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Myocardial Injury after Noncardiac Surgery and
Perioperative Atrial Fibrillation: From Evidence to
Clinical Practice
Flavia K. Borges, MD, PhD
1,2,3
, Sandra Ofori, MD
1,4
, Maura Marcucci, MD
1,2,3,4
1
Anesthesia, Perioperative Medicine, and Surgical Research Unit, Population Health Research Institute, Hamilton, Canada;
2
Department
of Medicine, McMaster University, Hamilton, Canada;
3
Division of Perioperative Care, Department of Health Research Methods,
Evidence, and Impact, McMaster University, Hamilton, Canada;
4
Health Research Methodology, Department of Health Research
Methods, Evidence, and Impact, McMaster University, Hamilton, Canada
Address for correspondence: Maura.Marcucci2@phri.ca
Submitted: November 18, 2020. Accepted: 8 January 2021. Published: March 16, 2021. DOI: 1022374/cjgim.v16iSP1.530.
ABSTRACT
One in 60 patients who undergo major noncardiac surgery dies within 30 days following surgery.
The most common cause is cardiac complications, of which myocardial injury after noncardiac
surgery (MINS) and perioperative atrial fibrillation (POAF) are common, affecting about 18 and
11% of adults, respectively, after noncardiac surgery. Patients who suffer MINS are at a higher
risk of death compared to patients without MINS. Similarly, patients who develop POAF are
at a higher risk of stroke and death compared to patients who do not. Most patients who suffer
MINS are asymptomatic, and its diagnosis is not possible without routine troponin monitoring.
Observational studies support the use of statins and aspirin in the management of patients with
MINS. The only randomized controlled trial to date that has specifically addressed the management
of MINS was the MANAGE trial that demonstrated the efficacy and safety of intermediate
dose dabigatran in this population. There are no specific prediction models for POAF and no
randomised controlled trial evidence to guide the specific management of POAF. Management
guidelines in the acute period follow the management of nonoperative atrial fibrillation. The
role of long-term anticoagulation in this population is still uncertain and should be guided by
a shared care decision model with the patient, and with consideration of the individual risk for
stroke balanced against the risk of bleeding. In this review, we present a case-based approach to
the detection, prognosis, and management of MINS and POAF based on the existing evidence.
RÉSUMÉ
Un patient sur 60 qui subit une intervention chirurgicale majeure non cardiaque meurt dans les
30jours suivant l’opération. La cause la plus fréquente est celle des complications cardiaques, dont
les lésions myocardiques après une chirurgie non cardiaque (LMCNC) et la fibrillation auriculaire
périopératoire (FAPO) sont courantes et touchent respectivement environ 18 et 11% des adultes
après une chirurgie non cardiaque. Les patients présentant des LMCNC sont exposés à un risque
plus élevé de décès que les patients qui ne présentent pas de LMCNC. De même, les patients chez
qui on voit apparaître une FAPO ont un risque plus élevé d’accident vasculaire cérébral et de décès
que ceux qui ne connaîtront pas cette complication. La plupart des patients atteints de LMCNC
sont asymptomatiques, et il est impossible d’établir un diagnostic sans surveiller régulièrement la
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Introduction
Globally, over 300 million adults undergo noncardiac surgery
every year.
1
Noncardiac surgery can improve patient quality of life
and prolong survival. However, perioperative complications are
not uncommon. Acute cardiovascular events are among the most
frequent complications.
2,3
They include myocardial injury after
noncardiac surgery (MINS) and perioperative atrial fibrillation
(POAF). This review offers insights into the management of
these complications using a case-based approach.
Myocardial Injury after Noncardiac Surgery:
Clinical Scenario
Ms. A.S. is a 77-year-old female who underwent hip fracture
surgery. She had no risk factors for, or a previous history of,
cardiovascular disease. Preoperatively, she was independent in
all activities of daily living. Intraoperatively, she experienced
hypotension with a systolic blood pressure (BP) <90 mmHg
for 15 min. Routine postoperative monitoring showed high-
sensitivity troponin I (hsTnI) at 64 ng/L (upper reference limit
[URL] 30 ng/L) on postoperative day 1. She had no chest pain
or shortness of breath. Her heart rate was 86 beats/min, BP
134/75 was mmHg, and heart and lung sounds were normal.
The electrocardiogram (ECG) was unremarkable. HsTnI peaked
at 75 ng/L the next day. She remained asymptomatic. She was
discharged home on aspirin and a statin, with a plan to follow-up
with her family physician and surgeon.
One month later, she presented to the emergency department
with chest pain. Her BP was 138/78 mmHg, and her heart rate
was 72 beats/min. The exam was unremarkable. ECG showed
a new left bundle branch block (LBBB). Initial HsTnI was
88 ng/L and peaked at 1468 ng/L 12 h later. She underwent urgent
cardiac catheterization. Left ventriculogram showed preserved
left ventricular ejection fraction with no regional wall motion
abnormalities but significant 3-vessel coronary artery disease
(CAD). She subsequently underwent triple coronary artery bypass
graft surgery. She was discharged home in a stable condition on
aspirin, an angiotensin-converting-enzyme (ACE) inhibitor, a
beta-blocker, and a high-dose statin.
What Is MINS?
MINS is defined as an acute elevation of troponin due to
myocardial ischemia occuring during or within 30 days after
noncardiac surgery. MINS includes patients that fulfil the
Universal Definition of myocardial infarction (MI),
4
and patients
troponine. Des études d’observation appuient l’utilisation des statines et de l’aspirine dans la prise
en charge des patients atteints de LMCNC. À ce jour, le seul essai contrôlé randomisé qui s’est
penché précisément sur le traitement des LMCNC est l’essai MANAGE qui a démontré l’efficacité
et l’innocuité du dabigatran à dose intermédiaire chez cette population. Il n’existe aucun modèle de
prédiction précis pour la FAPO ni aucune donnée probante provenant d’essais contrôlés randomisés
pour orienter précisément son traitement. Les lignes directrices concernant la prise en charge au
cours de la période aiguë suivent celles de la prise en charge de la fibrillation auriculaire non liée à
une opération. Le rôle de l’anticoagulation à long terme chez cette population est encore incertain
et devrait être guidé par un modèle de prise de décision partagée avec le patient et tenir compte du
risque individuel d’accident vasculaire cérébral par rapport à celui d’hémorragie. Dans cette revue,
nous présentons une approche fondée sur des cas pour la détection, le pronostic et le traitement
des LMCNC et de la FAPO sur la base des données probantes existantes.
Key Learning Points
• Myocardial injury after noncardiac surgery (MINS) is frequent and is associated with
increased 30-day and 1-year mortality and cardiovascular events.
• MINS occurs without symptoms in most of the cases and would remain undetected without
routine postoperative troponin monitoring.
• Further risk stratification, secondary cardiovascular prevention, and close follow-up should be
considered in patients with MINS.
• Perioperative atrial fibrillation (POAF) complicates many noncardiac surgeries and is associated
with in-hospital adverse outcome and increased long-term risk of stroke and mortality.
• Management of POAF includes identification and treatment of triggers, acute rhythm or
rate control, assessment of long-term risk of recurrence and cardiometabolic risk, and
consideration for long-term oral anticoagulation.
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with ischemic troponin elevation without any ischemic features
(e.g., chest pain or ischemic electrocardiographic findings).
5
Postoperative troponin elevation due to other nonischemic
etiologies (e.g., pulmonary embolism, sepsis) are not considered
as MINS.
What Is the Prognostic Impact of MINS?
MINS is the most common cardiovascular complication after
noncardiac surgery. Patients with MINS have a higher 30-day
mortality and a higher risk of recurrent short- and long-term
cardiovascular complications.
5,6
A recent systematic review
(169studies and >530,000 patients) estimated the incidence of
MINS at 18%.
7
Compared to patients without MINS, those with
MINS had higher mortality, both in hospital (8.1%, vs 0.4%,;
relative risk [RR] 8.3, 95% confidence interval [CI], 4.2–16.6) and
at 1 year after surgery (20.6% vs 5.1%; RR 4.1, 95% CI, 3.0–5.6).
What Are the Troponin Thresholds for MINS?
The Vascular events In noncardiac Surgery patIents cOhort
evaluatioN (VISION) study included a representative sample of
40,004 patients undergoing inpatient noncardiac surgery
8
and
was the first study to establish prognostically relevant troponin
thresholds for MINS independently associated with death at
30days. A fourth generation nonhigh-sensitivity troponin T
(TnT) ≥0.03 ng/mL or a fifth generation high-sensitivity troponin
T (hsTnT) of 20 to <65 ng/L with an absolute change of ≥5 ng/L
or a hsTnT level ≥65 ng/L were independently associated with
30-day postoperative mortality.
5,8
VISION substudies have also
established optimal hsTnI thresholds for MINS. A hsTnI ≥60
ng/L (ARCHITECT STAT Abbot assay)
9
and a hsTnI ≥75 ng/L
(Siemens Healthineers ADVIA Centaur Assay)
10
are associated
with major cardiovascular events 30 days after noncardiac
surgery. For other troponin assays, physicians should consider
any elevation above the 99th percentile URL as the threshold
for MINS.
5
Importantly, the VISION Study demonstrated that the
higher the postoperative troponin peak, the higher the 30-day
mortality. Patients with a peak postoperative hsTnT levels of 65
to <1000 ng/L had 30-day mortality rates of 9.1%, and patients
with hsTnT levels of ≥1000 ng/L had 29.6% 30-day mortality.
8
Which Patients Should be Monitored for MINS?
Patients with MINS are more likely to be older, male, and have
cardiovascular risk factors.
7,11–13
The Canadian Cardiovascular
Society (CCS) Guidelines
14
recommend that patients undergoing
noncardiac surgery with a Revised Cardiac Risk Index score
(RCRI) ≥1,
15
age ≥65 years or 45–64 years with significant
cardiovascular disease, or patients with elevated preoperative
N-terminal prohormone brain natriuretic peptide (NT-proBNP
≥ 300 ng/L) or brain natriuretic peptide (BNP ≥ 92 mg/L) be
routinely monitored for MINS. Recent data from the VISION
cohort demonstrated that among 10,402 patients, compared
with a reference preoperative NT-proBNP <100 pg/mL, adjusted
hazard ratios [aHR] for the occurrence of the primary outcome
(i.e., vascular death or MINS) within 30 days after noncardiac
surgery were 2.27 (95% CI, 1.90 to 2.70) for NT-proBNP of 100
to <200 pg/mL, 3.63 (CI, 3.13 to 4.21) for NT-proBNP of 200 to
<1500 pg/mL, and 5.82 (CI, 4.81 to 7.05) for NT-proBNP ≥1500
pg/mL. The associated incidence of the primary outcome was
12.3, 20.8, and 37.5%, respectively.
16
The European Society of
Cardiology (ESC) guidelines suggest biomarker measurements
in high-risk patients, including NT-proBNP for prognosis
assessment and cardiac troponin both before and 48–72 h after
major surgery.
17,18
The most recent Universal definition of MI
statement also recommends perioperative troponin surveillance
for high-risk individuals undergoing noncardiac surgery.
19
In the VISION study, 38.2% of patients who had MINS
experienced this on the day of surgery, 39.4% on postoperative day
1, 16.5% on postoperative day 2, and only 5.3% on postoperative
day 3.
8
Importantly, in up to 93% of cases, the index MINS
event is asymptomatic.
8
After surgery, patients are commonly
on analgesics that can mask ischemic symptoms. Compared to
patients without MINS, patients who have MINS, without or
with ischemic features, have a higher 30-day mortality rate (0.6%
vs 2.9% vs 8.5%, respectively),
8
thereby supporting the need for
routine perioperative troponin surveillance. The ESC and the
CCS guidelines recommend that troponin should be measured
daily after surgery, for 48–72 h or until peak, complemented
with ECGs to detect ischemia.
14,17
What Is the Rationale and Evidence for the Management
of Patients with MINS?
Troponin elevation after noncardiac surgery is associated with
adverse outcomes. Patients with MINS are also more likely
to have known or unknown underlying CAD than patients
without MINS. The Coronary CTA VISION Study showed that
underlying coronary stenosis was common among patients who
had a perioperative MI (4% had normal coronary arteries on
Cardiac Computed Tomography Angiography [CTA] and 72%
had obstructive CAD).
11
Therefore, it is reasonable to consider
close monitoring and follow-up with secondary cardiovascular
prevention to reduce the risk of subsequent cardiovascular events.
The Management of Myocardial Injury After Noncardiac Surgery
(MANAGE)
20,21
trial was the first randomized controlled trial
(RCT) to evaluate treatment strategies in patients with MINS.
In MANAGE, 1,754 patients were randomly allocated to receive
dabigatran, 110 mg twice-daily, or placebo, from the day of
randomization (median of 5 days postoperatively) to the end of
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follow-up (16 months). The primary outcome (a composite of
vascular mortality and nonfatal MI, nonhaemorrhagic stroke,
peripheral arterial thrombosis, amputation, and symptomatic
venous thromboembolism) occured in 97 (11%) of 877 patients
in the dabigatran versus 133 (15%) of 877 patients in the
placebo group (HR 0.72; 95% CI 0.55–0.93; P = 0.0115), with
no significant increase in major bleeding (HR = 0.92; 95%
CI: 0.55–1.53). Dabigatran was associated with an increase in
minor bleeding (15% with dabigatran vs 10 % with placebo;
HR 1.64; CI 95% 1.25–2.15). About 60% of patients were on
aspirin and only 3% were on dual antiplatelet therapy at the time
of randomization. There is no RCT on other medications for
secondary cardiovascular prevention after perioperative ischemic
events. A multivariable prospective analysis of 415 patients with
a perioperative MI demonstrated that the initiation of aspirin
and statin was associated with a reduction in 30-day mortality
(adjusted odds ratio [aOR] = 0.54; 95% CI: 0.29–0.99, and aOR
= 0.26; 95% CI: 0.13–0.54, respectively).
22
A case–control study
demonstrated that cardiovascular medication intensification (i.e.,
the introduction of at least 1 among antiplatelets, statin, beta-
blockers, and angiotensin II converting enzyme inhibitors [ACEI])
was associated with a reduction of subsequent cardiovascular
events at 1 year for patients who suffered a perioperative MI.
23
The CCS Guidelines recommend long-term aspirin and statin
therapy for patients with MINS.
14
What Is the Approach to Management of MINS?
The patient in the abovementioned scenario illustrates that
patients with MINS require close follow-up and that MINS might
unmask undiagnosed CAD. The following points and Figure 1
summarize our management approach to patients with MINS.
In-hospital:
1. Assess for high-risk features (persistent chest pain,
ST elevation/new LBBB, dynamic ECG changes, or
hemodynamic instability). If present, consider inpatient
echocardiogram, cardiac catheterization, and cardiology
consultation. After the acute phase or among stable
patients, further risk stratification with cardiac stress
testing can be done while in hospital.
2. Identify nonischemic causes for troponin rise and
manage triggers (anemia, tachycardia, hypotension,
pulmonary embolism, sepsis, etc.).
3. Implement medications for cardiovascular disease
prevention while in hospital including moderate-
to-high dose statin and aspirin. Consider adding
intermediate dose dabigatran. Timing for the initiation
of aspirin and the addition of dabigatran should
consider bleeding concerns and be discussed with the
surgeon.
4. Discuss with the patient about optimal management of
cardiovascular risk factors (i.e., lifestyle modification,
smoking cessation, BP, and diabetes control if
indicated).
Outpatient:
1. Short-term clinical follow-up within 2–4 weeks
whenever possible.
2. Outpatient risk stratification might include noninvasive
cardiac testing with stress echocardiography, nuclear
stress tests, or coronary CT angiogram. Where
available, Positron Emission Tomography scan with
flow quantification can be performed, mainly for
patients with suspicion of balanced CAD. There are no
studies evaluating the benefit of noninvasive stress tests
or cardiovascular revascularization in patients with
MINS. The clinical expertise of a multidisciplinary team
should guide the investigations depending on patients’
clinical presentation and preferences.
3. Periodic follow-up, up to 1 year or longer, should be
considered, especially in the presence of high-risk
features, given the high-risk of cardiovascular events
and mortality in the first year.
Perioperative Atrial Fibrillation: Clinical Scenario
Mrs. M. is a 71-year-old woman undergoing laparotomic resection
of a large left ovarian cystic mass (benign pathology). She has
hypertension (on amlodipine 10 mg daily), obesity (BMI 38 kg/m
2
),
and obstructive sleep apnea (compliant to CPAP). She does not
have any history or symptoms of cardiac disease. Her preoperative
NT-proBNP is 550 mg/L. Intraoperatively, her systolic BP was
85 mmHg for 5 min, which improved with intravenous fluids.
After surgery, because of the intraoperative hypotension and
elevated preoperative NT-proBNP, the anesthetist recommended
cardiac monitoring. On postoperative day 1, the monitor shows
atrial fibrillation (AF) with a ventricular rate of 130–140 beats/
min. She is asymptomatic; her BP and oxygen saturation is
normal. She receives one dose of intravenous metoprolol; 5 mg.
Rate control is achieved followed by spontaneous conversion to
sinus rhythm the next day. She is worked up for persistently high
white blood cell count and a urine culture is positive for E. Coli.
After treatment of the urinary tract infection and postoperative
cardiac monitoring for 5 days, she is discharged with a scheduled
follow-up with surgery and perioperative medicine.
What Is POAF and How Frequent Is It done in Noncardiac
Surgery?
AF is the most common sustained cardiac arrhythmia in
nonsurgical adult populations. POAF comprises AF occurring
during an ongoing surgery or in the immediate postoperative
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Postoperative troponin elevation during or within 30 days of noncardiac surgery
Clinical evaluation -rule out non acute ischemic causes
(e.g., sepsis, pulmonary embolism, chronic troponin elevation)
• Monitor for ischemic symptoms (e.g. chest pain, shortness of breath)
• Review intraoperative hemodynamics (check for significant hypotension, severe hypertension, persistent tachycardia or bradycardia, intraoperative bleeding)
• Review CV risk factors, previous CV events, previous Echocardiograms, stress tests and coronary angiogram (review anatomy andrecent procedures –PCI, CABG)
• Monitor vital signs (BP, HR, oxygen saturation), bleeding and volume status
• Perform Electrocardiogram (ECG) on first assessment. Repeat ECG if chest pain, and at least daily until troponin peak. Consider telemetry.
• Monitor troponin until peak
• Screen for CV risk factors and smoking status -consider Lipid profile, HbA1C
If non acute ischemic cause identified
treat underlying etiology for troponin
elevation
Postoperative troponin elevation attributed to ischemia - MINS
STEMI
Follow specific CCS
guidelines
Consider Cardiology
consultation and
urgent cardiac
angiogram
MINS with no high-risk features
• Consider outpatient Echocardiogram and/or non-invasive
stress test
• RCRI ≥ 1, Age ≥ 65 or 45-64 years old with significant CV disease, or NT-probnp 200 or greater, or BNP 92 or greater
MINS with high risk features**
• In-patient Echocardiogram
• Consider involving Cardiologist and the surgical team for a multidisciplinary
team decision for invasive versus non-invasive inpatient stratification
• ECG in the PACU
• Troponin measurement daily for 48-72 hours
• If no ongoing major bleeding and hemoglobin stable, consider starting low dose ASA 81 mg PO daily and Dabigatran 110 mg PO twicedaily as soon as the surgeon is comfortable
from a bleeding point of view
• Consider high dose statin and other therapies including a Beta-blocker if elevated HR, ACE inhibitor if BP stable with no hypotension
• Prescribe and educate on use of nitroglycerin spray PRN if chest pain
• Offer pharmacologic therapy for smoking cessation if needed
• Consider outpatient Echocardiogram and/or non-invasive stress test
• Educate on the need for ER visit if alarm symptoms (e.g., prolonged or rest chest pain, presyncope, syncope, shortness of breath, tachycardia, bradycardia, or severe hypotension)
• Outpatient follow-up in clinic within 2-4 weeks
Figure 1. Algorithm on how to manage patients with myocardial injury after noncardiac surgery (MINS).
* NT-proBNP ≥200 mg/L suggested threshold according to Duceppe E, Patel A, Chan M, et al. Preoperative N-Terminal Pro–B-Type Natriuretic Peptide and Cardiovascular Events After
Noncardiac Surgery: A Cohort Study. Annals of Internal Medicine 2020; 172:96–104. ** Known high-risk anatomy, persistent chest pain, signs of CHF, ECG with high risk ischemic findings,
hemodynamic instability. Abbreviations: ACE: Angiotensin-converting enzyme; ASA: aspirin; BP: blood pressure; CABG: coronary artery bupass graft; CCS: Canadian Cardiovascular Society; CHF:
congestive herat failure; CV: cardiovascular; ER: emergency room; HR: heart rare; NT-pro-BNP: N-terminal prohormone of brain natriuretic peptide; PCI: percutaneous coronary intervention;
PO: per oral; STEMI: ST elevation MI.
period. While patients with known AF (permanent or paroxysmal)
might experience AF in the perioperative setting, in this review
we refer to POAF as new onset, if not otherwise specified. After
cardiac surgery, 20–50% of patients develop POAF
24
; the incidence
of POAF after noncardiac thoracic surgery can also be as high as
30%, depending on the type of, and the reason for, the procedure.
25
The reported incidence of POAF in noncardiac, nonthoracic
surgery ranges between <1 and >20%, with higher estimates in
abdominal surgery (>10%) than in total joint replacements (5%).
The average incidence in the largest nonselected noncardiac
surgery cohorts is 3%.
26–28
POAF typically occurs during the
first 4 postoperative days. However, true incidence and time
distribution of POAF is likely underestimated, as continuous
postoperative ECG monitoring is rarely employed.
Why Does POAF Occur after Noncardiac Surgery?
The pathophysiology of POAF has not been fully understood,
and multiple mechanisms might play a role, including surgery
itself, which is associated with the activation of the sympathetic
nervous system. Many events in the perioperative period, such
as hypotension, hypoxia, hypovolemia or hypervolemia, anemia,
metabolic imbalances, trauma, infection, and pain, can also trigger
POAF through sympathetic activation or other mechanisms;
these factors are more likely to result in POAF in patients with
preexistent cardiac disease.
29
Patient- and surgery-related risk
factors that are associated with an increased risk of POAF include
older age, male sex, obesity, congestive heart failure, signs of left
atrial cardiomyopathy, thoracic surgery, longer procedures, and the
use of inotropes.
29,30
Elevated preoperative BNP or NT-proBNP
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were found to be associated with POAF after thoracic surgery.
31,32
More recently, in a sub-analysis of the VISION study including
9,789 patients, preoperative NT-proBNP values improved the
prediction of POAF risk over conventional prognostic factors
across different noncardiac surgeries. Compared with a reference
NT-proBNP measurement set at 100 ng/L, adjusted ORs for
the occurrence of POAF were 1.31 (95% CI 1.15–1.49) at 200
ng/L, 2.07 (95% CI 1.27–3.36) at 1500 ng/L, and 2.39 (95% CI
1.26–4.51) at 3000 ng/L.
33
What Is the Clinical Relevance of POAF?
Most patients with POAF convert to sinus rhythm spontaneously
and many POAF episodes are asymptomatic and remain
undetected. However, POAF can also result in hemodynamic
instability that requires immediate intervention. POAF has been
associated with prolonged hospital stay and an increased risk of
perioperative complications, including infections, stroke, and
in-hospital mortality.
27,34–36
POAF that occurs after cardiac surgery is associated with a
fivefold increased risk for recurrent AF in the next 5–6 years.
37,38
By comparison, the risk of recurrent AF after noncardiac surgery is
less studied but is likely to be similar after a long-term follow-up.
39
Patients who develop POAF after noncardiac surgery are at an
increased risk for stroke, death, and other cardiovascular events
at 1 year after surgery.
40–43
A post hoc analysis combined data
from the PeriOperative ISchemic Evaluation POISE-1
44
and
POISE-2 trials
45,46
and included 18,117 patients (mean age
69 years, 57.4% male) with, or at risk of, cardiovascular disease
who were undergoing noncardiac surgery and were not in AF
at the time of study enrollment. Compared to those without
POAF, patients with POAF had a higher incidence of stroke
1 year after surgery (5.58 vs. 1.54 per 100 patient years; aHR =
3.43; 95% CI: 2.00–5.90).
40
POAF was associated with increased
mortality (incidence 31.4 vs. 9.3; aHR = 2.5; 95% CI: 2.01–3.14)
and MI (incidence 26.2 vs. 8.23; aHR = 5.10; 95% CI: 3.91–6.64)
at 1 year. The long-term incidences of these adverse events are
comparable to those of patients clinically diagnosed with AF in
nonsurgical contexts.
30
It is still to be determined whether POAF of different durations
or timing of onset, and POAF clinically diagnosed versus detected
by continuous ECG monitoring, have a different prognostic value.
However, overall, the existing evidence underlines the clinical
significance of POAF as a perioperative event with short- and
long-term impacts.
How Can POAF be Prevented?
Existing evidence on perioperative pharmacological strategies to
prevent POAF is not definitive. Perioperative beta-blockers have
been shown to reduce POAF in noncardiac surgery
47
; however,
in the POISE-1 trial, metoprolol increased the incidence of death
and stroke 30 days after surgery.
44
Amiodarone has been showed
to be effective,
47
with lower cumulative doses likely to have a
better profile in terms of side effects.
48
Evidence on perioperative
statin and POAF prevention is less robust.
47,49
Perioperative
colchicine to prevent POAF in thoracic surgery is currently under
investigation (NCT03310125). Currently, there is no perioperative
pharmacological prophylaxis for POAF recommended for
every patient undergoing noncardiac surgery; a personalized
approach based on a cautious consideration of surgery-related
and patient-related risk factors is instead recommended.
48
Overall,
it is reasonable to expect that hemodynamics and laboratory
monitoring, in order to prevent or detect early and manage
possible triggers, will prevent POAF.
How Should POAF be Acutely Managed?
POAF should be acutely managed based on the same principles
of acute AF management in other contexts, adapted to patient
characteristics, patient preferences, and local protocols.
30,48
In
many cases, the rhythm disturbance will resolve with the resolution
of the precipitating trigger(s).
29
In hemodynamically unstable
patients, emergency electrical cardioversion is indicated. There
are no RCTs done in patients with POAF comparing rate versus
rhythm control, or different strategies for rate or rhythm control.
Given the high rate of spontaneous conversion to sinus rhythm
in POAF, it is reasonable to consider rhythm control only when
the patient is symptomatic, and/or when rate control is difficult
to achieve.
48
In the case of nonemergency cardioversion, peri-
procedural anticoagulation is recommended with the same rules
as in AF diagnosed in a nonoperative setting.
48
Rate control (target
heart rate <100 beats/min) could be achieved with beta-blockers
(preferable in case of known CAD or reduced ejection fraction),
nondihydropyridine calcium channel blockers, or digoxin.
48
In
patients with preexisting AF, or at high risk of POAF, we suggest
telemetry monitoring at least for the first 24–48 h after surgery
to detect episodes of AF at risk of hemodynamic compromise
and to intervene in a timely fashion (Figure 2).
Should Patients with POAF Receive Long-Term Anticoagulation?
The adoption of long-term oral anticoagulation (OAC) remains
controversial. The high long-term risk of stroke after POAF, like
that associated with nonoperative AF, suggests that patients with
POAF could benefit from long-term OAC. In a large Danish
cohort study, long-term benefit of OAC, initiated within 30
days from discharge, was similar between patients with POAF
after noncardiac surgery (HR 0.52; 95% CI 0.40–0.67) and
matched patients diagnosed with nonoperative AF (HR 0.56;
95% CI 0.51–0.62).
50
OAC therapy during follow-up was also
associated with a significantly lower risk of all-cause mortality
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Borges et al.
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in both patients with POAF and nonoperative AF. Alternatively,
another large retrospective cohort study, using data from the
Quebec Hospital Discharge Database, did not show similar
benefits.
51
Overall, cautious interpretation is needed given the
observational nature of this evidence. The ongoing ASPIRE-AF
(NCT03968393) randomized trial will inform the long-term
benefits and risks of OAC in POAF after noncardiac surgery.
In the meantime, current guidelines suggest that long-term
OAC therapy should be considered in patients at risk for
stroke with POAF after noncardiac surgery, accounting for the
anticipated net clinical benefit of OAC therapy and informed
patient preferences.
48
Neither CHADS
2
nor the CHA
2
DS
2
-VASc
score (congestive heart failure, hypertension, age ≥75 years,
diabetes mellitus, stroke/transient ischemic attack, vascular
disease, age 65–75 years, and sex)
52,53
has been validated in
surgical populations, but their use for long-term stroke risk
prediction in patients with POAF seems reasonable.
29,54
We
suggest performing an echocardiogram to evaluate the presence
of structural or functional abnormalities that could increase the
risk of recurrences and/or of cardioembolic events. In most of the
cases, the echocardiogram can be performed in the outpatient
setting, unless the patient in-hospital course suggests otherwise
(e.g., POAF associated with hemodynamic instability, symptoms
of congestive heart failure, or significant myocardial ischemia).
Knowing that the patient is having arrhythmia recurrences, even
if asymptomatic, through extended ECG Holter monitoring (i.e.,
14 days), once the patient is discharged, can also help with the
decision about OAC. Patient baseline bleeding risk should also
play an important role in the decision. Bleeding risk scores (e.g.,
HAS-BLED) developed in the nonoperative setting
55
have not
been specifically validated in the setting of initiating OAC for
AF diagnosed in the perioperative setting; however, they can
provide a reasonable guidance on the long-term risk of bleeding
with OAC. In the specific case of POAF, considerations about
the bleeding risk related to the type and reason of the recent
surgery should be discussed with the surgeon, in relation to the
timing of OAC initiation.
How Do We Manage Our Clinical POAF Case?
Mrs M. is seen by the perioperative medicine service at 1
month after surgery. She reports to be asymptomatic since
discharge. In clinic, BP is 165/88 mmHg, heart rate is 88 beats/
min (regular), and oxygen saturation is 94% on room air. ECG
shows sinus rhythm. Echocardiogram shows mild concentric
left ventricular hypertrophy; preserved global and regional left
ventricular contractility (ejection fraction 55%); indeterminate
diastolic filling pattern; both atria are moderately dilated; and
no valve disease is seen. Although ongoing infection and the
intraoperative hypotension were possible triggers of the episode
of POAF, she presents predisposing clinical characteristics
(obesity, hypertension, cardiac remodelling, and enlarged left
atrium), which could also increase the risk of AF recurrences.
Her CHA
2
DS
2
-VASc score is 3 (3.2% risk of stroke per year).
Long-term OAC is started in agreement with the patient after
discussing potential benefits of stroke prevention and bleeding
risk (HAS-BLED score 2 points; 1.88–3.2% risk of major bleeding
Possible triggers
(hemodynamics, anemia, metabolic
imbalances, pain)
Patient-and surgery-related risk factors for
atrial fibrillation
(past medical history, biomarkers,
echocardiogram)
Impact on hemodynamics, patient
signs and symptoms
Cardio-embolic and bleeding risk
factors
Patient’s values and preferences
• Prevention
• Acute Management
• Long term management of hemodynamics and
symptoms
• Long-term anticoagulation
Figure 2. Factors and strategies to consider in the management of perioperative atrial fibrillation (POAF).
Canadian Journal of General Internal Medicine
24 Volume 16, Special Issue 1, 2021
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CJGIM_1_2021_176993.indd 24CJGIM_1_2021_176993.indd 24 3/22/21 6:28 PM3/22/21 6:28 PM
per year). Initiation of ACE inhibitor, optimal BP control, and
weight reduction is also recommended.
Disclosures
All authors declare no competing interests.
Funding Statement
Dr. Flavia Kessler Borges holds a McMaster University Department
of Medicine Career Research Award. Dr Sandra Ofori holds a
Michael G. DeGroote Fellowship Award for Clinical Research.
Dr. Maura Marcucci holds a McMaster University Department
of Medicine Career Research Award and a PSI Foundation Mid-
Career Clinical Research Award.
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