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| {{SI}}
| | #Redirect [[Coronary artery calcification#Treatment]] |
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| {{CMG}}; '''Associate Editors-In-Chief:''' Thomas Tu, M.D.; Brian C. Bigelow, M.D.
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| ==Overview==
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| Calcified lesions pose several challenges to the interventional cardiologists as they are sometimes difficult to cross with the angioplasty equipment, they are less likely to fully dilate, they are prone to recoil, and they often do not allow for full expansion of the stent. Failure to fully expand the stent may result in restenosis. [[Rotational atherectomy]] is frequently employed following unsuccessful pre-dilating [[PTCA]] to perform plaque modification. [[Stents]] should be deployed only after ensuring that the lesion can be fully expanded by a conventional balloon angioplasty.
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| ==Diagnosis of Lesion Calcification==
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| The coronary angiogram is fairly insensitive to the presence of lesion calcification, particularly the presence of deep vessel wall calcification. [[Intravascular ultrasound]] is much more sensitive sensitive in the assessment of vessel wall calcification. Conventional coronary [[angiography]] has limited [[sensitivity]] for the detection of smaller amounts of [[calcium]], and has moderate [[sensitivity]] for the detection of extensive lesion [[calcium]] (sensitivity 60% and 85% for three- and four-quadrant calcium, respectively). <ref name="pmid7895353">{{cite journal |author=Mintz GS, Popma JJ, Pichard AD, ''et al.'' |title=Patterns of calcification in coronary artery disease. A statistical analysis of intravascular ultrasound and coronary angiography in 1155 lesions |journal=Circulation |volume=91 |issue=7 |pages=1959–65 |year=1995 |month=April |pmid=7895353 |doi= |url=}}</ref> Calcification of [[SVG|SVGs]] is generally within the reference [[vessel wall]] rather than within the lesion itself. Calcification is often associated with older graft age, [[insulin–dependent diabetics]], and [[smoking]]. <ref name="pmid15723972">{{cite journal |author=Castagna MT, Mintz GS, Ohlmann P, ''et al.'' |title=Incidence, location, magnitude, and clinical correlates of [[saphenous vein graft]] [[calcification]]: an intravascular [[ultrasound]] and [[angiographic]] study |journal=Circulation |volume=111 |issue=9 |pages=1148–52 |year=2005 |month=March |pmid=15723972 |doi=10.1161/01.CIR.0000157160.69812.55 |url=}}</ref>
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| ==Complications and Technical Challenges Associated with Calcified Lesions ==
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| * Heavily calcified lesions add complexity to a [[percutaneous coronary intervention]].
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| * The presence of coronary [[calcification]] reduces the compliance of the vessel, and it may predispose calcified plaque–normal wall interfaces to [[dissections]] after [[balloon angioplasty]].
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| * The presence of coronary [[calcification]] also reduces the ability to cross chronic total [[occlusion|occlusions]]. In severely calcified lesions, stent strut expansion is inversely correlated with the circumferential arc of calcium. <ref name="pmid11170322">{{cite journal |author=Vavuranakis M, Toutouzas K, Stefanadis C, Chrisohou C, Markou D, Toutouzas P |title=Stent deployment in calcified lesions: can we overcome calcific restraint with high-pressure balloon inflations? |journal=Catheter Cardiovasc Interv |volume=52 |issue=2 |pages=164–72 |year=2001 |month=February |pmid=11170322 |doi= |url=}}</ref>
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| * The presence of extensive coronary [[calcification]] poses unique challenges for PCI as [[calcium]] in the vessel wall leads to irregular and inflexible [[Lumen (anatomy)|lumens]]. It also makes the delivery of guidewires, [[balloons]], and [[stents]] much more challenging.
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| * Extensive coronary [[calcification]] also renders the [[vessel]] wall rigid, necessitating higher [[balloon]] inflation pressures to obtain complete stent expansion, and occasionally leading to “undilatable” lesions that resist any achievable [[balloon]] expansion pressure.
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| == Treatment ==
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| There are a variety of diagnostic and treatment options for calcified lesions. Better early outcomes may be achieved by using a multi-device interventional strategy.
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| ===Percutaneous Transluminal Coronary Angioplasty (PTCA)===
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| [[PTCA]] is an invasive [[Cardiology|cardiologic]] therapeutic procedure to treat the [[stenosis|stenotic]] (narrowed) [[coronary artery|coronary arteries]] of the [[heart]]. The term [[balloon angioplasty]] is commonly used to describe this procedure, which describes the inflation of a [[balloon]] within the [[coronary artery]] to crush the plaque into the walls of the artery.
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| In the treatment of calcified lesions with PTCA, certain considerations must be made. For one, [[Interventional cardiologist|interventional cardiologists]] should consider using [[hydrophilic]] guidewires, as heavy [[calcification]] may make wire advancement difficult. Also, calcified [[plaque|plaques]] usually require higher [[balloon]] pressures to fully expand than normal [[plaque|plaques]]. Because of this, [[Compliance|non-compliant]] [[balloons]] may be a better choice than [[Compliance|compliant]] or [[Compliance|semi-compliant]] [[balloons]]. Differential expansion of compliant or semi-compliant [[balloons]] inside a particular [[lesion]] may jeopardize less diseased segments if the [[balloon]] expands greater than the vessel's native diameter. On the contrary, non-compliant [[balloons]] allow for a more uniform expansion at high pressures and therefore may be a better choice to apply focused pressure at the calcified [[plaque]]. Another option is to place a second "buddy" wire adjacent to the [[balloon]] to improve the ability to dilate calcified [[plaque]].
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| If pre-dilatation fails to fully expand a calcified [[stenosis]], then the risks and benefits of stent deployment should be carefully considered due to the risk of incomplete expansion and future [[restenosis]].
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| ===Intravascular Ultrasound (IVUS)===
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| [[IVUS]] is a [[medical imaging]] methodology that uses a specially designed [[catheter]] with a miniaturized [[ultrasound]] probe attached to the distal end of the [[catheter]]. The proximal end of the [[catheter]] is attached to computerized [[ultrasound]] equipment. It allows the application of [[ultrasound]] technology to see from inside [[blood vessel|blood vessels]] out through the surrounding [[blood]] column, visualizing the [[endothelium]] (inner wall) of [[blood vessel|blood vessels]] in living individuals. IVUS is used in the coronary arteries to determine the amount of [[atheroma|atheromatous plaque]] built up at any particular point in the epicardial coronary artery.
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| While coronary angiography by [[fluroscopy]] is limited in its detection and severity assessment of coronary calcification, IVUS can assess the extent of calcification and may be particularly useful for instances when the reason for poor [[balloon]] expansion is uncertain. Although this approach has its advantages over angiography, heavy involvement of superficial, sub-endothelial [[calcification]] may require [[rotational atherectomy]].
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| ===Cutting Balloon and FX MiniRailTM===
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| A [[cutting balloon]] is an [[angioplasty]] device used in [[PCI|percutaneous coronary interventions]]. It has a special [[balloon]] tip with small blades, that are activated when the [[balloon]] is inflated. This procedure is different from [[rotational atherectomy]], in which a diamond tipped device spins at high revolutions to cut away calcific (chalky) [[atheroma]] usually prior to coronary [[stenting]].
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| This technique can be useful in treating calcified lesions because the microsurgical blades on the surface of the [[balloon]] may help to score and modify calcified [[plaques]]. Generally, if a [[cutting balloon]] will cross the lesion, a [[stent]] can be delivered. Although this technique has its advantages, there are certain additional considerations that must be made before deciding to use this procedure. For one, despite their usefulness, these [[balloons]] are often more difficult to deliver past tortuous or calcified segments, so extra care must be used. Also, there were no significant differences observed in rates of [[restenosis]] when using this procedure.
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| ===Rotational Atherectomy===
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| [[Rotational atherectomy]] is a minimally invasive method of removing [[plaque]] and blockages from an [[artery]] and subsequently widening arteries that have been narrowed by arterial disease. Unlike [[angioplasty]] and [[stents]] of blocked arteries that simply push blockages aside into the wall of the artery, rotational atherectomy involves inserting a thin catheter with a rotating blade on its end into the artery. The rotating edge is used to remove [[plaque]] buildups, thereby opening the [[artery]] and restoring normal blood flow.
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| [[Rotational atherectomy]] is frequently employed following unsuccessful pre-dilating [[PTCA]] to perform [[plaque]] modification. This procedure facilitates [[Percutaneous transluminal coronary angioplasty|PTCA]] by creating micro-fractures, removing calcified plaque, and increasing vessel compliance. Despite its usefulness in treating calcified lesions, certain precautions should be taken. In an effort to limit the risk of vessel [[laceration]], smaller diameter [[Burr (cutter)|burrs]] are now preferred. A general guideline to use is that the initial [[Burr (cutter)|burr]] to [[Lumen (anatomy)|luminal]] ratio should be 1:2. Additional caution should be taken when a coronary [[dissection]] is present, as [[rotational atherectomy]] may propagate the [[dissection]].
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| * '''Rotational atherectomy in severe lesion calcification:''' [[Rotational atherectomy]] is the preferred pretreatment method in patients with severe lesion [[calcification]], particularly ostial lesions, and facilitates the delivery and expansion of coronary [[stents]] by creating microdissection planes within the fibrocalcific [[plaque]]. Yet even with these contemporary methods, the presence of moderate or severe coronary calcification is associated with reduced procedural success and higher complication rates<ref name="pmid12127606">{{cite journal |author=Wilensky RL, Selzer F, Johnston J, ''et al.'' |title=Relation of percutaneous coronary intervention of complex lesions to clinical outcomes (from the NHLBI Dynamic Registry) |journal=Am. J. Cardiol. |volume=90 |issue=3 |pages=216–21 |year=2002 |month=August |pmid=12127606 |doi= |url=}}</ref>, including stent dislodgement.
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| * '''Rotational atherectomy in mild-moderate calcifications:''' In less severely calcified lesions, no differences in [[restenosis]] rates were found after paclitaxel-eluting stent implantation in calcified and non-calcified vessels. <ref name="pmid16253590">{{cite journal |author=Moussa I, Ellis SG, Jones M, ''et al.'' |title=Impact of coronary culprit lesion calcium in patients undergoing paclitaxel-eluting stent implantation (a TAXUS-IV sub study) |journal=Am. J. Cardiol. |volume=96 |issue=9 |pages=1242–7 |year=2005 |month=November |pmid=16253590 |doi=10.1016/j.amjcard.2005.06.064 |url=}}</ref>
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| ===Directional Coronary Atherectomy (DCA)===
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| DCA involves inserting a thin, flexible [[catheter]] with a small blade on its end into the artery, which cuts off [[plaque]] buildups. These [[plaque]] shavings are caught with the catheter and are subsequently removed from the artery.<ref>http://www.lvhn.org/lvh/Your_LVH/Health_Care_Services/Heart_Care_MIMS/Most_Advanced_Treatments|3487</ref>
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| One problem that may arise during the procedure is that heavy [[calcification]] proximal to the target lesion may limit deliverability of the device and its success.
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| ===Excimer Laser Coronary Atherectomy/Angioplasty (ECLA)===
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| ECLA uses a laser, instead of a traditional blade, to perform [[atherectomy]] and [[angioplasty]]. The excimer laser is a pulsed [[ultraviolet]] laser that can erode calcified [[plaque]] while also causing minimal thermal tissue injury.<ref name="pmid1860207">{{cite journal |author=Cook SL, Eigler NL, Shefer A, Goldenberg T, Forrester JS, Litvack F |title=Percutaneous excimer laser coronary angioplasty of lesions not ideal for balloon angioplasty |journal=Circulation |volume=84 |issue=2 |pages=632–43 |year=1991 |month=August |pmid=1860207 |doi= |url=}}</ref>
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| One advantage of using ELCA is that it fractures calcified [[plaques]], thereby facilitating [[PTCA]]. However, it also has a higher equipment cost and has a lesser ease of use than [[rotational atherectomy]]. Furthermore, it is more commonly used in lower extremity [[peripheral arterial disease]] than in [[CAD|coronary artery disease (CAD)]].
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| ===Stents===
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| In [[cardiology]], a [[stent]] is a tube that is inserted into an artery to counteract significant decreases in vessel diameter by acutely propping it open.
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| In the treatment of calcified [[lesions]], [[stents]] are frequently used in conjunction with [[PTCA]] or [[atherectomy]] to decrease the risk of [[restenosis]]. Extra care should be taken in deploying stents in lesions where incomplete expansion occurs following pre-dilation, as incomplete expansion of a target lesion will increase the likelihood of [[restenosis]]. [[Stents]] should be deployed only after ensuring full [[balloon]] expansion.
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| ==References==
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| {{Reflist|2}}
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| [[Category:Cardiology]]
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| [[Category: Up-To-Date]]
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| [[Category: Up-To-Date Cardiology]]
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