Carbon dioxide as an angioscopic medium. Comparison to various methods of saline delivery.

The limitations of angiography, when it is used as the sole method of vascular assessment, are increasingly apparent as vascular intervention becomes more sophisticated. Angioscopy could be an adjunctive diagnostic modality by differentiating among thrombus, dissection, and atheroma, and by monitoring the response to therapy. However, angioscopy requires a blood-free field for adequate visibility, and this may be difficult to obtain. The feasibility of carbon dioxide (CO2) and various saline delivery methods for clarifying the viewing field for percutaneous angioscopy was investigated. Angioscopy of femoral and iliac arteries on nine dogs was performed. Saline was infused by hand injection, pressure bag infusion, or mechanical power injection, and CO2 gas was injected using a special gas injector. The clarity of the viewing field was graded for each medium and method. Excellent quality antegrade femoral angioscopy was obtained with CO2. The superiority of CO2 injection in comparison with power-injected saline approached statistical significance (P = .06). Power-injected CO2 and power saline were superior to hand-injected or pressure bag-injected saline for maintaining sufficient visibility. Retrograde iliac angioscopy was possible without inflow occlusion, but required high flow rates (only possible with power-injected saline or CO2). CO2 injected under controlled circumstances holds promise as a medium to improve angioscopic visibility.

Effects of carbon dioxide arterial infusion on hepatic biochemistry and histology in a rabbit model.

RATIONALE AND OBJECTIVES: The objective of this study was to determine the effect of carbon dioxide (CO2) infusion on hepatic biochemistry and histology in a rabbit model. METHODS: The study population consisted of 24 anesthetized rabbits that received hepatic infusion of either CO2 or saline (control) at doses of 10 mL/kg, comparable with those doses used in human clinical trials. Blood for clinical chemistry analysis was collected at baseline, 1 hour, 24 hours, and 168 hours (7 days) postprocedure. The rabbits were killed at 7 days postprocedure and the liver examined histologically for hepatic damage. RESULTS: There were no significant differences between the CO2 and the control groups in dorsal, ventral, and dorsal/ventral scores. Increases in alanine, an important indicator of hepatocellular membrane injury, in the CO2 group were significantly greater at 1 hour and 24 hours posttreatment (P = 0.037 and 0.013). However, the mean levels at 168 hours (7 days) were not significantly different (P = 0.22). The increases at 1 and 24 hours were small, transient, and considered clinically insignificant. CONCLUSION: No long-term hepatic effects in these animals were suggested by biochemical and histological examinations.

Standardized measurement of the future liver remnant prior to extended liver resection: methodology and clinical associations.

BACKGROUND: There is no agreement regarding the preoperative measurement of liver volumes and the minimal safe size of the liver remnant after extended hepatectomy. METHODS: In 20 patients with hepatobiliary malignancy and no underlying chronic liver disease, volumetric measurements of the liver remnant (segments 2 and 3 +/- 1) were obtained before extended right lobectomy (right trisegmentectomy). The ratios of future liver remnant to total liver volume were calculated by using a formula based on body surface area. In 12 patients, response to preoperative right trisectoral portal vein embolization was evaluated. In 15 patients who underwent the planned resection, preoperative volumes were correlated with biochemical and clinical outcome parameters. RESULTS: The future liver remnants increased after portal vein embolization (26% versus 36%, P < .01). Smaller size liver remnants were associated with an increase in postoperative liver function tests (P < .05) and longer lengths of hospital stay (P < .02). Preliminary data indicates an increase in major complications for liver volumes < or = 25% (P = .02). CONCLUSIONS: A simple method of measurement provides an assessment of the liver remnant before resection. It is useful in evaluating response to portal vein embolization and in predicating the outcome before extended liver resections.

Absolute ethanol renal angioinfarction for control of hypertension.

Six patients (11 renal units) underwent ethanol renal angioinfarction for medically uncontrollable hypertension. The mean preablation blood pressure was 175/112 mm Hg despite antihypertensive medications. Five of the patients demonstrated elevated renal vein renin levels prior to angioinfarction. Hypertension was improved in all 6 patients, during a mean follow-up period of fifty-one months. Systemic hypertension was completely eliminated in 4 patients. Two patients continue to require antihypertensive medication to control their hypertension. There were no major complications directly related to intra-arterial injection of ethanol. Transcatheter renal ablation employing intra-arterial injection of absolute ethanol for control of severe hypertension appears to be a safe and efficacious procedure. It should be considered an alternative to nephrectomy in selected high-risk patients.

Hawkins-Hunter retrograde transcutaneous nephrostomy: a new technique.

Retrograde nephrostomy, a new technique to aid in stone management, has been performed successfully in dogs. It has also been used without complication in a human patient to help remove a renal stone percutaneously under local anesthesia. The technique consists of placing a coaxial catheter over a guidewire under fluoroscopy into the exact calyx desired and advancing a long needle out to the skin to establish a transcutaneous tract. The advantages of the technique include increased control and precision of tract placement, efficient working angles for percutaneous stone removal, and the ability to perform the procedure under local anesthesia.

New monofilament basket for bladder calculi.

Successful stone manipulation was facilitated with the new monofilament basket in experimental situations and in patients. Advantages over other baskets include: in vivo adjustability, reduced mucosal trauma, ability to irrigate and aspirate through the basket, and ability to pass lithotriptor electrodes within the basket. Basket modifications under study might prove useful within the ureter, renal pelvis, and biliary tree.

Current status of carbon dioxide angiography.

The current status of carbon dioxide as an angiographic contrast agent is reviewed in this article. The physical characteristics of intravascular carbon dioxide, pertinent physiology, and principles of imaging are discussed. In addition, the advantages and limitations of carbon dioxide are compared with those of iodinated contrast. Examples of diagnostic and therapeutic procedures in both the arterial and venous systems show the utility of carbon dioxide angiography.

Evaluation of percutaneous transhepatic balloon dilatation of benign biliary strictures in high-risk patients.

During the period from 1979 through 1984, 17 patients with benign biliary strictures underwent percutaneous transhepatic balloon dilatation. All patients presented with either hyperbilirubinemia and acute cholangitis, a history of intermittent chills and fever, or both. Balloon dilatation was most successful in those patients with intrahepatic strictures, sclerosing cholangitis, strictured biliary enteric anastomoses, and distal common bile duct strictures with retained calculi. Two patients with postsurgical common bile duct injury had treatment failure 3 and 18 months after dilatation and subsequently underwent elective hepaticojejunostomy. Although our longest treatment success is now more than 4 1/2 years in an 83 year old woman who is 15 years posthepaticojejunostomy, the mean follow-up of the entire group has only been 2 years. On the basis of our early experience and that of others, we now recommend an initial attempt at balloon dilatation in most patients with postsurgical benign biliary strictures. Further technical advances and longer follow-up in present and future series may certainly broaden the appeal of this nonoperative procedure.

Angiography of the lower extremity in atherosclerotic vascular disease. Current techniques.

With the vast array of technology available, detailed diagnostic information is now routinely obtained in patients with peripheral vascular disorders. In addition, percutaneous intervention and advanced surgical techniques now safely permit the patient to return to an active life, and in advanced vascular disease, the extremity can be salvaged when previously the only option was amputation. We feel strongly that the maximum amount of information about the arterial system should be obtained throughout the patient's management. In addition, these complex procedures require considerable experience and judgment, and our practice of ongoing communication with the vascular surgery staff during both the diagnostic and the therapeutic phases of the patient's treatment has been extremely beneficial.

Angiography with carbon dioxide (CO2).

CO2 possesses many advantages over conventional iodinated contrast agents used for arteriography. It is nonallergic and lacks renal toxicity. Its unique properties permit use of smaller catheters in diagnostic and therapeutic angiographic procedures, allow optimal vascular imaging of various neoplasm, assist in detection of occult gastrointestinal bleeding, and facilitate TIPS procedures. With digital subtraction techniques and stacking programs, CO2 arteriography is as accurate as iodinated contrast studies in most patients and thus is the preferred arterial imaging technique in patients with contrast allergy and renal insufficiency. CO2 is also extremely inexpensive compared with available contrast agents. Understanding of the effects of buoyancy and compressibility is necessary for safe, controlled delivery of CO2 during arteriography, but only rare complications have occurred in our large experience with CO2 angiography. Thus, use of CO2 as an arterial contrast agent significantly expands the safety and utility of arterial imaging in patients with peripheral vascular disease.

Angiographic findings in some rare pancreatic tumors.

Angiographic findings in one giant cell carcinoma, one cystadenocarcinoma, one poorly vascularized mucinous cystadenocarcinoma, as well as in two avascular (gastrin- and glucagon-producing) islet-cell tumors of the pancreas are described. Two hypervascularized islet-cell tumors are presented for comparison and a case of tumorous chronic pancreatitis in a child is reported because ot its rarity. The aggressiveness of the giant cell carcinoma of the pancreas was demonstrated by its expansive growth. In the case of cystadenocarcinoma angiography revealed the tumor with hepatic metastases not diagnosed at explorative laparotomy. The relative hypovascularity in the case of mucinous cystadenocarcinoma was unusual. Both avascular islet-cell tumors simulated a pancreatic pseudocyst and the final diagnosis was made only by immunoassay. Chronic pancreatitis in a child presented with marked hypervascularization.

Prognostic value of angiography in management of severe acute renal transplant rejection.

Angiograms of 34 kidney transplant patients with progressive decrease in renal function after multiple doses of intravenous methylprednisolone (MP) were evaluated retrospectively in regard to the prognostic value of angiography. The following parameters were included in evaluation: prolonged arterial washout time, large vessel vasculitis, presence of arteriovenous shunting, poor cortical perfusion as evidenced by non-filling of cortical vessels, poor definition of cortico-medullary junction, and a poor nephrogram. When 1 to 3 of these abnormalities existed in angiogram, 67% of living related donor transplants (LRD) recovered under continued MP-therapy. With 4-6 angiographic abnormalities the recovery rate was reduced to 30%. The overall recovery rate for LRD transplants was 44%. Cadaveric transplants (CAD) had a statistically significant poorer prognosis as evidenced by only 8% recovery rate under continued MP-therapy.

Carbon dioxide digital subtraction angiography: the practical approach.

CO(2) has developed into a viable alternative to iodinated contrast for digital vascular imaging. Because CO(2) is a gas, it has a unique set of properties that affords certain advantages over iodinated contrast in a variety of settings. However, if CO(2) is used inappropriately, these same properties are associated with a unique set of rare but potentially harmful events. Therefore, it is essential that these unique characteristics be understood in order to employ a few simple precautionary measures. Fortunately, there is a delivery system currently available that is readily assembled and easy to use that ensures the appropriate administration of CO(2). This system, combined with experience, can reduce the greater labor intensity sometimes associated with CO(2) digital subtraction angiography. When it is used appropriately, CO(2) digital subtraction angiography alone or in combination with iodinated contrast offers diagnostic and interventional rewards that are not available with traditional intravascular contrast examinations.