Faculty Bibliography

OBJECTIVE: Due to the inherent risks, deficiencies and cost associated with contrast arteriography (CA), our group has been utitilizing duplex arteriography (DA) for evaluating the arteries of the lower extremity for patients undergoing lower extremity revascularization. In an effort to further explore the strengths and weaknesses of DA, we reviewed our evolving experience with DA from January 1, 1998, to January 1, 2005. PATIENTS AND METHODS: The arterial segments starting from mid-abdominal aorta to the pedal arteries were studied in cross-sectional and longitudinal planes using a variety of scanheads of 7-4, 10-5, 12-5, 5-2 and 3-2 MHz extended operative frequency range to obtain high-quality B-mode, color and power Doppler images as well as velocity spectra. In 906 patients, 1,020 duplex arteriograms were obtained. The ages ranged from 30-98 years old with a mean of 73+/-11 (SD) years. Fifty percent of the patients were diabetics. Indications for the examination included: tissue loss (409), rest pain (221), claudication (310), acute ischemia (74), popliteal aneurysm (45), SFA aneurysm (2), abdominal aortic aneurysms (AAA) (10) and failing bypass (55). Prior procedures had been performed in 262. DA was performed by six technologists (4 of whom are MDs). In all, 207 DA were performed intraoperatively and the remainder, preoperatively. RESULTS: The resultant procedures based upon DA included: bypass to the popliteal artery (262) and bypass to an infrapopliteal artery (325), endovascular procedures (363), thrombectomy (11), embolectomy (9), inflow bypass procedures to the femoral arteries (46), debridment (4), amputation (8) and no intervention (75). The areas not visualized well included: iliac (73), femoral (26), popliteal (17), and infrapopliteal (221). Additional imaging after DA was deemed necessary in 102 cases to obtain enough information to plan lower extremity revascularization. Factors associated with increased need to obtain CA included: DM (p<.001), infrapopliteal calcification (p<.001), older age (p = .01) and limb threatening ischemia (p<.001). Factors not associated with the need to obtain CA included: which technologist performed the exam, whether the technologist has a medical degree and whether the patient underwent prior revascularization. CONCLUSIONS: In 90% of patients reviewed, DA is able to obtain the needed information to plan lower extremity revascularization. Severe tibial vessel calcification is the most common cause of an incomplete DA exam and determines when alternative imaging modalities need to be obtained.

OBJECTIVE: Following contemporary trend, various vascular interventions being performed in the office. We describe our office experience with radiofrequency ablation (RFA) of incompetent perforating veins (IPV) and duplex-guided balloon angioplasties of failing/nonmaturing arterio-venous fistulas (AVF). DUPLEX-GUIDED BALLOON ANGIOPLASTIES OF AVF: Eighteen patients with 20 failing arterio-venous (AV) fistulas underwent office duplex-guided balloon angioplasties. Thirteen procedures (65%) were on non-maturing fistulas and the remaining 7 (35%)--in dialyzed patients. Sheath insertion, wire and balloon passage and inflation were guided by duplex only. RFA OF IPVS: We performed 25 radiofrequency ablations of 49 IPVs. Early follow-up scan confirmed total occlusion of 45 (92%) treated IPVs. Patients gender, CEAP class, perforator diameter or GSV patency did not correlate with current procedure failure. CONCLUSION: Excellent duplex imaging quality and technical advances in endovascular tools allowed us safely perform AVF balloon angioplasties and RFA of IPVs in the office.

Currently, the value of stenting during femoropopliteal balloon angioplasty (FPBA) remains unclear. Herein we evaluate the patency rates of successful duplex-guided balloon angioplasty (DAGBA) alone versus suboptimal DAGBA followed by stenting and the prestenting dissection versus recoil as potential indicators of stent success or failure. Over a period of 27 months, we performed 291 duplex-guided FPBAs (194 stenoses; 97 occlusions) on 244 limbs in 220 patients. Disabling claudication was the indication in 67%. Critical limb ischemia was the indication in the remaining 33%. Self-expanding nitinol stents were used when plaque dissection and/ or recoil caused diameter reduction > or = 40%. Serial follow-up duplex scans were obtained. Severe restenosis (> 70%) was measured by B-mode imaging and a peak systolic velocity ratio > 3. Follow-up ranged from 1 to 41 months (mean 10 +/- 8.3 months). The overall mean interval for restenosis and occlusion was 6.5 +/- 4.2 months and 5.6 +/- 6.1 months, respectively. Stents did affect overall patency results compared with not using stents. Reasons for stenting were plaque recoil, dissection, or both in 98 (53%), 44 (24%), and 42 (23%) cases, respectively. Six-month patency was 59%, 94%, and 69%, respectively. The difference between plaque recoil and dissection was significant (p<.04). The use of stents during FPBA may be associated with balloon angioplasty site failure in the femoropopliteal segment. To our knowledge, this is the first report ever to document plaque recoil as a predictor of balloon angioplasty site failure notwithstanding stent placement.

Acute venous disorders include deep venous thrombosis, superficial venous thrombophlebitis, and venous trauma. Deep venous thrombosis (DVT) most often arises from the convergence of multiple genetic and acquired risk factors, with a variable estimated incidence of 56 to 160 cases per 100,000 population per year. Acute thrombosis is followed by an inflammatory response in the thrombus and vein wall leading to thrombus amplification, organization, and recanalization. Clinically, there is an exponential decrease in thrombus load over the first 6 months, with most recanalization occurring over the first 6 weeks after thrombosis. Pulmonary embolism (PE) and the post-thrombotic syndrome (PTS) are the most important acute and chronic complications of DVT. Despite the effectiveness of thromboembolism prophylaxis, appropriate measures are utilized in as few as one-third of at-risk patients. Once established, the treatment of venous thromboembolism (VTE) has been defined by randomized clinical trials, with appropriate anticoagulation constituting the mainstay of management. Despite its effectiveness in preventing recurrent VTE, anticoagulation alone imperfectly protects against PTS. Although randomized trials are currently lacking, at least some data suggests that catheter-directed thrombolysis or combined pharmaco-mechanical thrombectomy can reduce post-thrombotic symptoms and improve quality of life after acute ileofemoral DVT. Inferior vena caval filters continue to have a role among patients with contra-indications to, complications of, or failure of anticoagulation. However, an expanded role for retrievable filters for relative indications has yet to be clearly established. The incidence of superficial venous thrombophlebitis is likely under-reported, but it occurs in approximately 125,000 patients per year in the United States. Although the appropriate treatment remains controversial, recent investigations suggest that anticoagulation may be more effective than ligation in preventing DVT and PE. Venous injuries are similarly under-reported and the true incidence is unknown. Current recommendations include repair of injuries to the major proximal veins. If repair not safe or possible, ligation should be performed.

Duplex arteriography may be a potential replacement of preoperative standard contrast arteriography for peripheral arterial imaging in lower extremity revascularization procedures. In patients with chronic or acute ischemia, a well-performed duplex arteriography offers several practical advantages over contrast arteriography: it is noninvasive; it does not require nephrotoxic agents; it is portable and can be done expeditiously; color flow and waveform analysis provide a better estimation of the hemodynamic significance of occlusive disease; it allows direct visualization of the entire artery and not only of the lumen thus enabling plaque characterization; with color flow and power Doppler techniques, it is possible to identify patent arteries subjected to very low flow states; and it can detect occluded arterial aneurysms thereby avoiding unnecessary attempts at thromboembolectomies. High-quality arterial ultrasonography performed by a highly skilled and well-trained vascular technologist may represent an alternative to conventional arteriography for patients in need of primary or secondary lower extremity revascularization.

The conventional balloon angioplasty of infrainguinal arteries requires the use of fluoroscopy and injection of contrast material. We attempted to perform 360 balloon angioplasties of the superficial femoral (SFA) and/or popliteal arteries under duplex guidance in 274 patients to avoid the nephrotoxic effect of contrast and eliminate or minimize radiation exposure. Critical ischemia was the indication in 35% of cases and severe claudication in 65%. Infrapopliteal angioplasties of 80 arteries were attempted in 54 cases (15% of all cases) in order to improve the run-off after completion of femoral-popliteal angioplasties. For femoral-popliteal segment, overall technical success was 95% (342/360 cases). For infrapopliteal arteries, technical success was achieved in 77 of 80 cases, with an overall success rate of 96%. Twelve-month patency rates for TASC class A, B, C, and D lesions were 90%, 59%, 52%, and 46%, respectively. PAVF <100 mL/min was the most powerful predictor of 30-day and 6-month arterial thrombosis following femoral/popliteal balloon angioplasties.Duplex-guided balloon angioplasty and stent placement appears to be a safe and effective technique for the treatment of femoral-popliteal and infrapopliteal arterial occlusive disease. PAVF <100 mL/min is the most powerful predictor of early (30 days) and midterm (6-month) arterial thrombosis following femoral-popliteal interventions.

Endovascular repair of failing infrainguinal bypasses can effectively improve patency and limb salvage results in selected cases. We attempted to perform balloon angioplasties of 47 failing grafts in 3 patients under duplex guidance to eliminate or diminish the use of nephrotoxic contrast material and radiation exposure. The technical success was 98% (46/47 cases). One case of the outflow lesion in the plantar artery could not be traversed with the guidewire due to extreme tortuosity. Overall local complications rate was 4% (2 cases). One vein bypass pseudoaneurysm caused by rupture with cutting balloon was repaired by patch angioplasty and 1 SFA pseudoaneurysm at the puncture site required open repair. Overall 6- and 12-month primary patency rates were 70% and 50%, respectively.Duplex guidance of failing infrainguinal arterial bypasses appears to be an effective treatment modality. Advantages include visualization of the puncture site, accurate selection of the proper size balloon, and confirmation of the adequacy of the technique by hemodynamic and imaging parameters. Additional benefits are avoidance of radiation exposure and contrast material in most cases.

Carotid artery balloon angioplasty and stenting (CBAS) is gaining popularity as an adequate alternative to carotid endarterectomy (CEA) in selected patients. Unfortunately, the substantial amount of contrast media used for CBAS, traditionally performed under fluoroscopic guidance, may impair renal function in patients with diabetes or ones with elevated serum creatinine. We attempted to apply duplex assistance to limit or eliminate the use of contrast during CBAS. Fluoroscopy was utilized to assist manipulation of the guidewire into the aorta and the common carotid artery, and positioning of the distal cerebral protection device. Selective catheterization of the internal and external carotid arteries was performed under ultrasound guidance. Balloons and stent were successfully deployed with ultrasound guidance alone in all cases. Appropriate stent apposition and arterial patency were confirmed by duplex in all cases. One ipsilateral stroke (2.9%) occurred intraoperatively with almost complete clinical recovery in 4 months. On-table biplanar cerebral arteriogram performed in this patient was normal. No early (30-day) mortalities were in the series. Duplex-assisted CBAS is feasible and may reduce the need for contrast media in selected patients with high risk for renal failure. Additional advantages include guidance of the femoral puncture, precise position of the balloon and stent and B-mode and hemodynamic confirmation of the adequacy of the technique.

OBJECTIVE: We have investigated whether popliteal artery volume flow (PAVF) measured immediately after balloon angioplasties of the superficial femoral artery-popliteal segments (SFA/POP) was predictive of early (30 days) and mid-term (6 months) arterial thrombosis. METHODS: During the last 24 months, 203 patients (56% men) with a mean age of 73 +/- 9 years had 268 duplex-guided balloon angioplasties of the SFA/POP. Critical ischemia was the indication in 36%. Group I included 176 (66%) with stenoses, and group II had 92 (34%) with occlusions. All patients had completion duplex examinations that included three measurements of PAVF of below-the-knee popliteal artery. RESULTS: Early (30 days) thrombosis of the treated femoropopliteal arterial segment developed in 10 patients (3.7%), three in group I (1.7%) and seven in group II (7.6%; P < .04). All 10 cases of early thrombosis were in patients with TransAtlantic Inter-Society Consensus (TASC) class C (6/185, 3.2%) and D (4/26, 15%) lesions. Moreover, the 19% incidence (n = 4) of early thrombosis in patients with PAVF <100 mL/min (mean, 73 +/- 24 mL/min; range, 20 to 99 mL/min) was higher compared with the 2.4% rate for patients with higher flows (mean, 176 +/- 60 mL/min; range, 100 to 450 mL/min; P < .01). At 6 months of follow-up, femoropopliteal occlusions had developed in nine more patients, and it became apparent that low PAVF measurements were still predictive of thrombosis (29%) when compared with higher PAVF cases (6%; P < .002). Log-rank comparison of survival curves for cumulative primary stenosis-free patency in group I and group II demonstrated a statistically significant difference (P < .02). PAVF <100 mL/min and TASC classification were significant predictors of early (30 days) and mid-term (6 months) arterial thrombosis after femoropopliteal angioplasties. PAVF was the most powerful predictor of arterial thrombosis. The respective 6-month and 12-month limb salvage rates were 98% and 94% for patients with claudication and 88% and 85% for those with limb-threatening ischemia (P < .0001). CONCLUSIONS: Our results demonstrate that low PAVF is the most powerful predictor of early (30 days) and mid-term (6 months) arterial thrombosis after femoropopliteal interventions. In the presence of a low postprocedure PAVF (<100 mL/min), one may consider not reversing the heparin or using intermittent calf compression, or both, to augment the arterial flow.