The American Association

For Thoracic Surgery

77TH ANNUAL MEETING

May 4-7, 1997

Sheraton Washington Hotel

Washington, DC

MONDAY, MAY 5, 1997

8:00 a.m. BUSINESS SESSION (Limited to Members) Sheraton Ballroom

8:15 a.m. PLENARY SCIENTIFIC SESSION

Sheraton Ballroom

Moderators: David B. Skinner, M.D.

James L. Cox, M.D.

1. OUTFLOW OBSTRUCTION AFTER THE ARTERIAL SWITCH OPERATION: A MULTI-INSTITUTIONAL STUDY.

William G. Williams, M.D., Jan M. Quaegebeur, M.D., John W. Kirklin, M.D. and Eugene H. Blackstone, M.D.

Toronto, Ontario, Canada; New York, New York and Birmingham, Alabama

Discussant: Frank L. Hanley, M.D.

Whether or not right-sided and left-sided outflow obstruction immutably accompanies the arterial switch operation to some degree is unknown, as are factors that may decrease its prevalence. This was studied in 514 neonates undergoing an arterial switch operation for simple transposition or transposition with ventricular septal defect entering 23 institutions before 15 days of age between January 1, 1985 and March 1, 1989. Each patient has been followed yearly.

The time-related freedom from percutaneous or surgical intervention for obstruction across time is shown in the first figure. The results of a multi-variable analysis of right-sided events is shown in the table. The influence of the coronary pattern and the improvement with date of operation are shown in the second figure. The "base prevalence" predicted at the end of the experience in the best subset of patients is contrasted with those receiving coronary excision away from the transection site in the third figure.

Inferences (derived assumptions): 1) There is a "base valence" (5%-10%) of the need for reintervention for right-sided obstruction, which is predominately late postoperatively. 2) When the enlargement of the base of the pulmonary trunk (PT) effected by the operation is less (for example, when the coronary explant is away from the transection site or when the left coronary artery comes from sinus 2), the prevalence is increased. 3) Apparently mild and often overlooked congenital variability of the right ventricular outflow tract and "outflow valve" may occasionally yield a morphology which increases the prevalence (albeit more proximal). 4) Apparently mild and often overlooked variability in the "LeCompte maneuver" (performed in all but 20 patients in this study, with 2 right-sided events) may increase the prevalence (variability less when the LeCompte is not done), albeit more distal in the pulmonary artery. 5) Inexperience and operator variability may result in a "less than optimal" PT reconstruction which increases this prevalence (therefore, a date of operation and institution variables in the analysis). 6) These same types of variability probably affect the aortic root, but its native characteristics plus higher distending pressure make the basic prevalence considerably less than that for the "right side".

Incremental Risk Factors for Intervention Right-Sided Obstruction	Hazard phase
	Early	Late
Left coronary artery arising from sinus 2	P = .002
Coronary explant away from transection site		P =.01
Institution X	P = .0003
Institution Y	P = .0002
Institution Z		P = .01
Earlier date of arterial switch	P = .01

*By invitation

§2. VALVE REPAIR VERSUS REPLACEMENT FOR MITRAL INSUFFICIENCY: WHEN IS A MECHANICAL VALVE STILL INDICATED?

Eugene A. Grossi, M.D.*, Aubrey C. Galloway, M.D., Greg H. Ribakove, M.D.*, Alfred T. Culliford, M.D., Rick Esposito, M.D.*, Julie Delianides, M.A.*, Patricia Buttenheim, M.A.*, F. Gregory Baumann, Ph.D.*, Frank C. Spencer, M.D. and Stephen B. Colvin, M.D.*

New York, New York

Discussant: Gary W. Akins, M.D.

While many advantages of mitral valve reconstruction are well known, the specific subgroup of patients in which mechanical valve replacement offers superior long term results remains uncertain. This study addressed this issue by examining the long term results of mitral valve surgery in patients (pts) with mitral insufficiency who received either a St. Jude valve (SJV) (n = 516) or a mitral reconstruction with ring annuloplasty (MVR) (n = 725) between 1980 and 1995. Overall operative mortality was 7.2% in the SJV pts and 5.4% in the MVR pts (NS); isolated mortality was 2.5% in the SJV pts and 2.2% in the MVR pts (NS). Three hundred and forty pts had a follow-up interval > 5 yrs; 51 pts had a follow-up interval > 10 yrs (mean follow-up = 39.8 months; 98.5% complete). Actuarial analysis of freedom from late cardiac death (LCD), reoperation (REOP), and all valve-related complications (AVC) is shown below:

Freedom from:	5 Years (%)		8 Years (%)		p
	SJV	MVR	SJV	MVR
All Patients
LCD	87.8	90.1	86.8	84.1	NS
LCD & REOP	84.2	82.9	81.5	73.1	NS
LCD, REOP, & AVC	84.0	74.4	79.9	64.8	NS
Isolated NonRheumatic MVR
LCD	91.7	98.1	91.7	95.4	<.05
LCD & REOP	85.4	93.6	85.4	88.3	.08
LCD, REOP, & AVC	85.0	87.5	82.2	82.1	NS
Isolated Rheumatic MVR
LCD	91.7	98.1	91.7	98.1	.13
LCD & REOP	85.4	84.0	85.4	84.0	NS
LCD, REOP, & AVC	85.0	71.5	82.2	71.5	.04
Concomitant Valve
LCD	89.1	80.0	89.1	60.5	NS
LCD & REOP	88.2	72.2	88.2	51.0	<.01
LCD, REOP, & AVC	88.0	67.2	83.7	50.8	<.001

Cox multivariate analysis in isolated, non-rheumatic mitral valve pts revealed that MVR was independently associated with increased survival from late cardiac death (p = .04) irrespective of preoperative NYHA class. In rheumatic and multiple valve pts SJV offered better freedom from late cardiac death, reoperation and all valve-related complications. MVR is preferred for isolated, non-rheumatic pts, whereas SJV gives improved late results in rheumatic and multiple valve pts.

§Authors have a relationship with Baxter, St. Jude Medical and Medtronics

*By invitation

3. REOPERATIVE TRACHEAL RESECTION AND RECONSTRUCTION FOR FAILED REPAIR OF POSTINTUBATION STENOSIS.

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

Boston, Massachusetts

Discussant: F. Griffith Pearson, M.D.

Primary tracheal resection and reconstruction for postintubation stenosis restores airway continuity and avoids life-long tracheostomy. Success can be expected in over 90% (408/450) of cases with a low incidence of morbidity (15.1%, 68/450) and mortality (2.2%, 10/450). When primary resection fails, there is still an opportunity for restoration of the airway, but the operation is of much greater complexity with the potential for added morbidity and mortality. Timing of surgery, airway management, and attention to technical detail are critical to successful reoperation.

We have had experience with 69 patients undergoing reoperation for tracheal stenosis following failed primary repair. Temporary airway management was accomplished with T-tubes in 18 and tracheostomy in 14. The amount of trachea removed at the initial operation was 3.5 cm (range 1.0 to 5.5). The average amount of trachea resected at the reoperation was 3.4 cm (range 1.0 to 6.0). A release maneuver (laryngeal = 17, hilar = 1) was employed in 18 patients (26.1%), compared to 7.1% (32/450) in our series of intial repairs. There were 14 major complications (20%) and 15 minor complications (22%). The major complications were restenosis (N = 3), anastomotic granulations (N = 3), sternal infection (N = 3), dehiscence (N = 2), pneumonia (N = 2), and temporary vocal cord paralysis (N=1). There were four failures (5.8%) requiring permanent T-tube or tracheostomy. Two patients required a second reoperation for restenosis (2.8%), both with good long term results. There were two deaths in the series (2.8%). Successful reconstruction of the airway was achieved in 88.4% (good = 51, satisfactory = 10) at a mean follow-up of over 3 years. Reconstruction following failed repair for tracheal stenosis is possible by adhering to certain principles and attention to the technical details of the operation.

*By invitation

4. SUSTAINED RELIEF TO THE LEFT VENTRICLE IN

HYPERTROPHIC OBSTRUCTIVE CARDIOMYOPATHY BY EXTENDED MYECTOMY AND RECONSTRUCTION OF THE SUBVALVULAR MITRAL APPARATUS.

Friedrich A. Schoendube, M.D., M.S.*, Heinrich G. Klues, M.D.*, Sebastian Reith, M.D.*, Andreas Franke, M.D.*, Frank A. Flachskampf, M.D.*, Peter Hanrath, M.D.* and Bruno J. Messmer, M.D.

Aachen, Germany

Discussant: Robert B. Wallace, M.D.

Background: Classical myotomy-myectomy for patients with severely symptomatic hypertrophic obstructive cardiomyopathy (HOCM) represents inherent risks of ventricular septal defect or incomplete relief. A modified surgical technique with extended myectomy and reconstruction of the subvalvular apparatus was developed to allow safe and lasting relief of the left ventricular outflow tract obstruction.

Material and Methods: Between 1979 and 1996, 74 patients (45 male), age 49 (15-73) years were operated upon HOCM. All patients were severely symptomatic despite adequate medication. Pre-operative echocardiographic studies showed moderate mitral regurgitation in 27% and severe mitral regurgitation in 5% of the patients. All patients had a significant SAM (3-4+). Concommittant surgical procedures were performed in 17 patients: CABG 11/74 (15%), MV-Repair: 2/74 (3%), ICD: 1/74 (1.5%), Ao. asc. aneurysm: 1/74 (1.5%), RV-myectomy: 2/74 (3%).

Results: Perioperative mortality (30 days) was 0%, hospital mortality concerned one patient with septic multi-organ failure (1.3%). Peri-operative non-fatal complications included one transient cerebral attack with full recovery, three patients required permanent pacemaker therapy. No ventricular septal defect occurred in the whole series. Long-term follow-up (73/74 patients / 98%) comprised a total of 434 patient-years (py) (mean 84, 1-204 months). Linear mortality was 1.4%/py (7/73), ten year survival was 86 ± 7% (5-year 94%). No sudden cardiac death occurred during follow-up. Echoes were performed for 65/66 patients at latest follow-up (1996). Normal LVEDD (46 ± 6 mm) and LVESD (32 ± 8 mm) were shown, septal thickness was particularly small (13.4 ± 4 mm) for HOCM patients (pre-op: 25 ± 5 mm, p < 0.05). None of the patients showed at follow-up relevant systolic anterior movement of the mitral valve (SAM) and no significant mitral regurgitation was observed. Eleven patients had pre- and post-operative 3-D reconstruction from multiplane transesophageal echoes and showed an increase of the minimal cross-sectional area of the LVOT from 1.1 ± 1.0 Cm² pre-operatively to 4.4 ± 2.7cm² postoperatively (p < 0.05). Maximal deviation of the mitral leaflets fell from 15 + 7 mm pre- to 7 ± 8 mm postoperatively (p < 0.05) as consequence of subvalvular reconstruction. Functional capacity of the patients at long-term follow-up is still excellent for the majority of patients (65%) in NYHA class I or II. Patients being in class III (NYHA) are all in their 8th decade of life and nobody was in class IV.

Conclusion: Transaortic extended myectomy and reconstruction of the subvalvular mitral apparatus has proven to be a highly effective therapy for patients with severely symptomatic hypertrophic obstructive cardiomyopathy because: 1) obstruction to left ventricular outflow tract is reliably eliminated, 2) long-term results show an excellent functional and hemodynamic status of the patients, 3) annual mortality rate is low and no sudden cardiac death occurred during follow-up.

9:40 a.m. EVARTS A. GRAHAM MEMORIAL TRAVELING FELLOW PRESENTATION

Monica Robotin-Johnson, M.D., Sydney, Australia

9:45 a.m. INTERMISSION - VISIT EXHIBITS

*By invitation

10:30 a.m. PLENARY SCIENTIFIC SESSION

Sheraton Ballroom

Moderators: Floyd D. Loop, M.D.

James L. Cox, M.D.

5. LATE RESULTS OF 151 AORTIC VALVE PRESERVING OPERATIONS IN PATIENTS WITH ANEURYSMS OF THE ASCENDING AORTA AND ROOT.

Petra J. Gehle, M.D.*. Rosemary C. Radley-Smith, F.R.C.P., M.B.B.S.* and Magdi H. Yacoub, F.R.C.S., Ph.D.

London, England

Discussant: Tirone E. David, M.D.

A technique of excising aneurysms of the ascending aorta and root with resuspension of the aortic valve and implantation of the coronary ostia into a dacron graft was devised in 1979 and used by one surgeon whenever possible thereafter. The aortic sinuses are excised to within one millimeter of the aortic anulus. A dacron tube of the appropriate size is fashioned to have three tongue-shaped processes to match the three reconstituted sinuses. To date 151 patients (70% of all patients undergoing resection of aneurysm of the ascending aorta) were operated on using this technique. Their ages ranged from 2 to 77 years (mean 43); 46 patients were female, 105 male; 64 patients had skeletal manifestations of Marfan syndrome. Nearly one third (49 patients) presented with acute or chronic type A dissection. Emergency surgery was required in 32 patients. Additional procedures such as partial or complete arch replacement, coronary artery revascularisation or mitral valve repair were performed in 53 patients. In all there were eight (5.3%) early deaths (1.3% for elective and 12.2% for emergency operations and dissections), and 13 late deaths during a follow-up period varying from 1 to 209 months (mean 79). There were no early deaths in the 109 electively operated patients since 1986. The actuarial survival at 5, 10 and 15 years was 92.4%, 87.2% and 70.4%, respectively. Nine patients (7 of whom are Marfan patients) required re-operation (aortic valve replacement or re-do repair) 4 months to 12 years (mean 5.4) after operation. There were no early deaths in this group. The probability of freedom from re-operation at 5 and 10 years was 95.7% and 90.7%, respectively.

There were no instances of infective endocarditis or thromboembolic complications. No anticoagulants were used. Echocardiography showed reduction in left ventricular end systolic and end diastolic dimensions which was maintained throughout the period of follow-up except in those patients who required re-operation. Mild or no aortic regurgitation was demonstrated in 93%, moderate in 5.1% and moderate to severe in one patient who is currently awaiting re-operation.

It is concluded that valve preserving operations are possible in a large proportion of patients with aneurysms of the ascending aorta and that the medium and "long" term results are encouraging.

*By invitation

6. IS RETURN OF ANGINA AFTER CABG IMMUTABLE ?

Paul T. Sergeant, M.D., Eugene H. Blackstone, M.D., Bart Meyns, M.D.*

Leuven, Belgium and Birmingham, Alabama

Discussant: Bruce W. Lytle, M.D.

Since today survival after either surgery or angioplasty seem similar for a wide spectrum of coronary patients, the efficacy of surgery in long term relief of angina assumes higher priority. Therefore time-related return of angina, without infarct or death the same day, was studied in a multivariable parametric analysis of a consecutive series of 9600 patients after primary isolated CABG (Jan./71-Jan./92). The common closing date (Jan./93) follow-up was 99.9 % complete. Extensive arterial revascularisation was used since 1972 with different prevalence over time.

The 1-yr., 5-yr., 10-yr., 15-yr. and 20-yr. freedom from angina was 94%, 82%, 61%, 38% and 21% respectively. A two-phase hazard function was identified. Early return of angina, rapidly declining after two months, was influenced by demographic variables, preoperative anginal status, distribution of coronary disease, vascular comorbidity, but more strongly by procedural (e.g. extensive arterial revascularisation) and institutional variables. Late return of angina, rising after two years and for the whole extent of the follow-up, was influenced by demographic variables, anginal status, left ventricular function, distribution of coronary disease, very strongly by coexisting cardiac and non-cardiac comorbidity (such as obesity, diabetes and preoperative lipid levels), but, in contrast with early return of angina, moderately by procedural variables. The 2-yr freedom from angina for a median patient with 4 distals was 94.7%, 95.5%, 96.0% and 96.3% with 0, 1, 2 and 3 arterial anastomoses. The 15-yr freedom from angina for a median patient with 4 distals was 38.1%, 42.0%, 45.7% and 49.2% with 0, 1, 2 and 3 arterial anastomoses.

Thus early return of angina is minimized by use of procedural techniques such as arterial grafts, but reduction of late angina return requires control of non-cardiac comorbidity.

11:15 a.m. PRESIDENTIAL ADDRESS

Shaping the Revolution: Thoracic Surgeons and Something More.

David B. Skinner, M.D., New York, New York.

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

*By invitation