Objective
The objective of the study was to assess the efficacy of uterine arteries embolization (UAE) for the treatment of cesarean scar pregnancies (CSP).
Study Design
Forty-six women with CSP were identified between March 2008 and March 2010. All of the patients underwent UAE combined with local methotrexate.
Results
Forty-five patients were successfully treated. One patient had an emergency hysterectomy after 20 days because of massive vaginal hemorrhage. The mean time until normalization of serum β-human chorionic gonadotrophin was 37.7 days, and the mean time until CSP mass disappearance was 33.3 days. The mean hospitalization time was 10.5 days. The complications were mainly fever and pain, which were alleviated with symptomatic treatment. All 45 patients had recovered their normal menstruation at follow-up.
Conclusion
Bilateral uterine artery chemoembolization with methotrexate appears to be a safe and effective treatment for CSP and causes less morbidity than current approaches.
Cesarean scar pregnancy (CSP) is a novel and life-threatening form of abnormal implantation of a gestational sac within the myometrium and the fibrous tissue of a previous cesarean scar. It has recently been found to be more common than was previously thought, and its estimated incidence ranges from 1 per 1800 to 1 per 2216 pregnancies, with a rate of 6.1% of all ectopic pregnancies with a history of at least 1 cesarean section. It is considered to be a long-term complication of cesarean section (CS), and its prevalence is currently increasing with the rising CS rate in China. Early and accurate diagnosis by improved ultrasound imaging and greater clinician awareness may be contributing to this rise.
CSP can lead to life-threatening hemorrhage during pregnancy or curettage and even to uterine rupture, disseminated intravascular coagulation, or death. Early and accurate diagnosis is important for effective treatment to avoid these potentially catastrophic consequences. Ultrasound was the first widely used method of diagnosing CSP. Recently improved ultrasound imaging has enabled correct early detection of such pregnancies with a sensitivity of 84.6%. However, it is difficult to distinguish a CSP from spontaneous miscarriage in progress or a cervicoisthmic pregnancy. Senior ultrasound practitioners may be more experienced in determining the details of the location, size, age, and viability of the gestation sac and may thus be better able to make a correct diagnosis, which is critical for timely effective management.
The aim in the management of CSP should be the prevention of massive hemorrhage and conservation of the uterus for further fecundity, health, and quality of life. Traditional management for CSP includes hysterectomy, local resection of the gestational mass within the previous cesarean scar, dilation and curettage, and systemic or local administration of drugs such as the metabolism inhibitor methotrexate (MTX). So far, although various interventions have been proposed, there has been no consensus on the optimal therapeutic protocol for CSP. MTX, used as a conservative treatment, was reported to have a high risk of failure and side effects, which necessitated treatment or even emergency hysterectomy.
Uterine artery embolization (UAE; blocking of the arteries using gelatin beads or other material) has been increasingly used before uterine surgery to prevent excessive bleeding in uterine myomas, cervical pregnancies, or postpartum hemorrhage or during chemotherapy to prevent uncontrollable bleeding in malignancies. Along with chemoembolization (a combination of embolization and local delivery of chemotherapy) being proved to be an effective anticancer treatment in clinical practice, bilateral uterine arterial chemoembolization has recently been tried out for CSP management.
In the procedure of bilateral uterine arterial chemoembolization, MTX is administered directly into the gestational foci through bilateral uterine arteries, which are its feeding blood supply, with subsequent blockage of the feeding vessel by occlusive agents that are injected through the delivery catheter. Because this involves both chemotherapy and tissue ischemia, it permits a higher concentration of MTX to target the gestational foci for a longer period of time and thus produces more effective embryocide, with much less systemic toxic effects, than embolization alone. To date, only a few reports that describe uterine artery chemoembolization with MTX for CSP treatment are available.
We retrospectively reviewed our management with bilateral uterine arterial chemoembolization with MTX of 46 cases of CSP over a 2 year period and analyzed complications and quality of life after treatment.
Materials and Methods
The research protocol was approved by the institutional review board of West China Second University Hospital, Sichuan University. Informed consent was obtained from all patients, and all available information on the treatments was presented to the patients, including the risks and benefits of the therapy, potential complications, and alternatives.
Between March 2008 and March 2010, 46 patients were diagnosed with CSP in our hospital. We reviewed the clinic records of all these patients, including patient age, gravidity and parity, clinical presentation, weeks of gestation, the time interval between the last cesarean section and cesarean scar pregnancy, clinical findings, results of ultrasound imaging examinations, therapeutic procedures, blood loss, and findings at follow-up.
In all patients, the gestational age was estimated according to the last menstrual period and ultrasonographic examinations, and serum β-human chorionic gonadotrophin (hCG) concentration was determined before treatment. The diagnoses of CSP were based on symptoms, clinical manifestations, history of prior cesarean section, serum β-hCG concentration, and special presentation on transvaginal ultrasonography.
The criteria of ultrasound diagnosis include the following: (1) an empty uterine cavity and cervical canal; (2) a gestational sac located at the anterior wall of the isthmic portion, separated from the endometrial cavity or fallopian tube; (3) a gestational sac embedded within the myometrium and the fibrous tissue of the cesarean section scar at the lower uterine segment, with an absence of defect in the myometrium between the bladder and the sac; and (4) and a high-velocity–low-impedance vascular flow surrounding the gestation sac. All 46 cases matched these criteria ( Figure 1 ).
The UAE procedure was performed by experienced radiologists. After local anesthesia, catheterization was carried out via the right femoral artery with a 5F-Yashiro catheter (Terumo, Tokyo, Japan) that was advanced into the uterine arteries on both sides; digital subtraction arteriography (AXIOM-Artis-FA; Siemens AG, Munich, Germany) was then performed to confirm that catheters were correctly inserted, and 25 mg of MTX was injected bilaterally; and finally both uterine arteries were embolized with gelatin sponge particles (0.5-1.0 mm). Subsequently, postembolization angiography was performed to validate that the vascularity of the gestational sac was completely obstructed ( Figure 2 ).
Twenty-four to 72 hours later, the patients were carefully examined using transvaginal ultrasound, and their serum β-hCG levels were assessed. In patients with persistent vaginal bleeding and/or a persistent gestational mass larger than 5 cm, suction curettage was performed under transabdominal ultrasound guidance after ultrasonic confirmation of the absence of blood flow to the CSP region to remove the retained products of conception and blood clot. If massive hemorrhage occurred during investigation or curettage, an emergency hysterectomy or local CSP resection was carried out.
Patients were hospitalized during treatment. Serum β-hCG levels, blood loss, adverse effects (including fever, nausea and vomiting, abdominal or pelvic pain, and abnormal liver or renal function), and length of hospital stay were recorded and summarized. Serum β-hCG levels were determined before the intervention, on day 1 after therapy, every 3 days until discharged from the hospital, and then every week until recovery to normality. At the same time, the sizes of the retained gestational products were measured by ultrasound and clinical status (bleeding pattern and resumption of menses) were assessed.
Follow-up was arranged until the serum β-hCG concentration dropped to normal and pregnancy remnants could not be detected through ultrasound. Women who had massive, active vaginal bleeding and stable serum β-hCG concentration after UAE were diagnosed as having their treatment failed and that required repeat embolization or partial/subtotal hysterectomy.
Successful UAE treatment was defined as a complete recovery without severe adverse effects or complications and without a need for repeat embolization or hysterectomy.
All data are expressed as mean ± SD. Statistical analysis was performed using the Student t test and a χ 2 test by the SPSS 19.0 statistical package (SPSS Inc, Chicago, IL).
Results
Forty-six cases of CSP were diagnosed over a 2 year period. The average age of the 46 patients was 32.7 ± 6.0 (21-44) years. The average gravidity was 5.0 ± 1.6 (2-8) and the average parity was 1.09 ± 0.28 (1-3). Four women had undergone 2 previous cesarean deliveries. The average interval from the last cesarean section was 63.5 ± 8.2 (4-252) months. The average gestational age at presentation was 55.5 ± 2.4 (37-97) days ( Table ).
| Characteristic | Mean ± SD (range) |
|---|---|
| Mean age, y | 32.7 ± 6.0 (21–44) |
| Previous pregnancies, n | 5.0 ± 1.6 (2–8) |
| 1 | 42 |
| 2 | 4 |
| Time from the last CS, mo | 63.5 ± 8.2 (4–252) |
| Gestational age, d | 55.5 ± 2.4 (37–97) |
| Time for serum β-hCG normalization, d | 37.7 ± 4.8 (7–150) |
| Time for CSP mass disappearance, d | 33.3 ± 4.3 (5–60) |
| Hospitalization, d | 10.5 ± 1.0 (4–35) |
| Successful cases, n (%) | 45 (97.8) |
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