ORIGINAL ARTICLE
Circulation Journal Official Journal of the Japanese Circulation Society http://www. j-circ.or.jp
Cardiovascular Surgery
Late-Onset Right Ventricular Failure in Patients With Preoperative Small Left Ventricle After Implantation of Continuous Flow Left Ventricular Assist Device Teruhiko Imamura, MD; Koichiro Kinugawa, MD, PhD; Naoko Kato, PhD; Hironori Muraoka, MD; Takeo Fujino, MD, PhD; Toshiro Inaba, MD; Hisataka Maki, MD, PhD; Osamu Kinoshita, MD, PhD; Masaru Hatano, MD; Shunei Kyo, MD, PhD; Minoru Ono, MD, PhD
Background: The continuous flow (CF) left ventricular assist device (LVAD) has replaced the pulsatile flow (PF) LVAD because of its advantages of better patient survival and higher quality of life. However, “late-onset right ventricular failure (RVF)” after CF LVAD implantation has emerged as an increasing concern, but little is known about the mechanism. Methods and Results: We retrospectively analyzed the 3-month hemodynamic and echocardiographic data from 38 consecutive patients who had received CF LVADs, and from 22 patients who had received PF LVADs. Late-onset RVF was defined as persistent right ventricular stroke work index (RVSWI) 48 h, or mechanical support for RV including extracorporeal membrane oxygenation or RV assist device (RVAD)].2,5,8,10–14,18 On the basis of this definition, many investigators including us have proposed preoperative risk factors for RVF [eg, lower RV stroke work index (RVSWI) or higher ratio of central venous pressure to pulmonary capillary wedge pressure (CVP/PCWP)].5,14,18 Most of these parameters are believed to represent preoperative latent RVF, which become clinically evident soon after the im-
Received September 26, 2013; revised manuscript received November 19, 2013; accepted November 25, 2013; released online January 16, 2014 Time for primary review: 19 days Department of Cardiovascular Medicine (T. Imamura, H. Muraoka, T.F., T. Inaba, H. Maki, M.H.), Department of Therapeutic Strategy for Heart Failure (K.K., N.K., S.K.), and Department of Thoracic Surgery (O.K., M.O.), Graduate School of Medicine, University of Tokyo, Tokyo, Japan Mailing address: Koichiro Kinugawa, MD, PhD, Department of Therapeutic Strategy for Heart Failure, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. E-mail:
[email protected] ISSN-1346-9843 doi: 10.1253/circj.CJ-13-1201 All rights are reserved to the Japanese Circulation Society. For permissions, please e-mail:
[email protected] Circulation Journal Vol.78, March 2014
626
IMAMURA T et al.
Table 1. Comparison of Early and Late-Onset RVF After LVAD Implantation Definition
Timing
Early RVF
Late-onset RVF
i.v. inotropes for >2 weeks
Persistent RVSWI 48 h
at any rotation speed or saline infusion
or mechanical RV support
(as defined in present study)
Apparent at the withdrawal of cardiopulmonary bypass
Develops over several weeks after LVAD implantation
Device type
PF and CF
Maybe only CF
Prognosis
Poor but some patients recover
Yet to be determined
Treatment
i.v. inotrope, NO, RVAD
Tricuspid valve plasty (?)
RVSWI, CVP/PCWP
Maybe small LVDd (as described in present study)
Preoperative predictors
*RVSWI = [stroke volume index (ml/m2)] × {[mean pulmonary artery pressure (mmHg)] − [mean right atrial pressure (mmHg)]} ×0.0136. CF, continuous flow; CVP, central venous pressure; i.v., intravenous; NO, nitric oxide; PCWP, pulmonary capillary wedge pressure; PF, pulsatile flow; RVAD, right ventricular assist device; RVF, right ventricular failure; RVSWI, right ventricular stroke work index.
plantation of LVAD. We call that type of RVF as “early RVF” (Table 1). Recently, several investigators, including us, have reported late-onset and progressive RVF after CF LVAD implantation in spite of lacking preoperative risk factors for the above-described postoperative “early RVF.”13,19 “Late-onset RVF” does not follow the conventional definition of early RVF but emerges several weeks after LVAD implantation.13,19 A large part of early RVF eventually resolves in a few weeks to a month even though intensive care is sometimes necessary, but late-onset RVF is often refractory to medical therapy or adjustment of rotation speed. Late-onset RVF is persistent and therefore a great concern, especially in Japan, because of the long waiting periods on VAD resulting from the extreme shortage of donor hearts.20 However, the mechanism of late-onset RVF remains to be elucidated. Therefore, we define it here as persistent RVSWI 2 weeks and/or inhalation of nitric monoxide for >48 h, or mechanical support for RV including extracorporeal membrane oxygenation or RVAD, were excluded from this study. Intra-aortic balloon pumping (IABP) was executed if necessary on the basis of the physicians’ decision prior to LVAD insertion. Concomitant tricuspid annuloplasty (TAP) was performed when preoperative tricuspid regurgitation (TR) was graded as moderate to severe. All patients were listed for heart transplantation before LVAD implantation. Written informed consent was given before LVAD implantation by the patients and/or their family members in all cases. The study protocol was approved by the Ethics Committee of the Graduate School of Medicine, the University of Tokyo [application number 779 (1)]. Variables Evaluated In the CF LVAD group, baseline clinical data including each
patient’s demographics, and the laboratory, hemodynamic, and echocardiographic data obtained within 15 mmHg. Hemodynamic parameters were monitored through the central vein during the 15-min saline infusion. “Suck down” phenomenon was carefully surveyed by monitoring the size of the LV cavity, the distance between the LV wall and LVAD inflow cannula, sudden decrease in cardiac output, and ventricular ectopy. Laboratory and echocardiographic data were obtained and the 6-min walking distance was measured together with cardiopulmonary exercise testing in all the CF LVAD patients at 3 months after the operation. In the PF LVAD group, the hemodynamic study and echocardiography were executed before (2.0 mg/dl, and serum creatinine >2.3 mg/dl, to predict early RVF after LVAD implantation. The TRV score consisted of CVP/PCWP >0.5, body surface area 1,200 pg/ml, and left ventricular diastolic diameter (LVDd) 20 points had a higher probability of requiring perioperative mechanical RV support with severe early RVF. The TVAD score consisting of serum albumin 4.8 mg/dl, CVP >11 mmHg, and LVDd
