Kimball B P, Bui S, Cohen E A, Carere R G, Adelman A G
Department of Medicine, Toronto and Mount Sinai Hospital, Ontario.
Can J Cardiol. 1993 Mar;9(2):177-85.
To evaluate evolving selection criteria and angiographic outcome ('learning curve') for directional coronary atherectomy.
Tertiary referral, university-based hospital.
Initial 50 subjects undergoing directional coronary atherectomy of de novo left anterior descending stenoses at The Toronto Hospital from July 1990 to April 1991.
Directional coronary atherectomy according to standard interventional techniques, with pre- and post procedure qualitative evaluation and quantitative coronary arteriography (Cardiac Measurement System; Leiden, The Netherlands) to define angiographic outcome.
Comparing 'early' (group 1) versus 'late' (group 2) subjects, baseline demographics and clinical parameters were similar. Later subjects demonstrated increased coronary tortuosity (group 1, 1.40 versus group 2, 1.64, P < 0.01) and major side branch involvement within the stenosis (group 1, seven of 25 [28%] versus group 2, 18 of 25 [72%], P < 0.01). Regardless of experience, post procedure residual minimum stenotic diameters were equal (group 1, 2.75 +/- 0.55 versus group 2, 2.49 +/- 0.42 mm) in progressively longer lesions (group 1, 11.4 +/- 4.9 versus group 2, 13.3 +/- 5.5 mm, P < 0.1), with increased symmetry (group 1, 0.60 +/- 0.28 versus group 2, 0.73 +/- 0.19, P < 0.05). Analysis of consecutive pentiles (10 subjects per group) indicated gradual increases in post procedure residual lumen during early experience (the first 30 subjects), with an abrupt deterioration in outcome (fourth pentile), secondary to qualitative changes in coronary anatomy, before a return to satisfactory residual minimum stenotic diameters (fifth pentile).
This study defines a distinct 'learning curve' during the initial 30 patients undergoing directional coronary atherectomy, with subtle changes in case selection, predominantly reflected by qualitative indices (eg, tortuosity, dystrophic calcification), resulting in a transient deterioration in final outcomes (patient 31 to 40). Subsequently, optimal results were re-established after defining appropriate case selection criteria, in conjunction with progressive expertise.
评估定向冠状动脉斑块旋切术不断演变的选择标准及血管造影结果（“学习曲线”）。
三级转诊的大学附属医院。
1990年7月至1991年4月在多伦多医院接受原发性左前降支狭窄定向冠状动脉斑块旋切术的最初50例患者。
根据标准介入技术进行定向冠状动脉斑块旋切术，术前和术后进行定性评估及定量冠状动脉造影（心脏测量系统；荷兰莱顿）以确定血管造影结果。
比较“早期”（第1组）与“晚期”（第2组）患者，基线人口统计学和临床参数相似。晚期患者的冠状动脉迂曲度增加（第1组为1.40，第2组为1.64，P<0.01），且狭窄部位主要分支受累情况更严重（第1组25例中有7例[28%]，第2组25例中有18例[72%]，P<0.01）。无论经验如何，在病变逐渐变长的情况下（第1组为11.4±4.9，第2组为13.3±5.5mm，P<0.1），术后残余最小狭窄直径相等（第1组为2.75±0.55，第2组为2.49±0.42mm），且对称性增加（第1组为0.60±0.28，第2组为0.73±0.19，P<0.05）。对连续五分位数（每组10例患者）的分析表明，在早期经验（最初30例患者）期间，术后残余管腔逐渐增加，在第4个五分位数时结果突然恶化，这是由于冠状动脉解剖结构的定性变化所致，之后又恢复到令人满意的残余最小狭窄直径（第5个五分位数）。
本研究确定了在最初30例接受定向冠状动脉斑块旋切术的患者中存在一条明显的“学习曲线”，病例选择存在细微变化，主要由定性指标（如迂曲度、营养不良性钙化）反映，导致最终结果出现短暂恶化（第31至40例患者）。随后，在确定合适的病例选择标准并结合不断提高的专业技能后，重新建立了最佳结果。
