Right Ventricle Outflow Tract Obstruction in Adults: A Systematic Review and Meta-Analysis

ABSTRACT Background Right ventricular outflow tract obstruction (RVOTO) is a cause of hemodynamic instability that can occur in several situations including cardiac surgery, lung transplantation, thoracic surgery, and in critically ill patients. The timely diagnosis of RVOTO is important because it requires specific considerations, including the adverse effects of positive inotropes and, depending on the etiology, the requirement for urgent surgical intervention. Methods The objective of this systematic review and meta-analysis was performed to determine the prevalence of RVOTO in adult patients and the distribution of all reported cases by etiology. Results Of 233 available reports, there were 229 case reports or series, four retrospective cohort studies, with one study also reporting a prospective cohort. Out of 291 reported cases of RVOTO, 61 (21%) were congenital, 56 (19%) were iatrogenic and 174 (60%) were neither congenital nor iatrogenic (including intra-cardiac tumour). The mechanism of RVOTO was caused by an intrinsic obstruction in 169 cases (58%) and an extrinsic obstruction in 122 cases (42%). A mechanical obstruction causing RVOTO was present in 262 cases (90%) whereas 29 cases of dynamic RVOTO (10%) were reported. In the 5 included cohorts with a total of 1122 patients, the overall prevalence was estimated to be 4.0% (1-9%). Conclusion RVOTO while rare remains clinically important and, therefore, multicenter studies are warranted to better understand the prevalence, causes and consequences of RVOTO.