A European view on the North American fifth consensus on antithrombotic therapy

An American-Canadian group of experts have, in the November 1998 issue of CHEST, published for the fifth time their recommendations for antithrombotic therapy. This remarkable consensus document was the result of an extensive review of the literature by an interdisciplinary group. Considering the impact of this document on medical practice, also outside North America, a group of European experts reviewed in detail the fifth report, particularly the sections on clinical indications of antithrombotic treatment. The aim was not to indicate the many areas of agreement and to quote literature that has become available since publication of the last consensus documents, but rather to refer to the gray zones of uncertainty and limited number of divergent opinions.

Outcome and one year follow-up of intra-arterial staphylokinase in 191 patients with peripheral arterial occlusion

Wild-type or equipotent variants of recombinant staphylokinase (rSak) were given intra-arterially (as a 2 mg bolus injection followed by an infusion of 1 mg/h or 0.5 mg/h overnight, with concomitant heparin [1000 IU/h]) to 191 patients of less than 80 years (62 +/- 1 years, mean +/- SEM), with a peripheral arterial occlusion (PAO) of less than 120 days (mean 14 +/- 1 days, median 11 days, 5 to 95 percentiles 3 to 30 days). Ninety nine patients presented with acute or subacute ischemia, 57 with severe claudication, 33 with chronic rest pain and 2 with gangrene. Occlusion occurred in 122 native arteries and in 69 grafts. Revascularization was complete in 83 percent (158/191), partial in 13 percent (24/191) and absent in 4 percent (7/191) after administration of 12 +/- 0.5 mg rSak over 14 +/- 0.7 h. Complete revascularization of acute occlusions of popliteal or more distal arteries was less frequent (60 percent, 15/25) than of acute occlusions of more proximal native arteries (95 percent, 37/39, p <0.001) or grafts (89 percent, 50/56, p = 0.005). Additional endovascular procedures were performed in 47 percent and subsequent elective bypass surgery in 23 percent of patients. Major bleeding occurred in 12 percent (23/191), one month mortality was 3.1 percent (6/191) and one year mortality was 6.9 percent (12/174). However, four patients (2.1 percent) had an intracranial bleeding following therapy: a 85 year old woman with severe diabetic arteriopathy, who was included in violation of the protocol, a 79 and a 74-year-old woman and a 74-year-old man, all with severe hypertension and limb threatening ischemia; these four patients died within two months after treatment. Amputations were performed within the first year in 16 of 162 surviving patients (9.8 percent): in 7 percent (7/96) with an occluded native artery and 14 percent (9/66) with an occluded graft (p = 0.19). No significant difference in lysis rate, one month mortality or one year amputation-free survival was observed in occlusions of recent onset (< or =14 days, n = 126) as compared to occlusions of longer duration (>14 days, n = 65). Treatment was interrupted prematurely in 4 patients because of a suspected allergic reaction. Fibrinogen levels remained unaffected during treatment (3.3 +/- 0.1 g/l before vs. 3.3 +/- 0.1 g/l after infusion, n = 167). In conclusion, rSak appears to be a highly effective thrombolytic agent in patients with PAO, resulting in a low one month mortality (3.1 percent) and a high one year amputation free survival (84 percent), with an acceptable incidence of major bleedings, but with occasional fatal intracranial hemorrhages.

Thrombolysis in arterial occlusion

Intra-arterial thrombolytic therapy has replaced systemic intravenous infusion of thrombolytic agents as a treatment modality for arterial occlusion in the limbs. Several catheter-guided techniques and various infusion methods and schemes have been developed. At present there is no scientific proof of definite superiority of any agent in terms of efficacy or safety but clinical practice favours the use of urokinase or alteplase. Studies which compared thrombolysis to surgical intervention suggest that thrombolytic therapy is an appropriate initial management in patients with acute occlusion of a native leg artery or a bypass graft. Underlying causative lesions are treated in a second step by endovascular or open surgical techniques. Severe bleeding is the most feared complication: the risk of hemorrhagic stroke is 1-2%.

Is transcranial Doppler useful in the detection of internal carotid artery cross-clamp intolerance?

The aim of this study was to test the hypothesis that a drop in the systolic blood flow velocity in the middle cerebral artery of 70% or more, measured by transcranial Doppler, is a better criteria in the detection of cross-clamp intolerance than electroencephalogram (EEG) and somatosensory evoked potential (SSEP) monitoring. After exclusion of patients with a recent stroke, urgent procedures and combined procedures, a transcranial Doppler with compression test was scheduled in 85 patients. In 13 patients the drop was 70% or more and in these patients a transcranial Doppler was also performed during the reconstruction of the internal carotid artery (the study group) under general anaesthesia. A shunt was used because of EEG and SSEP abnormality in one patient. No changes were observed in the remaining patients and no intraoperative strokes were seen. The transcranial Doppler monitoring was unreliable in three patients. During cross-clamp, the systolic blood flow velocity in the middle cerebral artery dropped less than 70% in four and 70% or more in six patients. It is concluded that using a drop of 70% or more of the systolic blood flow velocity in the middle cerebral artery during internal carotid artery cross-clamp, as an indicator of cross-clamp intolerance, will lead to unnecessary shunting.

[Epidemiology and prognosis of peripheral obliterative arteriopathy]

Peripheral arterial disease has received less attention from epidemiologists than coronary and cerebrovascular disease. Prevalence and incidence data typically show that peripheral arterial disease increases with age, is more common in men than women, and that symptomatic disease is only the tip of the iceberg. Studies concerning the prevalence of peripheral arterial disease rely mainly on the Rose questionnaire, which is used to screen for intermittent claudication, and on the ankle/brachial index, used to detect asymptomatic disease. Although there is a certain parallel between the 2 sets of data, the figures for asymptomatic disease consistently surpass those for clinical disease, and there is a wide variation between frequencies obtained in individual studies. In general, the prevalence of peripheral arterial disease is estimated to be under 2% for men aged less than 50 years, increasing to over 5% in those aged more than 70 years. Women reach these rates almost 10 years after men, although this gender difference decreases with increasing age. Figures for incidence follow a similar trend. The incidence of chronic critical ischaemia is estimated to be between 0.05% and 0.1% of the population. Asymptomatic disease detected with noninvasive tests is 3 to 4 times more frequent than intermittent claudication: its prevalence increases from under 5% for individuals aged less than 50 years to over 20% for individuals aged more than 70 years. The classical risk factors for atherosclerosis also apply to peripheral arterial disease, although their order of importance may be different from that for coronary and carotid disease. Several studies have shown that peripheral arterial disease correlates most strongly with cigarette smoking. Smoking is also the single greatest predictor of the progression of peripheral arterial disease. Other risk factors include hypertension, raised lipid levels (cholesterol and triglycerides for severe disease), diabetes, increased plasma viscosity, fibrinogen and homocysteine levels. Divergent views have been expressed in individual epidemiological studies with regard to the respective contribution of these risk factors to the development and progression of peripheral arterial disease. The natural history of peripheral arterial disease is characterised by a relatively benign local evolution. It can be estimated that, in general, 3 of 4 men presenting with intermittent claudication will never have a serious problem necessitating vascular intervention, and that no more than 5% are ever likely to require a major amputation. However, the underlying atherosclerotic pathology progresses with time: nondiseased arteries become obliterated and disease with an initially unilateral pattern frequently progresses to become bilateral. In addition, the few patients who do progress to critical ischaemia are at a significantly higher risk of amputation. The general prognosis for patients with peripheral arterial disease is particularly negative. There is a high prevalence of coronary heart disease and cerebrovascular disease in such patients, although the exact percentages depend on the patient population selected and on the method used for their evaluation. Coronary heart disease is detected in 40 to 60% of patients through a medical history combined with electrocardiography, while systematic coronary angiography detects coronary heart disease in 90% of those undergoing surgery. Although few patients with peripheral arterial disease have a history of stroke, in studies of surgical patients almost 30% appear to have significant extracranial disease. Patients with peripheral arterial disease have a poor life expectancy: the mortality rate is 3 to 5% per year in those with intermittent claudication and 20% per year in those with critical ischaemia. Coronary heart disease accounts for half of the total mortality, while vascular disease in general accounts for almost two-thirds.

The use of low-molecular-weight heparins in cardiovascular disease

Unfractionated heparin (UFH) has been used for decades as an effective and relatively inexpensive agent in the prevention of venous and arterial thromboembolic events. Low-molecular-weight heparin (LMWH) preparations are obtained by chemical or enzymatic depolymerization of unfractionated commercial grade heparin; their mean molecular weights range from below 4,000 to about 6,500 D (Table 1). Their mechanism of antithrombotic action is basically similar to that of UFH - binding to antithrombin to inhibit activated coagulation factors - but they have a different relative potency (to some extent also inter-individually) of anti-Xa versus anti-IIa activity. Shorter fragments which contain the essential pentasaccharide to bind to antithrombin but lack the required chain length to bind at the same time to thrombin, only inhibit activated Factor X. Fragments above 5,000 D which contain the pentasaccharide maintain their property to inhibit Factor Xa but with increasing chain length, they become stronger inhibitors of thrombin. LMWHs have little or no effect on global tests of blood coagulation such as the activated partial thromboplastin time when used in prophylactic or therapeutic dosages. A specific assay of anti-Xa activity is required to monitor biological activity but this is rarely needed. The main advantage of LMWHs for clinical practice derive from their pharmacokinetic properties. UFH binds to plasma proteins, endothelial cells and platelets. This saturable mechanism clears heparin rapidly from the circulation (the plasma half-life is non-linearly dose-related) and is held responsible for the large variation from person to person and from moment to moment in biological and clinical response. LMWHs bind far less to these elements and therefore have a 2 to 4-times longer plasma half-life, a markedly better bioavailability when injected subcutaneously and a more stable dose response. They also have a lower toxic effect in terms of heparin-induced thrombocytopenia which may be related to their lesser interaction with platelets.

Doppler flowmetry in the planning of perforator flaps

Perforator flaps have become the first choice in free flap reconstruction of contour defects or skin and fat replacement in our department. The Deep Inferior Epigastric Perforator (DIEP), the Superior Gluteal Artery Perforator (S-GAP) and the Thoracodorsal Artery Perforator (TAP) flaps are now routinely used. By evaluating the vascular anatomy of these flaps preoperatively, we intend to improve our surgical strategy so that these operative procedures can proceed in a faster and safer way. In this study, the results of the colour Duplex scanning in 50 consecutive DIEP flap patients are reviewed and evaluated for their sensitivity and positive predictive value. Also the preoperative information from unidirectional Doppler flowmetry in 30 S-GAP flaps and 11 TAP flaps is evaluated for its reliability. Due to the variable vascular anatomy of the lower abdominal wall and the dorso-lateral thoracic wall we now prefer using the colour Duplex scanning for planning the DIEP and TAP flaps. The more constant course of the branches of the superior gluteal artery allows us to use the easier and cheaper unidirectional Doppler flowmetry for planning the S-GAP flap.

Feasibility study of catheter-directed thrombolysis with recombinant staphylokinase in deep venous thrombosis

The feasibility of catheter-directed thrombolysis with recombinant staphylokinase was evaluated in six selected patients with deep vein thrombosis. The patients underwent intrathrombus infusion of recombinant staphylokinase (2 mg bolus followed by a continuous infusion of 1 mg/h). Heparin was given via the catheter as a bolus (5000 U) and as a continuous infusion (1000 U/h). Complete lysis was obtained in five patients and partial lysis in one patient. Complications consisted of minor bleeding in four subjects. Symptomatic reocclusion occurred in one. Debulking of the thrombus mass by a high speed rotating impeller (n = 1) and stenting (n = 3) were used as additional interventions. An underlying anatomical abnormality was present in two patients. Long term follow up revealed normal patency in all patients and normal valve function in four patients. Symptomatic venous insufficiency with valve dysfunction was present in the two with a second thrombotic episode. Thus catheter-directed infusion of recombinant staphylokinase in patients with deep vein thrombosis appears feasible and may be associated with a high frequency of thrombolysis. Larger studies to define the clinical benefit of this treatment appear to be warranted.

Catheter-directed lysis of iliofemoral vein thrombosis with use of rt-PA

The aim of our study was to evaluate the results of catheter-directed thrombolysis and complementary procedures to treat acute iliofemoral deep vein thrombosis (DVT). A total of 24 consecutive patients with acute iliofemoral DVT underwent intrathrombus drip infusion of alteplase (3 mg/h; mean dosage 86 mg, range 45-174 mg), while intravenous heparin (1000 U/h) was continued. Complementary procedures were hydrodynamic thrombectomy in 3 and primary insertion of a Wallstent in 9 patients. Patency of 19 thrombosed veins (79 %) was restored with prompt symptomatic relief. An underlying anatomical anomaly or lesion was present in 13 patients: iliac vein compression syndrome (n = 8), absent (n = 2) or obstructed (n = 1) vena cava or venous stenosis (n = 2). Ten of the abnormalities were unknown before lysis and eight were relieved by stent deployment. Puncture site bleeding was the only complication but led to transfusion in 6 patients (25 %). Symptomatic reocclusion occurred in 4 patients. Catheter thrombolysis of iliofemoral vein thrombosis revealed many anatomical abnormalities which may predispose to thrombosis and are often amenable to stenting.

[Rt-PA thrombolysis in the treatment of massive pulmonary embolism]

We present the case of a young comatose female patient in whom a massive pulmonary embolism was diagnosed by pulmonary angiography. During the angiography, not only successful thrombolytic therapy with recombinant human tissue-type plasminogen activator (rt-PA) (100 mg) was performed, but measuring of the pulmonary artery pressures, oxygen and carbon dioxide levels was also possible. Thrombolysis seems to be a good alternative to surgical thrombectomy.

[Cockett syndrome. Initial results with percutaneous treatment in 6 patients]

Intimal hypertrophy with venous spur formation caused by compression of the left common iliac vein by the right common iliac artery is advanced as the etiology of the higher incidence of deep venous thrombosis involving the left leg. In most cases of left iliofemoral thrombosis no underlying compression syndrome is detected or treated because the left common iliac vein has to be cleared from thrombi before compression can be identified. A series of 6 consecutive retrospectively analyzed patients with acute left iliofemoral thrombosis is presented. In these patients a left iliac vein compression syndrome was detected after percutaneous intraluminal thrombolysis with Actilyse (rt-PA). This compression was successfully relieved by insertion of a wall stent. Percutaneous treatment of Cockett's syndrome seems an attractive alternative for conservative and/or surgical management.

Predictive value of nailfold capillaroscopy in the diagnosis of connective tissue diseases

We revised the clinical files of 326 patients who underwent nailfold capillaroscopy. These patients could be subdivided into 4 groups: I: patients with clinical suspicion of connective tissue disease, II: patients with isolated Raynaud's phenomenon, III: patients with existing connective tissue disease, IV: patients with acrocyanosis, chronic pernio or related disorders. The presence of megacapillaries was noted. The sensitivity of their presence for the various categories of connective tissue disease was as follows: systemic sclerosis (n = 11): 100%, CREST (n = 15): 73%, MCTD (n = 9): 56%, dermatomyositis (n = 7): 86%. Nineteen patients with megacapillaries had no final diagnosis of connective tissue disease (specificity 93.3%). The positive predictive value of the presence of megacapillaries for a scleroderma spectrum disorder (SSD) was 63.5% and the negative predictive value of a normal capillaroscopy 96.7%. We conclude that nailfold capillaroscopy can be advised to rule out SSD's.

Thrombolytic therapy of peripheral arterial occlusion with recombinant staphylokinase

BACKGROUND

Recombinant staphylokinase (STAR) induces fibrin-specific coronary artery recanalization in patients with evolving myocardial infarction. The present pilot study evaluates its thrombolytic efficacy, safety, fibrin specificity, and immunogenicity in patients with peripheral arterial occlusive disease.

METHODS AND RESULTS

Thirty patients (37 to 86 years of age) with angiographically documented thromboembolic peripheral arterial occlusion of recent origin (21 +/- 5.5 days, mean +/- SEM) were treated with heparin and intra-arterial STAR given as a 1-mg bolus followed by a 0.5-mg/h infusion in 20 patients or as a 2-mg bolus followed by a 1-mg/h infusion in 10 subsequent patients. With 7.0 +/- 0.7 mg STAR infused over 8.7 +/- 1.0 hours, recanalization was complete in 25 patients, partial in 2, and absent in 3. Two major hemorrhagic complications occurred: one fatal hemorrhagic stroke and one hypovolemic shock caused by bleeding at the angiographic puncture site. Administration of STAR did not induce fibrinogen breakdown or a significant prolongation of template bleeding time. STAR-neutralizing activity and anti-STAR IgG were low at baseline, increased markedly from the second week on, and remained elevated for several months.

CONCLUSIONS

Intra-arterial administration of STAR restores vessel patency in patients with peripheral arterial occlusion in the absence of fibrinogen degradation.

External iliac artery fibrodysplasia

We report a patient in the "atherosclerotic age" with symptomatic fibromuscular hyperplasia of both external iliac arteries. Our patient had a history of bilateral intermittent claudication secondary to a concentric narrowing of a long segment of both external iliac arteries. A typical associated involvement of both internal carotid arteries was present.

A comparative trial of a low molecular weight heparin (enoxaparin) versus standard heparin for the prophylaxis of postoperative deep vein thrombosis in general surgery

BACKGROUND

Various studies have been performed in general surgery patients comparing low molecular weight heparin (LMWH) with standard heparin (SH) for the prevention of postoperative deep vein thrombosis (DVT), revealing contradicting results. Therefore, we have compared the efficacy and safety of a LMWH for the prevention of DVT after major general surgery.

PATIENTS AND METHODS

Patients received either 20 mg LMWH (enoxaparin) once daily, or 5,000 IU SH TID, starting preoperatively in a prospective, randomized, double-blind international multicenter trial. DVT was diagnosed using fibrinogen I 125 leg scanning. Major and minor bleeding were assessed clinically.

RESULTS

A total of 718 patients were randomized to LMWH, and 709 patients to SH. DVT was detected in 58 LMWH-treated patients (8.1%, 95% confidence interval [CI] 6.2% to 10.3%) and in 45 patients allocated to SH (6.3%, 95% CI 4.7% to 8.4%, P > 0.05). Major bleeding complications occurred in 11 LMWH-treated patients (1.5%, 95% CI 0.8% to 2.7%) and in 18 patients to whom standard heparin was administered (2.5%, 95% CI 1.5% to 3.9%, P > 0.05). Four LMWH-treated patients (0.6%) required reoperation for bleeding as compared to 13 patients in the SH group (1.8%, P = 0.03).

CONCLUSION

This LMWH appeared as effective and safe as SH. In view of its more convenient way of administration, this LMWH might be preferred for thromboprophylaxis.

Atheromatous embolization precipitated by oral anticoagulants

Five patients with a "blue or purple" toe syndrome due to atheromatous embolization probably precipitated by oral anticoagulant therapy are reported. In four, the symptoms started a few weeks after initiation of oral anticoagulants and in the fifth they were clearly aggravated by coumarinic drugs. Prior to anticoagulation, one patient had received a course of thrombolytic therapy and two had undergone an arterial catherization without embolic events. A diagnostic arteriography performed in four patients caused no new symptoms. All patients had advanced atherosclerosis. A shaggy aorta and/or pelvic arteries were found in four and in the fifth a highly stenotic femoral lesion appeared the source of peripheral embolization. Oral anticoagulants were interrupted in all five and four underwent reconstructive vascular surgery to eradicate the nidus of atheromatous emboli. One died postoperatively from multiple organ failure. The poor condition of the fifth patient precluded aorto-iliac surgery. No new episodes of embolization occurred and the symptoms disappeared, although one patient needed a toe amputation for a skin lesion that had proceeded to gangrene. The possible role of anticoagulant drugs in precipitating atheromatous embolization is discussed and the importance of recognizing the syndrome is emphasized.

Local thrombolysis for occluded arterial grafts: is the yield worth the effort?

This study reports the results and complications of local thrombolytic therapy of 50 recently occluded grafts. These occurred in 41 patients with acute severe but still reversible ischemia. The majority were infra-inguinal synthetic grafts. Thrombolysis was induced with urokinase (n = 1), streptokinase (n = 11) or alteplase (n = 38) via an intra-arterial catheter. Complete angiographical lysis was obtained in 36 grafts (72%) and partial lysis in 6 (12%). The highest lysis rate was obtained with alteplase (32/36; 89%). Complementary endovascular and/or surgical intervention was needed in 17 patients to correct an underlying stenosis and/or to save the limb. Fifteen complications occurred (30%) of which distal embolization (n = 4) and bleeding (n = 8 of which 3 fatal) were the most frequent. Six of the bleeding episodes occurred in patients on chronic aspirin intake. The late results were poor. At six months, the primary patency of successfully lysed grafts dropped to 19% and the limb salvage rate to 64%. Thrombolytic therapy is far from the ideal management of thrombosed grafts: maintenance of restored patency is the challenge.

Cobalamin absorption and serum homocysteine and methylmalonic acid in elderly subjects with low serum cobalamin

We prospectively studied 41 consecutive elderly patients with serum cobalamin (vitamin B12) levels lower than 125 pmol/l. The protein-bound cobalamin absorption test (PBAT) was performed in 34 of them and in 27 selected elderly control patients. The lower decision limit was 0.18% and an abnormal test was detected in only 9 (26%) of the 34 patients with low serum cobalamin level. When the PBAT was compared to the Schilling (Dicopac method) test, a concordant result was found in 80%. Serum methylmalonic acid and/or total homocysteine concentrations were elevated in 75% (26/35) of the patients with low serum cobalamin levels but also in 30% (5/17) of the control patients. Of the 12 and 9 cobalamin-deficient patients with elevated serum levels of methylmalonic acid and homocysteine, normalization after cobalamin therapy was obtained in 11 and 5 respectively. In conclusion, determination of serum metabolites and their response to cobalamin therapy are a sensitive index of significant cobalamin deficiency and a useful means of distinguishing between cobalamin and folate deficiency. The PBAT offers little advantage over the Schilling test in diagnosing cobalamin malabsorption in elderly patients.

Prevention of venous thromboembolism after surgery: a review of enoxaparin

This review discusses the problem of deep vein thrombosis (DVT) after operation and identifies three levels of risk of DVT: low (less than 10 per cent), moderate (10-40 per cent) and high (40-80 per cent). Special emphasis is placed on the most recent prophylactic treatment, low molecular weight heparins (LMWHs), particularly enoxaparin. Several LMWHs are now available, but they differ slightly and each must be evaluated on its own merits. In general, however, LMWHs are both effective and safe in those patients at moderate or high risk of DVT. Thromboprophylaxis is cost effective when analysed using health-economic methodology.

Prevalence and causes of anaemia in a geriatric hospitalized population

Of 732 consecutive patients admitted to an acute geriatric ward, 178 (24%) were found to be anaemic (haemoglobin of 115 g/l or below). An appropriate cause responsible for anaemia was identified in 83%. The anaemia of chronic disorders (ACD) (35%) and iron deficiency anaemia (15%) were the commonest causes. The spectrum of disorders associated with ACD is much broader than the classical category of infectious, inflammatory and malignant disorders. The relatively high prevalence of the myelodysplastic syndrome (5%) is striking and this syndrome as a cause of anaemia in geriatric patients deserves more attention than it has so far received. No obvious cause was found in 17%. The clinical significance of this finding remains unclear.