In vitro and in vivo studies on thermistor‐based intracoronary temperature measurements: Effect of pressure and flow

Cuisset, Thomas; Beauloye, Christophe; Melikian, Narbeh; Hamilos, Michalis; Sarma, Jaydeep; Sarno, Giovanna; Näslund, Maria; Smith, Leif; Vosse, F.N. van de; Pijls, Nico H.J.; Bruyne, Bernard De

doi:10.1002/ccd.21780

Cited by 24 publications

(12 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Further, a recent study showed that variations in coronary pressure and blood flow alter the temperature measurements with a thermistor, and temperature elevations observed in previous studies may have been due to artifact. 60 This study raises the validity of the findings on all previous thermography studies.…”

Section: Thermographysupporting

confidence: 67%

Intravascular Detection of the Vulnerable Plaque

Suh

Seto

Margey

et al. 2011

Circ: Cardiovascular Imaging

View full text Add to dashboard Cite

C oronary heart disease (CHD) remains the leading cause of death in the United States, and an estimated 1.4 million Americans have a heart attack each year. Over the past 2 decades, the concept of the "vulnerable plaque" (VP) being responsible for the majority of acute coronary syndromes (ACS) has become widely accepted. Coincidentally, there has been rapid expansion of coronary imaging modalities, both invasive and noninvasive, seeking the ability to detect high-risk plaques before their disruption and formation of occlusive thrombus. Histological characteristics of the plaques that are vulnerable to rupture are thin fibrous cap (Ͻ65 m), large lipid pool, and activated macrophages near the fibrous cap, all of which can be detected with highresolution coronary imaging. 1 Cellular mechanisms associated with plaque instability include inflammation, reduced collagen synthesis, local overexpression of collagenase, and smooth muscle cell apoptosis. These pathological processes can alter the plaque surface and its mechanical properties, which also have been targets of recent research. Noninvasive tests, such as CT and MRI are limited by low resolution and are unable to visualize most of the features of VP. At present, only intravascular modalities can potentially distinguish VP from benign types of plaques. In this review, we focus on the recent data from the various types of intravascular modalities currently available or in development and compare their advantages and limitations. Invasive Imaging TechniquesCoronary plaque develops eccentrically, and increasing plaque volume induces positive remodeling of the vessel, resulting in external elastic membrane expansion and preservation of luminal area. Coronary angiography only visualizes the coronary lumen and does not provide any information about the characteristics of the arterial wall and its contents. For this reason, coronary angiography has failed as a diagnostic modality for detection of VP, which often causes only modest luminal narrowing.Various histological plaque components have been targeted as potential candidates for plaque vulnerability. These candidate features and comparisons of the invasive imaging modalities are listed in the Table. 2 The characteristic architecture of a thin-cap fibroatheroma (TCFA) overlying a lipid pool has promoted further enhancements in high-resolution imaging modalities, including integrated backscatter intravascular ultrasound (IB-IVUS), virtual histology IVUS (VH-IVUS), optical coherence tomography (OCT), and intravascular MRI (IV-MRI). Plaque composition also affects the response of the vessel wall to pulsatile changes in blood pressure, and the mechanical strain patterns can be measured with elastography and palpography. The cholesterol-rich lipid core underlying the fibrous cap is identifiable by angioscopically detected color changes reflected on the plaque surface and by the unique absorption of energy of its cholesterol crystals, leading to the development of Raman spectroscopy (RS) and near-infrared spectroscopy (NIR...

show abstract

Section: Thermographysupporting

confidence: 67%

Intravascular Detection of the Vulnerable Plaque

Suh

Seto

Margey

et al. 2011

Circ: Cardiovascular Imaging

View full text Add to dashboard Cite

show abstract

“…Mean temperature difference measured in the culprit lesion was 0.02°±0.01°C, which was below the resolution of the thermistor and not significantly different from the baseline temperature difference of 0.00°±0.01°C. In a recent article, Cuisset et al [26], by using the same system, showed that when the sensor was advanced across the lesion, an increase in the temperature signal (average 0.059°±0.028°C) was uniformly observed in all patients. However, the increase in the temperature signal was proportional to the pressure drop across the stenosis [26].…”

Section: Human In Vivo Intracoronary Thermography Studiesmentioning

confidence: 96%

“…In a recent article, Cuisset et al [26], by using the same system, showed that when the sensor was advanced across the lesion, an increase in the temperature signal (average 0.059°±0.028°C) was uniformly observed in all patients. However, the increase in the temperature signal was proportional to the pressure drop across the stenosis [26]. This study suggested that thermistor-based sensors may not be suited for assessing in vivo coronary thermal heterogeneity.…”

Section: Human In Vivo Intracoronary Thermography Studiesmentioning

confidence: 96%

“…For flow values larger than 60 mL/min, the pressure wire could not detect any significant increase in temperature when passed in front of the "hot spot." An inverse correlation was observed between the flow and the observed temperature changes [26]. On the basis of these studies, to assess the possible influence of coronary blood flow, temperature measurements have been performed during complete interruption of flow [48].…”

Section: Effect Of Blood Flow On Coronary Temperature Measurementmentioning

confidence: 99%

See 1 more Smart Citation

Intravascular Thermography for Assessing Vulnerable Plaques

Toutouzas

Drakopoulou

Synetos

et al. 2010

curr cardiovasc imaging rep

View full text Add to dashboard Cite

Atherosclerosis and its cardiovascular complications remain the leading cause of death in developed countries. Current knowledge of coronary artery disease progression has significantly evolved and the interest has been focused on the development of new imaging techniques for the early detection of vulnerable lesions. Intracoronary thermography is a method that detects local plaque inflammation. Clinical studies with intracoronary thermography have enlightened the diagnostic algorithm of high-risk or "vulnerable" plaque. The current shortcomings, however, of intracoronary thermography limit the clinical application of the method. Future technological achievements will hopefully lead to the detection of inflamed plaques, thus determining the role of inflammation in plaque destabilization and directing local and/or systemic therapy in patients with coronary artery disease.

show abstract

“…In the current study, the issue of pressure is also demonstrated only in low flow circumstances. It would be helpful if blood flow was kept normal and obtain temperature measurements during changes of pressure [1].The interpretation of the results of the study, however, can be performed by considering the following concerns. Initially, the authors attempt to explain the findings of other in vitro and in vivo experimental and clinical studies on atheromatic plaque temperature measurements, by blood temperature measurements in the mentioned model.…”

mentioning

confidence: 99%

Regarding the study in vitro and in vivo studies on thermistor‐based intracoronary temperature measurements: Effect of pressure and flow

Toutouzas¹,

Tsiamis²,

Drakopoulou³

et al. 2009

Cathet Cardio Intervent

View full text Add to dashboard Cite

Regarding the Study In Vitro and In Vivo Studies on Thermistor-Based Intracoronary Temperature Measurements: Effect of Pressure and Flow TO THE EDITOR Cuisset et al. published an interesting study regarding the effect of flow and pressure on thermistor-based temperature measurements [1]. The authors used two models for studying the effect of pressure and flow on blood temperature measurements: a low flow/low pressure and a low flow/normal pressure model. They conclude that the temperature measurements are markedly influenced by the pressure and to a much lesser extent by the flow of blood, as when pressure was normal a modest increase was found in blood temperature, whereas in low pressure a relatively slow increase in mean temperature signal was observed.The authors provide significant information regarding the potential confounders of in vivo temperature measurements. Indeed, several studies have shown that intravascular thermography measurements are affected by flow and morphologic characteristics of the atherosclerotic plaque [2][3][4]. In the current study, the issue of pressure is also demonstrated only in low flow circumstances. It would be helpful if blood flow was kept normal and obtain temperature measurements during changes of pressure [1].The interpretation of the results of the study, however, can be performed by considering the following concerns. Initially, the authors attempt to explain the findings of other in vitro and in vivo experimental and clinical studies on atheromatic plaque temperature measurements, by blood temperature measurements in the mentioned model. The results of the current study on blood temperature measurements, cannot explain all previous studies in atheromatic plaques. Then, despite the multiple potential confounders (pressure, flow, plaque morphology, etc.) on intravascular thermography, the ex vivo temperature values of Casscells et al. were not reached by any thermistor or catheter design [5]. These findings were verified by infrared thermographic images that also revealed heterogeneity in temperature in atheromatic plaques [5]. Thus, all potential con-Conflict of interest: Nothing to report.

show abstract

In vitro and in vivo studies on thermistor‐based intracoronary temperature measurements: Effect of pressure and flow

Abstract: Taken together these observations suggest that thermistor-based sensors are not suited for assessing thermal heterogeneity in the vascular wall and that the data obtained so far in patients with acute coronary syndromes might have been flawed by pressure (and flow) artifacts.

Cited by 24 publications

References 16 publications

Intravascular Detection of the Vulnerable Plaque

Intravascular Detection of the Vulnerable Plaque

Intravascular Thermography for Assessing Vulnerable Plaques

Regarding the study in vitro and in vivo studies on thermistor‐based intracoronary temperature measurements: Effect of pressure and flow

Contact Info

Product

Resources

About