Management and Outcome of Cardiac and Endovascular Cystic Echinococcosis
et al. (2012) Management and Outcome of Cardiac and Endovascular
Cystic Echinococcosis. PLoS Negl Trop Dis 6(1): e1437. doi:10.1371/journal.pntd.0001437
Management and Outcome of Cardiac and Endovascular Cystic Echinococcosis
Marta Daz-Mene ndez 0 1
Jose Antonio Pe rez-Molina 0 1
Francesca Florence Norman 0 1
Ana Pe rez-Ayala 0 1
Hector H. Garcia, Universidad Peruana Cayetano Heredia, Peru
0 Tropical Medicine and Clinical Parasitology, Infectious Diseases Department, Ramo n y Cajal Hospital, Instituto Ramo n y Cajal de Investigacio n Sanitaria (IRYCIS) , Madrid , Spain
1 Begon a Monge-Maillo , Pilar Zamarro n Fuertes, Rogelio Lo pez-Ve lez
Background: Cystic echinococcosis (CE) can affect the heart and the vena cava but few cases are reported. Methods: A retrospective case series of 11 patients with cardiac and/or endovascular CE, followed-up over a period of 15 years (1995-2009) is reported. Results: Main clinical manifestations included thoracic pain or dyspnea, although 2 patients were asymptomatic. Cysts were located mostly in the right atrium and inferior vena cava. Nine patients were previously diagnosed with disseminated CE. Echocardiography was the diagnostic method of choice, although serology, electrocardiogram, chest X-ray, computed tomography/magnetic resonance imaging and histology aided with diagnosis and follow-up. Nine patients underwent cardiac surgery and nine received long-term antiparasitic treatment for a median duration of 25 months (range 4-93 months). One patient died intra-operatively due to cyst rupture and endovascular dissemination. Two patients died 10 and 14 years after diagnosis, due to pulmonary embolism (PE) and cardiac failure, respectively. One patient was lost to follow-up. Patients who had cardiac involvement exclusively did not have complications after surgery and were considered cured. There was only one recurrence requiring a second operation. Patients with vena cava involvement developed PEs and presented multiple complications. Conclusions: Cardiovascular CE is associated with a high risk of potentially lethal complications. Clinical manifestations and complications vary according to cyst location. Isolated cardiac CE may be cured after surgery, while endovascular extracardiac involvement is associated with severe chronic complications. CE should be included in the differential diagnosis of cardiovascular disease in patients from endemic areas.
Competing Interests: The authors have declared that no competing interests exist.
Cystic echinococcosis (CE) is a zoonotic infection caused by the
larval stage of the tapeworm Echinococcus granulosus. This parasitic
disease occurs in humans (who act as intermediate hosts) when the
ova of E. granulosus from canine (definitive host) faeces are
accidentally swallowed. After ingestion, the parasite crosses the
duodenal wall and spreads via the portal and systemic circulation
to the liver, lungs and other organs. CE is endemic in Europe,
including the Mediterranean area and the Balcanic nations, North
and East Africa, India, China, Indonesia and the Southern Cone
of the Americas .
Hydatid cysts may be found at almost any site of the body, but
the liver (6070%) and lungs (1015%) are most frequently
affected . The heart is reported to be involved in less than 2%
of cases . Endovascular extracardiac CE is very rare, only a
handful of cases have been reported and these are thought to be
secondary to the rupture of the primary germinative membrane of
cysts located at other sites, mostly in the heart or vena cava
(including the intrahepatic portion of the cava), with consequent
embolization to the pulmonary or systemic circulation .
We describe 11 patients who were diagnosed and treated for
cardiac and endovascular CE. Cases from the literature were also
reviewed and recommendations for the management of patients
This was a retrospective analysis, the data were analyzed
anonymously and written informed consent was not obtained for
individual participants. The database from which patients
information was obtained has been approved by the Ramo n y
Cajal Hospitals Ethics Committee (Comite Etico de Investigacio n
Clnica, CEIC, Hospital Ramo n y Cajal) and is used in
accordance with the current laws in Spain (Ley Organica de
Proteccio n de Datos de Caracter Personal 15/1999) which
guarantee patient confidentiality.
Cardiac and vascular involvement are infrequent in
classical cystic echinococcosis (CE), but when they occur
they tend to present earlier and are associated with
complications that may be life threatening. Cardiovascular
CE usually requires complex surgery, so in low-income
countries the outcome is frequently fatal. This case series
describes the characteristics of cardiovascular CE in
patients diagnosed and treated at a Tropical Medicine &
Clinical Parasitology Center in Spain. A retrospective case
series of 11 patients with cardiac and/or endovascular CE,
followed-up over a period of 15 years (19952009) is
reported. The main clinical manifestations included
thoracic pain or dyspnea, although 2 patients were
asymptomatic. The clinical picture and complications vary
according to cyst location. Isolated cardiac CE may be
cured after surgery, while endovascular extracardiac
involvement is associated with severe chronic
complications. CE should be included in the differential diagnosis of
cardiovascular disease in patients from endemic areas. CE
is a neglected disease and further studies are necessary in
order to make more definite management
recommendations for this rare and severe form of the disease. The
authors propose a general approach based on cyst
location: exclusively cardiac, endovascular or both.
A retrospective study was performed involving patients with
cardiac and endovascular extracardiac CE, diagnosed and treated
over a period of 15 years (January 1995 through December 2009)
at the Tropical Medicine & Clinical Parasitology Center of the
Ramo n y Cajal Hospital in Madrid, Spain.
CE and its location was diagnosed according to
echocardiography, computed tomography scan (CT)/magnetic resonance
imaging (MRI), electrocardiography, chest X-ray, histological
criteria and serology (IHA and ELISA techniques) . Data
regarding gender, age, area of origin, clinical presentation,
diagnostic methods, surgical and medical management and
outcome were analyzed using descriptive statistics.
Also, a systematic search of MEDLINE and EMBASE was
carried out (for all published articles until June 2011) using the
following terms: cardiac echinococcosis, cardiac cystic
echinococcosis, cardiac hydatidosis, cardiac hydatid cyst, cardiac hydatid
disease, pulmonary cystic embolism, pulmonary hydatid
embolism, caval hydatidosis, cava vein hydatidosis, cava vein
echinococcosis, endovascular hydatid disease, endovascular hydatidosis,
endovascular echinococcosis. No language, age or gender
restrictions were used. Individual articles were included.
Eleven patients with cardiac and/or endovascular CE were
evaluated. All of them were Spanish except one, who was an
immigrant Bulgarian child (patient 5). Seven patients lived in rural
areas, while the rest came from urban areas, although they had
lived intermittently in Spanish rural towns. Demographic
characteristics, clinical presentation, CE location (both
cardiovascular and extra-cardiovascular), medical and surgical treatment
and outcome are summarized in Table 1.
The mean age was 49.4 years (sd620.4; range = 968 years,
median = 60 years) and four patients were female. Patients main
initial symptoms and signs indicative of cardiovascular disease
were chest pain in 7 cases, dyspnea in 4 cases, and haemoptysis in
2 cases. Two patients had no symptoms (diagnosis of
cardiovascular CE was made following investigations for other causes).
Regarding the cardiovascular examination, only one case (patient
6) had an aortic murmur (grade I/IV). Furthermore, one case
(patient 2) had three strokes, epilepsy and intermittent claudication
of the lower extremities (a brain CT showed no cerebral CE and
carotid ultrasound demonstrated advanced atherosclerosis).
Two cases (patients 3 and 5) showed primary and exclusive
cardiac involvement. In the remaining 9 cases (82%) there was
concomitant extravascular disease: lung involvement in 1 case
(patient 4), lung and liver involvement in 3 cases (patients 7 and 9),
and disseminated CE (intraabdominal, kidney, spleen, liver and
lungs) in 5 cases (patients 1, 2, 8, 10, 11).
Eosinophilia (.400cells/mm3) was present in 6 patients (55%).
Serological tests (haemagglutination inhibition and ELISA
techniques) were positive for all patients. Electrocardiogram was
abnormal in 3 cases: signs of atrial hypertrophy (patient 2), left
bundle branch block (patient #1) and right bundle branch block
(patient 6) were found. The latter two patients had an
interventricular septum cyst. An abnormal cardiac outline was
detected on chest X- ray in 2 cases (patients 2 & 5, both patients
had a pericardial cyst).
Two-dimensional echocardiography was diagnostic in all cases.
Cysts in a single location were found in 4 patients: 2 in the
interventricular septum (Figure 1), 1 in the right atrium and
another in the right ventricle. Cysts in $2 cardiovascular locations
were present in 7 patients (64%): 5 in the right atrium and vena
cava, for 1 patient in the left atrium and pericardium and for
another in the atrioventricular area and pericardium. CT and
MRI confirmed those findings and also detected a pulmonary
hydatid embolism in 5 cases (45%) (patients 7, 8, 9, 10, 11). Data
regarding pulmonary artery pressures were not available in most
Histology confirmed the diagnosis of CE in all of the cases
where surgical samples were sent for pathological assessment (9/9),
according to literature .
Management of CE was based on WHO guidelines , even
though there are no clear recommendations when the disease
affects the cardiovascular system. Our approach was as follows:
Nine patients underwent cardiovascular surgery to excise the
cysts. Patients 3 and 10 refused surgery, as both were
asymptomatic and aged $65 years. Cardiopulmonary by-pass
was instituted with bicaval cannulation. Standard myocardial
protection with cold cardioplegic cardiac arrest was achieved in all
cases. Surgical techniques used for cyst removal were radical
cystectomy (patients 1, 2, 4, 7, 8, 9, 11), and aspiration associated
with capitonnage (Patients 5, 6). In 6 cases, a larvicidal agent
(hypertonic saline and/or hydrogen peroxide) was instilled in the
area occupied by the cyst. A single intervention was sufficient
except in the case of the Bulgarian child (patient 5) with pericardial
CE who needed a second intervention (it is possible only partial
cystectomy was performed during the first surgery in Bulgaria).
Postoperative complications were documented in 2/9 patients:
patient 2 developed atrial fibrillation responsive to antiarrhythmic
drugs, and patient 9, who had extensive inferior vena cava
involvement and massive hydatid pulmonary embolism, died
during surgery secondary to intraoperative cyst rupture. Both the
massive antigenic stimuli and pulmonary emboli could be
responsible for the death of the patient.
Long-term antihelminthic therapy was prescribed in 9 patients
(81.8%). Patient 3 refused medical therapy as she was
asymptomatic and patient 9 died during surgery before starting treatment.
Drugs used were albendazole 15 mg/Kg/d and praziquantel
40 mg/Kg/d: all patients received albendazole and in 6 cases
(67%) this was combined with praziquantel. The mean duration of
treatment was 37 months, (Interquartile range 964.5 months;
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median 25 months, range 493 months). Three patients developed
side effects: 2 (patient 1, 5) had mild transaminase elevation and 1
(patient 11) had mild pancytopenia. All of these effects were
reversible after the temporal discontinuation of the drugs.
The patients were followed-up for a median period of 6 years
(range = 114 years). Different outcomes were observed depending
on cyst location. Of the two patients with cardiac involvement
alone, one (patient 5) remained asymptomatic and stable and the
other (patient 3) was lost after 1 year of follow-up. Of the 4 patients
with cardiac and disseminated CE (patients 1, 2, 4 and 6), 1
patient was lost to follow up after 3 years (patient 1); for patient 4
cardiac surgery was curative, and the calcified pulmonary cyst
remained the same size after 14 years of follow up (CT scan
performed annually), with no associated complications. Patient 2
underwent hepatic PAIR (puncture, aspiration, injection,
reaspiration) and remained stable, and patient 6 was stable for the 14
years following diagnosis, but later died due to cardiac failure not
related to CE. All 5 patients with cardiac, inferior vena cava and
disseminated CE (patients 711) developed a pulmonary embolism
as a complication (Figure 2). For 4 of the cases CE was the most
likely cause of the embolisms, but patient 10, who died 10 years
after diagnosis due to embolic pulmonary disease, had multiple
Mean age (years)/
Gender (% female)
Dali, 2000 
19881998 Tunisia 17
Akar, 2003 
Jerbi, 2004 
19912003 Tunisia 19
19701997 Tunisia 45
19832001 Tunisia 14
19852001 Tunisia 12
19992005 Morocco 10
Pericardium (1) Aorta (1)
45 surgery; 2 early
death, 2 recurrence
25 surgery; 1 early
death, 1 recurrence
15 surgery and
albendazole; 1 early
death, 4 recurrence
19 surgery and
13 surgery and
risk factors for emboli (bed rest, smoking and chronic venous
insufficiency) so the origin/cause of the embolus could not be
ascertained. The patient had received albendazole for 23 months
with unproven efficacy. Patient 9 died during surgery as
mentioned previously. Patient 7 needed multiple embolizations
and could have been considered a candidate for transplantation,
but previous thoracic surgery would have contraindicated
transplantation. Patients 8 and 11, who were heavy smokers,
had chronic respiratory insufficiency, diagnosed based on
spirometry results. Patient 11 also required cholecystectomy due
to CE-associated cholangitis.
Although after reviewing the literature we found more than 200
published cases of cardiac/endovascular CE these are not usually
grouped in large series, and are mainly single cases. Table 2
summarizes the case series with 10 or more patients with cardiac
CE which have been published in the last ten years .
Table 3 summarizes all reported cases with CE endovascular IVC
Cardiac and endovascular CE are rare and heterogeneous
diseases and therefore management is not standardized.
Information from the current series, together with that from other
previously published series, may assist in the approach to this
Given the slow growth of cysts and assuming exposure during
childhood/adolescence, classical CE tends to give symptoms and
signs between the third and fifth decade of life . Due to the
specific location of cardiac cysts in areas which may result in
functional impairment, such as the cardiac conduction system, and
because of the limited capacity for expansion (in contrast to organs
such as liver or lung), age of onset is younger than for classical CE,
with onset of symptoms between the 2nd and 4th decade. This
early onset is also seen at other locations, like the eye or the CNS,
where even small cysts can rapidly become symptomatic. Cardiac
CE rates documented in children under 20 years are around 20%
[9,31] similar to those found in our series: 2/11 cases (18%) were
,20 years of age (9 and 19 years, patients 5, 7).
Clinical manifestations depend on the location, number and size
of cysts . Most frequently CE presents with thoracic pain or
dyspnea, as observed in our series, but the clinical presentation of
cardiac CE may range from asymptomatic to life-threatening
events. Asymptomatic subjects represent 35% of cases and in
these cases cysts are not usually located in a critical anatomical site
. This may be compared with hepatic CE where up to 50% of
cases may be asymptomatic. In these cases, CE may be an
Reference and country
Age (years)/Gender CE location
Aikat, 1978 ; India
Landra,1984 ; India
Ambrosi, 1991 ; France
Caballero,1999 ; Spain
Sirmali, 2006 ; Turkey
Meekel,2007 ; USA
Agarwal,2009 ; India
Karunajeewa, 2001 ; Australia 65 y/M
IVC, RA, Liver and lung
Cystectomy/No medical treatment
Cystectomy and caval graft/ND
IVC, RA, Liver and lung
IVC, RA, Liver
Cystectomy/ALB pre surgery
IVC, RA, Liver and lung
IVC, Liver and lung.
Cystectomy and omentoplasty, cyst No recurrence (16 months follow
removal from pulmonary artery (second up)
operation)/ALB 12 w after surgery
Cystectomy and caval graft/ND
Died 6 days after surgery (liver
and renal failure)
Died in early postoperative
period due to IDC and
Note: ALB: Albendazole; CE: cystic echinococcosis; CT scan: computed tomography scan F: female; IVC: inferior vena cava; IDC: intravascular disseminated coagulation;
M: male; MRI: Magnetic Resonance Imaging ND: not defined; RA: right atrium; w: weeks.
*Only intraluminal invasion. Cases with vena cava compression and vena cava wall involvement are excluded.
incidental finding . It is possible that the number of
asymptomatic cases may be underestimated, as more cases with
identifiable symptoms may be diagnosed/reported, leading to
publication bias. In our series, 2/11 patients (18%) were
asymptomatic at the time of diagnosis (patients 3 and 10). Cardiac
CE may present with potentially life-threatening events such as
cardiac tamponade, heart failure, syncope, arrhythmias, valvular
stenosis or regurgitation, pulmonary hypertension, or peripheral
embolism [34,43]. Severe chronic pulmonary hypertension in the
setting of recurrent emboli from intrahepatic disease has been
reported, as well as acute embolic events resulting in death .
Unlike classic CE, in which reported mortality rates range
between 0.54%, in cardiac CE, mortality is 410%, usually
occurring in the postoperative period [22,44]. In this series the
recorded mortality rate was 27%, but this occurred shortly after
diagnosis in only 1 case (patient 9), while for the other two patients
(patients 6 and10) death occurred more than 10 years after
diagnosis of cardiac involvementand was associated in both with
disseminated CE. Cardiac CE usually occurs in the left ventricle or
in the interventricular septum. We found a higher prevalence of
disease in the right atrium (55%), whereas in the literature
reported rates for this location are of 47% [9,40]. This high
incidence is probably due to the high incidence of coexisting vena
cava involvement that was found in our series.
As with clinical manifestations, complications of cardiac CE also
vary according to location of cysts: those on the right side of the
heart may fragment and embolize to the lung, causing massive
haemoptysis (patient 7) or pulmonary hypertension. Those located
on the left side, can produce peripheral emboli [13,14,45,46]:
patient 2 was diagnosed with intermittent claudication and stroke,
initially attributed to atherosclerosis. Although this patient had
documented cardiovascular risk factors, CE could not be ruled out
as a cause, as the left atrium was also involved and disease at this site
could have been the source of embolisms. The occurrence of
pulmonary embolism in cardiac CE is around 68% . We have
recorded a higher incidence (45%), probably due to the high rates of
right atrium and inferior vena cava involvement found in our series.
Cardiac CE is commonly associated with CE disease in other
organs . In our series, 45.5% of patients had disseminated
disease. Clinical examination is usually unremarkable unless
cardiac CE alters valvular function (producing valvular failure or
stenosis) [9,45]. Patient 6 had a heart murmur on auscultation.
Even though valvular involvement was not demonstrated by
echocardiography, the intraseptal cyst (4,2 cm) protruding into the
left ventricle could explain the presence of the murmur.
Cardiac rhythm disturbances are due to involvement of the
cardiac conduction system [44,48]. Three of our patients had
ECG abnormalities: two of them had bundle branch block, due to
cardiac intraseptal involvement.
Even though serological tests may not be useful in cases of
extrahepatic involvement  all our patients had positive
serological tests (ELISA or HAI). Serology is usually strongly
positive in CE cases when there is systemic involvement .
An assessment of the heart and main vessels by
echocardiography may be recommended for all individuals diagnosed with
CE, even if they are asymptomatic. This technique has proven to
be highly sensitive in detecting cysts in the heart and surrounding
Both CT and MRI are useful additional imaging techniques to
confirm the diagnosis and detect complications (especially in the
case of hydatid pulmonary embolisms) .
A standardized therapeutic approach may not be possible due
to the heterogeneity of cardiovascular CE, and may require the
combination of medical and surgical treatment. Benzimidazoles
(albendazole, in countries that can afford it, or mebendazole) with
or without praziquentel are the basis of pharmacological therapy
[53,17], although the dose and duration of treatment have not
been clearly established .
Based on this series and published data, the following
therapeutic approach may be recommended:
1. If there is cardiac involvement exclusively, surgery may be curative . The technique requires cardiopulmonary bypass and clamping of surrounding vessels to prevent spillage. Instillation of scolicidal substances could be beneficial [8,30].
In these cases, mortality is mainly related to complications
arising from the surgical procedure such as ventricular rupture,
fatal arrhythmias,embolisms or massive cyst rupture with
anaphylaxis (as in patient 9) . The mortality rate may be
higher in centres lacking in expertise or within adequate
infrastructure to deal with complex cases. The treatment of
cardiac CE in low-income countries is therefore very limited
and the prognosis is poor. Surgery is often combined with a
short course of pre-intervention prophylaxis  with
benzimidazoles in order to prevent the spread of the cyst but
currently definitive data from clinical trials are lacking . Its
use before surgery may even be contraindicated because the
pericyst membrane may become more friable and may rupture
during surgical manipulation.
2. If there is cardiac involvement and disseminated CE: cardiac
surgery may also be required, even though the prognosis is
worse due to possible complications at different locations (cyst
rupture, fistulae, cholangitis, etc.). Thus, the need for
percutaneous treatment (PAIR or PEvac), surgery or other
techniques (embolization, etc.) may be conditioned by the
possibility of such complications. In this circumstance, the use
of albendazole, with or without praziquantel, has shown to be
beneficial. Given the poor correlation between serum
concentrations of albendazole and parasite viability, the effectiveness
of benzimidazoles appears to be more dependant on the
duration of treatment than drug blood levels . Therefore,
these patients will require long-term treatment to prevent
relapses and to slow the growth of existing cysts. For patients 7
and 8 endovascular cysts grew after stopping long-term
antiparasitic treatment (treatment discontinued for a mean of
12 months), Treatment was then reinitiated and maintained
indefinitely and they remained stable. In our series no relevant
side effects were observed despite prolonged treatment, which
is consistent with results published in the literature [58,59].
3. If there is associated vena cava involvement due to CE: it is
difficult to draw conclusions regarding management as few
cases are documented in the literature. For these patients early
and radical management of endovascular disease is proposed in
order to avoid associated complications (mainly hydatid
embolism). As far as possible, the cyst should be resected and
the affected vessel should be reconstructed . Since the
majority of pulmonary emboli come from liver cyst rupture
near the hepatic veins or inferior vena cava , the surgeon
should take particular care with vascular structures during
surgery of the cysts to prevent spread. If there is a potential risk
of vena cava invasion (hepatic cysts close to the vascular bed or
in the right atrium) close monitoring of the patient may be of
choice. In case of intra-hepatic vascular involvement where
there is risk of intra-hepatic inferior vena cava rupture
intraoperative caval-caval bypass should be recommended or
considered to avoid massive embolization during surgery. In
addition, patients should have a pre-operative echo and
evaluation of right sided pressures as they may require invasive
cardiac monitoring during surgery . Thus, the appearance
of lesions may be detected at an early stage, with early removal
and clamping of the vessel to prevent the spread of the disease.
If the risk of vena cava involvement is very high, surgery may
be performed directly on the lesion, although the indication for
surgery has not clearly been established in these cases.
Whateveroption is chosen, antihelminthic drugs should be
used to prevent recurrence.
4. If there is evidence of pulmonary embolism due to CE, surgery
will be complex at this location. In cases in which the embolus
is already established, early surgery at the source of the emboli
may be recommended, combined with indefinite medical
Although our case series is not large enough to give
recommendations regarding follow-up, we suggest indefinite antihelminthic
treatment with albendazole in disseminated CE and pulmonary
embolism due to CE, and repeated CT scan (preferably CT
angiography) in any case surgery cannnot be curative to evaluate
changes in the size of the cysts in the heart, vessels and lungs.
Cardiovascular involvement is a rare form of presentation of
CE. It presents earlier than classical CE and is associated with
complications that may be life threatening. Cardiovascular CE
usually requires complex surgery, so that in low-income countries,
the prognosis is frequently fatal. CE is a neglected disease and
further research is necessary in order to make more definite
management recommendations. More prospective studies with a
larger number of cases will be needed to define an ideal
therapeutic approach and experimental research is mandatory to
obtain more effective drugs for treating this devastating disease.
We would like to thank the members of the Radiology department of the
Hospital Ramon y Cajal for their assistance.
Conceived and designed the experiments: MD-M JAP-M RL-V.
Performed the experiments: MD-M JAP-M RL-V. Analyzed the data:
MD-M JAP-M RL-V. Contributed reagents/materials/analysis tools:
MD-M JAP-M RL-V. Wrote the paper: MD-M JAP-M FFN AP-A
BMM PZF RL-V.
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