8:30 A.M. BusinessSession (Limited to Members)

Ballroom

8:45 A.M. ScientificSession

Ballroom

1. Comparative Study Between Ball and Disc Prosthesesin Mitral Valve Replacement

ALEJANDRO ARIS,* ALFRED J. FAST,* ALFREDJ. TECTOR,*

ROBERT J. FLEMMA and DERWARD LEPLEY,

Milwaukee, Wisconsin

A total of 196 patientsunderwent isolated mitral valve replacement between November, 1967 andDecember, 1972. From 1967 to 1970, the cloth covered Starr-Edwards metal ballprosthesis was used in 87 patients. Two-thirds received the Model 6600 whilethe remaining one-third received a newer model, 6310, with compositeconfiguration. One hundred, nine patients received the Bjork-Shiley tiltingdisc valve between 1970 and 1972. Computerization of all patients provided a92% follow-up. In order to make fair comparison between the two types ofvalves, only the postoperative period up to 36 months was considered in eachgroup (mean 21 months). Hospital mortality was 25% (21 patients) with The ballvalve, 3.5% (4 patients) with the disc valve. This difference was derivedmainly from the improvement in surgical technique and postoperative careinitiated in 1970 when the ball valve series was concluded. Late mortality was15% (10 patients) with the ball valve and 4.7% (5 patients) with the discvalve. Ball valve thromboembolic complications occurred in 9% (6 patients) and4.7% (5 patients) in the disc valves; while prosthetic enocarditis developed in12% (8 patients) and only 0.9% (1 patient) respectively (p<0.001).Postoperative cardiac catheterization was performed in 1 7 patients. Bothprostheses functioned well, with an equal decrease in pulmonic artery pressuresand capillary wedge pressure. However, the mean decrease in gradient across thevalve was 19.3 mm Hg with the disc prosthesis as opposed to 7.5 mm Hg with theball prosthesis (p <0.05). Quality of life among survivors was improved inover 90% of the patients in both groups. In view of the above results, theauthors feel the Bjork-Shiley valve offers a significant improvement in thelong term outlook of patients requiring mitral valve replacement.

2. Tricuspid Annuloplasty - A Five-YearExperience With 78 Patients

ARTHUR D. BOYD,RICHARD M. ENGELMAN,* O. WAYNE ISOM,*

GEORGE E. REED and FRANK C. SPENCER, New York, N.Y.

Seventy-eight tricuspid annuloplasties (TA) wereperformed for Tricuspid Insufficiency (TI) at the New York University MedicalCenter between January 1968 and July 1973. During this same period ninetytricuspid valve replacements were performed. Sixty-three TA's were performed inpatients having mitral valve procedures and 15 in patients having mitral andaortic valve procedures. TI was not recognized preoperatively in 41% of thepatients having TA's, emphasizing the importance of routine digital palpationof the tricuspid valve. The TI was severe in 25 patients (32%), moderate in 38(49%), and mild in 15 (19%). In 77% of the patients, the right atrial andventricular pressures were elevated at pre-operative catheterization. Thehospital mortality in the 78 patients was 14%.

Digital examination at operation following annuloplasty found a trace ofresidual TI in 14 patients (18%), while the other 64 (82%) had no palpableinsufficiency. Subsequently 5 patients (6%) had a recurrence of significant TI.It seemed significant that in all of these a mitral valve operation wasunsuccessful, resulting in elevated right sided pressures which contributed tothe failure of TA.

Our operative technique for evaluating the tricuspid valve, guidelinesfor choosing between annuloplasty and replacement and our technique forannuloplasty will be discussed. The long-term results in these 78 patients willalso be presented and compared with those in patients having tricuspid valvereplacement.

3. Allograft Cardiac Valves: A View Throughthe Scanning Electron Microscope

JOHN W. HAMMON, JR.,* MICHAEL J.O'SULLIVAN,*

JAMES OURY,* and RICHARD G. FOSBURG, SanDiego, California

The clinical feasibility of implanting cardiac valvular allografts hasbeen well established. Experimental studies have shown subtle degenerativechanges in cardiac allograft valves and have linked them to rejection, traumaand poor preservation,. It was the purpose of this study to examine canineallograft cardiac valves to more accurately assess the changes that occur afterimplantation.

Canine aortic valves were sterilely removed andmounted on dacron covered metal support frames. They were then sterilized byimmersion in nutrient media containing antibiotics. Twenty-five valves wereallowed to stay in tissue culture media two to seven days. Fifteen freshallograft valves were then implanted into the mitral position in mongrel dogs.Valve function was assessed by regular cardiac catheterization andventriculography. Animals were sacrificed at 3, 6, and 12 months. The valveswere tissue cultured and studied with light and scanning electron microscopy.The remaining 10 valves served as controls. Transvalvular gradients averaged 8mm. Hg. and did not increase with implantation time. Ventriculographydemonstrated 1+ insufficiency in 2/15 valves, which was present from the timeof implantation. All fresh valves were viable, by tissue culture, during theperiod of observation. Leaflets became grossly thickened and stiff by one year.Light microscopy demonstrated areas of cell necrosis and fibrous dys-plasiawhich increased with implantation time. Scanning electron microscopy showedthat as implantation time lengthened the surface of the leaflet wasincreasingly irregular with areas of disrupted endothelium. These areascontained collagen fibers which were partially covered with a pseudoendotheliumof platelets, fibrin, red and white blood cells. By one year greater than 60%of the leaflet surface was denuded of endothelium and replaced by thepseudoendothe-lial matrix.

The results of this study suggest thatfresh preserved canine cardiac valvular allografts undergo changes in theirarchitecture after in vivo function. These changes includedisruption of the surface endothelium which is best appreciated with the use ofthe scanning electron microscope. These changes raise pertinent questions aboutthe long-term function of cardiac allograft valves.

4. A Six-Year Study ofGlutaraldehyde-Preserved Hetero-graft Valves

ALAIN CARPENTIER,* A. DELOCHE,* J.RELLAND,* and

CH. DUBOST,* Paris, France

Sponsored by James R. Malm, New York, N.Y.

In March 1968, we introduced the use of Glutaraldehyde as a cross-linkingfactor in the preparation of heterograft valves. Glutaraldehyde markedlyreduced the antigenicity of the graft while increasing the stability of theCollagen.

The first 100 patients operated upon between March1968 and December 1972 have been reviewed. 17 patients had congenital valvularmalformations (7 Ebstein's malformation, 4 Pulmonary Valve Atresia, 3 Truncus,3 Mitral). The remainder had acquired valvular disease. The latter groupcomprised 30 aortic, 19 mitral and 34 double or triple valvular diseases.

The hospital mortality was 6% in the single valve replacement group and14.5% in the multiple valve replacement group. Two cases of acute bacterialendocarditis occurred postoperatively. Only one late death was valve related. 4valve dysfunctions were successfully reoperated at 4, 4.5 and 5 years followingoperation (3 mitrals and 1 aortic). Histological examination revealed theabsence of immunological reaction and scarring. Cusp perforations were presentin all four due to localized areas of collagen degeneration. 77 patients (85%)had excellent valve function. Hemodynamic data is available in 17 patients. Nothrombo-emboic complications were observed.

These results confirm the view that the method of valve preparation andstorage is critical to long term function, as indicated by the low failure ratein the present series compared to previous reports.

5. Long-Term Evaluation of Tissue Valves

MARION ION IONESCU,* BROJESH C.PAKRASHI,*

DAVID A. S. MARY,* IVAN T. BARTER,* andGEOFFREY H. WOOLER,*

Leeds, England

Sponsored by Dwight C. McGoon, Rochester,Minn.

Valve replacement with frame-mounted, three-cusp tissue valves wasperformed in 267 patients (150 aortic, 110 mitral and 7 tricuspid). Autologousor homologous fascia lata was used in 144 patients (follow-up 6-60 months)while 123 had heterologous pericardial valves (follow-up 6-36 months).

Myocardial failure was the main cause ofhospital and late mortality. Infective endocarditis contributed to morbidityand mortality early in the series.

Graft failure occurred in 6.3% of mitralpatients, all with fascial valves. None of the aortic or tricuspid grafts havefailed.

Regurgitant murmurs appeared in 34.5% ofmitral patients (the great majority with fascial valves) but only 9.5% haveincreased in intensity. In the aortic position 9.6% have diastolic murmurs(2.7% with pericardial grafts); 3% have haemodynamic significant regurgitation.

There were 7 thromboembolic episodes (5transient). Anticoagulants were not used.

81.3% of mitral and90.8% of aortic patients are in Grade I (N.Y.H.A.).

There have not been graft relatedcomplications in the tricuspid group.

Results of clinical, haemodynamic,angiographic and experimental studies are discussed.

Fascial valves have performed better inthe aortic than in the mitral position. Pericardial valves, irrespective of thesite of implantation, have shown much better results, in all respects, whencompared with fascial valves.

6. SubannularAneurysm Associated With Acute Massive Aortic Insufficiency

AGUSTIN ARBULU and NORMAN W. THOMS,*

Detroit, Michigan

Since January 1970, we have operated upon twelve patients with acutemassive aortic insufficiency associated with subannular aneurysms. Elevenpatients had recovered from a gram positive acute bacterial endocarditis. Onepatient was operated upon while the infection was still active. Only one hadprevious heart disease. Five were drug addicts. All patients were in functionalclass IV.

At operation we found massive destruction of one tothree aortic leaflets. The subannular aneurysm was located below the junctionof the right and the non-coronary aortic cusps in nine patients. In one, theaneurysm was below the left aortic cusp and two showed two and three subannularaneurysms, respectively. The aneurysms contributed to the massive aorticinsufficiency in all the patients. One aneurysm was calcified. In eightpatients we closed the orifice of the aneurysm with pledgeted sutures and usedthis closure as the seat of the aortic prosthesis. In two of these patients,the sutures pulled through the margin of the aneurysm resulting in aperivalvular leak. One was reoperated upon and died. The other is alive andfree of symptoms. In another patient the pledgeted sutures tore through theannulus which led to a fatal perivalvular leak. In four patients we patched theopening of the aneurysm prior to insertion of the prosthesis; none hadcomplications. Nine patients survived the operations.

We recommend: (1) that the aneurysms be patched rather than simply closedwith pledgeted sutures prior to the insertion of the aortic prosthesis; and (2)that the sutures holding the aortic valve be passed externally and pledgetedfrom outside the aorta.

7. The Treatment of Muscular SubaorticStenosis

WILFRED G. BIGELOW, A. S. TRIMBLE, E. D.WIGLE,*

A. G. ADELMAN,* Toronto, Ontario, Canada,

and C. H. FELDERHOF,* Halifax, NovaScotia, Canada

There have been two principle surgical techniques in common use for thecorrection of muscular subaortic stenosis. One is a transaortic myotomy withlimited muscle resection. The other is a more radical resection through aventricular incision.

Recently mitral valve replacement has been recommended as treatment basedon the observation that the anterior leaflet of the mitral valve contributes tothe ventricular outflow obstruction. Although successful the latter techniquedoes not correct the essential pathology and exposes the patient to a moreserious operation with a permanent threat to his well being.

It wasconsidered timely to review the results from the simpler ventriculomyotomy.Thirty-eight cases from a total of 95 studies were selected for surgery basedon a natural life history study and their response to Propranolol. Trans-aorticventriculomyotomy was carried out with 3 hospital deaths all occurring before1965. There were no deaths in the last 25 operations.

Of 35 survivingpatients 80% have shown symptomatic improvement. Postoperative studies in 19revealed that a successful ventriculomyotomy abolishes the abnormal anteriormitral leaflet movement, the outflow obstruction and related mitralregurgitation. Left ventricular end-diastolic pressure decreased in 15 of 19patients.

Simpleventriculomyotomy with limited resection of muscle is effective in muscularsubaortic stenosis and is indicated in symptomatic patients not responding toPropranolol.

8. More Than Five Years' Experience With theBjork-Shiley Tilting Disc Valve in Isolated Aortic Valvular Disease

VIKING O. BJORK, AXEL HENZE,* and

ALF HOLMGREN,* Stockholm, Sweden

Of 400 consecutive aortic valve replacements, 161 patients were followed2 to 5 years. Early mortality, 5% late accumulated mortality, 10%, was neitherdue to mechanical failure nor thromboembolism. Postoperative results werejudged from 100 aortografic examinations and 90 transseptal catheterizations atrest and exercise. All patients were re-examined, 80 of them twice. Pressureload was eliminated in aortic stenosis and volume load in aortic insufficiency,where congestive heart failure and pulmonary hypertension were eliminated.Clinical improvement was sustained during the entire follow-up as judged byremaining improvement in working capacity and heart volume. Five patientsrequired re-operation for paravalvular leakage. No thromboembolic complicationsoccurred in patients on anti-coagulation. Patients over 60 years of ageencountered the same improvement as younger patients. Hemoglobin concentrationand serum iron was within normal range despite absence of iron substitution.The rheology of the Bjork-Shiley prosthesis is favourable even in smallersizes. Valve replacement is eliminating the volume load without adding apressure load. Due to its non-overlapping disc it combines a minimum ofturbulence and mechanical crushing resulting in low hemolysis.

11:15 A.M. Presidential Address

Lyman A. Brewer, III

A HERITAGE AND A CHALLENGE

*By invitation