Biomedical subjects
Publications and source records attributed to O H Gutierrez.
A 32-year-old woman suffered a right femoral artery embolic occlusion from an abdominal aortic mural thrombus associated with caval perforation by a stainless steel Greenfield Filter. The complication required thrombolytic therapy, surgical revascularization, and long-term anticoagulation.
RATIONALE AND OBJECTIVES: We examined the changes in luminal diameter and vasa vasorum after stent dilation of the aorta of nonatherosclerotic rabbits. METHODS: Balloon-expandable stents were placed in the aortas of rabbits at the L3 level and were expanded. After 8 weeks, the rabbits were euthanized, perfused with barium sulfate particles, frozen, sectioned, and X-rayed. RESULTS: The luminal intrastent diameter (2.3 +/- 0.23 mm) was significantly different (p < .05) from the expanded stent diameter but was not different from the luminal diameter above (2.3 +/- 0.53 mm) and below (1.9 +/- 0.18 mm) the stent. The number of vasa vasorum at the stent (46 +/- 7.2) was significantly increased compared with above (21 +/- 4.8, p < .001) and below (14.4 +/- 4.6, p < .001) the stent. CONCLUSION: After 8 weeks, luminal diameter was uniform. The increased vasa vasorum in the stented section suggested an increase in blood flow to the aortic wall, which may be important to the remodeling process.
RATIONALE AND OBJECTIVES: We evaluated the changes in the down-stream Doppler waveforms caused by a proximal stenosis in the main renal artery of dogs. METHODS: Renal parenchymal arterial waveforms downstream from mild (< 50%), moderate (50-75%), and severe (76-95%) stenoses were compared with nonstenotic baseline waveforms in five mongrel dogs. Waveform shapes were categorized as biphasic or monophasic. The percentage of biphasic and monophasic waveforms was determined for each stenosis. The acceleration index (AI) and the acceleration time (AT) were determined using traditional and modified calculations (AI' and AT'). Late systolic deceleration (DS), diastolic deceleration (DD), and the resistive index (RI) also were measured. RESULTS: AT, AI', and AT' demonstrated significant differences between the severe stenoses and nonstenotic baselines (p < .05); however, there was no difference between the mild and moderate stenoses versus baselines. The percentage distribution of monophasic and biphasic waveforms was highly correlated with the degree of stenosis. Monophasic waveforms increased on average from 22.5% of baseline waveforms to 76.5% of waveforms in the severe stenoses. Biphasic waveforms decreased on average from 69.9% of baseline waveforms to 18.7% of waveforms in the severe stenoses. CONCLUSION: Quantitative evaluation of the downstream waveform parameters (AI, AT, AI', AT', DS, DD, and RD in the dog kidney is not sufficiently accurate, but calculation of the percentage of the monophasic and biphasic waveforms present may be useful to predict a hemodynamically significant renal artery stenosis (> or = 50%).
PURPOSE: Despite the widespread use of intraarterial thrombolytic therapy for peripheral arterial occlusive disease, a randomized study comparing its efficacy with that of operative intervention has never been performed. This study evaluates the potential of intraarterial urokinase infusion to provide clinical benefits in patients with acute peripheral arterial occlusion. METHODS: Patients with limb-threatening ischemia of less than 7 days' duration were randomly assigned to intraarterial catheter-directed urokinase therapy or operative intervention. Anatomic lesions unmasked by thrombolysis were treated with balloon dilation or operation. The primary end points of the study were limb salvage and survival. RESULTS: A total of 57 patients were randomized to the thrombolytic therapy group, and 57 patients were randomized to the operative therapy group. Thrombolytic therapy resulted in dissolution of the occluding thrombus in 40 (70%) patients. Although the cumulative limb salvage rate was similar in the two treatment groups (82% at 12 months), the cumulative survival rate was significantly improved in patients randomized to the thrombolysis group (84% vs 58% at 12 months, p = 0.01). The mortality differences seemed to be primarily attributable to an increased frequency of in-hospital cardiopulmonary complications in the operative treatment group (49% vs 16%, p = 0.001). The benefits of thrombolysis were achieved without significant differences in the duration of hospitalization (median 11 days) and with only modest increases in hospital cost in the thrombolytic treatment arm (median $15,672 vs $12,253, p = 0.02). CONCLUSIONS: Intraarterial thrombolytic therapy was associated with a reduction in the incidence of in-hospital cardiopulmonary complications and a corresponding increase in patient survival rates. These benefits were achieved without an appreciable increase in the duration of hospitalization and with only modest increases in hospital cost, suggesting that thrombolytic therapy may offer a safe and effective alternative to operation in the initial treatment of patients diagnosed with acute limb-threatening peripheral arterial occlusion.
The use of Thorotrast as a contrast medium is now of historical interest. Thorotrast-induced angiosarcoma, though rare, still generates considerable clinical interest because of the characteristic opacification of the liver, spleen, and lymph nodes, and the long latency period between exposure and the onset of the tumor. We present a case of hepatic angiosarcoma which developed 37 years after the administration of Thorotrast.
Acquired coronary artery microvascular fistulas have been reported in only a few patients after myocardial infarction. We describe 1 patient in whom serial coronary angiography demonstrated the development of coronary angiogenesis at the site of an old myocardial infarction. The area of neovascularity was associated with a large apical left ventricular thrombus. This finding suggests that growth-promoting mitogens are present in myocardium and thrombus and that angiogenesis occurs in some patients following myocardial infarction.
In 17 elderly patients, 19 angioplasties (17 nonostial, 2 ostial) were performed to treat acute decreases in renal function caused by high-grade renal artery stenosis in patients considered to be high-risk surgical candidates. Seventeen angioplasties (percutaneous transluminal renal angioplasty, PTRA) were technically successful and 7 patients showed improved renal function, as reflected by a fall in mean serum creatinine from 566 to 180 mumol/l (6.4 to 2.1 mg/dl). Four others had stabilization of function and 3 out of 4 with acute oliguria improved. Complications included femoral hematoma (4), minor peripheral embolism (3), renal artery thrombosis (1) renal artery dissection (1). One fatal complication was thrombosis of the aortic bifurcation due to catheterization. Four other patients died of cardiovascular causes unrelated to PTRA. Eleven patients experienced stabilization or improvement in renal function, but five out of six PTRA failures required maintenance hemodialysis and died in the hospital. Percutaneous transluminal angioplasty may offer the best change of favorable outcome in selected severely ill elderly patients with uremia, hypertension and renal artery stenosis.
Transcatheter intraportal infusion of chemotherapy in a patient with metastatic liver disease resulted in erosion of the tip of the catheter into the biliary system within six months of its placement. This unusual complication adds to the disadvantages of direct portal administration of chemotherapeutic agents in the treatment of hepatic tumors.
One hundred patients with computed tomographic (CT) evidence of liver metastases (and confirmation by biopsy or progression of disease) had serum levels of alkaline phosphatase, serum glutamic oxaloacetic transaminase, and serum glutamic pyruvic transaminase measured within two weeks of scanning. All three enzymes were within the normal range in 33% of patients. Even with advanced involvement (defined as three or more metastatic lesions over 3 cm in diameter), 20% of patients had normal levels of all three liver enzymes. Although liver function tests (LFTs) (enzyme levels) are inexpensive and simple to perform, they failed to detect a significant number of patients with liver metastases.
A case of mesenchymal hamartoma of the liver in a 30-year-old female is reported. Ultrasonography, computed tomography, and hepatic angiography demonstrated the presence of a large, mixed cystic and solid mass within the liver, suggesting the diagnosis of a mesenchymal hamartoma. At surgery, the tumor proved to be unresectable.
Fistulas between the coronary artery and the left heart chambers are exceptionally rare, especially those emptying into the left ventricle. We know of 33 cases of coronary artery-left ventricular fistulas reported in the literature, 7 of which had multiple communications. The findings in 6 additional patients with multiple coronary artery-left ventricular fistulas are reported. Three of the 6 patients from all three major coronary arteries. It is important to recognize this anomaly as it may be the source of angina in patients without angiographic evidence of major atherosclerotic coronary artery disease.
Nonsurgical intrahepatic shunts between the left portal vein and left hepatic vein were created in seven dogs with portal hypertension by means of a Grüntzig angioplasty catheter with a balloon diameter of 12 mm. This catheter was introduced coaxially through a stiff 18-French Teflon catheter (diameter, 6 mm) using transjugular approach. The procedure had to be repeated in weekly intervals up to five times (range, one to five times; average, 2.4 times) until an intrahepatic shunt remained permanently open. Animals with open intrahepatic shunts were followed for one month to one year. Immediately after production of an intrahepatic shunt, the portal pressure fell from 23.7 +/- 3.5 cm of water to 10.6 +/- 1.4 cm of water, and remained in that range during the follow-up period. Portal blood flow increased at the same time from 9.1 +/- 2.9 mL/min/kg to 15.1 +/- 3.5 mL/min/kg. One week after successful shunt production, a second, more gentle rise of portal flow began. It lasted several weeks and was accompanied angiographically by a corresponding increase in shunt diameter. At necropsy, a smooth transition between the intima of the portal and hepatic vein and the shunt was found. Histologically, the endothelialized shunt consisted of granulation tissue with collagen deposition at one month and of fibrous connective tissue three months and later.
Four patients with a total of six mycotic aneurysms of the aorta were examined with computed tomography (CT) after intravenous contrast material enhancement, and with abdominal or thoracic aortography. In the three patients with mycotic aneurysms involving the abdominal aorta, CT scans showed a vascular paraaortic structure without calcified walls adjacent to a nondilated aorta, and a large non-contrast-enhanced retroperitoneal mass representing inflammatory tissue and blood from a contained aortic rupture. A CT scan of one aneurysm of the thoracic aorta demonstrated an enhanced saccular mass originating from the aorta without paraspinal component. In three of four patients, the CT findings were corroborated by aortographic evidence of an eccentric aneurysmal sac in an atypical location for atheromatous disease. In four patients with clinical manifestations suggesting mycotic aneurysm of the aorta, a combination of CT and angiographic imaging provided accurate diagnostic information for planning adequate and early surgical treatment.
The hemodynamic effects of prostaglandins PGA1, PGE1, PGE2, and PGF2 alpha on the splanchnic circulation were evaluated in five chronic dogs with portal hypertension, periportal fibrosis, and portosystemic venous shunting. The maximum effect was achieved with dosages of 2 micrograms/kg/min after bolus injection into the superior mesenteric artery. With this dosage a monophasic increase of portal blood flow and pressure was found with PGA1, PGE1, and PGE2, whereas PGF2 alpha caused a biphasic response: an initial decrease in portal blood flow and pressure was followed by an increase in these parameters. The average peak increase in portal blood flow and pressure was similar for PGE1 and PGF2 alpha, and significantly smaller for PGA1 and PGE2. Average peak iodine concentrations in the portal blood after superior mesenteric angiography were highest with PGF2 alpha, similar for PGE1 and tolazoline, and lowest in controls. The vasoconstrictor effect of PGF2 alpha is, overall, reduced and less reproducible when compared with vasopressin. This investigation suggests that both PGE1 and PGF2 alpha are effective for improved arterial portography, the latter agent appearing superior. On the other hand, PGF2 alpha cannot be recommended as a therapeutic agent for the treatment for gastrointestinal and particularly variceal bleeding.
Periportal fibrosis and portal hypertension were induced by periodic retrograde biliary injections of sesame oil for two to three months in 12 cholecystectomized dogs equipped with Thomas cannulas. Stable portal hypertension between 18 and 24 cm of water occurred in four of 12 dogs (baseline: 10.4 +/- 0.5 cm of water); the remaining eight dogs required continuous biliary oil injections to maintain the portal pressure in that range. Portosystemic venous collaterals were first seen three weeks after the initial biliary oil injection and were extensively developed after two months. Hepatopetal portal blood flow decreased 61 +/- 5% during the first six months, with the greatest decrease of 32 +/- 4% occurring in the first month. Hepatic arterial flow did not change in the first month and then began to rise slowly to peak at nine months at 170 +/- 32% of its baseline value. The greatest increase in hepatic arterial flow was found between the sixth and ninth month when the portal flow no longer changed significantly. Hepatic fibrosis originating from the portal triads and around extravasated oil droplets appeared to progress slowly during the entire observation period. Animals with advanced hepatic fibrosis remained in satisfactory general health with liver enzymes usually remaining in the high normal to low pathologic range, allowing extensive follow-up examinations at regular intervals.
Continuous wave (CW) and pulsed Doppler ultrasound studies with spectral analysis were used to detect the left coronary arterial blood flow in patients who were undergoing routine echocardiography. The pulmonary artery is a stable ultrasonic landmark from which detection of the blood flow can be effected. The left coronary artery can be distinguished by its blood flow toward the cardiac apex and by specific, functional flow features. Flow patterns vary among the left main, circumflex, and anterior descending arteries; patterns also vary with respiration cycles. In the present study, coronary arterial blood flow was detected in 58 of 70 patients (83%). Findings were validated by selectively injecting an agitated saline contrast medium into the left coronary artery and, in another study, by comparing human Doppler phasic flow waveforms with electromagnetic flowmeter recordings obtained in dogs.
Diatrizoate, iopamidol and ioxaglate were compared in five normal dogs and in five dogs with presinusoidal cirrhosis and portal hypertension for arterial portography. After selective injection of 40 ml of each contrast agent in iodine concentrations of 320 mg per ml into the superior mesenteric artery, portal vein blood samples were collected in 2-second intervals and the iodine concentrations determined using x-ray energy spectrometry. The highest iodine concentrations in the portal blood were found in both normal portal pressure and portal hypertension with ioxaglate, followed by iopamidol and diatrizoate in this order. Compared with diatrizoate, ioxaglate and iopamidol increased the peak portal blood iodine concentrations 45% and 22%, respectively. The use of ioxaglate in arterial portography should show the portal system at least as well as when a conventional contrast agent is used together with a vasodilator such as tolazoline.
Portal blood iodine concentrations and the radiographic visualization of the portal vein were compared in five dogs (50 portograms). The portal blood iodine concentrations required for a certain degree of portal vein opacification varied considerably. However, an overall significant difference was found in the portal blood iodine concentrations of different degrees of portal vein visualization. An increase in the portal blood iodine concentrations from 0 to 30 mg per ml was associated with an overall improvement of the portal vein visualization. With a blood iodine concentration of 30 mg per ml, an excellent visualization of the portal system was always achieved that could no longer be improved by further increasing the portal blood iodine concentration up to 50 mg per ml. For a reliable diagnostic visualization of portal vein contributaries and branches, a blood iodine concentration of 30 mg per ml appears required; whereas for the visualization of the larger portal vein, 15 mg per ml appears sufficient.