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Biomedical subjects

G M Gross

Publications and source records attributed to G M Gross.

11 recordsLinked to original sources
PubMed1992

Carotid endarterectomy monitored with transcranial Doppler.

Intraoperative transcranial Doppler monitoring of cerebral ischemia during carotid clamping under general anesthesia was done in 238 carotid artery operations, mostly endarterectomy. Depending on the severity of reduction of middle cerebral artery mean velocity, patients were classified as no, mild, or severe ischemia at clamping. With a carotid shunt, velocity was always in the "no ischemia" category during shunting. For patients with no ischemia, stroke was significantly lower without a shunt (2/175 no shunt versus 2/12 shunt). For mild ischemia, shunting did not affect the stroke rate (1/20 no shunt versus 0/9 shunt). For severe ischemia, strokes were less frequent with a shunt (4/9 no shunt versus 0/13 shunt). Intraoperative electroencephalogram predicted most, but not all severely ischemic cases. Carotid back pressure correlated with Doppler velocity, but transcranial Doppler was more helpful. Transcranial Doppler is a new and valuable technique in carotid surgery.

Aged↗
PubMed1991

Sequential 2D inflow venography: initial clinical observations.

Sequential 2D inflow NMR (SDI) venography was employed to define venous anatomy and pathology in five healthy subjects and five patients, mean age 48 +/- 7 years, with documented deep vein thrombosis. SDI images were graded independently by two observers on a scale of 1,2 nondiagnostic and 3,4 diagnostic categories. All iliac and femoropopliteal SDI venograms were diagnostic. In contrast, only one out of nine calf SDI venograms was diagnostic. SDI is a promising new method to assess the proximal peripheral venous system. Improved imaging strategy is needed to produce flow images of the calf veins.

Femoral Vein↗
PubMed1991

Urokinase infusion: feasibility of monitoring for complications in a non-intensive care setting.

In an effort to more effectively use critical care facilities and to reduce costs, during a 2 1/2-year period, the condition of 32 patients who received 37 local intraarterial urokinase (UK) infusions was monitored in a non-intensive care unit (ICU) setting. Techniques of infusion, mean total dose of lytic agent used (1.7 million IU), and mean duration of infusion (22 hours) were similar to those reported previously in series of patients monitored in the ICU. Complete lysis (no angiographically detectable residual clot within the treated segment) was achieved in 28 of 37 infusions (76%). Major complications occurred during two infusions (5.4%). In 33 of the 37 cases, systemic heparin was administered during UK infusion. No cases of pericatheter thrombosis were encountered. At the authors' institution, patients can be safely monitored during local UK infusion in a non-ICU setting without compromising effectiveness of therapy. This approach has resulted in enhanced cost-effectiveness of thrombolytic therapy and more effective use of critical care facilities.

Cost-Benefit Analysis↗
PubMed1991

Peripheral arterial occlusive disease: prospective comparison of MR angiography and color duplex US with conventional angiography.

Conventional angiography, two-dimensional inflow magnetic resonance (MR) angiography, and color duplex ultrasound (US) were performed on 12 patients in a blinded, prospective study. The ability to grade arterial lesions and plan revascularization interventions were compared. Arterial lesions were categorized as nonsignificant (0%-49% diameter reduction) or significant (50%-100% diameter reduction). Determination of nonsignificant and significant lesions with MR angiography was in agreement with that at conventional angiography in 100 of 140 lesions (71%). Agreement between results of conventional angiography and color duplex US occurred with 114 of 123 infrainguinal lesions (93%). Twenty-one vascular interventions were planned by using conventional angiography; there was agreement with color duplex US in 11 cases and MR angiography in five. Color duplex US performed well in the assessment of infrainguinal disease but was limited in the evaluation of iliac segments because of nonvisualization. The iliac region was visualized in more patients with MR angiography than with color duplex US, but image quality with MR angiography was inconsistent. Strategies to improve MR angiography of the peripheral vasculature merit further study.

Aged↗
PubMed1990

Transcatheter thrombosis of a leaking saccular aneurysm of the main renal artery with preservation of renal blood flow.

Percutaneous techniques have been used in the treatment of aneurysms and pseudoaneurysms in a variety of anatomic locations, including the kidney. An elderly patient with a leaking saccular aneurysm of the main left renal artery was considered a poor operative risk. We were able to embolize and thrombose the aneurysm selectively by using a combination of coil springs, guidewire, thrombin, and bucrylate without occluding the renal artery.

Aged↗
PubMed1989

Chronic arteriovenous fistulas masquerading as arteriovenous malformations: diagnostic considerations and therapeutic implications.

Arteriovenous fistulas (AVFs) and arteriovenous malformations (AVMs) may be difficult to differentiate angiographically, and this differentiation has important therapeutic implications. In five cases of chronic AVF, four originally misdiagnosed as AVMs, superselective angiography enabled the correct diagnosis. In two plantar arch fistulas, the technique was further enhanced by manual compression of arterial inflow to decrease the rate of blood flow through the fistula. All five AVFs were successfully occluded. The authors conclude that AVFs and AVMs can be distinguished by means of the appropriate angiographic techniques.

Adult↗
PubMed1988

Preoperative evaluation of abdominal aortic aneurysm by MR imaging with aortography correlation.

Sonography, computed tomography, and most recently, magnetic resonance imaging (MRI) have been advocated as noninvasive imaging methods for the preoperative evaluation of patients with abdominal aortic aneurysms (AAA). We prospectively assessed the value of MRI in this clinical setting. Twenty of 23 patients with AAA referred for evaluation with biplane aortography underwent MRI within 3 days of aortography. MR and angiographic studies were interpreted prospectively and independently and then the results were compared with each other and with the operative findings. All angiographically demonstrated infrarenal and suprarenal aneurysms except one were documented as such by MRI. The distal extent of the aneurysm on MRI agreed with that on angiography in all but 3 cases. MRI is an accurate method for assessing the size and extent of AAA and its relationship to the main renal artery origins. MRI is not accurate in detecting vascular obstructions or accessory renal arteries. Therefore, the usefulness of MRI and the need for aortography in preoperative assessment of AAA depends upon the specific information the surgeon requires prior to aneurysmectomy in a given patient.

Aorta, Abdominal↗
PubMed1986

31P nuclear magnetic resonance spectroscopy: noninvasive biochemical analysis of the ischemic extremity.

The biochemical effects of peripheral vascular disease on skeletal muscle have not been characterized precisely because of the lack of satisfactory noninvasive analytic methods. 31P nuclear magnetic resonance (NMR) spectroscopy was used to measure the high-energy phosphate compounds, phosphocreatine (PCr) and adenosine triphosphate, as well as metabolic byproducts, such as inorganic phosphates (Pi) and phosphate monoesters in calf muscles of 214 limbs with peripheral vascular disease. Intracellular pH was also measured. The NMR index (Pi[PCr + Pi]) was used to quantitate the impairment of oxidative phosphorylation as a result of ischemia. Studies done at rest documented the impairment of oxidative metabolism only in limbs with severe ischemia (ankle-brachial pressure index (API) less than 0.4). Exercise resulted in a significant elevation of the NMR index in all limbs and the rate of return of this value toward normal following exercise was prolonged even in limbs with moderate ischemia (0.4 less than or equal to API less than or equal to 0.9). Correlation of 31P NMR parameters with arteriograms showed that infrapopliteal occlusions resulted in prolonged recovery times only when the superficial femoral artery was occluded and emphasized the metabolic consequences of multisegmental disease. Accumulation of glycolytic pathway intermediates correlated with the decrease in muscle cell pH observed with exercise. Despite immediate improvement in symptoms and hemodynamic parameters following revascularization, return to normal biochemical function occurs over a prolonged period of time. This study demonstrates that 31P NMR spectroscopy can successfully measure noninvasively the important phosphorus-containing compounds involved in the bioenergetics of skeletal muscle in vivo rapidly enough to permit real-time determination during exercise and recovery.

Adenosine Triphosphatases↗