title: Left ventricular efficiency after ligation of patent ductus arteriosus for premature infants.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the hemodynamic changes in left ventricular function before and after patent ductus arteriosus ligation in premature infants with regard to the energetic efficiency of left ventricular pumping.
  
  
  METHODS
  Thirty-five premature infants who underwent patent ductus arteriosus ligation were enrolled in this study. Left ventricular efficiency was evaluated at 4 points: within 24 hours before patent ductus arteriosus ligation, within 24 hours after patent ductus arteriosus ligation, between postoperative days 2 and 4, and on postoperative day 7. The indices of contractility (end-systolic elastance) and afterload (effective arterial elastance) were approximated on the basis of the systemic blood pressure and systolic or diastolic left ventricular volume. The ratio of stroke work and pressure-volume area, representing the ventricular efficiency, was estimated using the following theoretic formula: the ratio of stroke work and pressure-volume area = 1/(1 + 0.5 ventriculoarterial coupling).
  
  
  RESULTS
  Left ventricular efficiency was transiently deteriorated within 24 hours after patent ductus arteriosus ligation because of the marked increase of the afterload and the slight increase of contraction, and then recovered to preoperation levels by 2 to 4 days after patent ductus arteriosus ligation.
  
  
  CONCLUSIONS
  Analysis of indices representing the afterload, contractility, and energetic efficiency of the left ventricle may provide practical information for the management of premature infants during the postoperative period after patent ductus arteriosus ligation.
authors.affiliation: Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. Electronic address: dadan@pediatr.med.kyushu-u.ac.jp.
authors.forename: Hazumu
authors.initials: H
authors.lastname: Nagata
authors.forename: Kenji
authors.initials: K
authors.lastname: Ihara
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Yamamura
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Tanoue
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Shiokawa
authors.forename: Ryuji
authors.initials: R
authors.lastname: Tominaga
authors.forename: Toshiro
authors.initials: T
authors.lastname: Hara
mesh_terms: D000704:Analysis of Variance; D001794:Blood Pressure; D006348:Cardiac Surgical Procedures; D004374:Ductus Arteriosus, Patent / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D005865:Gestational Age; D006439:Hemodynamics; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008026:Ligation; D008297:Male; D008955:Models, Cardiovascular; D009200:Myocardial Contraction; D020127:Recovery of Function; D012189:Retrospective Studies; D013318:Stroke Volume; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left
keywords: 17; 20; EF; Ea; Ea/Ees; Ees; LV; LVEDV; LVEDVI; LVESV; LVESVI; PDA; POD; SD; SW/PVA; effective arterial elastance; ejection fraction; end-systolic elastance; left ventricular; left ventricular end-diastolic volume; left ventricular end-diastolic volume index; left ventricular end-systolic volume; left ventricular end-systolic volume index; patent ductus arteriosus; postoperative day; ratio of stroke work and pressure-volume area; standard deviation; ventriculoarterial coupling