Therapeutic interventions (CMC) Flashcards
describe echocardiography, a cardiac diagnostic procedure
US waves to create images of heart allowing for evaluation of cardiac structures and function
describe cardiac catheterization, a cardiac diagnostic procedure.
what does it help identify?
catheter inserted into blood vessel and guided to the heart to measure pressures, obtain blood samples, or inject contrast dye for angiography.
-helps identify CAD, heart valve issues, congenital heart defects
all on one card bc it is our bread and butter
describe the diagnostic procedure of a right heart catherization
- how performed
- blood samples
- evaluates
- risk
1. used to assess
aka pulmonary artery catheterization.
used to assess the hemodynamics of the right side of the heart and pulmonary circulation. (specifically measure pressure in RA (CVP), RV (RVP), PA (PAP), and PCWP which reflects LA pressure.
involves the insertion of a catheter into a vein, typically IJ, subclavian, or femoral vein, and advancing it through the RA and RV into PA. typically local anesthesia with sedation. using fluoroscopic guidance to ensure placement.
blood samples can be obtained for oxygen saturation analysis to deterine the presence of shunts or to quantify cardiac output using thermodilution or Fick’s principle.
evaluates cardiac function (CO, vascular resistance, fluid status) and dx heart failure, pHTN, and congenital heart defects
risks: arrhthymias, bleeding at insertion site, infection, pneumothorax, PA rupture or thrombosis
describe the diagnostic procedure: left heart catheterization
used to dx and manage:
used to evaluate the function and strucutre of the left side of the heart, including the left atrium, left ventricle, aortic valve, and coronary arteries.
dx and manage cardiac conditions: CAD, valvular heart disease, cardiomyopathies
how is a left heart cath performed?
-pressure that are measured, what they show
-complications
-local anesthesia and fluoroscopic guidance
-artery is accessed (usually fem or radial), advanced into aorta and then LV
-typically involves angiography to visualize coronary arteries on xray using contrast dye (assess stenosis, occlusions, or abnormalities)
-LV pressure and CO can be measured (and other pressures); provide insight into aortic stenosis and mitral regurgitation
-left ventriculography: evaluates LV function, wall motion abnormalities, and ejection fraction
-complications: bleeding at access site, vascular injury, arrhythmias, or contract-induced nephropathy
primary goal of PCI
restore adequate blood flow to the heart by mechanically widening the obstructed artery, typically through balloon angioplasty, where small balloon is inflated at site of blockage, compressing the plaque against the arterial wall. Usually a stent is placed to keep artery open and prevent re-narrowing
what cardiac condition does a PCI treat/manage
CAD
describe PCI procedure
begins with cardiac cath, inserted into fem or radial artery, guided to coronary arteries under fluoro
-contrast day injected to visualize blockages via angiography
-interventional cardiologists decide on technique: simple balloon angioplasty or stent placement
types of stents for PCI
bare metal or drug eluding (DES)
drug eluding: coasted with medication that helps prevennt restenosis by inhibiting cell proliferation at the stent site.
factors to decide: risk of bleeding, likelihdoof of restonsis.
PCI risks
bleeding at cath site, arterial damage, kidney injury from constrast dye, heart attack or stroke.
long term: in-stent restonsis and stent thrombosis, needing dual antiplatelet therapy post procedure
what is a pericardiocentesis?
procedure involving aspiration of fluid form pericardial sac (double walled sac containing the heart). Primarily performed to relieve cardiac tamponade. The fluid’s characteristics can be tested to dx underlying conditions.
key indications for pericardiocentesis
and contraindications
hemodynamic instability due to cardiac tamponade, large symptomatic pericardial effusion, diagnostic evaluation of unexplained pericardial effusion,
contra: uncorrected coagulopathy, small effusions without clinical symptoms
complications from pericardiocentesis
myocardial puncture, coronary artery injury, arrythmias, infection
What is an IABP?
catheter-based device that is inserted into the aorta, typically through the femoral artery, to support cardiac function and improve myocardial oxygen delivery in patients with severe cardiac conditions. It has a long, thin tube with a balloon at its distal end.
the primary function is to augment diastolic blood pressure and decrease afterload, enhancing coronary perfusion and reducing myocardial oxygen demand.
How does the IABP work?
counterpulsation. during diastole, balloon inflates, increasing aortic pressure and improving blood flow to coronary arteries. occurs just after the closure of the aortic valve, optimizing coronary perfusion when the heart muscle itself receives its blood supply. during systole, the balloon deflates rapidly, creating a vacuum effect that decreases resistance in the aorta. the reduction in afterload makes ventricular ejection easier and decreases myocardial workload.
indications for IABP
contraindications
cardiogenic shock
acute MI with complications like MR or VSD
unstable angina refractory to medical therapy
bridge to PCI or surgery
hemodynamic support in high risk cardiac surgery patients
contraindications: severe PVD, aortic dissection
potential complications of IABP
limb ischemia
bleeding at insertion site
infection
balloon rupture
kidney injury
what is a LVAD?
mechanical pump that is surgically implanted to support heart function and blood flow in individuals with severe heart failure. It assists the LV by taking over its pumping action. it draws blood from the LV and delivers it directly into the aorta.
consists of several components: a pump implanted in the chest, external controller, and a power source (connect via driveline)
used as a bridge to transplantation, as destination therapy who are not heart transplant candidates, or as bridge to recovery in cases where myocardial function might improve.
anticoagulation therapy critical to minimize thromboembolic events due to non-pulsatile nature of most LVADs
describe TAVR (Transcatheter Aortic Valve Replacement)
common percutaneous intervention used to treat severe aortic stenosis. a bioprosthetic valve is delivered via a catheter through the femoral artery or another access point and deployed within the diseased aortic valve, replacing it without removing the old valve.
beneficial for those who are considered high risk for conventional surgery
describe the MitraClip procedure
for patients with MR who are not candidates for surgical repair or replacement. it is a device delivered through a transseptal approach the femoral vein to the left atrium where it clips together a portion of the mitral valve leaflets to reduce regurgitation
what is used to seal ASD and PFOs?
a septal occluder via a percutaneous catheter
what is peripheral angiography?
diagnostic procedure used to visualize the blood vessels outside of the heart to identify blockages or abnormalities in the peripheral arteries (which can lead to PAD). contrast dye is injected into the bloodstream and xrays are taken to provide detailed images of the blood vessels.
interventions following peripheral angiography
angioplasty: small balloon inserted and inflated at side of blockage to widen the vessel. most times a stent is placed to keep open
atherectomy- removing plaque from artery using rotating blade or laser. useful for calcified lesions resistant to balloon angioplasty alone.
complications of peripheral angiography and its interventions
bleeding, infection, allergic reaction to contrast dye, vessel damage or embolism
describe carotid angiography
diagnostic procedure used to visualize the carotid arteries, which supply blood to the brain. contrast dye is injected through a catheter into the carotid arteries, xrays are taken to reveal blockages or narrowing. used to assess presence and severity of carotid artery disease (often caused by atherosclerosis) which can lead to strokes.
interventions post carotid angiography
carotid endarterectomy (CEA): plaque removed from the arterial walls to restore normal blood. standard treatment for patients with significant stenosis, esp symptomatic or had TIAs or minor strokes.
carotid artery stenting (CAS): less invasive, small mesh tube (stent) is placed inside the artery to keep it open. often recommended to high risk surgery patients. balloon catheter expands the narrowed section of the artery before placing the stent.
both aim to prevent future strokes by improving cerebral blood flow
what is an endovascular graft?
aka endografts, medical devices used in minimally invasive treatment of vascular diseases, particularly aneurysms. designed to reinforce the weakened sections of blood vessels, most commonly within the aorta, by creating a new pathway for blood flow. crucial in preventing aneurysm rupture.
what is the procedure involving endovascular grafts?
endovascular aneurysm repair (EVAR). synthetic tube like graft is delivered to the site through catheter inserted via a small incision in femoral artery. graft is expanded and anchored in place using metallic stents, excluding aneurysm from circulation and reducing pressure on the weakened vessel wall.
size, location, vessel tortuosity and neck length are factors to consider
potential complications: graft migration or endoleaks (situations where blood leaks into aneurysm sac outside the graft)
What is a catheter-directed thrombolysis (CDT)?
minimally invasive procedure used to dissolve blood clots in the vascular system (DVT, PE). catheter is inserted into the clot allowing for localized delivery of thrombolytic agents like tissue plasminogen activator (tPA) which breaks down the fibrin matrix of the clot
catheter is navigated through vasculature until reaches site of clot. imaging techniques such as venography or angiography are used to confirm catheter placement and assess extent of thrombus. thrombolytic agent is then infused directly into the clot over a period ranging from several hours to days, depending on the size and location of the thrombus.
CDT advantages
reduced risk of bleeding complications and increased efficacy (higher local concentrations of thrombolytic drug). beneficial for those with extensive DVT or massive PE, where rapid clot resolution is necessary to restore venous patency and improve hemodynamics
CDT indications
contraindications
those with severe symptoms, contraindications to AC alone, or high risk for post-thrombotic syndrome
contra: active bleeding, recent surgery, significant coagulopathy
complications of CDT
rare but
bleeding at puncture site, hematoma formation
embolization of clot fragments
how many classes of antidysrhythmics are there?
four
- sodium channel blockers
- beta blockers
- potassium channel blockers
- calcium channel blockers
MOA of Class 1 antiarrhythmic
(sodium channel blockers) slow down depolarization phase of cardiac action potential by blocking sodium channels.
broken down into three subclasses
MOA Class 2 antiarrhythmic
Beta Blockers
reduce sympathetic nervous system stimulation of the heart by blocking beta-adrenergic receptors. this leads to decreased heart rate and contractility, which is useful in treating tachyarrhythmias.
metoprolol, atenolol
3 subclasses of antiarrhythmics
Class 1A: moderate sodium channel blockers, prolonging repolarization (Quinidine, Procainamide)
Class 1B: weak sodium channel blockage, shortening repolarization. (Lidocaine, Mexiletine)
Class 1C: strong sodium channel blockade with minimal effect on repolarization (Flexainide, Propafenone)
MOA Class 3 antiarrhythmics
potassium channel blockers
prolong repolarization by blocking potassium channels, extending the refractory period of cardiac cells. Effective in treating both atrial and ventricular dysrhythmias.
amiodarone and sotalol
MOA Class 4 antiarrhythmics
calcium channel blockers
inhibit calcium ion influx through L-type calcium channels, primarily affecting AV node conduction and reducing heart rate
Verapamil and diltiazem commonly used for rate control afib.
two main types of anticoagulants
oral and parenteral
oral AC examples and MOA
- vitamin K antagonists (warfarin)
-DOACs (dabigatran, rivaroxaban, apixaban, endoxaban)
how does warfarin work?
inhibits vitamin K epoxide reductase, an enzyme necessary for the synthesis of clotting factors II, VII, IX, and X
how do DOACs work?
directly on specific factors within the coagulation cascade
ex: dabigatran inhibits thrombin (factor IIa)
Rivaroxaban, apixaban, edoxaban inhibit factor Xa.
parenteral AC examples
UFH
LMWHs Iike enoxaparin)
fondaparinux
how does unfractionated heparin work (UFH)?
enhances the activity of antithrombin III, which inactivates thrombin and factor Xa.
how does LMWH work?
primarily inhibit factor Xa, with some effect on thrombin
how does fondaparinux work?
it is a synthetic pentasaccharide that specifically inhibits factor Xa
3 types of diuretics
based on site of action in the nephron
-thiazide diuretics
-loop diuretics
-potassium sparing diretics
how do thiazide diretics work?
on distal convoluted tubule to inhibit sodium reabsorption, leading to increased excretion of sodium and water
commonly used for long term management of HTN
hydrochlorothiazide
how do loop diuretics work?
target ascending limb of loop of Henle. inhibit sodium-potassium-chloride co-transporter, resulting in significant diuresis.
open used for rapid fluid removal in heart failure or pulmonary edema
furosemide, bumetanide
how do potassium sparing diuretics work?
work on collecting ducts and distal tubules to prevent potassium loss while promoting sodium excretion
beneficial for those at risk of hypokalemia or those requiring aldosterone antagonism.
spironolactone and eplerenone
why monitor renal function while pt on diuretics?
can decrease kidney perfusion
categories of inotropes
positive and negative, based on effects on myocardial contractility
how do positive inotropes work?
increase strength of heart’s contractions, enhancing CO. by increasing intracellular calcium concentrations, which are essential for muscle contraction.
common: dobutamine, dopamine, milrinone
how does dobutamine work?
primarily stimulates B1- adrenergic receptors, leading to increased myocardial contractility with minimal effects on heart rate
how does dopamine work?
dose dependent
moderate doses: stimulates B1 receptors to enhance CO
higher: also acts on alpha-adrenergic receptors, causing vasoconstriction
how does milrinone work?
phosphodiesterase inhibitor that increases cyclic adenosine monophosphate (cAMP) levels, leading to enhanced calcium influx and stronger myocardial contractions
how do negative inotropes work?
decrease myocardial contractility and often used to reduce cardiac workload in conditions such as hypertrophic cardiomyopathy or certain forms of angina
ex: BB like metop and CCB like verapamil
considerations for inotropes
prolonged use can lead to
-increased myocardial oxygen demand
-potential for arrythmias
primary MOA of platelet inhibitors in the most basic sense
blocking specific pathways that active platelets
how does aspirin work?
irreversibly inhibits the cyclooxygenase-1 (COX 1) enzyme in platelets. this prevents the formation of thromboxane A2, a potent promoter of platelet aggregation and vasoconstriction
how do P2Y12 receptor antagonists work?
block P2Y12 component of the ADP receptor on the platelet surface, preventing ADP-mediated activation and aggregation of platelets
ex: clopidrogrel, prasugrel, ticagrelor