The Coronaries
Theo Kofidis in Minimally Invasive Cardiac Surgery, 2021
Cardiac surgery has made many giant leaps of advancements since the first CPB machine was designed and used in 1953 by John Gibbons. The birth of coronary artery bypass graft surgery (CABG) took root when Alexis Carrel first described operating on the coronary circulation in 1910. Being the first surgeon to appreciate the relationship between angina and stenotic coronary artery disease, he performed “complementary circulation” for diseased native coronary arteries in canine experiments. Since then, CABG underwent three distinct eras in its evolution – the “experimental” pioneering era and the era of “vein grafting” followed by the era of “mixed grafting – arterial and venous”. These all fall within the era of conventional median sternotomy. Today, we have moved into the fourth era, perhaps even more advanced, where the field of minimally invasive coronary revascularization presents a viable and attractive option, or even the default modality in today’s age of hybrid coronary revascularization, further enhancing the partnership between cardiac surgeons and interventional cardiologists to bring about optimal patient outcomes.
Endothelial Damage
Giuseppe Mancia, Guido Grassi, Konstantinos P. Tsioufis, Anna F. Dominiczak, Enrico Agabiti Rosei in Manual of Hypertension of the European Society of Hypertension, 2019
The measurement of coronary blood flow by Doppler flow wires enables assessment of endothelial function in the coronary microcirculation by quantitative angiography during the intracoronary infusion of various endothelium-dependent (acetylcholine and substance P) or -independent (sodium nitroprusside and nitroglycerin) vasodilators (104). The concomitant intracoronary infusion of NG-mono-methyl-l-arginine (L-NMMA, a potent inhibitor of the eNOS) also provides the opportunity to establish the proportion of the vasomotor response due to the activity of the eNOS and thus the NO availability (105). Although this test directly assesses coronary circulation, its invasive nature limits its use to patients with advanced disease and precludes repeated testing during serial follow-up. While other, noninvasive techniques are available to assess endothelial function of the coronary microvasculature (including positron emission tomography, myocardial perfusion imaging and echocardiography) (104), the radiation exposure, the reduced availability of the machines used for their assessment, the questionable reproducibility and the need for systemic administration of endothelial agonists and antagonists limit their use in clinical practice. Nevertheless, it was shown that endothelial function in coronary microcirculation has prognostic value in patients with established coronary disease (100).
C
Anton Sebastian in A Dictionary of the History of Medicine, 2018
Coronary Artery Disease A description of coronary circulation was given by Raymond de Vieussens (1641–1715) of France in Traite du Coeur in 1715, and calcification of the coronary arteries was described by Giovanni Battista Morgagni (1682–1771) in 1761. Allan Burns (1731–1813), a Scottish surgeon and cardiologist, made the first suggestion that angina was due to coronary artery obstruction in his Observations of Some of the Most Important and Frequent Diseases of the Heart, published in 18 09. The first case of correctly diagnosed coronary artery occlusion in life was reported by Adam Hammer (1818–1878) in 1876. George Dock of Pennsylvania diagnosed a case and later confirmed it at autopsy in 1896. Timothy Leary of America made a microscopic study of coronary artery lesions in 1934 and came to the important conclusion that the pathogenesis of the atherosclerotic lesions was related to disturbance of lipid metabolism. Around the same time Frederick Arthur Willius (1888–1972) at the Mayo Clinic commenced extensive studies on lipids and demonstrated that high total lipid and cholesterol levels positively correlated with coronary artery disease. The modern theory of atherosclerosis was initiated in 1946 by J.B. Duguid, who proposed that the atheromatous plaques were essentially mural thrombi that had become incorporated into the vessel wall. The stage of platelet deposition in atherogenesis was studied by L.A. Harker and colleagues in 1981. This led to the use of antiplatelet agents. See angina pectoris, coronary artery bypass graft.
Angiography derived assessment of the coronary microcirculation: is it ready for prime time?
Published in Expert Review of Cardiovascular Therapy, 2022
Jinying Zhou, Yoshinobu Onuma, Scot Garg, Nozomi Kotoku, Shigetaka Kageyama, Shinichiro Masuda, Kai Ninomiya, Yunlong Huo, Johan H.C. Reiber, Shengxian Tu, Jan J. Piek, Javier Escaned, Divaka Perera, Christos Bourantas, Hongbing Yan, Patrick W. Serruys
Coronary artery disease (CAD) has long been recognized as a disease of the major epicardial vessels affecting the conductance of the coronary circulation, however, whilst this is amenable to mechanical revascularization, this ignores coronary microvascular dysfunction which is the actual cause of angina and ischemia in up to two-thirds of patients [1,2]. Of note, if only noninvasive ischemia testing is used in patients with symptoms and documented non-obstructive coronary arteries, a median of 30% of patients with the underlying microvascular disease will remain undiagnosed [2]. Epicardial coronary arteries contribute to minimal resistance to coronary flow (5–10%), whilst microcirculation constitutes the remaining 95%. Being essentially a “black hole’ for angiographers (Figure 1(a,b)), microvasculature remains challenging in terms of physiological assessment. Following technical advances in intra-coronary pressure and flow measurements, quantitative functional assessment of the coronary microcirculation has become feasible using methods such as combined pressure-velocity loops [3], the thermodilution-derived pressure wire-based index of microvascular resistance (IMR) [4] and Doppler pressure wire-based hyperemic microvascular resistance (HMR) [5]. However, these techniques have not been widely incorporated into routine practice due to technical challenges, procedural costs, increased procedure time, and the intolerance some patients have to hyperemia.
Pathophysiology and mechanisms of Acute Coronary Syndromes: atherothrombosis, immune-inflammation, and beyond
Published in Expert Review of Cardiovascular Therapy, 2022
Giovanni Cimmino, Luigi Di Serafino, Plinio Cirillo
In about 10% of patients with ACS, myocardial ischemia is not due to atherothrombosis. In these cases, a functional alteration of coronary circulation involving both large epicardial coronary arteries or the coronary microcirculation have been indicated as responsible of the acute event [6]. The main role of the coronary circulation is to provide the cardiac muscle with the oxygen it requires by regulating the coronary blood flow. In fact, myocardial oxygen extraction is almost maximal at rest, thereby an increase in oxygen demand would result in a corresponding increase in coronary blood flow. Coronary microvascular disease (CMD) refers to the dysfunction of this mechanism leading to myocardial ischemia and it is characterized by the presence of some abnormalities in the ‘function’ and ‘structure’ of the coronary microcirculation due to endothelial and SMCs dysfunction. Most of the patients with CMD do not present ‘significant’ atherosclerotic obstructive coronary disease at coronary angiography despite presenting with typical chest pain.
Angina due to coronary artery spasm (variant angina): diagnosis and intervention strategies
Published in Expert Review of Cardiovascular Therapy, 2021
Thanh Ha Nguyen, Gao-Jing Ong, Olivia C Girolamo, Viviane De Menezes Caceres’, Armin Muminovic, Yuliy Y Chirkov, John D Horowitz
Coronary angiography with or without provocative testing represents the ‘gold standard’ for the definitive diagnosis of CAS. Provocative testing is not necessary if CSFP is present, since this in itself provides a diagnosis, and is rarely performed if any high-grade fixed stenosis is present. In the context of clinical suspicion of a diagnosis of CAS, all ‘fixed’ stenoses should be subjected to intracoronary injections of NTG [51]. The main indication for provocative testing, therefore, is apparently normal coronary circulation in a patient with a high probability of CAS. The two most widely used agents remain ergonovine and ACh. Ergonovine is a potent vasoconstrictor via α-adrenoceptor and 5-HT2 receptor activation, and can be given either intravenously [52], or intra-coronary [53] during invasive coronary angiography to induce CAS. ACh is administered at increasing doses directly into the left or right coronary arteries [54]. It is also important to note that administration of ACh can lead to transient atrioventricular block or bradycardia, and therefore necessitates empirical placement of a temporary pacing wire in the right ventricle for the duration of the provocative test.
Related Knowledge Centers
- Myocardial Infarction
- Vein
- Hypoxia
- Oxygen Saturation
- Artery
- Cardiac Muscle
- Brain
- Coronary Arteries
- Altered Level of Consciousness
- Coronary Ischemia