Hydroxyurea for patients with essential thrombocythemia and a high risk of thrombosis

BACKGROUND

Abnormalities in the number and function of platelets may contribute to thromboembolic complications in patients with essential thrombocythemia. We assessed whether maintaining the platelet count below 600,000 per cubic millimeter with hydroxyurea reduces the incidence of thrombosis in patients with essential thrombocythemia and a high risk of thrombosis.

METHODS

A total of 114 patients with essential thrombocythemia (77 women and 37 men; median age, 68 years; range, 40 to 85) and a median platelet count of 788,000 per cubic millimeter (range, 533,000 to 1,240,000 per cubic millimeter) were randomly assigned to receive hydroxyurea (56 patients) or no myelosuppressive therapy (58 patients). Ninety-seven (85 percent) were over 60 years old, and 52 (46 percent) had had thrombosis. The two groups were matched for age, sex, and platelet count at randomization. Antiplatelet prophylaxis with aspirin or ticlopidine was not stopped. Follow-up lasted a median of 27 months in both groups.

RESULTS

Two patients (3.6 percent) treated with hydroxyurea had thrombotic episodes (one stroke and one myocardial infarction), whereas 14 patients (24 percent) in the control group had thrombotic episodes (one stroke, five transient ischemic attacks, five peripheral arterial occlusions, one deep-vein thrombosis, and two cases of superficial thrombophlebitis). The difference (20.4 percentage points; 95 percent confidence interval, 8.5 to 32 percent) was statistically significant (chi-square with Yates' correction, 8.3; 1 df; P = 0.003).

CONCLUSIONS

Hydroxyurea is effective in preventing thrombosis in high-risk patients with essential thrombocythemia.

The hypercoagulable states

Patients are considered to have hypercoagulable states if they have laboratory abnormalities or clinical conditions that are associated with an increased risk of thrombosis (prethrombotic states) or if they have recurrent thrombosis without recognizable predisposing factors (thrombosis-prone). The number of specific primary hypercoagulable states that are recognized is growing. These disorders are generally inherited abnormalities of coagulation in which a physiologic anticoagulant mechanism is defective: for example, antithrombin III deficiency, protein C and protein S deficiency, abnormalities of the fibrinolytic system, and dysfibrinogenemias. Secondary hypercoagulable states are generally acquired disorders in patients with underlying systemic diseases or clinical conditions known to be associated with an increased risk of thrombosis: for example, malignancy, pregnancy, use of oral contraceptives, myeloproliferative disorders, hyperlipidemia, diabetes mellitus, and abnormalities of blood vessels and rheology. The complex pathophysiologic features of these secondary hypercoagulable states are discussed, and a framework is provided for the laboratory investigation and systematic clinical approach to the patient.

Erythromelalgia caused by platelet-mediated arteriolar inflammation and thrombosis in thrombocythemia

Erythromelalgia was the presenting symptom in 26 of 40 patients with thrombocythemia in its primary form or when associated with polycythemia vera. The localized painful burning, redness, and warm congestion in the extremities could be accurately documented with thermography. Skin punch biopsy samples taken from the affected areas showed typical arteriolar inflammation, fibromuscular intima proliferation, and thrombotic occlusions. Erythromelalgia often progressed to ischemic acrocyanosis or necrosis in toes or fingers. Complete relief of pain and restoration of microvascular circulation disturbances was obtained with the cyclo-oxygenase inhibitors aspirin and indomethacin, but not with sodium-salicylate or the platelet inhibitors dipyridamole, sulfinpyrazone, ticlopidine, and dazoxiben. The erythromelalgia was alleviated during busulfan-induced remissions of thrombocythemia and its recurrence coincided with relapsing thrombocythemia. These observations suggest a causal relationship between erythromelalgia and thrombocythemia, in which platelet-mediated inflammatory and occlusive arteriolar changes play a part in the etiology of erythromelalgia.

Prognostic significance of thrombocytosis in patients with primary lung cancer

In patients with malignancies, thrombocytosis has previously been related to disease stage, histological type, and survival. In the present study, the prevalence of thrombocytosis and the prognostic information provided by platelet counts were analysed in a large cohort of patients with primary lung cancer. At the time of diagnosis, pretreatment platelet counts were retrospectively recorded in 1,115 consecutive patients with histologically proven primary lung cancer. All patients were reviewed regarding histological type, tumour, node, metastasis (TNM) classification stage and survival. The prevalence of thrombocytosis in patients with lung cancer was compared with that in a series of 550 consecutive out-patients with benign lung disorders. In 269 surgically resected patients, postoperative platelet counts were recorded 1-3 months after resection of the tumour. In the follow-up period, thromboembolic episodes diagnosed either clinically or at autopsy were recorded. The overall prevalence of thrombocytosis (> 400 x 10(9) platelets.L-1) in the patients with lung cancer was 32%. The frequency of thrombocytosis was significantly higher compared with the control subjects (32 vs 6%; p < 0.0001). Platelet counts differed significantly among subgroups defined by the TNM classification, with the proportion of patients with > 400 x 10(9) platelets.L-1 greatest in the more advanced TNM stages (stage I and II 23% vs stage III and IV 37%; p < 0.0001). Patients with thrombocytosis had a significantly poorer survival than patients with normal platelet counts (p < 0.0001). In a multivariate survival analysis (Cox model), thrombocytosis continued to correlate strongly with poor survival even when adjusted for histological type, sex, age, and TNM stage (p < 0.001). In surgically resected patients, the frequency of preoperative and postoperative thrombocytosis differed significantly (23.0 vs 8.9%; p < 0.0001). Survival rate was significantly reduced in patients with preoperative thrombocytosis (p = 0.005). Thrombocytosis was not associated with an increased incidence of thromboembolism. In conclusion, thrombocytosis is an independent prognostic factor of survival in patients with primary lung cancer. We suggest that platelet counts should be included in future multivariate analyses of survival in patients with lung cancer.

Effect of fondaparinux on platelet activation in the presence of heparin-dependent antibodies: a blinded comparative multicenter study with unfractionated heparin

Heparin-induced thrombocytopenia (HIT) is a complication of heparin therapy caused by antibodies against a complex of platelet factor 4 and heparin. Fondaparinux (Arixtra) is a new synthetic selective factor Xa inhibitor. We performed a serologic study to determine the cross-reactivity of HIT sera with fondaparinux. Using a prospective, blinded study design, 39 clinically and serologically confirmed sera from patients with HIT and 15 control sera were sent to 3 different laboratories, each of which specialized in a particular HIT assay. These include the serotonin release assay, heparin-induced platelet agglutination assay, and platelet aggregation assay. Two of 82 assays (2.4%) performed in the presence of control sera were positive, both with unfractionated heparin. In the presence of HIT sera, 75 of 94 (79.8%) evaluable assays were positive with unfractionated heparin; fondaparinux was significantly (P < .001) less reactive than unfractionated heparin, only 3 of 91 evaluable assays (3.3%) being positive. Using flow cytometry, unlike unfractionated heparin, fondaparinux did not induce the binding of PAC1 and anti-CD62 monoclonal antibodies or of annexin V to platelets with HIT sera. Together, these results suggest that fondaparinux is nonreactive to HIT sera and raise the possibility that the drug may be used for prophylaxis and treatment of thrombosis in patients with a history of HIT.

Risk factors for visual loss in giant cell (temporal) arteritis: a prospective study of 174 patients

OBJECTIVE

To determine the risk factors--especially the effects of thrombocytosis--for permanent visual loss in patients with temporal arteritis.

METHODS

One hundred seventy-four patients with temporal arteritis (147 biopsy proven) were prospectively observed for the development of permanent visual loss. We used multivariate logistic regression analysis to determine which of 17 pretreatment characteristics were associated with visual loss.

RESULTS

Visual ischemic manifestations occurred in 48 (28%) patients, including permanent visual loss in 23 (13%) patients. The independent predictors associated with an increased risk of permanent visual loss were a history of transient visual ischemic symptoms (odds ratio [OR] = 6.3; 95% confidence interval [CI]: 1.4 to 29; P = 0.02) and a higher platelet count (OR = 3.7 per SD; 95% CI: 1.8 to 7.9; P = 0.001). The presence of constitutional symptoms (OR = 0.14; 95% CI: 0.02 to 0.77, P = 0.01), polymyalgia rheumatica (OR = 0.04; 95% CI: 0.01 to 0.48, P = 0.02), and C-reactive protein level (OR = 0.35 per SD; 95% CI: 0.13 to 0.92, P = 0.03) were associated with a reduced risk. Upper limb artery involvement was excluded from the multivariate model, as no patients with that problem developed permanent visual loss. Of the 87 patients who presented with thrombocytosis (platelet count >400 x 10(9)/L), 32 (37%) developed ischemic visual symptoms, compared with 16 (18%) of those without thrombocytosis.

CONCLUSIONS

An elevated platelet count is a risk factor for permanent visual loss in temporal arteritis. The finding of thrombocytosis in a patient with suspected temporal arteritis should emphasize the need for urgent treatment, with consideration of using inhibitors of platelet aggregation or anticoagulation therapy.

Thrombocytosis associated with poor prognosis in patients with esophageal carcinoma

BACKGROUND

Thrombocytosis in patients with cancer has been reported to be associated with increased expression of angiogenic factors and with a poor prognosis in some types of cancer. The aim of this study is to analyze the clinicopathologic significance and prognostic value of platelet counts in patients with esophageal cancer.

STUDY DESIGN

Platelet counts were measured before surgery in 374 patients diagnosed between 1987 and 1999 with primary esophageal squamous cell carcinoma. We used the cut-off level of 293 x 10(9)/L (mean of 80 healthy controls +/- standard deviation) to define thrombocytosis. We analyzed the relationship between platelet counts, TNM factors, and white blood cell counts. Among 374 patients, the levels of C-reactive protein were analyzed in 170 patients and serum thymidine phosphorylase concentration was analyzed in 91 patients. The multivariate prognostic value of platelet counts, tumor size, and TNM factors were determined using Cox's proportional hazards model.

RESULTS

Platelet counts were significantly increased in patients with large tumors (p < 0.001), deep tumors, nodal involvement, and distant metastasis in univariate analysis. C-reactive protein level, white blood cell count, and serum thymidine phosphorylase concentration were also significantly increased in patients analyzed with thrombocytosis in univariate analysis. Adjusting for tumor size and TNM factors, multivariate analysis indicated that thrombocytosis as defined in this study was an independent prognostic factor (hazard ratio = 1.52, 95% CI = 1.11 to 2.08, p = 0.009).

CONCLUSIONS

A high platelet count is associated with tumor progression and poor survival in patients with esophageal carcinoma.

Unexplained pulmonary hypertension in chronic myeloproliferative disorders

AIM

To investigate the potential association between the chronic myeloid disorders (CMDs), including the chronic myeloproliferative disorders, and pulmonary hypertension (PH).

METHODS

Retrospective chart review of patients who had received diagnoses of both CMD and PH. Patients with a known cause of PH were excluded. The diagnosis of a CMD was based on established criteria. The diagnosis of PH was based on echocardiographic data or right heart catheterization data.

RESULTS

Twenty-six patients satisfied the criteria for both a CMD and PH. Twelve patients had myeloid metaplasia with myelofibrosis (MMM), 5 patients had essential thrombocythemia (ET), 6 patients had polycythemia vera, 2 patients had a myelodysplastic syndrome, and 1 patient had chronic myeloid leukemia. Twenty-two patients (92%) received treatment for their CMDs, which included therapy with hydroxyurea (18 patients), anagrelide (7 patients), and busulfan (3 patients). PH was diagnosed a median of 8 years after recognition of the CMD (range, 0 to 26 years). The median right ventricular systolic pressure (RVsys) was 71 mm Hg (range, 32 to 105 mm Hg). RVsys correlated with the platelet count in patients with MMM (r = 0.30) and ET (r = 0.6) and with the hemoglobin levels in patients with PV (r = 0.77). Treatment of CMD did not seem to affect the severity of the pulmonary artery pressures as measured by serial echocardiography. With a median survival time of 18 months after the diagnosis of PH, the cause of death in the majority of the patients was cardiopulmonary.

CONCLUSIONS

The current study suggests a higher than expected incidence of PH in patients with MMM, PV, and ET. Prognosis in such a setting is poor and may not be influenced by aggressive treatment of the underlying hematologic disorder.

Hematologic disorders and ischemic stroke. A selective review

More than a dozen primary hematologic disorders have been associated with ischemic stroke. Inherited deficiencies of antithrombin III, protein C, and protein S have been linked with stroke in case reports; optimal screening requires functional as well as antigenic assays. Antiphospholipid antibodies and lupus anticoagulants are the most frequently identified acquired states associated with ischemic stroke. Polycythemia vera, sickle cell anemia, sickle-C disease, and essential thrombocythemia are the major disorders of formed blood elements causing stroke. Special, step-wise screening for occult prothrombotic entities in stroke patients is recommended for young persons with stroke of uncertain cause, for those with prior venous thrombosis, for those with a family history of unusual thrombosis, and for those with no other explanation for recurrent stroke. Acquired, perhaps transient, abnormalities of platelets, coagulation inhibition, and fibrinolysis may contribute importantly to brain ischemia in synergy with other mechanisms, but at present these remain ill-defined. The contribution of prothrombotic diatheses to stroke is probably underrecognized and warrants further investigation.

Occurrence, etiology, and clinical significance of extreme thrombocytosis: a study of 280 cases

PURPOSE

To determine the etiology and to evaluate the clinical consequences of an extremely elevated platelet count.

PATIENTS AND METHODS

A review of the medical records was performed on all patients encountered during a 5 1/2-year period who had at least one platelet count of 1,000 x 10(9)/L or greater.

RESULTS

Of the total of 280 patients with extreme thrombocytosis (EXT), 231 (82%) had reactive thrombocytosis (RT), 38 (14%) had a myeloproliferative disorder (MPD), and 11 (4%) had cases of uncertain etiology. RT was more common than MPD in all age groups except those in the eighth decade and older. Symptoms of bleeding and/or vaso-occlusive phenomena were noted in association with EXT in 21 (56%) of the MPD patients but in only 10 (4%) of the RT patients. Treatment to lower the platelet count and/or inhibit platelet function was employed in 36 MPD patients and 23 RT patients. Eight patients with MPD and 34 with RT are known to have died, but no patient in either group is known to have died of a thrombotic or bleeding event when the platelet count was greater than or equal to 1,000 x 10(9)/L.

CONCLUSIONS

Platelet counts greater than or equal to 1,000 x 10(9)/L should not be considered rare events in the general, acute-care hospital population, and usually represent a reactive phenomenon.

Prospective study of the incidence and risk factors of postsplenectomy thrombosis of the portal, mesenteric, and splenic veins

HYPOTHESIS

Splenectomy is recognized as a cause of portal, mesenteric, and splenic vein thrombosis. The exact incidence of the complication and its predisposing factors are not known.

DESIGN

Prospective observational cohort study. The median follow-up time of the patients was 22.6 months.

SETTING

University surgical clinic in a teaching hospital.

PATIENTS

A total of 147 consecutive patients who underwent splenectomy in a 4-year period were enrolled in the study.

INTERVENTIONS

Preoperative and postoperative evaluation included ultrasonography with color Doppler flow imaging of the portal system, results of blood coagulation tests, fibrinogen levels, D-dimer levels, and complete blood counts. Operative sheets were recorded and reviewed. When portal system thrombosis (PST) was diagnosed, a complete control for acquired and congenital thrombophilia disorders was obtained.

MAIN OUTCOME MEASURES

Primary end points of the study were the assessment of the incidence of postsplenectomy PST and the identification of risk factors for its occurrence.

RESULTS

Portal system thrombosis occurred in 7 (4.79%) of 146 patients who underwent splenectomy. The age, sex, type or length of the operation, and use of preoperative and postoperative thromboprophylaxis with low molecular weight heparin did not prove to be significant factors in the occurrence of PST. Platelet count of more than 650 x 10(3)/microL and greater spleen weight (>650 g) was associated with the development of PST (P = .01, P = .03). Normal D-dimer levels on diagnosis of the complication showed a negative predictive value of 98%. Two of the affected patients were diagnosed with thrombophilia disorders. In a median follow-up period of 22.6 months, no other case of PST was recorded.

CONCLUSIONS

Postsplenectomy PST occurs in approximately 5% of patients. Possible risk factors are thrombocytosis, splenomegaly, and congenital thrombophilia disorders.

Thromboembolic risk of postsplenectomy thrombocytosis

Although thrombocytosis is a very common finding after splenectomy, the thromboembolic risk of postsplenectomy thrombocytosis has not been clarified. To our knowledge, this retrospective study of 318 patients without myeloproliferative disorders who underwent splenectomy is the largest of its type. Thrombocytosis developed in 75% of the patients. No substantial increase in the incidence of thromboembolism was detected in patients with thrombocytosis.

Portal vein thrombosis following splenectomy for hematologic disease: prospective study with Doppler color flow imaging

We report the results of a prospective series of 60 consecutive splenectomies for hematologic disorders performed between February 1995 and May 1996. The portal venous flow of all the patients (34 men and 26 women with a mean age of 54.1 years) was systematically studied before and after intervention with Doppler color imaging (on the day before the intervention and on the 7th and 30th postoperative days). The objective of this study were to determine the real frequency of asymptomatic portal or splenic venous thrombosis (PSVT) after hematologic splenectomy. The intervention began with exteriorization of the spleen and the tail of the pancreas; ligation of the splenic vein was performed close to its junction with the inferior mesenteric vein. Twenty-three complications (38.3%) were noted with three deaths (5%). One symptomatic PSVT (1.6%) and three asymptomatic PSVTs (6.7%) were diagnosed and treated with no deaths. Three risk factors of PSVT, recognized by all the authors, were present in these four cases: large splenomegaly, thrombocytosis, or myeloproliferative disorder. The systematic ultrasonographic (US) examinations increased the frequency of diagnosis of PSVT sevenfold during the perioperative period. Patients with marked splenomegaly associated with lymphoma, chronic lymphocytic leukemia, or myeloid metaplasia probably require systematic US monitoring during follow-up, but this must be determined by further study.

Platelet hyperaggregability and thrombosis in patients with thrombocythemia

The relation between platelet hyperaggregability and thrombosis was assessed in 28 patients with thrombocythemia due to myeloproliferative diseases and 11 with reactive thrombocytosis. None of the patients with reactive thrombocytosis had thrombotic or hemorrhagic complications, but thrombosis was noted in seven patients and bleeding in two patients with thrombocythemia. Nineteen were asymptomatic. In patients with thrombosis, bleeding time, platelet glass retention, and clot retraction were normal, but evidence of platelet hyperaggregability was present in all but one. Serial studies on six patients revealed a close association between platelet hyperaggregability and ischemic attacks. Neither patient with bleeding complications had evidence of platelet hyperaggregability, although poor platelet function was found in one. Platelet function in asymptomatic patients can be classified as hyperactive, hypoactive, or normal.

Associations of medical status and physical fitness with periodontal disease

To determine the possible associations of medical status and physical fitness with periodontal disease, a cross-sectional study was conducted. The subjects were 517 males and 113 females aged 23 to 83 years who participated in a multiphasic health test at the Aichi Prefectural Center of Health Care, Japan, from 1992 to 1997. Their periodontal status was assessed by means of the CPITN scoring system. To assess the strength of associations between the examined factors and the score, odds ratios were computed using ordinal logistic models. Conventional risk factors such as old age, smoking habits, and higher fasting plasma glucose and simplified debris index increased the risk of periodontal disease. Hypertension, hematuria, leucocytosis or thrombocytosis, positive C-reactive protein and higher serum alkaline phosphatase were positively associated with the score, whereas higher serum high-density lipoprotein cholesterol was related to a lower risk. Poor physical fitness affecting aerobic capacity, foot balance and reaction was associated with a higher CPITN score. These associations were independent of the conventional risk factors. Although these new potential risk factors should be further investigated for their causal relationship, our findings suggested a close relationship of oral health to medical status and physical fitness.

The incidence of thrombotic and hemorrhagic disorders in association with extreme thrombocytosis: an analysis of 129 cases

We have presented a retrospective study of 129 patients with platelet counts of 1,000 X 10(9)/L or more--72 with myeloproliferative disorders (MPD), and 57 with reactive thrombocytosis (RT)--in an effort to determine the incidence of thrombohemorrhagic complications. Thrombotic disorders occurred with approximately equal frequency in the two groups, being found in three patients (4%) with MPD and three (5%) with RT when the platelet count was over 1,000 X 10(9)/L and in 11% of the patients in each group when the platelet count was less than 1,000 X 10(9)/L. In contrast, bleeding manifestations were more common in MPD, where 36% of patients were affected on one or more occasions versus only 4% of those with RT. However, bleeding was generally not severe, with only six patients requiring transfusions, and three of these patients had been receiving aspirin or corticosteroids when they developed severe gastrointestinal bleeding.

Prognostic value of thrombocytosis in renal cell carcinoma

PURPOSE

We correlated platelet count to renal tumor characteristics, and evaluated the potential prognostic value of thrombocytosis in localized and metastatic tumors.

MATERIALS AND METHODS

A total of 804 patients operated on for a renal tumor in 2 French centers were included in this study. In all cases TNM stage, Fuhrman grade, tumor size, nodal invasion, ECOG score, histological subtype and platelet count were recorded. Survival estimates were compared with the Kaplan-Meier method and multivariate analysis was performed using a Cox model.

RESULTS

There were 538 (66.9%) males and 266 (33%) females (ratio 2.02) in the patient group. Median age was 62 years. T stages were T1, T2, T3 and T4 in 284 (35.3%), 116 (14.4%), 387 (48.1%) and 17 (2.1%), respectively. There were 112 (13.9%) and 126 (15.7%) patients with nodal and metastatic invasion, respectively. Platelet count was strongly correlated with T stage (p < 0.001), Fuhrman grade (p < 0.001), tumor size (p < 0.001), nodal invasion (p < 0.001) and the presence of distant metastasis (p = 0.01). In univariate analysis all studied factors were significantly predictive of survival (p = 0.0001). Thrombocytosis had an impact on prognosis in localized (p < 0.001) and metastatic (p = 0.003) disease. Several factors were retained in multivariate analysis, namely TNM stage, Fuhrman grade, tumor size, ECOG score and platelet count. In cases with a platelet count of less than 450,000/mm3, the 5-year survival rate was 70%, compared to 38% when the platelet count was 450,000/mm3 or greater.

CONCLUSIONS

Platelet count appears to be an independent prognostic factor in renal cell carcinoma. It reflects a cascade of biological events correlated with tumor aggressiveness. This observation opens new perspectives for exploring carcinogenesis mechanisms and tumor progression in renal cell carcinoma.

Prevalence of retinopathy in patients with anemia or thrombocytopenia

BACKGROUND AND OBJECTIVES

Fundus lesions can be the accompanying symptom in many hematological diseases. In cases of anemia or thrombocytopenia, the exact mechanism leading to fundus abnormalities is not completely understood. The aim of this study was to calculate the prevalence of fundus lesions in anemic and thrombocytopenic patients, and define the risk factors for retinopathy.

DESIGN AND METHODS

This cross-sectional study involved 226 patients with anemia and/or thrombocytopenia and a control group of 47 age-matched subjects. The studied variables were age, gender, hemoglobin levels, mean cell volume (MCV), red cell distribution width coefficient variation (RDW-CV), the type of onset of anemia, platelet counts, mean platelet volume (MPV), platelet distribution width (PDW), the platelet-large-cell ratio (P-LCR), prothrombin time (PT) and partial thromboplastin time (PTT).

RESULTS

Retinopathy was observed in 28.3% of the patients as a whole, the presence of fundus lesions being closely associated with severe anemia (Hb < 8 g/dL) and severe thrombocytopenia (PLT < 50 x 109/L). Among the patients with concomitant anemia and thrombocytopenia, the incidence of retinopathy was 38%. Age, low hemoglobin levels, platelet counts, RDW-CV, and increased MCV, MPV and P-LCR were all significantly associated with the presence of fundus lesions at univariate analysis.

INTERPRETATION AND CONCLUSIONS

Retinopathy is a frequent finding in anemic and thrombocytopenic patients, although it is often not significant clinically. As retinal hemorrhages were found in all of the patients with concomitant severe anemia and thrombocytopenia, it is recommended that all such patients undergo routine fundus examinations.

Preoperative lipid-control with simvastatin reduces the risk of postoperative thrombocytosis and thrombotic complications following CABG

OBJECTIVE

It has earlier been suggested that postoperative thrombocytosis frequently occur after coronary artery bypass grafting (CABG) and may be linked to lipid disturbances. A prospective randomized study was undertaken to evaluate if preoperative lipid-control, using HMG-CoA-reductase inhibitor (Zocor), simvastatin, reduces the risk of postoperative thrombocytosis.

METHODS

Seventy-seven patients with symptomatic coronary artery disease and hypercholesterolemia (total cholesterol > or =6.2 mmol/l), planned for CABG where randomly assigned to; undergo CABG without preoperation lipid control (group I, n = 37) or undergo simvastatin-treatment (20 mg daily) to control their lipids (4 weeks) prior to CABG (group II, n = 40).

RESULTS

Patient characteristics and operation data did not differ between the groups. Serum-cholesterol, cholesterol/HDL-cholesterol, LDL-cholesterol, Apolipoprotein A1 and Plasminogen were all significantly higher in group I patients compared with group II just prior to surgery. Other laboratory parameters did not differ.

RESULTS

In group II, total cholesterol and cholesterol/HDL-cholesterol quota were significantly lowered by simvaststin (-2 and -29%, respectively). Postoperative thrombocytosis (platelet counts > or =400000/microl) occurred significantly more frequently in group I 81% (30/37) compared with 3% (1/40) in group II, P<0.0001. Myocardial infarction after the 7th postoperative day was more often diagnosed in group I, 14 vs. 0% in group II. Postoperative transient renal failure occurred also more frequently in group I, 24% compared with 8% in group II. Other postoperative complications and laboratory data did not differ.

CONCLUSIONS

This study once again underlines the importance of lipid control using HMG-CoA-reductase inhibitors (e.g. Zocor) in patients with established coronary artery disease. For the first time it is shown that lipid-control with simvastatin prior to CABG reduces the risk of postoperative thrombocytosis, thus lowers the risk for thrombotic complications.

Uncontrolled thrombocytosis in chronic myeloproliferative disorders

A retrospective study was performed to examine the natural course of uncontrolled thrombocytosis associated with chronic myeloproliferative disorders. Thirty-eight patients with polycythaemia rubra vera (PV), myelofibrosis/myeloid metaplasia (MM), chronic myelogenous leukaemia (CML) or essential thrombocythaemia (ET) had platelet counts greater than 1000 X 10(9)/1 and were followed closely for a total of 246 patient years. Eleven of the patients experienced haemorrhagic episodes. Bleeding was twice as frequent in patients over 59 years old as in those younger and no bleeding occurred in those less than 51 years of age. There was no correlation between frequency of bleeding and extent of thrombocytosis. Bleeding events occurred concurrently with use of anti-inflammatory agents in 32% of episodes. The gastrointestinal tract was the most frequent site. Documented thrombotic events occurred in three patients, two of whom had PV with haematocrits greater than 53%. This study suggests that the thrombocytosis of myeloproliferative processes may pose a less serious threat than originally thought and that aggressive lowering of the platelet count may not be indicated in all cases.

Carotid artery thrombus associated with severe iron-deficiency anemia and thrombocytosis

BACKGROUND

Thrombus within the carotid artery usually occurs in vessels with severe atherosclerotic disease and may embolize to cause transient ischemic attacks and cerebral infarctions. The risk factors for carotid artery thrombus formation in the absence of atherosclerosis are not well characterized. A case series is presented that suggests an association of carotid artery thrombus with severe iron-deficiency anemia and thrombocytosis.

CASE DESCRIPTIONS

We describe three women with severe iron-deficiency anemia and thrombocytosis secondary to menorrhagia who developed carotid artery thrombi. Thrombi were detected radiographically. The patients were treated with anticoagulation and antiplatelet therapy. In two patients, follow-up neuroimaging 10 to 14 days later demonstrated resolution of the thrombus and no identifiable vascular disease.

CONCLUSIONS

Severe iron-deficiency anemia with thrombocytosis may be a risk factor for carotid artery thrombus formation. Medical management with anticoagulation and antiplatelet therapy is a reasonable approach for these patients while the thrombus resolves.

Effects of a prolonged vitamin E deficiency in the rat

Rats fed a vitamin E-deficient diet containing 10% "stripped" corn oil had reduced growth rate and elevated platelet count by 12 weeks of age, and a normocytic anemia with elevated reticulocytes by 16 weeks of age. After 5 months, rats became emaciated and developed kyphoscoliosis. Some rats developed skin ulcers and tremors, and mortality was high. Neuromuscular lesions included a chronic necrotizing myopathy and localized axonal dystrophy. There was also a selective activation of lysosomes in the central nervous system microcirculation. Liver ascorbic acid of deficient rats was the same as in those receiving vitamin E. Urinary excretion of p-hydroxyphenylpyruvate after a tyrosine load was also the same in deficient and control rats. It was concluded that neither vitamin C synthesis or utilization was affected the E-deficient rats.