TUESDAY MORNING, May 12, 1981

8:30 A.M. Scientific Sessions - International Ballroom

16. Management of Acute Myocardial Infarction By Intra-coronary Lysis (ICL) and Subsequent Surgical Revascularization

HANS J. KREBBER*, D. MATHEY*, K. H. KUCK*,

P. KALMAR* and G. RODEWALD*, Hamburg, Germany

Sponsored by: J. Donald Hill, San Francisco, California

With the introduction of ICL for coronary thrombosis into clinical medicine a new regimen for the management of acute M.I. has developed. Patients with acute M.I., admitted within less than 4 hours following the onset of symptoms, are catheterized immediately, and angiography is performed. In the presence of coronary thrombosis recannulation is attempted by local application of streptokinase (55 patients). When recannulation is achieved and the clinical situation is stable, or when no recannulation is achieved and tansmural M.I. develops, the patients are treated medically (40 patients) and surgical revascularization is performed at 4-6 weeks when indicated (4 patients). However, when ICL is successful, but symptoms of angina persist, reoccur or early thrombosis is to be expected, aortocoronary bypass surgery is performed immediately. In this last group of 11 patients (8 males, 3 females, mean age 53.3 years) with successfully recannulated coronary arteries (6 x LAD, 4 x RCA, 1 circ.) were surgically revascularized within hours up to 12 days following ICL. One to 4 aortocoronary venografts (mean 1.6 per patient) were implanted according to the extent of the disease. The mitral valve was replaced and a left ventricular aneurysm was resected in 1 patient each. All patients survived and had an uneventful course without signs of reperfusion damage or postoperative M.I. The behavior of CPKMB levels are comparable to those of patients operated on electively. Ventricular function was improved in more than two thirds of the patients. Early results will be discussed on the basis of angiography.

The staged management of acute M.I. using ICL and subsequent surgical revascularization is a safe method with promising early results as far as preservation of the left ventricular function is concerned.

*By invitation

17. The Optimum in Coronary Revascularization

RICHARD D. WEISEL*, BERNARD S. GOLDMAN,

RONALD J. BAIRD, HUGHE. SCULLY,

LEONARD SCHWARTZ*, MICHAEL J. McLOUGHLIN*,

KEVIN H. TEOH*, PETER R. McLAUGHLIN* and

HAROLD E. ALDRIDGE*, Toronto, Ontario

Early patency rates after aorto-coronary bypass (ACB) surgery are critically dependent on the surgeon's selection of arteries for bypass, and high patency rates may not represent the optimum in coronary revascularization.

One hundred consecutive patients (pts) were recatheterized 6 to 10 days after ACB. The patency rate was 83% (202/243). A multivariate (discriminate) analysis identified three factors which independently influenced early patency: arterial size (from preoperative angiograms and intraluminal probes), arterial quality (assessed pre and intraoperatively) and the surgeon's intraoperative prediction of patency. These factors significantly (p<.01) predicted patency rates (%):

One hundred and eighty-nine grafts performed to arteries of good size and quality were designated intraoperatively as primary grafts and fifty-four small, diseases arteries were selected for secondary grafts. The patency rates for primary grafts (94%) were significantly (p<.01) better than for secondary grafts (43%). If only primary grafts had been constructed, the patency rate would have been greater (94%), but the number of patent grafts per patient (1.78) would have been less than in our series (2.02). The difference was more pronounced in pts with triple vessle (TV) than double vessel (DV) or single vessel (SV) disease.

The construction of secondary grafts did not increase peri-operative cardiac injury. Eight myocardial infarctions (new Q waves) occurred in the distribution of the 189 primary grafts (4 were patent) and two infarcts occurred in the distribution of the 54 secondary grafts (1 was patent). The highest postoperative CK-MB value for those patients receiving only primary grafts (24 ± 8 IU/L) was not different than for those patients also receiving secondary grafts (26 ± 7 IU/L).

The construction of secondary as well as primary grafts, reduces the patency rate but produces more patent grafts, without producing myocar-dial injury. Late recatheterization with an assessment of ventricular function will be required to determine whether the performance of secondary grafts improves long term cardiac perfusion. The optimum in early myocardial revascularization is not attainment of the highest patency rate, but the creation of the largest number of patent grafts per patient.

*By invitation

18. Coronary Artery Disease with Minimal Angina - Medical Versus Surgical Therapy

DENIS H. TYRAS, HENDRICK B. EARNER,

GEORGE C. KAISER, D. GLENN PENNINGTON*,

JOHN E. CODD, VALLEE L. WILLMAN and

J. G. MUDD*, St. Louis, Missouri

This study examines the response to therapy of 447 patients with significant coronary artery disease (at least one major coronary artery with>70% stenosis) who had minimal angina (Canadian Heart Association Class 0, I, or II). Patients with left main coronary stenosis, valvular disease or ventricular aneurysm were excluded. Treatment assignment to operation or non-operative care was nonrandom by patient or physician preference. Isolated coronary bypass grafting was performed in 284 patients as initial therapy; of 163 patients initially managed non-operatively, 22 subsequently underwent operation because of increasing angina. Average followup is 38.6 months (range 18-64).

In patients with SVD, only one non-cardiac death and three nonfatal Mis occurred among those either medically or surgically treated. In patients with double- or triple-vessel disease, 3 year cumulative survival was significantly higher in those managed operatively (98.6 ± 0.8% vs 91.5 ± 3.2%, p 0.04). Event-free 3 year survival was also better in surgical multivessel disease patients (90.1 ± 1.9% vs 67.5 ± 4.5%, p 0.001). These data suggest that, even in patients with minimal angina, operative management of double or triple vessel disease leads to better survival and continued angina relief. Angiographic findings of double or triple vessel disease create an anatomic imperative in favor of operative therapy regardless of severity of angina symptoms.

*By invitation

19. Should Coronary Arteries With Less Than 50% Stenosis Be Bypassed?

DELOS M. COSGROVE, FLOYD D. LOOP,

CRAIG L. SAUNDERS*, BRUCE W. LYTLE* and

JOHN R. KRAMER*, Cleveland, Ohio

The unpredictability of progressive coronary atherosclerosis has caused a trend towards grafting arteries with <50% stenosis. To evaluate the patency of these grafts and the effect on the native circulation, 92 patients (80 men and 12 women) with 302 coronary arteries were reviewed. The age range was 34 to 66 years (mean, 51.8 years). Of 226 bypassed arteries, 100 had <50% stenosis. The mean interval between surgery and catheterization was 13 months. Forty-five patients underwent routine postoperative studies; the remainder were symptomatic or had sustained a cardiac event.

Patency rates were similar for grafts placed to arteries with 50%stenosis (79%) and to arteries with >50% stenosis (81%). Forty internal mammary artery grafts (IMA) had a 95% patency; 96.3% to vessels with >50% stenosis and 92.3% to vessels with >50%. Two hundred twenty-six vein grafts had a 77.4% patency, with 76.8% to arteries with 50% stenosis and 78.2% to arteries with >50% stenosis. No difference in patency rates occurred for subsets of vein grafts to the right, circumflex, or anterior descending coronary arteries.

Progressive atherosclerosis (PA) in coronary arteries was defined as an increase in estimated stenosis of at least 20% or progression to total occlusion. PA was demonstrated in 17.5% of 40 nongrafted arteries with <50% stenosis; 63% of 100 grafted vessels with <50% stenosis; and 51.6% of 93 vessels with >50% stenosis. Thirty-three percent had PA when grafted with IMA while 66% had PA when vein grafts were employed (p<0.01). No difference in PA was noted whether grafts were occluded (45%) or patent (57.5%).

We conclude that 1) grafts to arteries with <50% stenosis have patency rates similar to those with >50% stenosis. 2) IMA grafts are associated with a higher patency rate than vein grafts in arteries with <50% stenosis. 3) In <50% stenotic areries, PA is greater in grafted than nongrafted vessels.

INTERMISSION - VISIT EXHIBITS

*By invitation

20. Two-Dimensional Ultrasound and Cardiac Surgery

HENRY M. SPOTNITZ*, New York, New York

Sponsored by: James R. Malm, New York, New York

Although the utility of two-dimensional echocardiography in closed chest patients is well known, its potential advantages in the open chest during cardiac surgery have not been fully explored. Accordingly, two-dimensional echocardiography was employed in 50 patients for anatomical and physiologic "studies during cardiac surgery. Standard, commercially available phased-array echocardiography equipment with a gas sterilized transducer was found to produce surprisingly clear echocardiographic images in the open chest without the need for water paths or conductive gel. Unusual perspectives not permitted by the bony thorax were readily obtained.

Two-dimensional echocardiography detected micro-bubbles entrapped within the left ventricle in 19 patients at the conclusion of cardiac surgery. It facilitated careful planning of a surgical approach across the interatrial septum to cardiac tumors in two patients. It clearly elucidated the relationship between struts of prosthetic mitral valves and the aortic outflow in twelve patients during mitral valve replacement. In 35 patients, alterations in left ventricular ejection fraction during surgery were detected and characteristically related to specific surgical procedures for acquired coronary and valvular heart disease. Increased ejection fraction after surgery for constrictive pericarditis was also demonstrated.

In the closed chest, detection of acute pericardial tamponade and acute mitral insufficiency with preservation of left ventricular function (avoiding cardiac catheterization) were also demonstrated. Increasing left ventricular mass following cardiac transplantation in a single patient was also demonstrated, suggesting a non-invasive method for detecting cardiac rejection.

In summary, two-dimensional echocardiography is extremely useful for definition of anatomic and physiologic changes occurring during cardiac surgery. The potential limitations and demonstrated utility of this method should be familiar to cardiac surgeons working in institutions with access to this modality.

*By invitation

21. Endomyocardial Fibrosis: Early and Late Results of Surgery in 20 Patients

DOMINIQUE METRAS*, ANDRE QUEZZIN COULIBALY*,

KOUAME OUATTARA*, JACQUES CHAUVET*,

ALAIN EKRA * and EDMOND BERTRAND*,

Abidjan, Ivory Coast

Sponsored by: Aldo R. Castaneda, Boston, Massachusetts

Twenty patients with endomyocardial fibrosis (E.M.F.), the largest series reported to date, were operated upon between June 1978 and June 1980. Eleven were male, ages ranged from 6 to 23 years, (mean 13.3 years). There were 7 right ventricle (R.V.) E.M.F., 6 left ventricle (L.V.) E.M.F., 7 bilateral E.M.F. (predominant in L.V. 5, in R.V. 2). The procedure included in all patients endocardectomy (8 R.V., 8 L.V., 4 bilateral) and atrio-ventricular valve replacement with xenograft (9 tricuspid, 11 mitral). Four patients had an additional valvular annuloplasty (2 mitral, 2 tricuspid). There were 4 postoperative deaths (all bilateral E.M.F.): low cardiac output (2), hepatic failure (1), cerebral malaria (1). There was one late death from serum hepatitis. The other patients had a relatively uncomplicated postoperative course. None of the twenty patients had atrio-ventricular block (A.V.B.). The longest followup of the 15 survivors is 28 months (mean 16.7 months). All patients are symptom-free, 3 patients take digitalis and/or diuretics. Ten have been recatheterized from 6 months to 1 year after surgery. Intracardiac pressures, the ventricular cineangiogram, liver and heart-size, returned to normal in patients with L.V. E.M.F.; in R.V. E.M.F., despite clinical improvement, most of these parameters remained abnormal. Of special interest proved (1) recognitions of early type of L.V. E.M.F., and (2) surgical preservation of a thin juxta-annular rim of fibrosis in the R.V. to avoid A.V.B. Surgery is indicated in all patients with L.V. E.M.F., despite greater risk. Early intervention is advised in R.V. E.M.F., to avoid irreversible liver damage and cardiac enlargement.

12:15 P.M. Cardiothoracic Residents' Luncheon

*By invitation