Case report

Elective surgery days after myocardial infarction: clinicaland ethical considerations

Pei-Lee Ee MD (Resident), Paul M. Kempen MD, PhD (Associate Professor)*

Department of Anesthesiology, University of Pittsburgh Medical Center, Presbyterian University Hospital,

Pittsburgh, PA 15213, USA

Received 4 February 2005; accepted 7 December 2005

0952-8180/$ – see front matter D 2006

doi:10.1016/j.jclinane.2005.12.002

* Corresponding author. Tel.: +1 412

E-mail address: kempenpm@anes.u

Keywords:Ethics;

Myocardial infarction;

Perioperative b-blockade;Guidelines;

Cardiac;

Anesthesia;

Complication

Abstract We present an unusual case of verified myocardial infarction without surgery. Successful

elective lumbar spine surgery was performed 4 days post–myocardial infarction during perioperative

b-blockade, after cardiology evaluation recommended surgery without further evaluation. Clinical and

ethical considerations are discussed.

D 2006 Elsevier Inc. All rights reserved.

1. Introduction

Preoperative coronary events including new ischemia,

infarction, or revascularization introduce a high- and

intermediate-risk period of 4 to 6 weeks and 3 months,

respectively [1]. The generally accepted ACC/AHA guide-

lines specify recent myocardial infarction (MI) within the

past month to represent a major predictor of perioperative

risk. Current recommendations defer elective procedures

during these periods because of the associated increased

risk. Although perioperative MI is a well-described

complication with significant morbidity/mortality, MI sec-

ondary to anesthesia induction alone is not. For the first

time, the clinical course of a 57-year-old woman is

presented who (1) experienced severe ischemic electrocar-

diographic (ECG) changes upon anesthetic induction; (2)

was diagnosed with extensive non–ST-elevation myocardial

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647 5909; fax: +1 412 647 0342.

pmc.edu (P.M. Kempen).

infarction (NSTEMI) within 24 hours of anesthesia without

surgery; and (3) after extensive cardiac evaluation confirm-

ing acute infarction and minimal hemodynamic compro-

mise, was referred for immediate elective surgery 4 days

post-MI during perioperative b-blockade and aspirin

therapy. The specific factors leading to surgery immediately

postinfarction, as well as the implications and consider-

ations in performing elective surgery after such a short

interval, are presented.

2. Case report

A 57-year-old woman with back pain of 2 years’

duration, presented for a reexploration and L5-S1 micro-

discectomy. Medical history was significant for a 45 pack-

year smoking history, hypertension, hyperlipidemia, and

gastroesophageal reflux disease. Medications include hy-

drochlorothiazide, atorvastatin, estradiol, paroxetine, ome-

prazole, clonazepam, and hydrocortisone. Her physical

examination was unremarkable, including heart rate of

Journal of Clinical Anesthesia (2006) 18, 363–366

P.-L. Ee, P.M. Kempen364

80 beats per minute (bpm), blood pressure of 136/84 mmHg,

and room air oxygen saturation of 99%. Laboratory analysis

and a preoperative ECG were within normal limits.

After sedation with fentanyl 100 lg and midazolam

2 mg, rapid-sequence induction using propofol 150 mg and

succinylcholine 120 mg was instituted, followed by

rocuronium 20 mg, desflurane 2%, and 50% nitrous

oxide/oxygen. While preparing for prone positioning,

ventricular bigeminy, significant ST-segment elevation in

both monitored leads II and V, blood pressure of 210/134,

and a heart rate of 130 bpm were noted. While intravenous

metoprolol administration rapidly resolved all abnormali-

ties, surgery was deferred pending cardiac evaluation. The

patient was transferred to the postanesthesia care unit

maintaining propofol sedation until residual muscle relax-

ant effects dissipated. An ECG was now obtained

demonstrating no changes from preoperative baseline, and

cardiology consultation recommending extubation and

transfer to a monitored floor occurred. The patient

remained stable. The troponin I/creatine kinase–MB levels

were found to be 4.84 ng/mL (normal value 0.08 ng/mL)

and 10.4 ng/mL (normal b7 ng/ml if CPK b200 IU/L,

which it was at 106 IU/L) the next morning. These

represented the peak detected levels, declining to 2.54

and 8.9 ng/mL, respectively, 6.5 hours later. Repeat

ECG obtained 4 hours after the initial abnormal troponin

level was detected demonstrated sinus rhythm with T-wave

inversion in leads II, III, aVF, and V3 through V6.

Anterolateral and inferior NSTEMI was diagnosed. Ther-

apy including aspirin, intravenous heparin, and metoprolol

was instituted. A left heart catheterization performed the

next day showed no significant disease throughout the left

coronary artery. The right coronary artery was dominant,

with mild diffuse disease. Left ventriculography showed

anterior and apical wall hypokinesis and ejection fraction

(EF) of 45% to 50%. An adenosine thallium stress test

to differentiate NSTEMI vs a reversible ischemic troponin

leak was obtained, demonstrating anteroapical subendocar-

dial infarction without redistribution abnormalities. Cardi-

ology consultants specifically recommended: bPatient may

go to surgery without further testing, when surgeons are

ready, tomorrow if scheduled.Q No specific postoperative

restrictions, additional use of nonstandard intraoperative

monitors, or significant perioperative risk delineation was

suggested as (1) no significant fixed vascular lesions were

noted; (2) overall myocardial function was preserved;

(3) no transmural lesion was identified; (4) no arrhythmia

had been noted on continuous ECG monitoring, while

provocative testing for vasospasm was undesirable in the

face of acute MI; and 5) no statistical data were available

or offered regarding perioperative morbidity/mortality

in this previously unreported situation. The patient’s

metoprolol had been increased on day 3 due to tachycardia

noted on ECG and to provide effective perioperative

b-blockade along with low-dose aspirin. Smoking cessation

was instituted.

Now 3 days post-MI, troponin I level was last noted to

be abnormal and declining to 0.17 ng/mL, as was expected

to be with a singular event occurring within 24 hours of

anesthetic induction. After review of her chart, an

extended discussion with the patient occurred. She was

informed of the pertinent risks of proceeding at this time,

including death and reinfarction, with specific emphasis

that national ACC/AHA guidelines recommend to defer

surgery at least 6 weeks. The patient insisted on pro-

ceeding with her elective surgery at this time because

she had been cleared by the cardiologists, surgery was

scheduled, she had made significant efforts to dedicate

this period for surgery, and she had significant, unrelent-

ing pain. Standard consent forms and an additional note

signed by the patient and providers were placed in the

chart documenting these discussions, anesthetic recom-

mendations against surgery, and also the patient’s ulti-

mate decision.

Immediately preoperatively, the patient’s heart rate was

acutely reduced from 85 to 70 bpm with additional

titration of 12.5 mg IV metoprolol. General anesthesia

was induced using IV etomidate 22 mg with additional

8 mg before intubation. Muscle relaxation was provided by

vecuronium one mg (priming) plus 7 mg. She also

received fentanyl 50 lg. A noticeably slow onset of action

was evident for etomidate. Following the etomidate with

15 mL of saline flush, the patient remained conscious for

approximately 30 seconds. Subsequently, vecuronium

relaxation occurred after 4 minutes, in spite of a priming

dose of one mg 2 to 4 minutes before the etomidate. This

led to an additional etomidate 8 mg IV dose in anticipation

of possibly significant emergence from the original

induction dose at intubation. Isoflurane and 50% nitrous

oxide in oxygen were administered to maintain anesthesia.

An arterial catheter was placed after the slow onset of

agents and a trend toward hypotension became evident.

Intracardiac catheterization and transesophageal echocardi-

ography were not used because of risk/benefit consider-

ations and stabile overall hemodynamics persisting after

prone positioning. After prone positioning, the patient

required a phenylephrine infusion between 0.2 and

0.5 lg/kg per minute to maintain adequate mean arterial

blood pressure at 90 to 100/55 mmHg to 65 mmHg and

with heart rate at 60 F 5 bpm throughout. Glycopyrrolate

0.2 mg was administered in 0.1 doses to raise the heart

rate to 65 from 55 bpm to minimize the need for increased

phenylephrine administration. Intravenous morphine was

administered anticipating the end of surgery and postop-

erative pain. The patient was extubated immediately at the

end of the procedure without complication. No ECG

changes were noted intraoperatively in leads II or V. A

postoperative 12-lead ECG showed sinus rhythm at

62 bpm, unchanged from preoperative levels. Troponin

levels were not obtained postoperatively. The patient was

observed overnight and discharged home the next day

without further complications, per recommendations of the

Elective surgery days after myocardial infarction: clinical and ethical considerations 365

neurosurgical and cardiac services, to the care of her

family in a community with a university hospital.

3. Discussion

In the past 2 decades, improvements in cardiac manage-

ment have decreased the recommended waiting period after

MI for noncardiac surgery from 6 months to as little as

4 weeks in selected patients after minimal infarction,

without residual angina and exhibiting good functional

status. Patients with major risk factors include those with

recent MI (b4-6 weeks), unstable or severe angina (class III-

IV), ongoing ischemia after MI, congestive heart failure, or

malignant arrhythmias [1]. These patients with such major

risk factors may have as high as a 5-fold increased

perioperative risk [1]. A patient with a large infarction,

residual symptoms, and an EF below 35% has a high

probability for further cardiac events, even 6 months after

the infarction [1]. As such, the risk after previous infarction

may be related less to the age of the infarction than to

ventricular function and the amount of myocardium at risk

of further ischemia [1]. Our patient was deemed by the

cardiac consultants to be a low risk for further events during

b-blockade.Caring for patients with significant cardiovascular

disease is ubiquitous in modern anesthesia practice. Special-

ists are consulted for cardiac evaluation and to facilitate the

determination of operative readiness [2]. Research focuses

on preoperative evaluation with risk stratification of

patients, so that morbidity and mortality can be minimized,

as a member of a group, rather than as an individual [3]. Our

patient was uniquely referred as optimal for surgery

immediately post-MI and in apparent conflict with recom-

mended guidelines. In spite of specific cardiologist involve-

ment and recommendation for perioperative b-blockade,effective blockade with depression of heart rate into the

60 bpm range at rest did not occur until last-minute, and may

have significantly reduced inotropy in this setting [4,5]. The

anesthesiologist still must ultimately make specific recom-

mendations regarding anesthetic risk in consideration of

published guidelines, known risk/benefit ratios, and the

patient’s best interests. However, the risk is not always

clearly quantifiable. Risk belongs to the patient alone. After

informed consent is provided, ethical considerations place

the patient’s wishes paramount (Guidelines for the ethical

practice of anesthesiology. American Society of Anesthesi-

ologists House of Delegates, October 2003. http://www.

asahq.org/publicationsAndServices/standards/10.pdf).

This patient was extensively evaluated, informed, and

optimized for surgery by multiple consultants in a tertiary

care center, who advised the patient to proceed with surgery,

with the exception of the anesthesiologist. With the patient’s

desire to proceed immediately and with presentation of

specific and directly opposing recommendations by the

anesthesia providers, ethical guidelines take precedence [6].

Meeting the patient for the first time only immediately

before the scheduled surgery, one can only with great

difficulty establish an interpersonal rapport with the patient,

which might dissuade the patient from proceeding with

surgery, brecommendedQ by the already familiar surgeon and

cardiac consultants. It is not in the patient’s best interests to

bbe placed in the middleQ of a difference of specialists’

opinions. However, clear provision of available pertinent

dissenting information in an honest, nonthreatening, and

noncoercive manner becomes basic to the ethical process of

informed consent. Presentation of general guidelines may

ineffectively sway a patient away from recommendations to

proceed based on their personal physiology, obtained over

days and interpreted by familiar cardiac specialists in a

positive fashion. Finally, as a senior university-based

anesthesiologist, further referral or provision of substitute

providers (ie, alternate, more eager, or bbetterQ providers)

rapidly become nonoptions at the start of a busy surgical day

and in spite of any personal trepidation.

However, and in retrospect, several considerations deserve

mention and support adherence to prevailing guidelines and

in spite of the positive outcome. Although the EF was

described on ventriculogram as 45% to 50% early post-MI,

considerable b-blockade was introduced subsequently and

immediately preoperatively, which may have further com-

promised hemodynamics below previously determined val-

ues. The circulation time appeared significantly prolonged

beyond expectations at induction and blood pressure support

was required intraoperatively. Although an unusual step,

repeat examination using echocardiography immediately

preoperatively might have disclosed significant additional

interval compromise. This was not considered and knowl-

edge of these effects might have altered consultant recom-

mendations, patient decision, and anesthetic plans, resulting

in postponement of operation. The apparent signs of cardiac

depression noted only intraoperatively may have been due to

invalid interpretations of individual preoperative studies, the

increase in interval b-blockade, natural history of the

infarction, or a combination of these factors.

The absence of significant coronary stenosis or ischemia

detected in vessels supplying the antero-apical-inferior wall

(site of infarction) via angiogram or single-photon emission

computed tomography scan also raised questions regarding

validity of individual study results vs vasospasm, transient

ischemic acute coronary syndrome, or simply extreme

hypertensive tachycardia, as specific causative mechanisms

of subendocardial myonecrosis. Although calcium channel

blockers may have been more specific than b-blockers in

treating vasospasm, the strong, specific indication for

perioperative b-blockade prevailed [7,8]. Aspirin therapy

was specifically maintained perioperatively without signif-

icant detriment to hemostasis. Anesthetic care typically is

terminated upon discharge from the PACU and the decision

to discharge the patient remains the prerogative of the

surgeon and his postoperative medical consultants. With a

benign postoperative course, discharge the next morning

P.-L. Ee, P.M. Kempen366

followed typical surgical patterns and preoperative cardiac

recommendations, which imposed no restrictions. Standard

care in this unusual patient reflected the modern paradigm

for cost containment and using confirmed ongoing family

support in a community with immediate tertiary care access.

We describe for the first time successful elective micro-

discectomy 4 days post-MI, with unique preoperative

evaluation/preparation and imposing ethical factors. This

is the first report of a confirmed perianesthetic NSTEMI in

the absence of fixed coronary stenosis, proceeding to

surgery after a 4-day interval, without incident.

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