Intraoperative assessment of renal and visceral artery reconstruction: The role of duplex scanning and spectral analysis

Transit-Time Volume Flow Measurements in Autogenous Femorodistal Bypass Surgery for Intraoperative Quality Control

The aim of this study was to assess intraoperative transit-time volume flow measurements (VFMs) as a tool for intraoperative evaluation of lower extremity arterial bypass grafts and to predict their patency. We analyzed 273 consecutive patients who had an infrainguinal bypass procedure using the great saphenous vein from 1998 until 2008; 103 had an intraoperative VFM. All intraoperative revisions were recorded and analyzed. Patency and revision rates were compared between those receiving and those not receiving intraoperative VFM. Cox regression was used for analysis of predictors of patency. Primary patency at 1 and 2 years was 75 and 67%, respectively, in patients receiving intraoperative VFM versus 72 and 69% in those without VFM ( p = .79). In the VFM group, 12% had an immediate revision versus 6% without VFM ( p = .06). In the VFM group, 4% underwent revision to salvage the bypass within the first postoperative 30 days versus 6% without VFM ( p = .32). Patency was not associated with the use of VFM. Receiver operating characteristic curve was significant for occlusion at 30 days postoperatively but with a low predictive value ( p = .019,area under the curve 0.648). VFM may be helpful in selecting bypasses requiring immediate revision to prevent postoperative occlusion. The use of VFM is not significantly associated with patency.

Branch renal artery repair with cold perfusion protection

PURPOSE

This retrospective review describes the use and clinical outcome of cold perfusion protection during branch renal artery (RA) repair in 77 consecutive patients.

METHODS

From July 1987 through November 2006, 874 patients had open operative RA repair to 1312 kidneys. Seventy-seven patients (62 women, 15 men; mean age, 44 +/- 17 years) had branch RA reconstruction using ex vivo or in situ cold perfusion protection for 78 kidneys. Demographic data and surgical technique were examined. Blood pressure response and renal function were estimated. Patency of repair was determined by angiography and renal duplex ultrasound (RDUS) imaging. Primary RA patency was estimated by life-table methods.

RESULTS

Seventy-eight RAs were repaired using ex vivo (49 kidneys) or in situ (29 kidneys) cold perfusion protection. Bilateral RA repair was performed in eight patients, with 13 repairs to solitary kidneys. RA disease included aneurysm (RAA) in 50, fibromuscular dysplasia (FMD) in 37, atherosclerosis in 5, and arteritis in 2; 16 patients had both FMD and RAA. Hypertension was present in 93.5% (mean blood pressure, 184 +/- 35/107 +/- 19 mm Hg; mean of 1.9 +/- 1.1 drugs). RA repair included bypass using saphenous vein in 69, hypogastric artery in 3, polytetrafluoroethylene (PTFE) in 2, composite vein/PTFE in 2, cephalic vein in 1, or aneurysmorrhaphy in 1. The eight bilateral RA repairs were staged. One patient required bilateral cold perfusion protection. One planned nephrectomy was performed at the time of contralateral ex vivo reconstruction. No primary nephrectomies were required for intended reconstruction. Each RA reconstruction required branch dissection and reconstruction (mean of 2.8 +/- 1.6 branches were repaired). Mean cold ischemia time was 125 +/- 40 minutes. Each kidney was reconstructed in an orthotopic fashion. Five early failures of repair required three nephrectomies and one operative revision. Based on postoperative angiography or RDUS, or both, primary patency of RA repair at 12 months was 85% +/- 5%; assisted primary patency was 93% +/- 4%. Among patients with preoperative hypertension, 15% were cured, 65% were improved, and 20% were considered failed. Early renal function was improved in 35%, unchanged in 48%, and worse in 17%. Four patients had perioperative acute tubular necrosis. No patient progressed to dialysis-dependence.

CONCLUSION

Both ex vivo and in situ cold perfusion protection extend the safe renal ischemia time for complex branch RA repair and avoid the need for nephrectomy.

Intraoperative sonogram in mesenteric revascularization: spectrum of findings

OBJECTIVE

The role of intraoperative sonography is to detect and prompt revision of technical defects that may adversely affect results. Our objective is to describe the technique and illustrate normal and abnormal findings in intraoperative sonography of mesenteric revascularization.

CONCLUSION

An abnormality on a gray-scale image associated with hemodynamic changes is a significant finding. Awareness and recognition of major abnormalities should prompt immediate surgical revision and improved outcome.

Intraoperative duplex ultrasound of visceral revascularizations: optimizing technical success and outcome

PURPOSE

The purpose of this study was to evaluate the use of intraoperative duplex ultrasound scanning (IOUS) during visceral revascularizations and correlate its results with clinical outcome.

METHODS

We studied 68 patients (15 men and 53 women, mean age 66.5 years, range 27-86 years) who underwent visceral revascularization with concomitant IOUS examination of 120 visceral arteries (52 celiac, 60 superior mesenteric, and 8 inferior mesenteric arteries) from 1992 to 2002. Patients were divided into two groups on the basis of ultrasound findings: normal and abnormal IOUS. The incidence of early and late graft-related complications (thrombosis, restenosis, recurrent symptoms, reintervention) and graft-related death was compared in both groups.

RESULTS

One-hundred and two (85%) arteries had normal IOUS. Eight (6.6%) arteries had minor defects, including small kinks (4), mild residual stenoses (3), and small intimal flap (1). Ten (8.4%) arteries had major defects, consisting of hemodynamically significant residual stenoses (4), thrombus (2), kinks (2), bidirectional flow (1), and intimal flap (1). Major defects were successfully revised in all except three cases: two persistent mild stenoses and one bidirectional flow. Patients with abnormal IOUS at the end of the operation had increased incidence of graft-related complications and/or death (55.5% vs 7.8%; P =.004), early graft thrombosis (14.2% vs 1.0; P =.04), reintervention (21.4% vs 3.2%; P =.03), and graft-related death (33.3% vs 1.9%; P =.02), compared with patients with normal IOUS.

CONCLUSION

This study supports the routine use of IOUS during visceral revascularizations to optimize technical success and outcome. Persistent ultrasound scanning abnormalities are associated with risk of early graft failure, reintervention, and death. Patients with normal ultrasound scans can expect excellent results.

Guidelines for the Reporting of Renal Artery Revascularization in Clinical Trials

Although the treatment of atherosclerotic renal artery stenosis with use of percutaneous angioplasty, stent placement, and surgical revascularization has gained widespread use, there exist few prospective randomized controlled trials (RCTs) comparing these techniques to each other or against the standard of medical management alone. To facilitate this process as well as help answer many important questions regarding the appropriate application of renal revascularization, well-designed and rigorously conducted trials are needed. These trials must have clearly defined goals and must be sufficiently sized and performed so as to withstand intensive outcomes assessment. Toward this end, this document provides guidelines and definitions for the design, conduct, evaluation, and reporting of renal artery revascularization RCTs. In addition, areas of critically necessary renal artery revascularization investigation are identified. It is hoped that this information will be valuable to the investigator wishing to conduct research in this important area.

Guidelines for the reporting of renal artery revascularization in clinical trials

Although the treatment of atherosclerotic renal artery stenosis with use of percutaneous angioplasty, stent placement, and surgical revascularization has gained widespread use, there exist few prospective randomized controlled trials (RCTs) comparing these techniques to each other or against the standard of medical management alone. To facilitate this process as well as help answer many important questions regarding the appropriate application of renal revascularization, well-designed and rigorously conducted trials are needed. These trials must have clearly defined goals and must be sufficiently sized and performed so as to withstand intensive outcomes assessment. Toward this end, this document provides guidelines and definitions for the design, conduct, evaluation, and reporting of renal artery revascularization RCTs. In addition, areas of critically necessary renal artery revascularization investigation are identified. It is hoped that this information will be valuable to the investigator wishing to conduct research in this important area.

Chronic splanchnic ischaemia

Chronic splanchnic ischaemia is a relatively unusual clinical entity consisting of pain and/or weight loss and caused by chronic splanchnic disease (i.e. stenosis and/or occlusion of the coeliac and superior mesenteric artery). The occlusive disease is usually caused by atherosclerosis and is in itself not rare in older individuals. Extensive collateral circulation can develop between the three splanchnic arteries and may compensate for the decreased splanchnic perfusion over time. The pathophysiology of chronic splanchnic ischaemia has still not been completely elucidated.A reliable diagnosis of chronic splanchnic ischaemia, based on a proven causal relationship between the occlusive disease and the symptoms, can be very difficult. Traditionally, tests for evaluating the haemodynamic consequences of the vascular stenoses were not available. Important improvements in establishing a more reliable diagnosis have been achieved with duplex ultrasound and magnetic resonance evaluation of the splanchnic circulation. Tonometry is another promising functional test that may prove useful not only for gaining greater insight into the pathophysiology of chronic splanchnic ischaemia but also for the clinical evaluation of this syndrome. The natural history of chronic splanchnic disease suggests that progressive disease may result in acute mesenteric ischaemia. Surgical reconstruction of the coeliac and/or the superior mesenteric artery is the therapeutic standard with excellent short and long-term results. Satisfactory early results using angioplasty with or without stent suggest that this type of intervention may relieve symptoms in selected patients with a higher surgical risk.

Intraoperative renal duplex sonography: a valuable method for evaluating renal artery reconstructions

OBJECTIVES

to determine the ability of duplex sonography to intraoperatively detect technical problems with renal artery reconstructions.

DESIGN

retrospective evaluation of a standard protocol.

PATIENTS AND METHODS

the outcome of intraoperative duplex was compared with postoperative angiography, surface duplex, MRA, echo or direct inspection in case of re-exploration in 77 renal artery reconstructions in 62 patients. These included six extracorporeal reconstructions, eight and 17 reconstructions with an artery and autogenous vein respectively, 10 renal artery re-implantations in the aorta (prosthesis), 32 endarterectomies and four reconstructions of kidney transplant vessels.

RESULTS

intraoperative duplex was normal in 67/73 reconstructions with sufficient data. In six cases technical problems were revealed by intraoperative duplex and the reconstruction was re-explored. After re-exploration intraoperative duplex was normal in all cases. Confirmatory studies demonstrated normal results in 61/64 reconstructions with normal intraoperative duplex and abnormal results in 6/6 reconstructions with technical problems revealed by intraoperative duplex. Three reconstructions with normal intraoperative duplex occluded as demonstrated by angiography less than 2 weeks after surgery.

CONCLUSIONS

renal duplex sonography is a valuable method available for intraoperative detection of technical problems. Haemodynamic duplex data were less important than B-mode imaging in discriminating between normal and abnormal reconstruction.

Intraoperative duplex monitoring of infrainguinal vein bypass procedures

PURPOSE

The purpose of this study was to evaluate intraoperative duplex scanning of infrainguinal vein bypass grafts to detect technical and hemodynamic problems, monitor their repair, and correlate findings with the incidence of thrombosis and stenosis repair rates within 90 days of operation.

METHODS

Color duplex scanning was used at operation to assess vein/anastomotic patency and velocity spectra waveforms of 626 infrainguinal vein bypass grafts (in situ saphenous, 228 grafts; nonreversed translocated saphenous, 170 grafts; reversed saphenous, 147 grafts; alternative [arm, lesser saphenous], 81 grafts) to the popliteal (n = 267 grafts), infrageniculate (n = 323 grafts), or pedal artery (n = 36 grafts). The entire bypass graft was scanned after intragraft injection of papaverine hydrochloride (30-60 mg) to augment graft flow. Vein/anastomotic/artery segments with velocity spectra that indicate highly disturbed flow (peak systolic velocity, >180 cm/sec; spectral broadening; velocity ratio at site, >3) were revised. Grafts with a low peak systolic velocity less than 30 to 40 cm/s and high outflow resistance (absent diastolic flow) underwent procedures (distal arteriovenous fistula, sequential bypass grafting) to augment flow; if this was not possible, the grafts were treated with an antithrombotic regimen, including heparin, dextran, and antiplatelet therapy.

RESULTS

Duplex scanning prompted revision of 104 lesions in 96 (15%) bypass grafts, including 82 vein/anastomotic stenoses, 17 vein segments with platelet thrombus, and 5 low-flow grafts. Revision rate was highest (P <.01) for alternative vein bypass grafts (27%) compared with the other grafting methods (reversed vein bypass grafts, 10%; nonreversed translocated, 13%; in situ, 16%). A normal intraoperative scan on initial imaging (n = 464 scans) or after revision (n = 67 scans) was associated with a 30-day thrombosis rate of 0.2% and a revision rate of 0.8% for duplex-detected stenosis (peak systolic velocity, >300 cm/s; velocity ratio, >3.5). By comparison, 20 of 95 bypass grafts (21%) with a residual (n = 29 grafts) or unrepaired duplex stenosis (n = 53 grafts) or low flow (n = 13 grafts) had a corrective procedure for graft thrombosis (n = eight grafts) or stenosis (n = 12 grafts; P <.001). Overall, 8% of patients with bypass grafts underwent a corrective procedure within 90 days of operation. Secondary graft patency was 99.4% at 30 days and 98.8% at 90 days (eight graft failures).

CONCLUSION

The observed 15% intraoperative revision rate coupled with a low 90-day failure/revision rate (2.5%) for bypasses with normal papaverine-augmented duplex scans supports the routine use of this diagnostic modality to enhance the precision and early results of infrainguinal vein bypass procedures.

History of intraoperative ultrasound

Intraoperative ultrasound (IOUS) using A-mode or non-real-time B-mode imaging started in the 1960s; however, it was not widely accepted mainly because of difficulty in image interpretation. In the late 1970s, IOUS became one of the topics in the surgical communities upon the introduction of high-frequency real-time B-mode ultrasound. Special probes for operative use were developed. In the 1980s, all over the world the use of IOUS spread to a variety of surgical fields, such as hepatobiliary pancreatic surgery, neurosurgery, and cardiovascular surgery. IOUS changed hepatic surgery dramatically because IOUS was the only modality that was capable of delineating and examining the interior of the liver during surgery. After 1990, color Doppler imaging and laparoscopic ultrasound were incorporated into IOUS. Currently, IOUS is considered an indispensable operative procedure for intraoperative decision-making and guidance of surgical procedures. For better surgical practice, education of surgeons in the use of ultrasound is the most important issue.

David M. Hume memorial lecture. Surgical treatment of renovascular hypertension

BACKGROUND

Renal artery occlusive disease is the most common form of surgically correctable hypertension. Considerable scientific advances have improved our understanding of the pathophysiologic sequellae of a renal artery stenosis, the means of documenting the functional importance of such lesions, and the role of alternative surgical approaches in treating this disease. This work assesses the historical basis for the surgical treatment of renovascular hypertension.

DATA SOURCES

A review of the American literature on the subject of renovascular hypertension was undertaken, with particular attention to early work emanating from the University of California, San Francisco, the University of Michigan, and Vanderbilt University. These three institutions had considerable influence on the evolving techniques of operative intervention for renovascular hypertension.

CONCLUSIONS

The contemporary surgical management of renal artery stenotic disease causing secondary hypertension includes recognition of the heterogeneic character renal artery diseases, documentation of the functional significance of the stenoses, and performance of a properly chosen operation. Surgical therapy benefits 85% to 95% of properly selected patients having renovascular hypertension.

Transaortic mesenteric endarterectomy

Although a number of methods for mesenteric artery reconstruction have been suggested, we believe that patients with atherosclerotic stenosis and occlusion of mesenteric vessels presenting with either acute or chronic visceral ischemia are best managed by either antegrade aortomesenteric bypass or transaortic mesenteric endarterectomy. Antegrade bypass is the most versatile technique and is therefore best adapted to extensive mesenteric disease. Transaortic mesenteric endarterectomy lends itself well to simultaneous renal artery endarterectomy when clinically significant osteal atherosclerosis is present at both sites. With any method of reconstruction, the technical adequacy of repair should be defined intraoperatively. In this regard, intraoperative duplex sonography provides both anatomic and hemodynamic data necessary to ensure technical success and late patency.

Duplex sonography of lower extremity arteries

Although indirect noninvasive tests continue to play a role in the evaluation of patients with lower extremity arterial disease, the direct approach of duplex scanning provides both anatomic and physiological information directly from the involved arterial sites. Experience has shown that the results of duplex scanning are comparable with those of arteriography. The addition of color Doppler imaging to standard duplex scanning expedites the examination by helping to identify vessels and localize flow disturbances. However, precise classification of disease severity still requires spectral waveform analysis. Initial screening of patients with duplex scanning can determine the severity of arterial occlusive disease, the location of the lesions, and which interventional techniques are most appropriate. Arteriography can then be reserved for those patients who are being considered for therapeutic interventions. Duplex scanning has become the primary diagnostic test for follow-up of patients after radiological or surgical procedures and should be considered as an essential component of care for patients with infrainguinal bypass grafts. It has also proven to be valuable for intraoperative assessment and the initial evaluation of suspected vascular trauma in the extremities. Finally, new applications such as compression therapy for pseudoaneurysms continue to evolve and expand the role of duplex scanning in the management of patients with vascular problems.

Follow-up evaluation after renal artery bypass surgery with use of carbon dioxide arteriography and color-flow duplex scanning

PURPOSE

Postoperative evaluation of renal artery bypass grafts historically has been obtained by contrast renal arteriography before discharge from the hospital. Recent reports have advocated replacing arteriography with abdominal duplex scanning for evaluating and monitoring the integrity of renal artery bypasses. We propose a combination of these two techniques, which provides minimal risk to the patient and renal parenchymal function.

PURPOSE

Between July 1, 1990, and Dec. 31, 1991, 17 patients (8 men, 9 women) underwent 24 renal artery bypasses for poorly controlled hypertension or deteriorating renal function. In the immediate postoperative period each patient underwent carbon dioxide (CO2) renal arteriography to detect any technical defects and to define bypass graft anatomy. Subsequently, color-flow duplex scanning of the renal artery bypass grafts were done at 3-month intervals with the postoperative CO2 arteriogram for baseline comparison. CO2 arteriography clearly defined proximal/distal anastomotic anatomy, bypass conduit integrity, and bypass conduit runoff.

RESULTS

Procedural morbidity was zero because no hematomas developed and serum creatinine remained stable. Duplex scanning for a mean follow-up of 8.3 months revealed antegrade flow in 23 bypasses with peak systolic velocity of 60 to 100 cm/sec. One bypass graft had a peak systolic velocity greater than 150 cm/sec suggestive of a proximal anastomotic stenosis; however, the patient died before a repeat, verifying CO2 arteriogram could be obtained. Recurrent hypertension developed in one patient with velocities less than 100/cm/sec, and repeat CO2 arteriography revealed no evidence of graft or anastomotic stenosis.

CONCLUSION

CO2 arteriography and duplex scanning provide an accurate means of initially evaluating and subsequently monitoring renal artery bypass grafts, with minimal risk of renal or patient morbidity.

Acute mesenteric ischemia: pathophysiology, diagnosis, and treatment

Ischemia has traditionally been viewed as arising only from abnormalities of oxygen dynamics, namely the cellular hypoxia resulting from the imbalances between oxygen supply, consumption, and demand. Recently, it has become clear that such a view is too restrictive. Hypoperfusion may be caused by both anatomic and functional impediments to either inflow or to outflow from an organ. Furthermore, the pathophysiologic consequences are likely to involve not only cellular hypoxia, but also a restricted supply of nutrients and other important molecules and an abnormal elimination of physiologic wastes such as carbon dioxide. Hence the recommendation that ischemia be defined as a dual defect of oxygen deficit and carbon dioxide excess. AMI is, therefore, a severe anatomic or functional impediment to the splanchnic circulation, resulting in a dual defect of intestinal hypoxia and cellular hypercarbia. Although the functional and structural consequences of cellular hypoxia are well known, the pathophysiology of cellular hypercarbia has only begun to be explored. AMI syndromes include three related processes: occlusive mesenteric ischemia, nonocclusive ischemia, and sepsis-induced SI. Leakage of bacteria or bacterial toxins into the circulation during mesenteric ischemia forms the basis of the systemic components of this syndrome. Striving for an earlier diagnosis, treating the systemic (septic) consequences, and taking measures to promptly restore mucosal oxygen balance through aggressive pharmacologic and appropriate surgical intervention have significantly improved the prognosis. About 80% of patients with acute arterial embolism, 60% of those with nonocclusive ischemia, and only 20% of patients with arterial thrombosis are expected to live without significant residual nutritional deficits. The cause of death is usually sepsis and multisystem organ failure, and therefore, further reductions in mortality are likely to occur with the improved prevention and treatment of sepsis.

Intraoperative B-mode ultrasonography is a useful adjunct to peripheral arterial reconstruction

We used an ultrasound imaging system with a 10 MHz probe during 118 vascular procedures. These procedures included 56 cerebrovascular, 38 infrainguinal, 16 renal, 4 mesenteric, and 4 aortic reconstructions. In 29 procedures, intraoperative ultrasonography was used to supplement or replace preoperative arteriography to better define the extent of disease for the optimal placement of an anastomosis or to determine the need for an additional reconstructive procedure. In 106 cases, ultrasonography was used for postreconstruction assessment. Of the 21 (20%) defects found, 11 (10%) were deemed important enough to warrant correction. Defects were significantly more common following endarterectomy procedures (p < 0.01). All 11 of the major defects were successfully repaired, and neither the corrected defects nor the 10 uncorrected minor defects were associated with postoperative complications. Patients (with and without defects) underwent routine early postoperative follow-up assessment of the technical adequacy of their reconstruction using color duplex imaging; no residual defects were discovered. Two (2%) postoperative occlusions (one femorofemoral and one aortorenal bypass) occurred without a technical defect noted on reexploration. This clinical experience demonstrates that B-mode ultrasonography can supplement or replace preoperative arteriography in selected cases and is a valuable technique for identifying defects intraoperatively so that they can be immediately corrected.

Chronic visceral ischemia

Visceral ischemic syndromes constitute a spectrum of diseases that may, if not detected and treated, culminate in fatal intestinal gangrene. Symptomatic chronic visceral ischemia may run a prolonged course before diagnosis and effective surgical revascularization is employed. The internist or general practitioner plays an important role in the management of all patients with chronic visceral ischemia, usually being the first physician to evaluate the patient and often being able to direct the efforts to diagnose the problem effectively. An awareness of the disease and a high index of suspicion will lead to the confirmatory arteriogram, after which appropriate consultation will ensure that treatment which becomes readily apparent. The vascular surgeon who possesses the skill to execute transaortic extraction endarterectomy and antegrade aortovisceral bypass can realistically meet the therapeutic challenge of this disease, relieving the patients' symptoms and, more importantly, preventing fatal intestinal gangrene.

Duplex scanning for the intraoperative assessment of infrainguinal arterial reconstruction: a useful tool?

Duplex scan, arteriography, and graft flow rates were used intraoperatively to assess 56 infrainguinal arterial reconstructions for technical error. Intraoperative duplex scan identified a technical defect or low graft flow velocity in 22 of 56 (39%) grafts. Eleven of the defects were judged to be clinically significant and were corrected. Four of these defects were missed by the completion arteriogram. One technical defect identified by completion arteriography was missed by duplex scan. Fifty percent (5/10) of grafts with an abnormal intraoperative duplex scan which were not corrected occluded within 30 days. Graft flow rates measured by the electromagnetic flowmeter were neither predictive of technical defect nor early graft outcome. Although the sensitivity of arteriography and duplex scan (88% sensitivity for both) were both high for predicting early graft occlusion, the combination of duplex scan and completion arteriography was significantly more accurate (p less than .0001) in predicting early graft outcome than either study alone. Duplex scan identified significant graft defects which were not detected by completion arteriography or graft flow rate measurement. The duplex scan also provided hemodynamic information which was predictive of early graft outcome. The duplex scan can be an important adjunct to completion arteriography for the intraoperative assessment of infrainguinal arterial reconstruction.

Atherosclerotic occlusive disease of the superior mesenteric artery: late results of reconstructive surgery

Between 1975 and 1988, 103 patients underwent reconstruction of the superior mesenteric artery for atherosclerotic occlusive disease. Patients undergoing revascularization with associated mesenteric infarction were excluded. There were 89 men and 14 women whose mean age was 57.2 years. Six patients were operated on emergently for impending mesenteric infarction; six patients underwent revascularization after intestinal resection for ischemic lesions; 20 patients had typical abdominal angina; 39 patients had nonspecific abdominal symptoms, and 32 patients underwent revascularization of their superior mesenteric artery for asymptomatic lesions. Revascularization of the celiac axis and inferior mesenteric artery was associated in 36 and four cases, respectively. Four patients (4%) died postoperatively. Four early occlusions (4%) were observed. During the follow-up period (mean = 69 months), 18 patients died; five patients had recurrent intestinal ischemic symptoms, four of whom died. All surviving patients underwent follow-up duplex scanning, examination, and arterial or venous digitalized angiograms in selected cases. Nine patients (9%) had anatomical abnormalities: two stenoses and seven occlusions. Failure of revascularization of the superior mesenteric artery was observed in patients with severe initial intestinal ischemia. Late complications were not statistically significantly related to the different techniques of revascularization used.

Intraoperative use of ultrasound in arterial surgery

Technical perfection is the goal of any arterial reconstruction so as to avoid postoperative complications. Experimental and clinical studies have clearly shown that these operations are imperfect and that some form of intraoperative surveillance is required to decrease the incidence of correctable technical defects. Ultrasound technology is uniquely suited for this role. This article describes the distinct advantages of duplex ultrasound for the intraoperative monitoring of vascular reconstructions.

Current applications of duplex and color Doppler ultrasound imaging: abdomen

Duplex ultrasound studies and color Doppler imaging have substantially enhanced the diagnostic capabilities of abdominal ultrasonography. The status of the flow in the major abdominal vessels is routinely obtainable along with anatomic information about the organs that they supply. The current applications of duplex and color Doppler imaging in evaluating the hepatic vascular system, hepatic transplants, aorta, splanchnic arterial system, renal artery and vein, renal transplants, and penile arterial system are reviewed. The indications for and limitations of these examinations, as well as the potential future uses, are discussed.

Endoaortic calcific proliferation of the upper abdominal aorta

Endoaortic calcified proliferation, also known as coral reef atherosclerosis represents a rare form of atherosclerosis characterized by a gross appearance and location in the thoracic and celiac aorta. We report two new cases of calcified obstruction of the aorta. In the first case, clinical examination revealed hypertension, abdominal angina associated with abdominal bruit, and diminished femoral pulses. The second case was diagnosed postoperatively when intractable hypertension and renal failure ensued following reconstruction of an abdominal aortic aneurysm. Accurate evaluation of lesions was possible through Doppler sonography, CT scan, and aortography. Because of hypertension and visceral ischemia, surgical treatment was required. Hypertension and intestinal angina were completely relieved in the first case, while hypertension and renal failure improved greatly in the second.