We thank all the staff of the catheterization laboratory of the Tohoku University Hospital.

The measurement of myocardial lactate production during ACh provocation testing to evaluate coronary vasoreactivity was conducted following the ethical principles in the Declaration of Helsinki, and the protocol was approved by the Ethics Committees of Tohoku University (No.2016-1-643). All the patients provided written informed consent before the procedure. In this article, ACh provocation testing was performed following the guidelines of the Japanese Circulation Society9.
1. Preparation for the procedure
<ol>
	<li>Ensure that the measurement of myocardial lactate production is performed in patients undergoing ACh provocation testing to diagnose VSA and/or microvascular angina (MVA) due to vasospasm.</li>
	<li>Ensure that the patients discontinue all vasoactive agents for accuracy of those diagnoses, including calcium channel blockers, long-acting nitrates, and nicorandil, at least 48 h before catheterization study9.</li>
	<li>Do shave hair at puncture sites, including both inguinal regions and wrists.</li>
</ol>
2. Insertion of catheters before ACh provocation testing
<ol>
	<li>Use local anesthesia at puncture sites with subcutaneous 1% lidocaine to insert intravenous and radial artery sheaths. 
	NOTE: The anesthesia effect is confirmed by the loss of pain sensation at the anesthetized area by pricking with a needle.</li>
	<li>Place two 5 Fr venous sheaths through the right or left femoral vein with ultrasound guidance. 
	NOTE: One venous sheath is used to insert a temporary pacing electrode in the right ventricle in case of severe bradycardia after intracoronary ACh. The other one is for a CS catheter to obtain blood samples to measure lactate levels in the CS.</li>
	<li>Place a 5 or 6 Fr arterial sheath through the radial or femoral artery.</li>
	<li>Administer intravenous heparin (50 to 70 U/kg) to achieve therapeutic anticoagulation (activated clotting time ~250 s) before coronary instrumentation.</li>
	<li>Canulate a 5 Fr or 6 Fr Judkins-left catheter into LCA through the radial or femoral artery. 
	NOTE: The usual catheter manipulations are performed with the Judkins left catheter.</li>
	<li>Advance a CS catheter, for often a hydrophilic coating Amplatz-left catheter is used, from a venous sheath placed at the right femoral vein to the right atrium.</li>
	<li>Confirm the configuration of CS and the location of its orifice in the right atrium in advance by detecting the CS image in the venous phase of LCA angiography (Figure 1A).</li>
	<li>Canulate an Amplatz-left catheter into CS by turning the catheter counterclockwise at the right atrium with the left anterior oblique (LAO) view.</li>
	<li>Verify whether the catheter is cannulated into CS and its position in CS is adequate by contrast injection from the end of the catheter (Figure 1B). 
	NOTE: The venous phase of the LCA angiography confirms whether the catheter is cannulated into CS.</li>
	<li>Take a pair of blood samples from the CS and the ostium of LCA simultaneously to examine myocardial lactate metabolism at baseline. Then, measure lactate levels in those samples using blood gas analysis equipped with automatic lactate measurement function.</li>
</ol>
3. Measurement of myocardial lactate production during ACh provocation testing
<ol>
	<li>Perform the baseline left coronary angiography in an appropriate projection that ensures the best separation of the branches of each coronary artery, and serial angiographies after intracoronary injection of ACh should be performed in the same projection. 
	NOTE: Since the great coronary sinus drains blood from perfusion regions of the LCA but not from the right coronary artery, evaluation of myocardial lactate production is possible only for the LCA during ACh provocation testing8,10.</li>
	<li>Administer ACh into the coronary artery in a cumulative manner (ACh 20, 50, and 100 &#181;g in 10 mL of solution) over 20 s with careful monitoring of blood pressure and 12-lead electrocardiography (ECG). Perform coronary angiography when chest pain or any ECG ST-segment change occurs, or routinely after completing each ACh injection9,11.</li>
	<li>Collect paired samples of 1 mL of blood from the LCA ostium and the CS to measure lactate concentrations at 1 min after each dose of ACh is given to LCA and determine lactate concentrations with a calibrated automatic lactate analyzer.</li>
	<li>Calculate the lactate extraction ratio (LER) by dividing the coronary arteriovenous difference in the lactate concentration by the arterial lactate concentration as follows4,8,10: 
	LER = (arterial lactate concentration [mmol/L] - coronary venous lactate concentration [mmol/L])/arterial lactate concentration (mmol/L). 
	&#8203;NOTE: Myocardial lactate production defined by negative LER is objective evidence to support the emerging myocardial ischemia4,8,10. Therefore, the occurrence of MVS as myocardial lactate production (negative LFR) becomes recognizable without or before the occurrence of angiographically apparent epicardial coronary spasm during ACh provocation testing3.</li>
	<li>Administer 5 mg of isosorbide dinitrate into the LCA if epicardial coronary spasms were induced. Promptly, perform coronary angiography while the coronary artery is maximally dilated.
	<ol>
		<li>Simultaneously, collect blood samples of 1 mL of blood from the LCA ostium and the CS to measure lactate concentrations after the relief of ACh-induced spasm.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Kunadian, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+EAPCI+expert+consensus+document+on+ischaemia+with+non-obstructive+coronary+arteries+in+collaboration+with+European+Society+of+Cardiology+Working+Group+on+Coronary+Pathophysiology+&amp;+Microcirculation+endorsed+by+Coronary+Vasomotor+Disorders+International+Study+Group.">An EAPCI expert consensus document on ischaemia with non-obstructive coronary arteries in collaboration with European Society of Cardiology Working Group on Coronary Pathophysiology &amp; Microcirculation endorsed by Coronary Vasomotor Disorders International Study Group.</a> European Heart Journal. 41 (37), 3504-3520 (2020).</li><li>Ong, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diagnosis+of+coronary+microvascular+dysfunction+in+the+clinic.">Diagnosis of coronary microvascular dysfunction in the clinic.</a> Cardiovascular Research. 116 (4), 841-855 (2020).</li><li>Mohri, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Angina+pectoris+caused+by+coronary+microvascular+spasm.">Angina pectoris caused by coronary microvascular spasm.</a> Lancet. 351 (9110), 1165-1169 (1998).</li><li>Sun, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coronary+microvascular+spasm+causes+myocardial+ischemia+in+patients+with+vasospastic+angina.">Coronary microvascular spasm causes myocardial ischemia in patients with vasospastic angina.</a> Journal of the American College of Cardiology. 39 (5), 847-851 (2002).</li><li>Ong, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=International+standardization+of+diagnostic+criteria+for+microvascular+angina.">International standardization of diagnostic criteria for microvascular angina.</a> International Journal of Cardiology. 250, 16-20 (2018).</li><li>Matsuyama, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+plasma+level+of+endothelin-1-like+immunoreactivity+during+coronary+spasm+in+patients+with+coronary+spastic+angina.">Increased plasma level of endothelin-1-like immunoreactivity during coronary spasm in patients with coronary spastic angina.</a> American Journal of Cardiology. 68 (10), 991-995 (1991).</li><li>Goldberg, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coronary+hemodynamic+and+myocardial+metabolic+alterations+accompanying+coronary+spasm.">Coronary hemodynamic and myocardial metabolic alterations accompanying coronary spasm.</a> American Journal of Cardiology. 43 (3), 481-487 (1979).</li><li>Odaka, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasma+concentration+of+serotonin+is+a+novel+biomarker+for+coronary+microvascular+dysfunction+in+patients+with+suspected+angina+and+unobstructive+coronary+arteries.">Plasma concentration of serotonin is a novel biomarker for coronary microvascular dysfunction in patients with suspected angina and unobstructive coronary arteries.</a> European Heart Journal. 38 (7), 489-496 (2017).</li><li>J. C. S. Joint Working Group. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Guidelines+for+diagnosis+and+treatment+of+patients+with+vasospastic+angina+(Coronary+Spastic+Angina)+(JCS+2013).">Guidelines for diagnosis and treatment of patients with vasospastic angina (Coronary Spastic Angina) (JCS 2013).</a> Circulation Journal. 78 (11), 2779-2801 (2014).</li><li>Kaikita, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determinants+of+myocardial+lactate+production+during+acetylcholine+provocation+test+in+patients+with+coronary+spasm.">Determinants of myocardial lactate production during acetylcholine provocation test in patients with coronary spasm.</a> Journal of American Heart Association. 4 (12), (2015).</li><li>Sueda, S., Kohno, H., Ochi, T., Uraoka, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overview+of+the+acetylcholine+spasm+provocation+test.">Overview of the acetylcholine spasm provocation test.</a> Clinical Cardiology. 38 (7), 430-438 (2015).</li></ol>

H.S. received lecture fees from Bayer Yakuhin, Ltd. and Daiichi Sankyo Co. Ltd., but declares no conflicts of interest regarding the present work. All the other authors have nothing to disclose.

Detection of enhanced coronary vasoconstriction is possible by an additional pharmacological provocation testing with ACh or ergometrine during coronary angiography. Even now, there is no technique to directly visualize the coronary microvasculature for evaluation of its function in vivo, the occurrence of coronary spasm at microvascular level could be solely deduced by the reproduction of usual symptoms together with ischemic ECG changes despite the absence of epicardial coronary spasm during ACh provocation te...

Recent studies demonstrated that ischemia with non-obstructive coronary arteries (INOCA) is caused mainly by functional coronary vasomotion disorders, including epicardial and microvascular spasms1. The diagnosis of coronary vasoconstrictor dysfunction at the epicardial and/or microvascular levels often requires intracoronary provocation testing with a pharmacological vasoactive agent such as acetylcholine (ACh) during coronary angiography2. Many patients with INOCA have no epicardial spasm on coronary arteriography despite the development of angina attack and ischemic electrocardiographic (ECG) changes in response to intracoronary ACh3. Since the pressure-rate product is almost identical at rest and the onset of attack in those patients, the decrease in coronary blood flow rather than increased myocardial oxygen consumption is likely to explain myocardial ischemia, indicating a substantial involvement with coronary microvascular spasm (MVS). Additionally, MVS also seems to be involved in angina in a quarter of patients with vasospastic angina (VSA) due to epicardial coronary spasm4.
Since no technique is available for visualizing coronary microvessels in humans in vivo, MVS is defined as ischemic ECG changes associated with the reproduction of usual chest pain in the absence of epicardial spasm (90%) intracoronary provocation testing5. Usually, upon the development of ischemia, myocardial lactate consumption decreases, and a shift to lactate production occurs as myocardial ischemia increases in severity6,7. Thus, an additional myocardial lactate production measurement is considered to be useful in confirming ACh-induced microvascular myocardial ischemia during provocation testing3,4,8. Here, the current protocol presents coronary sinus (CS) lactate measurements for the diagnosis of MVS.

<table><tbody><tr><td>ABL8000 FLEX blood gas analyzer</td><td>RADIOMETER, Copenhagen, Denmark</td><td>k041874</td><td>The automatic lactate analyzer</td></tr><tr><td>OUTLOOK</td><td>Terumo Corp, Tokyo, Japan</td><td>RQ-5JL4000</td><td>The Judkins-left catheter for coronary angiography</td></tr><tr><td>Ovisot for injection</td><td>Daiichi sankyo company, limited, Tokyo, Japan</td><td>871232</td><td>Injectable product of acetylcholine chloride for acetylcholine provocation testing</td></tr><tr><td>Supersheath</td><td>MEDIKIT CO., LTD., Tokyou, Japan</td><td>CS50P11TSM</td><td>The sheath for insertion of a catheter</td></tr><tr><td>Technowood SoftNAV Catheter</td><td>Technowood Corp, Tokyo, Japan</td><td>H710-FL445SH</td><td>The Amplatz-left catheter for blood sampling from coronary sinus</td></tr></tbody></table>

measurement of myocardial lactate production for diagnosis of coronary microvascular spasm

In about a quarter of patients with angina and non-obstructive coronary arteries, no epicardial spasm is noted on coronary arteriography during an angina attack. Since the pressure-rate product is almost identical at rest and the onset of attack in those patients, the decrease in coronary blood flow rather than increased myocardial oxygen consumption is likely to explain myocardial ischemia, indicating a substantial involvement with coronary microvascular spasm (MVS). Myocardial lactate production, which could be defined as a negative myocardial lactate extraction ratio (ratio of the coronary arterial-venous difference in lactate concentration to arterial concentration), is considered indicative of objective evidence to support the emerging myocardial ischemia. Thus, monitoring of the myocardial lactate production and the emergence of chest pain and ischemic electrocardiographic changes during acetylcholine (ACh) provocation testing is of significant value for detecting the entity of MVS. Practically, 1 min after incremental doses of ACh (20, 50, and 100 &#956;g) are administered into the left coronary artery (LCA), paired samples of 1 mL of blood are collected from the LCA ostium and coronary sinus for measurement of lactate concentration by a calibrated automatic lactate analyzer. Then, the development of MVS could be confirmed by negative myocardial lactate extraction ratio despite the absence of angiographically demonstrable epicardial coronary spasm or before its occurrence throughout ACh provocation testing. In conclusion, assessment of myocardial lactate production is essential and valuable for the diagnosis of MVS.

A 56-year-old woman with no coronary risk factors suffered from transient chest discomfort at rest. She underwent ACh provocation testing and measurement of myocardial lactate production for diagnosis of MVS. As shown in Figure 2, chest pain, ischemic ECG changes, and negative LER were noted immediately following 100 &#181;g of ACh administration into the LCA. Still, no relevant epicardial coronary spasm was observed on angiography. Thus, she was diagnosed as having MVS. Intriguingly, she ha...

Watch this Scientific Journal Video about Measurement of Myocardial Lactate Production for Diagnosis of Coronary Microvascular Spasm at JoVE.com

Measurement of Myocardial Lactate Production for Diagnosis of Coronary Microvascular Spasm

Myocardial lactate production (coronary arterial-venous difference in serum lactate level) during coronary spasm provocation testing is considered as a highly sensitive marker that reflects acetylcholine-induced myocardial ischemia due to microvascular spasm. This article presents the procedures to assess myocardial lactate production for the diagnosis of coronary microvascular spasm.

In about a quarter of patients with angina and non-obstructive coronary arteries, no epicardial spasm is noted on coronary arteriography during an angina ...

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Research

JoVE Journal

Medicine

1.3K Views.  Tohoku University Graduate School of Medicine. Beoordeling van de lactaatproductie van myocard tijdens Ach-provocatietesten is essentieel en haalbaar voor het diagnosticeren van coronaire microvasculaire spasmen. Deze procedure is over het algemeen veilig en eenvoudig voor het detecteren van het optreden van microvasculaire spasmen, die doorgaans niet zichtbaar zijn op een ander beeldvormingsapparaat Voordat u met de procedure begint, moet u ervoor zorgen dat de productie van myocardlactaat wordt gemeten bij patiënten die een acetylcholi...

Video: Measurement of Myocardial Lactate Production for Diagnosis of Coronary Microvascular Spasm

Mapping Metabolism: Monitoring Lactate Dehydrogenase Activity Directly in Tissue

Mapping enzymatic activity in space and time is critical for understanding the molecular basis of cell behavior in normal tissue and disease. In situ metabolic activity assays can provide information about the spatial distribution of metabolic activity within a tissue. We provide here a detailed protocol for monitoring the activity of the enzyme lactate dehydrogenase directly in tissue samples. Lactate dehydrogenase is an important determinant of whether consumed glucose will be converted to energy via aerobic or anaerobic glycolysis. A solution containing lactate and NAD is provided to a frozen tissue section. Cells with high lactate dehydrogenase activity will convert the provided lactate to pyruvate, while simultaneously converting provided nicotinamide adenine dinucleotide (NAD) to NADH and a proton, which can be detected based on the reduction of nitrotetrazolium blue to formazan, which is visualized as a blue precipitate. We describe a detailed protocol for monitoring lactate dehydrogenase activity in mouse skin. Applying this protocol, we found that lactate dehydrogenase activity is high in the quiescent hair follicle stem cells within the skin. Applying the protocol to cultured mouse embryonic stem cells revealed higher staining in cultured embryonic stem cells than mouse embryonic fibroblasts. Analysis of freshly isolated mouse aorta revealed staining in smooth muscle cells perpendicular to the aorta. The methodology provided can be used to spatially map the activity of enzymes that generate a proton in frozen or fresh tissue.

We describe a protocol for mapping the spatial distribution of enzymatic activity for enzymes that generate nicotinatmide adenine dinucleotide phosphate (NAD(P)H) + H+ directly in tissue samples.

Mapping enzymatic activity in space and time is critical for understanding the molecular basis of cell behavior in normal tissue and disease. In situ ...

Biochemistry

In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

The use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that MicroCT provides quantitative high-resolution three-dimensional (3D) anatomical data non-destructively and longitudinally. Most importantly, with the development of a novel preclinical iodinated contrast agent called eXIA160, functional and metabolic assessment of the heart became possible. However, prior to the advent of commercial MicroCT scanners equipped with X-ray flat-panel detector technology and easy-to-use cardio-respiratory gating, preclinical studies of cardiovascular disease (CVD) in small animals required a MicroCT technologist with advanced skills, and thus were impractical for widespread implementation. The goal of this work is to provide a practical guide to the use of the high-speed Quantum FX MicroCT system for comprehensive determination of myocardial global and regional function along with assessment of myocardial perfusion, metabolism and viability in healthy mice and in a cardiac ischemia mouse model induced by permanent occlusion of the left anterior descending coronary artery (LAD).

In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

This method outlines the use of Quantum Micro-Computed Tomography (MicroCT) to assess cardiac morphology, function, perfusion, metabolism and viability with iodinated contrast agent in mice with experimentally-induced myocardial ischemia. The technique can be applied for non-destructive high-throughput longitudinal in vivo imaging of various animal models of human heart disease.

The use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that ...

Bioengineering

Surgical Placement of Catheters for Long-term Cardiovascular Exercise Testing in Swine

This protocol describes the surgical procedure to chronically instrument swine and the procedure to exercise swine on a motor-driven treadmill. Early cardiopulmonary dysfunction is difficult to diagnose, particularly in animal models, as cardiopulmonary function is often measured invasively, requiring anesthesia. As many anesthetic agents are cardiodepressive, subtle changes in cardiovascular function may be masked. In contrast, chronic instrumentation allows for measurement of cardiopulmonary function in the awake state, so that measurements can be obtained under quiet resting conditions, without the effects of anesthesia and acute surgical trauma. Furthermore, when animals are properly trained, measurements can also be obtained during graded treadmill exercise.
Flow probes are placed around the aorta or pulmonary artery for measurement of cardiac output and around the left anterior descending coronary artery for measurement of coronary blood flow. Fluid-filled catheters are implanted in the aorta, pulmonary artery, left atrium, left ventricle and right ventricle for pressure measurement and blood sampling. In addition, a 20 G&#160;catheter is positioned in the anterior interventricular vein to allow coronary venous blood sampling.
After a week of recovery, swine are placed on a motor-driven treadmill, the catheters are connected to pressure and flow meters, and swine are subjected to a five-stage progressive exercise protocol, with each stage lasting 3 min. Hemodynamic signals are continuously recorded and blood samples are taken during the last 30 sec of each exercise stage.
The major advantage of studying chronically instrumented animals is that it allows serial assessment of cardiopulmonary function, not only at rest but also during physical stress such as exercise. Moreover, cardiopulmonary function can be assessed repeatedly during disease development and during chronic treatment, thereby increasing statistical power and hence limiting the number of animals required for a study.

Here we present a protocol to assess cardiopulmonary function in awake swine, at rest and during graded treadmill exercise. Chronic instrumentation allows for repeated hemodynamic measurements uninfluenced by cardiodepressive anesthetic agents.

This protocol describes the surgical procedure to chronically instrument swine and the procedure to exercise swine on a motor-driven treadmill. Early ...

Intracoronary Acetylcholine Provocation Testing for Assessment of Coronary Vasomotor Disorders

Intracoronary acetylcholine provocation testing (ACH-test) is an established method for assessment of epicardial coronary artery spasm in the catheterization laboratory which was introduced more than 30 years ago. Due to the short half-life of acetylcholine it can only be applied directly into the coronary arteries. Several studies have demonstrated the safety and clinical usefulness of this test. However, acetylcholine testing is only rarely applied in the U.S. or Europe. Nevertheless, it has been shown that 62% of Caucasian patients with stable angina and unobstructed coronary arteries on coronary angiography suffer from coronary vasomotor disorders that can be diagnosed with acetylcholine testing. In recent years it has been appreciated that the ACH-test not only assesses the presence of epicardial spasm but that it can also be useful for the detection of coronary microvascular spam. In such cases no epicardial spasm is seen after injection of acetylcholine but ischemic ECG shifts are present together with a reproduction of the patient's symptoms during the test. This article describes the experience with the ACH-test and its implementation in daily clinical routine.

Intracoronary acetylcholine testing has been established for the assessment of epicardial coronary spasm more than 30 years ago. Recently, the focus has shifted towards the microcirculation and it has been shown that microvascular spasm can be detected using ACH-testing. This article describes the ACH-test and its implementation in daily routine.

Intracoronary acetylcholine provocation testing (ACH-test) is an established method for assessment of epicardial coronary artery spasm in the ...

Murine Left Anterior Descending (LAD) Coronary Artery Ligation: An Improved and Simplified Model for Myocardial Infarction

Ischemic heart disease (IHD), or acute coronary syndrome (ACS), is one of the leading causes of death in the United States. IHD is characterized by reduced blood supply to the heart, resulting in the loss of oxygen to and the ensuing necrosis of the heart muscle. The MI model has gained popularity for its use as a short-term ischemia-reperfusion model and a long-term permanent ligation model. Below, we describe a reliable method for the permanent ligation of the LAD. With mouse genetic engineering technology becoming more advanced, and with an increasing availability of quality murine surgical instruments, the mouse has become a popular model for MI surgeries. Our surgical model incorporates the use of an easily reversible anesthetic for the rapid recovery of the mouse; a minimally invasive endotracheal intubation without involving a tracheotomy; and a thoracentesis through the original thoracotomy site without creating an additional incision in the chest, as is done in some other methods, to effectively remove excess blood and air from the chest cavity. This method is comparatively less invasive than other methods, which dramatically reduces surgical and post-surgical complications and mortality and improves reproducibility.

Murine Left Anterior Descending LAD Coronary Artery Ligation: An Improved and Simplified Model for Myocardial Infarction

We provide a reliable method for left anterior descending artery (LAD) ligation in a mouse model. This method is comparatively less invasive than other methods, involving endotracheal intubation, a left-sided thoracotomy approach, and thoracentesis. This method can be used as a model for both acute and chronic myocardial infarction (MI).

Ischemic heart disease (IHD), or acute coronary syndrome (ACS), is one of the leading causes of death in the United States. IHD is characterized by ...

Real-time Pressure-volume Analysis of Acute Myocardial Infarction in Mice

Acute myocardial infarction can lead to acute heart failure and cardiogenic shock. The evaluation of hemodynamics is critical for the evaluation of any potential therapeutic approach directed against acute left ventricular (LV) dysfunction. Current imaging modalities (e.g., echocardiography and magnetic resonance imaging) have several limitations since data on LV pressure cannot directly be measured. LV catheterization in mice undergoing coronary artery occlusion could serve as a novel method for a real-time evaluation of LV function.
At the beginning of the procedure, mice were anesthetized followed by endotracheal intubation. For LV catheterization, the right carotid artery was exposed via middle-neck incision. The catheter was introduced and placed into the LV cavity. Left thoracotomy was conducted and the left main coronary artery (LCA) was ligated. To induce reperfusion, the suture was released after 45 min. Pressure-volume data was recorded at all times.
Ligation of the LCA caused a decrease in LV systolic function as evidenced by a 30% reduction in stroke volume, LV ejection fraction (EF), and cardiac output. Maximum dP/dt as a parameter for LV contractility was also significantly reduced and diastolic function was severely impaired (minimum dP/dt -40%). Reperfusion over a period of 20 min did not lead to a complete recovery of LV function.
Real-time pressure-volume analysis served as a valid procedure for monitoring cardiac function during acute myocardial infarction in mice. Maintaining stable anesthesia and a standardized surgical approach was crucial to ensure valid results. As the early phase of acute myocardial infarction is critical for morbidity and mortality, the delineated method could be beneficial for preclinical evaluation of new strategies for cardioprotection.

Acute myocardial infarction in mice induces acute but incompletely characterized changes in left ventricular (LV) function. LV catheterization in mice undergoing coronary artery occlusion serves as a novel method for a real-time evaluation of LV function.

Acute myocardial infarction can lead to acute heart failure and cardiogenic shock. The evaluation of hemodynamics is critical for the evaluation of any ...

A Sensitive and Specific Quantitation Method for Determination of Serum Cardiac Myosin Binding Protein-C by Electrochemiluminescence Immunoassay

Biomarkers are becoming increasingly more important in clinical decision-making, as well as basic science. Diagnosing myocardial infarction (MI) is largely driven by detecting cardiac-specific proteins in patients' serum or plasma as an indicator of myocardial injury. Having recently shown that cardiac myosin binding protein-C (cMyBP-C) is detectable in the serum after MI, we have proposed it as a potential biomarker for MI. Biomarkers are typically detected by traditional sandwich enzyme-linked immunosorbent assays. However, this technique requires a large sample volume, has a small dynamic range, and can measure only one protein at a time.	
Here we show a multiplex immunoassay in which three cardiac proteins can be measured simultaneously with high sensitivity. Measuring cMyBP-C in uniplex or together with creatine kinase MB and cardiac troponin I showed comparable sensitivity. This technique uses the Meso Scale Discovery (MSD) method of multiplexing in a 96-well plate combined with electrochemiluminescence for detection. While only small sample volumes are required, high sensitivity and a large dynamic range are achieved. Using this technique, we measured cMyBP-C, creatine kinase MB, and cardiac troponin I levels in serum samples from 16 subjects with MI and compared the results with 16 control subjects. We were able to detect all three markers in these samples and found all three biomarkers to be increased after MI. This technique is, therefore, suitable for the sensitive detection of cardiac biomarkers in serum samples.

Measuring biomarkers in complex biological samples is increasingly guiding clinical decision-making. We describe a highly sensitive method to simultaneously measure cardiac myosin binding protein-C, creatine kinase MB, and cardiac troponin I in serum samples from subjects with myocardial infarction and healthy control subjects.

Biomarkers are becoming increasingly more  important in clinical decision-making, as well as basic science. Diagnosing  myocardial infarction (MI) is ...

Biology

Murine Myocardial Infarction Model using Permanent Ligation of Left Anterior Descending Coronary Artery

Myocardial infarction (MI) and acute coronary diseases are among the most prominent causes of death in population with western lifestyle. The murine models of MI with permanent ligation of left-anterior descending (LAD) coronary artery closely mimics MI in humans. Murine models benefit from the extensive genetic engineering available nowadays. Here we propose a reproducible murine surgical model of myocardial infarction by permanent LAD coronary ligation. Our technique comprises anesthesia with ketamine/xylazine that can be rapidly reversed by administration of an antagonist, intubation without tracheotomy for mechanical-assisted ventilation, ventilation with application of extrinsic positive end-expiratory pressure (PEEP) to avoid alveolar collapse, a thoracotomy method limiting to the minimum surgical lesions made to skeletal muscles, and lung inflation without thoracentesis. This method is sparsely invasive, reproducible and reduces post-surgery mortality and complications.

Herein we describe a surgical procedure showing how to achieve permanent ligation of the left-anterior descending coronary artery in mice. This model is of high relevance to investigate the pathophysiology of myocardial infarction and the concomitant biological processes.

Myocardial infarction (MI) and acute coronary diseases are among the most prominent causes of death in population with western lifestyle. The murine ...

Testing Acetylcholine Followed by Adenosine for Invasive Diagnosis of Coronary Vasomotor Disorders

More than 50% of patients with signs and symptoms of myocardial ischemia undergoing coronary angiography have unobstructed coronary arteries. Coronary vasomotor disorders (impaired vasodilatation and/or enhanced vasoconstriction/spasm) represent important functional causes for such a clinical presentation. Although impaired vasodilatation may be assessed with non-invasive techniques such as positron emission tomography or cardiac magnetic resonance imaging, there is currently no reliable non-invasive technique for the diagnosis of coronary spasm available. Thus, invasive diagnostic procedures (IDP) have been developed for the diagnosis of coronary vasomotor disorders including spasm testing as well as assessment of coronary vasodilatation. The identification of the underlying type of disorder (so called endotype) allows the initiation of targeted pharmacological treatments. Despite the fact that such an approach is recommended by the current European Society of Cardiology guidelines for the management of chronic coronary syndromes based on the CorMicA study, comparability of results as well as multicenter trials are currently hampered by major differences in institutional protocols for coronary functional testing. This article describes a comprehensive IDP protocol including intracoronary acetylcholine provocation testing for diagnosis of epicardial/microvascular spasm, followed by Doppler wire-based assessment of coronary flow reserve (CFR) and hyperemic microvascular resistance (HMR) in search of coronary vasodilatory impairment.

Coronary vasomotion disorders represent frequent functional causes of angina in patients with unobstructed coronaries. The underlying mechanism of angina (endotype) in these patients can be determined by a comprehensive invasive diagnostic procedure based on acetylcholine provocation testing followed by Doppler-derived assessment of the coronary flow reserve and microvascular resistance.

More than 50% of patients with signs and symptoms of myocardial ischemia undergoing coronary angiography have unobstructed coronary arteries. Coronary ...

Left Coronary Artery Ligation: A Surgical Murine Model of Myocardial Infarction

Ischemic heart disease and subsequent myocardial infarction (MI) is one of the leading causes of mortality in the United States and around the world. In order to explore the pathophysiological changes after myocardial infarction and design future treatments, research models of MI are required. Permanent ligation of the left coronary artery (LCA) in mice is a popular model to investigate cardiac function and ventricular remodeling post MI. Here we describe a less invasive, reliable, and reproducible surgical murine MI model by permanent ligation of the LCA. Our surgical model comprises of an easily reversible general anesthesia, endotracheal intubation that does not require a tracheotomy, and a thoracotomy. Electrocardiography and troponin measurement should be performed to ensure MI. Echocardiography at day 28 after MI will discern heart function and heart failure parameters. The degree of cardiac fibrosis can be evaluated by Masson's trichrome staining and cardiac MRI. This MI model is useful for studying the pathophysiological and immunological alterations after MI.

Presented here is a surgical procedure for permanent ligation of the left coronary artery in mice. This model can be used to investigate the pathophysiology and associated inflammatory response after myocardial infarction.

Ischemic heart disease and subsequent myocardial infarction (MI) is one of the leading causes of mortality in the United States and around the world. In ...

Measurement of Myocardial Lactate Production for Diagnosis of Coronary Microvascular Spasm

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