84^th ANNUAL MEETING

April 25-28, 2004

Metro Toronto Convention Centre

Toronto, Ontario, Canada

PROGRAM

MONDAY, APRIL 26, 2004

7:45 a.m. Business Session

(Limited to Members Only)

8:00 a.m. SCIENTIFIC SESSION

(8 minutes presentation, 12 minutes discussion)

North Bldg., Hall C, Metro Toronto Convention Centre

Moderators: Joel D. Cooper

Irving L. Kron

1. The Impact of Pre- and Post-Operative Atrial Fibrillation on Outcome After Mitral Valvuloplasty for Non-Ischemic Mitral Regurgitation

¹Ko Bando, Hitoshi Kasegawa*, Yukikatsu Okada*, Tomoki Shimokawa*, Michinori Nasu*, Mitsuhiro Hirata*, Akiko Kada*, Osamu Tagusari, Junjiro Kobayashi*, Toshikatsu Yagihara*, Soichiro Kitamura; Osaka, Japan, Tokyo, Japan, Kobe, Japan, Kanagawa, Japan

Discussant: Kevin D. Accola

OBJECTIVE: We sought to determine the impact of pre- or post-operative atrial fibrillation (AF) on cardiac function, survival and stroke after mitral valvuloplasty (MVP) for non-ischemic mitral regurgitation (MR).

METHODS: From 1992 and 2002,1096 consecutive patients (pts) underwent MVP in 3 centers; 746 pts in sinus rhythm (Group A), 350 pts in atrial fibrillation or flutter preoperatively (Group B). In group B, a concomitant Maze procedure was performed in 155 pts (Group BM) while the remaining 195 pts (Group BN) did not undergo a Maze procedure primarily due to 1) longer duration of AF (> 20 yrs),2) f-wave in lead V1 < 0.1mV, 3) emergency surgery or 4) surgeon preference. The impact of pre- and post-op heart rhythm on cardiac function was determined by serial echocardiographic data.

RESULTS: See table (* by ANOVA, ^†by log rank test). Pts with pre-op AF generally had larger left atrial dimensions (LAD) and reduced left ventricular function (%FS) before surgery. The combination of a Maze procedure, MVP and a smaller LAD resulted in an improved %FS late after surgery (3.6±1.2 yrs post-op) as compared to MVP alone. A Cox hazard model using propensity score revealed that risk factors for late mortality included advanced age (p<0.001), late stroke (p=0.01) and chronic AF after surgery (p=0.02).

CONCLUSIONS: Chronic AF before surgery was associated with dilated left atrium and reduced left ventricular function for pts with MR. The addition of a Maze procedure to MVP helped to improve late cardiac function, improved survival and decreased the incidence of late stroke. However, the best results were achieved by early surgery before the development of AF.

*By Invitation

¹1991-92 Graham Fellow

2. Complications of Lung Transplantation

Bryan F. Meyers*, Maite De La Morena*, Tracey J. Guthrie*, Eric N. Mendeloff, Stuart C. Sweet*, Charles B. Huddleston, Elbert P. Trulock*, Joel D. Cooper, G. Alexander Patterson; St. Louis, MO

Discussant: Shaf Keshavjee

OBJECTIVE: To review the incidence and outcome of lung transplantation complications observed over 15 years at a single center.

METHODS: We conducted a retrospective review from our databases tracking outcomes after adult and pediatric lung transplantation. The 980 operations took place between 7/88 and 9/03 and included 274 pediatric recipients and 706 adult recipients. Bilateral lung (75%), unilateral lung (19%) and living lobar (4%) comprised the bulk of this experience. Retransplantations accounted for 44 (4.5%) of the operations, including a single recipient who was retransplanted twice.

RESULTS: The groups differed markedly by indication for transplantation. The adult transplant cohort included 57% emphysema and 17% cystic fibrosis, while the pediatric cohort included no emphysema and 54% cystic fibrosis. Overall hospital mortality was 90/980 (9.2%) and included 40/274 (14%) of the children and 50/706 (7%) of the adults. Despite an early survival advantage in adults, the overall survival curves did not differ between adults and children (p=.05). The freedom from bronchiolitis obliterans syndrome (BOS) at 5 and 10 years was 42% and 14% for adults and 46% and 30% for children (p=0.4). The main causes of death for adults were BOS (47%), respiratory failure (12%) and infection (11%); while the causes of death in children were BOS (31%), infection (30%) and respiratory failure (21%), (p<0.01). Post-transplantation lymphoproliferative disease was diagnosed in 12% of pediatric recipients and 6% of adults, (p<0.01). The frequency of patients treated for airway complications did not differ between adults and children (8.4% versus 10.9%, p=0.2). The frequency of early graft dysfunction did not differ between children (17.9%) and adults (20.5%) despite uniform use of cardiopulmonary bypass in children.

CONCLUSIONS: These single-center results highlight the major complications faced after lung transplantation. Despite differences in underlying diagnoses and specific operative techniques, the two cohorts of patients experienced remarkably similar outcomes.

*By Invitation

3. Increasing Duration of Deep Hypothermic Circulatory Arrest is Associated with an Increased Incidence of Postoperative Electroencephalographic Seizures

J William Gaynor, Susan C. Nicolson*, Gail P. Jarvik*, Gil Wernovsky*, Lisa M. Montenegro*, Nancy B. Burnham*, Diane M. Hartman*, Andy Louie*, Thomas L. Spray, Robert R. Clancy*; Philadelphia, PA, Seattle, WA

Discussant: Ross M. Ungerleider

OBJECTIVE: Electroencephalographic (EEC) seizures have been shown to occur in up to 20 % of neonates undergoing the arterial switch operation for transposition of the great arteries (TGA) and are associated with adverse long-term neurodevelopmental sequelae. The contemporary incidence of postoperative seizures after repair of other cardiac defects in neonates and infants is not known.

METHODS: A single institution prospective study of 178 patients ≤ 6months of age undergoing cardiopulmonary bypass (CPB) with or without deep hypothermic circulatory arrest (DHCA) was conducted from September 2001 to March 2003 to identify postoperative seizures assessed by 48-hour continuous video-EEC monitoring.

RESULTS: Cardiac defects included hypoplastic left heart syndrome (HLHS) or variant (n = 60), tetralogy of Fallot (TOF) (n = 24), ventricular septal defect (VSD) (n=22), TGA with or without a VSD(n = 12), other functional single ventricle (n = 14), VSD with coarctation (n = 6), and "other" (n = 40). Median age at surgery was 7 (range 1-188) days and was ≤ 30 days in 110 (62%). DHCA was utilized in 117 patients(66%) with multiple episodes in 9. Median total duration of DHCA was 40 (range 1-90) min.

EEC seizures were identified in 20 patients (11 %). Seizures occurred in 15/110 (14 %) of neonates and 5/68 (7 %) of older infants. Seizures occurred in 11/60 (18 %) with HLHS or variant, 1/12 (8 %) with TGA, and 1/24 (4 %) of patients with TOF. By stepwise logistic regression analysis once increasing duration of total DHCA (p=0.04l) was considered, no other variable improved prediction of occurrence of a seizure. Patients with DHCA duration >40 min had a significantly increased incidence of seizures (14/58, 24.1%) compared to those with DHCA duration ≤ 40 min (4/59, 6.8%), p=0.043. The incidence of seizures for patients with DHCA duration ≤ 40 min was not significandy different from those in whom DHCA was not utilized (2/6l, 3.3 %),p>0.1.

CONCLUSIONS: In the current era, continuous EEC monitoring demonstrates early postoperative seizures in 11% of a heterogeneous cohort of neonates and infants with complex congenital heart defects. Only increasing duration of DHCA could be identified as a predictor of seizures. However, the incidence of seizures in children when the duration of DHCA was ≤ 40 min was similar to that identified in infants undergoing continuous CPB alone.

*By Invitation

4. Incomplete Revascularisation During Opcab Surgery Is Associated With Reduced Mid-term Event Free Survival

Massimo Caputo*, Barnaby Reeves*, Chanaka Rajakaruna*, Hazaim Alwair*, Kirkpatrik Santo*, Gianni Angelini; Bristol, UK

Discussant: Paul T. Sergeant

OBJECTIVE: To estimate the rate and effects of incomplete myocardial revascularisation on mid-term clinical outcomes in patients undergoing OPCAB surgery.

METHODS: Data were extracted from a prospective database for all patients with double or triple vessel disease who had OPCAB surgery between April 1996 and November 2002. Patients were classified as having incomplete revascularisation when the number of distal anastomoses was less than the number of diseased coronary segments. Deaths were identified from the UK NHS Central Registry. Cardiac-related events included: recurrency of symptoms of angina (CCS class>1) or dyspnoea (NYHA class>2), myocardial infarction, heart failure and need for repeat revascularisation.

RESULTS: During the study period 1401 patients underwent OPCAB surgery, and of these, 15.8% (191) had incomplete revascularisation Patients with incomplete revascularisation had more preoperative risk factors; compared with those with complete revascularisation. They were more likely to be female, to have had previous cardiac surgery, COAD, peripheral vascular disease, poorer ejection fraction and congestive cardiac failure, creatinine >150_g/L and higher Parsonnet score. The most common cause for incomplete revascularisation was the presence of small and/or severely diseased artery (70%). Follow-up data were available in 1260 patients (90%). Patients with incomplete revascularisation were more likely to die and to experience cardiac-related events compared with patients widi complete revascularisation. Unadjusted hazard ratios for survival and event-free survival (Figure) were 2.58 (95% CI 1.59 to 4.20, p<0.001) and 1.65 (95% CI 1.42 to 1.90, p<0.001) respectively, and 1.85 (95% CI 1.14 to 3.00, p<0.01) and 1.68 (95% CI 1.39 to 2.03, p<0.001) respectively after adjusting for preoperative risk-factors.

CONCLUSIONS: In this study the rate of incomplete revascularisation in OPCAB surgery is similar to that reported in the literature for conventional on-pump coronary surgery. Our data confirm the importance of completeness of revascularisation on survival and event-free survival.

9:30 a.m. Thoracic Surgery Foundation for Research and Education

John R. Benfleld, President

9:35 a.m. INTERMISSION - VISIT EXHIBITS

North Bldg., Exhibit Hall

Metro Toronto Convention Centre

*By Invitation

10:20 a.m. SCIENTIFIC SESSION

(8 minutes presentation, 12 minutes discussion)

North Bldg., Hall C, Metro Toronto Convention Centre

Moderators: Tirone E. David

Irving L. Kron

5. Anastomotic Complications After Tracheal Resection: Prognostic Factors and Management

Cameron D. Wright, Hermes C. Grille, John C. Wain, Dean M. Donahue*, Henning A. Gaissert*, Daniel R. Wong, Douglas J. Mathisen; Boston, MA

Discussant: Ernio Angela Rendina

OBJECTIVE: Anastomotic complications after tracheal resection (separation, stenosis or granulations) cause significant morbidity. We sought to identify prognostic factors for early anasto-motic complications following tracheal resection and to report the results of management of these complications.

METHODS: Retrospective single institution review between 1975 and 2003 of 787 tracheal resection and reconstruction operations. Multivariable logistic regression analysis was used to identify important variables associated with anastomotic complications.

RESULTS: Of 787 patients, 70 (9%) developed anastomotic complications (AC). The following variables were not associated with AC: steroid use, diabetes, hemoglobin level, height, body mass index >30, incision (cervical, mediastinal or transthoracic) and earlier operation(<1990) . Univariable analysis indicated the following variables were associated with AC: males (p=.05), laryngotracheal anastomosis (versus tracheo-tracheal) (p=.02), preop stoma (p=.0003), need for tracheostomy at end of operation (p=.0057), reoperation (p<.0001), postintubation stenosis (PITS) as the reason for operation (versus tumor or idiopathic stenosis) (p=.005), age <17 (p=.002), length of resection >4cm (p=.0004) and need for a release procedure (p<.0001). Multivariable analysis revealed 4 variables associated with AC: reoperation (Odds Ratio (OR) 2.6, p=.004), PITS (OR 2.4, p=.03), length >4cm (OR 1.8, p=.04) and need for release (OR 2.9, p=.002). Patients who had an AC had a greater risk of death (6/70, 9%) than those who did not (5/717,0.1 %) (p< .0001). Of the 64 patients who survived an AC, 37 had a good airway at the end of treatment by means of a reresection (11 patients) or by temporary stenting with a T tube (26 patients). The remaining 27 patients required long-term T tubes or a tracheostomy. The length of stay was only minimally longer in patients with AC (11.5 d) than in those without complication (8 d).

CONCLUSIONS: Patients who have reoperations, resections >4cm, PITS or who require a release are at elevated risk for developing an anastomotic complication after tracheal resection and reconstruction. The risk of death after tracheal resection is markedly increased in the presence of an anastomotic complication. Most patients can be returned to a good airway after an anastomotic complication by either reoperation or temporary stenting with a T tube.

6. Results of Surgery in Acute Type A Aortic Dissection: the IRAD (International Registry of Acute Aortic Dissection) Experience

Santi Trimarchi*, Christoph Nienaber*, Vincenzo Rampoldi*, Truls Myrmel*, Toru Suzuki, Rajendra H. Menta, Eduardo Bossone, Jeanna Cooper*, Dean Smith*, Lorenzo Menicanti*, Alessandro Frigiola*, Jae K. Oh, Michael G. Deeb, Eric M. Isselbacher*, Kim A. Eagle*; S. Donate Milanese, Italy, Rostock, Germany, Tromso, Norway, Tokyo, Japan, Rochester, MN, Ann Arbor, MI, Boston, MA

Discussant: Joseph E. Bavaria

OBJECTIVE: Surgical results for acute type A aortic dissection (AAD) reported in different experiences of single centers or surgeons evidences high variability, ranging from 7% to 30%. The International Registry of Acute Aortic Dissection (IRAD), collecting patients in 18 referral centers world-wide, provides a preoperative risk stratification scheme and a real average surgical mortality for AAD in the current era.

METHODS: A comprehensive analysis of 290 clinical variables and their relation to surgical outcomes on 526 out of 1032 patients (mean age 59.7±13.6yrs, males 69.9%) enrolled in the IRAD from 1996-2001 was completed. Extracted cases, categorized according to risk profile, were defined unstable (group I) in presence of cardiac tamponade, shock, CHF, CVA, stroke, coma, myocardial ischemia and/or infarction, ECG's with new Q's or ST elevation, acute renal failure, or mesenteric ischemia/infarction at surgery. Patients without such preoperative conditions were categorized as stable (group II).

RESULTS: The overall in hospital mortality was 25.1%. In group I was 31.4%, compared to 16.7% in group II (p<0.001). Univariate predictors of surgical mortality (p<0.05 for all) were age (>70 years), female gender, prior aortic dissection, severe or worst ever pain, migrating pain, hypotension (systolic blood pressure (SPB) < lOOmmHg), shock (SBP<80mmhg) or tamponade (SPB<80mmHg), any pulse deficit, congestive heart failure, chest X-ray findings of a widened mediastinum, EGG findings of ischemia/infarction, preoperative neurological deficits, limb ischemia, prolonged time from symptom onset to surgery, surgery delayed and necessity to perform CABG. Multivariate preoperative significant risk factors for operative mortality, are as shown (table) (c-index 0.77, Hosmer-Lemeshow Chi-square = 5.88; degree of freedom 7; p=0.55).

CONCLUSIONS: IRAD evidences that patient selection plays an important role in determining surgical outcomes in AAD patients. Knowledge of significant risk factors for operative mortality can contribute for a better management and a more defined risk-assessment in patients affected by AAD.

*By Invitation

7. Mid-term Clinical Result of Tissue-Engineered Vascular Autografts Seeded with Autologous Bone Marrow Cells

Toshiharu Shin'oka*, Hiromi Kurosawa, Goki Matsumura*, Narutoshi Hibino*, Yuji Naito*, Takashi Azuma*, Akira Murata*, Manabu Watanabe*, Takeshi Konuma*, Masayoshi Natatsu*, Takahiko Sakamoto*; Tokyo, Japan

Discussant: John E. Mayer, Jr.

OBJECTIVE: Prosthetic and bioprosthetic materials currently in use lack growth potential and therefore must be repeatedly replaced in pediatric patients as they develop. Tissue engineering (TE) is a new discipline that offers the potential for creating replacement structures from autologous cells and biodegradable polymer scaffolds. In May 2000 we initiated clinical application of tissue-engineered vascular grafts seeded with cultured cells. However, cell culturing is time-consuming and xeno-serum must be used. To overcome these disadvantages, we began to use bone marrow cells (BMCs), readily available on the day of surgery, as a cell source. The aim of the study was to assess the safety and feasibility of this technique for creating vascular tissue under low pressure system like pulmonary artery or venous pressure.

METHODS: Since August 2000, TE grafts seeded with autologous BMCs have been implanted in thirty-five patients. The patients and/or their parents were fully informed and had given consent to the procedure. Five ml/kg of bone-marrow was aspirated under general anesthesia prior to the skin incision. The polymer tube serving as a scaffold for the cells was composed of a co-polymer of 1-lactide and ε-caprolactone (PCL-PLA, 50:50). This co-polymer is degraded by hydrolysis. The matrix is >80% porous and the diameter of each pore is 100-200 urn. Polyglycolic acid (PGA) woven fabric with a thickness of 0.5 mm was used for reinforcement. Twenty-one TE conduits (TCPC grafts) and fourteen TE patches were used for the repair of congenital heart defects. The patients' ages ranged from 1 to 24 years (median, 5.5 years). All patients underwent a catheterization study and/or computed tomography (CT) scans for evaluation after the operation. The patients received anticoagulation therapy for 3 to 6 months after surgery.

RESULTS: Mean follow-up after surgery was 424 days (maximum, 38 months).There were no thrombosis or obstruction, but two stenosis of TE patch, which was successfully released by baloon angioplasty. One late death at 3 months after TCPC was noted in HLHS patients, which was unrelated to the TE graft function. There was no evidence of aneurysm formation or calcification on cineangiography or CT. All tube grafts were patent, and the diameter of the tube graft increased over time (110 ±7 % of the implanted size).

CONCLUSIONS: Biodegradable conduits or patches seeded with autologous BMCs showed normal function (good patency up to maximum follow-up of 38 months). As living tissues, these vessels may have the potential for growth, repair and remodeling. The TE approach may provide an important alternative to the use of prosthetic materials in the field of pediatric cardiovascular surgery. Longer follow-up is necessary to confirm the feasibility of this approach.

11:25 a.m. PRESIDENTIAL ADDRESS

"Thank You for Being a Doctor"

Joel D. Cooper, St. Louis, Missouri

Introduced by: Tirone E. David

12:15 p.m. ADJOURN FOR LUNCH - VISIT EXHIBITS

North Bldg., Exhibit Hall

Metro Toronto Convention Centre

*By Invitation