Stroke occurred more often postoperatively than intraoperatively in more than 45,000 patients who underwent coronary artery bypass grafting at a single center during a 30-year period, according to a report in the Jan. 26 issue of JAMA.
The overall incidence of CABG-related stroke also declined since the late 1980s, even though the risk profiles of patients have been worsening at the same time, with the procedure being performed in recent years in more patients who have hypertension, diabetes, and even a history of stroke, Dr. Khaldoun G. Tarakji and his associates at the Cleveland Clinic reported (JAMA 2011:305:381-90).
They studied the timing of CABG-related stroke because few studies have examined the issue and because “understanding the risk factors specific to the timing ... should be beneficial in identifying the cause of the stroke and developing preoperative, operative, and postoperative strategies to predict and prevent stroke.”
Dr. Tarakji and his colleagues reviewed 45,432 consecutive cases of CABG at their center during 1982-2010. Overall, 1.6% of patients developed perioperative stroke.
After peaking at 2.6% in 1988, perioperative stroke declined thereafter by 4.7% per year. “This is most likely the result of improving preoperative assessment, intraoperative anesthetic and surgical techniques, and postoperative care,” they noted.
Approximately three-fifths of the patients who developed stroke did so postoperatively, with the incidence peaking at day 2 and reverting to a constant hazard of 0.05% by day 6.
“The inflammatory process and hypercoagulability after surgery might provide some explanation for this peak. Identifying the etiology of this postoperative risk factor for stroke may lead to better strategies to prevent it, whether through more aggressive use of antithrombotic and antiplatelet agents, prophylactic prevention of atrial fibrillation, or both,” the investigators wrote.
Surprisingly, new-onset postoperative atrial fibrillation did not raise the risk of postoperative stroke.
“To treat new-onset atrial fibrillation, we initially try early medical conversion or electroconversion and, if AF recurs or is persistent, rate control and anticoagulation. This strategy appears to be associated with not only preventing an anticipated increased risk of postoperative stroke but perhaps [also] with actually lowering the risk,” they noted.
Different surgical techniques carried different risks for intraoperative stroke. “We found off-pump CABG and on-pump beating-heart CABG to be associated with the lowest risk of intraoperative stroke [0.14% and 0%, respectively], on-pump arrested-heart CABG with slightly higher risk [0.50%], and on-pump CABG with hypothermic systemic circulatory arrest with the greatest risk [5.3%],” Dr. Tarakji and his associates wrote.
“Both off-pump CABG and on-pump beating-heart CABG can be performed with minimal aortic manipulation, and therefore they likely lower the risk of stroke by decreasing the risk of aortic atherosclerotic embolization.” However, this potential benefit “must be weighed against the greater risk of incomplete revascularization, lower graft patency, and worse 1-year outcomes reported for patients undergoing off-pump CABG.”
Intraoperative stroke risk increased with advancing age when surgeons used on-pump arrested-heart CABG or on-pump CABG with hypothermic circulatory arrest, but not when they used off-pump CABG or on-pump beating-heart CABG.
“In patients at high risk of intraoperative stroke, such as the elderly or those with aortic arteriosclerosis, off-pump CABG or on-pump beating-heart CABG with no or minimal aortic manipulation may be best. However, in patients at low risk of stroke, such as those without aortic arteriosclerosis and minimal arteriosclerotic burden, on-pump CABG is likely the best option to provide optimal surgical revascularization and minimal risk of stroke,” they wrote.
The investigators cautioned that their data were drawn from a single academic medical center and thus may not be generalizable to all U.S. practice.
The study was funded by the Cleveland Clinic. One of Dr. Tarakji’s coauthors reported receiving honoraria from Medtronic.
Copyright (c) 2010 Elsevier Global Medical News. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
根据1月26日刊JAMA杂志上发表的一项研究报告，30年间在单中心接受冠状动脉旁路移植术(CABG)的45,000余例患者中，卒中更多发生于术后而不是手术期间。
克利夫兰医院的Khaldoun G. Tarakji医生及其合作者说，尽管近年来接受CABG的患者危险程度增高，更多身患高血压、糖尿病甚至有卒中病史的患者接受了CABG，但自20世纪80年代末开始，CABG相关卒中总发生率降低。之前很少有研究讨论CABG相关卒中的高发时间问题，而更好地理解与时间相关的危险因素将有助于确定卒中病因，并可据此制定术前、术中和术后治疗策略，更有效地预防CABG相关卒中。
Khaldoun G. Tarakji医生及其合作者回顾了该中心在1982~2010年间进行的连续45,432例CABG，共有1.6%的患者发生围手术期卒中。CABG围手术期卒中的发生率在1988年达到2.6%的高峰，之后以每年4.7%的比例下降，原因可能为术前评估、术中麻醉、手术技术和术后护理得到改进。发生卒中的患者中，3/5发生于术后，高峰在手术第2天，以后发生率逐渐下降，第6天以后稳定在0.05%上下。令研究者感到意外的是，术后新发心房颤动并不增加术后卒中风险。不同手术技术导致不同的术中卒中风险：不停跳CABG和体外循环下心脏不停跳CABG与术中卒中风险最低相关（分别为0.14%和0%），体外循环下心脏停跳CABG的风险略高(0.50%)，体外循环下低温停体循环CABG风险最高(5.3%)。当使用体外循环下停跳CABG或体外循环下低温停循环CABG时，术中卒中风险随年龄增大而升高，但使用不停跳CABG或体外循环下心脏不停跳CABG时，未发现这一现象。
研究者表示，确定术后危险因素的病因学有利于制定预防策略，如更积极使用抗血栓和抗血小板药物、预防心房颤动或二者同时进行。对于术中发生卒中风险较高的患者，如老年人或主动脉粥样硬化患者，无主动脉操作或主动脉操作较少的不停跳CABG或体外循环下心脏不停跳CABG是最好的。但对于卒中风险较低的患者，如无主动脉粥样硬化或动脉粥样硬化负荷较小的患者，体外循环下CABG可提供最佳外科血运重建且卒中风险最低，是最好的选择。
该研究由克利夫兰医院提供资金赞助。Tarakji医生的一位合著者披露曾接受美敦力公司的酬金。
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