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 border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<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...

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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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1.3K Views.  Tohoku University Graduate School of Medicine. 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.

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

FISH for Pre-implantation Genetic Diagnosis

Pre-implantation genetic diagnosis (PGD) is an established alternative to pre-natal diagnosis, and involves selecting pre-implantation embryos from a cohort generated by assisted reproduction technology (ART). This selection may be required because of familial monogenic disease (e.g. cystic fibrosis), or because one partner carries a chromosome rearrangement (e.g. a two-way reciprocal translocation). PGD is available for couples who have had previous affected children, and/or in the case of chromosome rearrangements, recurrent miscarriages, or infertility. Oocytes aspirated following ovarian stimulation are fertilized by in vitro immersion in semen (IVF) or by intracytoplasmic injection of an individual spermatozoon (ICSI). Pre-implantation cleavage-stage embryos are biopsied, usually by the removal of a single cell on day 3 post-fertilization, and the biopsied cell is tested to establish the genetic status of the embryo. Fluorescence in situ hybridization (FISH) on the fixed nuclei of biopsied cells with target-specific DNA probes is the technique of choice to detect chromosome imbalance associated with chromosome rearrangements, and to select female embryos in families with X-linked disease for which there is no mutation-specific test. FISH has also been used to screen embryos for spontaneous chromosome aneuploidy (also known as PGS or PGD-AS) in order to try and improve the efficiency of assisted reproduction; however, the predictive value of this test using the spreading and FISH technique described here is likely to be unacceptably low in most people's hands and it is not recommended for routine clinical use. We describe the selection of suitable probes for single-cell FISH, spreading techniques for blastomere nuclei, and in situ hybridization and signal scoring, applied to PGD in a clinical setting.

This article describes the selection of suitable probes for single-cell FISH, spreading techniques for blastomere nuclei, and in situ hybridization and signal scoring, applied to pre-implantation genetic diagnosis (PGD) in a clinical setting.

Pre-implantation genetic diagnosis (PGD) is an established alternative to pre-natal diagnosis, and involves selecting pre-implantation embryos from a ...

A Research Method For Detecting Transient Myocardial Ischemia In Patients With Suspected Acute Coronary Syndrome Using Continuous ST-segment Analysis

Each year, an estimated 785,000 Americans will have a new coronary attack, or acute coronary syndrome (ACS). The pathophysiology of ACS involves rupture of an atherosclerotic plaque; hence, treatment is aimed at plaque stabilization in order to prevent cellular death. However, there is considerable debate among clinicians, about which treatment pathway is best: early invasive using percutaneous coronary intervention (PCI/stent) when indicated or a conservative approach (i.e., medication only with PCI/stent if recurrent symptoms occur).
There are three types of ACS: ST elevation myocardial infarction (STEMI), non-ST elevation MI (NSTEMI), and unstable angina (UA). Among the three types, NSTEMI/UA is nearly four times as common as STEMI. Treatment decisions for NSTEMI/UA are based largely on symptoms and resting or exercise electrocardiograms (ECG). However, because of the dynamic and unpredictable nature of the atherosclerotic plaque, these methods often under detect myocardial ischemia because symptoms are unreliable, and/or continuous ECG monitoring was not utilized.
Continuous 12-lead ECG monitoring, which is both inexpensive and non-invasive, can identify transient episodes of myocardial ischemia, a precursor to MI, even when asymptomatic. However, continuous 12-lead ECG monitoring is not usual hospital practice; rather, only two leads are typically monitored. Information obtained with 12-lead ECG monitoring might provide useful information for deciding the best ACS treatment.
Purpose. Therefore, using 12-lead ECG monitoring, the COMPARE Study (electroCardiographic evaluatiOn of ischeMia comParing invAsive to phaRmacological trEatment) was designed to assess the frequency and clinical consequences of transient myocardial ischemia, in patients with NSTEMI/UA treated with either early invasive PCI/stent or those managed conservatively (medications or PCI/stent following recurrent symptoms). The purpose of this manuscript is to describe the methodology used in the COMPARE Study.
Method. Permission to proceed with this study was obtained from the Institutional Review Board of the hospital and the university. Research nurses identify hospitalized patients from the emergency department and telemetry unit with suspected ACS. Once consented, a 12-lead ECG Holter monitor is applied, and remains in place during the patient's entire hospital stay. Patients are also maintained on the routine bedside ECG monitoring system per hospital protocol. Off-line ECG analysis is done using sophisticated software and careful human oversight.

Continuous 12-lead electrocardiographic (ECG) monitoring can identify transient myocardial ischemia, even when asymptomatic, among patients with suspected acute coronary syndrome (ACS). In this article we describe our method for initiating patient monitoring using a Holter device, downloading the ECG data for off-line analysis, and how to utilize the ECG software to identify transient ischemia.

Each year, an estimated 785,000 Americans will have a new coronary attack, or acute coronary syndrome (ACS). The pathophysiology of ACS involves rupture ...

Permanent Ligation of the Left Anterior Descending Coronary Artery in Mice: A Model of Post-myocardial Infarction Remodelling and Heart Failure

Heart failure is a syndrome in which the heart fails to pump blood at a rate commensurate with cellular oxygen requirements at rest or during stress. It is characterized by fluid retention, shortness of breath, and fatigue, in particular on exertion. Heart failure is a growing public health problem, the leading cause of hospitalization, and a major cause of mortality. Ischemic heart disease is the main cause of heart failure.
Ventricular remodelling refers to changes in structure, size, and shape of the left ventricle. This architectural remodelling of the left ventricle is induced by injury (e.g., myocardial infarction), by pressure overload (e.g., systemic arterial hypertension or aortic stenosis), or by volume overload. Since ventricular remodelling affects wall stress, it has a profound impact on cardiac function and on the development of heart failure. A model of permanent ligation of the left anterior descending coronary artery in mice is used to investigate ventricular remodelling and cardiac function post-myocardial infarction. This model is fundamentally different in terms of objectives and pathophysiological relevance compared to the model of transient ligation of the left anterior descending coronary artery. In this latter model of ischemia/reperfusion injury, the initial extent of the infarct may be modulated by factors that affect myocardial salvage following reperfusion. In contrast, the infarct area at 24 hr after permanent ligation of the left anterior descending coronary artery is fixed. Cardiac function in this model will be affected by 1) the process of infarct expansion, infarct healing, and scar formation; and 2) the concomitant development of left ventricular dilatation, cardiac hypertrophy, and ventricular remodelling.
Besides the model of permanent ligation of the left anterior descending coronary artery, the technique of invasive hemodynamic measurements in mice is presented in detail.

Heart failure is the leading cause of hospitalization and a major cause of mortality. A model of permanent ligation of the left anterior descending coronary artery in mice is applied to investigate ventricular remodelling and cardiac dysfunction post-myocardial infarction. The technique of invasive hemodynamic measurements in mice is presented.

Heart failure is a syndrome in which the heart fails to pump blood at a rate commensurate with cellular oxygen requirements at rest or during stress. It ...

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 ...

Evaluation of Coronary Flow Reserve After Myocardial Ischemia Reperfusion in Rats

Coronary artery disease is the leading cause of death worldwide. After an acute myocardial infarction, early and successful myocardial intervention via recanalization of the coronary artery is the most effective strategy for reducing the size of ischemic myocardium. The coronary microvasculature cannot be visualized and imaged&#160;in vivo, but there are several invasive and noninvasive techniques that can be used to assess parameters which depend directly on coronary microvascular function. The endothelial function after ischemia reperfusion can be assessed also at the level of the coronary circulation via the coronary flow reserve (CFR).&#160;In this study, peak velocity of left anterior descending (LAD) coronary arteries was measured in rats in vivo via Transthoracic Doppler Echocardiography during resting and stress challenge (induced by Dobutamine). A normal heart can increase its coronary blood flow up to four times above the resting values during stress induction. Following ischemia reperfusion, we found a significantly diminished CFR, which can be used as a marker of coronary microvascular dysfunction. CFR has opened a window on the importance of microvascular dysfunction and has been shown to predict cardiovascular risk independent of whether the severe obstructive disease is present.

Coronary flow reserve (CFR), is defined as the ratio of maximal coronary blood flow to the resting coronary blood flow. We present a protocol for evaluating CFR in rats via ultrasound, which offers the opportunity to predict cardiovascular risk factors in the absence of obstructive coronary disease.

Coronary artery disease is the leading cause of death worldwide. After an acute myocardial infarction, early and successful myocardial intervention via ...

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 ...

Postconditioning with Lactate-enriched Blood for Cardioprotection in ST-segment Elevation Myocardial Infarction

The beneficial effects of reperfusion therapy for ST-segment elevation myocardial infarction (STEMI) is attenuated by reperfusion injury. No approach has been proven successful in preventing this injury in the clinical setting to date. Meanwhile, a novel approach for cardioprotection in patients with STEMI, i.e., postconditioning with lactate-enriched blood (PCLeB), has recently been reported. PCLeB is a modification of the original protocol of postconditioning, aimed at increasing the delay in the recovery from tissue acidosis produced during ischemia. This was sought to achieve controlled reperfusion with tissue oxygenation and minimal lactate washout. In this modified postconditioning protocol, the duration of each brief reperfusion is gradually increased in a stepwise manner from 10 to 60 s. Each brief ischemic period lasts for 60 s. At the end of each brief reperfusion, injection of lactated Ringer&#39;s solution (20&#8211;30 mL) is performed directly into the culprit coronary artery immediately before the balloon inflation and the balloon is quickly inflated at the lesion site, so that the lactate is trapped inside the ischemic myocardium during each brief repetitive ischemic period. After seven cycles of balloon inflation and deflation, full reperfusion is performed. Stenting is performed thereafter, and the percutaneous coronary intervention is completed. Excellent in-hospital and 6 month outcomes in a limited number of patients with STEMI treated using PCLeB have already been reported. This method article provides a detailed description of each step of the PCLeB procedures.

Herein, we present a protocol for postconditioning with lactate-enriched blood, which is a novel approach for cardioprotection. This protocol comprises&#160;intermittent reperfusion and timely coronary injections of lactated Ringer&#39;s solution. This can be applied to ST-segment elevation myocardial infarction patients who undergo primary percutaneous coronary intervention.

The beneficial effects of reperfusion therapy for ST-segment elevation myocardial infarction (STEMI) is attenuated by reperfusion injury. No approach has ...

In Vitro Model of Coronary Angiogenesis

Here, we describe an in vitro culture assay to study coronary angiogenesis. Coronary vessels feed the heart muscle and are of clinical importance. Defects in these vessels represent severe health risks such as in atherosclerosis, which can lead to myocardial infarctions and heart failures in patients. Consequently, coronary artery disease is one of the leading causes of death worldwide. Despite its clinical importance, relatively little progress has been made on how to regenerate damaged coronary arteries. Nevertheless, recent progress has been made in understanding the cellular origin and differentiation pathways of coronary vessel development. The advent of tools and technologies that allow researchers to fluorescently label progenitor cells, follow their fate, and visualize progenies in vivo have been instrumental in understanding coronary vessel development. In vivo studies are valuable, but have limitations in terms of speed, accessibility, and flexibility in experimental design. Alternatively, accurate in vitro models of coronary angiogenesis can circumvent these limitations and allow researchers to interrogate important biological questions with speed and flexibility. The lack of appropriate in vitro model systems may have hindered the progress in understanding the cellular and molecular mechanisms of coronary vessel growth. Here, we describe an in vitro culture system to grow coronary vessels from the sinus venosus (SV) and endocardium (Endo), the two progenitor tissues from which many of the coronary vessels arise. We also confirmed that the cultures accurately recapitulate some of the known in vivo mechanisms. For instance, we show that the angiogenic sprouts in culture from SV downregulate COUP-TFII expression similar to what is observed in vivo. In addition, we show that VEGF-A, a well-known angiogenic factor in vivo, robustly stimulates angiogenesis from both the SV and Endo cultures. Collectively, we have devised an accurate in vitro culture model to study coronary angiogenesis.

In vitro models of coronary angiogenesis can be utilized for the discovery of the cellular and molecular mechanisms of coronary angiogenesis. In vitro explant cultures of sinus venosus and endocardium tissues show robust growth in response to VEGF-A and display a similar pattern of COUP-TFII expression as in vivo.

Here, we describe an in vitro culture assay to study coronary angiogenesis. Coronary vessels feed the heart muscle and are of clinical importance. Defects ...

Post-Myocardial Infarction Heart Failure in Closed-chest Coronary Occlusion/Reperfusion Model in G&#246;ttingen Minipigs and Landrace Pigs

The development of heart failure is the most powerful predictor of long-term mortality in patients surviving acute myocardial infarction (MI). There is an unmet clinical need for prevention and therapy of post-myocardial infarction heart failure (post-MI HF). Clinically relevant pig models of post-MI HF are prerequisites for final proof-of-concept studies before entering into clinical trials in drug and medical device development.
Here we aimed to characterize a closed-chest porcine model of post-MI HF in adult G&#246;ttingen minipigs with long-term follow-up including serial cardiac magnetic resonance imaging (CMRI) and to compare it with the commonly used Landrace pig model.
MI was induced by intraluminal balloon occlusion of the left anterior descending coronary artery for 120 min in G&#246;ttingen minipigs and for 90 min in Landrace pigs, followed by reperfusion. CMRI was performed to assess cardiac morphology and function at baseline in both breeds and at 3 and 6 months in G&#246;ttingen minipigs and at 2 months in Landrace pigs, respectively.
Scar sizes were comparable in the two breeds, but MI resulted in a significant decrease of left ventricular ejection fraction (LVEF) only in G&#246;ttingen minipigs, while Landrace pigs did not show a reduction of LVEF. Right ventricular (RV) ejection fraction increased in both breeds despite the negligible RV scar sizes. In contrast to the significant increase of left ventricular end-diastolic (LVED) mass in Landrace pigs at 2 months, G&#246;ttingen minipigs showed a slight increase in LVED mass only at 6 months.
In summary, this is the first characterization of post-MI HF in G&#246;ttingen minipigs in comparison to Landrace pigs, showing that the G&#246;ttingen minipig model reflects post-MI HF parameters comparable to the human pathology. We conclude that the G&#246;ttingen minipig model is superior to the Landrace pig model to study the development of post-MI HF.

The overall goal of the current study is to present the techniques of induction of myocardial infarction (MI) and post-myocardial infarction heart failure (post-MI HF) in closed-chest, adult G&#246;ttingen minipigs and the characterization of post-MI HF model in G&#246;ttingen minipigs as compared to Landrace pigs.

The development of heart failure is the most powerful predictor of long-term mortality in patients surviving acute myocardial infarction (MI). There is an ...

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 ...