Diagnosis and management of pulmonary thromboembolismDR.VIVEKANANTHAN D.A.,FRCA.,EDIC.,FFICM.,

OVERVIEW

Diagnosis – tests available and diagnostic strategies used

Prognostic assessment

Management- therapeutic strategies and methods available

Special circumstances

Pulmonary thromboembolism

Venous Thromboembolism (VTE) spectrum- DVT & PE

Major morbidity and mortality

Not uncommon

Diagnosis could be Elusive

Risk factors

pathophysiology

Diagnosis- Symptoms galore!

Pollack et.al 2011

pitfall amongst symptoms and signs

30% patients with Confirmed PE do not have predisposing factors

40% patients with confirmed PE do not have hypoxaemia

20% patients with confirmed PE have normal alveolar arterial oxygen gradient

40% patients with confirmed PE have sinus tachycardia on ECG rather than classical ECG changes

59% of fatal PE were undiagnosed during life time

Acute PE- Initial diagnostic strategy

With shock and without shock-

High risk PE

Moderate and low risk PE

Diagnosis -Assessing clinical probability

Wells rule

Geneva rule

Three group category -Low, intermediate, high risk grouping

Two group category- PE likely, PE unlikely grouping

WELLS RULE

GENEVA RULE

Diagnosis- D-dimer

Positive predictive value is low

Negative predictive value is high

ELISA derived assay Vs latex derived assay reliability

Usefulness- can exclude PE in up to 30% of patients suspected with low or intermediate risk PE- (class I recommendation)

Age adjusted D-dimer cut off value improved specificity by 10%, if not specificity decreases with age

Diagnosis- CT pulmonary angiogram

83% sensitivity and 96% specificity –PIOPED II trial

Negative predictive value for CTPA is >89-96% in intermediate and low risk group

Segmental clot presence confirms PE -(class I recommendation)

CT venography combined with CTPA increases sensitivity from 83 to 90%, however specificity remains the same

Incidental CT diagnosis of PE is 1%

Sub segmental PE incidence is 4.5% with lower clinical significance

Diagnosis- ventilation perfusion scintigraphy

V/Q scan- technicium99

Well validated test

Safe, less allergic, <50% radiation exposure

Special groups of patients will benefit from it

Results are grouped into three- normal, high probability and non diagnostic scan

Diagnosis- other imaging techniques

SPECT imaging-

Pulmonary angiogram-

DSA-

MRI-

Diagnosis- Echocardiography

RV free wall contractility depressed as against the apex- “Mc Connell sign”

Disturbed RV ejection fraction- “60-60 sign”

RV dilatation – found in 25% of all cases of PE

Negative predictive value is only 40-50% due to other confounders

Not an investigation for low risk, non shocked patients

Diagnosis- compression venous ultrasonography

90% sensitivity and 95% specificity for symptomatic DVT

>70 % of PE patients have DVT

Proximal DVT in PE suspected patients is good enough to start anticoagulation- (class I recommendation)

Incomplete compressibility is a validated criterion for DVT diagnosis

Flow measurements are unreliable

Diagnostic strategy

Patients suspected to have PE, presenting

With shock

Without shock

Suspected PE with shock

Suspected PE without shock

PE exclusion -validated parameters

Treatment of PE- Overview

Haemodynamic, ventilatory support

Anti coagulation

Thrombolysis

Surgical embolectomy, percutaneous techniques, use of IVC filter

Treatment- resuscitation and supportive care

RV failure- main cause for mortality

adrenaline helps in RV failure

Modest fluid challenge helps improve cardiac index- caution needed

Effects of PEEP during ventilation needs careful titration

Levosimendan and nitric oxide might be useful

Treatment- anticoagulation

To prevent early death and recurrent VTE

Initial parenteral anticoagulation for 7-10 days necessary- heparin, LMWH, fondaparinux

vit.K antagonist after the initial phase for up to 3 months duration is essential

Duration of anticoagulation- unprovoked PE ( 3 months) unprovoked relapse of PE ( indefinite)- (class I recommendation)

Newer anticoagulants can be started earlier- rivaroxaban, apixaban

Treatment- choice of anticoagulant

UFH- shorter duration of action, suitable for pt. with renal impairment, obesity, APPT monitoring needed

LMWH- twice daily or single dose administration, caution with renal impairment, HIT possibility, anti Xa level monitoring possible

Fondaparinux- once daily s/c inj. , results comparable to that of UFH, no reported HIT like effects, accumulates in renal failure

Treatment- oral anticoagulants

Warfarin –Vit K Antagonist(VKA) started as soon as possible, INR target of 2.0-3.0 is aimed

Pharmacogenetics' guided therapy is not found to be superior

Newer oral anticoagulants (NOAC)- dabigatran, rivaroxaban.,

NOAC- not inferior to UFH/ VKA regimen, possibly the bleeding risk is lesser –(class I recommendations for rivaroxaban apixaban and edoxaban)

Treatment- thrombolytic therapy

Restores pulmonary perfusion earlier than anticoagulation therapy

Two hours’ accelerated therapy preferred over 12-24 hour prolonged infusion therapy

>90% patients have clinical recovery within 36 hours of therapy, greatest benefit seen if therapy initiated within 48 hours of onset of symptoms

Normotensive patients with raised biochemical parameters and echocardiographic features of RV dysfunction, if thrombolysed, 7 day mortality and further complications were prevented (PEITHO trial)

Major bleeding risk- intra cranial and non intracranial bleeds- 2%

Treatment- surgical embolectomy

Surgical technique used since 1924

Indicated for failed thrombolytic therapy or where it is contraindicated amongst intermediate or high risk patients

Treatment- percutaneous catheter directed treatment

Thrombus fragmentation, rotational thrombectomy, suction thrombectomy, rheolytic thrombectomy techniques are available

Systemic Thrombolysis contraindicated patients are suitable for these techniques

RCT: Catheter directed clot thrombolysis technique has been found superior in reversing RV function within 48 hours as compared to systemic thrombolysis WITHOUT bleeding complications in intermediate risk group of patients

Treatment – IVC filter

Infra renal placement is usually done

IVC filters should be considered in patients with acute PE with absolute contraindications to anticoagulation. ( class II a recommendation)

IVC filters should be considered in case of recurrence of PE, despite therapeutic levels of anticoagulation. ( class II a recommendation)

Routine use of IVC filters in patients with PE is not recommended ( class I recommendation)

Special circumstances- pregnancy

D-Dimer is useful to avoid unnecessary irradiation

Venous compression ultrasonography is considered to avoid irradiation risk

Perfusion scintigraphy may be considered to rule out suspected PE when the chest x ray is normal

CT angiography considered only when chest x ray is abnormal

LMWH adjusted to weight is treatment of choice in pts without shock

Special circumstances- cancer and PE

Incidental PE on cancer screening is treated along the same guidelines for non cancer patients suspected to have PE

Negative D-dimer has similar negative diagnostic value

LMWH adjusted to body weight is used for 3-6 months

Extended anticoagulation with LMWH is considered until cancer is cured- (class II a recommendation)

Chronic thromboembolic pulmonary hypertension

Incidence of 1.5 % in patients diagnosed with earlier PE

Diagnostic criteria: findings after 3 months of effective anticoagulation:

1. mean pulmonary arterial pressure ≥25 mm Hg, with pulmonary arterial wedge pressure≤15 mm Hg

2. at least one (segmental) perfusion defect detected by perfusion lung scan or pulmonary artery obstruction seen by MDCT angiography or conventional pulmonary cine angiography

V/Q scan is investigation of choice

Pulmonary endarterectomy offered if operable, if not extended anticoagulation advised - (Class I recommendation)

Prognosis in PE

Simplified predicted severity in PE (sPSE score)- validated clinical score

Age >80, Cancer

Chronic cardiac, pulmonary disease

Heart rate >110, blood pressure <100, saturation <90%

0 points =1% mortality, >1 point= 10% risk of 30 day mortality- used for low and intermediate severity- ( class II a recommendation)

Patients to be assessed for presence of shock- carries higher mortality – (class I recommendation)

Lab tests and biomarkers- BNP, Pro BNP, troponin T, I ( class II a)

acknowledgment

http://www.escardio.org/guidelinessurveys/esc-guidelines/about/Pages/rules-writing.aspx

European society of cardiology guideline 2014

European heart Journal August 2014

Summary- Diagnosis and treatment of PE

Strong clinical suspicion is necessary to investigate and use the diagnostic strategies

Judicious use of investigations will avoid unnecessary burden in patient care delivery

Choice of therapy is vital in dictating better patient outcome

Thank you