Association of vena cava filters and catheter-directed thrombolysis for deep vein thrombosis with hospital readmissions

BACKGROUND

Acute deep vein thrombosis (DVT) affects >350,000 patients each year in the United States. Contemporary rehospitalization rates and predictors of acute DVT have not been well-characterized. We aimed to evaluate the all-cause 30-day readmission rate and its association with catheter-directed thrombolysis and vena cava filters in patients with proximal and caval DVT.

METHODS

Patients with an index hospitalization for acute proximal lower extremity DVT were evaluated for unplanned readmission rates at 30 days using the Nationwide Readmission Database from 2016 to 2017. We used Cox proportional hazard model to determine the predictors of 30-day readmissions and their association with inferior vena cava (IVC) filter and CDT use.

RESULTS

We identified 58,306 adult patients with an index hospitalization for acute proximal DVT. The unplanned 30-day rehospitalization rate was 14.7% (95% confidence interval [CI], 14.5-15.0%). There were 4995 patients (10.0%) who underwent CDT and 6085 (12.2%) who underwent IVC filter placement. In multivariable analysis, only CDT was associated with a lower hazard for rehospitalization (hazard ratio [HR], 0.77; 95% CI, 0.71-0.84; P < .001), whereas IVC filter placement (HR, 1.26; 95% CI, 1.19-1.34; P < .001), Charlson Comorbidity Index of >3 (HR, 1.47; 95% CI, 1.38-1.56; P < .001), malignancy (HR, 1.45; 95% CI, 1.34-1.57; P < .001), and length of stay >5 days (HR, 1.39; 95% CI, 1.33-1.46; P < .001), and acute kidney injury (HR, 1.18; 95% CI, 1.11-1.25; P < .001) were associated with higher readmission rates.

CONCLUSIONS

The 30-day unplanned rehospitalization rate continues to be high in patients with acute proximal DVT. CDT was associated with lower rehospitalization rates, whereas IVC filter placement was associated with increased rehospitalization rates.

Twelve-month end point results from the evaluation of the Zilver Vena venous stent in the treatment of symptomatic iliofemoral venous outflow obstruction (VIVO clinical study)

BACKGROUND

In the present study, we evaluated the safety and effectiveness of the Zilver Vena venous stent in the treatment of patients with symptomatic iliofemoral outflow obstruction.

METHODS

The VIVO clinical study was a prospective, nonrandomized, multicenter study that enrolled patients with symptomatic obstruction of one iliofemoral venous segment. Included were patients with Clinical, Etiological, Anatomical, Pathophysiological (CEAP) clinical classification of ≥3 or a Venous Clinical Severity Score (VCSS) pain score of ≥2. All patients received a self-expanding venous stent (Zilver Vena venous stent; Cook Ireland Ltd, Limerick, Ireland). The primary safety end point was 30-day freedom from major adverse events. The primary effectiveness end point was the 12-month rate of primary quantitative patency by venography as determined by the core laboratory. The secondary end point was the change in the VCSS from baseline to 1 and 12 months. Additional measures included freedom from clinically driven reintervention; change in the CEAP C classification, Venous Disability Score (VDS), and Chronic Venous Disease Quality of Life Questionnaire (CIVIQ) scores from baseline to 12 months; and stent durability measures.

RESULTS

Between December 2013 and October 2016, 243 patients (70% female; mean age, 53 ± 15 years; 67.5% with current or previous deep vein thrombosis) were enrolled at 30 institutions. Iliac vein compression by the iliac artery (n = 191; 78.6%) was the primary indication for stent placement. The mean lesion length was 98.6 ± 69.8 mm. The 30-day freedom from major adverse events rate was 96.7%, greater than the literature-defined performance goal of 87% (95% confidence interval [CI], 93.5%-98.6%; P < .0001). The 12-month primary quantitative patency rate was 89.9%, greater than the literature-defined performance goal of 76% (95% CI, 85.1%-93.4%; P < .0001). The change in the VCSS from baseline was -3.0 (95% CI, -3.5 to -2.6; P < .0001) at 1 month and -4.2 (95% CI, -4.7 to -3.7; P < .0001) at 12 months, demonstrating clinical improvement. Similarly, significantly (P < .0001) fewer symptoms over time (from preprocedure through 12 months) were measured using the clinical measures of VDS, CEAP C classification, and CIVIQ. The 12-month rate of freedom from clinically driven reintervention was 95.8% ± 1.3%. Through 12 months, no stent fractures and one clinical migration (Clinical Events Committee adjudicated the latter as technique-related due to device undersizing at placement) had occurred.

CONCLUSIONS

The 12-month results of the VIVO study have demonstrated the safety and effectiveness of the Zilver Vena venous stent for the treatment of symptomatic iliofemoral venous outflow obstruction, including clinical symptom improvement compared with baseline.

GREAT SAPHENOUS VEIN OCCLUSION RATES AFTER COMBINED TREATMENT WITH LASER AND FOAM SCLEROTHERAPY

BACKGROUND

Endovenous Laser Ablation (EVLA) and foam sclerotherapy are effective and safe treatments for chronic venous disease (CVD) with great saphenous vein (GSV) reflux. We report our experience combining both strategies as a merged approach to treat GSV incompetence to potentiate both methods' superiority and benefits. We aimed to determine the effectiveness of this treatment strategy.

METHODS

246 limbs with great saphenous vein incompetence (C2-C6) treated with EVLA and foam sclerotherapy between January 2016 and December 2019 were retrospectively analyzed. Outcomes of interest were the International Union of Phlebology type of anatomic closure (primary, primary assisted, secondary and therapeutic failure), identified with ultrasound in the GSV after the procedure. Clinical and ultrasound follow-up was conducted at two weeks, 3, 6, and 12 months post-intervention. We utilized Fisher's exact test to determine the significance of the association between the type of anatomic closure and the clinical stage according to the CEAP classification.

RESULTS

67% of the treated limbs were C2-C4 and 33% C5-C6. International Union of Phlebology (IUP) primary closure was achieved in 229 limbs (93%), IUP primary assisted closure in 10 (4%), IUP secondary closure in 1 (0.4%), with therapeutic failure in 6 limbs (2%). Forty-five limbs (18%) required microthrombectomies of tributary veins due to local induration, 7 (2.8%) developed dyschromia, 4 (1.6%) had type 1 Endovenous Heat-Induced Thrombosis (E-HIT1), and one limb (0.4%) developed deep vein thrombosis (DVT), which was successfully treated with anticoagulation.

CONCLUSIONS

Our results demonstrate a high occlusion rate of incompetent GSVs with combined EVLA and foam sclerotherapy with infrequent non-serious complications and one case of subclinical isolated popliteal DVT. Combined therapy effectiveness and safety are comparable with other endovenous treatments for CVD with GSV reflux. The use of both thermal and chemical ablation combines the benefits of both techniques.

Pharmacomechanical Catheter-Directed Thrombolysis in Acute Femoral–Popliteal Deep Vein Thrombosis: Analysis from a Stratified Randomized Trial

Background and Objectives The Acute Venous Thrombosis: Thrombus Removal with Adjunctive Catheter-Directed Thrombolysis (ATTRACT) trial reported that pharmacomechanical catheter-directed thrombolysis (PCDT) did not reduce post-thrombotic syndrome (PTS), but reduced moderate-to-severe PTS and the severity of PTS symptoms. In this analysis, we examine the effect of PCDT in patients with femoral–popliteal deep vein thrombosis (DVT) (without involvement of more proximal veins).

Patients and Methods Within the ATTRACT trial, 300 patients had DVT involving the femoral vein without involvement of the common femoral or iliac veins and were randomized to receive PCDT with anticoagulation or anticoagulation alone (no PCDT). Patients were followed for 24 months.

Results From 6 to 24 months, between the PCDT versus no PCDT arms, there was: no difference in any PTS (Villalta scale ≥ 5: risk ratio [RR] = 0.97; 95% confidence interval [CI], 0.75–1.24); moderate-or-severe PTS (Villalta scale ≥ 10: RR = 0.93; 95% CI, 0.57–1.52); severity of PTS scores; or general or disease-specific quality of life (p > 0.5 for all comparisons). From baseline to both 10 and 30 days, there was no difference in improvement of leg pain or swelling between treatment arms. From baseline to 10 days, major bleeding occurred in three versus none (p = 0.06) and any bleeding occurred in eight versus two (p = 0.032) PCDT versus no PCDT patients. Over 24 months, recurrent venous thromboembolism occurred in 16 PCDT and 12 no PCDT patients (p = 0.24).

Conclusion In patients with femoral–popliteal DVT, PCDT did not improve short- or long-term efficacy outcomes, but it increased bleeding. Therefore, PCDT should not be used as initial treatment of femoral–popliteal DVT. (NCT00790335).

Effect of antiplatelet agents clopidogrel, aspirin, and cilostazol on circulating tissue factor procoagulant activity in patients with peripheral arterial disease

Tissue factor (TF) is the physiological initiating mechanism for blood coagulation. Platelets play an important role in monocyte TF expression, thrombosis and inflammation. Aspirin, clopidogrel and cilostazol, which inhibit platelet responses by different mechanisms, are widely used in patients with arterial diseases. We tested the hypothesis that platelet-inhibiting agents inhibit the levels of circulatingTF procoagulant activity (TF-PCA) in patients with peripheral arterial disease (PAD).Twenty-six patients with lower extremity PAD, average age 65.9 ± 8.4 years (mean± SEM), were studied at baseline and following sequential twoweek treatment regimens with aspirin (325 mg daily), clopidogrel (75 mg daily) or a phosphodiesterase inhibitor cilostazol (100 mg twice daily) singly, and with each possible combination of these agents. Circulating TF-PCA in whole blood, and plasma factor VIIa, prothrombin fragment F1.2, thrombin-antithrombin complexes (TAT), and P-selectin were measured. Baseline TFPCA levels in the patients were elevated (131 ± 19 U/ml) compared to control subjects (23 ± 2, p<0.0001).TF-PCA levels declined following treatment with clopidogrel alone, and with combinations of clopidogrel with aspirin or cilostazol, with the lowest levels being with the triple-drug combination. Plasma P-selectin declined in all treatment groups. No changes were noted in plasma factorVIIa, F1.2 or TAT.In conclusion, treatment of PAD patients with antiplatelet agents decreases circulatingTF, a molecule with prothrombotic and proinflammatory effects. These findings suggest an unrecognized mechanism, beyond inhibiting aggregation responses, for the efficacy of antiplatelet drugs in patients with arterial diseases.

Recommendations for the medical management of chronic venous disease: The role of Micronized Purified Flavanoid Fraction (MPFF)

Scope A systematic review of the clinical literature concerning medical management of chronic venous disease with the venoactive therapy Micronized Purified Flavonoid Fraction was conducted in addition to an investigation of the hemodynamics and mechanism of chronic venous disease. Methods The systematic review of the literature focused on the use of Micronized Purified Flavonoid Fraction (diosmin) which has recently become available in the US, in the management of chronic venous disease. The primary goal was to assess the level of evidence of the role of Micronized Purified Flavonoid Fraction in the healing of ulcers, and secondarily on the improvement of the symptoms of chronic venous disease such as edema. An initial search of Medline, Cochrane Database for Systematic Reviews and Google Scholar databases was conducted. The references of articles obtained in the primary search, including a Cochrane review of phlebotonics for venous insufficiency, were reviewed for additional studies. Studies were included if patients had a diagnosis of chronic venous disease documented with Doppler and Impedance Plethysmography. Studies excluded were those that had patients with arterial insufficiency (Ankle Brachial Index < .6), comorbidity of diabetes, obesity, rheumatological diseases, or if other causes of edema were present (congestive heart failure, renal, hepatic or lymphatic cause), or if the patient population had recent surgery or deep vein thrombosis, or had been using diuretics (in studies of edema). Other elements of the study design were to note specifically the type of compression therapy used in conjunction with Micronized Purified Flavonoid Fraction. Results The literature review yielded 250 abstracts, 65 of which met criteria for further review and 10 papers were selected for consideration in the systematic review. Conclusion In summary, the general level of evidence supports the recommendation that the use of medical therapy with Micronized Purified Flavonoid Fraction has beneficial outcomes without serious adverse events. In the United States, diosmiplex is the only available prescription formulation of Micronized Purified Flavonoid Fraction. It is derived from the rinds of oranges and is categorized as a medical food and not as a drug; and may be a particularly attractive therapy for many chronic venous disease patients because of its favorable safety profile. The Working Group for chronic venous disease concurs with previous guidance by the International European Society for Vascular Surgery in 2015 which recommended the use of Micronized Purified Flavonoid Fraction for the healing of venous ulcers, alone and adjunctive to compression therapy, and for the reduction in symptoms of chronic venous disease such as edema.

Pathogenesis of venous ulcer

The underlying pathophysiology of venous ulceration is venous hypertension, which initiates a complex cascade of cellular humeral events that are then magnified by genetic factors. Hemodynamic abnormalities are features of primary and secondary chronic venous diseases that lead to disease progression. Through a sequence of events, some patients develop venous leg ulcers, if the process is not interrupted. The exact science of the pathophysiology of the progression of chronic venous disease to venous leg ulcers is still in its infancy, but the framework for future study has been established.

Divergent effects of Tlr9 deletion in experimental late venous thrombosis resolution and vein wall injury

Deep-vein thrombosis (DVT) resolves via a sterile inflammatory response. Defining the inflammatory response of DVT may allow for new therapies that do not involve anticoagulation. Previously, we have shown that Toll-like receptor 9 (Tlr9) gene deleted mice had impaired venous thrombosis (VT) resolution. Here, we further characterise the role of Tlr9 signalling and sterile inflammation in chronic VT and vein wall responses. First, we found a human precedent exists with Tlr9+ cells present in chronic post thrombotic intraluminal tissue. Second, in a stasis VT mouse model, endogenous danger signal mediators of uric acid, HMGB-1, and neutrophil extracellular traps marker of citrullinated histone-3 (and extracellular DNA) were greater in Tlr9-/- thrombi as compared with wild-type (WT), corresponding with larger VT at 8 and 21 days. Fewer M1 type (CCR2+) monocyte/macrophages (MØ) were present in Tlr9-/- thrombi than WT controls at 8 days, suggesting an impaired inflammatory cell influx. Using bone marrow-derived monocyte (BMMØ) cell culture, we found decreased fibrinolytic gene expression with exposure to several endogenous danger signals. Next, adoptive transfer of cultured Tlr9+/+ BMMØ to Tlr9-/- mice normalised VT resolution at 8 days. Lastly, although the VT size was larger at 21 days in Tlr9-/- mice and correlated with decreased endothelial antigen markers, no difference in fibrosis was found. These data suggest that Tlr9 signalling in MØ is critical for later VT resolution, is associated with necrosis clearance, but does not affect later vein wall fibrosis. These findings provide insight into the Tlr9 MØ mechanisms of sterile inflammation in this disease process.

Medical management of patients with peripheral arterial disease

Peripheral arterial disease (PAD) is one of the most frequent manifestations of atherosclerosis and is associated with atherosclerosis in the coronary and carotid arteries, leading to a highly increased incidence of cardiovascular events. Major risk factors of PAD are similar to those that lead to atherosclerosis in other vascular beds. However, there are differences in the power of individual risk factors in the different vascular territories. Cigarette smoking and diabetes mellitus represent the greatest risks of PAD. For prevention of the progression of PAD and accompanying cardiovascular events similar preventative measures are used as in coronary artery disease (CAD). However, recent data indicate that there are some differences in the efficacy of drugs used in the prevention of atherothrombotic events in PAD. Antiplatelet treatment is indicated in virtually all patients with PAD. In spite of the absence of hard evidence- based data on the long term efficacy of aspirin, it is still considered as a first line treatment and clopidogrel as an effective alternative. The new antiplatelet drugs ticagrelol and prasugrel also represent promising options for treatment of PAD. Statin therapy is indicated to achieve the target low density lipoprotein cholesterol level of ≤2.5 mmol/L (100 mg/dL) and there is emerging evidence that lower levels are more effective. Statins may also improve walking capacity. Antihypertensive treatment is indicated to achieve the goal blood pressure (<140/90 mmHg). All classes of antihypertensive drugs including beta-blockers are acceptable for treatment of hypertension in patients with PAD. Diabetic patients with PAD should reduce their glycosylated haemoglobin to ≤7%. As PAD patients represent the group with the highest risk of atherothrombotic events, these patients need the most intensive treatment and elimination of risk factors of atherosclerosis. These measures should be as comprehensive as those in patients with established coronary and cerebrovascular disease.

Deletion of cysteine-cysteine receptor 7 promotes fibrotic injury in experimental post-thrombotic vein wall remodeling

OBJECTIVE

Deep vein thrombosis (VT) can result in vein wall injury, which clinically manifests as post-thrombotic syndrome. Postinjury fibrosis may be modulated in part through cellular cysteine-cysteine receptor 7 (CCR7)-mediated events. We tested the hypothesis that late vein wall fibrotic remodeling is dependent on CCR7.

APPROACH AND RESULTS

CCR7(-/-) and C57BL/6 wild-type mice had inferior vena cava VT induced by nonstasis or stasis mechanisms. In both models, VT size was largest at day 1 and trended down by day 21, and CCR7(+) cells peaked at day 8 in wild-type mice. No significant differences in VT resolution were found in CCR7(-/-) as compared with wild type in either model. In the nonstasis VT model, vein wall changes consistent with fibrotic injury were evidenced by significant increases in collagen I, III, matrix metalloproteinase 2, and transforming growth factor-β gene expression, increases in α-smooth muscle actin and fibroblast specific protein-1 antigen, and total collagen at 8 days. Correspondingly, SM22α and fibroblast specific protein-1, but not DDR2(+) cells, were increased at 8 days. Early wild-type thrombus exposure inhibited profibrotic gene expression in CCR7(-/-) in ex vivo vein wall culture. Bone marrow chimera experiments further showed that circulating CCR7(+) leukocytes partially rescued midterm profibrotic changes in CCR7(-/-) mice. In human histological sections of chronic thrombosed femoral veins, CCR7(+) cells were present in the fibrotic areas.

CONCLUSIONS

Post-thrombotic vein wall remodeling is impaired in CCR7(-/-) mice, with a profibrotic phenotype, is dependent on the thrombotic mechanism, and is mediated by circulating CCR7(+) cells. Unlike other postinjury fibrotic responses, CCR7(+) signaling may be important for positive vein wall remodeling after VT.

Subintimal Angioplasty for Advanced Lower Extremity Ischemia due to TASC II C and D Lesions of the Superficial Femoral Artery

Objective: Subintimal angioplasty (SA) has evolved into a viable revascularization procedure for complex lower extremity lesions. Although patency rates are lower than those for autogenous bypass, limb salvage rates are comparable. This study reviewed the 8-year experience of SA in a single center.

Methods: Records of patients undergoing SA were reviewed. Clinical presentation and noninvasive exams were used to classify patients. Lesions were categorized by TransAtlantic InterSociety Consensus (TASC) II guidelines. Outcomes included technical success, patency, amputation-free survival, and limb salvage.

Results: 120 patients with TASC II C/D lesions underwent SA. Technical success was 91%. Primary patency at 6 and 12 months was 90% and 73%. Secondary patency at 6 and 12 months was 94% and 85%. One-year amputation-free survival was 90%. One-year limb salvage was 98%.

Conclusions: SA for TASC C/D lesions is a safe procedure and may be considered an alternative to bypass, especially in high-risk patients.

Confusion of Peripheral Arterial Doppler Waveform Terminology

Characterization of peripheral arterial waveforms is basic to the diagnosis of vascular disease. Surveys indicate inconsistent application of traditional waveform descriptors. This study reviews literature to identify areas of confusion. Publications were reviewed to determine whether triphasic, biphasic, and monophasic terms were defined; if biphasic was linked with diastolic flow reversal; whether pandiastolic flow was associated with biphasic or monophasic terminology; and whether waveform illustrations had a zero baseline. Ninety-four publications were reviewed. Triphasic and monophasic were defined in 81%, biphasic in 48%. Biphasic was classified with flow reversal in 38%. Pandiastolic flow was not addressed in 57% but associated with monophasic in 47% and biphasic in 5%. Twenty-one percent of the publications had an illustration without a zero-flow baseline. This review suggests a lack of consensus when classifying arterial blood flow with traditional waveform descriptors. Waveform characterization inconsistencies are undermining comprehension of Doppler principles and may lead to inappropriate testing. A multisocietal consensus panel should accept responsibility for resolving this issue.

Local gene transfer and expression following intramuscular administration of FGF-1 plasmid DNA in patients with critical limb ischemia

NV1FGF is an expression plasmid encoding sp.FGF-1(21-154) currently under investigation for therapeutic angiogenesis in clinical trials. NV1FGF plasmid distribution and transgene expression following intramuscular (IM) injection in patients is unknown. The study involved six patients with chronic critical limb ischemia (CLI) planned to undergo amputation. A total dose of 0.5, 2, or 4 mg NV1FGF was administered as eight IM injections (0.006, 0.25, or 0.5 mg per injection) 3-5 days before amputation. Injected sites (30 cm(3)) were divided into equally sized smaller pieces to assess spatial distribution of NV1FGF sequences (PCR), NV1FGF mRNA (reverse transcriptase-PCR), and fibroblast growth factor-1 (FGF-1)-expressing cells (immunohistochemistry). Data indicated gene expression at all doses. The distribution area was within 5-12 cm for NV1FGF sequences containing the expression cassette, up to 5 cm for NV1FGF mRNA, and up to 3 cm for FGF-1-expressing myofibers. All FGF receptors were detected indicating robust potential for bioactivity after NV1FGF gene transfer. Circulating levels of NV1FGF sequences were shown to decrease within days after injection. Data support demonstration of plasmid-mediated gene transfer and expression in muscles from patients with CLI. FGF-1 expression was shown to be limited to injection sites, which supports the concept of multiple-site injection for therapeutic use.

Prevention of venous thromboembolism: adherence to the 1995 American College of Chest Physicians consensus guidelines for surgical patients

BACKGROUND

The American College of Chest Physicians addressed the dilemma of identifying optimal therapy for venous thromboembolism (VTE) prophylaxis and published their Fourth Consensus Conference on Antithrombotic Therapy in 1995, with recommendations for prophylactic therapy. Despite these recommendations, appropriate VTE prophylactic therapy is underused.

OBJECTIVES

To examine routine practices in the prevention of VTE in high-risk surgical patients and to determine the extent of adoption of grade A prophylactic therapies as recommended by the American College of Chest Physicians.

METHODS

Retrospective medical record review in 10 teaching or community-based hospitals located in the United States. Medical charts of 1907 patients were randomly selected for review from the population of patients who underwent high-risk major abdominal surgery, total hip replacement, hip fracture repair, or total knee replacement between January 1, 1996, and February 28, 1997.

RESULTS

Of 1907 patients, VTE prophylaxis was used in 89.3%; use was 93.7% in each of the 3 orthopedic surgery groups and 75.2% in the high-risk major abdominal surgery group. The percentage of patients receiving grade A therapy was highest in the hip replacement group (84.3%) vs. the other groups (knee replacement, 75.9%; hip fracture repair, 45.2%; abdominal surgery, 50.3%).

CONCLUSIONS

The use of grade A prophylaxis was related to the type of surgery, with the highest use seen in total hip replacement and the lowest in hip fracture repair. One in 4 patients who underwent high-risk major abdominal surgeries failed to receive any form of VTE prophylaxis. Publication of consensus statements alone may be insufficient to ensure the incorporation of important new clinical information into routine practice.

Antiplatelet therapy in the prevention of ischemic vascular events: literature review and evidence-based guidelines for drug selection

BACKGROUND

New antiplatelet drugs are being developed and many clinical trials evaluating the benefits of antiplatelet drugs for the secondary prevention of ischemic events in patients with atherosclerotic vascular disease have been performed.

HYPOTHESIS

An updated systematic review and evidence-based guidelines for the appropriate selection of antiplatelet drugs may be beneficial to physicians and healthcare organizations attempting to create or update current clinical practice guidelines or clinical pathways aimed at caring for these patients.

METHODS

(1) A systematic review of the recent literature on the relative efficacy and safety of aspirin, ticlopidine, and clopidogrel was undertaken; (2) an evidence-based, expert panel approach using a modified Delphi technique to create explicit guidelines for prescribing antiplatelet therapy was instituted; and (3) the recommendations of an expert panel were summarized.

RESULTS

Consensus guidelines were developed for the utilization of aspirin, ticlopidine, or clopidogrel for the prevention of ischemic events in patients with manifestations of atherosclerotic vascular disease (prior myocardial infarction, prior ischemic stroke, or established peripheral arterial disease) who are at increased risk for recurrent ischemic events. Based on efficacy and safety, clopidogrel was recommended as the drug of choice for patients with established peripheral arterial disease; aspirin or clopidogrel should be considered in patients with prior myocardial infarction (with clopidogrel favored for patients who have had a recurrent event while on aspirin or in whom aspirin is contraindicated); aspirin or clopidogrel should be considered as first-line treatment in patients with prior ischemic (nonhemorrhagic) stroke--however, clopidogrel is the favored drug in patients in whom other antiplatelet drugs are either contraindicated or who have had recurrent events while on therapy.

CONCLUSIONS

Myocardial infarction, ischemic stroke, and peripheral arterial disease are all clinical manifestations of the same underlying disease process (atherosclerosis), with thrombus formation on the disrupted atherosclerotic plaque (atherothrombosis) being a common precipitating factor of ischemic events in patients suffering from these disorders. An evidence-based approach was used to develop a practice guideline, based on available published evidence, for the appropriate utilization of antiplatelet agents (aspirin, ticlopidine, or clopidogrel). These guidelines may be of use to multidisciplinary teams wishing to create or update clinical guidelines or clinical pathways which address the care of patients with atherosclerotic vascular disease. New antiplatelet agents such as clopidogrel may be more effective and associated with lower risk of selected adverse effects (such as gastrointestinal distress, gastrointestinal hemorrhage, and neutropenia) than those previously used to prevent thrombus formation in the setting of atherosclerotic arterial disease. Combination antiplatelet therapy is being evaluated as an option for those patients who experience recurrent events on a single antiplatelet agent.

A noninvasive screening test to detect "critical" deep venous reflux

PURPOSE

The venous filling index (VFI) was introduced as a noninvasive measure of venous valvular reflux. Because it is quantitative, identifying increasingly severe reflux should be possible. The purpose of this study is to evaluate the sensitivity and predictive value of the VFI as a predictor of phlebographically demonstrated "critical" venous reflux.

METHODS

Thirty-one limbs with suspected venous insufficiency underwent both descending phlebography and air plethysmography. Nine limbs had deep venous reflux ending above the knee on descending phlebography (group 1), and 22 limbs had "critical" deep reflux to the below-knee level (group 2). The VFI, ejection fraction, and residual volume fraction were calculated, and a tourniquet was used to distinguish superficial from deep venous reflux.

RESULTS

Three of six group 2 limbs with a VFI less than 7 had obliteration of their iliac veins. Tourniquet application improved the VFI in 13 limbs, all of which showed either phlebographic or venous duplex evidence of greater saphenous incompetence.

CONCLUSIONS

A VFI greater than 7 showed a 73% sensitivity and 100% positive predictive value of identifying "critical venous reflux." The VFI may underestimate the degree of reflux in patients with proximal venous obstruction. Improvement of venous hemodynamics with tourniquet application suggests that venous reflux might be improved in some patients by correcting superficial venous insufficiency.

High-dose, brief intravenous streptokinase early in acute myocardial infarction

An acute thrombus at the proximal border of a high-grade atherosclerotic obstruction is the usual cause of myocardial infarction. Although intracoronary thrombolysis is potentially an exciting new therapy for reducing the extent of myocardial infarction by lysing coronary clot, a number of major difficulties limit its widespread application. It is a complex procedure requiring intracoronary visualization and infusion within a few hours of onset of symptoms. Since intravenous streptokinase could be widely applied if effective, we and others have wondered whether high-dose, brief-duration intravenous streptokinase infusion given early in myocardial infarction would lyse coronary clots without bleeding. To date we have treated 13 patients within 6 hours of onset of symptoms and with ECG and angiographic evidence of typical myocardial infarction caused by coronary clot. Clot lysis and angiographically proved coronary reperfusion were achieved in 6 patients within 1 hour of starting a systemic intravenous infusion of 850,000 IU of streptokinase. Schroeder et al., in Berlin, West Germany, achieved angiographically proved coronary reperfusion in 11 of 21 patients with acute myocardial infarction following a 30-minute intravenous streptokinase infusion of 500,000 IU. Neuhaus et al., in Göttinen, West Germany, achieved angiographically proved coronary reperfusion in 24 of 39 similar patients within 48 minutes by intravenous infusion of 1,700,000 IU of streptokinase. In these three studies, no serious bleeding occured; left ventricular function was improved in patients who achieved coronary reperfusion. We conclude that rapid intracoronary clot lysis and coronary reperfusion can be achieved early in myocardial infarction by brief-duration systemic intravenous infusion of high-dose streptokinase without a high incidence of serious bleeding.