Intermediate Outcome and Risk Factor Assessment of Bovine Vascular Heterografts used as AV-Fistulas for Hemodialysis Access

OBJECTIVES

This observational study was set up to prospectively follow all bovine heterograft (ProCol) fistulas implanted for hemodialysis access between 1998 and 2002.

METHODS

ProCol was implanted if autogenous vein was not available or if patients presented with a history of failed, infected or otherwise complicated ePTFE grafts and/or on immunosuppressive therapy. Fistula patency was the primary outcome; secondary outcomes were clinical events and the rate of access revisions.

RESULTS

Sixty-two ProCol grafts were implanted in 56 patients. The mean primary (PP) and secondary patency (SP) was 334 (SEM 57) and 528 (SEM 59) days, respectively. Coronary heart disease was associated with a significantly better SP (OR 0.2, 95% CI 0.1-0.9) whilst diabetes mellitus was associated with a significantly worse SP (OR 0.2, 95% CI 0.1-0.9). Reinterventions were performed at a mean rate of 1.23 (SEM 0.17) per fistula. The relative risk of access revision was significantly higher in patients with diabetes mellitus (OR 9.2, 95% CI 2.3-37.2).

CONCLUSIONS

ProCol grafts, used for AV-fistulas, demonstrate acceptable patency rates in high-risk haemodialysis patients. Diabetes mellitus jeopardizes the patency of these fistulas and is associated with a high revision rate.

Das Vakuumsystem in der Gefäßchirurgie

Since the first use of vacuum-assisted therapy (V.A.C.) in wound care, the indications of this therapy have rapidly expanded. Vascular surgery presents many types of problematic wounds. In the current cost conscious atmosphere, there is a great demand for simple and effective therapies. The V.A.C. system has a lot of potential in the management of vascular wounds. In this article we present indications for vacuum-assisted therapy in vascular surgery: chronic leg ulcers, mesh skin graft, wound care after fasciotomy for compartment syndrome, problematic inguinal wound, false aneurysms, diabetic foot gangrene and amputations with marginal circulations.

Bovine mesenteric vein graft (ProCol) in critical limb ischaemia with tissue loss and infection

OBJECTIVES

Poor results have been reported following infrainguinal reconstructions using heterogenous grafts. The objective of this study was to assess the use of bovine mesenteric vein (ProCol) graft in patients with critical limb ischaemia (CLI), tissue loss/infection and no autologous vein available for reconstruction.

METHODS

Prospective analysis of 32 patients with CLI and tissue loss/infection, in whom reconstruction with ProCol was undertaken between October 1999 and May 2002.

RESULTS

The primary patency rate was 16% at 1 month. After thrombectomy, the secondary patency rate was 50% at 1 month and 26% at 14 months. No graft infections were seen. Aneurysmal dilatation of the graft occurred in 2 (6%). Limb salvage at 14 months was 47%.

CONCLUSION

In patients with critical limb ischaemia, tissue loss/infection and no available vein, the ProCol graft may be an alternative. However, primary patency is a problem. In situations without tissue loss/infection, where the risk of graft infection is less, prosthetic material may be a better alternative.

[How frequent are diabetes-related amputations of the lower limbs in Germany? An analysis on the basis of routine data]

BACKGROUND AND OBJECTIVE

The total number of lower limb amputations in Germany as well as the frequency of lower limb amputations attributable to diabetes is unknown. Currently available estimates are based on regional studies resulting in different totals. The aim of this study was to perform a census of all lower limb amputations in Germany in order to obtain valid estimates of the number of amputations attributable to diabetes mellitus in Germany.

PATIENTS AND METHODS

Hospital performance and expenditure statistics were used to obtain a comprehensive count of lower limb amputations. The number of amputations in diabetic patients as well as the number of diabetes-related amputations were assessed by calculating the proportion of diabetes among amputees as well as attributable amputations standardized to the age and gender distribution in Germany in 2001, using routine data from the Local Health Insurance Funds (AOK) as well as previous analyses from Germany.

RESULTS

In 2001, 43,544 lower limb amputations and additional 3,981 revisions of amputations were performed in Germany. Among these almost 29,000 lower limb amputations were estimated to be performed in diabetic patients. More than 26,000 lower limb amputations per year were estimated to have been attributable to pre-existing diabetes mellitus.

CONCLUSIONS

Lower limb amputations as a complication of diabetes mellitus are more frequent in Germany than previously estimated. Intensified prevention and therapy--as intended in disease management programs--are urgently needed to decrease the complications of diabetes and ultimately to reduce diabetes mellitus-related costs.

Idiopathic hypertrophic pachymeningitis

BACKGROUND

Hypertrophic pachymeningitis is an uncommon disorder that causes a localized or diffuse thickening of the dura mater and has been associated with rheumatoid arthritis, syphilis, Wegener's granulomatosis, tuberculosis, and cancer. Few series of the idiopathic variety have been described, particularly with respect to MRI correlation to clinical outcome and treatment.

OBJECTIVE

To investigate the clinical and laboratory evaluation, course, and treatment of patients with idiopathic hypertrophic pachymeningitis (IHP), to correlate the MRI findings with the clinical course, and to review the literature on IHP.

METHODS

Retrospective case series of 12 patients (9 men, 3 women), with a mean age of 55 years (range 39 to 88 years), who had IHP by imaging studies, meningeal or orbital biopsy, or both. The clinical features, laboratory evaluation, contrast-enhanced MRI, treatment, and clinical outcome were documented for each case. The mean duration of follow-up was 3.5 years (range 3 months to 16 years).

RESULTS

The main clinical features at presentation were headache (11 cases), loss of vision (7 cases), diplopia (4 cases), papilledema (2 cases), other cranial nerve involvement (3 cases), ataxia (2 cases), and seizures (1 case). On the initial MRI, the location of abnormal enhancement of the dura mater correlated with the clinical findings and the sphenoid wing area was affected in all patients. The sedimentation rate was elevated in five cases. The CSF had increased protein in six cases and lymphocytosis in four cases. Biopsy of the dura mater in five cases and the orbital soft tissue in one case showed infiltrates of small mature lymphocytes, plasma cells, and epithelioid histiocytes, but no neoplasia, vasculitis, or infectious agents. Cultures of the CSF and biopsy material remained sterile. Corticosteroid therapy improved the vision in 7 of 8 cases and controlled headache in 10 of 11 cases. Five cases had partial improvement of other neurologic symptoms and signs. Recurrence developed with steroid tapering in six cases. One case had progressive deterioration and died. In four cases methotrexate or azathioprine was added with reduction of the steroid dose. Follow-up MRI performed in 11 patients correlated 80% with the clinical state (p = 0.01).

CONCLUSION

IHP can be suspected on MRI and defined pathologically on biopsy. Untreated, the clinical course is usually marked by severe headache and progressive neurologic deterioration and vision loss. Although initially steroid-responsive, clinical manifestations frequently recur with corticosteroid taper, requiring the addition of immunosuppressive agents in some cases.

[Why are babies born at night at increased risk of early neonatal mortality?]

BACKGROUND

Increased perinatal and neonatal mortality rates have been previously reported in night-time births compared with births during the day. This effect has been attributed to decreased quality of medical care during the night. However, alternative explanations exist such as decreased birth-weight of night births. The objective of this study was to further investigate this relationship.

MATERIALS AND METHODS

Data from 590,332 low risk births (singleton births, > or = 2500 g birth-weight, no major congenital anomaly) were obtained from the perinatal birth register of Hesse, Germany, 1990-2000. Outcome was defined as either death during labour or within 7 days of life. Night-time births were defined as births between 9.00 p.m. and 6.59 a.m., otherwise day-time births were assumed. Subgroup analyses and logistic regression analyses were performed to assess whether the excess mortality of night-births might be explained by other factors.

RESULTS

Mortality rates were increased in night-time births (RR = 1.26; 95% CI = 0.94-1.70). This relationship was more pronounced in spontaneous births (RR = 1.58; 95% CI = 0.96-2.61) and emergency cesarean sections (RR = 1.76; 95% CI = 1.10-2.82). Significance persisted after adjusting for numerous potential confounders.

CONCLUSION

Our results confirm an increased mortality risk for night-time births which could not be explained by other accessible risk factors. This suggests that the increased risk at night might be attributable to a reduced availability to provide appropriate medical care in delivery units at night.

DISCUSSION

As mainly the presence of staff is decreased during the night, introduction of better designed shifts can be expected to reduce neonatal mortality.

Evaluation of quantitative ultrasound tissue characterization of the cervix and cervical length in the prediction of premature delivery for patients with spontaneous preterm labor

OBJECTIVE

This study was to evaluate the predictive value of the uterine cervix tissue with the use of quantitative ultrasound gray level analysis for preterm delivery.

STUDY DESIGN

Sixty-eight patients with preterm labor between 20 and 35 weeks of gestation were included. When two-dimensional transvaginal ultrasound measurement of cervical length was completed, a region of interest of constant size was defined in the midsection of the posterior wall, and the tissue-specific gray scale was determined. Preterm delivery of <37 weeks of gestation was sought.

RESULTS

Twenty-eight patients (41.2%) were delivered preterm. The risk for preterm delivery was increased significantly in patients with cervical length of </=2.5 cm (odds ratio, 7.67; 95% CI, 2.4-24.45), with Bishop score of >/=4 (odds ratio, 3.44; 95% CI, 1.21-9.75), and with decreased mean gray scale value (odds ratio, 12.13; 95% CI, 3.69-39.88). Parity and uterine contractions were not significant as predictors for preterm delivery, although the risk for preterm delivery increased with higher parity (odds ratio, 1.8; 95% CI, 0.68-4.79). The risk for preterm delivery remained nearly the same by uterine contractions (odds ratio, 0.92; 95% CI, 0.28-3.01). A mean scale value of </=6.54 had the best cutoff value for the prediction of preterm delivery. For preterm delivery, a mean gray value </=6.54 had a sensitivity of 82.1%, a specificity of 72.5%, a positive predictive value of 67.6%, and a negative predictive value 85.3%. Multiple logistic regression analysis indicated that, even when other variables are considered simultaneously, the mean gray scale value is the single best predictor of preterm delivery.

CONCLUSION

Quantitative ultrasound tissue characterization of the uterine cervix predicts premature delivery and provides additional information in the prediction of potential premature delivery.

Evaluierung der Reproduzierbarkeit dopplersonographischer Messungen in der Geburtshilfe

BACKGROUND

Are obstetric doppler ultrasonographic measurements of the fetal and maternal flow parameters reproducible?

PATIENTS AND METHODS

For internal quality management, doppler ultrasonographic measurements were performed on 81 patients (random screening sample) with an Acuson Sequoia Ultrasound at the Universitätsfrauenklinik Marburg. Successively two experienced investigators measured the umbilical artery, medial cerebral artery, and the uterine arteries. The correlation between the measurements of the two investigators was presented in a spread chart. In order to exclude systematic differences between the measurements, linear regression was analyzed and the distance to the abscissa was calculated. A relative divergence of more than 20% was determined as a non corresponding measurement.

RESULTS

The distance of the linear regression to the abscissa was calculated for the four vessels: umbilical artery 0.4 (95% CI; 0.124 - 0.486), medial cerebral artery 0.9 (95% CI; 0.534 - 1.264), right uterine artery 0.2 (95% CI; 0.124 - 0.305), and left uterine artery 0.2 (95% CI; 0.121 - 0.317). Concerning the four arteries, a divergence of more than 20% between the two investigators was found: umbilical artery 16%, medial cerebral artery 42%, right uterine artery 28%, and left uterine artery 37%.

CONCLUSIONS

Because the interobserver variability was surprisingly high and acceptable correlation could be stated only for the umbilical artery, internal quality standards are essential. Routine use of different devices should be made after careful consideration only, especially if clinical decisions are to be based on them.

[Umbilical blood pH, Apgar scores, and early neonatal mortality]

BACKGROUND

For several decades Apgar scores and umbilical blood pH sampling have been routinely used in the assessment of newborns. The aim of this study was to examine the prognostic value of neonatal survival using population-based data and to put these analyses into context with international studies.

MATERIAL AND METHODS

Data from 513,135 live births from the Perinatal Birth Register of Hesse, 1990 - 1999, were used. Death in the first week of life (early neonatal death) was used as endpoint of analyses. Receiver operator characteristic analyses were employed to compare the prognostic value of Apgar scores and umbilical blood pHs independently of cutoffs used.

RESULTS

Scores and umbilical blood pH showed a strong association with early neonatal morality. The relative risk of early neonatal mortality in term infants with scores 0 - 3 yields a relative risk of 1193 (95 % confidence interval = 801 - 1778) compared with babies born with scores 7 - 10. Scores at 1, 5, and 10 minutes were superior in predicting early neonatal mortality compared to umbilical blood pH, independent of cutoffs used.

CONCLUSIONS

Scores remain essential in the prediction of early neonatal survival. Umbilical blood pH is also strongly and significantly associated with early neonatal death, even though it is much less pronounced than the score.

DISCUSSION

The poor mortality prediction of umbilical blood pH sampling in Hesse compared with umbilical blood pH sampling in a large American delivery unit with a highly standardized measuring routine may be explained by a lower proportion of extremely acidotic infants or may be attributable to a decreased proportion of or to a less unified or less reliable measurement of the umbilical blood pH in Hesse.

[Assessing the impact of delivery unit size on neonatal survival: estimation of potentially avoidable deaths in Hessen, Germany, 1990-2000]

BACKGROUND AND OBJECTIVE

There are only few analyses from Germany on the impact of delivery unit size on neonatal outcome. The objective of this study was to evaluate the influence of delivery unit size on neonatal survival in Germany.

PATIENTS AND METHODS

Data from the perinatal birth register for Hessen for 1990-2000 comprising 640554 births, and the Neonatal Survey for 1989-1997 in Hessen were used. Potentially avoidable deaths were assessed according to delivery unit size and birth weight category. Additionally trend analyses and an extrapolation to potentially avoidable deaths in all of Germany were performed.

RESULTS

Compared to large delivery units, smaller ones showed higher risk adjusted mortality rates. Calculation of potentially avoidable deaths gave an estimate of 257 early neonatal deaths in 11 years. Although trend analyses revealed a decline of potentially avoidable deaths, an extrapolation of such deaths for all of Germany still yielded an estimate of more than 300 potentially avoidable deaths per year using data from 1997-2000 only.

CONCLUSION

A valid inference as to the magnitude of the observed effect remains even in the face of a very cautious interpretation of our results. During the study period of 11 years, more than 200 neonatal deaths could be attributed to the fact that births in Hessen are dispersed among many small hospitals. If this pattern of births in small units is common throughout Germany, it suggests that several hundred neonatal deaths per year may be attributed to this risk factor when extrapolating these results nationally. Further research is necessary to describe the nation-wide magnitude of this problem and to identify the role of underlying causal risk factors more precisely. Additionally policy discussions regarding structural changes in obstetrical care should be undertaken in the meantime, aimed at reducing the observed mortality rates.

Factors associated with differences in antihypertensive drug treatment: results from the MONICA Augsburg Population Surveys 1989/90 and 1994/95

OBJECTIVE

To investigate in a population-based sample of hypertensive men and women the impact of factors that determine frequency and pattern of antihypertensive treatment.

METHODS

We used pooled data of two independent surveys conducted 1989/90 and 1994/95 in the Augsburg region among men and women aged 25 to 74 years. Co-morbidity and cardiovascular risk factors were assessed by questionnaire and examination. Multivariate and polytomous logistic regression analyses were used to assess treatment patterns adjusting for cofactors.

RESULTS

Among a total of 9,795 survey participants, 2,279 men and 1,699 women were hypertensive with 30% of men and 43% of women using antihypertensive drugs. Hypercholesterolemia was unrelated and smoking even inversely related to treatment (adjusted odds ratio OR = 0.7, 95% CI 0.56-0.92). Women were more likely to be treated than men (adjusted OR = 1.6, 95% CI: 1.34-1.82). Furthermore, women on monotherapy used diuretics significantly more often than men (adjusted OR relative to betablocker use 2.8, 95% CI: 1.6-4.8).

CONCLUSIONS

We identified several determinants of drug treatment among hypertensives in the community. During the study period antihypertensive treatment seemed to be determined primarily by clinical disease but not by concomitant cardiovascular risk factor status, such as male gender, smoking, or hypercholesterolemia.

Are we regionalized enough? Early-neonatal deaths in low-risk births by the size of delivery units in Hesse, Germany 1990-1999

BACKGROUND

While agreement exists about the benefits of regionalization for high-risk births, little evidence exists regarding regionalization of low-risk births. The objective of this study was to investigate the impact of regionalization on neonatal survival focussed on low-risk births.

METHODS

Data from the perinatal birth register of Hesse, 1990-1999 were used comprising detailed information about 582,655 births covering more than 95% of all births in Hesse. Outcome events were death during labour or within the first 7 days of life (early-neonatal death). Mortality rates and corresponding 95% CI were calculated according to hospital volume measured by births per year and birthweight categories.

RESULTS

Birthweight-specific mortality rates were lowest in large delivery units and highest in smaller delivery units. This gradient was especially pronounced within low-risk births and was also confirmed in several logistic regression models adjusting for additional risk factors. A more than threefold mortality risk was observed in hospitals with <500 births/year compared with hospitals with >1,500 births/year (odds ratio = 3.48; 95% CI: 2.64-4.58). Further trend analyses indicated that prenatal prevention programmes and the increasing usage of modern prenatal diagnostic procedures have not reduced this gradient in recent years.

CONCLUSIONS

This analysis presents an urgent public policy issue of whether such elevated risk in smaller delivery units is acceptable or if further consolidation of birthing units should be considered to reduce early-neonatal mortality.

[Anterograde intramedullary tibio-talo calcaneus arthrodesis (aIMTCA) with spongiosaplasty in pseudarthrosis]

Pseudarthrosis occur in 65% of all ankle joint arthrodesis. From the therapeutical point of view we make a distinction between vital (hypertrophic) and avital (hypotrophic) respectively stable and instable pseudarthrosis. The hypotrophic forms demand an additional cancellous or bone grafting. Especially instable pseudarthrosis have to be treated with a biological osteosynthesis. In the hindfoot the so called compression arthrodesis made one's way. But there is still a discussion about the best method, intern or extern fixation. We report about a case of hypotrophic pseudarthrosis with a mal-position occurring after an ankle joint arthrodesis with a Charnley-Fixateur. A fusion of the ankle joint could be carried out with a proximal respectively anterograde intramedullary nail and allogene cancellous graft.

[Internet communication between family physicians and the university hospital]

The potential of electronic communication in medicine is assessed based on an analysis of a pilot project pertaining to internet based communication among referring and hospital physicians. Advantages of electronic data exchange in medicine pertain to speed and capacity for data transfer, availability of data and data integration, ultimately enabling consistent medical case management. Quality requirements of electronic communication of medical data are related to safety, availability, data integration, potential for case management and system qualities. Medical efficiency can be increased by use of electronic communication only if complex functions beyond the substitution of conventional mail by e-mail are implemented and an exhaustive use of the technology can be achieved.

[The predictive value of a classification for proliferative diabetic vitreoretinopathy]

BACKGROUND

Kroll's classification of proliferative diabetic vitreoretinopathy (PDVR) defines stage A (vitreoretinal proliferations without retinal detachment), stage B (partially detached retina not involving the macula), stage C (partially detached macula) and stage D (completely detached macula). The purpose of this study was to analyse the prognostic value of Kroll's classification in respect of the postoperative results of vitreoretinal surgery based on our group of patients.

PATIENTS AND METHODS

The charts of 563 patients who underwent vitrectomy because of PDVR between 1990 and 1997 were examined retrospectively. Postoperative visual acuity, possible risk factors, frequencies of silicone oil tamponade and revitrectomies were related to the preoperative staging of PDVR. The influence of possible predictive factors on the postoperative visual outcome were evaluated using multivariate logistic regression analysis.

RESULTS

After vitreoretinal surgery mean postoperative visual acuity was significantly better in stage A compared to stage C (p < 0.01) or D (p < 0.0001). In 179 out of 563 eyes (31.7 %) revitrectomy (including silicone oil removal) was required and in 51 eyes (9.1 %) more than one revitrectomy was performed. Silicone oil tamponade was used in 22 out of 253 eyes (8.7 %) classified as stage A, in 27 out of 201 eyes (13.4 %) of stage B, in 17 out of 78 eyes (21.8 %) of stage C and in 10 of 31 eyes (32.3 %) of stage D. Postoperative increase of visual acuity of more than 3 lines was significantly less frequent in stage B (p < 0.014), C (p < 0.039) and D (p < 0.001) compared to stage A.

CONCLUSION

Kroll's classification for PDVR has a high prognostic value for the postoperative visual outcome and level of surgical risk management. Thus patients with good prognosis can be identified easily, facilitating the decision for surgery.

An adjustment for a post-randomization variable in the comparison of two treatments for survival

A method is proposed to infer the randomized treatment effect on survival after an adjustment for a post-randomization variable. The post-randomization variable is made independent of the treatment assignment and is considered a surrogate for baseline prognostic factors. The relationship between the post-randomization surrogate and baseline prognostic factors for survival is considered smooth, but otherwise unknown. The effect of these factors on survival is modelled using the Cox proportional hazards model with a semi-parametric relative risk function. Likelihood based estimates and tests for the treatment effect are demonstrated. An example from a randomized clinical trial in cancer illustrates the methodology.

Pairwise rank-based likelihood for estimation and inference on the mixture proportion

We consider the problem of estimation and inference on the mixture parameter in the two-sample problem when sample data from the two distributions as well as from a third population consisting of a mixture of the two are used. Under a general nonparametric model, where the relationship between the two populations is unspecified, we develop a pairwise rank-based likelihood. Simultaneous inference on the mixture proportion and a parameter representing the probability an observation from one population is greater than an observation from the other population is based on this likelihood. Under some regularity conditions, it is shown that the maximum pairwise rank likelihood estimator is consistent and has an asymptotic normal distribution. Simulation results indicate that the performance of this statistic is satisfactory. The methodology is demonstrated on a data set in prostate cancer.