American Association for

Thoracic Surgery

74th ANNUAL MEETING

New York Hilton Hotel, New York, NY

APRIL 24-27, 1994

MONDAY MORNING, April 25, 1994

8:30 a.m. BUSINESS SESSION (Limited to Members)

8:45 a.m. SCIENTIFIC SESSION - Grand Ballroom

Moderators: Aldo R. Castaneda, M.D.

James L. Cox, M.D.

1. POSTINTUBATION TRACHEAL STENOSIS: LATE RESULTS OF SURGICAL TREATMENT

Hermes C. Grille, M.D., Dean M. Donahue, M.D.*, Douglas J. Mathisen, M.D., Cameron D. Wright, M.D.* and John C. Wain, M.D.*

Boston, Massachusetts

493 patients underwent 505 tracheal resections and reconstructions for postintubation stenosis from 1965 to 1992. 52 had had prior attempts at surgical resection, 52 others had undergone various forms of tracheal or laryngeal repair, and 40 laser treatment. There were 248 cuff lesions, 174 stomal lesions, 36 at both levels, and 35 of indeterminate origin. 60 with major laryngeal injuries required complete resection of anterior cricoid cartilage and anastomosis of trachea to thyroid cartilage, and 111 had partial anterior cricoid resection. Cervical approach was used in 343, cervicomediastinal in 144, and transthoracic in 6. Length of resection was 1.0 cm - 7.5 cm. 44 had laryngeal release to reduce anastomotic tension.

449 patients (91%) showed good (86%) or satisfactory (5%) results. 12 of 17 who failed underwent repeat reconstruction. 12 required postoperative tracheostomy or T-tube for extensive or multilevel disease. 15 died (3%). The most common complication, suture line granulations (9.5%), has almost vanished with use of absorbable sutures. Wound infection occurred in 15 (3%), and glottic dysfunction in 11 (2.2%). 3 had postoperative innominate artery hemorrhage. Resection and reconstruction offers optimal treatment for postintubation tracheal stenosis.

*By invitation

2. EFFECTS OF HYPOTHERMIC CIRCULATORY ARREST ON NEUROLOGIC AND DEVELOPMENTAL OUTCOME AT AGE ONE YEAR

Richard A. Jonas, M.D., Gil Wernovsky, M.D.*, David C. Bellinger, Ph.D.*, Leonard A. Rappaport, M.D.*, Karl C. Kuban, M.D.*, Patrick Barnes, M.D.*, Roy Strand, M.D.*, David Wypij, Ph.D.* and Jane W. Newburger, M.D.*

Boston, Massachusetts

We compared neurologic and developmental status at age 1 yr in patients with D-TGA who had been enrolled before their arterial switch operation in a prospective, randomized trial comparing deep hypothermia with predominantly circulatory arrest (CA) vs. predominantly low-flow cardiopulmonary bypass (LF). Neurologic exam, developmental testing, and magnetic resonance (MR) interpretations were performed by blinded investigators. One-year assessments were available in 155 patients (91% of those enrolled).

Abnormalities on neurologic examination tended to be more common among infants randomized to the CA strategy (p=.057). Similarly, neurologic abnormalities were significantly associated with longer duration of CA (p = .018). Specific abnormalities noted in the combined treatment groups were cerebral palsy (CP) in 6 children (4%); hypotonia (not with CP) in 28 (18%); hypertonia (not with CP) in 11 (7%); focal abnormalities (not with CP) in 5 (3%); and abnormalities of special senses in 2 (1%).

Scores on the Psychomotor Development Index (PDI) (motor function) of the Bayley Scales were lower among infants randomized to CA (p = .003). Similarly, longer duration of CA was associated with lower PDI score (p = .01). Scores on the Mental Development Index (precursors of cognitive function) tended to be lower in the CA group (p = .06). However, the duration of CA was not significantly associated with MDI score. The score on the Pagan Test of Infant Intelligence was not related to support method.

Abnormalities on MR were not associated with treatment assignment or with duration of CA. In the combined treatment groups, 11 (8%) had possible abnormalities and 22 (15%) had definite abnormalities. The most common specific abnormalities included ventricular dilation (20. 14%) and infarction (13, 9%).

In multivariate analyses, EEC seizure activity in the first 48 hours postoperatively was associated with lower PDI scores (p = .001) and greater risk of MR abnormalities (p<.001).

In summary, longer duration of CA is associated with a greater likelihood of abnormal neurologic examination and worse motor function at age one year, although early cognitive function was not affected. Furthermore, postoperative EEG seizure activity is an independent predictor of poor motor function and structural brain abnormalities on MR. The significance of these findings for longer-term neurologic outcome awaits follow-up of the study cohort at age 4 years.

*By invitation

3. MICROEMBOLI DURING CABG. GENESIS AND EFFECT ON OUTCOME

Richard E. Clark, M.D., Donalee A. Davis, C.N.R.N.*, Mark R. Lovell, Ph.D.*, George J. Magovern, M.D. and Jon Brillman, M.D.*

Pittsburgh, Pennsylvania

The hypothesis tested in this prospective clinical study was that microemboli (ME) generation were both a function of cardiopulmonary bypass and the operation and that outcomes were related to total number of microemboli. One hundred eleven patients having CABG had continuous transcranial Doppler (TCD) recordings of middle cerebral artery flow made from the time of induction to transfer to the ICU using a 2 Mz transducer. ME were recorded as clear unambiguous instantaneous perturbations of the velocity signa. Correlations of ME to surgical intervals were made: pre-cannulation, aortotomy, insertion and removal of the aortic cannula, vent, and cardioplegia needle, aortic cross-clamping (total and partial) and clamp removal, defibrillation, displacement of the heart and other maneuvers. Pre- and post-cognitive neuropsychologic (NP) testing was performed in 25 patients for orientation, attention, comprehension, repetitive, naming constructional ability, memory, calculation, and reasoning similarities and judgement. The total ME during CPBP were correlated with post-operative encephalopathy, CVA and cardiopulmonary complications. Analysis of variance for repeated measures, chi square (Pearson, Mental-Hacngel, and Fisher's) and correlations by Pearson's and Spearman's methods were made.

There was a mean of 32±3 ME per patient detected. CPBP contributed approximately 10-20% of the total ME/pt. Aortic cannulation, aortic clamp removal (total and partial) and especially cardiac displacement contributed most of the ME. All phases of the NP test were slightly depressed (<0.03) in the immediate post-operative interval. The most striking were language comprehension (p<0.003), language repetition p<0.002), constructional ability (p<0.016), and reasoning judgement (O.01). Total ME were only related to decreases in language repetition (p<0.02).

ME total counts >65 were related to post-operative encephalopathy, CVA, and cardiopulmonary complications (p≤0.02) as 10 of 13 patients had one of these complications. These data show that the initial hypothesis that CPBP was a major contributor of ME was incorrect. ME were markedly reduced during aortic cannulation by use of a dry air-filled cannula as opposed to a fluid-filled one. A greater number of cases are now performed under a single cross-clamping and repeated lifting of the heart to inspect posterior anastomoses is avoided whenever possible. Further, high numbers of ME (2 x mean) or >65 increase risk of encephalopathy CVA and cardiopulmonary complications by at least 20% above that expected. It is concluded that non-invasive TCD studies of a middle cerebral artery velocity have been useful in determining etiology and possible remedial measures for reduction in CNS complications after operations.

9:45 a.m. INTERMISSION - VISIT EXHIBITS

*By invitation

10:30 a.m. SCIENTIFIC SESSION - Grand Ballroom

Moderators: Robert B. Wallace, M.D.

James L. Cox, M.D.

4. CARDIAC TRANSPLANT VASCULOPATHY: A MULTI-VARIABLE ANALYSIS OF DISEASE DEVELOPMENT AND MORBID EVENTS

David C. McGiffin*, Timo Savunen, M.D.*, James K. Kirklin, M.D., David C. Naftel, Ph.D.*, Robert C. Bourge, M.D.*, Connie White-Williams, R.N.* and Tero Sisto, M.D.*

Birmingham, Alabama

Coronary artery disease (CAD) after cardiac transplantation (C Tx) is possibly the major obstacle to long-term survival, yet limited information is available about the determinants and patterns of disease progression and risk factors for serious coronary events. The development and progression of CAD after C Tx was analyzed in 217 consecutive patients (pts) undergoing C Tx between 1981 and December 1990 with followup through 6/30/92. Post C Tx coronary angiograms (angios) (n=632 in 157 pts) were reviewed and scored according to location and extent of CAD. The actuarial freedom from any CAD (by angio) was 81% at 2 yrs., 47% at 5 yrs, and 20% at 8 yrs post C Tx. Males developed CAD more often than females (30% vs 50% free of CAD at 5 yrs., p=.01). By multivariable analysis, risk factors identified for CAD included recipient pre-Tx positive CMV serology (p=.002) and older donor age (p=.07). Progression of CAD was compared among pts with early vs. later onset of CAD (by angio); there was no difference in average CAD progression among pts who developed disease in first 2 yrs vs those with CAD-free (angio) interval of 3-6 yrs (p=.4). Serious coronary events (CE) [CAD severe enough for retransplantation (re-Tx) (n=8) and/or death from CAD (n=9)] occurred in 15 pts, of which 4 underwent re-Tx. The actuarial freedom from CE was 88% at 5 yrs and 79% at 8 yrs. By multivariable analysis, only race mismatch (p=.03) and male recipient (p=.07) were risk factors for CE. The rate of CAD progression was greater in the group who suffered CE vs those who did not (p<.0001), but 6 of the 15 pts (40%) with CE died suddenly with severe CAD without angio evidence of CAD a mean of 13 months before death.

Inferences:

* CAD by angio exists in >80% of late C Tx survivors by 8 years, and the incidence is greater among recipients with positive CMV serology and older donor hearts.

* Once identified, the rate of angiographic CAD progression is similar regardless of the prior disease-free interval.

* Despite the frequency of CAD, serious coronary events (relisting for re-Tx or CAD death) occur in only about 20% of pts by 8 yrs, and are more likely among male recipients and with donor/recipient race mismatch.

* Despite routine yearly surveillance angios, about 40% of coronary events present as sudden death without evident CAD.

*By invitation

5. PULMONARY BIPARTITION WITH BILATERAL LOBAR TRANSPLANTATION: A NEW APPROACH TO ORGAN SHORTAGE

Jean-Paul J. Couetil, M.D.*, Antoine Achkar, M.D.*, Christian R. Brizard, M.D.*, Peter L. Birnbaum, M.D.*, Alain Guinvarch, M.D.*, Jean-Philippe Kieffer, M.D.*, Didier F. Loulmet, M.D.*, Catherine I. Amrein, M.D.*, Remain J. Guillemain, M.D.*, Patrick Chevalier, M.D.*, John Y.M. Relland, M.D.*, Jacques Rochemaure, M.D.* and Alain F. Carpentier, M.D., Ph.D.

Paris, France

The scarcity of small donors has significantly limited lung transplantation (LTx) for pediatric and small adult patients. Lobectomy of grafts procured from size unmatched donors overcame this difficulty but only in a few selected cases; in addition, it represented a waste of lung tissue. In our research laboratory, we have shown that it is possible to divide one lung with careful partition of the vascular and bronchial structures in order to obtain two viable lobar grafts suitable for a bilateral LTx in a smaller animal. In this paper, we report our clinical experience of a bilateral Tx using the donor left lung in 3 patients with an average weight of 44 kg. The indications were idiopathic pulmonary fibrosis, cystic fibrosis (CF) and emphysema. The CF patient received in addition to the BLTx a reduced-size liver transplant for associated end-stage liver failure. Recipients (R) and donors (D) characteristics are given in the following table.

The surgical technique consists of a careful partitioning of the left donor lung, a bilateral anterior thoracotomy of the recipient, and, under cardio-pulmonary bypass, the implantation of the lower lobe in the left hemithorax and the upper lobe in the right hemithorax. Vascular and bronchial connections are facilitated by leaving a long pedicle on the recipient side. The pulmonary artery anastomosis for the donor left upper lobe is performed with the "fissure side" of the artery to ensure an anastomosis without torsion. An end to end bronchial anastomosis overcomes the problem of size discrepancy.

All 3 patients are alive and well 1 to 6 months after the operation. All were discharged from the hospital within the first or second postoperative month. No technical problems were identified. Repeated bronchoscopy has demonstrated satisfactory healing without early stricture formation. All patients demonstrated normal room air arterial blood gases postoperatively. Forced expiratory volume I/sec has shown progressive improvement with all patients achieving 75% of predicted values. A perfect adaptation of the transplanted lobes to the recipient pleural space was demonstrated by postoperative CT scan.

In conclusion, bilateral lobar transplantation is possible in hypotrophic adults or children with large size discrepancy from the donor lung. It may help resolve the problem of donor availability in the pediatric population. Further experience and follow-up are needed to define the indications and the possible limitations of this procedure.

11:15 a.m. PRESIDENTIAL ADDRESS

The Education of a Cardiothoracic Surgeon:

An Appollonian Quest

Aldo R.Castaneda, M.D., Boston, Massachusetts

12:00 p.m. ADJOURN FOR LUNCH IN EXHIBIT HALL - VISIT EXHIBITS

*By invitation