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Biomedical subjects

C J White

Publications and source records attributed to C J White.

At least 37 records · Page 2Linked to original sources
PubMed1998

Coronary stenting in cardiac allograft vasculopathy.

OBJECTIVE: The purpose of this study was to evaluate acute angiographic success, in-hospital complications and long-term outcome after intracoronary stenting in patients with cardiac allograft vasculopathy. BACKGROUND: The application of conventional interventional modalities to treat discrete lesions in patients with cardiac allograft vasculopathy is associated with higher procedural morbidity, mortality and higher restenosis compared to atherosclerotic coronary artery disease. Elective coronary stenting has been shown to lower restenosis rates and improve long-term outcome in selected patients with native coronary artery disease; however, its safety and efficacy in reducing restenosis in patients with cardiac allograft vasculopathy is unknown. METHODS: Ten patients with 19 discrete lesions in a major coronary artery without diffuse distal disease underwent intracoronary stenting using Palmaz-Schatz stents. The average stent size was 3.4 mm, and the stent/artery ratio was 0.99+/-0.07. Eight of ten (80%) patients received antiplatelet therapy (aspirin plus ticlopidine) only. RESULTS: Procedural success was 100% with no in-hospital stent thrombosis, Q-wave myocardial infarction or death. Minimal luminal diameter increased from 0.83+/-0.38 mm to 3.23+/-0.49 mm after stenting. Diameter stenosis decreased from 74.91+/-11.52% to 5.90+/-4.09% after stenting. Follow-up angiography was performed in 8 of 10 (80%) patients and 16 of 19 (84%) lesions. Target lesion revascularization was required in 2 of 10 (20%) patients and 3 of 16 (19%) lesions. Allograft survival was 7 of 10 (70%) at the end of 22+/-11 months follow-up. CONCLUSIONS: Intracoronary stenting can be performed safely with excellent angiographic success in selected patients with cardiac allograft vasculopathy. The restenosis rate appears to be low despite the aggressive nature of the disease. A multicenter study with a larger number of patients is required to assess its efficacy in reducing restenosis and improving allograft survival.

Coronary Angiography↗
PubMed1998

Rheolytic thrombectomy in the treatment of acute limb-threatening ischemia: immediate results and six-month follow-up of the multicenter AngioJet registry. Possis Peripheral AngioJet Study AngioJet Investigators.

We tested the efficacy of rheolytic thrombectomy in treating 21 patients (mean age 68+/-12 years; 66% male) and 22 vessels (limbs) who presented to the hospital within 2 weeks of the development of limb-threatening ischemia. Fifty-two percent had contraindications to use thrombolytics, and 57% had severe comorbidities. All of the vessels were occluded with thrombus on the initial angiogram. Procedural success was achieved in 20 limbs (91%). Three patients expired in the hospital, and one expired at follow-up due to nonvascular causes. Acute limb salvage was achieved in 18 of 19 limbs (95%) in the 18 survivors, and 6-month limb salvage was achieved in 16 of 18 limbs (89%) in the 17 survivors. Rheolytic thrombectomy is effective in restoring immediate blood flow in acute limb-threatening ischemia, especially in high-risk surgical patients or patients with contraindications to thrombolytic therapy.

Aged↗
PubMed1998

Morphologic comparison of atherosclerotic lesions in native coronary arteries and saphenous vein graphs with intracoronary angioscopy in patients with unstable angina.

BACKGROUND: Coronary vein grafts develop accelerated atherosclerosis after aortocoronary bypass surgery. Previous pathologic studies have suggested that the morphologic appearance of atherosclerotic lesions in saphenous vein grafts may have subtle differences compared with those of native coronary arteries and may be more prone to disruption and thrombus formation. However, a comparative in vivo assessment of the angioscopic morphology differences between these two types of vessels has not been reported previously. We compared the angioscopic lesion morphology of native coronary arteries and saphenous vein grafts in patients with unstable angina. METHODS AND RESULTS: Percutaneous coronary angioscopy was performed in 60 consecutive patients with unstable angina. Plaque color, texture, friability, and the presence of atherosclerotic plaque ulceration or intracoronary thrombus were noted in the culprit lesion. The culprit lesion was located in native coronary arteries in 42 (70%) patients and in a saphenous vein graft in 18 (30%) patients. There were no significant differences in age, sex, and coronary risk factors including tobacco use, hypertension, hypercholesterolemia, or diabetes mellitus between the two populations. There were also no significant differences between the two groups in terms of plaque color, surface texture, or the incidence of complex plaque morphology (plaque ulceration and intracoronary thrombosis). Loosely adherent, friable plaque, detected by angioscopy, was absent in native coronary arteries and was present in 44% of the saphenous vein grafts (p < 0.0001). CONCLUSIONS: The results of our angioscopic study indicate that other than a high incidence of plaque friability in vein grafts, the surface morphology of culprit lesions in unstable angina patients is quite similar for saphenous vein grafts and native coronary arteries.

Angina, Unstable↗
PubMed1998

Safety, tolerability and immunogenicity of concomitant injections in separate locations of M-M-R II, VARIVAX and TETRAMUNE in healthy children vs. concomitant injections of M-M-R II and TETRAMUNE followed six weeks later by VARIVAX.

OBJECTIVES AND STUDY DESIGN: The primary objectives of this study were to compare immunologic responses, antibody persistence, safety and varicella breakthrough rates when VARIVAX (varicella vaccine) is given at the same time as M-M-R II (measles, mumps, rubella vaccine) and TETRAMUNE (conjugate Haemophilus influenzae type b, diphtheria, tetanus and whole cell pertussis vaccine) at separate injection sites (Group A) vs. VARIVAX given 6 weeks after M-M-R II and TETRAMUNE (Group B). Six hundred nine healthy children, 12 to 23 months of age, were randomized to one of two treatment (immunization) groups (Group A and Group B). Blood for antibody titers was drawn on the day of immunization, 6 weeks after each injection and 1 year later. Local and systemic adverse reactions were recorded. Exposure and cases of varicella were documented through a 1-year follow-up period. RESULTS: Measles, mumps and rubella seroconversion rates and geometric mean titers (GMTs) were similar for both treatment groups. Varicella seroconversion rates were also similar between groups. However, varicella GMTs and percent with a varicella-protective level [> or =5.0 glycoprotein (gp) enzyme-linked immunosorbent assay (ELISA) units] did not meet the prespecified criteria for similarity were lower for Group A (GMT 10.5; 82.8% > or =5.0 gp ELISA units) than for Group B (GMT 14.5; 91.2% > or =5.0 gp ELISA units). The GMTs between groups for other antibodies were similar. At the 1-year follow-up antibody titers were comparable in both groups and breakthrough varicella cases appeared generally similar. There were fewer local adverse events (AEs) at the VARIVAX injection sites (9.8% and 2.9%, Group A and B, respectively) than at the TETRAMUNE sites (27.9% and 24.0%). Systemic AEs were not statistically different when M-M-R II was administered alone (8.6%) or concomitantly with VARIVAX (8.9%). When VARIVAX was given alone AEs were 1.8%. The rate of fever > or =102 degrees F after M-M-R II and TETRAMUNE administered together was 10.7% on Days 0 to 3 and 23.7% on Days 7 to 21. When VARIVAX was administered alone, the rate of fever was 5.4% on Days 0 to 3 (P = 0.018) and 10.8% on Days 7 to 21 (P<0.001). CONCLUSION: Because the varicella titers were comparable and varicella breakthrough rates generally similar at 1 year in both groups, we expect that the concomitant administration of VARIVAX with M-M-R II and TETRAMUNE has clinical effectiveness similar to that with VARIVAX 6 weeks after the administration of these other two vaccines. VARIVAX appears to be less reactogenic than M-M-R II and TETRAMUNE.

Antibodies, Bacterial↗
PubMed1998

Peripheral atherectomy with the Pullback Atherectomy Catheter: procedural safety and efficacy in a multicenter trial. PAC Investigators.

PURPOSE: To report the initial results of a newly designed catheter for percutaneous circumferential atherectomy in patients with lower extremity atherosclerotic occlusive disease. METHODS: The Pullback Atherectomy Catheter (PAC) is an over-the-wire device that circumferentially debulks atherosclerotic lesions in peripheral arteries up to 6 mm in diameter. Pullback atherectomy with or without adjunctive balloon angioplasty was attempted in 190 patients (246 lesions) with lower extremity lesions < or = 7.0 cm in length and a diameter stenosis > 50%. RESULTS: Angiographic success was accomplished in 95% (234/246) of the of the lesions attempted. The baseline ankle-brachial index rose from 0.61+/-0.20 to 0.83+/-0.20 (p < 0.001) at 24 hours after the procedure. There were no major complications (distal emboli, dissection, thrombosis, or perforation requiring surgical correction) attributable to pullback atherectomy. CONCLUSIONS: The acute results of pullback atherectomy demonstrate an extremely high technical success rate and an excellent safety record for lower extremity percutaneous revascularization. The catheter facilitates debulking longer lesions, but it is limited to small-diameter (< or = 6 mm) peripheral vessels.

Arteriosclerosis↗
PubMed1997

Renal artery stent placement: utility in lesions difficult to treat with balloon angioplasty.

OBJECTIVES: We assessed the safety and efficacy of stent placement in patients with poorly controlled hypertension and renal artery stenoses, which are difficult to treat with balloon angioplasty alone. BACKGROUND: Preliminary experience with stent placement suggests improved results over balloon angioplasty alone in patients with atherosclerotic renal artery stenosis. METHODS: Balloon-expandable stents were placed in 100 consecutive patients (133 renal arteries) with hypertension and renal artery stenosis. Sixty-seven of the patients had unilateral renal artery stenosis treated and 33 had bilateral renal artery stenoses treated with stents placed in both renal arteries. RESULTS: Angiographic success, as determined by quantitative angiography, was obtained in 132 (99%) of 133 lesions. Early clinical success was achieved in 76% of the patients. Six months after stent placement, the systolic blood pressure was reduced from 173 +/- 25 to 147 +/- 23 mm Hg (p < 0.001); the diastolic pressure from 88 +/- 17 to 76 +/- 12 mm Hg (p < 0.001); and the mean number of antihypertensive medications per patient from 2.6 +/- 1 to 2.0 +/- 0.9 (p < 0.001). Angiographic follow-up at a mean of 8.7 +/- 5.0 months in 67 patients revealed restenosis (>50% diameter narrowing) in 15 (19%) of 80 stented vessels. CONCLUSIONS: Renal artery stenting is an effective treatment for renovascular hypertension, with a low angiographic restenosis rate. Stent placement appears to be a very attractive therapy in patients with lesions difficult to treat with balloon angioplasty such as renal aorto-ostial lesions and restenotic lesions, as well as after a suboptimal balloon angioplasty result.

Aged↗
PubMed1997

Effects of renal artery stent implantation in patients with renovascular hypertension presenting with unstable angina or congestive heart failure.

This study evaluates the effect of renal artery stent implantation in patients with renovascular hypertension presenting with unstable angina (n = 20) or congestive heart failure (n = 28). There was a significant improvement in the Canadian Cardiovascular Society angina class and the New York Heart Association functional class, and at 8.4 +/- 6.4 month follow-up.

Aged↗
PubMed1997

Stent recoil: comparison of the Wiktor-GX coil and the Palmaz-Schatz tubular coronary stent.

Wiktor-GX coil stents and Palmaz-Schatz 154A tubular stents were implanted in a consecutive series of 40 patients and 45 arteries undergoing successful primary stent placement in de novo lesions treated with single stents in order to compare the acute recoil of a coil stent to a tubular stent in native coronary arteries. Acute stent recoil was determined by measuring the difference between the maximum inflated diameter of the stent deployment balloon and the minimum lumen diameter after stent deployment. There was no difference between the two groups for reference vessel diameter, nominal balloon diameter, maximum inflated balloon diameter, maximum inflation pressure, or poststent vessel minimum lumen diameter. Acute recoil averaged 0.15 +/- 0.2 mm for the Wiktor-GX and 0.13 +/- 0.1 for the Palmaz-Schatz (P = 0.58). In this series of patients, there was no significant difference between the acute recoil of the coil stent compared to the tubular stent.

Angioplasty, Balloon, Coronary↗
PubMed1997

Heterogeneity of cardiac allograft vasculopathy: clinical insights from coronary angioscopy.

OBJECTIVES: With this study, we sought to examine the heterogeneity of cardiac allograft vasculopathy in vivo using coronary angioscopy as an adjunct to intravascular ultrasound, and we evaluated the clinical relations of immunologic and nonimmunologic risk factors with the different forms of cardiac allograft vasculopathy detected angioscopically. BACKGROUND: Intravascular ultrasound detects vascular intimal proliferation accurately but is limited in its ability to delineate morphologic characteristics. Coronary angioscopy can evaluate intimal surface morphology by direct visualization and can differentiate pathologically distinct forms of plaque topography on the basis of color and contour. METHODS: We studied 107 consecutive heart transplant recipients with intravascular ultrasound and angioscopy at the time of their annual angiogram, and we assessed the relation of nonimmunologic and immunologic risk factors to the development of cardiac allograft vasculopathy distinguished angioscopically into a pigmented (yellow) or nonpigmented (white) intimal thickening. We further evaluated the clinical differences in cardiac events among these two forms of angioscopically heterogeneous forms of cardiac allograft vasculopathy. RESULTS: Significant clinical predictors of nonpigmented intimal thickening were advanced donor age and lower mean cyclosporine levels, whereas hyperlipidemia, cumulative prednisone dose and time since transplantation correlated with pigmented intimal hyperplasia. In addition, comparisons between the two angioscopic groups revealed increased intimal thickening, serum cholesterol, low density lipoprotein cholesterol, acute allograft rejection and time since transplantation in the group with pigmented intimal thickening (p < 0.05). With regard to cardiac events, nonpigmented plaque was more frequently found in the sudden death group (53% vs. 20%, p = 0.05), whereas the nonsudden cardiac event group had a significantly higher prevalence of pigmented plaque (80% vs. 47%, p = 0.07). CONCLUSIONS: These findings indicate that cardiac allograft vasculopathy is a heterogeneous disease with varied morphologic expressions with different clinical implications. Furthermore, this investigation provides insight into the cohesive, yet diverse influences of various factors, particularly immunosuppression, in these forms of cardiac allograft vasculopathy.

Adult↗
PubMed1997

Measles, mumps, rubella, and varicella combination vaccine: safety and immunogenicity alone and in combination with other vaccines given to children. Measles, Mumps, Rubella, Varicella Vaccine Study Group.

Eight hundred and twelve children, 12 months to 3.5 years of age, were enrolled in two clinical studies to evaluate the safety and immunogenicity of a live, attenuated combination vaccine for measles, mumps, rubella, and varicella (MMRV). Children were enrolled in one of two randomized, multicenter studies, involving administration of (1) MMRV and placebo vs. measles, mumps, and rubella vaccine (M-M-R(II)) and varicella-zoster virus vaccine (VARIVAX), given at separate anatomic sites at the same office visit; or (2) MMRV, DTaP (diphtheria, tetanus, and acellular pertussis vaccine) and OPV (oral polio vaccine) vs. M-M-R(II), DTaP, and OPV, with VARIVAX given 6 weeks later. All vaccine regimens were generally well tolerated. More than 95% of vaccinees seroconverted for measles, mumps, rubella, and varicella, regardless of the vaccine or regimen used. In each study, the level of antibody titer to varicella virus was significantly lower in vaccinees receiving MMRV than in those who received VARIVAX in a separate syringe.

Chickenpox Vaccine↗