Bry J D, Belkin M, O'Donnell T F, Mackey W C, Udelson J E, Schmid C H, Safran D G
Department of Surgery, New England Medical Center Hospitals, Boston, MA 02111.
J Vasc Surg. 1994 Jan;19(1):112-21; discussion 121-4. doi: 10.1016/s0741-5214(94)70126-1.
The approach to cardiac risk stratification of patients undergoing vascular surgery continues to be controversial. The success of algorithms that use clinical risk factors to determine cardiac risk have been inconsistent. Dipyridamole myocardial scintigraphy (DMS) has been accepted as a sensitive, noninvasive approach to risk stratification with excellent negative predictive value. Low positive predictive value (PPV) of abnormal DMS scans is a shortcoming that contributes to extensive preoperative cardiac evaluation and intervention with associated morbidity, mortality, and cost in most patients who undergo uncomplicated vascular procedures, regardless of DMS results.
Over 6 years, 237 patients underwent DMS before surgical management of infrarenal aortic aneurysm, aortoiliac, or infrainguinal occlusive disease. The value of multiple clinical factors and DMS were assessed retrospectively for the prediction of perioperative myocardial infarction (MI), heart-related death, or preoperative selection for myocardial revascularization. Only congestive heart failure and two or more reversible defects on DMS were statistically significant on logistic regression analysis.
The PPV of DMS was 19% for all patients with reversible defects, 12% for patients with one reversible defect, and 36.7% for patients with two or more reversible defects. The rates of cardiac death and MI were 1.3% and 5.9%, respectively. Perioperative echocardiography revealed unchanged postinfarction ejection fraction in most patients who experienced MI. Cost-effectiveness of DMS screening was evaluated.
The costs per MI and cardiac death averted suggest a decline in cost-effectiveness of screening with DMS over time, assuming improving cardioprotective strategies of patient care. Clinical risk factors were minimally useful in the prediction of perioperative MI, heart-related death, or need for myocardial revascularization. The PPV of DMS is low, and the majority of MIs may be clinically insignificant. The cost-effectiveness of cardiac screening with DMS may not be justifiable given current trends of health care reform.
血管手术患者的心脏风险分层方法一直存在争议。使用临床风险因素来确定心脏风险的算法成功率并不一致。双嘧达莫心肌闪烁显像（DMS）已被公认为一种敏感的、非侵入性的风险分层方法，具有出色的阴性预测价值。DMS扫描异常的阳性预测值（PPV）较低，这一缺点导致在大多数接受简单血管手术的患者中，无论DMS结果如何，都需要进行广泛的术前心脏评估和干预，从而带来相关的发病率、死亡率和成本。
在6年多的时间里，237例患者在接受肾下腹主动脉瘤、主髂动脉或股腘动脉闭塞性疾病的手术治疗前接受了DMS检查。回顾性评估多种临床因素和DMS对于围手术期心肌梗死（MI）、心脏相关死亡或心肌血运重建术前选择的预测价值。在逻辑回归分析中，只有充血性心力衰竭和DMS上两个或更多可逆性缺损具有统计学意义。
所有有可逆性缺损的患者中，DMS的PPV为19%，有一个可逆性缺损的患者为12%，有两个或更多可逆性缺损的患者为36.7%。心脏死亡和MI的发生率分别为1.3%和5.9%。围手术期超声心动图显示，大多数发生MI的患者梗死后期射血分数无变化。评估了DMS筛查的成本效益。
假设患者护理的心脏保护策略不断改进，每避免一例MI和心脏死亡的成本表明，随着时间的推移，DMS筛查的成本效益会下降。临床风险因素在预测围手术期MI、心脏相关死亡或心肌血运重建需求方面作用极小。DMS的PPV较低，而且大多数MI在临床上可能并不重要。鉴于当前医疗改革的趋势，DMS心脏筛查的成本效益可能不合理。
