A Dose-effect Relationship Study Of Oxytocin On Blood Supply Of Uterine Fibroids

Background:Uterine fibroids are the most common benign tumor of women duringchildbearing age.The incidence rate is as high as20%-40%.Due to themenstrual symptoms of anemia, pelvic compression and infertility, morethan50%of patients need treatment. Currently, many techniques are used intreating uterine fibroids. Including medication and surgery, they are themost commonly methods in clinical treatment. High-intensity focusedultrasound ablation as a non-invasive technology, has been widely used inthe treatment of uterine fibroids in recent years. It is not only to relieve thepatient’s symptoms, but also can retain the uterus. How to improvetherapeutic efficacy of ultrasound ablation in the treatment of uterinefibroids, has been the focus of many studies. It has been found that oxytocincan reduce the energy in which the treatment required; it also can shortenthe treatment time, thereby oxytocin can enhance the treatment efficiency ofultrasound ablation. The mechanism is unknown that oxytocin improve theefficiency of ultrasound ablation. Which is the most appropriate dose whenultrasound ablation treats uterine fibroids? Is it safety for the unconventional dose? Whether the oxytocin test can help screen patients with T2hyperintense fibroids or not? Those questions need to be solved.Objective:1. To explore the mechanism that oxytocin improve ultrasound ablationefficiency. To study the safety of unconventional dose and to choose themost appropriate dose.2. To explore the relationship between oxytocin test and T2hyperintensefibroids ultrasound ablation prognosis, to help clinicians better filter T2hyperintense fibroids patients.Materials and Methods:1Part one A Dose-effect Relationship Study of Oxytocin On Vessels of UterineFibroids1.1Subjects:From March2010to May2011,120patients withfibroids,by enhanced MRI diagnosed, were selected in this prospectivestudy. They were randomly divided into three groups: each group hasfourty patients. Patient age, myoma size and location, they have no groupdifferences.1.2Equipments: PHILIPS HD3color Doppler ultrasound equipment wasused, and ultrasound probe frequency was3.5MHz.1.3Methods: Two-dimensional ultrasound clearly showed the uterinefibroids lesions. Power Doppler overall and careful observed the peripheraland internal flow signals of fibroids, respectively to search the widest feeding artery of fibroids peripheral and internal, then measured thediameter. The blood flow parameters were measured by pulse Doppler,including PSV, Vmean, RI, and blood flow. Patients were infused oxytocin,adjusted the drip rate to30drops/min. Group A, group B, group C wereinfused oxytocin at0.12U/min,0.24U/min, and0.36U/min respectively.After twenty minutes, measured peripheral and internal arterial’s diameterand blood flow parameters under the same conditions. The parameters wereset to be consistent in the ultrasonic inspection process. Using electronicECG dynamic observed patient’s vital signs throughout the course of thestudy. Each patient, including systolic blood pressure, diastolic bloodpressure, the average arterial pressure and heart rate,was recorded beforeintravenous oxytocin. After intravenous oxytocin one minute、 ten minuteand twenty minute recorded again respectively. In the same time recordedthe response of the patients discomfort. Within follow-up three months tomonitor long-term adverse effects. Results data were analysised using SAS9.2software.2.Part two The oxytocin test predict T2hyperintense uterine fibroids onultrasound ablation results2.1Subjects: From March2010to May2011,90patients with T2hyperintense uterine fibroids, through enhanced MRI diagnosed, preparedto reaccepted ultrasound ablation in the First Affiliated Hospital ofChongqing Medical University. 2.2Equipments: Ultrasound machines used the PHILIPS HD3colorDoppler ultrasound, the probe frequency was3.5MHz; JC FocusedUltrasound Tumor Therapy System (Chongqing HIFU (HIFU) TechnologyCo., Ltd.); Magnetom the Symphony1.5T MR by Tim system (Siemens,Germany).2.3Methods:1) Color Doppler ultrasound measured the feeding arteries blood flow ofuterine fibroids, and then measured again after intravenous infusionoxytocin.Oxytocin dose used0.12U/min. The same method as1.3.2) In the sedation and analgesia conditions, uterine fibroids were fullablation by JC focused ultrasound tumor therapy system;3) The myoma ablation was evaluated through enhanced magneticresonance (MR) imaging.Results:1. The hemodynamic parameters of the peripheral internal artery offibroid changed obviously after intravenous infusion of oxytocin. Forexample, peak systolic velocity (PSV), mean blood flow velocity (Vmean),diameter, blood flow decreased, and the resistance index (RI) increased.Those differences were statistically significant (P <0.05). Comparedintravenous infusion oxytocin before with after, the patient’s vital signsincluding heart rate, systolic, diastolic, mean arterial pressure were notstatistically significant (P>0.05). No adverse events observed in all patients.2.Peak systolic velocity, mean blood flow velocity, diameter and bloodflow of the fibroids feeding arteries of patients in those three groupdecreased, but that of resistance index increased, which were statisticallysignificant in contrast to the before (P＜0.05). But there was no statisticallysignificant difference of arterial changes before and after the intravenousinfusion of oxytocin among the three groups (P＞0.05).3.In the trial of oxytocin, when the blood supply to the fibroids peripheralarterial reduced less than50%,about79%(11/14) patients with ablationwere ineffective,When the blood supply to the fibroids peripheral arterialreduced more than50%, about7%(5/73) patients with ablation resultswere ineffective，the difference had significant.(P＜0.05); when the bloodsupply to the fibroids internal arterial reduced less than75%,about23%(10/44)patients with ablation were ineffective, When the blood supplyto the fibroids internal arterial reduced more than75%,about13%(6/46)patients with ablation results were ineffective,there was no statisticallysignificant difference(P＞0.05).Conclusions:1. Oxytocin can be safely and effectively reduce the blood supply of thefibroids,0.12U/min continuous infusion may be the most appropriatedose in the treatment of ultrasound ablation on uterine fibroids.2. Oxytocin test as an auxiliary indicator for screening patients with T2 hyperintense fibroids, has good clinical value.