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G Papanicolaou

Publications and source records attributed to G Papanicolaou.

At least 19 recordsLinked to original sources
PubMed2004

Retrospective study of the hepatic safety profile of patients concomitantly treated with caspofungin and cyclosporin A.

BACKGROUND: Mild, transient alanine aminotransferase (ALT) elevations were seen in Phase I studies of caspofungin and cyclosporin A (CsA). METHODS: We conducted a retrospective chart review at four sites to characterize the hepatic safety in patients receiving > or =1 day of both drugs over a 20-month period. Investigators assessed reasons for discontinuing concomitant therapy and the presence/etiology of any hepatotoxicity. RESULTS: Forty patients receiving concomitant therapy for 1-290 days (median 17.5 days) were identified. Although common, liver enzyme abnormalities were frequently attributed to other comorbidities or medications. ALT and/or aspartate aminotransferase (AST) elevations occurred in 14 patients (35%). Five had AST elevations at least possibly related to caspofungin/CsA, but none were >3.6 times the normal upper limit. No ALT elevations were related to caspofungin/CsA. Two of 4 patients had discontinuation of therapy because of hepatotoxicity possibly related to caspofungin/CsA. No serious adverse events occurred because of caspofungin. CONCLUSIONS: These data do not suggest a significant risk of clinically relevant hepatotoxicity with concomitant caspofungin/CsA.

Adolescent↗
PubMed2001

Pneumocystis carinii pneumonia prophylaxis with atovaquone in trimethoprim-sulfamethoxazole-intolerant orthotopic liver transplant patients: a preliminary study.

Pneumocystis carinii pneumonia (PCP) is an opportunistic infection associated with increased morbidity and mortality in solid-organ and bone-marrow transplant recipients. Side effects of trimethoprim-sulfamethoxazole (TMP/SMX) are frequent; therefore, we performed a preliminary study using atovaquone suspension, 750 mg once daily, for 1 year for the prevention of PCP in liver transplant recipients intolerant to TMP/SMX therapy. Twenty-eight patients were treated, and data were analyzed for efficacy and toxicity. Adverse events occurred in 14 subjects, mainly related to the gastrointestinal tract. Side effects from TMP/SMX, i.e., rash, completely resolved and bone-marrow suppression improved in 62% of patients. No patients developed Pneumocystis carinii infection. Although a lower dose of atovaquone once daily may be effective in transplant recipients, further studies are necessary to confirm this preliminary observation. Liver Transpl 2001;7:750-751.)

Antifungal Agents↗
PubMed2001

Depolarization and blurring of optical images by biological tissue.

We present a study of the image blurring and depolarization resulting from the transmission of a narrow beam of light through a continuous random medium. We investigate the dependence of image quality degradation and of depolarization on optical thickness, correlation length of the inhomogeneities, and incident polarization state. This is done numerically with a Monte Carlo method based on a transport equation that takes into account polarization of light. We compare our results with those for transport in media with discrete spherical scatterers. We show that depolarization effects are different in these two models of biological tissue.

Lasers↗
PubMed1999

Combined use of iliac artery angioplasty and infrainguinal revascularization for treatment of multilevel atherosclerotic disease.

The purpose of this report is to review our recent experience with the combined use of iliac artery angioplasty and infrainguinal surgical revascularization for the treatment of multilevel atherosclerotic disease. A retrospective review of all patients with multilevel atherosclerotic disease who were treated with both iliac artery angioplasty and infrainguinal bypass surgery during a 4-year period was performed. The medical records and preoperative arteriograms of all patients were reviewed for demographic information, radiologic findings, and postoperative follow-up data. Ninety-three limbs in 87 patients were studied. There were 57 male and 30 female patients with an average age of 67.2 years (range: 38-90). We concluded that the combined use of iliac artery angioplasty and infrainguinal surgical revascularization is an effective and durable means of treating multilevel atherosclerotic disease.

Aged↗
PubMed1996

A prospective study of carbon dioxide-digital subtraction vs standard contrast arteriography in the evaluation of the renal arteries.

OBJECTIVE: To compare carbon dioxide-digital subtraction arteriographic (CO2-DSA) images of renal artery anatomy with standard iodinated contrast arteriographic (ICA) images. DESIGN: One hundred patients with vascular disease who required abdominal aortography were evaluated by both CO2-DSA and ICA modalities. Two blinded readers interpreted arteriograms for the degree of renal artery stenosis, and a third reader was employed to resolve differences in reader interpretations. SETTING: University medical center. MAIN OUTCOME MEASURES: The sensitivity, specificity, negative predictive value, positive predictive value, and accuracy were calculated for the ability of CO2-DSA to demonstrate a 60% or greater stenosis of the main renal artery; kappa values for CO2-DSA and ICA were calculated to assess intraobserver variability. RESULTS: Of the 200 main renal arteries imaged, 17 (9 by means of CO2-DSA), 8 means of ICA) were eliminated because of inadequate visualization of the renal artery. In identifying a renal artery stenosis of 60% or greater, CO2-DSA had a sensitivity of 0.83, specificity of 0.99, positive predictive value of 0.94, and negative predictive value of 0.98. The overall accuracy was 0.97. The kappa was 0.75 for CO2-DSA and 0.70 for ICA, hence, the variation in the interpretations of CO2-DSA and ICA were comparable. CONCLUSION: Images by means of CO2-DSA accurately reflect pathologic changes in renal arteries and are thus useful in the diagnosis of clinically occult occlusive renal artery disease in patients at risk of contrast medium-related nephrotoxicity.

Adult↗
PubMed1996

Penetrating trauma of the internal carotid artery.

OBJECTIVE: To assess management of penetrating internal carotid artery (ICA) injuries. DESIGN: Retrospective review of institutional protocol. SETTING: Level 1 trauma center in a major urban area. PATIENTS: Sixty-one patients with penetrating ICA injuries. INTERVENTIONS: In the period 1975 to 1987 (group 1; n = 36), management was based on individual surgeons' preferences. Between 1988 and 1995 (group 2; n = 25), an algorithm was employed: (1) hemodynamically stable patients with suspected ICA injuries underwent a diagnostic angiography; (2) surgically accessible injuries were reconstructed regardless of neurologic status with 2 exceptions: (a) neurologically intact patients with ICA occlusion were treated by anticoagulation and mild pharmacological hypertension and (b) minimal nonocclusive injuries were managed nonoperatively and followed up by serial angiography or duplex ultrasonography; and (3) heparinization, shunting, and completion angiography were employed. MAIN OUTCOME MEASURES: Neurologic status at admission and discharge were compared by the Fisher exact test. RESULTS: In group 1, 24 patients (67%) presented neurologically intact, and 12 (33%) with a deficit. Sixteen injuries were managed nonoperatively, 14 were repaired, and 6 were ligated. At discharge 6 (17%) were improved, 24 (66%) were unchanged, 6 (17%) were worse. Four patients (11%) died of cerebrovascular causes. In group 2, 19 patients (76%) presented neurologically intact, and 6 (24%) with a deficit. Eleven injuries were managed nonoperatively, 12 were repaired, and 2 were ligated. A death occurred in a patient who arrested, was admitted to the hospital in a coma, and died before ICA repair. CONCLUSIONS: Neurologic outcome after ICA injury is enhanced by an algorithm predicated on the liberal use of angiography, a predefined surgical approach, and selective observation.

Adolescent↗
PubMed1996

Cardiac evaluation of the diabetic patient prior to peripheral vascular surgery.

The benefit of preoperative cardiac evaluation in the diabetic patient undergoing peripheral vascular surgery is uncertain. To investigate this issue we performed a retrospective review of 192 procedures performed in diabetic patients for chronic lower extremity arterial occlusive disease. The incidence of adverse postoperative cardiac events was determined, as well as its association with several preoperative factors including symptoms of coronary artery disease (CAD), extent and results of preoperative noninvasive cardiac evaluation, and operative site (aorta vs. lower extremity). The overall death and cardiac complication rates were 10.2% for lower extremity and 25.7% for aortic procedures (p = 0.02). For myocardial infarction and cardiac death alone, the rates were 5.1% and 5.7%, respectively (p > 0.10). Although a history of symptomatic CAD predicted the occurrence of any cardiac complication (28.3% vs. 8.2% [p < 0.01] for the aortic and lower extremity revascularization groups combined), no factor was found to be associated with the occurrence of myocardial infarction and cardiac death alone. In patients with a history of symptomatic CAD, there was no significant difference in the incidence of complications whether or not preoperative noninvasive cardiac testing was performed (28.1% vs. 28.6%, p > 0.10) or, if testing was performed, if the results were abnormal or normal (35.3% vs. 20.0%, p > 0.10). Similar results were obtained in patients with no history of symptomatic CAD. In summary, this retrospective review of our experience with noninvasive evaluation to detect CAD in diabetic patients undergoing peripheral vascular surgery failed to show any benefit in terms of reducing the incidence of postoperative cardiac events.

Aged↗
PubMed1996

Intraoperative color duplex scanning for infrainguinal vein grafts.

We compared the findings of intraoperative color duplex scanning and completion arteriography in patients undergoing infrainguinal vein bypasses to identify hemodynamic abnormalities that could result in a predisposition to early or late graft failure. We reviewed the records of 72 patients who underwent 81 vein bypass graft procedures. Three intraoperative diagnostic methods were used. In 28 procedures (group I) both color duplex and completion arteriography were used, in 21 procedures (group II) only color duplex was used, and in 26 procedures (group III) only completion arteriography was used. Grafts were followed using a duplex surveillance protocol for a mean interval of 16.1 months. Nine grafts in group I showed an abnormality on the duplex scan but not on the completion arteriogram. Seven grafts had a peak systolic velocity (PSV) greater than 200 cm/sec and two had a PSV less than 45 cm/sec. These findings led to six immediate repairs, one early revision, and two late revisions. Arteriography demonstrated additional defects in two procedures but repairs were not performed. In group II duplex scans showed an abnormality in eight procedures (seven grafts with PSV 200 to 250 cm/sec and one graft with a retained valve) resulting in three immediate repairs and five late revisions. In the remaining 13 procedures in group II, duplex scans were normal and no revisions were required during follow-up. In group III defects were detected by arteriography in four procedures (> 50% stenosis in three grafts and one arterial spasm) leading to three immediate repairs. In the remaining 22 studies arteriograms were interpreted as normal; however, seven of these grafts required late revisions. Our data suggest that grafts that appear normal on intraoperative duplex scans are not likely to develop a stenosis requiring revision. Intraoperative duplex ultrasound may be superior to completion arteriography.

Adult↗
PubMed1996

Difficult peripheral vascular injuries.

Successful management of the difficult peripheral vascular injury requires a multidisciplinary approach. Prompt recognition of the vascular injury and adherence to the recognized principles of vascular repair provide a successful short-term surgical result. The long-term consequences of an injury are determined by the associated orthopedic, soft tissue, and nerve injuries.

Algorithms↗
PubMed1996

Surgical revascularization versus thrombolysis for nonembolic lower extremity native artery occlusions: results of a prospective randomized trial. The STILE Investigators. Surgery versus Thrombolysis for Ischemia of the Lower Extremity.

PURPOSE: Early results of a prospective study that compared surgical revascularization and thrombolysis for lower extremity arterial and graft occlusions have been published. This report details the final results in patients who have native artery occlusions. METHODS: Two hundred thirty-seven patients who had lower extremity ischemia as a result of iliac-common femoral (IF; 69 patients) or superficial femoral-popliteal (FP; 168 patients) occlusion, and had symptomatically deteriorated within the past 6 months were randomized to catheter-directed thrombolysis (150 patients) or surgical revascularization (87 patients). After diagnostic arteriographic examination but before randomization, the optimal surgical procedure was determined. Lytic patients were randomized to recombinant tissue plasminogen activator (rt-PA; 84 patients) or urokinase (UK; 66 patients). Recurrent ischemia, morbidity, amputation, and death rates were determined at 30 days, 6 months, and 1 year, and were analyzed on an intent-to-treat basis. RESULTS: For patients randomized to lysis, a catheter was properly positioned and the lytic agent delivered in 78%. This provided a reduction in the predetermined surgical procedure in 58% of patients who had an FP occlusion and 51% of those who had an IF occlusion. rt-PA and UK were equally effective and safe, but lysis time was shorter with rt-PA (8 vs 24 hr; p < 0.05). At 1 year, the incidence of recurrent ischemia (64% vs 35%; p < 0.0001) and major amputation (10% vs 0%; p = 0.0024) was increased in patients who were randomized to lysis. Factors associated with a poor lytic outcome included FP occlusion, diabetes, and critical ischemia. No differences in mortality rates were observed at 1 year between the lysis and surgical groups. CONCLUSION: Surgical revascularization for lower extremity native artery occlusions is more effective and durable than thrombolysis. Thrombolysis used initially provides a reduction in the surgical procedure for a majority of patients; however, long-term outcome is inferior, particularly for patients who have an FP occlusion, diabetes, or critical ischemia.

Arterial Occlusive Diseases↗
PubMed1996

Relationship between intraoperative color-flow duplex findings and early restenosis after carotid endarterectomy: a preliminary report.

PURPOSE: This study was undertaken to examine the relationship between intraoperative color-flow duplex (CFD) findings and the development of restenosis in patients undergoing carotid endarterectomy (CEA). METHODS: Seventy-eight patients (43 male and 35 female; mean age, 65 years) underwent 86 CEAs (eight staged bilateral) and intraoperative CFD during a 31-month period. Three patients (three CEAs, 3%) underwent both CFD and a completion arteriographic scan. Patients were observed in a postoperative protocol using CFD surveillance. The follow-up interval ranged from 6 to 24 months (average, 12 months). RESULTS: After undergoing CEA, 10 patients (10 CEAs, 11%) had an abnormality detected by intraoperative CFD; one was confirmed with a completion arteriographic scan. These abnormalities consisted of elevated peak systolic velocities (PSV) with a mosaic color pattern suggesting turbulence seen in six CEAs, including one internal carotid artery (ICA) with abnormal hemodynamics and an unremarkable completion arteriogram. Intimal defects on B-mode were seen in another four CEAs. These carotid arteries were reexplored, defects (intimal flaps with platelet thrombus) were confirmed by direct examination, and all were repaired with or without a patch (six ICAs, three external carotid arteries, and one common carotid artery). No cerebrovascular events occurred in the perioperative period. No carotid restenosis (> or = 50% diameter reduction) was identified during follow-up of 43 patients (48 CEAs, 56%). Two patients had recurrent neurologic symptoms. CONCLUSION: Intraoperative CFD is an effective test for detecting flow abnormalities or intimal defects in patients undergoing CEA. Ensuring normal intraoperative hemodynamics after CEA may be a major factor associated with decreased incidence of perioperative cerebrovascular events and subsequent carotid artery restenosis.

Adult↗
PubMed1996

Systolic flow limitation in stenotic lower-extremity vein grafts.

PURPOSE: Our purpose was to investigate the hemodynamic theory that the blood flow rate through a stenotic arterial graft is limited by the onset of turbulence, which acts as a barrier at peak systole against further increases in systolic flow. METHODS: We used duplex ultrasonography to examine 25 stenotic infrainguinal vein grafts. Theory predicts that the flow limitation occurs at peak systole at a stenotic velocity greater than 250 cm/sec, which corresponds to a residual stenotic lumenal diameter of 0.36 cm (Reynolds No. 2000). These numbers are based on the assumption that the 68 ml/min blood flow is supplied by the femoropopliteal graft to the resting lower leg only during systole. When the lumen is smaller than 0.36, peak systolic velocity (PSV) must exceed 250 cm/sec. The increased velocity results in poststenotic turbulence. This turbulent condition restricts the average graft systolic flow to less than the 68 ml/min required by the lower leg, so diastolic flow is needed to make up the deficit. RESULTS: Twenty vein grafts with PSVs of 250 cm/sec or greater had end-diastolic velocities of 50 cm/sec or greater as predicted; three grafts with PSVs of 256 to 300 cm/sec and two grafts with PSVs of less than 250 cm/sec had no forward diastolic flow. CONCLUSION: The onset of turbulence in a stenotic vein graft supplying the lower leg occurs at a PSV of 250 cm/sec or greater. The appearance of diastolic flow maintains the average graft volume flow.

Blood Flow Velocity↗
PubMed1996

A recent institutional experience with renovascular hypertension.

During and 8-year period, 51 patients with renovascular hypertension were evaluated. Etiologies of renovascular disease included atherosclerosis 29 (57%), Takayasu's arteritis 11(22%), fibromuscular dysplasia six (11%), renal artery dissection two (4%), trauma two(4%¿ and aneurysm one (2%). Fifteen (29%) patients had bilateral renal artery disease, and 16 (31%) had associated chronic renal failure. Seven patients initially underwent percutaneous transluminal angioplasty, three of whom later required operative intervention for recurrent hypertension, and one required repeat angioplasty. Three patients had no further intervention. Forty-seven patients underwent surgical revascularization tailored to the angiographic and intraoperative findings. Procedures performed included 36 (55%) aortorenal bypasses; 12 (18%) endarterectomies; five (8%) ex-vivo reconstructions; three (4%) renal artery reimplantations; two (3%) other visceral artery-to renal (hepatic/splenic) reconstructions; one (2%) renal artery patch graft; and seven (10%) nephrectomies. Concomitant aortic replacement occurred in 20 cases. There were two deaths, and remedial operations for recurrent hypertension were required in three patients. The mean follow up was 12 months (range 6-45 months). Hypertension was cured in 25 (57%), improved in 14(32%), and unchanged in five (11%). Of the 16 patients with chronic renal failure, eight (50%) had a reduction in serum creatinine >10%. The etiology of renovascular hypertension is variable. Although transluminal angioplasty may be indicated in selected patients, surgical revascularization is usually necessary. A flexible operative approach to accommodate the variable patterns of renal artery disease optimizes surgical results. Renal revascularization may provide and improvement in excretory renal function.

Adolescent↗
PubMed1995

The relationship between arm-ankle pressure difference and peak systolic velocity in patients with stenotic lower extremity vein grafts.

The relationship between the measured arm-ankle pressure difference (AAPD), or the ankle/arm index (AAI), and the focal peak systolic velocity (PSV) at stenotic sites of infrainguinal vein grafts has not been determined. We attempted to relate these two parameters. We used Doppler systolic pressures and duplex ultrasonography to study 35 infrainguinal vein bypass grafts followed in a surveillance protocol. The following graft groups were identified: grafts in nondiabetic patients (n = 26), grafts in diabetic patients (n = 9), nonrevised stenotic grafts (n = 14), revised stenotic grafts (n = 14), and normal grafts (n = 7). AAPD and AAI were measured in both lower extremities. Pressure gradients across graft stenoses were indirectly estimated using the modified Bernoulli equation (delta P =4V2). Measured AAPDs and estimated pressure gradients showed moderate correlation in nondiabetic (r = 0.58) and diabetic (r = 0.63) patients. Correlation was fair (r = 0.3) prior to graft revision. There was no correlation (r = 0.1) in the nonrevised stenotic grafts. For individual patients with stenotic grafts who were followed in consecutive visits, the correlation varied from none to good (r range 0.01 to 0.71). We conclude that there is a lack of consistent correlation between the measured AAPD, or AAI, and the estimated stenotic graft pressure gradient. This finding illustrates the limitation of the AAI as a monitoring test to predict failure of stenotic infrainguinal vein grafts.

Ankle↗
PubMed1995

Hemodynamics of stenotic infrainguinal vein grafts: theoretic considerations.

We developed a theoretic model of arterial stenosis to study the relationship between perfusion pressure and regional hemodynamics in stenotic infrainguinal vein grafts in an attempt to identify grafts at high risk for failure. Our model was based on the concept of energy and mass conservation of the flowing blood. We used the modified Bernoulli equation (delta P = 4 delta V2) to calculate the maximum possible intrastenotic peak systolic velocity (PSV) from the systolic blood pressure. PSV was measured by means of duplex ultrasonography in infrainguinal bypasses up to the time of revision (nine grafts) or spontaneous thrombosis (two grafts). We related arm systolic blood pressure, intrastenotic PSV, and prestenotic PSV obtained from duplex examinations conducted prior to graft thrombosis or revision and applied our model to these stenotic vein grafts. Intrastenotic PSV was consistently lower than maximum PSV predicted from the Bernoulli equation. The highest measured intrastenotic PSV of 600 cm/sec would require a minimum perfusion pressure of 144 mm Hg. The lowest measured PSV (20 cm/sec) was considered the minimum "thrombotic threshold velocity." This model predicts that for parabolic profile flow in an 80% diameter-reducing axisymmetric stenosis (96% cross-sectional area reduction), a prestenotic PSV of 20 cm/sec would produce an intrastenotic PSV of 500 cm/sec requiring the equivalent potential energy of 100 mm Hg systolic blood pressure. Our theory implies that in patients with nocturnal hypotension thrombosis of stenotic vein grafts may occur.

Blood Flow Velocity↗
PubMed1995

Carbon dioxide/digital subtraction arteriography-assisted transluminal angioplasty.

During a 62-month period, carbon dioxide was used to supplement or completely replace iodinated contrast agents in performing 27 transluminal angioplasties in 26 patients. The arterial segments addressed included the following: renal in two cases, iliac in five, femoral/popliteal in 15, infrapopliteal in two, and combined in three. Indications for intervention included lower extremity gangrene in 11 cases, ischemic ulceration in 10, rest pain in three, claudication in one, and ischemic nephropathy in two. Contraindications to iodinated contrast agents included renal insufficiency resulting from diabetes (n = 20) or ischemic nephropathy (n = 2) and congestive heart failure (n = 4). Eight procedures used carbon dioxide as the sole contrast agent, whereas 19 required supplementation of carbon dioxide with a mean of 39 ml of nonionic contrast medium. Technical success was achieved in 25 procedures with significant hemodynamic improvement in 20 patients. Complications included transient deterioration in renal function in two patients and myocardial infarctions in two. At 30 days 18 patients had demonstrated significant clinical improvement. Patients at high risk for iodinated contrast-related complications may undergo transluminal angioplasty using carbon dioxide/digital subtraction arteriography to reduce or eliminate the need for iodinated contrast agents.

Adult↗