American Association for

Thoracic Surgery

56th Annual Meeting

Scientific Program

FRIDAY MORNING, APRIL 23, 1976

8:30 A.M. Business Session (Limited to Members)

Los Angeles Ballroom

8:45 A.M. Scientific Session

Los Angeles Ballroom

1. Pulmonary Artery Conduits in Infants Under Six Months of Age

PAUL E. EBERT, SAUL J. ROBINSON*, PAUL STANGER*

and MARY ALLEN ENGLE*, San Francisco, California and

New York, New York

Nine infants with complex congenital anomalies, four with either Type I or II truncus arteriosus, and five with various forms of pulmonary atresia have undergone corrective surgery to separate the systemic and pulmonary circulations with reconstruction of right ventricular-pulmonary artery continuity, using either a human aortic allograft or a dacron conduit with a Porcine valve. The infants weighed between 2.3 and 4.3 kilograms and were between 2 and 17 weeks of age. In all nine the ventricular septal defect was closed and an atrial septal defect repaired in two. Eight of the nine have survived the operative procedure.

Postoperative catheterization in six have shown conduit pressures as high as two-thirds systemic with some restriction at the site of distal anastomosis. Cardiac output has been normal and pulmonary vascular resistance has not been elevated. One operative fatality was due to irreversible pulmonary hypertension. Profound hypothermia with or without total circulatory arrest was used in all nine infants. The differences in technique of hypothermia employed as well as the technical aspects of attachment of the graft to the delicate small right ventricular chamber will be discussed. Low mortality and optimistic postoperative hemodynamic measurements lend encouragement to early separation of the circulation as a better means of palliation in infants with truncus arteriosus to reduce the likelihood of pulmonary vascular disease.

*By invitation

2. Microporous Expanded Polytetrafluoroethylene Arterial Prosthesis for Construction of Aorta-Pulmonary Shunts in Cyanotic Infants

ALAN B. GAZZANIGA, Irvine California

JOHN J. LAMBERTI*, Chicago, Illinois

RALPH D. SIEWERS*, Pittsburgh, Pennsylvania

DONALD R. SPERLING* and WILLIAM R. DIETRICK*, Irvine, California

RENE A. ARCILLA* and ROBERT L. REPLOGLE, Chicago, Illinois

Despite improved results with early correction of congenital heart anomalies in cyanotic infants, certain lesions are not amenable to immediate repair.Systemic to pulmonary artery shunts are necessary for survival in some cases. The traditional shunt operations have involved direct anastomosis of the aorta or sub-clavian artery to the right or left pulmonary artery; and while these operations are life saving, significant immediate and long-term complications can occur.

A microporous expanded polytetrafluoroethylene PTFE 4.0 mm arterial prosthesis was used to construct aorta-pulmonary shunts in 10 infants, ages 1 to 180 days (28 days) weighing from 2.0 to 5.0 kg (3.1 kg). Nine patients had pulmonary artresia, one had tricuspid artresia, all had associated intracardiac defects and were severely cyanotic with arterial oxygen saturations below 70%. Nine of the 10 patients underwent emergency surgery. The graft was anastomosed from aorta to the main pulmonary artery in 8 infants, to the right pulmonary artery in one, and to the left pulmonary artery in one. Nine of 10 patients survived the operation. The shunt was patent at necropsy in one patient who died a week post-operatively secondary to an intracranial hemorrhage. The 8 remaining patients are alive and well 2-6 months (3.3 mos.) postoperatively. All infants have functioning shunt murmur, are gaining weight, and are acyanotic at rest.

The desirable features of aorta to main pulmonary artery shunts using the PTFE prosthesis are rapid performance, minimal lung retraction at surgery, bidirectional and uniform flow to the pulmonary arteries, potential ease of subsequent closure, expected equal growth of both pulmonary arteries, accurate size of the anastomosis, and autogenous vessels are not sacrificed (Blalock). Results thus far indicate that use of the PTFE prosthesis in infants is practical and safe.

*By invitation

3. Optimal Age for Primary Repair of Ventricular Septal Defect

EUGENE H. BLACKSTONE*, JOHN W. KIRKLIN, ALBERT D. PACIFICO*,

AZAI APPELBAUM*, and LIONEL M. BARGERON*, Birmingham, Alabama

Our experience with 1) primary repair for ventricular septal defect (VSD) from 1967 to April 1975 (190 patients (pts)) has been studied in combination with 2) late results of an earlier experience reported in the literature (75 pts), by a method of joint probability analysis, to determine currently the optimal age and techniques for primary closure of VSD under a variety of anatomical and hemodynamic circumstances, and to identify problem areas where future improvements are needed.

1) 165 pts (86.8% of the 190) had a single VSD. Hospital mortality was 4.8%. At age <6 months (mos), it was 27.3%; 6-12 mos, 20%; 12-24 mos, 5.3%; over 24 mos. 0.8%; with mean pulmonary pressure (PAP) less than 25 mmHg, it was 1%; between 25 and 50, 6.8%. Significant residual L-→-R shunting occurred in 3 pts, with incidence not related to age at repair. One patient (age 16 years) developed heart block. Surgical techniques varied, and their effects have been analyzed.

2) Re-analysis of the published data indicates that pts with severe pulmonary hypertension age 2 years (yrs) or less at repair had 3% probability of PAP>35 mmHg 5 yrs or more after repair; age 2-5 yrs at repair, 38%; >5 yrs, 52%. All pts with PAP <35 mmHg at time of repair had 2% probability of PAP>35 mmHg 5 yrs later; with PAP 35-50 mmHg, 17%; >50 mmHg, 41%.

The joint probability analysis of 1) and 2) indicates that the probability of surviving operation and having PAP < 35 mmHg 5 yrs later is in general greatest when operation is performed at age 17.5 mos; however, the higher PAP preoperatively, the lower the age for minimizing this risk (at PAP of 35 mmHg, 20 mos; at 50 mmHg, 15 mos; at 70 mmHg, 12 mos). Similar analyses involving additional factors, including multiplicity of VSD, have identified optimal age and techniques for repair in a variety of individual types of pts with VSD, and problem areas requiring further study.

*By invitation

4. Anatomic Correction of Transposition of the Great Arteries

ADIB D. JATENE*, V. F. FONTES*, P. P. PAULISTA*,

L. C. B. de SOUZA*, F. NEGER*, M. GALANTIER* and

J.E.M.R. SOUZA*, Sao Paulo, Brazil

Sponsored by E. J. Zerbini, Sao Paulo, Brazil

The authors present a new approach for anatomical correction of transposition of the great arteries. The two coronary arteries with a piece of aortic wall are transposed to the posterior artery. The two aortic openings are closed with a patch. The aorta and pulmonary artery are transected, contraposed and then anastomosed. The interventricular septal defect is closed with a patch through a right ventriculotomy because the right ventricle is no longer systemic.

Two patients aged 3 months and 40 days weighing 4,200 and 3,700 g respectively were operated on with deep hypothermia and total circulatory arrest. There was good recovery from the operation with normal cardiocirculatory conditions. The first patient developed renal failure and died on the third postoperative day. During this time the cardiocirculatory conditions were good. The second patient made an uneventful recovery. The hemodynamic study 20 days after surgery showed the complete correction of the malformation. Five and a half months after operation, he weighs 7,500 g and the evolution is very good.

The authors believe that this operation will be reproducible by most of cardiovascular surgeons and will be an alternative to the Mustard procedure, specially to those patients with interventricular septal defect and pulmonary hypertension.

INTERMISSION - VISIT EXHIBITS

*By invitation

5. Intra-operative Atrial Activation Mapping Before, During and After Mustard Operation

MARC R. deLEVAL*†, JOHN H. WITTIG* and

JAROSLAV STARK*, London, England

Sponsored by Aldo Casteneda, Boston, Massachusetts

Thirty-two patients with transposition of the great arteries underwent 35 point bipolar epicardial and endocardia! mapping during four stages of the Mustard operation in an endeavour to determine the electrophysiological basis of the postoperative supraventricular arrhythmias associated with this operation. Comparisons were made between atrial activation patterns and times before and after each of the following stages: 1. cannulation of superior vena cava (SVC), 2. atriotomy, 3. excision of the atrial septum, 4. placement of interatrial baffle. SVC was can-nulated directly 1-2 cm above the right atrial (RA) - SVC junction or through the body of RA appendage. The interatrial septum was excised in all patients. The coronary sinus was cut back in 11 patients and left intact with suture line behind it in 16 patients, pericardial baffles were then inserted. During stage 1. eleven patients underwent epicardial mapping. No significant difference in atrial activation was noted with either technique of cannulation. The effect of atriotomy was evaluated with epicardial and endocardial mapping in all thirty-two patients. Atriotomy did not lengthen atrial activation times (66.1 il6 msec) but significantly altered atrial activation over the posterior septum in 25 patients. In seven patients, the earliest area of atrial depolarisation shifted from its superior vena caval position to the crista supraventricularis prior to atriotomy or cannulation. Atriotomy in these patients lengthened atrial activation 25.1 ± 6.3 msec. In one of these seven patients atriotomy transected the area of earliest depolarisation on the crista. Post-operatively this patient developed bouts of paroxysmal atrial tachycardia. Stage 3 did not produce significant changes in atrial activation times or directions. During stage 4, eleven patients were evaluated with coronary sinus cutbacks and baffle placement and 16 patients with just baffle placement. Atrial activation times were unchanged in all patients with coronary sinus cutback, but the direction of atrial activation was across the anterior septa) region due to conduction delays over the middle and posterior septum. One patient manifested 1st degree heart block in CS cutback group when slowed conduction was mapped in the anterior septal area.

†Dr. deLeval was the 24th Evarts A. Graham Memorial Traveling Fellow (1973-1974).

*By invitation

6. Nonoperative Closure of Left-to-Right Shunts

NOEL L. MILLS and TERRY D. KING*, New Orleans, Louisiana

Efforts to close left-to-right shunts at Ochsner Foundation Medical Center have been directed toward ASD and PDA.

PDA's were constructed in dogs by interposing a segment of jugular vein between the aorta and main pulmonary artery. Five dogs which had PDA's closed by a plug device through the femoral vessels were sacrificed at 6 to 12 months. Histologic section showed good fibrous ingrowth into the polyurethane foam with endothelial covering on aorta and pulmonary artery ends. There were no migrations and no residual shunts.

Twelve patients had ASD's sized and located as to position at the time of cardiac catheterization. Sizes ranged from 13 mm. to > 40 mm. Five patients had centrally positioned secundum ASD's closed with double umbrella devices, 25 to 35 mm. in diameter. Seven patients were found at catheterization to have contraindications for umbrella closure (anomalous pulmonary venous return, 2; large inferior or superior secundum ASD, 2; common atrium, 1; sinus venosus ASD, 1; associated VSD, 1). ASD size and location of those who underwent operative closure were compared to measurements at catheterization, and variation was insignificant.

Follow-up studies from two to six months on five patients with umbrella closure has revealed no hemolysis, arrhythmias, thromboembolism, migration or other untoward effects.

11:15 A.M. Presidential Address

"THE CHALLENGE OF PROGRESS"

David J. Dugan

*By invitation