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Biomedical subjects

D C Levin

Publications and source records attributed to D C Levin.

At least 127 records · Page 7Linked to original sources
PubMed1982

New equipment considerations for angiograhic laboratories.

The modern angiographic laboratory should be equipped to perform peripheral, visceral, and interventional procedures. Biplane, magnification, multiangulation, and spot filming capabilities are all desirable. Power requirements have decreased in recent years as a result of the introduction of rare earth screen-film systems and the incorporation of carbon fiber into tabletops and film changer faceplates. As a result, generators with lower power outputs and x-ray tubes with smaller focal spots can be used. Multiangulation rotational mounting units have been developed in recent years by the major equipment manufacturers; these units have major advantages over older ones, but their designs incorporate certain drawbacks with which angiographers should be familiar.

Angiography↗
PubMed1982

Flexible fiberoptic bronchoscopy and fluoroscopically guided transbronchial biopsy in the management of solitary pulmonary nodules.

In our experience with fluoroscopically guided flexible fiberoptic bronchoscopy (FFB), transbronchial biopsy, bronchial brush, bronchial washing (BW) and sputum cytology (SC) in 101 patients with solitary pulmonary nodules (SPN) less than 6 cm in diameter (without endobronchial tumor), a specific diagnosis was reached via FFB in 36 cases. The diagnostic yields in primary lung malignant lesions (PLM), metastatic lesions and benign SPN were 58 percent, 28 percent and 10 percent, respectively. Size affected diagnostic efficiency considerably, with a 12 percent yield in lesions under 2 cm, a 40 percent yield in lesions 2 to 4 cm and a 63 percent yield in lesions over 4 cm. BW and SC (prebronchoscopic) did not contribute enough information to justify their cost. FFB directly affected therapy in 17 patients who were not thoracotomy candidates and may have influenced the decision for surgical treatment in another 19 patients diagnosed as having PLM. In 65 patients results of FFB were negative and the procedure did not appear to directly affect subsequent management because malignancy was not ruled out.

Adult↗
PubMed1982

Invasive evaluation (coronary arteriography) of the coronary artery disease patient: clinical, economic and social issues.

Radionuclide techniques have greatly enhanced noninvasive evaluation in the patient with suspected coronary artery disease (CAD). Although these techniques have high sensitivity and specificity, the published data contain significant inconsistencies and inaccuracies. Coronary arteriography remains the definitive method of determining the presence, site, severity and operability of CAD. Although the procedure is invasive, recent studies have shown that complication rates have been reduced to an acceptably low level, particularly in laboratories with extensive experience. The economic aspects of coronary arteriography are complex. Survey data acquired in early 1981 from 54 active cardiac catheterization laboratories around the country showed that the mean technical charge billed by the hospital for coronary angiographic procedures was $760 (range $307-1470). Analysis of the actual costs of the procedure to the hospital indicates that in most cases, these costs far exceed $760. Hospital budgeting practices in many states fail to create any incentive to match charges with costs. The mean professional fee billed by physicians for coronary arteriography was $640 (range $200-1200). An estimated 275,000 coronary arteriograms are performed annually in the United States, yielding a total cost of $577,500,000. Opportunities for significant cost cutting are limited, and seem to lie primarily in improving the utilization of existing laboratories that are underutilized. Unresolved economic, ethical and social issues pertaining to coronary arteriography include: centralizing the procedure in a smaller number of centers around the country; self-referral of patients for coronary arteriography; establishing training standards for coronary angiographers and performance standards for angiographic equipment; acceptable levels of sensitivity in noninvasive screening for suspected CAD; and utilization of coronary arteriography throughout the country.

Angiography↗
PubMed1981

The effect of sequential arterial stenoses on flow and pressure.

The additive effect of two sequential stenoses on arterial flow and pressure was studied in five dogs, using an extracorporeal aorto-femoral shunt. It was determined that the concept of flow being governed by the more severe stenosis is imprecise. This is true only of one critical and one subcritical lesion: two critical stenoses have an additive effect. Otherwise subcritical stenoses can become critical in the presence of hyperemia. When evaluating patients with vascular insufficiency due to arterial narrowing, all stenoses should be carefully assessed and attention directed to their cumulative effect.

Animals↗
PubMed1981

The effect of coronary artery bypass on collateral circulation.

The effect of coronary bypass upon collateral circulation (CC) was studied in 69 bypassed coronary arteries in which CC was seen on either the preoperative or postoperative angiogram or both. CC proved to be a highly reliable indicator of bypass effectiveness. Persistence or new development of CC on postoperative angiograms invariably indicated complete bypass obstruction or inadequate revascularization. Disappearance of preexisting CC on postoperative angiograms almost always indicated bypass patency. Occlusion of a bypass does not appear to jeopardize preexisting CC or prevent new CC from developing in most cases.

Adult↗
PubMed1981

Frequency and clinical significance of failure to visualize the conus artery during coronary arteriography.

In patients with occlusion of the left anterior descending coronary artery (LAD) or right coronary artery (RCA), the conus artery, which arises at or near the origin of the RCA, often serves as a principal source of collateral circulation. Coronary arteriograms in 508 adult patients revealed that in 80.5% the conus artery was well visualized on the RCA angiogram, but that in 19.5% it was not adequately visualized due to injection of contrast distal to its origin. In the latter patients, the presence of conus-LAD or conus-RCA collaterals might therefore go undetected. Because the degree of distal filling via collateral circulation affects medical and surgical decisions, it is important to attempt to visualize the conus artery adequately whenever the LAD or RCA is obstructed.

Angiography↗
PubMed1981

Therapeutic embolization of the gastroduodenal artery in hepatic artery infusion chemotherapy.

Transcatheter embolization of the gastroduodenal artery with Gelfoam was performed in 12 patients undergoing percutaneous hepatic artery catheterization for infusion chemotherapy of metastatic liver disease. The purpose of the embolization was to prevent chemotherapeutic drugs from reaching the stomach and duodenum and thereby inducing gastrointestinal toxicity in patients in whom the catheter tip could not be satisfactorily positioned beyond the gastroduodenal origin. Embolization proved safe and effective in eight cases. Three other patients experienced clinical problems that may or may not have been related to embolization. The final patient had a significant complication (necrosis of the pancreatic head and gastric mucosa) that was felt to be directly related to the embolization. Transcatheter gastroduodenal occlusion may help reduce gastrointestinal toxicity of intraarterial infusion chemotherapy. However, it may on occasion be associated with significant complications, particularly in patients who are debilitated due to metastatic disease.

Adult↗
PubMed1980

Renal hemangioma: diagnostic aspects and management techniques.

Renal hemangiomas are rare lesions that demonstrate a spectrum of clinical, radiographic, and pathologic presentation. Angiographic differentiation from renal cell carcinoma is usually possible, and in such cases conservative management should be attempted. Hemangiomas are in some ways similar to arteriovenous malformations, but lack the rapid and pronounced pre-capillary shunting that characterize the latter. Three cases are presented, two managed surgically with one requiring nephroscopy for diagnosis, and one managed non-operatively. Brush biopsies of lesions with pyelographic characteristics of renal hemangioma should not be attempted without prior angiography.

Adult↗
PubMed1980

The changing role of pancreatic arteriography in the era of computed tomography.

Computed tomography (CT) in the assessment of suspected pancreatic disease, although an excellent screening procedure, has certain shortcomings, such as a significant percentage of inaccurate studies, a low predictive value of the finding of a pancreatic mass, failure to detect small lesions, and inability to differentiate localized masses caused by pancreatitis from those caused by adenocarcinoma. Arteriography provides important additional information in patients with clinically suspected pancreatic lesions and positive findings on CT or other noninvasive screening studies in whom surgical resection is contemplated. This procedure helps determine the presence and resectability of adenocarcinoma and can also demonstrate lesions which may resemble pancreatic adenocarcinoma on CT but which, in reality, are nonmalignant or nonpancreatic or both. Arteriography should no longer be used as a screening procedure but should be performed whenever a potentially resectable pancreatic mass, either cystic or solid is suggested by CT.

Aneurysm↗
PubMed1980

Experimental determination of flow patterns of gelfoam emboli: safety implications.

A major potential hazard of therapeutic occlusion of arteries by selectively injected Gelfoam pledgets is inadvertent reflux of nonopaque emboli into the aorta with resultant occlusion of other vessels. A simple method of injecting Gelfoam emboli through the standard nonoccluding arterial catheters customarily used for diagnostic arteriography was experimentally tested. The method incorporated certain safety features such as introduction of one embolus at a time using tuberculin syringes, low pressure injection technique, and frequent test injections of contrast to ascertain vessel patency. The results indicate that Gelfoam emboli can be safely and reliably employed using this technique, provided the catheter tip is properly positioned and emboli are only introduced as long as contrast test injections demonstrate rapid antegrade flow and continued patency of the artery. Once stasis or occlusion of most major branches are detected, blood flow in the catheterized artery has effectively ceased and further embolization is risky.

Animals↗
PubMed1979

Left heart catheterization and angiography via the percutaneous femoral approach using an arterial sheath.

An arterial sheath with a proximal hemostasis valve and a side-arm extension tube was used in 562 consecutive patients undergoing cardiac catheterization and angiography via the femoral approach. Serious complications were rare. There was one death, one peripheral embolism, and one episode of delayed groin hemorrhage. The incidence of minor complications, including hematoma formation, in this series compares favorably with our own and the reported experience of others using the conventional percutaneous femoral approach. The sheath technique facilitated catheter exchanges and reduced patient discomfort. In addition, femoral artery pressure could be monitored via the side arm of the sheath during the catheterization. This proved helpful during retrograde catheterization of patients with aortic stenosis, as well as in detection of damping of coronary artery catheter tip pressure during coronary arteriography and hypotension following left ventriculography. Based upon this experience, use of an arterial sheath has become our standard practice when left heart catheterization is performed via the femoral approach, and the use of several different catheters is anticipated.

Aged↗
PubMed1979

Cinefluoroscopy in evaluating left ventricular contractility and aneurysms.

Cardiac cinefluoroscopy was performed immediately prior to biplane left ventriculography in 113 patients and the findings of two independent observers compared to the angiographically documented state of the left ventricle. The observers' interpretations were correct in 44% and 46% of studies, respectively; there were 41% and 24% false negatives and 24% and 29% false positives. The observers agreed in only 59% of cases. The results show that cinefluoroscopy for evaluation of left ventricular contractility is grossly inaccurate and should not be performed.

Cineradiography↗