Implantable devices/implantation therapy

We should note here that there are some special cases for which the use of healthy participants is not justified in early studies. For particularly invasive therapies (for example, implantation of a medical device) or therapies with known toxicity (for example, oncologies) it is not ethical to study healthy participants. The use of healthy participants in early studies may also provide a misleading result for future studies of participants with disease. For example, the maximum tolerated dose of new antidepressants or anxiolytics may differ quite markedly between healthy participants and those with the disease. 

Life sustaining devices provide therapy that keeps a patient alive. An implantable defibrillator is an example of a life sustaining device. Certain cardiac patients experience tachycardia (a very rapid heart beat) or ventricular fibrillation. Either condition limits the ability of the heart to effectively pump blood. Death can result if this type of arrhythmia is sustained and a normal heart rhythm is not restored by a defibrillator. 

Valve Problems. The primary solution to valve problems has been implantable replacement valves. The introduction of these devices necessitates open-heart surgery. There are two types of valves available tissue (porcine and bovine) and mechanical. The disadvantage of tissue valves is that these have a limited life of about seven years before they calcify, stiffen, and have to be replaced. The mechanical valves can last a lifetime, but require anticoagulant therapy. In some patients, anticoagulants may not be feasible or may be contraindicated. Of the valves which require replacement, 99% are mitral and aortic valves. The valves on the left side of the heart are under much greater pressure because the left ventricle is pumping blood out to the entire body, instead of only to the lungs. Occasionally, two valves are replaced in the same procedure. 

The ventricular assist device (VAD) is a surgically implanted pump that reduces or replaces the work of the right, left, or both ventricles. Ventricular assist devices are currently indicated for short-term support in patients refractory to pharmacologic therapies, as long-term bridge therapy (a temporary transition treatment) in patients awaiting cardiac transplant, or in some instances, as the destination therapy (treatment for patients in lieu of cardiac transplant for those who are not appropriate candidates for transplantation).1 The most common complications are infection and thromboembolism. Other... 

More recently, the challenge to formulate with consistency highly potent actives present in diminishingly low concentrations raised the bar for formulations another significant notch. Procedures and devices for safe intravitreal implantation of sustained antiviral medication have grown from the advent of new therapies for a life- and eye-threatening new disease, HIV-AIDS. 

Vancomycin may be considered for prophylactic therapy in surgical procedures involving implantation of a prosthetic device in which the rate... 

Intrathecal therapy may be considered an alternative to destructive neurosurgical procedures. Prior to implantation of a device for chronic intrathecal infusion, patients must show a response in a screening trial. 

The CARE-HF study was a European study of medical therapy alone versus medical therapy with the addition of a CRT pacemaker [119]. A total of 813 patients were enrolled and randomized in a 1 1 ratio prior to device implant, again a true intent-to-treat design. Patients were followed longer than in the COMPANION trial, for a mean of 29.4 months. The primary end point was the time to... 

Current therapies for cartilage reconstruction or replacement include implantation of artificial prosthetic devices [2] and, occasionally, transplantation of... 

Low doses (100-200 mg/d) of amiodarone are effective in maintaining normal sinus rhythm in patients with atrial fibrillation. The drug is effective in the prevention of recurrent ventricular tachycardia. It is not associated with an increase in mortality in patients with coronary artery disease or heart failure. In many centers, the implanted cardioverter-defibrillator (ICD) has succeeded drug therapy as the primary treatment modality for ventricular tachycardia, but amiodarone may be used for ventricular tachycardia as adjuvant therapy to decrease the frequency of uncomfortable cardioverter-defibrillator discharges. The drug increases the pacing and defibrillation threshold and these devices require retesting after a maintenance dose has been achieved. 

The answer to the shortage of hver tissue is to evolve from a dependence on whole and partial organs to the use of hepatic cehs. Ceh therapies range from the injection of ceh colonies with the hope that they wih take up residence and become chnicahy active to the development of implantable or extracorporeal devices. Such approaches must consider both the sources of hepatocytes and stabilization of liver-specific functions. 

Brennan TD, Haas GJ. The role of prophylactic implantable cardioverter defibrillators in heart failure recent trials usher in a new era of device therapy. Curr Heart Fail Rep. 2005 2 40-45. 

Intravenous antibiotics are given before and after the procedure. Endocarditis prophylaxis is recommended for six months. Coumadin type drugs should be administered at least for 45 days after the Watchman implantation procedure with an INR between two and three in combination with 100 mg aspirin. When complete endothelialization is likely with no or only little flowthrough the device, coumadin can be discontinued and clopidogrel 75 mg/day is given until six months follow-up examination. In the absence of thrombus or flow in the appendage at TEE at six months, clopidogrel is stopped and aspirin therapy 100 mg/day is continued indefinitely If thrombus formation is seen, obviously coumadin therapy is restarted. 

Before intervention heparin is administered (100 U/kg) in addition to endocarditis prophylaxis (e.g., cefuroxime, l,5g, i.v.). Endocarditis prophylaxis is repeated afterthe procedure. Aspirin (100mg, p.d.) and clopidogrel (75mg/day, p.o.) are prescribed for six months after implantation. The incidence of thrombus formation varies between devices (50). If thrombus is seen during follow-up, coumadin therapy should be commenced. 

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