CARDIAC RISK IN NON-CARDIAC SURGERY


The insults of surgery
Scoring systems to estimate cardiac Risk in non-cardiac surgery
Specific cardiovascular conditions

Chronic cardiac meds--Perioperative management
Screening for Coronary Artery Disease and other cardiac disease preoperatively
(separate page)
Medications for prophylaxis against perioperative cardiac events
        Beta-blockers
Intraoperative interventions to improve perioperative outcomes
Screening for and management of postoperative Myocardial Infarction
Preoperative treatment of CAD with revascularization 

I. The insults of surgery

  1. Hypotension
  2. Hypoxemia
  3. Hypothermia
  4. Anemia
  5. Postoperative pain
  6. General & spinal anesthesia generally equal risk re: cardiac complications

II. Scoring systems to estimate cardiac Risk in non-cardiac surgery

  1. Goldman Index (aka "Cardiac Risk Index"; N Engl J Med. 1977;297:845-850)
Finding Points
MI within 6mos 10
Age > 70y 5
S3 or JVD 11
Sig. aortic stenosis 3
Rhythm other than SR or SR w/APC's on last EKG 7
5 PVC's/min anytime before surgery 7
Poor general medical status 3
Intraperitoneal, intrathoracic, or aortic operation 3
Emergency operation 4

 

Class Point Prob. of life-threatening complications
I 0-5 0.7
II 6-12 5
III 13-25 11
IV >25 22
  1. Eagle criteria: similar to Goldman's but specifically for evaluating cardiac risk in vascular surgery patients
  1. " Eagle factors": >70yo, h/o angina, significant Q's, CHF, DM needing Rx
  2. Risk of perioperative MI
  1. "Low risk": if 0 factors, risk = 3.1%; no additional pre-op testing needed
  2. "Intermediate risk: if 1-2 factors, risk = 15%; noninvasive testing with angio if inducible ischemia
  3. "High risk: if > 2 factors, risk = 50%; go straight to angio
  4. If angio shows l. main disease, etc., consider angioplasty or CABG before planned surgery; if serious lesions not amenable to either, consider foregoing surgery.
  1. "Revised Cardiac Risk Index"--Predicts cardiac complications (MI, pulmonary edema, VFib, cardiac arrest, or complete heart block) in major nonemergent noncardiac surgery in pts > 50yo more accurately than Goldman or Detsky (Circ. 100:1043, 1999--JW)
  1. The number of the following risk factors is tallied; the incidence of perioperative cardiac complications in the study above was 0.5%, 1.3%, 3.6%, and 9.1% for 0 (Class I), 1 (Class II), 2 (Class III), or > 2 (Class IV) of these, respectively
    1. "High-risk" surgery (intraperitoneal, intrathoracic, or suprainguinal vascular)
    2. History of ischemic heart disease
    3. History of CHF
    4. History of cerebrovascular disease
    5. Insulin therapy
    6. Serum Cr > 2.0 mg/dL

III. Specific cardiovascular conditions

  1. Coronary Artery Disease
  1. Chronic stable angina needs no further pre-op testing
  2. See also under Medications for prophylaxis against perioperative cardiac events below
  3. Post-MI patients--"If a recent stress test does not indicate myocardium at risk, the likelihood of reinfarction after noncardiac surgery is low" but recommend waiting 4-6wks after MI to perform elective surgery (2002 ACC/AHA guidelines)
  1. Cardiac Arrhythmias
  1. "Asymptomatic ventricular arrhythmias, including couplets and nonsustained ventricular tachycardia, were not associated with an increase in cardiac complications after noncardiac surgery...However, physicians should have a low threshold to institute prophylactic betablocker therapy in patients at increased risk of developing a perioperative or postoperative arrhythmia." (2002 ACC/AHA guidelines)

  2. Minor conduction disturbances e.g. BBB or 1' AVB usually don't merit further workup (ibid.)

  3. Patients with implanted ICDs or pacemakers should have their device evaluated before and after surgical procedures (ibid.)

  4. Supraventricular Arrhythmias appearing intra-operatively or postoperatively—Control heart rate w/digitalis, beta-blockers, or Ca-blockers. Dig is the least effective; beta blockers are the most effective (and have been shown to accelerate the conversion to sinus rhythm c/w diltiazem)

  5. Ventricular Arrhythmias appearing intra-operatively or postoperatively—Require therapy only if ass'd w/hemodynamic compromise or ongoing or threatened myocardial ischemia or LV dysfunction.  Frequent PVCs or asymptomatic nonsustained Ventricular Tachycardia are not ass'd with an increase in nonfatal MI or cardiac death, but should provoke a search for underlying cardiopulmonary disease, drug toxicity, or metabolic derangements (ibid.)

  6. Sustained or symptomatic Ventricular Tachycardia should be suppressed preoperatively with intravenous lidocaine, procainamide, or amiodarone (ibid.)

  1. Congestive Heart Failure
  1. "Every effort must be made to detect unsuspected heart failure by a careful history and physical examination." (2002 ACC/AHA Guidelines)
  2. The 2002 ACC/AHA guidelines recommend evaluating LV function (e.g. w/echocardiography) as "Class I" for pts with poorly-controlled CHF unless known to have severe LV sydfunction; "Class IIa" with prior CHF and dyspnea of unknown origin
  1. Peripheral Arterial Disease
  1. More than 30% have coexistent CAD, often silent due to claudication limiting activity
  1. Valvular heart disease
  1. Clinical experience indicates that [such] patients  severe enough to warrant surgical treatment should have valve surgery before elective noncardiac surgery." (2002 ACC/AHA guidelines)
  2. "Patients with severe mitral or aortic stenosis who require urgent noncardiac surgery may benefit from catheter balloon valvuloplasty as a temporizing step." (ibid.)
  1. Aortic Stenosis
    1. Ass'd with the highest risk of all valvular disease for noncardiac surgery
    2. "If...severe and symptomatic...[the patient should undergo] aortic valve replacement before elective but necessary noncardiac surgery...On the other hand, in patients with severe aortic stenosis who refuse cardiac surgery or are otherwise not candidates for aortic valve replacement, noncardiac surgery can be performed with a mortality risk of approximately 10%" (2002 ACC/AHA guidelines)
  1. Mitral Stenosis
    1. If mild-moderate, avoid tachycardia perioperatively because reduction in diastolic filling with tachycardia can lead to pulmonary congestion
    2. "Preoperative surgical correction of mitral valve disease is not indicated before noncardiac surgery, unless the valvular condition should be corrected to prolong survival and prevent complications, unrelated to the proposed noncardiac surgery (2002 ACC/AHA guidelines)
  1. Aortic Regurgitation

    1. May require antibiotic prophylaxis for Endocarditis

    2. Avoid volume overload

  1. Mitral Regurgitation

    1. May require antibiotic prophylaxis for Endocarditis

    2. With severe MR, "may benefit from afterload reduction and administration of diuretics to produce maximal hemodynamic stabilization before high-risk surgery.  Occasionally this therapy can best be accomplished by treatment in an intensive care unit with a catheter to monitor pulmonary artery pressure." (2002 ACC/AHA guidelines)

  1. Hypertension
    1. BP < 180/110 is not independently ass'd with perioperative cardiovascular complications but may be at higher BP's  (2002 ACC/AHA guidelines)
    2. Should try to decrease BP below 180/110 before surgery (Per JNC VI; see link above for more detail)
    3. "In patients with severe hypertension, particularly of recent onset, it may be appropriate to delay elective surgery while the patient is evaluated for curable causes of hypertension" i.e. hyperaldosteronism, renal artery stenosis, pheochromocytoma, etc. (2002 ACC/AHA guidelines; see above)

    4. See notes in "Basic Considerations" regarding avoiding Ca-channel blockers because of bleeding risk
    5. Exercise caution in withdrawing beta-blockers and clonidine b/c of potential rebound hypertension.

IV. Chronic cardiac meds--Perioperative management

  1. Most should be continued up to surgery; can give on morning of surgery with sip of water even if NPO
  2. Clonidine and beta-blockers have withdrawal sd's
  3. d/c ASA 7d ahead
  4. d/c NSAIDs 2-4d ahead

V. Screening for Coronary Artery Disease and other cardiac disease preoperatively--This section includes the ACC/AHA algorithm for determining appropriate preoperative cardiac workup

VI. Medications for prophylaxis against perioperative cardiac events

  1. Beta-blockers
    1. 112 patients w/risk factors for cardiac disease scheduled for vascular surgery and with an abnormal (NOT severely so) dobutamine stress echocardiogram randomized (unblinded) to bisoprolol 5-10mg PO QD vs. placebo perioperatively. Cardiac death (3.4% vs. 17%) and nonfatal MI (0% vs. 17%) sig. lower for bisoprolol vs. placebo groups, respectively.  Pts began taking bisoprolol a mean of 37 days before surgery (NEJM 341:1789, 1999)
    2. The Multicenter Study of Perioperative Ischemia Research Group randomized 200 patients undergoing noncardiac surgery to atenolol (IV pre- & post-op and then 50-100mg/d PO until discharge) vs. placebo.  About 40% had known CAD; the rest had 2 or more risk factors for CAD.  No difference in perioperative MI or death but sig. fewer episodes of ischemia on continuous monitoring (24% vs. 39%) in the atenolol group. Also, sig. lower mortality @ 6mos (1% vs. 10%) and 2y (10% vs. 21%). Did not control for other medications given either before or after surgery; ACE inhibitor and beta-blocker use preoperatively differed significantly between the study groups. (NEJM 335:1713, 1996--JW)
    3. In a meta-analysis of 22 randomized studies of beta-blockers vs. placebo in 2,437 pts undergoing non-cardiac surgery, there was no sig. diff. in various individual outcomes at 30d, but among 8 trials which included pts who had major cardiovascular events, incidence of (cardiovascular death, nonfatal MI, or nonfatal cardiac arrest) was sig. lower with beta-blockers (RR 0.44) (BMJ 331:313, 2005--JW)
    4. In a study in 921 pts with DM > 40yo undergoing noncardiac surgery randomized to metoprolol (starting prior to surgery and continuing for 8d or until discharge) vs. placebo, there was no sig. diff. in 30d or 180d incidence of (death, MI, unstable angina, or heart feailure) ("DIPOM" Trial; BMJ 332:1482, 2006--JW)
    5. In a study in 496 pts undergoing abdominal aortic or peripheral vascular surgery randomized to metoprolol (starting prior to surgery and continuing x 5d or until discharge) vs. placebo, 30d incidence of (cardiac death, MI, unstable angina, heart failure, or dysrhythmias requiring treatment) was not sig. diff. in the two groups ("Metoprolol after Vascular Sugery" ("MaVS") Trial; Am. Heart J. 152:983, 2006--JW)
    6. In a study in 8,351 pts > 45yo undergoing noncardiac surgery with EITHER (h/o CAD, CVA, or PVD) or recent hospitalization for heart failure or undergoing major vascular surgery or (3 of seven other specified risk criteria) randomized to metoprolol 100mg extended-release x 1 2-4h prior to surgery and postoperatively 200mg QD x 30d vs. placebo, 30d incidence of (cardiovascular death, nonfatal MI, or nonfatal cardiac arrest) was sig. lower with metoprolol, but overall mortality was sig. higher (3.1% vs. 2.3%) ("POISE" trial; Lancet 371:9627, 2008-JW)
    7. In a study in 1,066 intermediate-risk pts (estimated risk for perioperative cardiovascular event) 1%-6% scheduled for elective noncardiac surgery randomized to bisoprolol starting @ 2.5mg/d and titreated to HR 50-70/min and SBP > 100 mm Hg vs. no bisoprolol starting 1mo before surgery, 30d incidence of (cardiac death + nonfatal MI) was sig. lower in bisoprolol recipients (2.1% vs. 6.0%) ("DECREASE IV" trial; Ann. Surg. 249:921, 2009-JW)

    8. ACC/AHA guidelines 2009 (Circ. 120:2123, 2009)

      1. Class I if:

        1. Currently on beta-blockers for any class I indication (angina, symptomatic arrhythmias, hypertension, heart failure, etc.)

      2. Class IIa if:

        1. Known CHD or ischemia on preoperative testing and planning vascular surgery.

        2. 2 or more "clinical risk factors":

          1. History of ischemic heart disease

          2. History of heart failure

          3. History of cerebrovascular disease

          4. Diabetes mellitus

          5. Renal insufficiency (preoperative serum Cr of > 2 mg/dL)

  1. "When possible and where indicated, beta blockers should be started several days or weeks before elective surgery.  The dose shoudl be titrated perioeratively to achieve adequate heart rate control...of 60 to 80 BPM...while seeking to minimize the considerable risks of hypotension and bradycardia seen in POISE."

    Alpha-adrenergic agonists (Clonidine and the alpha2-agonist mivazerol )

    1. 2854 patients w/ known CAD or sig. risk factors undergoing noncardiac surgery randomized to IV mivazerol 1.5ug/kg/h vs. placebo x 72 hours postop. Among patients with an established history of CAD undergoing general surgical procedures, the rate of MI was no different, but the cardiac death rate was reduced (13/946 vs. 25/941). Among patients undergoing vascular procedures, both cardiac death rate (6/454 vs. 18/450) and the combined end point of death or MI (44/454 vs. 64/450) were significantly reduced. (Anesthesiology 91:951, 1999; cited in 2002 ACC/AHA guidelines)
    2. The Multicenter Study of Perioperative Ischemia Research Group randomized 300 pts with known CAD undergoing noncardiac surgery to high-dose (1.5 mcg per kg per h) or low-dose (0.75 mcg per kg per h) mivazerol or placebo. No differences in perioperative death or MI were observed, but the high-dose group had significantly less myocardial ischemia than the placebo group (2/98 vs. 6/103) (Anesthesiology 86:346, 1997; cited in 2002 ACC/AHA guidelines)
    3. In a study of 190 high-risk pts (known CAD, h/o vascular surgery, or 2 or more of (age > 60yo, HTN, smoking, dyslipidemia, or DM) scheduled to undergo elective noncardiac surgery, randomized to clonidine (0.2mg PO night before surgery and am of surgery and 0.2mg/d transdermal removed on post-op day #4) vs. placebo, the clonidine group had sig. lower 30-day (1% vs. 6%) and 2-year (15% vs. 29%) mortality rates (Anesthesiology 101:284, 2004--JW)
    4. Class IIb for perioperative control of hypertension, or known CAD or major risk factors for CAD (ibid.)
  1. Ca-Blockers--Only 2 studies "too small to allow definitive conclusions" (2002 ACC/AHA guidelines)
  2. HMG-CoA Reductase Inhibitors ("Statins")
    1. In a study in 497 statin-naive pts scheduled for elective vascular surgery randomized to fluvastatin 80mg/d vs. placebo starting several wks prior to surgery and continued x 1mo postoperatively, 30d incidence of myocardial ischemia was sig. lower in fluvastatin group (11% vs. 19%) as was 30d incidence of (nonfatal MI or cardiovascular-related death) (5% vs. 10%) (NEJM 361:980, 2009-JW)
    2. In a study in 1,066 pts with estimated "intermediate" risk for perioperative adverse events (1%-6%) randomized to fluvastatin 80mg/d vs. no fluvastatin (in a 2 x 2 study design that also included bispropolol vs. no bisoprolol; placebos were not used!) starting 1mo prior to surgery, 30d incidence of (cardiac death or nonfatal MI) was not sig. diff. between fluvastatin recipients vs. nonrecipients ("DECREASE IV" trial; Ann. Surg. 249:921, 2009-JW)

VII. Intraoperative interventions to improve perioperative outcomes

  1. Pulmonary artery catheter
    1. Evidence from controlled trials is scant and a large-scale cohort study demonstrated potential harm, but "the use of pulmonary artery catheters may benefit high-risk patients." (2002 ACC/AHA guidelines)
    2. In a randomized trial of 1,994 "high-risk" patients (American Society of Anesthesiologists class III or IV) > 60yo scheduled to undergo major surgery (abdominal, thoracic, vascular, or hip-fx) randomized to a pulmonary artery catheter (placed preoperatively, target O2-delivery index 550-600mL/min/m2, CI 3.5-4.5 L/min/m2, MAP 70mm Hg, PCQP 18mm Hg, HR < 120, HCT > 27%) vs. "standard care," there were no sig. diffs in in-hospital or 1y mortality; ditto for subgroups that were analyzed; PAC pts were sig. more likely to have PE (NEJM 348:5, 2003--JW)
  2. Computerized  ST-segment monitoring:

    1. Superior to visual interpretation in the identification of ST-segment changes but can get false-positive results.  No studies have measured effect on outcomes.  Considered Class IIa for patients with known CAD or undergoing vascular surgery (ibid.)

  3. IV nitroglycerin:

    1. Only class I for high-risk patients previously taking nitroglycerin who have active signs of myocardial ischemia, without hypotension (ibid.)

  4. Active warming:

    1. Several methods available; the most widely studied is forced-air warming.  One randomized trial showed sig. reduction in CV events with active forced air warming (JAMA 277:1127-34, 1997).  

VIII. Screening for and management of postoperative Myocardial Infarction

  1. See also section on Acute MI

  2. Per 2002 ACC/AHA guidelines:

    1. In patients w/o documented CAD, restrict surveillance to patients who develop signs of CV dysfunction.

    2. In patients with high or intermediate clinical risk (see figures) who have known or suspected CAD and who are undergoing high- or intermediate-risk surgical procedures, consider:

  1. ECGs at baseline, immediately after the surgical procedure, and daily x 2d

  2. Troponin 24 hours postoperatively and on day 4 or hospital discharge (whichever comes first)

  1. Management of postop MI:

    1. Thrombolysis us. contraindicated postop b/c of bleeding risk

    2. Reperfusion procedures-If MI is not due to acute coronary occlusion (e.g. fron postoperative tachycardia or hypertension), tx underlying cause before reperfusion tx

    3. If elevated CK-MB band or cardiac troponin, but otherwise clinically stable, no evidence to support immediate angiography.

Sources include “2002 ACC/AHA guidelines”: Eagle KA, et al., ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery update: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1996 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery). 2002. American College of Cardiology Web site)