Preoperative Coronary Artery Bypass Surgery Prognosis Score - Equation

Description

The prognosis in patients being evaluated preoperatively for coronary artery bypass surgery can be estimated using a clinical severity score using 13 clinical and laboratory factors.

Preoperative factors evaluated:

(1) age

(2) body weight

(3) emergency need for surgery

(4) history of previous vascular surgery

(5) history of previous heart surgery

(6) history of previous cardiovascular disease

(7) history of chronic obstructive lung disease

(8) history of diabetes mellitus requiring oral drug or insulin therapy

(9) aortic stenosis

(10) mitral insufficiency

(11) severe left ventricular dysfunction

(12) hematocrit

(13) serum creatinine

Preoperative Factor	Finding	Points
serum creatinine	< 1.6	0
	>= 1.6 to <= 1.8 mg/dL	1
	>= 1.9 mg/dL	4
emergency case	yes	6
	no	0
reoperation	yes	3
	no	0
severe left ventricular dysfunction	present	3
	absent	0
operative mitral valve insufficiency	present	3
	absent	0
age	< 65	0
	>= 65 and <= 74	1
	>= 75	2
prior vascular surgery	present	2
	absent	0
chronic obstructive lung disease with use of bronchodilating drugs	present	2
	absent	0
anemia (hematocrit <= 34%)	hematocrit <= 34%	2
	hematocrit > 34%	0
aortic valve stenosis, operated	present	1
	absent	0
body weight <= 65 kilograms	<= 65 kilograms	1
	> 65 kilograms	0
diabetes, on oral agent or insulin therapy	present	1
	absent	0
cerebrovascular disease	present	1
	absent	0

where:

• An emergency case defined as unstable angina, unstable hemodynamics or ischemic valvular dysfunction that could not be controlled medically, complications of percutaneous transluminal angioplasty or complications of cardiac catheterization.

• Reoperation indicates previous surgery on the heart.

• Severe left ventricular dysfunction is associated with an ejection fraction of < 35%.

• Prior vascular surgery includes carotid endarterectomy or heart valve replacement.

• "Aortic valve stenosis, operated" is not described further. I will take it has being a history of surgery for aortic stenosis.

clinical severity score =

= SUM(points for 13 preoperative factors)

Interpretation:

• minimum score: 0

• maximum score: 31

Severity Score	Morbidity	Mortality
0	3%	< 1%
1	4%	1%
2	6%	2%
3	10%	2%
4	12%	2%
5	11%	3%
6	18%	4%
7 - 9	23%	7%
>= 10	50%	27%

estimated from Figures 1 and 2 pages 2346-2347

Morbidity included one or more of the following:

(1) cardiac complications

(2) need for mechanical ventilation

(3) central nervous system complication

(4) oliguric or anuric renal failure

(5) serious infection

(6) death

Mortality included:

(1) death during hospitalization for surgery, regardless of length of stay

(2) death within 30 days of hospital discharge

Logistic Regression Analysis

The authors developed the clinical severity score from logistic regression analysis for morbidity and mortality associated preoperative factors.

Factor	Coefficient for Morbidity	Coefficient for Mortality
emergency case	2.198	2.020
serum creatinine >= 1.9 mg/dL	1.043	1.306
reoperation	0.894	1.066
severe left ventricular dysfunction	0.727	1.334
mitral valve insufficiency	0.953	0.929
age per decade	0.374	0.662
diabetes on medication	0.388
weight <= 65 kilograms	0.374
anemia with hematocrit < 34%	0.449	0.987
COPD on medication	0.387	0.872
cerebrovascular disease	0.339
aortic stenosis, operated	0.401
prior vascular surgery	0.340	0.918
constant	-5.073	-9.216

from Table 2 page 2346

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Description

Specialty

Objective

ICD-10

Preoperative Clinical Severity Score of Higgins et al in Coronary Artery Bypass Patients

Purpose: To use a clinical severity score based on preoperative factors to evaluate a candidate for coronary artery bypass surgery.

Description

Specialty

Objective

ICD-10