A total of 60 patients were included in this study (Table 1). In-hospital mortality was 60.7% (n = 37) with 23 patients surviving to discharge. 52 of 60 (86.6%) patients had cardiogenic shock requiring V-A ECMO (Table 2), 7 of 60 (11.6%) had respiratory failure requiring V-V ECMO and 1 (1.6%) patient had hemorrhagic shock and was placed on V-A ECMO (Table 2). 2 patients were placed on V-A-V ECMO after being initially placed on V-V ECMO and are included in the V-V cohort, as outlined above.
Table 1: Patient Demographics
N=60
|
Non-Survivors
(N total=37)
|
Survivors
(N total=23)
|
p
|
Age (y)
(Mean ± STD)
|
66 ± 1.5
|
52 ± 3.3
|
< 0.001
|
Male
|
22
|
17
|
0.59
|
Female
|
14
|
7
|
0.59
|
BMI (kg/m2)
(Mean ± STD)
|
34 ± 1.4
|
31 ± 1.4
|
0.16
|
Past Medical History
|
|
Diabetes
|
8
|
8
|
0.38
|
Hypertension
|
23
|
13
|
0.30
|
Coronary Artery Disease
|
19
|
6
|
0.037
|
Myocardial Infarction
|
6
|
2
|
0.46
|
Pre-op Coronary artery bypass graft
|
7
|
1
|
0.12
|
Chronic obstructive pulmonary disease
|
5
|
0
|
0.077
|
Asthma
|
5
|
3
|
1.0
|
Congestive Heart Failure
|
14
|
8
|
0.78
|
Peripheral Vascular disease
|
2
|
0
|
0.51
|
Renal Disease
|
7
|
6
|
0.75
|
Dialysis
|
3
|
2
|
1.00
|
Autoimmune Disease
|
6
|
0
|
0.072
|
Malignancy
|
5
|
0
|
0.0768
|
Hyperlipidemia
|
18
|
9
|
0.43
|
Pulmonary Hypertension
|
3
|
1
|
0.64
|
Smoker
|
16
|
7
|
0.41
|
History of Cardiac Surgery
|
8
|
1
|
0.13
|
Legend:
STD: standard deviation
OHT: open heart transplant
Table 2: ECMO Indications, Timing of ECMO Placement, and Type of ECMO
Indications for ECMO
|
Nonsurvivors (N total =37)
|
Survivors (N total=23)
|
P
|
Cardiogenic shock
|
33
|
19
|
0.25
|
Pulmonary Insufficiency
|
3
|
4
|
0.42
|
Other (Hemorrhagic Shock)
|
1
|
0
|
1.00
|
ECMO Type
|
|
VA
|
34
|
19
|
<0.00001
|
VV
|
2
|
3
|
0.38
|
VAV
|
1
|
1
|
1.00
|
Timing of
ECMO Placement
|
|
Pre-operatively Catheterization Laboratory)
|
2
|
5
|
0.09
|
Intra-operative (Operating Room)
|
29
|
14
|
0.24
|
Post-operatively (ICU Post-Operative)
|
6
|
4
|
1.00
|
Legend : VA: venoarterial
VV: venovenous
VAV: Veno-arterio-venous
43 of 60 (71.6%) were placed on ECMO in the operating room (OR), 7 (11.6%) were placed on peripheral ECMO pre-operatively in the catheterization laboratory and 10 (16.6%) were placed on peripheral or central ECMO post-operatively in the intensive care unit (ICU).
14 of 43 (32%) patients, survived having ECMO placed in the operating room. 5 of 7 (71.1%) patients survived pre-operative ECMO placement in the catheterization laboratory. 4 of 10 (40%) patients survived ECMO placement post-operatively in the ICU (Table 2).
33 of the 43 patients who had ECMO placed in the OR were centrally cannulated. 5 of 10 patients who had ECMO placed in the ICU were cannulated centrally because their chest was already open. All catheterization lab patients had peripheral cannulation. Of the 43 patients who had ECMO placed in the OR, 35 received V-A ECMO. 4 of 7 patients who had ECMO placed in the catheterization laboratory required V-A ECMO. 9 of 10 patients placed on ECMO in the ICU were placed on V-A ECMO. There was no significant difference between survivors and non-survivors in time of ECMO implantation, pre-operatively (catheterization laboratory), intra-operatively or post-operatively (in the ICU). All patients who had pre-operative ECMO placed in the catherization then proceeded directly to the OR.
Overall duration of ECMO support in all patients was a median of 5 days (2–8 days). Between survivors and non-survivors, there was no difference in the number of days patients were on ECMO (survivors 4.8 days vs non-survivors 5.7 days, p = 0.33) (table 3). However, we did find that fluid balance was significantly different between survivors and non-survivors. Survivors achieved a net negative fluid balance while on ECMO (-3.5 liters total in survivors vs + 3.4 liters total in non-survivors, p = 0.01) (table 3).
Table 3: ECMO Outcomes
Outcome
|
Non-survivors
(n=37)
|
Survivors
(n=23)
|
p
|
Total Hospital LOS (Days)
|
20±1.5
|
35±4.0
|
0.03
|
ECMO Support (Days)
|
5.7 ± 0.73
|
4.8 ± 0.53
|
0.33
|
Blood Product use while on ECMO (mean units of PRBCs±STD)
|
25 ± 2.3
|
13 ± 2.3
|
0.02
|
Bleeding Events
|
19
(51.3%)
|
8 (34.7%)
|
0.28
|
Net volume Status (L mean±STD)
|
3.4 ± 1.6
|
(-) 3.5 ± 1.5
|
0.01
|
Inotrope/Vasopressor Use
|
20 (54.0%
|
7 (30.4%)
|
0.064
|
eCPR
|
15 (83.3%)
|
3 (16.6%)
|
0.02
|
ECMO on the Go
|
4 (44.4%)
|
5 (55.5%)
|
0.29
|
OHT as salvage procedure
|
0
|
4
|
0.018
|
Legend: LOS: length of stay
STD: standard deviation
OHT: open heart transplant
Of the 23 patients who survived to discharge 2 patients were discharged with an LVAD, with one of those patients ultimately receiving an Orthotropic Heart Transplant (OHT). Of the other 21 patients who survived, 6 underwent OHT, 15 recovered sufficiently for decannulation and discharge. All patients who survived were discharged either to home or a rehabilitation facility, with every patient eventually being transitioned home.
9 of 60 (15%) patients underwent ECMO-on-the-go. 5 of these 9 (55.5%) patients survived. However, this was not statistically different (p = 0.29).
Demographics
Survivors were found to be younger (52 years vs 66 years, p < 0.001) (Table 1). The average age of all patients was 60 ± 1.79 years old. 19 of 37 (51.3%) non-survivors had a past medical history of CAD. This was the only past medical history analyzed that was found to be significantly more prevalent in non-survivors than survivors (p = 0.037). Overall, our patient’s mean preoperative ejection fraction (EF) was 42%, this was not significantly different between survivors and non-survivors (p = 0.30).
22 of 60 (36.6%) cases were elective, 10 of 60 (16.6%) cases were emergent, and 28 of 60 (45%) cases were urgent (Table 4). There was no statistical difference between survivors and non-survivors based on operation classification (p > 0.05). In addition, ECMO cardiopulmonary resuscitation was initiated either in the operative theater or post-operatively in the ICU. ECMO cardiopulmonary resuscitation (eCPR) had a high incidence of mortality. 12 of 15 (80%) ECMO patients who had eCPR did not survive (table 3).
Table 4: Operation Classification
Operation Classification
|
Non-Survivors
(N total=37)
|
Survivors
(N total=23)
|
p
|
Elective
|
16
|
6
|
0.27
|
Emergent
|
7
|
3
|
0.73
|
Urgent
|
14
|
14
|
0.19
|
12 of 60 (20%) operative cases were isolated CABGs. Non-survivors (n = 10) had a mean of 2.86 vessel disease repaired whereas survivors (n = 2) had a mean of 3.75 vessel disease repaired. 17 of 60 (28.3%) patients underwent isolated valve repair. 6 of 60 (10%) patients underwent CABG and valve repair. 7 of 60 (11.7%) patients underwent aortic root repair. 4 of 60 (6.6%) patients had a LVAD placement. 2 of 60 (3.3%) patients underwent descending aortic repair. 8 of 60 (13.3%) patients underwent less commonly performed open heart procedures. 4 of 60 (6.6%) patients underwent OHT as their primary surgery (Table 5).
Table 5: Primary Surgery
Primary Surgery
|
Non-Survivors
(N total=37)
|
Survivors
(N total=23)
|
p
|
CABG
|
10
|
2
|
0.16
|
Valve Repair
|
10
|
7
|
0.77
|
CABG + Valve Repair
|
4
|
2
|
1.00
|
OHT
|
2
|
2
|
0.04
|
Aortic Root repair
|
5
|
2
|
0.69
|
LVAD placement
|
3
|
1
|
1.00
|
Descending Aortic Repair
|
0
|
2
|
0.14
|
Less commonly performed procedures
|
2
|
6
|
0.04
|
Legend: CABG: coronary artery bypass surgery
OHT: open heart surgery
LVAD: left ventricular assist device
However, in total 8 of 60 (13.3%) patients underwent OHT. 4 patients had OHT as their primary procedure and required ECMO to be brought out of the OR. 2 of the patients who had OHT performed as a primary procedure did not survive. Primary OHT was the only heart surgical procedure found to be significantly different between survivors and non-survivors (p = 0.04). 4 patients underwent OHT after being placed on ECMO as a salvage for their original cardiac surgical procedure. These 4 patients already had a primary open-heart surgery and OHT was attempted as a salvage procedure.
ECMO Secondary Outcomes and Adverse Events
19 of 37 non-survivors (51.3%) had a bleeding event while on ECMO. 5 of these 19 patients needed re-operation of their chest. 8 of 23 (34.7%) survivors had a bleeding event on ECMO. 2 of these 8 patients needed re-operation of their chest for bleeding. This was not significantly different between survivors and non-survivors, but is trending towards increased bleeding events in non-survivors (p = 0.28). Survivors needed a mean 13 units of blood, while non-survivors needed a mean of 25 units of blood, this was found to be significantly different between survivors and non-survivors (p = 0.02).
14 of 37 (37.8%) non-survivors required re-operation, which was significantly more than survivors (p = 0.04). 3 of 23 (13.0%) survivors required re-operation, 2 for bleeding and 1 for sternal wound dehiscence. 20 (54.0%) non-survivors and 5 (21.7%) survivors developed renal failure requiring renal replacement therapy without significant difference between these groups (p = 0.16). 18 (48%) non-survivors and 13 (56.5%) survivors developed sepsis, again, not statistically different (p = 0.6). 8 (21.6%) non-survivors and 1 (4.34%) survivor developed intracerebral hemorrhage/anoxic brain injury which is not significantly different (p = 0.13). 1 (2.7%) non-survivor developed and 2 (8.6%) survivors developed DVT/PE and was not significantly different (p = 0.56). 4 Patients (3 survivors), had clotting in their ECMO circuit, of these 2 patients were not anticoagulated with heparin and occurred at a mean of 10 days. Of note, one patient had thrombosis of the circuit in the OR and did not survive.