What are 3 groups of people seen in the cath lab?
1. Primary angioplasty to open clogged artery, 2. acute coronary syndrome-nonSTeMI (within 72h), 3. More elective (large portion) with risk factors and adverse stress test
Contraindications to cardiac cath and angiography
1. Uncontrolled ventricular irritability, 2. Uncorrected hypokalemia or digitalis toxicity, 3. Uncorrected hypertension (risk for MI), 4. Intercurrent febrile illness, 5. Decompensated heart failure, especially with pulmonary edema (relative, depending), 6. Anticoagulated state, 7. Severe allergy to contrast, 8. Severe renal insufficiency, underlying renal damage, diabetics and dehydration
What is the risk of death/complications in angioplasty and diagnostic cath lab?
Extremely low and lower for diagnostic cath.
Benefit of arterial access through the femoral artery
Easy to find
Drawback of femoral artery
Need to press down hard to stop bleeding after removal. Pt always needs to lie down for several hours afterwards. Like in angioplasty, give coagulation. Increased risk of bleeding and hematoma in that area. Especially problematic for elderly needing to get up to widdle every hour.
Benefits of radial arterial access
Low rate of bleeding and hematoma, patient can sit up with pressure bandage and eat/drink, etc.
How to decide if the radial artery can be used for angioplasty?
The Allen test: check to see if arteries are patent. Palpate radial and ulnar and block them off. Pt makes a fist, when opens goes white. Open ulnar and if hand gets reperfused, know it's patent.
What is the complication of doing angiography on a radial artery with a small ulner artery?
Necrotic damage through the hand
Steps of angiography
1. Anesthetize locally (can also sedate if frightened), 2. Stick wire in and once the wire is through the needle, forms J inside the artery and if meets resistance bends and doesn't cause any damage. 3. Then take needle out and leave wire in the artery. 4. Then insert sheath/introducer. Tube has one-way valve so trocal can go in but blood can't come out. 5. Cut a nick with a scalpel in the skin to get sheath and dilator in. 6. Pass sheath over wire. 7. Remove introducer and tube remains.
What is a sheath/introducer for angiography
Internal trocal and hollow tube connected to sidearm with insert for saline or anything want to insert.
What is the difference between the right and left Judkins catheters?
Left is more bent to get around aorta and through LCA.
How is the insertion of the catheter visualized?
X-ray performed once inserted, inject dye in coronary vesselsand see lumen but can't tell about vessel wall.
What is angiography used to assess?
Stenosis due to atherosclerosis and instent neointimal proliferation.
What is IVUS (Intra-vascular Ultrasound)?
Thin wire/transducer passed down into blood vessel lumen and coronary vessels, connected to an ultrasound machine. Waves reflect back and can see lumen and vessel wall tomographically like a histological cross section.
How is IVUS data used?
Both for research and clinical purposes: stenoses, optimization of stent deployment.
What are the primary defects seen with IVUS?
Calcifications, dissections, plaques otherwise normal in angiography, in-stent restenosis
What is the path of right heart cathetrization?
By femoral approach or brachial or other, up femoral vein into inferior VC and into right atrium.
What catheter is used to test pressure normal wave forms?
Special catheter is hollow with inflatable balloon at the tip.
How is the normal wave form measured?
Catheter is passed into venous (right) side through distal end and can connect through outside of patient to pressure transducer. Can get reading of pressure in whatever part of the heart you're in. Wave form with particular pressures. Advance catheter further, get typical pressure wave from RV, further, pulmonary artery, then pulmonary capillary wedge pressure. Inflate balloon from outside, wedge into small space tightly and can only register pressure in distal portion.
Normally what vessels are the same pressure as the distal pulmonary arteries?
Pulmonary arterioles, pulmonary capillaries, and pulmonary venous pressure, reflecting LA pressure (reflecting LVEDP)
What happens to the pressure measured in the left atrium during mitral valve stenosis?
Higher than LVEDP, the bigger the differential, the more severe the stenosis.
How are ASD and VSD measured in cardiac cath?
Can take blood out of different sections of the heart and measure oxygen. If there is a sudden increase in oxygenation in the RA-ASD. If in RV-VSD.
How is a pigtail catheter used?
Inserted into the LV with a large volume of dye to opacified left lumen. Can see heart contracting, space of lumen of vessel colored by contrast medium so can see contraction.
How can angioplasty be used in angina or ischemia?
Open blocked or stenotic artery using a thin wire and then a simple small balloon passed down into artery.
What are the limitation of balloon angioplasty?
Arterial wall is elastic so bounces back and can cause narrowing (recoil, tissue prolapse, dissection). Late restenosis.
When does restenosis occur?
In almost any angioplasy or stent (but 30% less) placement. In inflated stent endothelium is destroyed and neointima will form over it in about 3 months.
In-stent restenosis/intimal hyperplasia
Tissue grows through struts/metal, blocks of lumen again, overcome by drug eluting stents that interfere with cell cycle. Prevents multiplication of regenerating cells.
What is the disadvantage to drug-eluting stents?
Because metal is exposed for longer before covering up, stent is thrombogenic for longer period, need to continue anticoagulant longer.