WEDNESDAY MORNING, MAY 10,1978

8:30 A.M. Scientific Sessions - Ballroom

27. Long Term Clinical and Hemodynamic Evaluation of the Ionescu-Shiley Pericardial Xenograft, Braunwald-Cutter and Bjork-Shiley Prostheses in the Mitral Position

ANAND P. TANDON* and MARIAN I. IONESCU*, Leeds, England

Sponsored by Harris B. Shumacker, Indianapolis, Indiana

Since March 1971, single mitral valve replacement was performed in 220 patients. One hundred twenty-six received glutaraldehyde stabilized Pericardial Xenografts (PX), 52 Braunwald-Cutter (BC) and 42 Bjork-Shiley (BS) prostheses. No attempt was made at randomization. Only patients with BC and BS prostheses were permanently anticoagulated. Hemodynamic studies were performed in 29 patients with PX and in 6 each with BC and BS prostheses at mean periods of 40.2,43.0 and 22.7 months postop respectively. The essential data are summarized below:

Detailed laboratory studies showed no hemolysis in patients with PX and mild red cell destruction in patients with BC and BS prostheses.

The Ionescu-Shiley Pericardial Xenograft in the mitral position has proved to be durable, least thrombogenic without anticoagulants and hemodynamically sound.

There was no significant difference, statistically, between the data recorded from the three groups of patients except for the survival rate of patients with pericardial xenografts and Braunwald-Cutter prostheses.

*By invitation

28. In Vitro Hydrodynamic Performance of Mitral Valve Prostheses at High Flow Rates

S. GABBAY*, D. McQUEEN*, E. L. YELLIN*, R. M. BECKER*

and R. W. M. FRATER, New York, New York

The in vitro hydrodynamic characteristics of 7 currently available mitral prostheses were compared in a pulse duplicator at high-output steady and pulsatile flow with variable stroke volume and pulse rate. Three different mounting diameters (small, medium, large) of each of the following prostheses were studied: Starr-Edwards (SE), Beall (BE), Ionescu-Shiley (IS), Cooley-Cutter (CC), Hancock (H), Bjork-Shiley (BS), Lillehei-Kaster (LK). Effective orifice areas were computed using hydraulic formulas and a performance index (PI), defined as the ratio of effective area to mounting area, was calculated. The results for medium and large size valves in pulsatile flow are tabulated below:

In all valves, effective orifice areas are less than 50% of mounting area and 75% of measured orifice area. At pulsatile flow rates of 9 L/min (comparable to mild to moderate exercise) all valves are mildly to severely stenotic. Among mechanical valves the BS has the least resistance to flow and the SE the most. Of the biological valves the IS is less resistant to flow than the H and only slightly more resistant than

the BS.

Assuming a satisfactory durability and given the favorable characteristics of tissue valves, other than hemodynamic performance, the Ionescu-Shiley heterograft valve appears to be the best mitral prosthesis currently available.

*By invitation

29. Non-Cloth-Covered Caged-Ball Prostheses: The Second Decade

ALBERT STARR, GARY L. GRUNKEMEIER*,

LOUIS E. LAMBERT*, DAVID R. THOMAS*and

EDWARD A. LEFRAK*, Portland, Oregon

This report is concerned with results achieved using current-model non-cloth-covered caged-ball valves since 1965. The data are analyzed in a comparative fashion with other series employing a variety of prostheses.

The actuarial late survival rates with the bare-strut ball valves were the same as those achieved with all mechanical and tissue valves, i.e., 80% at 5 years and 60% at 10 years after surgery. There were no significant differences in the hemodynamic effects with any contemporary prostheses. Mean systolic gradients after aortic valve replacement ranged between 8 and 20 mmHg with calculated orifice areas of 1.5 to 2.2 cm². Following mitral replacement, mean diastolic gradients varied between 3 and 8 mmHg at rest with orifice areas of 1.9 to 2.5 cm². An analysis of comparative thromboembolic rates failed to show a difference of significant magnitude (mitral 3 - 6%/year, aortic 1.5 - 5%/year). There was however a difference in the incidence of thrombotic catastrophic failure. After mitral replacement in patients receiving anti-coagulation, the rate of thrombosis with the caged-ball valve was 0.5 ± .3%/year versus 2.5 ± .7%/year with the Bjork-Shiley valve.

With the non-cloth-covered caged-ball aortic valves, in 182 patients followed for 855 patient-years (mean 4.7 years), there were no cases of thrombotic stenosis. Actuarial data are not available on the tilting disc valves but this complication has been frequently reported. Structural failures have not been seen with the Model 1200/1260 Starr-Edwards aortic prostheses, but have already appeared with glutaraldehyde-preserved porcine xenografts.

These features justify the continued use of the non-cloth-covered ball valve prosthesis as a device whose clinical performance has not been surpassed by any current mechanical valves.

*By invitation

30. Prosthetic Valve Endocarditis: A Comparison of Hetero-graft Tissue Valves and Mechanical Valves

STEPHEN J. ROSSITER *, EDWARD B. STINSON*, PHILIP E. OYER*,

D. CRAIG MILLER *, JAY N. SCHAPIRA, RANDOLPH P. MARTIN*

and NORMAN E. SHUMWAY, Stanford, California

Despite decreasing incidence, prosthetic valve endocarditis (PVE) remains a highly lethal condition, with reported overall mortality rates of 50-60%. Some authors have suggested that gluteraldehyde preserved heterografts (HET) might be more resistant to infection or to certain of its complications than mechanical prosthetic valves.

This study reviewed 2,184 patients who underwent prosthetic valve replacement from 1963 to 1977, with a total follow-up of 7,123 patient-years. Eight-hundred and thirty-seven patients with Hancock HET valves - 384 aortic valves (HET AYR) and 453 mitral valves (HET AVR) were compared with 1,347 patients with mechanical Starr-Edwards valves (SE) - 779 aortic valves (SE AVR) and 568 mitral valves (SE MVR). PVE occurred in 51 patients, 9 early (<2 months post-operatively) and 42 late (>2 months postoperatively). Linearized rates of endocarditis (percent per patient-year) for the various groups were HET AVR 2.2%, HET MVR 0.1% (p<0.01); SE AVR 2.7%, SE MVR 0.4% (p<0.01). Differences between HET and SE groups are not significant but the higher incidence of PVE after AVR, as compared to MVR, is significant. Five of 16 (31%) HET patients and 13 of 35 (37%) of SE patients with PVE died (N.S.). In contrast to some studies, early PVE mortality (5/9 = 55%) was not significantly worse than late PVE mortality (13/42) = 31%). Additionally, comparison of HET and SE group mortality rates failed to reveal statistically significant differences upon analyzing results of medical versus surgical treatment or early versus late endocarditis. There was no significant difference between the two valves in distribution of types of infecting organisms (no Myco-bacterial infections were encountered). The higher incidence of HET valves sustaining early endocarditis (6/16) as compared to SE Valves (3/35) (p<0.05) remains unexplained.

Although heterograft valves have certain advantages compared to mechanical valves, resistance to endocarditis, pathological behavior once sustaining PVE, survival rates with PVE, and curability with medical treatment are similar. Diagnostic aids, including ultrasonic sector scanning, and therapeutic recommendations are discussed.

INTERMISSION - VISIT EXHIBITS

*By invitation

31. The Surgical Anatomy of Kent Bundles Based on Electrophysiologic Mapping and Surgical Exploration

WILL C. SEALY, JOHN J. GALLAGHER*and

EDWARD L. C. PRITCHETT*, Durham, North Carolina

The development of a reliable method for the interruption of Kent Bundles in all locations about the atrioventricular junction of the heart has been hampered by the paucity of anatomic descriptions of the pathways and by their location in areas difficult to expose and unfamiliar to the surgeon. After a review of the 25 reported descriptions, it was evident that they were inadequate to explain many of the findings we had noted in the surface mapping and surgical exploration of 95 patients with Kent Bundles. In this report we will correlate the known anatomic facts with our deductions based on our observations at surgery. This has led to the development of satisfactory operative procedures for the interruption of Kent Bundles in the free wall of both ventricles and in the septal areas as shown by our success in 52 of our last 55 patients. The following conclusions concerning the location of Kent Bundles have been made:

1. Kent Bundles can occur anywhere that there is continuity of the atrium and ventricle.

2. More than one Kent Bundle may be present.

3. Kent Bundles may be found in the pericoronary fat from the sub-epicardial area to the annulus fibrosus.

4. Septal pathways may be adjacent to the AV node-His system, anterior to the atrial septum, or posterior at anyplace beginning at the insertion of the atrial septum into the right fibrous trigone and going to the epicardium over the crux.

5. Access to septal pathways has been facilitated-by entering from the right atrium the triangular space that is beneath the atrial septum and on top of the ventricular septum.

6. The key to the successful interruption of a Kent Bundle is the wide dissection of the fat away from the ventricle and the atrium.

*By invitation

32. Composite Replacement of the Aortic Valve and Ascending Aorta

JOHN E. MAYER, JR. *, W. G. LINDSAY*, Y. WANG*,

C. JORGENSON* and D. M. NICOLOFF, Minneapolis, Minnesota

Cystic medial necrosis primarily affects the ascending aorta resulting in aneurysm formation and secondary aortic insufficiency. Since the entire ascending aorta and sinuses of valsalva are involved, total correction should involve replacement of the aorta from the annulus to the innominate artery takeoff. A composite graft with an incorporated aortic prosthesis and re-implantation of the coronary artery ostia into the graft provides a method for correction. Fifteen (15) patients underwent this procedure between January, 1973 and December, 1976. Seven were Class II, six were Class III and one was operated upon emergently for acute dissection. The procedure consisted of sewing a Lillehei-Kaster aortic prosthesis into one end of a 30 or 35 mm. woven Dacron graft, and then suturing the composite graft to the annulus. The graft extended to just proximal to the innominate in 14 cases, and included the aortic arch in one case. One patient had concomitant mitral valve replacement. The coronary ostia were sewn into the sides of the graft except in one patient who had two saphenous vein coronary bypass grafts. None of the patients required reoperation for excessive postoperative bleeding. There was one early post-operative death (4 days) (6.6%) from redissection of the right coronary artery and one late death (5 months) from left ventricular failure. Ten patients had repeat catheterization 6-12 months after surgery. There were no coronary ostial stenoses, but one pseudoaneurysm developed secondary to suture line separation at left coronary ostia requiring re-operation. One small asymptomatic pseudoaneurysm occurred at the distal suture line and has not required re-operation. There were no aortic paravalvular leaks. The maximal gradient across the valve prosthesis was 10 mmHg in the five patients measured. All surviving patients are Class I or II with follow-up of 7 to 51 months. There has been one questionable episode of embolism which resolved. This technique of composite replacement of the aortic valve and ascending aorta can be accomplished with a low mortality, low incidence of intra- and post-operative bleeding and with satisfactory long-term results in patients with cystic medial necrosis of the aortic root.

*By invitation

33. The Natural History of Saccular Aneurysms of the Left Ventricle

P. GRONDIN, L. CAMPEAU*, O. BICAL*,

P. DONZEAU-GOUGE*, J. G. KRETZ*and R. PETITCLERC*,

Montreal, Quebec, Canada and Paris, France

The natural history of left ventricular aneurysms is poorly known. Most studies are retrospective and based on autopsy cases. Forty consecutive patients having a true saccular aneurysm demonstrated by ventriculography, and who were not, for one reason or another, submitted to surgery, have been followed for a mean period of 6 years and 3 months. Only aneurysms showing an obvious diastolic bulge with a systolic paradoxical motion were retained. These patients were divided in two groups; group one representing patients who, at the time of diagnosis, had little or no symptoms and group two, those having symptoms.

The clinical course differs with the group: the functional status of patients in group one remaining satisfactory. Arrhythmias are encountered in 35% and thrombo-embolic episodes in 17.5% of all patients. Overall survival is satisfactory: 87% at one year and 80% at seven years. Mortality is however elevated (60%) in patients having ventricular extra-systoles at their first examination. Prognosis is influenced clinically, by the presence or absence of symptoms at the time of diagnosis, and anatomically, by the presence of an asynergic area adjacent to the aneurysm and by the extension, on the L.V. angiogram, of both the aneurysm and the asynergic area.

*By invitation

34. Techniques and Results of Ventricular Aneurysmectomy with Emphasis on Antero-Septal Repair

WILLIAM E. WALKER*, WILLIAM S. STONEY,

WILLIAM C. ALFORD, GEORGE R. BURRUS*,

ROBERT A. FRIST*, DAVID M. GLASSFORD*and

CLARENCE S. THOMAS*, Nashville, Tennessee

Over the past 9 years, 175 patients have undergone ventricular aneurysmectomy. Male/female ratio was 4:1, average age was 56 years (range 30 to 74). One hundred forty-six or 83% had concomitant coronary artery bypass (CAP), with an average of 1.8 grafts per patient. Forty-five patients (26%) underwent simple excisions of anterior, apical, or lateral wall aneurysms. One hundred fifteen patients (66%) underwent "antero-septal repair" where the lateral margin of the incised ventricular wall was sutured down to the posterior part of the inter-ventricular septum, to exclude the non-contracting septal myocardium from the circumference of the left ventricle. Fifteen patients (8%) had excision of an inferior wall aneurysm. Fifty patients undergoing antero-septal repair had postoperative ventriculography to assess changes in ejection fraction, akinetic volume, and end-diastolic volume.

There were 15 hospital deaths for an early mortality of 8.5%. Advanced age was not a factor in early mortality (3 of 32 patients between 65 and 74 years old died) nor did age affect long-term survival. Overall, adjuvant CAB did not affect early mortality nor long-term survival, but none of 20 patients undergoing aneurysmectomy without CAB in the past 6 years died. Three patients were moribund when operated upon, 1 survived. Six patients required intra-aortic balloon support for an average of 4 days, with 4 survivors. Actuarial survivals (b stand, devn.) were 80±4% and 62±5% for the whole group at 2 and 5 years respectively. Despite being slightly older, the women fared better with 70±6% vs. 58±5% survival at 5 years (p less than 0.01). Heart failure following recent myocardial infarction did not preclude a good result, in fact these patients did very well. Three patients also had closure of a VSD, and all survived. Actuarial 5-year survival following antero-septal repair was 65±5%. There was a distinct group of patients with very large aneurysms but with good contraction of the rest of the ventricle who had an excellent result. Postoperative ventriculography confirmed the return towards more normal hemodynamics following antero-septal repair.

Good results attend an aggressive approach to ventricular aneurysmectomy. Suitable vessels should be bypassed. Satisfactory results can be attained with the "bad" ventricle. Antero-septal repair is the optimal approach to the "typical" aneurysm.

*By invitation