| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Ann Thorac Surg 2004;77:1630-1634
© 2004 The Society of Thoracic Surgeons
a Department of Cardiothoracic Surgery, University of Tokyo, Tokyo, Japan
b School Education Center, University of Tsukuba, Tokyo, Japan
c Department of Public Health, University of Tokyo, Tokyo, Japan
Accepted for publication October 2, 2003.
* Address reprint requests to Dr Miyairi, Department of Cardiovascular Surgery, Mitsui Memorial Hospital, 1 Kandaizumicho Chiyodaku, Tokyo 101-8643, Japan
e-mail: tmiyairi-tky{at}umin.ac.jp
 |
Abstract |
|---|
 Top Abstract IntroductionMaterial and methodsResultsCommentReferences |
|---|
METHODS: Forty-two patients undergoing thoracic aortic surgery using RCP were enrolled in the study. The patients' neurocognitive state was assessed by the revised Wechsler Adult Intelligence Scale (WAIS-R) a few days before operation, at 2 to 3 weeks, and at 4 to 6 months after operation.
RESULTS: There were no stroke, seizure, and hospital death. Significant performance deterioration was observed in digit span, arithmetic, and picture completion of the WAIS-R subtests. Bivariate comparison showed that older age (late vocabulary, late similarities, and late object assembly), longer RCP time (early picture arrangement, and early block design), later awake time (early and late picture arrangement, and early block design), longer respirator use (early and late digit span, late picture arrangement), longer ICU time (late picture completion, early and late picture arrangement, and early block design), and longer hospital stay (early picture arrangement) were significantly associated with the decline in neurocognitive performance. Stepwise logistic regression analysis disclosed that older age (late similarities and late object assembly), later awake time (late picture arrangement), and longer respirator use (early and late digit span, and late picture arrangement) were most predictive for the decline in neurocognitive performance.
CONCLUSIONS: On average, digit span, arithmetic, and picture completion tests were most sensitive in detecting the decline in neurocognitive performance. The relationship between the duration of RCP and neurocognitive test results was not significant.
|
Introduction |
|---|
|
TopAbstractIntroductionMaterial and methodsResultsCommentReferences |
|---|
|
Material and methods |
|---|
|
TopAbstractIntroductionMaterial and methodsResultsCommentReferences |
|---|
Methods
Anesthesia was induced intravenously with fentanyl (5 µg/kg) and midazolam (0.1 mg/kg). Tracheal intubation was performed after pancronium (0.1 mg/kg). Anesthesia was maintained by a low dose (0.5% to 1%) of sevoflurane, and additional doses of fentanyl (5 µg/kg) were given.
Surgical technique
The heart, ascending aorta, aortic arch, and arch vessels were exposed through a median sternotomy and left supraclavicular incision. After systemic heparinization, extracorporeal circulation was established with an arterial cannula placed either in the ascending aorta or the femoral artery, and bicaval cannulas through the right atrium for venous return. The left side of the heart was vented through the right superior pulmonary vein.
Core cooling was continued until a rectal temperature or a tympanic temperature of 18°C or less was obtained. The minimum period time required for cooling was 30 minutes. The juglar bulb oxyhemoglobin saturation was not monitored and near-infrared brain spectroscopy was not performed. The patients' heads were packed in ice. The systemic circulation either from the ascending aorta or the femoral artery was arrested and the ascending aorta or the aortic arch was incised. Myocardial protection was provided with antegrade blood cardioplegia perfused through a balloon catheter placed in the ascending aorta.
After a brief period of circulatory arrest, the cardiopulmonary bypass (CPB) circuit was opened and cold oxygenated blood was perfused through the superior vena caval cannula, at a rate of 300 to 500 mL/min, to keep the central venous pressure between 15 and 25 mm Hg. The arterial and inferior vena caval cannulas were clamped during the RCP period.
The descending aorta was transected either just below the origin of the left subclavian artery or distal to the descending aortic aneurysm. Obliteration of the distal false lumen in the descending aorta was performed if necessary. The distal part of the four-limbed vascular graft was anastomosed to the descending aorta. Then the left subclavian and the left common carotid arteries were sutured to each limb of the graft in succession. After the proximal graft was cross-clamped, retrograde cerebral perfusion was interrupted and antegrade systemic perfusion with rewarming through the fourth limb attached to the graft was instituted. Then, the brachiocephalic artery was anastomosed to the last limb. After the proximal graft was anastomosed to the ascending aorta, the aorta and the vascular graft were carefully filled with blood and coronary circulation was restarted. The fourth limb that was used for antegrade systemic perfusion was resected after termination of extracorporeal circulation. Cardiotomy suction was used during operation. Autotransfusion was not performed after operation.
Clinical and neurocognitive assessments
Each patient's neurologic and neuropsychological state was assessed a few days before the operation, 2 to 3 weeks after the operation, and 4 to 6 months after the operation. A well-trained psychologist, masked to the surgical treatment, performed the neurocognitive tests in a standardized manner. We subjected the patients to a battery of core tests that covered memory, language, psychomotor speed, attention, and concentration. This consisted of 11 neuropsychological tests taken from the revised Wechsler Adult Intelligence Scale (WAIS-R), which are accepted tests of global cognitive function. The tests were presented in a fixed order according to conventional practice, and the scores were arranged such that larger scores indicated better neuropsychological performance.
The protocol of this study was approved by the Research Committee, University of Tokyo. Each patient consented to an 11-part psychological examination.
Statistical analysis
Basic characteristics of study subjects, demographic and perioperative factors, which could reportedly affect neurocognitive performance, were first examined, along with the results of WAIS-R test scores. Based on the means and standard deviations of the test scores obtained preoperatively for each group, Z-scores were calculated, and the difference in test scores both between preoperative test and early postoperative test, and between preoperative and late postoperative tests were obtained. Then, the significance of these difference were tested by Wilcoxon matched-paired signed rank tests. To examine the factors that can contribute to the decline in neuropsychological performance, association of the occurrence of performance decline with possible risk factors (listed in Table 1)
were first examined bivariately by 
2 (and Fisher's exact) tests for categorical variables, and by Wilcoxon rank sum tests for continuous variables. Performance decline in early postoperative tests was defined as the decrease in test scores (Z-scores) more than one standard deviation, while that for late postoperative results is defined as any decrease in test scores, as was discussed in the previous study [3]. Significance levels were adjusted for multiple comparison by Bonferroni's method. Finally to find out the set of variables which could best predict the decline in neuropsychological performance, logistic regression analysis was conducted. All the possible risk factors were entered and removed in a stepwise fashion at the significance level of 0.05. All the statistical analysis was done using STATA version 8.1 (Stata Corporation, College Station, TX).
|
|
Results |
|---|
|
TopAbstractIntroductionMaterial and methodsResultsCommentReferences |
|---|
Concomitant operative procedures, other than the repair of the aortic arch, included coronary artery bypass grafting in 7 patients, aortic root replacement in 2, aortic valve replacement in 2, mitral valve replacement in 1, repair of aortic dissection in 6, stent-graft insertion in 2, redo aortic surgery in 3, and minimally invasive approach in 1 patient.
There was no hospital mortality in the group. None suffered a stroke or seizure, including by electro-encephalogram.
Postoperative major complications other than neurologic disorders included postoperative bleeding in 1 patient, low cardiac output in 1, respiratory failure in 3, acute renal failure in 1, gastrointestinal bleeding in 1, and temporary hoarseness in 2 of the patients.
All of the 42 patients underwent the neurocognitive tests preoperatively and 2 to 3 weeks after operation, before discharge from the hospital. Finally, 40 patients were tested 4 to 6 months after operation at the outpatient follow-up visit.
Significant decrease (performance deterioration) was observed in digit span, arithmetic, and picture completion of the WAIS-R subtests, both between preoperative and early postoperative test results, and between base line and late postoperative test results (Table 2). Deterioration in neurocognitive performance both between before and early object assembly, and between before and late digit symbol were also significant.
|
|
|
|
Comment |
|---|
|
TopAbstractIntroductionMaterial and methodsResultsCommentReferences |
|---|
Retrograde cerebral perfusion has been advocated as an effective measure for brain protection by supplying oxygen and substrates in the retrograde manner, providing uniform brain cooling, and flushing air and material debris. Retrograde cerebral perfusion is considered to be particularly effective for reducing the risk of embolism by flushing potential embolic materials [4]. Several clinical studies demonstrated that the use of RCP had a protective effect against stroke compared with absence of RCP [5, 6]. However, recent reports indicated that RCP does not perfuse the brain homogenously [7]. Moreover, it has been reported that RCP was associated with cerebral complications when the duration of hypothermic circulatory arrest (HCA) with RCP was prolonged [8].
In the study, neurologic outcome was excellent in that there were no seizure or stroke, suggesting that RCP within the range of the current study (23 to 90; mean, 56.3 minutes.) provide acceptable levels of brain protection.
The neurocognitive state in adult patients after surgery using HCA has been discussed in several reports [3, 9–13]. Welz and colleagues [9] compared 23 patients in the late postoperative period of surgery using HCA with 10 healthy subjects. The patient group did worse than the reference group on all measures.
No previous reports have demonstrated adjunctive protective effect of RCP on neurocognitive outcome. Svensson and associates [10] assessed 30 patients undergoing either HCA alone, HCA plus RCP, or selective cerebral perfusion (SCP), along with 5 controls undergoing coronary artery bypass graft surgery, at various postoperative periods: 3 to 6 days, 2 to 3 weeks, and approximately 6 months after operation. Ninety-six percent of these patients had clinical neurocognitive impairment at 3 to 6 days, but by 2 to 3 weeks only 9% had a residual new deficit, and by 6 months these 3 patients had recovered. No neurocognitive advantage of RCP or SCP over HCA alone has been observed. Reich and associates [11] assessed 12 RCP patients and 44 HCA patients several weeks postoperatively. Relative to HCA, RCP was associated with memory dysfunction and an overall increase in neurocognitive dysfunction in multiple domains, even when controlling separately for age and cerebral ischemia time.
Although it has been demonstrated that circulatory arrest time correlated inversely with the neurocognitive scores [3, 9, 10], the current study failed to show significant association between the duration of RCP and deterioration in neurocognitive performance. It is possible that all of the patients undergoing RCP within the range of the current study had acceptable levels of neurocognitive state postoperatively. However, it is also possible that, regardless of RCP time, patients had suboptimal neurocognitive scores compared with patients undergoing HCA alone, possibly due to a detrimental effect of RCP versus HCA. The number of patients in the current study may not be large enough for multivariate logistic regression analysis. The finding of significant association between RCP time and decline in some of the early test results by bivariate comparison suggests that relationship between RCP time and neurocognitive performance may become clear when increased number of patients are included.
Because the current study does not include patients undergoing HCA alone, the additive effect of RCP over HCA alone remains uncertain. To elucidate the true effect of RCP on neurocognitive function and to decide the safety limit of RCP time, further prospective randomized investigation that include a patients group undergoing HCA alone and ideally a nonoperated control group to compensate for the practice effect on test scores, increased number of RCP patients, and desirably long-term follow-up, such as 3 to 5 years, are warranted.
Older age was predictive for the decline in some test results, as was consistent with earlier reported experiences [3, 10, 11]. The finding of performance deterioration in patients requiring prolonged ventilation was interesting. In many patients, longer ventilation time reflected later awakening and led to longer ICU stay. These factors were also associated with decline in some test results by bivariate comparison. It has been demonstrated that patients requiring longer intubaton after coronary artery bypass operation showed higher postoperative levels of serum S100b [14, 15], although no correlation were found between S100b levels and early or late neurocognitive impairment [14].
The dichotomization of neurocognitive outcome may be a confounding factor because selection of appropriate cutoff values is difficult. However, factors significantly associated with the decline in neurocognitive performance did not differ from stepwise logistic regression analysis between possible affecting factors and changes in neurocognitive scores, in which all of the outcomes are treated as continuous data (mean Z-scores).
In summary, neurologic outcome in patients undergoing RCP within the range of the current study was acceptable. Digit span, arithmetic, and picture completion tests of WAIS-R were most sensitive in detecting the decline in neurocognitive performance. Robust relationship between the duration of RCP and the decline in neurocognitive performance was not demonstrated. The uncertainty of the role of RCP versus HCA alone and SCP remains to be further examined.
|
References |
|---|
|
TopAbstractIntroductionMaterial and methodsResultsCommentReferences |
|---|
This article has been cited by other articles:
|
|
 |
|
  T. Miyairi, S. Takamoto, Y. Kotsuka, A. Takeuchi, K. Yamanaka, and H. Sato Comparison of neurocognitive results after coronary artery bypass grafting and thoracic aortic surgery using retrograde cerebral perfusion Eur. J. Cardiothorac. Surg., July 1, 2005; 28(1): 97 - 101. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
