A. Overview of Hemophilias (Table 1, Ref [2])

1. Inherited deficiencies of coagulation factors
2. Associated with bleeding disorders
3. Family history of hemophilia is absent in ~30% of newly diagnosed patients
4. Autosomal recessive (AR) or X-linked recessive (XL) inheritance

   Deficiency	Incidence	Chromosome	Inheritance
   Fibrinogen (Factor I)	1:1 million	4	AR
   Prothrombin (Factor II)	1:2 million	11	AR
   Factor V	1:1 million	1	AR
   Factor VII	1:500,000	13	AR
   Factor VIII (Hemophilia A)	1:10,000	X	XL
   Factor IX (Hemophilia B)	1:60,000	X	XL
   Factor X	1:1 million	13	AR
   Factor XI	1:1 million	4	AR
   Factor XIII	1:1 million	6,1	AR
   Von Willebrand's Disease	1:100-1:500	12	AR

B. Hemophilia A

1. Congenital and Acquired forms occur
2. Congenital Deficiency of Factor VIII
   1. X Linked Gene so that nearly all patients are male
   2. 1 per 5000 male births
   3. About 30% of cases are new (spontaneous) mutations; 70% are familial
   4. Carried asymptomatically by females
   5. Suspect in any male patient with history of excessive or spontaneous bleeding
3. Acquired Hemophilia A [3]
   1. Relatively rare condition
   2. Usually occurs in older persons, mean age 60s
   3. Normal intrinsic production of FVIII occurs
   4. Autoantibodies develop spontaneously which neutralize FVIII
   5. Does not include true Hemophilia A patients who mount immune response to Factor VIII
   6. Idiopathic spontaneous form occurs in ~1:1,000,000 persons per year
   7. Underlying disease found in ~50% of patients
   8. Rheumatoid arthritis or systemic lupus erythematosus may be present
   9. Associated with leukocyte disorders - especially CLL, dysgammaglobulinemias
4. Properties of FVIII
   1. Intrinsic pathway factor, activated by Factor IXa
   2. Serum t1/2 ~12-24 hours (with normal vWF levels, see below)
   3. FVIII is a 280K heterodimeric enzyme, carried in serum by vWF (see below)
5. Factor VIII Deficiency Levels
   1. Severe: Clotting Factor Level <0.01 IU/mL
   2. Moderate: Factor level 0.01 to 0.05 IU/mL
   3. Mild: 0.05-0.40 IU/mL
   4. Normal levels ~1 IU/mL
6. Symptoms of Severe Disease
   1. Spontaneous bleeding into joints or muscles, 1-2 episodes per week
   2. Intracranial hemorrhage
   3. Severe post-traumatic bleeding
7. Symptoms of Mild or Moderate Disease
   1. Low risk of spontaneous hemorrhage
   2. Excessive bleeding post-surgery or trauma
   3. Hemearthroses may occur, even in mild disease [4]
8. Laboratory Abnormalities
   1. Screening: APTT prolongation; however, this is not always present
   2. vWF and ristocetin cofactor levels are normal
   3. Confirmation: specific factor VIII level determination (antibody based)
   4. Mixing study required to demonstrate acquired hemophilia A
9. Factor VIII Gene Therapy [5]
   1. Excellent disease for gene therapy
   2. Low levels (>4% of normal) of Factor VIII can be very beneficial
   3. Factor VIII transferred ex vivo to fibroblasts with reimplantation
   4. Reimplanted cells expressed Factor VIII for ~10 months
   5. Increased Factor VIII led to reduced bleeding and/or use of exogenous Factor VIII

C. Hemophilia B

1. Also called Christmas Disease
2. Congenital Deficiency of Factor IX
   1. X Linked Gene so that nearly all patients are male
   2. 1 per 30,000 male births
   3. About 30% of cases are new (spontaneous) mutations; 70% are familial
   4. Carried asymptomatically by females
   5. Suspect in any male patient with history of excessive or spontaneous bleeding
   6. Cannot distinguish from Factor VIII deficiency based on clinical grounds
3. Properties of Factor IX
   1. Intrinsic pathway, activated by Factor XIa
   2. Serum t1/2 ~ 24 hours
4. Screening Laboratory Test: APTT elevation in most patients
5. Confirmation Test: Specific factor level determination

D. Von Willebrand's (vWF) Disease [6]

1. Properties of vWF
   1. vWF is Factor VIII carrier protein coded on chromsome 12p
   2. This protein is very large and exists in multimers that may be >20,000 kD in size
   3. vWF increases serum half life (t1/2) of Factor VIII
   4. Interacts with platelets allows normal binding of platelets to endothelium
   5. Normal vWF forms large multimers; most abnormal variants form reduced multimers
   6. Autosomal gene
2. vWF Disease worldwide is ~2-10 per 1000, including mild cases (USA has low rate)
3. Overall Symptoms of vWF Antigen Deficiency
   1. Often mild with few symptoms in normal situations
   2. May present in surgery or trauma with increased bleeding
   3. Platelet dysfunction is major manifestation: nosebleeds, gum bleeding, petechiae
   4. Menorrhagia, gastrointestinal hemorrhage, may also occur
4. Classification of vWF Disease
   1. Hereditary forms are types 1-3
   2. Aquired vWF disease
5. Type 1 vWF Disease
   1. Partial quantitative deficiency of vWF
   2. Mild disease, ~70% of cases
   3. 5-30% of normal plasma levels of vWF (5-30 IU/dL)
   4. typically transmitted as autosomal dominant trait in heterozygous state
6. Type 2 vWF Disease
   1. Qualititative abnormalities of vWF
   2. Typically autosomal dominant
   3. ~20% of cases of vWF Disease
   4. Subtypes 2A, 2B, 2M, 2N
   5. Type 2A: selective absence of large multimers of vWF; defective platelet vWF functions
   6. Type 2B: heightened platelet vWF functions associated with lack of large vWF multimers
   7. Type 2M: defective platelet dependent vWF effects; normal levels of large multimers
   8. Type 2N: defective vWF binding to Factor VIII
7. Type 3 vWF Disease
   1. Complete deficiency of vWF
   2. ~5% of all cases of vWF disease
   3. Autosomal recessive
8. Acquired vWF Disease [7]
   1. Usually associated with dysproteinemias or systemic lupus
   2. Acquired Type 2A vWF syndrome associated with severe aortic stenosis [9]
   3. Hayde's syndrome is aortic stenosis, gastrointestinal angiodysplasia, type 2A vWF
   4. Hypothyroidism can lead to decreased synthesis of vWF
9. Laboratory Diagnosis
   1. No single test is absolutely reliable to rule out vWF Disease
   2. Normal APTT and/or PT do not rule out disease
   3. Possible APTT elevation because vWF is a carrier protein for Factor VIII
   4. Four relatively simple tests required for diagnosis:
   5. Bleeding Time: increased due to platelet inefficiency in binding to vessel wall
   6. Direct measurement of vWF protein (antigen) levels (immunological assay)
   7. Direct measurement of Factor VIII antigen levels
   8. Measurement of vWF platelet aggregation in presence of ristocetin (vWF function assay)
   9. Functional assay is so-called "ristocetin cofactor activity" where ristocetin increases the binding of vWF to platelets through platelet membrane glycoprotein Ib-alpha
10. Treatment
    1. For Type 1 (mild) disease, desmopressin is very effective
    2. Desmopressin (1-deamino-8-D-arginine vasopressin) binds to V2 vasopressin receptors and transiently increases both factor VIII and vWF levels
    3. Desmopressin dose is 0.3µg/kg by continuous infusion for 30 minutes
    4. Desmopressin also available as sc injection (0.3µg/kg) or fixed dose nasal inhalation
    5. For Types 2 and 3, vWF replacement products are required
    6. Humate-P® contains larger amounts of vWF than Factor VIII
    7. Antifibrinolytic agents such as e-aminocaproic acid (50-60mg/kg q4-6 hours) usually given as adjuncts to above therapy
    8. Treatment usually only given before surgery or dental procedures, or post-trauma, or prior to delivery

E. Routine Screening for Coagulopathy

1. Standard Clotting Times: PT / PTT
2. If PT or PTT elevated should prompt a determination of Thrombin Time (TT)
   1. Thrombin time abnormal: heparin effect or fibrinogen deficiency
   2. Thrombin time normal: clotting factor deficiency or coagulation inhibitor
3. Mixing study is performed if normal thrombin time is present
   1. Test serum is mixed with normal serum and PTT or PT is measured
   2. PTT/PT Time Normal in mixing study suggests Factor Deficiency
   3. PTT/PT Time Abnormal in mixing study suggests coagulation Inhibitor is present
4. Typical Coagulation Inhibitors
   1. Anticardiolipin and Antiphospholipid Antibodies
   2. Lupus Anticoagulant
   3. Acquired specific factor inhibitors including anti-factor VIII or anti-vWF antibodies
   4. Acquired factor VIII inhibitors are antibodies (Abs) usually of IgG type
   5. IgG anti-Factor VIII Abs can stimulate the proteolysis of Factor VIII in serum [10]
5. Russel Viper Venom Time (RVVT) test
   1. RVVT is used to analyze plasma for presence of inhibitors of coagulation
   2. RVVT is prolonged with lupus anti-coagulant and anti-phospholipid antibodies
6. Factor Deficiency
   1. Factor VIII is most common symptomatic deficiency (Hemophilia A)
   2. Factor XI, XII deficiencies fairly common, often with minimal symptoms
   3. Factor IX deficiency is uncommon but may be severe
   4. vWF Disease requires evaluation of Factor VIII, ristocetin cofactor activity, vWF antigen
   5. Factor V, VII, or X deficiencies are very rare
   6. Vitamin K deficiency (malnutrition, bacterial overgrowth) - Factors II, VII, IX, X
   7. Hepatic Failure associated with similar deficiencies - Factors II, VII, IX, X
7. Bleeding Time
   1. Best test for evaluation of platelet function
   2. Bleeding time is also prolonged in vWF deficiency, either genetic or acquired

F. Presentation of Hemophilia

1. Hemarthrosis: bleeding into joint capsule
2. Synovial trauma with chronic synovitis
3. Cartilage destruction leads to "frozen" joint (very painful)
4. Muscle atrophy
5. Symptoms
6. Prickling sensation, pain
7. Stiffness, reduced motion
8. Tenderness
9. Swelling
10. Hematoma
11. Muscle Bleed leading to compartment syndrome
12. Mortality
    1. Intracranial Hemorrhage
    2. Retroperitoneal hemorrhage

1. Factor concentrate or recombinant material (preferred)
2. Recombinant Products
3. DDAVP: slows bleeding, especially in vWF disease and uremia (platelet dysfunction)
4. Danazol: can increase platelet count
5. e-Aminocaproic acid (Amikar®): plasmin inhibitor, good for mucus membrane bleeding

B. Factor Concentrate Usage

1. Desire >40% of normal levels for mucous membrane and joint bleeding
2. Desire >75% of normal levels for intracranial and retroperitoneal hemorrhage
3. At least two viral inactivation steps used in production of all factor concentrates

C. Recombinant Factors [11]

1. Recombinant Factor VIII (rFVIII) for treatment of patients with hemophilia A
2. All patients previously untreated
3. Essentially no side effects, no treatment failures of recombinant protein
4. Episodic versus Prophylactic Treatment
   1. Arthropathy is most common complication of severe hemophilia
   2. Regular infusions of rFVIII or episodic (around hemearthrosis) treatments are used
   3. Regular (prophylactic) infusions rFVIII significantly reduces joint damage compared with episodic treatment [14]
   4. Therefore, regular infusions of rFVIII should be given to all severe hemophilia A patients
5. ~20% of hemophilia A patients develop inhibitors (anti-FVIII antibodies)
   1. These antibodies may cross react with porcine FVIII
   2. The antibody titers may decrease between factor infusions
   3. May require desensitization (tolerance) or immunosuppressive therapy
   4. Plasmapheresis may be required in emergent situations
6. Recombinant Factor IX is now available (made with no human or animal protein)
7. Recombinant factors are more expensive (and in shorter supply) than factor concentrates

D. Treatment of Patients with Anti-Factor VIII Abs

1. Various factor preparations are available for bypassing anti-Factor VIII Abs [8]
   1. Porcine Factor VIII
   2. Inhibitor Bypass activities - usually patients cross reactive inhibitors (FIBA)
   3. Activated Factor VII (F VIIa) - probably the most effective and safe overall
   4. Activated Factor IX (F IXa) or a
2. None of these activities are as effective as Factor VIII itself
3. FVIIa is recommended in patients with:
   1. Life-threatening hemorrhage
   2. Major surgery

E. Treatment of Acquired Hemophilia [3]

1. Treatment divided between inducing hemostasis and treating underlying condition
2. Inducing Hemostasis
   1. High doses of FVIII may be required (~ 30% of normal) to induce hemostasis
   2. Porcine FVIII may be used, as described above
   3. Prothrombin complex concentrate
   4. Recombinant Activated Factor VII (rFVIIa)
   5. Intravenous DDAVP (Desmopressin)
3. rFVIIa (NovoSeven®) [13]
   1. Labelled for treatment of bleeding episodes in hemophilia patients with inhibitors
   2. rFVIIa is inactive until it reaches site of injury and binds tissue factor, activated platelets
   3. Has been used very successfully to stop bleeding from trauma or surgery
   4. Generally safe with no clear increase risk of venous thrombosis or hypercoagulability
   5. Good controlled trials have not been conducted
4. The following treatments should be considered for reducing anti-FVIII Ab levels
5. Immunosuppressive Agents
   1. Glucocorticoids alone are rarely effective
   2. Oral cyclophosphamide with high dose glucocorticoids can induce lasting remissions [12]
6. Unclear if FVIII infusions are required for inhibitor reduction in acquired hemophilia
7. Plasmapheresis or exchange ± Ig replacement can be used in emergent situations
8. In setting of SLE, aggressive treatment of disease can reduce inhibitors
9. Treatment of underling lymphocyte dysfunction can lead to resolution
10. Acquired vFW deficiency is treated with similar agents, attend to underlying disease
11. Valve replacement with good patient-valve match reverse aortic stenosis vFW disease [9]

F. Complications

1. Compartment syndrome: treated by immediate fasciotomy (release)
2. Intracranial Hemorrhage - rapid concentrate infusions and neurosurgical evaluation
3. Thrombosis
   1. Can occur particulary during infusions of anti-hemophilic factors
   2. Factor infusion should be discontinued
4. In pregnant patients, delivery can be vaginal with careful obstetrics
5. Avoid
   1. Aspirin should never be used in hemophiliacs
   2. Some NSAIDs (particularly COX-2 specific) may be okay short term
   3. Addictive pain medications
6. Hepatitis C Virus (HCV) and HIV infections are major risks
   1. Recombinant FVIII eliminates risks
   2. Recombinant FIX is now available
   3. HIV risk now essentially zero
   4. HCV risk is now exceedingly low
7. HCV in Hemophilia Patients
   1. Majority of persons over age 18 with hemophilia are HCV positive
   2. Interferon alpha treatment for chronic HCV does not increase anti-FVIII Ab
8. Development of factor inhibitors (see above)

References

1. Bolton-Mags PHB and Pasi KJ. 2003. Lancet. 361(9371):1801
2. Mannucci PM and Tuddenham EGD. 2001. NEJM. 344(23):1733
3. Bossi P, Cabane J, Ninet J, et al. 1998. Am J Med. 105(5):400
4. Ewenstein BM and Van Cott E. 1998. NEJM. 338(8):532 (Case Record)
5. Roth DA, Tawa NE Jr, O'Brien JM, et al. 2001. NEJM. 344(23):1735
6. Mannucci PM. 2004. NEJM. 351(7):683
7. Sadler JE. 2003. NEJM. 349(4):323
8. Stroncek DF and Rebulla P. 2007. Lancet. 370(9585):427
9. Vincentelli A, Susen S, Le Tourneau T, et al. 2003. 349(4):343
10. Lacroix-Desmazes S, Bayry J, Misra N, et al. 2002. NEJM. 346(9):662
11. Cohen AJ and Kessler CM. 1995. Am J Med. 99(6):675
12. Shaffer LG and Phillips MD. 1997. Ann Intern Med. 127(3):206
13. NovoSeven for Non-Hemophilia Hemostasis. 2004. Med Let. 46(1181):33
14. Manco-Johnson MJ, Abshire TC, Shapiro AD, et al. 2007. NEJM. 357(6):535