Ann Thorac Surg 1996;61:1314-1315
© 1996 The Society of Thoracic Surgeons
Invited Commentary
Invited Commentary
Davis C. Drinkwater, Jr, MD
Cardiothoracic Surgery, UCLA Medical Center, 10833 Le Conte Ave, Los Angeles, CA 90095-1741
See also page 1310.
This study by Carrier and co-authors raises issues important to cardiac transplantation in 1996. Namely, what are the factors that cause a single center's mortality from early graft failure to more than double as it did in their experience during the study period (from 4% to 8.8%)? There has been a general trend in many transplant programs to accept less optimal donors, primarily due to the growing discrepancy between the numbers of recipients and donors, and it would appear that Carrier and co-authors' program is no exception. Although it can not be assumed, it is likely, based on the information provided in this report, that recipients from both eras in this study are roughly comparable, and therefore patient characteristics are not a major factor in outcomes resulting in a ventricular assist device incidence of 6% for the retrograde and 12% for the nonretrograde groups, respectively. Further, a mortality rate of 17.6% in the nonretrograde group is far in excess of that reported by many groups using similar myocardial preservation techniques of crystalloid arrest and storage and unmodified reperfusion, particularly with the reported short ischemic times averaging slightly more than 2 hours (130 minutes). These figures are in sharp contrast to the 4% mortality rate reported by Carrier and co-authors in their earlier experience from 1983 to 1992.
On closer inspection of the data, it is notable that despite randomization there is a trend toward a greater number of donors with cerebral hemorrhage in the nonretrograde group (60% versus 35%), accounting for 3 of the 4 failed hearts. It is increasingly recognized that organs from donors with cerebral hemorrhage are at greater risk for early graft failure due to a number of effects of chronic hypertension and a strong association with female donors. Additionally, 3 donors from the nonretrograde group had significant wall motion abnormalities (1 by angiogram and 2 by echocardiogram), again very clearly associated with less optimal early outcomes. Carrier and co-authors' claim of possible benefits from retrograde warm blood cardioplegia is supported by trends only in both outcome and metabolic data that appear strongly confounded by a less ideal donor population. This is particularly so if one excludes the retransplanted heart as the fourth primary graft failure; the risk of early failure in even optimal hearts is much greater in the situation of retransplantation within 48 hours, due to the interaction of many host factors on the newly implanted heart. In this particular graft, postoperative evidence of a frank inferior wall myocardial infarction points less to inadequate preservation techniques and more to an intrinsic graft issue of either underlying atherosclerosis or a technical problem such as air or particulate embolus. It may well be that a larger multicenter trial might convert the trends found in this smaller study to significant differences to allow us to make strong inferences about the specific techniques involved.
This study is, in effect, a comparison of some modified reperfusion with retrograde warm blood cardioplegia versus none (nonretrograde), and the results are unlikely to be due to the particular attributes of the method of administration itself. In fact, during the study period, Carrier and co-authors made modifications in their retrograde techniques, having recognized and attempted to address inherent problems with warm retrograde protection and the right ventricle in particular, which is generally the most vulnerable for acute failure early after transplantation. If prolonged ischemic times were an issue, one could just as easily institute early antegrade reperfusion before both pulmonary artery and atrial or caval anastomoses. One would need to perform a comparison trial between antegrade- and retrograde-administered modified reperfusate to draw any valid conclusions on one technique versus another. This study is valuable in demonstrating that as more marginal donors are considered and used, improvements in myocardial preservation and reperfusion techniques are required to achieve favorable (even comparable) outcomes. With respect to cardiac transplantation, it is likely that the methods of administration will be interchangeable and play a secondary role to the solutions themselves.
Related Article
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Clinical Trial of Retrograde Warm Blood Reperfusion Versus Standard Cold Topical Irrigation of Transplanted Hearts
- Michel Carrier, Tack Ki Leung, B. Charles Solymoss, Raymond Cartier, Yves Leclerc, and L. Conrad Pelletier
Ann. Thorac. Surg. 1996 61: 1310-1314.
[Abstract]
[Full Text]
