Folland E D, Vogel R A, Hartigan P, Bates E R, Beauman G J, Fortin T, Boucher C, Parisi A F
Research Service, Veterans Affairs Medical Centers, West Roxbury, Mass.
Circulation. 1994 May;89(5):2005-14. doi: 10.1161/01.cir.89.5.2005.
Practitioners often assume a close relation between angiographic coronary artery stenosis and patient functional capacity. To test this unproven hypothesis, we analyzed the relation between coronary artery stenosis measured by different methods and maximal treadmill exercise tolerance in patients with single-vessel disease before and after intervention by percutaneous transluminal coronary angioplasty (PTCA).
Coronary angiography and maximal exercise testing off anti-ischemic medication were performed before random assignment of 227 patients with single-vessel coronary artery disease to PTCA or drug therapy. Six months later, angiography and exercise testing were repeated with patients assigned to PTCA off anti-ischemic therapy so that the altered coronary stenosis was the only consistent variable. Patients assigned to drug therapy were exercised on drug therapy. Coronary stenosis was assessed visually by the local investigator and quantitatively by blinded caliper and computer methods in central laboratories. Variabilities of caliper and computer measurements were established in a subset read twice. Visually estimated stenosis > or = 90% at baseline was associated with shorter exercise duration (7.9 versus 9.2 minutes, P < .04). Similar segregation at baseline was not observed with caliper or computer methods. Regardless of the method of measurement used, correlation between changes of lesion severity and exercise duration from baseline to follow-up was poor. Patients were angiographically classified as "better," "unchanged," or "worse" if follow-up stenosis was below, within, or above 2 SD of mean technical variability from baseline (+/- 18.8%, caliper, +/- 14.6%, computer). Exercise duration for PTCA patients improved among those with better lesions (+2.4 minutes, n = 50, P = .001) but also among those with unchanged lesions (+1.9 minutes, n = 41, P < or = .001). Unchanged medically treated patients improved less (+0.5 minutes, n = 86, P = .04). Results were similar when patients were angiographically classified by minimum lumen diameter.
Handheld calipers and quantitative coronary angiography are equivalent techniques for making anatomic measurements. Neither method identified patients having reduced exercise capacity at baseline as well as visual estimation. The relation between changes of coronary stenosis and exercise duration is highly variable, at least in part because of the insensitivity of angiographic methods for detecting small but potentially important changes. Minimal anatomic improvement 6 months after PTCA does not preclude a good functional outcome. Contrary to common belief, angiographic stenosis does not correlate well with functional capacity, even in patients with single-vessel disease.
从业者通常假定冠状动脉造影狭窄与患者的功能能力之间存在密切关系。为了验证这一未经证实的假设，我们分析了在经皮腔内冠状动脉成形术（PTCA）干预前后，单支血管病变患者中，不同方法测量的冠状动脉狭窄与最大运动耐量之间的关系。
在将227名单支血管冠状动脉疾病患者随机分配接受PTCA或药物治疗之前，进行了冠状动脉造影和停用抗缺血药物后的最大运动测试。六个月后，对接受PTCA且停用抗缺血治疗的患者重复进行造影和运动测试，以使改变的冠状动脉狭窄成为唯一的一致变量。分配接受药物治疗的患者在药物治疗期间进行运动测试。冠状动脉狭窄由当地研究人员进行视觉评估，并由中心实验室的盲法卡尺和计算机方法进行定量评估。在一个子集样本中进行两次读取，确定卡尺和计算机测量的变异性。基线时视觉估计狭窄≥90%与运动持续时间较短相关（7.9分钟对9.2分钟，P<.04）。使用卡尺或计算机方法在基线时未观察到类似的分类情况。无论使用何种测量方法，从基线到随访期间病变严重程度的变化与运动持续时间之间的相关性都很差。如果随访狭窄低于、在或高于基线平均技术变异性的2个标准差（卡尺为±18.8%，计算机为±14.6%），则患者在造影上被分类为“改善”、“不变”或“恶化”。PTCA患者中，病变改善的患者运动持续时间有所改善（增加2.4分钟，n = 50，P =.001），病变不变的患者运动持续时间也有所改善（增加1.9分钟，n = 41，P≤.001）。药物治疗不变的患者改善较少（增加0.5分钟，n = 86，P =.04）。当根据最小管腔直径对患者进行造影分类时，结果相似。
手持卡尺和定量冠状动脉造影是进行解剖测量的等效技术。两种方法在识别基线时运动能力降低的患者方面都不如视觉评估。冠状动脉狭窄变化与运动持续时间之间的关系高度可变，至少部分原因是造影方法检测微小但可能重要变化的不敏感性。PTCA术后6个月最小的解剖学改善并不排除良好的功能结果。与普遍看法相反，即使在单支血管病变患者中，造影狭窄与功能能力也没有很好的相关性。
