Coronary Flow-Pressure Relationship Distal to Epicardial Stenosis

Tanaka, Nobuhiro; Takazawa, Kenji; Takeda, Kazuhiro; Aikawa, Masanori; Shindo, Naohisa; Amaya, Kazutaka; Kobori, Yuichi; Yamashina, Akira

doi:10.1253/circj.67.525

Cited by 10 publications

(8 citation statements)

References 16 publications

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“…In the diastolic phase of the cardiac cycle, the coronary flow velocity is substantially increased compared with the systolic phase. 11 Thus, the coronary flow velocity of the diastolic phase should be higher than the mean of the whole-cycle phase. Regarding the reason why the iFR is a better index than the Pd/Pa, it is plausible that it is derived from the difference in the coronary flow velocity.…”

Section: Discussionmentioning

confidence: 99%

Hyperemic Instantaneous Wave-Free Ratio Provides the Hemodynamic Outcome for Moderate to Severe Coronary Artery Stenoses

Kanamori¹,

Yoshikawa²,

Aikawa³

2016

J.ATAMIS

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Background: The fractional flow reserve (FFR) has been established as a physiological tool for the assessment of coronary ischemia. The instantaneous wave-free ratio (iFR) is an alternative pressure-derived physiologic index from the diastolic wave-free period in stable conditions. The hyperemic iFR (h-iFR) may represent a diagnostic tool; however, its diagnostic performance is unclear. Thus, we aimed to assess the diagnostic performance of the h-iFR compared with the conventional whole-cycle FFR. Methods: Fifty consecutive lesions, which were diagnosed as 50-75% stenosis by coronary angiography, were analyzed regarding the h-iFR and FFR during the intravenous administration of adenosine using a pressure wire. The h-iFR and FFR were calculated via automated algorithms.Results: Twenty-two stenoses were positive (FFR ≦0.8), and 28 stenoses were negative (FFR >0.8). The slope of the regression line was 1.28 in the positive group and 1.61 in the negative group. The FFR and h-iFR values ranged from 0.64 to 0.80 (0.75±0.04) and 0.52 to 0.82 (0.66±0.07), respectively, in the positive group and 0.81 to 1.02 (0.90±0.05) and 0.69 to 1.02 (0.87±0.08), respectively, in the negative group. The means of the differences between the FFR and h-iFR were 0.027 and 0.090 in the FFR positive and negative groups, respectively. Conclusions: The hyperemic iFR, which is calculated using the diastolic phase and exhibited a larger dynamic range than the FFR, especially in FFR-positive stenosis, may be a better physiological tool than the cardiac full-cycle FFR in the evaluation of coronary ischemia.

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Section: Discussionmentioning

confidence: 99%

Hyperemic Instantaneous Wave-Free Ratio Provides the Hemodynamic Outcome for Moderate to Severe Coronary Artery Stenoses

Kanamori¹,

Yoshikawa²,

Aikawa³

2016

J.ATAMIS

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“…Tanaka et al (37) described this relationship during hyperemia. The slope of the curve in diastole and the X-intercept changed significantly during maximal hyperemia induced by papaverine administration.…”

Section: H404 Assessment Of Coronary Microcirculation In a Swine Modelmentioning

confidence: 93%

Assessment of coronary microcirculation in a swine animal model

Zhang

Takarada

Molloi

2011

American Journal of Physiology-Heart and Circulatory Physiology

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Coronary microvascular dysfunction has important prognostic implications. Several hemodynamic indexes, such as coronary flow reserve (CFR), microvascular resistance, and zero-flow pressure (Pzf), were used to establish the most reliable index to assess coronary microcirculation. Fifteen swine were instrumented with a flow probe, and a pressure wire was advanced into the distal left anterior descending artery. Adenosine was used to produce maximum hyperemia. Microspheres were used to create microvascular dysfunction. An occluder was used to produce stenosis. Blood flow from the probe (Q p), aortic pressure, distal coronary pressure, and right atrium pressure were recorded. Angiographic flow (Q a) was calculated using a time-density curve. Flow probe-based CFR and angiographic CFR were calculated using Q p and Q a, respectively. Flow probe-based (NMRqh) and angiographic normalized microvascular resistance (NMRah) were determined using Q p and Q a, respectively, during hyperemia. Pzf was calculated using Q p and distal coronary pressure. Two series of receiver operating characteristic curves were generated: normal epicardial artery model (N model) and stenosis model (S model). The areas under the receiver operating characteristic curves for flow probe-based CFR, angiographic CFR, NMRqh, NMRah, and Pzf were 0. 855, 0.836, 0.976, 0.956, and 0.855 in N model and 0.737, 0.700, 0.935, 0.889, and 0.698 in S model. Both NMRqh and NMRah were significantly more reliable than CFR and Pzf in detecting the microvascular deterioration. Compared with CFR and Pzf, NMR provided a more accurate assessment of microcirculation. This improved accuracy was more prevalent when stenosis existed. Moreover, NMRah is potentially a less invasive method for assessing coronary microcirculation.angiography; blood flow; cardiovascular imaging; coronary microvascular function CORONARY ANGIOGRAPHY, a routine examination for patients with heart disease, provides an assessment of stenosis severity by visualizing the opacified arterial lumen. However, in many cases (12,40), the severity of myocardium ischemia correlates poorly with epicardial stenosis. Therefore, intracoronary physiological techniques have been developed to provide physiological evaluations for patients who undergo coronary angiography (8,34). Recently, the medical community's interest in coronary microcirculation has grown with the increasing awareness that microvascular dysfunction occurs in a number of myocardial disease states and has important prognostic implications (19,20). With this recognition comes the need for a method to accurately assess the functional capacity of coronary microcirculation for diagnostic purposes and to monitor the effects of therapeutic interventions targeted at reversing the extent of coronary microvascular dysfunction. To assess changes in the microcirculatory bed, several indexes have been proposed, such as coronary flow reserve (CFR), microvascular resistance (MR), and zero-flow pressure (P zf ). In the early 1990s, Gould et al. (14) introduced CFR...

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“…In patients with left ventricular hypertrophy (LVH) and diabetes, the ischemic threshold is lower as a result of relatively inadequate blood supply to the myocardium. 28, 29 Furthermore, an increased perfusion gradient is noted in the myocardium of LVH patients. In such situations, a FFR cutoff value of 0.75 may be inappropriately low.…”

Section: Nakamura Mmentioning

confidence: 99%

Angiography Is the Gold Standard and Objective Evidence of Myocardial Ischemia Is Mandatory If Lesion Severity Is Questionable - Indication of PCI for Angiographically Significant Coronary Artery Stenosis Without Objective Evidence of Myocardial Ischemia (Pro) -

Nakamura

2011

Circ J

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Circulation Journal Official Journal of the Japanese Circulation Society http://www. j-circ.or.jp t present, coronary artery disease (CAD) remains the biggest cause of death. While the mortality rate of acute coronary syndrome (ACS) has declined in recent years, mortality due to stable CAD has been unchanged over the last decades. 1 Medical treatment for CAD aims at stabilization of plaque and prevention of progression, as well as prevention of plaque rupture and subsequent future events, while treating the symptoms and sequelae of the disease. On the other hand, revascularization by either coronary artery bypass surgery or percutaneous coronary intervention (PCI) aims to re-establish effective coronary blood flow, leading to improvement of myocardial ischemia and its manifestations. The indications for PCI have expanded due to recent advances in techniques and the development of new devices. Especially since the approval of drug-eluting stents (DES), use of PCI has expanded for both complex lesions and for mild to moderate stenosis 2 (Figure 1). Recent rapid advances of diagnostic modalities such as coronary CT angiography are likely to contribute to this trend for increased use of PCI. 3,4 Although the data have not been reported, it is speculated that the number of PCI procedures for coronary artery stenosis documented by coronary CT angiography has dramatically increased ( Figure 2). As a result, the appropriateness of current indications for PCI has been called into question, particularly its use in patients lacking documentation of ischemia by noninvasive testing prior to the procedure. Here, I will discuss the importance of evaluating the extent of CAD and the indications for PCI in CAD patients. Coronary Angiography (CAG) Is the Gold Standard for Evaluation of LesionsCAG has long been the gold standard for evaluation of CAD. However, the limitations of CAG have also been clearly demonstrated by intravascular ultrasound studies and autopsy studies. 5-7 Because angiographic assessment is based on visualizing the vessel lumen, complex lesions (such as diffuse lesions, bifurcation lesions, and slit-like lesions) are not ideal for evaluation of severity by CAG. These lesions are difficult to visualize angiographically, even if multiple projections are employed. Therefore, the clinical importance of physiological assessment as an adjunct to CAG for evaluation of The indications for percutaneous coronary intervention (PCI) have expanded, especially after the approval of drugeluting stents, for both complex lesions and those with intermediate stenosis.Because recent randomized trials have demonstrated the non-inferiority of optimal medical treatment for stable angina compared with coronary revascularization, and the benefits of PCI guided by coronary pressure measurement have been shown in another trial, the appropriateness of current indications for PCI has been called into question. In the evaluation of coronary artery stenosis, inter- and intraobserver variabilities can be problematic. Therefore, the use of P...

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Coronary Flow-Pressure Relationship Distal to Epicardial Stenosis

Cited by 10 publications

References 16 publications

Hyperemic Instantaneous Wave-Free Ratio Provides the Hemodynamic Outcome for Moderate to Severe Coronary Artery Stenoses

Hyperemic Instantaneous Wave-Free Ratio Provides the Hemodynamic Outcome for Moderate to Severe Coronary Artery Stenoses

Assessment of coronary microcirculation in a swine animal model

Angiography Is the Gold Standard and Objective Evidence of Myocardial Ischemia Is Mandatory If Lesion Severity Is Questionable - Indication of PCI for Angiographically Significant Coronary Artery Stenosis Without Objective Evidence of Myocardial Ischemia (Pro) -

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