J Thorac Cardiovasc Surg 1997;114:140-141
© 1997 Mosby, Inc.
COMBINED SUPPRESSIVE EFFECT OF CARDIOPULMONARY BYPASS AND AGING ON CELL-MEDIATED IMMUNITY
Kouichi Hisatomi, MD,
Akira Kobayashi, MD,
Yukinori Moriyama, MD,
Shinji Shimokawa, MD,
Hitoshi Toyohira, MD,
Akira Taira, MD
Kagoshima, Japan
From the Second Department of Surgery, Faculty of Medicine, Kagoshima University, Kagoshima, Japan.
Received for publication Dec. 16, 1996 accepted for publication Jan. 22, 1997.
Address for reprints: Kouichi Hisatomi, MD, Second Department of Surgery, Faculty of Medicine, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890, Japan.
The suppressive effect of cardiopulmonary bypass (CPB) on cell-mediated immunity has been investigated in patients after cardiac surgery.
1,2 Immunity also reportedly declines with aging. 3 With the recent progress in cardiac surgery, more elderly patients become surgical candidates. 4 In this article, we examined the effect of CPB on cell-mediated immunity in elderly patients compared with younger patients.
Thirty male patients underwent elective coronary artery bypass grafting under same condition (anesthesia, CPB circuit, cardioplegia, oxygenator) and were divided into two equal groups by operative age. Mean age was 56.3 years (range 41 to 66 years) in group I and 74.1 years (range 72 to 81 years) in group II. The patients did not receive steroids or homologous blood transfusions during or after the operation. Clinical data of both groups were matched according to the preoperative New York Heart Association class and CPB time. None had perioperative myocardial infarction or infection. Peripheral blood samples were taken before the operation and on postoperative days (POD) 1, 3, and 7. The natural killer (NK) cell activity was measured by cytotoxity against the 51Cr-labeled K562 cells and expressed as percent cytolysis. Cytotoxic T-cell line was used for measurement of interleukin-2 (IL-2) production. The standard level (mean ± standard deviation) of NK-cell activity (50:1) in men is 49% ± 11% and the IL-2 production range is 15 to 25 U/5 x 105 cells. Data (mean ± standard error) were analyzed by the two-way repeated-measures analysis of variance (ANOVA). Intergroup comparisons were performed with the use of the unpaired t test or the Mann-Whitney U test, as appropriate.
Preoperative and postoperative levels of NK-cell activity (percent) and IL-2 production (U/5 x 105 cells) are shown in Table I. No significant intergroup differences were observed in NK-cell activity and IL-2 production before the operation. NK-cell activity was suppressed on POD 1 and returned to the preoperative level by POD 7 in group I. In group II, this response was similar on POD 1 but more suppressed on POD 3 and POD 7. Recovery of NK-cell activity was significantly delayed in group II on POD 7 (p < 0.01; ANOVA: p [group] = 0.0251, p [time] < 0.0001, p [interaction] = 0.0033). IL-2 production showed a similar tendency, that is, deeply suppressed on POD 1 in both groups and more suppressed in group II on POD 3 and POD 7 (p < 0.01; ANOVA: p [group] = 0.0113, p [time] < 0.0001, p [interaction] < 0.0001).
The age-associated decline in immune function is difficult to assess. However, in cardiac transplantation, a postoperative decline in immune responsiveness with aging has recently been recognized; the rejection rate in elderly patients (>60 years) was significantly less than in younger patients, but elderly patients were more likely to die of postoperative infections or malignancy. 5 Preoperatively, our results did not show intergroup difference in functional status on the basis of cell-mediated immunity, but they suggest that the response to CPB was more prolonged in elderly patients.
References
-
Hisatomi K, Isomura T, Kawara T, Yamashita M, Hirano A, Yoshida H, et al. Changes in lymphocyte subsets, mitogen responsiveness, and interleukin-2 production after cardiac operations. J Thorac Cardiovasc Surg 1989;98:580-91.[Abstract]
-
Nguyen DM, Mulder DS, Shennib H. Effect of cardiopulmonary bypass on circulating lymphocyte function. Ann Thorac Surg 1992;53:611-6.[Abstract]
-
Fernandez LA, MacSween JM, Langley GR. Lymphocyte responses to PHA: age-related effects. Immunology 1976;31:583-7.[Medline]
-
Salomon NW, Page US, Bigelow JC, Krause AH, Okies JE, Metzdorff MT. Coronary artery bypass grafting in elderly patients. J Thorac Cardiovasc Surg 1991;101:209-18.[Abstract]
-
Bull DA, Karwande SV, Hawkins JA, Neumayer LA, Taylor DO, Jones KW, et al. Long-term results of cardiac transplantation in patients older than sixty years. J Thorac Cardiovasc Surg 1996;111:423-8.[Abstract/Free Full Text]
