Hypercoagulability--a new cofactor in the protein C anticoagulant pathway

An unusual case of warfarin-induced pinna skin necrosis

INTRODUCTION

Warfarin-induced skin necrosis is a rare but recognised complication of this drug. The condition predominantly affects the breasts, buttocks and thighs of obese, peri-menopausal women. We present the case of a patient with the condition in an unusual site, and we discuss the management challenges involved.

CASE REPORT

An 82-year-old man presented to the ENT department with a diagnosis of pinna haematoma. There was no history of trauma or infection. The patient was taking warfarin long-term for recurrent deep vein thrombosis. Two weeks prior to admission, the patient had had a loading course of warfarin following surgery. Multiple clinical teams were involved in treatment. The only abnormal laboratory investigation was a low protein S level; biopsy showed skin necrosis.

CONCLUSION

In this case, the unusual presentation created diagnostic confusion, and may have precipitated aggressive surgical debridement. However, a more conservative management strategy was used, which we would recommend in future.

Cutaneous necrosis induced by acenocoumarol

Cutaneous necrosis is an infrequent but well-documented complication of oral anticoagulants. In the pathogenesis of cutaneous necrosis induced by oral anticoagulants recent hypotheses favour the combined role of local factors and a transient unbalance of coagulation mechanisms leading to an hypercoagulable state. There exists a genetic factor that determines a decreased level of two vitamin-K dependent glycoproteins, namely protein C and protein S. We present the case of an obese woman that developed an extensive cutaneous necrosis while receiving acenocoumarol for a deep venous thrombosis. She had an heterozygous deficit for protein C. The histopathologic findings of vessel thrombi and red blood cell extravasation were consistent with the clinical picture. A biopsy specimen taken from an initial lesion disclosed images of leucocytoclastic vasculitis. We reviewed the literature focusing on the pathogenesis and the histopathology of the disease.

Serendipitous diagnosis of protein S deficiency

A 46-year-old male sought periodontal care for a swelling on his right mandibular gingiva. An excisional biopsy revealed a well-differentiated squamous cell carcinoma. Surgical treatment consisted of a right segmental mandibulectomy with ipsilateral right neck dissection and fibular free flap reconstruction. Two days after the surgical procedure, a weakened Doppler signal suggested vascular compromise of the graft. The patient was returned to the operating room where complete thrombosis of the internal jugular vein (recipient vessel) was observed. This event prompted a complete hematological evaluation that disclosed low serum levels of protein S. The patient was started on systemic heparin and local medicinal leeches. A week later, systemic warfarin sodium was added and successfully resolved the vascular compromise of the graft. Two years later, the patient is active and lives a full life with occasional adjustments of warfarin sodium. This case represents the first report on the treatment of gingival carcinoma that led to the serendipitous discovery of an unrelated and unusual systemic condition, protein S deficiency.

Prophylaxis of climbers for prevention of embolic accidents

The development of deep venous thrombosis and the ensuing secondary complications of pulmonary embolism, disseminated intravascular coagulation, and stroke may be produced in high altitude climbers as a result of acclimatization to altitude. To prevent these serious disorders, investigation for predisposing risk factors and consideration of anticoagulative therapy should be considered.

Predictors of left ventricular thrombus formation in patients with anterior myocardial infarction: role of activated protein C resistance

BACKGROUND

Left ventricular mural thrombus formation is a well-recognised consequence of acute anterior myocardial infarction. The vast majority of left ventricular thromboses occur in patients with anterior myocardial infarction and depressed left ventricular function.

OBJECTIVE

To evaluate the factors predicting left ventricular thrombus formation in patients similar for left ventricular function and left ventricular score indexes.

METHODS

We evaluated 45 consecutive patients who met the inclusion criteria of anterior myocardial infarction resulting in apical, anterior or septal asynergy (akinesia, dyskinesia), without non-Q-wave myocardial infarction, dilated cardiomyopathy, or renal or hepatic dysfunction. Patients were divided into two groups: group I with, and group II without, left ventricular mural thrombus. The groups were compared for clinical, echocardiographic and hematologic parameters (activated protein C resistance (APC-R), protein S and antithrombin III).

RESULTS

Smoking and ACP-R were significantly greater in group I than in group II (P < 0.05 and P < 0.005 respectively). Multivariate regression analysis showed that APC-R was an independent risk factor for left ventricular thrombus formation in the patient group selected. Antithrombin III and protein S concentrations were not statistically different between two groups. All other clinical and echocardiographic characteristics of the patients were similar in both groups.

CONCLUSION

APC-R is an independent risk factor for left ventricular thrombosis in patients with anterior myocardial infarction resulting in septal or anterior and apical akinesia or dyskinesia.

Obstetric implications of activated protein C resistance and factor V Leiden mutation

An increasing number of reports have focused on activated protein C resistance (APCR) as it has been shown not only to be the most common genetic factor predisposing patients to thromboembolic disease but the most common identifiable cause overall. More than 90 percent of the cases of APCR are caused by the factor V Leiden mutation, in which a guanine to adenine substitution in the factor V gene at nucleotide position 1691 results in a glutamine to arginine switch at position 506. Recent studies have also pointed to evidence of an association between APCR/factor V Leiden mutation and hypertensive disorders of pregnancy, first and second trimester miscarriage, placental infarction, and placental abruption.

Factor V Leiden and pulmonary embolism in a young woman taking an oral contraceptive

A 34-year-old woman with a history of asthma and oral contraceptive use died suddenly. Autopsy examination showed chronic pulmonary emboli with an acute pulmonary saddle embolus. An underlying congenital thrombophilic disorder was considered. Molecular studies on DNA isolated from blood using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis revealed coagulation factor V Leiden mutation. The incidence of venous thromboembolism in patients with factor V Leiden mutation and associated activated protein C (APC) resistance is discussed.

Prevalence of factor V Leiden (APCR) and other inherited thrombophilias in young patients with myocardial infarction and normal coronary arteries

OBJECTIVE

To investigate the role of activated protein C resistance (APCR, factor V Leiden) in coronary artery thrombosis.

METHODS

The prevalence of APCR and of congenital deficiencies of antithrombin III, protein C, protein S, plasminogen, and factor XII was investigated in adult patients under 45 years of age with acute myocardial infarction. The results were compared with those of a group of 53 age and sex matched control subjects.

RESULTS

Among 75 patients under the age of 45 years who were admitted from November 1994 to April 1996 for acute myocardial infarction, 22 (29.3%) had normal coronary arteriography (group I) and 53 (70.7%) had significant coronary artery disease (group II). Inherited thrombophilia was more often found in group I (4/22, 18.2%) than in group II (4/53, 7.5%) but the difference was not significant (F test: p = 0.22). The prevalence of APCR was 9.1% (2/22) in group I, 3.8% (2/53) in group 2 (p = 0.57), and 3.8% (2/53) in the normal control group (p = 0.57).

CONCLUSIONS

The prevalence of congenital thrombophilias, including APCR, does not seem to be increased in young patients with myocardial infarction and normal coronary angiograms, compared with young patients with coronary atherosclerosis and with normal control subjects. However, the statistical power of the study is too low to detect a significant difference and these results are published to allow a meta-analysis of this problem in the future.

Late-onset warfarin-induced skin necrosis: case report and review of the literature

Warfarin-induced skin necrosis is a rare complication of therapy with warfarin or other coumarin derivatives. When it occurs it usually appears 3 to 6 days after initiation of therapy and almost always between days 1 and 10. We report a case of late-onset (16 days after initiation of therapy) warfarin-induced skin necrosis and review the literature on this rarely reported variant of warfarin-induced skin necrosis. The skin lesion in our patient was not associated with either deficiency of protein C or resistance to activated protein C.

Prevalence of the factor V-Leiden mutation in four distinct American ethnic populations

Resistance to activated protein C (APC) is the most common risk factor for venous thromboembolism, a major cause of morbidity and mortality with an incidence of about 1/1,000 per year. The Arg 506 to Gln mutation in exon 10 of the coagulation factor V gene (factor V-Leiden) has been found to be responsible for over 90% of the APC resistance cases and is an autosomal dominant trait. Initial studies have suggested that this mutation is restricted to individuals of European Caucasian extraction with an average allele frequency in European and American Caucasians of 4.4%, making it one of the most common monogenic disorders in the Caucasian population. A limited number of other ethnic populations have been tested and the mutation has been found only rarely. In our multiethnic survey of 602 individuals, Hispanic-Americans had the highest observed frequency of the factor V-Leiden mutant allele, 1.65%, while African-Americans had a somewhat lower frequency, 0.87%. No factor V-Leiden mutations were found in 191 Asian-Americans or 54 Native-Americans tested. These results indicate that the factor V-Leiden mutation segregates in populations with significant Caucasian admixture and is rare in genetically distant non-European groups. This ethnic stratification may be important in developing cost-effective selective screening programs to identify individuals at risk for thromboembolism and offer prophylactic therapy.

The hypercoagulable state. Who, how, and when to test and treat

Patients with a family history of thrombosis, early-onset or recurring thrombosis, thrombosis at unusual sites, or warfarin-induced skin necrosis should be investigated for a possible underlying inherited hypercoagulable disorder. These include AT-III deficiency, protein C and S deficiencies, and APC resistance. Many patients should also be evaluated for the antiphospholipid syndrome, an acquired disorder. Functional assays are more useful than immunologic assays for diagnosing AT-III deficiency, protein C and S deficiencies, and APC resistance. A molecular probe is now available for the abnormal factor V most often responsible for APC resistance. Testing for the antiphospholipid syndrome involves assays for the lupus anticoagulant and anticardiolipin antibodies. AT-III and protein C concentrates are now available for short-term therapy. Long-term prophylactic administration of warfarin may have to be considered for some symptomatic patients with proven abnormalities, especially after more than one thrombotic event. While the management of asymptomatic persons remains controversial, the use of prophylactic anticoagulation should be anticipated for trauma, surgery, pregnancy, or other high-risk situations.

Toward molecular strategies for heart disease--past, present, future

The past two decades of cardiovascular biology and medicine have been based largely upon the consideration of the heart and vasculature as an integrated physiological system, a view that has resulted in major therapeutic advances. With the advent of developments of gene transfer, mouse and human genetics, genetic engineering of intact animals, and molecular and cellular technology, cardiovascular medicine is now on the threshold of a molecular therapeutic era. Major steps have been taken toward unraveling the molecular determinants of complex, integrative, and polygenic cardiovascular disease states, including atherogenesis, hypertension, cardiac hypertrophy and failure, congenital heart disease, and coronary restenosis following balloon angioplasty. Our improved understanding of the fundamental basis of these important cardiovascular disease processes has established a scientific foundation for diagnostic, prognostic, and therapeutic advances in the mainstream of cardiovascular medicine.

Hematologic disorders associated with ischemic stroke

Hematological disorders underlie a small proportion of all ischemic strokes. The association of these coagulation abnormalities with ischemic stroke is not always clear. The etiology of stroke still remains uncertain in a large number of cases and proper screening for coagulation abnormalities and the discovery of new coagulation disorders will probably increase the rate of strokes attributable to these causes. Since large case-control studies with unselected and consecutive stroke patients from different ethnic origins have not yet been performed to determine the role of coagulation abnormalities in ischemic stroke, our knowledge is dependent on case reports and small series of mostly younger patients. Extensive hematologic evaluation of unselected stroke patients will likely yield little useful information and be too expensive. Every stroke patients needs a careful evaluation, and in selected cases, this should include coagulation parameters. Patients with unexplained strokes after a careful evaluation, previous thrombotic episodes, or a positive family history for thrombosis, are good candidates for further coagulation studies. As long as the hypercoagulable state persists, both arterial and venous thromboembolic recurrences can be expected. Many of these patients may benefit from anticoagulants. In patients with hereditary coagulation disorders, studies should be extended to close relatives. Since some coagulation tests are fairly expensive, provide only equivocal data, and are not widely available, we advise a step-by-step approach starting with the patient and family history.

Resistance to activated protein C in healthy women taking oral contraceptives

Resistance to activated protein C (APC) is at present considered the most frequent laboratory abnormality in patients with deep-vein thrombosis. An increased risk for venous thrombosis is associated to the use of oral contraceptives (OC). We studied APC sensitivity in 50 healthy women taking OC and in 50 healthy controls, matched for age, smoking habit, educational and social levels, and the main biochemical routinary parameters. Subjects with a personal or familial history of thrombosis and also with chronic or acute diseases were excluded. Protein C, protein S, antithrombin III and lupus anticoagulant activity (LAC) were also evaluated. Increased fibrinogen and protein C levels, decreased protein S. and shortened PT and APTT were also observed in women taking OC. APC sensitivity ratio (APC-SR) was significantly lower in the OC group than in a control group (2.6 +/- 0.38 v 2.81 +/- 0.35, P < 0.01). Seven of eight women with APC ratio < or = 2 (APC resistant) were OC users: the difference of prevalence was statistically significant (chi-squared test, P < 0.05). Only two out of eight women were found heterozygous for the Leiden factor V mutation. Two APC-resistant women without the Leiden mutation subsequently discontinued OC and both then normalized their APC-SR. We conclude that acquired factors, i.e. oral contraceptives, may play an important role in determining plasma APC resistance.

Thrombosis and embolism

Prevention offers the best approach to limiting morbidity and mortality from deep vein thrombosis and pulmonary embolism in obstetric patients. The use of anticoagulant drugs during pregnancy, however, can be problematic, from the maternal or the fetal point of view. Deciding on the best management is further limited by the lack of controlled clinical trials in the obstetric setting. From the data available, it can be recommended that anticoagulant prophylaxis should be targeted at groups of patients at high risk of thrombosis during pregnancy and the puerperium. Heparin is the agent of choice in most situations during pregnancy for the prophylaxis of venous thrombosis, while warfarin is still the most effective agent for the prevention of systemic embolism from artificial cardiac valves. Prophylactic measures against venous thrombosis are probably underused in the puerperium. Controlled clinical studies are urgently required to optimize prophylaxis of venous thromboembolism associated with pregnancy, and large studies may be more feasible in the puerperium when the incidence of thromboembolism is highest.

Activated protein c resistance (APC) and inherited factor V (FV) mis-sense mutation in patients with venous and arterial thrombosis in a haematology clinic

BACKGROUND

Inherited factor V (FV) mis-sense point mutation has recently been identified as a major cause of familial venous thrombosis. The incidence of this congenital haemostatic disorder in Australia is unknown.

AIM

To examine the incidence of this congenital defect in patients with thrombosis attending a haematology clinic.

METHODS

Individuals investigated or treated for venous and arterial thrombosis over a four month period, as well as those who were on anticoagulant for valvular replacement or arrhythmia were studied for the presence of FV mis-sense point mutation, FV Q506 (G to A at nucleotide position 1691) by a polymerase chain reaction based test, and activated protein C (APC) resistance using an APTT based coagulation assay.

RESULTS

Forty-five patients with venous thromboembolism (VTE), 20 patients with coronary artery disease and 25 patients with valvular replacement or arrhythmia who were on anticoagulant were examined. The frequency of FV mis-sense point mutation in these three groups was 26.7%, 15% and 4% respectively. In this study, patients with FV Q506 were of a younger age and had a higher incidence of extensive thrombosis or recurrence as compared to those with the normal factor V gene. This mutation was found in a diverse group of people (four of the 12 patients were of non-European origin). Nearly 50% of these patients had other risk factors for VTE. The number of patients with a family history of VTE was similar for those with the FV mutation and the normal FV.

CONCLUSION

This study confirms the high incidence of FV Q506 mutation in patients with VTE reported overseas. Several clinical features, i.e. young age of onset of VTE, high recurrence rate, diverse ethnic background and importance of associated risk factors are highlighted. The findings in this study also raise the possibility that this mutation may be a risk factor for arterial thrombosis. Large studies are required to substantiate these findings.

Molecular genetics of venous thromboembolism

Venous thrombosis is often familial, but until recently well-defined genetic defects were only found in a minority of patients. The situation changed with the discovery of inherited resistance to activated protein C (APC) as a novel mechanism for familial thrombophilia. It is caused by a single point mutation in the factor V gene, which predicts replacement of Arg506 in the APC-cleavage site with a Gln. APC resistance is found in a majority of patients with familial thrombosis as well as in 3-7% of the general population. It afflicts affected individuals with a life-long increased risk of thrombosis. The factor V gene mutation is the most prevalent single gene defect associated with thromboembolic disease so far described.

Non-haemorrhagic adverse reactions of oral anticoagulant therapy

Oral anticoagulants are extensively used in everyday medical practice, especially for the prophylaxis of deep vein thrombosis and pulmonary thromboembolism. Bleeding is the major risk of such therapy. Although infrequent, however, non-haemorrhagic complications may also play a considerable role. The purpose of this paper is briefly to review the most important non-haemorrhagic adverse reactions and their clinical signs. Moreover, the pathogenetic hypotheses, the relationships with protein C and S levels, and the possibility of prevention and treatment are also discussed.

Dorsal vein thrombosis of the penis presenting to an STD clinic

OBJECTIVE

To describe the clinical assessment, diagnosis and differential diagnosis of dorsal vein thrombosis of the penis (DVTP) and to observe its natural course over time.

DESIGN

A descriptive study of six patients presenting with penile swelling to an STD clinic over a twenty month period.

SUBJECTS

Six male patients between the ages of 22 and 46 years who self-presented to an STD clinic in Perth, Western Australia during a period from October 1991 to June 1993.

METHODS

Initial history, examination and follow up were undertaken as routine for all STD clinic patients. This was supplemented with later exhaustive history taking; full cardiovascular, fundoscopic, abdominal and genital examination; blood screening for coagulation defects, glucose level, autoantibodies, ESR, urea, electrolytes, calcium, creatinine and liver function test; and duplex doppler ultrasound scanning.

RESULTS

No consistent abnormalities were detected on clinical examination, nor on blood testing. Ultrasound revealed one case of rupture of the corpus cavernosum, with haematoma and thrombus formation. There were two cases of pure DVTP demonstrable with ultrasound and two cases in which spontaneous resolution of clinical DVTP has occurred. The sixth patient declined further investigation and followup, but also displayed the clinical features of DVTP. Coagulation abnormalities as seen in elevated antithrombin III levels are of unknown significance.

CONCLUSIONS

DVTP and ruptured corpus cavernosum should be considered in the differential diagnosis of gradual onset penile swelling and/or deformity. Its natural course tends to be one of spontaneous resolution. No sexual or urinary symptoms or dysfunction were experienced, even in the presence of persistent thrombus. Directed and specific investigation only, depending on the clinical state of the patient, should be carried out.

Newer aspects of micronutrients in chronic disease: copper

Cu ions are pro-oxidants when added to biological material in vitro and excessive levels of Cu in the body, such as in Wilson's Disease (Yarze et al. 1992) promote oxidant-related pathologies. In contrast there is now substantial evidence that an optimum level of Cu is required to maintain antioxidant defence and that Cu deficiency in animals increases oxidant stress. There are abundant mechanistic relationships linking Cu deficiency and processes associated with IHD, some of which do not directly involve oxidant damage. These mechanistic relationships, however, have mostly been demonstrated in animal models and more information is urgently required concerning possible chronic mild Cu deficiencies in human populations. A major hurdle to advances in this area is the lack of indices of Cu status which are sensitive enough to detect marginal Cu deficiency in humans. The question, therefore, of whether or not there is a role for mild Cu deficiency in the onset of chronic disease processes, including IHD, remains unanswered.

Association of idiopathic venous thromboembolism with single point-mutation at Arg506 of factor V

Abnormal coagulation factor V may underlie the thrombotic events associated with resistance to activated protein C (APC). We analysed 27 consecutive patients with documented idiopathic (recurrent) thromboembolism for the occurrence of point mutations within the APC sensitive regions of blood coagulation factor V. In 10 patients we observed a single basepair mutation resulting in a substitution of Arg506 to Gln. This mutation was significantly linked to in-vitro resistance to APC in these subjects. This mutation at Arg506 of factor V may form the molecular basis for the thrombotic events associated with APC resistance.