A comparison of the haemostatic effect of Vivostat patient-derived fibrin sealant with oxidised cellulose (Surgicel) in multiple surgical procedures.

AIM: To evaluate the haemostatic properties of Vivostat patient-derived fibrin sealant in a broad range of surgical procedures. METHOD: In a prospective, randomised, multicentre, clinical study, typical surgical wounds of 69 patients (cardiothoracic, general, obstetric and gynaecologic, and vascular), requiring intervention to control bleeding, were treated with either Vivostat-derived sealant (n = 35) or Surgicel (n = 34) as required and the time taken to arrest bleeding was assessed. RESULTS: Compared with Surgicel, the mean time to haemostasis of Vivostat-derived sealant was significantly shorter (1.6 vs. 3.3 min, p < 0.0001) and more patients were successfully treated (i.e. no additional haemostatic measures required; 94 vs. 65%, p = 0.003). CONCLUSION: Vivostat-derived sealant is a more reliable and rapidly effective surgical haemostat than Surgicel.

Suture support: is it advantageous?

Sutures have been used to facilitate and enhance wound closure and healing throughout the course of medical history. Suturing is still the most common method of wound closure, but in some surgical situations suture support can improve clinical outcomes. Sutures provide mechanical support to a wound and help create the optimal environment for wound healing. However, suturing can give rise to such complications as bleeding from suture holes and air and fluid leakage. In the last 25 years, fibrin sealants have been used increasingly in the clinical setting to assist in the sealing of surgical wounds and to give additional mechanical support to a range of wounds during the early phases of wound healing. The use of fibrin sealants in addition to sutures has a direct effect on hemostasis and blood loss. Fibrin sealants also reduce the volume of fluid drained and air leakage postoperatively in head, neck, and thoracic surgery, in some cases resulting in a reduced length of hospital stay. The use of fibrin sealant as suture support can also reduce the number of sutures and the length of operations for intricate or complex procedures. The aim of this article is to provide an overview of how fibrin sealants acting as an adjunct to sutures affect surgical outcomes.

Bleeding from the sternal marrow can be stopped using vivostat patient-derived fibrin sealant.

BACKGROUND: Median sternotomy is the most important method of access to the heart. Bleeding from the sternal marrow may become significant, especially in elderly patients. Vivostat (ConvaTec, a Bristol-Myers Squibb Company, Skillman, NJ) patient-derived fibrin sealant is biocompatible and easily applied to the sternal marrow using the Vivostat Spraypen applicator. METHODS: Thirty patients undergoing elective cardiac operation were randomized to receive Vivostat fibrin sealant applied to either the right or left side of the sternum immediately after median sternotomy, with the untreated side serving as control. RESULTS: The average time to hemostasis was 43 seconds after treatment with Vivostat and 180 seconds on the control sides (p<0.001). At the end of the operation, complete hemostasis was observed on 24 of 30 sides treated with Vivostat compared with on 4 of 30 of the control sides (p<0.001). The average volume of sealant used to cover one side of the sternum was 0.9 mL. CONCLUSIONS: Vivostat patient-derived fibrin sealant is a biocompatible alternative to bone wax, with the results of this study showing that it provides effective control of bleeding after median sternotomy.

Prevention of air leakage by spraying vivostat fibrin sealant after lung resection in pigs.

STUDY OBJECTIVES: To evaluate Vivostat fibrin sealant in the prevention of air leakage after experimental lung resection in pigs. DESIGN: Randomized study. SETTING: University laboratory. METHODS: Six Landrace pigs were operated on in both lungs through a median sternotomy. Five different resection sites were created in each lung. INTERVENTION: Randomization was performed to either application of Vivostat fibrin sealant (ConvaTec; Skillman NJ) or human albumin 20% (control) at the resection sites. The lung parenchyma was occluded with a soft clamp for either 1, 2, 5, or 10 min in the treatment group and 10 min in the control group. After removal of the clamp, the lung was ventilated with an increasing intrabronchial pressure of 20, 30, and 45 cm H(2)O for 2 min at each step. RESULTS: At inspiratory pressures of 20 and 30 cm H(2)O air leaks were found in the control group but not in the Vivostat group (p < 0.001). At an inspiratory pressure of 45 cm H(2)O, there were two small air leaks in the Vivostat group at each clamping time (four at 5 min), compared with five small and seven large leaks in the control group. Analysis of the data after 10 min of clamping showed that the Vivostat group was superior to the human albumin group (p = 0.002). CONCLUSIONS: This randomized study shows that Vivostat fibrin sealant is effective in preventing air leakage after small lung resections in pigs, even at high inspiratory pressures.

Comparative kinetics of polymerisation of three fibrin sealants and influence on timing of tissue adhesion.

The clinical performance of fibrin sealants may be influenced by physical properties such as elasticity, tensile strength, and ability to adhere to human tissue. These properties are related to the internal structure of the fibrin sealant that builds as it polymerises. Analysis of the minimum polymerisation time to achieve a functional fibrin clot is clinically important. Instant tissue-fibrin sealant adhesion is desirable to ensure that the fibrin sealant functions on contact and remains at the site of application without being washed away by blood or displaced by movement of the target tissue (e.g., the heart or lungs). The physical characteristics of fibrin sealants are related to the extent of fibrin cross-linking. Determination of the polymerisation rate allows calculation of the minimum time required to produce a functional clot. The adhesion characteristics to vital human tissue and kinetics of polymerisation between 20 and 300 seconds postapplication of Vivostat system patient-derived sealant have been analysed and compared to those obtained for two conventional fibrin sealants, Tissucol and Beriplast. Mathematical analysis of the experimental data revealed that polymerisation of Vivostat sealant followed first-order kinetics, whereas that of Beriplast and Tissucol followed second-order kinetics. This study demonstrates that Vivostat sealant polymerises faster than these other conventional fibrin sealants.

Severe impairment of graft flow without electrocardiographic changes during coronary artery bypass grafting.

Early graft occlusion after coronary artery bypass grafting may have deleterious consequences. We routinely use transit-time flowmetry after termination of cardiopulmonary bypass, and we report five cases of early graft failure detected by the flowmeter. Electrocardiographic (ECG) changes were seen in only one of these five cases, and none of the patients had low cardiac output or other signs of graft failure at the end of the operation. The cause of graft failure was tagging in one case, rotation of internal mammary artery grafts in two and kinking of vein grafts in two cases. All errors were corrected, and control flowmetry showed normal flow rates after correction. Flowmetry takes less than 10 min, even with multiple bypass grafts. Based on our results, we advocate routine quality control with flowmetry after termination of cardiopulmonary bypass, since ECG changes are insufficient as checks of flow in bypass grafts.

Recurrent endocarditis in silver-coated heart valve prosthesis.

BACKGROUND AND AIM OF THE STUDY: In order to prevent prosthetic valve endocarditis (PVE), the implantation of a new silver-coated sewing ring has been introduced to provide peri- and postoperative protection against microbial infection. METHODS: A 56-year-old woman with aortic stenosis had elective replacement with a St. Jude Medical mechanical valve fitted with a silver-coated sewing ring (Silzone). The patient developed early PVE, which necessitated reoperation after one month. Despite a second Silzone prosthesis being implanted, the endocarditis recurred. During a third operation an aortic homograft was implanted, and after six months a fourth operation was performed for a pseudoaneurysm at the base of the homograft, in proximity to the anterior mitral valve leaflet. RESULTS: The diagnosis of PVE was confirmed by the presence of continuous fever, transesophageal echocardiography and growth of penicillin-resistant Staphylococcus epidermidis from the valve prosthesis. CONCLUSION: The implantation of all prosthetic valves is encumbered with a risk of endocarditis. Although silver has bacteriostatic actions, the advantages of silver-coated prostheses in the treatment of this condition have yet to be assessed in clinical trials.

Development of a model for measurement of adhesion strength of fibrin sealant to human tissue.

It is crucial for the surgeon to know the physical properties of a surgical sealant. Current test methods of fibrin sealant involving animal testing or in vitro testing of sealant using artificial substrates have little clinical relevance. Most of these test methods also lack accuracy and reproducibility. A new model was developed for testing strength and in vitro adhesion of fibrin sealant to vital human tissue using fresh vein leftover from coronary artery bypass grafting. The vein leftover was cut into samples and fastened in a tensiometer linked to a computer. Patient-derived fibrin sealant (0.1 ml) was applied to the tissue, and the surfaces of the tissue samples were held together for 5 min, and then automatically pulled apart by the tensiometer. Data were generated in a load cell and recorded and analysed by the computer. The reproducibility for the adhesion strength was 6.6%, adhesion energy 9.8%, and elongation at break 8.4%. The method has been considered ethical and has good reproducibility. The method can be used for standardised measurements and comparison of different types of fibrin sealant without the sacrifice of animals.

[Coronary bypass surgery using the radial artery. An alternative in patients with varicose veins]. / Koronar bypass-operation med a. radialis. Et alternativ hos patienter med varicer.

Arterial revascularization of the heart with the radial artery was performed in twenty patients with varicosities of the lower legs. The patients all had a good functional result and were free of angina pectoris after the operation. None of the patients had complications from harvest of the radial artery. The patients were mobilized early, as no veins had been harvested from the legs.

[Cardiac revascularization using both mammary arteries]. / Revaskularisering af hjertet med begge aa. mammariae.

Both internal mammary arteries in combination with veins were used for revascularization of the hearth in fifty Danish patients undergoing coronary artery bypass grafting (CABG) at Gentofte Hospital during the period 1994-1996. Patients with insulin-dependent diabetes mellitus, obesity, and age over 75 years were excluded. The patients were followed for at least one month after the operation. No patients died, and the complication rate was low and comparable to standard CABG using the left mammary artery and vein grafts. It is known from the literature that 10 years after CABG only 50% of vein grafts remain patent, and half of these have severe atherosclerosis. The mammary artery is far more resistant to atherosclerosis and 15 years after the procedure fewer patients have recurrent angina when both mammary arteries have been used. Bilateral mammary artery grafts can be used in half of CABG-procedures, and are especially indicated in younger patients.

Vivostat system autologous fibrin sealant: preliminary study in elective coronary bypass grafting.

BACKGROUND: The Vivostat System is a medical device for the preparation of an autologous fibrin sealant from 120 mL of the patient's blood in the operating room. The system is fully automated and microprocessor controlled and is made up of three components: an automated processor unit, an automated applicator unit, and a disposable, single-patient-use unit, which includes a preparation set and a Spraypen applicator. The biochemical process is initiated by batroxobin, which acts upon the fibrinogen in the patient's plasma. The completion of the process depends entirely on endogenous thrombin in producing the sealant. METHODS: Twenty-four volunteer patients undergoing elective primary coronary artery bypass grafting were randomized to either conventional hemostasis (control group) or the use of Vivostat fibrin sealant as an adjunct to conventional hemostasis. The patients were followed up at 1 month and 1 year. RESULTS: The preparation process was completed in 30 minutes. No safety issues associated with the use of the sealant were identified. From 120 mL of the patient's blood the yield of fibrin sealant was 4.5 mL (range, 3.9 to 4.8 mL). There was a favorable trend toward lower amounts of chest tube drainage in the Vivostat group. In the Vivostat group, 1 of 11 patients (9%) required a perioperative transfusion and in the control group 3 of 12 patients (25%) required a perioperative transfusion. CONCLUSIONS: It is possible to prepare autologous fibrin sealant with the Vivostat system in 30 minutes. No exogenous thrombin is required. The sealant has no known adverse effects and may prove to be a useful adjunct to hemostasis in cardiothoracic surgery.

Surgery of complex coronary arteriovenous fistula.

A rare type of coronary arteriovenous fistula with multiple supplying vessels from both coronary arteries and draining into the pulmonary artery was found in a 52-year-old woman with angina pectoris. The fistula was successfully closed by division of the vessels draining into the pulmonary artery.

Controlled clinical studies of fibrin sealant in cardiothoracic surgery--a review.

OBJECTIVE: More than 2300 clinical papers have been published on the surgical applications of fibrin sealant (FS), with the largest number in the speciality of cardiothoracic surgery. The purpose of this review of the literature was to find and evaluate controlled studies published in the field of cardiothoracic surgery, to clarify the indications and emphasize the benefits of FS available to the practising surgeon. METHODS: A database of the surgical publications of FS was created. Up to the end of 1995, at least 24 controlled clinical studies had been published; these may be divided into 20 studies with a positive outcome and 4 studies where the results were not different from the controls. In none of the studies was the clinical result worse after the use of FS. RESULTS: In most of the cardiac studies, FS was successfully used at bleeding sites in reoperations and in congenital heart surgery. Postoperative bleeding may also be reduced by the anterior mediastinal spray application of FS or by preparing woven Dacron prostheses with the sealant. In addition, Fs has been found to improve results after type A aortic disections and, by adding an antibiotic to the sealant, the postoperative infection rate for active endocarditis of the aortic root can be reduced. In pulmonary surgery FS can be used to reduce pulmonary air leakage, however the results of some studies diverge due to different clinical test conditions and the inclusion of only a small number of patients in the "negative" studies. In none of the controlled studies of esophageal surgery could FS prevent leakage from esophageal anastomoses. CONCLUSIONS: Fibrin sealant is safe when it is applied properly, but there is a learning curve for surgeons who start using it. An autologous sealant or a sealant containing human instead of bovine thrombin is preferred, since repeated use of bovine thrombin may induce coagulopthies. The number of controlled clinical studies of FS is currently increasing, with the majority of the papers revealing a beneficial effect of FS when it is used as a hemostatic or sealing agent in cardiothoracic surgery.

Repair of experimental atrial rupture with fibrin glue.

Ten cases of experimental atrial rupture were created in five pigs by cutting into both atria. The defects measured approximately 3.0 x 1.0 cm. Bleeding was stopped by applying a tangential clamp and the defect in the atrium was sealed with fibrin glue (mean volume 2.0 ml, range 1.5-2.5 ml) with a mean fibrin concentration of 23 mg/ml. The mean pressures in the atria were 11 cmH2O in the left and 10 cmH2O in the right atrium. The clamp was released after 5 min and the atria were observed for bleeding for 30 min. In four animals, immediate haemostasis was obtained. In one animal, both atria leaked after release of the clamp because too little fibrin glue was applied, but complete haemostasis was obtained at a second attempt. All experimental atrial defects could be sealed with fibrin glue (P = 0.03), and we believe, based on our experimental results, that fibrin glue may have a place in emergency cases to improve the management of atrial injury. In conclusion successful repair of experimental atrial rupture was performed by the use of fibrin glue.

Autologous fibrin glue for sealing vascular prostheses of high porosity.

Thirty high-porosity double-Velour vascular prostheses were sealed with fibrin glue, the fibrinogen in the glue being prepared from citrated plasma by ethanol precipitation. After such preparation the prostheses were blood-tight at a pressure > 300 mmHg. Using a fibrin concentration of 13 mg/ml (obtained by dilution of the fibrinogen solution) the prostheses were blood-tight at a minimum pressure of 150 mmHg, which is suitable for clinical use. Sufficient fibrin glue can be prepared from 44-88 ml of the patient's blood to seal most types of high-porosity vascular prosthesis used clinically. The fibrin-sealed grafts have good handling characteristics because they are soft, pliable and non-sticky. The use of autologous fibrin glue has obvious safety advantages by preventing both transmission of viral diseases and immunological reactions.

Important factors influencing the strength of autologous fibrin glue; the fibrin concentration and reaction time--comparison of strength with commercial fibrin glue.

Fibrin glue was prepared from citrated plasma of human donors by means of ethanol. The outcome was a fibrinogen concentrate with a mean concentration of 43 mg/ml. The fibrinogen was converted to fibrin by the addition of 0.3 part of thrombin solution, 150 NIH U/ml, containing 100 mM calcium chloride. In a rat model full-thickness skin grafts were sealed with the glue, and the adhesive strength was measured at different fibrin concentrations, and after a variable reaction time, and compared to commercial fibrin glue (Tisseel). The strength of ethanol-prepared glue was directly proportional to the fibrin concentration, and increased rapidly within the first minutes of the reaction time. The strength of the commercial glue could be obtained with autologous fibrin glue at the same fibrin concentration.

Preparation of autologous fibrin glue from pericardial blood.

To salvage patients' blood and improve hemostasis in cardiac operations, autologous fibrin glue was prepared in a new way by means of ethanol from pericardial blood. The yield from 44 mL of blood was 2.1 +/- 0.7 mL (mean +/- standard deviation) of fibrinogen concentrate with a concentration of 25.1 +/- 7.5 mg/mL; 2.7 mL of two-component glue was obtained after the addition of thrombin solution. The glue has the advantages of safety from transmission of viral diseases and from immunologic reactions.

[Pneumomediastinum]. / Pneumomediastinum.

Pneumomediastinum is a rare pathological condition with air in the mediastinum outside the trachea and oesophagus. The etiology may be spontaneous/resulting from exertion, traumatic, iatrogenic or it may be due to inflammation, neoplasm or perforation of a hollow abdominal organ. In pneumomediastinum resulting from exertion, a pressure gradient occurs and this causes rupture of marginally situated pulmonary alveoli. Air escapes from the alveoli into the perivascular adventitia and dissects its way along the vessels to the mediastinum. The commonest symptoms are pain in the thorax in 80-90% of the patients, followed by sensation of oppression and dysphagia. Stethoscopic examination reveals crepitation synchronous with pulse and respiration in half of the cases. The diagnosis is verified by radiographic examination of the thorax where air can be seen as vertical radio-translucent regions in the mediastinum and along the borders of the heart. Patients with pneumomediastinum should be admitted to hospital for investigation as treatment of a possible basic condition, e.g. rupture of the oesophagus or bronchus, is important. In uncomplicated cases, the mediastinal emphysema disappears in the course of a week. Mediastinotomy with incisions for relief of pressure may prove necessary.

A simple method of preparation of autologous fibrin glue by means of ethanol.

We describe herein a new system for the preparation of autologous fibrin glue by means of ethanol. The system produces a good yield of fibrin glue with a high concentration of fibrinogen in a short period of time, making the glue an efficient hemostatic agent and surgical sealant, and autologous fibrin glue has the obvious advantages of safety from transmission of viral agents and from immunologic reactions.