Functional Assessment of Myocardial Ischemia by Intracoronary Electrocardiogram
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 100
- 试验地点
- 1
- 主要终点
- Intracoronary Electrocardiogram ST-Segment Shift
研究概览
简要总结
In patients with chronic stable coronary artery disease (CAD), percutaneous coronary intervention (PCI) targets hemodynamically significant coronary lesions, i.e., those thought to cause inducible ischemia. The hemodynamic severity of a coronary stenosis increases with its tightness and with the myocardial mass of viable myocardium downstream of the stenosis.
Compared to the traditional anatomic angiographic approach, assessment of functional relevance by fractional flow reserve (FFR) during coronary angiography has been suggested to improve patient outcomes. Fractional flow reserve (FFR) is based on determination of the coronary perfusion pressure downstream of a stenosis during pharmacologic hyperemia. However, FFR relies on oversimplified physiologic concepts, which limits its usefulness in defining a true ischemic threshold. Furthermore, visual angiographic assessment continues to dominate the treatment decisions for intermediate coronary lesions.
Conversely, the intracoronary ECG (icECG) provides an inexpensive, sensitive and direct measure of myocardial ischemia. The icECG is easily acquired by attaching a reusable alligator clamp to a conventional angioplasty guidewire (at one tenth the price of a pressure sensor guidewire). The coronary guide wire positioned downstream of a coronary stenosis then acts as the exploring electrode. During pharmacologic stress, the icECG can provide direct evidence for regional myocardial ischemia to define the ischemic threshold in different types of coronary artery disease.
详细描述
INVASIVE PRESSURE-DERIVED INDICES OF STENOSIS SEVERITY
In the setting of stable coronary artery disease (CAD), PCI or coronary artery bypass grafting (CABG) targets coronary lesions causing inducible myocardial ischemia. With the advancement of technology, the development of a coronary pressure guide wire enabled to reliably measure coronary perfusion pressure downstream of a stenosis and therefore trans-stenotic pressure gradients. On the basis of comparisons to noninvasive stress tests, the concept of fractional flow reserve (FFR) was introduced. FFR determines the ratio of mean distal coronary pressure and mean aortic pressure (the effective coronary perfusion pressure) during (pharmacologic) hyperemia. A FFR value of near 1 is then equivalent to a totally normal coronary artery, whereas a cutoff of 0.75-0.80 is commonly used to determine that PCI is warranted.
With FFR, pharmacologic hyperemia is mandatory to induce minimal and constant myocardial resistance, which is the basis to directly relate coronary pressure and flow.In contrast, the recently introduced concept of the instantaneous wave-free ratio (iFR) claims to obviate the need for administration of pharmacologic stress. Instead, coronary pressure is analyzed at rest and during part of coronary diastole, when myocardial resistance is thought to be naturally constant and minimal (the so called wave-free period).
LIMITATIONS OF PRESSURE-DERIVED INDICES OF STENOSIS SEVERITY IN DEFINING THE ISCHEMIC THRESHOLD
A major limitation of pressure-derived indices of stenosis severity is related to the assumption of oversimplified physiologic concepts. Clinically, the diagnostic accuracy of FFR is restricted in three scenarios. Firstly, the pressure gradient evaluated by FFR is critically dependent on the magnitude of resistance offered by the microcirculation. With microvascular dysfunction, microvascular resistance remains inadequately high during pharmacologic hyperemia, meaning that the pressure gradient across the stenosis does not reflect the epicardial stenosis severity (overestimation of FFR).
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Diagnostic
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Age > 18 years
- •Referred for elective coronary angiography
- •Written informed consent to participate in the study
排除标准
- •Acute coronary syndrome
- •Severe aortic stenosis
- •Acute congestive heart failure NYHA III-IV
- •Prior myocardial infarction in the vascular territory undergoing pressure measurements
- •Presence of left bundle branch block, non-sinus rhythm or paced rhythm in resting ECG
- •Coronary anatomy unsuitable for coronary pressure measurements
- •Severe pulmonary, renal or hepatic disease
- •Contraindication to inotropic stress
- •Women of childbearing age
结局指标
主要结局
Intracoronary Electrocardiogram ST-Segment Shift
时间窗: Measured at maximal heart frequency (=~6min after begin dobutamine)
Change in intracoronary ST-segment shift from baseline to hyperemia, measured at the J-Point in mV
次要结局
- Percent Diameter Stenosis(During diagnostic angiography at the beginning of the coronary angiography)
- Fractional Flow Reserve(Measured at maximal heart frequency (=~6min after begin dobutamine))
- Instantaneous wave-free ratio(Measured at baseline before inotropic stress)
- Area at Risk(Measured after the coronary angiography, expected to be on average after 3 days)