Chet R. Rees

Mesenteric angioplasty in the treatment of chronic intestinal ischemia

PURPOSE This study was undertaken to determine the safety and efficacy of percutaneous transluminal angioplasty (PTA) in the treatment of chronic mesenteric ischemia (CMI) in very high-risk surgical patients. METHODS Twenty-four focal mesenteric stenoses treated from 1984 to 1994 by PTA in 19 patients with CMI were reviewed. All 19 patients were considered poor surgical candidates. Seventeen patients had classic symptoms of CMI, and two patients had atypical abdominal complaints. Vessels dilated included the superior mesenteric artery (18), celiac artery (3), inferior mesenteric artery (1), aorta-superior mesenteric artery vein graft (1), and aorta-splenic artery vein graft (1). Complete follow-up was possible in all patients, with the exception of one patient who had no symptoms when last seen 17 months after the procedure. RESULTS PTA was technically successful in 18 of 19 patients (95%) and 23 of 24 stenoses (96%). The lone technical failure resulted in superior mesenteric artery dissection with thrombosis and bowel infarction; the patient died despite emergent laparotomy and revascularization (mortality rate, 5%). Complete symptomatic relief was attained in 15 patients (79%), with follow-up showing continued relief of symptoms for a mean of 39 months (range, 4 to 101 months). Partial symptomatic relief was attained in three patients. Recurrent symptoms developed in three patients (20%) at a mean interval of 28 months (range, 9 to 43 months). Repeat PTA performed in two patients provided good technical results and relief from clinical symptoms. One patient had a symptomatic axillary sheath hematoma that required surgical decompression. CONCLUSIONS Mesenteric PTA is a valuable treatment option in patients who have CMI and are considered very high operative risks. The initial technical success rate is excellent, with the majority of patients having complete symptomatic improvement and continued relief of symptoms at short-term follow-up.

Angioplasty and stenting of completely occluded iliac arteries

Percutaneous angioplasty and placement of balloon-expandable intraluminal stents were performed in 12 iliac occlusions in 12 patients. Indications were limb salvage in seven and claudication in five. After successful stenting, ankle-brachial indexes improved by 0.15 or more in 11 of 12 patients (mean increase, 0.40), transstenotic pressure gradients decreased to less than 5 mm Hg (mean, 0.58 mm Hg) in all patients, and improvement in clinical grade was seen in all patients. At follow-up at 1-14 months (median, 6 months), ankle-brachial indexes were stable (mean, 0.95), and clinical grades were unchanged in all patients. Complications occurred in two patients; both experienced distal embolization, and one, who was receiving corticosteroid therapy, also suffered stent thrombosis. Local surgical embolectomy was successful in both patients, and the thrombosed stent was recanalized with urokinase. This early experience suggests that stenting may play an important role in the management of iliac occlusions, especially in poor surgical candidates.

Stents for atherosclerotic renovascular disease

There is extensive documentation of excellent clinical results with renal stents in patients who have technically failed angioplasty and who would have been expected to otherwise have a high incidence of clinical failure. In addition, the technical success of renal stents is vastly superior to that of conventional angioplasty in atherosclerotic renovascular disease, and stents have been a major factor in making the endovascular treatment of ASRVD both practical and reliable in experienced hands. Restenosis rates appear roughly equivalent or lower for stents versus PTA as far as can be determined without good comparative studies. Restenosis appears to be decreasing to 15%-20% in more recent series, perhaps because of the accumulation of knowledge regarding patient selection and techniques. It is, therefore, clear that the use of stents to treat technical failures of angioplasty will result in overall improved patency in the treated population; however, it remains to be determined whether stents should be routinely placed with the intention of inhibiting restenosis, in the presence of technically successful angioplasty with minimal residual stenosis or pressure gradient. Such a determination may require comparative study that is more complicated than a simple randomized comparison of angioplasty versus stents.

Metallic Stents for the Treatment of Intrahepatic Biliary Strictures after Liver Transplantation

PURPOSE The authors report their results with use of metallic stents for the treatment of intrahepatic biliary strictures occurring after liver transplantation. PATIENTS AND METHODS Twenty-four patients with intrahepatic biliary strictures after liver transplantation were treated with metallic stents. Eleven had undergone prior unsuccessful percutaneous balloon dilation. Successful stent deployment occurred in all subjects. Gianturco, Wallstents, and Palmaz stents were used. Follow-up was obtained in all 24 patients. RESULTS Initial technical success was obtained in all 24 patients. In 11 patients, long-term primary, primary assisted, or secondary stent patency was achieved with follow-up ranging from 17 to 58 months. Ten patients died or underwent retransplantation within 14 months for reasons unrelated to their stents. In three patients, stent placements failed because of stent obstructions that were refractory to attempts at secondary patency. By life-table analysis, cumulative primary, primary assisted, and secondary patency rates were 50%, 61%, and 80%, respectively, at 18 months. CONCLUSION Metallic biliary stents offer promising results for intrahepatic strictures in the posttransplant patient, particularly in patients with widespread strictures. Stents can become partially or totally obstructed due to sludge and debris, but patency can often be restored with additional interventional techniques.

A comparison of treatment with transjugular intrahepatic portosystemic shunt or distal splenorenal shunt in the management of variceal bleeding prior to liver transplantation

Recurrent variceal bleeding in liver transplant candidates with end-stage liver disease can complicate or even prohibit a subsequent transplant procedure (OLT). Endoscopic sclerotherapy and medical therapy are considered as first-line management with surgical shunts reserved for refractory situations. Surgical shunts can be associated with a high mortality in this population and may complicate subsequent OLT. The transjugular intrahepatic portosystemic shunt (TIPS) has been recommended in these patients as a bridge to OLT. This is a new modality that has not been compared with previously established therapies such as the distal splenorenal shunt (DSRS). In this study we report our experience with 35 liver transplant recipients who had a previous TIPS (18 patients) or DSRS (17 patients) for variceal bleeding. The TIPS group had a significantly larger proportion of critically ill and Child-Pugh C patients. Mean operating time was more prolonged in the DSRS group (P = 0.014) but transfusion requirements were similar. Intraoperative portal vein blood flow measurements averaged 2132 +/- 725 ml/min in the TIPS group compared with 1120 +/- 351 ml/min in the DSRS group (P < 0.001). Arterial flows were similar. Mean ICU and hospital stays were similar. There were 3 hospital mortalities in the DSRS group and none in the TIPS group (P = 0.1). We conclude that TIPS is a valuable tool in the management of recurrent variceal bleeding prior to liver transplantation. Intraoperative hemodynamic measurements suggest a theoretical advantage with TIPS. In a group of patients with advanced liver disease we report an outcome that is similar to patients treated with DSRS prior to liver transplantation. The role of TIPS in the treatment of nontransplant candidates remains to be clarified.

Comparison of a Suspended Radiation Protection System versus Standard Lead Apron for Radiation Exposure of a Simulated Interventionalist

PURPOSE To evaluate the radiation protective characteristics of a system designed to enhance operator protection while eliminating weight to the body and allowing freedom of motion. MATERIALS AND METHODS Radiation doses to a mock interventionalist were measured with calibrated dosimeters in a clinical interventional suite. A standard lead apron (SLA; Pb equivalent, 0.5 mm) was compared with a suspended radiation protection system (ZeroGravity; Zgrav) that shields from the top of the head to the calves (except the right arm and left forearm) with a complex overhead motion system that eliminates weight on the operator and allows freedom of motion. Zgrav included a suspended lead apron with increased lead equivalency, greater length, proximal left arm and shoulder coverage, and a wraparound face shield of 0.5 mm Pb equivalency. A 26-cm-thick Lucite stack (ie, mock patient) created scatter during 10 controlled angiography sequences of 120 exposures each. Parameters included a field of view of 40 cm, table height of 94 cm, 124 cm from the tube to image intensifier, 50 cm from the image center to operator, 66 kVp, and 466-470 mA. RESULTS Under identical conditions, average doses (SLA vs Zgrav) were 264 versus 3.4 (ratio, 78) to left axilla (P < .001), 456 versus 10.2 (ratio, 45) to left eye (P < .001), 379.4 versus 6.6 (ratio, 57) to right eye (P < .005), and 18.8 versus 1.2 (ratio, 16) to gonad (P < .001). CONCLUSIONS Relative to a conventional lead apron, the Zgrav system provided a 16-78-fold decrease in radiation exposure for a mock interventionalist in a simulated clinical setting.

Balloon-Expandable Intraarterial Stents: Effect of Antithrombotic Medication on Thrombus Formation

Growing interest in the research of percutaneous intravascular metallic stents is evidenced by the rapidly increasing number of investigations on the subject [1–6]. Sigwart et al. [7] first demonstrated successful clinical use of intracoronary stents. However, recent reports indicate thrombosis of the stent after placement in 39% of the series by Puel et al. [8] and 11% in the series by Sigwart et al. [9]. This underscores the fact that thrombogenicity may be one of the most challenging problems for the safe use of intravascular stents.

Effect of a Transjugular Intrahepatic Portosystemic Shunt on Liver Biochemical Profiles

PURPOSE Transjugular intrahepatic portosystemic shunts (TIPS) have markedly simplified the care of patients with refractory variceal bleeding. Follow-up of liver biochemical profiles, however, has not been done in a prospective fashion. PATIENTS AND METHODS Twenty-nine patients undergoing TIPS placement for refractory variceal bleeding underwent serial laboratory tests and assessment of encephalopathy to determine the effect of TIPS. Prothrombin time and aspartate aminotransferase, alanine aminotransferase, total bilirubin, alkaline phosphatase, serum albumin, serum creatinine, and venous ammonia levels were checked prior to the procedure, at the time of discharge, and at 3 weeks, 3 months, and 6 months following the procedure. RESULTS There was no statistically significant change in any of the obtained laboratory values at up to 6 months of follow-up. The change in aspartate aminotransferase level approached but did not reach statistical significance at the time of discharge and was thought to be secondary to hepatocellular trauma associated with the procedure. New onset of encephalopathy occurred in 18.2% of patients and was easily controlled with medical therapy. CONCLUSIONS TIPS does not appear to have a significant effect on the liver biochemical profile with short-term follow-up. Hepatic encephalopathy does occur, however, in a significant number of patients but is easily controlled with medical therapy.

The hemodynamic effects of the administration of ionic and nonionic contrast materials into the pulmonary arteries of a canine model of acute pulmonary hypertension

Clinical studies have shown pulmonary and right ventricular hypertension to be important factors increasing the risk to patients during pulmonary angiography. This experiment was undertaken to define the hemodynamic changes induced by the administration of contrast material into the pulmonary arteries of dogs with embolic pulmonary hypertension, and to compare the effects of ionic and nonionic agents. Ten closed-chest dogs under light halothan anesthesia were subjected to pulmonary embolization with sephadex microspheres until severe pulmonary hypertension occurred and the cardiac output decreased to 50%-60% of the pre-embolization baseline. Intra-pulmonary injections of contrast material were performed in eight animals while hemodynamic indices were measured. Sodium methylglucamine diatrizoate induced severe, transient, hypotension associated with a large decrease in systemic vascular resistance and little change in the cardiac output. Hypotension is especially undesirable in the presence of pulmonary hypertension because it worsens the preexisting coronary ischemia and compromised right ventricular function. No elevation in mean pulmonary artery pressure was seen, and pulmonary vascular resistance decreased. Iohexol induced milder effects, perhaps because it exerts a less severe systemic vasodilatory effect and is not a negative inotrope. These findings suggest iohexol may be safer in the high risk patient, however, these data may not be directly applied to unanesthetized humans.

Inferior Vena Cava Stent Resolves Hepatopulmonary Syndrome in an Adult with a Spontaneous Inferior Vena Cava-Portal Vein Shunt

Hepatic encephalopathy and hepatopulmonary syndrome are classically seen in patients with cirrhosis and hepatic synthetic dysfunction. However, they can be caused by vascular anomalies that shunt blood away from the liver. In these settings, the vascular anomalies most often require surgical correction or liver transplantation. However, we report a case of a 43-year-old male with hepatic encephalopathy and hepatopulmonary syndrome from a type 2 Abernethy malformation that was corrected with an inferior vena cava (IVC) stent.