冠脉旁路移植术死亡率难达≤1%目标

明尼阿波利斯——美国胸外科协会(AATS)年会上公布的一项多中心胸外科学会数据库分析显示，直接单纯冠状动脉旁路移植术(CABG)死亡率≤1%的目标只有在高度选择的患者中才能达到。在护理过程没有其他改进的情况下，仅有不到60%的CABG患者有望达到这一目标。


Damien LaPar医生

弗吉尼亚大学的Damien LaPar医生及其同事采用胸外科学会(STS)的成人心脏手术数据库，分析了2001~2011年在弗吉尼亚州17个心脏手术中心接受CABG的34,416例患者(占该州所有心脏手术的99%)的资料。研究者采用多重logistic回归模型来识别基于STS死亡风险预测(PROM)评分可达到1%死亡率目标的患者人群。

患者的平均年龄为64岁，27%为女性。手术死亡率为1.87% (644例死亡)。

校正手术年份和手术量后，在线性模型[比值比(OR) 1.89；P＜0.0001]和非线性模型(OR 6.59；P＜0.0001)中均观察到STS PROM与CABG死亡率高度相关。进一步检查发现，STS PROM评分≤1.27%与CABG死亡概率≤1%相关。然而，在估计风险＞25%的患者中，STS评分工具的预测能力下降。

研究者随后评估了风险校正的死亡率与30个用于计算STS PROM的变量和护理过程指标(如乳内动脉移植术及围手术期/出院药物)之间的关联。

在所有患者中均观察到一些护理过程、外科医生和手术因素与CABG死亡相关，但在STS PROM评分≤1.27%的风险较低的患者中观察到的关联更强。

在14,687例STS评分＞1.27%的风险较高的患者中，死亡者的中位STS评分显著高于存活者(4.6% vs. 2.4%；P＜0.001)。

CABG期间死亡的风险较高患者的年龄显著更高(72.3岁vs. 70.4岁)，并且以下比例显著更高：具有肾功能不全/透析(11.3% vs. 5.3%)、周围血管疾病(32% vs. 24%)、心力衰竭(37.3% vs. 21%)、纽约心脏协会IV级(41.6% vs. 26%)、房颤(11% vs. 7%)、 曾进行急诊手术(17% vs. 7.3；所有P＜0.001)。

风险较高的死亡者出院时接受β受体阻滞剂治疗(20% vs. 86%)、抗血小板药物(21% vs. 94.5%)和降脂药物(19.5% vs. 85%；P均＜0.001)的比例也较低。

研究者表示，STS PROM评分可用于强烈识别估计死亡风险阈值≤1.27%的、可达到1%死亡率目标的患者。

一些与会者担心患者是否持续使用阿司匹林直至手术当天或是否正在使用氨甲环酸，因为这些可影响对结果的解读。LaPar医生表示，允许使用阿司匹林至手术当天，但分析对此进行了校正，并且使用的都是ε氨基己酸(Amicar)而非氨甲环酸。

LaPar医生声明无经济利益冲突。

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By: PATRICE WENDLING, Cardiology News Digital Network

MINNEAPOLIS – Achieving a 1% or less operative mortality for primary, isolated coronary artery bypass grafting is feasible only in highly selected patients, according to a multicenter Society for Thoracic Surgery database analysis.

"This goal may only be achievable in less than 60% of CABG patients without other improvements in processes of care," said Dr. Damien LaPar, chief resident in the department of surgery, University of Virginia, Charlottesville.

The cardiothoracic surgical leadership recently threw down the gauntlet, challenging the surgical community to achieve a CABG mortality rate of 1% or less nationwide in the next 3-5 years (Ann. Thor. Surg. 2012;94:1044-52).

Operative mortality currently stands at about 2% for CABG versus about 1% for percutaneous coronary intervention (PCI). Use of CABG has fallen off as first-line treatment for coronary artery disease with advances in PCI technology.

Dr. LaPar and his associates used the Society of Thoracic Surgery (STS) database for adult cardiac surgery to analyze the records of 34,416 patients who had undergone CABG from 2001 to 2011 at 17 cardiac surgery centers in Virginia, representing 99% of all cardiac surgeries performed in the state. Multiple logistic regression modeling was used to identify patient populations in which the 1% mortality goal was achievable, relative to the STS Predicted Risk of Mortality (PROM) score.

The patients’ average age was 64 years and 27% were female. The median number of CABG operations performed over the 10-year study period was 544, with an operative mortality of 1.87% (644 deaths), Dr. LaPar reported at the annual meeting of the American Association for Thoracic Surgery.

The STS PROM was highly associated with CABG mortality in both linear (odds ratio 1.89; P less than .0001) and nonlinear (OR 6.59; P less than .0001) models, after adjustment for operative year and surgeon volume.

Upon closer inspection, an STS PROM score of 1.27% or less was found to correlate with a probability of CABG death of 1% or less, he said. The predictive ability of the STS scoring tool appeared to wane, however, for those patients with an estimated risk exceeding 25%.

The investigators then evaluated the risk-adjusted association between mortality and 30 variables used to calculate the STS PROM and process-of-care measures such as internal mammary artery grafting and perioperative/discharge medications.

Several process-of-care, surgeon, and operative factors were correlated with CABG death among all patients, although the relationship was stronger in those at lower risk with an STS PROM score of 1.27% or less, Dr. LaPar said.

Among the 14,687 higher-risk patients with an STS score exceeding 1.27%, the median STS score was significantly higher among decedents than survivors (4.6% vs. 2.4%; P less than .001).

Higher-risk patients who died during CABG were significantly more likely to be older (72.3 years vs. 70.4 years), to have renal dysfunction/dialysis (11.3% vs. 5.3%), peripheral vascular disease (32% vs. 24%), heart failure (37.3% vs. 21%), New York Heart Association class IV (41.6% vs. 26%), and atrial fibrillation (11% vs. 7%), and to have undergone emergent surgery (17% vs. 7.3; all P less than .001).

Higher-risk decedents were also less likely to be on such process measures at discharge as beta-blocker therapy (20% vs. 86%), anti-platelets (21% vs. 94.5%), and lipid-lowering medications (19.5% vs. 85%; all P less than .001), Dr. LaPar said.

"The STS Predicted Risk of Mortality score can be used to strongly identify patients with a threshold value of estimated mortality risk of less than or equal to 1.27% to achieve this [1% mortality] goal," he noted.

During a discussion of the results, some members of the audience raised concerns about whether patients continued on aspirin therapy until the day of surgery or were using tranexamic acid, as these agents could impact interpretation of the results. Dr. LaPar said that aspirin was allowed up to the day of surgery, but that the analyses corrected for this, and that all patients received epsilon-aminocaproic acid (Amicar), not tranexamic acid.

Dr. LaPar reported having no financial disclosures.