Angiography

The introduction of the angiographic intraoperative control in the intraoperative field was justified by an early experience from Renwick et al. [26]: when routinely used on any type of lower extremity surgical operation, it showed technical defects in 27% of the patients. This dramatically

Fig. 1.12.1 A below-knee femoropopliteal by-pass done a few months before it thrombosed acutely. At reintervention patency was restored by using Fogarty catheters. Completion angiogra-phy showed a patent tibioperoneal trunk. Run-off was provided through the tibialis posterior and peroneal

decreased the early thrombosis rate from 18% to 0%. A landmark paper from Courbier et al. [7] reported on more than 1800 arterial procedures where a completion angi-

Table 1.12.3 Factors contributing to graft occlusion with time

Cause

Time from implant

0-30 days

1-18 months

months to 5 years

Operative technique

++++

-

-

Graft surface thromboge-nicity

++

+

-

Poor outflow

++

+

-

Obstructive venous disease

++

+

-

Neointimal fibroplasias

-

+++

-

Graft structural abnormalities (vein)

-

+++

++

Graft structural abnormalities (prosthetic graft)

-

-

++

Progressive atherosclerosis

-

+

++++

Modified from [35]

Modified from [35]

ography was performed. Among by-passes in the lower extremities, angiography showed technical problems in 2.2% of the grafts. Papers published later confirmed the role of completion angiography in the improvement of the patency of the reconstructions and its superiority to physical examination and CW Doppler. Mills et al. [20] performed a completion angiography at the end of the procedure on all but one of the 214 reversed vein by-passes. In 18 cases a technical error was shown (8%); femoro-popliteal grafts had fewer defects (6%) than femorodistal ones (12%). In only three cases was the presence of a defect suspected on the basis of the physical examination or CW Doppler measurement. Early occlusion occurred in seven cases, but only in two of them was a technical defect found, leading to 90% sensitivity and 98% specificity for angiography. Marin et al. [19] evaluated 78 infrapopliteal by-passes to grade the lesions found at angiography into four classes. Six class I lesions did not require revision. Eighteen by-passes in classes I and II received minimal treatment, such as urokinase or papaverine infusion. Surgical revision was performed on 15 grade III lesions (total cut-off of the graft or outflow artery, opacification or irregular intraluminal filling defects of distal by-pass or outflow artery). When compared to 39 by-passes with no visible defect (class 0) classes I and II together showed no difference in their patency rates at 30 days and 1 year (87% and 82% versus 87% and 79%). Grade III lesions had poorer results (33% and 27%) despite surgical revision. The authors concluded that angiography might not always be able to define appropriately the extent of the problem associated with the defect. Later, angiography was further improved with the introduction of digital subtraction. However, this technique requires expensive equipment, trained personnel and a longer time to be performed. The advantage of angiography is the ability to provide information on both the reconstruction and distal run-off. This fact is particularly important in the emergent procedures: in these cases the surgeon often faces an unknown vascular tree, where the poor status due to the underlying disease can compromise any successful attempt to solve the acute problem (Fig. 1.12.1).

sults were encouraging, but the technology was still poor, not allowing different defects to be distinguished, such as valve cusps or the presence of a fistula [32]. With the introduction of duplex scanners and colour duplex scanners, the accuracy of this method increased.

MacKenzie, of the McGill University in Montreal, reported on 78 infra-inguinal by-passes where duplex was used as an intraoperative control [18]. The cut-off used to determine the need for re-intervention was: PSV > 200 cm/s and < 45 cm/s and a velocity ratio >2. Thirty bypasses met the criteria for revision, but only 12 were reopened. In the latter group, surgeons felt the defects were reversible or not correctable. When they analysed the 6-months primary and secondary patency for the three groups, they found a significant difference between the first two groups (93% and 97% for the normal and 91% and 100% for the revised) when compared to the group that was not revised (53% and 71%); this result was confirmed by the log-rank test on the Kaplan-Meier curves (p<0.001).

Doppler and later duplex have been extensively studied by the group of Bandyk. The landmark paper reported in 2000 on 626 infra-inguinal procedures receiving intraoperative duplex at the end of the procedure [16]. The protocol required a 30-mg papaverine injection inside the by-pass to be performed before scanning to obtain maximum vasodilatation of the run-off, thus enhancing the sensitivity of the test. Table 1.12.4 shows the classifica-

Col 74% Mapl FP Basso FRJ2500 Hi Opl-ikissffiVMMl

PSV -ri2im!s MOV 7 0tm's

IP 10.5J

A PER SX

A PER SX

Was this article helpful?

0 0
Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

Get My Free Ebook


Post a comment