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Biomedical subjects

C J White

Publications and source records attributed to C J White.

At least 73 records · Page 4Linked to original sources
PubMed1995

Coronary angioscopy.

Coronary angioscopy will not replace angiography as the gold standard for imaging atherosclerotic coronary arteries. However, there may well be a clinical niche for a technology that gives accurate information regarding a specific lesion, if that information can be used to improve the acute or chronic outcome of an interventional procedure. Our experience demonstrates that angioscopy indeed provides this information. Using angioscopy, we now have access to information regarding arterial wall disease that heretofore has been available only at necropsy. In addition, whereas angiography has provided only a 2-dimensional, gray-scale image of the coronary vessels, angioscopy offers a full-color, 3-dimensional perspective of the intracoronary surface morphology. These important lesion-specific details, not reliably available from angiography alone, may ultimately be used to improve patient outcome and to assess risk.

Angioplasty, Balloon, Coronary↗
PubMed1994

Cardiac allograft vasculopathy assessed by intravascular ultrasonography and nonimmunologic risk factors.

The genesis of cardiac allograft vasculopathy has been linked to nonimmunologic endothelial injury. Studies evaluating the role of nonimmunologic risk factors have thus far been limited to angiographic assessment. Intravascular ultrasound can detect cardiac allograft vasculopathy before it becomes angiographically evident. To assess the influence of nonimmunologic risk factors in the development of cardiac allograft vasculopathy, we studied 101 consecutive cardiac transplant recipients who underwent intracoronary ultrasound imaging during routine, annual coronary angiography. Based on the severity of intimal thickening, patients were divided into 2 groups: group 1 = minimal, mild, or moderate intimal thickness; and group 2 = severe intimal thickness. Cardiac transplant recipients with severe intimal thickness had higher levels of total cholesterol (267 +/- 70 vs 227 +/- 41 mg/dl, p = 0.0008), low-density lipoprotein cholesterol (187 +/- 47 vs 139 +/- 31 mg/dl, p = 0.0001), and triglycerides (237 +/- 75 vs 182 +/- 88 mg/dl, p = 0.0004), a higher percentage of weight gain (12 +/- 4% vs 8 +/- 5%, p = 0.0001), a larger body mass index (30 +/- 4 vs 25 +/- 3, p = 0.0001), and older donor age (27 +/- 5 vs 23 +/- 7 years, p = 0.005) than recipients with mild or moderate intimal thickness. Multiple regression analysis established that total cholesterol, low-density lipoprotein cholesterol, triglyceride levels, obesity indexes, donor age, and years following cardiac transplantation (p < 0.01) were independent predictors of the severity of intimal thickening, and thus the severity of cardiac allograft vasculopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Predictors of restenosis: a morphometric and quantitative evaluation by intravascular ultrasound.

Despite advances in catheter-based interventional techniques, restenosis remains a major complication of angioplasty. Recently, intravascular ultrasound imaging (IVUS) has provided new insight into plaque composition and geometric distribution inside the vessel. To investigate if IVUS-defined parameters can predict restenosis in patients after coronary angioplasty, we performed IVUS in 33 patients (33 lesions) after balloon angioplasty (n = 25) or directional atherectomy (n = 8). Qualitative analysis included assessment of plaque composition, plaque eccentricity, plaque fracture, and presence of dissection. In addition, minimal luminal diameter, percent diameter stenosis, percent area stenosis, plaque burden, and elastic recoil were quantitatively analyzed. Follow-up data were obtained 1, 2, and 6 months after angioplasty and were available for 30 patients. Angiographic restenosis occurred in 11 patients (group 1), and no restenosis occurred in 19 patients (group 2) by clinical (n = 10) or angiographic (n = 9) assessment. Plaque fracture was noted in 30% of group 1 patients and 74% of group 2 patients (p = 0.04). Major dissections were more frequent in group I than in group II (78% vs 10%, p = 0.009). Of the quantitative parameters analyzed, plaque burden was significantly higher in group 1 than in group 2 (0.50 +/- 0.05 vs 0.34 +/- 0.05, p = 0.0001). In 78% of the patients with plaque burden of > 0.40, restenosis developed. Thus, of the various parameters analyzed, the absence of plaque fracture, the existence of a major dissection, and greater plaque burden were associated with increased incidence of restenosis. Our results indicate that IVUS can identify a subset of patients in whom restenosis is likely to develop. Information about the morphologic features of the atheroma and its composition may be used to modify the interventional strategy and thus optimize lumen size and possibly reduce the chance of restenosis.

Aged↗
PubMed1994

Immune responses of elderly persons 4 years after receiving a live attenuated varicella vaccine.

Annually, for 4 years after a live attenuated varicella-zoster virus (VZV) vaccine was administered to 202 elderly (55 to > 87 years old) VZV-immune persons, the immune response of vaccinees was evaluated. Anti-VZV antibody levels were enhanced by vaccination for just 1 year. However, VZV-specific proliferating T cells in peripheral blood were increased in frequency from 1 in 68,000 to 1 in 40,000 at 1 year; VZV-responding T cells were still 1 in 51,000 4 years after vaccination. The calculated half-life of this enhanced immunity was 54 months. Age had little effect on response to the vaccine, but larger doses were associated with longer duration of enhanced immunity. Immunity in approximately 10%-15% of vaccinees, independent of dose, failed to increase with the vaccine. This might complicate the use of this vaccine for prevention or attenuation of herpes zoster in the elderly.

Age Factors↗
PubMed1994

Use of aortic counterpulsation to improve sustained coronary artery patency during acute myocardial infarction. Results of a randomized trial. The Randomized IABP Study Group.

BACKGROUND: Aortic counterpulsation has been observed to reduce the rate of reocclusion of the infarct-related artery after patency has been restored during acute myocardial infarction in observational studies. To evaluate the benefit-to-risk ratio of aortic counterpulsation during the early phase of myocardial infarction, a multicenter randomized clinical trial was performed. METHODS AND RESULTS: Patients who had patency restored during acute cardiac catheterization within the first 24 hours of onset of myocardial infarction were randomly assigned to aortic counterpulsation for 48 hours versus standard care. Intravenous heparin was used similarly in both groups and was continued for a median (25th, 75th percentile) of 5 (2,7) days. A total of 182 patients were enrolled; 96 were assigned to aortic counterpulsation and 86 to standard care. Repeat cardiac catheterization was performed at a median of 5 (4,6) days after randomization in 89% of patients assigned to aortic counterpulsation and in 90% of control patients. Patients randomized to aortic counterpulsation had similar rates of severe bleeding complications (2% versus 1%), number of units of blood transfused (mean, 1.3 +/- 2.6 versus 0.9 +/- 1.8 units), and vascular repair or thrombectomy (5% versus 2%) compared with patients treated in a conventional manner. Patients randomized to aortic counterpulsation had significantly less reocclusion of the infarct-related artery during follow-up compared with control patients (8% versus 21%, P < .03). In addition, there was a significantly lower event rate in patients assigned to aortic counterpulsation in terms of a composite clinical end point (death, stroke, reinfarction, need for emergency revascularization with angioplasty or bypass surgery, or recurrent ischemia): 13% versus 24%, P < .04. CONCLUSIONS: This randomized trial showed that careful use of prophylactic aortic counterpulsation can prevent reocclusion of the infarct-related artery and improve overall clinical outcome in patients undergoing acute cardiac catheterization during myocardial infarction.

Angioplasty, Balloon, Coronary↗
PubMed1994

Wiktor coronary stent.

The Wiktor stent is a unique balloon-expandable tantalum coil stent currently undergoing clinical trials to determine the efficacy and safety of the device for reducing restenosis and for salvaging a failed angioplasty (bailout). This article discusses the stent in detail, the procedure, possible complications, and its advantages and disadvantages.

Angioplasty, Balloon, Coronary↗
PubMed1994

Influence of donor and recipient gender on cardiac allograft vasculopathy. An intravascular ultrasound study.

BACKGROUND: Cardiac allograft vasculopathy remains the leading limitation to long-term survival after cardiac transplantation. While the influence of donor and recipient gender in the pathogenesis of cardiac vasculopathy is still poorly understood, studies have indicated that female allografts may be at higher risk for the development of cardiac allograft vasculopathy. The purpose of this study was to characterize the influence of donor and recipient gender on the early genesis of cardiac allograft vasculopathy by using intravascular ultrasound. METHODS AND RESULTS: Thirty-six consecutive cardiac transplant recipients were divided into three groups on the basis of donor and recipient gender as follows: group 1, female donor and male recipient (n = 8); group 2, male donor and female recipient (n = 7); and group 3, male donor and male recipient (n = 21). The three groups were similar with regard to donor and recipient age, weight, body surface area, serum lipids, left ventricular function, histocompatibility, cellular and vascular rejection, and cytomegalovirus infection. To precisely quantitate the extent of cardiac allograft vasculopathy, intravascular ultrasound was performed in all patients at the time of first annual angiography. Intimal thickening and intimal index were accurately quantitated by intravascular ultrasound. Intimal thickening was significantly greater in group 1 (0.55 +/- 0.15 mm) than in group 2 (0.18 +/- 0.04 mm) or group 3 (0.29 +/- 0.05 mm) (P < .05). In addition, the intimal index was greater in group 1 (0.20 +/- 0.04) than in group 2 (0.07 +/- 0.02) or group 3 (0.15 +/- 0.02) (P < .01, group 1 versus group 2). CONCLUSIONS: Male recipients of female allografts have a higher degree of vascular intimal hyperplasia detected by intravascular ultrasound at 1 year after heart transplantation. These findings indicate that donor and recipient gender influences the early genesis of cardiac allograft vasculopathy.

Age Factors↗
PubMed1993

Assessment of intracoronary morphology in cardiac transplant recipients by angioscopy and intravascular ultrasound.

Percutaneous coronary angioscopy and intravascular ultrasound are sensitive intravascular imaging methods for detecting early changes in coronary morphology in cardiac transplant recipients. To compare the 2 imaging modalities, 29 consecutive cardiac transplant recipients underwent percutaneous coronary angioscopy and intravascular ultrasound during annual coronary angiography. Surface morphology, presence of plaque, and percent area stenosis were determined with each procedure. Percutaneous coronary angioscopy was more sensitive in detecting the presence of plaque and stenosis than was coronary angiography (plaque: 79 vs 10% [p < 0.001]; and stenosis: 24 vs 3% [p < 0.01]). Intravascular ultrasound was also more sensitive in detecting plaque (76 vs 10%; p < 0.001) and stenosis (45 vs 3%; p < 0.001) than was coronary angiography. Although both angioscopy and ultrasound identified atherosclerotic plaque, only percutaneous coronary angioscopy could show luminal surface morphology and pigmentation of the plaque. Conversely, ultrasound could detect calcification and presence of intimal thickening, and was more accurate in assessing the severity of stenosis (45 vs 24%; p < 0.01). In conclusion, percutaneous coronary angioscopy and intravascular ultrasound, in conjunction, provide information not only regarding the appearance of the luminal surface, but also quantitative information regarding the structure and extent of the disease in the coronary artery wall.

Adult↗
PubMed1993

Partial congenital defect of the left pericardium: angiographic diagnosis and treatment by thoracoscopic pericardiectomy: case report.

Congenital defects of the pericardium are extremely rare and frequently difficult to diagnose. We present a diagnosis of partial congenital defect of the left pericardium based on a characteristic chest X-ray and left ventriculogram. Additionally, we report findings of a diastolic, migratory coronary stenosis on coronary arteriography which, to date, has not been reported. Confirmation of the diagnosis by mediastinoscopy was followed by thoracoscopic pericardiectomy.

Adult↗
PubMed1993

Placement of "biliary" stents in saphenous vein coronary bypass grafts.

Angioplasty of coronary saphenous vein grafts has been associated with less favorable results than in native coronary arteries owing to a higher acute complication rate and an increased incidence of restenosis. We placed 16 nonarticulated balloon expandable stainless steel "biliary" stents at the sites of 13 stenotic or occluded aortocoronary saphenous vein graft lesions in 11 patients. All of the lesions were stented successfully. There were no instances of stent thrombosis or stent embolism. The percent diameter stenosis was reduced from 85.5 +/- 14.1% to 3.5 +/- 4.4% (p < .001), and the minimal lumen diameter of the lesion increased from 0.7 +/- 0.7 mm at baseline to 3.7 +/- 0.2 mm (p < .001) after stent placement. We conclude that this noncoronary stent appears to be safe and effective for treating saphenous vein coronary bypass grafts. The high procedural success rate and excellent angiographic results are very encouraging, while the restenosis rates remain to be determined.

Angioplasty, Balloon, Coronary↗
PubMed1993

High-speed rotational ablation (Rotablator) for unfavorable lesions in peripheral arteries.

A strategy of using a single, conservatively sized percutaneous transluminal rotational ablation device with or without adjunctive balloon angioplasty was employed in 18 vessels in 17 patients selected because of unfavorable lesion morphology for balloon angioplasty alone. Fifteen patients had lower extremity occlusions and/or heavily calcified lesions and two patients had ostial renal artery stenoses. We were able to achieve a 94% (17/18 lesions) technical success rate, and a 94% (16/17 patients) clinical success rate. In the patients with lower extremity lesions, the baseline ankle-brachial blood pressure index increased from 0.55 +/- 0.15 to 0.90 +/- 0.19 (p < .001) 1 day after the procedure. Follow-up at 6.8 +/- 2.8 months revealed clinical evidence of restenosis in only one patient. We conclude that a cost-effective strategy of treating unfavorable lesions with a single Rotablator burr and adjunctive balloon angioplasty is safe and effective.

Adult↗
PubMed1993

Holmium: YAG laser-assisted coronary angioplasty with multifiber delivery catheters.

Mid-infrared lasers are attractive for coronary angioplasty based upon their excellent fiberoptic transmission and enhanced tissue absorption. Using a solid-state, mid-infrared holmium:YAG laser with prototype multifiber laser delivery catheters, we performed coronary laser angioplasty with or without adjunctive balloon angioplasty or directional atherectomy in 14 patients with 17 stenoses. Procedural laser success was obtained in 13/14 (93%) patients and 16/17 (94%) lesions; however clinical success was achieved in 9/14 (64%) patients and 12/17 (71%) stenoses. Angiographic restenosis at 4.6 +/- 1.6 months was found in 5/8 (63%) patients. We achieved an excellent procedural laser success rate in patients with generally unfavorable angioplasty anatomy. However, our clinical success rate was not different from that expected with conventional angioplasty alone. The holmium laser remains an attractive energy source for laser angioplasty; but as is the case for all coronary laser systems, its utility as a stand-alone therapy is limited by catheters which create small channels. In this small group, we could demonstrate no clinical benefit for laser-assisted angioplasty in complex coronary lesions. Our results suggest that a randomized trial comparing laser-assisted angioplasty and conventional angioplasty be performed to determine the clinical benefits of this more expensive therapy.

Adult↗
PubMed1993

In vitro poly-(ADP-ribosyl)ation of chromatin proteins in the rat tapeworm, Hymenolepis diminuta.

1. (ADP-ribose)-transferase activity in crude chromatin of H. diminuta was demonstrated. 2. Chromatin proteins were ADP-ribosylated in vitro and selectively extracted. 60, 12 and 18% of the (ADP-ribose)n of chromatin proteins was associated with total histones, histone H1 and histone H2B, respectively. 3. The extent of oligo-(ADP-ribose) compared to total (ADP-ribose)n in the chromatin fraction, in the histone fraction, the histone H1 fraction and the histone H2B fraction was 45, 60, 26 and 49%, with an average chain length of 2.8, 2.1, 1.8 and 2.6, respectively. 4. Analysis of (ADP-ribosyl)n-ated proteins by acetic acid/urea polyacrylamide gel electrophoresis demonstrated that histone H1, histone H2B and a 35 kDa non-histone protein were major (ADP-ribose)n acceptors.

Adenosine Diphosphate Ribose↗
PubMed1993

Percutaneous angioscopy of saphenous vein coronary bypass grafts.

OBJECTIVES: We compared the results of percutaneous angioscopy and angiography for detecting critical elements of surface lesion morphology in 21 patients undergoing balloon angioplasty of saphenous vein coronary bypass grafts. BACKGROUND: Angiography remains the standard for diagnosing and treating intravascular pathology associated with atherosclerotic coronary artery disease. It has been demonstrated that coronary angioscopy is more sensitive for identifying more complex atherosclerotic plaques and intracoronary thrombi in native coronary arteries. METHODS: Angioscopy and angiography were performed before and after angioplasty of "culprit lesions" in bypass grafts. All but one of the patients had unstable angina. The mean age of the saphenous vein coronary bypass grafts was 10.1 +/- 2.4 years (range 5 to 15). RESULTS: Restenosis at a prior angioplasty site was present in seven patients. Intravascular thrombi were seen by angioscopy in 15 (71%) of 21 versus 4 (19%) of 21 grafts by angiography (p < 0.001). Dissection was identified by angioscopy in 14 (66%) of 21 versus 2 (9.5%) of 21 grafts by angiography (p < 0.01). The presence of friable plaque lining the lumen surface of the vein graft was detected by angioscopy in 11 (52%) of 21 versus 4 (19%) of 21 grafts by angiography (p < 0.05). There was no correlation between age of the bypass graft and the finding of friable plaque. CONCLUSIONS: We conclude that angioscopy is superior to angiography for detecting complex lesion morphology in bypass grafts and that the presence of friable plaque does not preclude an uncomplicated angioplasty procedure.

Aged↗
PubMed1993

Comparison of operative reconstruction and percutaneous balloon dilatation for central venous obstruction.

To evaluate the efficacy of venous reconstruction versus percutaneous transluminal angioplasty for the treatment of obstruction of the superior vena cava and its major tributaries, we retrospectively reviewed the clinical course of 27 patients, of whom 13 underwent operative reconstruction and 15 had angioplasty (1 had both). Three patients had obstruction of the superior vena cava, 8 had occlusion of the innominate veins, and 16 had obstruction of the subclavian or axillary veins. In both treatment groups, mean age, indications, etiology, and location of the lesion were comparable. No major surgical complications occurred; one patient who underwent angioplasty experienced stent migration to the pulmonary artery without sequelae. Primary symptomatic relief at 1 year was achieved in 88% in the surgical group versus 36% in the angioplasty group (p < 0.05 by Fisher's exact test) and at 2 years in 71% versus 0%, respectively (p < 0.01). One- and 2-year success rates with repeated angioplasty, however, were 86% and 66% (p > 0.9), respectively. We conclude that the long-term success rate of operative reconstruction exceeds that of single percutaneous transluminal angioplasty. However, with repeated angioplasty, success rates approach those of operative reconstruction.

Aged↗
PubMed1993

The effect of decreasing amounts of live virus, while antigen content remains constant, on immunogenicity of Oka/Merck varicella vaccine.

The purpose of the study was to establish the minimum immunizing dose of stored Oka/Merck varicella vaccine and mimic effects of prolonged storage of vaccine at freezer temperatures. Ninety children were randomized to one of three groups: group A (1770 pfu/dose), group B (400-500 pfu/dose), or group C (80-160 pfu/dose). Seroconversion rates for groups A-C were 97%, 96%, and 92%, respectively. Group A and B vaccinees had higher antibody titers at 1 year than did group C subjects (P = .01). The difference between groups B and C approached significance (P = .058). At 1 year after immunization, 73%, 83%, and 80% in groups A-C, respectively, demonstrated cell-mediated responses. Since freshly reconstituted vaccine contains 1770 pfu/dose, vaccine failure from loss of potency is unlikely if vaccine is stored properly and administered promptly after reconstitution.

Antibodies, Viral↗