Optimizing technical success of renal revascularization: The impact of intraoperative color-flow duplex ultrasonography

Extravascular Ultrasound (EVUS) to Assess the Results of Peripheral Endovascular Procedures

Contrast arteriography (CA) is considered the gold standard to evaluate any phase in peripheral arterial disease (PAD) interventions, from diagnostics to final results. Nevertheless, duplex ultrasonography (DUS) mostly used for the pre/postoperative phase and follow-up control, could be a potential intraoperative adjunctive imaging tool to assess the effects of endovascular revascularization in patients with iliac and femoropopliteal lesions. The PAD “duplex-assisted” protocol includes a preoperative DUS control followed by an intraoperative and a postoperative control. The most important parameters are pulsed doppler spectral analysis and waveform changes, which are impossible to detect with intravascular ultrasound (IVUS). By using a similar acronym, the intraoperative DUS has been previously described as extravascular ultrasound (EVUS). B-mode imaging, color flow, and peak systolic velocity (PSV) are considered. EVUS could be very useful to evaluate the effects of endovascular treatment, mainly in cases of unclear CAs, severe calcifications and/or dissections. In the context of the “leaving nothing behind” strategy, EVUS can drive the physician to evaluate the absence of flow-limiting dissections and decide which target lesion should be treated with antirestenotic therapy, further vessel preparation, or stenting. The EVUS protocol could be a safe and feasible option to improve the completion assessment of endovascular PAD treatment. A better ultrasound waveform is a sign of improved luminal gain and compliance, which is extremely important to finalize the results of new peripheral device technology, such as intravascular lithotripsy.

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.

Surgical Management of Renal Fibromuscular Dysplasia: Challenges in the Endovascular Era

Percutaneous transluminal renal angioplasty (PTRA) is the primary treatment for renal fibromuscular dysplasia (RFMD). Surgical revascularization is limited to patients who fail or are unsuitable for PTRA. All patients who were operated on with RFMD since the indications for renal PTRA were expanded in our institution were retrospectively reviewed. Outcome included patency, hypertension, and renal function. Twenty-six patients had reconstruction of 32 renal arteries between 1998 and 2004. The mean age was 47.1 +/- 14 years; the majority (81%) were female. Six patients had bilateral disease and three had a solitary kidney. Operations were done for hypertension in 25 patients, renal artery aneurysm in 8, and chronic dissection in 1, alone or in combination. Six patients had a failed PTRA and 20 were unsuitable for it. Aortorenal bypass was done most often (n = 28) and saphenous vein was the preferred conduit (n = 25). The distal anastomosis was to the main renal artery in 13 patients and to the branch arteries in 19. Ex vivo repair was needed in five patients. Five intraoperative revisions were done because of abnormalities on duplex scan. One patient died unexpectedly 42 days after operation from myocardial infarction. Extrarenal complications occurred in five patients. Median follow-up was 2.4 (range, 42 days to 6.3) years and was available in all but one patient (96%). Two bypasses occluded at 3 and 376 days, which resulted in loss of the kidneys. One graft stenosis was treated successfully with PTRA at 239 days. All failures occurred in men. One-year cumulative primary patency was 89 +/- 8% and was not adversely affected by prior PTRA or complex repair. Hypertension at 1 year was cured in 27% of the patients and improved in 60%. No patient developed acute or chronic renal failure. Surgical reconstruction for RFMD has excellent short-term patency. Failed PTRA or complex reconstructions did not adversely affect outcome.

Renal artery stenosis and a functioning hilar paraganglioma: a rare cause of renovascular hypertension--a case report

Surgically correctable causes of hypertension are uncommon. Simultaneous occurrence of 2 such causes in the same individual is extremely rare. The authors describe a 25-year-old woman with congenital erythrocytosis, renal artery stenosis, and a paraganglioma. The possible mechanisms of renal artery stenosis in the presence of a catecholamine-secreting tumor are discussed.

Intraoperative ultrasound

Intraoperative ultrasound (IOUS) can provide various diagnostic information that is otherwise not available, and can guide or assist various surgical procedures in real time. With refinement of equipment, IOUS is currently used in a wide variety of surgical operations,such as hepatobiliary, pancreatic, endocrine, cardiovascular,and neurologic surgery. Our overview of IOUS, including instrumentation,techniques, indications, advantages, disadvantages,and future perspective, is described in this article. Being safe, quick, accurate, and versatile intraoperatively, IOUS is a valuable technique that surgeons are recommended to master to improve intraoperative decision making and surgical procedures.

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.

Sonography in renovascular hypertension

OBJECTIVE

To familiarize practitioners with different sonographic manifestations of renal artery compromise and the sonographic techniques for renal artery imaging.

METHODS

Approximately 1500 examinations evaluating for renal artery disease are performed in our vascular laboratory every year. Most of the patients have the symptoms of hypertension (possibly related to renovascular etiology) and renal insufficiency. From our cumulative experience, the optimal scanning techniques are defined for each renal artery, for extrarenal versus intrarenal vascular evaluation, and for patients with different body habitus. We have also tabulated our technical success rate. Cases with sonographic evidence of renal artery compromise are identified. The validity, sensitivity, and specificity of different parameters are examined.

RESULTS

We achieve an approximately 75% to 80% success rate in obtaining technically adequate studies. We have not found the tardus-parvus waveform evaluation to be as valuable as direct interrogation of the renal artery.

CONCLUSIONS

Duplex/color Doppler sonography serves a vital role in the diagnosis of renal artery stenosis and occlusion; it has an excellent correlation with contrast-enhanced angiography. It is also used for intraoperative or postrevascularization surveillance to show evidence of recurring stenosis, thrombosis, and other complications.

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.

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.

Intraoperative evaluation of small-calibre arterial reconstructions

A new hammerhead-shaped, small probe for intraoperative duplex ultrasound was devised to evaluate small-calibre arterial reconstructions. This probe was used in two patients; one with terminal liver cirrhosis who had a left hepatic lobe that had been transplanted from her mother, and a second patient with limb-threatening ischaemia who had undergone arterial reconstructions. The technique was diagnostically useful and contributed to successful clinical outcomes.

Safety and efficacy of transaortic renal endarterectomy as an adjunct to aortic surgery

PURPOSE

A study was undertaken to assess the safety and efficacy of transaortic endarterectomy for orificial atherosclerotic renovascular disease (ASRD), particularly in conjunction with surgery for concomitant aortic disease.

METHODS

Forty-three consecutive patients with ASRD treated with transaortic orificial eversion endarterectomy were studied retrospectively to identify surgical indications, technical features, operative morbidity and mortality rates, and efficacy.

RESULTS

A total of 76 renal arteries underwent transaortic endarterectomy for hypertension (88% of patients) or serum creatinine of 1.5 mg/dl or greater (65% of patients), including two patients undergoing dialysis. Concomitant aortic surgery was performed in 39 patients for aneurysmal (n = 30) or occlusive (n = 9) disease. Two (2.6%) of 76 renal endarterectomies required intraoperative conversion to bypass because of poor flow, and three arteries (3.9%) were reimplanted or bypassed because of fragility of the renal orifice after endarterectomy. Thirty-day operative death occurred in two patients (4.7%), and major morbidity occurred in six (14.0%). Hypertension was cured or improved in 83% of patients with hypertension. Among patients with preoperative renal insufficiency, function was improved in 19%, with dialysis discontinued in one of two patients receiving dialysis, and function was worse in 23%, with one patient dependent on dialysis.

CONCLUSION

Transaortic renal endarterectomy is an acceptably safe and effective adjunctive technique in selected patients with combined aortic disease and ASRD.

Advanced renovascular hypertension and renal insufficiency: trends in medical comorbidity and surgical approach from 1970 to 1993

PURPOSE

The primary aims of this study were to delineate trends in medical comorbidity and surgical approach in patients with renal atherosclerosis and azotemia.

METHODS

We reviewed 1643 patients undergoing renovascular surgery between 1970 and 1993. We focused on those with the most advanced kidney disease (serum creatinine > 2 mg/dl) (n = 402). Attention was focused specifically on trends in sex, age, medical risk factors, surgical technique (bypass vs endarterectomy), and outcome including eventual need for long-term dialysis.

RESULTS

From 1970 to 1980, 652 patients underwent renovascular surgery, with 98 (15%) having a serum creatinine > 2 mg/dl. From 1980 to 1993, the percentage of patients with renal insufficiency increased to 31% (304 of 991) (p < 0.001). Gender distribution did not change, but median age rose from 63.5 years in the first decade to 68.0 in the past 13 years. A remarkable increase in all serious medical risk factors also occurred (first vs second decade). Another significant trend was a shift toward bilateral simultaneous transaortic endarterectomy (18% from 1980 to 1985 vs 53% from 1986 to 1993; p < 0.01), which simplified and achieved complete renal revascularization, especially in patients having multiple renal artery stenoses and those needing aortic grafting for occlusive or aneurysmal disease (56% from 1970 to 1980 vs 75% from 1980 to 1993). Patients at low risk (0 to 1 comorbid medical conditions) had a 30-day mortality rate of 5.6% compared with patients at high risk (2 to 3 comorbid conditions) (15.5%) (p = 0.016). The eventual need for long-term dialysis remained low (9%) for patients with a preoperative serum creatinine of 2 to 2.9 mg/dl compared with those with a serum creatinine greater than 3 mg/dl (35%, p < 0.01).

CONCLUSIONS

In the past 20 years, there has been a remarkable increase in the medical comorbidity and extent of aortic disease in patients undergoing surgical revascularization for advanced renovascular hypertension and renal insufficiency. However, the surgical approach can be simplified and expedited by bilateral transaortic endarterectomy, and the risk of late dialysis can be reduced significantly by operating before the serum creatinine exceeds 3 mg/dl.

Renal endarterectomy vs. bypass for combined aortic and renal reconstruction: is there a difference in clinical outcome?

Are there differences in the patient characteristics and clinical outcome for transaortic renal endarterectomy vs. bypass grafting when either technique is combined with infrarenal aortic replacement for occlusive or aneurysmal disease? Two common perceptions persist: (1) combined aortic and renal procedures have a high risk and (2) bypass is easier and safer than endarterectomy. To address these controversies we compared 52 consecutive patients undergoing concomitant aortic and renal reconstruction between 1987 and 1991: 26 with bypass and 26 with endarterectomy. Bypass patients were older (70 vs. 64 years, p = 0.001), had more extensive plaque extending into the distal renal artery and more severe baseline azotemia (creatinine = 2.6 vs 1.7 mg/dl, p = 0.01), more clinically evident coronary heart disease (89% vs. 56%, p = 0.001), and a greater need for nephrectomy of a small nonfunctional pressor kidney (23% vs. 0%) than endarterectomy patients. In contrast, endarterectomy patients more commonly required aortic replacement for occlusive disease than for an aortic aneurysm (endarterectomy: 65% vs. 35%; bypass: 19% vs 81%, p = 0.002) and tended to require more intraoperative technical revisions (12% vs. 4%) than bypass patients. Both groups, however, experienced no operative mortality, had similar cardiorespiratory morbidity, and achieved equal improvement in hypertension (69% vs. 65%). Bypass patients, who already had more severe preoperative azotemia than endarterectomy patients, showed less improvement in the creatinine level (Cr = 2.1 vs. 1.4 mg/dl, p = 0.01) and had greater need for late dialysis (30% vs. 4%, p = 0.01). Only one patient on dialysis had graft occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)