Authors: Greesha S. Pednekar, MD - Children’s Memorial Hermann Hospital, University of Texas Health Science Center at Houston, TX and Destiny F. Chau, MD - Arkansas Children’s Hospital /University of Arkansas for Medical Sciences, Little Rock, AR
A 2-year-old girl with a history of dilated cardiomyopathy and subsequent left ventricular assist device implantation has persistent right ventricular failure supported with high doses of inotropic medications and inhaled nitric oxide. According to the Pedimacs registry, which of the following percentages MOST accurately reflects the approximate rate of right ventricular failure in the first month after left ventricular assist device placement?
EXPLANATION
Patients undergoing left ventricular assist device (LVAD) placement are at risk of right ventricular (RV) failure. Persistent RV failure is associated with increased morbidity and mortality, including multi-organ dysfunction, which may jeopardize transplant candidacy. Anticipation, prevention, and early detection of RV failure is imperative in LVAD planning and management.
An analysis of the largest pediatric VAD registry, called the Pedimacs registry, by Simpson et al demonstrated that 55% of children had RV failure during a time frame between one week to one month after LVAD implantation. An additional 25% of pediatric patients had RV failure between one and three months after LVAD placement. Factors associated with RV failure were younger age, lower weight, INTERMACS profile 1, chemical paralysis, and a pulsatile flow device. In addition, RV failure was associated with an increased risk of death during device support at time points of greater than one month (hazard ratio 3.2, 95% CI 1.4-7.7, p = 0.007) and greater than three months after LVAD insertion (hazard ratio 6.9, 95% CI 2-23.1, p = 0.002). In this analysis, RV failure was defined as prolonged inotrope use or subsequent need for right VAD.
Deterioration of RV function after LVAD implantation can occur due to a number of reasons, including the following:1) Increased cardiac output results in increased systemic venous return and acute increases in RV preload, myofibril stretch, wall tension and myocardial oxygen demand, which may not be well tolerated under circumstances of depressed RV function; 2) LV unloading causes a leftward shift of the interventricular septum, thereby distorting RV geometry and interfering with the RV free wall contractility and worsening tricuspid regurgitation; 3) Apical LVAD implantation can impede the normal twisting motion of the RV, thereby impeding RV contractility and; 4) Intraoperative myocardial ischemia may further worsen RV function.
After LVAD placement, anticipation of and preparation for RV failure during separation from cardiopulmonary bypass is critically important. Support of the RV includes initiation of inhaled nitric oxide, inotropic support, and avoidance of RV distension by excessive volume administration, along with avoidance of hypoxia and hypercarbia. Transesophageal echocardiography may be utilized to assess ventricular function, ventricular volume, and interventricular septal position after VAD placement.
REFERENCES
Simpson KE, Kirklin JK, Cantor RS et al. Right heart failure with left ventricular assist device implantation in children: An analysis of the Pedimacs registry database. J Heart Lung Transplant. 2020;39(3):231-240. doi: 10.1016/j.healun.2019.11.012.
Law SP, Morales DLS, Si MS, et al. Right heart failure considerations in pediatric ventricular assist devices. Pediatr Transplant. 2021;25(3):e13990. doi:10.1111/petr.13990
Horton S, Skiner A, Bacigalupo A, Adachi I, Stayer S, Motta P. Mechanical Circulatory Support. In: Andropoulos D, Mossad E, Gottlieb E, eds. Anesthesia for Congenital Heart Disease. 4th Edition. Hoboken, New Jersey: John Wiley & Sons, Inc.; 2023: 996-1025.
