Bilateral brachial artery occlusion decreases internal carotid artery volume flow: a simple adjunct for cerebral protection?

PURPOSE: To investigate if a decrease in internal carotid artery (ICA) blood flow occurs with bilateral brachial artery occlusion (BBO), which may improve the effectiveness of cerebral protection devices during carotid interventions. METHODS: Thirty-two asymptomatic patients (21 men; mean age 67 years) with carotid atherosclerosis between 15% and 79% were enrolled in the study. Carotid duplex ultrasound was followed by volume flow rate (VF) determination in the right ICA, external carotid (ECA), and vertebral arteries. After baseline values were obtained, BBO was induced by bilateral arm pressure cuff inflation to 30 mmHg over the systolic pressure for no more than 3 minutes. VF measurements were repeated. RESULTS: Seventeen patients (responders) had an ICA VF decrease from 406+/-109 mL/min (+/-SD) to 303+/-90 mL/min (p=0.005), while 15 patients (nonresponders) had no significant change in their ICA VF (340+/-192 versus 447+/-267 mL/min, p=0.22). In responders, ECA VF increased (190+/-65 to 232+/-125 mL/min), as did vertebral VF (77+/-53 to 95+/-60 mL/min; p>0.05). The ratio of ICA/ECA VF dropped from 2.13 to 1.31 in responders, but did not change in nonresponders. No patient exhibited any neurological symptoms during the study. Post cuff volume flows approximated baseline values. Cerebral magnetic resonance angiograms obtained in 10 responders revealed a complete circle of Willis in 8 (80%), while only 1 (16%) of 6 nonresponders had a complete pathway. CONCLUSIONS: A transient decrease in ICA VF, with concomitant elevations of the ECA and vertebral VFs, occurs with occlusion of the brachial arteries in the setting of a complete circle of Willis. Since no flow reversal occurs, this maneuver is insufficient to provide complete cerebral protection, but it may improve the effectiveness of cerebral protection devices and serve as an adjunctive maneuver in selected cases. Furthermore, changes in ICA VF may prove to be a noninvasive test for evaluating the integrity of the circle of Willis.

Graft patency is not the only clinical predictor of success after exclusion and bypass of popliteal artery aneurysms.

PURPOSE: The traditional measure of success after exclusion and bypass of popliteal artery aneurysm (PAA) is graft patency. In addition to fate of the bypass, we hypothesize that late outcome after surgical treatment of PAA is influenced by completeness of exclusion. METHODS: Thirty patients who underwent 41 reconstructions for PAA over a 10-year period were reviewed. RESULTS: Excluded PAAs were examined with duplex ultrasound scan for size, patency, and patent feeding branches; bypass grafts and native inflow and outflow arteries were examined for patency and size. Thirty-six limbs were available for follow-up (mean follow-up period, 46 +/- 42 months). Only two aneurysms (5.6%) appeared patent on duplex ultrasound scan, but five limbs had patent arterial branches communicating with thrombosed excluded PAAs. PAA diameter decreased from 2.5 +/- 0.8 cm to 1.7 +/- 0.5 cm (P <.0001) in most. However, 12 excluded PAAs (33%) showed significant enlargement from 2.2 +/- 0.9 cm to 2.8 +/- 1.0 cm (P =.002). A quarter of enlarging excluded PAA were associated with new compressive symptoms. Three methods of PAA exclusion were used: proximal and distal ligation with short segment isolation (type 1), proximal and distal ligation with long segment isolation (type 2), and single ligature (type 3). In univariate analysis, type of exclusion significantly influenced late size of excluded PAA (P =.004). Type 1 exclusion was superior to both type 2 and 3 exclusions in producing aneurysm diameter reduction. Type 3 exclusion resulted in aneurysm growth. In addition, excluded aneurysms with visualized feeding branches were associated with significant growth compared with PAAs without feeding branches (P =.006). Graft primary and assisted primary patency rates at 5 years were 86% +/- 9.4% and 92% +/- 7.4%, respectively. Although graft diameter and native donor artery diameter significantly increased, this did not adversely affect graft patency. CONCLUSION: Enlargement of excluded PAA after surgical treatment can cause compressive symptoms. Exclusion requires adequate vascular isolation to prevent late PAA enlargement, with proximal and distal arterial ligation best performed adjacent to the aneurysm. Vein graft enlargement occurs, but this enlargement does not adversely influence patency.