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Cardiac Catheterization
andCoronary Angiography
Andre Tritansa FaizalNurnajmia Curie Proklamatina
Resource Person: dr. Doni Firman, SpJP (K)
History
Eric J. Topol (ed). Textbook of Cardiovascular Medicine, 3rd ed. 2007www.heartviews.org
Definition
Cardiac Catheterization• A procedure use catheter that inserted to measure
pressures in the heart chambers, to determine cardiac output and vascular resistances and to inject radiopaque material to examine heart structures and blood flow
Pathophysiology of Heart Lily 6th Ed 2015
Indication of Diagnostic Cardiac Catheterization
to confirm or exclude the presence of a condition already suspected from the history, physical examination, or noninvasive evaluation;
to clarify a confusing or obscure clinical picture in a patient whose clinical findings and noninvasive data are inconclusive;
to confirm the suspected abnormality and to exclude associated abnormalities that may require a surgeon's attention in patients for whom corrective surgery is contemplated
Eric J. Topol (ed). Textbook of Cardiovascular Medicine, 3rd ed. 2007
Relative Contraindication to Diagnostic Cardiac Catheterization
Bonow RO, et al (eds). Braunwald Heart Disease: A Textbook of Cardiovascular medicine. 10th Edition, 2015.
50%→ outpatient procedure Indication for postprocedural hospitalization:
Hematoma formationDiagnosis post procedure eg. Severe LM, proximal 3VDUncompensated HF, unstable ischemic symptoms, severe
AS with LV dysfunction, renal insufficiency, continuous anticoagulation
Bonow RO, et al (eds). Braunwald Heart Disease: A Textbook of Cardiovascular medicine. 10th Edition, 2015.
Technical Aspect of Cardiac Catheterization
Preparation of the Patient
• Explain the procedure, risk and benefit• Pre-cath evaluation:history, physical exam, ECG, CBC,
electrolyte, creatinin, blood glucose, PT with INR• Fasting for 6 hours• Premedication: sedation, antihistamine• Discontinue oral anticouagulant 3 days before, INR < 1.8• Discontinue metformin until stable renal function for 48 hrs• Hydration pre and post procedure
Bonow RO, et al (eds). Braunwald Heart Disease: A Textbook of Cardiovascular medicine. 10th Edition, 2015.
Right Heart Catetherization
• Measurement and analysis of: Right atrium Right ventricle Pulmonary artery, pulmonary capillary wedge
pressure Cardiac output screening of intracardiac shunts
• Performed antegrade through IVC or SVC• Entry via femoral, internal jugular, subclavian, antecubital
vein
Bonow RO, et al (eds). Braunwald Heart Disease: A Textbook of Cardiovascular medicine. 10th Edition, 2015.
Bonow RO, et al (eds). Braunwald Heart Disease: A Textbook of Cardiovascular medicine. 10th Edition, 2015.
From Baim DS, Grossman W: Percutaneous approach, including transseptal and apical puncture. In Baim DS, Grossman W : Cardiac Catheterization, Angiography, and Intervention. 7th ed. Philadelphia, Lea & Febiger, 2006, p 86.)
Balloon Flotation Catetherization
Left Heart Catetherization
The Judkins Technique
Bonow RO, et al (eds). Braunwald Heart Disease: A Textbook of Cardiovascular medicine. 10th Edition, 2015.
Left Heart Catetherization
Modified Seldinger Technique
Bonow RO, et al (eds). Braunwald Heart Disease: A Textbook of Cardiovascular medicine. 10th Edition, 2015.
Hemodynamic Data
• Pressure measurement• Measurement of Flow• Determination of vascular resistance
Ohm’s Law:
Q= ΔP/R
Normal Right and Left Heart Pressure Recorded from Fluid Filled Catheter in Human
Pepine C,Hill JA, Lambert CR (eds). Diagnostic and Therapeutics Cardiac Catheterization.3rd ed. 1998
Normal Pressure
Bonow RO, et al (eds). Braunwald Heart Disease: A Textbook of Cardiovascular medicine. 10th Edition, 2015.
Method Most reliable Least reliableFick Low cardiac output High cardiac output
Thermodilution High cardiac output Pulmonic regurgitation
Tricuspid regurgitation
Intracardiac shunting
Angiographic Normal-shaped ventricle
Extensive segmental wall motion abnormalities
arrhytmia
Aortic regurgitation
Mitral regurgitation
Eric J. Topol (ed). Textbook of Cardiovascular Medicine, 3rd ed. 2007
Cardiac Output Measurement
Bonow RO, et al (eds). Braunwald Heart Disease: A Textbook of Cardiovascular medicine. 10th Edition, 2015.Thermodilutio
n
Fick method
Bonow RO, et al (eds). Braunwald Heart Disease: A Textbook of Cardiovascular medicine. 10th Edition, 2015.
Shunt Quantification
Flamm formula
Flow ratio
Systemic Vascular Resistance
Pulmonal Vascular Resistance
Bonow RO, et al (eds). Braunwald Heart Disease: A Textbook of Cardiovascular medicine. 10th Edition, 2015.
Physiologic & Pharmacologic Maneuvers
Dynamic exercise Pacing Tachycardia Physiologic stress → The Valsalva maneuver, Kussmaul sign Dobutamine infusion→ indicated in low flow, low gradient
AS Inhaled NO→ pulmonary hypertension Sodium nitroprusside→predict good clinical outcome in
dilated cardiomyopathy and MR
Bonow RO, et al (eds). Braunwald Heart Disease: A Textbook of Cardiovascular medicine. 10th Edition, 2015.
Adjunctive Diagnostic Technique
LV Electromechanical MappingDistinguish viable and non viable myocardium, ischemic
and non ischemic myocardiumPredict recovery of function after revascularizationGuiding stem cell injection
Intracardiac Echocardiography (ICE)Provide imaging of interatrial or interventricular septum
and left heart structuresGuidance of percutaneous ASD and PVO closureLocalization of fossa ovalis for transseptal puncture
Bonow RO, et al (eds). Braunwald Heart Disease: A Textbook of Cardiovascular medicine. 10th Edition, 2015.
Coronary Angiography
Outline
• Overview• Indications and Contraindications• Complications• Technique• Pitfalls
Overview
• Coronary angiography: imaging technique that uses X-rays to take coronary vessels pictures
• Remains standard to identify presence/absence of arterial narrowings related to CAD
• Most reliable anatomic information for determining appropriateness of medical therapy
• 1st performed by Mason Sones (1959), methods have improved substantially since then
How is Coronary Angiography Done?
http://patient.info/health/coronary-angiography
Coronary Angiography Principle• Radiation from x-ray tube is
attenuated as passes through body, detected by image intensifier
• Contrast injected to coronaries enhances x-rays absorption sharp contrast with tissues
• X-ray shadow converted to visible light image, displayed on fluoroscopic monitors, stored on digital storage system
• Flat-panel detectors replace image intensifiers (reduce radiation exposure, enhance image quality)
Bonow RO, et al. Braunwald Heart Disease. 9th Edition, 2012.
Radiation Exposure (1)• 2 forms of radiation injury:
• Deterministic injury result in cell death and organ dysfunction (dose-dependent, most commonly result in skin injury)
• Stochastic injury result in genetic mutations (not dose-dependent)
• Radiation dose is measured as:• Total radiation exposure,
determined from x-ray tube output, expressed as dose-area product (DAP)
• Interventional reference point (IRP) dose, est. radiation dose to patient’s skin
Kern M. Do You Know Your Radiation Dose During Your Cath? Cath Lab Digest. Volume 19 - Issue 6 - June 2011
Radiation Exposure (2)
Kern M. Do You Know Your Radiation Dose During Your Cath? Cath Lab Digest. Volume 19 - Issue 6 - June 2011
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Contraindications
• No absolute contraindications• Relative contraindications:
• unexplained fever• untreated infection• severe anemia or active bleeding• critical electrolyte imbalance• uncontrolled systemic hypertension• digitalis toxicity• ongoing stroke• acute renal failure• decompensated heart failure• severe intrinsic or iatrogenic coagulopathy (elevated INR)• active endocarditis
Complications
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Technique of Coronary Angiography
Patient Preparation
• Lab exam <2 weeks prior: Hb, platelet, electrolyte, creatinine, PT (warfarin, liver disease, coagulopathy)
• Continue aspirin, UFH, LMWH, GP IIb/IIIa inhibitor• Discontinue warfarin (3 days prior), target INR ≤1.8 (femoral), ≤2.2
(radial), may treat with UFH/LMWH • Discontinue dabigatran 24 hrs prior (GFR >50 mL/min), 48 hrs prior
(GFR 30-50 mL/min)• Discontinue metformin prior until renal function normalized post
procedure
Vascular Access (1)• Depends on operator-patient preferences,
anticoagulation status, peripheral vascular disease
• Femoral artery approach• Most commonly used• Puncture site distal to inguinal ligament, prox to
bifurcation of superficial & profunda femoral artery
• Bed rest for 1-2 hours after removal of 4-5F sheath and 2-4 hours of 6-8F sheath, longer if there is higher risk of bleeding
• Brachial artery approach• Preferred to femoral in presence of severe
peripheral vascular disease and morbid obesity• Easily accommodates 8F (1F = 0.33-mm
diameter) sheath • Risk of blood supply compromise to forearm
and hand in event of a vascular complication
http://www.myheart.com.pk/angiography/
Davidson CJ, Bonow RO. Cardiac catheterization. In: Braunwald’s Heart Disease 10th edition. 2015
Vascular Access (2)• Radial artery approach• Preferred to brachial due to ease of
catheter entry & removal; dual blood supply to hand
• UFH (up to 5000 U)/bivalirudin for brachial & radial artery approaches
• Hydrophilic sheath and I.A. verapamil & NTG reduce spasm
• Factors assoc. with unsuccessfulness: high-bifurcation radial origin, full radial loop, extreme radial artery tortuosity
• Immediate ambulation; compared to femoral: lower cost, improve coronary visualization, reduce bleeding complications
• Generally accommodate 4-6F catheters
Allen test prior to procedure (ulnar arterial flow adequacy)
http://www.premierhealthspecialists.org/
Watson S, Gorski KA. Invasive Cardiology: A Manual for Cath Lab Personnel. 3rd Edition. 2011.
Catheters• Polyethylene/polyurethane with fine wire braid within wall to allow
advancement and directional control and prevent kinking• Outer diameter size 4-8F (5-6F most common for diagnostic
arteriography)
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
• JL catheter is preshaped to allow entry into LCA from femoral with minimal manipulation (JL 4.0); for left/right brachial/radial artery 0.5 cm less curvature than for femoral is better suited
• JR catheter is preshaped to permit entry into RCA with small amount of rotational (clock-wise) manipulation from any vascular approach
• Catheter selection is based on habitus and aortic root size
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Judkins Catheters
• Femoral or brachial approach• Excellent alternative in cases in
which Judkins catheter is not appropriately shaped to enter coronary arteries
• Amplatz L-1 or L-2 may be used from right brachial or radial approach
• Modified Amplatz right catheter (AR-1 or AR-2) can be used for engagement of a horizontal or upward takeoff RCA or SVG
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Amplatz Catheters
Other Catheters
• IMA left catheter with angulated tip allows engagement of IMA or upward takeoff RCA
• Catheter shapes that permit engagement of SVGs include multipurpose catheter and Judkins right, modified Amplatz right, and hockey stick catheters
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Drug Used (1)• Analgesics
• Conscious sedation (respond to verbal commands; maintain patent airway)• Diazepam 2.5-10 mg orally, diphenhydramine, 25-50 mg orally, 1 hour prior• I.V. midazolam 0.5-2 mg, fentanyl 25-50 μg for sedation during procedure
• Anticoagulants• IV UFH no longer routinely required• Increased thromboembolic risk (severe AS, critical PAD, arterial
atheroembolism, undergoing >1-2 min use of guidewires in central circulation) may be given I.V. UFH 2000-5000 U
• Brachial/radial artery catheterization should receive systemic UFH/bivalirudin
• Frequent catheters heparinized saline flush prevent microthrombi formation within catheter tip
• Continuous flush through arterial access sheath may lower distal thromboembolism
• Anticoagulant effect of UFH can be reversed with protamine 1 mg for every 100 U of heparin
Drug Used (2)
• Treatment of Periprocedural Ischemia• Angina induced by tachycardia, hypertension, contrast agents,
microembolization, coronary spasm/enhanced vasomotor tone, or dynamic platelet aggregation
• NTG SL (0.3 mg), I.C. (50-200 μg), or I.V. (10-25 μg/min) in SBP >100 mm Hg• No contraindication to BB: I.V. metoprolol 2.5-5.0 mg/propranolol 1-4 mg• IAB counterpulsation as adjunctive in coronary ischemia and left main CAD,
cardiogenic shock, or refractory pulmonary edema
• May produce adverse hemodynamic, electrophysiologic, renal effects• Side effects frequency varies depends on ionic content, osmolality,
viscosity• Ionic agents:
• Dissociate into cations & iodine-containing anions• High serum osm (>1500 mOsm) hypertonic• SB, heart block, QT & QRS prolongation, ST depression, giant T inv,
decreased LV contractility, decreased SBP, increased LVEDP; calcium-chelating properties also contribute to cardiac effects
• Non ionic agents:• Do not ionize in solution, more iodine-containing particles per milliliter of
contrast material• Lower osmolality (<850 mOsm), do not chelate calcium, fewer side
effects • Side effects relate in part to hyperosmolality hot flush, nausea, vomit,
arrhythmia
Contrast Agent (1)
Contrast-Induced Nephropathy Contrast Reaction Prophylaxis
• Worsening renal fx (10-20%), esp. previous renal insuff, DM, dehydration, HF, large contrast volume, ≤48 hrs exposure to contrast highest risk: DM, eGFR <60 mL/min
• Fluid administration I.V. saline/sodium bicarbonate 1-1.5 mL/kg/min for 3-12 hours before procedure and 6-12 hours after procedure
• Rx to contrast agents:1. Mild (9%)—grade I: single episode of
emesis/nausea/sneezing/vertigo2. Moderate (9%)— grade II: hives or multiple
episodes of emesis/fevers/chills3. Severe (0.2-1.6%)— grade III: shock,
bronchospasm, laryngospasm/edema, unconscious, hypotension, hypertension, arrhythmia, angioedema, pulmonary edema
• Prophylactic H1 & H2 receptor–blocker (diphenhydramine 50 mg, cimetidine 300 mg) and aspirin
• Severe previous rx: prednisone 60 mg night before & 2 hours prior
Contrast Agent (2)
Anatomy and Variations of Coronary Arteries
• Major epicardial and 2nd-3rd order branches can be visualized by coronary arteriography
• Smaller intramyocardial branches are not seen due to their size, cardiac motion, limitations in angiographic systems resolution
• Smaller vessels perfusion quantitatively assessed by myocardial blush score prognostic in STEMI and those undergoing PCI
Smithuis R, Willems T. Coronary anatomy and anomalies. RadiologyDepartment of the Rijnland Hospitaland the University Medical Center Groningen. http://www.radiologyassistant.nl/
Arterial Nomenclature and Extent of Disease
• Major coronary arteries : LAD, LCx, RCA (dominance defined by presence of posterior descending and adjacent posterolateral branch)
• CAD is defined as ≥ 50% diameter stenosis in ≥1 of these vessels• Subcritical stenoses <50% are characterized as nonobstructive CAD• Obstructive CAD is classified as one-, two-, or three-vessel disease
BARI-CASS Coronary Artery Nomenclature
Alderman, et al. Native coronary disease progression exceeds failed revascularization as cause of angina after five years in the bypass angioplasty revascularization investigation (BARI). J Am Coll Cardiol. 2004;44(4):766-774.
Major determinants of 6-year outcome: number of diseased vessels, number of diseased proximal segments, and global LV function accounted for 80% of the prognostic information
Syntax Score
http://www.medscape.com/
Angiographic Projections• Heart is oriented obliquely in thoracic cavity RAO and LAO
projections to furnish true posteroanterior and lateral views of heart, limited by vessel foreshortening & branches superimposition
• Simultaneous x-ray beam rotation in sagittal plane provides better view:• Cranial view: image detector is tilted toward patient’s head• Caudal view : image detector is tilted down toward patient’s feet
• Optimal angiographic projection depends on body habitus, variation in coronary anatomy, location of lesion
• Recommendation:• Both LAO and RAO projections with both cranial and caudal angulation• At least two views of LCA and RCA
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Left Coronary Artery (1)
• LMCA• Arises from superior portion of left
aortic sinus, just below sinotubular ridge of aorta
• Diameter 3-6 mm, length 10-15 mm
• Courses behind RVOT and bifurcates into LAD and LCx
• Rarely absent LAD and LCx have separate ostia
• Best visualized: AP projection 0-20°caudal angulation
• Should view several projections with vessel off the spine to exclude LMCA stenosis
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10th edition. 2015
Left Coronary Artery (2)• LAD
• Courses along epicardial surface of anterior IV groove toward apex
• RAO projection: extends along heart anterior aspect
• LAO projection: passes down cardiac midline, between RV & LV
• Major branches:• Septal branches arise at
approximately 90° angles and pass into IVS, varying in size, number, and distribution
• Diagonal branches pass over anterolateral aspect of heart
- Best angiographic projections for LAD :
• LAO cranial: midportion of LAD and separates diagonal and septal branches
• RAO cranial: proximal, middle, distal segments of LAD and separates diagonal branches superiorly and septal branches inferiorly
• AP cranial (20-40°): midportion of LAD, separating it from diagonal and septal branches
Left Coronary Artery (3)
•LCx• Courses within posterior (left) AV groove toward inferior IV groove• Supplying left PDA from distal continuation of LCx (15%)• Remaining patients, distal LCx varies in size and length, depending on
number of posterolateral branches supplied by distal RCA• Gives off 1-3 large obtuse marginal branches as it passes down AV groove
principal branches of LCx, supply LV lateral free wall• Gives rise to 1-2 LA Cx branches supply lateral and posterior LA • RAO and LAO caudal: prox & mid LCx and obtuse marginal branches• AP or 5-15° RAO caudal: origins of obtuse marginal branches• LAO cranial: left PDA if LCA is dominant
Right Coronary Artery (1)• Originates from right anterior aortic sinus, inferior to origin of LCA,
passes along right AV groove toward crux • First branch conus artery, arises at RCA ostium or within first few mm
of RCA (50% of patients). Remaining patients, arises from separate ostium in right aortic sinus just above RCA ostium
• Second branch sinoatrial node artery, arises from RCA in <60% patients, LCx artery <40%, and both arteries with a dual blood supply in remaining cases
• Midportion of RCA usually gives rise to one /several medium-sized acute marginal branches supply anterior wall of RV and may provide collateral circulation in LAD occlusion
Right Coronary Artery (2)• RCA terminates in PDA and one/more RPL branches• RCA traverses both AV and IV grooves multiple projections are
needed to visualize each segment• LAO ± cranial/caudal angulation: ostium of RCA• Left lateral view: ostium of RCA in difficult cases, identified by reflux
of contrast material from RCA, which also delineates aortic root with swirling of contrast in ostium region
• LAO cranial/caudal: proximal RCA, but markedly foreshortened in RAO projections
• LAO cranial, RAO, and left lateral projections: mid- portion of RCA• LAO cranial or AP cranial: Origin of PDA, posterolateral branches• AP cranial or RAO projection: midportion of PDA
RCA Dominance• Dominant (85%)
• Supply PDA and at least one posterolateral branch (right dominant)
• PDA courses in inferior IV groove, gives rise to small inferior septal branches, which pass upward to supply lower portion of IVS and interdigitate with superior septal branches passing down from LAD
• After giving rise to PDA, RCA continues beyond crux cordis as right posterior AV branch along distal portion of posterior (left) AV groove, terminating in one or several posterolateral branches supplying LV diaphragmatic surface
• Nondominant/Left dominant (15%)• One half have left PDA and left posterolateral
branches that are provided by distal LCx• RCA is very small, terminates before reaching
crux, does not supply LV• Codominant/Balanced (remaining)
• RCA gives rise to PDA, LCx provide all of posterolateral branches
http://www.syntaxscore.com/
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Standardized Projection Acquisition• Each coronary artery should be visualized using different projections that
minimize vessel foreshortening and overlap• AP view + shallow caudal angulation often obtained first to evaluate LMCA • Other important views:
• LAO cranial (middle and distal LAD), leftward positioning of image intensifier should be sufficient to allow separation of LAD, diagonal, and septal branch
• LAO caudal (LMCA, origin of LAD, and proximal LCx)• RAO caudal (LCx and marginal branches)• Shallow RAO/AP cranial (mid and distal LAD)
• RCA at least two views (LAO & RAO):• LAO cranial (RCA and origin of PDA and posterolateral branches)• RAO (mid-RCA and proximal, middle, and distal termination of PDA)• AP cranial may be useful (distal termination of RCA)• Left lateral (ostium of RCA and midportion of RCA with separation of RCA and its
RV branches)
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Congenital Abnormalities of Coronary Circulation• Divided into those that cause
and do not cause myocardial ischemia
• Malignant features of anomalous coronaries: slitlike ostium, acute angle of takeoff, intramural course, significant compression between aorta and pulmonary trunk
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Myocardial Bridging• 3 major coronary arteries course
along epicardial surface• Occasionally, short segments
descend into myocardium for variable distance myocardial bridging (5-12%), usually LAD
• “Bridge” of myofibers passes over involved segment of LAD each systolic contraction cause narrowing of artery
• Angiography: bridged segment is of normal caliber during diastole, abruptly narrows with each systole
• No hemodynamic significance in most cases, may be associated with angina, arrhythmia, depressed LV function, myocardial stunning, early death after cardiac transplantation, SCD
Smithuis R, Willems T. Coronary anatomy and anomalies. Radiology Department of the Rijnland Hospitaland the University Medical Center Groningen. http://www.radiologyassistant.nl/
Assessing Lesion Complexity
• Heterogeneity of composition, distribution, and location of plaque results in unique patterns of stenosis morphology
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Popma JJ, et al. Coronoary ateriography and intracoronary imaging. In: Braunwald’s Heart Disease 10 th edition. 2015
Quantitative Angiography
• Quantitative analysis of digital angiograms:• Image calibration:
• Using contrast-filled diagnostic or guiding catheter as a scaling device, yielding a calibration factor in millimeters per pixel
• Arterial contour detection (mapping):• Drawing center line through segment of interest• Linear density profiles are constructed perpendicular to center line, and weighted
average of 1st and 2nd derivative functions is used to define catheter or arterial edges• Individual edge points are connected using automated algorithm, and outliers are
discarded and edges are smoothed• The automated algorithm is applied to selected segment, absolute coronary dimensions
& percent diameter stenosis are obtained
Pitfalls of Coronary Angiongraphy• Coronary angiography limitations:
• substantial interobserver variability• lack of correlation with functional measures with intermediate (40% to 70%)
stenoses• inability to identify vulnerable plaque lesions that may be predisposed to
rupture
• Technical factors can be mitigated at time of image acquisition to improve interpretations:
• Inadequate vessel opacification• Eccentric stenoses• Superimposition of branches• Microchannel recanalization
Inadequate Vessel Opacification
• Causes:• Increased native coronary flow in LVH, aortic insufficiency, or
anemia• Competitive filling from collateral branches or bypass graft
conduits• Catheter positioning that is not “in line” with coronary ostium• Use of a smaller (4F) injection catheter• Dislodgment of diagnostic catheter during injection of contrast
agent• Overcome by:
• Forceful injection of contrast agent so long as catheter tip position and pressure recording confirm safety of such a maneuver
• Switching to angioplasty-guiding catheter (soft, short tip, larger lumen than diagnostic catheter)
Eccentric Stenoses• Hemodynamic significance is dependent on percentage area
stenosis, not “worst” percentage diameter stenosis • Difficulty in ascertaining hemodynamic significance of eccentric and
bandlike lesions measurement of fractional flow reserve (FFR) with micromanometer-tip guidewire across abnormal region during I.V. adenosine
Superimposition of Branches
• Common LAD & parallel diagonal branches• May occur ostium of obtuse marginal branch of LCx & origin of RV
branch of RCA• Obtain sufficient angulation to identify exact anatomy at origin of
side branch• Cranial projections for LAD• Caudal projections for LCx• Left lateral projection for RCA
Microchannel Recanalization
• Angiography lacks resolution to differentiate 90% stenoses from recanalized total occlusions with microchannels & bridging collaterals
• Recanalization development of multiple tortuous channels small, close to one another, impression of single, slightly irregular channel
• Wire crossing may not be possible in some cases unless advanced wire techniques are used
Thank You