Interventional radiology in the treatment of renal artery stenosis

Percutaneous transluminal renal angioplasty (PTRA) alone or in combination with stent implantation, is increasingly used as an alternative technique to surgical revascularization for treatment of renal artery stenosis (RAS) wich may cause hypertension or jeopardize renal function. Herein we report the results obtained with 305 PTRAs performed in 242 hypertensive patients, 144 of whom had atherosclerotic RAS, 69 fibromuscolar dysplasia, 15 Ras in transplanted kidneys, 6 restenosis in surgically revascularized kidneys, 4 Takayasu arteritis and 4 neurofibromatosis. Stents were implanted in 68 cases, mostly in atherosclerotic stenoses. The technical success was achieved in 261 arteries (85.6%), with 33 failures (10.8%) and 11 (3.6%) procedures not completed for anatomical reasons. PTRA related complications were observed in 23 cases (7.5%), but no fatalities occurred. An overall benefit on blood pressure control was observed in 41% of patients with atherosclerotic RAS and in 68% of those with fibromuscolar dysplasia. It appears that independently from the ethiology PTRA is technically effective in correcting RAS; yet the position of PTRA with respect to that of medical or surgical treatment needs to be better delineated through randomized, controlled studies aimed at comparing the clinical efficacies of these different approaches.

Interventional radiology in the treatment of urological vascular complications

Urological vascular complications (UVC) are largely secondary to percutaneous procedures that are nowadays extensevely used by the urologists and the nephrologists. The major frequency of UVC is observed after the renal biopsy, in a percentage varying from 7 to 17% in different series; UVC are less frequent after a nephrostomic procedure (near 1-3%). UVC consist of artero-venous fistulas (AVF) and pseudoaneurysms (PA), that generally cause haemorrhage, particularly macroscopic hematuria. In the vast majority of cases hematuria resolves spontaneously or with conservative therapy but, in the 4 to 9% of patients persists and requires an adequate therapy, often in emergency. Interventional radiology permits an effective and timely treatment of the lesions, using the techniques of transcatheter embolization that are greatly improved in the last 20 years and that present rate of technical success greater than 80%. Moreover radiological embolization shows a low incidence of complications and lower hospitalization cost with respect to surgical treatment. Herein we describe the different techniques of embolization, the indications and the results as appears from the literature and the personal experience. The latter is based on a series of 31 procedures performed in 26 patients, with a rate of technical and clinical success of 93.5%.

Arterial embolization in the treatment of post-traumatic priapism

Priapism is a prolonged penile erection not associated with sexual arousal. Two types of priapism have been described: the more common one is the "veno-occlusive" priapism and can be frequently observed as the consequence of an intracavernosal injection of vaso-active drugs for the treatment of erectile dysfunction. The less common type of priapism is known as "high flow" priapism and usually follows perineal or direct penile trauma. The clinical presentation in case of high flow priapism is quite typical: hystory of recent penile or perineal trauma followed, by the onset of a painless, incomplete and constant erection of the penis. A color-flow Doppler sonogram should be performed as first diagnostic step: this examination allows to identify the presence of patent cavernous arteries and prominent venous drainage with focal area of high flow turbulence along the pathway of one or both the cavernous arteries. An arterial blood sample taken from the corpora will confirm the diagnosis. At first, conservative therapeutical attempts can be suggested, with mechanical external compression of the perineum, the use of ice packs, corporeal aspiration and irrigation with saline. Besides, intracorporeal administration of alpha-agonists and methylene blue should be performed. Unfortunately, these conservative measures often result unsuccessful, and more invasive approaches must be considered. The radiological superselective transcatheter embolization of the proximal artery supplying arterial-lacunar fistula should be the present treatment of choice in these cases of high-flow priapism refractory to conservative and medical treatments. The first successful management of high flow priapism by selective arterial embolization was reported by Wear and coworkers in 1977. Autologous clots and gelatine sponge have been extensively used and become very popular as the embolic agent. More recently, platinum microcoils have been proposed with the aim to achieve more precise and selective embolization. In our single-case-experience on the treatment of high flow priapism by arterial embolization, we used the recently introduced tungsten microcoils. At the time of the follow-up, 2 months later, patient reported satisfactory intercourse with an approximately 75% of penile rigidity. By comparison with microsurgical ligature of the damaged vessel, selective embolization is, at least theoretically, a less invasive procedure, particularly with reference to the trauma caused to the erectile tissue. High-flow priapism is a fairly rare urological pathology which does not require immediate and emergency treatment (as is the case, instead, with venous-occlusive priapism), since the risk of post-ischaemic fibrosis is excluded thanks to the fact that oxygen is supplied to the cavernous tissue. Once the diagnosis has been established with certainty, therefore, the specialist has the necessary time at disposal to arrange for the most appropriate therapeutic steps. When, as is frequently the case, conservative measures prove ineffective, the current treatment of choice for cases of fistula of the cavernous artery would appear to be superselective embolization of the artery, provided same can be performed at specialized centres and by experienced personnel.

Effects of balloon angioplasty and stent implantation on intrarenal echo-Doppler velocimetric indices

This study was aimed at examining whether four intrarenal echo-Doppler velocimetric indices (pulsatility and resistive indices, acceleration and acceleration time) can be useful for assessing the effects of renal artery dilation obtained with either angioplasty or stent implantation. Echo-Doppler studies were performed in 63 hypertensive patients with 68 renal artery stenoses (39 atherosclerotic and 29 fibromuscular) prior to and within five days after the dilation procedures (55 angioplasties, 13 stent implantations), which resulted in an average reduction of arterial narrowing from 79% to 20%. In 24 patients, the velocimetric indices were also examined in relationship to the venoarterial differences of plasma renin activity and of angiotensin II across the stenotic kidneys. We found that after dilation the values of the four indices had returned within the normal range in all but three arteries (one false negative for resistive index and two for acceleration time). However, decrements in acceleration time was the only factor to be significantly correlated with the reduction of arterial narrowing. Moreover, postdilation values of this index were, on average, slightly but significantly higher in arteries that at follow-up developed restenosis rather than in those that remained patent. For similar reductions in arterial narrowing the absolute changes of all indices were similar in atherosclerotic and fibromuscular stenotic arteries and, in a subset of the atheromatous arteries, were also similar after angioplasty and stent implantation. No relationship was found with the changes in the venoarterial differences of plasma renin activity and angiotensin II. It appears that these intrarenal velocimetric indices and, in particular, acceleration time reliably reflect the technical success of renal artery dilation. The acceleration time index may also be valuable for predicting the restenosis of the dilated vessel. None of the indices, however, mirrors the functional consequences of removal of renal artery stenosis as expressed through the changes in transrenal gradients of the components of the renin-angiotensin system.

Percutaneous treatment of iliac aneurysms and pseudoaneurysms with Cragg Endopro System 1 stent-grafts

PURPOSE

To evaluate the feasibility and short-term follow-up results of treating iliac aneurysms by the Cragg Endopro System 1 stent-graft.

METHODS

Nine lesions (two pseudoaneurysms and seven atherosclerotic aneurysms) were treated in eight patients by percutaneous implantation of a total of 10 stent-grafts. The procedure was followed by anticoagulation with heparin for 6 days, then antiplatelet therapy. Follow-up was by color Doppler ultrasound scan at 2 days and 3 months after the procedure for all patients, and by venous digital subtraction angiography and/or angio-CT up to 12 months later for four patients.

RESULTS

Initial clinical success rate was 100% and there were two minor complications. In one case the delivery system was faulty resulting in failure to deploy the stent-graft. An additional device had to be used. At 3-12 months all prostheses were patent but one patient (12.5%) had a minimal pergraft leak.

CONCLUSION

Percutaneous stent-grafting with this device is a safe and efficacious treatment of iliac artery aneurysms.

Superiority of acceleration and acceleration time over pulsatility and resistance indices as screening tests for renal artery stenosis

OBJECTIVE

To compare the accuracy of four echo-Doppler-derived velocimetric indices (pulsatility and resistance indices, acceleration and acceleration time) in detecting renal artery stenosis in hypertensive patients.

PATIENTS AND METHODS

In 73 hospitalized patients with moderate-to-severe hypertension, 18 of whom had normal renal arteries and 55 renal artery stenosis (50-95%) either atherosclerotic (30 cases, five bilateral) or fibromuscular dysplasia (25 cases, two bilateral), we measured the four velocimetric indices using the lateral abdominal approach and sampling Doppler waveforms distally to the stenosis. The diagnostic accuracy of each index was calculated using as cut-off limit the ideal threshold determined with the receiver-operating characteristic curves.

RESULTS

On average all of the indices were altered significantly in arteries with stenosis of both aetiologies with respect to normal arteries, the alterations of pulsatility and resistance indices being, however, less pronounced than those of acceleration and acceleration time, particularly in atherosclerotic stenosis. With the cut-off limits of 0.93, 0.59 and 7.4 m/s2 and 60 ms, respectively, for pulsatility and resistance indices, acceleration and acceleration time, their diagnostic accuracies were 80, 73, 93 and 92%. In stenotic arteries, only the acceleration time was correlated with the degree of arterial narrowing, whereas, in normal arteries, only pulsatility and resistance indices were directly correlated with the age of patients.

CONCLUSIONS

Acceleration and acceleration time are more accurate indices than pulsatility and resistance to screen for renal artery stenosis, probably because their alterations are less attenuated by the counterbalancing effects of age and of atherosclerosis.

Prevention of variceal rebleeding and treatment of liver carcinoma by consecutive transjugular intrahepatic portosystemic shunt and hepatic artery chemoembolization

Variceal bleeding and hepatocellular carcinoma are two severe complications of cirrhosis. One of our patients who bled from oesophageal varices was found to have a malignant hepatic nodule. As the patient refused liver transplantation, a transjugular intrahepatic portosystemic stent was carried out for portal hypertension, and transcatheter arterial chemoembolization for cancer. Both procedures were successful and one year later liver function has not deteriorated. This case shows that intrahepatic stent placement and selective arterial chemoembolization can be safely performed in cirrhotic patients with a solitary hepatocarcinoma nodule and a good liver function reserve.

[Renal arteriovenous fistulae]

Arteriovenous fistulas (AVFs) involving the kidney are rare. They are generally classified as congenital, idiopathic or acquired. The authors present 5 cases of renal arterio-venous communications observed in recent years. These cases don't include the congenital type and represent the forms of AVFs that are more frequently observed (1 idiopathic, 3 iatrogenic, 1 associated with malignancy). This study is aimed at examining the clinical picture and the procedures of detection and monitoring of renal AVFs. The various adopted therapeutic procedures (nephrectomy, surgical ablation, radiological embolization) are analyzed.

The versatility of pectoralis major muscle and musculocutaneous flaps in the reconstruction of the oral cavity and of the anterior chest wall

Musculocutaneous flaps, allowing one stage reconstructions and reducing the stay in hospital and rehabilitation period, have revolutionised modern plastic surgery. Muscle flaps are a good alternative to provide adequate coverage of tissue losses but with limited scarring. The authors report their 5 year clinical experience in the reconstruction of oral cavity and chest wall defects using the pectoralis major as muscle or musculocutaneous flap. The preliminary data of an angiographic study, confirming the segmentation of the pectoralis major muscle into two subunits, each provided with its own vascular supply (mainly the clavicular and the sternocostal segment), are also presented. The short and long-term results confirm the excellent viability and versatility of the pectoralis major musculocutaneous and muscle flap. In particular the complications rate is so low that this procedure can be considered safe and reliable.

Locoregional fibrinolysis using tissue plasminogen activator in 2 cases of acute thrombosis of the renal artery

The use of tissue plasminogen activator gave good results in the treatment of acute coronary thrombosis. Comparable results appear to have been obtained in the first clinical trials in cases of acute thromboses of the peripheral arteries. A successful experiment in the locoregional treatment of acute thrombosis of the renal artery is reported.

[Venous Doppler velocimetry: ten years of development of a method]

Doppler velocimetry enables three haemodynamic parameters that are extremely useful for the study of venous diseases to be evaluated: blood flow direction, the morphology of the velocity wave and venous pressure. These three parameters are used in association depending on the particular requirements of the diagnostic problem. In the case of suspected deep venous thrombosis, study of the morphology of the velocity wave and clinostatism pressure give good diagnostic possibilities for the iliaco-femoral axis but poor for the leg trunks. In post-thrombotic syndrome, Doppler velocimetry is not so useful because the patient has to remain immobile during the examination while this specific pathology features insufficiency of the muscular pump during walking. In varicose disease, the investigation offers a very high diagnostic capability by evidencing the site and extent of valvular incontinence in the saphena and perforating vessels. The only limitation is the presence of numerous incontinent perforating vessels, but this is infrequent. In this pathology, Doppler v. has almost completely supplanted phlebography because it responds to the needs of modern medicine to replace invasive diagnostic investigations with non-invasive techniques that are equally effective. Finally, two other fields of application are very important for this investigation: the study of a patient with varices prior to saphenic stripping and prior to sclerotherapy. Definition of the origin and course of the reflux ways makes an optimal result possible, even allowing for the evolution of varicosity.

Time-course of the changes in blood pressure and in plasma renin activity during the first week after dilation of renal artery stenosis

We measured arterial pressure and plasma renin activity throughout the first week after a technically successful percutaneous transluminal renal angioplasty (PTRA) in 12 patients with hypertension and unilateral renal artery stenosis. Mean arterial pressure fell from 126 +/- 4 to 105 +/- 3 mmHg within 1-2 days of PTRA and stabilized thereafter; in addition, plasma renin activity decreased sharply during the first 2 days after the angioplasty (from 5.2 +/- 2.3 to 1.3 +/- 0.3 ng/ml per h) but continued to decline, reaching 0.8 +/- 0.2 ng/ml per h at the end of the study. When the antihypertensive effect of PTRA was examined in relation to baseline values of plasma renin activity, the patients with low, intermediate and high plasma renin activity showed percentage decreases in mean arterial pressure of, respectively, 6%, 16% and 19% by the sixth day of observation after the angioplasty. No overall correlation was found between the changes in arterial pressure and those in plasma renin activity induced by PTRA. These data suggest that the beneficial effect of PTRA on blood pressure can be estimated within a few days and that the reduction in the activity of the renin system is the principal but not the sole mechanism responsible for it.

[Use of the Kimray-Greenfield filter in the prevention of pulmonary embolism. Personal experience]

Personal experience in the use of intra-caval filters in the prevention of pulmonary embolisms is reported. The advantages and the indications for positioning of the K.G. filter are analysed on the basis of a series of 31 patients operated on with this method.

[Angiodysplasia of the right colon. Angiographic findings in 5 cases]

The authors present five cases of angiodysplasia of the right colon diagnosed by selective arteriography of the superior mesenteric artery. The patients, affected by repeated digestive haemorrhages, underwent angiography after many endoscopic and radiological examinations, all without significative findings. Clinical patterns, methods and angiographic findings are described, together with surgical specimen.

[Diagnostic problems in traumatic rupture of the thoracic aorta. Observations on 8 surgically treated cases]

The authors report their experience concerning the diagnosis of traumatic rupture of the thoracic aorta, based on a review of eight surgically treated cases. They emphasize the importance of the immediate performance of an aortography which, providing highly specific findings, permits the diagnosis of this serious lesion, which is often misrecognized. The diagnostic value of the standard chest roentgenogram is discussed, with special attention to mediastinal enlargement which (especially if associated with a CT finding of a periaortic haematoma) must lead to the performance of an aortography, even in those cases with atypical or absent symptoms. Following this diagnostic approach, an early surgical treatment of the aortic lesions, with favorable results in five out of eight cases was obtained.