Objectives: Prevalence of early silent bypass occlusion after OPCAB demonstrates a gray zone
and may affect the short-term results. The purpose was to assess predictors of graft
failure prior to discharge by non-invasive multi-slice computed tomography (CT).
Methods: From 01/17 till 08/17, 122 asymptomatic patients after OPCAB underwent CT during
the first postoperative week. In total, 218 arterial and 199 venous grafts were evaluated.
Patients, who underwent postoperative coronary angiography because of suspected perioperative
infarction, were excluded. Two groups (patent (n = 94) vs occluded (n = 28)) could be compared. Cardiovascular risk factors, collateralization of native
vessels using the Rentrop classification, grade of native vessel stenosis, flow and
pulsatile index (PI) were analyzed. Numeric variables presented as median (interquartile
range). Inferential statistics were performed with Mann-Whitney U-test. Nominal and
categorical variables were tested with Fisher-Freeman-Halton exact test.
Results: In 28 patients, at least one occluded graft could be identified with a tendency to
female gender (p = 0.06). The number of distal anastomosis was 3.4 for the patent and 3.6 for the
occluded group (p = 0.31). The use of both internal thoracic arteries was 60.2% in the patent and 62.1%
in the occluded group (p = 0.29). The patency of all arterial grafts was 95.9%, of venous grafts 86%. In detail,
9 occluded arterial grafts and 28 venous grafts were found. For 13 of the occluded
bypasses the decision for an intervention or stenting was made. There were significant
differences in flow and PI with lower flow and higher PI in the occluded group (flow
p = 0.006; PI p = 0.0001). No impact of collateralization or grade of native vessel stenosis on bypass
occlusion could be found.
Conclusion: Early silent graft failure occurred predominantly in venous grafts with a tendency
to female gender. Low flow and high PI measurements ask for a precise evaluation of
the quality of anastomoses.
Table 1 Bypass characteristics
|
Bypass Characteristics
|
patent n = 380
|
occluded n = 37
|
p
|
|
Stenosis grade (target vessel) (%)
|
90 (80 - 95)
|
90 (75 - 99)
|
0.996
|
|
Flow (ml/min)
|
34 (24 - 49)
|
26.5 (18 - 37)
|
0.0064
|
|
Pulsatile Index
|
1.8 (1.4 - 2.3)
|
2.75 (1.7 - 4.1)
|
0.0001
|
|
Collaterals (Rentrop) (%)
|
|
|
0.6225
|
|
- 0
|
320 (84.4)
|
30 (78.9)
|
|
|
- 1
|
12 (3.2)
|
1 (2.6)
|
|
|
- 2
|
14 (3.7)
|
2 (5.2)
|
|
|
- 3
|
33 (8.7)
|
5 (13.3)
|
|
|
Sequential anastomoses (>1) (%)
|
119 (31.4)
|
15 (39.5)
|
0.4808
|
