Biomedical subjects
Giuseppe Lippi
Publications and source records attributed to Giuseppe Lippi.
Plasma D-dimer variation following elective orthopedic surgery.
Explore the source record for details and available documents.
Influence of warfarin therapy on activated factor VII clotting activity.
Oral anticoagulant therapy has been widely employed to prevent and treat a variety of thrombotic disorders, although a new generation of antithrombotic drugs, which offer inhibition of clot-bound as well as fluid-phase thrombin, has been developed and tested in several clinical trials. Although most anticoagulant responses to hydroxycoumarin compounds are well established, there are controversial evidences on their influence on activated factor VII (FVIIa). After analyzing the prothrombin time (PT) (International Normalized Ratio reference range, 0.92-1.08), factor VII clotting activity (FVII:C) (reference range, 75-130 U/dl) and activated factor VII clotting activity (FVIIa:C) (reference range, 30-110 U/l) in 46 consecutive patients on stable warfarin therapy for atrial fibrillation, a consistent trend towards decreased values of both FVII:C and FVIIa:C was observed as PT values increased. At moderate-intensity anticoagulation, with international normalized ratios between 2 and 3, the mean activities of FVII:C and FVIIa:C dropped to 28 U/dl (range, 9-61 U/dl) and 5.8 U/l (range, 1-18 U/l), respectively. Results of our investigations indicate that warfarin therapy decreases FVIIa:C, highlighting the potential benefits of oral anticoagulants in thrombotic disorders and other clinical conditions characterized by increased levels of FVIIa. Owing to the good correlation with FVIIa:C, we also hypothesize that the PT and/or FVII:C might be employed for monitoring recombinant FVIIa therapy.
Efficacy of desmopressin in preventing hemorrhagic complications in a patient with Marfan syndrome undergoing cardiac surgery.
In this case report, we describe the successful use of desmopressin as prophylaxis against hemorrhage in a patient with a bleeding tendency associated with Marfan syndrome and a platelet function defect undergoing cardiovascular surgery.
Quality and reliability of routine coagulation testing: can we trust that sample?
Poor standardization of preanalytic variables exerts a strong influence on the reliability of coagulation testing, consuming valuable health care resources and compromising patient outcome. Most uncertainties emerge from patient misidentification and the procedures for specimen collection and handling. Location of unsuitable venous access or problematic phlebotomies may produce spurious activation of the hemostatic system and hemolytic specimens. Prolonged venous stasis is associated with hemoconcentration and spurious variations of most coagulation assays. Additional pitfalls can be introduced by inappropriate phlebotomy tools and small-gauge needles. Inappropriate filling and mixing of the tube, unsuitable procedures for centrifugation and storage of the specimens are additional aspects that need accurate standardization. Besides traditional preanalytic variables affecting routine coagulation testing, thrombin-generation assays require specific criteria to be accurately fulfilled. These aspects include the type of specimen (platelet-poor plasma, platelet-rich plasma or whole blood), blood collection tubes, storage conditions and the presence of residual platelets. Compliance with new international quality assessment programs, which will also involve coagulation laboratories, encompasses the adoption of suitable strategies for reducing undue variability throughout the whole testing process. Such strategies would not entail extraordinary costs and are affordable with a structured outlay of existing resources, educational policies and compliance with reliable guidelines.
Influence of the needle bore size on platelet count and routine coagulation testing.
The phlebotomy technique, particularly the use of small-bore needles, may influence the reliability of coagulation testing and platelet count. Routine coagulation tests were assayed in blood specimens collected from 22 consecutive patients in three separate, sequential phlebotomies, using butterfly devices with different needle sizes. Test results of samples collected with 23 and 25 G needles were compared with those obtained with the currently recommended 21 G needle. Although both the prothrombin time and activated partial thromboplastin time displayed a trend towards lower values employing the smaller 23 and 25 G needles, results did not differ significantly from the reference 21 G needle specimen, with the exceptions of D-dimer (25 G versus 21 G needle, 186 +/- 70 versus 178 +/- 66/ml, P < 0.01) and platelet count (23 G versus 21 G needle, 246 +/- 55 versus 254 +/- 56 x 10(-3)/l, P < 0.01; 25 G versus 21 G needle, 240 +/- 55 versus 254 +/- 56 x 10(-3)/l, P < 0.01). None of the mean biases recorded for the parameters was clinically meaningful, nor did they exceed the current desirable analytical quality specifications for desirable bias. Results of the present investigation suggest that, when a proper technique is used and within certain limitations, butterfly devices with small-bore needles may be a reliable alternative to draw venous blood for platelet count and coagulation testing.
Thyroid status in patients with systemic sclerosis.
Explore the source record for details and available documents.
The use of recombinant activated factor VII in congenital and acquired von Willebrand disease.
Recombinant activated factor VII (NovoSeven), a novel hemostatic agent originally developed for the treatment of bleeding episodes in hemophilia A or B patients with inhibitors, has been recently employed with benefit for the management of hemorrhages in other nonhemophilic congenital and acquired hemostatic abnormalities. This review focuses on the use of this drug in acquired and congenital von Willebrand disease. The analysis of the literature data shows that recombinant activated factor VII is an effective agent for the treatment of refractory bleeding in von Willebrand disease patients and for the treatment or prevention of bleeding in those patients with alloantibodies or autoantibodies against von Willebrand factor. Further studies are needed, however, to assess its safety and to optimize the dosages and regimens of therapy in such patients.
Evaluation of four portable self-monitoring blood glucose meters.
Self-monitoring of blood glucose (SMBG) is a cornerstone of diabetes care. However, the effectiveness of any glucose-monitoring programme depends on the ability to integrate SMBG into a program of self-care and therapeutic decision-making. Because the accuracy of SMBG is instrument dependent, we analysed 45 heparinized whole blood specimens using four marketed portable glucose meters to evaluate whether their precision and accuracy would be efficient and safe for clinical use. All measurements were standardized and performed by a single expert health-care professional at the same clinical chemistry laboratory. Results were compared with those obtained on the same plasma samples by the hexokinase method on a secondary reference analyser and further analysed according to the error tolerance criteria and the current American Diabetes Association (ADA), Clinical Laboratory Improvement Amendments (CLIA), and National Committee for Clinical Laboratory Standards (NCCLS) guidelines. The within-run imprecision ranged from 2.2% to 3.2%. Passing and Bablok regression analysis yielded slope values from 0.93 to 1.07 and correlation coefficients between 0.994 and 0.998. When compared with the secondary reference analyser, mean variations were between -4.9% and 14.1%, fulfilling in three out of four cases the 5.5% current desirable analytical quality specifications for total error. Nevertheless, when considering the two standard deviations level of this bias, several results exceeded this limit. Although three out of four devices tested achieved or came closer to the NCCLS C30-A2, CLIA and error tolerance targets, none of them met the current analytical ADA thresholds. Despite the acceptable analytical performances, we demonstrated that standardization and harmonization of results in SMBG have not been fully achieved.
Influence of centrifuge temperature on routine coagulation testing.
Explore the source record for details and available documents.
Preanalytic error tracking in a laboratory medicine department: results of a 1-year experience.
Explore the source record for details and available documents.
Reliability of the thrombin-generation assay in frozen-thawed platelet-rich plasma.
Explore the source record for details and available documents.
Ischemia-modified albumin and NT-prohormone-brain natriuretic peptide in peripheral arterial disease.
Cardiovascular disease is the leading cause of mortality and morbidity in Western countries. Despite its remarkable medical and social consequences, the prevalence of peripheral arterial disease (PAD) is often underestimated among atherosclerotic disorders. So far, little is known about the behavior of traditional and emerging markers of ischemic heart disease that should allow the reliable identification of PAD patients at increased risk of developing myocardial ischemia and heart failure or dysfunction. To investigate this topic, we measured cardiac troponin T (cTnT), ischemia-modified albumin (IMA) and NT-prohormone-brain natriuretic peptide (NT-proBNP) in 35 consecutive patients with clinically ascertained PAD (stage 2-4, according to Lériche-Fontaine) asymptomatic for chest pain and current heart failure, and 20 controls displaying moderate to high cardiovascular risk factors (hypertension, diabetes, hyperlipidemia), but with no clinical evidence of PAD. Although the concentrations of cTnT and IMA were not statistically increased in PAD patients, NT-pro-BNP values were substantially higher in PAD patients than in controls (62.6 vs. 7.4 pmol/L, p<0.0001). The percentage of subjects displaying values exceeding the specific NT-proBNP diagnostic threshold (>14.8 pmol/L) was also significantly different between PAD patients and controls (74% vs. 10%, p<0.001). After excluding PAD patients exceeding the 0.01 ng/mL cTnT cutoff value indicative of current ischemic cardiac involvement, the median concentration of NT-proBNP remained statistically increased (28.0 vs. 5.8 pmol/L, p<0.0001). Taken together, these results indicate that NT-proBNP, but not IMA, is substantially increased in PAD patients. This finding suggests that such patients, even though asymptomatic, might develop myocardial dysfunction, and thus warrant further investigation.
Influence of hemolysis on routine clinical chemistry testing.
BACKGROUND: Preanalytical factors are the main source of variation in clinical chemistry testing and among the major determinants of preanalytical variability, sample hemolysis can exert a strong influence on result reliability. Hemolytic samples are a rather common and unfavorable occurrence in laboratory practice, as they are often considered unsuitable for routine testing due to biological and analytical interference. However, definitive indications on the analytical and clinical management of hemolyzed specimens are currently lacking. Therefore, the present investigation evaluated the influence of in vitro blood cell lysis on routine clinical chemistry testing. METHODS: Nine aliquots, prepared by serial dilutions of homologous hemolyzed samples collected from 12 different subjects and containing a final concentration of serum hemoglobin ranging from 0 to 20.6 g/L, were tested for the most common clinical chemistry analytes. Lysis was achieved by subjecting whole blood to an overnight freeze-thaw cycle. RESULTS: Hemolysis interference appeared to be approximately linearly dependent on the final concentration of blood-cell lysate in the specimen. This generated a consistent trend towards overestimation of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, creatine kinase (CK), iron, lactate dehydrogenase (LDH), lipase, magnesium, phosphorus, potassium and urea, whereas mean values of albumin, alkaline phosphatase (ALP), chloride, gamma-glutamyltransferase (GGT), glucose and sodium were substantially decreased. Clinically meaningful variations of AST, chloride, LDH, potassium and sodium were observed in specimens displaying mild or almost undetectable hemolysis by visual inspection (serum hemoglobin < 0.6 g/L). The rather heterogeneous and unpredictable response to hemolysis observed for several parameters prevented the adoption of reliable statistic corrective measures for results on the basis of the degree of hemolysis. CONCLUSION: If hemolysis and blood cell lysis result from an in vitro cause, we suggest that the most convenient corrective solution might be quantification of free hemoglobin, alerting the clinicians and sample recollection.
Comparison of the lipid profile and lipoprotein(a) between sedentary and highly trained subjects.
BACKGROUND: There is consolidated evidence that physical activity exerts beneficial effects on several chronic conditions and longevity, on the basis of its proposed biological effects, especially on lipid profiles. However, debate continues regarding the intensity of activity required for good health, as vigorous physical activity might overwhelm advantageous changes. In addition, little is known so far on the effect of a vigorous and regular aerobic training regimen on emerging markers of cardiovascular risk, such as lipoprotein(a), total/high-density lipoprotein cholesterol ratio and the atherogenic index of plasma. METHODS: To further investigate this topic, an extensive lipid profile, in accordance with the most recent guidelines issued by the American Heart Association (AHA)/American College of Cardiology (ACC) and the National Cholesterol Education Program (NCEP), was evaluated in 60 healthy male sedentary controls and in a wide population of professional endurance athletes, including 40 male professional cross-country skiers and 102 male professional road cyclists. RESULTS: Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), triglycerides, TC low-density lipoprotein cholesterol (LDL-C) ratio and the atherogenic index of plasma were significantly lower in both categories of professional athletes, whereas the mean HDL-C concentration was significantly higher. The concentration of lipoprotein(a) did not differ significantly between the groups. When compared to current NCEP or AHA/ACC goals, the percentage of patients with undesirable values was statistically different for all parameters tested, apart from lipoprotein(a). According to multiple stepwise logistic regression analysis, lower TC/HDL-C ratio in professional skiers and lower TC/HDL-C ratio and TC in professional cyclists were significantly associated with increased aerobic physical activity. CONCLUSIONS: Results of this case-control study confirm that elevated aerobic energy expenditure might be associated with a highly favorable stabilization of most traditional and emerging cardiovascular risk predictors. Therefore, a substantial increase in aerobic physical activity within the population might be recommended to reverse adverse lipid abnormalities, especially in subjects with a higher cardiovascular risk.
Preanalytical variability: the dark side of the moon in laboratory testing.
Remarkable advances in instrument technology, automation and computer science have greatly simplified many aspects of previously tedious tasks in laboratory diagnostics, creating a greater volume of routine work, and significantly improving the quality of results of laboratory testing. Following the development and successful implementation of high-quality analytical standards, analytical errors are no longer the main factor influencing the reliability and clinical utilization of laboratory diagnostics. Therefore, additional sources of variation in the entire laboratory testing process should become the focus for further and necessary quality improvements. Errors occurring within the extra-analytical phases are still the prevailing source of concern. Accordingly, lack of standardized procedures for sample collection, including patient preparation, specimen acquisition, handling and storage, account for up to 93% of the errors currently encountered within the entire diagnostic process. The profound awareness that complete elimination of laboratory testing errors is unrealistic, especially those relating to extra-analytical phases that are harder to control, highlights the importance of good laboratory practice and compliance with the new accreditation standards, which encompass the adoption of suitable strategies for error prevention, tracking and reduction, including process redesign, the use of extra-analytical specifications and improved communication among caregivers.
Laboratory medicine in the 2000s: programmed death or rebirth?
Changes have occurred in the organization, complexity and role of medical laboratories in healthcare, requiring a great increase in global productivity and diagnostic efficiency by enrolled professionals to withstand new challenges. Such a radical evolution, which should be very attractive for new generations of professionals, is counterbalanced by an increasing shortage of laboratory vocations worldwide, particularly in community hospital and large reference laboratories, which may lead to a serious crisis in the field of laboratory medicine in the very near future. Some reasons can be highlighted, including the decreased interaction between clinicians and laboratory professionals, centralized testing, and the development of innovative, minimally invasive techniques that can easily be handled without direct control or supervision by laboratory staff. The prospect of a professional decline in laboratory medicine can be offset by increased awareness of the radical changes occurring within clinical laboratories and re-professionalization of laboratory scientists. This will require new resources to attract young professionals, and should include reaffirmation of the role of laboratory consultants and active participation in the development, implementation and monitoring of innovative diagnostic systems. The "patient" appears to be in a serious condition; it is in our hands to let him be reborn.
Influence of the needle bore size used for collecting venous blood samples on routine clinical chemistry testing.
BACKGROUND: Despite remarkable advances in technology and laboratory automation, results of laboratory testing still suffer from a high degree of preanalytical variability. Although there is no definitive evidence, the use of small-gauge needles for venipuncture is usually discouraged to reduce the chance of producing unsuitable specimens. METHODS: The purpose of this investigation was to assess the influence of the needle size used to collect venous blood on the measurement of 14 common analytes, including free hemoglobin, the most representative enzymes, protein-bound substances and electrolytes. Results for venous blood samples collected from 20 fasting voluntary physicians using either a 23- (0.60 mmx19 mm) or 25-gauge-needle (0.50 mmx19 mm) butterfly devices with polyvinyl chloride tubing (1.40 mmx300 mm) were compared with reference specimens collected using a 21-gauge-needle (0.80 mmx19 mm) butterfly device with polyvinyl chloride tubing (1.40 mmx300 mm). RESULTS: All means for paired samples collected using the smaller needles did not differ significantly from the reference specimen by paired Student's t-test analysis. Passing-Bablok regression analysis and Pearson's or Spearman (creatine kinase, aspartate aminotransferase, alanine aminotransferase and chloride) correlation were acceptable for most of the analyses, although a lower correlation coefficient was observed for electrolytes. In addition, when expressed as a percentage of the mean for paired samples, the s(y,x) value exceeded the desirable bias for free hemoglobin, glucose, lactate dehydrogenase, aspartate aminotransferase, sodium, chloride, calcium and magnesium (in samples collected using both 23 G and 25 G needles) and potassium (in samples collected using a 25 G needle). Although Bland-Altman plot analysis and +/-1.96 SD agreement intervals for the set of differences between values was acceptable overall, the bias was rather broad for free hemoglobin and several critical electrolytes (calcium, chloride, potassium, sodium), exceeding the respective limits for desirable bias. CONCLUSIONS: The results of our investigation indicate that 23 G needles, if handled correctly, will not introduce any statistically or clinically significant error to the measurement results compared to a 21 G needle. For the 25 G needle, we observed increased variability for potassium compared to a 23 G needle. Small-bore needles of 25 G or less cannot be universally recommended when collecting venous blood for clinical chemistry testing and should be reserved for selected circumstances, such as in patients with problematical venous accesses and newborns. In such cases, however, the bias introduced by the use of smaller needles should always be taken into consideration when interpreting test results.