1. Pre-operative Assessment
Rami Baddredine, MD (Anticoagulation)
Miriam Jacob, MD (Anticoagulation and diabetes)
Karen Joynt, MD (Pulmonary)
James Yau, MD (Cardiovascular)
Edited by Amy Shaheen, MD

2. At the completion of this presentation, the learner should be able to:
Learning Objectives
At the completion of this presentation, the learner should be able to:
Describe appropriate pre-operative cardiovascular evaluation
Describe appropriate pre-operative pulmonary evaluation
Manage anticoagulation in the peri-operative period
Manage diabetes in the peri-operative period
Locate resources related to the above topics on the internet

3. Cardiovascular evaluation Pulmonary evaluation
Presentation Outline
Cardiovascular evaluation
Pulmonary evaluation
Management of anticoagulation
Management of diabetes
Online resources
Quiz
References

4. Cardiovascular Pre-op evaluation

5. Cardiac Preoperative Evaluation
Epidemiology
The prevalence of cardiovascular disease increases with age.
Estimated that the number of people >65 in the US will increase by 25-35% over next 30 years.
This is the same population in which the most surgical procedures are performed.
Number of noncardiac surgeries may increase from 6 million per year to 12 million per year; some of which have been associated with significant periop cardiac morbidity and mortality.

6. Cardiac Preoperative Evaluation
ACC/AHA Guideline on Perioperative Cardiovascular Evaluation for Noncardiac Surgery
First developed by ACC/AHA Task Force on Practice Guidelines in 1996.
Updated in 2002.
Provides framework for considering cardiac risk in noncardiac surgeries.
Provides tables and algorithms for quick reference and decision making.

7. Cardiac Preoperative Evaluation
Purpose
Not to give “medical clearance”.
Perform an evaluation of the patient’s current medical status.
Make recommendations concerning the evaluation, management, and risk of cardiac problems over the entire perioperative period
No test should be performed unless it will influence patient treatment.
Must be carefully tailored to the patient and the circumstance.

8. Cardiac Preoperative Evaluation
Need for noncardiac surgery
Urgent or elective
emergency
Coronary revascularization
Within 5 years?
YES
Operate
(OK for surgery)
Recurrence of symptoms NO NO
Recent coronary evaluation
Within 2 years?
YES
Recent stress test or
Coronary angiogram
favorable results
YES NO
CLINCAL PREDICTORS
(see next set of algorithms)
Unfavorable results

9. Cardiac Preoperative Evaluation
Next step is to evaluate the patient’s risk and the inherent riskiness of the surgery
Patient’s risk is determined by clinical predictors and functional capacity
Surgery riskiness is determined by the type and site of surgery
Once patient’s risk and surgery’s risk are known, additional algorithms can be used to determine the appropriate course of action

10. Cardiac Preoperative Evaluation: Clinical predictors
Clinical Predictors of Increased Perioperative Cardiovascular Risk
Major
Intermediate
Low
Unstable coronary synd٭
Mild angina
Advanced age
Decompensated CHF
Prior MI (hx or ECG)
Abnormal ECG †
Significant arrhythmias#
Compensated or prior CHF
Rhythm other than sinus
Significant valvular dz
Diabetes mellitus
Low functional capacity
Renal insufficiency
History of stroke
Uncontrolled HTN
٭acute (within 7 days) or recent (7-30 days) MI or class III or IV symptoms
#high grade AV block, symptomatic ventricular arrhythmia with underlying heart disease, or SVT with uncontrolled ventricular rate
†LVH, LBBB, ST-T abnormalities

11. Cardiac Preoperative Evaluation: Functional capacity
Functional capacity is also an important part of the algorithm and relies on “METs”, or metabolic equivalents, to rate a patient’s functionality
1 MET is equivalent to a metabolic rate consuming 3.5 milliliters of oxygen per kg of body weight per minute or 1 kilocalorie per kg of body weight per hour
In a treadmill test, actually measuring METs requires that the person being tested wear a mask in order to measure his or her oxygen consumption (and the carbon dioxide exhaled)
However, METs can be estimated as follows:
1-4 METs: daily activities, walking 1-2 blocks on level ground at 2-3 mph, light housework
4-10 METs: climbing stairs or hill, jogging short distance, heavy housework, bowling, dancing, golf, swimming
10-14 METs: running (at least an 8-minute mile), downhill skiing, rock climbing, etc.

12. Cardiac Preoperative Evaluation: surgical riskiness
Cardiac Risk* Stratification for Non-cardiac Surgical Procedures
High (>5%)
Intermediate (<5%)
Low (<1%)
Emergent major operations,
especially in the elderly
Carotid endarterectomy
Endoscopic procedures
Major vascular or peripheral vascular surgery
Head and neck operations
Superficial procedures
Prolonged surgery with large fluid shifts or blood loss
Intraperitoneal and intrathoracic operations
Cataract surgery
Orthopedic procedures
Breast surgery
Prostate surgery
٭combined risk of cardiac death and nonfatal myocardial infarction

13. Cardiac Preoperative Evaluation
Patient with
MAJOR CLINICAL
PREDICTORS
Consider delaying or canceling
non-cardiac surgery
Consider coronary angiography
Medical management and
risk factor modification
Subsequent care* dictated by
findings and treatment results
*subsequent care may include delay or canceling surgery, coronary revascularization followed by non-cardiac surgery, or intensified care.

14. Cardiac Preoperative Evaluation
Patient with INTERMEDIATE
CLINICAL PREDICTORS
Poor functional capacity
(<4 METS)
Mod or excellent
(>4 METS)
high
surgical risk
Intermediate
surgical risk
low
surgical risk
Low risk
Operate
Noninvasive testing
High risk
Consider coronary
angiography
Subsequent care dictated by
findings and treatment results

15. Cardiac Preoperative Evaluation
Patient with NO OR MINOR
CLINICAL PREDICTORS
Poor functional capacity
(<4 METS)
Mod or excellent
(>4 METS)
high
surgical risk
Intermediate or
low surgical risk
Low risk
Operate
Noninvasive testing
High risk
Consider coronary
angiography
Subsequent care dictated by
findings and treatment results

16. Pulmonary Pre-op evaluation

17. Existing literature focuses on:
Pulmonary evaluation
Currently no published guidelines are available for the general surgical patient
Existing literature focuses on:
Evaluation of the lung cancer patient prior to lung resection
Evaluation of risk for post-operative pneumonia
General guidelines are reportedly forthcoming this year

18. Evaluation of the lung cancer patient prior to lung resection
30,000 lung resections are performed annually
Mortality rate from lung resection surgery is 7-11%
Accurate pulmonary evaluation can predict risk of operative mortality and help stratify patients in terms of treatment options (Beckles 2003, Datta 2003)

19. Preoperative evaluation
Staged, stepwise assessment to evaluate risk of complications (Beckles 2003, Datta 2003), starting with careful history and physical examination and then proceeding to objective testing
Stage I assessment
Spirometry / DLCO measurement, +/- ABG
If FEV1>80% predicted or >2L, MVV is >55% predicted, and DLCO is >60% predicted, pt is suitable for resection including pneumonectomy without further evaluation
If pt does not meet these criteria, proceed to stage II testing
Stage II assessment
Quantitative V/Q scan or differential lung scan
If predicted postoperative (ppo) FEV1 is >40% predicted and ppo DLCO is >40% predicted, pt is suitable for resection including pneumonectomy
If pt does not meet these criteria, proceed to stage III testing

20. Preoperative evaluation continued
Stage III assessment
Exercise testing
If VO2 max is greater than 20 mL/kg/min, pt is suitable for surgery
If VO2 max is less than 10 mL/kg/min (roughly the ability to walk up one flight of stairs), pt is at greatly increased risk of complications and death from surgery and non-surgical management should be pursued
Alternative algorithm (Wyser 1999)
If FEV1 or DLCO <80% predicted, proceed directly to exercise testing
If VO2 max >20, proceed to surgery
If VO2 max 10-20, undergo quantitative V/Q and calculate ppo values as before

21. Evaluation of risk for post-operative pneumonia
Why is post-op PNA important?
Pneumonia is the 3rd most common postop complication (after UTI, wound infection) (Garibaldi 1981)
Pneumonia occurs in 10-40% of patients in the post-op period and carries a mortality of 30-46% (Brooks-Brunn 1997)
25% of deaths occurring within 6 days of surgery are pulmonary in etiology (Brooks-Brunn 1995)

22. Risk Assessment for Post-op PNA
Risk index developed in a sample of 10 VA hospitals using data from the Department of Veterans Affairs National Surgical Quality Improvement Program (NSQIP)
160,805 patients in derivation cohort,
155,266 patients in validation cohort,
2,466 patients developed pneumonia (1.5%), compared with myocardial infarction in only 0.4%
Patients with post-op PNA had a 30-day mortality of 21%, compared with only 2% of the remaining patients

23. PNA Predictors
Most important predictors (Odds Ratios, OR, listed for those predictors with OR for development of PNA of greater than 1.5):
Type of surgery
AAA, OR=4.29
Thoracic surgery, OR=3.92
Upper abdominal surgery, OR=2.68
Neck surgery, OR=2.30
Neurosurgery, OR=2.14

24. PNA Predictors, continued
Age
>80, OR=5.63
70-79, OR=3.58
60-69, OR=2.38
Functional status prior to surgery
Totally dependent, OR=2.83
Partially depentent, OR=1.83
Weight loss > 10% in last 6 months, OR=1.92
History of COPD, OR=1.72
General anesthesia, OR=1.56
“Impaired sensorium,” OR=1.51

25. Development of Risk Index
Predictors were then turned into a scoring system, based on strength of association, to allow prospective grading of post-operative risk
Scoring system (“risk index”) was then validated on an independent cohort
Notable study limitations: veteran population, very few women, many comorbidities, no data about PFTs was included, no correction for prophylactic antibiotics was possible

26. Postoperative PNA Risk Index
Preoperative Risk Factor
Point value
Type of surgery
AAA repair 15
Thoracic surgery 14
Upper abdominal surgery 10
Neck surgery 8
Neurosurgery
Vascular surgery 3
Age
≥80 years 17
70-79 years 13
60-69 years 9
50-59 years 4
Functional status
Totally dependent
Partially dependent 6
Preoperative Risk Factor
Point value
Weight loss >10% in past 6 months 7
History of COPD 5
Receipt of general anesthesia 4
Impaired sensorium
History of CVA
Blood urea nitrogen level
<8 mg/dL
22-30 mg/dL 2
≥30 mg/dL 3
Transfusion of > 4 units of blood
Emergency surgery
Steroid use for chronic condition
Current smoker within one year
Alcohol intake > 2 drinks/d in past 2 wks
From Arozullah et al 2001

27. Risk Index and Outcomes
Risk Class 1
(0-15 pts) 2
(16-25 pts) 3
(26-40 pts) 4
(41-55 pts) 5
(>55 pts)
Rate of postop PNA in development cohort, %
0.24
1.19
4.0
9.4
15.8
Rate of postop PNA in validation cohort, %
1.18
4.6
10.8
15.9

28. Pre-op evaluation of coagulation and Peri-op management of anticoagulation

29. Management of bleeding risk
Management of bleeding risk in the peri-op period requires consideration of risk of bleeding
Defining the level of hemostatic risk for the proposed surgery is essential
Low Risk surgery:
-nonvital organs are involved
-surgical site is exposed
-limited degree of surgical dissection
-local hemostatic measures are likely to be effective
-the site does not have local fibrinolysis

30. Risk assessment, continued
Moderate / High risk surgeries
Vital organs are involved, with deep or extensive dissection
The site is associated with local fibrinolysis (eg, prostatic surgery, tonsillectomy, oral or nasal surgery)
Local hemostatic measures are ineffective (eg, closed liver or kidney biopsy)
The surgical procedure or the underlying condition is expected to induce a hemostatic defect (eg, cardiopulmonary bypass, brain injury, extensive malignancy)
Bleeding complications are frequent and/or are likely to compromise the surgical result

31. Pre-op workup
For low risk surgeries : if the history and physical exam do not suggest bleeding then no more tests are needed
For high risk surgeries : Hx , Physical , platelet count, PT and PTT must be done
If Hx/ PE or Coags suggest high risk bleeding then more sophisticated tests should be obtained ( heme consult would not hurt)
A “ Bleeding Time “ is NOT warranted pre-op because it does not predict severity of bleeding

32. Patients already on anticoagulation
Patients might be on prophylactic or treatment anticoagulation preoperatively
Factors to consider when evaluating risk of bleeding with surgery: Age, comorbidities, type of surgery, anticoagulant regimen/ duration and degree of monitoring

33. Venous Thromboembolism ( VTE)
Temporal relation of VTE to surgery is key
Within the first month after DVT patients must receive both pre and post-op anticoagulation
Between 2-3 months, pre-op anticoagulation is only needed for high risk patients but post-op anticoagulation is recommended to all patients
After 3 months, the risk of bleeding is more than the benefit of anticoagulation so only prophylactic pre and post-op anticoag. is recommended

34. Arterial Thromboembolism (ATE)
The risk of bleeding is similar pre and post-op in patients with ATE
Continue anticoagulation preop for all patients
Continue post-op anticoagulation only if the surgery is minor
High risk ATE patients (Like anticoagulation for prosthetic valves): a heparin bridge is recommended and restart anticoagulation ASAP post-op

35. General Recommendations
Always weigh the risk of thrombosis against risk of bleeding
Patients on oral AC , allow INR to reach 2 pre-op unless high risk bleeding ( INR< 1.5)
Bridge with Heparin if high risk re-thrombosis

36. Peri-op management of diabetes

37. Diabetes- Preoperative Management
Why do we care?
Increased risk of pre-operative infection
Increased post-operative cardiovascular morbidity and mortality
Focus is on cardiopulmonary risk assessment and management
History
Laboratory Studies

38. Diabetes- Preoperative Management
History
Long term complications of DM (i.e. retinopathy, nephropathy, neuropathy, CHD, PVD)
Baseline glycemic control (freq of monitoring, average BS)
Hypoglycemia (frequency, severity, awareness, timing)
Therapy (pharmacologic and non-pharmacologic)
Surgery
Major vs. Minor surgery
When to stop eating
Duration of procedure
Type of Anesthetic – epidural vs. general

39. Diabetes- Preoperative Management
Laboratory Studies
Baseline EKG, renal function
Baseline glucose levels
Use this to assess risk for postoperative wound infections
In case-control study of post-CABG patients, multivariable analysis found patient with preoperative glucose >200 mg/dL had OR of 10.2 for deep sternal wound infections (independent risk factor)2.

40. Diabetes- Preoperative Management
Baseline HbA1c – Not recommended
Study of cardiothoracic surgeries – pt with sternal wound infection had mean HbA1c of 8.44 vs in those without infection but was not statistically significant (p=0.09)3
Non-invasive cardiac testing dependent on risk stratification
Preoperative Glycemic Control – Goals
Avoid hyperglycemia and hypoglycemia
No consensus about how “tight” the control must be (there is data in ICU and post-MI patients not in surgery patients- unsure if this translates)

41. Diabetes- Preoperative Management
Type 2 – Diet modification only
Check BG preoperatively and after
Type 2 – Oral agents
Discontinue agent on morning of surgery
Supplemental sliding scale insulin
Type 1 or 2 – Insulin Therapy
For short procedures, continue SQ regimen
1-2 day before, may switch from long-acting to intermediate acting insulin
May reduce night time intermediate insulin if pt has borderline hypoglycemia

42. Diabetes- Preoperative Management
If in AM and lunch will be eaten- convert as follows
Once daily intermediate in AM  2/3 dose
Twice daily  ½ total dose as intermediate
If pt misses lunch as well – less AM insulin
Once daily  ½ total dose as intermediate
Twice daily  1/3 total dose as intermediate
Multiple short and intermediate  1/3 total dose as intermediate
Multiple short acting  1/3 pre-meal short-acting
Continuous insulin  continue basal infusion, use SSI prn
Later in the day – less AM insulin and start dextrose containing IVF
Long, complex surgeries – use IV Insulin (less variability in BG than with SQ regimen), start early in AM, closely monitor electrolytes.
No optimal regimen has been found, based on experience and expert opinion.
No particular regimen has been found to affect morbidity, mortality, or length of stay.

43. Online resources for further info
Cardiovascular evaluation
Pulmonary evaluation
Management of diabetes

44. Quiz
Question One:
Question: A 76 year-old man with history of CAD s/p CABG (3 years ago), HTN, DM2, CVA, CRI, and newly diagnosed lung mass was sent to the cardiology clinic by the surgeon for “cardiac clearance” for resection of the mass. Patient reports that he had been doing well and in his USOH, and the mass was discovered on a recent CXR. What is the most appropriate recommendation for this pt?
A) Pt will need at least a noninvasive test prior to the surgery
B) Pt may proceed with the surgery without further cardiac evaluation
C) Pt will need a coronary angiogram prior to the surgery
D) The surgery should be delayed until he is on optimal medical regimen
Answer: B. Pt may proceed with the surgery without further cardiac evaluation. Pt had recent revascularization procedure (within 5 years – CABG 3 years ago), and has not had recurrence of symptoms. Therefore, he can proceed to noncardiac surgery without any further cardiac evaluation. Pt still need to continue medical therapy and postoperative risk stratification and risk factor modification.

45. Quiz continued Question Two:
Question: As the cardiology consult resident, you are seeing a 72 year-old woman with history of DM2, COPD, and on-going tobacco abuse who was admitted with a fractured pelvis after a fall at home. The patient is a resident at an ALF and fell when she tripped over some furniture. She reports that she has had some difficulty with worsening fatigue and DOE, and she can barely walk across the room because of her symptoms. What is the most appropriate recommendation for this pt awaiting an orthopedic procedure?
A) Pt will need at least a noninvasive test prior to the surgery
B) Pt may proceed with the surgery without further cardiac evaluation
C) Pt will need a coronary angiogram prior to the surgery
D) The surgery should be delayed until she is on optimal medical regimen and has stopped smoking
Answer: A. Pt should have at least a noninvasive cardiac evaluation given that she has at least one intermediate clinical predictor (DM) and poor functional capacity (METS<4). If low risk on the noninvasive test, then she may proceed to the OR; but if high risk, she may need more invasive testing such as coronary angiography.

46. Quiz continued Question Three:
You are asked to evaluate Mr. L, a 65 year old male with known COPD, in pre-op clinic preceding planned resection for a 2 cm right upper lobe nodule. Which of the following statements is FALSE:
A) If Mr. L’s FEV1 is 40% predicted, he should undergo quantitative V/Q scanning and possibly exercise testing prior to surgery
B) If Mr. L’s FEV1 is 50% predicted, he can proceed to surgery without further testing so long as lobectomy is not planned
C) If Mr. L’s FEV1 is 90% predicted with a normal DLCO and MVV, he can proceed to surgery including lobectomy without further testing
D) If Mr. L’s FEV1 is 2.2L, but his DLCO is only 40% predicted, he should undergo further testing prior to surgery
Answer: B – If Mr. L has an FEV1 of 50% predicted, he shouldn’t go directly to surgery – instead, he should undergo quantitative V/Q testing and possibly exercise testing prior to surgery for further risk stratification

47. Quiz continued Question Four:
Question: Which of the following is NOT a significant risk factor for the development of postoperative pneumonia, based on the VA study outlined above?
A) Thoracic surgery
B) Age greater than 70
C) History of inhaler use
D) Receipt of general anesthesia
Answer: C – there is no evidence that a history of inhaler use is directly related to risk for post-op PNA, although COPD has been shown to be a risk factor in various smaller studies.

48. Question Five: Quiz continued
Question: Mr Green is a 69 yo healthy male scheduled to have CABG in 2 weeks. You are asked to asses his bleeding risk. How would you asses him?
A) History alone
B) History and physical exam
C) PT/PTT/platelets
D) All of the above
Answer: D. CABG is a high-risk surgery, so he will need a thorough evaluation prior to the procedure.

49. Question Six: Quiz continued
Question: Mr. Smith is a 68 year old male on Coumadin for a prosthetic mitral valve. He is scheduled to have an inguinal hernia repair. How would you manage his coumadin pre/post-op?
A) Stop Coumadin 3 days pre-op, no need for bridge. Restart Coumadin 3 days post-op
B) Stop Coumadin 3 days preop, bridge with heparin when INR<2.5, restart heparin ASAP post-op, and then restart Coumadin
C) Continue Coumadin through surgery
D) Stop Coumadin one day prior to surgery and do not resume until 1-2 weeks post-op
Answer: B. This patient is at high risk for ATE despite the low-risk nature of the surgery and needs a heparin bridge for his procedure.

50. Question Seven:
Question: Ms. Apple is a 28 year old female undergoing thyroidectomy in one week. Pre-op labs show a PTT of 68, INR of 1.1, and a normal CBC. She give no history of abnormal bruising or bleeding. Your next step is:
A) Proceed with surgery
B) Consult hematology for further workup
C) Proceed with surgery after 4 units FFP
D) Proceed with surgery after 5 mg of Vitamin K SQ x1
Answer: B. This patient has a high-risk surgery (head and neck) and therefore needs further workup (i.e. mixing study, etc.).

51. Question Eight:
Question: What aspect of history, physical or laboratory studies is associated with increased risk of post-operative wound infections?
A) Baseline hemoglobin A1c
B) History of retinopathy
C) Preoperative glucose level
D) Use of insulin
Answer: Preoperative blood glucose > 200 has been associated with increased risk of deep sternal wound infections in post-CABG patients (found to have OR of 10.2).

52. References Cardiovascular evaluation: Pulmonary evaluation:
ACC/AHA Guideline on Perioperative Cardiovascular Evaluation for Noncardiac Surgery,
Pulmonary evaluation:
Arozullah AM, Khuri SF, Henderson WG et al. Development and validation of a multifactorial risk index for predicting postoperative pneumonia after major noncardiac surgery. Ann Intern Med 2001;135:
Beckles MA, Spiro SG, Colice GL et al. The physiologic evaluation of patients with lung cancer being considered for lung resectional surgery. Chest 2003;123:105S-114S
Brooks-Brunn JA. Predictors of postoperative pulmonary complications following abdominal surgery. Chest 1997;111:564-71
Brooks-Brunn JA. Postoperative atelectasis and pneumonia. Heart Lung 1995;24:94-115
Datta D, Lahiri B. Preoperative evaluation of patients undergoing lung resection surgery. Chest 2003;123:
Garibaldi RA, Britt MR, Coleman ML et al. Risk factors for postoperative pneumonia. Am J Med 1981;70:677-80
Wyser C, Stulz P, Soler M et al. Prospective evaluation of an algorithm for the functional assessment of lung resection candidates. Am J Respir Crit Care Med 1999;159:1450-6

53. References Anticoagulation: Diabetes:
The clinical impact of increased sensitivity PT and APTT coagulation assays. Am J Clin Pathol 1999; 112:225.
Williams' Hematology. Beutler, E, Lichtman, MA, Coller, BS, et al (eds). McGraw-Hill, New York, 6th edition, 2001; p. 1471
Outcomes of patients with no laboratory assessment before anesthesia and a surgical procedure. Mayo Clin Proc 1997; 72:505
Usefulness of preoperative laboratory assessment of patients undergoing elective herniorrhaphy. Arch Surg 1992; 127:801
Management of anticoagulation before and after elective surgery. N Engl J Med 1997; 336:1506
Diabetes:
1. Khan NA, Ghali WA. Perioperative management of diabetes mellitus. In: UpToDate, Rose, BD (Ed), UpToDate, Waltham, MA, 2005.
2. Trick WE, et al. Modifiable risk factors associated with deep sternal site infection after coronary artery bypass grafting. J Thorac Cardiovasc Surg 2000 Jan;119(1):
3. Latham R, et al. The association of diabetes and glucose control with surgical-site infections among cardiothoracic surgery patients. Infect Control Hosp Epidemiol 2001 Oct;22(10):