Coronary angiography

In October 1958, F Mason jr. Sones presented the first unintentional selective coronary arteriogram at the Cleveland Clinic. During an injection into the aortic root, the catheter accidentally slipped into the ostium of the right coronary artery and filled it with contrast medium (Cheng 2003).

The first selective coronary angiography was performed in 1962 by Sones and Shirley EK via a brachial access route.

Judkins performed this examination 5 years later via a femoral approach using specially shaped catheters.

Campeau described the first transradial approach in 1989 (Gotthardt 2017).

Coronary angiography is an invasive procedure for radiological imaging of the lumen of the coronary vessels using a water-soluble, iodine-containing contrast medium (Schünke 2009). During coronary angiography, the central aortic pressure, the pressures in the left ventricle and the pump function of the left ventricle can be assessed (Gotthardt 2017). For therapeutic reasons, percutaneous transluminal coronary angioplasty for revascularization of occluded coronaries can be performed immediately after coronary angiography (Hombach 2001). In recent years, non-invasive methods for imaging coronary morphology have increasingly developed, such as magnetic resonance imaging (cardiac MRI) and computed tomography (cardiac CT) (Lapp 2014).

The coronary vascular system consists of a total of two arteries: the arteria coronaria sinistra (LCA) and the arteria coronaria dextra (RCA), which are both divided into various branches (Schünke 2009).

Arteria coronaria sinistra: Above the level of the right coronary ostia, in the upper part of the left sinus valsalva, the left coronary artery (LCA) originates from the left coronary sinus of the ascending aorta. It consists of a short (1 - 3 cm) main trunk, which in the further course usually turns into a

• Ramus interventricularis anterior (RIVA or LAD), which divides the anterior wall of the left ventricle, the anterior parts of the interventricular septum and the apex by several diagonal and septal branches and divides them into a
• Ramus circumflexus (RCX), which runs to the apex of the heart or around the apex of the heart and supplies the lateral wall and part of the inferior wall of the left ventricle through several Rr. marginalis It can also be designed as a short vessel that does not reach the apex of the heart and is divided into several small branches. In such a case the ramus interventricularis posterior of the right coronary artery is strongly developed.

In about 20% of all patients, the left main trunk divides into three coronary arteries instead of two. The additional coronary artery is called

• Ramus intermedius. This corresponds to a diagonal branch of the RIVA or a marginal branch of the RXC in the supply area. In 40% of the patients the sinus node artery originates from the R. circumflexus. In about 4% of all patients the left main stem is missing, so that the RIVA and the RCX originate directly from the aortic root (Alkadhi 2009 / Lapp 2014).

Arteria coronaria dextra: The right coronary artery (RCA) originates from the right coronary sinus of the aortic root.

In the proximal third, the mostly small-caliber branches of

• ...of the conus and sick sinus artery. The conus artery (KA) draws towards the pulmonary conus.

The sinus node artery (SKA) originates from the right coronary artery in 60% of patients. It runs across the atrial septum, where it branches out into several branches that lead to the sinus node and the right and left atrium. In the middle third of the right coronary artery, several branches extend to the anterior wall. In the area of the crux cordis or just before it, it then divides into its two end branches:

• Ramus interventricularis posterior (RIVP). This branch moves towards the apex of the heart and supplies the diaphragmatic part of the interventricular septum with several septal branches.
• and the ramus posterolateralis dexter (RPLD). The RPLD supplies the diaphragmatic wall of the left ventricle. The AV nodal artery often emerges from this vessel, which is divided into several fan-shaped branches, at a right angle. This vessel draws towards the right coronary sinus (Alkadhi 2009 / Lapp 2014).

In a country comparison, Germany performs the most interventions with 7.237 coronary angiographies per million inhabitants, followed by Belgium with 5.279 coronary angiographies per million inhabitants.

Sweden is in second last place with 2.863 coronary angiographies per million inhabitants, followed by Poland with 1.386 coronary angiographies per million inhabitants. Taken from the register of the K.-L. Neuhaus Data Centre from 2001 to 2002 (Gottwik 2003)

Coronary angiography remains the gold standard in assessing coronary morphology for patients with suspected or known coronary artery disease. However, the indication should be carefully established to assess the optimal therapeutic intervention for the patient (Pinger 2019).

Indications for coronary angiography include.

• Coronary heart disease
  • Acute myocardial infarction (both STEMI and NSTEMI).
  • Control in the postinfarction phase
  • unstable angina
  • stable exertional angina
  • patients with characteristics of high risk and so far unclear non-invasive diagnosis
• preoperative diagnosis of coronary arteries in case of planned surgery or intervention of congenital or acquired vitiation: preoperative coronary angiography is recommended in all patients over 40 years of age, as they often have advanced sclerosis of the coronary arteries, which cannot be diagnosed with certainty by cardiological functional tests. In younger patients, preoperative coronary angiography should be performed only after consultation with the attending cardiac surgeon. However, if risk factors for coronary artery disease are present, the indication should be generous (Lapp 2014).
• Preoperative diagnosis of the coronaries before planned surgery of the thoracic aorta due to dissection or aneurysm: In the case of artherosclerotic cause of aortic disease, there is indeed a high coincidence with coronary artery disease. However, consultation with the cardiothoracic surgeon is recommended, as regular coronary angiography would not be indicated in acute type A dissection, for example, because of the risk and time delay to surgery (Lapp 2014).
• Heart failure of unclear etiology with an impaired left ventricular ejection fraction (LVEF) <50% (Stierle 2017). In many cases, the cause of heart failure is coronary artery disease and not a consequence of dilated cardiomyopathy. Because therapeutic measures and thus prognosis vary widely, invasive diagnostic coronary angiography is recommended (Lapp 2014).
• Control in Z. n. percutaneous transluminal coronary angioplasty (PCI) of high-risk patients.
• Ventricular tachycardia.

Coronary artery disease is often the cause of tachycardia. Therefore, coronary angiography should be part of the diagnosis in this case as soon as the cause of the ventricular tachycardia could not be found by noninvasive examinations (Lapp 2014).

• After a survived sudden cardiac death, the cause of which remained unexplained.
• for exclusion diagnosis in patients with recurrent unclear thoracic pain and concurrent inconspicuous non-invasive findings.

However, this symptom is only a relative indication for coronary angiography. The indication should be made with caution, taking into account the complications and risks of the procedure. Alternatively, the above-mentioned non-invasive measures such as cardio- CT or cardio- MRI can be considered here (Lapp 2014).

Indication according to ESC 2013:

• Recommendation grade / Evidence grade I / C: This grade of recommendation includes patients with angina pectoris CCS III or at probable high risk of events, especially with inadequate response to medical treatment. Patients at high risk according to the non-invasive risk evaluation, provided that revascularization is likely to improve prognosis. In this patient group, coronary angiography is indicated even if there is little or no symptomatology of symptoms.
• Grade of Recommendation / Level of Evidence IIa / C: This group includes patients with incongruent or conflicting findings in whom risk evaluation should be performed. Of note, the level of evidence is always weak (Pinger 2019).

No indications are:

• lack of willingness of the patient to undergo revascularizing therapy
• In the presence of lack of therapeutic consequences
• In patients with high comorbidity, if the risk of coronary angiography is greater than the benefit from confirming the diagnosis

(Herold 2020)

Contraindications:

Absolute contraindication exists in case of:

• general refusal of a possibly necessary revascularization
• Lack of prospect of improvement in quality of life or life expectancy (Pinger 2019).

Relative contraindication exists in:

• presence of active bleeding
• severe coagulopathy
• acute and previously untreated infection
• existence of an unexplained fever
• decompensated heart failure
• pulmonary edema
• acute renal failure
• acute apoplexy
• severe anemia
• manifest hyperthyroidism
• uncontrolled hypertension
• digitalis intoxication
• severe symptomatic electrolyte imbalance
• an anaphylactic reaction to contrast media proven by documentation
• presence of a severe, life-limiting illness
• lack of patient cooperation due to mental or systemic illness (Pinger 2019).

Complications and risks:

• INR should be < 2.0: However, it has been shown that no increased bleeding complications occurred when interruption of oral anticoagulation was omitted.
• Metformin: Metformin administration should be interrupted no later than the day of the study. Continue therapy only after creatinine levels are stable (this is usually the case after 48 h).
• Anaphylaxis: The risk of recurrence of anaphylaxis can be reduced by H1 and H2 blockers and by cortisone.
• Periprocedural apoplexy: To date, there is no established therapy for periprocedural apoplexy. In the vast majority of cases, this is likely to be an embolism due to arteriosclerotic plaques. CCT to exclude bleeding should be performed in all cases (Pinger 2019).
• The mortality of the procedure is 0.15% on average.

Mortality for an emergency indication is higher than that for an elective procedure (Herold 2019). In the vast majority of cases, the causes of mortality are a consequence of acute myocardial infarction or arise from pump failure of the left ventricle (Lapp 2014).

• The incidence of myocardial infarction is 0.8%.

Cause may be dissection of the ostium or coronary emboli (due to air, atheroma, thrombi) (Lapp 2014).

• Triggering ventricular fibrillation 0.4%: Ventricular fibrillation can be triggered by a forceful injection of contrast into a small right coronary artery or a proximal side branch (Lapp 2014; Stierle 2017)
• Short-term asystole or bradycardia 0.06%: These can be triggered during contrast injection into the right coronary artery. Since in most cases they last only a few seconds, no further therapeutic measures are required in this case (Lapp 2014).
• Cerebrovascular ischemia / emboli 0.4%: These are caused by wall arterial thrombi, thrombi on the catheter or guidewire, or air emboli (Lapp 2014).
• Vascular complications in 0.3% (Stierle 2017).
• Occurrence of aneurysm spurium or AV fistulae at the puncture site.
• Vascular spasm: Spasm may occur during probing of both vessels, but preferably in the area of the right coronary artery. Because the spasm may be catheter induced, correction of the catheter should follow sublingual or intracoronary application of 0.4 - 1.0 mg nitroglycerin.
• acute renal failure
• Hematoma (Herold 2019).

Vascular access routes: Different access routes are available for coronary angiography:

Access via the femoral artery (so-called Judkins technique [Herold 2019 / 2020]):

Here, the right femoral artery is predominantly punctured.

The advantages are

• technically simple and quickly accessible puncture.

The disadvantages of femoral puncture are

• subsequent prolonged immobilization of the patient

• often - despite the use of current closure systems - additional manual compression is required

• occurrence of extensive hematomas

• risk of infection of the puncture site with subsequent abscessing

  • Formation of an AV fistula
  • Pressure damage to the femoral nerve (due to the anatomical proximity)
  • Formation of pseudo-aneurysms

Access via the radial artery (so-called modified Sones technique [Herold 2019 / 2020])

The advantages of radialis access are:

• local complications such as inflammation, compression of the nerves, AV fistulas and bleeding occur much less frequently
• compression time is shorter due to the small vessel diameter and anatomical location
• vagal reactions are less frequent
• the patient can be mobilized immediately

There are also advantages in the selective visualization of bypasses of the internal mammary artery. However, if bilateral mammary bypasses are to be visualized, the femoral approach is usually used. The disadvantages are that

• in older and/or obese patients, it is not uncommon to find strongly tortuous vascular courses
• calcifications of the upper extremity occur more frequently
• spasms of the artery can occur
• In addition, the radial artery is often difficult to puncture for the less experienced examiner,

Relative contraindications to radial access include:

• single-arm patients
• dialysis patients with a shunt in place
• Vasculitides
• M. Raynaud's disease
• pathological Allen test for the detection of circulatory disorders (however, this test has lost its importance in the meantime)
• multiple bypasses with simultaneous need to probe a contralateral internal mammary bypass
• Existing need to use large drill heads for rotablation (Gotthardt 2017).

A. brachialis access /A . subclavia access.

The latter two play a minor role (Hombach 2001).

In all patients - according to the current ESC guideline - the radial access route is indicated as the primary route, since both the RIVAL- study (Jolly 2011) and the RIFLE STEACS- study (Romagnoli 2011) demonstrated a significant difference in mortality and bleeding complications in favor of the radial access.

In all patients - according to the current ESC guideline - the radial access route is indicated as the primary route, since both in the RIVAL- study (RadIal Vs femorAL Access for Coronary Interventions [Jolly 2011]) and in the RIFLE STEACS- study (Radial Versus Femoral Randomized Investigation in ST-Elevation Acute Coronary Syndrome [Romagnoli 2011]) a significant difference regarding mortality (5.2% vs. 9.2%, p = 0.020) and bleeding complications (7.8% vs. 12.2%, p = 0.026) in favor of radial access was demonstrated.

The following diagnostic procedures can be additionally performed during coronary angiography:

• Coronary angioscopy (to assess vessel morphology and any plaques present).
• intravascular ultrasound (also used to assess vessel morphology and the presence of plaques)
• optical coherence tomography (OCT provides high resolution of luminal and intramural vascular structures)
• intracoronary Doppler flow measurement to determine the fractional flow reserve = FFR (a hemodynamically effective coronary stenosis exists from an FFR < 0.80 with a specificity of 100 %)

(Herold 2020)

Technical performance of the examination (Here, only a rough overview of the performance is given. For further details, see the relevant literature).

After local anesthesia with 1% igem lidocaine (Lapp 2014), the cutaneous puncture incision is made with a scalpel. The puncture needle is then advanced into the artery until pulsatile blood is emitted (Hombach 2001). A guide wire is advanced over the puncture cannula, then the puncture cannula is removed and the flexible sheath is inserted into the access artery over the guide wire (Kasper 2015). After removal of the stylet, the guide wire is pushed against the blood flow toward the aortic root. Care should be taken to ensure that advancement occurs without resistance or pain to the patient. Specially preformed catheters can then be pushed over this guide wire to the respective ostium of the target coronary artery (Gotthardt 2017). There are - depending on the type of intervention and the anatomical conditions - differently shaped catheters (e.g. Judkins catheter, Amplatz catheter, coronary bypass catheter, Sones catheter, multipurpose catheter, etc.) [Lapp 2014]. [Lapp 2014]). The catheter is advanced under fluoroscopy to check its position.

The puncture of the left and right coronary artery is often performed using the Judkins technique (Lapp 2014). It is preferably used for femoral access, but is also possible for radial access. The left coronary artery is usually probed in the 40-degree left anterior oblique (LAO) projection, and the right coronary artery is probed in the 60-degree or 40-degree left anterior oblique (LAO) projection (Lapp 2014). However, there are other techniques for probing the ostium, such as the Sones technique.

This technique is preferably used for the brachial approach. Here, the left coronary artery is probed in a left oblique position (40 degrees LOA), the right coronary artery analogously with clockwise rotation of the catheter (Lapp 2014).

Amplatz catheter: This catheter is the first choice for radial access. It can also be used in femoral access, preferably when the Judkins catheter is not suitable to intubate the ostium of the coronary artery (Hombach 2001). The left coronary artery is probed in 40 degrees LAO or in 30 degrees RAO, the right in 60 degrees LAO (Lapp 2014) (Erdmann 2009).

The amount of contrast agent injected and the speed of injection should be adjusted to the coronary flow. Approximately 2 ml - 8 ml is injected into the right coronary artery, and approximately 7 ml - 10 ml is injected into the left coronary artery. The injection time is approximately 1s - 2s. Any air embolization must be avoided at all costs. Therefore, before each injection, the syringe should be completely filled with contrast medium, not completely emptied and the syringe head should always be held downwards (Lapp 2014).

Subsequent imaging of the coronaries is performed under continuous aortic pressure measurement (Gotthardt 2017).

For the left coronary artery, there are 6 standard projection planes:

1st RAO 5 - 15 degrees

2. RAO 30 degrees caudal 20 degrees

3. RAO 10 - 30 degrees cranial 20 degrees

4. LAO 50 - 60 degrees cranial 20 degrees

5. LAO 40 - 50 degrees caudal 20 degrees

6 Left lateral projection (90 degrees) (Lapp 2014).

For the right coronary artery, 3 planes of projection are available:

1. LAO 60 degrees (40 degrees)

2. LAO 40 - 45 degrees cranial 15 degrees

3. RAO 30 - 40 degrees

(Lapp 2014)

Complementary diagnostics: In the context of coronary angiography, the following complementary diagnostics can also be performed:

• Coronary angioscopy

It is used to visualize intracoronary thrombi, etc. [Hess 2000])

• intravascular ultrasound (IVUS)

This provides detailed information about lumen and wall structure [Bolz 2002].

• optical coherence tomography (OCT) for visualization of intramural and luminal vascular structures
• intracoronary Doppler flow measurement to determine fractional flow reserve (FFR) used to measure the hemodynamic effectiveness of a stenosis (Herold 2019).

Occlusion systems: After successful visualization of the coronary arteries, the punctured artery must be occluded again. This can be done by different occlusion systems:

Collagen- closure systems: These include, for example, the Angio- Seal, VasoSeal, Duet system. Successful hemostasis is achieved in about 90% of patients. The advantages of this method include

• easy handling
• the rapid mobilization after 4 - 6 hours

Contraindications are:

• infections in the puncture area
• known allergies to the components of the closure system
• puncture must not be repeated before 3 months have elapsed
• application in case of a lock in the A. femoralis profunda is not possible, because then the collagen would be deposited in the A. femoralis superficialis
• No application after puncture of the dorsal vessel wall or after malpuncture (Lapp 2014).

Suture closure systems: These include, for example, the Perclose system. The success rate is also about 90%.

The advantage of this method is

• large puncture sites (up to 10 F) can also be closed.

The disadvantages are

• more complicated handling
• Necessity of a certain amount of practice

The suture closure system should not be used in cases of:

• considerable calcification of the femoral artery
• already existing vascular prosthesis

Clip- systems: Among the clip- systems are e.g. Starclose and Angiolink.

The advantages of this system are

• can also be used on heavily calcified vessels
• the vessel can be punctured again immediately afterwards.

The only disadvantage is the somewhat more difficult handling - compared to the collagen systems (Lapp 2014).

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