Outflow Vessels Research Articles

Risk Factors for Poor Collateral Development in Claudication

The objective of this retrospective, cross-sectional study was to determine risk factors for poor collateral development in patients with claudication. The authors listed all patients with calf claudication who had undergone angiography in this hospital between 1999 and 2001 and extracted those with superficial femoral artery (SFA) occlusion, a popliteal artery without major lesions, and at least 1 patent calf artery. Forty-five patients met the criteria, and concomitant disease and claudication characteristics, ankle/brachial index (ABI) and number of outflow vessels were recorded. Three blinded observers calculated the number of collaterals on the angiograms, and the collateral count was related to the other factors by use of regression analysis. The mean patient age was 69 years (SD 11), and 62% were women. Their walking distance was 90 m (77) and ABI 0.47 (0.15). Thirty-three percent had diabetes and 50% had duration of symptoms longer than 5 years. The mean number of collaterals bypassing the occlusion was 15.1 (SD 4.8). Univariate regression analysis indicated an association (p <0.08) between few collateral vessels and diabetes, short duration of symptoms, current smoking habits, and old age. In the multivariate analysis only diabetes and short duration of symptoms were related to having few collaterals. In patients with claudication and SFA occlusion, few collaterals from the deep femoral artery appear to be associated with having diabetes and a short duration of symptoms.

Palmar Arch Revascularization for Arterial Occlusion of the Distal Upper Extremity

During a period of nine years, 10 patients, ages 42 to 66 years (55 +/- 7, mean +/- SD) underwent upper extremity bypass for ischemic changes to the hand not responsive to conservative management. Patients were referred from the vascular department at the authors' institution. Preoperative angiograms were performed and attempts at angioplasty or intravenous attempts to dissolve clots were carried out (with tissue plasminogen activator-tPA) when appropriate. Patients with persistent upper extremity ischemia and an obvious occlusion with reconstitution in the hand were candidates for upper extremity bypass to the palmar arch. All patients had upper extremity bypasses performed with reverse saphenous vein grafts. The proximal anastomoses (end-to-side) were performed by either the vascular or plastic surgery team, while all distal anastomoses (end-to-side) were performed by plastic surgery team microscopic magnification to the deep or superficial palmar arch. Postoperative follow-up ranged from 3 months to 3 years. The bypass graft to the hand resulted in improved pain and resolution of tissue ischemia in all cases. Patients with preoperative ulcers were completely healed by 3 months. The results are in accordance with previous studies demonstrating that improved blood flow afforded by the procedure can improve the healing of recalcitrant ulcers and mitigate the symptoms of ischemic changes. In addition, end-to-side anastomosis to the palmar arch offers significant advantages, in that the continuity of the arch is maintained with all possible outflow vessels, and the problems associated with size discrepancy in the anastomosed vessels are eliminated.

Ablation of the secondary heart field leads to tetralogy of Fallot and pulmonary atresia

Recent studies in chick and mouse embryos have identified a previously unrecognized secondary heart field (SHF), located in the ventral midline splanchnic mesenchyme, which provides additional myocardial cells to the outflow tract as the heart tube lengthens during cardiac looping. In order to further delineate the contribution of this secondary myocardium to outflow development, we labeled the right SHF of Hamburger–Hamilton (HH) stage 14 chick embryos via microinjection of DiI/rhodamine and followed the fluorescently labeled cells over a 96-h time period. These experiments confirmed the movement of the SHF into the outflow and its spiraling migration distally, with the right side of the SHF contributing to the left side of the outflow. In contrast, when the right SHF was labeled at HH18, the fluorescence was limited to the caudal wall of the lengthening aortic sac. We then injected a combination of DiI and neutral red dye, and ablated the SHF in HH14 or 18 chick embryos. Embryos were allowed to develop until day 9, and harvested for assessment of outflow alignment. Of the embryos ablated at HH14, 76% demonstrated cardiac defects including overriding aorta and pulmonary atresia, while none of the sham-operated controls were affected. In addition, the more severely affected embryos demonstrated coronary artery anomalies. The embryos ablated at HH18 also manifested coronary artery anomalies but maintained normal outflow alignment. Therefore, the myocardium added to the outflow by the SHF at earlier stages is required for the elongation and appropriate alignment of the outflow tract. However, at later stages, the SHF contributes to the smooth muscle component of the outflow vessels above the pulmonary and aortic valves which is important for the development of the coronary artery stems. This work suggests a role for the SHF in a subset of congenital heart defects that have overriding aorta and coronary artery anomalies, such as tetralogy of Fallot and double outlet right ventricle.

A Direct Measurement of Serum Amylase Levels Produced by Lung Cancer

The production of amylase by lung cancer has been previously diagnosed pathologically or immunohistochemically, or it has been confirmed by a decrease in serum levels after resection. It is possible to directly probe the continuous production of amylase by collecting samples from the inflow and outflow vessels of lung cancer. We herein describe an intraoperative measurement in which the amylase level in the pulmonary lobar vein was 3 times greater than that in the superior vena cava which was 6 times greater than the normal range. The venous level of amylase returned to a normal range after resection.

Effect of Warfarin Anticoagulation on Below-Knee Polytetrafluoroethylene Graft Patency

When polytetrafluoroethylene (PTFE) must be used for below-knee bypass to achieve limb salvage, effective anticoagulation with warfarin may improve graft survival. We analyzed our practice of routinely using oral anticoagulation to improve graft patency rates for PTFE grafts to below-knee popliteal and crural vessels in limb salvage procedures. We reviewed our established vascular database from February 1999 through April 2003 to identify those patients who required below-knee and tibial artery bypass with PTFE for critical limb ischemia. All patients were initiated on warfarin anticoagulation postoperatively, with an international normalized ratio (INR) of 2.0-3.0 considered therapeutic. All patients were discharged in the therapeutic range. Life-table analysis and Kaplan-Meier estimates were used to compare primary patency rates with regard to INR and position of distal anastomosis. Cox proportional hazards analysis was performed to compare the patency rates for grafts with therapeutic versus subtherapeutic anticoagulation while correcting for variability in distal runoff. Between February 1999 and April 2003, 74 patients (mean age, 69.2 years; 58% men) had 77 below-knee PTFE bypasses. Indications for operation included rest pain (43), ischemic ulcer (27), and gangrene (7). Patients presenting with occluded grafts more often had a subtherapeutic INR. Patients with a subtherapeutic INR (< or = 1.9) had a median primary graft patency of 6.8 months and those with a therapeutic INR (> or = 2.0) had a median primary graft patency of 29.9 months (p = 0.0007). Analysis by Cox proportional hazards model demonstrated a significantly better graft patency rate in patients with a therapeutic INR regardless of outflow vessel. The patency rates of PTFE grafts to infrageniculate vessels may be improved by effective anticoagulation with warfarin. This improved patency rate may also result in improved limb salvage and further support the use of PTFE grafts for critical limb ischemia when autogenous vein is not available. Predictably, the best results are seen with an INR therapeutic range of 2.0 to 3.0.

Type II lumbar endoleaks: Hemodynamic differentiation by contrast-enhanced ultrasound scanning and influence on aneurysm enlargement after endovascular aneurysm repair

The objective of this study was to differentiate type II lumbar endoleaks on the basis of dynamic features identified by contrast-enhanced ultrasound scanning (CUS) and to evaluate the role of this differentiation in detecting abdominal aortic aneurysm (AAA) enlargement > or =1 mL/mo. Eighteen male patients (mean age, 71.8 years) with type II lumbar endoleak suspected at CUS underwent computed tomography angiography (CTA) and digital subtraction angiography (DSA). On CTA, AAA volumes and endoleak visualization and volume were assessed. At CUS, performed after a bolus of 1.5 to 2.4 mL of a second generation blood pool contrast agent, the following parameters were evaluated: presence of contrast material within the aneurysmal sac (endoleak), delay of endoleak detection (wash-in) and disappearance (washout) from the beginning of contrast injection, visualization of inflow and outflow vessels, and presence of cavity filling. Statistical analysis was performed regarding endoleak features at CUS, endoleak detection at CTA, and rate of AAA enlargement. DSA confirmed all the endoleaks. Mean +/- standard deviation wash-in and washout times were 121.9 +/- 132.6 and 337.2 +/- 193.7 seconds, respectively; a significant relation was observed between these two parameters (P < .01, analysis of variance). By Youden plots, endoleaks were classified as hyperdynamic when wash-in was <100 seconds (n = 10, 55.5%) and/or washout was <520 seconds (n = 13, 72.2%). A slower washout was associated with nonvisualized outflow (66.7%) and/or inflow arteries (66.7%) ( P < .05). Eight endoleaks (44.4%) were missed at CTA; it occurred in hypodynamic endoleaks, absence of detectable inflow or outflow vessels, and absence of cavity filling at CUS (P < .05). Overall mean AAA volume increase rate was 1.1 +/- 1.7 mL/mo. By multiple logistic regression model, the washout time > or = 520 seconds was the only independent predictor of AAA volume increase > or = 1 mL/mo (8 patients, 44.4%). Type II lumbar endoleaks show different hemodynamic features at CUS, which might influence the rate of aneurysm enlargement, addressing the need for treatment.

Infrainguinal vein bypass graft revision: Factors affecting long-term outcome

We sought to determine the long-term results of revision procedures performed for repair of stenotic lesions in infrainguinal vein bypass grafts. A retrospective review of 188 vein grafts, from a total series of 1260 bypasses, undergoing revision of stenotic lesions between January 1, 1987, and December 31, 2002, at Brigham & Women's Hospital was undertaken. Lesions were identified by recurrence of symptoms, change in examination findings, or with routine duplex ultrasound graft surveillance. Demographic and medical risk factors, and surgical variables were analyzed with respect to patency outcomes after the initial graft revision, with descriptive statistics, logistic regression, and life table analysis. Primary and secondary patency rates were determined from the time of graft revision. Patients included 108 men (57%) and 80 women (42%) who underwent revision at a mean age of 67.8 years. One hundred thirty grafts required only a single revision, whereas 58 required subsequent additional revisions. Revision procedures included 99 vein patches (52.7%), 23 jump grafts (12.2%), 23 interposition grafts (12.2%), 8 transpositions to new outflow vessels (4.3%), and 35 balloon angioplasty procedures (18.6%). During a mean follow-up of 1535 days, 5-year primary patency rate was 49.3% +/- 4.5% (SE) and 5-year secondary patency rate was 80.3% +/- 3.6%. There was no difference in patency rate for different revision procedures, type of vein graft, indication for the original procedure, or for patients with diabetes mellitus or renal disease. The overall limb salvage rate was 83.2% +/- 3.5% 5 years after graft revision. With COX proportional hazard analysis of time to failure of the revision procedure, the outflow level of the original bypass and the time of revision proved to be an important predictor of durability of the graft revision. Revision of popliteal bypass grafts resulted in a 60% 5-year primary patency rate, whereas revision of tibial grafts resulted in a 42% 5-year primary patency rate (P = .004; hazard ratio [HR], 2.06). Five-year secondary patency rates were 90% and 76%, respectively (P = .009; HR = 3.43). The timing of the graft revision proved an additional predictor. Grafts revised within 6 months of the index operation had lower primary patency than those with later revisions (42.9% vs 80.7%, respectively; HR = 1.754; P = .0152). Vein graft revisions offer durable patency and limb salvage rates after repair of stenotic infrainguinal bypass grafts. Vigilant ongoing surveillance is essential, because 30.9% of revised grafts will develop additional lesions that will require repair. Tibial level bypass grafts that require early repeat intervention to treat graft stenosis are at particular risk for development of subsequent lesions.

Efficacy of Dextran Solutions in Vascular Surgery

The purpose of this paper is to discuss the role and efficacy of dextran in vascular procedures using evidence-based data from the review of surgical literature. A medline search using "dextran,'' "vascular surgery,'' and "antiplatelet therapy'' as keywords was performed for English-language articles. Further references were obtained through cross-referencing the bibliography cited in each work. Dextran is commonly used in carotid endarterectomy (CEA) patients where the embolic rate is reduced by 46%, resulting in fewer procedure-related strokes. As a prophylactic agent against thrombosis, multiple randomized studies have reported its benefit over other antithrombotic medications. Dextran is also particularly useful in "difficult'' infragenicular lower extremity bypasses where artificial grafts (such as polytetrafluoroethylene [PTFE] or umbilical vein) are used in the setting of poor outflow vessels, or those with composite grafts and small-caliber venous conduits. Distal bypasses with adjunctive procedures (eg, arteriovenous fistula or anastomotic cuffs) also have a better outcome with the addition of dextran. Dextran has numerous important implications in vascular surgery, in particular with CEA patients or "difficult'' infragenicular bypasses. Its effectiveness with endovascular stents remains unknown.

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.

Cystic adventitial disease of the popliteal artery

A 40-year-old Special Forces soldier with severe progressive right leg claudication underwent gadolinium-enhanced magnetic resonance angiography (MRA) (Cover), which demonstrated segmental occlusion of the popliteal artery. Further examination of the MRA revealed the occlusion to be caused by multiple cystic structures within the outer layers of the popliteal artery consistent with cystic adventitial disease (A). Standard contrast arteriography (B) confirmed the diagnosis. A posterior approach to the popliteal fossa was performed and revealed a 4-cm sausage-shaped segment of popliteal artery with near occlusion of the vessel (C). Resection of the affected arterial segment and placement of a greater saphenous vein interposition graft resulted in restoration of normal leg perfusion. A low-power photomicrograph of the arterial specimen depicted a multiloculated, subadventitial cyst. The patient was released after a brief hospitalization and one year later is symptom-free and maintains a normal pulse exam with normal noninvasive arterial studies. Atkins and Key1Atkins H.J.B Key I.A A case of myxomatous tumor arising in the adventitia of the left external iliac artery.Br J Surg. 1947; 34: 426-427Crossref PubMed Scopus (164) Google Scholar offered an early description of cystic adventitial disease in 1947 in a case that affected an iliac artery. One decade later Heirtonn, Lindberg, and Rob used the term “cystic adventitial degeneration of the popliteal artery” to depict the same process in a series of patients with popliteal artery involvement. Cystic advenitial disease of the popliteal artery is an unusual but important cause of peripheral vascular insufficiency in young men. Traditionally, the diagnosis of this condition has required contrast arteriography, which demonstrates an eccentric “sword-like” stenosis, described as a Scimitar sign. However, as demonstrated here, and as advocated by others, gadolinium-enhanced MRA is useful and may eliminate the need for invasive testing.2Miller A Salenius J.P Sacks B.A Gupta S.K Shoukimas G.M Noninvasive vascular imaging in the diagnosis and treatment of adventitial cystic disease of the popliteal artery.J Vasc Surg. 1997; 23: 715-720Abstract Full Text Full Text PDF Scopus (40) Google Scholar Gadolinium-enhanced MRA demonstrates detailed anatomy of the cysts in relation to the arterial lumen and surrounding structures while providing images of the affected arterial segment as well as inflow and outflow vessels.2Miller A Salenius J.P Sacks B.A Gupta S.K Shoukimas G.M Noninvasive vascular imaging in the diagnosis and treatment of adventitial cystic disease of the popliteal artery.J Vasc Surg. 1997; 23: 715-720Abstract Full Text Full Text PDF Scopus (40) Google Scholar Management of cystic adventitial disease may include removal of the cyst content (enucleation) without resection of the artery or resection of the affected segment with interposition grafting. In advanced cases with arterial occlusion or thrombosis venous interposition, grafting is an optimal strategy for the treat ment of this disease.

Popliteal artery aneurysms: a comparison of outcomes in elective versus emergent repair

Objective The purpose of this study was to assess and compare outcomes of elective versus emergent operative repair of popliteal artery aneurysms. Design A retrospective analysis of a prospectively recorded vascular surgery database from June 1992 to December 2002 was performed with chart review. Main outcome measures Patient survival, limb salvage, and graft patency were evaluated. Results Fifty-one popliteal artery aneurysms were repaired in 39 patients, all male and ranging in age from 18 to 87 years (mean 67.1). Mean follow-up was 47.8 months. Repair was elective in 37 (72.5%) and emergent in 14 (27.5%) limbs, 13 with acute ischemia and one with aneurysm rupture. Thrombolytic therapy was utilized in four ischemic limbs with no suitable bypass target vessel identified on initial arteriogram. Outflow vessels included the popliteal artery in 22 (43.1%) and infrapopliteal vessels in 29 (56.9%) limbs. Cardiac morbidity and 30-day mortality rates were 0%. Overall primary patency, secondary patency, limb salvage, and actuarial survival were 95.6%, 100%, 98.0%, and 98.0% at 1 year and 85.1%, 96.9%, 98.0%, and 83.8% at 5 years, respectively. Bypass graft redo or revision was performed for stenosis in one and occlusion in four limbs. Two amputations were performed at 6 days and 63.6 months after initial aneurysm repair. No difference was noted between elective and emergent groups with regard to patency, limb salvage, or survival ( P > .26), and no association between the number of identified target vessels and limb salvage or patency was demonstrated ( P = .12). Conclusion In our experience, the outcome of the popliteal artery aneurysm repair was comparable in the emergent and elective settings. Aggressive tibial reconstruction plays a crucial role in the treatment of popliteal artery aneurysms, especially in those presenting with acute limb ischemia. Thrombolytic therapy is infrequently required in the acute setting, although it may be useful in patients with no identifiable outflow target vessel on initial arteriogram.

Patency and limb salvage rates after distal revascularization to unclampable calcified outflow arteries

Purpose Severe circumferential calcification of the outflow artery during lower-extremity distal revascularization is considered a poor prognostic factor for bypass graft patency. The aim of this study was to assess the influence of circumferential infrapopliteal arterial calcification on bypass graft patency and limb salvage rates, comparing patency and limb salvage rates in unclampable calcified distal outflow arteries with those observed in uncalcified distal outflow arteries. Methods From July 1990 to July 1997, of 441 distal bypass graft procedures performed by the same surgeon, 69 (16%, group I) involved unclampable calcified outflow vessels, whereas 83 (19%, group II) outflow vessels were uncalcified; the other 289 (65%) had varying intermediate degrees of calcification and were not included in this analysis. All procedures were performed for limb-threatening ischemia and involved standard vein patch angioplasty of the distal anastomotic site, irrespective of the conduit used. Primary and secondary patency, limb salvage, and survival rates were assessed by using Kaplan-Meier analysis. Results Groups were similar with regard to age, sex, and atherosclerotic risk factors except for a higher incidence of diabetes mellitus (88% vs 65%, P = .001) and renal failure (17% vs 5%, P = .01), including dialysis dependency ( P = .01) in group I. Gangrene as an indication for surgery was statistically more frequent in group I (49% vs 29%, P = .01). The distal anastomotic locations and types of conduit involved were similar in the two groups. The femoral inflow level was used more often in group II (63% vs 38%, P = .003), the popliteal in group I (32% vs 17%, P = .03). Follow-up ranged from 30 days to 144 months, with a mean of 69 months. None of the patients were lost during the follow-up period. None of the patients died during the perioperative (30-day) period. Primary patency rates at 1, 3, and 5 years were 84%, 65%, and 52% for group I and 89%, 76%, and 69% for group II ( P = .07.). Secondary patency rates at 1, 3, and 5 years were 96%, 82%, and 78% for group I and 96%, 85%, and 82% for group II ( P = .58). Limb salvage rates at 1, 3, and 5 years were 93%, 83%, and 81% for group I and 97%, 90%, and 86% for group II ( P = .39). Conclusions Distal revascularization to unclampable, severely calcified outflow arteries can achieve much the same results to those obtained in uncalcified outflow arteries. A circumferentially calcified distal recipient artery should not be considered a major obstacle to an attempt at limb salvage bypass graft surgery.

N-Butyl Cyanoacrylate Glue Embolization of Splenic Artery Aneurysms

A patient with Polyarteritis Nodosa presented with abdominal pain and low hematocrit level. Abdominal computed tomography (CT) depicted the presence of free blood and CT angiography revealed two aneurysms in the inferior branch of the splenic artery that were subsequently treated by endovascular transarterial embolization with N-Butyl Cyanoacrylate. Post embolization splenic arteriography demonstrated complete embolization of both aneurysms, including the inflow and outflow vessels.

The role of altered impedance in the pathophysiology of normal pressure hydrocephalus, Alzheimer's disease and syringomyelia

Normal pressure hydrocephalus, Alzheimer's disease and syringomyelia appear to be completely unrelated diseases, however, they share a reduction in subarachnoid space compliance as part of their pathophysiology. This paper discusses the physiology of pulsatile fluid flow and its relationship to compliance/impedance. Unlike continuous or non-pulsatile flow where the vessel resistance and pressure gradient are the major determinants of the volume of fluid flowing, when the fluid flow in a vessel pulsates then the vessel compliance/impedance becomes important. A reduction in compliance in the craniospinal cavity in each of the three diseases discussed, leads to a limitation of the outflow vessel compliance. Therefore, there is an increase in outflow vessel impedance. The venous blood, CSF and interstitial brain/spinal cord fluid all have significantly pulsatile flow and an increase in the impedance of the fluid outflow in each disease would limit the volume of these fluids as they attempt to cross the subarachnoid space. It is hypothesised that a reduction in the efficiency of the outflow of venous blood, CSF and interstitial brain/spinal cord fluid would lead to the accumulation of CSF in NPH, cord fluid in syringomyelia and delay the excretion of beta amyloid via the interstitial drainage pathways in AD.

Endovascular techniques in the treatment of acute limb ischemia: thrombolytic agents, trials, and percutaneous mechanical thrombectomy techniques

Acute peripheral arterial occlusion is associated with great risk to the patient’s limb and life. Failure to restore adequate arterial flow in a timely fashion can result in the development of irreversible tissue infarction and the opportunity for limb salvage is lost. On the other hand, patients with acute limb ischemia are often elderly and frail, and early invasive open surgical procedures without adequate preoperative stabilization and preparation result in an unacceptably high risk of perioperative cardiopulmonary complications and death. Percutaneous methods designed to remove the intraluminal thrombus offer an alternative to immediate open surgical revascularization. These less invasive techniques constitute an option that is better tolerated in medically compromised patients. The causative lesion can be precisely identified and the patency of outflow vessels can be restored. The lesion can then be addressed on an elective basis in a well-prepared patient, using percutaneous or open surgical techniques to effect a durable long-term solution. The treatment options include primary surgical revascularization, thrombolytic therapy, percutaneous mechanical thrombectomy, or a combination of any of the three. Clinicians who themselves have the skills to perform a wide assortment of interventions ranging from percutaneous therapies through open surgical revascularization are best able to arrive at the most rational option for treating a specific clinical scenario. This article is directed at providing the practicing surgeon with a basic fund of knowledge on the diagnostic and therapeutic strategies useful in treating patients with peripheral arterial occlusion. Only in this manner can we expect to reduce the high rate of morbidity and mortality that remains associated with these events.

Alternative venous outflow vessels in microvascular breast reconstruction.

The lack of adequate recipient vessels often complicates microvascular breast reconstruction in patients who have previously undergone mastectomy and irradiation. In addition, significant size mismatch, particularly in the outflow veins, is an important contributor to vessel thrombosis and flap failure. The purpose of this study was to review the authors' experience with alternative venous outflow vessels for microvascular breast reconstruction. In a retrospective analysis of 1278 microvascular breast reconstructions performed over a 10-year period, the authors identified all patients in whom the external jugular or cephalic veins were used as the outflow vessels. Patient demographics, flap choice, the reasons for the use of alternative venous drainage vessels, and the incidence of microsurgical complications were analyzed. The external jugular was used in 23 flaps performed in procedures with 22 patients. The superior gluteal and transverse rectus abdominis musculocutaneous (TRAM) flaps were used in the majority of the cases in which the external jugular vein was used (72 percent gluteal, 20 percent TRAM flap). The need for alternative venous outflow vessels was usually due to a significant vessel size mismatch between the superior gluteal and internal mammary veins (74 percent). For three of the external jugular vein flaps (13 percent), the vein was used for salvage after the primary draining vein thrombosed, and two of three flaps in these cases were eventually salvaged. In three patients, the external jugular vein thrombosed, resulting in two flap losses, while the third was salvaged using the cephalic vein. A total of two flaps were lost in the external jugular vein group. The cephalic vein was used in 11 flaps (TRAM, 64.3 percent; superior gluteal, 35.7 percent) performed in 11 patients. In five patients (54.5 percent), the cephalic vein was used to salvage a flap after the primary draining vein thrombosed; the procedure was successful in four cases. In three patients, the cephalic vein thrombosed, resulting in two flap losses. One patient suffered a thrombosis after the cephalic vein was used to salvage a flap in which the external jugular vein was initially used, leading to flap loss, while a second patient experienced cephalic vein thrombosis on postoperative day 7 while carrying a heavy package. There was only one minor complication attributable to the harvest of the external jugular or cephalic vein (small neck hematoma that was aspirated), and the resultant scars were excellent. The external jugular and cephalic veins are important ancillary veins available for microvascular breast reconstruction. The dissection of these vessels is straightforward, and their use is well tolerated and highly successful.

Rat epigastric flow-through flap as a modulated arteriovenous fistula: model for the radial artery flow-through flap in distal arterial bypass.

The authors describe a rat flap model that is useful for flow studies. It is an epigastric flow-through flap that mimics the clinical use of a radial artery flow-through (RAFT) flap that has been used as an adjunct to a distal lower extremity arterial bypass graft to improve patency when there is potential high outflow resistance. The hypotheses were that this RAFT flap serves two purposes: 1) it allows additional blood flow through the skin flap and drainage via the vena comitans to increase the blood flow through the bypass graft and help to maintain bypass graft patency; and 2) it acts as a modulating arteriovenous fistula in which the additional flow through the vena comitans of the flow-through flap fluctuates with distal arterial outflow resistance. The rat epigastric flow-through flap model was designed to test these hypotheses. High outflow resistance was induced by sequentially ligating the outflow vessels of the rat femoral artery. Using this model, an increase in blood flow to the skin via the epigastric artery of the flow-through flap was demonstrated as outflow obstruction increased. Then, the patency rates of the flow-through flap bypass were compared to an interpositional arterial graft. The flow-through flap maintained patency while the arterial interposition bypass thrombosed, with near total outflow obstruction induced by serial ligation of the outflow vessels (75 percent patent anastomoses at 1 week for flow-through flap vs. 0 percent for the arterial graft). This flow study demonstrates the inherent ability of the flow-through flap to divert blood flow through the skin capillaries when there is high arterial outflow resistance. The authors believe that a flow-through flap such as the RAFT flap can be an important adjunct to the traditional distal arterial bypass in a subset of patients with high outflow resistance in the recipient artery.

Pedal Artery Imaging – A Comparison of Selective Digital Subtraction Angiography, Contrast Enhanced Magnetic Resonance Angiography and Duplex Ultrasound

Objective: to evaluate selective digital subtraction angiography (DSA), contrast-enhanced magnetic resonance angiography (CE-MRA) and duplex ultrasound (duplex) in preoperative pedal artery imaging.Material and Methods: DSA, CE-MRA and duplex were studied prospectively in 37 patients suffering from critical leg ischaemia. Two radiologists independently reviewed both the CE-MRA and DSA images. The pedal vessels were scored on a scale from 0 to III (0=vessel not visualised, I=vessel faintly visualised, II=stenosis >50%, III=vessel without relevant stenosis). Duplex ultrasound was performed by an angiologist blind to both the DSA and MRA findings and the pedal arteries were scored 0–III according to their diameter.Each examiner named the pedal artery best suitable for bypass surgery. Agreement in artery assessment was expressed as kappa values.Patency of the bypass at 30 days was used as validation of the artery's suitability as the run-off vessel.Results: interobserver agreement for DSA (weighted Kappa 0.63, CI 0.53–0.73 and CE-MRA (weighted kappa 0.60, CI 0.5–0.7) was moderate to substantial. CE-MRA depicted significantly more vascular segments than DSA (p≅0.0001).In the prediction of the distal outflow vessel duplex and CE-MRA proved to be superior to DSA.Conclusion: because of the moderate inter-observer agreement it may be questionable to regard selective DSA as gold standard imaging procedure in preoperative pedal artery imaging. CE-MRA and duplex are very helpful in assessing the pedal artery morphology and should be used if selective DSA does not sufficiently depict the pedal vasculature.

Expression of endothelins in human cardiogenesis.

Genetic disruption of endothelin (ET) 1, endothelin-converting enzyme (ECE) 1, and endothelin receptor A (ET(A)) in "knockout" or mutant mouse models result in defects in branchial arch derived craniofacial tissues and in cardiac outflow and great vessel structures. Interestingly, certain types of human congenital cardiovascular malformations such as Catch 22 syndrome and type B interruption of the aortic arch strongly resemble defects seen in knockout animal models. To better address the exact involvement of the ET system in heart formation we explored the spatiotemporal pattern of expression of the components of the ET system during critical phases of cardiogenesis in the human embryo (3-6 weeks of development; Carnegie stages 10-17) by in situ hybridization. We detected high ET-1 mRNA expression in endocardial cells lining the heart outflow tract in the region where the future aortic valves will form. No hybridization signal corresponding to pre-pro-ET-3 was observed in the heart. At the same location, the underlying myocytes express ET(A) mRNA. Whereas a functional role of ET in the valve formation can be proposed because of the simultaneous presence of all the components of the endothelin system (ET-1/ECE-1/ET(A)), this seems not to be the case for the formation of the ventricular septum where endocardial cells do not express ET-1, and only a weak ET(A) hybridization signal was detected in the surrounding myocardium. An abnormal hemodynamism indirectly due to valve malformation may be the indirect cause of this septal defect. The results of this study suggest an important role for the ET system in the formation of certain anatomical structures of the developing human heart.

Mechanism of failure in the treatment of type II endoleak with percutaneous coil embolization

Purpose: Type II endoleak after endovascular abdominal aortic aneurysm repair is a failure of aneurysm sac exclusion with unknown long-term consequences. Elevated aneurysm sac pressures documented in these patients have led us to aggressively treat type II endoleaks with percutaneous transluminal coil embolization (PTCE). The purpose of this study was to evaluate the results and the mechanisms of failure of PTCE for type II endoleak. Methods: One hundred ninety-one patients underwent endograft repair of infrarenal aortic aneurysms. Twenty-three of 28 patients with persistent primary (>3 months) or secondary (new-onset) endoleak underwent angiography; 14 of these patients had type II endoleaks. We reviewed our endovascular registry data, hospital charts, and radiologic studies of patients with type II endoleaks and analyzed the results in those treated with PTCE of the inflow vessel. Results: All 14 patients with type II endoleaks were men, with a mean age of 76.7 years and a mean preoperative maximal aneurysm diameter of 5.7 ± 1.0 cm. The type II endoleak was primary in 12 patients (86%) and secondary in two patients (14%) and iliolumbar in 11 patients (78%) and mesenteric in three patients (21%). Although a dominant affluent collateral channel (inosculation) was apparent in eight patients (57%), six patients (43%) showed a network of collateral vessels (retiform anastomosis). In six patients (43%), angiography revealed a second or “outflow” vessel indicative of a complex endoleak. In four patients with retiform iliolumbar type II endoleaks, PTCE was not attempted because of the retiform nature of the endoleak. The remaining 10 patients underwent PTCE, with coil deployment in all 10 and apparent initial technical success in nine patients. Follow-up computed tomographic scans revealed persistent endoleaks in six patients (60%). Mechanisms of failure included persistent flow through the coils in the treated vessel in two patients, development of a retiform anastomosis around the coiled vessel in three patients, and development of a new mesenteric endoleak after successful occlusion of an iliolumbar endoleak in one patient. Two patients underwent repeat PTCE with successful aneurysm sac exclusion in one. Internal iliac artery injury complicated one of the 12 PTCEs, and the resulting pseudoaneurysm was successfully treated with PTCE. Angiographic visualization of an outflow vessel (complex endoleak) was associated with PTCE failure ( P = .008). Conclusion: PTCE of type II endoleaks has a high failure rate because of multiple anatomic mechanisms. (J Vasc Surg 2002;36:485-91.)