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S R Kahn

Publications and source records attributed to S R Kahn.

At least 19 recordsLinked to original sources
PubMed2003

Effect of graduated elastic compression stockings on leg symptoms and signs during exercise in patients with deep venous thrombosis: a randomized cross-over trial.

Graduated elastic compression stockings (ECS) are often prescribed after deep venous thrombosis (DVT) to alleviate acute symptoms and to prevent and treat post-thrombotic syndrome (PTS). In patients with DVT, leg symptoms tend to worsen with exercise. The effects of ECS use during exercise have not been studied. Objectives were to determine whether ECS improve symptoms and signs and increase exercise capacity when worn during treadmill exercise by patients with prior DVT, with or without PTS. The methods employed a randomized cross-over trial. We recruited subjects who had a first episode of unilateral DVT at least 1 year earlier and categorized them as having, or not having, the PTS using a validated scale. Subjects underwent two identical treadmill exercise sessions at least 1 week apart, and were randomly assigned to wear knee-length 30 mmHg ECS on the affected leg during one of the two sessions. Venous symptoms, leg volume, leg circumference and calf muscle flexibility were measured in the affected leg before and after both exercise sessions. Subjects achieved similar percentage maximum predicted heart rates during both sessions. Comparing the ECS to no ECS session, there were no significant differences in treadmill time (21.2 vs. 21.2 min, P = 0.94), gain in leg volume (71 vs. 73 mL, P = 0.83), or change in soleus or gastrocnemius flexibility, whether or not PTS was present. Symptoms in general worsened slightly with exercise regardless of whether or not ECS were worn and did not differ according to PTS status. Per-subject analysis showed that use of ECS resulted in global improvement of symptoms in 25% of subjects, global worsening in 33% of subjects, and had no or inconsistent effects in 42% of subjects. Whether or not PTS was present, the use of ECS during exercise by patients with prior DVT did not improve symptoms and signs during exercise or increase exercise capacity.

Adult↗
PubMed2003

Use of elastic compression stockings after deep venous thrombosis: a comparison of practices and perceptions of thrombosis physicians and patients.

Daily long-term use of elastic compression stockings (ECS) by patients with deep venous thrombosis (DVT) may help to prevent the post-thrombotic syndrome (PTS). However, the effectiveness of ECS in clinical practice is difficult to predict, since the practices and perceptions of patients and thrombosis physicians regarding ECS have not been documented. The objectives were to survey DVT patients and thrombosis physicians on their practices and perceptions regarding use of ECS after DVT, and to evaluate whether physician perceptions are supported by patient responses. Two surveys were conducted. The first was sent to 38 Canadian thrombosis physicians. The second was administered to 80 DVT patients attending Thrombosis Clinic at one of two Canadian university-affiliated hospitals. Most physicians believed that ECS were useful in preventing PTS and in managing venous symptoms. However, there was a lack of consensus regarding the optimal timing of initiation of ECS, duration of therapy, and compression strength, and only one-third routinely prescribed ECS to asymptomatic patients to prevent PTS. Most DVT patients who were prescribed ECS purchased them, 87% wore them daily, and most reported that ECS relieved swelling and symptoms. Physicians underestimated the degree of patient compliance with ECS, but correctly identified the main reasons for non-compliance. There is a lack of consensus among thrombosis physicians regarding ECS use after DVT. Patients with DVT are willing to comply with ECS therapy and most find them to be helpful. Our findings suggest that long-term study of the optimal use of ECS after DVT is both necessary and feasible.

Adult↗
PubMed2003

Short-term natural history of isolated gastrocnemius and soleal vein thrombosis.

OBJECTIVE: Lower extremity deep vein thrombosis is often isolated to the sinusoidal veins draining the gastrocnemius and soleus muscles. The purpose of this study was to establish the incidence rate of propagation of isolated gastrocnemius and soleal vein thrombosis (IGSVT) into the deep veins of the calf and thigh. METHODS: All patients who were referred for color flow duplex ultrasonography (CFDU) for suspected deep vein thrombosis were prospectively evaluated for IGSVT. Patients with IGSVT received no systemic anticoagulation therapy and underwent serial CFDU at 5, 9, 14, 30, and 90 days after recruitment. The incidence and extent of IGSVT propagation were noted. Factors predictive of IGSVT extension were sought, including age, gender, side, symptoms, ambulatory status, and the presence of comorbid illness, including cardiac disease, cancer, hypercoagulable states, recent surgery or trauma, and previous venous disease. RESULTS: One hundred thirty-five limbs with IGSVT were studied for 3 months, and 16.3% of cases with IGSVT extended the thrombus to the level of the adjacent tibial, or peroneal, veins or higher. Only 3% of the cases with IGSVT propagated as cephalad as the popliteal vein, and 90.9% of IGSVT propagation occurred within 2 weeks of CFDU diagnosis. No IGSVT propagated to the level of the popliteal vein beyond 2 weeks from the time of CFDU diagnosis. No IGSVT extended into the deep veins of the thigh. By the end of the 3-month study period, 45.9% of thrombi had completely resolved. Only the presence of cancer was prognostic for IGSVT progression. CONCLUSION: During the 3-month study period, the short-term incidence rate of untreated IGSVT propagation to the level of the popliteal vein, even in the presence of cancer, was only 3%. Follow-up imaging to detect IGSVT propagation beyond 2 weeks from the time of diagnosis may not be necessary.

Adult↗
PubMed2001

A randomized management study of impedance plethysmography vs. contrast venography in patients with a first episode of clinically suspected deep vein thrombosis.

OBJECTIVES: In this randomized management study, we examined the safety of withholding anticoagulation on the basis of negative impedance plethysmography (IPG) compared to negative contrast venography (CV) in symptomatic patients with a first episode of clinically suspected deep vein thrombosis (DVT), and we determined the impact of the limitations of IPG or CV on their clinical utility. METHODS: Patients at a university teaching hospital presenting with a first episode of clinically suspected DVT were randomized to one of two management strategies at study entry: (1) IPG: if positive, confirmatory CV was performed. If CV was positive, anticoagulants were administered, if CV was negative, anticoagulants were held. If negative, IPG was repeated serially and if it remained negative, anticoagulants were held (n = 165). (2) CV: if positive, anticoagulants were administered, if negative, anticoagulants were held (n = 159). The negative predictive value (NPV) of IPG and CV, positive predictive value (PPV) of IPG, and the failure rate of each strategy were assessed. RESULTS: Among IPG patients, 28 of 37 with positive IPG initially or during serial testing and evaluable CV had confirmed DVT (PPV 76%; 95% confidence interval, CI [62%, 90%]). DVT was diagnosed during serial testing in 2.1% of patients with initially negative IPG who completed testing. The NPV overall of negative IPG was 98.3%. During follow-up, two patients in the IPG group (1.2%) and two patients in the CV group (1.3%) developed venous thromboembolism (VTE). Death during follow-up occurred in 11% of IPG patients compared to 6% of CV patients (P =.13) The investigation strategy failed in 25% of IPG patients and in 14% of CV patients. CONCLUSIONS: Our findings demonstrate that the two diagnostic strategies we studied are equivalent methods for ruling out DVT in patients with a first episode of suspected DVT. The PPV of IPG was too low to permit its use alone as a test to rule in DVT. Both strategies had surprisingly high failure rates.

Adult↗
PubMed2001

Is hormone replacement therapy protective for venous ulcer of the lower limbs?

PURPOSE: Estrogen has been found to increase the risk of deep vein thrombosis (DVT), which is associated with venous ulcers. A matched case-control study was therefore performed to quantify the effect of hormone replacement therapy (HRT) on the occurrence of venous ulcers of the lower limbs. METHODS: Women presenting to a participating vascular surgery department between January and December 1997 with a first open venous ulcer served as cases. Controls were sampled among women with sub-acute conditions such as skin problems, cold, headache/migraine, sore throat and mild ear infections, and were matched on referral site and age (+/- 5 years). Subjects were eligible for this study if they were postmenopausal, and excluded if they had non-palpable pedal pulse or any chronic active diseases. The study consisted of an interviewer-administered risk factor questionnaire. Conditional multivariate logistic regression analyses were performed adjusting for history of DVT and unbalanced distributions in important covariates. RESULTS: Forty-four cases and 80 matched controls were recruited. The mean age of participants was 64 years. HRT users were significantly thinner (27% with body mass index (BMI = (kg/height (m2)) > or = 27 vs. 41%, p = 0.04) and less likely to have a history of DVT (12 vs. 33%, p = 0.02) and varicose veins (VV) (52 vs. 69%, p = 0.04) than non-users. A matched univariate logistic regression analysis was performed to quantify the effect of HRT on venous ulcers and generated an odds ratio (OR) of 0.14 with 95% confidence interval of (0.04, 0.49)95%: adjusting for prior DVT resulted in an OR of 0.29 (0.09, 0.93)95%. When adjusting for BMI, history of VV, exercise, education, and smoking, the OR observed was 0.03 (0.01, 0.13)95%: further adjustment for prior DVT gave an OR estimate of 0.06 (0.01, 0.50)95%CI. CONCLUSIONS: Our study demonstrates that HRT has a protective effect on the occurrence of venous ulcers of the lower limbs. Adjusting for prior DVT moves the estimate closer to the null. DVT is a strong contraindication for HRT and therefore must be considered in order to eliminate confounding by contraindication.

Adult↗
PubMed2001

Do varicose veins affect quality of life? Results of an international population-based study.

PURPOSE: This study assessed the impact of varicose veins (VV) on quality of life (QOL) and patient-reported symptoms. METHODS: A cross-sectional population-based study was held in 166 general practices and 116 specialist clinics for venous disorders of the leg in Belgium, Canada (Quebec), France, and Italy. Study subjects included a sample of 259 reference patients without VV (CEAP class 0 or 1) and 1054 patients with VV who were classified as having VV alone (367; 34.8%), VV with edema (125; 11.9%), VV with skin changes (431; 40.9%), VV with healed ulcer (100; 9.5%), and VV with active ulcer (31; 2.9%). The main outcome measure was generic and disease-specific QOL, as measured by means of the Short-Form Health Survey-36 (SF-36) and the VEINES-QOL scale, and patient-reported symptoms as measured by the VEINES-SYM scale. RESULTS: In patients with VV, age-standardized mean SF-36 physical (PCS) and mental (MCS) scores were 45.6 and 46.1 in men and 44.2 and 43.2 in women, respectively, compared with population norms of 50. PCS scores decreased according to increasing severity of concomitant venous disease, with the lowest mean scores of 37.3 and 35.5 found in patients with VV and active ulcer. However, adjusted analyses showed no statistically significant differences between patients with VV alone and patients without VV for PCS (0.0), MCS (1.0), VEINES-QOL (-0.1), or VEINES-SYM (0.0) scores. In comparison with patients without VV, the largest differences were seen in patients with VV and edema (PCS, VEINES-QOL, and VEINES-SYM score differences of -1.8, -2.5, and -2.9, respectively) and in patients with VV and ulceration (differences of -3.3, -3.4, and -2.7, respectively). The high prevalence of major symptoms of venous disorders in patients in CEAP class 0 or 1 being treated for venous disorders (76.1% of patients had heaviness, aching legs, or swelling) might have contributed to the impairment of QOL in the reference group. CONCLUSION: Results indicate that impairment in physical QOL in patients with VV is associated with concomitant venous disease, rather than the presence of VV per se. Findings concerning QOL in patients with VV can only be reliably interpreted when concomitant venous disease is taken into account. In patients with VV alone, the objectives of cosmetic improvement and the improvement of QOL should be considered separately.

Activities of Daily Living↗
PubMed2001

Missed opportunities for prevention of venous thromboembolism: an evaluation of the use of thromboprophylaxis guidelines.

OBJECTIVES: To identify and characterize cases of potentially preventable venous thromboembolism (VTE): cases for which thromboprophylaxis was indicated, according to the American College of Chest Physicians (ACCP) consensus guidelines for VTE prevention, yet was administered inadequately. DESIGN: A historical cohort study to examine all cases of deep vein thrombosis and pulmonary embolism from 1996 to 1997 at a large teaching hospital. Of these, we determined the proportion that was potentially preventable. We examined the reasons for inadequacy of prophylaxis and the setting in which preventable VTE occurred. RESULTS: Of 253 objectively diagnosed cases of VTE in 245 patients, 44 cases (17.4%) were considered potentially preventable. This represented two thirds of all VTE cases for which thromboprophylaxis had been indicated (n = 65). Of preventable cases, the most frequent reason for inadequacy of prophylaxis was omission of prophylaxis (47.7%), followed by inadequate duration of prophylaxis (22.7%), and by incorrect type of prophylaxis (20.5%). Surgical and medical indications for thromboprophylaxis that were common among preventable cases included nonorthopedic surgery, admission to hospital for pneumonia, and stroke with lower limb paralysis. Underlying risk factors for VTE that were common among preventable cases included recent immobility, active cancer, and obesity. CONCLUSIONS: One of six cases of all VTE and two of three cases of VTE for which thromboprophylaxis had been indicated could potentially have been prevented had physicians followed the recommended ACCP guidelines. Inadequacy of prophylaxis was most often caused by omission of prophylaxis. Missed opportunities for prevention occurred most commonly in the settings of nonorthopedic surgery, pneumonia, and stroke.

Aged↗
PubMed2000

Program description: a hospitalist-run, medical short-stay unit in a teaching hospital.

A hospitalist-run medical short-stay unit (MSSU) was created at a university-affiliated teaching hospital in Montreal in 1989. Its primary aim was to provide efficient and high-quality care to patients requiring a brief stay in hospital for short-lived medical conditions. After evaluation in the emergency department (ED), patients judged to have acute conditions requiring a short hospital stay are admitted directly to the MSSU. Conversely, patients with more complex conditions requiring a longer stay in hospital are admitted to a clinical teaching unit (CTU). Care in the MSSU is provided by a rotating group of hospitalists. Ensuring the admission of appropriate patients during non-daytime hours was the main difficulty identified. Preliminary evaluation of the MSSU suggested that ED consultants were effective at selecting suitable patients for admission to the MSSU, because only 1 in 5 patients later required transfer to other hospital wards. The 5 most common MSSU discharge diagnoses were asthma and chronic obstructive lung disease, pneumonia, congestive heart failure, urinary tract infection and cellulitis. MSSU patients had a shorter length of stay, lower rates of in-hospital complications and lower rates of readmission within 30 days of discharge compared with CTU patients. Our hospitalist-run MSSU appears to offer a workable system of health care delivery for patients with acute, self-limited illness requiring a brief stay in hospital. The MSSU appeared to promote the efficient use of hospital beds without compromising patient outcomes, however, further research is required to compare the efficiency and outcomes of care directly with that provided by the traditional CTU system.

Bed Occupancy↗
PubMed2000

Long-term outcomes after deep vein thrombosis: postphlebitic syndrome and quality of life.

In this review, we critically assess the literature on the incidence of postphlebitic syndrome, risk factors for its occurrence, available therapeutic options, and its effects on quality of life. As well, we describe available tools to measure postphlebitic syndrome. Recent prospective studies indicate that postphlebitic syndrome, a chronic, potentially disabling condition characterized by leg swelling, pain, venous ectasia, and skin induration, is established by 1 year after deep vein thrombosis (DVT) in 17% to 50% of patients. The only prospectively identified risk factor for its occurrence is recurrent ipsilateral DVT. In the sole randomized study available, daily use of elastic compression stockings after proximal DVT reduced the incidence of postphlebitic syndrome by 50%. Treatment options for established postphlebitic syndrome are limited, but include compression stockings and intermittent compressive therapy with an extremity pump for severe cases. To date, quality of life after DVT has received little attention in the literature. The recent development of the VEINES-QOL questionnaire, a validated venous-disease-specific measure of quality of life, should encourage researchers to include quality of life as a routine outcome measure after DVT. There is no criterion standard for the diagnosis of postphlebitic syndrome, but a validated clinical scoring system does exist. More research on postphlebitic syndrome is needed to enable us to provide DVT patients with comprehensive, evidence-based information regarding their long-term prognosis, to help quantify the prevalence and health care burden of postphlebitic syndrome, and by identifying predictors of poor outcome, to develop new preventive strategies in patients at risk of developing this condition.

Bandages↗
PubMed1999

Clinical prediction of deep vein thrombosis in patients with leg symptoms.

Symptoms and clinical signs individually are inaccurate for the diagnosis of DVT. However, when assessing patients with leg symptoms, clinicians have access to additional information, such as whether or not DVT risk factors are present that could improve the accuracy of clinical judgment. The purpose of this study was to identify which clinical variables best predict DVT, and to use these variables to create a clinical prediction index for DVT. We studied 271 university hospital patients with a first episode of symptomatic, clinically suspected DVT. The prevalence of DVT was 27%, of which 71% were proximal. At baseline, information was collected on demographic features, comorbidity, and symptoms and signs. A Bayesian model selection strategy was used to estimate the logistic regression model that best predicted DVT. Male sex [OR = 2.8 (1.5, 5.1)], orthopedic surgery [OR = 5.4 (2.2, 13.6)], warmth [OR = 2.1 (1.2, 3.9)] and superficial venous dilation on exam [OR = 2.9 (1.4, 5.7)] were independent predictors of DVT. Using the model, a clinical prediction index that categorized patients into different levels of DVT risk was created, and was useful in a theoretical strategy aimed to limit the need for contrast venography in patients with suspected DVT, such that 96% of study patients could have avoided contrast venography. This index should be evaluated prospectively in other patient populations.

Adult↗
PubMed1999

Chronic venous disorders of the leg: epidemiology, outcomes, diagnosis and management. Summary of an evidence-based report of the VEINES task force. Venous Insufficiency Epidemiologic and Economic Studies.

BACKGROUND: To critically review the classification, epidemiology, outcomes, diagnosis and treatment of chronic venous disorders of the leg (CVDL), to issue evidence-based recommendations, and to identify areas requiring further research. METHODS: Articles identified by an extensive literature search were scored by members of an international task force. Only those articles with a moderate or strong rating for internal validity were retained. RESULTS: A scoring system weighing CVDL severity according to the probability of ulcer occurrence is proposed. Epidemiological data on the frequency of CVDL and its risk factors are reviewed. The following items are evaluated: costs associated with treatment; clinical outcomes related to CVDL and its treatment; available generic and disease-specific measures of quality of life; diagnostic procedures used to detect venous reflux; and efficacy of available treatments. CONCLUSIONS: CVDL is an important public health problem, based on its prevalence, cost and impact on quality of life. High-priority areas for research on CVDL are identified.

Chronic Disease↗
PubMed1998

The clinical diagnosis of deep venous thrombosis: integrating incidence, risk factors, and symptoms and signs.

Symptoms and clinical signs suggestive of deep venous thrombosis (DVT) are common and have numerous possible causes. Studies have shown that symptoms and clinical signs in themselves are inaccurate for the diagnosis of DVT. However, clinicians have other information at hand, such as data on risk factors for DVT, that may help improve their ability to predict a diagnosis of DVT in the individual patient. Epidemiological data on DVT incidence and risk factors were reviewed, as were published data on the accuracy of clinical diagnosis of DVT, with the use of both symptoms and signs in isolation and symptoms and signs combined with other clinical information in the form of clinical prediction indexes. Symptoms and clinical signs, when combined with other patient information such as the presence or absence of known risk factors for DVT, can improve clinical prediction considerably. Further study is needed to determine whether clinical prediction indexes have a role in improving the diagnostic process in patients with suspected DVT.

Diagnosis, Differential↗
PubMed1998

Severe preeclampsia associated with coinheritance of factor V Leiden mutation and protein S deficiency.

BACKGROUND: Inherited thrombophilic disorders are associated with an increased risk of venous thromboembolism during pregnancy. Preliminary research suggests that these disorders might also increase the risk for preeclampsia. CASE: A 29-year-old primigravida developed severe, early onset preeclampsia and postpartum deep venous thrombosis. Subsequent testing revealed coinheritance of the factor V Leiden mutation and protein S deficiency. Heparin prophylaxis was administered during two subsequent pregnancies without recurrence of either preeclampsia or venous thromboembolism. CONCLUSION: Our patient's inherited thrombophilia may have played a role in the development of preeclampsia, and anticoagulation during subsequent pregnancies may have prevented preeclampsia recurrence. An association between inherited thrombophilic disorders and preeclampsia is biologically plausible.

Adult↗
PubMed1998

Symptomatic hypocalcemia from oral sodium phosphate: a report of two cases.

The use of oral sodium phosphate has, only in very rare instances (seven cases in the literature), been recognized to cause symptomatic hypocalcemia. We report a case in an elderly woman that led to severe tetany and a 10-day admission to control the electrolyte disturbances. The patient was predisposed to developing this complication because of chronic renal failure and vitamin D deficiency. The second hypocalcemic patient had perioral tingling and numbness of the extremities but recovered quickly because of normal renal function. Magnesium depletion was a predisposing factor in the second case. These cases illustrate the rising prevalence of this disorder, which can have severe consequences and can be prevented by avoiding the prescription of these agents to high risk patient groups.

Administration, Oral↗
PubMed1997

Nonvalvular atrial fibrillation: evidence for a prothrombotic state.

OBJECTIVE: To determine whether patients with nonvalvular atrial fibrillation (NVAF) have prothrombotic changes compared with patients in sinus rhythm. DESIGN: Cross-sectional study. Hemostatic function compared in NVAF patients without prior embolic event (transient ischemic attack or embolic stroke) and control subjects without prior thrombotic stroke, and in NVAF patients with prior embolic event and control subjects with prior thrombotic stroke. SETTING: Internal medicine outpatient group practice and anticoagulation clinic in 2 teaching hospitals. PATIENTS: A total of 75 NVAF patients (50 without and 25 with prior embolic event) and 42 control patients (31 without and 11 with prior thrombotic stroke) recruited concurrently over 18 months during 1990-91. OUTCOME MEASURES: Platelet count, prothrombin time (PT), partial thromboplastin time (PTT), and plasma levels of hemoglobin, fibrinogen, von Willebrand factor antigen, factor VIII, fibrin D-dimer, antithrombin III, protein C, protein S, fibrinopeptide A and prothrombin fragment F1+2. All statistical analyses were performed after adjustments for age and sex. RESULTS: The NVAF patients without a prior embolic event had significantly higher mean hemoglobin and fibrinogen levels (p < 0.001 and p = 0.05, respectively) than the control subjects without prior thrombotic stroke. The 29 NVAF patients not taking warfarin (none had had an embolic event) had significantly lower mean protein C and protein S levels (p = 0.012 and p < 0.001, respectively) and a significantly higher fibrinopeptide A level (p = 0.03, after exclusion of outliers) than the control subjects without prior stroke. The NVAF patients with a prior embolic event had alterations in the hemostatic variables similar to those seen in the control patients with a prior thrombotic stroke. The latter had significantly higher fibrinogen, von Willebrand factor antigen and factor VIII levels (p = 0.04, 0.002 and 0.002, respectively) and significantly lower protein S levels (p = 0.02) than the control subjects without prior stroke. CONCLUSIONS: NVAF patients without a history of an embolic event show evidence of a prothrombotic state compared with patients in sinus rhythm who have not had a thrombotic stroke. NVAF patients with a history of an embolic event show evidence of a prothrombotic state similar to that of patients in sinus rhythm who have had a thrombotic stroke. Prospective studies are needed to determine whether these abnormalities predict higher risk of stroke in individual NVAF patients.

Aged↗