American Association for Thoracic Surgery
69TH ANNUAL MEETING
MAY
8-10, 1989
Scientific
Program
MONDAY MORNING, May 8, 1989
8:30 a.m. BUSINESS SESSION (Limited to Members)
8:45 a.m. BASIC SCIENCE LECTURER
THE PATHOGENESIS OF ATHEROSCLEROSIS
Russell Ross, Seattle,
Washington
9:30 a.m. SCIENTIFIC SESSION - HYNES BALLROOM
1. Ascending and Aortic Arch Replacement:
Factors Influencing Early and Late Survival
E. STANLEY CRAWFORD,
LARS G. SVENSSON*,
JOSEPH S. COSELLI*,
HAZIM J. SAFI* and
KENNETH R. HESS*
Houston, Texas
Ascending and/or aortic arch reconstruction by
composite valve graft (N = 271), separate valve graft (N = 107), graft only (N
= 233), and other procedures (N = 57) was employed from Jan. 1980 to Oct. 1988
in 668 patients for trauma (N = 5), infection (N = 19), aortitis (N = 44),
Marfan (N = 95), non-Marfan dissection (N = 191), and medial degeneration (N =
314). Of these, 139 were redo operations in patients who had either previous
heart or aortic operations. The 30-day survival was 91%. Factors favoring
increased survival (p<0.05) included asymptomatic aneurysm (276/291, 95%)
and age less than 50 (190/201, 95%). Survival in those with ascending was 92%
(278/301, ascending and arch 89% (242/272), and arch 91% (86/95) and was
similar regardless of operative technique. The independent determinants
predictive of 30-day mortality (p<0.03) were increasing age, severity of
symptoms, diabetes, previous operation, cardiac, and neurologic complications.
After a total of 1057 operations, the entire aorta was replaced in 73, near
total aorta in 30, and the entire thoracic aorta in 117; regardless, late
survival (Kaplan-Meier) was 66% and 56% at 5 and 7 years. Survival of 30-day
survivors according to age was 10-49 years, 78%, 50-74, 71%, and 75-88, 69% (p =
0.0325). Independent predictors of late mortality (p<0.03) were heart
disease, COPD, extent replaced, distal aneurysm, and neurologic events. Of
survivors, 97% wen: in NYHA Class I or II and 93% were free of ascending and/or
arch reoperation at 5 years. Thus, early operation appears justified before
development of symptoms, rupture, or dissection.
*By Invitation
2. Atherosclerosis of the Ascending Aorta and
Coronary Artery Bypass. Pathology, Clinical Correlates and Operative Management
NOEL L. MILLS, CHARLES
T. EVERSON*,
CARL S. RIGBY* and ANDREW M. SCHWARTZ*
Marrero, Louisiana
Analysis of 1735 patients undergoing CABG from
January 1981 through July 1988 revealed 152 patients (8.8%) with mild (79
patients, 4.5%), moderate (39 patients, 2.2%) or severe (34 patients, 1.9%)
ascending aortic atherosclerosis (As Ao Ascl). Distinct pathological patterns
are: I. a lattice of circumferential medial calcification (porcelain aorta);
II. grumous, liquid ASCL in the aortic wall; III. ragged, friable ulcerated
intraluminal disease. A high incidence of stroke in CABG patients with the
severe type of As Ao Ascl prompted development of a new operative technique
that has been used in 12 patients (10 males, 2 females). Ages ranged 53 to 80
years. The "no touch" technique involves no ascending aortic cannulation or
clamping, low flow hypothermic cardiac fibrillation with or without circulatory
arrest, and all vein graft anastomoses placed end to side to IMA(s). The 12
patients had 37 distal IMA and SVG anastomoses and 17 proximal SVG end to side
IMA anastomoses. IMA free flows ranged 130-300 cc/min. There have been no early
or late CVA's or recurrence of angina. Two hospital deaths (drug error and
ruptured aneurysm) were unrelated to the technique. One late death secondary to
ruptured abdominal aneurysm six months postoperatively prompted a review of
patients with severe As Ao Ascl. An inordinately high incidence of significant
carotid disease and abdominal aortic disease (aneurysm and/or occlusive
disease) was discovered. As Ao Ascl must be suspected in (1) all CABG patients
with significant carotid and abdominal aortic disease, (2) aortic wall
irregularity on coronary angiography (3) adhesions between the ascending aorta
and its adventitia, (4) pale appearance of the ascending aorta, and (5) when an
aortic stab wound for cannulation does not bleed appropriately. Diagnosis is
confirmed by aortic palpation during intermittent cava! occlusion prior to
aortic cannulation and by operative echocardiography.
Conclusion: A "no touch" technique that avoids
any manipulation of the ascending aorta and that utilizes the IMA(s) as the
source of blood supply for coronary bypass is an effective method to prevent
aortic clamp injury, trash heart or stroke from severe As Ao Ascl.
*By Invitation
3. Influence of Oxygenator Type on the
Incidence and Extent of Microembolic Retinal Ischemia During Cardiopulmonary
Bypass. Assessment by Digital Image Analysis
CHRISTOPHER I.
BLAUTH*, PETER L. SMITH*,
JOHN V. ARNOLD*, J.
ROGER JACOB*,
RICHARD WOOTTON* and
KENNETH M. TAYLOR*
London, England Sponsored by: Floyd D. Loop, Cleveland, Ohio
We have previously reported the occurrence of
microembolic ischemia in the retina during cardiopulmonary bypass, as revealed
by fluorescein angiography. This method has been extended by digital image
analysis to include quantification of the extent of retinal ischemia, and
applied to a prospective comparative study of 64 patients undergoing elective
coronary operations using either a bubble or a membrane oxygenator. Patients
with diabetes or clinically evident cerebrovascular disease were excluded.
Bypass procedures were standardised in all cases with pulsatile flow and a 40
micron arterial line filter (Pall EC Plus). 30 patients had bypass with a
bubble oxygenator (Harvey H1700) and 34 patients had bypass using a flat sheet
membrane oxygenator (Cobe CML). In each case retinal fluorescein angiograms
were obtained preoperatively and 5 minutes before the end of bypass, and
processed using a digital image analyser (Context Vision GOP-302). Microembolic
perfusion defects were identified by digital subtraction of preoperative and
end-bypass angiograms and their total area was computed.
Results. In the bubble oxygenator group retinal perfusion defects indicative of
microembolism occurred in 30/30 (100%) patients. In contrast 19/34 (56%)patients
in the membrane oxygenator group had normal retinal perfusion, and the
incidence of perfusion defects (44%; 70% confidence limits (CL 34%-54%) was
significantly reduced compared to the bubble group (p<0.001). In addition,
those patients in the membrane group with retinal perfusion defects (n = 15)
had significantly fewer lesions (median 1; 70% CL 1-2) than patients in the
bubble group (median 2; 70% CL 2-2; p<0.04), and also had significantly small
total areas of retinal ischemia (median 0.13mm2; 70% CL 0.10mm2-0.25mm2)
compared to the bubble group (median 0.22mm2; 70% CL 0.21mm2-0.27mm2;
p<0.05). There was no relationship between the extent of retinal ischemia
and bypass time, arterial blood gas concentrations, volume of cardiotomy
suction or donor blood returned to the pump, or recent medication with aspirin.
Inferences. Digital image analysis of retinal fluorescein angiograms may provide a
method of quantifying microembolic ischemia in the central nervous system
during oardiopulmonary bypass. Flat sheet membrane oxygena-tion appears to
provide significant protection against microembolic ishcemia compared to bubble
oxygenation.
10:30 a.m. Intermission - Visit Exhibits
*By Invitation
11:00 a.m. SCIENTIFIC SESSION - HYNES BALLROOM
4. Reoperative Coronary Surgery: Comparative
Analysis of 6840 Primary and 502 Reoperative Coronary Artery Bypass Patients
(CAB)
NEAL W. SALOMON*, J.
EDWARD OKIES,
ALBERTH. KRAUSE,
JOHN C. BIGELOW*,
U. SCOTT PAGE* and
MARK T. METZDORFF*
Portland, Oregon
During an eighteen year period a consecutive
series of 6271 patients (pts) underwent primary and 475 pts underwent
reoperative (reop) CAB. Results were analyzed to determine comparative risk
factors for morbidity as well as early and late survival. The mean patient age
for the reop group was identical to the primary group, 59.2 years (yrs);
however mean age at initial operation for reop patients was 55.2 yrs. Mammary
grafts were done at initial operation in 59% of patients who have had one
operation vs only 45% of patients who subsequently came to reop (p<.01).
Overall operative mortality was 2% (135/6271) for primary pts versus 6.3%
(30/475) for reop pts (p<.01). Patients with a reoperative interval less
than ten yrs had a 4.7% mortality vs 22% if greater than ten yrs between
operations (10/46 pts) (p<.01). Reop pts had a higher incidence of male
gender, ventricular arrhythmias, excessive bleeding, neurologic complications,
prolonged ventilatory support, and intra-aortic balloon pump insertion (all
p<.01). Mean peak CPK-MB was 31 for reop vs 17 for primary pts (p<.01).
EKG changes of infarction were present in 6.9% of reops versus 3.0% of primary
pts (p<.01). The presence of a patent mammary graft from the initial operation
did not affect reoperative survival. Actuarial survival was 80% vs 90% at five
yrs and 65% vs 75% at ten yrs for reop vs primary CAB pts, respectively
(p<.01). The probability of undergoing reop within five and ten yrs was .020
+/- .003 and .027 +/- .004, respectively. At five yrs postop moderate to severe
angina had recurred in 24% of reop pts but only 13% of primary pts (p<.01).
Patients undergoing reop CAB represent a substantially higher risk sub-group
than pts undergoing initial operation in terms of perioperative morbidity,
mortality, decreased long-term survival, and decreased relief of anginal
symptoms.
*By Invitation
5. Favorable Results of Coronary Artery Bypass
Grafting in Patients Older Than 75 Years
KEITH A. HORVATH*,
VERDI J. DiSESA *,
PAMELA S. PEIGH*,
GREGORY S. COUPER*,
JOHN J. COLLINS, JR.
and LA WRENCE H. COHN
Boston,
Massachusetts
There is controversy whether the short and long
term results of coronary artery bypass grafting in elderly patients justifies
performing the procedure. Between January, 1977 and December, 1986, 4580
patients underwent coronary artery bypass grafting of whom 222 (4.9%) were 75
years old or older (mean 77). There were 143 males and 79 females and 139 (63%)
were in New York Heart Association Class IV. 146 patients (66%) had suffered at
least one preoperative myocardial infarction. Myocardial revascularization was
performed under emergency conditions in 17 patients (7.7%). The mammary artery
was used in 43% of cases and 96% of the patients received two or more grafts
(mean numbers of grafts was 2.7). The hospital mortality was 7.1% (17/222)
compared to an operative mortality of 1.4% in the 4,358 patients less than 75
years old. 198 patients discharged from the hospital survived for a mean of 88
months. Actuarial probability of survival was 75% at 48 months and was the same
in patients with ejection fractions less than or greater than 0.40.
Post-operatively 70% of patients were in NYHA Class I or II, and only 21% were
rehospitalized for cardiac related problems. 77% of the patients were free from
angina during the entire follow-up and of those experiencing angina the mean
time from operation to their first episode was 75 months. While elderly
patients have a somewhat increased operative mortality, long term survival and
freedom from angina are excellent and justify continued performance of coronary
bypass grafting in well selected patients over 75 years of age.
*By Invitation
6. Surgical Angioplasty of the Left Main
Coronary Artery
ROBERT A.E. DION*,
ROBERT VERHELST*,
AMIN MATTA *, MICHEL
ROUSSEAU* and
CHARLES H. CHALANT*
Brussels, Belgium
Sponsored by: Mark
Braimbridge, London, England
Critical isolated stenosis of the left main
coronary artery (LM) is currently treated by conventional bypass surgery.
However, this invariably leads to the definitive occlusion of LM, restores only
a retrograde perfusion to a rather extensive myocardial area when a single
bypass graft is constructed, and consumes a non-negligible length of bypass
material. As from June 1985, we performed 20 LM patch plasties in 19 patients.
16 patients were male, age averaged 51 years (38-76 years). LM was approached
either from behind after a curved right-sided aortotomy (10 cases), either
anteriorly (10 cases) after retraction to the left or division (1 case) of the
main pulmonary artery. LM was divided longitudinally across the stenosis, the
incision being extended for 2 cms onto the aortic wall: a venous (16 cases) or
pericardial (4 cases) inlay patch was used to close the defect so as to give the
LM a funnel shape. In 4 of the 5 patients aged 60 years or more, LM plasty
failed because of an underestimated local calcifications, and a conventional
bypass graft was needed. One of these patients, a 61-year-old female, developed
early graft failure and underwent 8 months later a successful repeat patch
plasty pericardial using a transpulmonary anterior approach. A 76-year-old
male, suffering from impending infarction, died at surgery: LM plasty had been
attempted in view of the extremely poor quality of the saphenous veins. There
were 2 perioperative myocardial infarctions in the "failure" group. The 16
patients having undergone a successful LM plasty are asymptomatic and all have
resumed a normal activity. The follow-up averages 20 months (4-41 months). A
maximal stress-test combined with a Thallium scintigraphy, performed in all of
them 6 months after the operation, showed no residual ischemia and a normalized
physical capacity. 13 patients consented to a 6 months postoperative
angiographic control, demonstrating an excellent LM patency in all of them.
Surgical patch plasty of LM restores a physiological perfusion of the left
coronary tree, allows subsequent percutaneous coronary angioplasty of the
distal left coronary tree, saves bypass material and can be performed safely.
It should not be attempted if calcifications can be seen on the preoperative
angiogram, in patients above 65 years of age and when the stenosis involves the
distal bifurcation of the LM.
12:00 p.m. Adjourn for Lunch - Visit Exhibits
*By Invitation
