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Background It is controversial issue that heparin decreases thrombosis for microsurgical anastomosis, and its effective role is under discussion. This study is for proving whether low-dose heparin is preventing thrombosis in free flap reconstruction. Methods Through chart reviews of 134 patients, using low-dose heparin for free tissue transfer from 2011 to 2016, retrospective analysis was performed. 33 patients received low-dose heparin therapy after surgery. And 101 patients received no-heparin therapy. Complications included flap necrosis, hematoma formation, dehiscence and infection. Results In no-heparin therapy group, comparing the flap necrosis revealed 16 cases (15.84%). And, flap necrosis was 6 cases (18.18%) in low-dose heparin therapy group. The statistical analysis of flap necrosis rate showed no significant difference (p=0.75). The results showed that there was no significant difference of flap necrosis rate between two groups. Conclusion In this study, patients in the low-dose heparin group had no significantly lower rates of flap failure compared with no-heparin group. This suggests that low-dose heparin may not prevent thrombosis and subsequent flap failure to a significant extent.

Purpose Pipeline embolization devices (PEDs) are associated with inherent thrombotic complications as well as potentially catastrophic spontaneous intraparenchymal hemorrhage. Anti-platelet and anticoagulation therapy must be optimized to reduce thrombotic complications without increasing the incidence of hemorrhage. Post-procedural low dose heparin drip is a prophylactic measure to reduce ischemic stroke risk, with no published data to date reporting efficacy and complications. Here we report the thrombotic and hemorrhagic complication rates of patients receiving post-operative low dose heparin drip, and we compare our results to the published literature rates of patients not receiving such prophylaxis. Materials and methods We completed a retrospective review of patients who had intracranial aneurysms treated with the Pipeline Embolization Device at Westchester Medical Center. A total of 73 individuals received post-operative low dose heparin for an average of 18 hours. Thrombotic and hemorrhagic complications were identified and reported. These rates were compared to the published literature rates of individuals not receiving post-operative heparin. Additional variables included PTT range, type of heparin protocol used (weight based vs physician controlled), total time of heparinization, heparin dose, and number of PEDs deployed. Results 0% (0/73) patients developed thrombotic complications in the post-operative period. The reported literature rate of symptomatic thrombotic events is 6.6%. Post-operative heparin reduced symptomatic thrombotic complications following PED placement (p=0.0125). 2.7% (2/73) patients developed intraparenchymal hemorrhage resulting in neurological deficit, compared to a published rate of hemorrhagic complications approximating 3%. Conclusions Post-procedural low dose heparin prophylaxis reduces thrombotic complications in the post-operative period, without increasing hemorrhagic complications. Disclosures I. Rybkin: None. J. Cooper: None. G. Kaur: None. F. Al-Mufti: None. C. Gandhi: None. J. Santarelli: None.

Objectives: To identify patient, hospital, and central venous catheter factors that may influence the use of low-dose heparin infusion for central venous catheter patency in critically ill children. Design: Secondary analysis of an international multicenter observational study. Setting: Fifty-nine PICUs over four study dates in 2012, involving seven countries. Patients: Children less than 18 years old with a central venous catheter who were admitted to a participating unit and enrolled in the completed Prophylaxis against Thrombosis Practice study were included. All overflow patients were excluded. Interventions: None. Measurements and Main Results: Of the 2,484 patients in the Prophylaxis against Thrombosis Practice study, 1,312 patients had a central venous catheter. Five hundred seven of those patients used low-dose heparin infusion. The frequency of low-dose heparin infusion was compared across various patient, hospital, and central venous catheter factors using chi-square, Mann-Whitney U, and Fisher exact tests. In the multivariate analysis, age was not a significant factor for low-dose heparin infusion use. Patients with pulmonary hypertension had decreased low-dose heparin infusion use, whereas those with active surgical or trauma diagnoses had increased low-dose heparin infusion use. All centrally inserted central venous catheters were more likely to use low-dose heparin infusion when compared with peripherally inserted central venous catheters. The Asia-Pacific region showed increased low-dose heparin infusion use, along with community hospitals and smaller ICUs ( Conclusions: Patient, central venous catheter, and hospital factors are associated with the use of low-dose heparin infusion in critically ill children. Further study is needed to evaluate the efficacy and persistence of low-dose heparin infusion use.

Background: Transradial access (TRA), compared to femoral access, is preferred for coronary procedures due to reduced access-related bleeding and mortality. Radial artery occlusion (RAO) is a known complication of TRA, and precludes its use as a future access site, conduit for CABG or for

This study reports our preliminary experience of percutaneous coronary angioplasty with low dose heparin and immediate withdrawal of the femoral sheath. After selection, 120 patients underwent a procedure with a low dose of heparin (4,300 ± 700 IU). A total of 120 of 123 lesions (97.6%) were treated successfully by the femoral route. There were no major cardiac complications during the procedure and hospital stay. Patients were allowed to be ambulant 6 hours after the procedure. No significant bleeding occurred. There was no need for surgery relative to the approach route nor for blood transfusion. The use of low dose heparin and immediate withdrawal of the femoral sheath did not increase the risk of coronary angioplasty in these selected patients. The period of bed confinement was shortened and the patients were ambulant earlier, leading to a reduction in their hospital stay with no increase in costs.

We retrospectively studied the incidence of recurrent embolization and hemorrhagic complications during a 2-week period after the onset of cardioembolic stroke according to the form of anticoagulation

Background At many centers, various heparin doses have been administrated systemically during living donor partial hepatectomy in an effort to minimize the potential for graft vascular thrombosis, which could lead to delayed graft function. However, there is no consensus regarding the advisability of heparin administration during living donor hepatectomy for liver transplantation. Methods We prospectively enrolled 270 donors between 2005 and 2011 to investigate donor and recipient outcomes between a low dose (25 IU/kg) and a conventional dose of heparin (50 IU/kg). Results The low-dose heparin group did not show an increased incidence of vascular thrombosis: the rates of hepatic artery and portal vein thromboses were not significantly different between the two groups ( P = .935 and P = .158, respectively). In addition, injection of low-dose heparin reduced donor complications with significant differences in postoperative hospital stay ( P P P = .05/ P = .02) and hemorrhagic complications ( P = .004). Conclusions Administration of low-dose heparin during living donor hepatectomy can be used without worsening vascular thrombosis or donor complications.

The effect was studied of adding heparin to 10 per cent dextrose and to total parenteral nutrition (TPN) solutions infused into peripheral veins of premature babies. The median survival times of sites receiving 10 per cent dextrose and TPN solutions without heparin were 37 and 22 hours, respectively. Addition of 0. liu/ml heparin had little effect whereas adding 0.25iu/ml increased survival times to 48 and 32 hours, respectively. Adding 0.5iu/ml heparin increased survival times to 67 and 68 hours, and with liu/ml they rose further still, to 69 and 83 hours, respectively. These data suggest that 0.5iu/ml may be sufficient to prolong the survival of peripheral intravenous sites in premature babies.

This review examines the role of graduated elastic compression stockings in the prevention of postoperative deep vein thrombosis. Used alone compression stockings reduce the incidence of postoperative deep vein thrombosis by approximately 60 per cent and when used in combination with other preventive methods, such as low dose heparin or intermittent calf compression, they further reduce the incidence by up to 85 per cent.

The safety and feasibility of early ambulation was evaluated prospectively in 907 patients undergoing elective coronary angioplasty and stenting with the use of 6Fr guiding catheters, low-dose heparin (5,000 IU), and immediate postprocedural sheath removal by comparing ambulation after 4 hours with immobilization for at least 12 hours. Because no excess in puncture site complications (2.3% vs 2.2%) could be demonstrated after 4-hour ambulation, it is concluded that early ambulation after 6Fr guiding catheter angioplasty by the femoral route with low-dose heparin is feasible, safe, and may facilitate a shorter hospital stay.

Prophylaxis with standard low dose subcutaneous heparin has been shown to significantly decrease the risk of deep vein thrombosis and pulmonary embolism, without major bleeding complications. The present report describes a case of unexpected hematoma formation, possibly secondary to subcutaneous low dose heparin injection that was administered in the anterior abdominal wall in a patient who had previously undergone a transverse rectus abdominis musculocutaneous flap reconstruction.

In their article on low-dose heparin thromboembolism prophylaxis, Owings and Blaisdell 1 cited decreased levels of antithrombin III in severely injured patients as a reason for the failure of therapy with low-dose heparin. If this hypothesis holds true, then increasing the dose of unfractionated heparin, which would counteract the reduced bioavailability, or administering a product with predictable bioavailability such as low-molecular-weight heparin (LMWH) should be equally efficacious. The authors mention that the primary problem with the use of LMWH is the inability to document the effect of a given dose except through measurement of ex vivo antifactor Xa activity. Clinical evidence is mounting that LMWH is an option for thromboembolism prophylaxis in high-risk patients without routine laboratory study monitoring. 2 The antifactor IIa and Xa response differs with LMWH preparations. Therefore, these preparations should be evaluated individually for clinical efficacy. The conclusions drawn in this literature review are not consistent

In a prospective randomised trial patients receiving multiple-day chemotherapy and heparin had significantly fewer local complications at the site of venous access than patients who had chemotherapy alone. The need to move peripheral venous catheters to other sites was decreased significantly, from 36% to 6%. Prophylaxis of phlebitis with low-dose continuous heparin is safe, simple, cheap and effective. It facilitates administration of multiple-day chemotherapy for the patients, the nurses and the physicians.

We appreciate the comments of Drs Hughes and Gonzalez. However, it seems that they have misunderstood the mechanism of action of LMWH and made an incorrect conclusion in their letter. Increasing the dose of heparin compensates for the reduced bioavailability of antithrombin III, not the reduced bioavailability of heparin. Therefore, even though LMWH have a more predictable bioavailability than unfractionated heparin, the anticoagulant effect of the LMWH is dependent on the bioavailability of antithrombin III. In fact, because LMWH have a greater concentration of the pentasaccharide chain responsible for antithrombin III activation and fewer high-molecular-weight fractions (responsible for the minor direct heparin antithrombotic effect), they are even more critically dependent on the presence of antithrombin III for their effect. To state this another way, if there is inadequate antithrombin III, both unfractionated heparin and LMWH are ineffective. We understand that different LMWH preparations have different ratios of anti-IIa

Objective: To determine a rational approach to heparin dosing for thromboembolism prophylaxis. Design: Literature review. Results: Three commonly used heparin dosing regimens were identified: (1) standard low-dose heparin (5000 U administered subcutaneously 2-3 times per day); (2) adjusted-dose heparin (adequate to elevate the activated partial thromboplastin time to 5 seconds above the upper limit of normal); and (3) low-molecular-weight heparin (30 mg subcutaneously twice daily without monitoring). Conclusions: Adjusted-dose heparin thromboembolism prophylaxis is both the safest and most reliable method currently available. Arch Surg. 1996;131:1069-1073

A total of 4352 patients were admitted to a prospective' randomised multicentre trial comparing the prophylactic efficacy of dextran 70 and low-dose heparin against fatal pulmonary embolism after elective operations for general, orthopaedic, urological, and gynaecological conditions. Out of 3984 patients correctly admitted, 1993 were allocated to receive dextran 70 and 1991 to receive low-dose heparin. Withdrawal of prophylaxis because of bleeding or technical difficulties occurred more often in the heparin group, but allergic reactions were more common in the dextran group. Of the 75 patients who died within 30 days after operation, 38 had been given dextran and 37 low-dose heparin. Necropsy was performed in 33 and 32 of these cases respectively. In six patients in each group pulmonary embolism was the sole or a contributory cause of death. Of these, five patients in the dextran group and two in the heparin group had received a full course of prophylaxis. There was no statistically significant difference between the two treatment groups in the incidence of fatal pulmonary embolism after a full course of prophylaxis.

56 patients undergoing elective major surgery received low dose heparin prophylaxis, 5,000 IU 2 h before surgery and every 8 h for 7 days. The patients were tested by the 125I-fibrinogen uptake test, which, if positive, was controlled by venography. The heparin concentrations were measured by the method of Denson and Bonnar and by the chromogenic method of Teien et al. in blood samples drained immediately before and after surgery and on the 1st and 5th postoperative day 2 and 4 h after the injection of heparin. The values were found higher when estimated by the method of Denson and Bonnar than by the chromogenic method. Deep vein thrombosis (DVT) developed in 11 patients, and in 10 of them within the first 48 after the operative procedure, in 1 after 4 days. The preoperative values were not lower in the patients who developed DVT, and the heparin concentrations found on the 1st and 5th postoperative day were at the same level as in those who did not develop DVT.

An ischemic bowel model was used to stimulate adhesion formation in eight ponies. Heparin (40 USP u/kg) or saline was administered intravenously at surgery and was continued subcutaneously every 12 hours for 48 hours to evaluate the efficacy of heparin in preventing intraabdominal adhesions. Ponies were euthanatized after 6 weeks, and postmortem examinations were performed. A statistically significant difference was found between the heparin-treated and the control groups. Adhesions developed in three of four control ponies, and adhesions did not develop in three of four heparin-treated ponies. None of the adhesions resulted in clinical disease. In this study, heparin decreased the formation of adhesions in ponies after experimentally induced intestinal ischemia.

The aim of this investigation was to study the beneficial role of low-dose heparin in peritonitis. Peritonitis was induced in 20 dogs by the technique of Rosato and co-authors, 10 of which received low-dose heparin subcutaneously for 5 days in a dose of 100 units/kg body weight. Decreased mortality as well as decrease in the formation of intra-abdominal abscesses and adhesions were observed in the heparin-treated dogs. Some of the possible underlying mechanisms for beneficial effects of heparin in peritonitis are discussed.

SummaryThe efficacy of topical thrombin in prevention of wound haematoma inpatients receiving subcutaneous low-dose heparin was studied in a randomized, controlled trial. One hundred and two patients undergoing elective abdominal surgery were included in the trial. Haematological studies were carried out in the last 42 patients to determine whether introduction of thrombin into the wound resulted in any systemic effect via the coagulation pathways. The frequency of post-operative wound haematoma was significantly lower in the thrombin-treated group as compared to the control group and its action appeared to be independent of any change in coagulation parameters.

• Carotid artery ligation, whether elective or an emergency, is an operation that most head and neck surgeons do with some trepidation because of the possible neurologic consequences. Of 440 major head and neck operations for cancer in which the carotid artery was exposed, 20 (4.5%) patients suffered a carotid rupture or had the vessel ligated just prior to rupture. We describe the typical patient and his management. Of these 20 patients, five died as a direct result of rupture or ligation, ten survived rupture and/or ligation with neurologic sequelae, and five survived rupture and/or ligation without neurologic sequelae. Of the ten patients with neurologic problems, four had immediate strokes, and six had delayed strokes, ie, these occurred greater than eight hours after ligation. Seven patients who required carotid artery ligation, separate from the previously mentioned group, received 5,000 units of heparin sodium subcutaneously every 12 hours in a prospective study. Of these seven patients, one died immediately postoperatively, and six survived without any neurologic sequelae. We discuss the cause of delayed neurologic problems and the rationale for the use of low-dose heparin. (Arch Otolaryngol104:307-310, 1978)

We investigated whether the dosage of heparin injected subcutaneously for the postoperative prophylaxis of thromboembolism influences efficacy. We considered prospective, controlled or comparative, randomized studies in which heparin was administered in a dosage of 5,000 U b.i.d. or t.i.d. subcutaneously. In major surgical procedures in general surgery, gynecology, urology and chest surgery, 2 × 5,000 and 3 × 5,000 U of heparin/day lower the frequency of postoperative deep venous thrombosis from about 30% to about one-fourth and one-third that amount, respectively. With regard to orthopedic/ traumatic surgery, in a study of only 40 patients, 2 × 5,000 U/day reduced the incidence of thrombosis by one-half. The use of the higher dosage resulted in a decrease in DVT in 5 of 7 reports, but the other two authors measured no prophylactic effect at all. Proof that subcutaneous heparin prophylaxis is also able to reduce the number of fatal postoperative pulmonary emboli has been produced only in the case of the higher dosage. In our own group of patients there is no correlation between body weight and frequency of hemorrhagic complications. In our patients there is no relation between malignant tumor as the primary disease and the occurrence of hemorrhagic complications. There is no evidence that the lower dosage causes fewer hemorrhagic complications than the higher dosage.

The effect of heparin, 5000 units every 8 hours, on deep venous thrombosis in patients with proximal femoral fractures was investigated in a controlled, double blind, randomised study. Heparin or placebo was administered as soon as possible after the fracture, and before 6 hours had passed, and was continued for 14 days. The diagnosis of deep venous thrombosis was made using daily I125 fibrinogen scans. A total of 130 patients endured the trial and the results were registered on a sequential diagram. This showed that the 0-hypothesis could not be rejected, and that consequently no difference in the frequency of deep-vein thrombosis was detected.

Since 1973 a prospective trial of antithrombotic agents for the prophylaxis of deep venous thrombosis and pulmonary embolism was undertaken in 386 high risk patients. Five drugs were employed: 1. A combination of aspirin and dipyridamol (95 patients); 2. Dextran 60 (43 patients); 3. Dihydroergotamine (61 patients); 4. Low dose heparin (63 patients); 5. A combination of dihydroergotamine and low dose heparin (twice daily in 61 patients and three times daily in 63 patients). The patients were investigated by I125 fibrinogen uptake test, phlebography, lung scan and careful clinical evaluation before and after operation. In cases of established thrombosis simultaneous anticoagulation with heparin and coumadin was started. In the first group, 32 (34%) thromboses and three pulmonary emboli were detected of which one patient died. In the dextran group, 24 patients (54%) developed thrombosis and there were no fatal pulmonary emboli. In the low dose heparin group we detected 29 (46%) thromboses and three pulmonary emboli. Only the combination of low dose heparin and dihydroergotamine significantly reduced the incidence of thromboembolic complications-15 (25%) thromboses and no pulmonary emboli. The application of this combination three times a day showed no further improvement but more haemorrhagic complications appeared. Since 1975 no fatal pulmonary emboli have occurred in 720 patients undergoing total hip replacement.

A prospective study of pulmonary embolism utilizing low dose heparin in 125 postoperative patients failed to demonstrate a significant reduction in deep venous thrombosis diagnosed by fibrinogen scanning. However, the incidence of probable pulmonary emboli diagnosed by pulmonary scanning in the absence of chronic lung disease appeared to be reduced by the low dose heparin regimen.

Increasing awareness of the dangers of low dose heparin therapy has stimulated interest in mechanical methods for decreasing the incidence of thromboembolism. Plantar flexion and dorsiflexion of the feet while the patient is on the operating table by the use of a mechanical device (the Pedi-Pulsor) significantly decreases the incidence of deep vein thrombosis (45 percent in control patients versus 18 percent with the Pedi-Pulsor [p = 0.05]). In addition, use of this machine during the postoperative period should further aid in decreasing the incidence of thromboembolism.

In 100 patients who underwent major cranial or spinal operations, the incidence of lower extremity deep vein thrombosis was 29%. Of importance was the presence of known risk factors, particularly leg weakness and a long operation. The subject of deep vein thrombosis and its complications in neurosurgical disorders is reviewed and its prophylaxis is discussed. The administration of low dose heparin based on an epidemiological analysis of the risks involved would seem to be an effective method of prophylaxis.

In a double blind study, three different methods of prophylaxis of thromboembolism were compared in surgical patients. Each group received either acetylsalicylic acid or low dose heparin or a combination of both drugs. The groups were comparable for type of surgery, sex, age, weight, and other risk factors. A significantly lower incidence of thromboembolism was found in the combined prophylaxis group than in the two other groups. The total rate of complications attributable to prophylaxis was low except for a mild but significantly increased bleeding tendency in the combined prophylaxis group. Hemorrhagic complications in most cases were slight side effects which permitted to continue prophylaxis.

The laboratory control of low-dose heparin therapy is generally regarded as unnecessary. A laboratory study of the effects of low-dose heparin was performed using different methods: an amidolytic method and a method involving the inhibition of factor Xa in a coagulation test. Variations in partial thromboplastin time, recalcification clotting time, thrombin time and the plasma antithrombin HI levels were also studied. These tests were repeated (days 0, 1, 3, 8) in 27 women between the ages of 27 and 62 years who were undergoiing gynecological surgery. They received 5,000 IU of heparin either twice or thrice daily. There was no correlation between heparin levels in the blood and global clotting tests simultaneously performed. The plasma heparin levels varied between 0 and 0.15 IU/ml with both methods. A detectable heparin concentration on days 1, 3 and 8 was present in only half of the cases receiving the twice daily regimen. The plasma antithrombin III activity and concentration were not modified during treatment.

The study was carried out on 75 patients undergoing hip joint surgery. The efficacy of a prophylaxis of deep vein thrombosis (DVT) by acetylsalicylic lysine (ASL) and by a low dose heparin (LDH) combined with the ASL treatment was investigated using the 125I-fibrinogen test. DVT was not significantly decreased by the ASL application (53%) compared to the controls (60%). DVT occurred significantly less under the combined administration (27 %) than in the other two groups.

In a randomised double-blind controlled trial 24 patients undergoing elective aortic bifurcation graft surgery received subcutaneous calcium heparin (2,500 u pre-operatively then 5,000 u 12-hourly for 7 days) and 25 control patients received saline injections. All patients received a routine dose of intravenous sodium heparin intra-operatively. The trial was terminated because of excess bleeding complications in patients receiving subcutaneous heparin (8 vs. 1, p less than 0.05). Deep vein thrombosis occurred in 6 control patients and 2 patients on heparin (p less than 0.05). In this group of patients undergoing major vascular surgery the risk of bleeding due to heparin outweighed the potential benefit of thrombotic prophylaxis.

SummaryThe object of the present investigation was to identify those who, among high-risk patients, would “break through” low-dose heparin prophylaxis and develop thromboembolism after major abdominal surgery.Twenty-nine variables (clinical characteristics, pre- and postoperative coagulation and fibrinolytic factors) from 19 patients with and 26 patients without thromboembolism were analyzed by means of a multivariate supervised pattern recognition technique (SIMCA).We found no statistically significant difference between patients with and without thromboembolism. Thus, in the studied group of high-risk patients it was not possible to identify a predictive index for selection of individual patients liable to develop postoperative thromboembolism despite low-dose heparin prophylaxis in major abdominal surgery.

Preventing hemorrhage in high-risk hemodialysis: Regional versus low-dose heparin. Hemodialysis in patients with increased risk for hemorrhage can be accomplished with either a regional or a low, total dose of heparin. In a prospective study of 69 series of dialyses performed on an alternating schedule of heparinization for each patient, bleeding complications during and immediately following dialysis occurred in 23 of 122 dialyses (19%) with regional heparin compared to 13 of 133 dialyses (10%) with low-dose heparin (P < 0.05). The incidence of hemorrhage correlated with the estimated degree of bleeding risk both at expected and at occult bleeding sites, and was the same or higher with regional heparin in all categories. Hemorrhage was not correlated with preexisting coagulation abnormalities, concurrent anticoagulant drugs, level of azotemia, or ability to successfully limit systemic heparinization during dialysis. The incidence of partial clotting of the dialyzer was 3 to 5% with both heparin protocols. We conclude that regional heparinization has no clinical or practical advantage over low-total-dose heparin in preventing bleeding associated with hemodialysis.Prévention de l'hémorragie au cours de l'hémodialyse à haut risque: Héparinisation régionale ou héparinisation à faibles doses. L'hémodialyse des malades dont le risque hémorragique est élevé peut être réalisée soit avec une héparinisation régionale soit avec une dose totale faible d'héparine. Au cours d'une étude prospective portant sur 69 séries de dialyses réalisées selon un protocole où les modes d'héparinisation étaient alternés chez chaque malade, les complications hémorragiques au cours et au décours immédiat de la dialyse ont été observées dans 23 dialyses sur 122 (19%) conduites avec une héparinisation régionale et 13 dialyses sur 133 (10%) réalisées avec une faible dose d'héparine (P < 0,05). La fréquence des hémorragies était corrélée avec l'évaluation du risque de saignement et elle a été la même ou plus grande lors de l'héparinisation régionale. L'hémorragie n'a pas été corrélée avec les anomalies pré-existantes de la coagulation, les traitements anticoagulants, l'importance de l'azotémie ou la possibilité de limiter efficacement l'héparinisation au cours de la dialyse. La fréquence de la coagulation partielle dans le dialyseur a été de 3 à 5% avec l'un et l'autre des protocoles. Nous concluons que G héparinisation régionale n'a d'advantage ni clinique, ni pratique sur l'utilisation d'une dose totale faible d'héparine dans la prévention du saignement associé à l'hémodialyse.

Heparin in low doses was given by subcutaneous injection to 25 patients with femoral neck fractures; a further 26 patients acted as a control group. Deep-vein thrombosis was diagnosed by the 125I-fibrinogen test. Thrombosis occurred in 68 per cent of patients in the heparin group and in 50 per cent of the controls. The incidence of deep-vein thrombosis was not increased when operative fixation of the fracture was delayed for more than 24 hours. It appears that the initial thrombosis may occur very soon after the fracture and as a direct response to the trauma, rather than to the operation itself.

Clinical trials have inherent limitations that frequently lead to wide disagreements among both statisticians and clinicians.1 In fact, continued criticisms of clinical trials have produced skeptic...

In a double-blind investigation thromboembolic prophylaxis with subcutaneous low-dose heparin was studied in 112 patients admitted for elective major surgery. Pulmonary embolism was diagnosed by photoscanning on the third or fourth day after operation, and plain chest X-rays were taken simultaneously. Deep vein thrombosis (D.V.T.) was detected by the 125 I-fibrinogen leg scanning technique. 58 patients were treated with heparin, each receiving 5000 units every 12 hours for 5 days, starting 2-5 hours before operation. In this group 11 patients (19%) had pulmonary embolism and/or D.V.T. Of the 54 patients in the control group 30 (56%) had pulmonary embolism and/or D.V.T. Thus low doses of heparin reduce the incidence of tromboembolism after major surgery.

The effectiveness of subcutaneous heparin in the prophylaxis of deep-vein thrombosis was investigated in 53 consecutive patients over the age of 50 undergoing repair of inguinal hernia. Deep-vein thrombosis was detected by means of the 125 I-fibrinogen test in 7 (26%) of the 27 control patients, while this was significantly reduced (4%) in the 26 similar patients who received heparin before and after surgery.

From the Narayana Hrudayalaya Institute of Medical Sciences, Bangalore, India; and theDepartment ofCardiology, St. John’sMedicalCollegeHospital,Bangalore, India. Disclosures: Authors have nothing to disclose with regard to commercial support. Received for publication Dec 13, 2011; revisions received March 2, 2012; accepted for publication March 16, 2012; available ahead of print April 27, 2012. Address for reprints: Naoto Morimoto, MD, PhD, Department of Cardiovascular Surgery, Himeji Cardiovascular Center, 520, Saishoko, Himeji, Hyogo, 670-0981, Japan (E-mail: naotofrcs@gmail.com). J Thorac Cardiovasc Surg 2012;144:726-8 0022-5223/$36.00 Copyright 2012 by The American Association for Thoracic Surgery http://dx.doi.org/10.1016/j.jtcvs.2012.03.030