Chapter 5 Diagnostic Coronary Angiography · 2009. 6. 12. · descending coronary artery arises...

CORONARY ANATOMY AND ANOMALIES

The right coronary artery (RCA) arises fromthe right coronary sinus and runs in the right AVgroove (Fig. 5-1). Generally, the conus arteryand the sinoatrial artery arise from the RCA. Inapproximately 85% of individuals, the posteriordescending coronary artery arises from theRCA (defined as a right dominant coronary cir-culation). The left main coronary artery arisesfrom the left coronary sinus. Within a few cen-timeters of its origin, it divides into the left ante-rior descending (LAD) coronary artery (in theanterior interventricular groove), the left cir-cumflex coronary artery (in the atrioventriculargroove) and, in a minority of cases, a ramusintermedius artery.

Coronary artery anomalies are found in 1 to1.5% of individuals (Fig. 5-2); most anomaliesare benign. The most common anomaly is sep-arate origins from the aorta of the LAD and leftcircumflex (i.e., absence of a left main coro-nary artery), which occurs in 0.4 to 1% of indi-viduals and is occasionally associated with abicuspid aortic valve. Clinically significantanomalies include origin of a coronary arteryfrom the opposite coronary sinus (e.g., leftmain artery originating from the right coronarysinus), the presence of a single coronaryostium (and hence a single coronary artery),and origin of a coronary artery from the pul-monary artery.

INTRODUCTION

TECHNIQUESCoronary angiography delineates the course

and size of the coronary arteries, identifies coro-nary anomalies, and provides information onthe location and degree of any obstruction(Table 5-1). Coronary angiography is performedby injecting radiopaque contrast dye directlyinto the ostium of the left and right coronaryarteries. Access to the aorta is usually gained viapercutaneous puncture of the femoral artery;however brachial, radial, and axillary arteriescan also be used for arterial access. Specific pre-formed catheters are passed over a guide wireinto the aortic root; the selection of the catheterto be used depends on the access site and thecoronary artery being investigated. The wire isremoved and the coronary artery is cannulatedwith use of fluoroscopic guidance. Contrast dyeis injected during cineradiography while bloodpressure and ECG are continually monitoredand sequential frames are recorded.

Complete evaluation of coronary arteriesinvolves angiography in multiple projections(Figs. 5-3 and 5-4), necessitated by the difficultyof visualizing three-dimensional structures intwo dimensions. These views are obtained byrotating the imaging system to different posi-tions around the patient who lies supine on aradiolucent table. Views from the left or the rightof the patient can be obtained by varying thedegrees of angle. The imaging system can alsobe rotated from head (cranial) to toe (caudal)

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The ability to directly visualize coronary arteries was a seminal advance in the history of mod-ern medicine and led directly to the development of the concept of transluminal angioplasty (firstperformed by Charles Dotter in 1964), CABG (first performed by Rene Favaloro in 1967), percu-taneous transluminal peripheral angioplasty (first performed by Andreas Gruentzig in 1974), andpercutaneous transluminal coronary angioplasty (first performed by Andreas Gruentzig in 1977).With the high prevalence of coronary heart disease (CHD) in industrialized countries and theadvances made in its treatment, the use of diagnostic coronary angiography has continued toincrease. In 2000, approximately 2,000,000 cardiac catheterizations were performed in the Unit-ed States. This chapter focuses on the coronary anatomy and the technique of coronary angiog-raphy and its clinical use.

George A. Stouffer

Chapter 5

Diagnostic Coronary Angiography

Sinoatrial nodal branch

Atrial branch of rightcoronary artery

Right coronary artery

Anterior cardiac veinsof right ventricle

Small cardiac vein

Interventricular septal branches

Right marginal branch of right coronary artery

Left coronary artery

Left auricle (cut)

Circumflex branch of left coronary artery

Great cardiac (anterior interventricular) vein

Anterior interventricularbranch (left anteriordescending) of leftcoronary artery

Sternocostal surface

Oblique vein of left atrium(Marshall)

Great cardiac (anteriorinterventricular) vein

Circumflex branch ofleft coronary artery

Coronary sinus

Left marginal branch

Posterior leftventricular branch

Interventricular septal branches

Posterior vein ofleft ventricle

Middle cardiac(posteriorinterventricular) vein

Sinoatrial nodal branch

Sinoatrial node

Small cardiac vein


Posterior interventricularbranch (posterior descending)of right coronary artery

Right marginal branch

Diaphragmatic surface

Coronary Arteries and Cardiac Veins

INTRODUCTION

DIAGNOSTIC CORONARY ANGIOGRAPHY

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Figure 5-1

INTRODUCTION


Anterior interventricular (left anterior descending)branch of left coronary artery very short. Apical partof anterior (sternocostal) surface supplied by branchesfrom posterior interventricular (posterior descending)branch of right coronary artery curving around apex.

Posterior interventricular (posterior descending)branch derived from circumflex branch of left coronary artery instead of from right coronaryartery

Posterior interventricular (posterior descending)branch absent. Area supplied chiefly by small branches from circumflex branch of leftcoronary artery and from right coronary artery.

Posterior interventricular (posterior descending)branch absent. Area supplied chiefly by elongatedanterior interventricular (left anterior descending)branch curving around apex.

Coronary Arteries and Cardiac Veins: Variations

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Figure 5-2

Left coronary artery: Left anterior oblique veiw


Circumflex branch

Arteriogram

Anterior interventricular branch (left anterior descending)

Diagonal branches of anterior interventricular branch

Atrioventricular branch of circumflex branch


Posterolateral branches

(Perforating) interventricular septal branches

Left coronary artery: Right anterior oblique view


Circumflex branch

Arteriogram


Anterior interventricularbranch (left anterior descending)

(Perforating) interventricularseptal branches

Posterolateral branches

Diagonal branch ofAnterior interventricular branch

Atrioventricular branch of circumflex branch

Coronary Arteries: Arteriographic Views

Right coronary artery: Left anterior oblique view

Sinoatrial (SA) nodal branch


Arteriogram

Atrioventricular (AV) nodal branch

Branches to back of left ventricle


Posterior interventricular branch(posterior descending artery)

Right coronary artery: Right anterior oblique view

Sinoatrial (SA) nodal branch

Conus (arteriosus) branch

Arteriogram



Atrioventricular (AV) nodal branch

Right posterolateral branches (to backof left ventricle)

Posterior interventricular branch(posterior descending artery)

INTRODUCTION


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Figure 5-3

INTRODUCTION


Angiogram of normal right coronary artery (RCA) and normal posterolateral (PL) and posterior descending (PDA) branches

Angiogram of normal left anterior descending coronary artery (LAD) and left circumflex (LC)artery

Angiographic demonstration of narrowing of RCA

Angiogram demonstrating filling of LAD by dye injected into RCA via collateral vessels

Angiographic catheter

Atherosclerotic narrowing of RCA

RCA

Dye injection of RCA

LAD

Collateral vessels

Occlusion of proximal LAD

RCA

Angiographic catheter

Coronary Angiography

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Figure 5-4

positions. Although there is an almost limitlesscombination of potential imaging positions, sev-eral standard approaches have been developed(as described herein) that allow full visualizationof the coronary arteries in most patients.

In all cases, multiple views help to avoid fore-shortening of specific areas and the potentiallyconfounding feature of overlapping branches,and are obtained using caudal or cranial angula-tion in combination with left and right angulation.The most commonly used views for left coronaryangiography include right anterior oblique (RAO)with cranial and caudal angulation, and left ante-rior oblique (LAO) with cranial and caudal angu-lation. The most commonly used views for RCAangiography include right anterior oblique andleft anterior oblique projections with or withoutcranial angulation. Individual variation in coro-nary anatomy or location of stenoses often neces-sitates customization of projections. Standardnomenclature to define coronary segments hasbeen developed by several groups, including theCoronary Artery Surgery Study investigators andthe Bypass Angioplasty Revascularization Investi-gation investigators.

The usual method of analyzing angiograms inclinical practice identifies areas of relative narrow-ing, and then quantifies the degree of narrowing bycomparing the minimal diameter of the narrowedcoronary segment with that of an adjacent, normal-

INTRODUCTION


appearing reference segment. In many angiogra-phy suites, experienced observers estimate thedegree of stenosis; however, stenosis can be quan-tified using calipers or quantitative computerangiography. Because atherosclerotic plaques areoften eccentric, orthogonal views are needed toaccurately determine the degree of obstruction.

Flow in coronary arteries can be estimated atthe time of coronary angiography with a scaledeveloped by the Thrombolysis in MyocardialInfarction (TIMI) investigators. Flow defined asTIMI 0 indicates a completely occluded artery.TIMI 1 flow describes a severe lesion in which dyepasses the area of narrowing but does not extendto the distal portion of the vessel. With TIMI 2 flow,the distal vessel is opacified but not as rapidly aswould be expected or as rapidly as nonobstructedvessels. TIMI 3 flow is “normal.” The TIMI flowindex has shown significant prognostic value. TIMI“frame counts,” the number of frames necessaryfor dye to reach the distal portion of the vessel, areused as a quantitative index of flow.

Microvascular integrity can be assessed at thetime of coronary angiography with use of angio-graphic myocardial blush scores. These scores,which measure contrast dye density andwashout in the area of interest, correlate with LVfunctional recovery post-MI, and prognosis. Inthe setting of acute MI, myocardial blush scoresadd additional prognostic information to TIMIframe score and persistent ST elevation.

Coronary angiography can be performed sep-arately or as part of cardiac catheterization or aninterventional procedure. Most patients referredfor diagnostic angiography also undergo left-sided heart catheterization and left ventriculog-raphy. Increasingly, these patients also undergoangiography of other vascular beds, as indicated.For example, patients with hypertension com-monly undergo renal angiography; those withclaudication undergo lower extremity arteryangiography; and those with left internal mam-mary artery grafting to the LAD coronary arteryundergo subclavian angiography (Fig. 5-5).

INDICATIONS The most common indication for coronary

angiography is to determine the presence, loca-tion, and severity of atherosclerotic lesions.Coronary angiography provides essential infor-

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Table 5-1Information Provided by SelectiveCoronary Angiography

• Origin of major coronary arteries• Size of coronary arteries• Course of coronary arteries• Branches originating from large and medium

coronary arteries• Degree and location of lumen irregularities• Presence of fistulas• Presence of collaterals• Presence of bridging• Presence of large thrombus• Aneurysms• Spasm and response to nitroglycerin• Coronary plaques—location, degree of narrowing,

eccentricity, involvement of side branches, length

INTRODUCTION


Atherosclerotic obstruction of subclavian artery

Retrograde blood flow from left anterior descending (LAD) coronary artery to subclavian artery via left internal mammary (LIMA) creating “steal” and myocardial ischemia

LIMA

LIMA–LAD anastomosis

Stent placement restores flow to subclavian and via LIMA–LAD anastomosis also restores myocardial perfusion, relieving ischemic symptoms

Obstruction of subclavian artery

StentAntegrade flow

LAD

Poor opacification of artery distal to stenosis and minimal appearance of dye in LIMA

Initial left coronary artery angiography in a patient with prior bypass surgery with complaints of increasing angina. Angiogram demonstrates retrograde flow of dye up LIMA into subclavian artery (arrow).

Stent relieves obstruction and restores normal blood flow

Angiographic Demonstration of Subclavian Steal

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Figure 5-5

Scans reprinted from Circulation 2002;105:184e, doi:10.1161–01.CIR 0000017400.13819.4D.

mation in the diagnosis of CAD, in determiningprognosis, and in decision-making regardingrevascularization. Neither percutaneous coro-nary intervention nor CABG can occur withoutcoronary angiography. More rarely, coronaryangiography is used to diagnose anomalies,muscular bridging, fistula, spasm, emboli,aneurysms, and arteritis.

Indications for coronary angiography in a ran-dom sample of 100 consecutive patients at theUniversity of North Carolina are listed in Table 5-2.The most common indication was for evaluationof symptomatic CAD—either stable angina or

acute coronary syndrome. Less common indica-tions include valvular heart disease; congestiveheart failure; evaluation before heart, lung orliver transplant; periodic evaluation after hearttransplant; and congenital heart disease. Indica-tions for coronary angiography not included onthis list are being a sudden cardiac death sur-vivor, history of ventricular tachycardia, abnor-mal results of stress tests in high-risk occupations(e.g., pilot or bus driver), history of postrevascu-larization ischemia, and being a prospectiveheart transplant donor whose age and risk factorprofile suggest possible CAD.

INTRODUCTION


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Table 5-2Indications for Coronary Angiography

Percent of Patients No. Patients (%)

Exertional Angina 51

Non–Q-wave MI 18

Congestive heart failure 9

Primary treatment of ST-elevation MI 7

Valvular heart disease 6

Cardiogenic shock 2

ST elevation post administration of thrombolytic 1agents (rescue angioplasty)

Miscellaneous 6

Annual evaluation after heart transplantation

Hypertrophic cardiomyopathy with chest pain

Constrictive pericarditis

Congenital heart disease

Preoperative evaluation for proximal aortic and/or aortic arch aneurysm repair

Preoperative assessment for aortic dissection repair

Evaluation prior to heart, lung, or liver transplantation

Ventricular arrhythmias and/or survival of sudden cardiac death

Abnormal stress tests in high-risk occupations (e.g., pilot)

Postrevascularization ischemia

Prospective heart transplant donor whose age and risk factor profile suggests the possibility of coronary artery disease

Patient who is at high risk for coronary disease when other cardiac surgical procedures (e.g., pericardectomy) are planned

The percentages reflect the relative volume at the University of North Carolina based on a random sample of 100 consecutive patients.MI indicates myocardial infarction.

INTRODUCTION


USE OF CORONARYANGIOGRAPHY IN THEEVALUATION OF PATIENTS WITHCHEST PAIN—CLINICAL PRACTICE

The American Heart Association and Ameri-can College of Cardiology publish guidelines onthe indications for coronary angiography(http://circ.ahajournals.org/cgi/content/full/99/17/2345). Use of coronary angiography in spe-cific conditions is assigned a rating (Table 5-3) ofthe weight of evidence that (1) supports the indi-cation (class I and IIa), (2) argues against the indi-cation (class III), or (3) is insufficient to support orrefute the indication (class IIb). Because there arerisks associated with coronary angiography,patients with class III indications should rarely, ifever, undergo the procedure. Referral for angiog-raphy with class II indications is a decision thatinvolves the preferences of the referring physi-cian and the patient; many patients with class IIaindications are referred for angiography, where-as it is less common for patients with class IIbindications to undergo coronary angiography.Despite the guidelines, marked differences existin practice patterns among individual physicians,geographic regions within the United States, anddifferent countries. In some areas, coronaryangiography is considered to be the standard ofcare for particular conditions, whereas noninva-sive approaches are favored elsewhere.

The two most important issues in the evalua-tion of patients with suspected ischemic chestpain are the identification of the extent of CADand the delineation of LV function. This can bedone either directly (e.g., cardiac catheteriza-tion) or indirectly (e.g., exercise treadmill test-ing). If patients have stable, exertional symp-toms, an exercise treadmill test can providediagnostic and prognostic information. In addi-tion to ECG findings, the test provides informa-tion on symptoms during exercise, blood pres-sure response, and duration of exercise.Combining ECG monitoring with either nuclearimaging (to determine myocardial perfusion) orechocardiographic imaging (to determine LVfunction) during exercise enhances the sensitivi-ty and specificity of treadmill testing (see chap-ters 4 and 6). Imaging is essential in patients inwhom the ECG response cannot be interpreted(e.g., left bundle branch block or Wolfe-Parkin-

son-White syndrome). It is also extremely helpfulin situations in which the sensitivity and/or speci-ficity of exercise ECG is reduced, for example, inmiddle-aged females or concomitant with LVhypertrophy. Pharmacologic stress testing cou-pled with imaging is available for patients unableto exercise.

Evidence for flow-limiting CAD on stress test-ing is an indication to proceed to coronaryangiography. Occasionally, further evaluation isnot needed if patient symptoms are controlledby medical therapy and if information from thestress test (e.g., duration of exercise, extent ofischemia) suggests that patient prognosis isgood. Rarely, patients with normal results ofstress tests are referred for coronary angiogra-phy. These are patients with typical symptoms inwhom results of the stress test are thought to befalsely negative.

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Table 5-3Summary of AHA/ACC ClassificationRegarding Appropriateness of Proce-dures

Class Definition

I There is evidence and/or generalagreement that coronary angiography isuseful and effective.

IIa There is conflicting evidence and/or adivergence of opinion about theusefulness/efficacy of performingcoronary angiography, but the weight ofevidence/opinion is in favor ofusefulness/efficacy.

IIb There is conflicting evidence and/or adivergence of opinion about theusefulness/efficacy of performingcoronary angiography, with theusefulness/efficacy of coronaryangiography being less well-establishedby evidence/opinion.

III There is evidence and/or generalagreement that the procedure is notuseful/effective and in some cases maybe harmful.

With permission from J Am Coll Cardiol 1999; 33:1756–1903. Tablecreated using data in text ACC/AHA Guidelines for CoronaryAngiography.

In selected patients with stable symptoms andin all patients with unstable symptoms, cardiaccatheterization is performed without prior stresstesting. Included in this group are patients withsymptoms highly typical of angina, congestiveheart failure, prior MI, and prior revascularizationand/or with symptoms at a low level of exertion(class III or IV). In addition, patients with unstablesymptoms should be referred directly forcatheterization. In particular, patients with unsta-ble angina, recent non–Q-wave MI or acute ST-elevation MI should be referred for urgent oremergent angiography, with possible use of per-cutaneous intervention (see chapter 8).

CONTRAINDICATIONSThe only absolute contraindication to coro-

nary angiography is lack of patient consent.However, relative contraindications reflectgreatly increased associated risks in certain con-ditions. Acute renal failure or severe preexistingrenal dysfunction, especially in diabetic individ-uals, identifies patients at high risk for contrast-induced nephropathy. Severe coagulopathy,active bleeding, or both limit the ability to anti-coagulate the blood of patients for intervention-al procedures and increase the risk of vascularcomplications. Decompensated heart failurecan lead to respiratory failure when the patientis required to remain supine during the proce-dure. Electrolyte abnormalities and/or digitalistoxicity can predispose the patient to malignantarrhythmias during contrast injection. Other rel-ative contraindications include patient inabilityto cooperate, active infection, allergy to contrastagents, uncontrolled hypertension, severeperipheral vascular disease, and pregnancy.

LIMITATIONS Coronary angiography outlines the lumen of

the vessel but is unable to provide any informa-tion on wall thickness. Proper interpretation ofstenosis severity involves identification of anappropriate reference segment with which tocompare the abnormal section. Furthermore,even with the identification of a proper refer-ence section, studies have shown that experi-enced observers are limited in their ability toconsistently identify hemodynamically signifi-cant coronary stenoses.

INTRODUCTION


These limitations have led to the developmentof technologies to supplement coronary angiog-raphy, including intravascular ultrasound andpressure wire analysis. Intravascular ultrasoundprovides two-dimensional cross-sectionalimages in which the three layers of the vessel(intima, media, and adventitia) can frequently beidentified (see chapter 2). Luminal cross-section-al area, wall thickness, and plaque area can beidentified and quantified. Additionally, calcium,thrombus, and dissection planes can be imaged.Intravascular ultrasound is clinically useful in theassessment of complex coronary lesions, leftmain coronary artery lesions, and results ofinterventional procedures.

Advances in technology have enabled pres-sure transducers to be attached to 0.014-inangioplasty wires, allowing determination ofintracoronary pressure distal to coronarystenoses. By comparing distal coronary pressurewith aortic pressure at rest and during condi-tions of maximal coronary hyperemia, fractionalflow reserve can be calculated. Determinationof fractional flow reserve is clinically useful inassessment of intermediate lesions (i.e., coro-nary lesions of unclear significance angiographi-cally) and determination of adequate balloonangioplasty and/or stent placement.

COMPLICATIONSThe risk of major complications during coro-

nary angiography, defined as death, MI, or stroke,is approximately 0.3%. If the definition is expand-ed to include vascular complications, arrhyth-mias, and contrast reactions, the rate is still lessthan 2%. Conditions that increase risk includeshock, acute coronary syndrome, renal failure,left main CAD, severe valvular disease, increasedage, peripheral vascular disease, prior anaphylac-toid reaction to contrast media, and congestiveheart failure. The risks of cardiac catheterizationwith coronary angiography are outlined in Table5-4. Complication rates were remarkably consis-tent across registries from the 1980s. More recentregistries have focused on complications associ-ated with coronary interventions.

FUTURE DIRECTIONSDuring the 40 years that diagnostic cardiac

catheterization has been performed, continual

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INTRODUCTION


modifications of catheters, imaging approaches,and points of access have enabled the proce-dure to be performed more quickly and safely.Many investigators are now examining whethernoninvasive approaches to coronary arteryimaging (based on improvements in MRI or CT)will lessen the need for, or even replace, diag-nostic coronary angiography. Regardless of

whether it is the routine use of noninvasive imag-ing or further modifications of invasive imaging,one can be certain that further reduction in themorbidity and mortality rates associated withdefining coronary anatomy will be achieved.

REFERENCES Alderman EL, Stadius ML. The angiographic definitions of

the Bypass Angioplasty Revascularization Investigation(BARI). Coron Artery Dis 1992;3:1189–1207.

Angelini P, Velasco JA, Flamm S. Coronary anomalies: Inci-dence, pathophysiology, and clinical relevance. Circula-tion 2002;105:2449–2454.

Gibson CM, Cannon CP, Murphy SA, et al. Relationship ofTIMI myocardial perfusion grade to mortality after admin-istration of thrombolytic drugs. Circulation 2000;101:124–130.

Pijls NH, de Bruyne B, Peels K, et al. Measurement of frac-tional flow reserve to assess the functional severity of coro-nary-artery stenoses. N Engl J Med 1996;334:1703–1708.

Poli A, Fetiveau R, Vandoni P, et al. Integrated analysis ofmyocardial blush and ST-segment elevation recovery aftersuccessful primary angioplasty: Real-time grading ofmicrovascular reperfusion and prediction of early and laterecovery of left ventricular function. Circulation2002;106:313–318.

Ringqvist I, Fisher LD, Mock M, et al: Prognostic value ofangiographic indices of coronary artery disease from theCoronary Artery Surgery Study (CASS). J Clin Invest1983;71:1854–1866.

Scanlon PJ, Faxon DP, Audet AM, et al: ACC/AHA guidelinesfor coronary angiography. A report of the American Col-lege of Cardiology/American Heart Association TaskForce on practice guidelines (Committee on CoronaryAngiography). Developed in collaboration with the Soci-ety for Cardiac Angiography and Interventions. J Am CollCardiol 1999;33:1756–1824.

Sheehan FH, Braunwald E, Canner P, et al: The effect of intra-venous thrombolytic therapy on left ventricular function:A report on tissue-type plasminogen activator and strep-tokinase from the Thrombolysis in Myocardial Infarction(TIMI Phase I) trial. Circulation 1987;75:817–829.

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Table 5-4Complications of Coronary Angiography

Year 1982 1989 1990

N 53,581 222,553 59,792

Death, % 0.14 0.10 0.11

MI, % 0.07 0.06 0.05

CVA, % 0.07 0.07 0.07

Arrhythmia, % 0.56 0.47 0.38

Vascular, % 0.57 0.46 0.43

Total, % 1.82 1.74 1.70

Rates of complications of coronary angiography and cardiac cather-ization as reported by registries of the Society for Cardiac Angiogra-phy and Intervention.CVA indicates cerebrovascular accident or stroke; MI, myocardialinfarction.With permission from Kennedy JW. Complications associated withcardiac catheterization and angiography. Cathet Cardiovasc Diagn1982;8:5–11; Johnson LW, Lozner EC, Johnson S, et al. Coronary arte-riography 1984–1987: A report of the Registry of the Society for Car-diac Angiography and Interventions. I. Results and complications.Cathet Cardiovasc Diagn 1989;17:5–10; and Noto TJ Jr, Johnson LW,Krone R, et al. Cardiac catheterization 1990: A report of the Registryof the Society for Cardiac Angiography and Interventions (SCA&I).Cathet Cardiovasc Diagn 1991;24:75–83.

Chapter 5 Diagnostic Coronary Angiography · 2009. 6. 12. · descending coronary artery arises...

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