Fadi Matta

Acute pulmonary embolism: sensitivity and specificity of ventilation-perfusion scintigraphy in PIOPED II study.

PURPOSE To use Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) II data to retrospectively determine sensitivity and specificity of ventilation-perfusion (V/Q) scintigraphic studies categorized as pulmonary embolism (PE) present or PE absent and the proportion of patients for whom these categories applied. MATERIALS AND METHODS The PIOPED II study had institutional review board approval at all participating centers. Patient informed consent was obtained; the study was HIPAA compliant. Approval and consent included those for future retrospective research. Patients in the PIOPED II database of clinical and imaging results were included if they had diagnosis at computed tomographic (CT) angiography, Wells score, and diagnosis at V/Q scanning. V/Q scan central readings were recategorized as PE present (PIOPED II reading = high probability of PE), PE absent (PIOPED II reading = very low probability of PE or normal), or nondiagnostic (PIOPED II reading = low or intermediate probability of PE). A composite reference standard was used: the PIOPED II digital subtraction angiographic (DSA) result, or if there was no definitive DSA result, CT angiographic results that were concordant with the Wells score (ie, positive CT angiographic result and Wells score > 2 or negative CT angiographic result and Wells score < 6). Sensitivity and specificity of recategorized central readings were computed. RESULTS With the exclusion of patients with intermediate or low probability, the sensitivity of a high probability (PE present) scan finding was 77.4% (95% confidence interval [CI]: 69.7%, 85.0%), while the specificity of very low probability or normal (PE absent) scan finding was 97.7% (95% CI: 96.4%, 98.9%). The percentage of patients with a PE present or PE absent scan finding was 73.5% (95% CI: 70.7%, 76.4%). CONCLUSION In a population similar to that in PIOPED II, results of V/Q scintigraphy can be diagnostically definitive in a majority of patients; thus, it can be considered an appropriate pulmonary imaging procedure in patients for whom CT angiography may be disadvantageous.

Thrombolytic Therapy in Unstable Patients with Acute Pulmonary Embolism: Saves Lives but Underused

BACKGROUND Data are sparse and inconsistent regarding whether thrombolytic therapy reduces case fatality rate in unstable patients with acute pulmonary embolism. We tested the hypothesis that thrombolytic therapy reduces case fatality rate in such patients. METHODS In-hospital all-cause case fatality rate according to treatment was determined in unstable patients with pulmonary embolism who were discharged from short-stay hospitals throughout the United States from 1999 to 2008 by using data from the Nationwide Inpatient Sample. Unstable patients were in shock or ventilator dependent. RESULTS Among unstable patients with pulmonary embolism, 21,390 of 72,230 (30%) received thrombolytic therapy. In-hospital all-cause case fatality rate in unstable patients with thrombolytic therapy was 3105 of 21,390 (15%) versus 23,820 of 50,840 (47%) without thrombolytic therapy (P<.0001). All-cause case fatality rate in unstable patients with thrombolytic therapy plus a vena cava filter was 505 of 6630 (7.6%) versus 4260 of 12,850 (33%) with a filter alone (P<.0001). Case fatality rate attributable to pulmonary embolism in unstable patients was 820 of 9810 (8.4%) with thrombolytic therapy versus 1080 of 2600 (42%) with no thrombolytic therapy (P<.0001). Case fatality rate attributable to pulmonary embolism in unstable patients with thrombolytic therapy plus vena cava filter was 70 of 2590 (2.7%) versus 160 of 600 (27%) with a filter alone (P<.0001). CONCLUSION In-hospital all-cause case fatality rate and case fatality rate attributable to pulmonary embolism in unstable patients was lower in those who received thrombolytic therapy. Thrombolytic therapy resulted in a lower case fatality rate than using vena cava filters alone, and the combination resulted in an even lower case fatality rate. Thrombolytic therapy in combination with a vena cava filter in unstable patients with acute pulmonary embolism seems indicated.

Impact of Vena Cava Filters on In-hospital Case Fatality Rate from Pulmonary Embolism

BACKGROUND The effects of vena cava filters on case fatality rate are not clear, although they are used increasingly in patients with pulmonary embolism. The purpose of this investigation is to determine categories of patients with pulmonary embolism in whom vena cava filters reduce in-hospital case fatality rate. METHODS In-hospital all-cause case fatality rate according to the use of vena cava filters was determined in patients with pulmonary embolism discharged from short-stay hospitals throughout the United States using data from the Nationwide Inpatient Sample. RESULTS In-hospital case fatality rate was marginally lower in stable patients who received a vena cava filter: 21,420 of 297,700 (7.2%) versus 135,240 of 1,712,800 (7.9%) (P<.0001). Filters did not improve in-hospital case fatality rate if deep venous thrombosis was diagnosed in stable patients. A few stable patients (1.4%) received thrombolytic therapy. Such patients who received a vena cava filter had a lower case fatality rate than those who did not: 550 of 8550 (6.4%) versus 2950 of 19,050 (15%) (P<.0001). Unstable patients who received thrombolytic therapy had a lower in-hospital case fatality rate with vena cava filters than those who did not: 505 of 6630 (7.6%) versus 2600 of 14,760 (18%) (P<.0001). Unstable patients who did not receive thrombolytic therapy also had a lower in-hospital case fatality rate with a vena cava filter: 4260 of 12,850 (33%) versus 19,560 of 38,000 (51%) (P<.0001). CONCLUSION At present, it seems prudent to consider a vena cava filter in patients with pulmonary embolism who are receiving thrombolytic therapy and in unstable patients who may not be candidates for thrombolytic therapy. Future prospective study is warranted to better define in which patients a filter is appropriate.

Increasing Use of Vena Cava Filters for Prevention of Pulmonary Embolism

PURPOSE To test whether the use of vena cava filters continues to increase in the era of retrievable filters, suggesting that indications for insertion are broadening. METHODS Data from 1979 through 2006 are from the National Hospital Discharge Survey. RESULTS From 1979 through 1984, 17,000 vena cava filters were inserted; 8000 in patients with pulmonary embolism, 4000 in patients with deep venous thrombosis only, and 5000 in patients at risk of pulmonary embolism who had neither. From 1985 through 2006, 803,000 vena cava filters were inserted: 285,000 in patients with pulmonary embolism, 360,000 in patients with deep venous thrombosis only, and 158,000 in patients who had neither. The largest proportional increases in the use of vena cava filters since the introduction of retrievable filters was in patients at risk of pulmonary embolism but who had neither pulmonary embolism nor deep venous thrombosis. The trend toward increased use in this group began before retrievable filters were introduced. There was a 3-fold increase from 2001-2006. CONCLUSION Extensive use of permanent and retrievable vena cava filters in the US indicates liberalization of indications. It would seem that a more discriminate use of vena cava filters would be appropriate at the present time, keeping an open mind for broadened indications as data accrue.

CT Venography and Compression Sonography Are Diagnostically Equivalent: Data from PIOPED II

OBJECTIVE The purpose of this study was to compare the clinical value of CT venography (CTV) after MDCT angiography (CTA) with venous compression sonography for the diagnosis of venous thromboembolism (VTE). The Prospective Investigation of Pulmonary Embolism Diagnosis II (PIOPED II) showed that lower extremity imaging detects about 7% more patients requiring anticoagulation than CTA alone. SUBJECTS AND METHODS PIOPED II was a prospective multicenter study investigating the accuracy of CTA alone and CTA and CTV together. A composite reference standard was used to confirm, or rule out, pulmonary embolus. Adequate quality CTV and sonographic images were obtained in 711 patients. RESULTS There was 95.5% concordance between CTV and sonography for the diagnosis or exclusion of deep venous thrombosis (DVT); the kappa statistic was 0.809. The sensitivity and specificity of combined CTA and CTV were equivalent to those of combined CTA and sonography. Diagnostic results in subgroups, including patients with signs or symptoms of DVT, asymptomatic patients, and patients with a history of DVT, were similar whether CTV or sonography was used. Patients with signs or symptoms of DVT were eight times more likely to have DVT, and patients with a history of DVT were twice as likely to have positive findings. CONCLUSION CTV and sonography showed similar results in diagnosing or excluding DVT. The incidence of positive studies in patients without signs, symptoms, or history of DVT is low. In terms of clinical significance, CT venography and lower extremity sonography yield equivalent diagnostic results; the incidence of positive studies in patients without signs, symptoms, or history of DVT is low; thus the choice of imaging technique can be made on the basis of safety, expense, and time constraints.

Silent pulmonary embolism in patients with deep venous thrombosis: a systematic review.

PURPOSE To determine, by systematic review of the literature, the prevalence of silent pulmonary embolism in patients with deep venous thrombosis. METHODS Twenty-eight included published investigations were identified through PubMed. Studies were selected if methods of diagnosis of pulmonary embolism were described; if pulmonary embolism was stated to be asymptomatic; and if raw data were presented. Studies were stratified according to whether silent pulmonary embolism was diagnosed by a high-probability ventilation-perfusion lung scan using criteria from the Prospective Investigation of Pulmonary Embolism Diagnosis, computed tomography pulmonary angiography, or conventional pulmonary angiography (Tier 1), or by lung scans based on non-Prospective Investigation of Pulmonary Embolism Diagnosis criteria (Tier 2). RESULTS Silent pulmonary embolism was diagnosed in 1665 of 5233 patients (32%) with deep venous thrombosis. This is a conservative estimate because many of the investigations used stringent criteria for the diagnosis of pulmonary embolism. The incidence of silent pulmonary embolism was higher with proximal deep venous thrombosis than with distal deep venous thrombosis. Silent pulmonary embolism seemed to increase the risk of recurrent pulmonary embolism: 25 of 488 (5.1%) with silent pulmonary embolism versus 7 of 1093 (0.6%) without silent pulmonary embolism. CONCLUSION Silent pulmonary embolism sometimes involved central pulmonary arteries. Because approximately one third of patients with deep venous thrombosis have silent pulmonary embolism, routine screening for pulmonary embolism may be advantageous.

Enlarged Right Ventricle Without Shock in Acute Pulmonary Embolism: Prognosis

OBJECTIVE An unsettled issue is the use of thrombolytic agents in patients with acute pulmonary embolism (PE) who are hemodynamically stable but have right ventricular (RV) enlargement. We assessed the in-hospital mortality of hemodynamically stable patients with PE and RV enlargement. METHODS Patients were enrolled in the Prospective Investigation of Pulmonary Embolism Diagnosis II. Exclusions included shock, critical illness, ventilatory support, or myocardial infarction within 1 month, and ventricular tachycardia or ventricular fibrillation within 24 hours. We evaluated the ratio of the RV minor axis to the left ventricular minor axis measured on transverse images during computed tomographic angiography. RESULTS Among 76 patients with RV enlargement treated with anticoagulants and/or inferior vena cava filters, in-hospital deaths from PE were 0 of 76 (0%) and all-cause mortality was 2 of 76 (2.6%). No septal motion abnormality was observed in 49 patients (64%), septal flattening was observed in 25 patients (33%), and septal deviation was observed in 2 patients (3%). No patients required ventilatory support, vasopressor therapy, rescue thrombolytic therapy, or catheter embolectomy. There were no in-hospital deaths caused by PE. There was no difference in all-cause mortality between patients with and without RV enlargement (relative risk=1.04). CONCLUSION In-hospital prognosis is good in patients with PE and RV enlargement if they are not in shock, acutely ill, or on ventilatory support, or had a recent myocardial infarction or life-threatening arrhythmia. RV enlargement alone in patients with PE, therefore, does not seem to indicate a poor prognosis or the need for thrombolytic therapy.

Diagnosis and Management of Isolated Subsegmental Pulmonary Embolism: Review and Assessment of the Options

We assessed the potential safety of withholding treatment of pulmonary embolism (PE) limited to subsegmental branches. Literature review showed that untreated patients with mostly subsegmental PE had no fatal recurrences in 1 to 3 months and no nonfatal recurrences of PE in 3 months. Patients with suspected PE who had nondiagnostic ventilation/perfusion lung scans, adequate cardiorespiratory reserve or low or moderate clinical probability, and negative serial noninvasive leg tests were shown not to require treatment. It appears safe, therefore, to withhold treatment of subsegmental PE providing (1) pulmonary–respiratory reserve is good; (2) no evidence of deep venous thrombosis (DVT) on serial testing; (3) major risk factor for PE was transient and no longer present; (4) no history of central venous catheterization or atrial fibrillation; and (5) willingness to return for serial venous ultrasound. After fully informing patients, some may choose to be treated and some may choose not to be treated.

Risk of venous thromboembolism with rheumatoid arthritis.

Rheumatoid arthritis is not generally considered to be a risk factor for venous thromboembolism (VTE), although abnormalities of coagulation factors have been found in patients with rheumatoid arthritis. Sparse data in a few patients suggest that patients with rheumatoid arthritis may have higher rates of VTE. The purpose of this investigation was to determine if the incidences of pulmonary embolism (PE) and deep venous thrombosis (DVT) are increased in hospitalized patients with rheumatoid arthritis. The number of patients discharged from non-Federal short-stay hospitals throughout the United States from 1979 through 2005 with a discharge code for rheumatoid arthritis was obtained from the National Hospital Discharge Survey (NHDS). Among hospitalized patients with rheumatoid arthritis who did not have joint surgery, 41,000 of 4,818,000 (0.85%) had PE compared with 3,366,000 of 891,055,000 (0.38%) among patients who did not have rheumatoid arthritis and who did not have operations or joint surgery (relative risk = 2.25). Deep venous thrombosis was diagnosed in 79,000 of 4,818,000 (1.64%) patients with rheumatoid arthritis and no joint operation, versus 7,681,000 of 891,055,000 (0.86%) who did not have rheumatoid arthritis or a joint operation (relative risk = 1.90). The relative risk of venous thromboembolism (PE and/or DVT) in these patients was 1.99. The data suggest that rheumatoid arthritis is a risk factor for VTE in hospitalized medical patients. A heightened awareness of the risks for VTE and a lower threshold for evaluation of patients for possible DVT or PE would be appropriate in caring for hospitalized patients with rheumatoid arthritis.

Venous compression for prevention of postthrombotic syndrome: a meta-analysis

PURPOSE To determine the effectiveness of venous compression stockings or compression bandages on the reduction of postthrombotic syndrome in patients with deep venous thrombosis. METHODS We attempted to identify all published trials in all languages identified by PubMed through June 2009. Meta-analysis was performed. RESULTS Based on 5 randomized trials of patients with deep venous thrombosis comparing treatment with venous compression to controls, mild-to-moderate postthrombotic syndrome occurred in 64 of 296 (22%) treated with venous compression, compared with 106 of 284 (37%) in controls (relative risk=0.52). Severe postthrombotic syndrome occurred in 14 of 296 (5%) treated, compared with 33 of 284 (12%) controls (relative risk=0.38). Any postthrombotic syndrome occurred in 89 of 338 (26%) treated, compared with 150 of 324 (46%) controls (relative risk=0.54). CONCLUSION Venous compression reduced the incidence of postthrombotic syndrome, particularly severe postthrombotic syndrome. Venous compression in patients with deep venous thrombosis would seem to be indicated for this purpose. There was, however, wide variation in the type of stockings used, time interval from diagnosis to application of stockings, and duration of treatment. Further investigation, therefore, is needed.