I thank Dr. Raja for an excellent appraisal of the role of sildenafil (Viagra; Pfizer Laboratories, New York, NY) in the management of rebound pulmonary hypertension after withdrawal of inhaled prostacyclin, as highlighted in our recent case report.1Dr. Raja has correctly highlighted that sildenafil is an alternative to iloprost in this setting.2–7Our discussion of iloprost in the case report focused on its advantages over inhaled prostacyclin in the withdrawal of inhaled pulmonary vasodilator therapy. The pharmacokinetics of iloprost highlight a limitation of inhaled prostacyclin, namely its short half-life, that may facilitate serious rebound pulmonary hypertension.

However, this discussion was by no means intended to minimize the role of alternative approaches to the management of rebound pulmonary hypertension. As emphasized, a tiered multimodal therapeutic approach to pulmonary hypertension is essential for successful management.1,8,9Indeed, this multimodal therapeutic approach to this clinical scenario not only includes sildenafil but also extends beyond this agent. The withdrawal of inhaled pulmonary vasodilators with a short half-life (nitric oxide, prostacyclin) should be managed in the setting of optimized ventilation, and where required, sufficient supplemental pulmonary vasodilator, whether inhaled, intravenous, or oral. There is a wide selection of possible agents that may be administered alone or in synergistic combination.8,10The choice of regimen should also take into account drug availability, drug familiarity, and patient idiosyncrasies.

In summary, rebound pulmonary hypertension with withdrawal of nitric oxide or prostacyclin should be approached in a tiered multimodal fashion. Although sildenafil is eminently suitable, it is but one of a possible menu of pharmacologic choices.

Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania. yiandoc@hotmail.com

Augoustides JG, Culp K, Smith S: Rebound pulmonary hypertension and cardiogenic shock after withdrawal of inhaled prostacyclin. Anesthesiology 2004; 100:1023–5
Atz AM, Lefler AK, Fairbrother DL, Uber WE, Bradley SM: Sildenafil augments the effect of inhaled nitric oxide for postoperative pulmonary hypertensive crises. J Thorac Cardiovasc Surg 2002; 124:628–9
Atz AM, Wessel DL: Sildenafil ameliorates effects of inhaled nitric oxide withdrawal. Anesthesiology 1999; 91:307–10
Michelakis E, Tymchak W, Lien D, Webster L, Hashimoto K, Archer S: Oral sildenafil is an effective and specific pulmonary vasodilator in patients with pulmonary arterial hypertension: Comparison with inhaled nitric oxide. Circulation 2002; 105:2398–403
Stocker C, Penny DJ, Brizard CP, Cochrane AD, Soto R, Shekerdemian LS: Intravenous sildenafil and inhaled nitric oxide: A randomised trial in infants after cardiac surgery. Intensive Care Med 2003; 29:1996–2003
Bharani A, Mathew V, Sahu A, Lunia B The efficacy and tolerability of sildenafil in patients with moderate-to-severe pulmonary hypertension. Indian Heart J 2003; 55:55–9
Ghofrani HA, Wiedemann R, Rose F, Schermuly RT, Olschewski H, Weissmann N, Gunther A, Walmrath D, Seeger W, Grimminger F: Sildenafil for treatment of lung fibrosis and pulmonary hypertension: a randomised controlled trial. Lancet 2002; 360:895–900
Augoustides JG, Ochroch EA: Perioperative use of nitric oxide in cardiothoracic anesthesia and intensive care, Progress in Anesthesiology. Vol XV. Chapter 7. San Antonio, Texas, Dannemiller Foundation, 2001, pp 115–24
San Antonio, Texas
Dannemiller Foundation
Augoustides JG, Mancini DJ: Postoperative care of the adult cardiac surgical patient, Progress in Anesthesiology. Vol XVI. Chapter 7. San Antonio, Texas, Dannemiller Foundation, 2002, pp 99–112
San Antonio, Texas
Dannemiller Foundation
Lowson S: Inhaled alternatives to nitric oxide. Anesthesiology 2002; 96:1504–13