Efficacy and safety of heparinase I versus protamine in patients undergoing coronary artery bypass grafting with and without cardiopulmonary bypass

BACKGROUND

Hemodynamic protamine reactions with heparin reversal during cardiac surgery are common and associated with adverse outcomes. As an alternative to protamine, the authors examined heparinase I reversal of heparin after aortocoronary bypass graft surgery.

METHODS

In a randomized, double-blind, double-dummy trial, 167 on- and off-pump aortocoronary bypass graft surgery patients received either heparinase I (maximum 35 microg/kg) or protamine (maximum 650 mg) for heparin reversal, monitored by activated clotting time values and clinical assessment. Hemodynamic parameters were recorded electronically; safety evaluation was to 30 days postoperatively. Noninferiority was predefined as 400 ml or less median 12-h chest tube drainage from intensive care unit arrival for heparinase I patients, after risk adjustment. Hemodynamic instability was defined as systemic hypotension (> or = 30 mmHg decrease) and/or pulmonary hypertension (> or = 40 mmHg with an increase > or = 10 mmHg) within 30 min of heparin reversal initiation.

RESULTS

Patient enrollment was terminated on advisement of the Data Safety Monitoring Board. Although heparinase I was noninferior for 12-h chest tube drainage, protamine had a superior safety profile. Overall, heparinase I subjects had longer hospital stays (P = 0.04), were more likely to experience a serious adverse event (P = 0.01), and were less likely to avoid transfusion (P = 0.006). A composite morbidity score was not different (P = 0.24), and similar rates of hemodynamic instability were observed between groups. Findings were consistent in analyses stratified by on- and off-pump surgery.

CONCLUSIONS

Heparinase I reverses heparin anticoagulation after aortocoronary bypass graft surgery but is not equivalent to protamine because of its inferior safety profile.

Nontoxic membrane translocation peptide from protamine, low molecular weight protamine (LMWP), for enhanced intracellular protein delivery: in vitro and in vivo study

Naturally derived, nontoxic peptides from protamine by the authors, termed low molecular weight protamines (LMWPs), possess high arginine content and carry significant sequence similarity to that of TAT, by far the most potent protein transduction domain peptide. Therefore, it was hypothesized that these LMWPs would also inherit the similar translocation activity across the cell membrane, which enables any impermeable species to be transduced into the cells. LMWPs were prepared by enzymatic digestion of protamine, examined their capability of transducing an impermeable protein toxin into the tumor cells by chemical conjugation, and determined cytotoxicity of transduced protein toxin (e.g., gelonin) against cancer cell lines and a tumor-bearing mouse. In vitro results showed that LMWPs could indeed translocate themselves into several mammalian cell lines as efficiently as TAT, thereby transducing impermeable gelonin into the cells by chemical conjugation. In vivo studies further confirmed that LMWP could carry an impermeable gelonin across the tumor mass and subsequently inhibit the tumor growth. In conclusion, the presence of equivalent cell translocation potency, absence of toxicity of peptide itself, and the suitability for low-cost production by simple enzymatic digestion could expand the range of clinical applications of LMWPs, including medical imaging and gene/protein therapies.

Antiphospholipid syndrome in cardiac surgery—an underestimated coagulation disorder?☆

OBJECTIVE

Antiphospholipid syndrome (APS) is a rare coagulation disorder associated with recurrent arterial and venous thrombotic events. We analysed our experience with five APS patients who underwent cardiac surgery. In three of them the diagnosis of APS had been established before surgery, two patients were diagnosed after surgery.

METHODS

From March 1999 to March 2004 five patients with APS underwent cardiac surgery using cardiopulmonary bypass (CPB). We retrospectively reviewed their clinical data, operative and postoperative courses, and the long-term results.

RESULTS

Procedures performed were heart and lung transplantation (patient 1), endoventriculoplasty and CABG (patient 2), biventricular resection of endoventricular fibrosis and thrombus (patient 3), mitral valve repair repair and coronary artery bypass grafting (CABG, patient 4), and mitral valve replacement with closure of a patent foramen ovale (patient 5). There were three perioperative deaths (patients 1, 2 and 3), two of three patients in whom the diagnosis was known before surgery, survived (patients 4 and 5). In these patients, only half the dose of protamin (patient 4) and no protamin at all (patient 5) was applied to reduce the probability of postoperative thromboembolic complications. At 1 year follow up, only patient 4 had survived, patient 5 had died of the complications of intestinal thromboembolism.

CONCLUSIONS

Patients with APS undergoing cardiac surgery belong to a high risk subgroup. Thus, though rare, APS can be a critical issue in cardiac surgery. Some of the cardiac patients with unexplained perioperative thromboembolic complications, such as graft occlusion, may turn out to have an undiagnosed APS.

Life-Threatening Hemorrhage After Dalteparin Therapy in a Patient with Impaired Renal Function

Dalteparin and other low-molecular-weight heparins are frequently used for the treatment of deep vein thrombosis and for other indications. Unlike unfractionated heparin (UFH), dalteparin is mainly cleared through the kidney; therefore, it can accumulate in patients with impaired renal function, increasing the risk of hemorrhage. An 84-year-old woman with chronic renal failure was hospitalized because of stenosis of a femorofibular bypass in her right leg. Peripheral transluminal angioplasty was performed successfully. Later the same day, Doppler sonography revealed deep vein thrombosis of the left lower leg. Treatment with dalteparin was started. The patient was discharged home 3 days later, with dalteparin to be continued at home. One day later, the patient was rehospitalized because of a pronounced hematoma on her flank. Her hemoglobin level had dropped to 5.5 g/dl. Treatment with dalteparin was stopped, and protamine 2500 U and two transfusions of packed red blood cells were administered. Treatment with UFH and oral anticoagulants were started because of a persistent risk for venous thrombosis. Thereafter, the patient's hemoglobin level remained stable, and no further bleeding episodes occurred. As long as systematic studies of the efficacy and safety of dalteparin in patients with severe renal impairment are lacking, dalteparin should be avoided or used only with close monitoring of antifactor Xa activity in these patients. As an alternative, UFH can be used because monitoring of UFH is well established and easier than it is with dalteparin. Renal impairment does not notably influence the short elimination half-life of UFH, which unlike that of dalteparin or other low-molecular-weight heparins allows for rapid dosage adjustments to prevent hemorrhage.

Filter Run Time in CVVH: Pre- versus Post-Dilution and Nadroparin versus Regional Heparin-Protamine Anticoagulation

BACKGROUND/AIMS

To study the effect of different modes of continuous veno-venous haemofiltration (CVVH) on filter run time (FRT).

METHODS

We studied, in two consecutive prospective, randomised and crossover studies, 16 and 15 patients with acute renal failure during critical illness. Study A compared pre- versus post-dilution, and study B compared regional anticoagulation with heparin (pre-filter) and protamine (post-filter) (HP) versus nadroparin (NP) pre-filter. All CVVH sessions were standardised. Analyses were by Wilcoxon rank sum tests.

RESULTS

Study A: During pre-dilution the median FRT was 45.7 vs. 16.1 h in post-dilution CVVH (p = 0.005). The median creatinine clearance during pre-dilution was 33 vs. 45 ml/min in post-dilution (p = 0.001). Study B: During NP, median FRT was 39.5 vs. 12.3 h during HP CVVH (p = 0.045).

CONCLUSIONS

Pre-dilution CVVH results in the greatest FRT but a lower plasma creatinine clearance compared to post-dilution. Regional anticoagulation with heparin-protamine resulted in a significantly shorter FRT compared to systemic NP anticoagulation.

[Pulmonary hemorrhage after abciximab. Risk factors and the role of protamine]

Large clinical trials have demonstrated the clinical effectiveness of therapy with inhibitors of the platelet surface-membrane glycoprotein IIb-IIIa receptor in a broad range of patients with ischemic heart disease. Abciximab, a platelet glycoprotein IIb-IIIa receptor blocker, is associated with improved long-term prognosis in patients who require angioplasty and stent placement. Severe bleeding from abciximab use is an uncommon event. We describe a patient with severe pulmonary hemorrhage after treatment with abciximab, and discuss predisposing factors and protamine infusion in this potentially fatal complication.

Comparison of epsilon aminocaproic acid and tranexamic acid in pediatric cardiac surgery

OBJECTIVE

This study compared the efficacy of aminocaproic acid and tranexamic acid in reducing postoperative blood loss, as well as blood and blood product requirements in children with cyanotic congenital heart disease.

DESIGN

A prospective randomized study.

SETTING

Cardiac center of a tertiary care, referral hospital.

PARTICIPANTS

One hundred fifty children in the age group of 2 months to 14.5 years with cyanotic congenital heart disease undergoing corrective surgery on cardiopulmonary bypass (CPB).

INTERVENTIONS

Patients were randomized into 3 groups. Group A was given aminocaproic acid in a dose of 100 mg/kg after anesthetic induction, 100 mg/kg on CPB and 100 mg/kg after protamine. Group T was given tranexamic acid, 10 mg/kg, after anesthetic induction, 10 mg/kg on CPB, and 10 mg/kg after protamine. Group C was the control group.

MAIN RESULT

Control group had the longest sternal closure time, maximum blood loss at 24 hours, and maximum requirements of blood and blood products. Among the 2 groups given antifibrinolytics, there was no significant difference in postoperative blood loss, blood and product requirement, and reexploration rates.

CONCLUSION

Aminocaproic acid and tranexamic acid are equally effective in reducing postoperative blood loss, as well as blood and blood product requirements in children with cyanotic heart disease undergoing corrective surgery as compared with the control group.

Blood Conservation Strategies in Cardiovascular Surgery

Blood conservation is a measurable intervention in which clinical and financial outcomes may be tracked. This article describes a systems approach to blood conservation for a cardiac surgery population. Four key areas are discussed: needs assessment, committee construction, blood conservation strategies, and outcome measurement. Specific evidenced-based blood conservation strategies include, but are not limited to, transfusion risk index, phlebotomy techniques, management of hemostasis and hemoglobin levels which includes blood testing, pharmacologic agents, and blood transfusion prescription guidelines.

Can extra protamine eliminate heparin rebound following cardiopulmonary bypass surgery?

OBJECTIVES

Heparin rebound, the reappearance of anticoagulant activity after adequate neutralization with protamine, is thought to contribute to excessive postoperative bleeding after cardiac surgery. We have previously demonstrated that a significant amount of heparin is bound nonspecifically to plasma proteins and is incompletely neutralized by protamine. The aim of this study was to investigate whether clinically important bleeding attributable to heparin rebound can be eliminated by infusion of small amounts of additional protamine for 6 hours postoperatively and whether this treatment can reduce mediastinal blood loss.

METHODS

Three hundred patients undergoing elective cardiac surgery were randomized to receive either a continuous infusion of protamine sulphate (25 mg/h for 6 hours) postoperatively or saline placebo. Serial blood samples were obtained to measure thrombin clotting time and anti-factor Xa activity. Heparin bound nonspecifically to plasma proteins was measured after displacement with a chemically altered heparin with low affinity to antithrombin. Mediastinal blood loss and transfusion requirements were recorded.

RESULTS

Heparin rebound was demonstrated in every patient in the placebo group as reflected by increased thrombin clotting time, anti-factor Xa activity, and protein-bound heparin between 1 and 6 hours after surgery. In contrast, heparin rebound was eliminated in the protamine infusion group. The thrombin clotting time was normalized and both heparin concentration and protein-bound heparin were almost undetectable (P <.001). There was a modest 13% reduction in postoperative bleeding but this did not reduce blood transfusions. No adverse events were attributable to the extra protamine.

CONCLUSIONS

Postoperative protamine infusion was able to almost totally abolish heparin rebound. In the context of this study, protamine infusion resulted in reduced postoperative bleeding but the magnitude was insufficient to alter transfusion requirements.

Heparin and Low-Molecular-Weight Heparin

This article about unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) is part of the Seventh American College of Chest Physicians Conference on Antithrombotic and Thrombolytic Therapy: Evidence-Based Guidelines. UFH is a heterogeneous mixture of glycosaminoglycans that bind to antithrombin via a pentasaccharide, catalyzing the inactivation of thrombin and other clotting factors. UFH also binds endothelial cells, platelet factor 4, and platelets, leading to rather unpredictable pharmacokinetic and pharmacodynamic properties. Variability in activated partial thromboplastin time (aPTT) reagents necessitates site-specific validation of the aPTT therapeutic range in order to properly monitor UFH therapy. Lack of validation has been an oversight in many clinical trials comparing UFH to LMWH. In patients with apparent heparin resistance, anti-factor Xa monitoring may be superior to measurement of aPTT. LMWHs lack the nonspecific binding affinities of UFH, and, as a result, LMWH preparations have more predictable pharmacokinetic and pharmacodynamic properties. LMWHs have replaced UFH for most clinical indications for the following reasons: (1) these properties allow LMWHs to be administered subcutaneously, once daily without laboratory monitoring; and (2) the evidence from clinical trials that LMWH is as least as effective as and is safer than UFH. Several clinical issues regarding the use of LMWHs remain unanswered. These relate to the need for monitoring with an anti-factor Xa assay in patients with severe obesity or renal insufficiency. The therapeutic range for anti-factor Xa activity depends on the dosing interval. Anti-factor Xa monitoring is prudent when administering weight-based doses of LMWH to patients who weigh > 150 kg. It has been determined that UFH infusion is preferable to LMWH injection in patients with creatinine clearance of < 25 mL/min, until further data on therapeutic dosing of LMWHs in renal failure have been published. However, when administered in low doses prophylactically, LMWH is safe for therapy in patients with renal failure. Protamine may help to reverse bleeding related to LWMH, although anti-factor Xa activity is not fully normalized by protamine. The synthetic pentasaccharide fondaparinux is a promising new antithrombotic agent for the prevention and treatment of venous thromboembolism.

Dextran sulfate included in factor Xa assay reagent overestimates heparin activity in patients after heparin reversal by protamine

A lack of correlation between activated partial thromboplastin time (aPTT), thrombin time (TT) and anti-factor Xa (AXa) activity was observed in patients after cardiac surgery with cardiopulmonary bypass (CBP). Indeed, AXa activity measured by the chromogenic assay, Coamatic Heparin, was higher than expected with regard to results obtained in coagulation assays. To account for this discrepancy, another AXa chromogenic assay was tested. First, AXa activity was measured with two chromogenic assays (Coamatic Heparin and Rotachrom Heparin) in plasma samples of 25 patients undergoing cardiac surgery at two time points after heparin reversal by protamine. AXa activity was significantly higher when measured with Coamatic Heparin than with Rotachrom Heparin in samples collected just after protamine infusion (p<0.01). Next, since Coamatic( Heparin contains dextran sulfate (DXS) to reduce the influence of heparin antagonists such as platelet factor 4 (PF4), whereas Rotachrom Heparin does not, we hypothesized that the dextran sulfate contained in the reagent might explain this discrepancy. We therefore performed in vitro studies consisting in neutralizing unfractionated heparin (UFH) with protamine and measuring AXa activity with the two chromogenic assays. An AXa activity was still measurable with Coamatic Heparin after neutralization, thus strongly suggesting that dextran sulfate dissociates protamine/heparin complexes. We conclude that Coamatic Heparin assays should be avoided when measuring AXa activity in plasma samples immediately after protamine infusion, as inaccurate results may lead to inadequate management of heparin reversal.

Bivalirudin, Blood Loss, and Graft Patency in Coronary Artery Bypass Surgery

A safe and effective alternative is needed for patients in whom unfractionated heparin (UFH) or protamine is contraindicated (e.g., those with heparin-induced thrombocytopenia or allergy to protamine). Furthermore, choice of anticoagulant may influence graft patency in coronary surgery and may therefore be important even when there is no contraindication to UFH. Direct thrombin inhibitors have several potential advantages over UFH, demonstrated in acute coronary syndromes. However, there are also potential difficulties with their use related to lack of reversal agents and paucity of clinical experience in monitoring their anticoagulant activity at the levels required for cardiac surgery with cardiopulmonary bypass (CPB). In the first prospective randomized trial of an alternative to heparin in cardiac surgery, we compared bivalirudin (a short-acting direct thrombin inhibitor) with UFH in 100 patients undergoing off-pump coronary artery bypass (OPCAB) surgery. Blood loss for the 12 hours following study drug initiation in the bivalirudin group was not significantly greater than in the heparin group. Median graft flow was significantly higher in the bivalirudin group. We concluded that anticoagulation for OPCAB surgery with bivalirudin was feasible without a clinically important increase in perioperative blood loss. A larger study is needed to investigate the impact of improved graft patency on other clinical outcomes after cardiac surgery.

Intraoperative management: carotid endarterectomies

The management of anesthesia for patients undergoing carotid endarterectomy is challenging and dynamic. Effective management and good outcome requires the anesthesiologist's understanding of cerebral physiology, knowledge of neck anatomy, and understanding of the rapid pathophysiologic changes that occur during carotid artery manipulations. The anesthesiologist must be flexible in the management of patients, who frequently have underlying multiorgan pathology and cardiovascular compromise. Good communication between the anesthetic and surgical teams is needed to avoid irreversible debilitating consequences for the patient.

Incomplete Reversal of Enoxaparin Toxicity by Protamine: Implications of Renal Insufficiency, Obesity, and Low Molecular Weight Heparin Sulfate Content

The use of low molecular weight heparin (LMWH) is increasing throughout North America and Europe for a number of reasons: 1). ease of use; 2). predictable dose response; 3). less heparin associated thrombocytopenia. However, aside from increased costs, LMWH has significant potential drawbacks: 1). poor reversibility; 2). tendency to accumulate in renal insufficiency; 3). less experience in subset patient groups such as morbid obesity. We report a case of a postoperative morbidly obese patient who developed enoxaparin toxicity secondary to acute renal failure that did not reverse with protamine sulfate infusion. In addition, we review the use of LMWH in renal insufficiency, dosing in obese patients,and the importance of sulfate content in the efficacy of protamine sulfate as a reversing agent for LMWH.

Development of protamine hollow-fiber device for extracorporeal heparin removal

Protamine was covalently coupled to a cellulose hollow fiber (cuprophan membrane) through epichlorohydrin-activated hydroxyl groups on the hollow fiber. An immobilization efficiency of as much as 15 mg protamine/g fiber could be achieved under optimal reacting conditions. Compared to a protamine hollow-fiber device produced using cyanogen bromide as an activator, the protamine hollow-fiber device using epichlorohydrin as an activator shows very high resistance to hydrolysis. Both in vitro and in vivo experiments showed that such a protamine hollow-fiber device had high heparin-removal capacity and efficiency, suggesting that this device may be suitable for various clinical applications in extracorporeal heparin removal.

Prophylactic Treatment with Desmopressin Does Not Reduce Postoperative Bleeding After Coronary Surgery in Patients Treated with Aspirin Before Surgery

The synthetic vasopressin analog desmopressin has hemostatic properties and may reduce postoperative bleeding after coronary artery bypass grafting (CABG). A study on the effects of recent aspirin ingestion on platelet function in cardiac surgery showed a greater impairment of platelet function in patients treated with aspirin <2 days before the operation. We evaluated the effects of desmopressin on postoperative bleeding in CABG patients who were treated with aspirin 75 or 160 mg until the day before surgery. The study was a prospective, randomized, double-blinded, placebo-controlled, parallel group trial. One-hundred patients were included and divided into two groups. One group received desmopressin 0.3 micro g/kg and the other received placebo (0.9% NaCl) after the neutralization of heparin with protamine sulfate. Postoperative blood loss was recorded for 16 h. The mean (SD) bleeding was 606 (237) mL in the desmopressin group and 601 (301) mL in the placebo group (P = 0.93), representing no significant difference (95% confidence interval, -107 to 117 mL). We conclude that desmopressin does not reduce postoperative bleeding in CABG patients treated with aspirin until the day before surgery.

IMPLICATIONS

Continuation of aspirin until the day before coronary artery bypass grafting may increase postoperative bleeding. The administration of desmopressin to these patients after the neutralization of heparin with protamine sulfate does not reduce postoperative bleeding.

[Long-term application of percutaneous cardiopulmonary support system without systemic heparinization]

Though the amount of systemic heparin sodium administration was reduced after the introduction of heparin sodium-coating material to percutaneous cardiopulmonary support system (PCPS), bleeding due to heparin sodium is still the one of the major complications. In 2 patients of postcardiotomy cardiogenic shock, we neutralized heparin sodium by protamine sulfate administration immediately after the institution of PCPS and did not perform systemic heparinization until hemostasis was secured. The time on PCPS without heparin sodium was 37 hours in 1 patient and 91 hours in another patient. While systemic heparin sodium was not administered, activated clotting time (ACT) ranged from 109 to 148 sec and the bypass flow rate was maintained in more than 2.5 l/min. The exchange of the devices was unnecessary during the assistance and the patients were successfully weaned from PCPS without major complications. We conclude that systemic anticoagulation can be avoided in the case of life-threatening hemorrhage.

Incidence, correlates, management, and clinical outcome of coronary perforation: analysis of 16,298 procedures

BACKGROUND

Coronary perforation is a serious but uncommon complication of percutaneous coronary intervention (PCI) and is associated with significant morbidity and mortality.

METHODS

We performed an analysis of the Mayo Clinic PCI database. Clinical records, procedural reports, and angiographic studies were reviewed. Multiple logistic regression analysis was performed to identify clinical, procedural, anatomic, and angiographic correlates of coronary perforation.

RESULTS

A total of 16,298 PCI procedures were performed between January 1990 and December 2001. We identified 95 coronary perforations (0.58%; 95% CI, 0.47-0.71). The incidence of coronary perforation varied with time. Correlates of coronary perforation included the use of an atheroablative device and female sex. Twelve patients (12.6%) sustained an acute myocardial infarction, and cardiac tamponade developed in 11 patients (11.6%). Management strategies included reversal of heparin, pericardiocentesis, placement of a covered stent, and surgical repair. Seven patients died (7.4%).

CONCLUSIONS

Coronary perforation during PCI is rare, but is associated with significant morbidity and mortality. The variable frequency of perforation may be explained by temporal variations in the use of atheroablative devices.

Protamine enhances uptake of cationic liposomes in angiogenic microvessels of solid tumours

INTRODUCTION

Cationic liposomes have been shown to target angiogenic endothelial cells of solid tumours. Supposing a charge-related mechanism might be responsible for liposome-endothelial interaction, we investigated the effect of intravenous pre-injection of the charged molecules protamine, a polycationic protein, and fucoidan, a polyanionic polysaccharide on the accumulation of cationic liposomes within the blood vessels of a solid tumour.

MATERIALS AND METHODS

Experiments were performed using the amelanotic hamster melanoma A-Mel-3 growing in a dorsal skinfold chamber of hamsters. Accumulation of fluorescently-labelled cationic liposomes was quantified by intravital macroscopy and digital image analysis of tumour (t) and surrounding normal host tissue (n) over an observation period of 6 h. All animals received an i.v. injection of cationic liposomes. Animals of the control group were pre-treated with an i.v. injection of 0.9% saline, while animals of group 2 received positively charged protamine and animals of group 3 negatively charged fucoidan prior to liposome injection.

RESULTS

In control animals i.v. injection of cationic liposomes revealed a preferential targeting of the tumour vessels, indicated by a maximal t/n ratio of 2.2 +/- 0.24 and a maximal fluorescence intensity (fmax) corresponding to the tumour of 66 +/- 12 [% standard]. While there were no significant differences of liposome accumulation within normal host tissue, accumulation of cationic liposomes within the tumour was significantly enhanced after the pre-administration of protamine (fmax: 117 +/- 12 [% standard]). The t/n ratio was significantly increased in protamine pre-treated animals (5.3 +/- 1.7) in comparison to control and fucoidan treated animals. In contrast, pre-injection of fucoidan resulted in reduced maximal fluorescence intensities in tumour (47 +/- 8 [% standard]) and normal surrounding host tissue.

CONCLUSION

Pre-administration of protamine increases the accumulation of cationic liposomes in a solid tumour animal model causing an increased selectivity of cationic liposomes in targeting angiogenic microvessels.

Nucleoprotamine diet derived from salmon soft roe protects mouse hippocampal neurons from delayed cell death after transient forebrain ischemia

The nutritional benefits of nucleoprotamine (NP), the main component of fish soft roe, have been rarely addressed. In the present study, the preventive effect of oral supplements of nucleoprotamine and its derivatives, DNA and protamine (PT), extracted from salmon soft roe, on survival rate and hippocampal cell death induced by transient brain ischemia, was evaluated in mice. Artificially formulated nucleoprotamine-free (NF) diet with/without nucleoprotamine, DNA or protamine was fed orally. One week after commencement of respective diets, animals were subjected to transient brain ischemia, which was performed by common carotid artery (CCA) occlusion for 25 (severe) or 15 min (mild). After severe ischemia, the survival rate of the NF group was lower than that in the group fed standard diet or NP. Morphological changes in the hippocampal CA1 region were estimated 48 h after mild ischemia. The NP and PT groups significantly decreased the neuronal damage compared with the NF group. The number of cell death in the DNA group, however, was affected similar to that of the NF group. Our data suggests that the nucleoprotamine content in salmon soft roe could be a useful nutritional resource for the prevention of cell damage caused by ischemia such as those occurring with cerebral and/or heart infarction.

Loading the multilayer dextran sulfate/protamine microsized capsules with peroxidase

Stable polyelectrolyte capsules were produced by the layer-by-layer (LbL) assembling of biodegradable polyelectrolytes, dextran sulfate and protamine, on melamine formaldehyde (MF) microcores followed by the cores decomposition at low pH. The mean diameter of the capsules at pH 3-5 was 8.0 +/- 0.2 microm, which is more than that diameter of the templates (5.12 +/- 0.15 microm). With pH growing up to 7-8, the capsules enlarged, swelling up to the diameter 9-10 microm. The microcapsules were loaded with horseradish peroxidase. Seemingly, peroxidase is embedded in the gellike structure in the microcapsule interior formed by MF residues in the complex with polymers used for LbL coating as proved by Raman confocal spectroscopy. The amount of finally incorporated peroxidase increased from 0.2 x 10(8) to 2.2 x 10(8) peroxidase molecules per capsule with pH growing from 5 to 8. The pH shifts causing changes in capsule swelling and the replacement of solutions without pH shifts lead to the protein loss. The encapsulated peroxidase showed a high activity (57%), which remained stable for 12 months.

Evaluation of the effect of protamine on human prostate carcinoma PC-3m using contrast enhanced Doppler ultrasound

PURPOSE

We evaluated the ability of contrast enhanced Doppler ultrasound (CEDU) to demonstrate changes in tumor vascularity during angiogenesis inhibitive therapy in PC-3m human prostate carcinoma.

MATERIALS AND METHODS

Pieces of human prostate carcinoma PC-3m tumor (Institute of Urology, Beijing University, Beijing, People's Republic of China) were transplanted subcutaneously into 48 male BALB/C nude mice (Center of Animal Quarantine, Beijing, People's Republic of China). Protamine (Shanghai Biochemistry Pharmaceutical Co., People's Republic of China) was injected subcutaneously as an angiogenesis inhibitor. The animals were randomly divided into 3 groups according to protamine dose. The color flow signal-pixel rate (SPR) of the images was calculated using the number of pixels showing color Doppler signals as a ratio of the total number of pixels covering the lesion.

RESULTS

The SPR of the high and low dose groups were significantly lower than that of the control group (p <0.01). Mean SPR +/- SD in the 3 groups was 0.09 +/- 0.05, 0.11 +/- 0.05 and 0.22 +/- 0.10, respectively. SPR correlated significantly with microvessel density (r = 0.86 to 0.94, p <0.01).

CONCLUSIONS

CEDU can effectively reveal the change in vascularity in a tumor that was treated with protamine. In addition to microvessel density, CEDU may become one of several independent prognostic indexes of angiogenesis inhibitor therapy.

Low molecular weight protamine as an efficient and nontoxic gene carrier: in vitro study

BACKGROUND

The structural similarity between low molecular weight protamine (LMWP), prepared by enzymatic digestion of protamine, and HIV-TAT protein transduction peptide suggested the feasibility of LMWP as an efficient carrier for delivering therapeutic genes while alleviating the cytotoxicity of currently employed gene carriers.

METHODS

LMWP was prepared by enzymatic digestion of protamine with thermolysine. The prepared LMWP peptide and TAT peptide, as well as their complexes with plasmid DNA (pDNA), were examined for cellular uptake behaviors by using confocal microscopy and flow cytometry. The complexation of pDNA and LMWP was monitored by gel retardation test as well as size and zeta potential measurements, and was then further assessed by DNase I protection assay. The transfection efficiency of pDNA/LMWP was examined by varying the pDNA content and charge ratio in the complex, and then compared with that of pDNA/PEI. Cytotoxicity induced by pDNA/LMWP and pDNA/PEI was also examined.

RESULTS

Prepared LMWP showed similar transcellular localization behavior and kinetics to those of TAT, and efficiently transferred the pDNA into nucleus and cytoplasm in a short time period. The size and zeta potential of the pDNA/LMWP complex were 120 nm and 30 mV, respectively, which were adequately suitable for cellular uptake. After forming the complex, LMWP appeared to effectively protect pDNA against DNase I attack. The pDNA/LMWP complex showed significantly enhanced gene transfer than both naked pDNA and the pDNA/PEI complex, while exhibiting a markedly reduced cytotoxicity than that of the pDNA/PEI complex.

CONCLUSIONS

The present study suggested that LMWP could be a useful and safe tool for enhancing delivery of bioactive molecules and therapeutic DNA products into cells when applied in gene therapy.

Continuous renal replacement therapies: anticoagulation in the critically ill at high risk of bleeding

BACKGROUND

The ongoing necessity for systemic heparinization is a well-known disadvantage of continuous renal replacement therapies (CRRT), and alternative methods of anticoagulation may be required. Our aim was to evaluate, in patients with a high risk of bleeding, the possibility of an acceptable filter life with non-anticoagulation CRRT and, in case of early filter failure, the efficacy and safety of bedside monitored regional anticoagulation with heparin and protamine.

METHODS

Fifty-nine patients underwent CRRT for acute renal failure (ARF) following cardiac surgery. Patients who fulfilled one of the following criteria were selected for non-anticoagulation CRRT: spontaneous bleeding, aPTT > 45 sec, thrombocytopenia and recent surgery (< 48 hr). Filter life < 24 hr without anticoagulation was the cut-off point for starting the regional anticoagulation CRRT. Heparin was infused pre-filter and protamine post-filter at an initial ratio of 1 mg protamine:100 IU heparin. The ratio was adjusted to achieve a patient aPTT < 45 sec and a circuit > 55 sec.

RESULTS

Twenty-two (37.3%) patients had been selected for non-anticoagulation. Of them, 12 patients continued to receive non-anticoagulation (filter life: 38.3 +/- 30.5 hr) while 10 switched to regional anticoagulation (filter life: 38.6 +/- 25 hr). During regional anticoagulation no statistical difference was found between baseline aPTT (36.7 +/- 6.4 sec) and patient aPTT (41.5 +/- 12.6 sec) while circuit aPTT (77.7 +/- 43.3 sec) was significantly higher than patient aPTT (p < 0.0001). The probabilities of the circuits remaining free from clotting after 24, 48 and 72 hr were: a) non-anticoagulation: 55.5%, 30.1% and 16.6%, b) regional anticoagulation: 76.2%, 39.6% and 19.8%. There was no rebound anticoagulation observed after regional anticoagulation CRRT ended.

CONCLUSIONS

Non-anticoagulation CRRT allowed an adequate filter life in most patients with a high risk of bleeding for prolonged aPTT and/or thrombocytopenia. Despite concerns regarding the need for careful monitoring, regional anticoagulation with heparin and protamine can be considered as a safe and valid alternative when non-anticoagulation is unsuitable because of early filter failure.

Single-dose tranexamic acid reduces postoperative bleeding after coronary surgery in patients treated with aspirin until surgery

Tranexamic acid reduces postoperative bleeding after coronary artery bypass grafting. We evaluated the effects of a single dose of tranexamic acid given immediately before cardiopulmonary bypass (CPB) in patients treated with aspirin until the day before surgery. The study was a prospective, randomized, double-blinded, placebo-controlled, parallel-group trial. Eighty patients were included and divided into two groups: one group received tranexamic acid 30 mg/kg, and one group received placebo (0.9% NaCl) as a bolus injection before CPB. Postoperative blood loss was recorded for 16 h. Transfusions of blood products were recorded for the whole hospital stay. Transfusions of packed red cells were given when the hematocrit value was less than 20% during CPB and less than 25% after surgery. The patients in the tranexamic acid group had significantly less postoperative bleeding compared with the patients in the placebo group (mean [SD]) (475 [274] mL versus 713 [243] mL; P < 0.001). An effective inhibition of fibrinolysis was found in patients receiving tranexamic acid. Tranexamic acid reduces postoperative bleeding in coronary artery bypass grafting patients treated with aspirin until the day before surgery.

IMPLICATIONS

Continuation of aspirin medication until the day before coronary artery bypass grafting may increase postoperative bleeding. The administration of a single dose of tranexamic acid (30 mg/kg) immediately before cardiopulmonary bypass significantly reduced postoperative bleeding and inhibited fibrinolysis in these patients.

The use of specific antidotes as a response to bleeding complications during anticoagulant therapy for venous thromboembolism

When a bleeding complication occurs during therapy with heparin or vitamin K antagonists, there is an option to give a specific antidote. Several new anticoagulants have been developed that are likely to have some risk of bleeding complications, for which no specific antidotes are available. Interestingly, it is unknown how often the use of an antidote is necessary in clinical practice. We investigated 1877 patients treated for venous thromboembolism included in three large clinical trials, of which 181 (9.6%) had a total of 225 adjudicated bleeding episodes; 46 hemorrhages being designated as major. Some form of antidote was given to 26 (14.4%) patients with a hemorrhage. Of the patients with at least one major hemorrhage, 19 (41.3%) received an antidote. Vitamin K was given to 23 (1.2%) patients, one (0.05%) patient received protamin sulfate and seven (0.4%) patients received fresh frozen plasma. The use of antidotes was comparable for initial and long-term treatment. Antidotes were statistically significantly more frequently given in Canada as compared to other participating countries. Vitamin K was more frequently given in case of a higher international normalized ratio value. Although antidotes against anticoagulant treatment are widely available, our analysis shows that in only a very small number of patients a direct, or slow-acting antidote to reverse the anticoagulant effect was used.

Heparin reversal in off-pump coronary artery bypass surgery: complete, partial, or no reversal?

Several clinical studies have reported that avoiding cardiopulmonary bypass reduces postoperative bleeding. The purpose of this study is to verify that protamine during off-pump coronary artery bypass surgery produces significant reduction of postoperative bleeding. Sixty consecutive patients undergoing off-pump coronary artery bypass surgery were prospectively randomized in three groups: Group A received 1 mg of protamine every 100 IU of heparin, Group B 0.5 mg of protamine every 100 IU of heparin, and Group C none. The three groups were analyzed for differences in preoperative cardiac function, pre-, intra-, and postoperative coagulation profile, intraoperative variables, and postoperative bleeding. In the three study groups, no statistically significant difference was found in preoperative cardiac function, pre- and intraoperative coagulation profile, and prothrombin time, activated partial thromboplastin time, platelet count in the first postoperative day. In Group A, total postoperative bleeding, use of packed red blood cells, and mild pericardial effusion prevalence at discharge were significantly lower only when compared to Group C, but they were not significantly different when compared to Group B. In off-pump coronary artery bypass surgery, heparin should be reverted with protamine, otherwise the postoperative bleeding risk might increase. Partial heparin reversal might not increase postoperative bleeding risk, but it may reduce dose-dependent protamine adverse effects.

Assessment of protamine-induced thrombosis of tumor vessels for cancer therapy using dynamic contrast-enhanced MRI

Since the role of angiogenesis in cancer development has been recognized, the study of anti-angiogenic or anti-vascular therapeutic agents has become increasingly important for cancer treatment. Selective thrombosis is one approach towards this goal. Since many types of carcinoma accumulate large numbers of degranulating mast cells which will release heparin, intravenously injected protamine may bind to heparin, neutralize its anti-coagulant effect and induce thrombosis. In this work we studied the formation of thrombosis by using dynamic contrast enhanced MRI. The enhancement kinetics of the contrast medium measured before and after protamine treatment were compared to assess the thrombotic effect. The underlying concept was that if the vessels became clotted, the subsequently injected contrast medium could not be delivered into the tissue to cause enhancement. In addition to the tissue-specific changes, protamine may also induce systemic effect in the host. The therapy-induced changes measured in tumors were compared to changes in normal tissues: liver, kidney, and especially the muscle adjacent to tumor. The results showed that protamine induced pronounced changes in the tumor. However, the degree of change measured by MRI was not associated with the results of semiquantitative assessment of thrombosis assessed by histology, perhaps due to the heterogeneous nature of the tumor and the difficulty in sampling sufficient regions histologically. The protamine-induced temporal effects were also studied. We demonstrated that protamine could induce selective thrombosis in tumors, and that the effect could last for several hours. Dynamic contrast-enhanced MRI can serve as a suitable means to investigate the mechanism of this novel approach to induce selective thrombosis for anti-vascular cancer therapy.

Anticoagulation therapy in acute renal failure extracorporeal treated patients

In extracorporeal techniques, as used for Acute Renal Failure (ARF) treatments, blood is constantly exposed to foreign surfaces. These foreign surfaces include the catheter(s), blood tubings, the dialyser membrane and all artificial materials used for such techniques in general. Blood begins to clot as soon as it strikes a foreign surface. The foreign surface initiates the clotting process. The extracorporeal circuit is prone to clotting during acute treatments unless some form of anticoagulation is employed. On the other hand, this specific group of patients is often at increased risk of bleeding (cfr. Post-operative patients and post-renal-transplant patients, patients with Multiple Organ Failure (MOF) often including liver disturbances). It should be kept in mind that patients with renal failure have a defect in platelet function resulting in altered platelet-vessel wall interaction. Over time, as the extracorporeal treatment progresses, the platelets become more adhesive or sticky. The blood becomes more likely to clot. Performing effective therapy with low bleeding risk in ARF patients is a challenge requiring knowledge, skills and experience.

Effects of a fixed mixture of 25% insulin lispro and 75% NPL on plasma glucose during and after moderate physical exercise in patients with type 2 diabetes

OBJECTIVE

To compare the plasma glucose (PG) response with a fixed mixture of 25% insulin lispro and 75% NPL (Mix25), prior to a meal and 3 h before exercise, to human insulin 30/70 (30/70) in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Thirty-seven patients were treated in a randomized, open-label, 8-week, two-period crossover study. Mix25 was injected 5 min before breakfast and dinner throughout the study, as was 30/70 on inpatient test days and on outpatient dose titration days. Following the 4-week outpatient phase, patients were hospitalized, and exercised at a heart rate of 120 beats/min on a cycle ergometer two times for 30 min, separated by 30 min rest, starting 3 h after a 339 kcal breakfast.

RESULTS

The 2-h postprandial PG was significantly lower with Mix25 ((mean +/- SEM) 10.5 +/- 0.4 mmol/l vs 11.6 +/- 0.4 mmol/l; p = 0.016). Maximum decrease in PG from onset of exercise to end of exercise was significantly less with Mix25 (-3.6 +/- 0.29 mmol/l vs -4.7 +/- 0.31 mmol/l; p = 0.001). The maximum decrease in PG over 6 h, after exercise onset, was significantly less with Mix25 (-4.3 +/- 0.4 mmol/l vs -5.9 +/- 0.4 mmol/l; p < 0.001). The frequency of hypoglycemia (blood glucose (BG) < 3 mmol/l or symptoms) during the inpatient test was not different between treatments. During the outpatient phase, the frequency of patient-recorded hypoglycemia was significantly lower with Mix25 (0.7 +/- 0.2 episodes/30 d vs 1.2 +/- 0.3 episodes/30 d; p = 0.042).

CONCLUSIONS

Mix25 resulted in better postprandial PG control without an increase in exercise-induced hypoglycemia. The smaller decrease in PG during the postprandial phase after exercise may suggest a lower risk of exercise-induced hypoglycemia with Mix25 than with human insulin 30/70, especially for patients in tight glycemic control.

Life threatening cardiopulmonary failure in an infant following protamine reversal of heparin after cardiopulmonary bypass

Life threatening cardiopulmonary failure following protamine reversal of heparin after cardiopulmonary bypass (CPB) was reported to occur in adults but rarely in children. Atrial septal defect closure was performed in a 6-week-old infant erroneously suspected to suffer from right atrial thrombosis in addition. Protamine administration after CPB led to critical pulmonary hypertension and severe haemorrhagic pulmonary oedema resulting in severe hypoxia. Inhaled nitric oxide, together with high frequency oscillation ventilation supplemented by intravenous prostacycline, enabled complete recovery of cardiopulmonary and neurological function. Life threatening cardiovascular compromise after intravenous protamine can occur even in young infants which then require challenging paediatric critical care.

Alternatives to unfractionated heparin for anticoagulation in cardiopulmonary bypass

Despite the progress made in the development of cardiopulmonary bypass (CPB) equipment, systemic anticoagulation with unfractionated heparin and post-bypass neutralization with protamine are still used in most perfusion procedures. However, there are a number of situations where unfractionated heparin, protamine or both cannot be used for various reasons. Intolerance of protamine can be addressed with extracorporeal heparin removal devices, perfusion with (no) low systemic heparinization and, to some degree, by perfusion with alternative anticoagulants. Various alternative anticoagulation regimens have been used in cases of intolerance to unfractionated heparin, including extreme hemodilution, low molecular weight heparins, danaparoid, ancrod, r-hirudin, abciximab, tirofiban, argatroban and others. In the presence of heparin-induced thrombocytopenia (HIT) and thrombosis, the use of r-hirudin appears to be an acceptable solution which has been well studied. The main issue with r-hirudin is the difficulty in monitoring its activity during CPB, despite the fact that ecarin coagulation time assessment is now available. A more recent approach is based on selective blockage of platelet aggregation by means of monoclonal antibodies directed to GPIIb/IIIa receptors (abciximab) or the use of a GPIIb/IIIa inhibitor (tirofiban). An 80% blockage of the GPIIb/IIIa receptors and suppression of platelet aggregation to less than 20% allows the giving of unfractionated heparin and running CPB in a standard fashion despite HIT and thrombosis. Likewise, at the end of the procedure, unfractionated heparin is neutralized with protamine as usual and donor platelets are transfused if necessary. GPIIb/IIIa inhibitors are frequently used in interventional cardiology and, therefore, are available in most hospitals.

Evaluation of post-cardiopulmonary bypass coagulation disorders by differential diagnosis with a multichannel modified thromboelastogram: a pilot investigation

We assessed a modified multichannel thromboelastogram for differentiation of the causes of coagulopathy after cardiopulmonary bypass and its suitability as a therapy guide. Thirty adult patients undergoing surgery with cardiopulmonary bypass, who revealed a coagulopathy as observed by a prolonged activated clotting time of >150 sec after the application of protamine, were enrolled. Therapy was based on the results obtained by the computerized four-channel thromboelastogram with baseline, heparinase (2 IU/mL), heparinase/abciximab (5 microg/mL), and heparinase/fresh frozen plasma (25%) channels. The mean activated clotting time before therapy was 162.2+/-7.8 sec. Based on differential diagnosis with the modified multichannel thromboelastogram, two patients received protamine (30 mg), five desmopressin (0.4 microg/kg), 19 patients three units of fresh frozen plasma, two patients platelet transfusions, and two patients both protamine (30 mg) and three units of fresh frozen plasma. After therapy, there was a significant (p < .01) decrease of the activated clotting time to a mean value of 127+/-8.3 sec. Therapy based on the synoptic modified multichannel thromboelastogram analysis provides a guide for effective therapy of coagulopathy. However, elaboration is desirable, and larger clinical trials are necessary for a final evaluation of the protocol.

Clinical use of heparin-coated cardiopulmonary bypass in coronary artery bypass grafting

Clinical handling, risk and benefit of a heparin-coated cardiopulmonary bypass system combined with reduced systemic heparinization in coronary bypass surgery was investigated in a prospective, randomized clinical study. 243 patients (Pts.) were divided into 3 groups: group A (n = 83) had a standard uncoated extracorporeal circulation (ECC) set, and systemic heparin was administered in an initial dose of 400 IE/kg body weight. During ECC activated clotting time (ACT) was kept > or = 480 sec. Group B (n = 77) had the same ECC set completely coated with low-molecular-weight heparin; i.v. heparin was given in the same dose as in group A, ACT was kept at the same level. Group C (n = 83) had the same coated ECC set as group B, but i.v. heparin was reduced to 150 IE/kg, and was set to be > or = 240 sec during ECC ACT. The same circulatory components were used in all 3 groups including roller pumps, coronary suction and an open cardiotomy reservoir. In the postoperative clinical course, recovery was not significantly different between groups, especially with respect to organ dysfunction; but there was significantly reduced postoperative bleeding where heparin-coated ECC and low-dose systemic heparinization were both used. This circulatory technique was also associated with a distinctly lower need for postoperative blood replacement. We conclude that heparin-coated extracorporeal circulation combined with either full-dose or reduced systemic heparinization can be used effectively with the same standard equipment and procedures as in uncoated technology. Combination with low-dose i.v. heparin leads to significantly decreased blood loss and less need for blood replacement.

[Use of Organon, a synthetic heparinoid, in two cardiopulmonary bypass procedures in the same patient sensitive to heparin]

We report the case of a patient who underwent two cardiopulmonary bypass (CPB) procedures with Orgaran because of heparin-induced thrombocytopenia. A 38 years-old man with ischemic mitral insufficiency was operated for coronary artery bypass and valvular replacement. The CPB was carried out with heparin. Heparin-induced thrombocytopenia occured and was proven immunologically. Two months later, a new valvular replacement was performed because of paravalvular leak due to endocarditis. The Orgaran-CPB protocol was as follows: 5,000 units before cardiopulmonary bypass, 5,000 units in the priming volume, anti-Xa level between 0.9 and 1.1 units/mL, with injection of 1,500 units if necessary, no administration of protamine. One month later, a new valvular replacement was necessary and performed with the same protocol using Orgaran. No bleeding or thrombotic complication occurred. Orgaran is a safe and reliable anti-thrombotic substitute if anti-Xa activity is closely monitored.

The economic value of a new insulin preparation, Humalog Mix 25. Measured by a willingness-to-pay approach

OBJECTIVE

To measure the economic value of a new insulin formulation consisting of rapid-acting insulin lispro and intermediate-acting neutral protamine lispro in a 25:75 ratio (Humalog Mix 25).

DESIGN AND SETTING

A cost-benefit analysis using a consumer-based willingness-to-pay (WTP) approach was used. The study sample consisted of 80 Canadian taxpayers randomly selected from Ontario and Quebec. After background information on the differences between Humalog Mix 25 and human 30/70 insulin were presented, respondents were asked what their preferred product would be if they were diagnosed with diabetes mellitus. Respondents were then asked the maximum premium that they would pay per month in the form of a user's fee for the insulin of their choice.

STUDY PERSPECTIVE

Canadian taxpayer perspective.

MAIN OUTCOME MEASURES AND RESULTS

The WTP survey instrument was simple to administer and easily understood by participants. Approximately 84% of the sample of taxpayers preferred to use Humalog Mix 25 rather than human 30/70 insulin and were willing to pay for it (p = 0.012). They were willing to pay a mean of $Can35.28 [95% confidence interval (CI): $Can27.50 to $Can43.07] per month for the benefits offered by Humalog Mix 25, which was at least 2-fold higher than the incremental monthly cost of the drug (1999 values).

CONCLUSIONS

The results of the study revealed that Canadians prefer to use Humalog Mix 25 instead of human 30/70 insulin, and they would be willing to pay for it. Compared with other drugs, this overall net gain suggests that Humalog Mix 25 represents good value for money and should be considered for reimbursement by government formularies and other third-party payers.

Effect of glucagon on glucose production, lipolysis, and gluconeogenesis in familial hyperinsulinism

We present an infant with severe familial hyperinsulinism in whom glucose production rate, lipolysis, and gluconeogenesis from glycerol were measured by use of glucose and glycerol labelled with stable isotopes. Administration of a single dose of glucagon (0.1 mg/kg) caused an increase in glucose production rate by near 140% from 4.2 to 10.1 mg.kg-1.min-1. The rate of appearance of glycerol, reflecting the rate of lipolysis, decreased from 15.1 to 12.6 micromol. kg-1.min-1. The amount of glycerol converted to glucose by gluconeogenesis was 9.1 micromol.kg-1.min-1 before and 10.5 micromol. kg-1.min-1 after glucagon administration. We conclude that the marked rise in glucose production rate was mainly the result of increased glycogenolysis. Following the trial, the child was started on long-acting (zinc-protamine) glucagon which made it possible to discontinue intravenous treatment with glucose.

Hemostatic effects of low-dose protamine following cardiopulmonary bypass

Twenty-eight patients undergoing cardiac surgery were prospectively studied and were assigned to two groups. The patients received 0.8- (Group L) or 2.0-fold (Group H) dose of protamine for the neutralization after cardiopulmonary bypass (CPB) which was determined by Hepcon HMS(R) assay system in which the reagent chamber containing the concentration of protamine that completely neutralized the heparin had the shortest clotting time. Mean dose of protamine was 1.60 +/- 0.50 mg kg(-1) in Group L, and 3.56 +/- 1.48 mg kg(-1), respectively. Activated clotting times (ACT) were comparable between the two groups through this study period. In Group H, platelet counts significantly decreased to 69% of that before protamine administration, and plasma platelet factor 4 level significantly increased to approximate 2-fold of that before protamine administration just after protamine administration, respectively. However, these phenomena were not observed in Group L. In addition, these hemostatic changes occurred transiently just after protamine administration. We conclude that the low-dose protamine may prevent transient platelet depletion following CPB. Low-dose protamine can neutralize anticoagulation effect of heparin sufficiently and may mitigate protamine-induced platelet dysfunction.

Optimized basal-bolus therapy using a fixed mixture of 75% lispro and 25% NPL insulin in type 1 diabetes patients: no favorable effects on glycemic control, physiological responses to hypoglycemia, well-being, or treatment satisfaction

OBJECTIVE

To investigate the effects of a multiple injection regimen with a mixture of 75% lispro and 25% intermediate-acting insulin (lispro high mixture [HM]) before meals on glycemic control, physiological responses to hypoglycemia, well-being, and treatment satisfaction.

RESEARCH DESIGN AND METHODS

We studied 35 type 1 diabetes patients. After an 8- to 10-week lead-in period, patients were randomized to HM or human regular insulin therapy for 12-14 weeks. During the lead-in and treatment periods, HbA1c levels and hypoglycemic frequencies were measured, and patients completed the Well-Being Questionnaire and the Diabetes Treatment Satisfaction Questionnaire. In 19 patients, responses to hypoglycemia were tested during stepped euglycemic-hypoglycemic clamps.

RESULTS

HM treatment improved postprandial glycemia but had no effect on HbA1c, frequency of hypoglycemia, well-being, or treatment satisfaction. During experimental hypoglycemia, HM therapy was associated with a slightly lower total adrenaline response and a higher autonomic symptom threshold (i.e., the autonomic symptom response occurred at a lower blood glucose level) than human regular insulin therapy. We speculate that this effect resulted from an accumulation of insulin during the night.

CONCLUSIONS

Multiple injection therapy with HM rather than human regular insulin before meals does not offer advantages regarding glycemic control, frequency of hypoglycemia, well-being, or treatment satisfaction. In addition, this regimen causes an attenuation of the adrenaline and autonomic symptom responses to hypoglycemia.

Early mobilization after protamine reversal of heparin following implantation of phosphorylcholine-coated stents in totally occluded coronary arteries

Immediate removal of the femoral artery sheath after coronary angioplasty may allow rapid mobilization and reduces the number of in-hospital days. We studied the early and 1-month clinical and angiographic follow-up of patients having heparin reversed with protamine after implantation of phosphorylcholine-coated metal (Divysio) stents, followed by removal of the femoral artery sheath. Fifty patients (37 men, mean age 59 +/- 10 years) with stable angina pectoris and a single totally occluded artery (1 unprotected left main stem, 15 left anterior descending, 11 left circumflex, 23 right) underwent coronary angioplasty. Antithrombotic medication was salicylic acid 75 to 160 mg before, heparin bolus 7,500 IU during, and protamine sulfate 25 mg and oral ticlopidine 250 mg after the procedure. Angiography was performed after 30 minutes and at 1 month. The mean number of stents was 1.4 +/- 0.6/lesion, with a mean final diameter of 2.69 +/- 0.40 mm. One stent thrombus was detected after 30 minutes and was treated with balloon dilatation. One patient underwent emergency bypass surgery for non-stent-related problems. Forty-six patients were mobile after 5 hours, and 2 after >5 hours. At 1 month there had been no major coronary end points, rehospitalizations, groin bleeding, or more thrombi. One episode of transient pulmonary edema occurred after protamine injection. Thirty-eight patients (79%) had no angina at 1 month, maximal bicycle exercise capacity increased from 128 +/- 42 to 160 +/- 45 W (p <0.05), and left ventricular ejection fraction increased from 63% to 68% (p <0.05). Thus, reversal of heparin with protamine sulfate after implantation of a phosphorylcholine-coated stent enables early mobilization. This approach seems safe in patients with 1 -vessel total occlusions and angioplasty could be performed as an outpatient procedure.

Improved postprandial glycemic control with Humalog Mix75/25 after a standard test meal in patients with type 2 diabetes mellitus

OBJECTIVE

This double-blind study was designed to compare the postprandial glucodynamic profile of Humalog Mix75/25, a new premixed insulin analogue containing 75% neutral protamine lispro and 25% insulin lispro with that of human insulin 70/30 (70% neutral protamine Hagedorn insulin and 30% regular human insulin) in patients with type 2 diabetes mellitus.

BACKGROUND

Insulin lispro Mix75/25 (Mix75/25) is the first available insulin formulation in which both the rapid-acting and basal components are insulin analogues.

METHODS

This randomized, multicenter, double-blind, crossover study monitored patients' postprandial glucodynamic response to Mix75/25 and human insulin 70/30 (70/30) after a standard test meal. Eighty-four patients with type 2 diabetes participated in this study and were randomly assigned to 1 of 2 treatment sequence groups. Patients received an identical test meal on 4 occasions, completing 2 test meals for each treatment. Equal doses of Mix75/25 or 70/30 were administered 5 minutes before each of the 2 test meals, with doses individualized for each patient. Blood samples were collected for 4 hours after the meal for measurement of plasma glucose. From these plasma glucose measurements, fasting plasma glucose, 2-hour postprandial glucose (2pp), 2-hour postprandial glucose excursion (2pp(ex)), maximum glucose excursion (Gex(max)), the area under the glucose concentration versus time curve from 0 to 4 hours (AUC4), and the area under the glucose excursion versus time curve from 0 to 4 hours (AUCex4) were calculated.

RESULTS

Because of significant differences in the baseline fasting plasma glucose levels between Mix75/25 and 70/30 (Mix75/25: 8.9+/-2.2 mmol/L [160.2+/-39.6 mg/dL]; 70/30: 8.6+/-1.9 mmol/L [154+/-34 mg/dL), analyses of the excursion parameters provide a truer comparison of the glucodynamic response between insulin formulations. Mix75/25 resulted in significantly lower values for 2pp(ex) (3.35+/-2.28 vs 4.13+/-2.26 mmol/L), Gex(max) (4.51+/-1.88 vs 5.19+/-1.98 mmol/L), and AUCex4 (8.01+/-7.02 vs 10.6+/-6.47 mmol x h/L) compared with 70/30.

CONCLUSIONS

In patients with type 2 diabetes mellitus, premeal injection of Mix75/25 resulted in better postprandial glycemic control than did premeal injection of 70/30 in the 4 hours after a standard meal. Mix75/25 is a valuable option for managing postprandial blood glucose in patients with type 2 diabetes mellitus who require insulin.

Intraoperative echocardiographic detection of regurgitant jets after valve replacement

BACKGROUND

Paravalvular jets, documented by intraoperative transesophageal echocardiography, have prompted immediate valve explantation by others, yet the significance of these jets is unknown.

METHODS

Twenty-seven patients had intraoperative transesophageal two-dimensional color Doppler echocardiography, performed to assess the number and area of regurgitant jets after valve replacement, before and after protamine. Patients were grouped by first time versus redo operation, valve position and type.

RESULTS

Before protamine, 55 jets were identified (2.04+/-1.4 per patient) versus 29 jets after (1.07+/-1.2 per patient, p = 0.0002). Total jet area improved from 2.0+/-2.2 cm2 to 0.86+/-1.7 cm2 with protamine (p<0.0001). In all patients jet area decreased (average decrease, 70.7%+/-27.0%). First time and redo operations had similar improvements in jet number and area (both p>0.6). Furthermore, mitral and mechanical valves each had more jets and overall greater jet area when compared to aortic and tissue valves, respectively.

CONCLUSIONS

Following valve replacement, multiple jets are detected by intraoperative transesophageal echocardiography. They are more common and larger in the mitral position and with mechanical valves. Improvement occurs with reversal of anticoagulation.