HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Fernández, A. L. Articles by Martínez, A. Search for Related Content PubMed PubMed Citation Articles by Fernández, A. L. Articles by Martínez, A. Related Collections Mechanical Circulatory Assistance Related Article

Ann Thorac Surg 2002;73:1689
© 2002 The Society of Thoracic Surgeons

---

Correspondence

Monitoring recovery and weaning from the thoratec left ventricular assist device

^a Departments of Cardiac Surgery and Cardiology Hospital Clínico Universitario de Santiago Ave. Choupana, s/n 15706 Santiago de Compostela, Spain

e-mail: alfg{at}inicia.es

To the Editor

We read with interest the article by Slaughter and colleagues [1]. This excellent article describes a new technique for monitoring myocardial recovery and a weaning protocol, which permits gradual ventricular reloading and a longer period of observation before device removal.

Several questions remain related to the experience reported by Slaughter and associates.

First, what were the criteria for patient selection? Data dealing with preoperative left ventricular function and size and peak oxygen consumption as well as pulmonary artery pressure and resistance are not shown. All the patients underwent mitral valve reconstruction with an annuloplasty ring. The main purpose of the procedure was to reduce mitral regurgitation. We assume that a left ventricular assistance device was inserted because intraaortic balloon counterpulsation failed to wean the patients from cardiopulmonary bypass.

Second, what was the postoperative course during the supported period? The functional class of the patients during recovery is not shown. On the other hand, the duration of support is highly variable (between 30 and 181 days). When did myocardial function normalize and how many times was weaning interrupted?

Third, what are the possible advantages of your weaning method? During weaning, console pumping was changed to an asynchronous fixed rate. Using this mode of pumping ejection is independent of the cardiac cycle. At times the device is synchronous; at other times it is counterpulsing. Increasing device rate and duration of systole reduces device filling and stroke volume. Reduced device stroke volume irreqularly loads the native heart that is ejecting independently.

We previously reported a case of successful weaning from a Thoratec left ventricular assist device using a synchronous conterpulsating mode and increasing the pumping interval from 1:1 to 1:2 and 1:3 [2]. Although superiority of synchronous over asynchronous pumping has not been observed [3], asynchronous counterpusaltion may provide maximal diastolic augmentation to increase subendocardial perfusion and improve heart recovery [4].

Fourth, all 6 patients were weaned from the left ventricular assist device and discharged home. Ventricular performance and functional status were improved at 6 months of follow-up. The authors concluded that patients with advanced heart failure and severe mitral insufficiency can benefit from mechanical unloading. Nevertheless, the observed intermediate-term myocardial recovery may also be explained by reduced mitral regurgitation. Medium-term improvement in cardiac output, ventricular volume and performance, and functional class is also observed in patients with dilated cardiomyopathy and severe mitral regurgitation who had mitral valve repair without mechanical ventricular unloading [5].

References

1. Slaughter M.S., Silver M.A., Farrar D.J., Tatooles A.J., Pappas P.S. A new method of monitoring recovery and weaning the Thoratec left ventricular assist device. Ann Thorac Surg 2001;71:215-218.[Abstract/Free Full Text]
2. Fernández A., Herreros J.M., Llorens R., Martínez A., Panizo A., Manito N. Primary graft failure after heart transplantation. Successful recovery with pneumatic biventricular assistance. Int J Artif Organs 1996;19:307-310.[Medline]
3. Cohen D.J., Clen M.F., Luther M., et al. Effect of synchronous and asynchronous pulsatile flow during left, right and biventricular bypass. Artif Organs 1992;16:614-622.[Medline]
4. Gutfinger D.E., Ott R.A., Eugene J., Gazzaniga A.B. Concepts in the application of pneumatic ventricular assist devices for ischemic myocardial injury. ASAIO J 1995;41:162-168.[Medline]
5. Bolling S.F., Pagani F.D., Deeb G.M., Bach D.S. Intermediate term outcome of mitral reconstruction in cardiomyopathy. J Thorac Cardiovasc Surg 1998;115:381-386.[Abstract/Free Full Text]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Fernández, A. L. Articles by Martínez, A. Search for Related Content PubMed PubMed Citation Articles by Fernández, A. L. Articles by Martínez, A. Related Collections Mechanical Circulatory Assistance Related Article