Pulm E2- Pulm Circulation Disorders

what is a pulmonary embolism?

what is a pulmonary embolism?

obstruction of the pulmonary artery or one of its branches by material that originated elsewhere in the body;

most commonly arises from thrombus in deep venous system of lower extremities

PE is more common in ____

males

what is Virchow’s triad?

hypercoagulability, venous stasis, endothelial injury

what is the pathophysiology of a PE?

• thrombus travels to pulm vasculature → obstruction → inc in pulm vasc resistance → pulm HTN → RV failure

• inc dead space → impaired gas exchange → inc CO2 → hyperventilation / tachypnea

• inflame response secondary to chemical mediators released by thrombus → bronchoconstriction of small airways, vasoconstriction, surfactant dysfunction and atelectasis, V/Q mismatch = hypoxemia

• pulm infarction if smaller peripheral vessels occluded

what are the classifications of a PE?

Hemodynamically unstable: hypotension (SBP < 90 or DBP drop 40); more likely to die from obstructive shock (ex RVHF)

hemodynamically stable: ranges from mild sx to asx; mild hypotension that resolves w/ fluids

what are risk factors for PE?

• genetics (thrombophilia, factor V leiden, prothrombin gene mutation, protein C or S def, hyperhomocysteinemia)

• prolonged immobilization

• recent ortho surgery

• malignancy

• indwelling venous catheter

• obesity

• pregnancy

• smoking

• hormone replacement therapy

what are sx of a PE?

• dyspnea- typically acute and severe

• pleuritic chest pain

• cough ± hemoptysis

• presyncope or syncope

• less common: arrhythmias, sudden cardiac arrest, syncope, dizziness, hemodynamic collapse

what are you looking for on a physical exam of a PE?

• tachypnea, tachycardia

• hypoxia

• signs of DVT- unilateral calf swelling/erythema and homan’s sign

• signs of pulm HTN

• signs of RV failure

what labs to order for PE?

• ABG: hypoxemia, resp alkalosis w/ hypocapnia

• CBC: WBC normal or elevated

• CMP: renal function and electrolytes

• Cardiac Enzymes BNP & Trop: elevated, assoc w/ inc RV afterload, prognostic not diagnostic

• D-Dimer: not useful for confirmation; high neg predictive value w/ low pos predictive value

what imaging studies can be ordered for PE?

• EKG: tachycardia MC, nonspecific ST and T wave inversion, S1Q3T3 rare

• CXR: typically normal; hampton’s hump, westermarks sign

• venus Doppler u/s to evaluate LE DVT

• lung scintigraphy/ VQ scan: when CTA is contraindicated and in pregnancy

• CT pulm angiography: gold standard; contraindicated in iodine contrast allergy and renal insufficiency

• catheter based pulmonary angiography: invasive and expensive; rarely used

what imaging study is the gold standard for PE?

CT pulmonary angiography

what is the diagnostic test of choice for a PE in pregnancy?

lung scintigraphy / V/Q scan

what is hamptons hump?

rare; wedge shaped, pleura based triangular opacity w/ an apex pointing toward the hilus

pathognomic for PE

what is westermarks sign?

rare; sharp cut off of pulmonary vessels w/ distal hypo perfusion in a segmental distribution w/in the lung

pathognomic for PE

what is used for risk stratification and clinical decision criteria to esteem the probability for acute PE?

wells / modified wells critera

what is well’s criteria?

• S&S of DVT → 3

• PE is likely #1 dx → 3

• HR > 100 → 1.5

• immobilization ≥3 days or surgery is past 4 wks → 1.5

• PMHx PE or DVT → 1.5

• hemoptysis → 1

• malignancy w/ tx w/in 6 mos or palliative → 1

what criteria is used to determine if a low risk pt warrants further evaluation for PE?

pulmonary embolism rule out criteria (PERC)

what is PERC?

• age < 50

• HR < 100

• SaO2 ≥ 95%

• no hemoptysis

• no estrogen use

• no surgery/trauma requiring hospitalization w/in 4 wks

• no prior VTE

• no unilateral leg swelling

low risk pts only, if any criteria is positive → can’t r/p PE

if score 0 → <2% chance of PE

what is the clinical prediction tool to determine pre test probability of a PE based on risk factors and clinical findings and has a greater degree of standardization?

geneva score

what is Geneva score?

• age > 65 → 1

• previous DVT or PE → 3

• surgery or LE fracture in previous wk → 2

• active cancer → 2

• unilateral LE pain → 3

• hemoptysis → 2

• HR 75-94 → 3

• HR ≥ 95 → 5

• pain on leg palpation or unilateral edema → 4

0-3 pts: low prob; 4-10 pts: intermediate prob; ≥ 11 pts: high prob

How would this PE be classified?

• SBP < 90 or drop of ≥40 in > 15 min

• possible RV dysfunction w/ progression to obstructive shock

• death often occurring in first 2 hrs

hemodynamically unstable

How would this PE be classified?

• stable BP

• mildly sx or asx

hemodynamically stable

what is tx for a hemodynamically stable PE?

• supplemental O2

• peripheral IV access (± IVFs)

• empiric anticoagulation

  • LMWH: Enoxaparin (Lovenox)

  • Fondaparinux (Arixtra)

  • unfractionated heparin → preferred in severe renal failure

• if anticoagulation contraindicated → IVC filter

what is an inferior vena cava filter?

• blocks path of LE venous emboli from entering pulm circulation

• indications:

  • pts w/ VTE who have absolute contraindication to anticoagulants

  • recurrent VTE and PE

• retrievable filters preferred

what is tx for hemodynamically unstable PE?

• low bleed risk w/ no contraindications → thrombolytics (tPA) [preferred w/in 48 hrs sx onset]

• if thrombolytics contraindicated

  • surgical embolecteomy

  • percutaneous catheter directed therapy

  • ECMO

• surgical embolectomy → required cardiopulmonary bypass

• catheter directed therapy

what are thrombolytics (tPA)?

• able to rapidly dissolve embolic burden and improve cardiorespiratory hemodynamics

• MOA: activates plasminogen to plasmic which accelerates lysis of thromboemboli

• potential comp → hemorrhage

• ex: ateplase (activase)

what are absolute contraindications to tPA?

• any prior intracranial hemorrhage

• known intracranial malformation or neoplasm

• ischemic stroke < 3 mo

• suspected dissection

• recent surgery

• recent head trauma

• bleeding diathesis

what are relative contraindications to tPA?

• age > 75

• current anticoagulants

• pregnancy

• CPR > 10 min

• recent internal bleed 2-4 wks

• uncontrolled HTN (180/110)

• remote ischemic stroke

• major surgery w/in 3 wks

what is a surgical embolectomy?

• invasive procedure to remove clot; requires cardiopulmonary bypass

• indications:

  • hemodynamically unstable pt

  • when thrombolysis contraindicated or failed

• potential comps → perforation of pulm artery, cardiac arrest, bleeding

what is catheter directed therapy?

• infuse thrombolytics directly into pulm artery

• clot removal via u/s assisted thrombolysis, suction embolectomy, or thrombus fragmentation

• success rate 87%

• possible comp → perforating pulm arteries leading to massive hemorrhage or cardiac tamponade

what is venoarterial extracorporeal membrane oxygenation (V-A ECMO)?

• advanced form of life support used in pts w/ severe respiratory or cardiac failure when conventional tx has failed

• can be used for pts w/ massive PE in which thrombolytics are contraindicated

what should all PE patients receive to prevent recurrence?

≥3 mos of anticoagulant tx (up to a year if PE unprovoked or persistent risk factors)

• preferred: oral factor Xa inhibitors

  • Apixaban (Eliquis)

  • Rivaroxaban (Xarelto)

• severe renal insuf: warfarin; monitor PT/INR (goal 2-3)

• alt:

  • LMWH (Lovenox)

  • Fondaparinux (Arixtra)

what is pulmonary HTN?

• elevated pulmonary arterial pressures

  • inc in mPAP ≥ 20 at rest

  • pulm cap wedge pressure > 15

• MC in women

what are the most frequent causes of pulmonary HTN (PH)?

left heart disease and lung disease

what is group 1 pulmonary arterial HTN?

• idiopathic PAH (MC)

  • inc vascular resistance and blood vessel narrowing w/in pulm vasculature; unknown cause

• heritable PAH aka familial or genetic PAH

  • uncommon; possible molecular/genetic causes

• assoc w/ chronic conditions

  • CT dz, congenital heart dz, chronic liver dz, HIV, drugs, toxins

what is group 2 PH?

d/t left heart disease; assoc w/ impaired exercise activity and reduced survival

what is group 3 PH?

d/t chronic lung dz or hypoxemia; ex- COPD, interstitial lung dz

what is group 4 PH?

d/t pulm artery obstructions; ex- PE

what is group 5 PH?

d/t unclear multifactorial mechanisms; ex- sarcoidosis, sickle cell anemia, thyroid disorders, etc

what is the pathophysiology of group 1 and 2 PH?

• inc vascular resistance and blood vessel narrowing occur w/in pulm vasculature

• PAH: molecular/genetic changes → hypertrophy of smooth muscle, endothelial cells, adventitia → restricted flow through pulm arts → inc vascular resistance → RV inc filling and SV → inc pulm art pressure

• LHD: inc in LA/LV filling pressure → dec compliance of pulm arts promoting stiff pulm vasculature

what are ssx of PH?

• progressively worsening dyspnea - typically starts w/ exertion

• dull retrosternal CP

• dizzy/syncope

• fatigue

• nonproductive cough

• peripheral edema

• partner syndrome- compression of recurrent laryngeal n. by enlarged pulm artery

what are PE findings of PH?

• dyspnea

• sx of RHF

  • JVD

  • loud P2

  • R murmurs (tricuspid regurg)

  • hepatomegaly

  • peripheral edema

  • ascites

what is diagnostic workup for PH?

• blood tests: not useful

  • normal-elevated BNP → marker for RV dysfunciton

  • normal-elevated LFTs → high hepatic venous pressure

• PFTS: assess for obstructive or restrictive lung dz

• CXR: eval for cardiomegaly, inc RV size or pulm vascular congestion

• ECG: eval sx of LHD, LVH, RAD, RVH, RBBB, etc (normal does not exclude dx)

• TTE: noninvasive screening test of choice

  • pulm art systolic pressure > 40

  • mPAP of 25

• right heart catheterization: measurement of mPAP & PCWP

  • mPAP > 25 w/ PCWP > 15 = left heard dz

• vent/perfusion scintigraphy

• high res CT: provide clues of classification and prognostic info

what is the gold standard to confirm dx of PH?

right heart catheterization

what is the goal of tx for PH?

prevent progression and tx underlying dz if present

what are all possible tx for PH?

based on sx and severity

• pulm rehab and active physiotherapy

• supplemental O2 for hypoxia

• diuretics for volume overload

• tx for anemia

• vasodilators

  • endothelin receptor antags (ERA) → ambrisentan, bosentan, macitentan

  • PDE5 inhibitor (PDE5I) → sildenafil, tadalafil

  • prostacyclin analogue → epoprostenol

  • guanylate cyclase stimulant (sGC) → riociguat

• digoxin: slow vent rate for atrial tachyarrhythmia

• CCB: lower PAP and vasc resistance for pts w/ positive vasoreactivity during right heart cath (Nifedipine, diltiazem, amlodipine)

what are pros and cons of epoprostenol (flolan)

• Pros:

  • inc surfactant production

  • improve V/Q mismatch

  • reduce pulm vasc resistance

  • improve RV performance

• Cons:

  • inhibit plt function

  • short half life- avoid circuit interruptions

what is tx for low or intermediate risk PH (class II-III)?

combo tx ERA and PDE5I

alt: PDE5I and sGC stimulant

what is tx for high risk PH (class IV)?

Trimble combo ERA, PDE5I, and IV prostacyclin analog

what is another name for cor pulmonale?

pulmonary heart

what is cor pulmonale?

alteration in structure and function of RV caused by dz of lung or pulmonary vasculature (PH common link)

what are possible causes of cor pulmonale?

COPD, massive PE (MC acute), PH, interstitial lung dz

what is the MC cause of acute cor pulmonale?

massive PE

what is the pathophysiology of cor pulmonale?

inc PAP → inc RV afterload → RV dilatation and inc RV EDP

RV pressure and volume overload → septal displacement towards LV → dec LV filling volume → dec CO

what are sx of cor pulmonale?

• dyspnea on exertion- MC

• fatigue / lethargy

• exertional syncope

• exertional CP

• chronic productive cough

what are PE findings of cor pulmonale?

• tachypnea

• JVD

• cyanosis

• hepatomegaly

• ascites

• palpable left parasternal lift

• loud S2

• systolic murmur of tricuspid regurg

what is the diagnostic workup for cor pulmonale?

• CXR: enlarged pulm artery, cardiomegaly

• EKG: RAD, RVH, tachyarrhythmias

• TTE: RVH, sx of PH

• ABG

• PFT and 6 minute walk test: assess severity

• R heart catheterization: evidence of RV dysfunction w/o LV dysfunction, assess PH severity

• Labs:

  • H/H: eval for polycythemia

  • ANA: screen for collagen vascular dz

  • coagulation studies

  • BNP

what is the gold standard for diagnosis or cor pulmonale?

right heart catheterization

what is the goal of treatment of cor pulmonale?

improve oxygenation and RV function; inc RV contractility and dec pulm vasoconstriction

what is tx for cor pulmonale?

• O2 therapy: relieve hypoxemia pulm vasoconstriction

• diuretics: dec RV filling volume (caution- can cause hypokalemic metabolic alkalosis)

• CCB: lowers pulm pressures

• pulm vasodilators: support RV function via dec PVR

  • prostacyclin analogues- epoprostenol

  • ERA- bosentan

  • PDE5I- sildenafil