Managing pulmonary hypertension in heart transplantation: meeting the challenge.

The most common measurements of pulmonary hypertension include systolic and mean pulmonary artery pressures, PVR, and transpulmonary gradient. Pulmonary artery pressures greater than 50 mm Hg, PVR greater than 6 Woods units, and transpulmonary gradient greater than 15 mm Hg that are unresponsive to optimal vasodilators are contraindications to orthotopic heart transplantation. Therapies used to reduce PVR in the cardiac catheterization laboratory include high-flow oxygen; sublingual nitroglycerin; and intravenous inotropic agents, vasodilators, and selective pulmonary vasodilators. Systemic hypotension may be an undesirable side effect of vasodilators. Inhaled agents such as nitric oxide and prostacyclin are specific to the pulmonary vasculature and reduce PVR without causing systemic hypotension. All pharmacological therapies used to optimize pulmonary hemodynamics before transplantation can be used during transplantation in patients who are at high risk for acute right ventricular failure and death after orthotopic heart transplantation because of elevated pulmonary hemodynamic values. Use of larger donor hearts for patients with elevated PVR and referral for heart-lung transplantation are potential treatment options. A heterotopic heart transplantation might also be attempted. However, because of the poor success with heterotopic transplantation, other options such as treatment with inhaled pulmonary vasodilators show much more promise and are associated with long-term survival after transplantation. Finally, nursing knowledge and implementation of transplantation protocols are essential for continued assessment and management of candidates for heart transplantation who are cared for in the intensive care or coronary care unit.

The preparation of fully active chymopapain free of contaminating proteinases.

Chymopapain (EC 3.4.22.6) was purified from commercially available dried latex of papaya (Carica papaya) by extraction at acidic pH, cation-exchange chromatography and active site-directed affinity chromatography on immobilized alanyl-phenyl-alaninaldehyde semicarbazone, with elution by mercuric chloride. The product was found by immunoassay to be essentially free of the other cysteine proteinases from papaya, including papaya proteinase IV, and was fully active. The rate of alkylation of the active site cysteine of chymopapain by iodoacetate was found to be sufficiently rapid and selective for this reagent to be used as an active-site titrant.