Is maternal serum creatine kinase actually a marker for early diagnosis of ectopic pregnancy?

Using dynein heavy chain 5 and creatine kinase levels in cervical fluid and blood for early diagnosing of ectopic pregnancy

AIM

Ectopic pregnancy is a life-threatening problem in reproductive ages. Diagnosing ectopic pregnancy in the early period provides to reducing mortality and morbidity and gives an opportunity for medical treatment to preserve fallopian tubes. Evaluation of cervical fluid for determining ectopic pregnancy with new promising markers provided different aspects for diagnosing ectopic pregnancy in the present study.

METHODS

In this prospective clinical study, ectopic pregnant patients as ectopic pregnancy group (n = 46), intrauterine pregnant patients as intrauterine pregnancy group (n = 29) and not-pregnant patients as nonpregnancy group (n = 10) participated to study. Cervical fluid samples were collected with using merocel sponge. In addition, serum samples were obtained from patients. Dynein heavy chain 5 (DNAH5) and creatine kinase (CK) levels were determined by enzyme-linked immunosorbent assay kits in samples.

RESULTS

Reduced cervical fluid DNAH5 levels was diagnosed in ectopic pregnancy group compared to intrauterine pregnancy group (median 3.42 ng/mL; 25-75% percentile 0-9.56 ng/mL vs median 6.14 ng/mL; 1.40-8.31 ng/mL; P < 0.001). On the other hand, DNAH5 protein was not detected in nonpregnant patients' samples. In addition, statistical significant increased cervical fluid CK levels were diagnosed in ectopic pregnancy group compared to intrauterine pregnancy group (median 4477.61 IU/L; 0-64 925.37 IU/L vs 0 IU/L; 0-6832.30 IU/L; P = 0.006).

CONCLUSION

Measuring of CK and DNAH5 in cervical fluid could be promising markers for early diagnosing of ectopic pregnancy. Decreased DNAH5 levels in cervical fluid might be result from abnormal cilia function in ectopic pregnant patients. ClinicalTrials.gov ID. NCT02995356.

Molecular diagnostics and therapeutics for ectopic pregnancy

Ectopic pregnancies are a serious gynaecological emergency that can be fatal. As such, prompt diagnosis and safe timely treatment is essential. Here, we review the literature on the development of molecularly targeted diagnostics and therapeutics for ectopic pregnancy. A blood-based biomarker that accurately identifies an ectopic pregnancy could be used to offer early diagnostic certainty in cases where ultrasound cannot determine the location of the embryo ('a pregnancy of unknown location'). Molecules examined so far can be broadly grouped into biological themes of relevance to reproduction: (i) Fallopian tube (dys)function, (ii) embryo/trophoblast growth, (iii) corpus luteum function, (iv) inflammation, (v) uterine function and (vi) angiogenesis. While a sensitive and specific biomarker for ectopic pregnancy has yet to be identified, it is possible that improvements in platform technologies or a multi-modal biomarker approach may yield an accurate diagnostic biomarker test. Furthermore, with the advent of better imaging technology, the need for a blood-based biomarker test may be superseded by improvements in ultrasound or magnetic resonance imaging technology. There have been some recent preclinical studies describing molecularly targeted therapeutic approaches for ectopic pregnancy. Notably, bench-to-bedside studies have examined the use of combination gefitinib (orally available epidermal growth factor receptor inhibitor) and methotrexate. Preclinical studies suggest that combination gefitinib and methotrexate is highly effective in inducing placental cell death, and is significantly more effective than methotrexate alone. In early human trials, encouraging preliminary efficacy data have shown that combination gefitinib and methotrexate can rapidly resolve tubal ectopic pregnancies, and large extra-tubal ectopic pregnancies. If a large clinical randomized controlled trial confirms these findings, combination gefitinib and methotrexate could become a new medical treatment option for ectopic pregnancy.

Biomarkers for ectopic pregnancy and pregnancy of unknown location

Early pregnancy failure is the most common complication of pregnancy, and 1% to 2% of all pregnancies will be ectopic. As one of the leading causes of maternal morbidity and mortality, diagnosing ectopic pregnancy and determining the fate of a pregnancy of unknown location are of great clinical concern. Several serum and plasma biomarkers for ectopic pregnancy have been investigated independently and in combination. The following is a review of the state of biomarker discovery and development for ectopic pregnancy and pregnancy of unknown location.

Serum biomarkers of tubal ectopic pregnancy: current candidates and future possibilities

Ectopic pregnancy remains a considerable cause of maternal morbidity and mortality worldwide. Currently, it is diagnosed using a combination of transvaginal ultrasound and serial serum beta-human chorionic gonadotrophin levels. Diagnosis is often delayed and these tests are time-consuming and costly, both psychologically to the patient and financially to health services. The development of a biomarker that can differentiate a tubal ectopic from an intrauterine implantation is therefore important. In the pre-genomic era, a one-by-one scientific approach has revealed over 20 candidate biomarkers that could be used as a test to diagnose ectopic pregnancy although at present their clinical utility is very limited. These biomarkers cluster into themes: markers of abnormal embryo/trophoblast growth, markers of abnormal corpus luteum function, markers of a growing pregnancy in the Fallopian tube, markers of inflammation and peritoneal irritation, and uterine markers of normal implantation. It is likely that this thematic approach will facilitate the identification of newer biomarkers using microarray technology and inform the development of investigative paradigms using multiple markers at the time of presentation.

Creatine phosphokinase in ectopic pregnancy revisited: significant diagnostic value of its MB and MM isoenzyme fractions

OBJECTIVE

Although evidence on elevated creatine phosphokinase (CPK) as a tool for the diagnosis of ectopic pregnancy (EP) is rather conflictive, no previous study on CPK isoenzyme levels and their relative ratio was found in the literature.

STUDY DESIGN

Forty women with EP, 20 with intrauterine (IU) abortive gestation, and 20 regular pregnant women (controls) were studied. Serum total CPK, CPK-MB, and CPK-MM levels were measured at the time of presentation and 24 hours after surgery. Relative operating characteristic (ROC) curves were plotted.

RESULTS

Women with EP had significantly higher CPK concentrations and a significantly decreased CPK-MB relative ratio (CPK-MB%), compared with both women with IU abortive pregnancy and controls. The ROC curves demonstrated a significant discriminatory ability of both increased total CPK and decreased CPK-MB% ratio for the diagnosis of EP.

CONCLUSION

Determination of CPK isoenzyme fractions can significantly enhance the diagnostic value of total maternal CPK in the prediction of ectopic pregnancy.

Receiver operator characteristics and diagnostic value of progesterone and CA-125 in the prediction of ectopic and abortive intrauterine gestations

OBJECTIVE

The study was designed to investigate the predictive value of progesterone and CA-125 in the diagnosis of ectopic pregnancy (EP) and inevitable miscarriage.

METHODS

Forty women with EP, 20 with intrauterine (IU) abortive gestation and 20 regular pregnant women (controls) were studied. IU abortive and EP were confirmed and treated by surgery. Serum progesterone and CA-125 levels were measured at the time of presentation and 24h after surgery.

RESULTS

Women with EP had significantly lower progesterone concentrations, compared to both women with IU abortive pregnancy and controls. Women with IU abortion had significantly higher CA-125 levels, compared to the other two groups. When using a progesterone concentration of less than 10.75 ng/ml as a cut-point for the diagnosis of EP, sensitivity, specificity, positive and negative predictive values were 85%. When using CA-125 concentration of more than 41.9 U/ml as a threshold for the diagnosis of IU abortive pregnancy, sensitivity was 80%, specificity 87%, the positive predictive value was 66% and the negative predictive value 93%.

CONCLUSION

The measurement of progesterone and CA-125 levels is useful in discriminating ectopic and intrauterine abortive from normal gestations.

Meta-analysis of diagnostic test accuracy assessment studies with varying number of thresholds

Current meta-analytic methods for diagnostic test accuracy are generally applicable to a selection of studies reporting only estimates of sensitivity and specificity, or at most, to studies whose results are reported using an equal number of ordered categories. In this article, we propose a new meta-analytic method to evaluate test accuracy and arrive at a summary receiver operating characteristic (ROC) curve for a collection of studies evaluating diagnostic tests, even when test results are reported in an unequal number of nonnested ordered categories. We discuss both non-Bayesian and Bayesian formulations of the approach. In the Bayesian setting, we propose several ways to construct summary ROC curves and their credible bands. We illustrate our approach with data from a recently published meta-analysis evaluating a single serum progesterone test for diagnosing pregnancy failure.

Serum concentrations of interleukin-2R (IL-2R), IL-6, IL-8, and tumor necrosis factor alpha in patients with ectopic pregnancy

OBJECTIVE

To investigate the diagnostic relevance of serum cytokine concentrations in ectopic pregnancy (EP).

DESIGN

Cohort study.

SETTING

University hospital.

PATIENT(S)

Seventeen women with EP, 22 women with miscarriage, and 33 women with normal intrauterine pregnancy, at comparable stages of gestation.

INTERVENTION(S)

Interleukin (IL)-2 receptor, IL-6, IL-8, and tumor necrosis factor alpha (TNF-alpha) determination by immunoradiometric assay.

MAIN OUTCOME MEASURE(S)

Serum concentrations of progesterone, beta-hCG, IL-2R, IL-6, IL-8, and TNF-alpha.

RESULT(S)

Serum levels of IL-6 were higher in women with EP than in those with miscarriage and normal pregnancy. Serum levels of TNF-alpha were higher in women with EP than in those with miscarriage and normal pregnancy. Serum levels of IL-8 were higher in women with EP than in those with miscarriage and normal pregnancy. An IL-8 cutoff of >40 pg/mL predicted EP with a sensitivity of 82.4%, a specificity of 81.8%, and positive and negative predictive values of 58.3% and 93.8%. No difference in serum IL-2R levels was found among the groups.

CONCLUSION(S)

Serum IL-8, IL-6, and TNF-alpha concentrations are higher in women with EP than in those with miscarriage and normal pregnancy. Further studies are needed to determine their diagnostic value.

Serum levels of myoglobin, creatine phosphokinase, and smooth muscle heavy-chain myosin in patients with ectopic pregnancy

STUDY OBJECTIVE

Serum markers of smooth muscle destruction have been shown to be elevated in ectopic pregnancy, but they remain of questionable clinical utility. Our goal was to determine the clinical utility of 3 markers of smooth muscle destruction: creatine phosphokinase (CPK), smooth muscle heavy-chain myosin (SMHC), and myoglobin.

METHODS

This was a prospective cohort study, with consecutive enrollment of all women in the first trimester of pregnancy who presented to our urban emergency department with complaints of lower abdominal pain, vaginal bleeding, or both. Patients were excluded from the study if there was a history of recent surgery or major trauma. Data analysis included receiver operating characteristic (ROC) curve, 95% confidence intervals (CIs), and a regression model.

RESULTS

A total of 378 patients were enrolled, with 61 patients diagnosed with an ectopic pregnancy, and 317 patients placed in the non-ectopic pregnancy group with other diagnoses. ROC curve analysis revealed an area under the curve of 0.56 (95% CI 0.51 to 0.61) for CPK, 0.63 (95% CI 0.59 to 0.68) for SMHC, and 0.58 (95% CI 0.53 to 0.63) for myoglobin. A regression model analyzing the effects of race, maternal age, estimated gestational age, and serum levels of human chorionic gonadotropin beta-subunit found no significant confounders.

CONCLUSION

Although there is a statistically significant elevation in the serum levels of SMHC, the range of values seen is too large to allow SMHC to be a useful screening tool.

Serum levels of smooth muscle heavy-chain myosin in patients with ectopic pregnancy

STUDY OBJECTIVE

Previous studies have suggested that serum markers of smooth muscle destruction have utility in predicting ectopic pregnancy. Our goal was to determine whether a novel marker of muscle destruction, smooth muscle heavy-chain myosin (SMHC), is elevated in the serum of patients with ectopic pregnancy.

METHODS

We conducted a prospective cohort study, with consecutive enrollment, of all women in the first trimester of pregnancy who presented to our urban emergency department with complaints of lower abdominal pain with or without vaginal bleeding. Patients were excluded if there was a history of recent surgery or major trauma. Means were compared using 2-tailed Student's t test with P values less than.05 set for significance. Data analysis included calculation of receiver operating characteristic (ROC), 95% confidence intervals (CIs), and a regression model.

RESULTS

A total of 175 patients were enrolled; ectopic pregnancy was diagnosed in 29, and 146 had other diagnoses. Patients with ectopic pregnancy had a mean serum SMHC concentration of 2.53 ng/dL (95% CI 1.84 to 3.22), whereas those in the non-ectopic pregnancy group had a mean concentration of 1.41 ng/dL (95% CI 1.23 to 1.60; P <.0001). ROC analysis demonstrated an area under the curve of 0.72 (95% CI 0.65 to 0.79). Regression analysis to examine confounders in each group analyzed the effects of race, maternal age, estimated gestational age, and serum levels of human chorionic gonadotropin beta-subunit. Our analysis identified only a positive correlation between estimated gestational age and SMHC in the non-ectopic pregnancy group.

CONCLUSION

There is a statistically significant elevation of serum SMHC levels in tubal pregnancy, although our data suggest that the assay has limited clinical utility as a lone marker for ectopic pregnancy. Further investigation is needed to determine whether the assay has a role as an adjunct in the evaluation of suspected ectopic pregnancy.

Serum creatine kinase is an unreliable predictor of ectopic pregnancy

OBJECTIVE

To compare serum creatine kinase (CK) values in patients with ectopic pregnancy vs patients with threatened miscarriage or normal pregnancy.

METHODS

An observational case-control study was performed at an urban teaching hospital. Pregnant women with a quantitative beta-hCG obtained for suspicion of ectopic pregnancy were evaluated. Excluded were cases with recent trauma, i.m. injections, surgery, or history of heart, liver, or muscle disease. The serum beta-hCG and CK values were recorded and compared between groups with 1-way ANOVA and Tukey's multiple comparison procedure at the overall 0.05 level.

RESULTS

The 15 ectopic, 28 threatened miscarriage, and 21 normal pregnancy cases were of similar gestational ages (p = 0.2), ranging from 3 to 12 weeks. Although the CK values for ectopic pregnancy (88.8 +/- 33.6 IU/L) exceeded those for threatened miscarriage (65.9 +/- 59.0 IU/L) and normal pregnancy (56.0 +/- 38.1 U/L) (p = 0.02), there was significant overlap between groups. CK values were at or above a cutoff of 74 IU/L in 80% (95% confidence interval: 52-96%) of ectopic pregnancies, 25% (11-45%) of threatened miscarriages, and 14% (3-36%) of normal pregnancies.

CONCLUSIONS

Although the ectopic pregnancy population is characterized by a higher mean CK than are patients with threatened miscarriage or a normal pregnancy, a significant overlap in CK values makes use of this serum marker unreliable for detecting ectopic pregnancy.