[[Coronary artery]] [[lumen|luminal]] [[stenosis|narrowing]] reduces the flow reserve for oxygenated blood to the heart, typically producing intermittent [[Angina pectoris|angina]] if very advanced; [[lumen|luminal]] occlusion usually produces a [[myocardial infarction|heart attack]]. However, it has been increasingly recognized, since the late 1980s, that coronary catheterization does not allow the recognition of the presence or absence of coronary [[atherosclerosis]] itself, only significant [[lumen|luminal]] changes which have occurred as a result of end stage complications of the [[atherosclerosis|atherosclerotic]] process. See [[IVUS]] and [[atheroma]] for a better understanding of this issue.
[[Coronary artery]] [[lumen|luminal]] [[stenosis|narrowing]] reduces the flow reserve for oxygenated blood to the heart, typically producing intermittent [[Angina pectoris|angina]] if very advanced; [[lumen|luminal]] occlusion usually produces a [[myocardial infarction|heart attack]]. However, it has been increasingly recognized, since the late 1980s, that coronary catheterization does not allow the recognition of the presence or absence of coronary [[atherosclerosis]] itself, only significant [[lumen|luminal]] changes which have occurred as a result of end stage complications of the [[atherosclerosis|atherosclerotic]] process. See [[IVUS]] and [[atheroma]] for a better understanding of this issue.
== Essentials of Optimal Coronary Angiographic Projections ==
It is very important that the injection of contrast is delayed until fluoroscopy commences in order to identify calcification or staining of contrast. The acquisition should continue until the contrast has cleared from the arterial tree. Slightly longer acquisition times are needed for evaluation of TIMI Frame Count and TIMI Myocardial Perfusion Grade before and after treatment in percutaneous coronary interventions. Also, an important determinant of the length of injection is the need to visualise collaterals for occluded vessels.
==[[Suggested Angiographic Projections]]==
==[[Congenital Anomalies of the Coronary Circulation]]==
==Therapeutic procedures==
By changing the diagnostic [[catheter]] to a guiding [[catheter]], physicians can also pass a variety of instruments through the [[catheter]] and into the [[artery]] to a [[lesion]] site. The most commonly used are 0.014 inch diameter guide wires and the balloon dilation [[catheter]]s, see [[angioplasty]].
By injecting [[radiocontrast]] agent through a tiny passage extending down the [[balloon catheter]] and into the balloon, the balloon is progressively expanded. The hydraulic pressures are chosen and applied by the physician, according to how the [[balloon]] within the [[stenosis]] responds. The [[radiocontrast]] filled [[balloon]] is watched under fluoroscopy (it typically assumes a "dog bone" shape imposed on the outside of the balloon by the [[stenosis]] as the balloon is expanded), as it opens. As much hydraulic brute force is applied as judged needed and visualized to be effective to make the [[stenosis]] of the [[artery]] [[lumen]] visibly enlarge.
Typical normal [[coronary artery]] pressures are in the <200 mmHg range (27 kPa). The hydraulic pressures applied within the balloon may extend to as high as 19000 mmHg (2,500 kPa). Prevention of over-enlargement is achieved by choosing balloons manufactured out of high tensile strength clear plastic membranes. The balloon is initially folded around the catheter, near the tip, to create a small cross-sectional profile to facilitate passage though [[lumen|luminal]] stenotic areas and designed to inflate to a specific pre-designed diameter. If over inflated, the balloon material simply tears and allows the inflating [[radiocontrast]] agent to simply escape into the blood.
Additionally, several other devices can be advanced into the artery via a guiding [[catheter]]. These include laser [[catheter]]s, [[stent]] [[catheter]]s, [[IVUS]] [[catheter]]s, Doppler [[catheter]], pressure or temperature measurement [[catheter]] and various [[clot]] and grinding or removal devices. Most of these devices have turned out to be niche devices, only useful in a small percentage of situations or for research.
[[Stent]]s, which are specially manufactured expandable stainless steel mesh tubes, mounted on a balloon [[catheter]], are the most commonly used device beyond the balloon [[catheter]]. When the [[stent]]/balloon device positioned within the [[stenosis]], the balloon is inflated which, in turn, expands the [[stent]] and the artery. The balloon is removed and the [[stent]] remains in place, supporting the inner [[artery]] walls in the more open, dilated position. Current stents generally cost around $1,000 to 3,000 each U.S. 2004 dollars, the drug coated ones being the more expensive.
==Advances in catheter based physical treatments ==
Interventional procedures have been plagued by restenosis due to the formation of [[endothelium|endothelial]] [[biological tissue|tissue]] overgrowth at the lesion site. [[Restenosis]] is the body's response to the injury of the vessel wall from [[angioplasty]] and to the [[stent]] as a [[foreign body]]. As assessed in clinical trials during the late 1980 and 1990s, using only balloon angioplasty (POBA, plain old balloon angioplasty), up to 50% of patients suffered significant restenosis but that percentage has dropped to the single to lower two digit range with the introduction of drug-eluting stents. Sirolimus and paclitaxel are the two drugs used in coatings which are currently FDA approved in the United States. As opposed to bare metal, drug eluting stents are covered with a medicine that is slowly dispersed with the goal of suppressing the restenosis reaction.
The key to the success of drug coating has been;
* choosing effective agents,
* developing ways of adequately binding the drugs to the stainless surface of the [[stent]] struts (the coating must stay bound despite marked handling and stent deformation stresses) and
* developing coating controlled release mechanisms that release the drug slowly over about 30 days.
Image:Postmortem angiogram of coronary arteries 1.jpg|Myocardial Infarction: Postmortem angiogram of coronary arteries
Image:Postmortem angiogram of coronary arteries 2.jpg|Angiogram: X-ray, horizontal sections of ventricle showing penetrating artery distribution (a quite good example)
Image:Postmortem angiogram of coronary arteries 3.jpg|Angiogram: X-ray, postmortem coronary arteries with multiple lesions
Image:Postmortem angiogram of coronary arteries 4.jpg|Angiogram: X-ray postmortem normal coronaries
Image:Postmortem angiogram of coronary arteries 5.jpg|Angiogram: Postmortem angiogram with apparent lesions in proximal right coronary artery
Image:Postmortem angiogram of coronary arteries 6.jpg|Angiogram: X-ray, postmortem injection horizontal slice of left ventricle showing very well penetrating arteries
Image:Postmortem angiogram of coronary arteries 7.jpg|Angiogram Saphenous Vein Bypass Graft: X-ray shows rather close-up large vein anastomosing to much smaller artery
Image:Postmortem angiogram of coronary arteries 8.jpg|Angiogram Saphenous Vein Bypass Graft: X-ray postmortem injection showing vein anastomosis very well and the vasculature of the right and left ventricles
Image:Postmortem angiogram of coronary arteries 9.jpg|Coronary artery: Atherosclerosis: X-ray postmortem extensive lesions in this x-ray of whole heart
Image:Postmortem angiogram of coronary arteries 10.jpg|X-Ray Intramyocardial Arteries: X-ray three horizontal slices of ventricles showing quite well the penetrating arteries
Image:Postmortem angiogram of coronary arteries 11.jpg|X-Ray Intramyocardial Arteries: X-ray three horizontal slices of ventricles showing quite well the penetrating arteries
Image:Postmortem angiogram of coronary arteries 12.jpg|Coronary Artery Anomalous Origin; Left From Pulmonary Artery: Angiogram, postmortem, after switch of left coronary artery to aorta
Image:Postmortem angiogram of coronary arteries 14.jpg|Coronary artery: Atherosclerosis: X-ray, postmortem, dissected arteries and extensive lesions
Image:Postmortem angiogram of coronary arteries 15.jpg|Coronary artery: Atherosclerosis: X-ray, postmortem, close-up view of artery with extensive lesions (very good example)
Image:Postmortem angiogram of coronary arteries 16.jpg|Coronary artery: Atherosclerosis: X-ray, postmortem, dissected artery, lesions in small branches
Coronary arteryluminalnarrowing reduces the flow reserve for oxygenated blood to the heart, typically producing intermittent angina if very advanced; luminal occlusion usually produces a heart attack. However, it has been increasingly recognized, since the late 1980s, that coronary catheterization does not allow the recognition of the presence or absence of coronary atherosclerosis itself, only significant luminal changes which have occurred as a result of end stage complications of the atherosclerotic process. See IVUS and atheroma for a better understanding of this issue.
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↑Proudfit WL, Shirey EK, Sones FM Jr. Selective cine coronary arteriography. Correlation with clinical findings in 1,000 patients. Circulation 1966;33:901-10. PMID 5942973.
↑Sones FM, Shirey EK. Cine coronary arteriography. Mod Concepts Cardiovasc Dis 1962;31:735-8. PMID 13915182.
↑Smith SC Jr, Feldman TE, Hirshfeld JW Jr, Jacobs AK, Kern MJ, King SB 3rd, Morrison DA, O'neill WW, Schaff HV, Whitlow PL, Williams DO, Antman EM, Smith SC Jr, Adams CD, Anderson JL, Faxon DP, Fuster V, Halperin JL, Hiratzka LF, Hunt SA, Jacobs AK, Nishimura R, Ornato JP, Page RL, Riegel B; American College of Cardiology/American Heart Association Task Force on Practice Guidelines; ACC/AHA/SCAI Writing Committee to Update the 2001 Guidelines for Percutaneous Coronary Intervention. ACC/AHA/SCAI 2005 Guideline Update for Percutaneous Coronary Intervention-Summary Article: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/SCAI Writing Committee to Update the 2001 Guidelines for Percutaneous Coronary Intervention). J Am Coll Cardiol. 2006 Jan 3;47(1):216-35. PMID 16386696
