Vijay V. Kakkar

NATURAL HISTORY OF POSTOPERATIVE DEEP-VEIN THROMBOSIS

Abstract 132 consecutive patients were investigated during the postoperative period using the 125 I-labelled fibrinogen test to detect deep-vein thrombosis in the legs. Thrombosis developed in 40 patients (30%) and was confirmed by phlebography. In 14 of these patients the thrombus lysed spontaneously within seventy-two hours. Thrombosis persisted for more than seventy-two hours in 26 patients and pulmonary embolism developed in 4 of them. The radioactive fibrinogen test can be used in a large number of patients to detect venous thrombosis at an early stage. It indicates which patients are at risk and which require active treatment.

Impaired myocardial angiogenesis and ischemic cardiomyopathy in mice lacking the vascular endothelial growth factor isoforms VEGF164 and VEGF188.

Impaired myocardial angiogenesis and ischemic cardiomyopathy in mice lacking the vascular endothelial growth factor isoforms VEGF 164 and VEGF 188

Deep vein thrombosis of the leg: Is there a “high risk” group?

Summary Two hundred and three patients undergoing elective surgery were investigated to determine the group of patients who are at a “great risk” of developing deep vein thrombosis. It was found that the patients who formed this group included those who had a history of previous deep vein thrombosis or pulmonary embolism, those who had varicose veins or underwent operation for malignant disease, and elderly patients (over sixty-one years) having major operations. All of these patients are at a “great risk” of developing thrombosis during the postoperative period.

Lipid peroxides and atherosclerosis

Plasma lipid peroxide concentrations were measured in 100 patients with occlusive arterial disease proved angiographically (50 patients with ischaemic heart disease, 50 with peripheral arterial disease) and compared with values in 75 control patients with no clinical evidence of atherosclerosis. Lipid peroxide concentrations were significantly higher in patients both with ischaemic heart disease (median 4.37 mumol/l (interquartile range 3.85-5.75 mumol/l); p less than 0.001) and with peripheral arterial disease (median 4.37 mumol/l (3.88-5.21 mumol/l); p less than 0.001) than in controls (median 3.65 mumol/l (interquartile range 3.29-3.89 mumol/l). Overall there was a significant but weak correlation between plasma lipid peroxide and plasma triglyceride concentrations (rs = 0.25; p less than 0.001) but not between plasma lipid peroxide and plasma total cholesterol concentrations. Furthermore, hypertension, obesity, diabetes, smoking, positive family history, and intake of beta blockers and thiazide diuretics were not associated with significant differences in lipid peroxide values. This study provides clinical support to experimental data indicating that peroxidised lipids may be important in atherogenesis and its complications and also suggests that peroxidised lipids may provide an index of the severity of atherosclerosis.

Prevention of venous thrombosis and pulmonary embolism

Deep vein thrombosis (DVT) leads to hospitalization for up to 600,000 persons each year in the United States. Venous thrombosis in itself may be benign, but the condition can lead to dangerous complications and has a high recurrence rate. Strategies to prevent DVT involve prevention of stasis and reversal of changes in blood coagulability that allow thrombi to form. Pharmacologic agents have been effective in reducing the incidence of DVT and pulmonary embolism. Low-dose subcutaneous heparin is considered a nearly ideal DVT preventative for surgically treated patients. The risk of hemorrhage is the main limitation to routine use of subcutaneous anticoagulants for DVT, but careful patient selection can minimize that risk. After anticoagulant therapy with heparin, generally for 7 to 10 days, oral warfarin is the drug of choice for maintenance anticoagulation to prevent DVT recurrence. Therapy for pulmonary embolism is the same as for DVT--immediate anticoagulation with heparin followed by maintenance with warfarin.

Low molecular weight versus standard heparin for prevention of venous thromboembolism after major abdominal surgery

Abstract Low-molecular-weight heparin (LMWH) is effective in the prevention of postoperative venous thromboembolism but does it have the safety advantages over standard heparin (SH) that have been claimed? In a multicentre randomised trial in 3809 patients undergoing major abdominal surgery (1894 LMWH, 1915 SH) heparin was given preoperatively and continued for at least 5 postoperative days. Patients were assessed in the postoperative period and were followed up for at least 4 weeks, the emphasis being on safety. Major bleeding events occurred in 69 (3·6%) patients in the LMWH group and 91 (4·8%) patients in the SH group (relative risk 0·77, 95% confidence interval 0·56-1·04; p=0·10). 93 indices of major bleeding were observed in the 69 LMWH patients and 141 in the SH patients. (p=0·058). Severe bleeding was less frequent in the LMWH group (1 0% vs 1·9%; p=0·02), as was wound haematoma (1·4% vs 2·7%; p=0·007). Bleeding episodes with LMWH were less likely to lead to further surgery to evacuate a haematoma or to control bleeding, and injection site bruising was also less common in the LMWH group. No significant differences were found in the efficacy of the two agents. Perioperative death rates were 3·3% in the LMWH group and 2·5% in the SH group; pulmonary emboli were detected in 0·7% and 0·7%; and deep-vein thrombosis was diagnosed in 0·6% of patients in each group. Follow-up was done on 91% of 3699 evaluable patients. There were 19 further deaths (10 LMWH, 9 SH group) and 25 patients with thromboembolic complications (15 and 10). Of the 3 patients with fatal pulmonary emboli during follow-up 2 had received LMWH and 1 SH. The two drugs were of similar efficacy. The primary end point, the frequency of major bleeding, showed a 23% reduction in the LMWH group, but this difference was not significant. The secondary safety end points revealed that LMWH was significantly better than SH. Fatal pulmonary embolism occurs rarely (0·09%) following discharge from hospital so the cost benefit ratio would not justify prolonged prophylaxis in this setting.

The origin of deep vein thrombosis: a venographic study

Abstract A venographic technique has been described which demonstrates the soleal veins in addition to the rest of the deep veins of the lower limb consistently in the presence or absence of thrombosis. In 127 consecutive patients, the soleal veins were demonstrated in all but three. In 97 surgical and medical patients with clinically suspected deep vein thrombosis, the presence of thrombi was confirmed by venography only in 51 (52 per cent); the remainder had normal deep veins. In nine patients the soleal veins were the only site of thrombosis. Only one patient was found with thrombosis proximally and normal soleal veins. In the remaining patients whenever there were thrombi proximally they were also present in the soleal and intervening veins. It is concluded that in the majority of patients thrombi start in the soleal veins in the calf. It has also been shown that the clinical diagnosis of deep vein thrombosis is unreliable and no patient should be given anticoagulant therapy without first confirming t...

PREVENTION OF FATAL POSTOPERATIVE PULMONARY EMBOLISM BY LOW-DOSE HEPARIN

The efficacy of low-dose heparin to prevent fatal postoperative pulmonary embolism was investigated in this multicentered trial. The original data from 28 trial centers were published in 1975 but inadequacies in data from 1 center led to recomputation of these data excluding the 1 questionable centers results. Of 4031 patients remaining after exclusion of these data 2033 were in the control group and 1998 in the heparin-treated groups. 4.2% (n=170) died postoperatively overall: 94 among controls and 76 in the heparin group. Autopsies were performed on 70.2% of controls and 65.7% of heparin patients. 21% (n=15) of controls autopsied died due to actue massive fatal pulmonary embolism whereas none of the heparin-treated subjects died from postoperative pulmonary embolism. (P < .001). Data exclusion did not significantly alter the total incidence of deep-vein thrombosis nor of bleeding complications observed in both groups postoperatively.

Femoral vein thrombosis and total hip replacement.

Of 160 patients who underwent total hip replacement, 81 developed venographic evidence of thrombi in the operated leg. In 46 cases (57%) the thrombus originated from the femoral vein, and in 43 of these the exact site of origin was defined by venography. In 34 cases (74%) the thrombus arose from the wall of the femoral vein at the level of the lesser trochanter. This region was studied by intraoperative venography in eight patients undergoing total hip replacement, and in every case severe distortion of the common femoral vein was observed, producing almost total occlusion. We suggest that intraoperative damage to the femoral vein results from manipulation of the leg, and that this is one reason why the operation is followed by a high incidence of deep vein thrombosis in the upper femoral region.

LOW DOSES OF HEPARIN IN PREVENTION OF DEEP-VEIN THROMBOSIS

Abstract 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.