Clinical effects of antiplatelet drugs and statins on D‐dimer levels

Background

Acute pulmonary embolism may be ruled out by combining nonhigh clinical probability and a normal D‐dimer level. Both antiplatelet drugs and HMG‐CoA reductase inhibitors (statins) have been associated with effects on thrombus formation, potentially influencing D‐dimer levels in this setting, leading to a higher rate of false‐negative tests. Therefore, we determined whether D‐dimer levels in patients with suspected pulmonary embolism are affected by concomitant use of antiplatelet drugs and/or statins and evaluated whether the effect of antiplatelet drugs or statins might affect diagnostic accuracy.

Materials and methods

We performed a posthoc analysis in the YEARS diagnostic study, comparing age‐ and sex‐adjusted D‐dimer levels among users of antiplatelet drugs, statins and nonusers. We then reclassified patients within the YEARS algorithm by developing a model in which we adjusted D‐dimer cut‐offs for statin use and evaluated diagnostic accuracy.

Results

We included 156 statins users, 147 antiplatelet drugs users and 726 nonusers of either drugs, all with suspected pulmonary embolism . Use of antiplatelet drugs did not have a significant effect, whereas statin use was associated with 15% decrease in D‐dimer levels (95% CI, ?28% to ?0.6%). An algorithm with lower D‐dimer thresholds in statin users yielded lower specificity (0.42 compared to 0.33) with no difference in false‐negative tests.

Conclusions

We conclude that use of statins but not of antiplatelet agents is associated with a modest decrease in D‐dimer levels. Adjusting D‐dimer cut‐offs for statin use did, however, not result in a safer diagnostic strategy in our cohort.

     

Direct videoscopic approach to the descending thoracic aorta for aortic arch endograft delivery: evaluation in a porcine model.

PURPOSE: To examine the feasibility of a direct videoscopic approach to the descending thoracic aorta for endograft delivery to the aortic arch. METHODS: A double purse-string suture was placed on the aorta of 3 pigs via a thoracoscopic approach. Subsequently, the aorta was cannulated in the center of the purse-string. A 22-F delivery catheter was advanced under fluoroscopic control over a guidewire via a trocar into the proximal aorta. After deployment of a tubular endograft, the catheter was withdrawn from the aorta while simultaneously tightening the purse-string suture, without aortic cross clamping. The outcome was evaluated by post implant angiography and autopsy results. RESULTS: The procedure was successfully completed in all animals, with a mean total procedure time of 126 minutes (range 118-137). Mean endograft implantation time from needle puncture to catheter extraction was 27 minutes (range 21-37). Hemostasis was obtained in all animals after withdrawal of the delivery catheter and tightening the purse-string suture. The mean blood loss was 143 mL (range 80-220). Autopsy proved all purse-string sutures to be adequately placed and all endografts deployed in the correct position. CONCLUSION: A direct videoscopic approach to the descending thoracic aorta proved a feasible technique for endograft delivery to the aortic arch in a porcine model.     

Frequency of major hemorrhage in patients treated with unfractionated intravenous heparin for deep venous thrombosis or pulmonary embolism: a study in routine clinical practice

BACKGROUND: The rate of major hemorrhage during the initial treatment with unfractionated heparin (UFH) in patients with deep venous thrombosis (DVT) and pulmonary embolism (PE) in routine clinical practice is understudied. In recent clinical trials an overall average of 3.8% was reported. However, the incidence of this complication in routine patient care might be higher owing to less strict patient selection and lack of standardization in the administration of heparin. We have determined major bleeding rates during heparin treatment for DVT or PE in routine practice and compared these rates with data from clinical trials. METHODS: Data on the occurrence of major hemorrhage were retrieved according to strict criteria from the records of patients who had received continuous intravenous UFH therapy to treat objectively documented DVT or PE in 3 hospitals. RESULTS: After exclusion of 29 patients because of lack of objective diagnosis of DVT or PE and 25 patients because of initial treatment with low-molecular-weight heparin, 424 consecutive patients were available for detailed analysis. Among them, 17 patients (4.0%; 95% confidence interval, 2.1%-5.9%) experienced major hemorrhage during UFH treatment, which in most patients occurred at the end of planned heparin therapy; one of the hemorrhages was fatal. Six patients (1.4%; 95% confidence interval, 0.3%-2.5%) developed clinically suspected recurrent venous thromboembolism (fatal in 1 case) during UFH treatment or within 7 days' cessation. CONCLUSIONS: Administration of continuous intravenous UFH in patients with DVT or PE in routine clinical practice leads to a major bleeding rate of 4.0%. This rate is comparable to the rate of major bleeding in patients who received UFH in clinical trials. Our findings are relevant to the discussion of major bleeding rates in patients with DVT and PE treated in daily clinical practice with subcutaneous low-molecular-weight heparin and newer antithrombotic drugs.     

Susceptibility-Weighted Imaging in Pediatric Arterial Ischemic Stroke: A Valuable Alternative for the Noninvasive Evaluation of Altered Cerebral Hemodynamics

BACKGROUND AND PURPOSE:SWI provides information about blood oxygenation levels in intracranial vessels. Prior reports have shown that SWI focusing on venous drainage can provide noninvasive information about the degree of brain perfusion in pediatric arterial ischemic stroke. We aimed to evaluate the influence of the SWI venous signal pattern in predicting stroke evolution and the development of malignant edema in a large cohort of children with arterial ischemic stroke.MATERIALS AND METHODS:A semiquantitative analysis of venous signal intensity on SWI and diffusion characteristics on DTI was performed in 16 vascular territories. The mismatch between areas with SWI-hypointense venous signal and restricted diffusion was correlated with stroke progression on follow-up. SWI-hyperintense signal was correlated with the development of malignant edema.RESULTS:We included 24 children with a confirmed diagnosis of pediatric arterial ischemic stroke. Follow-up images were available for 14/24 children. MCA stroke progression on follow-up was observed in 5/6 children, with 2/8 children without mismatch between areas of initial SWI hypointense venous signal and areas of restricted diffusion on DTI. This mismatch showed a statistically significant association (P = .03) for infarct progression. Postischemic malignant edema developed in 2/10 children with and 0/14 children without SWI-hyperintense venous signal on initial SWI (P = .07).CONCLUSIONS:SWI-DTI mismatch predicts stroke progression in pediatric arterial ischemic stroke. SWI-hyperintense signal is not useful for predicting the development of malignant edema. SWI should be routinely added to the neuroimaging diagnostic protocol of pediatric arterial ischemic stroke.

Acute arterial ischemic stroke (AIS) affects 2–5/100,000 children every year and is associated with high mortality and morbidity.¹ The mortality rate is estimated at 5%–13%, and moderate-to-severe neurologic deficits or epilepsy occur in >50% of children after AIS.^2,3 The Chest and American Heart Association guidelines support the use of anticoagulation in acute pediatric arterial ischemic stroke (PAIS) despite of the absence of large-scale clinical trials.^4,5 Antithrombotic therapy aims to prevent early propagation of the thrombus, inhibit the formation of new thrombus, and promote early recanalization to save hypoperfused tissue at risk of irreversible ischemic infarction. However, the diagnosis of PAIS should be made first, and tissue at risk for infarction should be detected. The diagnosis of PAIS is frequently delayed or missed.⁶ DWI/DTI is a highly sensitive MR imaging sequence in detecting early ischemic regions and is the diagnostic criterion standard for imaging acute PAIS.⁷ Neuroimaging techniques that allow early, reliable, noninvasive identification of potentially salvageable hypoperfused brain tissue—the so called ischemic penumbra—are imperative to guide treatment.SWI is a high-spatial-resolution, gradient-echo MR imaging sequence that accentuates the magnetic properties of various substances such as blood, blood products, nonheme iron, and calcification.⁸ In addition, SWI accentuates magnetic susceptibility differences between deoxygenated hemoglobin in the vessels and adjacent oxygenated tissues. A few previous reports have shown that SWI-hypointense signals in veins draining hypoperfused brain areas provide indirect evaluation of critically perfused tissue by focusing on venous drainage.^9–12 In addition, SWI-hyperintense signal was reported to detect regions of hyperperfusion and to be associated with an increased risk of developing postischemic malignant edema.¹³ SWI may consequently serve as a valuable alternative sequence to evaluate the hemodynamics of brain tissue in PAIS.The aims of this retrospective study were to evaluate the potential of acute SWI to identify potentially salvageable brain tissue and to predict the development of postischemic malignant edema in the largest cohort of PAIS reported so far, to our knowledge. We hypothesized that hypointense venous signal on acute SWI may identify brain tissue at risk of infarction progression by focusing on venous drainage and that the presence of SWI-hyperintense venous signal may predict the development of postischemic malignant edema.     

Physical inactivity in patients with rheumatoid arthritis: data from twenty-one countries in a cross-sectional, international study

OBJECTIVE: Regular physical activity is associated with decreased morbidity and mortality. Traditionally, patients with rheumatoid arthritis (RA) have been advised to limit physical exercise. We studied the prevalence of physical activity and associations with demographic and disease-related variables in patients with RA from 21 countries. METHODS: The Questionnaires in Standard Monitoring of Patients with Rheumatoid Arthritis (QUEST-RA) is a cross-sectional study that includes a self-report questionnaire and clinical assessment of nonselected consecutive outpatients with RA who are receiving usual clinical care. Frequency of physical exercise (>or=30 minutes with at least some shortness of breath, sweating) is queried with 4 response options: >or=3 times weekly, 1-2 times weekly, 1-2 times monthly, and no exercise. RESULTS: Between January 2005 and April 2007, a total of 5,235 patients from 58 sites in 21 countries were enrolled in QUEST-RA: 79% were women, >90% were white, mean age was 57 years, and mean disease duration was 11.6 years. Only 13.8% of all patients reported physical exercise>or=3 times weekly. The majority of the patients were physically inactive with no regular weekly exercise: >80% in 7 countries, 60-80% in 12 countries, and 45% and 29% in 2 countries, respectively. Physical inactivity was associated with female sex, older age, lower education, obesity, comorbidity, low functional capacity, and higher levels of disease activity, pain, and fatigue. CONCLUSION: In many countries, a low proportion of patients with RA exercise. These data may alert rheumatologists to motivate their patients to increase physical activity levels.     

Effect of Plaque Burden and Morphology on Myocardial Blood Flow and Fractional Flow Reserve

Background

Atherosclerotic plaque characteristics may affect downstream myocardial perfusion, as well as coronary lesion severity.