Heart valve replacement

Warfarin has been the primary oral anticoagulant used in the United States for the past 60 years. Warfarin is the anticoagulant of choice when long-term or extended anticoagulation is required. Warfarin is FDA-approved for the prevention and treatment of VTE, as well as the prevention of thromboembolic complications in patients with myocardial infarction, atrial fibrillation, and heart valve replacement. While very effective, warfarin has a narrow therapeutic index, requiring frequent dose adjustments and careful patient monitoring.15,29... 

Adverse reactions at therapeutic doses are usually minimal and transient. With long-term use, initial side effects usually disappear. The following reactions were reported in 2 heart valve replacement trials comparing dipyridamole and warfarin therapy to either warfarin alone or warfarin and placebo dizziness, abdominal distress, headache, and rash. 

Cardiopulmonary bypass, with extracorporeal circulation during cardiac artery bypass graft or heart valve replacement surgery, causes transient hemostatic defects in blood cells and perioperative bleeding. The protease inhibitor aprotinin (Trasylol) inhibits kalhkrein (coagulation phase) and plasmin (hbrinolysis) and protects platelets from mechanical injury. The overall effect after infusion is a decrease in bleeding. 

Ginseng (41) (Ginsana ) capsules t.i.d. for 2 wks Male/47 Heart valve replacement Warfarin 5 mg/d for 5 yrs 7.5 mg each Tuesday Diltiazem, nitroglycerin, salsalate Decreased INR (from about 3.3 to 1.5) Not known... 

Indications. Hydroxycoumarins are used for the prophylaxis of thromboembolism as, for instance, in atrial fibrillation or after heart valve replacement. 

Serpins were first identified as a set of proteins able to inhibit proteases. The name serpin is derived from this activity serine protease inhibitors . Heparin is a mixture of polysaccharides that bind to antithrombin in, inducing an allosteric change that greatly enhances its inhibition of thrombin synthesis. Some surgical patients, especially those receiving hip or heart valve replacements and those at risk of ischemic stroke (clots in the brain), are given heparin. 

In a 61-year-old man, who was taking long-term warfarin after a heart valve replacement, the dose of warfarin had to be increased by 40% after the introduction of ribavirin for chronic hepatitis C the inhibition of the effect of warfarin was reproduced on rechallenge (272). 

The more serious events include massive hemorrhage with shock, intracranial bleeding and stroke, and pericardial tamponade. Plasma warfarin levels are not routinely done. The effect of warfarin is best followed by the PT and International Normalized Ratio (INR). Under therapeutic conditions the INR is maintained at 2.0-3.0, except for prophylaxis after artificial heart valve replacement when it may be 2.0-3.5. Specific assays of factor activity can be measured although this is not usually necessary. 

It is used particularly in preventing complications in heart valve replacement. 

Ageno W, Turpie AG, Steidl L, et al. Comparison of a daily fixed 2.5-mg warfarin dose with a 5-mg, international normalized ratio adjusted, warfarin dose initially following heart valve replacement. Am J Cardiol 2001 88(l) 40—4. 

Rahman M, BinEsmael TM, Payne N, et al. Increased sensitivity to warfarin after heart valve replacement. Ann Pharmacother 2006 40(3) 397—401. 

The most widely prescribed anticoagulant in North American is warfarin sodium (Coumadin). It was discovered serendipitously in the early 1940s at the University of Wisconsin after hemorrhagic deaths occurred in cattle eating spoiled sweet clover. Warfarin is approved by the FDA for the prevention and treatment of VTE as well as for the prevention of thromboembolic complications associated with atrial fibrillation, heart valve replacement, and myocardial infarction. Because of its narrow therapeutic index, predisposition to drug and food interactions, and propensity to cause hemorrhage, warfarin requires... 

Operative procedures, such as heart valve replacement, frequently have effects on platelet function and endogenous coagulation factors (137). These effects may result in significant peri- or postoperative bleeding. Aprotinin is a serine protease inhibitor that blocks kallikrein and plasmin and provides some protection to platelets from mechanical injury. The inhibition of fibrinolysis results in profound antihemorrhagic effects (137). Side effects of aprotinin therapy usually are minor, but anaphylaxis has possibly been implicated in a small population (<0.5%). For this reason. 

Phosphocreatine is an effective treatment for acute myocardial infarction and greatly reduces ventricular tachycardia paroxysms [123], It has been prepared in cardioplegic solutions for use during heart valve replacement operations where it significantly reduced ischaemic damage [124]. Phosphocreatinine, although less well investigated, also has a beneficial effect on the ischaemic heart [125,126]. 

Chesebro JH, Fuster V, Elveback LR, McGoon DC, Pluth JR, Puga FJ, Wallace RB, Danielson GK, Orszulak TA, Piehler JM, Schaff HV. Trial of combined warfarin plus dipyridamole or aspirin therapy in prosthetic heart valve replacement danger of aspirin compared with dipyridamole. Am J Cardiol (1983) 51, 1537-41. 

F iore L, Brophy M, Deykin D, Cai f>elleii J, Lau J. The efficacy and safety of the addition of aspirin in patients treated witii oml anticoagulants after heart valve replacement a meta-anal-ysis. Bhod( 99 i) 82 (10 Suppl 1), 409a. 

A 53-year-old woman who had been taking acenocoumarol for 2 years after a heart valve replacement died after a massive brain haemorrhage about 3 weeks after starting to take tamoxifen 20 mg daily for a benign breast condition. ... 

Helmus, M. N., From bioprosthetic tissue engineered constructs for heart valve replacement, in First International Symposium, Tissue Engineering for Heart Valve Bioprostheses, Satellite Symposium of the World Symposium on Heart Valve Disease, Friday, June 11, 1999, Westminster, London (Abstract), pp. 35-36. 

Wilson GF, Courtman DW, Klement P, Lee JM, Yeger H. Acellular matrix a biomaterials approach for coronary artery bypass and heart valve replacement. Ann Thorac Surg 1995 60(2) S353-8. 

Heart valve replacements are considered among the most widely used cardiovascular devices. Traditional choices to the replacement surgeries are the mechanical and bio-prostheses. However, there are risks doing the surgeries, including thrombosis, infection, and limited valve durability. In recent years advances in polymer science have led to an important and new class of artificial heart valves made up of polyurethane-based... 

Fish D (2004), Percutaneous heart valve replacement Enthusiasm tempered . Circulation, 110,1876-1878. 

Lloyd DW and Singer C (2001), Heart valve replacement by textile prosthesis . Textile Asia, October, 16,21-22. 

A 71-year-old man taking stable warfarin therapy 2.25 mg/day) with an INR of 1.8-2.2 after heart valve replacement lost consciousness and had an INR of 5.1 after consuming Sheng-maiyin lOml/day) for 7 days. A CT scan showed a hematoma in the left temporoparietal region. Both warfarin and the herbal product were withheld and he was given intravenous vitamin Ki 40 mg. On the second day a craniectomy was performed to remove the intracerebral hematoma. He remained confused and restless for 2 days but progressively recovered. 

Artificial heart valves Replacement of dysfunctional heart valves... 

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