Table 2 Summary of results from studies evaluating IODUS in LEB

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

Taze-Woei T

2014

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

2032

Selective: completion imaging performed in 67% of cases (1368/2032). Angiography performed in in 89% and DUS in 11% of cases

Criteria for revision:

Surgeons discretion

No breakdown results for completion imaging strategy (i.e., DUS and angiography)

Selective vs routine completion imaging

The surgeon’s strategy of performing routine vs selective CIM was not associated with primary graft patency at discharge (RR, 0.8; 95% CI 0.6–1.1; p = .31) and at 1-year follow-up (RR, 1.1; 95% CI 0.9–1.2; p = .56)

Completion imaging vs no completion imaging

In multivariate models, completion imaging was not associated with improved primary graft patency at discharge (OR, 1.1; 95% CI 0.7–1.7; p = .64) or at 1 year (OR, 0.9; 95% CI 0.7–1.2; p = .47)

Gilbertson JJ

1991

Prospective single center study

20

Routine. Blinded comparison of DUS, angiography and angioscopy

Criteria for revision:

Residual valve cusp: Doubling of PSV or marked spectral broadening compared with adjacent graft. PSV < 40 cm/s or > 150 cm/s

Unligated side branch: B-mode or color flow image directed away from lumen

Anastomotic stenosis: High velocity jet or turbulence

unknown

Residual cusps (n = 9)

Angiography: (2/9)

Angioscopy: (9/9)

DUS: (1/9)

Unligated side branch (n = 32)

Angiography: (14/32)

Angioscopy: (21/32)

DUS: (4/32)

Anastomotic stenosis (n = 0)

Angiography: (4/0), FP rate 20%

Angioscopy: (0/0)

DUS: (2/0), FP rate 10%

Denominator = confirmed on exploration

Descriptive studies

Bandyk DF

1994 (series from 1990–1993)

Prospective single center study

368 in total, of which 135 were bypasses

Routine

Completion arteriography was also performed in 81% of cases (110/135)

Criteria for revision:

Severe (PSV > 180 cm/s with broadening or PSVR 2.5 to 4) or high grade (PSV > 300 cm/s or PSVR > 4) stenosis velocity spectra in the presence of anatomic lesion on DUS

14.1% (19/135)

Within 30 days

Combined graft thrombosis:

0.7% (1/135)

Combined secondary intervention: 2.2% (3/135)

Due to a lesion and low graft flow

Combined assisted patency: 100% (135/135)

All of the four cases had residual lesions on completion DUS. 60% (3/5) unrepaired vein graft lesions required revision. No patients with a normal completion scan required a secondary procedure during a minimum of 2-month follow-up

Completion angiography did not demonstrate any additional significant lesions

Bandyk DF

1996 (series from 1991–1995)

Prospective single center study

275

Routine

Criteria for revision:

Severe (PSV > 180 cm/s with broadening or PSVR 2.5 to 4) or high grade (PSV > 300 cm/s or PSVR > 4) stenosis velocity spectra in the presence of vessel lumen defect or narrowing

Lesions associated with low graft flow

Segments with borderline stenosis (125–180 cm/s) were rescanned after additional papaverine administration—if PSV increased to > 200 cm/s in a normal diameter vein or anastomosis revision was performed

When increased velocities (> 180 cm/s) were measured in outflow tibial arteries but the velocity ratio was less than < 2.5, an angiogram was performed confirm patency beyond distal anastomosis

15.6% (43/275)

Within 30 days

Graft thrombosis

Overall: 1.1% (3/275)

Unrepaired flow abnormality (PSV < 180 cm/s): 4% (1/25)

Secondary intervention

Unrepaired flow abnormality (PSV < 180 cm/s): 16% (4/25)

Assisted patency

Overall: 100% (275/275)

Mortality:

Overall: 1.1% 3/275

Between 30 and 90 days

Graft thrombosis

Normal imaging*: 0.4% (1/235)

Unrepaired flow abnormality (PSV < 180 cm/s): 4% (1/25)

Secondary intervention

Normal imaging*: 2.6% (26/235)

Unrepaired flow abnormality (PSV < 180 cm/s): 36% (9/25)

Abnormal imaging after repair: 40% (6/15)

Overall graft thrombosis/secondary intervention in normal imaging vs Unrepaired flow abnormality; p < 0.001

60% 15/25 uncorrected abnormalities had thrombosis or re-intervention in first 3 months

*202 without repair, 33 with repair

Johnson BL

2000 (series from 1991–1998)

Retrospective single center study

Routine

Criteria for revision:

Same criteria as Bandyk (1996). However, low flow and unrepaired graft lesions were managed with specified antithrombotic regimen or adjunctive procedure

Normal graft flow (> 45 cm/s, low PVR defined as antegrade flow throughout pulsed cycle)- dextran + aspirin (325 mg/day)

Low flow and low PVR- heparin + dextran + aspirin

Low flow and high PVR- adjunct procedure (e.g., arteriovenous fistula or jump graft to another outflow artery) if possible. If not treated as low flow + low PVR

Low flow graft stenosis (> 200 cm/s at site of stenosis- repair stenosis + heparin + dextran + aspirin

15.3% (96/626)*

Revision of 99 graft segments for stenosis and 5 adjunct procedures to improve graft flow *

*104 defects in 96 bypasses

Within 30 days (secondary intervention rate)

Combined: 4.2% (26/626)

Normal flow: 1.1% (5/464)

Normal flow (revised graft): 1.5% (1/67)

Residual flow abnormality (revised graft): 34.5%(10/29)

Unrepaired flow abnormality): 13.2% (7/53)

Low flow (but no stenosis): 23.1% (3/13)

Between 30 and 90 days (secondary intervention rate)

Combined: 4.3% (27/626)

Normal flow: 1.3% (6/464)

Normal flow (revised graft): 1.5% (1/67)

Residual flow abnormality (revised graft): 10.3% (3/29)

Unrepaired flow abnormality: 24.5% (13/53)

Low flow (but no stenosis): 15.4% (2/13)

Total (within 90 days) (secondary intervention rate)

Combined: 8% (51/626)

Normal flow: 2.4% (11/464)

Normal flow (revised graft): 3%(2/67)

Residual flow abnormality (revised graft): 44.8% (13/29)

Unrepaired flow abnormality: 37.7% (20/53)

Low flow (but no stenosis): 38.5% (5/13)

MacKenzie KS

1999

Retrospective single center study

78

Selective

Criteria for revision:

Surgeons discretion

15.3% (12/78)

Within 30 days (n = 76):

Secondary intervention rate/primary patency/secondary patency

Normal flow: 1.3%/100%/N.A

*Revised graft: 8.3%/100%/N.A

Unrepaired flow abnormality: 11.1%/83%/unknown

Between 30 days and an average intermediate follow-up of 7.4 months (n = 72)

Secondary intervention rate /primary patency/secondary patency

Normal flow: 1.3%/93%/97%

Revised graft: 8.3%/91%/100%

Unrepaired flow abnormality: 11.1%/53.1%/71.1%

Statistical significant difference in patency rates when comparing unrepaired flow abnormality to normal flow (p < 0.001) or to repaired group (p < 0.001)

*Repeat scan normal at completion in all 12 cases