Perioperative cardiac medications in high risk patients

PERIOPERATIVE USE OF
CARDIAC MEDICATION IN
HIGH RISK PATIENTS

 Introduction
 what are the High risk patient?
 Different diseased cardiac conditions
 Different cardiac medications
 Drug Recommendation with anaesthetic
consideration
 Conclusion

INTRODUCTION
 Perioperative period is a stressful condition
where a number of physiological changes take
place which can result in a change in drug
requirement.
 May be due to altered hepatic or renal function
or neuro hormonal changes.

INTRODUCTION
 It is estimated that one fourth of all patients
undergoing a surgical procedure are taking long-
term medications
 The issues surrounding the decision to
discontinue such medications before surgery and
when to reinstitute them are complex
 In the preoperative period, it is important to
avoid the use of medications that may negatively
interacts with anesthetic agents.

INTRODUCTION
 Antihypertensive medications may cause
cardiovascular complications, such as
hypotension or myocardial ischemia.
 Psychoactive medications may cause prolonged
sedation and withdrawal symptoms may develop
 Antithrombotic agents may increase the risks of
bleeding during surgery

INTRODUCTION
 Postoperatively, the concern shifts towards
avoiding withdrawal symptoms that may
develop and possible progression of the
underlying disease if the medications are not
restarted in a timely fashion

Relative cardiac risk index
INDICESTO PREDICT PREOPERATIVE CARDIAC
MORBIDITY:
 Lee et al (1999) identified six independent risk
correlates.
1.H/O Ischemic heart disease - 1
2.H/O Congestive HF - 1
3.H/O Cerebral vascular disease- 1
4.High risk surgery - 1
5.Preoperative insulin treatment for DM- 1
6.Preoperative creatinine > 2mg/dl - 1

Cardiac medication used for
disease
 Coronary Artery Disease
 Hypertension
 Heart Failure
 Cardiomyopathy
 Valvular Heart Diseases
 Arrythmias and Conduction Defects
 Implanted Pacemakers.

Cardiac medications
 B-blockers
 Calcium channel blockers
 ACE inhibitors/AR antagonists
 Diuretics
 Nitrates
 Digitalis
 Amiodarone
 Anti platelet drugs
 statins

BETA BLOCKERS
MECHANISM OF ACTION:
 Decrease oxygen consumption
 Improve myocardial metabolism
 Block the action of catecholamines
 Decrease sympathetic outflow
 Shift ODC to right leading to increased oxygen
supply
 Suppress dysrrhymias
 LV remodelling

RECOMMENDATION
 Perioperative betablocker therapy to be
instituted before CABG if LVEF > 30% and preop
status allows it.
 Pt already on BB should take on morning of
surgery and renew it immediate past op
 In pt with COPD/reactive airway disease,
preferable to use cardio selective agents

Recommendations for Beta-Blocker Medical
Therapy
Beta blockers should be
continued in patients
undergoing surgery who are
receiving beta blockers for
treatment of conditions with
ACCF/AHA Class I guideline
indications for the drugs
III IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIIaIIaIIa IIbIIbIIb IIIIIIIII

Therapy
Beta blockers titrated to heart rate and blood
pressure are probably recommended for patients
undergoing vascular surgery who are at high cardiac
risk owing to coronary artery disease or the finding of
cardiac ischemia on preoperative testing (4, 5).
Beta blockers titrated to heart rate and blood
pressure are reasonable for patients in whom
preoperative assessment for vascular surgery
identifies high cardiac risk, as defined by the
presence of > 1 clinical risk factor.*
Modified
Modified
I IIa IIb III

Therapy
Beta blockers titrated to heart rate and
blood pressure are reasonable for patients
in whom preoperative assessment
identifies coronary artery disease or high
cardiac risk, as defined by the presence of
> 1 clinical risk factor,* who are undergoing
intermediate-risk surgery.
NO CHANGE

Therapy
The usefulness of beta blockers is uncertain for
patients who are undergoing either
intermediate-risk procedures or vascular
surgery in whom preoperative assessment
identifies a single clinical risk factor in the
absence of coronary artery disease.*
The usefulness of beta blockers is uncertain in
patients undergoing vascular surgery with no
clinical risk factors who are not currently taking
beta blockers.
NO CHANGE
NO CHANGE

Therapy
Beta blockers should not be given to patients
undergoing surgery who have absolute
contraindications to beta blockade.
Routine administration of high-dose beta
blockers in the absence of dose titration is not
useful and may be harmful to patients not
currently taking beta blockers who are
undergoing noncardiac surgery.
NO CHANGE
New
III IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIII

ANAESTHETIC IMPLICATIONS
 Decrease in HR, decrease in BP and myocardial
depressant effects of BB and GA agents appear
to be additive
 Severe decrease in HR and block may occur with
drugs like fentanyl, vecuronium and propofol.
 Intubation, incision and extubation occur during
periop period result in a surge in endogenous
catecholamines.

 ISIS-I study (International study of infarct
survival)
 MIAMI study (Metoprolol in AMI)
 MAPHY study (MetoprololVsThiazide diuretics
in HT)
 ASIST study (Atenolol ischaemia study)
-have shown that BB is effective in reducing
cardiac complications and could be safely used in
the periop period.

CCB - ADVANTAGES
 Well tolerated and do not alter exercise
tolerance like BB’s
 Do not cause fluid retention although ankle
edema is a well known side effect.
 Control dysrhythmias
 Prevent coronary artery spasm
 Anti-HT effect
 Negative inotropic, chronotropic and
dromotropic

CCB – DISADVANTAGES
 Low response to inotropes and vasopressors
 AV node conduction block
 Peripheral vasodilation after CPB
 Profound brady cardia and low BP when given in
presence of BB

Perioperative Calcium Channel Blockers
 Calcium channel blockers significantly reduce
1. Myocardial ischemia
2. Supraventricular tachycardia
3. Morbidity/mortality.
*Large scale trial needed to define the value of
these agents.

RECOMMENDATIONS
 Preferable to continue CCB upto the time of
surgery, including an oral dose on the morning of
surgery

 CCB can also enhance the action of muscle
relaxants and lowers MAC of inhaled agents
 CCB being vasodilators and myocardial
depressants are similar to volatile gents –
synergistic role
 CCB must be administered with caution to
patient with impaired LV function or
hypovolemia

ACEI/ARA
 Renin-AT system plays a significant role in
maintaining intraop BP
 Inhibitors of this system exaggerate the
hypotensive effects of anaesthesia, can cause
refractory hypotension and reduced organ
perfusion

 Patients treated chronically with ACEI will have
significant reduction in MAP,CI,PCWP,SVR and
HR in periop period
 Increased incidence of low BP at induction
requiring vasopressors after induction

RECOMMENDATIONS
 Preferable not to continue ACEI/ARA upto day of surgery
 OMIT on the morning of surgery
 If continued, it is mandatory to maintain an adequate
volume load and BP with vasopressor, if necessary
 Discontinue ACEI preop (12 hours preop if captopril (or) 24
hours preop if enalapril) and substitute shorter acting IV
anti-HT drugs
 ACEI may increase insulin sensitivity and hypoglycemia-
concern in DM patients

DIURETICS
 Cause significant dyselectrolytemia and fluid
imbalance
 Should be discontinued preop
 Efficacy comes down with decrease in GFR

NITRATES
 Weightman etal found nitrates to be independent
predictors of mortality after CABG surgery
 This may be due to tolerance to nitrates which in
turn decreases the effectiveness of nitrates
causing
decreased vasodilatation of IMA graft,
decreased inhibition of platelets,
decreased ischaemic preconditioning,
decreased sensitivity to vasoconstrictors

NITRATES
 Preop discontinuation results in rebound coronary
vasoconstriction and worsening of myocardial
ischaemia

RECOMMENDATIONS
 Regarding patients on therapeutic and prophylactic
NTG, this agent should be continued until and perhaps
beyond induction of anaesthesia, especially in patients
who were preop on nitrates for angina

DIGITALIS
INDICATIONS
 Prevents post operative arrhythmias after
lung surgery
 Controls ventricular rate in patients with atrial
fibrillation
 Improves cardiac contractility in patients with
congestive cardiac failure

DISADVANTAGES
 Narrow margin of safety
 Exacerbation of hypokalemic risk –K+
concentration can fluctuate widely during
anaesthesia due to fluid shifts,ventilatory acid-
base dearrangements and adjuvant treatments
 Intraoperative arrhythmia due to digitalis may be
difficult to differentiate from those having other
sources

DISADVANTAGES
 Digitalis toxicity can present with such diverse
cardiac arrhythymais on junctional escape
rhythm,PVCVentricular bigeminy or
trigeminy,JunctionalTachycardia, PAT
with/without, sinus arrest, Mobitz type I and II
block orVT
 Prophylactic digitalization to prevent arrhythmias
after lung surgery has proven ineffective in a
number of Randomized controlled studies

RECOMMENDATION
 As digitalis has a long blood half-life(36 Hrs),pre-op
discontinuation on the day of surgery should not result
in a significant decrease in blood levels.
 As intravenous preparation is available,the drug can be
supplemented if required.
 Moreover heart rate can be effectively controlled with
b-blockers and cardiac contractility can be increased
with inotropes.pre-op discontinuation of digitalis is
recommended

AMIODARONE
 Antiarrhythmic agent
 Used to treat recurrent SVT &VT
 It causes a significant reduction in the incidence of post-op
atrial fibrillation and duration of hospitilization
 Side effects
Pulmonary infiltrates
Hypo/Hyperthyroidism
Peripheral neuropathy
Deranged LFT
Prolonged QT interval

AMIODARONE
 Increase quinidine, procainamide, digoxin
levels
 Prolongation of Prothrombin time causing
bleeding in patient on warfarin
 Amiodarone increase phenytoin levels and
phenytoin enhance the conversion of
amiodarone
 Synergism with BB

RECOMMENDATIONS
 As amiodarone has a longT1/2 (29 days), and
pharmacologic of effects may persists for over 45 days
after its discontinuation, effective preoperatively
discontinuation is not feasible
 Omit morning dose as IV form is available and is fact acting
 Risk of discontinuation increases reappearance of life
threatening ventricular arrhythmias
 Amiodarone has to be started 7 days preop
 This is both inconvenient and costly

RECOMMENDATIONS
 To discontinue, aspirin, clopidogrel &Ticlopidine
atleast 5-7 days before surgery to reduce the risk
of periop bleeding & reinstitute them when the
bleeding risk is diminished.

Recommendations for Statin Therapy
For patients currently taking statins and scheduled
for noncardiac surgery, statins should be continued.
For patients undergoing vascular surgery with or
without clinical risk factors, statin use is reasonable.
For patients with at least 1 clinical risk factor who are
undergoing intermediate-risk procedures,
statins may be considered.

Recommendations for Alpha-2Agonists
Alpha-2 agonists for perioperative control of
hypertension may be considered for patients
with known CAD or at least 1 clinical risk factor
who are undergoing surgery.
Alpha-2 agonists should not be given to patients
undergoing surgery who have contraindications
to this medication.

Perioperative arrhythmias & conduction
disturbances
 In patients with documented
hemodynamically significant or symptomatic
arrhythmias, acute treatment is indicated.
 (1) supraventricular arrhythmias:
 Beta blockers (most effective)
 CCB
 Digoxin (least effective)

Perioperative arrhythmias & conduction
disturbances
 (2)Ventricular arrhythmias:
 PVC
 Complex ventricular ectopy Do not need
therapy
 Nonsustained tachycardia
 Sustained/symptomatic ventricular tachycardia
 Lidocaine
 Procainamide
 Amiodarone

Conclusion
 Successful perioperative evaluation and management of
high risk cardiac patients undergoing noncardiac surgery
requires careful teamwork and communication between
surgeon, anaesthesiologist and the patient’s primary
caregiver.

CONCLUSION
 The decision to withhold and restart medications
should be based on the
pharmacokinetics and
pharmacodynamics of the agent,
available clinical data and
expert opinion
 Anaesthetists should exercise diligence in obtaining an
accurate medication history on all preoperative
patients and in reviewing the medications in the post
operative orders

Perioperative cardiac medications in high risk patients

Perioperative cardiac medications in high risk patients

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Perioperative cardiac medications in high risk patients