Table 1 Summary of results from studies evaluating IODUS in CEA

Studies comparing (a) completion imaging vs no imaging or (b) different completion imaging modalities

Knappich C

2017

Retrospective analysis of registry data; German statutory nationwide quality assurance database

142,074

Selective; Imaging in 66.9% (95 044/142 074) of cases. Mix of DUS/angiogram/flowmetry or other unspecified modalities. Differential count for imaging modalities not presented in data

Criteria for revision:

Surgeons discretion

Not known

Combined stroke/mortality rate

Scan: 1.7% (1654/95,044), RR 0.86 (CI 0.80–0.93)

No scan: 2% (957/47,030)

Adjusted risk of any stroke or mortality

Intraoperative completion study

Angiogram: RR 0.8 (CI 0.71–0.9) p < 0.001

DUS: RR 0.74 (CI 0.63–0.88) p = 0.001

Flowmetry: RR 0.87 (CI 0.74–1.04) p = 0.121

Other: RR 0.97 (CI 0.80–1.17) p = 0.756

Not known

Wallaert JB

2011

Retrospective analysis of registry data; Vascular Study Group of New England (VSGNE) Registry

6115

Selective; Completion imaging only performed in 2033 cases. DUS in 94% (1919/2033) of cases

Amongst 73 surgeons; completion imaging used rarely (51%), selectively (22%) or routinely (27%)

Criteria for revision:

Surgeon’s discretion

Practice pattern defined as routine (imaging used in ≥ 90% of cases), selective (5% to 90%) and rare (< 5%)

Routine: 7.6%

Selective: 0.8%,

Rare: 0.9%

Combined stroke/mortality rates

Routine: 2.4% (42/1763)

Selective: 1.2% (12/1018)

Rare: 1.7% (55/3334)

Routine v selective v rare; p = 0.048

Risk adjusted; Selective (OR, 0.75; 95% CI 0.40–1.41; p = .366), routine OR, 1.42; 95% CI .93–2.17; p = .106

Revised cases: 3.9% (7/178)

Not revised cases: 1.7% (102/5937)

Revised v not revised; p = 0.028

Risk adjusted; OR 2.1; 95% CI, 0.9–5.0; p = .076

Completion imaging: 2.6%

No completion imaging: 1.3%

Completion imaging v no completion imaging; p < 0.001

Risk adjusted; OR, 1.9; 95% CI, 1.2–2.7; P = .002

Restenosis (> 70%) at 1 year

Routine: 1.1%

Selective: 1.1%

Rare: 2.8%

Routine v selective v rare; p = 0.09

Rockman CB et al

2007

Retrospective analysis of data from the New York Carotid Artery Surgery (NYCAS) study

9278

Selective; Imaging in 35.8% (3318/9278)

Angiogram 5.4% (178/3318), continuous wave Doppler 70.3% (2331/3318), DUS 17.6% (585/3318), combination of angio ± Doppler or DUS 5.9% (196/3318)

Criteria for revision:

Surgeons discretion

Not known

Combined stroke/mortality rate

No scan: 3.8%

Any scan: 4.3%

Angiogram: 5.2%

Doppler: 4.3%

DUS: 4.3%

No statistical significance when comparing ‘no scan’ with ‘any scan’ or when comparing individual modalities with ‘no scan’

Not known

Kinney EV

1993

Prospective single center study

461

Selective; DUS in 410 cases

Criteria for revision:

Severe flow disturbance (PSV > 150 cm/s and spectral broadening) or occlusion in the CCA/ICA/ECA

6.3% (26/410)

Stroke rate

Combined: 2.2% (10/461)

No scan: 0% (0/51)

*Normal scan: 2.1% (7/337)

*Abnormal scan: 4.1% (3/73)

Revisions: 3.8% (1/26)

(*at completion)

Mortality rate

Combined:

2.6% (12/461)

No scan: 0% (0/51)

*Normal scan: 3.3% (11/337)

* Abnormal scan: 1.4% (1/73)

Flow abnormality at 3 months (> 50% category):

Combined: 2.4% (11/461)

No scan: 9.8% (5/51)

*No flow abnormality: 0.3% (1/337)

*Residual flow disturbance: 6.8% (5/73)

Lingenfelter KA

1995

Prospective single center study

53

Routine; combination of hand-held Doppler, DUS and angiogram in all cases

Criteria for revision:

Surgeon’s discretion

11.3% (6/53)

Stroke rate

Combined: 1.8% (1/53)

DUS detected all 6 defects requiring revision. Audible Doppler assessment detected only 1 and DSA 4

Mortality rate

Combined: 0% (0/53)

Not known

Lipski DA

1996

Retrospective study

86

Selective (at surgeons discretion); DUS in 39 procedures

Criteria for revision:

Surgeon’s discretion

23.1% (9/39)

Stroke rate

Combined: 3.5% (3/86)

Scan: 2.6% (1/39)

No scan: 4.3% (2/47)

Mortality rate

Combined: 0% (0/86)

Residual stenosis (> 50%):

Combined: 8.1% (7/86)

Scan: 0% (0/39)

No scan: 14.9% (7/47)

Restenosis (< 50%) at mean follow up of 20 months

Combined: 4.7% (4/86)

Scan: 5.1% (2/39)

No scan: 4.3% (2/47)

Note: significant variation in patch vs primary closure

Lane RJ

1987

Prospective single center study

380

Selective; DUS in 175 cases

Criteria for revision:

Unspecified criteria for 30% stenosis

6.9% (12/175)

Stroke rate

Combined: 2.1% (8/380)

No scan: 2.4% (5/205)

Normal scan: 2.2% (3/136)

Abnormal scan: 0% (0/39)

Mortality rate

Combined: 0.5% (2/380)

No scan: 0.4% (1/205)

Normal scan: 0.7% (1/136)

Abnormal scan: 0% (0/39)

Restenosis at mean follow up of 22 months

Combined: not available

No scan: not available

Abnormal scan: 6.3% (1/16)

Restenosis at mean follow up of 16 months

Normal scan: 9.2% (8/87)

*Only 103 patients followed up

Descriptive studies

Dorffner R

1997

Prospective single center study

50

Routine; DUS in all cases

Criteria for revision:

Surgeons’ discretion

18% (9/50)

Stroke rate

Combined: 4% (2/50)

*Normal scan: 0% (0/32)

Abnormal scan but not revised: 20% (2/10)

Revised: 0% (0/9)

*Normal at completion

Mortality rate

Combined: 0% (0/50)

Restenosis at mean follow up of 10 months

Normal scan: 6.3% (2/32)

Abnormal scan but not revised: 20% (2/10)

Revised: 0% (0/9)

Mays BW

2000

Prospective single center study

100

Routine; DUS in all cases

Criteria for revision:

PSV > 150 cm/s and spectral broadening indicating severe flow disturbance in CCA, ICA or ECA. If no obvious cause for flow disturbance was identified then angiogram was performed prior to revision. In addition, flaps in distal ICA and defects > 2 mm in the CCA or bulb were revised in the presence of a PSV > 125 cm/s colour mosaic or loss of spectral window

21% (21/100)

Stroke rate

Combined: 1% (1/100)

Mortality rate

Combined: 1% (1/100)

At 6 weeks:

Revisions: 1/21 showed an occluded ICA and 2/21 showed residual stenosis

No abnormality on completion: 10/79 showed recurrent stenosis (16% to 49% category)

Yuan

2014

Prospective single surgeon series

285

Routine; DUS in all cases

Criteria for revision:

Visible ICA kinking with PSV ≥ 120 cm/s

3.9% (11/285)

Stroke rate

Combined: 1.1% (3/285)

Repaired ICA kinking: 0% (0/11)

Unrepaired ICA kinking: 0% (0/16)

Mortality rate

Combined: 0% (0/285)

Repaired ICA kinking: 0% (0/11)

Unrepaired ICA kinking: 0% (0/16)

By 9–24 months:

Combined: 1.8% (5/284)

Repaired ICA kinking: 9.1% (1/11) restenosis (60–79%), 9.1% (1/11) occlusion

Unrepaired ICA kinking: 0% (3/15*) mild 0–40% stenosis

(*one patient lost to f/u)

Baker

1994

Retrospective single center study

316

Selective; DUS in 283 cases

Criteria for revision:

Surgeon’s discretion

2.8% (9/316)

Stroke rate

Combined: 1.6% (5/316)

Normal scan: 1.6% (4/254)

Unrepaired minor defects: 1.9% (1/53)

Revised defects: 0% (0/9)

Mortality rate

Combined: 0.3% (1/283)

(Single death was in the normal scan group)

*316 cases in 283 patients

Stenosis (> 75%) at mean follow up of 21.6 months:

Combined: 5.7% (18/316)

Normal scan: 3.2% (8/251*)

Unrepaired minor defects: 17.3% (9/52*). One of these arteries later occluded

Revised defects: 11.1% (1/9)

Note: restenosis was correlated with primary and patch closure (p = 0.025)

*No of patent vessels in surviving patients

Panneton JM

2001

Retrospective single center study

155

Routine; DUS in all cases

Criteria for revision:

PSV > 125 cm/s and marked plaque/thrombus or large intimal flap/dissection in the CCA, IC or ECA

9% (14/155)

Stroke rate

Combined: 1.9% (3/155)

Normal scan: 1.1% (1/91)

Minor defects: 0% (0/47)

Revised major defects: 0% (0/14)

Unrevised major defects: 66.7% (2/3)

Mortality rate

Combined: 0.7% (1/149*)

(1 death in patient with unrevised major defect)

*155 cases in 149 patients

Restenosis at 6 months*:

Normal scan: 1.1% (1/91) restenosis

Minor defects: 2.1% (1/47)

Revised major defects: 0% (0/14)

*(Asymptomatic > 50%)

Steinmetz OK

1998

Retrospective single surgeon series

100

Routine; DUS in all cases

Criteria for revision:

Intraluminal thrombosis or focal elevation of PSV > 120 cm/s and marked spectral broadening in either CCA, ICA or ECA

2% (2/100)

Stroke rate

Combined: 2% (2/100)

Mortality rate

Combined: 1% (1/100)

Abnormality at mean follow up of 9.2 months

Combined: 13.6% (12/88)

(< 50% stenosis in 6, > 50% stenosis in 5, asymptomatic occlusion in 1)

*Follow up scans available in 88 patients

Ascher E

2004

Prospective single center study

650

Routine; DUS in all cases

Criteria for revision:

Mobile flap > 2 mm in ICA, flap > 3 mm in the CCA and technical defects causing > 30% luminal ICA stenosis

2.3% (15/650)

Stroke rate

Combined: 0.3% (2/650)

Revised: 0% (0/15)

Mortality rate

Combined: 0.3% (2/590)

*650 cases in 590 patients

Flow abnormality at 2 weeks:

Combined: 3% (2/625*)—ICA occlusion in both cases

Revised: 0% (0/15)

Flow abnormality at 3 months:

Revised: 0% (0/15)

*625 f/u scan available for 650 patients

Mullenix PS

2003

Prospective single center study

100

Routine; DUS in all cases

Criteria for revision:

Surgeon’s discretion

7% (7/100)

Stroke rate

Combined: 2% (2/100)

Both stroked occurred in cases with an abnormal completion scan that was left unrepaired. However, one stroke was contralateral and likely unrelated

Mortality rate

Combined: 0% (0/100)

Re-stenosis* at follow up (range 6–45 months)

Combined: 10/100

3 of these regressed and 1 was high grade (> 80%)

*Defined as > 50%

Bandyk DF

1994

Prospective single center study

368 in total, of which 210 were CEA’s

Routine; DUS in all cases

Criteria for revision:

Defect on B mode with a PSV > 150 cm/s in CCA, ICA or ECA

8.1% (17/210)

Combined: 0% (0/210)

Not specified

Not specified