Platelet gel in the treatment of cutaneous ulcers: the experience of the Immunohaematology and Transfusion Centre of Parma

Background

Platelet gel is being ever more frequently used to promote healing of cutaneous ulcers. However, the factors that determine the often variable clinical outcome of this procedure are still incompletely understood.

Aims

The aims of this study were to demonstrate that platelet gel, even when obtained under strictly controlled conditions, produces highly variable outcomes in patients with cutaneous ulcers and to propose a method for in vitro standardisation of the biological properties of platelet gel.

Material and methods.

Patients were enrolled on the basis of a pre-defined protocol. Platelet concentrate was produced with standard methods, with a variability in platelet count among the different samples of less than 10%. The platelet gel for clinical use was obtained, under strictly standardized conditions, by adding thrombin and calcium gluconate to the concentrates. For in vitro studies, platelet gel, obtained from platelet-rich plasma from four donors, was frozen and thawed twice so as to increase gel contraction. The supernatant was used to modify cell proliferation, protein synthesis, and the expression of selected genes in cultures of human diploid fibroblasts.

Results

Seventeen patients (aged 44–78 years) with ulcers (4 diabetic, 11 vascular, 1 post-traumatic, 1 decubitus) were treated with platelet gel (4 autologous, 13 homologous). Complete re-epithelialisation of four ulcers (1 diabetic, 1 post-traumatic, 2 vascular) was obtained after applications of platelet gel (2 autologous, 2 homologous); in 11 other cases there was a greater than 50% reduction in the size of the ulcer. Two patients had no benefit. The supernatant of the platelet gel was able to promote dose-dependent proliferation and changes in gene expression as well as in metabolic activities related to protein synthesis.

Conclusions

Although the use of platelet gel in the treatment of cutaneous ulcers is increasing, and conditions for its production are better standardised, very considerable variability of clinical outcomes is still observed, even within single centres, suggesting that there are differences in biological properties of platelet concentrates from individual patients which cannot be readily controlled with current techniques. The biological effects of the platelet gel supernatant described in this article may provide the basis for a simple biological validation of platelet preparations before their clinical use, so as to reduce this potentially important source of variability.     

White blood cell count, sex and age are major determinants of heterogeneity of platelet indices in an adult general population: results from the MOLI-SANI project

Background

The understanding of non-genetic regulation of platelet indices - platelet count, plateletcrit, mean platelet volume, and platelet distribution width - is limited. The association of these platelet indices with a number of biochemical, environmental and clinical variables was studied in a large cohort of the general population.

Design and Methods

Men and women (n=18,097, 52% women, 56±12 years) were randomly recruited from various villages in Molise (Italy) in the framework of the population-based cohort study “Moli-sani”. Hemochromocytometric analyses were performed using an automatic analyzer (Beckman Coulter, IL, Milan, Italy). Associations of platelet indices with dependent variables were investigated by multivariable linear regression analysis.

Results

Full models including age, sex, body mass index, blood pressure, smoking, menopause, white and red blood cell counts, mean corpuscular volume, D-dimers, C-reactive protein, high-density lipoproteins, low-density lipoproteins, triglycerides, glucose, and drug use explained 16%, 21%, 1.9% and 4.7% of platelet count, plateletcrit, mean platelet volume and platelet distribution width variability, respectively; variables that appeared to be most strongly associated were white blood cell count, age, and sex. Platelet count, mean platelet volume and plateletcrit were positively associated with white blood cell count, while platelet distribution width was negatively associated with white blood cell count. Platelet count and plateletcrit were also positively associated with C-reactive protein and D-dimers (P<0.0001).Each of the other variables, although associated with platelet indices in a statistically significant manner, only explained less than 0.5% of their variability.Platelet indices varied across Molise villages, independently of any other platelet count determinant or characteristics of the villages.

Conclusions

The association of platelet indices with white blood cell count, C-reactive protein and D-dimers in a general population underline the relation between platelets and inflammation.     

Inconsistency of different methods for assessing ex vivo platelet function: relevance for the detection of aspirin resistance

Background

Assays to evaluate platelet function are often interchangeably used to assess “resistance” to aspirin. We compared different platelet function assays in patients treated or untreated with aspirin.

Design and Methods

Platelet function was evaluated in 162 subjects, 85 of whom were not being treated with any antiplatelet drug and 77 of whom were receiving chronic therapy with low-dose aspirin. Platelet Function Analyzer collagen/ADP- and collagen/epinephrine closure times, as well as light transmittance aggregometry in response to ADP, collagen and arachidonic acid (this last in 47 aspirin-treated patients) were determined. In 43 aspirin-treated patients, serum thromboxane B₂ levels were also measured.

Results

In untreated patients, collagen/ADP- and collagen/epinephrine-closure times were correlated with each other (r=0.5, P=0.0001), but did not correlate with ADP- or collagen-induced aggregation. In patients treated with aspirin, collagen/ADP-closure time values were not different from those in untreated patients, while the collagen/epinephrine-closure time was prolonged. ADP-induced aggregation was unaffected by aspirin, while collagen-induced aggregation was reduced. Arachidonic acid-induced aggregation was almost completely suppressed (% maximum light transmittance aggregometry=5±13%). There was, however, no correlation between the various platelet function tests. Serum thromboxane B₂, an index of platelet cyclooxygenase-1 activity, was almost completely suppressed (down to 8±17 ng/mL) in treated patients, and was not correlated with arachidonic acid-, ADP- and collagen-induced aggregation or with collagen/ADP-closure time, but was inversely correlated with collagen/epinephrine-closure time.

Conclusions

There is a high heterogeneity of results of tests evaluating inhibition of platelet function by aspirin, and the results of functional tests do not match biochemical measurement of cyclooxygenase-1 activity. Extreme caution should, therefore, be used in defining “resistance” to aspirin on the basis of the results of these tests.     

Platelet gel-released supernatant modulates the angiogenic capability of human endothelial cells

Background

Platelet gel is used to facilitate wound healing in virtue of the growth factors released from activated platelets at the site of lesion, but little is known about the specific mechanisms underlying cellular repair.

Aims

To evaluate, in vitro, cellular effects of different concentrations of platelet gel -released supernatant on endothelial cells.

Material and methods

Platelet concentrate was produced at the Service of Immunohaematology and Transfusion of San Salvatore Hospital of L’Aquila, using multiple bags. Platelet gel was obtained by adding thrombin and calcium gluconate to the concentrates and then centrifuging to recover the supernatant.Human umbilical vein endothelial cells were isolated from umbilical cord veins and grown in appropriate conditions. To study their viability, cells were treated with different concentrations of supernatant and XTT assays were performed on the 3 days following treatment. Endothelial cell motility and invasiveness were assayed using modified Boyden chambers with filters coated with 0.1% gelatin (for the motility test) or with a thick layer of the reconstituted basement membrane Matrigel (for the invasion test). The supernatant, added at various concentrations to the lower compartment of the chamber, was used as an attractant. Umbilical cells were added to the upper compartment of the chamber. After 4 hours (for the motility test) or 6 hours (for the invasion test), filters were stained and the migrated cells in five high-power fields were counted.

Results

When used at specific concentrations, platelet gel-released supernatant is able to induce proliferation and to stimulate motility and invasiveness of endothelial human cells. Higher concentrations induce a reversion of the stimulatory processes.

Conclusions

There is a large body of evidence indicating that platelets and their derivatives have the potential for a substantial therapeutic role in tissue regeneration. The results of this in vitro study highlight the need for an in-depth analysis of technical protocols for the most appropriate and effective use of platelet gel for in vivo applications.     

Platelet gel for the treatment of traumatic loss of finger substance

Background

Autologous or allogenic platelet gel is a blood component that exploits the effects of the cytokines contained in platelet α granules to stimulate repair processes. The properties of platelet gel were first tested on chronic ulcers to accelerate healing and later in orthopaedic, dental, vascular and cardiothoracic surgery.In our centre, we have been using platelet gel for 5 years, first for surgical patients with difficult wounds, then for orthopaedic patients undergoing osteosynthesis surgery and patients with ulcers not responding to traditional therapies. Subsequently we decided to extend the use of platelet gel also to amputations or traumatic loss of tissue of fingers.

Materials and methods

In this article we present the results obtained over 5 years concerning 115 patients with finger amputations or wounds treated with platelet gel in our Service of Transfusion Medicine. Platelets were obtained fom allogeneic buffy coats (10 mL) and the gel was produced by adding thrombin to concentrated platelets.The decision to use homologous platelet gel was based on its limited cost, ease of preparation, almost unlimited availability, the fact that the number of platelets that can be collected is much higher than the therapeutic range and so able to replace the losses due to secondary medication, and last, but not least, it causes no discomfort to patients. The safety of the product was ensured by virology tests including molecular biology studies.

Results

The recovery of soft tissue in all patients ranged from 80 to 100%; the median time for this recovery was 3 weeks (range, 10 days - 6 weeks). Approximately 60% of the patients complained of local hypoaesthesia for some weeks; 30% of the patients developed hyperaesthesia, which resolved completely within 6–8 weeks from starting treatment. Loss of bone tissue represented an obstacle to total tissue recovery, but the aesthetic results were satisfactory in nearly all cases.

Conclusion

All patients showed good compliance, both because of the low frequency of medications (at most, twice a week) and because of the painless platelet gel applications. The only negative aspect was abnormal nail growth in a case of distal partial amputation of a finger.In conclusion, we believe that platelet gel can be very useful in patients with traumatic or surgical loss of finger tissue, since it can resolve critical situations thus avoiding amputation of residual tissue and compromised joint function.     

The Mirasol? Pathogen Reduction Technology system and quality of platelets stored in platelet additive solution

Background

The Mirasol Pathogen Reduction Technology system for platelets and plasma uses riboflavin and UV light to introduce irreparable lesions into nucleic acids thereby inhibiting pathogen and white blood cell replication and reducing the load of infectious pathogens. The aim of the present study was to evaluate low plasma buffy coat platelet concentrates obtained from the OrbiSac System and to examine the effects on the development of platelet storage lesion during storage in platelet additive solution.

Material and Methods

Twenty buffy coat platelet concentrates were generated by pooling five individual units using the OrbiSac System. Riboflavin was added during the final pooling step, and the units were exposed to UV light. The bag was removed after the target energy of 6.24 J/mL had been delivered and 150 mL of platelet additive solution were added prior to storage. Platelet quality was assessed by pH, swirl, CD62P expression, lactate dehydrogenase, lactate production and glucose consumption rates over 7 days of storage.

Results

Buffy coat platelet concentrates generated on the OrbiSac contained an average 3.5 ± 0.6 x 10¹¹ platelets at a concentration of 2976± 406 x 10⁶/mL. After addition of 150 mL platelet additive solution the storage concentration was 1043 ± 148x 10⁶/mL. Values obtained for pH, lactate production and glucose consumption rates were all within the limits of previously established correlations between in vitro cell quality and in vivo performance of Pathogen Reduction Technology-treated platelets in plasma.

Discussion

In vitro studies show that OrbiSac-derived platelets treated with the Mirasol Pathogen Reduction Technology system preserve adequate function, which would indicate acceptable in vitro viability.     

Therapeutic efficacy of different types of platelet concentrates in thrombocytopenic patients

Background

Platelet Rich Plasma-Platelet concentrate (PRP-PC), Buffy Coat poor-platelet concentrate (BCPC), and Apheresis — PC were prepared and their therapeutic efficacy were assessed in thrombocytopenic patients.

Study design and methods

PRP-PC and BC-PC were prepared from whole blood and Apheresis-PC by automated cell separator. The post transfusion efficacy of transfused platelets was assessed at 1 hour and 20 hours by corrected count increment (CCI) and percentage recovery (PR).

Results

A total of 60 patients’ (20 each for PRP-PC, BC-PC and Apheresis-PC) were enrolled in this study. Forty one patients received therapeutic and nineteen received prophylactic transfusion support. Patients with aplastic anemia 43% (25/60) and acute leukemia 38% (23/60) formed a majority of study population. Platelet dosage of patients’ received PRP-PC, BC-PC and apheresis-PC were 2.4±0.82 × 1011 (mean±SD), 2.2±0.83 × 1011 (mean±SD) and 4.14±1.82 × 1011 (mean±SD) and ranged from 1.16–4.11 × 1011, 1.04−4.20 × 1011 and 1.22−8.90 × 1011 respectively. There was significantly increase in inter-transfusion interval with Apheresis-PC than with PRP-PC and BC-PC recipients [(Mean±S.D.), 4.7±1.33 days Vs 2.7±0.82 days Vs 2.5±0.7 days respectively] (p < 0.05).

Conclusions

Patients transfused with apheresis-PC had received higher platelet dosage than PRP-PC and BC-PC and this difference was statistically significant (p < 0.001). The post transfusion platelet counts and increments at 1 hour and 20 hours were significantly higher with apheresis-PC than PRP-PC and BC-PC (p < 0.001). However, the corrected count increment (CCI) and percentage recovery (PR) in all three groups were comparable. There was significantly increase in inter-transfusion interval with apheresis-PC than PRPPC and BC-PC (p < 0.05).     

Storage of platelets: effects associated with high platelet content in platelet storage containers

Background

A major problem associated with platelet storage containers is that some platelet units show a dramatic fall in pH, especially above certain platelet contents. The aim of this study was a detailed investigation of the different in vitro effects occurring when the maximum storage capacity of a platelet container is exceeded as compared to normal storage.

Materials and methods

Buffy coats were combined in large-volume containers to create primary pools to be split into two equal aliquots for the preparation of platelets (450–520×10⁹ platelets/unit) in SSP+ for 7-day storage in two containers (test and reference) with different platelet storage capacity (n=8).

Results

Exceeding the maximum storage capacity of the test platelet storage container resulted in immediate negative effects on platelet metabolism and energy supply, but also delayed effects on platelet function, activation and disintegration.

Conclusion

Our study gives a very clear indication of the effects in different phases associated with exceeding the maximum storage capacity of platelet containers but throw little additional light on the mechanism initiating those negative effects. The problem appears to be complex and further studies in different media using different storage containers will be needed to understand the mechanisms involved.     

Clopidogrel resistance response in patients with coronary artery disease and metabolic syndrome: the role of hyperglycemia and obesity

Background Despite the proven benefits of clopidogrel combined aspirin therapy for coronary artery disease (CAD), CAD patients with metabolic syndrome (MS) still tend to have coronary thrombotic events. We aimed to investigate the influence of metabolic risk factors on the efficacy of clopidogrel treatment in patients with CAD undergoing percutaneous coronary intervention (PCI). Methods Cohorts of 168 MS and 168 non-MS subjects with CAD identified by coronary angiography (CAG) were enrolled in our study. MS was defined by modified Adult Treatment Panel III criteria. All subjects had taken 100 mg aspirin and 75 mg clopidogrel daily for more than 1 month, and administered loading doses of 600 mg clopidogrel and 300 mg aspirin before PCI. Blood samples were taken 24 h after the loading doses of clopidogrel and aspirin. Platelet aggregation was measured using light transmittance aggregometry (LTA) and thrombelastography (TEG). Clopidogrel resistance was defined as more than 50% adenosine diphosphate (ADP) induced platelet aggregation as measured by TEG. Results Platelet aggregation inhibition rate by ADP was significantly lower in patients with MS as measured both by TEG (55% ± 31% vs. 68% ± 32%; P < 0.001) and LTA (29% ± 23% vs. 42% ± 29%; P < 0.001). In the multivariate analysis, elderly [OR (95% CI): 1.483 (1.047–6.248); P = 0.002], obesity [OR (95% CI): 3.608 (1.241–10.488); P = 0.018], high fasting plasma glucose level [OR (95% CI): 2.717 (1.176–6.277); P = 0.019] and hyperuricemia [OR (95% CI): 2.583 (1.095–6.094); P = 0.030] were all statistically risk factors for clopidogrel resistance. CAD patients with diabetes and obesity were more likely to have clopidogrel resistance than the CAD patients without diabetes and obesity [75% (61/81) vs. 43% (67/156); P < 0.001]. Conclusions CAD patients with MS appeared to have poorer antiplatelet response to clopidogrel compared to those without MS. Obesity, diabetes and hyperuricemia were all significantly associated with clopidogrel resistance.     

Up-regulation of platelet activation in hemophilia A

Background

Platelets are an underappreciated factor in the classification of the bleeding tendency of patients with hemophilia. In this cross-sectional study, we investigated platelet activation status and responsiveness in relation to residual factor VIII activity and, within the group with severe hemophilia (<1% residual factor VIII activity), to annual factor VIII consumption.

Design and Methods

Twenty-one patients with mild-moderate hemophilia A, 13 with severe hemophilia A and 21 healthy controls were studied. The basal level of platelet activation and platelet responsiveness to activation and inhibition were determined by the measurement of platelet P-selectin expression and soluble platelet activation markers.

Results

Patients with severe hemophilia A had a higher percentage of activated platelets at baseline (15.9%) when compared to patients with mild-moderate hemophilia A (8.2%, P=0.014) and controls (6.4%, P<0.001). Both patients with mild-moderate hemophilia A and those with severe hemophilia A had higher levels of the soluble platelet activation markers platelet factor 4 (1.4 and 1.8 pg/10⁶ platelets), CXCL7 (65.8 and 48.2 pg/10⁶ platelets) and RANTES (12.8 and 9.5 pg/10⁶ platelets), compared to controls (platelet factor 4: 0.3 pg/10⁶ platelets, P<0.001 and <0.001; CXCL7 20.0 pg/10⁶ platelets, P<0.001 and <0.001; RANTES 4.5 pg/10⁶ platelets, P<0.001 and =0.003, respectively). In support of these observations, we found clinical evidence that higher platelet P-selectin expression correlates with lower factor VIII consumption in patients with severe hemophilia (Spearman’s r −0.65, P=0.043).

Conclusions

This study indicates that platelets from patients with severe hemophilia A are in a pre-activated state and that this pre-activated state is associated with factor VIII consumption.     

Association Between Race, Depression, and Antiretroviral Therapy Adherence in a Low-Income Population with HIV Infection

Background

Racial disparities exist in many aspects of HIV/AIDS. Comorbid depression adds to the complexity of disease management. However, prior research does not clearly show an association between race and antiretroviral therapy (ART) adherence, or depression and adherence. It is also not known whether the co-existence of depression modifies any racial differences that may exist.

Objective

To examine racial differences in ART adherence and whether the presence of comorbid depression moderates these differences among Medicaid-enrolled HIV-infected patients.

Design

Retrospective cohort study.

Setting

Multi-state Medicaid database (Thomson Reuters MarketScan®).

Participants

Data for 7,034 HIV-infected patients with at least two months of antiretroviral drug claims between 2003 and 2007 were assessed.

Main Measures

Antiretroviral therapy adherence (90 % days covered) were measured for a 12-month period. The main independent variables of interest were race and depression. Other covariates included patient variables, clinical variables (comorbidity and disease severity), and therapy-related variables.

Key Results

In this study sample, over 66 % of patients were of black race, and almost 50 % experienced depression during the study period. A significantly higher portion of non-black patients were able to achieve optimal adherence (≥90 %) compared to black patients (38.6 % vs. 28.7 %, p < 0.001). In fact, black patients had nearly 30 % decreased odds of being optimally adherent to antiretroviral drugs compared to non-black patients (OR = 0.70, 95 % CI: 0.63–0.78), and was unchanged regard less of whether the patient had depression. Antidepressant treatment nearly doubled the odds of optimal ART adherence among patients with depression (OR = 1.92, 95 % CI: 1.12–3.29).

Conclusions

Black race was significantly associated with worse ART adherence, which was not modified by the presence of depression. Under-diagnosis and under-treatment of depression may hinder ART adherence among HIV-infected patients of all races.KEY WORDS: HIV, adherence, depression, race, Medicaid     

Blood Pressure Monitoring Technique Impacts Hypertension Treatment

BACKGROUND

In 2005 the American Heart Association (AHA) released updated recommendations for blood pressure (BP) monitoring in order to ensure accurate BP measurements.

OBJECTIVE

To determine if current methods of BP assessment in an ambulatory clinic result in significantly different BP measurements than those obtained by following the AHA recommendations and if these BP differences impact treatment decisions.

RESEARCH DESIGN

Randomized prospective analysis.

SETTING

University of New Mexico Hospital Adult Internal Medicine clinic.

PATIENTS

Forty adults with hypertension

METHODS

Patient BPs were measured using both the traditional triage method and the AHA-recommended method in cross-over fashion in random order. Two complete medical profile summaries were then constructed for each patient: one for each BP measurement obtained by each technique. These profiles were then reviewed by a panel of providers who provided hypothetical hypertension treatment recommendations.

RESULTS

Individual BP results varied greatly between the two methods. SBP readings differed by ≥5 mmHg in either direction for 68% of patients while 78% of patient’s DBP readings differed by ≥2 mmHg in either direction. Overall, 93% of patients had a BP difference of either ≥5 mmHg systolic or ≥2 mmHg diastolic. Five patients were determined to be at goal with the triage method, but were higher than their goal BP with the AHA method Significant differences were also seen in treatment recommendations for a given patient based on the differences seen between the two obtained BP readings. The number of patients with treatment variations between their two profiles ranged from 13% to 23% depending on the reviewing provider (p < 0.01 for all providers).

CONCLUSION

Inaccurate BP assessment is common and may impact hypertension treatment decisions.KEY WORDS: blood pressure measurement, hypertension     

Serum levels of homocysteine in mice with malignant tumours

BACKGROUND:

Oxygen radicals and malondialdehyde (MDA) are tumourigenic. Homocysteine generates oxygen radicals. The possibility exists that hyperhomocysteinemia is a risk factor for cancer.

OBJECTIVE:

To investigate if serum levels of homocysteine and MDA are elevated in mice with malignant tumours.

METHODS:

Levels of serum homocysteine and MDA were estimated in 22 control and 22 tumour-bearing Balb/c mice.

RESULTS:

Serum homocysteine levels in control and tumour-bearing mice were 3.01±0.26 μmol/L and 4.05±0.46 μmol/L, respectively. The serum levels of MDA were 6.23±0.72 nmol/mL and 11.60±1.72 nmol/mL, respectively, in control and tumour-bearing mice.

CONCLUSION:

These results suggest that cancer in mice is associated with an increase in serum levels of homocysteine and the lipid peroxidation product MDA. It is, however, not known if this rise in homocysteine and MDA is due to cancer or if this rise causes cancer.     

Randomized controlled trial of health maintenance reminders provided directly to patients through an electronic PHR

BACKGROUND

Provider and patient reminders can be effective in increasing rates of preventive screenings and vaccinations. However, the effect of patient-directed electronic reminders is understudied.

OBJECTIVE

To determine whether providing reminders directly to patients via an electronic Personal Health Record (PHR) improved adherence to care recommendations.

DESIGN

We conducted a cluster randomized trial without blinding from 2005 to 2007 at 11 primary care practices in the Partners HealthCare system.

PARTICIPANTS

A total of 21,533 patients with access to a PHR were invited to the study, and 3,979 (18.5%) consented to enroll.

INTERVENTIONS

Patients in the intervention arm received health maintenance (HM) reminders via a secure PHR “eJournal,” which allowed them to review and update HM and family history information. Patients in the active control arm received access to an eJournal that allowed them to input and review information related to medications, allergies and diabetes management.

MAIN MEASURES

The primary outcome measure was adherence to guideline-based care recommendations.

KEY RESULTS

Intention-to-treat analysis showed that patients in the intervention arm were significantly more likely to receive mammography (48.6% vs 29.5%, p = 0.006) and influenza vaccinations (22.0% vs 14.0%, p = 0.018). No significant improvement was observed in rates of other screenings. Although Pap smear completion rates were higher in the intervention arm (41.0% vs 10.4%, p < 0.001), this finding was no longer significant after excluding women’s health clinics. Additional on-treatment analysis showed significant increases in mammography (p = 0.019) and influenza vaccination (p = 0.015) for intervention arm patients who opened an eJournal compared to control arm patients, but no differences for any measure among patients who did not open an eJournal.

CONCLUSIONS

Providing patients with HM reminders via a PHR may be effective in improving some elements of preventive care.

Electronic supplementary material

The online version of this article (doi:10.1007/s11606-011-1859-6) contains supplementary material, which is available to authorized users.KEY WORDS: health maintenance reminders, personal health record, preventive care, clinical decision support, Patient Gateway     

General Practitioners’ Judgment of their Elderly Patients’ Cognitive Status

Background

General practitioners (GP) play an important role in detecting cognitive impairment among their patients.

Objectives

To explore factors associated with GPs’ judgment of their elderly patients’ cognitive status.

Design

Cross-sectional data from an observational cohort study (AgeCoDe study); General practice surgeries in six German metropolitan study centers; home visits by interviewers.

Participants

138 GPs, 3,181 patients (80.13 ± 3.61 years, 65.23% female).

Measurements

General practitioner questionnaire for each patient: familiarity with the patient, patient morbidity, judgment of cognitive status. Home visits by trained interviewers: sociodemographic and clinical data, psychometric test performance. Multivariate regression analysis was used to identify independent associations with the GPs’ judgment of “cognitively impaired” vs. “cognitively unimpaired.”

Results

Less familiar patients (adjusted odds ratio [aOR] 2.42, 95% CI 1.35–4.32, for poor vs. very high familiarity), less mobile patients (aOR 1.29, 95% CI 1.13–1.46), patients with impaired hearing (aOR 5.46, 95% CI 2.35–12.67 for serious vs. no problems), and patients with greater comorbidity (aOR 1.15, 95% CI 1.08–1.22) were more likely to be rated as “cognitively impaired” by their GPs.

Conclusions

The associations between GPs’ assessments of cognitive impairment and their familiarity with their patients and patients’ mobility, hearing, and morbidity provide important insights into how GPs make their judgments.KEY WORDS: general practice, cognition, dementia, clinical judgment     

Evaluation of platelet cross-matching in the management of patients refractory to platelet transfusions

Background

Cross-match-compatible platelets are used to support thrombocytopenic patients who are refractory to randomly selected platelets. However, few studies have addressed the efficacy of using this strategy for patients requiring intensive platelet transfusion therapy. The aim of this study was to determine the effectiveness of cross-match-compatible platelets in an unselected group of patients refractory to platelets from random donors.

Materials and methods

A total of 406 cross-match-compatible platelet components were administered to 40 evaluable patients who were refractory to random-donor platelets. A solid-phase red cell adherence method was used for platelet cross-matching. The corrected count increment was used to monitor the effectiveness of each platelet transfusion. Multivariate analysis was performed to detect whether any variables could predict the response to transfusion.

Results

Statistically significant improvements were found in the mean corrected count increment when comparing cross-match-compatible platelets with randomly selected and incompatible platelets (p<0.001 for each). Compatible platelet transfusions were associated with a good response in 72.9% of cases while incompatible platelets were associated with a poor response in 66.7% of transfusion events (p<0.001). In the presence of clinical factors or alloimmunisation, compatible platelets were associated with good responses in 67.9% and 28.0% respectively vs 100% and 93.3% in their absence (p=0.009, p<0.001). Multivariate analysis revealed that cross-matching and alloimmunisation were the strongest predictors of transfusion response at 1 hour, while ABO compatibility, type of units received, followed by alloimmunisation then clinical factors were predictors at 24 hours.

Discussion

Platelet cross-matching using the solid-phase red cell adherence technique is an effective and rapid first-line approach for the management of patients refractory to platelet transfusions.     

The Effects of Guided Care on the Perceived Quality of Health Care for Multi-morbid Older Persons: 18-Month Outcomes from a Cluster-Randomized Controlled Trial

BACKGROUND

The quality of health care for older Americans with chronic conditions is suboptimal.

OBJECTIVE

To evaluate the effects of “Guided Care” on patient-reported quality of chronic illness care.

DESIGN

Cluster-randomized controlled trial of Guided Care in 14 primary care teams.

PARTICIPANTS

Older patients of these teams were eligible to participate if, based on analysis of their recent insurance claims, they were at risk for incurring high health-care costs during the coming year. Small teams of physicians and their at-risk older patients were randomized to receive either Guided Care (GC) or usual care (UC).

INTERVENTION

“Guided Care” is designed to enhance the quality of health care by integrating a registered nurse, trained in chronic care, into a primary care practice to work with 2–5 physicians in providing comprehensive chronic care to 50–60 multi-morbid older patients.

MEASUREMENTS

Eighteen months after baseline, interviewers blinded to group assignment administered the Patient Assessment of Chronic Illness Care (PACIC) survey by telephone. Logistic and linear regression was used to evaluate the effect of the intervention on patient-reported quality of chronic illness care.

RESULTS

Of the 13,534 older patients screened, 2,391 (17.7%) were eligible to participate in the study, of which 904 (37.8%) gave informed consent and were cluster-randomized. After 18 months, 95.3% and 92.2% of the GC and UC recipients who remained alive and eligible completed interviews. Compared to UC recipients, GC recipients had twice greater odds of rating their chronic care highly (aOR = 2.13, 95% CI = 1.30–3.50, p = 0.003).

CONCLUSION

Guided Care improves self-reported quality of chronic health care for multi-morbid older persons.KEY WORDS: quality of care, chronic illness, older     

Fetal alloimmune thrombocytopenia and maternal intravenous immunoglobulin infusion

Background

Different therapeutic approaches have been used in fetal-neonatal alloimmune thrombocytopenia, but many centers administer immunoglobulin G infusions to the pregnant woman. We studied the effect of maternal antenatal immunoglobulin infusions on fetal platelet counts in pregnancies with fetal alloimmune thrombocytopenia.

Design and Methods

We retrospectively analyzed the clinical courses of fetuses with fetal alloimmune thrombocytopenia whose mothers were treated with immunoglobulin G infusions in a single center between 1999 and 2005. In a center-specific protocol, weekly maternal immunoglobulin G infusions were given to 25 pregnant women with previously affected neonates and four women with strong platelet antibodies, but no previous history of fetal alloimmune thrombocytopenia; before each infusion diagnostic fetal blood sampling was performed to determine fetal platelet counts and immunoglobulin G levels.

Results

There were 30 fetuses with fetal alloimmune thrombocytopenia, confirmed by initial fetal blood sampling showing fetal platelet counts between 4×10⁹/L and 130×10⁹/L and antibody-coated fetal platelets using a glycoprotein specific assay. Despite weekly antenatal maternal immunoglobulin G infusions fetal platelet counts did not change significantly. Maternal and fetal immunoglobulin G levels, measured before every infusion, increased significantly with the number of maternal immunoglobulin G infusions.

Conclusions

In this group of fetuses with fetal alloimmune thrombocytopenia no consistent increase of fetal platelets was achieved as a result of regular maternal immunoglobulin G infusions.     

Safety and diagnostic accuracy of stress cardiac magnetic resonance imaging vs exercise tolerance testing early after acute ST elevation myocardial infarction

Objective

To determine the safety and diagnostic accuracy of adenosine‐stress cardiac magnetic resonance (CMR) perfusion imaging early after acute ST elevation myocardial infarction (STEMI) compared with standard exercise tolerance testing (ETT).

Design and setting

Cross sectional observational study in a university teaching hospital.

Patients

35 patients admitted with first acute STEMI.

Interventions

All patients underwent a CMR imaging protocol which included rest and adenosine‐stress perfusion, viability, and cardiac functional assessment. All patients also had an ETT (modified Bruce protocol) and x ray coronary angiography.

Main outcome measures

Safety and diagnostic accuracy of adenosine‐stress perfusion CMR vs ETT early after STEMI in identifying patients with significant coronary stenosis (⩾70%) and the need for coronary revascularisation. Also, to determine if CMR can distinguish between ischaemia in the peri‐infarct zone and ischaemia in remote myocardium.

Results

CMR imaging was well tolerated (all patients completed the protocol) and no complications occurred. CMR was more sensitive (86% vs 48%, p = 0.0074) and more specific than ETT (100% vs 50%, p<0.0001) for detecting significant coronary stenosis, and more sensitive for predicting revascularisation (94% vs 56%, p = 0.039). Inducible ischaemia in the infarct related artery territory was seen in 21 of 35 patients and was associated with smaller infarct size and less transmurality of infarction.

Conclusions

Adenosine‐stress CMR imaging is safe early after acute STEMI and identifies patients with significant coronary stenosis more accurately than ETT.