Adaptation and validation of an adverse drug reaction preventability score for bleeding due to vitamin K antagonists.

Although drug therapy is inherently associated with the risk of adverse drug reactions (ADRs), some of these events are preventable. The estimated proportion of preventable ADRs varies from one study or clinical context to another. Bleeding caused by antithrombotic agents (and particularly vitamin K antagonists, VKAs) constitutes one of the most frequent causes of ADR-related hospitalization.Hence, the objective of the present study was to adapt and validate an ADR preventability score for bleeding due to VKAs and evaluate the preventability of bleeding in 906 consecutive hospitalized, VKA-treated adult patients with a risk of major bleeding (defined as an international normalized ratio ≥5) over a 2-year period. A specific preventability scale for VKA-associated bleeding was developed by adapting a published tool.Overall, 241 of the 906 patients in the study experienced at least 1 VKA-associated bleeding event. The scale's reliability was tested by 2 different evaluators. The inter-rater reliability (evaluated by calculation of Cohen's kappa) ranged from "good" to "excellent." Lastly, the validated scale was used to assess the preventability of the VKA-associated bleeding. We estimated that bleeding was preventable or potentially preventable in 109 of the 241 affected patients (45.2%).We have developed a useful, reliable tool for evaluating the preventability of VKA-associated bleeding. Application of the scale in a prospective study revealed that a high proportion of VKA-associated bleeding events in hospitalized, at-risk adult patients were preventable or potentially preventable.

Extrapyramidal adverse drug reactions associated with trimetazidine: a series of 21 cases.

Over the last few years, a number of cases of extrapyramidal disorders associated with trimetazidine (TMZ) use has been reported. Here, we report on a series of 21 cases. All but one of the patients (mean age 74) had been taking TMZ for several years. The indication for prescription of TMZ could not be identified in seven cases. The TMZ-associated adverse drug reactions were typical parkinsonism (akinesia and/or rigidity and/or rest tremor) in 17 cases, gait disorders in three cases (one with orthostatic tremor), and restless leg syndrome in one case. Discontinuation of TMZ led to complete disappearance of the symptoms in 16 cases and a significant reduction in the five other patients. TMZ has the same piperazine core as the dopamine antagonists flunarizine and cinnarizine (both of which have been reported to induce extrapyramidal symptoms). Hence, striatal D2 receptor blockade could result in the onset or the worsening of extrapyramidal disorders. Even though this adverse drug reaction is now listed in TMZ's Summary of Product Characteristics (because of the initial reports), the risk remains poorly known by clinicians. There is a need to raise awareness of this phenomenon and to reassess TMZ 's risk-benefit ration, especially in the elderly.

[Quantification of the part allocated to the preventability of vitamin K antagonists therapy bleeding events]. / Evaluation de l'évitabilité des accidents hémorragiques sous antivitamines K.

A prospective cohort of patients with a high INR (>or=5) and being treated by vitamin K antagonists (VKA) was assessed in the Amiens University Hospital. One of the purposes of the study was to assess the preventability of the haemorrhages due to VKA. The preventability concept is not very used in France. Identifying the preventability part of a side effect of a drug needs an adapted and reliable tool. Although different methods of assessment of preventability have been developed, none of them is unquestionable. For the needs of our study, we built a scale of measure adapted from a scale of preventability already published by defining more accurately some items and by reducing the subjective part of the interpretation. We were able to confirm the relevance of our revised scale by testing it by two experts. After consensus on the conflicting data, two thirds of the severe bleedings were considered as "potentially or totally preventable". These data are in agreement with published data. Indeed the data found in the literature are concordant to consider that an important part of VKA bleedings events can be prevented by a better management of the treatment.

Monitoring of respiratory variations of aortic blood flow velocity using esophageal Doppler.

OBJECTIVE: The purpose of this study was to determine whether monitoring of respiratory changes in aortic blood flow velocity, recorded by esophageal Doppler, could be used to detect changes in volume depletion. DESIGN: Animal study. ANIMALS AND INTERVENTIONS: After general anesthesia and tracheotomy, ten New Zealand female rabbits, weighing 4-4.5 kg were studied under mechanical ventilation at a fixed tidal volume; during this time 5-ml blood samples were withdrawn (in increments up to a total of 30 ml) and then retransfused. MEASUREMENTS AND RESULTS: At each step, systolic (SBP), diastolic (DBP), pulse (PP) pressures and maximum descending aortic blood flow (V) were recorded. Respiratory changes of V (DeltaV), SBP (DeltaSBP) and PP (DeltaPP) were calculated as the difference of maximal and minimal values divided by their respective means and expressed as a percentage. The amount of blood withdrawn correlated negatively with SBP, DBP, PP and V and positively with DeltaSBP, DeltaPP and DeltaV. Among these parameters, DeltaV correlated best with the amount of blood withdrawn ( r=0.89, p<0.001) and it was the most accurate index of volume depletion. CONCLUSION: Monitoring of the respiratory variation in V, calculated by esophageal Doppler technique, seems to be a highly accurate index of blood volume depletion and restitution.

Respiratory variations of aortic VTI: a new index of hypovolemia and fluid responsiveness.

In 12 mechanically ventilated and anesthetized rabbits, we investigated whether the magnitude of respiratory changes in the aortic velocity time integral (VTI(Ao)), recorded by transthoracic echocardiography (TTE) during a stepwise blood withdrawal and restitution, could be used as a reliable indicator of volume depletion and responsiveness. At each step, left and right ventricular dimensions and the aortic diameter and VTI(Ao) were recorded to calculate stroke volume (SV) and cardiac output (CO). Respiratory changes of VTI(Ao) (maximal - minimal values divided by their respective means) were calculated. The amount of blood withdrawal correlated negatively with left and right ventricular diastolic diameters, VTI(Ao), SV, and CO and correlated directly with respiratory changes of VTI(Ao). Respiratory VTI(Ao) variations (but not other parameters) at the last blood withdrawal step was also correlated with changes in SV after blood restitution (r = 0.83, P < 0.001). In conclusion, respiratory variations in VTI(Ao) using TTE appear to be a sensitive index of blood volume depletion and restitution. This dynamic parameter predicted fluid responsiveness more reliably than static markers of cardiac preload.