Effect of Duplex Arteriography in the Management of Acute Limb-Threatening Ischemia From Thrombosed Popliteal Aneurysms.

The role of routine use of duplex arteriography to diagnose thrombosis of popliteal artery aneurysm as a cause of acute lower extremity ischemia is investigated. In all, 109 patients (group 1) from 1994 to 1997 and 201 patients from 1998 to 2001(group 2) presenting with acute limb-threatening ischemia were studied. None of the group 1 patients underwent preoperative duplex arteriography, and no diagnosis of acute popliteal artery aneurysm thrombosis was made. Ten patients with acute ischemia due to thrombosed popliteal artery aneurysm were identified in group 2 when preoperative duplex arteriography was routinely performed. Urgent revascularization was performed based on the results of duplex arteriography. Six patients had functioning bypasses with a mean follow-up of 15.6 months. There were 3 deaths, 2 within 30 days and 1 after 2(1/2) years with functioning grafts. One patient was lost to follow-up. Routine use of duplex arteriography may provide the diagnosis and may identify the available outflow vessels for popliteal artery aneurysm.

Infragenicular angioplasty and stenting in the management of critical limb ischaemia: one year outcome following the use of the MULTI-LINK VISION stent.

BACKGROUND: Use of stents following angioplasty for infragenicular lesions appears to be superior to angioplasty alone. We investigated the safety and efficacy of MULTI-LINK VISION stent (Abbott Vascular, Brussels, Belgium) for the treatment of infragenicular lesions in patients with critical limb ischaemia (CLI). METHODS AND RESULTS: During the period between February 2005 and October 2005, fifty patients with CLI (Rutherford 4 and 5) due to infragenicular disease were included in the study. The studied patient population included 28 males (56.0%) and 22 females (44.0%) with a mean age of 76 years (range 59-90 years). The medical history was significant for hypertension in 43 patients (86.0%), diabetes in 23 (46%) and hypercholesterolaemia in 37 (74%) patients. Fourteen patients (28%) admitted to the use of nicotine. Thirty-four (68%) belonged to Rutherford class 4 and 16 were class 5 (32%). All patients underwent clinical evaluation before and after the intervention. A pre-procedure Duplex ultrasound examination followed by angiography and intervention were performed on all patients included in the study. Sixty-two lesions were treated with angioplasty followed by insertion of 68 MULTI-LINK VISION stents. After intervention, patients were followed at one, six and 12 month intervals with clinical examination and arterial duplex study. The survival of the studied population was 83.3%, the limb salvage was 89.3% and primary patency of treated vessel was 62.8% at 12 months. CONCLUSIONS: Treatment of infragenicular lesions in CLI with MULTI-LINK VISION stent is safe and effective with satisfactory limb salvage. The primary patency was acceptable, but less compared to dedicated below the knee devices.

Prospective evaluation of combined upper and lower extremity DVT.

The clinical importance of upper extremity deep venous thrombosis (UEDVT) has been increasingly demonstrated in recent literature. Not only has the risk of pulmonary embolism from isolated upper extremity DVT been demonstrated, but a significant associated mortality has been encountered. Examination of this group of patients has demonstrated the existence of combined upper and lower extremity deep venous thrombosis (DVT) in some patients who exhibit an even higher associated mortality. As a result of this information, it has become the standard practice at this institution to search for lower extremity DVTs in patients found to have acute thrombosis of upper extremity veins. Since January 1999, there have been a total of 227 patients diagnosed with acute UEDVT. Within this group, 211 (93%) patients had lower extremity studies; 45 of these 211 (21%) had acute lower extremity DVTs by duplex examination in addition to the upper extremity DVTs. Overall, there were 145 women, 66 men, and the average age was 70 +/-1.2 (SEM); 22 of these patients had bilateral lower extremity thrombosis (LEDVT), and 8 patients were found to have chronic thrombosis of lower extremity veins. Of the patients with bilateral upper extremity DVTs, there were 3 with bilateral LE acute DVTs. Finally, 8 of the remaining 166 patients (5%) with originally negative lower extremity studies were found to develop a thrombosis at a later date. These data serve to confirm previous studies, on a larger scale, that there should be a high index of suspicion in patients with UEDVT of a coexistent LEDVT.

Impact of duplex arteriography in the evaluation of acute lower limb ischemia from thrombosed popliteal aneurysms.

Acute limb-threatening ischemia from thrombosis may be the initial presentation of popliteal artery aneurysms (PAA) and is associated with amputation rates of 20-30%. Since contrast angiography may miss the diagnosis, the authors suspect that thrombosis of PAA may be an underappreciated cause of acute ischemia. Routine use of duplex arteriography (DA) may aid in the diagnosis and may help identify the outflow vessels with improved results. One hundred and nine patients (group 1) from 1994 to 1997 and 201 patients from 1998 to 2001 (group 2) presenting with acute limb-threatening ischemia were studied. None of the group 1 patients underwent preoperative DA and no diagnosis of acute popliteal artery aneurysm thrombosis was made. Ten patients with acute ischemia due to thrombosed popliteal artery aneurysms were identified in group 2 when preoperative DA was routinely performed. Urgent revascularization based on the results from DA was performed with use of autogenous saphenous vein in all patients. Six patients had functioning bypasses with a mean follow-up of 15.6 months. There were 3 deaths, 2 within 30 days and 1 after 2(1/2) years with functioning grafts. One patient was lost to follow-up. No major amputations were performed. Incidence of thrombosed popliteal artery aneurysms as the cause of acute limb-threatening ischemia is probably underestimated. Routine use of DA may provide the diagnosis and identifies the available outflow vessels. Contrary to previously published reports, urgent revascularization of an acutely ischemic extremity from thrombosed popliteal aneurysm can provide excellent rates of limb salvage.

Effect of ultrasonography in the assessment of carotid artery stenosis.

Although ultrasonography (US) advantageously portrays lumen and wall thickness, velocity criteria have been used primarily to interpret carotid artery stenosis. The relationship of US and velocity measurements was investigated. Peak-systolic and end-diastolic velocities (PSV, EDV) increase exponentially as the lumen of the internal carotid artery narrows and the percent stenosis (%S) increases. We tested the consistency of the, relationship between carotid velocities and US %S in two distinct data sets. One data set was used to obtain regression equations relating velocity parameters and %S based on US. Validation of these equations was conducted using a separate, independent data set. US measurements were classified in 12 %S intervals, PSV, EDV, the ratio of the internal carotid artery to the common carotid artery PSV, and %S were entered consecutively until 10 records for each %S interval were obtained. Regression equations obtained in the first data set were used to predict %S in the second data set. Predicted %S was then compared with actual US %S. The highest correlation in the first data set (r = .89) was between %S and the natural logarithm (In) of PSV. This In PSV -%S equation was then applied to a second data set of an additional 120 carotid duplex images. In the second data set, actual %S and PSV-predicted %S differed by >10% in 38 cases (32%). When all velocity-%S regression equations were used for comparison, differences between actual and at least one velocity-predicted %S were >10% in 19% of the arteries. Conversely, actual %S matched at least one prediction of %S based on velocity data in 81% of the cases. US %S differed significantly from single velocity-based estimates of %S in at least one-third of the cases. On the other hand, four of five US measurements were confirmed by at least one velocity parameter. Emphasis on US, in addition to velocity data, is recommended for the interpretation of duplex US carotid examinations.

Early transposition of the sartorius muscle for exposed patent infrainguinal bypass grafts.

The traditional approach for patent and exposed and infected infrainguinal bypass grafts in the groin has included wide operative debridement and secondary or delayed primary closure. However, this has been associated with significant risk of further contamination and length of stay. The authors reviewed their experience using the wide debridement, sartorius muscle flap transposition, and primary wound closure as an alternative. During the past 5 years, they have had 50 patients with major wound necrosis or infection in the groin or thigh with the graft or native artery being exposed after debridement. This group included 28 men; 74% of the patients had hypertension, 58% had diabetes, and 20% had renal failure. The grafts were split evenly between native vein and prosthetic material. After wide debridement, closure was performed by the vascular surgeon using the sartorius muscle flap. Postoperatively, there was an 8% major amputation rate and a 12% mortality rate in the first 30 days. One patient developed a pseudoaneurysm 5 weeks after placement of the flap. This patient underwent removal of the infected polytetrafluoroethylene graft with ligation of the common femoral artery. None of the procedures have resulted in further systemic or graft sepsis. None have resulted in arterial or graft blowout. Follow-up was for an average of 18 months. Closure of groin and thigh wounds with exposed bypass graft or native artery can be safely performed with the sartorius muscle flap with excellent results. The length of stay of these patients compared to historical controls is acceptable. Furthermore, the chance of infection of the native artery or bypass may be reduced. Familiarity with this simple technique can be a valuable tool for the vascular surgeon.

Duplex arteriography prior to femoral-popliteal reconstruction in claudicants: a proposal for a new shortened protocol.

The standard preoperative duplex arteriography (DA) from the aorta to the pedal vessels is time consuming and may be unnecessary in patients presenting with calf claudication alone. The feasibility of a shortened protocol was evaluated. Of 286 femoral-popliteal reconstruction based on DA during the last 4A years, 79 (28%) were primary operations for calf claudication. Eliminating the aortoiliac portion of the test except for the distal external iliac artery and limiting the scanning of the infrapopliteal vessels to one or two arteries in the leg would significantly shorten the exam. To confirm the adequacy of the inflow tract, we relied on the common femoral artery Doppler waveform analysis and the intraoperative graft pressure upon completion of the bypass. Of the 79 primary femoral-popliteal bypasses, 53 (67%) had triphasic common femoral artery waveform and the remaining 26 had monophasic or biphasic waveforms. Three (6%) of the 53 femoral-popliteal bypasses in the former group had significant pressure gradients measured intraoperatively and were treated with iliac angioplasties and stents for unsuspected stenoses in 2 cases and a covered stent for a common iliac aneurysm in 1 case. Three, two, and one infrapopliteal vessel runoff was observed in 24 (45%), 16 (30%), and 9 (17%) extremities, respectively. Four patients (8%) had significant stenoses (>50%) or occlusion of all three infrapopliteal arteries. Eighty-one percent of the patients would have completed the short protocol had we scanned the peroneal artery initially. An additional 8% would have required scanning of a second vessel (anterior tibial) and only 11%, scanning of all three infrapopliteal vessels. The time interval for completion of short-protocol DA was significantly less than the time for the standard DA (16.2 A+/- 5.2A min vs. 35.1 A+/- 10.6 min) ( p < 0.01). We believe that the proposed short DA protocol combined with intraoperative graft pressure measurements can be used in 94% of the patients who have a patent popliteal artery (>/= 7 cm). It is a totally noninvasive approach that is particularly suitable for vascular technologists and surgeons who wish to start utilizing DA instead of contrast arteriography prior to infrainguinal reconstructions. However, the short protocol does not avert the need for completion arteriography of the inflow arteries and readiness to perform endovascular procedures to correct lesions not suspected by common femoral artery waveform analysis.

A comparison of magnetic resonance angiography, contrast arteriography, and duplex arteriography for patients undergoing lower extremity revascularization.

The objective of this study was to compare magnetic resonance angiography (MRA), contrast arteriography (CA), and duplex arteriography (DA) for defining anatomic features relevant to performing lower extremity revascularizations. From March 1, 2001 to August 1, 2001, 33 consecutive inpatients with chronic lower extremity ischemia underwent CA, MRA, and DA before undergoing lower extremity revascularization procedures. The reports of these tests were compared prospectively and the differences in the aortoiliac segment, femoral-popliteal, and infrapopliteal segments were noted. The vessels were classified as mild disease (<50%), moderate disease (50-70%), severe disease (71-99%), and occluded. These studies and treatment plans based on these data were compared. During this time period, 11 patients were not able to undergo MRA and therefore were excluded from the study. Thirty-three patients were included in this study. These patients underwent 35 procedures, as 2 patients underwent bilateral procedures. The mean age of the 33 patients was 76+/-10 years (SD). Indications for the procedures included gangrene (20), ischemic ulcer (8), rest pain (4), and severe claudication (1). Patients' medical history included diabetes mellitus (25), hypertension (20), and end-stage renal disease (5). No differences were noted between intraoperative findings and CA in this series. Two of the three differences between DA and CA were felt to be clinically significant whereas 9 of the 12 differences between MRA and CA were felt to be clinically significant. On the basis of these data in this series, MRA does not yet seem to be able to obtain adequate data on infrapopliteal segments, at least not for this highly selected population. When severe tibial calcification or very low flow states are identified, CA may be necessary for patients undergoing DA.

Deep venous thrombosis after radiofrequency ablation of greater saphenous vein: a word of caution.

PURPOSE: Radiofrequency ablation (RFA) of the greater saphenous vein (GSV; "closure") is a relatively new option for treatment of venous reflux. However, our initial enthusiasm for this minimally invasive technique has been tempered by our preliminary experience with its potentially lethal complication, deep venous thrombosis (DVT). METHODS: Seventy-three lower extremities were treated in 66 patients with GSV reflux, between April 2003 and February 2004. There were 48 (73%) female patients and 18 (27%) male patients, with ages ranging from 26 to 88 years (mean, 62 +/- 14 years). RFA was combined with stab avulsion of varicosities in 55 (75%) patients and subfascial ligation of perforator veins in 6 (8%) patients. An ATL HDI 5000 scanner with linear 7-4 MHz probe and the SonoCT feature was used for GSV mapping and procedure guidance in all procedures. GSV diameter determined the size of the RFA catheter used. Veins less than 8 mm in diameter were treated with a 6F catheter (n = 54); an 8F catheter was used for veins greater than 8 mm in diameter (n = 19). The GSV was cannulated at the knee level. The tip of the catheter was positioned within 1 cm of the origin of the inferior epigastric vein (first GSV tributary). All procedures were carried out according to manufacturer guidelines. RESULTS: All patients underwent venous duplex ultrasound scanning 2 to 30 days (mean, 10 +/- 6 days) after the procedure. The duplex scans documented occlusion of the GSV in 70 limbs (96%). In addition, DVT was found in 12 limbs (16%). Eleven patients (92%) had an extension of the occlusive clot filling the treated proximal GSV segment, with a floating tail beyond the patent inferior epigastric vein into the common femoral vein. Another patient developed acute occlusive clots in the calf muscle (gastrocnemius) veins. Eight patients were readmitted and received anticoagulation therapy. Four patients were treated with enoxaparin on an ambulatory basis. None of these patients had pulmonary embolism. Initially 3 patients with floating common femoral vein clots underwent inferior vena cava filter placement. Of the 19 limbs treated with the 8F RFA catheter, GSV clot extension developed in 5 (26%), compared with 7 of 54 (13%) limbs treated with the 6F RFA catheter (P =.3). No difference was found between the occurrence of DVT in patients who underwent the combined procedure (RFA and varicose vein excision) compared with patients who underwent GSV RFA alone (P =.7). No statistically significant differences were found in age or gender of patients with or without postoperative DVT (P = NS). CONCLUSION: Patients who underwent combined GSV RFA and varicose vein excision did not demonstrate a higher occurrence of postoperative DVT compared with patients who underwent RFA alone. Early postoperative duplex scans are essential, and should be mandatory in all patients undergoing RFA of the GSV.

Role of duplex arteriography as the sole preoperative imaging modality prior to lower extremity revascularization surgery in diabetic and renal patients.

The limitations and complications associated with contrast angiography (CA) prior to lower extremity revascularization have led to an increased interest in duplex arteriography (DA) as a potential replacement. We report our experience with DA in patients with diabetes and/or chronic renal insufficiency (CRI) that would particularly benefit from a noninvasive approach to preoperative evaluation of the arterial tree. From January 1998 to November 2000, DA was performed in 145 patients with diabetes mellitus and/or CRI prior to 180 arterial reconstructions. One hundred twenty-one procedures were performed on 91 patients with diabetes alone, 41 on 33 patients with diabetes and CRI, and 18 on 15 patients with CRI alone. Patient ages ranged from 36 to 98 years (mean 72 +/- 12 years). Indications for surgery were severe claudication in 33 (18%), rest pain in 37 (21%), nonhealing ischemic ulcers in 52 (29%), and limb gangrene in 58 (32%). Optimal inflow and outflow anastomotic sites were selected according to a diagram based on DA that included arterial tree imaging from mid-aorta to the pedal vessels. Preoperative contrast arteriography was performed in 16 cases (9%) because of extremely poor runoff based on DA and limited visualization of outflow vessels. The distal anastomosis was to the popliteal artery in 89 cases (49%) and to the tibial and pedal arteries in 91 (51%). Intraoperative findings confirmed the preoperative DA results with the exception of one (0.6%) where the distal anastomosis was placed proximal to a significant stenosis requiring an extension graft. The use of DA presents a safe and reliable option to prebypass CA for many patients with diabetes or CRI. The ease of use and favorable patient outcomes achieved by this imaging modality may rival the use of CA for these patients.

Magnetic resonance angiography versus duplex arteriography in patients undergoing lower extremity revascularization: which is the best replacement for contrast arteriography?

OBJECTIVE: In an effort to explore alternatives to contrast material-enhanced arteriography, we compared magnetic resonance angiography (MRA) and duplex arteriography (DA) with contrast arteriography (CA) for defining anatomic features in patients undergoing lower extremity revascularization. METHODS: From August 1, 2001, to August 1, 2002, 61 consecutive inpatients (64 limbs) with chronic lower extremity ischemia underwent CA, MRA, and DA before undergoing lower extremity revascularization procedures. The reports of these tests and images were compared prospectively, and the differences in the iliac, femoropopliteal, and infrapopliteal segments were noted. The vessels were classified as mildly diseased (<50%), moderately diseased (50%-70%), severely diseased (71%-99%), or occluded. The studies and treatment plans based on these data were compared. RESULTS: Mean patient age was 76 +/- 10 years (SD). Indications for the procedures included gangrene (43%), ischemic ulcer (28%), rest pain (19%), severe claudication (9%), and failing bypass (1%). During this period 35 patients were ineligible for the protocol, because they could not undergo MRA (n=27) or angiography (n=8). Of the total 192 segments in the 64 patients (iliac, femoropopliteal, tibial), 17% were not able to be fully assessed with DA, and 7% with MRA. Disagreements with CA and DA were found in the iliac, femoropopliteal, and tibial segments in 0%, 7%, and 14% of cases, respectively, and between CA and MRA in 10%, 26%, and 42% of cases, respectively. Two of 9 differences (22%) between DA and CA were thought to be clinically significant, and 28 of 45 differences (62%) between MRA and CA were thought to be clinically significant. CONCLUSIONS: A review of the data obtained in this series indicates that MRA does not yet seem to yield adequate data, at least in this highly selected population at our institution. When severe calcification is identified, CA may be necessary in patients undergoing DA.

Intraoperative carotid artery duplex scanning in a modern series of 650 consecutive primary endarterectomy procedures.

PURPOSE: Thromboembolic complications after carotid endarterectomy are frequently associated with technical defects. We analyzed the effect of intraoperative duplex scanning in detection of significant but clinically unsuspected technical defects and residual common carotid artery (CCA) disease as a potential source of postoperative transitory ischemic attack (TIA) and stroke. METHODS: From April 2000 to April 2003, 650 consecutive primary carotid endarterectomy procedures were performed in 590 patients at a single institution by two vascular surgeons. Patients included 335 men (57%) and 255 women (43%). Indications for surgery were asymptomatic internal carotid artery (ICA) stenosis (>or=70%) in 464 patients (71%). All procedures were performed with the patient under general anesthesia, with synthetic patch angioplasty in 644 (99.1%). Major technical defects at intraoperative duplex scanning (>30% luminal internal carotid artery stenosis, free-floating clot, dissection, arterial disruption with pseudoaneurysm) were repaired. CCA residual disease was reported as wall thickness (0.7-4.8 mm; mean, 1.7 +/- 0.7) and percent stenosis (16%-67%; mean, 32% +/- 8%) in all cases. Postoperative 30-day TIA, stroke, and death rates were analyzed. RESULTS: There were no clinically detectable postoperative thromboembolic events in this series. All 15 major defects (2.3%) identified with duplex scanning were successfully revised. These included 7 intimal flaps, 4 free-floating clots, 2 ICA stenoses, 1 ICA pseudoaneurysm, and 1 retrograde CCA dissection. Diameter reduction ranged from 40% to 90% (mean, 67 +/- 16%), and peak systolic velocity ranged from 69 to 497 cm/s (mean, 250 +/- 121 cm/s). Thirty-one patients (5%) with the highest residual wall thickness (>3mm) in the CCA and 19 (3%) with the highest CCA residual diameter reduction (>50%) did not have postoperative stroke or TIA. Overall postoperative stroke and mortality rates were 0.3% and 0.5%, respectively; combined stroke and mortality rate was 0.8%. One stroke was caused by hyperperfusion, and the other occurred as an extension of a previous cerebral infarct. No patients had TIAs. Two deaths were caused by myocardial infarction, and one death by respiratory insufficiency. CONCLUSION: We believe intraoperative duplex scanning had a major role in these improved results, because it enabled detection of clinically unsuspected significant lesions. Residual disease in the CCA does not seem to be a harbinger of stroke or TIA.

Protective effect of glycine in mesenteric ischemia and reperfusion injury in a rat model.

PURPOSE: Glycine has a protective effect in renal and skeletal muscle ischemia. The purpose of this study was to evaluate the effect of glycine in mesenteric ischemia and reperfusion injury in a rat model. METHODS: Twenty-four anesthetized male Sprague-Dawley rats were subjected to 1 hour of mesenteric ischemia followed by 2 hours of reperfusion. Control animals received normal saline solution intravenously at 0.01 mL/g of body weight/h during ischemia and reperfusion. Treated animals received glycine at 0.5, 0.75, or 1.0 mg/g of body weight, dissolved in saline solution and infused at 0.01 mL/g/h for 2 hours. Animals were killed at the end of the experiment, and proximal, middle, and distal segments of the small bowel were isolated. Sections of the segments stained with hematoxylin-eosin were subjected to histologic examination (as per modified Chiu grading system) and morphometric analysis consisting of measurement of bowel wall, muscularis and mucosal thickness, epithelial coverage, and villar circumference. Isometric tension responses to electrical stimulation (10, 30, 50, 100 Hz), high doses of potassium (120 mmol/L), and carbachol (0.1, 0.5, 1.0, 5.0 micromol/L) were recorded in a multimuscle chamber. Statistical analysis was performed with unpaired t test and one-way analysis of variance. RESULTS: The middle and distal segments of the small bowel in glycine-treated animals showed better histologic grade compared with saline solution-treated control rats (P <.05). At morphometric analysis, total thickness, mucosal thickness, and villar circumference ratio were well preserved in the middle and distal segments of the small bowel in the glycine-treated group (P <.05). No significant differences were observed in the proximal bowel segments between glycine-treated and control animals, because the proximal segment was not subjected to much ischemia. No differences were noted in percentage of epithelial coverage. Isometric tension responses evoked by electrical stimulation were greater (P <.05) in the middle and distal segments treated with glycine as compared with control segments. Carbachol-evoked contractions were stronger (P <.05) in the small bowel segments of animals treated with glycine. The responses evoked by 120 mmol/L of potassium were stronger in the distal segments of the small bowel in the glycine-treated group (P <.05). This cytoprotective effect of glycine was not dose-dependent. CONCLUSIONS: Glycine improved mucosal viability in the ischemia and reperfusion injury rat model. Mucosal thickness and villous circumference ratio were reliable objective parameters for evaluation of intestinal ischemia injury. Glycine improved the contractile responses of the bowel segments also, probably by altering the physiologic mechanisms underlying force generation. Further studies are required to elucidate the mechanism of the cytoprotective action of glycine.

Glycine prevents the induction of apoptosis attributed to mesenteric ischemia/reperfusion injury in a rat model.

PURPOSE: We have previously demonstrated that glycine has a protective effect in mesenteric ischemia/reperfusion (I/R) injury. The purpose of this study was to elucidate the molecular mechanisms of the cytoprotective action of glycine. Because oxidative stress in I/R injury can lead to apoptosis, we examined the role of glycine in modulating the apoptotic signals in a rat mesenteric I/R injury model. METHODS: Twenty-four anesthetized male Sprague-Dawley rats were subjected to 1 hour of mesenteric ischemia followed by 2 hours of reperfusion. Control animals (n=6) received normal saline intravenously at the rate of 0.01 mL/g/h during the ischemia and reperfusion period. Treated animals divided in 3 groups (n=6 in each) received glycine at a dose of either 0.5, 0.75, or 1.0 mg/g, infused at the rate of 0.01 mL/g/h during the reperfusion period. Animals were killed at the end of the experiment, and proximal, middle, and distal segments of the small bowel were harvested for histopathology, TUNEL assay, and immunohistochemistry. Expression of apoptosis-related molecules, bcl-2, bax, caspase-3, death receptor, Fas, and death substrate, poly (ADP-ribose) polymerase (PARP) were studied. RESULTS: In glycine-treated animals, the middle and distal segments of the small intestine were well- preserved and showed better histologic grade and morphometric parameters as compared with saline controls (P<.05) in a dose-independent manner. There was increased apoptosis in saline controls as compared to the treated group (P<.01). Pro-apoptotic bax and caspase-3 were downregulated, whereas bcl-2 was upregulated in the glycine-treated animals (P<.02). Increased expression of death receptors and cleavage of PARP was observed in saline controls as compared to treated groups (P<.05). No significant differences were noted between the proximal bowel segments of treated and control animals. CONCLUSIONS: These data support the concept that I/R causes formation of death- inducing signal complexes, which may activate the sequential cleavage of caspases and death substrates. We have demonstrated that one of the mechanisms of the protective effect of glycine is the downregulation of the death-inducing signals and abrogation of the apoptotic cascade in this I/R injury model.

Endovascular management of axillofemoral bypass graft stump syndrome.

OBJECTIVE: Upper extremity embolic complications of occluded axillofemoral bypass grafts are infrequent. However, traditional management of dissection of axillary anastomosis for removal of the stump can be challenging. We report two patients with critical upper extremity ischemia secondary to stump syndrome and its successful management with endovascular techniques. METHODS: One hundred fifty-two patients underwent axillofemoral bypass grafting over 10 years from 1991-2001. Two patients from this series had acute ischemia involving the ipsilateral upper extremity of occluded axillofemoral bypass graft. Duplex ultrasound scans revealed occlusion of the axillofemoral bypass graft and acute occlusion of ipsilateral upper extremity arteries. Both patients underwent brachial artery exploration and embolectomy. Completion angiograms revealed persistent axillofemoral bypass graft stump as the source of embolus. The stump was obliterated with a 10-mm/40-mm Wallgraft introduced through the same arteriotomy made for brachial embolectomy. Transesophageal echocardiography and magnetic resonance angiography of the arch and great vessels were performed to exclude other sources of origin for the embolus. RESULTS: Both patients remained symptom-free and with patent stent grafts, as seen on duplex scans at 3, 6, and 9 months of follow-up. CONCLUSIONS: Upper extremity embolism is a rare complication after occlusion of axillofemoral bypass grafts. The endovascular approach to obliterate the stump of occluded axillofemoral bypass grafts is minimally invasive and an effective alternative treatment of this rare condition.

Acute lower limb ischemia: the value of duplex ultrasound arterial mapping (DUAM) as the sole preoperative imaging technique.

Contrast arteriography (CA) is the gold standard preoperative imaging modality for patients with chronic and acute lower limb ischemia. We have previously shown that high-quality DUAM can safely replace CA in patients with chronic ischemia. The goal of this study was to investigate whether DUAM can also be used effectively in the setting of acute ischemia. From January 1998 to February 2001, 68 patients were admitted to our institution with 87 instances of acute lower limb(s) ischemia and underwent 87 operations. There were 34 men and 34 women whose age ranged from 51 to 95 years (mean 72 +/- 12.5). There were 44 cases of acute arterial occlusions and 43 cases of bypass graft thromboses. In the former group the most proximal occluded site based upon duplex was the aorta in 1 case, common iliac in 4 cases, external iliac in 15 cases, and infrainguinal arteries in 24 cases. In the latter group, there were 4 suprainguinal grafts, 24 bypasses to the popliteal artery, and 15 bypasses to infrapopliteal arteries. All patients had DUAM as their initial diagnostic study. The duplex protocol varied according to the pulse exam. In patients with a good femoral pulse but absent popliteal pulse, attempts were made to visualize the ipsilateral femoral-popliteal segment and the proximal third of the infrapopliteal arteries. This was extended to the pedal arteries in cases of proximal occlusion. When the femoral pulse was absent the protocol included visualization of the distal aorta, bilateral iliac, and common femoral arteries. This exam was extended into the deep and superficial femoral-popliteal segments in cases of proximal occlusion. None of these cases had preoperative or prebypass CA. Intraoperative arterial pressures to confirm the adequacy of the inflow tract and completion arteriography to assess the runoff were performed in 78% of the cases at the end of the procedure. This initial experience suggests that high-quality DUAM may replace CA in patients with lower limb ischemia. DUAM provides a reliable assessment of the inflow and outflow arteries even in very low-flow situations. In addition, DUAM can identify the cause of the arterial occlusion, thereby making therapy more effective and less time consuming.

Small popliteal artery aneurysms: are they clinically significant?

OBJECTIVE: We undertook this study to determine whether popliteal artery aneurysm diameter correlates with initial symptoms and presence of associated occlusive disease. METHODS: Duplex arteriography before infrainguinal revascularization in 500 lower extremities enabled diagnosis of 34 popliteal aneurysms in 25 patients (24 male, 1 female) over the last 4 years. Fourteen patients (41%) had no symptoms (group 1) and 20 (59%) had symptoms (group 2) of severe claudication (n = 8), acute ischemia (n = 6), rest pain (n = 2), and tissue loss (n = 4). We compared clinical presentation with popliteal artery diameter, prevalence of thrombosis, and presence of associated occlusive disease. RESULTS: Popliteal artery aneurysm diameter averaged 2.8 +/- 0.7 cm (range, 1.8-4.5 cm) in group 1 and 2.2 +/- 0.8 cm (range, 1.3-4.0 cm) in group 2 (P <.03). Popliteal aneurysm thrombosis was present in 7 of 20 limbs in group 2. Four of these patients also had ipsilateral superficial femoral artery thrombosis. Evaluation of the infrapopliteal arteries in group 1 showed three-vessel runoff in 7 limbs, two-vessel runoff in 3 limbs, one-vessel runoff in 2 limbs, and no vessel runoff in 2 limbs. However, all infrapopliteal arteries were either occluded or significantly stenotic in 14 limbs (70%). In group 2, one-vessel runoff was observed in 5 limbs, and two-vessel runoff in 1 limb. CONCLUSIONS: Smaller popliteal artery aneurysm was associated with higher incidence of thrombosis, clinical symptoms, and distal occlusive disease. Liberal use of duplex scanning in this setting may have accounted for the increased awareness that small popliteal artery aneurysms can thrombose and present with severe ischemia.

Cerebral hyperperfusion syndrome after carotid endarterectomy: predictive factors and hemodynamic changes.

PURPOSE: It is believed that cerebral hyperperfusion syndrome (CHS) is caused by loss of cerebral autoregulation resulting from chronic cerebral ischemia and that factors including increased intraoperative cerebral blood flow, ipsilateral or contralateral carotid disease, and postoperative hypertension may cause CHS. We describe our experience with CHS, which diverges from published reports. MATERIALS AND METHODS: From March 2000 to February 2002 we performed 455 carotid endarterectomy (CEA) procedures in 404 patients at our institution. CHS developed 1 to 8 days (mean, 3.2 +/- 2.5 days) postoperatively in 9 patients (2%), 6 women and 3 men, whose age ranged from 52 to 84 years (mean, 69 +/- 8 years). Indications for surgery in 8 patients without neurologic symptoms were ipsilateral internal carotid artery (ICA) stenoses ranging from 70% to 99% (mean, 80% +/- 7%); the remaining patient had an ipsilateral stroke, with good clinical recovery, 7 weeks before CEA. Only 1 patient had significant contralateral ICA stenosis (70%). However, 5 patients had undergone contralateral CEA within the previous 3 months. CHS symptoms were severe headache in 5 patients, seizures in 3 patients (1 stroke), and visual disturbance and ataxia in 1 patient. All 404 patients (455 cases) underwent intraoperative and early (2 weeks) postoperative carotid artery duplex scanning. The 9 patients with CHS also underwent carotid artery duplex scanning at the time of the neurologic event. RESULTS: Mean intraoperative ICA volume flow (MICAVF) in the 9 CHS cases was not significantly different from that in the other 446 cases (170 +/- 47 mL/min and 182 +/- 81 mL/min, respectively). However, mean ICA volume flow (481 +/- 106 mL/min) and peak systolic velocity (PSV) (108 +/- 33 cm/s) for the 9 CHS cases measured at onset of symptoms were higher than those for the remaining 446 cases (267 +/- 87 mL/min and 80 +/- 26 cm/s, respectively) (P <.01). Of the 9 patients with CHS, only 3 had systolic blood pressures more than 160 mm Hg at onset of symptoms. Severity of ipsilateral and contralateral ICA stenoses was not significantly different between the 9 CHS cases and the remaining 446 cases. CONCLUSIONS: These data do not corroborate the common belief that CHS occurs preferentially in patients with severe ipsilateral or contralateral carotid disease, increased intraoperative cerebral perfusion, or severe hypertension. Recently performed contralateral CEA (<3 months) appears to be predictive of CHS.

Preliminary results of the new 6F TrapEase inferior vena cava filter.

The TrapEase filter is a permanent, symmetric nitinol filter that can be deployed through a low-profile sheath. Although the TrapEase is enjoying an increasing market share of inferior vena cava (IVC) filters, there are still limited clinical follow-up data on its use. This study is a retrospective review of 189 consecutive infrarenal TrapEase filters placed at our institution. The study included 80 men and 109 women, with an average age of 73 years (24-102). The most common indication for filter placement was a contraindication to warfarin. In total, 13% of the patients were treated with warfarin. The filter was successfully deployed in all cases, via the right femoral vein in 57% of the patients, via the left femoral vein in 32%, and via the right internal jugular vein in 11%. Follow-up studies were performed as clinically indicated. During the investigation, there were three cases of IVC thrombosis (1.5%) and one case of retroperitoneal hemorrhage potentially caused by filter placement. Two of the thrombosis cases resulted in serious sequelae. This study also represents the first report of a symptomatic pulmonary embolism (PE) after TrapEase filter placement. While this investigation does demonstrate a low overall complication rate of this new device, it raises the concern of an increase in IVC thrombosis rate.