DVT Prophylaxis and DVT Prophylaxis and Pulmonary Embolism in Pulmonary Embolism in

Surgical PatientsSurgical Patients

Bradley J. Phillips, MDBradley J. Phillips, MD

Burn-Trauma-ICUAdults & Pediatrics

Pulmonary EmbolismPulmonary Embolism

► PathogenesisPathogenesis Vichow’s triadVichow’s triad Clot dislodgementClot dislodgement Release of vasoactive substancesRelease of vasoactive substances

►increased pulmonary vascular resistanceincreased pulmonary vascular resistance►bronchoconstrictionbronchoconstriction

► EpidemiologyEpidemiology Incidence = 1/1000 per yearIncidence = 1/1000 per year Mortality (1 year) = 15 %Mortality (1 year) = 15 %

Risk Factors - AcquiredRisk Factors - Acquired

► MedicalMedical Prior PEPrior PE Age > 40Age > 40 ObesityObesity MalignancyMalignancy CHFCHF CVACVA Nephrotic SyndromeNephrotic Syndrome EstrogenEstrogen PregnancyPregnancy

► SurgicalSurgical General anesthesia General anesthesia

> 30 minutes> 30 minutes Hip arthroplastyHip arthroplasty Knee arthroplastyKnee arthroplasty Major traumaMajor trauma Spinal Cord InjurySpinal Cord Injury Open prostatectomyOpen prostatectomy Neurosurgical Neurosurgical

proceduresprocedures

Risk Factors - HereditaryRisk Factors - Hereditary

► Protein C deficiencyProtein C deficiency► Protein S deficiencyProtein S deficiency► Antithrombin III deficiencyAntithrombin III deficiency► Factor V leiden mutationFactor V leiden mutation

Risk Assessment Profile Risk Assessment Profile ► Significant risk in trauma patientsSignificant risk in trauma patients► Risk assessment profile of Risk assessment profile of

thromboembolism (RAPT) by Greenfieldthromboembolism (RAPT) by Greenfield 5 or more (out of 14) increases risk 3 times5 or more (out of 14) increases risk 3 times

►Underlying condition Underlying condition Obese, malignancy, hx of thromboembolismObese, malignancy, hx of thromboembolism

►Iatrogenic factorsIatrogenic factors CVL, operations > 2 hrs, major venous repairCVL, operations > 2 hrs, major venous repair

►Injury-related factorInjury-related factor Spinal factures, coma, pelvic fx, plegiaSpinal factures, coma, pelvic fx, plegia

►AgeAge > 40 (highest risk > 75)> 40 (highest risk > 75)

DiagnosisDiagnosis

► Clinical Clinical featuresfeatures

► ABG ABG ► Chest X-ray Chest X-ray ► EKGEKG► D-DimerD-Dimer

► Lung ScanLung Scan► LE doppler LE doppler ► Spiral CTSpiral CT► PA catheterPA catheter► TTETTE

Gold Standard: Pulmonary Angiogram

Clinical PresentationClinical Presentation

► SymptomsSymptoms Dyspnea 80%Dyspnea 80% Apprehension 60%Apprehension 60% Pleurisy 60%Pleurisy 60% Cough 50%Cough 50% Hemotysis 27%Hemotysis 27% Syncope 22%Syncope 22% Chest painChest pain CHF (right)CHF (right) HypotensionHypotension

► SignsSigns Tachypnea 88%Tachypnea 88% Tachycardia 63%Tachycardia 63% Increased P2 60%Increased P2 60% Rales 51%Rales 51% Pleural rub 17%Pleural rub 17% FeverFever WheezesWheezes JVDJVD CyanosisCyanosis ShockShock

Prospective Investigation of PE Diagnosis: Prospective Investigation of PE Diagnosis: PIOPEDPIOPED

► Prospective trial (817 patients)Prospective trial (817 patients)► Clinical probability - history, PE, CXR, ABG, Clinical probability - history, PE, CXR, ABG,

and EKG prior to V/Q and pulmonary and EKG prior to V/Q and pulmonary angiogramangiogram

► Results:Results:

High likelihood (>80%) High likelihood (>80%) 32 % negative32 % negative Low likelihood (< 20%) Low likelihood (< 20%) 9 % positive 9 % positive IndeterminantIndeterminant 30 % positive30 % positive

Clinical Angiogram

Bottom Line: Subtle Bottom Line: Subtle ManifestationsManifestations

Clinical features are vague, Clinical features are vague, variable, and nonspecific…variable, and nonspecific…

►Unexplained dyspneaUnexplained dyspnea Worsening hypoxia or hypocapnia in Worsening hypoxia or hypocapnia in

spontaneously ventilating patientspontaneously ventilating patient Worsening hypoxia or hypercapnia in a Worsening hypoxia or hypercapnia in a

sedated patient on controlled ventilationsedated patient on controlled ventilation Worsening dyspnea, hypoxemia, and a Worsening dyspnea, hypoxemia, and a

reduction in arterial PCO2 in a patient with reduction in arterial PCO2 in a patient with COPD and known CO2 retentionCOPD and known CO2 retention

ABG’sABG’s

► Typical: hypoxia, hypocarbia, high A-aTypical: hypoxia, hypocarbia, high A-a► Nonspecific and limited value when used aloneNonspecific and limited value when used alone► PIOPEDPIOPED

normal ABG in 38% normal ABG in 38% (without cardiopulmonary (without cardiopulmonary disease)disease)

normal ABG in 14% normal ABG in 14% (with cardiopulmonary disease)(with cardiopulmonary disease)

If present, hypoxia roughly correlates with extent of If present, hypoxia roughly correlates with extent of embolism embolism

as judged by V/Qas judged by V/Q

CXRCXR

► Essential for possible Essential for possible ExclusionExclusion► Poor sensitivity and specificityPoor sensitivity and specificity► PIOPEDPIOPED

85% of PE had abnormal CXR85% of PE had abnormal CXR►atelectasis (most common)atelectasis (most common)►infiltratesinfiltrates►Other findings: Hampton’s hump, Other findings: Hampton’s hump,

Westermark’s sign, enlarged hilum, pleural Westermark’s sign, enlarged hilum, pleural effusion, cardiomegalyeffusion, cardiomegaly

EKGEKG

► Abnormalities are common in PEAbnormalities are common in PE► Diverse and nonspecificDiverse and nonspecific► ChangesChanges

T-wave inversion (most common)T-wave inversion (most common) “ “ Classic “ (uncommon, massive PE)Classic “ (uncommon, massive PE)

►S1, Q3, T3S1, Q3, T3►Pseudo-infarct patternPseudo-infarct pattern►right heart strainright heart strain

EKG - Predicting PEEKG - Predicting PE

► Am J Cardio, 1994Am J Cardio, 1994 49 patients49 patients seven defined features of ischemia/R strainseven defined features of ischemia/R strain if 3/7 positive, 76 % probably PEif 3/7 positive, 76 % probably PE

► Chest, 1997Chest, 1997 80 patients80 patients T-wave inversion in one or more precordialT-wave inversion in one or more precordial 68% of patients with PE68% of patients with PE Reversibility with thrombolysis =good outcomeReversibility with thrombolysis =good outcome

V/Q ScanV/Q Scan

► Most algorithms use V/Q as first stepMost algorithms use V/Q as first step► PIOPEDPIOPED

Most value if very low, low, or high probability Most value if very low, low, or high probability when concordant clinical picturewhen concordant clinical picture

However, However, 4x incidence PE with V/Q very 4x incidence PE with V/Q very low/lowlow/low

►prolonged immobilizationprolonged immobilization►lower limb traumalower limb trauma►recent surgeryrecent surgery►central venous instrumentationcentral venous instrumentation

Probability of PEProbability of PE

Clinical Suspicion V/Q Scan Probability (%)

High High 96

Moderate High 80

Low High 50

Low Low 5

V/Q scanV/Q scan

► PIOPED (understated)PIOPED (understated) majority of patients with suspected PE did majority of patients with suspected PE did notnot

fall into high probability or normal scanfall into high probability or normal scan majority of patients with PE did majority of patients with PE did nonot fall into t fall into

high probabilityhigh probability Most patients without PE did Most patients without PE did nonot have normal t have normal

scanscan Significant percentage of patients with Significant percentage of patients with

intermediate (33%) and low probability (16%) intermediate (33%) and low probability (16%) diddid have PE by angiogram have PE by angiogram

V/Q scans - Newer StudiesV/Q scans - Newer Studies

► Chest, 1996Chest, 1996 223 critically ill patients223 critically ill patients diagnostic utility as accurate as in non-critical patientsdiagnostic utility as accurate as in non-critical patients

► PISA-PED (1996)PISA-PED (1996) presence of wedge-shaped defects regardless of size, presence of wedge-shaped defects regardless of size,

number, or ventilation abnormalitiesnumber, or ventilation abnormalities Grades - normal, near normal, abnormal c/w PE, Grades - normal, near normal, abnormal c/w PE,

abnormal not c/w PEabnormal not c/w PE Sens. 92%, Spec. 87%Sens. 92%, Spec. 87% Selection bias - normal or near-normal no angiogram, Selection bias - normal or near-normal no angiogram,

abnormal 38% no angiogram abnormal 38% no angiogram

V/Q - Can it be done with the V?V/Q - Can it be done with the V?

► CXR + Q = no less positive or negative CXR + Q = no less positive or negative predictive value is high or low probabilitypredictive value is high or low probability

► Others studies supportive if scan is read as Others studies supportive if scan is read as high or low probabilityhigh or low probability

► Indeterminant Q scan, requires V scanIndeterminant Q scan, requires V scan► In cardiopulmonary disease, both V/Q scans In cardiopulmonary disease, both V/Q scans

requiredrequired

V/Q - COPDV/Q - COPD

► PE mimics underlying diseasePE mimics underlying disease► V/Q more limitedV/Q more limited► Chest , 1992Chest , 1992

108 patients with COPD108 patients with COPD 60% fell into intermediate60% fell into intermediate 91% fell into intermediate or low91% fell into intermediate or low However, high probability or normalHowever, high probability or normal

►100% positive and negative predictive 100% positive and negative predictive valuevalue

V/Q “Final Word”V/Q “Final Word”

► A normal scan essentially r/o PEA normal scan essentially r/o PE► A high probability scan with high clinical A high probability scan with high clinical

suspicious confirms PEsuspicious confirms PE► Scan with low or intermediate probability Scan with low or intermediate probability

should be considered nondiagnosticshould be considered nondiagnostic► Perfusion scan alone ok if high probability Perfusion scan alone ok if high probability

or normalor normal

Doppler Doppler ► Valuable roleValuable role► Same therapeutic implications as PESame therapeutic implications as PE► Criteria for diagnosisCriteria for diagnosis

non-compressible (most accurate)non-compressible (most accurate) presence of echogenic materialpresence of echogenic material venous distensionvenous distension loss of phasicity and augmentation of flowloss of phasicity and augmentation of flow

► Sensitive (95%) in symptomatic thrombosis but not Sensitive (95%) in symptomatic thrombosis but not asymptomatic (30-60%)asymptomatic (30-60%)

► Consider serial exams in indeterminant V/QConsider serial exams in indeterminant V/Q

Doppler and Pelvic FxDoppler and Pelvic Fx

► Proximal DVT 25-35% of pelvic fxProximal DVT 25-35% of pelvic fx► Surveillance in asymptomatic patientsSurveillance in asymptomatic patients

ForFor►Van Den Berg et al, Intern Angiology, 1999Van Den Berg et al, Intern Angiology, 1999

Incidence 8.7% trauma patientsIncidence 8.7% trauma patients Aside finding: LMWH + stocking better than Aside finding: LMWH + stocking better than

unfractionated heparin + stockings (DVT 6% vs. unfractionated heparin + stockings (DVT 6% vs. 11.5%, p < 0.05)11.5%, p < 0.05)

AgainstAgainst►Schwarz et al, J of Vasc Surg, 2001Schwarz et al, J of Vasc Surg, 2001

2% incidence of DVT in high-risk trauma patient2% incidence of DVT in high-risk trauma patient Limited use of surveillance doppler in patient on Limited use of surveillance doppler in patient on

LovenoxLovenox

PA catheterPA catheter

► If present at time of PE helpful in diagnosisIf present at time of PE helpful in diagnosis► Therapeutic if hemodynamically unstableTherapeutic if hemodynamically unstable► FindingsFindings

normal wedge pressurenormal wedge pressure marked elevation in right ventricular and marked elevation in right ventricular and

pulmonary artery pressurespulmonary artery pressures

Pulmonary AngiogramPulmonary Angiogram

► Virtually 100% sensitive and specificVirtually 100% sensitive and specific► Expensive and invasiveExpensive and invasive► ComplicationsComplications

5/1111 (0.5%) deaths in PIOPED study5/1111 (0.5%) deaths in PIOPED study 9/1111 (0.8%) nonfatal complications9/1111 (0.8%) nonfatal complications majority of patients were critically ill with sever majority of patients were critically ill with sever

compromised cardiopulmonary function before compromised cardiopulmonary function before procedureprocedure

► “ “ few would argue against the risk of coronary angiogram in few would argue against the risk of coronary angiogram in suspected coronary ischemia, but question often the risk of suspected coronary ischemia, but question often the risk of pulmonary angiogram for the diagnosis of PE”pulmonary angiogram for the diagnosis of PE”

Unproven TestUnproven Test

► EchocardiogramEchocardiogram► Spiral CT scan Spiral CT scan ► D-Dimer (plus ?)D-Dimer (plus ?)► MRI (for DVT)MRI (for DVT)

EchocardiogramEchocardiogram

► TEE more sensitive than TTETEE more sensitive than TTE► Demonstrate intracardiac clot or signs of Demonstrate intracardiac clot or signs of

right ventricular failureright ventricular failure► Emboli observed = 42-50% mortality rateEmboli observed = 42-50% mortality rate► Indirect evidenceIndirect evidence

right ventricular dilationright ventricular dilation dilated pulmonary arterydilated pulmonary artery abnl right ventricular wall motionabnl right ventricular wall motion dilated vena cavadilated vena cava

TEETEE

► Sensitivity/Specificity > 90%Sensitivity/Specificity > 90%► Detects pulmonary truck, right and left main Detects pulmonary truck, right and left main

pulmonary arteries pulmonary arteries ► Incapable of detecting distal pulmonary emboliIncapable of detecting distal pulmonary emboli► Valuable in evaluating for other causes i.e. Valuable in evaluating for other causes i.e.

tamponade, R CHF, dissectiontamponade, R CHF, dissection► Positive test is accurate, negative test non-Positive test is accurate, negative test non-

diagnosticdiagnostic► Primary usefulness unstable patients in ICU Primary usefulness unstable patients in ICU

settingsetting

Spiral CTSpiral CT

role is undefined, but emerging as standard of role is undefined, but emerging as standard of carecare

in some institutionsin some institutions

► Several prospective studiesSeveral prospective studies Sensitive 94%, Specific 96% (Van Rossum, 1996)Sensitive 94%, Specific 96% (Van Rossum, 1996) Greater sensitivity than V/Q (Mayo, 1997)Greater sensitivity than V/Q (Mayo, 1997) Useful in indeterminant V/Q (alternate pathology)Useful in indeterminant V/Q (alternate pathology) Confident diagnosis higher with CT than V/Q Confident diagnosis higher with CT than V/Q

although no difference in detection (Cross, 1998)although no difference in detection (Cross, 1998)

Spiral CT vs V/Q scanSpiral CT vs V/Q scan

► AdvantagesAdvantages probably greater sensitivity proximal emboliprobably greater sensitivity proximal emboli alternate pulmonary pathologyalternate pulmonary pathology after hours availabilityafter hours availability

► DisadvantagesDisadvantages operator dependentoperator dependent lower accuracy for distal embolilower accuracy for distal emboli need for IV contrast ( ? Why not angiogram)need for IV contrast ( ? Why not angiogram)

D-DimerD-Dimer

► Elevated in >90% of patients with PEElevated in >90% of patients with PE► Rises with intravascular coagulationRises with intravascular coagulation► Meta-analysis (29 studies) Meta-analysis (29 studies)

D-dimer alone vs other diagnostic testD-dimer alone vs other diagnostic test

Latex agglutination 48-96 % sensitivityLatex agglutination 48-96 % sensitivity Elisa 88-100% sensitivityElisa 88-100% sensitivity Specificity ranges 10-100 %Specificity ranges 10-100 %

D-Dimer D-Dimer

► Perrier, 1996Perrier, 1996 normal d-dimer and nondiagnostic V/Q normal d-dimer and nondiagnostic V/Q

excludes PE (>90%)excludes PE (>90%)

► Egermayer,1998Egermayer,1998 parametersparameters

►D-dimer positive or negativeD-dimer positive or negative►PaO2 < or > 80 mmHGPaO2 < or > 80 mmHG►RR < or > 20RR < or > 20

D-DimerD-Dimer (Egermeyer, 1998)(Egermeyer, 1998)

► Confirmation with V/Q scan/ AngiogramConfirmation with V/Q scan/ Angiogram► Predictive valuePredictive value

D-dimer negative = 0.99D-dimer negative = 0.99 PaO2> 80 = 0.97PaO2> 80 = 0.97 RR < 20 = 0.95RR < 20 = 0.95 D-dimer plus PaO2 = 1.0D-dimer plus PaO2 = 1.0

► ProblemsProblems Inconsistent confirmation testInconsistent confirmation test ? Patients with pre-diagnosis PaO2 < 80? Patients with pre-diagnosis PaO2 < 80

D-DimerD-Dimer

► Critical deterrentsCritical deterrents problems in development of rapid reproducible problems in development of rapid reproducible

standardized assaystandardized assay clinical conditions in ICU can result in clinical conditions in ICU can result in

accelerated fibrinolysis and elevated d-dimeraccelerated fibrinolysis and elevated d-dimer►recent surgeryrecent surgery►infectioninfection►malignancymalignancy

► Bottom-line: D-dimer useful if negative and Bottom-line: D-dimer useful if negative and V/Q scan low probabilityV/Q scan low probability

ManagementManagement

► AnticoagulationAnticoagulation► Thrombolytic therapyThrombolytic therapy► IVC FilterIVC Filter► EmbolectomyEmbolectomy

AnticoagulationAnticoagulation► Heparin/Coumadin - mainstay therapyHeparin/Coumadin - mainstay therapy► AlternativesAlternatives

Low molecular weight heparinLow molecular weight heparin►no difference in disease recurrence, death, or major no difference in disease recurrence, death, or major

bleedingbleeding►more convenient, but more expensivemore convenient, but more expensive►presently not approvedpresently not approved

Thrombocytopenia and HITThrombocytopenia and HIT►HeparinoidsHeparinoids►HirudinHirudin►AncrodAncrod

Length of TherapyLength of Therapy

► ControversialControversial► Schulman, 1996Schulman, 1996

6 weeks vs 6 months6 weeks vs 6 months former group twice recurrence, no difference former group twice recurrence, no difference

hemorrhagehemorrhage

► British Thoracic Society, 1992British Thoracic Society, 1992 4 weeks vs 3 months4 weeks vs 3 months former significant higher recurrence and failure former significant higher recurrence and failure

of resolution of resolution subgroup post-operative DVT/PE no differencesubgroup post-operative DVT/PE no difference

ThrombolysisThrombolysis

► Significantly accelerated resolution of pulmonary Significantly accelerated resolution of pulmonary emboliemboli

► No significant difference in mortality but trend in No significant difference in mortality but trend in massive PEmassive PE

► ComplicationsComplications significantly higher hemorrhage ratessignificantly higher hemorrhage rates ? Higher stroke rates? Higher stroke rates

► ? role in post-operative patients? role in post-operative patients use of lower dosesuse of lower doses 7-14 days post surgery reported studies7-14 days post surgery reported studies

IVC FilterIVC Filter

► IndicationsIndications ABSOLUTEABSOLUTE

►Contraindication to anticoagulationContraindication to anticoagulation►Failure on anticoagulationFailure on anticoagulation

RELATIVERELATIVE►relative contraindication to anticoagulationrelative contraindication to anticoagulation►free floating iliocaval thrombusfree floating iliocaval thrombus►compromised pulmonary vasculature compromised pulmonary vasculature ►intention to administer thrombolytic therapyintention to administer thrombolytic therapy

IVC FilterIVC Filter► EfficacyEfficacy

No large scale prospective trialNo large scale prospective trial►4% recurrent PE4% recurrent PE►3% caval thrombosis3% caval thrombosis

► Complications (<10%)Complications (<10%) death (0.12%)death (0.12%) filter migrationfilter migration filter erosionfilter erosion IVC obstructionIVC obstruction insertion techniqueinsertion technique

EmbolectomyEmbolectomy

► Trendelenburg pioneered surgery for Trendelenburg pioneered surgery for acute PE in dogs (1920’s)acute PE in dogs (1920’s) No bypassNo bypass SternotomySternotomy Partial occlusion clamps applied to Partial occlusion clamps applied to

pulmonary truck and cavas occludedpulmonary truck and cavas occluded Incised truck and clot removedIncised truck and clot removed

► Predictor of death is preoperative or Predictor of death is preoperative or perioperative deathperioperative death

EmbolectomyEmbolectomy

► IndicationsIndications angiographic evidence of pulm vascular angiographic evidence of pulm vascular

obstruction ( Miller index > 27)obstruction ( Miller index > 27) 60% deficit in perfusion scan60% deficit in perfusion scan refractory hypotensionrefractory hypotension pulmonary hypertension mean > 35 mmHgpulmonary hypertension mean > 35 mmHg

EmbolectomyEmbolectomy► Kieny, 1991Kieny, 1991

reviewed 134 (122 under bypass, 12 modified T-berg)reviewed 134 (122 under bypass, 12 modified T-berg) 30 day survival 84 %30 day survival 84 % DeathsDeaths

►15% bypass15% bypass►41 % modified T-berg41 % modified T-berg

► Meyer, 1991Meyer, 1991 60% survival in 96 patients under bypass60% survival in 96 patients under bypass

► Percutaneous extraction (Greenfield)Percutaneous extraction (Greenfield) 76 % success rate, 30 survival 70%76 % success rate, 30 survival 70%

Newer Prevention Strategies?Newer Prevention Strategies?► Low-weight molecular heparin Low-weight molecular heparin

General SurgeryGeneral Surgery► No significant difference for overall group No significant difference for overall group

Orthopedics Orthopedics ► Total hip and knee arthroplastyTotal hip and knee arthroplasty► Spinal cord injury Spinal cord injury

Oncologic SurgeryOncologic Surgery► More effective than unfractionated heparinMore effective than unfractionated heparin► *Outpatient Prophylaxis (1 month) Bergqvist et al, *Outpatient Prophylaxis (1 month) Bergqvist et al,

NEJM, 346(13):975-80, 2002NEJM, 346(13):975-80, 2002 TraumaTrauma

► Geerts et al, NEJM, 335:701, 1996Geerts et al, NEJM, 335:701, 1996► Knudson et al, J Trauma, 41:446, 1996Knudson et al, J Trauma, 41:446, 1996► Greenfield et al, J Trauma, 42:100, 1997Greenfield et al, J Trauma, 42:100, 1997

Problems with StudiesProblems with Studies

LMWH and Cancer SurgeryLMWH and Cancer Surgery

Mismetti et al, British Journal of Surgery. 88(7):913-30, 2001

LMWH and Trauma LMWH and Trauma

Geerts et al, NEJM, 1996Geerts et al, NEJM, 1996

Trauma and LMWHTrauma and LMWH

Knudson et al, J Trauma, 1996Knudson et al, J Trauma, 1996

Trauma and LMWHTrauma and LMWH

Greenfield et al, J Trauma, 1997Greenfield et al, J Trauma, 1997

Outcomes LMWH in TraumaOutcomes LMWH in Trauma

► Lower incidence of DVT Lower incidence of DVT ► Bleeding complications low overallBleeding complications low overall► Only small studies Only small studies ► Haven’t fully address safety from bleedingHaven’t fully address safety from bleeding► Bottom-lineBottom-line

Better prophylaxis in Better prophylaxis in high-riskhigh-risk patients patients Bleeding risk still unknown vs unfractionated Bleeding risk still unknown vs unfractionated

heparinheparin Mutlicenter trial needed to assess bleeding riskMutlicenter trial needed to assess bleeding risk

SummarySummary► Prevention of DVT/PEPrevention of DVT/PE

Identify patients at risk (most if not all surgery patients)Identify patients at risk (most if not all surgery patients) Methods vary Methods vary

► Consider high risk patients for LMWH Consider high risk patients for LMWH ► IVC filter in patients you can not anticoagulantIVC filter in patients you can not anticoagulant

? Surveillance doppler in high-risk asymptomatic patients ? Surveillance doppler in high-risk asymptomatic patients ► Probably of benefit in pelvic fractures Probably of benefit in pelvic fractures

► PE DiagnosisPE Diagnosis High level of suspicion even if with only symptom is High level of suspicion even if with only symptom is

dyspneadyspnea Spiral CT scan with IV contrast excellent to rule-out Spiral CT scan with IV contrast excellent to rule-out

proximal PE and other lung parenchyma disease, but proximal PE and other lung parenchyma disease, but limited limited

Consider pulmonary angiogram if suspicion high and other Consider pulmonary angiogram if suspicion high and other test equivocal test equivocal

Questions…?Questions…?