Topics:
Cardiovascular Disease Prevention - Risk Assessment and Management
Date :
11 Oct 2010
Introduction
Until September 2009 there had not been any ESC guidelines for pre-operative
cardiac risk assessment. This guide discusses the management of cardiac patients who
are undergoing noncardiac surgery and in which heart disease is a potential source of
risk of intraoperative complications.
An estimate based on published data from the Netherlands calculates that in Europe,
with about 490 million people, about 7 million major surgical procedures are
performed each year in patients with cardiac risk. That would lead to 150,000-200,000
life-threatening cardiac complications due to non-cardiac surgery procedures. Elderly
patients require surgery four times more often than the rest of the population, and
although no exact data are available, it is estimated that the number of patients
undergoing surgery in Europe will increase by 25% in 2020 and for the same period,
the elderly population will increase by over 50%.
The risk of complications depends mainly on three aspects: the previous state of the
patient, presence of comorbidities and the extent and duration of surgical procedure.
With regard to cardiac risk, these guidelines recognize three levels of surgery:
interventions at low risk, medium risk and high risk, with estimated rates of cardiac
events (cardiac death and myocardial infarction) within 30 days of <1, 1-5 and 5%
respectively.
PRE-OPERATIVE EVALUATION
It is considered essential in the preoperative cardiac risk assessment to determine
functional capacity (FC), knowing that the inability to climb two flights of stairs or
run a short distance (<4 METs) indicates a low FC and is associated with increased
incidence of postoperative cardiac events. So after thoracic surgery, a low FC has
been associated with increased mortality (relative risk [RR] = 18.7, 95% CI 5.9 to
59). Nevertheless a low FC is not associated with increased mortality after other
noncardiac operations (RR = 0.47, 95% CI, 0.09 to 2.5).
From the available indices for the prediction of cardiac risk in noncardiac surgery
commonly used in our hospitals, the Lee index is in fact a modification of the original
Goldman index, and is considered by many doctors and researchers the best available.
The tests used in risk assessment are different depending on the patient whom we are
evaluating. The indication of diagnostic tests should be performed only if the results
can change the perioperative management. A 12 lead electrocardiogram (ECG) is
usually performed as part of preoperative cardiac risk assessment in patients who are
undergoing noncardiac surgery; however the systematic use of ECG before any
surgery is the subject of debate. Another test is echocardiography, which is not
systematically recommended for the preoperative evaluation of LV function, but can
be performed in asymptomatic patients scheduled for surgery at high risk.
Patients with high levels of stress-induced ischemia are a high-risk population in
which pharmacological treatment is often insufficient for the prevention of
perioperative cardiac events. Therefore should be considered an indication of
screening preoperative ischemia in patients who are undergoing high risk surgery and
have fewer than three clinical risk factors, although in these patients the beneficial
effect of treatment is usually sufficiently cardio protective, which makes stress test
unnecessary. The treadmill or cycle ergometer exercise test are the methods of choice
for detecting ischemia when indicated while pharmacological stress testing with
imaging by nuclear perfusion or echocardiography is more appropriate in patients
with limited exercise capacity. Using the techniques of nuclear medicine in patients
candidate to vascular surgery, during a period of nine years, the rates of cardiac death
or MI at 30 days was 1% in patients with normal tests, 7% in patients with fixed
defects and 9 % in patients with reversible defects on thallium-201 images. But
overall, the positive predictive value of reversible defects in terms of death or
perioperative myocardial infarction has declined in recent years. Elaborating on these
tests for ischemia, dipyridamole stress echocardiography in a recent meta-analysis
showed that the sensitivity and specificity for cardiac death and perioperative MI are
85 and 70% respectively, and positive predictive value 25-45% and negative
predictive value of 90-100%. Keep in mind that coronary angiography is rarely
indicated for risk assessment in the context of non-cardiac surgery, even in patients
with known ischemic heart disease, indications for coronary angiography and
evascularization are similar to those in the non-surgical context.
RISK REDUCTION STRATEGIES
The stress of surgery and anaesthesia should induce ischemia due to the lack of
balance between demand and myocardial oxygen supply. Apart from the risk
reduction strategies tailored to a patient and the type of surgery, preoperative risk
assessment provides the opportunity to review and optimize the control of all
cardiovascular risk factors.

Pharmacological strategies
Beta blockers (BB). The increase in catecholamines that occurs in the perioperative
period is responsible for increased heart rate and contractility with a consequent
increase in myocardial oxygen consumption. The use of BB targets the reduction of
oxygen consumption by reducing heart rate, resulting in a prolongation of diastolic
filling and reduced myocardial contractility. It also improves the redistribution of
coronary flow to subendocardium, the plaque stabilization and increased ventricular
fibrillation threshold.
The indication of preoperative BB should only be set individually based on risk. Its
use in patients at low risk is not justified due to potential side effects of these drugs if
there are no proven benefits. This use is still debated in intermediate risk patients i.e.
patients with one or two clinical risk factors.
However, treatment with BB should be indicated in patients with known ischemic
heart disease or documented myocardial ischemia on preoperative stress testing. It
should also be used in patients scheduled for surgery at high risk. Its use is continued
in patients with ischemic heart disease, arrhythmias and for hypertension. Removing
BB is not recommended in patients treated for stable heart failure secondary to LV
systolic dysfunction. The use of BB should be necessarily reduced or stopped in the
case of decompensated heart failure. If there are no contraindications, the dose of BB
(type I blockers preferably) should be initiated between 30 days and 1 week before the
date of surgery, starting with low doses and increasing doses until a heart rate of 6070 bpm and a systolic pressure > 100 mm Hg. This frequency should be maintained
throughout the perioperative period, extending its use to several months after surgery
to prevent possible occurrence of late cardiac events.
Statins. Because of its lipid-lowering effect, statin therapy is widely used in patients
with coronary heart disease risk. Patients with carotid atherosclerosis, peripheral, or
renal aortic should be treated with statins as secondary prevention regardless of the
surgery. The perioperative use of statins has been shown in clinical studies, so much
so that a meta-analysis included 223,010 patients from 12 retrospective and three
prospective studies and showed that statins significantly reduce mortality by 44% in
noncardiac surgery patients and 59% in vascular surgery patients. There are very few
cases of complications from the use of these drugs and long half-life or slow-release
statins are recommended. It is recommended that statin therapy is initiated preferably
1 month or at least 1 week before surgery. Apply the treatment during the
perioperative period.
Nitrates. The use of nitrates reverses myocardial ischemia, but its use is not justified
because it has not shown benefits in reducing heart attack or cardiovascular death.
Pre-operative use and reducing preload can result in tachycardia and hypotension.
Angiotensin-converting enzyme inhibitors (ACEI). In hypertensive patients it seems
reasonable to suspend 1 day before surgery and restart it when the volume is
stabilized. Likewise it is reasonable to keep them in case of patients with left
ventricular systolic dysfunction if they are stable. If the patient is not using ACEI, its
use should be deferred if guidelines recommendations permit it.
Calcium antagonists. It is recommended to continue their use in patients with
Prinzmetal angina during noncardiac surgery. Diltiazem may be considered in case of
contraindications to the use of beta blockers in the event of non-cardiac surgery.
Diuretics. It is recommended to discontinue their use in hypertensive patients on the
day of surgery and restore oral treatment as soon as possible. If its use is
recommended for heart failure, keep up to the day of surgery and continue with
intravenous administration until normal management can be resumed.
Antiplatelet agents. Aspirin therapy should be maintained in previously treated
patients during the perioperative period. Aspirin should be withdrawn only if the risk
of bleeding outweighs the potential cardiac benefits. In case of minor surgery or
endoscopic procedures it is not usually necessary to stop antiplatelet therapy before
such procedures.
Anticoagulant therapy. Provided that the INR is <1.5 surgery can be safely
undertaken. However, in patients with high thromboembolic risk, disruption of K
antivitamin drugs is dangerous; it should be discontinued five days before surgery and
bridge treatment initiated with unfractionated heparin or low molecular weight
heparin (LMWH) in therapeutic doses intravenously or subcutaneously. A high
thromboembolic risk is present among other conditions, in patients with atrial
fibrillation (AF), mechanical prosthetic heart valves, biological prosthetic heart valves
or mitral valvular repair within the last 3 months, or recent venous thromboembolism
(,3 months) plus thrombophilia. On the day of surgery, the INR should be measured.
If the INR is >1.5 consider postponing the intervention. The type of surgery is another
factor to take into account. Procedures with a high risk of bleeding are those in which
compression cannot be performed. In these cases it is necessary to discontinue oral
anticoagulants and introduce bridging therapy with LMWH. In patients scheduled for
surgery with a low risk of bleeding, it is not necessary to modify the anticoagulant
treatment.
Revascularization The primary objective of prophylactic coronary
revascularization is the prevention of perioperative myocardial infarction.
Revascularization may be effective for treating severe stenoses but it does not
prevent the rupture of vulnerable plaques induced by the stress of surgery,
responsible for at least half of perioperative myocardial infarction. Patients
undergoing coronary artery bypass surgery in the last five years can be referred to
noncardiac surgery if their clinical condition remains stable since the last medical
examination. For coronary interventions, it is recommended to postpone the
noncardiac surgery for at least two weeks in patients undergoing balloon
angioplasty. If there was stent implantation, it is recommended not to waive the
dual antiplatelet therapy and noncardiac surgery is performed after at least six
weeks and, even better, at three months after the intervention by maintaining at
least aspirin therapy. In the case of drug eluting stents implantation, it is
recommended performing noncardiac surgery no sooner than 12 months following
implantation.
Prophylactic revascularization in patients with ischemic heart disease. For stable
patients percutaneous coronary intervention or CABG surgery are recommended
according to current guidelines on the management of angina pectoris. In the case of
unstable patients, provided that surgery can be delayed without risk to the patient, it is
recommended to follow the criteria of the guidelines on the management of unstable
angina. In the unlikely event of the coexistence of a potentially fatal clinical entity
that requires urgent noncardiac surgery and unstable angina, the priority should be
given to surgery. When monitoring such patients it is recommended to use intensive
drug therapy and myocardial revascularization according to guidelines. If PCI is
indicated, the use of uncoated stents or balloon angioplasty is recommended.
SPECIFIC DISEASES

Chronic heart failure
The predictive value of heart failure (HF) when the ejection fraction is <35% is well
established and is an important factor in the Goldman and Detsky score. However this
value is not clear when it comes to patients with heart failure with preserved ejection
fraction. However guidelines recommend treating them in the same way you do with
those with depressed ejection fraction (EF). In patients with HF, the guidelines
recommend the use of beta blockers and ACE inhibitors as first treatment, as also
indicated in patients with symptomatic HF and with EF <40%. Likewise, the
guidelines recommend the use of antagonists of angiotensin receptors, eplerenone, or
diuretics according to specifications already known. When establishing the etiology,
perioperative treatment and discharge should be optimized with the idea of reducing
postoperative complications.

Hypertension
The evidence is not conclusive regarding the use of one or another antihypertensive
agent, so it is recommended to follow the guidelines. In the case of hypertensive
patients with ischemic heart disease and high risk of complications the perioperative
administration of beta blockers is recommended. Antihypertensive treatment must be
maintained until the day of surgery and restarted as soon as possible after surgery. If
the patient has a grade 1 or 2 hypertension, there is no evidence that postponing
surgery to optimize drug therapy is beneficial. However in grade 3 hypertension, the
potential benefits of postponing surgery to optimize treatment should be assessed
against the risk of delaying surgery.

Valve diseases
Patients with known or suspected valvular heart disease should have an
echocardiogram. If VHD is severe, clinical evaluation and treatment is recommended
before noncardiac surgery.

Aortic stenosis
In case of urgent noncardiac surgery, this should be performed with hemodynamic
monitoring. If non-urgent surgery, the presence of symptoms is very important for
decision making. In symptomatic patients aortic valve replacement should be
considered before elective surgery. If it is symptomatic but valve replacement is not
appropriate for any reason, noncardiac surgery should be undertaken only if
absolutely necessary.

Mitral stenosis
Noncardiac surgery can be performed with a low risk if the patient is asymptomatic
with non-significant mitral stenosis and pulmonary pressure <50 mmHg. It is essential
to control heart rate and fluid overload, avoid the development of Atrial Fibrillation
(AF) and have a strict control of anticoagulation. In patients with symptomatic or
significant mitral stenosis with pulmonary hypertension, the benefit of repairing the
mitral disease prior to noncardiac surgery should be considered, especially if at high
risk.

Aortic and mitral regurgitation
These valvular diseases increase the number of perioperative complications. If the
patient is asymptomatic, although these are severe valvular disease, if left ventricular
function is preserved, noncardiac surgery can be performed without additional risk. If
it is symptomatic or asymptomatic patients with EF <30%, noncardiac surgery should
be performed only if absolutely necessary.

Prosthetic valves
Previously operated patients have additional risk. They can be operated and caution is
taken to establish a prophylactic treatment to prevent endocarditis (as recommended
by the guidelines). The anticoagulant treatment is optimized by replacing intravenous
or subcutaneous heparin at therapeutic doses.
ARRHYTHMIAS
The incidence of perioperative arrhythmias is 70% in patients undergoing general
anaesthesia.

Ventricular arrhythmias
Almost half of high-risk patients undergoing noncardiac surgery have premature
ventricular beats or non-sustained monomorphic ventricular tachycardia, which is not
associated with poor prognosis. Regardless, the guideline recommendations to prevent
sudden death in patients with ventricular arrhythmias should be followed. Sustained
monomorphic ventricular tachycardia should be treated with intravenous amiodarone,
also used if the patient is unstable and resistant to electrical cardiovesrión. In
polymorphic ventricular tachycardia, electrical cardioversion should be performed.
Amiodarone can be used in the absence of no long QT syndrome. In case of
occurrence of torsades de pointes it is very important to remove the offending drugs,
correct electrolytes and implement specific treatment guidelines.

Supraventricular arrhythmias
There are more frequent supraventricular tachycardia (PSVT) and AF than ventricular
arrhythmias. If PSVT, vagal manoeuvres and adenosine are the treatments of choice.
If these fail, we recommend intravenous diltiazem or betablockers. In case of AF, the
aim of the treatment is to slow the ventricular rate (prefer diltiazem or beta-blockers,
rather than with verapamil). Digoxin is allowed only for patients with chronic heart
failure.

Bradyarrhythmias
Less than 0.5% of patients operated in functional class 1 or 2 have serious
arrhythmias, and most respond to drugs or transesophageal, or transcutaneous
temporary pacing. Temporary pacing is rarely needed, and its indications are the same
as those of permanent stimulation.

Pacemaker / automatic implantable defibrillator
Patients with these devices may be at risk from electrocautery, but you can minimize
this problem with different techniques in the preoperative scalpel or changes in the
pacemaker. In the case of the defibrillator is recommended deactivate prior to surgery
and reactivate later. The guidelines recommend that the hospital management appoints
a person responsible for programming implantable devices before and after surgery.
RENAL DISEASE
It is recommended that preoperative renal function is considered as an independent
risk factor for prognosis in the short and long term. In major vascular surgery,
creatinine clearance 64 ml / min is the cutoff that provided the greatest sensitivity and
specificity for predicting postoperative mortality. It is also important to identify
patients whose renal function may worsen perioperative and to establish support
measures. In those at risk for contrast-induced nephropathy, hydration with isotonic
sodium chloride (with or without N-acetylcysteine) is recommended for prophylaxis
prior to cardiac imaging tests that require contrast.
CEREBROSVASCULAR DISEASE
Risk factors of perioperative cerebrovascular events, both symptomatic and
asymptomatic, and transient or permanent (TIA / stroke) are embolism and small or
large vessel hemodynamic deterioration. The prevention of strokes is more directed to
disciplinary control of hypertension, hyperlipidemia, diabetes mellitus etc. The use of
antiplatelet agents and anticoagulants has been shown widely beneficial in both
primary and secondary prevention. Most strokes are not related to hypoperfusion;
ischemic and embolic mechanisms are much more common than hemodynamic
deterioration. A history of recent TIA or stroke is a strong predictor of perioperative
risk, so it must be identified in the assessment of the history and neurological state. In
case of carotid stenosis > 70% it is recommended to establish additional treatment
such as antiplatelet therapy and / or surgery.
LUNG DISEASE
Complications that occur in patients with lung diseases are primarily a result of the
appearance of atelectasis during general anaesthesia, especially in thoracic and
abdominal surgery in smokers. Patients with COPD have a higher number of
cardiovascular diseases, especially if you have a cor pulmonare or a reduced forced
expiratory volume in one second. However, despite the relationship between COPD
and cardiovascular disease there is clear evidence that COPD is associated with an
increased risk of perioperative cardiac complications.
In patients with lung disease scheduled for noncardiac surgery, preoperative treatment
goals are to optimize lung function and minimize pulmonary complications.
Perioperative cardiac management is similar to patients without COPD, and there are
no contraindications for the use of cardioselective beta-blockers or statins in these
patients.
Pulmonary arterial hypertension (PAH) is another condition that increases the risk of
surgical complications, especially right ventricular failure, myocardial ischemia and
perioperative hypoxia. There is evidence that in patients undergoing noncardiac
surgery with high risk of PAH there is a perioperative cardiopulmonary complication
rate of 38% and a mortality of 7%. Anaesthesia and surgery may be complicated by
acute right heart failure caused by increased pulmonary vascular resistance, related to
the impairment of pulmonary ventilation typical of the operative and postoperative
periods in thoracic and abdominal surgery. Before intervention it is recommended to
optimize the pharmacological treatment of patients with PAH. Also the specific
treatment regimen of PAH should not be stopped for more than 12h due to
perioperative fasting. In case of progression to heart failure after surgery it is
recommended to adjust the dose of diuretics and dobutamine use if necessary. In case
of severe right HF, not responsive to supportive therapy, inhaled nitric oxide or
intravenous epoprostenol may be indicated.
PERIOPERATIVE MONITORING

Electrocardiography
We recommend 12-lead electrocardiogram monitoring in all patients undergoing
surgery, although we recommend the use of certain combinations of leads to enhance
detection of ischemia during surgery.

Tranoesophageal echocardiography (TEE)
There are few data on the evidence supporting the use of this technique in noncardiac
surgery. The performance of TEE should be considered in patients with ST segment
changes detected in the intraoperative or perioperative ECG. The use of TEE is also
recommended in case of acute and severe hemodynamic instability or life-threatening
disturbances during or after surgery. TEE monitoring can be considered in patients at
high risk of major hemodynamic changes during and after major noncardiac surgery.
It can also be considered in patients with severe valvular lesions during major
noncardiac surgery with significant hemodynamic stress.

Right heart catheterization
There are no data to justify its implementation in noncardiac surgery.

Impaired glucose metabolism
Diabetes mellitus is a major risk factor for perioperative cardiac complications and
death. In the absence of diabetes, hyperglycemia has an important role and, whenever
possible, requires preoperative management. We recommend postoperative prevention
of hyperglycemia by intensive insulin therapy in adults following high-risk major
surgery or complications that require ICU admission. Intraoperative prevention of
hyperglycemia can be considered by administering insulin, even in cases of elective
surgery without complications.
ANAESTHESIA

Intraoperative management of anaesthesia
It is considered that the choice of the anaesthetic agent has little relevance to the
clinical course of patients when on life support. Most anaesthetic techniques reduce
sympathetic tone causing arterial vasodilatation and hypotension; during anaesthesia it
is important to ensure the maintenance of adequate perfusion pressure in the different
organs.

Neuraxial techniques
The use of thoracic epidural anaesthesia for high-risk surgery should be considered in
patients with heart disease. There is little evidence for the superiority of regional over
general anaesthesia for patient outcome and reduced postoperative morbidity and
mortality.

Management of postoperative pain
It is suffered by 5-10% of patients and may increase the sympathetic impulse and
delay recovery, although it is unclear whether it can cause complications. The
neuraxial analgesia with anaesthetic/local opioids and/or alpha-2 agonists, intravenous
opioids, alone or in combination with nonsteroidal anti-inflammatory drugs seems to
be the most effective. The patient-controlled analgesia has advantages but has not
shown differences in morbidity or final results. The use of nonsteroidal antiinflammatory drugs or cyclooxygenase-2 inhibitors is not recommended for
postoperative pain management in patients with renal or cardiac failure, myocardial
ischemia or the elderly, or in those treated with diuretics or in cases of hemodynamic
instability.
Conclusion
PUTTING THE PUZZLE TOGETHER
As a final summary, the guidelines present an algorithm of seven steps in defining the
comprehensive preoperative strategy. This begins by establishing the degree of
urgency of the intervention and secondly to evaluate the presence of so-called
unstable heart disease (which will decisively influence the decision to perform or not
an intervention). These diseases are: unstable angina, acute heart failure, significant
cardiac arrhythmias, symptomatic valvular disease, myocardial infarction within the
past 30 days and residual myocardial ischemia. Steps 3, 4 and 5 focus on assessing the
patient's surgical risk and on determining their functional capacity. Finally, step 6 is to
explore the presence or absence of clinical cardiac risk factors afflicting the patient,
including: angina pectoris, previous myocardial infarction, heart failure, stroke / TIA,
diabetes mellitus or renal dysfunction insulin-dependent. According to the presence of
these risk factors, step 7 determines whether specific cardiac diagnostic tests are
required or not. When this last point is finally clarified, we decide to perform the
scheduled surgery.