Extracorporeal cardiopulmonary resuscitation for adult patients who underwent post-cardiac surgery

The objective of the present study was to examine the clinical outcomes of ECPR in
adult patients with post-cardiotomy refractory CA. Results showed that among 24 adult
patients who received ECPR support for post-cardiotomy refractory CA, the mean ECMO
duration was 115.23 ± 70.17 h. The cardiac surgery procedures included coronary artery
bypass grafting (83.3 %), valvular surgery alone (8.3 %), and correction of congenital
heart defects (8.3 %). Twenty-one patients received ECPR after intra-aortic balloon
pump (IABP) and three patients received ECPR directly. The main cause of mortality
was multiple system organ failure (50.0 %). Approximately one-half of non-survivors
had severe neurologic impairments. Among 16 patients who were weaned from ECMO, eight
patients were alive at discharge.

ECPR provides a period of stability for the resolution of the underlying problems
that led to refractory CA in the first place 20]. Because of the cost, complexity of the technique, and required resources, ECPR is
not offered in all centers. However, ECPR is recommended for CA that is refractory
to initial resuscitation attempts if the condition leading to CA is reversible or
amenable to heart transplantation, if excellent conventional CPR has been performed
after no more than a few minutes of CA, and if the institution is able to rapidly
perform ECMO 21].

In the present study, CABG (83.3 %) was the most common surgical procedure that was
performed in patients who developed CA and required ECPR, which is in agreement with
a previous report 22]. It is unclear whether or not patients with coronary artery diseases or other cardiac
diseases are more sensitive to reperfusion injury of ischemic tissue, and whether
or not they are more susceptible to the possibility of myocardial injury following
ECPR 17]. Further studies are necessary to assess this point.

In the study by Lan et al. 22], the survival rate was 30.1 %, while the study by Flecher et al. 23] reported survival of 41–45 %. According to the Extracorporeal Life Support Organization
(ELSO) registry, the survival rate of adult patients receiving ECPR for CA was 28 %
between 1990 and 2012 24]. Although the survival rate in the present study was higher, it was comparable to
previous studies 9], 25]. However, the ELSO registry includes all patients receiving ECPR, while the present
study included patients who underwent cardiac surgery only. Another study in a population
of patients that was similar to the present study showed a survival of only 15 % 26]. As in the study by Lan et al. 22], gender did not affect survival at discharge.

In the present study, the duration of CPR and ECMO were also similar to those of Huang
et al. 19], and did not differ significantly between survivors and non-survivors. In our hospital,
the ECMO preparation room is next to the ICU and operating room; therefore, ECMO preparation
and initiation are very timely if CA occurs. Nine patients (37.5 %) suffered from
CA at the end of the surgery, and there was no need to move them before initiating
ECPR. Fourteen patients (58.3 %) suffered from CA in the ICU. In the present study,
set up time for ECPR (from notification of the ECMO team to running the ECMO pump)
was approximately 30 min. According to recent reports on CPR, the sooner ECPR is initiated,
the earlier systemic perfusion is improved, and the higher the survival rate 19], 27]. In the present study, there was a trend for higher mortality rates with increasing
CPR duration.

An IABP is the first option due to its relative non-invasiveness and low cost compared
with ECMO. In contrast, ECMO is the better choice for CA not amenable to IABP support
alone. Twenty-one patients (87.5 %) were New York Heart Association (NYHA) class III
or IV prior to surgery, and they had been using a preoperative or intraoperative IABP.
Refractory CA eventually occurred in this population after surgery because of the
inefficacy of IABP. For such patients, ECMO alone or in combination with IABP might
be used as soon as possible, but further studies are necessary to evaluate this approach.

According to several published studies, sepsis with MSOF has been associated with
poor outcomes 22]. However, there was no difference in the frequency of infections in the present study.
All patients of the non-survivor group with bacterial infections eventually developed
MSOF. Control of infections is still a major challenge in the ICU. In the present
study, MSOF was the primary cause of death. Patients who do not receive chest compressions
usually undergo a medical resuscitation using potent drugs that maintain the cardiopulmonary
function at the expense of other organ systems such as the kidneys 28]. In the present study, survivors at discharge had better creatinine and peak BUN
levels than non-survivors, and a larger proportion of non-survivors were undergoing
hemodialysis. As in the study by Grist et al. 20], patients sustained severe kidney damage with a dismal outcome, despite hemodialysis,
and still lacked adequate renal perfusion after ECMO.

A previous study reported that age 60 years, requirement of postoperative VA hemofiltration,
peak TBIL 102.6 µmol/L, and a need for ECPR were independent risk factors for in-hospital
mortality 29]. Another study reported that patients aged 65 years, pH 7.0, lactates 12 mmol/L,
creatinine 200 µmol/L, or receiving ECMO under advanced life support had a bad prognosis
23]. However, these factors could not be validated in the present study, mostly because
of the small sample size. Indeed, as a retrospective, non-randomized, observational
study, the present study had a number of limitations. Although this study collected
the neurological outcome data from all patients, detailed neurologic examinations
and neurodevelopmental evaluations were not recorded, as was the case in other series
19], 20], 22]. Many variables only showed a trend toward a difference, maybe due to the small sample
size, which also prevented subgroup analyses. A larger multicenter randomized study
is required to correctly assess the benefits of ECPR in patients with refractory CA
after cardiac surgery. In addition, the etiologies of CA after cardiac surgery were
not collected in the present study.

Similar to Kelly et al. 15], we hypothesize that early ECPR and effective care are necessary to the effectiveness
of ECMO for refractory CA after cardiac surgery. Given that medical and surgical complications
may occur during any phase of care, we emphasize the importance of multidisciplinary
collaboration between professionals involved in the care of these patients 30]. However, a recent meta-analysis reported that significant morbidities were associated
with ECMO, and that its use should be carefully considered based on the risk–benefit
ratio 31].