H S Ashok Kumar

N Umadevi

S Anitha

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185 International Journal of Scientific Study | November 2015 | Vol 3 | Issue 8
Management of Acardiac Twins: Does Conservative 
Approach Deserves Consideration? A Case Report
H S Ashok Kumar1, S Anitha2, N Umadevi3
1Assistant Professor, Department of Obstetrics and Gynecology, KMCT Medical College, Kozhikode, Kerala, India, 2Senior Resident, 
Department of Obstetrics and Gynecology, Government Medical College, Kozhikode, Kerala, India, 3Professor, Department of Obstetrics and 
Gynecology, MES Medical College, Perinthalmanna, Malappuram, India
CASE REPORT
A 25-year-old G2P1L1 with previous cesarean section done 
referred to our tertiary care center at 10 weeks of  gestation 
as a case of  monochorionic and monoamniotic (MCMA) 
twins with single fetal demise. She had excellent dates. Her 
family history and past history were absolutely unremarkable 
for twins or perinatal issues. All routine investigations were 
done and found to be within normal limits. Since then the 
patient had regular antenatal check-ups from our institute. 
During routine antenatal care at 20 weeks of  gestation, 
the abdomen was enlarged to around 24 weeks. We got an 
ultrasound (USG) scan done. To our surprise, USG revealed a 
twin pregnancy with a single placental mass, and there was no 
dividing membrane (MCMA). There was appropriate for dates 
twin without any obvious anomalies, which was associated 
with an acardiac, acranial amorphous twin (Figure 1). At that 
time size of  the cardiac twin was almost same as the pump 
twin. But, pump twin showed no signs of  decompensation. 
We discussed in detail with parents about the condition, and 
we also counseled them about the risks and benefits of  the 
expectant management and surgical intervention.
Management and Outcome
Pregnancy was followed up carefully with serial USG 
studies, Doppler flow studies, non-stress test (NST), 
INTRODUCTION
Acardiac malformation also known as twin reversed arterial 
perfusion (TRAP) sequence, is a unique complication 
of  monochorionic pregnancies. It is characterized by 
paradoxical retrograde perfusion of  abnormal twin by 
structurally normal pump twin through a single artery-
artery anastomosis.1 It is a very rare condition. The 
reported incidence being 1 in 35,000 deliveries and 1 in 
100 monozygotic twins.
Optimal management of  acardiac twin pregnancies is 
controversial. The reported fetal/neonatal mortality of  
the pump twin is extremely high (50-60%). It is thought 
primarily to be due to increasing in cardiac demands of  the 
pump twin in an effort to perfuse its acardiac sibling. Data 
suggest 50% mortality rate in pump twin with expectant 
management.
Case Report
Abstract
Acardiac twinning, a rare congenital anomaly of monozygotic twin pregnancies, often leading to abnormal placental vascular 
anastomosis. This in turn results in twin reversed arterial perfusion (TRAP) with complex pathophysiology. Current information 
on early diagnosis and treatment for the salvation of the pump twin is based mainly on various individual case reports. Here, we 
report a case of monozygotic twin complicated with TRAP sequence, which was diagnosed early, managed conservatively and 
the outcome was excellent. With the availability of various sophisticated studies for antepartum fetal surveillance, outcomes in 
expectantly managed cases are getting better. So, in acardiac twins aggressive interventions should be used cautiously and 
should be reserved only for some really indicated cases.
Key words: Acardiac twin, Conservative management, Monochorionic twins, Twin pregnancy, Twin reversed arterial 
perfusion sequence
Access this article online
www.ijss-sn.com
Month of Submission : 09-2015 
Month of Peer Review : 10-2015 
Month of Acceptance : 11-2015 
Month of Publishing : 11-2015
Corresponding Author: Dr. H S Ashok Kumar, S/O H.V. Shadaksharappa, Sri Basaveshwara Nilaya, P.O Road, Hemavathi Nagara, 
Hassan - 573 201, Karnataka, India. Phone: +91-9645238934. E-mail: patel.ashok97@gmail.com
DOI: 10.17354/ijss/2015/537
Kumar, et al.: The Management of Acardiac Twins, Does Conservative Approach Deserves Consideration?
186International Journal of Scientific Study | November 2015 | Vol 3 | Issue 8
biophysical profile (BPP), and fetal echocardiography. 
USG with Doppler study was done once in 2 weeks. 
Echocardiography was done at 24, 28, and 32 weeks of  
gestation. We looked closely for the presence of  any signs 
of  decompensation like pericardial or pleural effusion, 
or ascites. Serial USG scan revealed that acardiac twin 
was constantly increasing in size. USG at 32 weeks of  
gestation showed the acardius which had increased in 
size relative to the pump twin, who had maintained an 
appropriate weight for gestational age with an estimated 
fetal weight of  1.960 kg. But, pump twin showed no signs 
of  decompensation. The patient was admitted at 30 weeks 
of  gestation. Alternate day NST was done, which was found 
to be reactive. Two doses of  betamethasone were given 
24 h apart for fetal lung maturity.
At 34 weeks of  gestation, the patient presented with 
preterm premature rupture of  membranes. Emergency 
lower segment Cesarean section was done. Pump twin 
weighed 1.9 kg with APGAR 1’9. Acardiac twin weighed 
2.9 kg, its head, and upper extremities were absent. It had 
well-developed lower limbs (Figure 2). Pump twin was 
apparently alright, and it showed no apparent anomalies 
(Figure 3). The baby was kept in NICU for 12 h for 
observation. As there were no signs of  failure, it was 
managed on mother side only.
Postnatally pump twin was healthy. Both mother and baby 
were discharged on day 6.
DISCUSSION
Acardiac twinning or TRAP sequence is a rare congenital 
anomaly of  monozygotic multiple pregnancy. This occurs 
secondary to abnormal placental anastomosis which is 
characterized by formation of  a malformed fetus with 
an absent or rudimentary heart (acardius) and other 
structures.1
The pathogenesis in TRAP sequence is, there will be a 
defect in embryogenesis in one of  the twin leads to failure 
of  cardiac development. The normal twin then perfuses the 
acardiac twin via placental artery-artery anastomoses.2 It 
should be noted that the cardiac anomaly is not secondary 
to anastomoses, but they are established as a result of  it.3,4
Within the placenta, which is singe and shared by both the 
twins, arterial perfusion pressure of  the donor twin exceeds 
that of  the acardiac twin who thus receives reverse blood 
flow of  deoxygenated arterial blood. This used blood 
reaches the recipient twin through its umbilical arteries, 
and it preferentially goes to iliac blood vessels. Thus, only 
the lower extremity is perfused and disrupted growth and 
development of  the upper extremity results as occurred 
in the present case.5
The main differential diagnosis of  acardiac twin is the 
intrauterine death of  one of  the monochorionic twin, which 
Figure 1: Ultrasound taken at 20 weeks of gestation showing 
pump twin and acardiac twin.
Figure 2: Acardiac twin
Figure 3: Pump twin
Kumar, et al.: The Management of Acardiac Twins, Does Conservative Approach Deserves Consideration?
187 International Journal of Scientific Study | November 2015 | Vol 3 | Issue 8
will be anomalous. (In the present case, it was misdiagnosed 
in 10 weeks USG as MCMA twin with single fetal demise). 
However, the continued growth of  the “presumed dead” 
twin on subsequent scans is often the first clue to the correct 
diagnosis. The color flow imaging plays a major role in 
establishing the diagnosis of  acardiac twin. This shows the 
presence of  blood flow within the abnormal fetus. This may 
be evident even during the first trimester.6
When blood flow pattern is examined in detail in these 
cases, it reveals a paradoxical direction of  arterial blood 
flow toward acardiac twin. Lately, three-dimensional USG 
has also been used for confirmation of  diagnosis and also 
to establish the extent of  fetal malformation.7
It is clear that TRAP sequence poses substantial risks for 
the pump twin. Ideally, a diagnostic test would allow us 
to distinguish between cases that can be safely managed 
expectantly and those that require intervention. USG with 
Doppler studies, BPP, NST, and fetal echocardiography 
play a significant role in deciding the course of  treatment.
Even though the pathophysiology of  acardiac twin has 
been clearly resolved and treatment by ablating this vascular 
connection has been proposed, the availability and difficulty 
of  this mode of  treatment and fetal death secondary to the 
treatment itself  have been clearly demonstrated. Invasive 
treatment should be restricted, only to those pregnancies 
which would benefit from prenatal intervention like 
those where the donor twin is at a significant risk of  
prematurity, cardiac failure or death and should be 
considered in presence of  poor prognostic factors such 
as polyhydramnios, ascites, large acardiac twin, and rapid 
growth or evidence of  substantial blood flow through the 
umbilical vessel supplying the acardiac twin.8
Sullivan et al. advocated expectant management in all cases 
complicated with TRAP sequence.9 90% survival in pump 
twin were reported in 10 pregnancies with an acardiac 
twin managed expectantly. They recommended expectant 
management with close fetal surveillance in all cases, and 
aggressive interventions should be used cautiously.
The best time to intervene and best mode of  intervention 
are not yet known. With an increase in antenatal diagnosis 
and with the availability of  various sophisticated studies 
for antepartum fetal surveillance, outcomes in expectantly 
managed cases are getting better, and they are better than 
reported.
In the presented case, even though pump twin weighed only 
3/4th the weight of  acardiac twin it showed no signs of  
decompensation. The outcome, in this case, was excellent.
CONCLUSION
The most appropriate interventions and management 
protocols for the various clinical presentations of  TRAP 
Sequence is as yet to be determined, and conservative 
non-intervention is often appropriate in some carefully 
selected cases. This case report demonstrates that in TRAP 
sequence, early diagnosis, close antenatal follow-up can 
prevent unnecessary interventions without compromising 
the outcome. Long-term follow-up data on surviving pump 
twin are lacking. It is anticipated that centers with active 
study protocols for these conditions will best serve patient 
care and clinical research needs.
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How to cite this article: Kumar HS, Anitha, Umadevi N. Management of Acardiac Twins: Does Conservative Approach Deserves 
Consideration? A Case Report. Int J Sci Stud 2015;3(8):185-187.
Source of Support: Nil, Conflict of Interest: None declared.


Management of Acardiac Twins: Does Conservative Approach Deserves Consideration? A Case Report CASE REPORT

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Management of Acardiac Twins: Does Conservative Approach Deserves Consideration? A Case Report CASE REPORT

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