WEDNESDAY MORNING, May 9, 1990

7:30 a.m. SIMULTANEOUS SYMPOSIA

SYMPOSIUM I - THE DILEMMA OF ATRIAL FIBRILLATION - Sheraton Ballroom

Moderator: James L. Cox, St. Louis, Missouri

MECHANISMS OF ATRIAL FIBRILLATION

John P. Boineau*, St. Louis, Missouri

THROMBOEMBOLIC COMPLICATIONS OF ATRIAL FIBRILLATION

David G. Sherman*, San Antonio, Texas

SURGICAL TREATMENT OF ATRIAL FIBRILLATION

James L. Cox, St. Louis, Missouri

ATRIAL FIBRILLATION AS A COMPLICATION FOLLOWING CARDIAC SURGERY

Norman A. Silverman, Detroit, Michigan

7:30 a.m. SYMPOSIUM II - MANAGEMENT OF AIRWAY PROBLEMS - Dominion Ballroom - 2nd Floor

Moderator: Joel D. Cooper, St. Louis, Missouri

PANELISTS:

Hermes C. Grille, Boston, Massachusetts

Patrick Gullane*, Toronto, Ontario, Canada

James Harrell*, San Diego, California

*By Invitation

9:00 a.m. SCIENTIFIC SESSIONS - Sheraton Ballroom

26. Emergency Cardiopulmonary Bypass Support in Patients With Cardiogenic Shock and Cardiac Arrest

KIT V. AROM, JODI FISHMAN MOONEY*,

IRVIN F. GOLDENBERG*, DAVID W. MATHIAS*,

ROBERT W. EMERY* and MICHAEL R. MOONEY*

Minneapolis, Minnesota

Emergency percutaneous cardiopulmonary bypass support (ECPS) was instituted in 8 male pts (mean age 59 years) with severe hemodynamic decompensation due to ischemic heart disease refractory to conventional resuscitation measures. ECPS was utilized in the catheterization lab for 3 pts failing cardiopulmonary resuscitation, 3 pts in cardiogenic shock, and in 2 pts for hemodynamic collapse following failed coronary angioplasty (PTCA). ECPS required 3-20 minutes to institute. A 20F cannulae and a 17F cannulae were percutaneously inserted into the femoral vein and artery. Flow rates between 3-5 1/min were achieved with restoration of mean arterial pressure to 70 mmHg (range 50-75). All 8 pts were initially clinically and hemodynamically improved with ECPS. The two pts with failed PTCA underwent successful emergent coronary bypass surgery, one of whom required biventricular assist devices for 3 days. Three pts had anatomy unsuitable for PTCA or bypass, could not be weaned from ECPS, and expired. Three pts had successful coronary bypass surgery. Cannulae removal and femoral vessel repair was performed surgically in all pts. All 5 pts with correctable disease were discharged from the hospital. At follow-up (range 1-10 months, mean 6.2), all 5 pts are free of angina and have resumed to normal activity. In conclusion, ECPS is a powerful resuscitative tool which may stabilize pts with cardiogenic shock and cardiac arrest to allow for definitive intervention.

27. Controlled Reperfusion Avoids Transmural Infarction in Patients After PTCA Failure

FRIEDHELM BEYERSDORF*, KOPPANY SARAI*,

THOMAS WENDT*, FRANK D. MAUL*

and PETER SATTER*

Frankfurt, West Germany

Sponsored by: G.D. Buckberg, Los Angeles, California

Hypothesis: Transmural infarction after emergency revascularization after PTCA failure can be avoided by modification of the initial reperfusion.

Methods: 31 consecutive patients with acute coronary occlusion secondary to PTCA failure were reperfused after operative revascularization under two different conditions: In 23 patients the reperfusate was normal blood and systemic pressure was used ("uncontrolled reperfusion"); in 8 patients the ischemic segment was reperfused during the initial 20 min with a modified blood cardioplegia (substrat-enriched, hyperosmotic, hypocalcemic, alkalotic, diltiazem-containing) at 37 °C and at a pressure of 50 mmHg. Thereafter the heart was allowed to beat empty for additional 30 min before extracorporeal circulation was stopped ("controlled reperfusion"). Assessment of regional contractility (echocardiography, radionuclidven-triculography), EKG, release of CK-MB enzyme and clinical parameters were performed. Regional contractility was graded with a score from 0 (nor-mokinesis) to 4 (akinesis) on the 5th postoperative day. Data are mean ± standard deviation.

Results: Preoperative data (age, sex, coronary status) were comparable between groups. However, the interval between coronary occlusion and reperfusion was significantly longer in the controlled reperfusion-group (4.0 ± 1.6 vs 2.3 ± 1.0 hr, p < 0.05). Regional contractility returned to normal in all patients treated by controlled reperfusion (wall motion score = 0.8 ± 0.9, normokinesis = 0, slight hypokinesis = 1). In contrast regional contractility remained depressed severely after uncontrolled reperfusion with normal blood (score 2.5 ± 0.8, p < 0.05 vs controlled reperfusion) with only 4/23 patients with a score < 2 (2 = severe hypokinesis). Postoperatively enzymes and EKG were similar in both groups. One patient died of chronic mitral insufficiency in the controlled reperfusion-group, despite complete recovery of wall motion in the PTCA related artery. Conversely 4/23 deaths of uncontrolled reperfusion occurred in patients sustained infarct in the area of coronary occlusion (12 vs 17%, p>0.05).

Conclusions: These preliminary clinical results indicate that transmural infarction can be avoided if the composition of the reperfusate and the conditions of reperfusion are controlled during the initial reperfusion. Further clinical studies comparing controlled and uncontrolled reperfusion after acute coronary occlusion in a large cohort of patients are necessary.

*By Invitation

28. A Clinical Trial of Warm Induction Glutamate-Aspartate Blood Cardioplegia for Urgent Revascularization

KEVIN H. TEOH*, JOAN IVANOV*,

RICHARD D. WEISEL, DONALD A.G. MICKLE* and the

CARDIOVASCULAR SURGEONS AT THE TORONTO

GENERAL HOSPITAL Toronto, Ontario, Canada

Although the results of elective coronary artery bypass grafting (CABG) are excellent, patients (pts) who require urgent CABG because of uncontrolled angina face an increased risk. Metabolic resuscitation prior to urgent CABG may reduce the risks.

One hundred and ten pts requiring urgent CABG were randomized to receive either blood cardioplegia (CONTROL, 53 pts) or blood cardioplegia enriched with the Krebs cycle intermediates glutamate and asparlate delivered as a warm (37 °C) induction before blood cardioplegia and as a terminal warm infusion (G + A, 57 pts).

The patients required urgent revascularization because of prolonged (> 15 min) rest angina resistent to nitroglycerine in the coronary care unit (65 pts), pain persisting after a myocardial infarction (36 pts), or complications at catheterization (9 pts). Eighteen of these pts required an intraaortic balloon pump (IABP) preoperatively to control pain.

RESULTS: G + A blood cardioplegia reduced the amount of CK-MB released postoperatively.

CK-MB (mmol/L)	2 hrs.	24 hrs	30 hrs
CONTROL	39 ± 9	41 ± 9	20 ± 2
G + A	24 ± 2*	23 ± 2*	12 ± 1*

*Different than CONTROL p < 0.05

The perioperative mortality (40%) and the incidence of postoperative low output syndrome (LOS, the need for inotropic support or IABP, 9%) was not reduced with G + A in the entire group. However, LOS was reduced in patients who had left main stenosis (CONTROL 17%, G + A 0%, p < .05) and those who had impaired preoperative ventricular function (ejection fraction < 40%, CONTROL 40%, G + A 29%, p < .05).

CONCLUSION: Blood cardioplegia provided excellent protection for patients requiring urgent revascularization, but the addition of glutamate and aspartate during a warm induction and terminal "hot shot" further reduced perioperative ischemic injury. Low output syndrome was reduced only in high risk patients.

*By Invitation

29. Impact of Unstable Angina on Operative Mortality at Varying Intervals Following Myocardial Infarction

JACK J. CURTIS, JOSEPH T. WALLS*,

NAZIH H. SALAM*, RICHARD A. SCHMALTZ*,

WEERACHAI NAWARA WONG*,

RODNEY J. LANDRENEAU*, THERESA M. BOLEY*

and RICHARD MADSEN* Columbia, Missouri

A retrospective study of patients (pts) undergoing isolated coronary artery bypass grafting following myocardial infarction (MI) was performed to test the hypothesis that the anginal syndrome i.e., stable or unstable, is a major predictor of operative mortality. Unstable angina was defined as persisting chest pain following MI or chest pain at rest and crescendo angina in pts more remote from their MI. There were 1,488 pts with an age range of 29-90 (mean 61) reviewed. There was no significant difference in the operative mortality in pts who had experienced a prior MI, 38 of 840 (4.5%) and those who had not, 26 of 634 (4.1%), p = 0.65. However, when pts were grouped according to the timing of operative intervention and recency of MI, a very significant trend of operative mortality was observed as detailed in the table below (p<.001).

OPERATIVE MORTALITY
Time from MI	Stable Angina	Unstable Angina	Total
0 hr - 1 day	0/4 (0.0%)	6/25 (24.0%)	6/29 (20.7% )
1 day - 1 week	0/3 (0.0%)	8/87 ( 9.2%)	8/90 ( 8.9% )
1 - 3 weeks	1/27 (3.7%)	5/95 ( 5.3%)	6/122 ( 4.9% )
3 wks - 3 months	1/100 (1%)	5/102 ( 4.9%)	6/202 ( 2.9% )
> 3 months	0/184 (0.0%)	12/213 ( 5.6%)	12/397 ( 3.02%)
No MI	4/265(1.5%)	22/369 ( 5.9%)	26/634 ( 4.1% )

Ligistic regression analysis of multiple risk factors including recency of MI, age, sex, ejection fraction, left main coronary artery stenosis and the presence of unstable angina revealed that unstable angina was the most important predictor of operative mortality (p<.001). We conclude that while operative mortality is increased in pts undergoing coronary artery bypass grafting with a recent MI, this is secondary to ongoing or intermittent myocardial ischemia as generally reflected in the clinical syndrome of unstable angina. In this study we observed that pts with a recent MI (<3 months) who were stable have a mortality of 1.5% while all pts without prior MI have a mortality of 4.1%.

INTERMISSION - VISIT EXHIBITS

*By Invitation

11:00 a.m. SCIENTIFIC SESSIONS - Sheraton Ballroom

30. Extracorporeal Membrane Oxygenation for Peri-Operative Support in Pediatric Heart Transplantation

MARK E. GALANTOWICZ* and

CHARLES J.H. STOLAR*

New York, New York

Sponsored by: Thomas C. King, New York, New York

Extracorporeal membrane oxygenation (ECMO) has demonstrated effectiveness for cardiopulmonary support in a variety of clinical situations. This report reviews the cases of ECMO used as an adjunct to pediatric cardiac transplantation collected from the International ECMO Registry, the International Society for Heart Transplantation Registry, and Combined Registry of Mechanical Ventricular Assist Devices and Total Artificial Hearts, as well as case reports.

Twenty children, 7 days to 17 years old, with cardiac failure refractory to conventional therapy underwent ECMO support for 6 - 192 hours. In four, ECMO was used as a bridge to transplantation. In ten, ECMO facilitated resuscitation of the cardiac allograft in the immediate post-operative period. In six, ECMO complemented therapy for severe rejection in the late postoperative period.

ECMO successfully bridged four patients to cardiac transplantation without related morbidity. Subsequently, three patients died of allograft failure and one survived.

The patients in the immediate post-transplant group were placed on ECMO within 24 hours post-operatively. Four of the ten patients are long-term survivors. Three patients were placed on ECMO in the operating room. They, like all the deaths in this group, had irrecoverable cardiac allograft function.

In the rejection group, patients were placed on ECMO one to eleven months post-transplantation. Three of the six patients survived. The deaths were due to intractable cardiac allograft dysfunction.

Cannulation sites were thoracic (10), cervical (7), and femoral (3). Complications included mediastinal bleeding requiring re-exploration (4), renal insufficiency (7), neurologic injury (5), and significant infection (3).

Twelve of twenty patients survived ECMO, seven of whom were long-term survivors with excellent cardiac allograft function.

The pediatric heart transplant recipient may be salvaged by the cardiac support capability of ECMO for one or more indications including: bridging to transplantation, supplementing immediate post-operative cardiac allograft resuscitation, or as an adjuvant therapy for treating a rejecting heart. Adequate functional recovery can be anticipated in some patients so treated, but there is significant associated morbidity and mortality in these desperately ill children.

*By Invitation

31. Pediatric Heart Transplantation Following Surgery Involving the Pulmonary Arteries

MATTHEW M. COOPER*, LASZLO FUZESI*,

LINDA J. ADDONIZIO*, DAPHNE T. HSU*,

CRAIG R. SMITH* and ERICA. ROSE

New York, New York

A prohibitive perioperative mortality has been previously ascribed to pediatric heart transplantation following palliative surgery for congenital heart disease (CHD) involving the pulmonary arteries. Of 40 children who have undergone heart transplantation at our institution since 1984, 6 (15%; mean age 9 ± 3 years; range 1-18 years) have previously undergone such surgery: first stage Norwood procedure for hypoplastic left heart syndrome (1), right ventricle (RV) to pulmonary artery (PA) conduit for corrected transposition of the great vessels with pulmonary stenosis (PS) (1), Waterston shunt for tricuspid and pulmonary atresia (1), PA banding followed by Fon-tan procedure for univentricular heart with double inlet left ventricle (1), atrial septectomy and PA banding for univentricular heart with mitral atresia (1), and classical Blalock-Taussig shunt for A-V canal with PS (1). All patients were transplanted successfully.

At operation, individualized pulmonary arterial reconstruction was employed including angioplasty (with and without pericardial patches) and use of a previously created RV-PA conduit. All patients had RV-PA gradients postoperatively (mean 17 ± 6 mmHg; range 2-46 mmHg) with a tendency for these gradients to decrease with time. Two patients developed critical RV failure postoperatively, one of whom required support with ex-tracorporeal membrane oxygenation (ECMO).

Techniques borrowed from the repair of congenital cardiac lesions can be applied to subgroups of children undergoing heart transplantation. Additional length of donor aorta and PA should be harvested for possible use in designing PA connections. Previous palliative surgery involving the pulmonary arteries with associated complex PA anatomy is not of itself an insurmountable obstacle to successful heart transplantation.

*By Invitation

32. Intermediate Term Results of Infant Orthotopic Cardiac Transplantation From Two Centers

CARL L. BACKER*, VINCENT R. ZALES*,

HAROLD L. HARRISON*, FAROUK S. IDRISS

and CONSTANTINE MAVROUDIS

Chicago, Illinois

Infant orthotopic cardiac transplantation (OCT) has been established for patients with conventionally untreatable forms of congenital heart disease. The purpose of this study is to review the combined experience and intermediate term results of infant OCT from Children's Memorial Hospital, Chicago, and Kosair Children's Hospital, Louisville.

From June 1986 through October 1989, 17 OCT were performed in 16 patients. Fourteen had variants of hypoplastic left heart syndrome, 1 had anomalous origin of the left coronary artery. One patient with severe endocardia! fibroelastosis had extracorporeal membrane oxygenation as a bridge to transplantation. Immunosuppression included Cyclosporine, Im-uran and corticosteroids with an effort to wean the steroids by 6 months to 2 years.

Three early deaths resulted from technical errors in 2, and rejection in 1 patient at 3 days. Technical refinements to decrease the ischemic time have improved operative results. Two late deaths occurred, one at 2 months from rejection and one unexplained at 14 months. The remaining 11 patients are surviving 5 to 40 months (mean 14 months) after 12 transplants. Rejection surveillance in the first 6 months continues by clinical signs supplemented by echocardiography, EKG, and cell cycle analysis; endomyocardial biopsy is used after 6 months of age. Twelve episodes of suspected rejection in 8 patients were treated with I.V. Solumedrol in all and OKT3 rescue therapy in 2. One patient underwent successful retransplantation at 15 months for chronic rejection. Serious post-transplant infections including endocarditis, meningitis, and colonic perforation were successfully treated in 3 patients. Subjectively, their quality of life is excellent as documented by normal growth and developmental milestones and a low hospital readmission rate (< 2 episodes per patient per year).

These encouraging intermediate term results warrant continued application of infant OCT for severe forms of congenital heart disease.

12:00 p.m. ADJOURN FOR LUNCH

*By Invitation