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Organ Transplantation, 2nd edition, edited by Frank P. Stuart, Michael M. Abecassis and Dixon B. Kaufman. ©2003 Landes Bioscience.

are used to obtain the following hemodynamic measurements as obtained by pulmonary artery catheterization. The pulmonary capillary wedge pressure should be < 15 mm Hg, the systemic vascular resistance < 1200 dynes/s/cm2, the right atrial pressure < 8 mm Hg and the systolic blood pressure > 80 mm Hg. Conversion from intravenous medications to oral vasodilators and diuretics may then be feasible. Additional medications such as hydralazine, beta-blockers, amiodarone, anticoagulants and ultrafiltration may be useful as a next line of therapy or to stabilize the situation. If intravenous inotropic support is required, particularly if the patient then becomes dependent on such medications as dobutamine, or milrinone, then mechanical ventricular assist devices may be used as a next line of therapy. Mechanical assistance is particularly valuable to prevent irreversible failure in other organ systems. The simplest form of mechanical support is an intraaortic balloon pump (IABP). The intraaortic balloon pump may be very useful but should be considered as temporary support. This becomes an issue as patients supported on inotropes or with the IABP have experienced increasingly long waits on the transplant list. The indications for mechanical support are a cardiac index less than 2.0, mean arterial pressure less than 60 mm Hg and worsened hepatic and/or renal function. If a patient is unable to be weaned from an IABP in two to three weeks, then ventricular assist device (VAD) (see Table 11.1) or total artificial heart (TAH) may be indicated.

At present several total artificial heart devices are being investigated, including the Penn State heart, and the Abiomed TAH. Several axial flow pumps to be used as VAD and TAH are in development. Additional surgical approaches fall short of transplantation, such as cardiomyoplasty, which entails the wrapping of the latis-simus dorsi muscle around the heart after the muscle has been preconditioned by artificial stimulation. Another procedure, based on the principles of volume reduction to improve stroke work and decrease wall tension, is the Dor procedure. This operation entails resection of the left ventricle, frequently with mitral valve replacement or repair. This is primarily reserved for patients with largely dilated left ventricles. While the early results are encouraging, the incidence of sudden death post procedure remains high.

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