Patel S T, Haser P B, Korn P, Bush H L, Deitch J S, Kent K C
Division of Vascular Surgery, New York Presbyterian Hospital, Weill Medical College of Cornell University, New York 10021, USA.
J Vasc Surg. 1999 Dec;30(6):1024-33. doi: 10.1016/s0741-5214(99)70040-6.
Recently published data from the North American Carotid Endarterectomy Trial revealed a benefit for carotid endarterectomy (CEA) in symptomatic patients with moderate (50% to 69%) carotid stenosis. This benefit was significant but small (absolute stroke risk reduction at 5 years, 6.5%; 22.2% vs 15.7%), and thus, the authors of this study were tentative in the recommendation of operation for these patients. To better elucidate whether CEA in symptomatic patients with moderate carotid stenosis is a proper allocation of societal resources, we examined the cost-effectiveness of this intervention.
A decision-analytic Markov process model was constructed to determine the cost-effectiveness of CEA versus medical treatment for a hypothetical cohort of 66-year-old patients with moderate carotid stenosis. This model allowed the comparison of not only the immediate hospitalization but also the lifetime costs and benefits of these two strategies. Our measure of outcome was the cost-effectiveness ratio (CER), defined as the incremental lifetime cost per quality-adjusted life year saved. We assumed an operative stroke and death rate of 6.6% and a declining risk of ipsilateral stroke after the ischemic event with medical treatment (first year, 9.3%; second year, 4%; subsequent years, 3%). The hospitalization cost of CEA ($6,420) and the annual costs of major stroke ($26,880), minor stroke ($798), and aspirin therapy ($63) were estimated from a hospital cost accounting system and the literature.
CEA for moderate carotid stenosis increased the survival rate by 0.13 quality-adjusted life years as compared with medical treatment at an additional lifetime cost of $580. Thus, CEA was cost-effective with a CER of $4,462. Society is usually willing to pay for interventions with CERs of less than $60,000 (eg, CERs for coronary artery bypass grafting at $9,100 and for dialysis at $53,000). CEA was not cost-effective if the perioperative risk was greater than 11.3%, if the ipsilateral stroke rate associated with medical treatment at 1 year was reduced to 4.3%, if the age of the patient exceeded 83 years, or if the cost of CEA exceeded $13,200.
CEA in patients with symptomatic moderate carotid stenosis of 50% to 69% is cost-effective. Perioperative risk of stroke or death, medical and surgical stroke risk, cost of CEA, and age are important determinants of the cost-effectiveness of this intervention.
北美颈动脉内膜切除术试验最近公布的数据显示，对于有症状的中度（50%至69%）颈动脉狭窄患者，颈动脉内膜切除术（CEA）有益。这种益处虽显著但较小（5年时绝对卒中风险降低6.5%；22.2%对15.7%），因此，本研究的作者在建议对这些患者进行手术时持谨慎态度。为了更好地阐明对有症状的中度颈动脉狭窄患者实施CEA是否合理分配社会资源，我们研究了这种干预措施的成本效益。
构建了一个决策分析马尔可夫过程模型，以确定CEA与药物治疗相比对于一组假设的66岁中度颈动脉狭窄患者的成本效益。该模型不仅可以比较即时住院情况，还可以比较这两种策略的终身成本和效益。我们的结果衡量指标是成本效益比（CER），定义为每挽救一个质量调整生命年的增量终身成本。我们假设手术卒中及死亡率为6.6%，药物治疗后缺血事件同侧卒中风险呈下降趋势（第一年9.3%；第二年4%；后续年份3%）。CEA的住院成本（6420美元）以及重大卒中的年度成本（26880美元）、轻度卒中的年度成本（798美元）和阿司匹林治疗的年度成本（63美元）是根据医院成本核算系统和文献估算得出的。
与药物治疗相比，中度颈动脉狭窄的CEA使生存率提高了0.13个质量调整生命年，终身成本增加了580美元。因此，CEA具有成本效益，CER为4462美元。社会通常愿意为CER低于60000美元的干预措施付费（例如，冠状动脉搭桥术的CER为9100美元，透析的CER为53000美元）。如果围手术期风险大于11.3%、1年时与药物治疗相关的同侧卒中率降至4.3%、患者年龄超过83岁或CEA成本超过13200美元，CEA则不具有成本效益。
对有症状的50%至69%中度颈动脉狭窄患者实施CEA具有成本效益。围手术期卒中或死亡风险、药物和手术卒中风险、CEA成本以及年龄是这种干预措施成本效益的重要决定因素。
