Major pulmonary embolism: review of a pathophysiologic approach to the golden hour of hemodynamically significant pulmonary embolism

Impact of delay in clinical presentation on the diagnostic management and prognosis of patients with suspected pulmonary embolism

RATIONALE

The nonspecific clinical presentation of pulmonary embolism (PE) frequently leads to delay in its diagnosis.

OBJECTIVES

This study aimed to assess the impact of delay in presentation on the diagnostic management and clinical outcome of patients with suspected PE.

METHODS

In 4,044 consecutive patients with suspected PE, patients presenting more than 7 days from the onset of symptoms were contrasted with those presenting within 7 days as regards the safety of excluding PE on the basis of a clinical decision rule combined with D-dimer testing. Patients were followed for 3 months to assess the rates of recurrent venous thromboembolism and mortality.

MEASUREMENTS AND MAIN RESULTS

A delayed presentation (presentation >7 d) was present in 754 (18.6%) of the patients. The failure rate of an unlikely clinical probability and normal D-dimer test was 0.5% (95% confidence interval [CI], 0.01-2.7) for patients with and 0.5% (95% CI, 0.2-1.2) for those without diagnostic delay. D-dimer testing yielded a sensitivity of 99% (95% CI, 96-99%) and 98% (95% CI, 97-99%) in these groups, respectively. Patients with PE with diagnostic delay more frequently had centrally located PE (41% vs. 26%; P < 0.001). The cumulative rates of recurrent venous thromboembolism (4.6% vs. 2.7%; P = 0.14) and mortality (7.6% vs. 6.6%; P = 0.31) were not different for patients with and without delayed presentation.

CONCLUSIONS

PE can be safely excluded based on a clinical decision rule and D-dimer testing in patients with a delayed clinical presentation. A delayed presentation for patients who survived acute PE was associated with a more central PE location, although this did not affect the clinical outcome at 3 months.

Mechanical ventilation and acute lung injury in emergency department patients with severe sepsis and septic shock: an observational study

OBJECTIVES

The objectives were to characterize the use of mechanical ventilation in the emergency department (ED), with respect to ventilator settings, monitoring, and titration and to determine the incidence of progression to acute lung injury (ALI) after admission, examining the influence of factors present in the ED on ALI progression.

METHODS

This was a retrospective, observational cohort study of mechanically ventilated patients with severe sepsis and septic shock (June 2005 to May 2010), presenting to an academic ED with an annual census of >95,000 patients. All patients in the study (n = 251) were analyzed for characterization of mechanical ventilation use in the ED. The primary outcome variable of interest was the incidence of ALI progression after intensive care unit (ICU) admission from the ED and risk factors present in the ED associated with this outcome. Secondary analyses included ALI present in the ED and clinical outcomes comparing all patients progressing to ALI versus no ALI. To assess predictors of progression to ALI, significant variables in univariable analyses at a p ≤ 0.10 level were candidates for inclusion in a bidirectional, stepwise, multivariable logistic regression analysis.

RESULTS

Lung-protective ventilation was used in 68 patients (27.1%) and did not differ based on ALI status. Delivered tidal volume was highly variable, with a median tidal volume delivered of 8.8 mL/kg ideal body weight (IBW; interquartile range [IQR] = 7.8 to 10.0) and a range of 5.2 to 14.6 mL/kg IBW. Sixty-nine patients (27.5%) in the entire cohort progressed to ALI after admission to the hospital, with a mean (±SD) onset of 2.1 (±1) days. Multivariable logistic regression analysis demonstrated that a higher body mass index (BMI), higher Sequential Organ Failure Assessment (SOFA) score, and ED vasopressor use were associated with progression to ALI. There was no association between ED ventilator settings and progression to ALI. Compared to patients who did not progress to ALI, patients progressing to ALI after admission from the ED had an increase in mechanical ventilator duration, vasopressor dependence, and hospital length of stay (LOS).

CONCLUSIONS

Lung-protective ventilation is uncommon in the ED, regardless of ALI status. Given the frequency of ALI in the ED, the progression shortly after ICU admission, and the clinical consequences of this syndrome, the effect of ED-based interventions aimed at reducing the sequelae of ALI should be investigated further.

ST segment elevations: always a marker of acute myocardial infarction?

Chest pain is one of the chief presenting complaints among patients attending Emergency department. The diagnosis of acute myocardial infarction may be a challenge. Various tools such as anamnesis, blood sample (with evaluation of markers of myocardial necrosis), ultrasound techniques and coronary computed tomography could be useful. However, the interpretation of electrocardiograms of these patients may be a real concern. The earliest manifestations of myocardial ischemia typically interest T waves and ST segment. Despite the high sensitivity, ST segment deviation has however poor specificity since it may be observed in many other cardiac and non-cardiac conditions. Therefore, when ST-T abnormalities are detected the physicians should take into account many other parameters (such as risk factors, symptoms and anamnesis) and all the other differential diagnoses. The aim of our review is to overview of the main conditions that may mimic a ST segment Elevation Myocardial Infarction (STEMI).

CT pulmonary angiography: increasingly diagnosing less severe pulmonary emboli

Background

It is unknown whether the observed increase in computed tomography pulmonary angiography (CTPA) utilization has resulted in increased detection of pulmonary emboli (PEs) with a less severe disease spectrum.

Methods

Trends in utilization, diagnostic yield, and disease severity were evaluated for 4,048 consecutive initial CTPAs performed in adult patients in the emergency department of a large urban academic medical center between 1/1/2004 and 10/31/2009. Transthoracic echocardiography (TTE) findings and peak serum troponin levels were evaluated to assess for the presence of PE-associated right ventricular (RV) abnormalities (dysfunction or dilatation) and myocardial injury, respectively. Statistical analyses were performed using multivariate logistic regression.

Results

268 CTPAs (6.6%) were positive for acute PE, and 3,780 (93.4%) demonstrated either no PE or chronic PE. There was a significant increase in the likelihood of undergoing CTPA per year during the study period (odds ratio [OR] 1.05, 95% confidence interval [CI] 1.04–1.07, P<0.01). There was no significant change in the likelihood of having a CTPA diagnostic of an acute PE per year (OR 1.03, 95% CI 0.95–1.11, P = 0.49). The likelihood of diagnosing a less severe PE on CTPA with no associated RV abnormalities or myocardial injury increased per year during the study period (OR 1.39, 95% CI 1.10–1.75, P = 0.01).

Conclusions

CTPA utilization has risen with no corresponding change in diagnostic yield, resulting in an increase in PE detection. There is a concurrent rise in the likelihood of diagnosing a less clinically severe spectrum of PEs.

Prognostic value of computed tomographic pulmonary angiography and the pulmonary embolism severity index in patients with acute pulmonary embolism

Pulmonary embolism is a serious and potentially fatal disorder. Pulmonary embolism risk stratification may allow early hospital discharge and outpatient treatment for low-risk patients. Also, it may prevent death by early medical intervention in high-risk groups. We evaluated objectively confirmed pulmonary embolism in 126 patients by multidetector computed tomographic pulmonary angiography at a single center from January 2008 to January 2010. The Pulmonary Severity Embolism Index (PESI), the right ventricle (RV) to left ventricle (LV) diameter (RV/LV) ratio and the vascular obstruction index (VOI) were derived from data extracted from electronic hospital records and image database. A total of six out of 96 patients (6.3%) died during follow-up. There was an association between PESI and mortality (P-value < 0.001 χ² test). PESI class I-II had a 100% negative predictive value for death in 90 days. No association was found between the RV/LV ratio, the VOI and mortality (P-value > 0.05 χ² test). Also, no association was found between the RV/LV ratio and the VOI and PESI (P-value > 0.05 χ² test). PESI is an accurate tool for pulmonary embolism prognostic stratification. It safely discriminates low-risk from high-risk patients regarding death outcome. We were unable to demonstrate an association between image scores and mortality.

Mechanical breakdown and thrombolysis in subacute massive pulmonary embolism: A prospective trial

AIM: To assess role of combined modality of mechanical fragmentation and intralesional thrombolysis in patients with massive pulmonary embolism presenting subacutely.

METHODS: Eight of 70 patients presenting in tertiary care centre of North India with massive pulmonary embolism within 4 years had subacute presentation (symptom onset more than 2 wk). These patients were subjected to pulmonary angiography with intention to treat basis via mechanical breakdown and intra lesional thrombolysis. Mechanical breakdown of embolus was accomplished with 5-F multipurpose catheter to re-establish flow, followed by intralesional infusion of urokinase (4400 IU/kg over 10 min followed by 4400 IU/kg per hour over 24 h).

RESULTS: Eight patients, mean age 47.77 ± 12.20 years presented with subacute pulmonary embolism (mean duration of symptoms 2.4 wk). At presentation, mean heart rate, shock index, miller score and mean pulmonary pressures were 101.5 ± 15.2/min, 0.995 ± 0.156, 23.87 ± 3.76 and 37.62 ± 6.67 mmHg which reduced to 91.5 ± 12.2/min (P = 0.0325), 0.789 ± 0.139 (P = 0.0019), 5.87 ± 1.73 (P = 0.0000004) and 27.75 ± 8.66 mmHg (P = 0.0003) post procedurally. Mean BP improved from 80.00 ± 3.09 mmHg to 90.58 ± 9.13 mmHg (P = 0.0100) post procedurally. Minor complications in the form of local hematoma-minor hematoma in 1 (12.5%), and pseudoaneurysm (due to femoral artery puncture) in 1 (12.5 %) patient were seen. At 30 d and 6 mo follow up survival rate was 100% and all the patients were asymptomatic and in New York Heart Association class 1.

CONCLUSION: Combined modality of mechanical fragmentation and intralesional thrombolysis appears to be a promising alternative to high risk surgical procedures in patients with subacute massive pulmonary embolism.

Risk factors associated with the occurrence of silent pulmonary embolism in patients with deep venous thrombosis of the lower limb

OBJECTIVE

The aim of our study is to investigate the prevalence of silent pulmonary embolism in patients with deep venous thrombosis in the lower limbs and to evaluate the associated risk factors.

METHODS

A total of 322 patients with acute deep venous thrombosis confirmed by CT venography or Doppler ultrasonography were studied. The diagnosis of silent pulmonary embolism was established by computed tomography pulmonary arteriography (CTPA). The association between covariates and the prevalence of silent pulmonary embolism in patients with deep venous thrombosis in lower limbs were assessed using chi-square test and multivariable regression.

RESULTS

The incidence of silent pulmonary embolism was 33.5% (108 in 322 patients) in all patients with deep venous thrombosis in lower limbs. Chi-square test showed male gender, the right lower limb, proximal location of the thrombus, unprovoked venous thrombosis and coexisting heart diseases were related to a higher incidence of silent pulmonary embolism in patients with deep venous thrombosis in lower limbs. The multivariate regression analysis confirmed that the risk factors associated with silent pulmonary embolism in deep venous thrombosis patients included the right side and proximal location of the thrombus (odds ratio: 2.023, 95% CI: 1.215-3.368; odds ratio: 3.610, 95% CI: 1.772-7.354), unprovoked venous thrombosis (odds ratio: 2.037, 95% CI: 1.188-3.493), coexisting heart diseases (odds ratio: 4.507, 95% CI: 2.667-7.618).

CONCLUSION

Silent pulmonary embolism occurred frequently in patients with deep venous thrombosis in lower limbs. The right side, the proximal location of the thrombus, unprovoked venous thrombosis and coexisting heart diseases increased the risk for the occurrence of silent pulmonary embolism.

Hestia criteria can safely select patients with pulmonary embolism for outpatient treatment irrespective of right ventricular function

BACKGROUND

There has been debate over how patients with pulmonary embolism (PE) can be safely selected for outpatient treatment.

OBJECTIVES

To compare the Hestia criteria with the European Society of Cardiology (ESC) criteria for selecting low-risk patients with PE for outpatient treatment.

METHODS

From 2008 to 2010, 496 patients with acute, symptomatic PE were screened and 275 treated at home and 221 treated in the hospital according to the Hestia Study protocol. The Hestia criteria were used to select patients for outpatient treatment. Right and left ventricular (RV and LV) diameters were measured on computed tomography images. RV dysfunction was defined as an RV/LV ratio > 1.0. Patients were classified according to the ESC criteria into low, intermediate and high-risk groups, based on blood pressure and RV dysfunction. During 3 months follow-up adverse events were scored.

RESULTS

Adverse events occurred in 22 patients (4.5%) treated in the hospital vs. none of the patients treated at home (P < 0.001). Sensitivity and negative predictive value for adverse outcome were 100% for the Hestia criteria and 96% and 99% for the ESC criteria, respectively. Of the patients treated at home according to the Hestia criteria, 35% were normotensive but had RV dysfunction and were classified as intermediate risk according to the ESC criteria. No adverse events happened in these patients treated at home.

CONCLUSIONS

Clinical criteria, such as the Hestia criteria, could be helpful in selecting patients, including those with RV dysfunction who have a low risk of adverse clinical outcome and could be candidates for outpatient treatment.

Endovascular management of massive pulmonary embolism with clot fragmentation and suction

Massive pulmonary embolism with right ventricular dysfunction may be treated with thrombolysis, embolectomy, or percutaneous mechanical thrombectomy. This study describes our experience with two patients that had massive pulmonary embolism and were treated with percutaneous mechanical thrombectomy and reports on the mid-term results of this procedure. A 28-year-old man and a 70-year-old woman were diagnosed with deep venous thrombosis and massive pulmonary embolism. They first had lower limb edema followed by sudden onset of dyspnea. Their physical examination revealed edema, tachypnea, chest discomfort and jugular turgescence. Both needed to receive oxygen using a nasal cannula. Doppler ultrasound, echocardiography, and computed tomography angiography were used to establish the diagnoses. Patients underwent percutaneous mechanical thrombectomy using the Aspirex® system (Straub Medical), and their clinical condition and imaging study findings improved substantially. At mid-term follow-up, patient conditions were improving satisfactorily.

Factor V leiden thrombophilia in a female collegiate soccer athlete: a case report

OBJECTIVE

To raise awareness among health care providers caring for an active population to an uncommon genetic mutation that increases the risk for a potentially fatal venous thromboembolism.

BACKGROUND

A 19-year-old previously healthy female collegiate soccer athlete complained of coughing and progressively decreased exercise tolerance, which were attributed to a recent illness and lack of sleep. Later that evening, she complained of dyspnea and pleuritic pain and was referred to the emergency department. Bilateral pulmonary emboli were identified with computed tomography, and a hypercoagulable panel revealed that the patient was heterozygous for the factor V Leiden mutation.

DIFFERENTIAL DIAGNOSIS

Pneumonia, pneumothorax, pericarditis, pleuritis, gastroesophageal reflux disease, pulmonary embolism.

TREATMENT

Intravenous heparin therapy was initiated immediately in the emergency department. This was followed by inpatient anticoagulant therapy for 5 days and outpatient anticoagulant therapy for an additional 12 months. During this time, the patient was unable to participate in soccer drills or return to competition and was limited to conditioning activities due to the risk of increased bleeding time.

UNIQUENESS

Documented cases of pulmonary embolism in a young athletic population are rare and are usually associated with genetic risk factors. Factor V Leiden is a relatively uncommon genetic mutation that dramatically increases the risk for venous thromboembolism. Although the fatality rate in this population is low, fatality is preventable if the condition is recognized early and managed properly.

CONCLUSIONS

Athletes should be encouraged to communicate with their athletic trainers regarding any changes in health status or medication usage. When an athlete presents with nonspecific symptoms such as dyspnea and chest pain, athletic trainers should consider the possibility of pulmonary embolism. A high degree of suspicion results in early diagnosis and treatment and may prevent a fatal event.

Evaluation of right ventricular systolic function by the analysis of tricuspid annular motion in patients with acute pulmonary embolism

Background

Measurement of right ventricular (RV) systolic function is important for patients with acute pulmonary embolism (PE). However, assessment of RV function is a challenge due to its complex anatomy. We measured RV systolic function with analysis of tricuspid annular motion in acute PE patients.

Methods

From August 2007 to May 2011, all consecutive PE patients were prospectively included. Tricuspid annular motion was analyzed with tricuspid annular plane systolic excursion (TAPSE) and tricuspid annular systolic velocity (TASV).

Results

We analyzed total 50 patients (38 females, 68 ± 14 years). Mean RV fractional area change (RVFAC) was 26.2 ± 10.8%; RV Tei index 0.78 ± 0.35; TR Vmax 3.8 ± 0.5 m/sec; pulmonary vascular resistance (PVR) 3.5 ± 1.2 WU. TAPSE was 16 ± 4 mm and TASV was 11.7 ± 4.0 cm/sec. TAPSE showed significant correlations with RVFAC (r = 0.841, p < 0.001), RV Tei index (r = -0.347, p = 0.018), Log B-type natriuretic peptide (BNP) (r = -0.634, p < 0.001) and PVR (r = -0.635, p < 0.001). TASV also revealed significant correlations with RVFAC (r = 0.605, p < 0.001), RV Tei index (r = -0.380, p = 0.009), LogBNP (r = -0.477, p = 0.001) and PVR (r = -0.483, p = 0.001). The best cutoff of TAPSE for detection of RV systolic dysfunction (defined as RVFAC < 35%) was 1.75 cm [Areas under the curve (AUC) = 0.96, p < 0.001] with a sensitivity of 87% and specificity 91%. The best cutoff for TASV was 13.8 cm/sec (AUC = 0.90, p < 0.001), sensitivity 86% and specificity 78%. However, there was no statistical significance in the detection of RV dysfunction (difference = 0.07, 95% CI = -0.21-0.17, p = 0.130) between TAPSE and TASV.

Conclusion

TAPSE and TASV showed significant correlations with conventional echocardiographic parameters of RV function and LogBNP value. These values can be used to detect RV systolic dysfunction more easily in patients with acute PE.

Emergency Department vancomycin use: dosing practices and associated outcomes

BACKGROUND

Emergency Department (ED) dosing of vancomycin and its effect on outcomes has not been examined.

STUDY OBJECTIVE

To describe current vancomycin dosing practices for ED patients, focusing on patient factors associated with administration, dosing accuracy based on patient body weight, and clinical outcomes.

METHODS

Single-center, retrospective cohort study of vancomycin administered in the ED over 18 months in an academic, tertiary care ED. Data were collected on 4656 patients. Data were analyzed using a generalized estimating equations model to account for multiple doses being administered to the same patient.

RESULTS

The ED dose was continued, unchanged, in 2560 admitted patients (83.8%). The correct dose was given 980 times (22.1%), 3143 doses (70.7%) were underdosed, and 318 were overdosed (7.2%). Increasing weight was associated with underdosing (adjusted odds ratio 1.52 per 10 kg body weight, p < 0.001). Patients who received doses of vancomycin > 20 mg/kg had longer hospital length of stay (p = 0.005); were more likely to spend ≥ 3 days in the hospital (odds ratio [OR] 1.49; 95% confidence interval [CI] 1.12-1.98, p = 0.006); and more likely to die (OR 1.88; 95% CI 1.22-2.90, p = 0.004).

CONCLUSION

In this largest study to date examining ED vancomycin dosing, vancomycin was commonly given. Dosing outside the recommended range was frequent, and especially prevalent in patients with a higher body weight. The ED dose of vancomycin was frequently continued as an inpatient, regardless of dosing accuracy. There is significant room for improvement in dosing accuracy and indication. Vancomycin dosing in the ED may also affect clinical outcomes.

Management of massive and nonmassive pulmonary embolism

Massive pulmonary embolism (PE) is characterized by systemic hypotension (defined as a systolic arterial pressure < 90 mm Hg or a drop in systolic arterial pressure of at least 40 mm Hg for at least 15 min which is not caused by new onset arrhythmias) or shock (manifested by evidence of tissue hypoperfusion and hypoxia, including an altered level of consciousness, oliguria, or cool, clammy extremities). Massive pulmonary embolism has a high mortality rate despite advances in diagnosis and therapy. A subgroup of patients with nonmassive PE who are hemodynamically stable but with right ventricular (RV) dysfunction or hypokinesis confirmed by echocardiography is classified as submassive PE. Their prognosis is different from that of others with non-massive PE and normal RV function. This article attempts to review the evidence-based risk stratification, diagnosis, initial stabilization, and management of massive and nonmassive pulmonary embolism.

Short-term mortality in acute pulmonary embolism: clot burden and signs of right heart dysfunction at CT pulmonary angiography

PURPOSE

To assess the correlation between volumetric measurements of clot, semiquantitative clot burden indexes, and signs of right heart dysfunction at computed tomographic (CT) pulmonary angiography in patients with acute pulmonary embolism (PE) and to determine whether clot burden and signs of right heart dysfunction are associated with short-term mortality.

MATERIALS AND METHODS

This retrospective study was institutional review board approved and HIPAA compliant. CT pulmonary angiographic studies (January 2007 through December 2007) with findings positive for PE were retrieved. Two readers evaluated signs of right heart dysfunction at CT pulmonary angiography, measured clot volume using a dedicated software program, and assessed clot burden using semiquantitative scores (Qanadli and Mastora). Spearman rank coefficient was used to investigate correlation between clot burden measures and signs of right heart dysfunction. Uni- and multivariate analyses were used to test association between CT pulmonary angiographic findings and short-term mortality.

RESULTS

A total of 635 CT pulmonary angiographic studies from 635 patients (304 men, 331 women; mean age, 59 years) were included; 39 (6%) patients died within 30 days. Clot volume was strongly correlated with Qanadli score (ρ=0.841, P<.01) and Mastora score (ρ=0.863, P<.01) and moderately correlated (ρ=0.378, P<.01) with the ratio of right ventricle diameter to left ventricle diameter (RV/LV ratio). Among the pulmonary angiographic signs, only increase in RV/LV ratio (cut-off value, 1.0) was independently associated with short-term mortality in multivariate analysis.

CONCLUSION

Clot volume strongly correlated with semiquantitative CT scores of clot burden, and greater clot volume was associated with higher incidence of right heart dilatation. Increase in RV/LV ratio was associated with short-term mortality; however, measures of clot burden were not.

Statistical methods for predicting mortality in patients diagnosed with acute pulmonary embolism

RATIONALE AND OBJECTIVES

Risk stratification in pulmonary embolism (PE) guides patient management. The purpose of this study was to develop and test novel mortality risk prediction models for subjects with acute PE diagnosed using computed tomographic pulmonary angiography in a large cohort with comprehensive clinical data.

MATERIALS AND METHODS

Retrospective analyses of 1596 consecutive subjects diagnosed with acute PE from a single, large, urban teaching hospital included two modern statistical methods to predict survival in patients with acute PE. Landmark analysis was used for 90-day mortality. Adaptive least absolute shrinkage and selection operator (aLASSO), a penalization method, was used to select variables important for prediction and to estimate model coefficients. Receiver-operating characteristic analysis was used to evaluate the resulting prediction rules.

RESULTS

Using 30-day all-cause mortality outcome, three of the 16 clinical risk factors (the presence of a known malignancy, coronary artery disease, and increased age) were associated with high risk, while subjects treated with anticoagulation had lower risk. For 90-day landmark mortality, subjects with recent operations had a lower risk for death. Both prediction rules developed using aLASSO performed well compared to standard logistic regression.

CONCLUSIONS

The aLASSO regression approach combined with landmark analysis provides a novel tool for large patient populations and can be applied for clinical risk stratification among subjects diagnosed with acute PE. After positive results on computed tomographic pulmonary angiography, the presence of a known malignancy, coronary artery disease, and advanced age increase 30-day mortality. Additional risk stratification can be simplified with these methods, and future work will place imaging-based prediction of mortality in perspective with other clinical data.

Successful thrombolysis in postoperative patients with acute massive pulmonary embolism

PURPOSE

The standard medical management for patients with acute massive pulmonary embolism (MPE) is systemic thrombolysis. However, it is generally thought that recent surgeries are a contraindication to thrombolytic therapy. In this study, we evaluated the efficacy and safety of systemic thrombolysis for postoperative patients with acute MPE and assessed the risk of bleeding.

METHODS

A retrospective review was performed on 21 postoperative patients with MPE in a timeframe of five years (from 2005 to 2010). The criteria for study inclusion were postoperative patients who received systemic thrombolysis for confirmed acute MPE within three weeks after surgery.

RESULTS

Seventeen postoperative patients, including men (12) and women (five) aged 53±16 (range 23-71) years, were treated with systemic thrombolysis. Significant haemodynamic improvement (shock index<0.9) was observed in 16 of 17 cases (94%). The remaining patient (6%) died of cardiac arrest within 24h. No major bleeding complication was observed. Sixteen patients survived and remained stable for 34±16 (range 11-52) days until hospital discharge.

CONCLUSION

Recent surgery is not an absolute contraindication to systemic thrombolysis. Further, to obtain a successful outcome, it is crucial to exclude patients who have received neurosurgical operations or those with other contraindications to thrombolytic therapy.

Estimation of endothelin-mediated vasoconstriction in acute pulmonary thromboembolism

We aimed to investigate the role of endothelin-mediated vasoconstriction following acute pulmonary thromboembolism (APTE). Thirteen anesthetized piglets (~25 kg) were ventilated with 0 PEEP. Cardiac output (Qt) and wedge pressure (Pw) were measured by a Swan Ganz catheter, along with arterial and venous blood gases. APTE was induced by autologous blood clots (~0.8 g/kg, 12-16 pieces) via a jugular venous catheter at time = 0 minutes until the mean pulmonary arterial pressure (Ppa) was about 2.5 times the baseline at 30 minutes. Eight control animals (Group 1) received only normal saline afterward, while the remaining five (Group 2) received at time = 40-minute saline plus Tezosentan, a nonspecific endothelin antagonist. The drug was initially given as an intravenous bolus (10 mg/kg), followed by an infusion (2 mg/min) until the end of the experiment at 2 hours. Hemodynamic data were measured before APTE and then at 30-minute intervals. Pulmonary vascular resistance index (PVRI) was calculated as (Ppa-Pw)/CI, where CI was cardiac index or Qt/W (body weight). Fluorescent microspheres (FMS) were used to mark regional blood flows and ventilation for cluster analysis. PVRI acutely increased within minutes and remained high despite some recovery over time. With Tezosentan treatment, the results showed that endothelin-mediated vasoconstriction persisted significantly up to 2 hours and accounted for about 25% of the increase in PVRI while clot obstruction accounted for the remaining 75%. CI remained relatively constant throughout. Tezosentan also affected PVRI indirectly by mitigating the shift of regional blood flow back to the embolized areas over time, possibly by attenuating vasoconstriction in the nonembolized areas. We conclude that following APTE, although the increased PVRI is mostly due to mechanical embolic obstruction, secondary factors such as vasoconstriction and pattern of regional blood flow over time also play important roles.

Blood flow redistribution and ventilation-perfusion mismatch during embolic pulmonary arterial occlusion

Acute pulmonary embolism causes redistribution of blood in the lung, which impairs ventilation/perfusion matching and gas exchange and can elevate pulmonary arterial pressure (PAP) by increasing pulmonary vascular resistance (PVR). An anatomically-based multi-scale model of the human pulmonary circulation was used to simulate pre- and post-occlusion flow, to study blood flow redistribution in the presence of an embolus, and to evaluate whether reduction in perfused vascular bed is sufficient to increase PAP to hypertensive levels, or whether other vasoconstrictive mechanisms are necessary. A model of oxygen transfer from air to blood was included to assess the impact of vascular occlusion on oxygen exchange. Emboli of 5, 7, and 10 mm radius were introduced to occlude increasing proportions of the vasculature. Blood flow redistribution was calculated after arterial occlusion, giving predictions of PAP, PVR, flow redistribution, and micro-circulatory flow dynamics. Because of the large flow reserve capacity (via both capillary recruitment and distension), approximately 55% of the vasculature was occluded before PAP reached clinically significant levels indicative of hypertension. In contrast, model predictions showed that even relatively low levels of occlusion could cause localized oxygen deficit. Flow preferentially redistributed to gravitationally non-dependent regions regardless of occlusion location, due to the greater potential for capillary recruitment in this region. Red blood cell transit times decreased below the minimum time for oxygen saturation (<0.25 s) and capillary pressures became high enough to initiate cell damage (which may result in edema) only after ~80% of the lung was occluded.

CT findings and long-term mortality after pulmonary embolism

OBJECTIVE

The utility of CT findings in predicting long-term mortality in patients with acute pulmonary embolism (PE) is unknown. The purpose of this study is to retrospectively determine whether three CT findings--increased embolic burden, interventricular septal bowing toward the left ventricle, and right ventricle-to-left ventricle (RV/LV) diameter ratio greater than 1--are independent predictors of long-term all-cause mortality after acute PE.

MATERIALS AND METHODS

A total of 1105 patients (47% female; mean age, 63 ± 16 years) with CT scans positive for PE from January 1, 1997, to December 31, 2002, were included. Scans were independently interpreted by two observers, with a third independent observer reviewing discrepant cases. CT findings and clinical information were compared with all-cause mortality using univariate and multivariate logistic regression analyses.

RESULTS

The median duration of survival was 6.2 years following acute PE, with estimated 10-year survival of 37.4%. CT-derived embolic burden was associated with a very small decrease in long-term all-cause mortality in both univariate (hazard ratio [HR], 0.97; p < 0.001) and multivariate (HR, 0.97; p < 0.001) analyses. Interventricular septal bowing and RV/LV diameter ratio were not significantly associated with long-term all-cause mortality.

CONCLUSION

CT findings are not predictive of decreased long-term survival after acute PE.

Diagnosis of pulmonary embolism: Advances and pitfalls

The signs and symptoms of patients with pulmonary embolism (PE) form a wide spectrum and considerably overlap with other cardiopulmonary diseases. Timely recognizing of this disease therefore remains challenging, but is of vital importance to avoid PE-related morbidity and mortality. To aid and standardize the initial diagnostic approach of patients with suspected PE, clinical probability rules have been developed and simplified for use in clinical practice. It has been demonstrated by clinical outcome studies that it is safe and of high clinical utility to exclude PE on the basis of an unlikely clinical probability and a normal D-dimer test result. For the remaining patients with suspected PE, imaging tests are required. The introduction of multi-detector computed tomographic pulmonary angiography (MD-CTA) has significantly improved the detection of PE, and this test is now regarded as the imaging test of first choice. This review will focus on recent advances and pitfalls that remain in the diagnostic work-up of patients with suspected acute PE.

Right ventricular responses to massive and submassive pulmonary embolism

It is critically important to quickly recognize and treat acute pulmonary embolism (PE). Submassive and massive PEs are associated with right ventricular (RV) dysfunction and may culminate in RV failure, cardiac arrest, and death. A rapid and coordinated diagnostic and management approach can maximize success and save lives.

Pulmonary embolism in the emergency department: a Singaporean nursing case review

INTRODUCTION

The presentation of pulmonary embolism to the emergency department (ED) can prove challenging because of the myriad of potential disease processes that mimic its signs and symptoms. The incidence of pulmonary embolism and indeed the mortality associated with it is relatively high. Early diagnosis and treatment is crucial in off-setting the potential deleterious effects associated with this condition. The aim of this article is to present a nursing case review of a patient presenting to the ED with a diagnosis of pulmonary embolism.

METHOD

We chose to use a case review to highlight the nursing and medical care that was provided for a patient who presented to the emergency department acutely with dyspnoea, chest pain and pyrexia. The use of case reviews are useful in reporting unusual or rare cases and this format is typically seen more in medicine than in nursing. They can naturally take one of two formats-a single case report or a series of case reports; in this case we opted to report on a single case.

DISCUSSION

The gentleman in question was an ambulance admission to the ED with a three day history of chest pain, shortness of breath and one episode of syncope which brought him to the ED. Over the course of his admission a variety of treatment modalities were used successfully to alleviate the problem. More notable from a nursing perspective was the use of diagnostic tools as an interpretation to guide his care and provide a platform from which a deeper understanding and appreciation of the intricacies the critically ill patient often presents.

CONCLUSION

We found the use of case review very enlightening in understanding the disease process and the decision-making that accompanies this. Whilst our patient was successfully rehabilitated home, we learnt a lot from the experience which has been most beneficial in supporting our understanding of pulmonary embolism.

Diagnostic approach to deep venous thrombosis and pulmonary embolism in the critical care setting

Considerable progress has been made during the last 30 years in the prevention, diagnosis, and therapy of venous thromboembolism. This article discusses the epidemiology, pathophysiology, and clinical presentation of the disease as well as the diagnostic uncertainty that exists in the critical care setting. Diagnostic approaches for deep venous thrombosis and pulmonary embolism are considered, including clinical prediction rules, D-dimer, contrast venography, duplex ultrasonography, computed tomographic angiography and venography, magnetic resonance imaging, ventilation–perfusion scanning, chest radiograph, arterial blood gases, electrocardiography, and echocardiography.

Natural history of venous thromboembolism

Venous thromboembolism (VTE) originates in systemic venous thrombosis and has different etiological mechanisms and natural history from arterial thrombosis. VTE typically originates as deep venous thrombosis in a lower extremity, where it may give rise to acute symptoms “upstream” from the obstructed vein, result in pulmonary embolism, and/or cause chronic venous obstruction. Pulmonary embolism may result in acute respiratory symptoms, cardiovascular collapse and, uncommonly, may also cause chronic disease.

Prognostic value of perfusion defect volume at dual energy CTA in patients with pulmonary embolism: correlation with CTA obstruction scores, CT parameters of right ventricular dysfunction and adverse clinical outcome

PURPOSE

To investigate the prognostic value of perfusion defect volume (PDvol) at dual-energy-CT-angiography (DE-CTA) in patients with acute pulmonary embolism (PE) by correlating PDvol with CTA-obstruction-scores (OS), CT parameters of right-ventricular-dysfunction (RVD), and adverse-clinical-outcome.

MATERIALS AND METHODS

DE-CTA of 60 patients (mean age: 65±14.4 years) with PE were analyzed. Iodine maps were generated, and normalized PDvol--defined as volume of perfusion defects/total lung volume--was quantified. Furthermore, established prognostic parameters (Qanadli and Mastora-OS, and CT parameters of RVD) were obtained. CT parameters of RVD--namely the right ventricle/left ventricle (RV/LV) diameter ratio measured on transverse sections (RV/LVtrans), four-chamber views (RV/LV4ch), and RV/LV volume ratios (RV/LVvol)--were assessed. PDvol was correlated with OS, CT parameters of RVD and adverse clinical outcome (defined as the need for intensive care treatment or death).

RESULTS

10 of 60 patients with PE experienced adverse clinical outcome. Patients with adverse clinical outcome showed significantly higher PDvol (35±11% vs. 23±10%, p=0.002), RV/LV ratios (RV/LV4ch 1.46±0.32 vs. 1.18±0.26, p=0.005; RV/LVvol 2.25±1.33 vs. 1.19±0.56, p=0.002) and higher Mastora global scores (52 vs. 13, p=0.02) compared to those without adverse clinical outcome. A weak correlation was observed between PDvol and the Mastora global score (r=0.5; p=0.0003), as well as between PDvol and RV/LV4Ch (r=0.432, p=0.0006). No correlation was found between PDvol and the Qanadli score or the remainder of the RVD-CT parameters.

CONCLUSION

The extent of perfusion defects as assessed by DE-CTA correlates with adverse clinical outcome in patients with PE. Therefore, volumetric quantification of perfusion defects at DE-CTA allows the identification of low-risk patients who do not require intensified monitoring and treatment.

Massive pulmonary embolism: surgical embolectomy versus thrombolytic therapy--should surgical indications be revisited?

OBJECTIVES

The treatment of massive pulmonary embolism (PE) is a matter of debate. We present our institutional experience of patients suffering from massive PE with the aim of comparing the early results, the outcome and quality of life (QoL) between patients primarily assigned to either pulmonary surgical embolectomy (SE) or thrombolytic therapy (TL). A subgroup of patients (TS) with failed responses to TL requiring SE was separately analysed.

METHODS

All consecutive patients (January 2001-December 2007) with computed tomography (CT)-scan-confirmed massive bilateral central or paracentral PE were reviewed. All clinical data were retrieved from our patients' registry and completed by the evaluation of the CT-scan-derived right ventricle/left ventricle ratio (RV/LV ratio). Follow-up focused on clinical outcome and QoL was obtained.

RESULTS

Eighty patients were analysed including 28 SE (35%) and 52 TL (65%), of whom 11 (21%) required TS. Demographics and preoperative characteristics were similar between SE and TL. Analysis of the RV/LV ratio revealed a ratio of 1.66 for SE and 1.44 for TL. The early mortality rate was not significantly different between the two groups (SE: 3.6% versus TL: 13.5%), whereas early mortality was 27% in those patients treated initially with thrombolysis and subsequently requiring SE (TS-group). Severe bleeding complications were lower in the SE-group (3.6% versus 26.5% P = 0.013). Intracerebral bleeding rates and neurological events were not statistically different. After a mean follow-up of 63 ± 21 months, the mortality rate was 17.9% in the SE-group and 23.1% in the TL-group.

CONCLUSIONS

SE is an excellent treatment option in massive PE with comparable early mortality rates and significantly less bleeding complications than TL. Patients having surgery after inefficient thrombolysis have the worst early outcome. The RV/LV CT-scan ratio might serve as a predictor to differentiate patients, who could profit from direct surgical intervention than thrombolytic treatment attempts. Further studies are required to confirm these results.

Antithrombotic therapy for VTE disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

This article addresses the treatment of VTE disease.

METHODS

We generated strong (Grade 1) and weak (Grade 2) recommendations based on high-quality (Grade A), moderate-quality (Grade B), and low-quality (Grade C) evidence.

RESULTS

For acute DVT or pulmonary embolism (PE), we recommend initial parenteral anticoagulant therapy (Grade 1B) or anticoagulation with rivaroxaban. We suggest low-molecular-weight heparin (LMWH) or fondaparinux over IV unfractionated heparin (Grade 2C) or subcutaneous unfractionated heparin (Grade 2B). We suggest thrombolytic therapy for PE with hypotension (Grade 2C). For proximal DVT or PE, we recommend treatment of 3 months over shorter periods (Grade 1B). For a first proximal DVT or PE that is provoked by surgery or by a nonsurgical transient risk factor, we recommend 3 months of therapy (Grade 1B; Grade 2B if provoked by a nonsurgical risk factor and low or moderate bleeding risk); that is unprovoked, we suggest extended therapy if bleeding risk is low or moderate (Grade 2B) and recommend 3 months of therapy if bleeding risk is high (Grade 1B); and that is associated with active cancer, we recommend extended therapy (Grade 1B; Grade 2B if high bleeding risk) and suggest LMWH over vitamin K antagonists (Grade 2B). We suggest vitamin K antagonists or LMWH over dabigatran or rivaroxaban (Grade 2B). We suggest compression stockings to prevent the postthrombotic syndrome (Grade 2B). For extensive superficial vein thrombosis, we suggest prophylactic-dose fondaparinux or LMWH over no anticoagulation (Grade 2B), and suggest fondaparinux over LMWH (Grade 2C).

CONCLUSION

Strong recommendations apply to most patients, whereas weak recommendations are sensitive to differences among patients, including their preferences.

Intramedullary nailing of femoral shaft fractures in polytraumatized patients. a longitudinal, prospective and observational study of the procedure-related impact on cardiopulmonary- and inflammatory responses

BACKGROUND

Early intramedullary nailing (IMN) of long bone fractures in severely injured patients has been evaluated as beneficial, but has also been associated with increased inflammation, multi organ failure (MOF) and morbidity. This study was initiated to evaluate the impact of primary femoral IMN on coagulation-, fibrinolysis-, inflammatory- and cardiopulmonary responses in polytraumatized patients.

METHODS

Twelve adult polytraumatized patients with femoral shaft fractures were included. Serial blood samples were collected to evaluate coagulation-, fibrinolytic-, and cytokine activation in arterial blood. A flow-directed pulmonary artery (PA) catheter was inserted prior to IMN. Cardiopulmonary function parameters were recorded peri- and postoperatively. The clinical course of the patients and complications were monitored and recorded daily.

RESULTS

Mean Injury Severity Score (ISS) was 31 ± 2.6. No procedure-related effect of the primary IMN on coagulation- and fibrinolysis activation was evident. Tumor necrosis factor alpha (TNF-α) increased significantly from 6 hours post procedure to peak levels on the third postoperative day. Interleukin-6 (IL-6) increased from the first to the third postoperative day. Interleukin-10 (IL-10) peaked on the first postoperative day. A procedure-related transient hemodynamic response was observed on indexed pulmonary vascular resistance (PVRI) two hours post procedure. 11/12 patients developed systemic inflammatory response syndrome (SIRS), 7/12 pneumonia, 3/12 acute lung injury (ALI), 3/12 adult respiratory distress syndrome (ARDS), 3/12 sepsis, 0/12 wound infection.

CONCLUSION

In the polytraumatized patients with femoral shaft fractures operated with primary IMN we observed a substantial response related to the initial trauma. We could not demonstrate any major additional IMN-related impact on the inflammatory responses or on the cardiopulmonary function parameters. These results have to be interpreted carefully due to the relatively few patients included.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00981877.

Rheolytic Thrombectomy with or without Adjunctive Indwelling Pharmacolysis in Patients Presenting with Acute Pulmonary Embolism Presenting with Right Heart Strain and/or Pulseless Electrical Activity

Purpose. To evaluate the safety and efficacy of the Possis rheolytic thrombectomy with or without indwelling catheter-directed pharmacolysis for the treatment of massive pulmonary embolus in patients presenting with right heart strain and/or a pulseless electrical activity (PEA). Materials and Methods. Retrospective review of patients undergoing pulmonary pharmacolysis was performed (07/2004-06/2009). Pre- and posttreatment Miller index scoring weres calculated and compared. Patients were evaluated for tPA doses, ICU stay, hospital stay, and survival by Kaplan-Meier analysis. Results. 11 patients with massive PE were found, with 10/11 presenting with a Miller score of >17 (range: 16-27, mean: 23.2). CTPA and/or echocardiographic evidence of right heart strain was found in 10/11 patients. 3 (27%) patients presented with a PEA event. Two (18%) patients had a contraindication to pharmacolysis and were treated with mechanical thrombectomy alone. The intraprocedural mortality was 9% (n = 1/11). Of the 10 patients who survived the initial treatment, 7 patients underwent standard mechanical thrombectomy initially, while 5 received power pulse spray mechanical thrombectomy. Eight of these 10 patients underwent adjunctive indwelling catheter-directed thrombolysis. The mean catheter-directed infusion duration was 18 hours (range of 12-26 hours). The average intraprocedural, infusion, and total doses of tPA were 7 mg, 19.7 mg, and 26.7 mg, respectively. There was a 91% (10/11) technical success rate. The failure was the single mortality. Average reduction in Miller score was 9.5 or 41% (P = 0.009), obstructive index of 6.4 or 47% (P = 0.03), and perfusion index of 2.7 or 28% (P = 0.05). Average ICU and hospital stay were 7.4 days (range 2-27 days) and 21.3 days (range 6-60 days), respectively. Intent to treat survival was 90% at 6, 12, and 18 months. Conclusion. Rheolytic thrombectomy with or without adjunctive catheter-directed thrombolysis provides a safe and effective method for treatment of acute PE in patients who present with right heart strain and/or a PEA event.

Endovascular therapy for acute pulmonary embolism

Acute pulmonary embolism (PE) is the third most common cause of death among hospitalized patients. Treatment escalation beyond anticoagulation therapy is necessary in patients with massive PE (defined by hemodynamic shock) as well as in many patients with submassive PE (defined by right ventricular strain). The best current evidence suggests that modern catheter-directed therapy to achieve rapid central clot debulking should be considered as an early or first-line treatment option for patients with acute massive PE; and emerging evidence suggests a catheter-directed thrombolytic infusion should be considered as adjunctive therapy for many patients with acute submassive PE. This article reviews the current approach to endovascular therapy for acute PE in the context of appropriate diagnosis, risk stratification, and management of acute massive and acute submassive PE.