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27.13 Stenting occluded superficial femoral arteries
23rd World Congress of the ISCVS the signal. Spectral profile PW Doppler analysis showed a better definition of the shape without increase of peak velocity. In three cases, further information was provided: in two patients the echo-contrast examination revealed the persistence of flow within the aneurysm sac and in one patient the incomplete adhesion to the arterial wall was demonstrated. Conclusion: The follow-up of endovascular prostheses represents one of the new goals of ultrasound. These preliminary results seem to support an important role of echoenhancers in this field.
27.13 Stenting Occluded Superficial Femoral Arteries I.L. GORDON, R.C. CONROY J.M. TOBlS and S.E. WILSON, Long Beach, California, USA We are evaluating a technique for recanalizing chronic superficial femoral occlusions entailing wire penetration of the occlusion, balloon angioplasty, and deployment of selfexpanding Wall-Schneider stents, followed by repeat angiography at 6 months with supplemental endovascular intervention as required for recurrent stenosis. Eligible subjects had to have suprageniculate popliteal reconstitution with at least one patent tibia1 runoff vessel. Aggressive anticoagulation with heparin for the first 72 h after the procedure followed by coumadin for the first months was implemented. This procedure was applied to a total of 45 limbs in 34 patients. The mean occlusion length was 15 + 12cm. In four cases the attempt to recanalize was unsuccessful. Primary patency, assisted primary patency (after additional endovascular therapy in the absence of occlusion), and secondary patency rates were obtained with duplex ultrasound in limbs successfully recanalized (mean follow-up = 12 -c 7 months). Patency
Months Number of limbs Primary
2Assisted primary
Secondary
6 12
80.0
94.9 84.0
39 25
89.7 40.0
Complications included one early death from retroperitoneal hemorrhage and two deaths from unrelated causes during follow-up. Two emergent thrombectomies after recanalization were performed, with a compartment syndrome developing in one case. One subject with a patent stent required a Symes amputation. One subject whose recanalization was unsuccessful went on to BK amputation. TWO bypasses were required after stent thrombosis. One of these subjects required BK amputation after bypass failure. Overall, early results with this endovascular method are sufficiently promising to justify further clinical evaluation.
27.14 Vascular Laboratory Surveillance After Femoropopliteal Balloon Dilatation in 158 Patients K.A. MYERS, M .J. DENTON, C. HOLDAWAY and S. WOODS, Melbourne, Australia Initially successful femoropopliteal balloon dilatation was followed by vascular laboratory surveillance in 158 consent-
140
ing patients for a minimum 2 years. Claudication was the indication in 80%, and stenosis was the preoperative pathology in 85%. Surveillance was by serial duplex ultrasound scans and anklelbrachial pressure indices (ABI). Late failure was defined as recurrent stenosis requiring reintervention or occlusion. Late failure had occurred in 15% of these procedures by 2 years, due to restenosis or occlusion in approximately equal numbers. A maximum peak systolic velocity (PSV) >250crr&ec in the treated segment at the last test best predicted late failure with a specificity of 86% and sensitivity of 74%. A resting ABI ~0.75 also predicted failure but with lower accuracy. Other parameters of duplex scans or ABIs were not predictive. Stenosis as defined by PSV >250cm/sec was present from the first test suggesting residual disease in approximately one-third. or developed later indicating recurrence in approximately two-thirds. Surveillance appears to be of value, particularly to reveal late restenosis, but further studies are required to determine when to reintervene and whether this improves secondary success rates.
27.15 Balloon Dilatation of the Human I&arena1 Abdominal Aorta: How Much Oversizing is Safe? X. CHAUFOUR, G.H. WHITE, W YU,]. MAY, J. HARRIS and M .S. STEPHEN, Sydney,Australia Introduction: The aim of this study was to evaluate the effects of aortic balloon catheters on the aortic wall during balloonexpansion deployment of endoluminal grafts in the treatment of infrarenal aortic aneurysm. The wall tension resulting from outward fluid pressure is proportional to the pressure and to the diameter. Because balloon hoop stress is proportional to balloon diameter, a larger balloon has more dilating power, which has the potential to cause significant damage to the aortic wall. Methods: Large dilatation balloons were expanded within the aorta of 41 cadavers. The true diameter of each balloon was calibrated from 1 to 4 atmospheres. The distal end of the balloon catheter was positioned at renal artery level and inflated to 0.15 Atm (1lOmm Hg) to appreciate the diameter of the aorta at physiological blood pressure; testing was continued with the same balloon catheter or a smaller balloon catheter to evaluate different oversizing groups. Measurements of the infrarenal aorta were recorded under control of a pressure transducer from 0.15 Atm to 2.5 Atm. After opening the aorta, the macroscopic appearances were recorded as to degree of calcifications and severity of atheroma. Damage was classified with respect to: (i) dissection of intima and media, (ii) fracture of atherosclerotic plaque, (iii) integrity of adventitia. Results: In group I (no calcification), no macroscopic abnormalities were detected up to 6 m m oversized balloon, at which size dissection and rupture of the aorta started to occur. In group II (minor calcification), fracture of atherosclerotic plaque occurred in six of 12 aortas (50%) with 2.5-4mm oversized balloons; rupture of the adventitia appeared with 7 m m oversiz. In group III (severe calcification), fracture of atherosclerotic plaque occured in six of seven (85%) with 2.5-4 m m oversized balloon, and rupture of the aorta occured at 6 m m oversizing. Conclusions: The risk of fracture of atherosclerotic plaque is greater when the infrareal aorta is severely calcified. The
CARDIOVASCULAR SURGERY SEPTEMBER 1997
27.13 Stenting Occluded Superficial Femoral Arteries I.L. GORDON, R.C. CONROY J.M. TOBlS and S.E. WILSON, Long Beach, California, USA We are evaluating a technique for recanalizing chronic superficial femoral occlusions entailing wire penetration of the occlusion, balloon angioplasty, and deployment of selfexpanding Wall-Schneider stents, followed by repeat angiography at 6 months with supplemental endovascular intervention as required for recurrent stenosis. Eligible subjects had to have suprageniculate popliteal reconstitution with at least one patent tibia1 runoff vessel. Aggressive anticoagulation with heparin for the first 72 h after the procedure followed by coumadin for the first months was implemented. This procedure was applied to a total of 45 limbs in 34 patients. The mean occlusion length was 15 + 12cm. In four cases the attempt to recanalize was unsuccessful. Primary patency, assisted primary patency (after additional endovascular therapy in the absence of occlusion), and secondary patency rates were obtained with duplex ultrasound in limbs successfully recanalized (mean follow-up = 12 -c 7 months). Patency
Months Number of limbs Primary
2Assisted primary
Secondary
6 12
80.0
94.9 84.0
39 25
89.7 40.0
Complications included one early death from retroperitoneal hemorrhage and two deaths from unrelated causes during follow-up. Two emergent thrombectomies after recanalization were performed, with a compartment syndrome developing in one case. One subject with a patent stent required a Symes amputation. One subject whose recanalization was unsuccessful went on to BK amputation. TWO bypasses were required after stent thrombosis. One of these subjects required BK amputation after bypass failure. Overall, early results with this endovascular method are sufficiently promising to justify further clinical evaluation.
27.14 Vascular Laboratory Surveillance After Femoropopliteal Balloon Dilatation in 158 Patients K.A. MYERS, M .J. DENTON, C. HOLDAWAY and S. WOODS, Melbourne, Australia Initially successful femoropopliteal balloon dilatation was followed by vascular laboratory surveillance in 158 consent-
140
ing patients for a minimum 2 years. Claudication was the indication in 80%, and stenosis was the preoperative pathology in 85%. Surveillance was by serial duplex ultrasound scans and anklelbrachial pressure indices (ABI). Late failure was defined as recurrent stenosis requiring reintervention or occlusion. Late failure had occurred in 15% of these procedures by 2 years, due to restenosis or occlusion in approximately equal numbers. A maximum peak systolic velocity (PSV) >250crr&ec in the treated segment at the last test best predicted late failure with a specificity of 86% and sensitivity of 74%. A resting ABI ~0.75 also predicted failure but with lower accuracy. Other parameters of duplex scans or ABIs were not predictive. Stenosis as defined by PSV >250cm/sec was present from the first test suggesting residual disease in approximately one-third. or developed later indicating recurrence in approximately two-thirds. Surveillance appears to be of value, particularly to reveal late restenosis, but further studies are required to determine when to reintervene and whether this improves secondary success rates.
27.15 Balloon Dilatation of the Human I&arena1 Abdominal Aorta: How Much Oversizing is Safe? X. CHAUFOUR, G.H. WHITE, W YU,]. MAY, J. HARRIS and M .S. STEPHEN, Sydney,Australia Introduction: The aim of this study was to evaluate the effects of aortic balloon catheters on the aortic wall during balloonexpansion deployment of endoluminal grafts in the treatment of infrarenal aortic aneurysm. The wall tension resulting from outward fluid pressure is proportional to the pressure and to the diameter. Because balloon hoop stress is proportional to balloon diameter, a larger balloon has more dilating power, which has the potential to cause significant damage to the aortic wall. Methods: Large dilatation balloons were expanded within the aorta of 41 cadavers. The true diameter of each balloon was calibrated from 1 to 4 atmospheres. The distal end of the balloon catheter was positioned at renal artery level and inflated to 0.15 Atm (1lOmm Hg) to appreciate the diameter of the aorta at physiological blood pressure; testing was continued with the same balloon catheter or a smaller balloon catheter to evaluate different oversizing groups. Measurements of the infrarenal aorta were recorded under control of a pressure transducer from 0.15 Atm to 2.5 Atm. After opening the aorta, the macroscopic appearances were recorded as to degree of calcifications and severity of atheroma. Damage was classified with respect to: (i) dissection of intima and media, (ii) fracture of atherosclerotic plaque, (iii) integrity of adventitia. Results: In group I (no calcification), no macroscopic abnormalities were detected up to 6 m m oversized balloon, at which size dissection and rupture of the aorta started to occur. In group II (minor calcification), fracture of atherosclerotic plaque occurred in six of 12 aortas (50%) with 2.5-4mm oversized balloons; rupture of the adventitia appeared with 7 m m oversiz. In group III (severe calcification), fracture of atherosclerotic plaque occured in six of seven (85%) with 2.5-4 m m oversized balloon, and rupture of the aorta occured at 6 m m oversizing. Conclusions: The risk of fracture of atherosclerotic plaque is greater when the infrareal aorta is severely calcified. The
CARDIOVASCULAR SURGERY SEPTEMBER 1997