Biomedical subjects
Publications and source records attributed to Christopher J White.
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BACKGROUND AND PURPOSE: We present our single-center experience using catheter-based therapy for acute ischemic stroke patients who were not candidates for intravenous thrombolytic therapy. METHODS: Neurologic outcomes were assessed in patients with acute ischemic stroke, ineligible for intravenous thrombolysis, treated with an emergent catheter-based therapy. RESULTS: Nonparametric analysis of neurological outcomes demonstrated a benefit in National Institutes of Health Stroke Scale (NIHSS) at long-term follow-up (P=0.036). Independence in daily activities and improvement in NIHSS of > or =4 points were achieved in 38% and 56% of patients, respectively. Four patients (25%) died, including 2 patients (12.5%) who died from intracranial hemorrhage. CONCLUSIONS: Catheter-based treatment offers a promising treatment strategy in patients with acute ischemic stroke ineligible for intravenous thrombolysis.
We performed percutaneous transluminal intervention in 20 consecutive patients (21 limbs) with common femoral artery (CFA) lesions causing symptomatic limb ischemia. In 12 limbs, concurrent additional percutaneous intervention proximal or distal to the target CFA lesion was performed. Angiographic success was obtained in 100%, with procedural success (angiographic success without a major in-hospital complications) in 90% and clinical success (procedural success and in-hospital improvement by at least one Fontaine functional class) in 81% of the limbs. The in-hospital Fontaine class improved by at least one functional class in 17 of 19 patients (89%), and the overall in-hospital event-free survival was 90% (18 of 20 patients). At follow-up (11.4 +/- 6 months), the overall event-free survival was 90% (18 of 20 patients) and 17 of 19 patients (89%) continue to show improvement by at least one functional (Fontaine) class. Percutaneous intervention of the CFA can be performed with a rate of high technical success and a low complication rate. It provides excellent clinical results at mid-term follow-up and appears to be a reasonable alternative to surgical therapy in patients at high risk for surgery.
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The objective of this study was to assess the feasibility, efficacy, and safety of rheolytic thrombectomy (RT) for treatment of coronary stent thrombosis. Stent thrombosis is an infrequent but potentially devastating complication. Conventional treatment with balloon angioplasty and/or thrombolysis has yielded suboptimal results. RT was used to treat 18 patients (mean age, 62 +/- 8 years; 72% male) with in-stent thrombosis (mean time to stent thrombosis, 2.4 +/- 1.8 days). Device success, procedure success, in-hospital and 30-day major cardiovascular events (MACE) were assessed in the hospital and at 30 days. Device success was obtained in 94% and procedure success was achieved in 100% of patients. Following RT, 11 patients underwent balloon angioplasty and 7 patients received additional stents. TIMI 3 coronary flow was obtained in 94.4% and all (100%) patients achieved either TIMI 2 or 3 coronary flow. The angiographic thrombus area decreased from 113.7 +/- 79 to 5.5 +/- 5.7 mm(2) after RT, and to 0.9 +/- 2.1 mm(2) (P < 0.001) after final treatment. Procedural complications were limited to transient no-reflow in five patients. Only one patient evolved a Q-wave MI. At 30 days of follow-up, no patients suffered death, emergent bypass surgery, or stroke. Our data suggest that the adjunctive use of rheolytic thrombectomy offers improved outcomes compared to prior results of intervention after coronary stent thrombosis and should be strongly considered as a treatment option for this complication.
Several patients developed sterile inflammation at their radial arterial access site. Pathologic examination of biopsy material from one patient demonstrated a foreign-body reaction to material most likely from the gel-coated arterial access sheath. Surgical excision of the inflamed tissue resulted in healing.
Percutaneous coronary interventions are performed with a high success rate, though failures still occur. Inability to deliver stents to the target lesion is the most common cause for failures. We present two cases using Rotaglide applied on the stents to enable delivery, showing that Rotaglide is effective in improving stent delivery.
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The management of extracranial carotid artery disease is primarily concerned with the prevention of acute stroke. In order to understand the current risks of carotid angiography performed by interventional cardiologists, we undertook a retrospective study to determine the neurologic complications in patients who underwent selective cerebral angiography. All patients undergoing studies that were limited to diagnostic aortic arch angiography and selective four-vessel cerebral angiography in the cardiac catheterization laboratories during the past 6 years were included in this study. Hospital records were reviewed to determine any in-hospital cerebrovascular complications following carotid angiography, ranging from transient ischemic attack to major disabling stroke or death. A total of 189 consecutive patients underwent 191 diagnostic studies limited to aortic arch and four-vessel cerebral angiography in the cardiac catheterization laboratories between 1 January 1995 and 31 December 2000. Only one (0.52%) neurological complication, a minor stroke, occurred in our study population. There were no transient ischemic attacks, major strokes, or death. We have shown that experienced interventional cardiologists can perform diagnostic aortic arch and selective carotid and vertebral angiography in a cardiac catheterization laboratory with a very low complication rate. Because the risks of angiography add to those of revascularization of the carotid artery, the most highly skilled angiographer, regardless of primary specialty, should perform these studies.
Percutaneous cardiac catheterization and endovascular procedures are associated with complications at the vascular access site. While surgery has been the traditional treatment for vascular access complications, the current state of the art permits percutaneous management of many access site complications. Surgical repair may be required only when percutaneous methods fail, are not available, or are unsuitable.
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We compared the safety, efficacy, and cost of the newly introduced percutaneous metallic commissurotome (PMC) with the results of Inoue balloon mitral valvuloplasty (BMV) in 80 patients with mitral stenosis (MS). The mean increase in mitral valve area (MVA) was 0.95 +/- 0.19 to 1.7 +/- 0.35 cm(2) for PMC and 0.97 +/- 0.15 to 1.81 +/- 0.36 cm(2) for BMV (P = NS). The Wilkins echocardiographic scores before dilatation did not correlate with any difference in MVA after dilatation. Bilateral commissural splitting was significantly more common with PMC than with BMV (30/39 patients, 76.9%, vs. 21/40 patients, 52.5%; P = 0.02). Postprocedural severe mitral regurgitation occurred in 1/39 (2.6%) in the PMC group and in 4/41 (9.8%) in the BMV group. Because the PMC device is resterilizable, we estimated the cost to be one-fourth the cost of BMV with the Inoue balloon. The estimated device cost ratio of PMC to BMV for each patient was 1 to 4.25. The early results of PMC on the MVA are comparable to BMV. However, PMC had better results not only in patients with high echocardiographic scores, but the PMC device splits commissural calcification better than BMV.
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The treatment of failing bypass grafts is difficult because repeat surgery carries a higher mortality rate than a first operation. Percutaneous intervention is more difficult because mechanical manipulation of these soft, friable atherosclerotic plaques have been associated with a significant rate of distal embolization, myocardial infarction, late restenosis and death. Balloon angioplasty alone has proven to have serious limitations in the treatment of older degenerated saphenous vein grafts (SVG). Although directional atherectomy yielded a higher angiographic success in a randomized trial, the restenosis rate was similar, and the procedural complications higher. The transluminal extraction catheter (TEC) has also shown significant limitations for the treatment of degenerated or thrombotic vein grafts with a significant procedural complication rate. A randomized trial comparing stenting versus balloon angioplasty in focal SVG lesions showed a higher freedom from major adverse cardiovascular events in the stent group, but there was no significant difference in the angiographic restenosis rates. More recently, rheolytic thrombectomy and mechanical thrombolysis have proven useful in treating thrombotic lesions in SVG. In addition, the recent development of distal protection devices appears very promising and will probably contribute to decreased distal embolization during percutaneous revascularization of these conduits.
Endovascular stenting of the extracranial carotid arteries is a viable treatment option to carotid endarterectomy in selected patients. Patients undergoing this procedure must be treated with aspirin 325 mg at least 24 hours prior to the procedure and clopidogrel 75 mg oral, three to five days prior to the procedure (or 300 mg at least six hours prior to stenting). During the intervention, heparin is given to maintain an activated clotting time of at least 300 seconds. Although there are theoretical advantages on the use of a platelet IIb/IIIa inhibitor, their routine use during elective carotid stenting is not recommended until their clinical benefits have been clearly demonstrated in this patient population. Hemodynamic instability during balloon inflation and stent deployment should be treated with intravenous fluids, atropine, and an alpha agonist such as neosynephrine. All the oral antihypertensive must be discontinued after the procedure and if there is persistence of hypotension making discontinuation of neosynephrine difficult, an oral alpha agonist such as midodrine (2.5 to 5 mg two to three times daily) is helpful. In the majority of patients this medication can be tapered off three to five days following stenting.