Is thrombophilia a major risk factor for deep vein thrombosis of the lower extremities among Lebanese patients?

AIM: Factor V Leiden (R506Q) mutation is the most commonly observed inherited genetic abnormality related to vein thrombosis. Lebanon has one of the highest frequencies of this mutation in the world with a prevalence of 14.4% in the general population. The aim of this study is to define risk factors including inherited genetic abnormalities among Lebanese patients with lower extremity deep vein thrombosis. We report the clinical outcome of patients with thrombophilia. METHODS: From January 1998 to January 2008, 162 patients (61 males and 101 females) were diagnosed with lower extremity deep vein thrombosis. Mean age was 61 years (range: 21 to 95 years). RESULTS: The most frequent risk factors for vein thrombosis were surgery, advanced age, obesity, and cancer. Twenty-five patients had thrombophilia, 16 patients had factor V Leiden (R506Q) mutation, and seven patients had MTHFR C677T mutation. Ninety-two percent of patients screened for thrombophilia were positive. Screening was requested in young patients (16), patients with recurrent (11), spontaneous (8), and extensive (5) venous thrombosis, familial history (5), pregnancy (4), estroprogestative treatment (3), and air travel (1). Nine patients had one, 11 patients had two, and five had three of these conditions. Follow-up (6 to 120 months) of these 25 patients treated with antivitamin K did not reveal recurrences or complications related to venous thromboembolism. CONCLUSION: Factor V Leiden mutation followed by MTHFR mutation are the most commonly observed genetic abnormalities in these series. Defining risk factors and screening for thrombophilia when indicated reduce recurrence rate and complications. Recommendations for thrombophilia screening will be proposed.

Factor V R506Q mutation-Leiden: an independent risk factor for venous thrombosis but not coronary artery disease.

BACKGROUND: A specific point G-A transition at nucleotide position 1691 in the factor V (FV) gene, FV-Leiden, was associated with increased risk of venous thromboembolism (VTE). Insofar as the association of FV-Leiden with coronary artery disease (CAD) remains poorly defined, the aim of this study was to determine the prevalence of FV-Leiden in a sample of 68 VTE patients, 69 CAD patients, and 192 randomly selected healthy subjects. METHODS: Total genomic DNA was extracted from the peripheral blood of study subjects and was used for PCR analysis. The presence (or absence) of FV-Leiden was assessed by PCR using primers flanking the mutant site (nt 1691), followed by hybridization with wild-type ('G') and mutant ('A') biotinylated DNA probes; detection was by DNA enzyme immunoassay (DEIA). RESULTS: While the prevalence of FV-Leiden in CAD patients was not statistically different from that of healthy subjects (14.5 % vs. 15.1 %; P=0.890, odds ratio 0.95; 95 % confidence interval 0.43--2.06), a significant increase in FV-Leiden prevalence was seen in VTE patients (70.6 % in VTE patients; P<0.001, odds ratio 13.4, 95 % confidence interval 6.9--25.8). Of the 48 VTE patients who tested positive for FV-Leiden, 42 were heterozygotes (G/A), while 6 were homozygotes (A/A) (allele frequency 0.397). All 10 CAD patients positive for FV-Leiden were heterozygote carriers (allele frequency 0.072). While gender was not a factor in FV-Leiden expression, higher prevalence in FV-Leiden was seen in younger (< or =45 years) VTE patients (38/51 vs. 10/17). CONCLUSION: FV-Leiden is a major inherited risk factor for VTE, with a peak incidence in younger patients, but does not appear to play any role in CAD pathogenesis in the population studied.

The prevalence of factor V R506Q mutation-Leiden among apparently healthy Lebanese.

Resistance to activated protein C (APC) degradation caused by a specific point mutation in the factor V (FV) gene, FV:R506Q or FV-Leiden, which replaces Arg506 with Gln at the APC cleavage site within the FV gene, is the most prevalent inherited caused of venous thrombosis. Recent reports suggested that the prevalence of FV-Leiden is high among Caucasians, and very low among non-Caucasians, thereby suggesting that FV-Leiden has originated as a single event in a primary focus. Insofar as FV-Leiden is associated with increased risk of thromboembolic diseases, coupled with its selective worldwide distribution, the aim of this study was to determine the prevalence of FV-Leiden in Lebanon and compare it with those of other countries of Caucasian and non-Caucasian origin. FV-Leiden was determined by PCR, followed by hybridization with specific wild-type and mutant DNA probes. By screening 174 healthy Lebanese subjects, 25 were shown to carry the FV-Leiden mutation, giving an allele frequency of 7.4% and an overall prevalence rate of 14.4%. Of the 25 FV-Leiden carriers, 24 were in the heterozygous state while one was in the homozygous states. No statistical difference in the FV-Leiden prevalence was noted with respect to age, gender, or sect. In addition to Lebanon, which had the highest prevalence rate reported thus far (14.4%), a high prevalence of FV-Leiden was reported for Syria (13.6%), Greece-Cyprus (13.4%), and Jordan (12.3%), an indication that the Eastern Mediterranean is the primary focus of FV-Leiden mutation. The high prevalence of FV-Leiden in Lebanon suggests that screening for this mutation must be considered for those with a family history, and/or those with additional risk factors for venous thrombosis.

Arteriovenous fistula for chronic hemodialysis in children.

Each year, three to five children per million develop chronic renal failure. Of these one to two will require long-term hemodialysis support. From July 1992 to July 2000, we performed 19 surgical procedures to provide chronic hemodialysis access for a group of 14 children. There were 8 boys and 6 girls, with a mean age of 7.9 years (range 2.5-13). Ten of the children were between 2.5 and 10 years old. The mean weight of the children was 20.3 kg (range 12-49). Four children were only 12 kg in weight. The mean follow-up period was 42.1 months (range 10-96). Surgical technique was varied. Polytetrafluoroethylene (PTFE) grafts were used in 5 cases. The overall mean functional primary patency of the fistula was 30.2 months and secondary patency 31.6 months. Primary and secondary patency were better with autologous (39 and 40.6 months) than with PTFE graft (3.75 and 4.75 months). Providing dialysis access in the pediatric population is a time-consuming and frustrating challenge. We advocate the use of autologous material whenever possible. In children less than 12 kg in weight, brachiobasilic fistula is our first choice for angioaccess.

Brachial to internal jugular vein bypass. A case report.

The introduction of percutaneous dialysis catheter placement in the subclavian vein for temporary dialysis has contributed to the high incidence of occlusion of axillary and subclavian veins. We report the case of a 62-year-old male patient who had a history of a chronic dissection of the thoracic and abdominal aorta and who was on hemodialysis for chronic renal failure through a right radio-cephalic fistula. The patient complained of recurrent thrombophlebitis of the right upper extremity secondary to a subclavian vein thrombosis after catheter placement. A brachial to internal jugular vein bypass using ring 6 mm polytetrafluoroethylene graft was performed to alleviate the symptoms of venous hypertension and to preserve the function of the radio-cephalic fistula. This bypass is still patent 24 months after surgery. Many recent studies showed promising results with this bypass favouring its use in selected patients with subclavian venous lesions not amendable with balloon angioplasty and thrombolytic therapy.

Digital pulse volume recording: an essential test for the assessment of arteritis in diabetic patients.

The high incidence of medial calcification in the distal arteries of lower extremities in diabetic patients is responsible for most of the errors made in measuring ankle-pressure index. Because digital arteries are rarely calcified, digital pulse volume recording has been proposed as a specific and complementary test. Between March 1993 and March 1996, this test was performed in addition to ankle-pressure index in 66 diabetic patients. The ankle-arm index was overestimated and erroneous in 89.4% of cases. Digital arteries were calcified in 74% of cases and diabetic neuropathy present in 53% of cases. Assessment of the severity of arteritis by digital pulse volume recording (category 1 to 5) has led to better prevention and treatment. It is an essential test for the assessment of arteritis in diabetics, but also for the prediction of success of a surgical procedure: distal amputation, lumbar sympathectomy and arterial reconstruction.

Malignant struma ovarii: report of two cases and selected review of the literature.

Malignant struma ovarii is an extremely rare tumor. Two new cases are described and current perspectives provided. Both cases are examples of the mixed form of the disease, and both were treated by surgery alone. One patient underwent total hysterectomy and bilateral salpingooophorectomy; the other had unilateral salpingo-oophorectomy. Both patients remained free of recurrent disease at 20 and 33 months from diagnosis. The controversies relating to therapy and diagnosis are discussed in detail.