The ineffectiveness of a non-weight based heparin regimen in achieving therapeutic activated partial thromboplastin time (aPTT) in acute coronary syndrome

Evaluating Unfractionated Heparin Fixed Dosing Protocol and Establishing an Institutional Therapeutic Range for UFH in Hospital Setting in Jordan

This study was conducted to evaluate current unfractionated heparin (UFH) dosing regimen and establish an institutional therapeutic range for UFH in a public hospital in Jordan. In the first part, medical records of 241 patients who received UFH were reviewed retrospectively. In the second part, blood samples were withdrawn from 60 patients on UFH, and activated partial thromboplastin time and anti-Xa assay were measured. Most activated partial thromboplastin time readings were not therapeutic (91.4%) and recurrence of thrombosis was reported in 35.3% of patients. In the second part, therapeutic activated partial thromboplastin time range corresponding to the UFH concentration of 0.3 to 0.7 anti-factor Xa unit/mL was 56 to 95 seconds, which corresponds to an activated partial thromboplastin time range of 1.5 of 2.8 times the mean control value. The traditional activated partial thromboplastin time range ratio of 1.5 to 2.5 times the control value can result in subtherapeutic UFH levels.

Assessment of four different methods in subcutaneous heparin applications with regard to causing bruise and pain

Subcutaneous administration of the anticoagulant heparin sodium is a frequently performed nursing intervention. Subcutaneous heparin injection often causes problems such as bruise, pain, induration, and hematoma at the injection site. Bruising that result from heparin injections may lead to anxiety, disruption of body image, the rejection of the treatment in patients, and the reduction of the reliance of patient to nurse. The purpose of this study was to determine and compare the effects of four different injection technique pain and on bruising associated with subcutaneous heparin. The research involved ninety-five patients. Each subject received four injections by the same investigator using four different techniques. Site bruising was measured at forty-eight and seventy-two after each injection. The bruising size was measured using milimetric transparent palyethylene wrap and the verbal pain scale. There was significant difference in the incidence or size of bruises and pain perception the subject among techniques. Results of the study show that use of air lock technique without aspiration and two-minute cold application to the area of injection with methods reduce bruise and pain.

A novel ovine ex vivo arteriovenous shunt model to test vascular implantability

The major objective of successful development of tissue-engineered vascular grafts is long-term in vivo patency. Optimization of matrix, cell source, surface modifications, and physical preconditioning are all elements of attaining a compatible, durable, and functional vascular construct. In vitro model systems are inadequate to test elements of thrombogenicity and vascular dynamic functional properties while in vivo implantation is complicated, labor-intensive, and cost-ineffective. We proposed an ex vivo ovine arteriovenous shunt model in which we can test the patency and physical properties of vascular grafts under physiologic conditions. The pressure, flow rate, and vascular diameter were monitored in real-time in order to evaluate the pulse wave velocity, augmentation index, and dynamic elastic modulus, all indicators of graft stiffness. Carotid arteries, jugular veins, and small intestinal submucosa-based grafts were tested. SIS grafts demonstrated physical properties between those of carotid arteries and jugular veins. Anticoagulation properties of grafts were assessed via scanning electron microscopy imaging, en face immunostaining, and histology. Luminal seeding with endothelial cells greatly decreased the attachment of thrombotic components. This model is also suture free, allowing for multiple samples to be stably processed within one animal. This tunable (pressure, flow, shear) ex vivo shunt model can be used to optimize the implantability and long-term patency of tissue-engineered vascular constructs.

Heparin dosing and therapeutic activated partial thromboplastin times (aPTT) in acute coronary syndrome (ACS)

This study assessed the current practices of heparin dosing and determined the extent of therapeutic activated partial thromboplastin times (aPTT) achieved, utilising a standard heparin nomogram in the coronary care unit and step-down cardiac ward of a health care facility in South Australia. The study also examined the effect of actual body weight (ABW), body mass index (BMI), smoking, concomitant intravenous glycerine trinitrate, age, gender and creatinine levels, individually, on the time taken to attain a therapeutic aPTT in acute coronary syndrome (ACS) patients receiving a heparin infusion. A retrospective correlational research design was utilised to include the collection of quantitative data from 66 men and women of all ages and background consecutively admitted into the coronary care unit and the step-down cardiac ward and receiving a continuous heparin infusion. The quantitative data included demographic details plus all information regarding treatment and results of heparin therapy from the patients' medical records. Descriptive analysis of the data revealed 32% of the participants attained a therapeutic level with the first aPTT taken and that, successively, 35% and 45% of the participants attained a therapeutic level with the second and third aPTT taken. The majority of participants were found to be outside of the therapeutic range at any one time during the study. A generalised linear model (log-binomial model) applied to the data revealed that increased ABW (p=0.002), creatinine levels (p=0.033) and, in particular, BMI (p=0.000) were significant risk factors that contributed to the failure of participants attaining a therapeutic aPTT level. Age (p=0.668), gender (p=0.623), smoking (p=0.993) and the use of concomitant intravenous glycerine trinitrate (p=0.897) did not have a significant effect on the time to reach a therapeutic aPTT. The results provide noteworthy information for the re-evaluation of the use of the standard heparin nomogram. A robust randomised clinical trial is required to further examine BMI as the best predictor for heparin requirements in ACS patients receiving a heparin infusion.

Utility of a weight-based heparin nomogram for patients with acute coronary syndromes

BACKGROUND

Unfractionated heparin has been pivotal in the management of acute coronary syndromes (ACS), and continues to be used widely despite the emerging role of low molecular weight heparins (LMWH). The apparent superiority of LMWH over unfractionated heparin may, at least partially, reside in its more predictable achievement of therapeutic effect, with high rates of non-therapeutic activated partial thromboplastin time (APTT) results being observed in the intravenous heparin treatment groups.

AIM

To evaluate the impact of introduction of a weight-based heparin nomogram developed for use in patients with ACS on frequency of 'therapeutic' APTT results.

METHODS

The effectiveness of an existing non-weight-based heparin nomogram in achieving a therapeutic APTT was compared sequentially with that of a weight-based heparin nomogram in 89 and 84 consecutive patients admitted with a diagnosis of ACS.

RESULTS

Patients in whom heparin dosage adjustment was weight based rapidly achieved therapeutic APTT. The median time to achieve an APTT within the target range was 8.75 h in the weight-based group versus >24 h in the non-weight-based group. Utilization of a weight-based nomogram was associated with markedly increased proportions of readings within the therapeutic APTT range at 6 h and at 24 h (51%vs. 26% and 72%vs. 36%, respectively).

CONCLUSIONS

The current study confirms the marked superiority of the weight-based heparin regimen for treatment of patients with ACS. The nomogram dramatically facilitated the attainment of therapeutic APTT, and may represent the optimal method for titration of heparin dosage to individual heparin requirements in patients with ACS.

Effects of injection duration on site-pain intensity and bruising associated with subcutaneous heparin

AIM

The research evaluated two subcutaneous heparin injection techniques to determine the effects of different injection duration (10- and 30-seconds) on site-pain intensity and bruising.

BACKGROUND

The research was instigated because nurses and patients in the hospital under investigation reported a high incidence of site-pain and bruising associated with subcutaneous heparin therapy. This research was conducted over a period of 7 months between September 1998 and April 1999. The Ethic Committees of the University and the hospital approved the research.

METHODS

The research used a within-subjects, quasiexperiment, which would yield more convincing causal inferences, owing to the assumption that pain perception and physiological factors affecting coagulation varied less in the same subject than in two comparable subjects. The research involved 34 stroke patients receiving low-molecular weight heparin. For each subject, one of the two injection techniques was used as the first injection and 12 hours later the other injection technique as the second injection. Subjects rated the level of perceived site-pain intensity using the vertical visual analogue scale (VAS). Injection-site bruising were measured at 48 and 60 hours after each injection. Digital planimetry was used to measure the surface-area of bruise tracings. The final data set for analysis consisted of 68 VAS pain scores and 136 bruise sizes. As normality of the data could not met after transformations, Wilcoxon Signed-Rank tests were used to determine the effects caused by injection duration on site-pain and bruise size. The level of significance was determined at P < 0.05.

RESULTS

Results indicated that the 30-second duration injection technique resulted in significantly less intense site-pain and fewer and smaller bruises.

CONCLUSIONS

It was concluded that administering a subcutaneous heparin injection over longer duration reduces injection site-pain and bruising. However, the convenience, relatively small sample may limit the generalisability of the research findings.