EXAM2/CH15- Revascularization of the Heart Flashcards
clinical procedures (for revascularization of the heart) may be elected for what 3 reasons
-restore myocardial blood flow
-symptom relief
-improved morbidity + mortality
4 common procedure types for revascularization of the heart
-angiography
-percutaneous transluminal coronary angioplasty (PTCA)
-stent therapy
-coronary artery bypass surgery (CABG)
angiography
IMAGING technique
what procedure is PTCA usually paired with
stent therapy
what is the most invasive procedure for revascularization of the heart
CABG
how does a coronary angiography work
catheter is inserted in leg + guided up to the aorta ->
catheter tip stops at left coronary artery ->
contrast agent is injected into arteries + x-ray imaging shows stenosis in left coronary artery
-dye shows plaque buildup occurring in the vessels
is coronary angiography an interventional procedure
NO, imaging
-it is done so the surgeon knows where they must intervene
what is often the first line of intervention
PTCA
what is PTCA also known as
heart catheterization
where does cath go through in PTCA
-radial artery in arm
-femoral artery in leg
-plasty means
to redistribute
percutaneous transluminal coronary angioplasty (PTCA)
-insertion of catheter to site of coronary lesion
-compression, redistribution, or removal of plaque
various techniques of PTCA (3)
-balloon angioplasty
-atherectomy
-laser angioplasty
PTCA techniques
balloon angioplasty
balloon catheter inflated to stretch vessel + increase diameter
-as the balloon inflates, it pushes the plaque to the size of the vessel wall; opens up lumen to revascularize
-ectomy means
removal/cutting out
PTCA techniques
atherectomy
plaque removal using blade catheter
-catheter has a blade tip but also has a vacuum tip to capture the plaque being dislodged
-in this technique, we are CUTTING AWAY + actually removing the blood from the vessel
is atherectomy common
not as common
-because higher risk of something going wrong
PTCA techniques
laser angioplasty
beam used to vaporize plaque into water + gas
-emits beam to remove plaque by turning it into a vapor
is laser angioplasty common
not as common
-because ability to target a very small area with a laser is very hard
after a PTCA procedure (balloon angioplasty, atherectomy, laser angioplasty), what do they do
put a bandaid over incision site
-typically outpatient so patient is in + out in 1 day
-femoral artery causes patient to be sore in groin area
PTCA indications
1-2 vessel involvement
EF ~ 55%
PTCA success
~85-90%
who would we suggest a PTCA for
individuals that don’t have incredibly advanced plaque, but rather maybe only 1 area
-their heart must be relatively healthy, which we determine via ejection fraction (EF around 55%)
why do we use EF as an indication for PTCA
because if they have a bad EF, using a stent won’t make a drastic difference
stent therapy- revascularization
reduces acute closure + restenosis of coronary arteries after PTCA
stent therapy- old method
bare metal stents + dual antiplatelet meds
stent therapy- new method
steel mesh- drug eluting stent + improved antiplatelet meds
-coated in antiplatelet medication that directly targets the plaque buildup from the stent itself
what did the new method of stent therapy do
provided improvements in endothelial hyperplasia
endothelial hyperplasia
scarring around stent leading to partial or full restenosis
-buildup of scar tissue within the endothelium
-further contributes to the narrowing of the vessel but nowhere near degree of plaque buildup
-still something we need to address
are stents a permanent fix
NO
-for most individuals they will work for around 2-3 years if they are adhering to medications + other instructions
-eventually the plaque will build up again + the stent will lose its effectiveness + we must go back in + remove the stent
-when you remove a stent, we INCREASE endothelial hyperplasia again
what happens when you remove a stent
increases endothelial hyperplasia
2 types of stents
-mesh/latticed
-coiled
the future of stent therapy
-stents from biodegradable polymer resins
-will reduce the threat of endothelial hyperplasia + also late stent thrombosis
-biodegradable stents would get rid of one of the aspects leading to endothelial hyperplasia since we wouldn’t have to go back in + remove it
-billions have been spent to try + create this but no luck yet
-CURRENTLY no biodegradable stents in the market
coronary artery bypass surgery (CABG)- revascularization
-uses venous graft from an arm or leg or an aterial graft
-creates bypass around damaged vessel
who is involved in a CABG
typically 1 cardiothoracic surgeon + another surgeon working somewhere else in the body to extract a vessel (aka graft)
where are vessels typically taken from in a CABG
-arm, leg, or mammary vessel
-we can use EITHER veins or arteriers
which vessels are BEST for a CABG
mammary vessels
-most resistant to atherosclerosis
CABG is reserved for which patients (4)
-unsuccessful PTCA
-patients who are no longer candidates for angioplasty but still have target vessels offering preservation of left ventricular systolic function
-multivessel disease no amenable to angioplasty or stenting
-technically difficult vessel lesions (ex: on the curve of a vessel or in a distal location not readily amenable to angioplasty or stenting)
what % of PTCAs are unsuccessful
10-15%
sternotomy
cutting down the middle of the sternum
benefit of sternotomy
provides full access to heart
right anterior thoracotomy
access to heart through one of the ribs
mini-sternotomy
only cutting top/bottom half of the sternum to gain access to the heart
when would a right anterior thoracotomy or mini-sternotomy be used
only if the surgeon is confident exactly where it is, how advanced, etc.
-most cardiothoracic surgeons will go with the full sternotomy in the case of if the condition was more advanced than they thought, it is better to have access to everything
protocol for CABG
-patient is given general anesthesia; ensures they will be asleep + pain free through the entire surgery
-surgeon makes 8-10 inch cut in the chest
-surgeon cuts through all or part of the patient’s breastbone to expose the heart
-once the heart is visible, the patient may be connected to a heart-lung bypass machine; the machine moves blood away from the heart so that the surgeon can operate; some newer procedures do not use this machine
-surgeon uses a healthy vein or artery to make a new path around the blocked artery
-surgeon closes breastbone with wire, leaving the wire inside the body; over time, the sternum will fuse back together
-the original cut is stitched up
how many surgeons working concurrently during CABG
2
is the heart stopped during CABG
yes- necessary because it will be hard for surgeon to work on the heart while it is actively beating
-they will shock the heart to make it stop + hook patient up to a heart-lung bypass to keep them alive while the heart is not actively beating
-this is how an individual can be in surgery for a long time without the rest of their tissue becoming necrotic
what securements are used in CABG to attach the vessel
staples + stitches
-these securements will become more permanent as these tissues fuse together
success rate of a revascularization procedure is predicted by which 3 things
-age
-other existing comorbidities
-severity + location of the lesion
as age increases, what does this mean for recovery
decreased chance at good recovery
how does severity + location of the lesion affect success rate
the bypass might not work due to increased severity
does everyone that needs a bypass get one
no
-due to risk factors + how invasive the procedure is
restenosis
reduction in the diameter of the vessel lumen after angioplasty
what is the #1 concern after bypass surgery
restenosis
(aka continued narrowing of the vessel)
how long do stents last
2-3 years
-because the antiplatelet drug wears off
predictors of restenosis after PTCA
-degree of residual stenosis after PTCA
-diameter of the parent vessel
-number of diseased vessels
-degree of reduction of the stenosis
-presence or type of coronary dissection
-presence of documented variant angina
-presence of comorbid disease (ex: diabetes, hyperlipidemia)
-optimal medical therapy + adherence
predictors of restenosis after stent
-lesion eccentricity
-diameter of the parent vessel
-type of vessel stented (artery vs. vein)
-location of stent in vessel
-presence of multiple stents
-recurrence of unstable angina
-presence of comorbid disease (ex: diabetes, hyperlipidemia)
-optimal medical therapy + adherence
lesion eccentricity definition
greater expansiveness of the lesion
-it goes further into depths of the vessel wall or farther length
LESION ECCENTRICITY IS A PREDICTOR OF RESTENOSIS IN STENTS
exercise prescription after these procedures
-mobilization in hospital ASAP
-cardiac rehab begins ASAP
-educational focus on medications, home activities, + follow-up appointments
after hospital discharge, what 3 things should exercise focus on
-improved cardiac performance at rest + during exercise
-improved exercise capacity (aerobic + strength)
-improved angina-free exercise tolerance, much of which is attributable to peripheral muscular adaptations
after hospital discharge, which type of exercise is the main focus
aerobic exercise
what is the primary concern after a PTCA
restenosis
ExRx special considerations after a PTCA
-assess for signs/symptoms indicative of angina
-initiate outpatient program as soon as they are discharged from the hospital or outpatient surgery facility
is cardiac rehab only prescribed for individuals that had surgery
no
-also for patients at risk of MI
ExRx special considerations after a CABG
-incisional healing
-sternal stability if open heart CABG
-soreness/stiffness in chest/back
-hypovolemia
-low hemoglobin concentrations
special considerations after a CABG- hypovolemia
blood volume loss post-surgery
(causes decreased cardiac output)
ExRx special considerations after a CABG- can exercise directly impact sternum
NO exercise should have direct impact on the sternum for these patients
ExRx special considerations after a CABG- everytime you breathe in…
puts pressure on your chest + causes pain
ExRx special considerations after a CABG- good movements to implement
shoulder circles/shoulders back to stretch the pec muscles
why do cardiac patients hunch over
because good posture pulls on chest muscles
hypovolemia leads to
-fatigue
-lightheadedness
special considerations after a CABG- low hemoglobin concentrations
caused from blood loss during surgery
