Respiratory 3 - Hot topics in respiratory medicine (2) Flashcards
What is the strongest risk factor for development of VTE?
Myocardial infarction in the last 3 months
What are features of epidemiology of PE?
0.5-2/1000 per year
higher incidence in african americans, lower in Asians, Pacific Islanders
M:F 56 vs 48/100k
Females have lower recurrence rates
Increased risk with increasing age (risk doubles every decade after 40)
What is the natural Hx of VTE?
30 day mortality for VTE 11%
90 day 9-17%
12 month 30%
Treatment reduces mortality to
What are STRONG risk factors for VTE? (OR>10)
Fracture of LL Hospitalisation for CHF or AF/Flut Hip or knee replacement Major trauma Myocardial infarction within 3 months Previous VTE Spinal cord surgery
What are moderate RFs for VTE? (OR 2-9)
Arthroscopic knee surgery AI diseases Blood transfusion CVLs Chemotherapy CHF/respiratory failure EPO HRT IVF Infection (esp pneumonia, UTI, HIV) IBD Cancer (higher if metastatic) OCP Paralytic stroke Post partum Superficial vein thrombosis Thrombophilia
What are weak risk factors for VTE (OR
Bed rest >3 days DM HTN Immobility due to sitting Increasing age Laparoscopic surgery Obesity Pregnancy (up to 60x risk in T3, and 6 weeks post partum) Varicose veins
What are expected VTE recurrence rates whilst on A/C?
2% at 2 weeks
6.4% at 3 months
8% at 6 months
Active cancer and failure to achieve therapeutic A/C increase the risk
What are rates of late recurrence?
Generally >6 months, and off A/C
13% at 1 year
23% at 5 years
30% at 10 years
Recurrent risk higher in unprovoked VTE, multiple VTE, OCP, PE, proximal DVT and elevated d-dimer
What clinical features are assigned the highest score in the Well’s rule?
Clinical signs of DVT = 3 Alternative diagnosis less likely than PE =3 Previous DVT/PE = 1.5 Heart rate >100 = 1.5 Surgery or immobilisation within 4 weeks = 1.5 Haemoptysis = 1 Active cancer = 1 >4 points = PE likely
What clinical features are associated with the highest score on the geneva score?
HR >=95/min = 5 points Pain on lower limb venous palp/unilateral swelling = 4 Prev DVT/PE = 3 Unilateral lower limb pain = 3 HR 75-95 = 3 Surgery/# within 1/12 = 2 Haemoptysis = 2 Active cancer = 2 Age >65yo = 1
> 5 points = PE is likely
What tests are best at diagnosis VTE?
CTPA - but good at overdiagnosis
VQ - high probability scan only
Compression USS
What are tests for excluding VTE?
d-dimer - in low and intermediate risk groups
CTPA - if negative and high pre-test probability -requires further investigation
V/Q - low probability scan excludes VTE, but 50% are reported as non-diagnostic
What is the most Specific d-dimer assay?
ELISA quantitative method has a negative LR of 0.01
Latex quant 0.2
Latex semiquant 0.20
Haemagllutination 0.31
What is the role of CT venography in CTPA?
Addition of CTV to CTPA improves Sn but has no change in NPV or Sp - and results in higher radiation dosages
What is the relationship between NPV, PPV and clinical probability in CTPA?
Has low PPV in low clinical probability groups, and a low NPV in high clinical probability groups.
When there is clinical discrepancy between clinical probability and CT results - should consider further testing
What is the relationship between CTPA and overdiagnosis?
PE incidence increased following CTPA introduction, however there has been a progressive fall in PE mortality, with increasing rates of complications from anticoagulation.
CTPA will diagnose clinically unimportant emboli and lead to overtreatment.
What is the significance of subsegmental PE?
Isolated subsegmental PE of questionable clinical significance.
9.4% of patients on MDCT
Inter-observer agreement low
? role of compression USS in this group
What are features of VQ scanning?
3 outcomes - normal (excludes PE), High probability and non-Dx (50% of scans)
Lower radiation dose generally.
Usually for pts with contrast allergy, renal failure, myeloma.
Perfusion scan alone is adequate in patients with normal CXR
What is the role of Comp USS in DVT/PE?
most PEs from DVT
70% pts with PE have DVT on venography
Comp USS - Sn >90%, Sp 95%, DVT ident in 30-50% of patients with PE
What is the role of echo in PE?
only 30-40% of patients with PE have echo features consistent with PE.
NPV only 40-50%
Useful in stratification of patients who may be high risk
What features make PE high risk?
Shock or hypotension
- SBP =40 for >15 minutes
not caused by arrhythmia, sepsis or hypovolaemia
What are adverse prognostic factors in PE on imaging?
RV dysfunction 2ndary to PE = 2x mortality
Rv thrombus - 14 day mortality 21 vs 11%, 3 month 29 vs 16%
Co-existant DVT increases all cause mortality by 2 and increased specific PE mortality by 4.25
What is the relationship between BNP and mortality in PE?
600 = increased risk of morbidity
What are other prognostic serum factors in PE?
troponin elevation - OR5.24 for short term mortality and 9.44 PE-specific mortality
Hyponatraemia - mild 1.53 OR, 2 increases mortality from 1.6 to 17.3%
What is the role of PESI?
to identify low risk patients (low risk 1% mortality rate and 10% in high risk (at 30 days)
Simplified - >=1 point = high risk Age >80 +1 Cancer +1 CHF +1 Chronic pulmonary disease +1 HR >110 +1 SBP
What patients are eligible for outpatient treatment of PE?
PESI I or II - no difference in VTE rates at 3 months and no significant difference in bleeding rates
Patients with BNP
What period of treatment is recommended with non-oral A/C in acute PE?
5-10 days, with overlap of warfarin with heparin
What are advantages of LMWH vs UFH?
lower mortality
lower recurrence rates
reduced thromboembolic events
less major bleeding
What is the role of testing for CYP2C9 and vit K epoxide reductase genes in warfarin?
genes account for >1/3 of variability of in warfarin dosing
current evidence is equivocal as to clinical utility of testing
What is the duration of therapy for provoked DVT?
3 months
What is the duration of therapy in active cancer?
3-6 months, and consider indefinite treatment
LMWH is more effective than warfarin in these patients
20% risk of recurrence in 1st 12 months
What is the minimum treatment duration in patients with unprovoked DVT?
at least 3 months of treatment - if high risk of bleeding complications, limit to 3 months total duration.
If low or moderate risk - indefinite therapy
Reduce risk of recurrent VTE by 90% (warfarin), with 1% or higher annual risk of bleeding
What patients may benefit from indefinite treatment with vit K antag?
Recurrent VTE Antiphospholipid syndrome hereditary thrombophilia (homozygotes) residual thrombus in prox veins persistent RV dysfunction on echo
What is the role of aspirin post unprovoked DVT/PE
30-35% risk reduction in recurrence post std anticoag, but anticoag provides 50% reduction.
lower bleeding rates with aspirin
What is the role of NOACs in the long-term treatment of DVT/PE?
dabigatran non-inferior wrt efficacy and lower rates of major bleeding.
rivaroxaban - no difference in PE recurrence and minor decrease in major bleeding (t1/2 is short- risk of recurrence high w missed dose)
apixaban - non-inferior to warfarin, less major bleeding
edoxaban - less bleeding, non inferior
overall meta analysis, just reaches unity for bleeding risk favoured in noacs
What are absolute contraindications for thrombolysis in PE?
Haemorrhagic stroke or stroke of unknown origin at any time.
Ischaemic stroke in past 6 months.
CNS damage or neoplasms
Recent major trauma, surgery head injury in last 3/52
GI bleed in last month
Known bleeding risk
What are relative contraindications for thrombolysis in PE?
TIA in last 6 months oral AC therapy Pregnancy or one week post partum Non-compressible puncture site Traumatic resuscitation Refractiory hypertension (>180) Advanced liver disease Infective endocarditis Active peptic ulcer
In what patients is thrombolysis beneficial?
patients who are hypotensive/haemodynamically unstable have been shown to be afforded benefit in thrombolysis in PE
In submassive PE, what are the outcomes of thrombolysis?
Shown to reduce rates of therapy escalation but not mortality. Soft endpoint.
Intermediate risk PE - shown to increase bleeding, but not death.
Low dose thrombolysis has shown faster resolution of PE but similar rates of bleeding, recurrence and death.
What about low dose thrombolysis in massive PE?
Lower mortality and bleeding in low dose group, with no fatal recurrent VTE in either group (no comparison placebo arm)
What are features of IVC filters in PE?
reduced short term PE mortality
Increased risk of recurrent VTE ~20%
Post thrombotic syndrome in 40%
Occlusion of IVC - 22% at 5 years, 33% at 9 years regardless of A/C
What is the prognosis of untreated subsegmental PE?
no patients died of PE at 3 months if untreated, but 16% had bleeding complications if treated.
What is the definition of pulmonary hypertension?
PAPm >=25mmHg
Precapillary PH: PAPm >=25mmHg, PAWP =25mmHg, PAWP >15mmHg
What are classifications of pulmonary HTN?
- Pulmonary arterial hypertension
- PH due to LHD
- PH due to lung Dz or hypoxia
- Chronic thromboembolis PH
- PH with unclear multifactorial mechanisms
What are causes of PAH?
Idiopathic PAH
Heritable PAH - BMPR 70%, ALK1, ENG, SMAD, CAV1, KCNK3
Drugs (cocaine, rapeseed, anorectic drugs)
Associated with:
CTD, HIV, portal HTN, Congenital heart disease, Schistosomiasis
What are clinical features of pAH
non specific: dyspnoea fatigue syncope peripheral oedema angina
How is PAH diagnosed?
Requires clinical suspicion: consider features of underlying disease consider screening high risk groups: - CTD - HIV - hereditary PAH - ECG - Right axis deviation - Spirometry and TCLO - Anti-centromere Ab - pro BNP - Serum urate - Echocardiogram (>=3.0 m/sec tricuspid regurgitation)
What is the relationship between screening and prognosis in SSc?
Improved survival when patients with SSc are screened for PAH
What is the best 1st screening test for PAH?
Echocardiogram - looking for tricuspid regurgitation, RVSP.
If a high or intermediate risk echo, what is the next step in PAH diagnosis?
Consider left heart disease and lung diseases - if confirmed, refer to PH centre for review if signs and Sx of severe PH/RV dysfunction.
If patient without symptoms, treat the underlying disease.