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High PVR and Pediatric Heart Transplantation: Right Heart Should Not Be Left Out!


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Shriprasad Deshpande, MD, MS
Emory University
Atlanta, GA, USA
Desphandes@kidsheart.com



Elevated of pulmonary vascular resistance is considered a relative contraindication for heart transplantation. As is true with other circumstances such as ABO incompatibility or very high PRAs, elevated PVR continues to be a moving target.

The elevation of PVR is thought to be a remodeling response to chronic elevation of LV end-diastolic pressure and low cardiac output. In patients with congenital heart disease, additional factors such as Fontan physiology, abnormal pulmonary vasculature and chronic exposure to left-to-right shunts contributions to high PVR.

Impact of elevated PVR especially on the right ventricle post heart transplantation is a critical area of concern that is under investigated. Additionally, increasing burden of adult congenital patients may substantiate this problem further.

The initial UNOS analysis by Davies et al (2008) [1] identified a PVR of > 6 WU along with elevated creatinine and high PRAs as risk factors for mortality. Over the last 5 years, there have been few additional reports outlining pediatric experience with elevated PVR and outcomes in pediatric heart transplantation. In 2010, Daftari et al [2] reported outcomes in 7 patients with elevated PVR (mean 11.0 WU) that were treated with sildenafil or bosentan preoperatively and managed with sildenafil, iloprost and inhaled nitric oxide postoperatively. They report 100% survival at one year. However, a report from 2011 by Ofori-Amanfo [3] concluded that patients with elevated PVR, especially those with poor response to acute vaso-dilatory therapy had significantly higher incidence of RV failure and mortality compared to those with normal PVR. Singh et al (2014)[4] report experience of treating post-transplant high PVR patients with sildenafil. 24 patients treated with sildenafil demonstrated an improvement in PVR, mean PA pressures and RV function with therapy. Overall, although there is sparse data, early and aggressive treatment of elevated PVR pre-and post heart transplantation seems to improve outcomes. Similarly, close monitoring of the right ventricular function as well as preemptive and early therapy of right ventricular failure is critical in avoiding morbidity and mortality related to RV failure post-transplantation. The current update to the ISHLT guideline (2016) [5] identifies the need for thorough evaluation of PVR in pediatric patients especially those with congenital heart disease. The guidelines emphasize that response to acute vasodilatory testing to differentiate between 'reversible' vs 'irreversible' PVR may be critical. Additionally, the role of ventricular assist devices in assessing chronic remodeling and reversibility of PVR needs significant research in pediatric patients. As a community, establishing guidelines for pediatric transplant candidacy in the setting of high PVR, better data regarding outcomes, thresholds for early initiation of therapy will help improve management and outcomes of these patients. ■

Disclosure Statement: The author has no conflicts of interest to disclose.


References:

  1. Davies RR, Russo MJ, Mital S, Martens TM, Sorabella RS, Hong KN, et al. Predicting survival among high-risk pediatric cardiac transplant recipients: an analysis of the United Network for Organ Sharing database. J Thorac Cardiovasc Surg. 2008;135(1):147-55, 55.e1-2.
  2. Daftari B, Alejos JC, Perens G. Initial Experience with Sildenafil, Bosentan, and Nitric Oxide for Pediatric Cardiomyopathy Patients with Elevated Pulmonary Vascular Resistance before and after Orthotopic Heart Transplantation. J Transplant. 2010;2010:656984.
  3. Ofori-Amanfo G, Hsu D, Lamour JM, Mital S, O'Byrne ML, Smerling AJ, et al. Heart transplantation in children with markedly elevated pulmonary vascular resistance: impact of right ventricular failure on outcome. J Heart Lung Transplant. 2011;30(6):659-66.
  4. Singh RK, Richmond ME, Zuckerman WA, Lee TM, Giblin TB, Rodriguez R, et al. The use of oral sildenafil for management of right ventricular dysfunction after pediatric heart transplantation. Am J Transplant. 2014;14(2):453-8.
  5. Mehra MR, Canter CE, Hannan MM, Semigran MJ, Uber PA, Baran DA, et al. The 2016 International Society for Heart Lung Transplantation listing criteria for heart transplantation: A 10-year update. J Heart Lung Transplant. 2016;35(1):1-23.



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