Vascular Disease

    Abdominal Aortic Aneurysm

    • Physical Exam:
      • JAMA RCE: Palpable pulsations > 2.5cm require follow-up investigations.
    • Indication for repair of AAA:

      • Size: > 5.5 cm
        • Consider for > 4.5cm if getting other cardiac surgery
      • Rate:  > 0.5cm/yr

       

      (Source: NEJM Knowledge)

     

    • Management
      • Non-pharmacologic
        • Smoking Cessation (smokers have double speed of progression)
        • BP control lifestyle modifications
      • Pharmacologic
        • ACEi, etc.. for BP control
      • Surgical
        • Two methods:
          • Endovascular Aneurysm Repair (EVAR)
          • Open Repair
        • Advantages/Disadvantages:
          • RCT:  EVAR = lower perioperative morbidity/mortality compared to open AAA repair
          • EVAR does not completely eliminate future AAA rupture risk.
          • Open repair = higher peri-OP morbidity/mortality but provides a more definitive repair. 
      • Surveillance:
        • Optimal Surveillance not defined, typically once/year with preferably CT or MRI is recommended (Ultrasound less preferred)
      • Source:
        • NEJM Knowledge question

    Peripheral Vascular Disease (Chronic)

    • Inadequate cell nutrition due to poor blood supply
    • Atherosclerosis in vessels.  Subintimal, heterogeneous (can have Ca)
    • Risk Factors:
      • Smoking ++++
      • Diabetes +++
      • Age ++
      • Hypertension +
      • Hypercholesterolemia +
    • Chronic arterial changes:
      • Hair loss, cold, rubor (not cellulitis), ulceration (gangrene)

    Chronic Ischemia

    • Classified as:
      • Claudication (pain with movement)
        • Pain (any muscle group, can even be bowel - mesenteric angina)
        • Predictable (on movement)
        • Disappears (completely gone at rest)
      • Critical Ischemia
        • Pain at rest
        • Pain at night
        • Non-healing ulcer
    • Claudication: risk of limb loss is low (5% in 5-10yrs)
    • Critical Ischemia: risk of limb loss high.  High mortality from CVD (50% in 5 yrs)

    Investigations

    Ankle Brachial Index

    • ABI (for that leg) = highest tibial pressure (for that leg) / highest brachial pressure.
      • Use U/S probe to check pulse.
    • Interpretation of ABI

      • ABI Reading Interpretation
        > 1.4

        Noncompressive vessels (non-diagnostic - use toe)

        ABI < 0.70 in big toe = abnormal (PAD)

        1.01 - 1.40 Normal
        0.91 - 1.00 Borderline (usually represents arterial disease)
         0.5 - 0.9 Abnormal (claudication)
        <0.5 Very Severe (usually Critical Ischemia)

       

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    Duplex Ultrasound

    • Poor for anatomy.
    • Good for flow, can get flow velocities and localize disease.
    • Can get ABIs for all over the legs and localize disease.

     

    Angiogram

    • Contast dye through femoral artery, Xrays.
    • Useful if revascularization is considered

    Other

    • CT angio
    • MR Angio

    Treatments

    • Risk Factor management
      • Quit smoking
      • ECASA (ASA - enteric coated) 81mg po od
        Or clopidogrel
      • High dose statin
      • If DM: good glycemic control
      • Exercise: 20min 3x/week
      • Lipid management: LDL < 2-3.5 TC/HDL >4??
    • Treating Pain
      • Cilostazole (in trials improved walking distance)
      • Pentoxyfylline (questionable benefit in trials)
    • Invasive:
      • Angioplasty +/- stent
      • Bypass Surgery
        • Aortho-bifemoral bypass
        • Axillary bifemoral
        • Femoral-popliteal (for SFA disease)
        • Femoral-tibial
        • femoral-dorsalis pedis.
        • popliteal- dorsalis pedis

     

     

     

    Acute Ischemia

    • Pain is SEVERE, VERY SEVERE, morphine will not cut it
    • Symptoms: Pain, Palor, pulselessness, polar (cold), parasthesiaparalysis (bold - late findings high risk of limb loss)
      • If Movement and senslation lost - poor prognosis, requires treatment NOW.
    • Differential:
      • Embolus (most common)
      • Thrombosed popliteal aneurism.
      • Acute thrombosis on chronic.
      • Trauma
    • Anticoagulation (Heparin)
      • Stops coagulation, helps thrombolysis.
      • May dissolve small clots, rarely adequate tx.
    • If Embolus:  Thrombolysis +/- angioplasty
      • Catheter into artery, inject throbolysis (i.e. tPA) and heparin.
      • Risk of bleeding + stroke.
    • Percutaneous mechanical thrombectomy
      • High velocity saline pumped into tip of catheter (endovascular)
      • "venturi" effect, breaks up clot.
      • Some clots do not fragment.

    Venous Insufficiency

    • Results from persistent venous hypertension caused by venous incompetence or occlusion.
    • Manifestations: (chronic)
      • Edema
      • Skin hyperpigmentation
      • Stasis dermatitis
      • Varicose veins
      • Lipodermatosclerosis (Like constricting band in lower legs - "champagne bottle")
      • Cellulitis
      • Ulceration (Ankles)
    • Diagnosis: Based on history and examination (avoid biopsy - due to non-healing ulcers)
    • Management:
      • Reduce venous hypertension
        • Leg elevation and
        • Compression therapy.
          • Avoided in those with peripheral arterial disease and decompensated heart failure.
          • Knee-high compression stockings with pressures 20-40 mmHg
      • Medicaiton Review (Calcium channel blockers and thiazolidinediones, can cause dependent edema)

     

    Aortic Dissection

    • Type A Aortic Dissections require SURGERY
      • Bicuspid aortic valve pre-disposes to this ("aortopathy").
    • Type B Dissections are divited into:
      • Complicated
        • Defined by renal/mesenteric/peripheral ischemia.
        • Needs emergency surgery (fenestration).
      • Uncomplicated
        • 90% 30 day mortality
        • IV BP and HR control... targets: (to reduce shear stress on dissection)
          • BP < 120
          • HR < 60
      • Possible to stent
    • Investigations:
      • D-dimer value below 0.5 µg/mL (0.5 mg/L) measured within the first 24 hours of symptoms had a NPP of 95% for acute aortic dissection.  (International Registry of Acute Aortic Dissection)
      • Contrast enhanced CT Scan (1st line) [Sn 94%, Sp 87%]
      • If CT not available (i.e. renal function, cannot transport patient, etc..)
        • --> Do TEE (Sn 98%, Sp 77%)
      • MRI --> best test [Sn 98%, Sp, 98%]
      • Aortography [Sn 88, Sp 94]
      • For pre-operative setting: image entire aorta
    • Surveillance:
      • Post-Repair: q3-5y with CT or MRI (entire aorta)
    • BP control Drugs:
      • nitroprusside (0.2 mcg/kg/min titrate up for BP)
        • Must combine with rate control agent, otherwise tachycardia can increase cardiac output, shear forces, cause more dissection.
        • esmolol 500 mcg/kg bolus + 50 mcg/kg/min infusion (increase by 25 ucg/kg/min q5m to heart rate)
          OR:
      • Labetalol 20mg IV over 2min then 1-2 mg/min to desired effect. (max cummulative 300mg)
        • Nice b/c has alpha and beta activity.
      • Type B Aortid dissection rarely require surgery.  
        • Indications for surgery are: malperfusion syndromes and significant aneurysmal dilatation.
    • Source: CCS guidelines 2009

    Thoracic Aortic Disease (Prevention)

    • BP Targets:
      • Normally < 140/90
      • Diabetes < 130/80 (same as CHEP guidelines)
    • Marfan's Syndrome:
      • Use B-Blocker and/or ARB (to reduce aortic dilation)
    • Avoid strenuous resistance and isometric exercise
    • No driving if:
      • Ascending aorta > 6.0cm
      • Descending aorta > 6.5cm
      • (For commercial driving, decrease by 0.5cm each limit)
      • After aortic repair: no private driving for 6 weeks, no commercial driving for 3 mo

     

    Marfan's Syndrome

    (Source: MKSAP 16)

    • Diagnosis: Dependent on classic signs:
      • Opthalmologic
      • Cardiovascular
      • MSK
    • Diagnostic Criteira:
      • Diagnostic Criteria for Marfan's Syndrome (See revised 1996 Ghent criteria)

        (Check Criteria, but below is a very roughs summary)

        • 4/8 of MSK features (need to confirm)
          • Arm Span > Pts height
          • Arachnodatyly (long digits)
          • Pectus excavatum (rib overgrowth)
          • Scoliosis
          • Micrognathia
          • High Arched Palate
          • Ligamentous Laxity
          • ...
        • Ectopia Lentis
        • Aortic Root Dilatation
        • Lumbosacral Dural Ectasia (diagnosed with imaging)
        • Family History

        Vascular EDS:

        - Aneurysmal dilation of blood vessels, ligamentous laxity, and often thin translucent skin

        (DO NOT have ectopia lentis, or MSK abnormalities)

    • Genetic screening for Marfan's Syndrome to provide counselling and know nature of disease.
    • At diagnosis:
      • Echo to image aortic root
      • Repeat echo in 6 mo to determine rate of progression
        • If stable, image annually
        • If progresses > 45mm --> frequent screening

    Source: CCS guidelines 2009

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