Bu çalışma, Çin Ulusal Doğa Bilimleri Vakfı (81770271; Y, Liao'ya), Çin Ulusal Doğa Bilimleri Vakfı'nın Ortak Fonları (U1908205; Y, Liao'ya) ve Guangzhou Bilimsel Teknoloji Belediye Planlama Projeleri (201804020083; Dr. Liao'ya) hibelerle desteklendi.

Tüm prosedürler, ABD Ulusal Sağlık Enstitüleri tarafından yayınlanan Laboratuvar Hayvanlarının Bakımı ve Kullanımı yönergelerine uygun olarak gerçekleştirildi (NIH Yayını No. 85-23, 1996'da revize edildi). C57BL/6J erkek fareler (8-10 hafta, 20-25 g) Güney Tıp Üniversitesi Hayvan Merkezi tarafından sağlanmıştır.
1. Ameliyat öncesi hazırlık
<ol><li>25 G'lık bir iğnenin ucunu bir iğne tutucu ile kıstırın ve tutucu gibi sert bir nesneyle köreltin.</li>
	<li>İğneden 5-0 emilebilir bir dikiş geçirin ve ardından bir tutucu13ile 90 ° 'ye kavisleyin. NOT: Farklı araştırma amaçlarına göre, araştırmacılar farklı emilim süresine sahip emilebilir çizgiler seçebilirler. Bu protokolde aort kemerini daraltmak için 2 haftalık emilebilir bir dikiş kullandık.</li>
	<li>25 G'lık bir iğneyi daha 120° kavis yapın ve ligasyon adımında ara parça olarak kullanılacak bir tutucu ile ucu yumuşatın. NOT: Vücut ağırlığı (BW) >25 g olan fareler için aralayıcı olarak 25 G'lık bir iğne kullanılmıştır. 19-24 g BW'lık fareler için 26 G iğne kullanın.</li>
	<li>Ameliyat bölgesini% 75 alkolle dezenfekte edin.</li>
	<li>Isıtma yastığı sıcaklığını 37 °C'ye ayarlayın.</li>
	<li>Sterilize cerrahi aletler hazırlayın (1 oftalmik makas, 1 mikro makas, 2 mikrocerrahi dirsek cımbızı, 1 iğne tutucu ve 1 mikro iğne tutucu dahil).</li>
</ol>2. Anestezi ve tıraşın indüksiyonu
<ol><li>Bir fareyi, salin çözeltisinde seyreltilmiş ksilazin (5 mg/kg) ve ketamin (100 mg/kg) karışımının intraperitoneal enjeksiyonu ile uyuşturun (%0,9 NaCl). Negatif pedal çekme refleksi ile tam anesteziyi onaylayın.</li>
	<li>Kesici dişleri bir dikişle sabitleyerek ve uzuvları yapışkan bantlarla sabitleyerek fareyi geriye doğru sabitleyin.</li>
	<li>Boynundaki ve xiphoiddeki saçları çıkarmak için depilatory krem uygulayın. Bölgeyi iyot ve ardından% 75 alkol ile dezenfekte edin.</li>
</ol>3. Cerrahi
<ol><li>Supra-sternal çentik ile göğüs arasındaki orta çizgi pozisyonunda neşterle 10 mm'nin üzerinde bir kesi yapın. Daha sonra cildi ve yüzeysel fasyayı ayırın.</li>
	<li>Kaburgaları sternal açıdan sayarak ilk interkostal boşluğu tanımlayın. Kesiyi ilk interkostal boşlukta ve sternuma mümkün olduğunca yakın bir yerde gerçekleştirin. Bu alanı açmak için dirsek cımbızı ile sertçe nüfuz edin.</li>
	<li>Enine aort kemeri görünene kadar parenchyma ve timus'u hafifçe ayırın. NOT: Pnömotorakstan kaçınmak için parietal plevraya zarar verme.</li>
	<li>Brakiyofalik arter ile sol ortak karotid arter arasındaki aort kemerinin altındaki 5–0 emilebilir sütür mandal iğnesi ilegeçirin 14. Lütfen braşiyofalik arterin, sol ortak şahdamarın ve sol subklaviyen arterin operasyon alanında görünür olduğundan emin olun.</li>
	<li>1.3. adımda hazırlanan aralayıcıyı enine aort üzerine yerleştirin ve 3.4. NOT: Enine aort çıkarılırken zarar vermemek için ara çubuğun ucu körelmelidir.</li>
	<li>Aralayıcıyı hızlı ama nazikçe çıkarın ve ardından dikişin uçlarını kesin.</li>
	<li>5–0 naylon dikiş kullanarak ilk interkostal alanı ve cildi kapatın. Cildi tekrar% 75 alkolle dezenfekte edin.</li>
	<li>Kurtarmayı teşvik etmek için fareyi ısıtma yastığına yerleştirin. Ameliyattan sonraki ilk 3 gün boyunca intraperitoneal olarak buprenorfin (0.1 mg/kg, q12h) enjekte edin.</li>
	<li>Bilinci geri kazandığında fareyi 12 saat açık/karanlık bir döngü odasında kafese geri döndürün.</li>
	<li>Yukarıdaki tüm adımlarla aynı ancak daralma olmadan sham ameliyatı gerçekleştirin (adım 3.5).</li>
	<li>İpek dikiş grubu için yukarıdaki tüm adımlarla aynı olan ancak 1.2.</li>
</ol>4. Başarılı ligasyon ve ölçümlerin ekokardiyografik değerlendirmesi
<ol><li>Ameliyattan sonra (D) 7. günde ekokardiyografik değerlendirmeyi gerçekleştirin.</li>
	<li>İndüksiyon için inhalasyon yoluyla% 3 izofluran ve anestezi derinliğini korumak için% 1.5 ile 0.5-1 L / dk oksijen akış hızı ile fareyi uyuşturun.</li>
	<li>Fareyi platformda 37 °C'de tutulan geriye doğru yerleştirin ve uzuvlarını elektrota bantleyin.</li>
	<li>Göğüs kıllarını tüy dökücü bir kremle çıkarın ve farenin göğsüne ultrasonik bağlantı maddesi uygulayın.</li>
	<li>30 MHz prob ile enine aort daralmasını değerlendirin.<ol>
<li>Platformu en sola eğin. Sondayı dikey konumda tutun ve sağ parasternal çizgi boyunca göğsün üzerine küçümseyin. Ardından, Aort kemeri açıkça görünene kadar B modu altında X eksenini ve Y eksenini manipüle edin.</li>
		<li>Aort kemeri görünümünü elde etmek için daralmayı B modu ile bulun11. Tepe akış hızını ölçmek ve TAC grubu olarak 3.000 mm/s'den fazla hıza sahip fareleri seçmek için Doppler modunu ve darbeli dalgayı kullanın (değerler ön deneylere dayanır).</li>
		<li>Bernoulli denkleminin değiştirilmiş versiyonuna göre basınç gradyanını hesaplayın11: basınç degradesi = 4 x Vmaks.2. NOT: Enine aort daralma modeli için ideal basınç gradyanı 40–80 mmHg11arasında değişmektedir.</li>
		<li>Cine Store ve Frame Store'ı kullanarak verileri ve görüntüleri kaydedin.</li>
	</ol>
</li>
	<li>30 MHz prob ile sol ventrikül (LV) boyutlarını ve sözleşme durumunu değerlendirin.<ol>
<li>Platformu yatay konuma sıfırlayın. Sondayı sol parasternal çizgiye göre saat yönünün tersine 30°'de tutun.</li>
		<li>Kalbin net ve tam uzun eksen görünümünü elde etmek için B modunu kullanın ve X ve Y'yi manipüle edin.</li>
		<li>Gösterge satırını göstermek için M moduna basın. LV hazne boyutunun daha sonra ölçülmesi, kesirli kısaltma ve LV duvar kalınlığı için Cine Store ve Frame Store ile görüntüler elde edin.</li>
	</ol>
</li>
	<li>Tamamlandığında, izofluran inhalasyonunu durdurun ve farenin anesteziden kurtulmasını sağlar. Ardından, hayvanı 12 saat açık / karanlık bir bisiklet odasında kafesine geri döndürün.</li>
	<li>Ameliyattan sonra D14 ve D28'de, kardiyak parametreleri ölçmek için yukarıdaki adımları tekrarlayın ve ardından histolojik çalışmalar için kalbi hasat edin.</li>
</ol>

<ol>
	<li>Murry, C. E., Jennings, R. B., Reimer, K. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preconditioning+with+ischemia:+a+delay+of+lethal+cell+injury+in+ischemic+myocardium.">Preconditioning with ischemia: a delay of lethal cell injury in ischemic myocardium.</a> Circulation. 74 (5), 1124-1136 (1986).</li><li>Ban, 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=Phosphatidylinositol+3-kinase+gamma+is+a+critical+mediator+of+myocardial+ischemic+and+adenosine-mediated+preconditioning.">Phosphatidylinositol 3-kinase gamma is a critical mediator of myocardial ischemic and adenosine-mediated preconditioning.</a> Circulation Research. 103 (6), 643-653 (2008).</li><li>Wu, Z. K., Iivainen, T., Pehkonen, E., Laurikka, J., Tarkka, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ischemic+preconditioning+suppresses+ventricular+tachyarrhythmias+after+myocardial+revascularization.">Ischemic preconditioning suppresses ventricular tachyarrhythmias after myocardial revascularization.</a> Circulation. 106 (24), 3091-3096 (2002).</li><li>Hausenloy, D. J., Yellon, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preconditioning+and+postconditioning:+underlying+mechanisms+and+clinical+application.">Preconditioning and postconditioning: underlying mechanisms and clinical application.</a> Atherosclerosis. 204 (2), 334-341 (2009).</li><li>Heusch, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+basis+of+cardioprotection:+signal+transduction+in+ischemic+pre-,+post-,+and+remote+conditioning.">Molecular basis of cardioprotection: signal transduction in ischemic pre-, post-, and remote conditioning.</a> Circulation Research. 116 (4), 674-699 (2015).</li><li>Lund, O., Emmertsen, K., Dorup, I., Jensen, F. 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A., 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=Segregation+of+atrial-specific+and+inducible+expression+of+an+atrial+natriuretic+factor+transgene+in+an+in+vivo+murine+model+of+cardiac+hypertrophy.">Segregation of atrial-specific and inducible expression of an atrial natriuretic factor transgene in an in vivo murine model of cardiac hypertrophy.</a> Proceedings of the National Academy of Sciiences of the United States of America. 88 (18), 8277-8281 (1991).</li><li>Wei, X., 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=Myocardial+hypertrophic+preconditioning+attenuates+cardiomyocyte+hypertrophy+and+slows+progression+to+heart+failure+through+upregulation+of+S100A8/A9.">Myocardial hypertrophic preconditioning attenuates cardiomyocyte hypertrophy and slows progression to heart failure through upregulation of S100A8/A9.</a> Circulation. 131 (17), 1506-1517 (2015).</li><li>Huang, J., 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=Ultrasound+biomicroscopy+validation+of+a+murine+model+of+cardiac+hypertrophic+preconditioning:+comparison+with+a+hemodynamic+assessment.">Ultrasound biomicroscopy validation of a murine model of cardiac hypertrophic preconditioning: comparison with a hemodynamic assessment.</a> American Journal of Physiology. Heart and Circulatory Physiology. 313 (1), 138-148 (2017).</li><li>Oka, T., 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=Cardiac-specific+deletion+of+Gata4+reveals+its+requirement+for+hypertrophy,+compensation,+and+myocyte+viability.">Cardiac-specific deletion of Gata4 reveals its requirement for hypertrophy, compensation, and myocyte viability.</a> Circulation Research. 98 (6), 837-845 (2006).</li><li>Li, L., 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=Assessment+of+cardiac+morphological+and+functional+changes+in+mouse+model+of+transverse+aortic+constriction+by+echocardiographic+imaging.">Assessment of cardiac morphological and functional changes in mouse model of transverse aortic constriction by echocardiographic imaging.</a> Journal of Visualized Experiments. (112), e54101 (2016).</li><li>Veldhuizen, R. A., Slutsky, A. S., Joseph, M., McCaig, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+mechanical+ventilation+of+isolated+mouse+lungs+on+surfactant+and+inflammatory+cytokines.">Effects of mechanical ventilation of isolated mouse lungs on surfactant and inflammatory cytokines.</a> The European Respiratory Journal. 17 (3), 488-494 (2001).</li><li>Wang, Q., 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=Induction+of+right+ventricular+failure+by+pulmonary+artery+constriction+and+evaluation+of+right+ventricular+function+in+mice.">Induction of right ventricular failure by pulmonary artery constriction and evaluation of right ventricular function in mice.</a> Journal of Visualized Experiments. 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Yazarların açıklayacak bir şeyi yok.

Kardiyak non-iskemik önkoşulda hala çok az keşfedilmiş bir alan var. Önceki çalışmalarımıza dayanarak, miyokard hipertrofik önkoşul modelini geliştirmek için emilebilir dikişler kullanmaya geçtik.
Önceki raporlarda, birçok araştırmacı aort kemeri 8,14,15'idaraltmak için ipek dikiş kullandı. İpek dikiş kolayca mevcuttu ve genellikle cerrahi yara dikişi, doku ligasyonu ve dok...

İskemik önkoşul, kısa ölümcül olmayan iskemi ve kalbe reperfüzyon ataklarına neden olan ve miyokard yaralanmasını önemli ölçüde azaltma kapasitesine sahip bir fenomendir1. Miyokard enfarktüs boyutu2'yi sınırlamak ve miyokard revaskülarizasyon3'densonra ventrikül tachyarritmilerini bastırmak gibi iskemik önkoşulların bariz klinik etkileri göz önüne alındığında, ön koşul4,5tarafından indüklenen kardiyo koruyucu etkilerin altında kalan mekanizmaları incelerken birçok araştırma yapıldı. Buna karşılık, diğer iskemik olmayan önkoşul türleri nispeten az ilgi gördü. Aort kapağı replasmanı uygulanan aort darlığı olan hastalarda kardiyak hipertrofi köreltilebilir6. Patolojik miyokard hipertrofisinin durumu nerede varsa, ön koşul ilkesi nadiren bildirilmektedir.
1991 yılında, Rockman ve arkadaşları ilk olarak enine aort daralması (TAC)7ile sol ventrikül hipertrofisinin bir fare modelini kurdular. TAC'yi farelerde iki kez çalıştırarak, miyokard hipertrofik önkoşullamanın (MHP) kalpte geçici hipertrofik stimülasyona yol açtığını ve böylece kalbi gelecekte sürekli hipertrofik strese karşı daha dirençli hale getirdiğini kanıtladık8. MHP modelinin özellikleri ultrason biyomikroskop ve hemodinamik değerlendirme ile doğrulanmıştır9. Modelin inşasında önemli noktalar torakotomiyi üç kez, TAC'yi bir hafta, bir hafta boyunca debanding ve 6 hafta boyunca ikincil TAC yapmaktı. Bununla birlikte, debanding kanamaya neden olabilir, bu da acemiler tarafından ustalaşmayı ve popüler olmayı zorlaştırır. Ek olarak, fareleri entübe etmek de teknik bir zorluktur. Yanlış entübasyon farelerde trakeal yaralanmaya, pnömotoraksa ve hatta ölüme neden olabilir. Dolayısı MHP modelini oluştururken bazı prosedürleri geliştirmek gerekli ve değerlidir.
Modelin zorlığını azaltmak ve başarısını artırmak için, ilk TAC için emilebilir dikişlere geçtik ve ekokardiyografi10altında aort daralması boyunca basınç gradyanını ölçerek modelin başarısını izledik. Ön deneylerimize dayanarak, çok düşük basınç gradyanı olan farelerde yeterli miyokard hipertrofisini teşvik etmek zor olurken, çok yüksek basınç gradyanı olan fareler akut kalp yetmezliği geliştirir ve hatta ölür. Model için ideal basınç gradyanı 40–80 mmHg11arasında değişmektedir. Ek olarak, bu deney, ventilatörle ilişkili teknik manipülasyon ve yaralanmayı etkili bir şekilde önleyebilecek bir ventilatöre dayanmadı12.

<table>
	<tbody>
		<tr>
			<td>Absorbable suture (5-0)</td>
			<td>Shandong Kang Lida Medical Products Co., Ltd</td>
			<td>5-0</td>
			<td>Ligation</td>
		</tr>
		<tr>
			<td>Animal ultrasound system VEVO2100</td>
			<td>Visual Sonic</td>
			<td>VEVO2100</td>
			<td>Echocardiography</td>
		</tr>
		<tr>
			<td>Cold light illuminator</td>
			<td>Olympus</td>
			<td>ILD-2</td>
			<td>Light</td>
		</tr>
		<tr>
			<td>Heat pad- thermostatic surgical system (ALC-HTP-S1)</td>
			<td>SHANGHAI ALCOTT BIOTECH CO</td>
			<td>ALC-HTP-S1</td>
			<td>Heating</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>RWD life science</td>
			<td>R510-22</td>
			<td>Inhalant anaesthesia</td>
		</tr>
		<tr>
			<td>Matrx VIP 3000 Isofurane Vaporizer</td>
			<td>Midmark Corporation</td>
			<td>VIP 3000</td>
			<td>Anesthetization</td>
		</tr>
		<tr>
			<td>Medical nylon suture (5-0)</td>
			<td>Ningbo Medical Needle Co.</td>
			<td>5-0</td>
			<td>Close the skin</td>
		</tr>
		<tr>
			<td>Pentobarbital sodium salt</td>
			<td>Merck</td>
			<td>25MG</td>
			<td>Anesthetization</td>
		</tr>
		<tr>
			<td>Precision electronic balance</td>
			<td>Denver Instrument</td>
			<td>TB-114</td>
			<td>Weighing sensor</td>
		</tr>
		<tr>
			<td>Self-made spacer</td>
			<td></td>
			<td></td>
			<td>25-gauge needle</td>
		</tr>
		<tr>
			<td>Silk suture (5-0)</td>
			<td>Yangzhou Yuankang Medical Devices Co., Ltd.</td>
			<td>5-0</td>
			<td>Ligation</td>
		</tr>
		<tr>
			<td>Small animal microsurgery equipment</td>
			<td>Napox</td>
			<td>MA-65</td>
			<td>Surgical instruments</td>
		</tr>
		<tr>
			<td>Transmission Gel</td>
			<td>Guang Gong pai</td>
			<td>250ML</td>
			<td>Echocardiography</td>
		</tr>
		<tr>
			<td>Veet hair removal cream</td>
			<td>Reckitt Benchiser</td>
			<td>RQ/B 33 Type 2</td>
			<td>Remove hair of mice</td>
		</tr>
		<tr>
			<td>Vertical automatic electrothermal pressure steam sterilizer</td>
			<td>Hefei Huatai Medical Equipment Co.</td>
			<td>LX-B50L</td>
			<td>Auto clean the surgical instruments</td>
		</tr>
	</tbody>
</table>

operating transverse aortic constriction with absorbable suture to obtain transient myocardial hypertrophy

Farelerde iki kez enine aort daralmalarına (TUSAŞ) dayanarak, miyokard hipertrofik önkoşullarının (MHP) kardiyomiyosit hipertrofisini hafifletebileceği ve kalp yetmezliğine ilerlemeyi yavaşlatabileceği kanıtlanmıştır. Ancak acemiler için, ventilatör operasyonundaki teknik engeller, göğsün tekrar tekrar açılması ve debandingden kaynaklanan kanamalar nedeniyle MHP modelinin kurulması genellikle oldukça zordur. Bu modeli kolaylaştırmak, cerrahi başarı oranını artırmak ve kanama sıklığını azaltmak için ventilatörsüz bir teknikle ilk TAC tarama için emilebilir dikişlere geçtik. 2 haftalık emilebilir bir dikiş kullanarak, bu prosedürün 2 haftada önemli miyokard hipertrofisine neden olabileceğini gösterdik; ve ameliyattan 4 hafta sonra miyokard hipertrofisi taban çizgisine neredeyse tamamen geriledi. Bu protokolü kullanarak, operatörler daha düşük bir operasyon ölümlülüğü ile MHP modeline kolayca hakim olabilir.

Bu çalışmada, 45 fareyi rastgele üç gruba ayırdık: sham, ipek dikiş grubu ve emilebilir dikiş grubu (TAC'den sonra D0 (taban çizgisi), D14 ve D28'deki her grubun sayısı sırasıyla 15, 10 ve 5 idi). Ameliyattan sonra D7, D14, D21 ve D28'de, daralmış tepe hızı ekokardiyografi ile belirlendi. Aort kemerini daraltmak için emilebilir bir dikiş kullanılmış olsa bile TAC'den sonraki ikinci haftada daralmadaki kan akışı hızının hala 3.000 mm/sn'den fazla olduğunu gördük (Şekil...

Watch this Scientific Journal Video about Operating Transverse Aortic Constriction with Absorbable Suture to Obtain Transient Myocardial Hypertrophy at JoVE.com

Operating Transverse Aortic Constriction with Absorbable Suture to Obtain Transient Myocardial Hypertrophy

Bu protokol, basınç aşırı yükünü giderdikten sonra sol ventrikül hipertrofisi düşüşünü simüle ederek emilebilir dikişli geçici miyokard hipertrofisi elde etmek için geliştirilmiş bir yöntem sunar. Miyokard hipertrofik önkoşul çalışmaları için değerli olabilir.

Geçici Miyokard Hipertrofisi Elde Etmek için Emilebilir Dikiş ile Enine Aort Daralmasını Çalıştırma

Based on twice transverse aortic constrictions (TACs) in mice, it is proved that myocardial hypertrophic preconditioning (MHP) could attenuate ...

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Research

JoVE Journal

Medicine

6.2K Görüntüleme.  Southern Medical University. Bu protokol, basınç aşırı yükünü giderdikten sonra sol ventrikül hipertrofisi düşüşünü simüle ederek emilebilir dikişli geçici miyokard hipertrofisi elde etmek için geliştirilmiş bir yöntem sunar. Miyokard hipertrofik önkoşul çalışmaları için değerli olabilir.

Video: Operating Transverse Aortic Constriction with Absorbable Suture to Obtain Transient Myocardial Hypertrophy

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.

Sürekli ST segment analizi kullanarak Şüpheli Akut Koroner Sendromlu Hastalarda Geçici Miyokard İskemi Teşhisi İçin Bir Araştırma Yöntemi

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

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Ascending Aortic Constriction in Rats for Creation of Pressure Overload Cardiac Hypertrophy Model

Ascending aortic constriction is the most common and successful surgical model for creating pressure overload induced cardiac hypertrophy and heart failure. Here, we describe a detailed surgical procedure for creating pressure overload and cardiac hypertrophy in rats by constriction of the ascending aorta using a small metallic clip. After anesthesia, the trachea is intubated by inserting a cannula through a half way incision made between two cartilage rings of trachea. Then a skin incision is made at the level of the second intercostal space on the left chest wall and muscle layers are cleared to locate the ascending portion of aorta. The ascending aorta is constricted to 50&#8211;60% of its original diameter by application of a small sized titanium clip. Following aortic constriction, the second and third ribs are approximated with prolene sutures. The tracheal cannula is removed once spontaneous breathing was re-established. The animal is allowed to recover on the heating pad by gradually lowering anesthesia. The intensity of pressure overload created by constriction of the ascending aorta is determined by recording the pressure gradient using trans-thoracic two dimensional Doppler-echocardiography. Overall this protocol is useful to study the remodeling events and contractile properties of the heart during the gradual onset and progression from compensated cardiac hypertrophy to heart failure stage.

We describe a stepwise procedure for creating pressure overload and left ventricular hypertrophy in Wistar rats by constriction of the ascending aorta using a small metallic clip. This model is extensively used for studying remodeling changes during cardiac hypertrophy and for identifying and evaluating strategies for regression of such changes.

Basınç Aşırı Kardiyak hipertrofi Modeli Oluşturma Ratlarda Aort daralma, Artan

Ascending aortic constriction is the most common and successful surgical model for creating pressure overload induced cardiac hypertrophy and heart ...

Murine Isolated Heart Model of Myocardial Stunning Associated with Cardioplegic Arrest

The following protocol is of use to evaluate impaired cardiac function or myocardial stunning following moderate ischemic insults. The technique is useful for modeling ischemic injury associated with numerous clinically relevant phenomenon including cardiac surgery with cardioplegic arrest and cardiopulmonary bypass, off-pump CABG, transplant, angina, brief ischemia, etc. The protocol presents a general method to model hypothermic hyperkalemic cardioplegic arrest and reperfusion in rodent hearts focusing on measurement of myocardial contractile function. In brief, a mouse heart is perfused in langendorff mode, instrumented with an intraventricular balloon, and baseline cardiac functional parameters are recorded. Following stabilization, the heart is then subject to brief infusion of a cardioprotective hypothermic cardioplegia solution to initiate diastolic arrest. Cardioplegia is delivered intermittently over 2 hr. The heart is then reperfused and warmed to normothermic temperatures and recovery of myocardial function is monitored. Use of this protocol results in reliable depressed cardiac contractile function free from gross myocardial tissue damage in rodents.

The goal of this protocol to assess myocardial stunning following ischemic cardioplegic arrest in rodents.

Kardiyoplejik Tutuklanma ile Miyokard Çarpıcı İlişkili sıçan İzole Kalp Modeli

The following protocol is of use to evaluate impaired cardiac function or myocardial stunning following moderate ischemic insults. The technique is useful ...

Assessment of Cardiac Morphological and Functional Changes in Mouse Model of Transverse Aortic Constriction by Echocardiographic Imaging

Transverse aortic constriction (TAC) in mice has been used as a valuable model to study mechanisms of cardiac hypertrophy and heart failure1. A reliable noninvasive method is essential to assess real-time cardiac morphological and functional changes in animal models of heart disease. Transthoracic echocardiography represents an important tool for noninvasive assessment of cardiac structure and function2. Here we used a high-resolution ultrasound imaging system to monitor myocardial remodeling and heart failure progression over time in a mouse model of TAC. B-mode, M-mode, and Doppler imaging were used to precisely assess cardiac hypertrophy, ventricular dilatation, and functional deterioration in mice following TAC. Color and pulse wave (PW) Doppler imaging was used to noninvasively measure pressure gradient across the aortic constriction created by TAC and to assess transmitral blood flow in mice. Thus transthoracic echocardiographic imaging provides comprehensive noninvasive measurements of cardiac dimensions and function in mouse models of heart disease.

The goal of this protocol is to noninvasively assess cardiac structural and functional changes in a mouse model of heart disease created by transverse aortic constriction, using B- and M-mode echocardiography and color/pulse wave Doppler imaging.

Ekokardiyografik Imaging tarafından Enine Aort Konstrüksiyon Mouse Modeli Kardiyak Morfolojik Değerlendirilmesi ve Fonksiyonel Değişiklikler

Transverse aortic constriction (TAC) in mice has been used as a valuable model to study mechanisms of cardiac hypertrophy and heart failure1. A reliable ...

Minimally Invasive Transverse Aortic Constriction in Mice

Minimally invasive transverse aortic constriction (MTAC) is a more desirable method for the constriction of the transverse aorta in mice than standard open-chest transverse aortic constriction (TAC). Although transverse aortic constriction is a highly functional method for the induction of high pressure in the left ventricle, it is a more difficult and lengthy procedure due to its use of artificial ventilation with tracheal intubation. TAC is oftentimes also less survivable, as the newer method, MTAC, neither requires the cutting of the ribs and intercostal muscles nor tracheal intubation with a ventilation setup. In MTAC, as opposed to a thoracotomy to access to the chest cavity, the aortic arch is reached through a midline incision in the anterior neck. The thyroid is pulled back to reveal the sternal notch. The sternum is subsequently cut down to the second rib level, and the aortic arch is reached simply by separating the connective tissues and thymus. From there, a suture can be wrapped around the arch and tied with a spacer, and then the sternal cut and skin can be closed. MTAC is a much faster and less invasive way to induce left ventricular hypertension and enables the possibility for high-throughput studies. The success of the constriction can be verified using high-frequency trans-thoracic echocardiography, particularly color Doppler and pulsed-wave Doppler, to determine the flow velocities of the aortic arch and left and right carotid arteries, the dimension of the blood vessels, and the left ventricular function and morphology. A successful constriction will also trigger significant histopathological changes, such as cardiac muscle cell hypertrophy with interstitial and perivascular fibrosis. Here, the procedure of MTAC is described, demonstrating how the resulting flow changes in the carotid arteries can be examined with echocardiography, gross morphology, and histopathological changes in the heart.

Minimally invasive transverse aortic constriction (MTAC) conserves the essentials of regular transverse aortic constriction (TAC) while eliminating the use of a ventilator with tracheal intubation. It proves to be a highly desirable method for high-throughput studies on left ventricular overload, particularly in translational studies.

Farelerde Minimal İnvaziv Enine Aort Konstrüksiyon

Minimally invasive transverse aortic constriction (MTAC) is a more desirable method for the constriction of the transverse aorta in mice than standard ...

Full-root Aortic Valve Replacement by Stentless Aortic Xenografts in Patients with Small Aortic Roots

In patients with small aortic roots who need an aortic valve replacement with biological valve substitutes, the implantation of the stented pericardial valve might not meet the functional needs. The implantation of a too-small stented pericardial valve, leading to an effective orifice area indexed to a body surface area less than 0.85 cm2/m2, is regarded as prosthesis-patient mismatch (PPM). A PPM negatively affects the regression of left ventricular hypertrophy and thus the normalization of left ventricular function and the alleviation of symptoms. Persistent left ventricular hypertrophy is associated with an increased risk of arrhythmias and sudden cardiac death. In the case of predictable PPM, there are three options: 1) accept the PPM resulting from the implantation of a stented pericardial valve when comorbidities of the patient forbid the more technically demanding operative technique of implanting a larger prosthesis, 2) enlarge the aortic root to accommodate a larger stented valve substitute, or 3) implant a stentless biological valve or a homograft. Compared to classical aortic valve replacement with stented pericardial valves, the full-root implantation of stentless aortic xenografts offers the possibility of implanting a 3-4 mm larger valve in a given patient, thus allowing significant reduction in transvalvular gradients. However, a number of cardiac surgeons are reluctant to transform a classical aortic valve replacement with stented pericardial valves into the more technically challenging full-root implantation of stentless aortic xenografts. Given the potential hemodynamic advantages of stentless aortic xenografts, we have adopted full-root implantation to avoid PPM in patients with small aortic roots necessitating an aortic valve replacement. Here, we describe in detail a technique for the full-root implantation of stentless aortic xenografts, with emphasis on the management of the proximal suture line and coronary anastomoses. Limitations of this technique and alternative options are discussed.

Full-root aortic valve replacement by stentless aortic xenograft is a viable option in patients with small aortic roots. We describe, a technique for the full-root implantation of stentless aortic xenografts, with emphasis on the management of the proximal suture line and coronary anastomoses, and discuss its limitations and alternative options.

Küçük Aort Köklü Hastalarda Stentless Aortik Xenograftlarla Tam Kök Aort Kapak Replasmanı

In patients with small aortic roots who need an aortic valve replacement with biological valve substitutes, the implantation of the stented pericardial ...

Technique of Minimally Invasive Transverse Aortic Constriction in Mice for Induction of Left Ventricular Hypertrophy

Transverse aortic constriction (TAC) in mice is one of the most commonly used surgical techniques for experimental investigation of pressure overload-induced left ventricular hypertrophy (LVH) and its progression to heart failure. In the majority of the reported investigations, this procedure is performed with intubation and ventilation of the animal which renders it demanding and time-consuming and adds to the surgical burden to the animal. The aim of this protocol is to describe a simplified technique of minimally invasive TAC without intubation and ventilation of mice. Critical steps of the technique are emphasized in order to achieve low mortality and high efficiency in inducing LVH.
Male C57BL/6 mice (10-week-old, 25-30 g, n=60) were anesthetized with a single intraperitoneal injection of a mixture of ketamine and xylazine. In a spontaneously breathing animal following a 3-4 mm upper partial sternotomy, a segment of 6/0 silk suture threaded through the eye of a ligation aid was passed under the aortic arch and tied over a blunted 27-gauge needle. Sham-operated animals underwent the same surgical preparation but without aortic constriction. The efficacy of the procedure in inducing LVH is attested by a significant increase in the heart/body weight ratio. This ratio is obtained at days 3, 7, 14 and 28 after surgery (n = 6 - 10 in each group and each time point). Using our technique, LVH is observed in TAC compared to sham animals from day 7 through day 28. Operative and late (over 28 days) mortalities are both very low at 1.7%.
In conclusion, our cost-effective technique of minimally invasive TAC in mice carries very low operative and post-operative mortalities and is highly efficient in inducing LVH. It simplifies the operative procedure and reduces the strain put on the animal. It can be easily performed by following the critical steps described in this protocol.

The aim of this protocol is to describe step-by-step the technique of minimally invasive transverse aortic constriction (TAC) in mice. By elimination of intubation and ventilation which are mandatory for the commonly used standard procedure, minimally invasive TAC simplifies the operative procedure and reduces the strain put on the animal.

Minimal invaziv transvers aort daralma farelerde sol ventrikül hipertrofisi indüksiyon için tekniği

Transverse aortic constriction (TAC) in mice is one of the most commonly used surgical techniques for experimental investigation of pressure ...

A Closed-chest Model to Induce Transverse Aortic Constriction in Mice

Research on cardiac hypertrophy and heart failure is frequently based on pressure overload mouse models induced by TAC. The standard procedure is to perform a partial thoracotomy to visualize the transverse aortic arch. However, the surgical trauma caused by the thoracotomy in open-chest models changes the respiratory physiology as the ribs are dissected and left unattached after chest closure. To prevent this, we established a minimally invasive, closed chest approach via lateral thoracotomy. Herein we approach the aortic arch via the 2nd intercostal space without entering the chest cavities, leaving the mouse with a less traumatic injury to recover from. We perform this operation using standard laboratory settings for open chest TAC procedures with equal survival rates. Apart from maintaining physiological breathing patterns due to the closed chest approach, the mice seem to benefit by showing rapid recovery, as the less invasive technique appears to facilitate a fast healing process and to reduce immune response after trauma.

Here, we present a protocol of Transverse Aortic constriction (TAC) via a lateral thoracotomy. This technique is a minimally invasive, closed chest surgical procedure aiming to simulate pressure overload and heart failure in mice utilizing standard TAC laboratory settings.

Transvers aort daralma farelerde ikna etmek için kapalı-göğüs manken

Research on cardiac hypertrophy and heart failure is frequently based on pressure overload mouse models induced by TAC. The standard procedure is to ...

Murine Cervical Aortic Transplantation Model using a Modified Non-Suture Cuff Technique

With the introduction of powerful immunosuppressive protocols, distinct advances are possible in the prevention and therapy of acute rejection episodes. However, only minor improvement in the long-term results of transplanted solid organs could be observed over the past decades. In this context, chronic allograft vasculopathy (CAV) still represents the leading cause of late organ failure in cardiac, renal and pulmonary transplantation.
Thus far, the underlying pathogenesis of CAV development remains unclear, explaining why effective treatment strategies are presently missing and emphasizing a need for relevant experimental models in order to study the underlying pathophysiology leading to CAV formation. The following protocol describes a murine heterotopic cervical aortic transplantation model using a modified non-suture cuff technique. In this technique, a segment of the thoracic aorta is interpositioned in the right common carotid artery. With the use of the non-suture cuff technique, an easy to learn and reproducible model can be established, minimizing the possible heterogeneity of sutured vascular micro anastomoses.

Here, we present a protocol of heterotopic aortic transplantation in mice using the non-suture cuff technique in a cervical murine model. This model can be used to study the underlying pathology of chronic allograft vasculopathy (CAV) and can help evaluate new therapeutic agents in order to prevent its formation.

Modifiye Dikişsiz Manşet Tekniği Kullanılarak Murine Servikal Aort Transplantasyon Modeli

With the introduction of powerful immunosuppressive protocols, distinct advances are possible in the prevention and therapy of acute rejection episodes. ...

Using Q Suture to Enhance Resistance to Gap Formation and Tensile Strength of Repaired Flexor Tendons

Peripheral epitendinous sutures are believed to enhance core suture strength in tendon repair and decrease the risk of gapping between tendon ends. Here Q suture, an alternative to peripheral sutures, is presented for the use in tendon repair. Its effects on gap formation and tensile strength of the repaired tendons were compared with conventional running peripheral sutures. Three 2-strand sutures and three 4-strand sutures were used in repairing porcine tendons. The time required for performing 2Q and running sutures were recorded. The repaired tendons were subjected to a cyclic loading test, and the cycle number, during which a 2-mm gap was formed, was determined. After the cyclic loading, the gap size at the tendon ends and the ultimate strength of the repaired tendons were measured. Augmentation with the Q sutures reduced the number of tendons showing 2-mm gaps at tendon ends during cyclic loading. With addition of Q sutures 2-strand sutures significantly increased the ultimate strength of the repaired tendons and 4-strand sutures decreased the gap distance at the repair site of tendons. The time required for performing 2Q sutures was significantly less than that for running sutures. Therefore, we conclude that the Q suture is efficient in enhancing the tensile resistance and tendon repair strength and can be an alternative to conventional peripheral sutures.

Here, we present a &#8220;Q&#8221; suture technique that can be performed in tendon repair and its effects on the gap formation and tensile strength of the repaired tendons. Q suture is shown to be efficient in enhancing the tensile resistance and tendon repair strength.

Boyanır Fleksör Tendonun Boşluk Oluşumuna ve Çekme Mukavemetine Karşı Direnci artırmak için Q Sütür kullanma

Peripheral epitendinous sutures are believed to enhance core suture strength in tendon repair and decrease the risk of gapping between tendon ends. Here Q ...