Exercise-induced pulmonary hypertension assessed by echocardiography in patients with chronic thromboembolic pulmonary disease

Background

Many patients with chronic thromboembolic pulmonary disease (CTEPD) without pulmonary hypertension (PH) at rest suffer from exercise intolerance. Exercise echocardiography, which is a noninvasive examination, may have potential to discover exercise-induced PH in these patients, however, its role is scarcely explored in this population.

Purpose

To determine the occurrence of abnormal pulmonary pressure during rest and by exercise echocardiography in patients with CTEPD.

Methods

In total, 24 patients with CTEPD, all diagnosed after pulmonary embolism, underwent exercise echocardiography with dynamic supine leg exercise using a cycle ergometer. In addition, all participants underwent a modified incremental shuttle walk test (mISWT), pulmonary function tests and measurement of NT pro-BNP. Systolic pulmonary arterial pressure (sPAP) >50 mmHg by echocardiography during exercise was chosen as cutoff to define exercise-induced pulmonary hypertension (EIPH). Left ventricular diastolic dysfunction during stress was defined according to the American Society of Cardiology guidelines from 2016. Mean pulmonary artery pressure was estimated by sPAP measurements using the Chemla formula (0.61 x sPAP + 2 mmHg), and pulmonary vascular resistance (PVR) by the Doppler method (5.19 x TRV2/TVI RVOT − 0.4) proposed by Abbas et al. [1]. Subjects with heart failure with reduced or preserved ejection fraction, significant valvular heart disease, chronic pulmonary disease and chronic thromboembolic pulmonary hypertension were excluded.

Results

11 (46%) of the patients had EIPH at peak exercise (range 50 to 89 mmHg). PVR at peak exercise ranged from 2.6 to 5.9 WU, whereas 10 had PVR >3.0 WU. None had unmasked left ventricular diastolic dysfunction during exercise, resting tricuspid regurgitation peak velocity (TR V max) >3.4m/s, or a high probability of PH at rest. Three patients had TR V max between 2.9 and 3.4m/s or intermediate probability of PH. All patients had normal biventricular systolic function at rest and during exercise (Table 2).

Conclusion

Patients with CTEPD had normal pulmonary pressures at rest. However, approximately half of the patients showed abnormal rise in pulmonary pressure during exercise, which may explain or contribute to the exercise intolerance in these patients.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Ostfold Hospital Trust

Exercise hemodynamics by echocardiography and right heart catheterization in patients with chronic thromboembolic pulmonary disease

Background

Chronic thromboembolic pulmonary hypertension (CTEPH) is an important cause of pulmonary hypertension (PH). A subclinical form of PH is referred to as exercise-induced pulmonary hypertension (EIPH), and its prevalence in patients with chronic thromboembolic pulmonary disease (CTEPD) without pulmonary hypertension at rest is unknown.

Purpose

To explore the occurrence of exercise-induced pulmonary hypertension (PH) in patients with CTEPD and compare exercise echocardiography with right heart catheterization (RHC).

Methods

In total, 16 patients with CTEPD, all diagnosed after pulmonary embolism, underwent exercise echocardiography and exercise RHC with dynamic supine leg exercise using a cycle ergometer. CTEPH at rest was defined as mean pulmonary artery pressure (mPAP) >20 mmHg and pulmonary vascular resistance (PVR) ≥3WU. EIPH by RHC was defined as mPAP >30 mmHg with total pulmonary resistance (TPR) ≥3 WU. Based on these criteria, our patients with CTEPD are presented by a flow chart (Figure 1). Systolic pulmonary artery pressure by echocardiography was calculated by tricuspid regurgitation peak velocity (TR V max) and the Bernoulli formula: 4 × (TR V)2. The RHC examination followed the exercise echocardiography within 2 hours. Groups were compared with independent sample t-test.

Results

Four patients (25%) were diagnosed with EIPH by exercise RHC. Patients with EIPH had a mean mPAP at peak exercise of 40.5 mmHg (range 38 to 43mmHg) and TPR of 3.7 WU (range 3.0 to 4.3 WU). The same patients also had a higher TR V max at peak exercise during exercise echocardiography compared to the patients without EIPH (Table 2). None of the patients had signs of elevated left-sided filling pressure during exercise by RHC, and none had left ventricular diastolic dysfunction during exercise by echocardiography.

Conclusion

In total, 4 of 16 patients with CTEPD were diagnosed with EIPH. The same four patients also had abnormal pulmonary artery pressure rise during exercise echocardiography and invasive RHC. These findings suggest that exercise echocardiography may be useful for screening patients with CTEPD and suspected EIPH.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Ostfold Hospital Trust

Comparison of warfarin, dabigatran, rivaroxaban and apixaban for effectiveness and safety among elderly patients with atrial fibrillation: a nationwide cohort study

Introduction

Age is a strong independent risk factor for stroke and systemic embolism (SE) in patients with atrial fibrillation (AF). Reducing risk of stroke/SE with oral anticoagulation (OAC) in elderly patients involves a correspondingly greater risk of bleeding than in younger patients. Non-vitamin K antagonist oral anticoagulants (NOACs) are associated with a net clinical benefit over vitamin K antagonists in the elderly population, but knowledge is lacking about the comparative effectiveness and safety between specific oral anticoagulants in these patients.

Purpose

The aim of this study was to compare the rates of stroke/SE and major bleeding between new users of warfarin, dabigatran, rivaroxaban, and apixaban, in a nationwide cohort of AF patients over 75 years.

Methods

From Norwegian national registries we identified all anticoagulant naïve initiators of warfarin, dabigatran, rivaroxaban and apixaban over 75 years of age between January 2013 and December 2017. During follow-up, patients were censored upon switching OAC, discontinuation of OAC, death, or end of study period. Multivariate competing risk regression was used to evaluate association between treatment and the outcomes stroke/se and major bleeding, treating death as a competing risk.

Results

A total of 30 401 patients were identified; 6 650 starting warfarin, 3 857 starting dabigatran, 6 108 starting rivaroxaban, and 13 786 starting apixaban. The median age was 82 years. Dabigatran-users had less comorbidity than all other OAC-users; the greatest difference was seen in the proportion of patients with chronic kidney disease (4.3% in the dabigatran-group versus 7.0%, 10.5%, and 16.5% in the rivaroxaban, apixaban, and warfarin groups, respectively). The median follow-up time was 15 months, during which time 1 386 (4.6%) patients suffered a stroke/SE; 1 277 (4.2%) patients had a major bleeding episode; and 3 270 (10.8%) died. Adjusted subhazard ratios for stroke/SE and major bleeding are presented in the figure.

Conclusion

Comparing NOACs with warfarin, we found no significant differences in risk of stroke/SE, while apixaban was associated with lower risk of major bleeding than warfarin. Comparing NOACs with each other; dabigatran was associated with a significantly lower risk of stroke/SE compared with rivaroxaban and apixaban, while both dabigatran and apixaban were associated with significantly lower risks of major bleeding compared with rivaroxaban.

Incidence rates and subhazard ratios

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): South-Eastern Norway regional Health Authority

Measuring functional limitations after venous thromboembolism: Optimization of the Post-VTE Functional Status (PVFS) Scale

INTRODUCTION

We recently proposed a scale for assessment of patient-relevant functional limitations following an episode of venous thromboembolism (VTE). Further development of this post-VTE functional status (PVFS) scale is still needed.

METHODS

Guided by the input of VTE experts and patients, we refined the PVFS scale and its accompanying manual, and attempted to acquire broad consensus on its use.

RESULTS

A Delphi analysis was performed involving 53 international VTE experts with diverse scientific and clinical backgrounds. In this process, the number of scale grades of the originally proposed PVFS scale was reduced and descriptions of the grades were improved. After these changes, a consensus was reached on the number/definitions of the grades, and method/timing of the scale assessment. The relevance and potential impact of the scale was confirmed in three focus groups totaling 18 VTE patients, who suggested additional changes to the manual, but not to the scale itself. Using the improved manual, the κ-statistics between PVFS scale self-reporting and its assessment via the structured interview was 0.75 (95%CI 0.58-1.0), and 1.0 (95%CI 0.83-1.0) between independent raters of the recorded interview of 16 focus groups members.

CONCLUSION

We improved the PVFS scale and demonstrated broad consensus on its relevance, optimal grades, and methods of assessing among international VTE experts and patients. The interobserver agreement of scale grade assignment was shown to be good-to-excellent. The PVFS scale may become an important outcome measure of functional impairment for quality of patient care and in future VTE trials.

P3470Comparative effectiveness and safety of non-vitamin K oral anticoagulants and warfarin in non-valvular atrial fibrillation - a cohort study in 3 Nordic countries

Background

Non-vitamin K oral anticoagulants (NOACs) are an alternative to warfarin in the prevention of stroke in non-valvular atrial fibrillation (NVAF). Nordic countries have high quality of warfarin treatment, making them an especially suitable setting for assessing effectiveness and safety of NOACs against warfarin.

Purpose

The BEYOND Pooled (BEnefit of NOACs studY of nOn-valvular AF patieNts in NorDic countries) study compared risks of ischaemic or haemorrhagic stroke/systemic embolism (S/SE), and risk of bleeding with acute hospitalisation with an overnight stay (bleeding) in NVAF patients treated with apixaban, dabigatran or rivaroxaban, each compared with warfarin treatment.

Methods

A cohort study of treatment-naïve adult NVAF patients dispensed apixaban, dabigatran, rivaroxaban or warfarin was identified from 01 Jan 2013 to 31 Dec 2016. The population and study variables were identified from national registries in Denmark, Norway and Sweden. After 1:1 propensity score (PS) matching for each NOAC-warfarin comparison, individual-level data were pooled across the countries. Cox proportional-hazards regression was used to estimate adjusted hazard ratios (aHRs) of the endpoints.

Results

PS matched NOAC cohort sizes were: apixaban (55,696) dabigatran (28,526) and rivaroxaban (30,701), and the total follow-up in the PS-matched population was 291,171 years (mean 1.3 years). During the follow-up, 35,450 oral anticoagulation (OAC) patients had a S/SE and 38,620 OAC patients had bleeding. Adjusted HRs for the two endpoints are presented in the table. PH assumption has not been formally tested but cum incidence curves did not indicate substantial differences in the effects over time.

Table 1. Adjusted hazard ratios (aHR) of stroke/systemic embolism and bleeding for non-vitamin K oral anticoagulants versus warfarin Endpoint Apixaban vs Warfarin: aHR (95% CI) Dabigatran vs Warfarin: aHR (95% CI) Rivaroxaban vs Warfarin: aHR (95% CI) Stroke/SE 0.93 (0.85–1.03) 0.89 (0.80–1.00) 0.97 (0.88–1.08) Bleeding 0.72 (0.67–0.77) 0.87 (0.80–0.95) 1.12 (1.04–1.20)

Conclusions

Relative to warfarin, apixaban and dabigatran were associated with lower rates of bleeding whereas rivaroxaban was associated with a higher rate. The three NOACs had comparable rates of stroke and systemic embolism relative to warfarin.

Acknowledgement/Funding

This study was funded by the Pfizer/Bristol-Myers Squibb Alliance.

P2766Increased right ventricular burden in patients with chronic thromboembolic disease

Introduction

Patients with chronic thromboembolic disease (CTED) have residual perfusion defects after pulmonary embolism (PE) but not increased pulmonary artery (PA) pressure. These patients suffer from functional limitation and have a higher risk of venous thromboembolism recurrence.

Purpose

In this study we wanted to explore if CTED patients had signs of increased PA pressure and right heart burden by echocardiography

Methods

Inclusion criteria were history of PE, age 18–75 years and PE diagnosed 6–72 months prior to inclusion. Patients with left ventricular systolic or diastolic heart failure, valvular disease, chronic pulmonary disease and chronic thromboembolic pulmonary hypertension were excluded. All patients underwent echocardiography with standard and novel methods and ventilation/perfusion (VQ)-scan. The echocardiographic examinations were blinded to the result of the VQ-scan. VQ-scan were analyzed according to the European Association of Nuclear Medicine-criteria, and deemed either positive or negative. Data are presented as mean ± SD or median ± IQR as appropriate. Independent sample t-test or Mann-Whitney U test was used for the primary statistical analysis. Multiple linear regression was used to adjust for age, BMI and systolic blood pressure.

Results

Conclusion

Patients with CTED after PE have increased PA pressure and impaired RV systolic and diastolic function compared to those without residual perfusion defects. These findings indicate that CTED patients should be more thoroughly followed up.

P5288Slice position vulnerability in the basal and apical parts for right ventricular circumferential strain measurement with feature tracking cardiac magnetic resonance

Background

Strain is a more sensitive and precise parameter than ejection fraction (EF) for detection and characterization of subclinical left ventricular (LV) dysfunction and remodeling. Similar relationship is expected for right ventricle (RV); however RV functional parameters are less validated. Feature tracking strain analysis based on standard cardiac magnetic resonance (CMR) cine imaging is available for both ventricles. We experience a large slice-to-slice variation for RV global circumferential strain (GCS), possibly making the parameter vulnerable to minute position changes.

Purpose

To evaluate slice-to-slice differences in RV GCS for identification of the least variation region in a patient group without regional RV disease, in order to achieve a robust method for measurement.

Hypothesis

The slice-to-slice difference in peak GCS is lower in the mid-ventricular part of the RV than in the basal and apical parts.

Methods

50 patients 6–72 months after pulmonary embolism without other major cardiopulmonary disease were included; mean age 60 years (range: 18–75 years); 68% men.

Standard 2D cine CMR was obtained in longitudinal planes and in 10–12 consecutive 10 mm short axis planes for complete coverage of the RV. RV free wall and the inner contour of the septum were manually segmented on every end-diastolic and end-systolic slice from the pulmonary valve to the apex for feature tracking strain analysis.

Peak RV GCS for every short axis slice and GCS difference (absolute percentage points) between adjacent slices were calculated. RV EF and peak RV GLS from the 4-chamber image were measured for correlation to RV GCS. Wilcoxon signed rank test and Pearson correlation were performed. Confidence intervals of means are based on 1000 bootstrap samples.

Results

RV EF was 46.6% (95% CI: 44.3; 48.8), RV peak GLS was −17.6% (95% CI: −18.6; −16.6). RV mid-ventricular GCS was −10.9% (95% CI: −12.0; −9.9). RV peak GCS slice-to-slice difference was 6.8 absolute percentage points (95% CI: 6.0; 7.6) in the basal part, 2.7 (95% CI: 2.4; 3.0) in the mid-ventricular part and 4.6 (95% CI: 3.9; 5.3) apically. Difference was significantly lower in mid-ventricular (p<0.001) compared to both basal and apical.

RV EF correlated to RV peak GLS (r: −0.397, p=0.004) and mid-ventricular peak GCS (r: −0.356, p=0.01) but not to basal or apical peak GCS. RV peak GLS correlated to basal and mid-ventricular peak GCS (r: 0.313, p=0.03 and r: 0.301, p=0.03 respectively) but not to apical peak GCS.

Figure 1 shows slice-to-slice difference (expressed in absolute percentage points) in right ventricular peak GCS.

Conclusion

Slice-to-slice difference in RV peak GCS was significantly lower in the mid-ventricular region. Large differences in the basal and apical parts indicate that measurements largely depend on slice positioning.

Safety of D-dimer testing as a stand-alone test for the exclusion of deep vein thrombosis as compared with other strategies

Essentials The aim of deep vein thrombosis (DVT) diagnostic work-up is to maximize both safety and efficiency. We explored whether D-dimer is safe and efficient as a stand-alone test to exclude DVT. Our findings suggest it is a safe, efficient and simplified diagnostic strategy. The safety of age-adjusted D-dimer as a stand-alone test requires further investigation. SUMMARY: Background Several strategies for safely excluding deep vein thrombosis (DVT) while limiting the number of imaging tests have been explored. Objectives To determine whether D-dimer testing could safely and efficiently exclude DVT as a stand-alone test, and evaluate its performance as compared with strategies that incorporate the Wells score and age-adjusted D-dimer. Patients/Methods We included consecutive outpatients referred with suspected DVT to the Emergency Department at Østfold Hospital, Norway. STA-Liatest D-Di PLUS D-dimer was analyzed for all patients. Patients with a D-dimer level of ≥ 0.5 μg mL-1 were referred for compression ultrasonography (CUS). In patients with a D-dimer level of < 0.5 μg mL-1 , no further testing was performed and anticoagulation was withheld. Patients were followed for 3 months for venous thromboembolism (VTE). Results Of the 913 included patients, 298 (33%) had a negative D-dimer result. One hundred and seventy-three patients (18.9%) were diagnosed with DVT at baseline. One of 298 patients had DVT despite having a negative D-dimer result, resulting in a failure rate of 0.3% (95% confidence interval [CI] 0.1-1.9%). Adding the modified Wells score would have yielded a failure rate of 0.0% (95% CI 0.0-1.8%) while necessitating 87 more CUS examinations. Age-adjusted D-dimer as a stand-alone test would have necessitated 80 fewer CUS examinations than fixed D-dimer as a stand-alone test, at the cost of a failure rate of 1.6% (95% CI 0.7-3.4%). Conclusions This outcome study shows that a negative high-sensitivity D-dimer result safely excludes DVT in an outpatient population, and necessitates fewer CUS than if used in combination with Wells score. The safety of stand-alone age-adjusted D-dimer needs further assessment in prospective outcome studies.

JAK2 V617F mutation can be reliably detected in serum using droplet digital PCR

INTRODUCTION

Detection of the JAK2 V617F mutation is a key step in the diagnosis of myeloproliferative neoplasms (MPN). Sensitive real-time quantitative PCR (qPCR) detection on peripheral blood (PB) is the most widely used method. The main objective of this study was to determine whether serum, the most common material available in archival biobanks, is a good liquid biopsy for detecting and quantifying the JAK2 V617F mutation using droplet digital PCR (ddPCR).

METHODS

Paired PB and serum samples from 66 patients with MPN were used. Serum samples were frozen at -25°C before analysis. DNA was extracted from 200 μL PB and 400 μL serum, and ddPCR analysis was performed.

RESULTS

Among the 47 patients with detectable mutation in their PB samples, the overall sensitivity for the detection of JAK2 mutation in serum was of 96% (45 of 47); V617F was detected in all cases where mutation load was above 1%. Our results showed very strong correlation between PB and serum (Spearman r: 0.989, P < .0001). Significantly higher allele burden was detected in serum compared to PB (Wilcoxon signed ranks test, Z = -5.672, P < .0001).

CONCLUSION

In our study, JAK2 V617F mutation load as low as 1% was reliably detected in serum using ddPCR.

Decreased plasma cytokines are associated with low platelet counts in aplastic anemia and immune thrombocytopenic purpura

BACKGROUND

We previously found plasma levels of CD40 ligand (CD40L), chemokine (C-X-C motif) ligand 5 (CXCL5), chemokine (C-C motif) ligand 5 (CCL5) and epidermal growth factor (EGF) to be low in aplastic anemia (AA) patients and to be correlated with platelet count.

OBJECTIVES

To study the association of CD40L, CXCL5, CCL5 and EGF with platelets.

METHODS

We measured cytokines in the plasma of immune thrombocytopenic purpura (ITP) and AA patients using the Luminex assay and confirmed the results in a mouse model and in vitro experiments.

RESULTS

Both ITP and AA showed similarly low levels of CD40L, CXCL5, CCL5 and EGF, compared with healthy controls. In ITP, levels of these proteins were significantly greater in patients with higher platelet counts than in those with lower platelet counts. In a murine thrombocytopenia model, levels of CD40L, CXCL5, CCL5 and EGF decreased with platelet count after immune-mediated destruction, while the cytokine levels increased when the platelet count recovered. In vitro, concentrations of these cytokines in the supernatants of platelet suspensions were proportional to platelet numbers, and levels in sera prepared by simple blood coagulation were equivalent to those in platelet-rich plasma-converted sera. mRNA expression for CXCL5, CCL5 and EGF was higher in platelets than in megakaryocytes, peripheral blood mononuclear cells, granulocytes and non-megakaryocytic bone marrow cells.

CONCLUSIONS

Plasma CD40L, CXCL5, CCL5 and EGF are mainly platelet-derived, suggesting a role of platelets in immune responses and inflammation. Measurement of CD40L, CXCL5, CCL5 and EGF in human blood allowed testable inferences concerning physiology and pathophysiology in quantitative platelet disorders.

Catheter-directed thrombolysis vs. anticoagulant therapy alone in deep vein thrombosis: results of an open randomized, controlled trial reporting on short-term patency

BACKGROUND

Approximately one in four patients with acute proximal deep vein thrombosis (DVT) given anticoagulation and compression therapy develop post-thrombotic syndrome (PTS). Accelerated removal of thrombus by thrombolytic agents may increase patency and prevent PTS.

OBJECTIVES

To assess short-term efficacy of additional catheter-directed thrombolysis (CDT) compared with standard treatment alone.

PATIENTS AND METHODS

Open, multicenter, randomized, controlled trial. Patients (18-75 years) with iliofemoral DVT and symptoms < 21 days were randomized to receive additional CDT or standard treatment alone. After 6 months, iliofemoral patency was investigated using duplex ultrasound and air-plethysmography assessed by an investigator blinded to previous treatment.

RESULTS

One hundred and three patients (64 men, mean age 52 years) were allocated additional CDT (n = 50) or standard treatment alone (n = 53). After CDT, grade III (complete) lysis was achieved in 24 and grade II (50%-90%) lysis in 20 patients. One patient suffered major bleeding and two had clinically relevant bleeding related to the CDT procedure. After 6 months, iliofemoral patency was found in 32 (64.0%) in the CDT group vs. 19 (35.8%) controls, corresponding to an absolute risk reduction (RR) of 28.2% (95% CI: 9.7%-46.7%; P = 0.004). Venous obstruction was found in 10 (20.0%) in the CDT group vs. 26 (49.1%) controls; absolute RR 29.1% (95% CI: 20.0%-38.0%; P = 0.004). Femoral venous insufficiency did not differ between the two groups.

CONCLUSIONS

After 6 months, additional CDT increased iliofemoral patency from 36% to 64%. The ongoing long-term follow-up of this study will document whether patency is related to improved functional outcome.

Multidetector computed tomography (MDCT) in the diagnosis of pulmonary embolism: interobserver agreement among radiologists with varied levels of experience

PURPOSE

To assess the interobserver variability of radiologists with varied levels of experience in the interpretation of multidetector computed tomography (MDCT) pulmonary angiographies.

MATERIAL AND METHODS

Review of CT pulmonary angiographies performed on patients included in a diagnostic study evaluating a decision-based algorithm for diagnosing pulmonary embolism (PE). Five radiologists, three board-certified general radiologists and two radiology trainees with 2 years' experience, participated in the study.

RESULTS

According to the consensus reading, PE was present in 91 (31%) and absent in 194 (67%) patients, while in five patients (1.7%) the interpretations were regarded as equivocal. The per-patient agreement on the diagnosis of PE achieved by each of the four readers compared to the consensus reading was very good (kappa range 0.85-0.92), but peripheral emboli were missed in four to six patients by three of four observers. The agreement on the most proximal level of PE (per-proximal level) assessed by mean kappa value was 0.83 (kappa range 0.68-0.91) for the detection of proximal emboli, 0.61 for segmental emboli (kappa range 0.40-0.80), and 0.38 for emboli in the subsegmental vessels (kappa range 0.0-0.89).

CONCLUSION

The overall agreement on the diagnosis of PE by MDCT for general radiologists and radiology trainees is very good, and we therefore believe that the initial management of patients with suspected PE could be based on the preliminary assessment performed by on-call radiologists with 2 years of experience.

The association between the proximal extension of the clot and the severity of pulmonary embolism (PE): a proposal for a new radiological score for PE

BACKGROUND

The aim of the study was to investigate the association between the proximal level of the clot and the severity of pulmonary embolism (PE).

METHODS

The cohort consisted of 99 consecutive patients with PE diagnosed by multi-detector computed tomography. A new score was constructed by calculating the mean value of the largest affected vessel [sub-segmental = 1, segmental = 2, lobar = 3, main pulmonary artery (MPA) = 4] in each lung.

RESULTS

A significant association was found between the most proximal level of PE and pulmonary artery obstruction index (PAOI) (P < 0.0001), right ventricular (RV)/left ventricular (LV) ratio (P < 0.0001), and PaO(2) (P = 0.004). No significant association was found between systolic blood pressure and the level of PE. Troponin-T was elevated in none of the sub-segmental, 5% of segmental, 20% of lobar, and in 56% of PEs in the MPA (P = 0.001). Significant association was found between the proposed score and PAOI (P < 0.0001), RV/LV ratio (P < 0.0001), PaO(2) (P < 0.008). Troponin-T was elevated in 10% of level 1, 0% of level 2, 43% level of 3, 66% of level 4 PE (P < 0.0001). Cut-off level score 4 yielded a sensitivity of 84% and a specificity of 74% for the detection of elevated troponin-T.

CONCLUSIONS

In conclusion, the study indicates that both the most proximal level of PE and the proposed score are related to the severity of PE as determined by blood oxygenation, biochemical and radiological parameters and could therefore be of value for rapid risk stratification of PE. However, the prognostic value of these classifications and their clinical significance needs to be evaluated in properly designed studies.

D-dimer level is associated with the extent of pulmonary embolism

OBJECTIVES

Our aim was to study the association between the level of D-dimer and the severity of pulmonary embolism (PE) as determined by various biochemical and radiological prognostic markers in order to investigate the potential value of D-dimer as a prognostic marker for the severity of PE.

PATIENTS AND METHODS

PE was diagnosed in 100 consecutive out-patients by multi-detector computerized tomography. One patient was excluded and the final cohort consisted of 99 patients. Pulmonary Artery Obstruction Index (PAOI) and Right Ventricular/Left Ventricular (RV/LV) ratio were assessed.

RESULTS

The median value for D-dimer was 5.0 mg/L (inter-quartile range: 1.8, 12.2). There was a significant association between log D-dimer, and between log RV/LV (r=0.45), log PAOI (r=0.5), and PaO(2) (r=0.40). The multivariate analysis showed an increased association between log D-dimer and between log RV/LV ratio (r=0.54) and log PAOI (r=0.52) after adjusting for age, gender and for the duration of symptoms. Significant association was found between the level of D-dimer and the most proximal level of PE (p<0.0005). There was a significant dose-response relationship between the level D-dimer and between Troponin-T and the frequency of thrombolysis (p<0.0005). In the subgroup of patients with D-Dimer over the upper quartile (>12.2), 12 (67%) patients had elevated Troponin-T and 8 (32%) patients received thrombolysis, compared to 1 (5%) patient with elevated Troponin-T and none treated with thrombolysis in the subgroup of patients with D-dimer<lower quartile.

CONCLUSIONS

We have shown that the level of D-dimer is related to the severity of PE assessed by various radiological, biochemical and clinical markers and might have a potential value as prognostic marker for the severity of PE.

Validation of a new D-dimer microparticle enzyme immunoassay (AxSYM D-Dimer) in patients with suspected pulmonary embolism (PE)

OBJECTIVES

The aim of the study was to evaluate a new automated assay for D-dimer testing (AxSYM D-Dimer) based on microparticle enzyme-immunoassay technology by comparing it with three well established D-dimer assays.

PATIENTS AND METHODS

The performance of the new assay was evaluated in 280 plasma samples that were collected prospectively from out-patients included in a management study evaluating a decision based algorithm.

RESULTS

58/280 patients (21%) had PE diagnosed by CT. Median values of AxSYM D-dimer in patients with PE were 3689 ng/mL (range 775-9000). Comparison analysis displayed excellent agreement with VIDAS (kappa=0.84) and Asserachrom (kappa=0.81) D-dimer assays. A strong correlation was found between AxSYM and the VIDAS (r=0.96) and Asserachrom (r=0.89) D-dimer assays. The highest cut-off value for AxSYM that yielded a sensitivity of 100% was 765 ng/mL with a specificity of 50%. At the cut-off level <500 ng/mL, the sensitivity and specificity of AxSYM D-dimer were 100% and 34%; VIDAS 100% and 42%; Asserachrom 100% and 40%; and STALiatest 100% and 37%, respectively. AxSYM D-dimer was negative in 75 patients (33.8%). None of these had PE at the initial work-up or VTE during the 3-month follow-up.

CONCLUSIONS

AxSYM D-dimer seems to be safe and effective in ruling out PE in out-patients. The cut-off level can be set at 500 to 750 ng/mL, at which the assay displays a performance that is comparable to that of the ELISA based assays. However, further studies are needed to confirm the safety of the assay and to determine the most optimal cut-off level in patients with venous thromboembolism.

The performance of STA-Liatest D-dimer assay in out-patients with suspected pulmonary embolism

Several studies have shown that D-dimer can reliably rule out pulmonary embolism (PE) in out-patients. However, various assays have different sensitivities and specificities to detect thrombosis. Our aim was to evaluate the performance of STA-Liatest D-Di in out-patients referred for suspected PE in a prospective outcome study. 495 consecutive patients referred to Østfold Hospital Trust-Fredrikstad, Norway for suspected PE between February 2002 and December 2003, were recruited in a study evaluating a decision-based algorithm combining clinical probability (CP), D-dimer, and multi-slice computer tomography (MSCT). D-dimer was performed as a first step test. No further testing was carried out in patients with D-dimer < or =0.4 mg/l and low/intermediate CP. The remaining patients proceeded to MSCT. All patients were followed up for 3 months to assess the 3-month thromboembolic risk. The final cohort consisted of 432 patients. PE was diagnosed in 102 (23%) patients. At a D-dimer cut-off point of 0.4 mg/l the tests had the highest sensitivity (100%) and specificity (36%). It safely ruled out PE in 120 (28%) patients. Kappa-coefficients for comparisons versus VIDAS and Asserachrom showed good concordance. STA-Liatest is a reliable and effective assay that can safely rule out PE in out-patients with a performance comparable with that of enzyme-linked immunosorbent assay-based d-dimer levels.

Management of suspected pulmonary embolism (PE) by D-dimer and multi-slice computed tomography in outpatients: an outcome study

OBJECTIVES

A prospective outcome study designed to evaluate a simple strategy for the management of outpatients with suspected pulmonary embolism (PE), based on clinical probability, D-dimer, and multi-slice computed tomography (MSCT).

METHODS

A cohort of 432 consecutive patients admitted to the emergency department with suspected PE was managed by sequential non-invasive testing. Patients in whom PE was ruled out were not given anticoagulants, but were followed-up for 3 months.

RESULTS

Normal D-dimer and low-intermediate clinical probability ruled out PE in 103 patients [24% (95% CI 20-28)]. Seventeen patients had normal D-dimer, but high clinical probability and proceeded to MSCT. All patients proved negative for PE. A total of 329 (76%) patients underwent MSCT examination. Pulmonary embolism was diagnosed in 93 patients [21.5% (95% CI 18-26)] and was ruled out by negative MSCT in 221 patients [51% (95% CI 46-56)]. MSCT scans were determined as inconclusive in 15 (4.5%) patients. No patient developed objectively verified venous thromboembolism (VTE) during the 3-month follow-up period. However, the cause of death was adjudicated as possibly related to PE in two patients, resulting in an overall 3-month VTE risk of 0.6% (95% CI 0-2.2%). The diagnostic algorithm yielded a definite diagnosis in 96.5% of the patients.

CONCLUSIONS

This simple and non-invasive strategy combining clinical probability, D-dimer, and MSCT for the management of outpatients with suspected PE appears to be safe and effective.

[Time delay in the thrombolytic treatment of myocardial infarction]

INTRODUCTION

Thrombolytic treatment is central in the treatment of patients with myocardial infarction.

MATERIAL AND METHODS

A cross-sectional study was conducted to determine the time delay incurred in thrombolytic treatment of patients with myocardial infarction in Ostfold Hospital, Fredrikstad, Norway. Over a seven-month period, 317 patients were diagnosed as having myocardial infarction. 80 patients (25%) received thrombolytic therapy, 68 of whom (85%) were eligible for the study. 12 patients were excluded either because of not meeting the inclusion criteria or because of incomplete data.

RESULTS

The following median times were recorded: from onset of chest pain till first contact with the health care services, 59 minutes; from first contact till arrival at hospital, 32 minutes; from hospital arrival till initiation of treatment, 40 minutes; from onset of chest pain till initiation of treatment, 147 minutes. 38% of the patients received thrombolysis within 120 minutes of pain onset, and 35% received treatment within 30 minutes of arrival in hospital. There was no difference in time delay before contacting health care services among patients with or without a previous history of coronary heart disease, except for those who took nitroglycerine at onset of symptoms. They had the longest time delay.

INTERPRETATION

In order to reduce time delay, doctors should give better instructions to patients with a previous history of coronary heart disease and conduct regular training programmes for hospital interns and nurses. It is further assumed that prehospital ECG and direct admission to the coronary care unit, or initiation of thrombolysis in the emergency department or in the ambulance, would result in a considerable reduction in time delay.