculations are made on the premise that the valve is in pre-transition (i.e. low elastic modulus) in the circumferential direction and post-transition (i.e. high elastic modulus) in the radial direction. It is shown that sigmaCIR less than 1 gm/mm2, and for most of the noncoronary leaflet, 0 less than sigmaRAD less than 30 gm/mm2. The areas of highest stress concentrations are in the areas of mutual leaflet coaptation near the Node of Arantii. A progressive increase of radial stresses from the sinus-annulus edge toward the node is observed.

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.

Late evaluation of patients undergoing valve replacement with the Björk-Shiley prosthesis

This study analyzes 484 patients who survived mitral, aortic, or mitral and aortic valve replacement using the Björk-Shiley prosthesis from January, 1970, through December 31, 1974. Long-term follow-up of 1 1/2 to 6 1/2 years (mean, 3.67 yr) was done on 435 patients (98.2%). Eighty to 85% of the patients have improved noticeably. Thromboembolic problems occurred in 6.9%, representing 1.5 emboli per 1,000 patient-months. Anticoagulant bleeding problems occurred in 6.4% of the patients; late mortality was 15%. Actuarial survival curves showed patients at risk to 6 years having a 79% chance of survival. The same analysis according to preoperative New York Heart Association Functional Classification showed a striking reduction in survival in class IV patients. The Björk-Shiley prosthesis is a good choice for valve replacement today. Earlier diagnosis and treatment are needed to obtain better long-term survival.

The performance of the Braunwald-Cutter aortic prosthetic valve

Four hundred seventy-five patients underwent aortic valve replacement with the Braunwald-Cutter ball-valve prosthesis at two institutions. The early (30-day) hospital mortality was 4.7% for those with isolated aortic valve replacement and 6.9% for the entire group. For the former, 5-year actuarial survival of the hospital survivors was 72 +/- 5.7%; for the latter group it was 71 +/- 4.4%. Eleven patients (5 since the date of follow-up inquiry) have suffered poppet escape, 9 of whom died. The actuarial incidence of known poppet escape is 4 +/- 2.6% at 47 months; when the 5 patients suffering poppet escape since the date of follow-up inquiry are included, with certain assumptions, the incidence is 3.7 +/- 1.14%. The projected probability of poppet escape using all 11 patients is 12.2% at 5 years; the 70% confidence bands of projected probability of poppet escape separate from those of the risk of re-replacement at 61 months. This and other analyses indicate that in general, patients with the Braunwald-Cutter aortic prosthesis should have it replaced 4 1/2 to 5 years after its insertion.

Combined aortic and mitral valve replacement with the Björk-Shiley tilting disc valve prosthesis. Early and late results in 75 consecutive patients

This study evaluates the early and late results of combined aortic and mitral valve replacement with the Björk-Shiley tilting disc valve prosthesis in 75 consecutive patients operated upon during a 6-year-period commencing October 1969. The Delrin disc model Björk-Shiley prosthesis was inserted in the first 20 patients and the pyrolytic carbon disc model in the remainder. The opening angle was increased from 50 degrees to 60 degress and the Teflon sewing ring was designed with two flanges in the pyrolytic carbon disc mitral model. The patient material was characterized by marked cardiomegaly, impaired physical working capacity, hypokinetic central circulation, pulmonary hypertension and a 59% incidence of atrial arrhythmias before operation. Surgery was performed during generalized hypothermia to 30 degrees C and selective coronary perfusion, and the mitral valve was always replaced first. There were no intra-operative deaths, although 7/75 patients (9%) died while in hospital. Twelve patients (16%) died in average 19 (2-59) months postoperatively. Thrombo-embolic complications, which were frequently associated with poor anticoagulation, occurred in 9 patients and were fatal in 4 cases, corresponding to an incidence per patient month of 0.005 and 0.002, respecitvely. This risk was not affected by the type of prosthesis. One patient required operative repair of an aortic paraprosthetic leakage. Clinical improvement was found in 88% of the long-term survivors. The maximal working capacity increased in average 41% over the pre-operative value (p less than 0.001) and cardiac enlargement diminished in average by 22% (p less than 0.001). The incidence of atrial arrhythmias decreased slightly to 48%. Haemolysis was mild and without clinical significance. The actuarial curve indicated a 75% survival rate 3 years after operation.

Systemic embolization of the disk occluder of the Wada-Cutter prosthetic valve. A late complication

The results in 22 patients in the Denver area with Wada-Cutter prostheses were reviewed. There were 14 late deaths, with an average follow-up of six years. Four cases of valve malfunction not related to thrombosis were documented. There were three cases of embolization of the occluder. A survivor is reported. Clinical evaluation of the group suggested new mitral regurgitation to be a sensitive indicator of impending embolization of the occluder. Documentation of valve malfunction warrants valvular replacement.

Choosing a substitute cardiac valve: type, size, surgeon

Certain ideal characteristics of substitute cardiac valves are analyzed for each of the four basic types of available substitute cardiac valves. Of the four, the caged disc prosthesis is the least desirable: it obstructs, it clots and it degenerates. Each of the other three types of substitute cardiac valves has more favorable characteristics. Ideally, the caged ball prosthesis might be limited to patients with predominantly regurgitant lesions because of the problem of prosthetic disproportion. The tilting disc has favorable hemodynamic and wear characteristics, but long-term anticoagulant therapy is essential, as with the caged ball and caged disc types of prosthesis. The porcine xenograft appears to be desirable, but patients with sufficient implantation time (more than 5 years) for proper evaluation are just beginning to be studied and, therefore, final judgment must be reserved. Assuming that valve replacement is to be carried out in a large medical center by a surgical team experienced in this procedure, the results of this operation today are dependent more on the type and size of substitute valve inserted than on the surgeon who inserts the valve. It is therefore important for the cardiologist to become more informed about the various types of prosthetic cardiac valves and to become a member of the team deciding which type and size of cardiac valve are most suitable for his (or her) patient.

In vivo evaluation of the Lillehei-Kaster heart valve prosthesis

In vivo evaluation of the Lillehei-Kaster heart valve prosthesis was performed in 28 patients; 22 had undergone aortic valve replacement and 6 had had mitral valve replacement. Mean pressure gradients ranged from 6 to 53 mm Hg in aortic prostheses; valve area varied from 0.83 to 2.9 cm2. The maximum opening angle of 80 degrees was never reached in this group of patients; opening angles ranged from 57 to 74 degrees without evidence of disc malfunction. There was no correlation between the ratio of effective to geometric valve area and the degree of opening of the disc occluder. Similar results were found in the mitral valve group. Gradients ranged from 6.0 to 12.5 mm Hg and valve area from 1.6 to 2.2 cm2. The maximum opening angle was 59 to 63 degrees. It is concluded that incomplete opening of the disc occluder in pivoting-disc valves is not necessarily a sign of disc malfunction. Lillehei-Kaster valves smaller than 18 mm in internal diameter should be avoided in adults, and outflow aortoplasty for implantation of a larger prosthesis should be used in patients who have a narrow aortic root.