Cardiology Flashcards
Adult Congenital Heart Disease (CHD)
Anesthetic Considerations
Goals & Conflicts
Adult Congenital Heart Disease (CHD)
Anesthetic Considerations
Long term consequences of CHD:
Cardiac: pulmonary hypertension, heart failure, arrhythmias, residual shunts, valvular lesions
Non-cardiac: erythrocytosis, cholelithiasis/nephrolithiasis, developmental abnormalities, seizure disorder, CVA, chronic lung disease
Endocarditis prophylaxis
Management of medications, especially anticoagulants
Lesion-specific anesthetic goals & management
↑ perioperative risk requiring multidisciplinary care
Goals & Conflicts
Preoperative assessment of cardiac & non-cardiac complications
Considerations of surgical stress & positioning
Lesion-specific hemodynamic goals with focus on PVR, SVR, preload, contractility, HR
Need for invasive monitoring including arterial line & central line placement
De-airing of lines
Aortic Dissection
Considerations
Type
End organ damage
Causes
Anesthetic Management
What to avoid
Pregnancy Considerations
Aortic Dissection
Considerations
Type & urgency:
Stanford type A: Surgical management
Stanford type B: Medical management or stent only if organ damage or complicated aortic dissection
End organ damage & ischemia
Stanford type A associated with aortic insufficiency, tamponade, MI, CVA
Acute renal failure
Spinal cord ischemia
Ischemic gut
Limb ischemia
Hemorrhagic shock
Pleural effusions
Retroperitoneal bleeding
Underlying cause of aortic dissection
Trauma
Hypertension, atherosclerosis
Cocaine/amphetamine use
Pregnancy
Collagen vascular disease (e.g. Marfan’s)
Anesthetic Management
Medical stabilization:
IV access, CVC, arterial line (R arm AND L arm or femoral)
Hemodynamic goals
Preload: maintain adequate preload; aggressive fluid therapy may worsen dissection
Rate: heart rate <60bpm with beta blockade
Rhythm: maintain normal sinus rhythm
Contractility: reduce contractility with beta blockade to reduce sheer stress on intima
Afterload: reduce sBP to a target of 100-120 mmHg to reduce sheer stress on intima
Main goal is to ↓ cardiac contractility & BP to ↓ intimal stress
1st line therapy is beta blockade to achieve hemodynamic goals
Labetalol (bolus 20-80mg then infusion 0.5-2mg/min)
Esmolol (bolus 0.5-1 mg/kg then infusion 50-200 mcg/kg/min)
Consider diltiazem (2.5-5mg IV q15min) & verapamil (2.5-5mg IV q15min) in patients intolerant of beta blockers
Consider adding sodium nitroprusside (0.25-0.5mcg/kg/min) to achieve sBP of 100-120mmHg
Adequate pain control
Things to avoid:
Inotropes
Hydralazine, which can cause aortic wall sheer stress
Vasodilation before beta blockade, which can cause reflex sympathetic activation
Pericardiocentesis in tamponade, which can cause exsanguination
Pregnancy Considerations
Aggressive alpha & beta-blockade to ↓ dP/dT as above
Continuous fetal heart rate monitoring (marker of end organ perfusion)
Type B:
Medical management & expedite delivery
Use short acting agents (esmolol, labetalol, phentolamine)
Conflicts:
Antihypertensives vs. bleeding risk/post partum hemorrhage (eg. nitroglycerine & ↓ uterine tone)
Avoid fetal toxic medications (sodium nitroprusside)
Avoid ergotamine for post partum hemorrhage
Type A:
If diagnosed <28 weeks = surgical repair, then allow pregnancy to continue
28-32 weeks = surgical repair, cesarean section if obstetrical indications
> 32 weeks = simultaneous repair & cesarean section
Aortic Regurgitation
Considerations
Hemodynamic goals
Management of severe acute aortic regurgitation
Aortic Regurgitation
Considerations
↑ risk of perioperative cardiovascular decompensation
Hemodynamic sequelae of aortic regurgitation:
Left atrial (LA) distension/volume overload & subendothelial ischemia
LA dilation & eccentric hypertrophy, potential for ischemia & arrhythmias
CHF & pulmonary edema
RVF & pulmonary HTN
Acute aortic regurgitation:
Sudden increase in LV volume, cardiogenic shock & pulmonary edema
↑ sympathetic drive
Comorbid disease:
Aortic arch dilation (Marfan’s, dissection, infection, ankylosing spondilitis)
Valvulopathy (aortic stenosis, infective endocarditis, SLE)
Ischemic heart disease
Management of medical therapy (diuretics, anticoagulants)
Hemodynamic goals
Key is to maintain forward flow & ↓ regurgitant volume
Preload: normal to high to augment cardiac output
Rate: high normal
Rhythm: sinus if possible, but rate is more important
Contractility: maintain or augment
Afterload: keep afterload low to promote forward flow
Management of severe acute aortic regurgitation
Sudden aortic incompetence does not allow time for compensatory LV dilation & results in acute pulmonary congestion
Immediate management involves afterload reduction (nitroprusside) & augmentation of contractility & rate (dobutamine)
Likely needs emergency aortic valve replacement/repair
Intra-aortic balloon pump is CONTRAINDICATED
Aortic Stenosis
Anesthetic Considerations
Anesthetic Goals
Aortic Stenosis
Anesthetic Considerations
Identify severity of disease & high risk markers (angina, syncope, CHF)
↑ risk of perioperative cardiovascular complications (MI, CHF, arrhythmias)
Hemodynamic consequences:
Fixed LVOT obstruction with limited ability to ↑ cardiac output
Hypertrophied ventricle with diastolic dysfunction
Altered myocardial oxygen supply/demand
Systolic dysfunction late in disease
Associated complications:
Coronary artery disease (CAD): 50% of patients with angina have concomitant CAD
Other valvular disease
Pulmonary hypertension
Sudden cardiac death/malignant arrhythmia
Potentially ineffective CPR
Anemia/bleeding risk:
Acquired von Willebrand syndrome
Mucosal/GI angiodysplasias
Always consider valvuloplasty/cardiology & cardiac surgery consult prior to semi-urgent/elective procedures
Management of medications
Anesthetic Goals
Preload: maintain adequate intravascular volume to fill non-compliant ventricular chamber (sensitive to volume depletion)
Rate: low normal (maximize diastolic filling & coronary perfusion)
Rhythm: sinus (atrial kick contributes up to 40% of total cardiac output)
Contractility: maintain (prone to subendocardial ischemia (↑ muscle mass, ↓ coronary perfusion pressure)
Afterload: maintain (coronary perfusion pressure)
Severity Scale
Atrial Fibrillation
Considerations
Etiology
Complications
Management
Optimization/Goals
Scoring System
Atrial Fibrillation
Considerations
↑ risk perioperative cardiac complications
Etiology:
Structural/valvular heart disease
Other secondary causes: Alcoholism, electrolyte imbalance, hyperthyroidism, infection, etc
Complications of atrial fibrillation:
CHF, tachycardia-induced cardiomyopathy
Embolic events & stroke risk
Medication management:
Rate control & rhythm control (beta blockers, calcium channel blockers, digoxin, amiodarone)
Anticoagulation: Bridge for those with CHADS2≥4 in consultation with hematology
Optimization/Goals
ACLS approach, cardiovert if unstable
Elective cases:
if HR < 110, no CHF: proceed with OR, may need ASA depending on CHADS2
If CHF or HR > 110: needs optimization in consultation with cardiology, internal medicine, or patient’s GP
Fix underlying electrolyte abnormalities
Rate control in sick patients:
Amiodarone
Digoxin in LV dysfunction: 0.25-0.5mg IV initial dose, follow ECGs
Emergency cases: ↑ risk if HR > 110 or CHF
Consider cardiology consult/monitored bed
Octaplex or FFP or Vit K for emergent INR reversal
Atrial Septal Defect (ASD)
Considerations
Goals
Pregnancy Considerations
Atrial Septal Defect (ASD)
Considerations
Etiology & severity of ASD: Size, shunt (L→R / R→L)
Complications of chronic L to R shunt:
Arrhythmias (atrial fibrillation & supraventricular tachycardias)
Pulmonary HTN, RV dysfunction, shunt reversal (R→L with hypoxemia)
Tricuspid valve & pulmonic valve disease
↑ perioperative risk of:
Arrhythmia, pulmonary hypertension crisis, RV dysfunction/failure
R→L shunt reversal: hypoxemia, paradoxical air embolism
Paradoxical embolism (air, CO2, septic, thrombus)
Comorbid disease:
Adult congenital heart disease, Down syndrome, etc
Previous closures
Medications: anticoagulation, antiarrhythmics
Considerations for closure of ASD:
Out of OR considerations
Complications (tamponade, arrhythmias, valve disruption, & emboli)
Goals
Hemodynamic goals:
Preload: maintain adequate preload
Rate: maintain normal rate
Rhythm: maintain normal sinus rhythm
Contractility: maintain adequate contractility
Afterload: avoid extremes of systemic vascular resistance; ↑ SVR may precipitate pulmonary hypertension & RV dysfunction, ↓ SVR may cause R→L shunting & hypoxemia
De-air lines (risk of pulmonary air embolism)
Pregnancy Considerations
Pregnancy is well-tolerated if pulmonary hypertension not present
Control of SVR critical to limiting bidirectional shunting
Labour: early titrated epidural preferred
For epidural, do NOT use loss of resistance to air (use saline)
C-section: give anesthetic by titrated epidural
Brugada Syndrome
Background
Anaesthetic Considerations
Typical ECG Findings
Brugada Syndrome
Background
Brugada syndrome is a rare autosomal dominant disease & is associated with sudden cardiac death from ventricular fibrillation or tachycardia (VT/VF), especially in Southeast Asian males
Anesthetic Considerations
Potential for hemodynamic collapse due to VT & VF
Avoid exacerbating factors of Brugada (ST Elevation):
Parasympathetic nervous system stimulation (increase in vagal tone)
Medications
Avoid BB, alpha agonists, neostigmine
Avoid class Ia antiarrhythmic (procainamide)
Electrolyte abnormalities: ↑↓K, ↑Ca
Fever
Considerations of AICD if in situ (only known treatment)
Preparations for treating Brugada Exacerbations or cardiac arrest:
All patients without AICD need defibrillator & pads in OR
Atropine, Ephedrine, Isoproterenol
Resuscitation drugs should be available
Cardiac Contusion
Considerations
Complications
Early
Late
Conflicts
Optimization/Goals
Cardiac Contusion
Considerations
Trauma patient & need for ATLS approach, other occult injuries
Potential emergency with arrhythmias, cardiogenic shock
Complications
Early: arrhythmias, myocardial rupture, valvular damage, thrombosis
Late: ventricular aneurysm, dilated cardiomyopathy, pericarditis, ventricular arrhythmias
Conflicts
Hemodynamic instability vs. rapid sequence intubation in trauma setting
Hemodynamic instability vs. operative management of other significant injuries
Optimization/Goals
Determine extent of myocardial injury (troponin, ECG, echo)
Admit to ICU for monitoring
Use invasive monitoring as appropriate
Manage cardiogenic shock: invasive monitoring, fluid resuscitation, inotropes/pressors, intra-aortic balloon pump
Cardiac Tamponade
Considerations
Goals
Cardiac Tamponade
Considerations
Emergency with potential for cardiovascular collapse on induction
Pathophysiologic changes:
Impaired diastolic filling
Fixed stroke volume
Rate-dependent cardiac output
Hemodynamic goals:
Full, fast, maintain contractility, maintain SVR
Etiologies/co-existing diseases:
Blood: post-cardiac surgery, post-MI, aortic dissection, trauma
Other: infectious, malignant, radiation, SLE, uremia, autoimmune, pericarditis
Goals
If hemodynamically significant, drain prior to general anesthesia & positive pressure ventilation (PPV)
Spontaneous respiration & avoidance of PPV, coughing, straining
Cardiovascular goals: fast, full and tight
Preload: full
Contractility: maintain, avoid myocardial depressants
Rate: maintain, possibly ↑
Rhythm: strict NSR
Systemic vascular resistance: maintain or ↑
Cardiomyopathies
Considerations
Etiologies
Cardiomyopathies
Considerations
↑ risk of perioperative hemodynamic compromise:
CHF, dysrhythmias, emboli, myocardial ischemia
Type, etiology & severity of cardiomyopathy:
Dilated, restrictive, hypertrophic, peripartum
Presence of CHF including EF, NYHA class
Assess volume status & sympathetic activation
Hemodynamic goals specific to type of cardiomyopathy:
Restrictive (diastolic failure):
Goals: fast, full & tight (as per tamponade)
Contractility: maintain
Rate & rhythm: sinus (atrial kick important), avoid bradycardia (SV relatively fixed)
Afterload: maintain (coronary perfusion with ↑ LVEDP)
Preload: maintain normovolemia (but avoid ↑ LVEDP)
Dilated (systolic failure):
Contractility: Maintain
Rate & rhythm: NSR
Afterload: maintain, may benefit from ↓
Preload: normal HR, avoid ↑ afterload
HOCM:
Contractility: ↓
Rate & rhythm: strict NSR, avoid tachycardia
Afterload: maintain
Preload: full
AICD/pacemaker considerations if applicable
Comorbid disease including possible systemic implications of etiology (eg. infiltrative disease)
Medication management: beta blockers, ACEI, anticoagulation, diuretics
Coronary Artery Disease
Consideration
Goals
Potential conflicts
Minimum antiplatelet duration
Coronary Artery Disease
Considerations
↑ risk of perioperative cardiovascular complications: MI, CHF, arrhythmias, death
↓ cardiovascular reserve & need to optimize myocardial oxygen supply & demand
Comorbidities: HTN, stroke, renal dysfunction, peripheral vascular disease, diabetes, smoking
Management of coronary stents
Associated medications: antihypertensives, anticoagulants, diuretics
Goals
Optimize myocardial oxygen supply & demand
Preload: keep the heart small to ↓ wall tension/LVEDP & ↑ coronary perfusion pressure gradient
Rate & rhythm: slow, normal sinus rhythm
Contractility: maintain
Afterload: maintain, coronary perfusion dependent on diastolic pressure
Potential conflicts
Full stomach vs need for titrated induction
Need for surgery vs antiplatelets for coronary stents
Minimum antiplatelet therapy duration
Balloon angioplasty: 2 weeks
Bare metal stent: 1 month
Drug eluting stent: 1 year (but could be less; guidelines are evolving)
Hypertrophic Obstructive Cardiomyopathy (HOCM)
Considerations
Goals
Pregnancy
AF and HOCM
Hypertrophic Obstructive Cardiomyopathy (HOCM)
Considerations
Dynamic LVOT obstruction (20-30% of patients) & need to avoid precipitants
Perioperative hemodynamic complications:
Arrhythmia
Ischemia & diastolic dysfunction
Secondary hypertrophy
MR
End stage: dilated cardiomyopathy
Medication management:
Beta blockers & calcium channel blockers
Antiarrhythmics
Anticoagulants
Diuretics
Pacemaker/ AICD
Goals
Preload: maintain preload
Rate & rhythm: slow-normal rate; maintain sinus rhythm
Contractility: ↓ contractility
Afterload: maintain or ↑ afterload
Pregnancy
Usually tolerated well
Continue beta blockers in pregnancy
Goals:
Maintenance of intravascular volume & venous return
Avoidance of aortocaval compression
Maintenance of adequate SVR
Maintenance of a slow heart rate in sinus rhythm
Aggressive treatment of acute atrial fibrillation & other tachyarrhythmias
Prevention of increases in myocardial contractility
Anesthetic technique:
Likely need extra monitoring: arterial line, 5 lead ECG, possible CVC, tertiary/cardiac centre
Spinal relatively contraindicated because of the rapid onset of a sympathectomy
Epidural for elective cesarean section well tolerated
GA also well tolerated
They tolerate 2nd stage of labor well as ↑SVR helps HOCM, could consider assisted 2nd stage if needed
Postpartum hemorrhage: oxytocin OK if given slowly; ergot a great agent
Atrial Fibrillation in HOCM Patient
Acute in OR, best measure is cardioversion
Beta blockers also very good choice (e.g. esmolol infusion)
Infective Endocarditis (IE) Prophylaxis
Indications (AHA 2007)
Eligible Operative Procedures
Antibiotic regimens
Infective Endocarditis (IE) Prophylaxis
Indications (AHA 2007)
Prosthetic valve
Previous IE
Congenital heart disease, specifically:
Unrepaired cyanotic heart disease, including palliative shunts & conduits
Congenital heart disease repaired within the last 6 months
Repaired but residual defects next to prosthetic material
Heart transplant recipients with valvulopathy
Eligible Operative Procedures
Dental procedures with mucosal penetration
Procedures involving respiratory tract incision (including bronchial biopsy)
Procedures involving infected skin/musculoskeletal tissue
Antibiotic regimens
One dose 30-60 min prior to the procedure
Recommended agent is amoxicillin
2g PO for adults
50mg/kg PO for children
Keflex
2g PO for adults
50mg/kg PO for children
Ampicillin
2g IV for adults
50mg/kg IV for children
Cefazolin or ceftriaxone
1g IV for adults
50mg/kg IV for children
Clindamycin
600mg IV for adults
20mg/kg IV for children
Azithromycin or clarithromycin
500mg PO for adults
15mg/kg PO for children
Mitral Regurgitation (MR)
Considerations
Goals
Pregnancy Considerations
Goals
Monitoring
Anaesthetic options
Mitral Regurgitation (MR)
Considerations
↑ risk of perioperative cardiac complications (MI/CHF)
Hemodynamic alterations associated with MR:
Left atrial volume overload & ↓ forward cardiac output (CO)
Potential for LV dysfunction (from overload)
Potential for arrhythmias (atrial fibrillation commonly) due to LA dilatation
Potential for pulmonary hypertension leading to RV dysfunction
Acute MR: sudden LA & LV overload without compensatory hypertrophy leading to decreased forward CO & simultaneous pulmonary congestion
Comorbid disease:
Coronary artery disease
Atrial fibrillation
Other valvular lesions (MS, AI)
Connective tissue diseases (SLE, RA, Marfan’s)
Endocarditis
Management of medical therapy:
ACE inhibitors, beta-blockers, digoxin, calcium channel blockers
Goals
Maintain forward flow & ↓ regurgitant fraction:
Preload: maintain preload but avoid overload (↑ risk for CHF)
Rate: high-normal rate (80-100bpm) & avoid bradycardia (longer diastole = more regurgitation)
Rhythm: sinus rhythm preferred but not as critical as stenotic lesions
Contractility: maintain or enhance contractility to improve forward flow & reduce regurgitant fraction by constricting mitral valve annulus
Afterload: reduce afterload to enhance forward flow
Avoid ↑ in pulmonary vascular resistance to mitigate right heart failure (avoid hypoxia, hypercarbia, acidosis, pain)
Pregnancy Considerations
Goals:
Prevent an ↑ in SVR
Maintain a normal to slightly elevated heart rate
Maintain sinus rhythm
Aggressively treat acute atrial fibrillation
Avoid aortocaval compression
Maintain venous return
Prevent an ↑ in central vascular volume
Avoid myocardial depression during general anesthesia
Prevent pain, hypoxemia, hypercarbia, & acidosis (may ↑ PVR)
Monitoring:
Invasive monitoring rarely required unless severe mitral regurgitation
Anesthetic options:
Epidural preferred for vaginal delivery or cesarean section
If GA used, give attention to the maintenance of adequate heart rate & ↓ afterload
Acute atrial fibrillation must be treated promptly & aggressively; hemodynamic instability warrants the immediate performance of cardioversion
Mitral Stenosis (MS)
Considerations
Goals
Pregnancy Consideration
Goals
Risk
Anaesthetic options
Mitral Stenosis (MS)
Considerations
Perioperative cardiovascular decompensation:
Severity of valvular lesion
High risk (especially with pregnancy)
Hemodynamic sequelae of MS (limited ability to ↑ cardiac output)
Atrial dilation & arrhythmias
Pulmonary edema & CHF
Pulmonary hypertension & RV failure
Thrombotic events
Associated conditions:
Associated valvular pathologies
Rheumatic heart disease
Connective tissue disease (SLE, RA)
Obstructive (carcinoid, atrial myxoma)
Medications:
Anticoagulation (often need bridging with heparin)
Diuretics
Antiarrhythmics
Goals
Preload: maintain (avoid overload)
Rate: low-normal (most important goal)
Rhythm: sinus (avoid atrial fibrillation because of ↑ HR)
Contractility: maintain
Afterload: maintain
Avoid precipitants of pulmonary hypertension
Severity Grading
Pregnancy Considerations
Goals:
Maintain a slow heart rate
Maintain sinus rhythm
Aggressively treat acute atrial fibrillation
Avoid aortocaval compression
Maintain venous return
Maintain adequate systemic vascular resistance
Prevent pain, hypoxemia, hypercarbia, and acidosis (may ↑ pulmonary vascular resistance)
Risk:
Mild to moderate MS without severe pulmonary HTN is considered low maternal or fetal risk
Mitral stenosis with NYHA class II-IV symptoms is considered high maternal risk
Anesthetic options:
Vaginal delivery
Symptomatic patients will require invasive monitoring
Adequate analgesia for first stage (epidural)
Second stage should be assisted by low forceps/vacuum
Cesarean section
Epidural is the preferred method
If GA required need to keep goals
Pacemakers & ICDs
Considerations
Goals
Causes of intra-operative failure
Insertion complications
Pacemakers & ICDs
Considerations
Indications for the device:
Pacemaker: SA node disease, AV block, CRTD, MI, HOCM, dilated cardiomyopathy
AICD: VT, VF, cardiomyopathy with EF<35%
Determine dependency & history of use
Strategies to minimize risk & prepare for potential PM/AICD interference & failure:
Strategies to minimize EMI (electromagnetic interference):
Bipolar cautery
Short bursts of cautery (<5sec), distance, “cut” better than “coag” or “blend”
Have magnet available
Device interrogation pre & post op:
Reprogram to asynchronous (pacemaker) or disable anti-tachycardia therapy (ICD)
Alternate pacing/defibrillation strategies:
Sympathomimetics (epinephrine, dopamine, isoproterenol)
Transvenous/transcutaneous pacing
External defibrillator device
Co-existing Disease:
Associated CAD, cardiomyopathy with low EF
Hypertension, renal failure, diabetes
Perioperative medication management
Goals
Optimization of underlying cardiac status
Knowledge of device settings & response to magnet
Anticipate & prevent failure or interference with appropriate backups
Avoid inappropriate inhibition (asystole) or triggering of device (shocks) by EMI
Prevent damage to device
Causes of Intra-operative Pacemaker Failure
Generator failure (e.g. battery, malfunction)
Lead failure (e.g. dislodgement)
Failure to capture
Acid-base imbalance
Electrolyte abnormality
Ischemia/infarction
Antiarrhytmics (overdose or withdrawal)
Pacemaker Insertion Complications
Pneumothorax
Arterial puncture
Arrhythmia
Venous air embolism
Cardiac perforation/tamponade
QT Prolongation
Considerations
Goals
Definitions
Treatment
QT Prolongation
Considerations
Potential for hemodynamic collapse secondary to rapid polymorphic VT & VF
Avoid triggers of Torsades de Pointes: sympathetic stimulation, medications, electrolyte disturbances (↓K, ↓Mg, ↓Ca)
Congenital long QT: may have pacemaker/AICD, perioperative β-blockade; avoid sympathomimetics
Goals
Avoid triggers of Torsades:
SNS stimulation (pain, nausea, emotional stress, loud noise)
Bradycardia, tachycardia, hypertension, hypoxemia, hypercapnia
Electrolyte disturbances: ↓K, ↓Mg, ↓Ca
QT prolonging medications: antiemetics, antipsychotics, amiodarone, methadone
Congenital long QT: avoid beta-agonists, ketamine
Continue beta blockade for congenital long QT; ensure optimal AICD function if applicable
Preparations for treating Torsades: defibrillator & pads in OR, MgSO4, resuscitation drugs
Various Definitions for Prolonged QTc
QTc > 470 ms (males) to > 480 ms (females) (Anesthesiolgy, 2005)
> 460 ms (Stoelting Co-existing 6th Ed)
> 460 regardless of age (Cote 4th Ed)
> 470 ms (males) & >480 ms (females) (AHA/ACC Consensus statement 2011)
Treatment of Torsades
Defibrillation & CPR as per ACLS
Magnesium 2g IV over 2 min (30 mg/kg), q15min x 3; pediatrics 25-50mg/kg bolus
Overdrive pacing to 90-110 with transvenous pacemaker
Isoproterenol to ↑ HR 90-100
↑ K to 4.5
Stop QT prolonging medications: antipsychotics, antiemetics antibiotics, antifungals, antidysrhythmics, antidepressants, antihistamines, antineoplastics
Transplanted Heart
Considerations
Goals
Pregnancy Considerations
Transplanted Heart
Considerations
Altered physiology of the denervated heart:
Preload dependent
High resting heart rate & loss of vagal tone
Delayed sympathetic response to circulating catecholamines
Dysrhythmias & conduction abnormalities → permanent pacemaker in 5%
Altered pharmacology of the transplanted heart:
Ineffective indirect-acting agents (e.g. ephedrine, atropine)
Intact response to direct-acting vasoactive drugs (e.g. epinephrine, isoproterenol)
Allograft function:
Rejection
Arrythmias
Coronary vasculopathy (accelerated CAD): silent ischemia secondary to denervation
Co-morbidities:
Hypertension (90%)
Diabetes
Renal dysfunction
Malignancy
Steroid therapy: will require stress dose
Immunosuppressive therapy:
↑ risk of infection & need for strict sterile technique
Adverse effects: anemia, thrombocytopenia, hepatotoxicity, nephrotoxicity
Goals
Hemodynamic goals:
Preload: maintain normal or high (CO increases by increasing stroke volume)
Rhythm: avoid pro-arrhythmic states
Afterload: maintain perfusion to potentially ischemic myocardium
Use direct-acting sympathomimetics (isoproterenol & epinephrine must be available)
Avoid infection: strict sterile technique & minimize catheters/invasive devices
Thorough review of functional capacity, investigations (echo, biopsies for graft dysfunction)
Strongly consider consultation with transplant clinic & cardiology pre-operatively
If valvulopathy: needs infective endocarditis prophylaxis
Pregnancy Considerations
Same goals as above apply
Epidural is very good technique
Ensure adequate intravascular volume
Extra attention to aseptic techniques
Tricuspid Regurgitation
Consideration
Anaesthetic goals
Tricuspid Regurgitation (TR)
Considerations
↑ risk of perioperative cardiovascular complications
Hemodynamic consequences:
Mild-moderate usually well tolerated with little consequence
Severe TR may result in RV pressure/volume overload ➝ RV dysfunction, hepatomegaly, ascites, peripheral edema, cardiorenal syndrome
Medication management
Management of any comorbid diseases (e.g. pulmonary hypertension, endocarditis, carcinoid, rheumatic heart disease)
Anesthetic Goals
Preload: normal to ↑, critical to avoid hypovolemia
Rate: normal to high to sustain forward flow
Rhythm: sinus
Contractility: RV may need inotropic support if RV failure
Afterload: maintain
PVR: avoid any ↑ (avoid high airway pressures, hypercarbia, hypoxemia, hypothermia, acidosis)
Wolff-Parkinson-White Syndrome
Anesthetic Considerations
Goals
Arrhythmia Treatments
ECG features
Wolff-Parkinson-White Syndrome
Anesthetic Considerations
Potential for perioperative SVT or atrial fibrillation:
Consider crash cart, defbrillator pads, invasive arterial access, emergency drugs (procainamide, amiodarone)
Avoid AV nodal blockers if atrial fibrillation
Avoid sympathetic stimulation: pain, anxiety, hypovolemia, ketamine
Goals
Identify patients with WPW
Minimize sympathetic stimulation & drugs (adenosine, beta blockers, calcium channel blockers, digoxin) that could enhance anterograde conduction of cardiac impulses through the accessory pathways
Reduce anxiety which may precipitate tachycardia
Arrhythmia Treatments
Acute termination of orthodromic AVRT (approach is same as the usual patient with SVT):
1st line: vagal maneouvers, verapamil (5mg IV q3min up to 15mg), adenosine (6-12mg IV bolus with flush)
2nd line: procainamide, beta blockers, digoxin, amiodarone (prolongs the refractoriness of all cardiac tissues)
Acute termination of antidromic AVRT:
If unstable, must cardiovert
Avoid AV nodal blocking agents
If stable: IV drug of choice for acute treatment to terminate known antidromic AVRT is procainamide.
Procainamide is typically infused intravenously at 20 to 50 mg/minute given while monitoring the blood pressure closely every 5 to 10 minutes until the arrhythmia terminates, hypotension ensues, the QRS is prolonged by more than 50 percent, or a total of 17 mg/kg (1.2 g for a 70 kg patient) has been given
Acute termination of atrial fibrillation with pre-excitation:
AV nodal blocking drugs (adenosine, verapamil, beta blockers, & digoxin) should be avoided in patients with preexcited atrial fibrillation since blocking the AV node will promote conduction down the accessory pathway & may sometimes directly enhance the rate of conduction over the accessory pathway
The goals of acute drug therapy for preexcited AF are prompt control of the ventricular response & ideally, termination of atrial fibrillation
If unstable, must cardiovert
If stable, careful trial of IV drugs (no clear 1st line drug):
Procainamide (Class IA): 20-50mg/min until arrhythmia suppressed, hypotension ensues, QRS prolonged by 50% of original duration or total fo 17mg/kg has been given
Amiodarone (Class III): first dose 150mg over 10min, then 1mg/min for 6hrs, then 0.5mg/min for 18hrs
Ibutilide (Class III): if patient <60kg, 0.01mg/kg over 10min; if >60kg, 1mg over 10min
ECG Features
Short PR, wide QRS, delta wave
Pulmonary Hypertension
Considerations
Goals
Pulmonary Hypertension
Considerations
Potential for acute perioperative right ventricular (RV) dysfunction & hemodynamic collapse
Optimize pulmonary pressures & right heart function:
Avoid hypoxia, hypercarbia, acidosis, hypothermia, sympathetic stimulation (pain), high PEEP
Cautious fluid administration
Maintain RV perfusion
Associated conditions (see table below)
Medication management:
Anticoagulation
Calcium channel blockers
Vasodilators (e.g. sildenafil)
Prostacyclin analogs (e.g. epoprostenol/flolan)
Endothelin antagonists (e.g. bosantan)
Diuretics
Need for invasive monitoring, optimized analgesia & post-op disposition
Potential or R → L shunt through PFO: hypoxemia & paradoxical emboli
Goals
Make all attempts to optimize pulmonary vascular resistance (PVR) before surgery
Avoid ↑ in PVR (minimize pain, sympathetic stimulation, hypoxia, hypercarbia, acidosis, optimize airway pressures)
RV failure management principles:
Optimize RV rate & rhythm: sinus & normal-high rate
Optimize RV filing
Maintain RV perfusion & inotropy
↓ PVR
Conflicts
Pulmonary hypertension & laparoscopy:
↑ PaCO2, sympathetic stimulation = bad
Case is longer than open
Ortho cases with cement, joint replacement (embolic risk)
Hemodynamic stability vs need for RSI
Pregnancy Considerations
Hemodynamic goals:
Prevent ↑ PVR
Maintain intravascular volume & venous return
Avoid aortocaval compression
Maintain adequate systemic vascular resistance
Avoidance of myocardial depression during general anesthesia
Mode of delivery:
Controversial
Multidisciplinary meeting required
Termination of pregnancy definitely an option as maternal mortality is high
Scheduled cesarean section in a controlled setting might be the optimal route
Monitoring:
High acuity environment preferably in a center with cardiac surgery expertise
Standard CAS monitors + 5 lead ECG
Arterial line & central line essential
PAC a consideration but must weigh risk vs. benefits
Anesthetic technique:
A carefully titrated epidural likely the best option
Avoid ↓ SVR & treat hypotension with fluids/pressors
Single shot spinal should be avoided as it can cause severe hemodynamic instability
Continuous spinal has been used successfully (slow & careful titration)
General anesthesia has been used successfully
Potential hazards of GA include ↑ PA pressure during laryngoscopy/intubation, adverse effects of PPV on venous return, & negative inotropic effects of certain anesthetic agents
May consider a gentle narcotic-based induction/maintenance, any fetal narcotic effects should be easily reversible
Avoid ergotamine & carboprost; use oxytocin & misoprostol
Managing Acute Episodes/Acute RV Failure = 4 Principles
RV Rate & Rhythm: keep sinus & high-normal rate
RV perfusion & inotropy: maintain with vasopressor/inotrope combo (e.g. norepinephrine & milrinone or epinephrine alone)
RV filling: optimize with CVP, PAC, TEE
↓ PA pressures:
Avoid hypercarbia, hypoxemia, acidosis, hypothermia, high airway pressures
Use pulmonary vasodilators:
Nitric oxide: 20-40ppm
Inhaled flolan
Milrinone: 0.25-0.75 mcg/kg/min; possible loading dose is 50mcg/kg over 10 min
WHO Pulmonary Hypertension Classification
