Pre-Op Risk Assessment - Pg 1
Testing Strategy
EHJ 2009 Guidelines
(ii) coronary plaque rupture due to vascular inflammatory processes presenting as ACS.

-The Dutch Echocardiographic Cardiac Risk Evaluating Applying Stress Echo (DECREASE) -I, -II and -IV trials -
3893 surgical patients (1996–2008), comprised intermediate- and high-risk patients of whom 136 (
3.5%) suffered
perioperative cardiac death or MI.
-The Perioperative Ischaemic Evaluation (POISE) trial, (2002–2007), 8351 patients undergoing non-cardiac
surgery. Perioperative
mortality occurred in 226 patients (2.7%), of whom 133 (1.6%) suffered cardiovascular
death
, whereas non-fatal MI was observed in another 367 (4.4%) subjects.
Major non-cardiac surgery     = cardiac death                              0.5 - 1.5%
                             = major cardiac complications      2.0 and 3.5%
                  Every operation elicits a stress response.
-Initiated by tissue injury
-Mediated by
neuroendocrine factors
-
Fluid shifts in the perioperative period
-Increased myocardial oxygen demand
-Alterations in the balance between prothrombotic and fibrinolytic factors, resulting in hypercoagulability
and possible coronary thrombosis (elevation of fibrinogen and other coagulation factors, increased
platelet activation and aggregation, and reduced fibrinolysis).
The extent of such changes is proportionate to the extent & duration of the intervention.
-Infra-inguinal revascularization entails a cardiac risk similar to or even higher than aortic procedures. This
can be explained by the higher incidence of diabetes, renal dysfunction, IHD, advanced age in this patient group.

-Laparoscopic procedures have the advantage of causing less tissue trauma and intestinal paralysis resulting
in less incisional pain and diminished postoperative fluid shifts related to bowel paralysis. On the other hand, the
pneumoperitoneum used in these procedures results in elevated intra-abdominal pressure and a reduction in
venous return. It will result in a decrease in cardiac output and an increase in systemic vascular resistance.
Therefore, cardiac risk in patients with heart failure is not diminished.

Functional capacity

1 MET - Basic Metabolic Demand at rest
4 METS - Climbing 2 flightds of stairs                        (<4 METS = RR 18.7 of post-operative mortality)
10 METS - Swimming
Indices:
Goldman (1977), Detsky (1986), and Lee (1999)
Lee Index: (modification of Goldman), developed using prospectively collected data on 2893 patients (validated
in another 1422 pts).
5 factors: IHD - CVA - CHF - IDDM - CKD - High risk surgery (1 point each)
0        0.4%
1        0.9%
2        7%
=>3    11%
However patients undergoing thoracic (12%), vascular (21%, and orthopedic surgery (35%), were overepresented
Also the study was underpowered (only 56 cardiac events). The type of surgery was only classified as 2 subtypes:
1-high-risk, including intraperitoneal, intrathoracic, and suprainguinal vascular procedures
2-all remaining non-laparoscopic procedures, mainly including orthopaedic, abdominal, and other vascular

The prognostic significance of even small elevations in
Troponins has been independently confirmed in   studies
and in clinical trials (
TACTICS-TIMI 18, FRISC II, OPUS-TIMI). The prognosis for all-cause death in patients with
end-stage renal disease and with even minor elevations in cTnT is
2–5 times worse than for those with
undetectable values.

CRP is an acute-phase reactant produced in the liver. CRP is also expressed in smooth muscle cells within
diseased atherosclerotic arteries and has been implicated in many aspects of atherogenesis and plaque
vulnerability, including expression of adhesion molecules, induction of nitric oxide, altered complement function,
and inhibition of intrinsic fibrinolysis. However, in the surgical setting,
no data are currently available using
CRP as a marker for the initiation of risk reduction strategies.

NT-proBNP is produced in cardiac myocytes in response to increases in myocardial wall stress. Markers of CHF
regardless of the pesence orabsence of myocardial ischemia. Pre-operative levels have additional prognostic
value for long-term mortality and for cardiac events after major non-cardiac vascular surgery.

Data on pre-operative biomarker use from prospective controlled trials are sparse. Based on the present data,
routine assessment of serum biomarkers for patients undergoing non-cardiac surgery cannot be
proposed for routine use as an index of cell damage.

ECG: A retrospective study investigated 23 036 patients scheduled for 28 457 surgical procedures; patients with
abnormal ECG findings had a greater incidence of cardiovascular death than those with normal ECG results
(
1.8% vs. 0.3%). In patients who underwent low-risk or low- to intermediate-risk surgery, the absolute difference in
the incidence of cardiovascular death between those with and without ECG abnormalities was only
0.5%.

Echo: an EF of35% had a sensitivity of 50% and a specificity of 91% for prediction of perioperative non-fatal MI
and cardiac death.

Stress Tests:
-Treadmill testing in vascular surgery patients low sensitivity (74%) and specificity (69%)
-
Dipyridamole myocardial perfusion imaging,  in a meta-analysis of vascular surgery patients, 1179
vascular surgery, 7%
Lee Index: (modification of Goldman), developed using prospectively collected data on 2893 patients (validated
in another 1422 pts).
5 factors: IHD - CVA - CHF - IDDM - CKD - High risk surgery (1 point each)
0        0.4%
1        0.9%
2        7%
=>3    11%
However patients undergoing thoracic (12%), vascular (21%, and orthopedic surgery (35%), were overepresented
Also the study was underpowered (only 56 cardiac events). The type of surgery was only classified as 2 subtypes:
1-high-risk, including intraperitoneal, intrathoracic, and suprainguinal vascular procedures
2-all remaining non-laparoscopic procedures, mainly including orthopaedic, abdominal, and other vascular

The prognostic significance of even small elevations in
Troponins has been independently confirmed in   studies
and in clinical trials (
TACTICS-TIMI 18, FRISC II, OPUS-TIMI). The prognosis for all-cause death in patients with
end-stage renal disease and with even minor elevations in cTnT is
2–5 times worse than for those with
undetectable values.

CRP is an acute-phase reactant produced in the liver. CRP is also expressed in smooth muscle cells within
diseased atherosclerotic arteries and has been implicated in many aspects of atherogenesis and plaque
vulnerability, including expression of adhesion molecules, induction of nitric oxide, altered complement function,
and inhibition of intrinsic fibrinolysis. However, in the surgical setting,
no data are currently available using
CRP as a marker for the initiation of risk reduction strategies.

NT-proBNP is produced in cardiac myocytes in response to increases in myocardial wall stress. Markers of CHF
regardless of the pesence orabsence of myocardial ischemia. Pre-operative levels have additional prognostic
value for long-term mortality and for cardiac events after major non-cardiac vascular surgery.

Data on pre-operative biomarker use from prospective controlled trials are sparse. Based on the present data,
routine assessment of serum biomarkers for patients undergoing non-cardiac surgery cannot be
proposed for routine use as an index of cell damage.

ECG: A retrospective study investigated 23 036 patients scheduled for 28 457 surgical procedures; patients with
abnormal ECG findings had a greater incidence of cardiovascular death than those with normal ECG results
(
1.8% vs. 0.3%). In patients who underwent low-risk or low- to intermediate-risk surgery, the absolute difference in
the incidence of cardiovascular death between those with and without ECG abnormalities was only
0.5%.

Echo: an EF of35% had a sensitivity of 50% and a specificity of 91% for prediction of perioperative non-fatal MI
and cardiac death.

Stress Tests:
-Treadmill testing in vascular surgery patients low sensitivity (74%) and specificity (69%)
-
Dipyridamole myocardial perfusion imaging,  in a meta-analysis of vascular surgery patients, 1179
vascular surgery, 7% event rate (death or MI). Reversible ischemia in:
<20%               No change in LR
20-29%            LR 1.6
30-49%            LR 2.9
> 50%              LR 11
-A 2nd meta-analysis reported a sensitivity of 83% and specificity of 47% for MPI
-Dipyridamole thallium-201
imaging in vascular surgery over 9 years (1985–1994). The 30-day cardiac death
or non-fatal MI rates were:
1% in patients with normal test
7% in patients with fixed defects
9% in patients with reversible defects

-Dobutamine Stress Echo:
60% low risk (no ischaemia)                                                 0% post-op event rate
32% intermediate risk (ischaemic threshold 60%)             9% post-op event rate    
8%   high risk (ischaemic threshold ,60%)                           43% post-op event rate
Sensitivity and specificity of DSE for perioperative cardiac death and MI are 85 and 70%
DSE NPV is high (80-90%), PPV  is low (25-45%), meaning that the post-surgical probability of a cardiac event is
low, despite wall motion abnormality detection during stress echocardiography

(See attached article on top for CT, MRI and integrated cardiopulmonary testing recommendations.)
event rate of vascular surgery patients on b-blocker therapy was already so reduced that test results and
subsequent alteration in perioperative management were redundant.
No differences in cardiac death and MI at 30 days were observed between 770 patients assigned to no cardiac
stress testing vs. testing (1.8 vs. 2.3%). Importantly, pre-operative testing delayed surgery for >3 weeks.
- High risk surgery (1 point each)
0        0.4%
1        0.9%
2        7%
=>3    11%
Pre-op 1
Testing
Pre-op 3
Treatment
Pre-op 2
Treatment
Specifics
Canadian 2014 preop guidelines
USA preop 2014 guidelines