Delaying clinical events among patients with non-valvular atrial fibrillation treated with oral anticoagulants: Insights from the ARISTOPHANES study

BACKGROUND

Oral anticoagulants (OACs) mitigate stroke and systemic embolism (SE) risk in non-valvular atrial fibrillation (AF) patients but can increase the risk of major bleeding (MB). This study analyzed the gains in event-free time for these outcomes among OAC treatment options represented in the ARISTOPHANES study.

METHODS

This sub-analysis consisted of NVAF patients who initiated warfarin, apixaban, dabigatran, or rivaroxaban from 01JAN2013-30SEP2015, with data pooled from Medicare and 4 US commercial claims databases. Propensity score matching was conducted between non-vitamin K antagonist OAC (NOAC) and warfarin cohorts in each database and results were pooled. Laplace regression was used to evaluate the delay in time to stroke/SE and MB events between NOACs and warfarin and between NOACs after the first 12-months of follow-up.

RESULTS

The population included 466,991 patients (167,413 warfarin; 108,852 apixaban; 37,724 dabigatran; and 153,002 rivaroxaban). Event-free time gain (95% confidence interval) for apixaban versus warfarin was 101 days (78- 124) for stroke/SE and 116 (103- 130) days for MB. The gain in event-free time for dabigatran versus warfarin was 45 days (3- 87) for stroke/SE and 92 (68- 116) days for MB. The gain in event-free time for rivaroxaban versus warfarin was 63 days (42- 84) for stroke/SE but event-free time decreased by 18 (-31-6) days for MB.

CONCLUSIONS

Over 12 months after initiation, apixaban and dabigatran conferred progressive increases in event free time for stroke/SE and MB vs warfarin, whereas rivaroxaban conferred an increase in stroke/SE-free time but a loss in MB-free time vs warfarin.

Impact of apixaban treatment discontinuation on the risk of hospitalization among patients with nonvalvular atrial fibrillation and COVID-19

INTRODUCTION

This study evaluated the risk of hospitalization among nonvalvular atrial fibrillation (NVAF) patients with an outpatient COVID-19 diagnosis who discontinued vs continued apixaban treatment.

METHODS

Adult patients with NVAF with an apixaban prescription prior to an outpatient COVID-19 diagnosis were identified from Optum Clinformatics claims database (1 April 2020-31 March 2021). Continuers were those who continued apixaban as of the index date (date of initial outpatient COVID-19 diagnosis) and discontinuers were those who had the last day of apixaban supply on or before index. Patients were followed from COVID-19 diagnosis to change of continuation/discontinuation status, switch, death, end of continuous coverage or study end, whichever occurred first. Inverse probability treatment weighting (IPTW) was performed to balance cohorts. Cox proportional hazard models were used to compare the risk of all-cause hospitalization and hospitalization for ischemic stroke (IS), venous thromboembolism (VTE), myocardial infarction (MI), bleeding and mortality.

RESULTS

A total of 7869 apixaban patients with COVID-19 were included: 6676 continuers (84.8%) and 1193 discontinuers (15.2%). Compared with continuers, discontinuers had a higher risk of all-cause hospitalization (hazard ratio [HR]: 1.23; 95% confidence interval [CI]: 1.08-1.40), IS (HR: 2.00; 95% CI: 1.03-3.87), VTE (HR: 2.37; 95% CI: 1.06-5.27) and mortality (HR: 2.28; 95% CI: 1.85-2.80). There were no significant differences in the risk of MI (HR: 1.01; 95% CI: 0.54-1.90) or bleeding-related hospitalization (HR: 1.13; 95% CI: 0.73-1.76).

CONCLUSION

NVAF patients with COVID-19 who discontinued apixaban had a higher risk of hospitalization and thrombotic events vs those who continued apixaban, with no significant difference in bleeding-related hospitalization.

Real-world assessment of anti-platelet therapies for recurrent stroke prevention in non-atrial fibrillation Japanese patients after recent ischemic stroke or transient ischemic attack

Background

Stroke is one of the leading causes of cardiovascular-related deaths and disability for adults in Japan and is more commonly seen among the elderly. The risks of developing a secondary stroke resulting in permanent damage after the incident ischemic stroke (IS)/transient ischemic stroke (TIA) are very high. It is critical to understand the treatment landscape for the secondary stroke prevention (SSP) and unmet needs of patients with prior IS/ TIA events.

Purpose

To evaluate the antiplatelet therapy (APT) treatment patterns for SSP after first hospitalization for IS/TIA events among the Japanese population.

Methods

Japan's Medical Data Vision (MDV) from Q12011 to Q22021 was used for this study. MDV is a hospital-based claims database covering approximately 35.5 million individuals in the inpatient and outpatient settings among 438 hospitals. Adult patients with an inpatient primary diagnosis of IS/TIA during the index period were identified. Patients require at least one medical claim each quarter within the 1 year before and after index date to ensure longitudinal analysis. Atrial fibrillation patients or patients on oral anticoagulant use were excluded. Patients' characteristics, treatment pattern and duration were evaluated.

Results

Of 18,948 patients in this study, the mean age was 75 years and 36.7% were female; 91.5% were treated with APT and 8.5% were untreated within 90 days of hospital discharge. Among 17,332 APT treated patients, 76.9% were initiated on single APT (SAPT), 22.7% were initiated on dual APT (DAPT), and <1% were initiated on multiple APT (MAPT). The most used SAPT were aspirin (ASA; 33.2%), clopidogrel (28.7%) or cilostazol (14.8%) and the most used DAPT were ASA+clopidogrel (15.1%), ASA+cilostazol (4.2%) or cilostazol+clopidogrel (2.7%). The median duration of APT was 320, 414 and 411 days for patients who initiated ASA, clopidogrel and cilostazol, respectively. The median duration of APT for patients who initiated ASA+clopidogrel, ASA+cilostazol and cilostazol+clopidogrel was 298, 359 and 473 days respectively. Of patients initiated on ASA+clopidogrel, 52.4% were de-escalated to SAPT (71% clopidogrel, 29% ASA; median duration of 20 days); 36.2% of patients initiated on ASA+cilostazol were de-escalated to SAPT within a median of 19 days (84% cilostazol, 16% ASA); lastly, 54.4% of patients initiated on cilostazol+clopidogrel de-escalated to SAPT within a median of 35 days (76% cilostazol, 24% clopidogrel). Two years after initial hospitalization of IS/TIA, 52%-56% discontinued APT treatments among those previously receiving SAPT while 46%-57% of patients receiving DAPT discontinued treatment.

Conclusion

Majority of patients at risk of secondary stroke received APT. Further analyses are needed to explore reasons for early APT discontinuation, for no APT use, and to evaluate outcomes of patients in this study.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): This study was sponsored by Bristol Myers Squibb and Janssen Research & Development, LLC. – Anonymised and used for statistical purposes only

Effectiveness and safety of oral anticoagulants in non-valvular atrial fibrillation patients with prior bleeding events: a retrospective analysis of administrative claims databases

Introduction

There are a paucity of real-world data examining effectiveness and safety of non-vitamin K antagonist oral anticoagulants (NOACs) and warfarin in nonvalvular atrial fibrillation (NVAF) patients with prior bleeding.

Methods

This retrospective analysis included data from 5 insurance claims databases and included NVAF patients prescribed OACs with prior bleeding. One-to-one propensity score matching was conducted between NOACs and warfarin and between NOACs in each database. Cox proportional hazards models were used to evaluate the risk of stroke/systemic embolism (SE) and MB.

Results

A total of 244,563 patients (mean age 77; 50% female) with prior bleeding included 55,094 (22.5%) treated with apixaban, 12,500 (5.1%) with dabigatran, 38,246 (15.6%) with rivaroxaban, and 138,723 (56.7%) with warfarin. Apixaban (hazard ratio [HR]: 0.76 [95% CI: 0.70, 0.83]) and rivaroxaban (HR: 0.79 [95% CI: 0.71, 0.87]) had a lower risk of stroke/SE vs. warfarin. Apixaban (HR: 0.67 [95% CI: 0.64, 0.70]) and dabigatran (HR: 0.88 [95% CI: 0.81, 0.96]) had a lower risk of MB vs. warfarin. Apixaban patients had a lower risk of stroke/SE vs. dabigatran (HR: 0.70 [95% CI: 0.57, 0.86]) and rivaroxaban (HR: 0.85 [95% CI: 0.76, 0.96]) and a lower risk of MB than dabigatran (HR: 0.73 [95% CI: 0.67, 0.81]) and rivaroxaban (HR: 0.64 [95% CI: 0.61, 0.68]).

Conclusions

In this real-world analysis of a large sample of NVAF patients with prior bleeding, NOACs were associated with similar or lower risk of stroke/SE and MB vs. warfarin and variable risk of stroke/SE and MB against each other.

Supplementary information

The online version contains supplementary material available at 10.1007/s11239-022-02660-2.

Data on NOAC effectiveness and safety in NVAF patients with prior bleed history are lacking.

This study included data on OAC-treated NVAF patients with a history of bleeding.

NOACs were associated with similar or lower risk of stroke/SE and MB vs. warfarin.

NOACs were associated with variable risk of stroke/SE and MB against each other.

This study further demonstrated the effectiveness and safety profile when comparing NOACs to warfarin. The findings could aid to inform the discussion on the benefits and risks in the decision making process for NVAF patients who had a prior bleed.

Effectiveness and safety of non-vitamin K antagonist oral anticoagulants versus warfarin among nonvalvular atrial fibrillation patients with prior bleeding events

Background

Patients with non-valvular atrial fibrillation (NVAF) use oral anticoagulants such as warfarin or non-vitamin K antagonist oral anticoagulants (NOACs) for the prevention of stroke. However, the effectiveness and safety of warfarin and NOACs can be influenced by pre-existing patient comorbidities, such as a history of bleeding, and limited evidence are available to inform the choice of the most appropriate anticoagulant treatment for NVAF patients with bleeding history.

Purpose

This study used five United States insurance claims databases to evaluate the risk of stroke/systemic embolism (S/SE) and major bleeding (MB) among NVAF patients with prior bleeding events who were prescribed NOACs versus warfarin.

Methods

This retrospective observational study used data from 5 databases (CMS Medicare and four commercial databases, covering >180 million beneficiaries) to select adult NVAF patients who were treated with apixaban, dabigatran, rivaroxaban, or warfarin (01JAN2013–30JUN2019). Patients were required to have a prior bleeding event, defined as a hospitalization with a diagnosis for intracranial hemorrhage (ICH), gastrointestinal (GI) bleeding or bleeding at other key sites prior to or during the index treatment episode. In each database, three 1:1 NOAC-warfarin propensity-score-matched (PSM) cohorts were created before pooling the results. Outcome measures were time to first stroke/SE, (ischemic stroke, hemorrhagic stroke, and SE), and time to first MB (gastrointestinal bleeding, intracranial hemorrhage, and MB at other key sites), and were measured from the index treatment episode to treatment discontinuation or switch, death, health plan disenrollment, or end of study period. Hazard ratios of S/SE and MB were calculated using Cox proportional hazards models.

Results

Among the eligible NVAF population, 8.2% of patients had a prior bleeding event (ICH: 12.3%; GI: 60.7%; Other: 27.0%). After PSM, a total of 43,092 apixaban-warfarin, 11,295 dabigatran-warfarin, and 32,723 rivaroxaban-warfarin patient pairs with prior bleeding were selected with a mean follow-up of 8–9 months. Apixaban and rivaroxaban were associated with a lower risk of S/SE, and dabigatran was associated with a similar risk of S/SE when compared to warfarin. Apixaban and dabigatran were associated with a lower risk of MB, and rivaroxaban was associated with a similar risk of MB, compared to warfarin (Figure).

Conclusion

Among NVAF patients with prior bleeding events, NOACs were associated with varying risks of S/SE and MB compared to warfarin. These results can help inform healthcare providers concerning the impact of OAC treatment in NVAF patients with history of bleeding.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bristol-Myers Squibb Company and Pfizer, Inc.

Time at home among nonvalvular atrial fibrillation patients treated with non-vitamin K antagonist oral anticoagulants: an ARISTOPHANES analysis

Background

Patient-centered outcomes, such as home time, are becoming increasingly important quality-of-life measures. There are limited data on the impact of oral anticoagulants (OACs) on home time among patients with non-valvular atrial fibrillation.

Purpose

This analysis, based on the previously published ARISTOPHANES study, used five US insurance claims databases (CMS Medicare and four commercial databases) to compare home time among NVAF patients who were prescribed non-vitamin K antagonist OACs (NOACs).

Methods

Adult NVAF patients who were newly prescribed apixaban, dabigatran, or rivaroxaban (01JAN2013–30SEP2015) were selected. Time at home was calculated as the number of days from the index date (NOAC prescription) without any of the following: an inpatient, skilled nursing facility (SNF) or nursing facility, hospice, or inpatient rehabilitation facility admission. Time at home and without external AF-related care was defined as days from index date without any events from the home time endpoint or any days with a claim for bleeding, stroke/systemic embolism (S/SE), AF, or an INR test. Time at home and without external AF-related care were measured during the 180 days of follow-up; patients were required to have been alive and have 180 days of follow-up post index. In each database, three 1:1 NOAC-NOAC propensity-score-matched (PSM) cohorts were created before combining the databases. For each NOAC-NOAC matched cohort, Poisson regression was conducted to compare time at home and time at home without external AF-related care.

Results

After PSM, 37,314 apixaban-dabigatran, 107,236 apixaban-rivaroxaban, and 37,693 rivaroxaban-dabigatran patient pairs were created of which 37–44% had 180 days of follow-up available. Across the NOAC cohorts, approximately 21–25% of patients had an admission to a hospital, SNF, nursing facility, rehabilitation center, or hospice during the 180-day follow-up. The time at home was generally consistent between the NOAC cohorts (177 days); however, apixaban patients had 0.5 more days at home compared to rivaroxaban patients. Across all NOAC cohorts, 7–8% had a claim for a S/SE, 11–15% had a claim for bleeding, and 15–22% had an INR test, while 87–89% of all patients had an AF-claim during the 180-day follow-up. Patients prescribed apixaban had 1 more day at home without external AF-related care compared to dabigatran, and 1.5 more days at home without external AF-related care compared to rivaroxaban. Dabigatran had <1 more day at home without external AF-related care compared to rivaroxaban.

Conclusion

Among NVAF patients treated with NOACs, there were small differences in the time at home and time at home without external AF-related care during the first 6 months of NOAC treatment. As NVAF is a chronic condition, it is important to understand the impact of NOAC treatment on these patient-centered outcomes.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bristol-Myers Squibb Company and Pfizer Inc.

Time at home among nonvalvular atrial fibrillation patients treated with non-vitamin K antagonist oral anticoagulants versus warfarin

Background

Clinical trials and real-world database studies have shown the benefits of non-vitamin K antagonist oral anticoagulants (NOACs) compared to warfarin; however, measures of functional outcomes are critical in evaluating a patient's quality of life. Previous measures of time spent out of hospital in a home setting and time spent receiving disease-related care among non-valvular atrial fibrillation (NVAF) patients are lacking in the current literature.

Purpose

This analysis was based on the previously published ARISTOPHANES study, and used multiple data sources to evaluate the amount of time spent at a patient's home among NVAF patients who were prescribed NOACs versus warfarin.

Methods

This retrospective observational study used US data from CMS Medicare and four commercial databases to select adult NVAF patients who initiated apixaban, dabigatran, rivaroxaban, or warfarin (01JAN2013–30SEP2015). Time at home and time at home without external AF-related care were measured during the 180 days after the index date (OAC prescription). Time at home was defined as days from index date without any of the following: an inpatient, skilled nursing facility or nursing facility, hospice, or inpatient rehabilitation facility admission. Time at home and without external AF-related care was defined as days away from home and days with a claim for bleeding, stroke/systemic embolism, AF, or an INR test. Each day a claim was observed was counted as one day. In each database, three 1:1 NOAC-warfarin propensity-score-matched (PSM) cohorts were created before pooling the results. After PSM, a subgroup of patients who were alive and had ≥180 days of follow-up was created. Poisson regression was conducted in each NOAC-warfarin matched cohort to compare time at home and time at home without external AF-related care.

Results

After matching, a total of 100,977 apixaban-warfarin, 36,990 dabigatran-warfarin, and 125,068 rivaroxaban-warfarin patient pairs were selected. Of those patients, 38–46% had 180 days of follow-up available. Across treatment cohorts, approximately 75% of patients were at home for the 180-day follow-up. Apixaban, dabigatran, and rivaroxaban patients had 1.3, 0.9, and 0.8 more days at home, respectively, compared to warfarin patients. Patients treated with apixaban had 13.4 more days at home without AF-related care compared to warfarin, while dabigatran and rivaroxaban had 11.6 and 11.7 more days at home without AF-related care compared to warfarin. A greater proportion of warfarin patients than NOAC patients had an INR test (81–82% vs 14–21%), and days with INR testing were the main driver for external AF-related care for warfarin patients.

Conclusion

Among NVAF patients treated with OACs, NOACs were associated with a longer time at home and time at home without external AF-related care compared to warfarin. These results can help inform healthcare providers and patients regarding the impact of NOAC treatment in NVAF patients.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bristol-Myers Squibb Company and Pfizer Inc.

Effectiveness and safety of non-vitamin K antagonist oral anticoagulants among nonvalvular atrial fibrillation patients with prior bleeding events

Background

Among non-valvular atrial fibrillation (NVAF) patients with a history of bleeding, there is a reluctance to use oral anticoagulants (OACs) due to concerns about the risk of bleeding associated with OACs. However, lack of OAC treatments for NVAF patients is associated with a higher risk of stroke and mortality. Non-vitamin K antagonist OAC (NOACs) have been approved for the prevention of stroke in NVAF patients. There are limited data comparing the risk of stroke/systemic embolism (S/SE) and major bleeding (MB) between patients prescribed NOACs and with a history of bleeding.

Purpose

This study used multiple United States data sources to evaluate the risk of S/SE and MB among NVAF patients with prior bleeding events who were prescribed NOACs.

Methods

This retrospective observational study used data from CMS Medicare and four commercial databases–covering >180 million beneficiaries. The study selected adult NVAF patients who were prescribed apixaban, dabigatran, or rivaroxaban (01JAN2013–30JUN2019) and had a prior bleeding event which was defined as a hospitalization with a bleeding diagnosis (intracranial hemorrhage [ICH], gastrointestinal [GI] bleeding, or other bleeding sites) prior to or during the index treatment episode. After 1:1 propensity-score-matched (PSM) in each database between NOACs (apixaban-dabigatran, apixaban-rivaroxaban, and dabigatran-rivaroxaban), the resulting patient records were pooled. S/SE and MB (identified by inpatient claims) were captured during the follow-up period, which was defined as the time between the day after the index treatment date and treatment discontinuation or switch, death, end of study period, or end of medical and pharmacy enrollment. Hazard ratios of S/SE and MB were calculated using Cox proportional hazards models.

Results

Of the overall NVAF population treated with NOACs, 6.2% had a prior bleeding event (ICH: 13.5%; GI: 61.8%; Other: 24.6%). After PSM, a total of 11,106 apixaban-dabigatran, 30,665 apixaban-rivaroxaban, and 11,148 dabigatran-rivaroxaban pairs were matched. Apixaban was associated with a lower risk of S/SE compared to dabigatran and rivaroxaban, and dabigatran was associated with a similar risk of S/SE compared to rivaroxaban. Apixaban was associated with a lower risk of MB compared to dabigatran and rivaroxaban, and dabigatran was associated with a lower risk of MB compared to rivaroxaban (Figure).

Conclusions

In this subgroup of NVAF patients with a history of bleeding, apixaban was associated with a lower risk of S/SE and MB compared to dabigatran and rivaroxaban. Dabigatran was associated with a lower risk of MB compared to rivaroxaban. These results are informative for understanding the impact of NOAC treatment in NVAF patients with prior bleeding events.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bristol-Myers Squibb Company and Pfizer, Inc.

An evaluation of semidistributed-pipe-network and distributed-finite-difference models to simulate karst systems

Several different approaches have been developed to model the specific characteristics of karst aquifers, taking account of their inherent complex spatial and temporal heterogeneities. This paper sets out the development of a semidistributed modelling approach for applications in an Irish karst context using urban drainage software. The models have proven to be very useful for different studies, with examples given for the ecohydrology of ephemeral karst lakes, extreme groundwater-flood alleviation, karst network investigation, submarine groundwater discharge, and quantification of different recharge and flow components. The limitations of the approach are also highlighted, in particular not being able to simulate diffuse infiltration and flow paths explicitly across the groundwater catchment. Hence, a more distributed, finite-difference modelling approach using MODFLOW Unstructured Grid (USG) with the newly developed Connected Linear Network (CLN) process is then compared against the semidistributed approach on the same karst catchment. Whilst it has proven difficult to achieve the same levels of model performance in simulating the spring flows in the distributed model compared to the semidistributed model, the ability to interrogate the flow paths at any point on the three-dimensional aquifer is demonstrated, which can give new insights into flows (and potential contaminant transport) through such complex systems. The influence of the proximity of highly transmissive conduits on the flow dynamics through the much-lower transmissive matrix cells in which the network is embedded has been particularly investigated.

Quantifying and Numerically Representing Recharge and Flow Components in a Karstified Carbonate Aquifer

Karstified carbonate aquifers are highly heterogeneous systems characterized by multiple recharge, flow, and discharge components. The quantification of the relative contribution of these components, as well as their numerical representation, remains a challenge. This paper identifies three recharge components in the time and frequency domain. While the analysis in the time domain follows traditional approaches, the analysis of the power spectrum allows frequencies associated with specific spectral coefficients and noise types to be distinguished more objectively. The analysis follows the presented hypothesis that the different frequency-noise components are the result of aquifer heterogeneity transforming the random rainfall input into a sequence of non-Gaussian signals. The distinct signals are then numerically represented in the context of a semidistributed pipe network model in order to simulate recharge, flow, and discharge of an Irish karst catchment more realistically. By linking the power spectra of the modeled recharge components with the spectra of the spring discharge, the information usually gained by classical performance indicators is significantly widened. The modeled spring discharge is well matched in the time and frequency domain, yet the different recharge dynamics explain the signal of the aquifer outlet in different noise domains across the spectrum. This study demonstrates the conjunctive use of frequency analysis in conceptualization of a hydrological system together with modeling and evaluation.

ESR-, ENDOR- und TRIPLE-Untersuchungen zur Tieftemperaturkonformation von Phenoxylsystemen / Studies of the Low Temperature Conformation of Phenoxyls by ESR, ENDOR and TRIPLE-Resonance

In a series of ortho- and para-substituted phenoxyls the coupling of the β-nuclei (H and P) is caused by hyperconjugation and π-σ-mechanisms, leaving open the signs of the combined HFS constants. By examining the ENDOR and TRIPLE spectra these couplings turned out to be negative. Thus the sign of the well known temperature gradient of these parameters, due to hindered rotation of the substituted group, is positive, leading to a planar conformation of the radicals at low temperature.

The role of the adenosinergic pathway in immunosuppression mediated by human regulatory T cells (Treg)

Tumor-induced dysfunction of immune cells is a common problem in cancer. Tumors induce immune suppression by many different mechanisms, including accumulation of regulatory T cells (Treg). Adaptive Treg (Tr1) generated in the tumor microenvironment express CD39 and CD73 ectonucleotidases, produce adenosine and are COX2+PGE2+. Adenosine and PGE2 produced by Tr1 or tumor cells bind to their respective receptors on the surface of T effector cells (Teff) and cooperate in up-regulating cytosolic 3'5'-cAMP levels utilizing adenylyl cyclase isoform 7 (AC-7). In Teff, increased cAMP mediates suppression of anti-tumor functions. Treg, in contrast to Teff, seem to require high cAMP levels for mediating suppression. This differential requirement of Treg and Teff for cAMP offers an opportunity for pharmacologic interventions using selected inhibitors of the adenosine/PGE2 pathways. Blocking of adenosine/PGE2 production by Tr1 or blocking binding of these factors to their receptors on T cells or inhibition of cAMP synthesis in Teff all represent novel therapeutic strategies that used in combination with conventional therapies could restore anti-tumor functions of Teff . At the same time, these inhibitors could disarm Tr1 cells by depriving them of the factors promoting their generation and activity or by down-regulating 3'5'-cAMP levels. Thus, the pharmacologic control of Treg-Teff interactions offers a novel strategy for restoration of anti-tumor Teff functions and silencing of Treg. Used in conjunction with anti-cancer drugs or with immune therapies, this strategy has a potential to improve therapeutic effects by preventing or reversing tumor-induced immune suppression.

[Emergency management of acute angioedema]

Angioedema is an oedematous swelling of the mucosa or submucosa of the skin. Acute angioedema represents a clinical emergency when the pharynx or larynx are involved and breathing of the patient is impaired. For rapid and effective treatment it is necessary to differentiate between allergic and non-allergic angioedema. Three of the five subforms of non-allergic angioedema are mediated by bradykinin: renin-angiotensin-aldosterone system (RAAS)-blocker-induced angioedema (RAE), hereditary angioedema (HAE) and acquired angioedema (AAE). Antihistamines, corticosteroids and adrenalin can be used to treat allergic angioedema but are ineffective in acute attacks of non-allergic angioedema. In these events the bradykinin-B2-receptor antagonist icatibant (in HAE, or RAE) or C1-INH concentrate (in HAE, or AAE) are therapeutic options for rapid alleviation of acute angioedema. The following article gives an overview of the diagnostics and treatment in the emergency situation of "acute angioedema", especially if swelling of the head-and-neck region is present.

The long-term (8-12 years) results of valgus and lengthening osteotomy of the femoral neck

Shortening of the femoral neck and proximal displacement of the greater trochanter are the principal complications following avascular necrosis of the capital epiphysis head in early childhood. We report here the long-term follow-up of a series of osteotomies performed to lengthen the femoral neck and thus to restore the normal anatomy and function of the hip joint. Out of a sample of 24 patients, 15 (62.5%) were reviewed at the end of a mean follow-up of 10 years and 2 months. Fourteen of them (93.3%) had originally complained of pain on walking which varied in severity. After the operation, five were free from pain at the end of the follow-up, 9 still experienced pain on walking, and 1 also reported pain at rest. Before the operation, a positive Trendelenburg's sign was found in 8 of the patients. This was still present in 2 at follow-up. The average perpendicular distance from the center of the femoral head to a horizontal plane passing through the tip of the greater trochanter (the centro-trochanteric distance) was reduced from 33 mm to 7 mm. Apart from correcting the anatomical deformity, it is suggested that this operation may well provide lasting relief from pain and increase the power of the abductor muscles. It may also delay the onset of osteoarthritic change and in this way postpone the necessity for an endoprosthesis.

Treatment of pulmonary artery compression due to fibrous mediastinitis with endovascular stent placement

We present the case of a 32-year-old woman with high-grade right pulmonary artery stenosis secondary to fibrous mediastinitis. The patient was managed with balloon angioplasty and stent placement. Only 15 cases of this nature have been reported in the literature, and this is one of the first to be managed with endovascular stent placement.

Phage diabody repertoires for selection of large numbers of bispecific antibody fragments

Methods for the generation of large numbers of different bispecific antibodies are presented. Cloning strategies are detailed to create repertoires of bispecific diabody molecules with variability on one or both of the antigen binding sites. This diabody format, when combined with the power of phage display technology, allows the generation and analysis of thousands of different bispecific molecules. Selection for binding presumably also selects for more stable diabodies. Phage diabody libraries enable screening or selection of the best combination bispecific molecule with regards to affinity of binding, epitope recognition and pairing before manufacture of the best candidate.

[A new plate for dorsal occipito-cervical fusion. Design, surgical technique, initial clinical results]

A survey of actually practiced methods for cranio-cervical fusion is presented, followed by the description of a new osteosynthesis-plate to solidly fuse this region. The new plate offers a number of advantages when compared with competing procedures. It is rigidly fixed to the occipital bone by five screws, sublaminar wireloops bond the vertebrae to be fused to both branches of the U-shaped plate where the individual loops are positioned into obliquely ascending slots. This safely prevents migration and disengagement resulting in a high initial horizontal and vertical stability allowing for a postoperative care without external support. During the procedure tightening of the wire loops may succeed on reposition of the deformity. The plate exists in two lengths allowing fusion of C0-C2 or more segments of the cervical spine. The typical indication is instability of C0-C2 in rheumatoid arthritis or tumoral lesions of the area. Clinical experience in 7 patients suffering from rheumatoid arthritis (follow-up: 6-31 months) is very positive, fusion has occurred in all cases.

Early surgical treatment for congenital vertical talus

Congenital vertical talus is characterised by a dislocated talonavicular joint in association with an equinus position of the calcaneus. We report the results in 13 operated feet in 10 children, 3 of whom (5 feet) presented with a primary neurological disorder and 2 of whom (3 feet) suffered from arthrogryposis multiplex congenita. The other children were normal. All patients were surgically treated by a one-stage procedure which included reduction of the talonavicular joint and correction of the hindfoot equinus, trying to avoid tendon lengthenings and transfers. The age at operation was between the 3rd and the 6th month of life, with one child being operated on later due to other reasons. The patients were reviewed after an average time of 3.5 +/- 2.2 years. The clinical results were good or excellent in ten feet. Two feet showed partial or complete recurrence and one foot was slightly over-corrected. Radiographic angle measurements (talo-metatarsal I angle and talocalcaneal angle on the anteroposterior radiograph; talocalcaneal, tibiotalar and tibiocalcaneal angles on the lateral radiograph) returned to normal values in the ten good or excellent feet. Early operative treatment for congenital pes vertical talus leads to very satisfactory functional and cosmetic results, usually avoiding extensive procedures including tendon lengthenings and tendon transfers.

[Diagnosis and therapy of coxitis fugax with special reference to the value of ultrasonographY-assisted diagnosis and hip joint puncture]

Between 1984 to 1991 55 children (mean age 7.0 years) were observed with a painful effusion of the hip examined by ultrasound. Children with radiologically diagnosed hip diseases were excluded. In 47 cases we found a transient synovitis of the hip which started at an average interval of 4 days in mean before admission. All children were reexamined 6 weeks after the end of treatment sonographically and clinically, 4 of those revealing incipient Perthes diseases. The primary sonographic right/left difference in amount of effusion (mean) was 4.0 +/- 1.7 mm and after aspiration 1.5 +/- 1.4 mm with a significantly correlation with the amount of aspirated synovial fluid. The radiological findings for a diagnosis of an effusion of the hip were not reliable. Beside the diagnostic signs of the appearance of the aspirated fluid the sonographic assisted aspiration of the hip is an important treatment mode to reduce the intracapsular pressure and the pain of a hip effusion in children.

The influence of physical fitness on automatic and effortful memory changes in aging

A cross-sectional study was carried out in order to determine the influence of cardiovascular fitness on age-related declines in cognitive performance. Forty-eight volunteers were divided into Young (n = 13, 18-27 years), Middle-Aged (n = 22, 60-65 years) and Old (n = 13, 65-88 years) groups and tested on a battery of cardiovascular, pulmonary, hemodynamic, and biochemical tests in order to assess physical fitness. Cognitive performance was evaluated by a variety of memory tasks distributed along an automatic-to-effortful processing continuum. Memory for location and frequency of occurrence were selected as representative of automatic processing, whereas, an auditory free-recall task was selected as representative of effortful processing. Age-related performance declines were observed for the free-recall task, but no such age-dependent association was observed for frequency and location memory. With regard to the influence of physical fitness; the Middle-Aged and Older participants were divided into High and Low Fitness groups and significant differences were observed between these groups for the effortful but not the automatic memory tasks. These data suggest that the relationship between physical fitness and cognitive performance in old age is task dependent. Furthermore, the apparent prophylactic effects of physical fitness on effortful memory, do not appear to extend to cognitive tasks requiring less effortful processing.

[Wound secretions in standard orthopedic surgery interventions using a new kind of closed vacuum drainage. A report of experiences]

One year's experience with 400 closed Redyrob drainage systems in 267 male and female patients has yielded encouraging results, which led to the replacement of the drainage system formerly used in the orthopaedic university clinic in Marburg by the new system. This makes it possible to regulate the suction strength between 0 and 900 mbar and to couple two suction tubes with one container. Drainage without suction and changing of the containers, which may be necessary in the case of large wound surfaces, can be performed without opening the system, which would endanger both patients and clinic personnel. Additional containers were only needed in 2.3%, because of the better filling volume. Thus, the new drainage system also proved to be superior with respect to cost efficiency and disposal. The total amount of wound secretion never exceeded 1620 ml, depending on the type of surgery performed, and there were no cases of infection or bleeding complications. The suction was regulated in 74% of all systems, and after most of the operations for insertion of endoprostheses. The handling of the systems was classed by the staff on the ward as "very good" or "good" in 96% of all cases. These results are discussed in the light of important aspects of wound drainage already mentioned by other authors.

[Autologous cartilage-bone transplantation in the therapy of osteochondrosis dissecans of the knee joint]

This study presents the results of twelve patients, treated by an autologous bone and cartilage transplant for an advanced stage (stage IV and V referring to Rodegerdts and Gleissner, 14) of osteochondritis dissecans of the knee. In a follow up examination after an average time of 3.7 years all patients could be reviewed clinically and radiologically. The clinical results have been very satisfying in all but one patient. Radiologically all patients showed early signs of gonarthrosis, but only in 4 of 12 patients more advanced signs of arthrosis were found. In their own opinion all patients were satisfied with the outcome of the operation, and two of them regarded the result as excellent. Besides the operative technique the indications practising autologous bone-cartilage-transplantation in large osteochondral defects of osteochondritis dissecans are described as well. Furthermore the advantages of autologous against homologous bone-cartilage-transplants are discussed.

Ultrasound examination for the early determination of dysplasia and congenital dislocation of neonatal hips

Hip sonography enables an accurate and clinically relevant evaluation of hip maturation during the first days of human life. Experience has shown that an integration of hip sonography into neonatal screening programs is useful and necessary because clinical and even roentgenographic examination does not always establish a confirmed diagnosis of dysplasia.

[The hip joint of children. Clinical diagnosis in the infant]

The relative importance of clinical findings is age-related. While instability is the key criterion in the neonatal phase, inhibition of abduction is of decisive importance as of the second month of life. However, the correct diagnosis can only be reached on the basis of a synopsis of all historical and clinical signs. Such signs are not sufficient to rule out disorders of hip maturation or to detect them beyond doubt, and above all early. Early diagnosis can only be improved by general sonographic screening of newborns. Clinical examination continues to be indispensable for differential diagnosis and for the introduction and performance of therapy tailored to the individual case.

Ultrasonography of achilles tendons in primary hypercholesterolemia. Comparison with computed tomography

Tendon xanthoma are a hallmark of familial hypercholesterolemia and are among its earliest clinical manifestations. Achilles tendon size, advanced to a generally accepted marker, is virtually specific for the disease and easily accessible for measurement. Hypercholesterolemic patients with coronary heart disease have been reported to have larger diameters of the Achilles tendons than patients without coronary problems. Furthermore, Achilles tendon xanthomas have been shown to regress with treatment of the lipid disorder. Mainly radiological procedures were applied in the past to evaluate the diameters of the Achilles tendon but their use is limited by radiation protection. We have used real-time ultrasonography to evaluate the Achilles tendons of 38 patients with primary hypercholesterolemia and 32 normocholesterolemic controls. The anterior posterior diameter in the patients was 13.4 +/- 5.9 mm (range 6-20 mm) and 5.7 +/- 0.7 mm (range 5-8 mm) in the control group. In 8 patients with newly diagnosed and previously untreated hypercholesterolemia the thickness correlated highly with their age. The Achilles tendons in about half of the patients (n = 21) showed a homogeneous thickening, whereas the others revealed an inhomogeneous thickening indicating the presence of circumscribed xanthoma. Upon comparison of the ultrasonographic procedure with an established method (computed tomography) in 18 patients and 8 normal volunteers a highly significant correlation (r = 0.96) proved the validity of the sonography. We show that real time ultrasonography is a valid procedure to assess Achilles tendon diameters in patients with primary hypercholesterolemia. It can be applied frequently and may be useful to follow xanthoma regression during lipid lowering treatment.

[Ultrasonic diagnosis of soft tissue tumors]

Ultrasonography is relatively simple to manage, has no known risks to be patient, and is quickly available, all of which makes it a valuable tool, among the imaging techniques, in the primary diagnosis and initial work-up of soft-tissue tumors. Ultrasonography can reveal the extent of a tumor. Preoperative examination of a tumor in any number of planes gives the clinician a spatial idea of its size. Additionally, the internal architecture and structure of the tumor can be assessed. Sonography can distinguish whether lesions are predominantly cystic, solid, or more complex. Calcium deposits or foreign bodies can be demonstrated in some cases. It is difficult to delineate the margins of a tumor by sonography. Expanding and displacing tumor growth or infiltration cannot be diagnosed with certainty. Perifocal edema can make tumors appear larger than they in fact are. Ab type-specific differences of soft tissue tumors are demonstrable by sonography. Tissue differentiation is not possible.

[Sonographic control of the clinical course of hip development disorders]

The ultrasonic examination is a valuable completation of the diagnostical possibilities of recognizing very early disturbed maturation of hips. In our clinic the employment of ultrasonic methods has proved extremely valuable in more than 1500 hips of newborns. The value of sonographic examinations of hips is represented by means of follow-up's.

[Follow-up results after lumbar renucleotomy]

This is a report on the results of reoperations of lumbar disc prolapses. Ninety-seven operations in ninety-one patients were performed for recurrence of a disc prolapse. The recurrence rate of the cases reviewed was 6.5 per cent. More than 80 per cent of the ninety-one patients who had answered a questionnaire were satisfied with the result of reoperation. About 66 per cent of the patients were able to pursue their former occupation, 20 per cent required vocational rehabilitation, in about 20 per cent of the cases disablement was acknowledged.

[Lumbar nucleotomy in children and adolescents]

Among 2987 patients operated on for lumbar disc protrusion between 1969 and 1980 twenty-six adolescents up to the age of twenty years have been found. This corresponds to 0.87 per cent. The average age at operation was 17.3 years, the youngest patient had twelve years. Twenty-one patients have been followed up for one to twelve years. The postoperative results as well as special details as to etiology and symptoms are discussed.

[Osteochondrosis dissecans of the patella (author's transl)]

This is a report on seven cases of osteochondritis dissecans patellae in which the diagnosis was made and operative treatment was performed. The clinical and roentgenological follow-up after an average of fourteen months shows that generally good results have been achieved by the fixation of the osteochondral fragments by cortical match stick grafts.

Experiments and calculations concerning a thermal enzyme probe

A simple device capable of measuring almost any reactant in an enzyme-catalyzed reaction is created when an enzyme is immobilized onto one thermal sensor of a differential thermometer. Experiments are described in which two thermistors, one bare and one coated with immobilized enzyme, are immersed in a well-stirred solution. The response of this device to increases in glucose-ATP concentration was observed using hexokinase (ATP:D-hexose 6-phosphotransferase, EC 2.7.1.1), and to increases in glucose concentration using glucose oxidase (beta-D-glucose:oxygen 1-oxidoreductase, EC 1.1.3.4). A simple model is presented whose predictions are in reasonable agreement with the experimental results.