[Relationship between prothrombin time international normalized ratio and thrombo test (%)].

OBJECTIVES: The optimal therapeutic range for laboratory evaluation of oral anticoagulant therapy is now defined by the prothrombin time international normalized ratio (PT-INR). However, the thrombo test (TT), an alternative method to measure intensity of anticoagulation, is also currently used throughout Japan. The relationship between PT-INR and TT (%) has yet to be clarified. This study investigated the relationship between PT-INR and TT (%). METHODS: The PT-INR and TT (%) were simultaneously measured of 505 consecutive samples from patients treated with warfarin in our hospital. Fourteen functions were used for regression analyses: a fractional function (Y = a/X + b), a square root function (Y = aX0.5 + b), a natural logarithmic function (Y = a.lnX + b), a power series function (Y = aXb), a quotient function (Y = abX), and polynomial functions [Y = anXn + an - 1Xn - 1 +......+ a1X1 + b, (1 < or = n < or = 9)]. The results were confirmed by the same methods in 383 samples and 296 samples from another two laboratories. RESULTS: The power series function showed the most significant (p < 0.0001) and highest adjusted R2 (0.858) correlation, with a regression formula of TT (%) = e4.48 (PT-INR)-2.09 in our laboratory. Using the same analyses, the power series function also showed the most significant and highest adjusted R2 in samples from the other two laboratories. CONCLUSIONS: This study showed that a power series function is the most appropriate for expressing the relationship between PT-INR and TT (%) among the 14 functions. The function between PT-INR and TT (%) is mainly derived from the relationship between TT (%) and TT (sec). Both internal validity and external validity confirmed the relationship between PT-INR and TT (%).

Can cytokines be removed by hemofiltration or hemoadsorption?

To study the removability of pro-inflammatory cytokines by hemofiltration (HF), we performed experimental HF with various high-flux membranes (HFM) using a closed circuit system filled with monocyte-free human plasma, which contained TNFalpha, IL-1beta, and IL-6. Plasma and filtrate samples were taken before and 1, 2, 3, and 4 hours after the initiation of HF, and each cytokine was determined by enzyme-linked immunosorbent assay. IL-1beta was well removed through filtration during experimental HF using HFM (PAN>CTA>PMMA>PS). TNFalpha and IL-6 were only minimally filtered out by HF using HFM. TNFalpha was removed to some extent by using PS, and IL-6 was partially removed by using PMMA during experimental HF through other mechanisms, such as adsorption, than the filtration. IL-1beta and IL-6 were effectively removed by HA using charcoal adsorbent column, especially during the first 2 hours, while TNFalpha was only partly removed.

Clinical application of vascular closure staple clips for blood access surgery.

We investigated the usefulness of nonpenetrating titanium vascular closure staple (VCS) clips developed for anastomosis of peripheral blood vessels. VCS clip applier systems (Autosuture; United States Surgical Corporation, Norwalk, CT) were used for 10 patients on hemodialysis who needed peripheral vascular anastomoses for blood access. Two arteriovenous (AV) fistulas, one closure of a fistula with reconstruction of the radial artery, six vascular graft implantations, and one vascular graft closure were performed. Medium clips were used for AV fistulas and large clips for vascular graft implantation. It took 12 min, on average, for vascular access graft anastomoses and 8.5 min, on average, for the AV fistulas. In two patients, bleeding from the anastomosed site occurred after declamping and additional sutures were required; however, neither hematoma nor wound infection occurred at 9 to 12 months after surgery. In one patient, stenosis of the graft-venous junction was found and was successfully treated by percutaneous transluminal angioplasty. The VCS clip applier is easy to manipulate, is as safe as hand-suture methods, and has time saving potential. We conclude that these VCS clips are useful for vascular anastomoses of blood access.