Short-term venous stasis influences routine coagulation testing.

Preanalytical variability is a common source of errors in coagulation testing, as clotting assays are particularly susceptible to poor standardization of the whole analytical process. To investigate the effect of a short-term venous stasis on routine coagulation testing, we measured activated partial thromboplastin time, prothrombin time, fibrinogen and D-dimer in plasma specimens collected either without venous stasis or following the application of a 60 mmHg constant, standardized external pressure by a sphygmomanometer, for 1 (1-min stasis) and 3 min (3-min stasis). When compared with blood specimens collected without stasis, the Pearson's correlation coefficients and the corresponding slopes of the Passing and Bablok regression line of samples collected following 1 and 3-min stasis were acceptable. However, statistically significant differences by paired Student's t-test could be observed for all parameters tests following 3-min stasis, and for all but the activated partial thromboplastin time after 1-min stasis. Significant difference between specimens collected after 1- and 3-min stasis was also achieved for prothrombin time (P < 0.01), fibrinogen (P < 0.01) and D-dimer (P < 0.05). The agreement between measurements was yet acceptable after 1-min stasis, but achieved clinical significance for prothrombin time, fibrinogen and D-dimer after 3-min stasis. Taken together, results of the present investigation confirm that the effects of venous stasis during venipuncture are clinically meaningful. As hematocrit values and activities of clotting factors VII, VIII and XII significantly increased, whereas that of activated factor VII remained unchanged, we hypothesize that a short-term venous stasis, as induced by up to 3-min tourniquet placing, might not be sufficient to produce additional procoagulant responses besides hemoconcentration.     

Venous hemodynamics in axillary venous stasis

By means of venous-occlusion plethysmography in 40 patients (24 men, 16 women) with stasis of the axillary vein the venous return was measured. This was 62.3 +/- 21.5 ml/100 ml/min. on the healthy arm. Long-term venous thromboses had worse return values (43.7%) than short occlusions (71.6% of the healthy side). Responsible for the favourable late results, which express themselves in increasing return values, is in general the development of an efficient collateral circulation and recanalisation, respectively, after thrombolysis or thrombectomy. The plethysmographic measurement of the back flow apart from the phlebography of the arm is recommended for the diagnosis and control of the course of the stasis of the axillary vein.     

Venous thromboembolism in patients with hematologic malignancy and thrombocytopenia

The optimal management of hematologic malignancy‐associated venous thromboembolism (VTE) in patients with moderate‐to‐severe thrombocytopenia is unclear. This is a retrospective study of 128 adult patients with hematologic malignancies who were diagnosed with VTE. The outcome of patients with significant thrombocytopenia (≤50,000/µL) was compared with those without. Forty‐seven patients (36.7%) had a platelet count ≤50,000/µL during a period of time of perceived need for new or continued anticoagulation. The median nadir platelet count in those with significant thrombocytopenia was 10,000/µL (range 2,000–45,000/µL) versus 165,000/µL (50,000–429,000/µL) in those without (P < 0.001). The median duration of significant thrombocytopenia in the first group was 10 days (1–35 days). Therapy during the period of significant thrombocytopenia included prophylactic‐dose low‐molecular‐weight heparin ( LMWH) (47%), therapeutic‐dose LMWH or heparin (30%), warfarin (2%), inferior vena cava filter (2%), and observation (17%). Patients without thrombocytopenia were managed with the standard of care therapy. At a median follow‐up of more than 2 years, the risk of clinically significant bleeding (11% vs 6%, P = 0.22) including major bleeding (6% vs 2%) and clot progression or recurrence (21% vs 22%, P = 1.00) were similar in patients with or without significant thrombocytopenia. In a multivariate analysis, the risk of recurrence/progression (hazard ratio, HR 0.59, 95% CI 0.21–1.66, P = 0.31) and hemorrhage rate (HR 0.29, 95% CI 0.05–1.56, P = 0.15) did not differ based on the presence of significant thrombocytopenia. Within the limits of this retrospective study, cautious use of prophylactic‐dose LMWH may be safe in thrombocytopenic patients with hematologic malignancy‐associated VTE. Am. J. Hematol. 91:E468–E472, 2016. © 2016 Wiley Periodicals, Inc.     

Venous stasis caused by extrinsic compression of the popliteal area

The authors present three clinical cases of venous compression of the popliteal area. They are two popliteal cysts and one tibial exostosis. A relatively frequent popliteal artery aneurysm and a few iatrogenic cases, complete the list of possible differential diagnoses. Ultrasonography seems to present definite advantages concerning its use and aiding phlebography, arteriography and arthrography in detecting a popliteal "mass" causing a proximal venous stasis.     

Lymphocyte subset counting by immunoperoxidase using an automated routine hematologic analyzer

Using monoclonal antibodies against CD2, CD4, CD8 and CD19 antigens and an automated biotin-avidin immunoperoxidase technique on whole blood samples, we evaluated the technical performance and clinical usefulness of lymphocyte subset counting by the routine hematology analyzer Technicon H*1. Statistical evaluation demonstrated excellent precision and very good correlation with the immunofluorimetric flow cytometer Ortho Spectrum III. Correlation between manual immunofluorescence at the microscope and the H*1 method was much poorer, owing to the high intrinsic imprecision of the manual method. Reference ranges obtained with the H*1 immunoperoxidase method in 44 healthy subjects closely matched those obtained with the Spectrum III. In 46 subjects with or at risk for HIV infection, we found with the H*1 method a significant decrease in CD4+ cells and in the CD4+/CD8+ cell ratio, which was progressively more marked in HIV- negative patients with lymphadenopathic syndrome, AIDS-related complex, and in patients with full-blown AIDS.     

Venous insufficiency and hemorheology. Influence of venous stasis on erythrocyte aggregation and disaggregation

The aim of this study was to assess the rheological properties of blood in patients with superficial venous insufficiency, in the very exact place of the hemodynamic disturbance i.e. in the veins of the lower limbs. MATERIAL AND METHODS: Several hemorheological parameters were studied in 20 patients (12 females and 8 males, 20 to 44 years old) with varicose veins of the lower limbs (insufficiency of the superficial venous system and no history of thrombosis). The results were compared to those obtained in 20 healthy controls matched for sex, age, weight and schedule for blood withdrawal. Two blood samples were obtained from the veins of the lower limbs of each subject: the first one at rest and the second after 10 minutes of "venous stasis" (standing position and 100 mm Hg tourniquet), in a temperature controlled room (22 degrees C). Every blood test was performed within one hour after blood withdrawal: --hematocrit (microcentrifugation) and fibrinogen (nephelometry); --plasma viscosity in a 37 degrees C temperature controlled capillary viscometer (Myrenne KSPV4); --erythrocyte filterability using the Hemorheometer (8% hematocrit and polycarbonate nuclepore membrane with a pore diameter of 5 microns); --erythrocyte aggregation and disaggregation (Myrenne AMM1 aggregometer and Erythroaggregometer SEFAM). RESULTS: 1. Hematocrit was not significantly different between both groups of subjects at rest. However, it increased significantly after venous stasis in patients with varicose veins (44.2% vs 41.8%, p. less than 0.05) and that was not found in controls. 2. At rest, the fibrinogen level was higher in patients than in controls (3.54 milligrams vs 2.41 milligrams, p less than 0.01). After statis, a significant increased was found only in the patients group (3.93 milligrams, p less than 0.05). 3. In a similar way, plasma viscosity at rest was significantly higher in patients (1.23 mPa.s) than in controls (1.11 mPa.s, p less than 0.01), and after stasis a further increase was found in the patients group (1.32 mPa.s, p less than 0.01). 4. Also the erythrocyte filterability index was altered at rest in patients (20.9) when compared to controls (15.1, p less than 0.01). A significant increase of this index was only found in the patients group (23, p less than 0.01). 5. Every aggregation parameters were significantly different at rest when comparing subjects groups, the most significant difference concerning the threshold of disaggregation (171.2 s-1 vs 106.8 S-1, p less than 0.001. Erythrocyte aggregation index was increased after stasis in patients but not in controls, with both 600 S-1 and 3 S-1 shear rates. 6. Positive correlations were found between low shear rate aggregation index on one hand and fibrinogen (r = 0.61), plasma viscosity (r = 0.51) and erythrocyte filterability index (r = 0.47) on the other hand...     

Assessing patient attitudes toward genetic testing for hereditary hematologic malignancy

Since 2003, more than 15 genes have been identified to predispose to hereditary hematologic malignancy (HHM). Although the yield of germline analysis for leukemia appears like that of solid tumors, genetic referrals in adults with leukemia remain underperformed. We assessed leukemia patients' attitudes toward genetic testing and leukemia-related distress through a survey of 1093 patients diagnosed with acute or chronic leukemia, myelodysplastic syndrome, or aplastic anemia. Principal component analysis (PCA) was used to analyze patient attitudes. Distress was measured through the Impact of Event Scale-Revised (IES-R). Exactly 19.8% of eligible respondents completed the survey. The majority reported interest in (77%) or choosing to have (78%) genetic testing for HHM. Slightly over half identified worry about cost of genetic testing (58%) or health insurance coverage (61%) as possible barriers. PCA identified relevant themes of interest in genetic testing, impact on leukemia treatment, discrimination and confidentiality, psychosocial and familial impacts, and cost of testing. The majority reported low distress. Leukemia patients report high interest in genetic testing, few barriers, and relatively low distress.     

Ventricular tachycardia during routine treadmill testing. Risk and prognosis

Exercise-induced ventricular tachycardia during exercise testing is considered to increase risk during testing. Moreover, exercise-induced ventricular tachycardia has been considered to confer a poor prognosis although this has not been specifically studied. On a retrospective review of 3351 patients who had undergone routine clinical exercise testing between September 1984 and June 1989, we identified 55 patients with exercise-induced ventricular tachycardia. The mean follow-up was 26 months (range, 2 to 58 months). Fifty patients had nonsustained ventricular tachycardia during exercise testing and one of these patients died due to congestive heart failure during the follow-up period. Five patients had sustained ventricular tachycardia during exercise testing and one died suddenly 7 months after the test. Ventricular tachycardia was reproduced in only two of the 29 patients who underwent repeated exercise testing. Ventricular tachycardia during routine clinical exercise testing occurred rarely (prevalence of 1.5%) and was not associated with complications during testing. The total mortality in the exercise-induced ventricular tachycardia group (3.6%) was not significantly different from the mortality in the entire population (5.1%). Nonsustained ventricular tachycardia occurring during clinical exercise testing is not an independent marker of a poor prognosis.     

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随着现代电子技术和生物工程学的飞速发展,肺功能仪不断推陈出新。选用肺功能仪,主要从3个方面进行考虑:一是仪器的适用性,是指适合医院自身情况、能真正用于开展业务的仪器。二是仪器的性价比,是指性能优越、计量准确,且价格合理的仪器。三是售后服务与技术支持,是指故障率低且维修服务及时的仪器。肺功能仪的日常维护是仪器可靠性的保障,其中流速/容量校准、检测气体浓度校准等日常仪器校准是重要内容,当仪器已使用多年或疑有测量误差过大时,建议采用标准呼吸模拟器进行质量检测。     

Use of NT-proBNP in routine testing and comparison to BNP

OBJECTIVES: B-type natriuretic peptide (BNP) is a strong diagnostic predictor of left-ventricular (LV)-dysfunction. Recently, the aminoterminal portion of pro-BNP (NT-proBNP) has been introduced, which could be even more sensitive because of its longer half-life. The aim of this study was to evaluate the new marker NT-proBNP within a large, heterogeneous population of patients with suspected cardiovascular disease at risk of cardiovascular dysfunction and to compare it with the established diagnostic parameter BNP. SUBJECTS AND METHODS: NT-proBNP and BNP were measured in 339 hospitalised patients undergoing diagnostic angiography (median age 66 years, 244 male vs. 95 female). RESULTS: Median values of NT-proBNP increased with worsening LV-dysfunction and higher NYHA class. The area under the receiver operator characteristics curve (AUC) of NT-proBNP for detecting severe systolic dysfunction or for detecting any systolic LV-dysfunction was 0.83 and 0.77, respectively. The latter improved (AUC=0.81) when patients with clinically relevant heart disease like valvular dysfunction were included, independent of the haemodynamic values. Compared to BNP, NT-proBNP tended to be more accurate in identifying lesser degrees of LV-dysfunction. CONCLUSIONS: Even after optimisation of target criteria, there was still a substantial overlap of NT-proBNP values between patients with and without relevant heart disease. Therefore, NT-proBNP is not suitable as a screening test for LV-dysfunction in the community. Nevertheless, because of its good negative predictive value, NT-proBNP could be an easy and effective tool to rule out severe systolic LV-dysfunction in high risk patients. No clinically significant advantage of BNP testing could be found.     

Transillumination: a new tool to eliminate the impact of venous stasis during the procedure for the collection of diagnostic blood specimens for routine haematological testing

Introduction: The collection of diagnostic blood specimens for routine haematological testing (RHT) is traditionally performed with tourniquet. However, the transillumination devices based on cold near‐infrared LEDs have been formerly proposed as a valuable tool for identifying reliable venous accesses, especially in patients with difficult or small veins, such as children. This study was aimed to evaluate whether a transillumination device can advantageously replace the use of the tourniquet during the procedure for collection of blood specimens for RHT and thereby eliminating the discomfort and risk of spurious results caused by excessive or prolonged venous stasis. Methods: Two hundred and fifty volunteers were divided into five groups (G1, G2, G3, G4 and G5) to compare the results of RHT between blood sample collected with transilluminator device (left arm) and with tourniquet application (right arm) for 30 s(G1), 60 s(G2), 90 s(G3), 120 s(G4) and 180 s(G5). Results: No significant increases were observed in any of the haematological parameters tested in G1 when compared with blood collected by the transilluminator device. From G2 to G5, significant increases were observed for the platelet count, red blood cell count, haemoglobin, haematocrit, white blood cell count, neutrophils, monocytes and eosinophils. From G3–G5, further increases were observed for lymphocytes. Clinically significant variations were, however, observed for basophils in G2; red blood cell count, haemoglobin, haematocrit and basophils in G3 and eosinophils in G3 only. Conclusion: As such, considering that inappropriate use of the tourniquet is commonplace, we conclude that transillumination devices can represent a suitable tool to eliminate the venous stasis and to improve the quality of phlebotomy procedures.