80TH
ANNUAL MEETING
Metro Toronto
Convention Centre
Toronto, Ontario,
Canada, April 30-May 3, 2000
PROGRAM
OUTLINE
MONDAY, MAY 1, 2000
8:00 a.m. BUSINESS
SESSION (Limited to Members)
8:15 a.m. SCIENTIFIC SESSION
(10
minute presentation, 10 minutes discussion)
Constitution
Hall, Metro Toronto Convention Centre
Moderators: Delos
M. Cosgrove, M.D.
Tirone
E. David, M.D.
1. Perioperative Complications After
Living Donor Lobectomy
Richard
J. Battafarano*, Richard C. Anderson*, Brian Meyers*, Tracey J. Guthrie*, Dan
Schuller*, Joel D. Cooper and G. Alexander Patterson, St. Louis, Missouri
Discussant:
Vaughn A. Starnes, M.D.
OBJECTIVE: Clinical lung transplantation has been limited by
the availability of suitable cadaveric lungs. Living donor lobectomy provides
right and left lower lobes from a pair of living donors for each recipient. We
reviewed our experience with living donor lobectomy from July 1994 to August
1999.
METHODS: Fifty-four donor lobectomies were performed. The hospital records of
these 54 donors were retrospectively analyzed to examine the incidence of
perioperative complications.
RESULTS: Median hospital stay for all donors was 5.0 days (range 2.7-12.4).
Twenty-one of the 54 donors (38.9%) had no perioperative complications.
Thirty-three of the 54 donors (61.1%) experienced postoperative complications.
Nine major complications occurred in 8 patients and included bronchial stump
fistula (3), pleural effusion requiring drainage (2), bilobectomy (1),
hemorrhage requiring red cell transfusion (1), permanent phrenic nerve injury
(1), and atrial flutter ultimately requiring electrophysiologic ablation (1).
These 33 donors experienced 46 minor complications including pneumonia (8),
pericarditis (7), dysrhythmia (6), persistent air leak (6), transient hypotension
requiring fluid resuscitation (4), atelectasis (3), subcutaneous emphysema (3),
urinary tract infection (2), loculated pleural effusion (2), ileus (2),
C.difficile colitis (1), rupture of saline breast implant (1), and severe
contact dermatitis secondary to adhesive tape (1). There were no post-operative
deaths and only 1 donor required surgical re-exploration.
CONCLUSIONS: Donor lobectomy can be performed with low mortality
and remains an important alternative for potential recipients unable to wait
for cadaveric lung allografts. However, morbidity is high and must be
considered when counseling potential living donors.
*By Invitation
2. The Relationship of Hospital Size
and Case Volume to the Cost of Coronary Artery Bypass Surgery
David M. Shahian, Gerald J. Heatley* and George A.
Westcott*, Burlington, Massachusetts
Discussant:
Timothy J. Gardner, M.D.
OBJECTIVE: This study challenges the concept that higher volume heart surgery
programs are inherently more cost effective.
METHODS: Retrospective administrative and cost data were obtained for all
12,774 patients who underwent isolated CABG at 12 Massachusetts hospitals
during 1995 and 1996. Hospital acute care beds ranged from 220 to 862 (mean
434)) and total (DRG 106 + 107) annual CABG cases per hospital varied from 271
- 913 (mean = 532). Bivariate and multivariate analyses were employed to study
the relationship between the DRG-spe-cific direct cost and a number of patient
(age, gender, acuity class, payer) and hospital (number of beds, annual
DRG-specific case volume, cardiothoracic residency) predictor variables. For
each hospital, we also studied the relationship between changes in CABG case
volume and the corresponding changes in average cost from 1995 to 1996.
RESULTS: Scatterplots revealed a broad range of mean direct CABG cost among
hospitals with comparable case volumes. When hospital beds and annual cases
were analyzed as disaggregate continuous variables, there was no linear
relationship with CABG direct costs (r = -0.05 to +0.07). When hospital size
was grouped into strata and analyzed by ANOVA, the smallest hospitals had the
lowest costs (p = 0.0001). The relationship between case volume strata and
costs showed no consistent pattern. In multivariate analysis, higher patient
acuity class was the most important predictor of cost for each DRG and year
(partial R2 = 0.15 - 0.21). Beds and case volume met inclusion
criteria for each model but added little to the "explanation" of variability R2,
often less than 1%. Finally, there were substantial inter-hospital differences
in the magnitude and direction (direct versus inverse) of their 1995-1996 A
volume versus A cost.
CONCLUSIONS: Within the range of hospital size and case volume
represented in this study, there is no evidence that either variable is related
to the cost of performing CABG. Massachusetts hospitals appear to function on
different segments of different average cost curves, probably related to
variations in quality, patient flow, process efficiency, standardization, and capacity.
*By Invitation
3. Independent Factors Associated with
Longevity of Prosthetic Pulmonar Valves and Valved Conduits
Christopher
A. Caldarone*, Brian W. McCrindle*, Glen S. Van Arsdell*, John G. Coles, Gary
Webb*, Robert M. Freedom* and William G. Williams, Iowa City, Iowa; Toronto,
ON, Canada
Discussant:
Richard A. Jonas, M.D.
OBJECTIVE: Because most studies identifying predictors of pulmonary valve
prosthesis failure (i.e. reoperation) are limited to a single valve type and
vary according to patient age, inter-study comparison requires an assumption
that differences in age are not important. To evaluate the age-dependence of
variables predictive of prosthesis replacement, the following analysis was
conducted:
METHODS: Retrospective analysis of 945 operations in 727 patients undergoing
placement of pulmonary valve prostheses was performed. After age was identified
as a strong independent predictor of valve failure, the database was stratified
into age-based subsets. Predictors of valve replacement were identified in each
subset.
RESULTS: Freedom from valve replacement at 5 years was 81%. For the entire
cohort, significant independent factors associated with decreased time to valve
replacement included: younger age (Hazard ratio: 0.71/log-years), diagnosis
(Hazard ratios: Tetralogy=reference, Pulmonary atresia/ VSD 2.19, Truncus 1.76,
D-transposition 2.60, L-transposition 2.33, tetralogy w/ absent pulmonary valve
1.74, Double outlet right ventricle 3.57, Pulmonary stenosis 1.03, Pulmonary
atresia/intact septum 1.90), type of prosthesis (Hazard ratios: Pulmonary
homograft conduit=reference, aortic homograft conduit 1.82, pulmonary or aortic
homograft implant 2.21, porcine valve conduit 1.80, porcine valve implant 1.59,
Polystan conduit 3.39, Pericardial valve implant 1.90), and time-dependent
requirement for pulmonary valve stent placement. Important predictors of valve
failure varied among age groups: Age less than 3 months: valve type; Age 3
months to two years: smaller normalized valve prosthesis size; Age 2 years to
13 years: gender, smaller normalized valve prosthesis size, placement of
endovascular stents, and valve type; Age 13 years to 65 years: smaller
normalized valve prosthesis size, placement of endovascular stents, and
increased number of previous valve placements.
CONCLUSIONS: There is a significant interaction between age and
the effects of diagnosis, valve type, and size on prosthetic pulmonary valve
longevity.
*By Invitation
4. The Batista Procedure Is Not an
Alternative to Cardiac Transplantation
Anders
Franco-Cereceda, Patrick M. McCarthy, Eugene H. Blackstone, Katherine J.
Hoercher*, Jennifer A. White*, James B. Young* and Randall C. Starling*,
Cleveland, Ohio
Discussant:
Gianni Angelini, M.D.
OBJECTIVE: We prospectively investigated partial left
ventriculectomy (PLV; Batista procedure) to assess suitability as an
alternative to cardiac transplantation (Tx).
METHODS: From May 1996 until December 1998, 62 patients (pts) had PLV, with
mitral valve repair (MVR) in 95% (mean mitral regurgitation [MR] 3.0±1.0; only
26% had 4+ MR).
RESULTS: Survival and freedom from failure (Class IV CHF) are shown in the
table. Despite extensive interrogation of preoperative variables, including MR,
only higher peak O2 consumption was predictive of 3-year freedom
from failure.
CONCLUSIONS: PLV is associated with a high risk of early failure
which was largely unpredictable and not related to preoperative MR. Early and
late failures preclude use of PLV as an alternative to Tx. Less traumatic
methods to reduce LV wall stress in more selected pts may improve upon these
results.
|
|
30 days
|
3 mos
|
12 mos
|
24 mos
|
36 mos
|
Survival
|
99%
|
94%
|
76%
|
64%
|
53%
|
|
Freedom
from failure
|
81%
|
72%
|
57%
|
48%
|
42%
|
|
Class IV
risk/month
|
8.4%
|
4.3%
|
1.9%
|
1.2%
|
1.0%
|
9:35 a.m. Andrew
G. Morrow Research Scholar Presentation
Stephen
C. Yang
Johns Hopkins University School of
Medicine
9:40 a.m. 47th Evarts A. Graham
Memorial Traveling Fellowship Presentation
Anders
Franco-Cereceda
Stockholm,
Sweden
9:45 a.m. INTERMISSION - VISIT EXHIBITS
1999-2000 AATS Graham
Fellow
*By Invitation
10:30 a.m. SCIENTIFIC SESSION
Constitution
Hall, Metro Toronto Convention Centre
Moderators: James
L. Cox, M.D.
Tirone
E. David, M.D.
5. Persistent
Left Ventricular Hypertrophy Influences Survival Following AYR in Patients with
the Medtronic Freestyle Stentless Bioprosthesis
Dario
F. Del RizzcA Ahmed Abdoh*, Paul Cartier*§, Donald D. Doty§
and Stephen Westaby5, Winnipeg, MB, and Quebec City, PQ, Canada;
Salt Lake City, Utah; Oxford, United Kingdom
Discussant:
David J. Wheatley, M.D.
OBJECTIVE: Small non-randomized cohort series have suggested that the superior
hemodynamic performance of Stentless valves confers a survival advantage to
patients undergoing AVR, when compared to conventional stented and mechanical
devices. It has been suggested that this difference may be related to better
regression of LVH. We hypothesize that persistent LVH is associated with
decreased survival following AVR.
METHODS: We examined 1173 patients who underwent AVR with the Medtronic Freestyle
Stentless valve from 1992-1997 by subcoronary (846),miniroot(103), or
full root(224) techniques. The series had 54.9% males, 73.5% with NYHAIII/IV
symptoms, and 35.1% of patients had concomitant CABG surgery. As was the
dominant lesion in 40.7%.
RESULTS: Cox's proportional hazards model identified age and post-op LV mass
index (LVMI), expressed as continuous variables, as important determinants of
long-term survival. There was an incremental increased risk of death of 8% for
each year of age(HR 1.08, 95% CI 1.03-1.12, p < 0.001) and for every
increase in LVMI of 1 gm/m2 the risk of death increased by 1% (HR
1.01, 95% CI 1.004-1.012, p < 0.001). Multiple linear regression analysis
revealed that LV mass regression was influenced by LVMI at surgery (p < 0.001),
proir MI (p = 0.04), history of carotid stenosis (p = .02), and systemic
hypertension (p = 0.01). Indexed EOA (EOA )was also an important predictor of
LVMI. If EOA, remained < 0.8 cm2/nr at 3-years post-op,
LVMI remained at 95.5 ± 26.5% of baseline (i.e. < 5% reduction). In sharp
contrast, if EOA, was > 0.8 cm2/m2 there was nearly a
25% reduction in LVMI (p < 0.001) as compared to LVMI immediately post-op.
CONCLUSIONS: The data demonstrate that persistent LVH despite
surgical correction places patients at increased risk of mortality following
AVR. Persistent LVH is strongly influenced by baseline LVMI, hypertension, and
the hemodynamic performance of the prosthesis. The data argue that earlier
intervention, treatment with antihypertensive drugs, and careful attention to
patient-prosthetic mismatch may have important prognostic implications to the
patient.
§Authors have a relationship with Medtronic
*By Invitation
6. Prosthesis Size and Mortality After
Aortic Valve Replacement: a Multi-Institutional Meta-Analysis
Eugene
H. Blackstone, Eric G. Butchart*, Delos M. Cosgrove, W.R. Eric Jamieson, John
H. Lemmer, D. Craig Miller and Akiko Chai*, Cleveland, Ohio; Cardiff, Wales,
United Kingdom; Vancouver, BC, Canada; Portland, Oregon; Stanford and Irvine, California
Discussant:
David H. Adams, M.D.
OBJECTIVE: It has been suggested that larger aortic prostheses, with lower
trans-prosthesis gradients, are associated with superior survival. This large
multi-institutional study was undertaken as a definitive investigation of the
relation between prosthesis size and survival.
METHODS: Pooled data for 6610 AVRs from 6 institutions provided 40,415
patient-years of follow-up for analysis, mean 6.5±4.5 years, maximum 20 years,
with 25% followed >10 years. 3561 prostheses were porcine xe-nograft, 1222
bovine pericardium, 1730 mechanical, and 97 allograft. 491 were manufacturer's
labeled size 19. Prosthesis size was expressed as labeled size (mm), indexed
orifice area (IOA, cm2/m2 BSA), and standardized size
(Z-value, number of standard deviations [SDs] from mean normal AV size based on
BSA). 12.5% of patients received a prosthesis with IOA <1.25 cm2/m2.
18% received a prosthesis between -2 and -5 SDs (Z-value) below normal.
Multivariable analyses identified factors associated with use of smaller
prostheses, and hazard function analysis quantified the influence of prosthesis
size on survival, adjusted for valve type, clinical and operative variables.
RESULTS: Smaller prostheses were placed in women and smaller patients, the
elderly, and patients with aortic stenosis (all P<.0001). 30-day mortality
was 4.4%. Risk factors included higher NYHA class P<.0001, previous AVR
P<.0001, and concomitant CABG P=.002. Labeled prosthesis size (P=.6), IOA
(P=.6), and Z-value (P=.9) were not risk factors. 10-year survivals for IOA
<1.5, 1.5-2, and >2 cm2/m2 were 60±2.1%, 54±1.6%,
and 56±1.6%. 10-year survivals for Z-value <-2, -2 to 0, and >0 SDs were
64±2.6%, 53±1.5%, and 56±1.5%. Risk factors for late mortality included older
age, men, aortic regurgitation, previous AVR, and concomitant CABG (all
P<.0001); however, prosthesis size expressed in any fashion had no
demonstrable influence.
CONCLUSIONS: 1) Small prosthesis size does not influence early or
late survival, down to an IOA of 0.8 cm2/m2 or 4 SDs
below normal. 2) Therefore, neither oversizing the prosthesis nor aortic root
enlargement appear necessary for managing most small aortic roots.
11:15 a.m. PRESIDENTIAL ADDRESS
The Innovation Imperative
Delos
M. Cosgrove, M.D.
Cleveland,
Ohio
12:00p.m. ADJOURN
FOR LUNCH - VISIT EXHIBITS
*By Invitation
