TAAA / Spinal Cord Protection

Hazim J. Safi, MD

Department of Cardiothoracic and Vascular Surgery

McGovern Medical School

The University of Texas Science Center at Houston

Memorial Hermann Heart & Vascular Institute

Professor and Chair

International Cardiovascular Surgery Mini-Symposium 2018

January 1984

Uni P = 0.0001 Multi P = 0.007 H.R. 1.6

1993

Extent

Classification

15% 31% 7% 4%

Clamp and Go Era

All Aneurysm Types

Rationale for

Spinal Cord Protection

1. Distal aortic pressure

2. Moderate hypothermia

3. CSF pressure

Spinal Cord Protection

90° to table

60° hip rotation

patient’s back is near edge of table

CSF Drainage

1286 TAAA & DTAA Repairs:

(Jan 1991 – Aug 2006)

Median age: 67 (8-92)

64% 36%

Variable %

Smoking 32

Hypertension 73

Cerebrovascular Disease 11

Coronary Artery Disease 27

Renal Disease 19

Acute Dissection 4

Chronic Dissection 25

Pre-Operative Characteristics

Variable

Intercostal Artery Reattachment 39%

Pump time 44 min

Aortic Cross-Clamp Time 46 min

Adjunct use 74%

Operative Factors

Jan ‘91 –

Jan ‘95

Evolution of TAAA Surgery in Quartiles

Feb ’95 –

May 98 Jun ’98 –

Jul ‘01 Aug ‘01 –

Aug ‘04

Neurologic Deficit n %

Overall 36/1106 3.3

(-) Adjunct 16/283 5.7

(+) Adjunct 20/823 2.4

p=0.008

Results

35 sec/yr

p

p=0.02

All Aneurysm Extents

TAAA II

p=0.0001

Neurologic Deficit Multiple Logistic Regression Analysis

Variable OR p

TAAA Extent II 6.41 0.0001

Renal Dysfunction 2.28 0.03

(+) Adjunct 0.26 0.0004

Aortic Clamp Time 1.01 0.11

Neurologic Deficit X-Clamp and Go Era

No Adjunct

Neurologic Deficit Adjunct Era

Despite increased aortic cross-clamp times, adjunct has reduced overall risk of neurologic deficit

Adjunct use has blunted effect of aortic cross-clamp time

Adjunct may allow surgeon to operate without pressure of time

Conclusions

Median Age: 67 (8 – 85)

Adjunct 246/300* (82%)

64% 36%

*Now 394

Classification

Classification DTAAA

30-day mortality 8.0% (24/310)

(In-hospital mortality) 8.7% (26/310)

Neurological Deficit 2.3% (7/300)

Overall

Results

*Neurologic Deficit

Adjunct Group 1.2% (3/238)

Non-Adjunct 6.4% (4/62)

* p=0.02

Results

Adjunct Group

Immediate 0.8% (2)

Delayed 0.4% (1)

Non-Adjunct

Immediate 4.7% (3)

Delayed 1.6% (1)

Neurologic Deficit

Results

TAAA

AAA

Fistula

Freedom From Reoperation

DAP & CSFD can be performed with acceptable

morbidity and mortality significantly reducing the

incidence of neurological deficits during repair of

DTAA

Open Repair appears durable

Classification - prognostic significance

Results

Delayed Neurological

Complication

+CSFD -CSFD

Immediate 20.1% 21.2%

Delayed 8.3% 11.5%

1990

Extent II 3.12

Results

75%

43% 0%

Delayed

Improved

Cases Controls OR P

Hemoglobin

Results*

OR 95% CI P

MAP

Correctly Classified

N GFR / Ab Cr

N Cr / Ab GFR

1106 TAAA & DTAA Repairs:

(1991 –2004)

Median age: 67 (8-92)

64% 36%

30-Day Mortality

p = 0.0001

Patients

Deaths

27% 18% 10% 5%

30-Day Mortality

Patients

Deaths

Conclusion

Subclinical pre-existing renal disease is

prevalent in TAAA patients

GFR versus serum creatinine

More sensitive index of renal function

Better predictor of mortality

Neuromonitoring

Jan 2000 - Jan 2006

444 SSEP in DTA/TAA repair

Data collected prospectively &

reviewed retrospectively

68 years (20 - 87 years)

158 (36%) 286 (64%)

Methods

Right & left PTN alternatively stimulated at the ankle to get a sustained waveform

SSEP Monitoring

Rate = 4.7 Hz

Stimulus Duration = 0.05 – 0.7 sec

Intensity = 0.3 Amp

Sensory

10%

50%

SSEP Monitoring

Group 1

Normal SSEP

Group 2

Transient Change Group 3

Persistent Change

SSEP changes classified into three groups

Sensitivity for immediate ND: 62.5

Specificity for immediate ND: 81.2

NPV of SSEP for immediate ND: 99.2%

Results

Motor

Overall ND: 8/233 (3.1%)

Permanent SSEP Change: 9/233 (3.8%)

Permanent MEP Change: 11/233 (4.7%)

Sensitivity:

37.5% SSEP

62.5% MEP

Specificity and negative predictive value

>97% for both

‘Any’ Change (Transient and permanent)

Sensitivity

Specificity

False Positive

Conclusion

If there is no change at the end of

operation, > 97% awakening with no ND

MEP have not added any additional

benefit in detecting ND

Thank You