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Biomedical subjects

M C Bates

Publications and source records attributed to M C Bates.

13 recordsLinked to original sources

Comparative study of operative treatment and percutaneous transluminal angioplasty/stenting for recurrent carotid disease.

PURPOSE: This study is a nonrandomized parallel comparison of the outcome for carotid endarterectomy (CEA) and percutaneous transluminal angioplasty (PTA)/stenting for recurrent carotid artery stenosis (RCS). METHODS AND PATIENTS: Between June 1996 and June 2000, 83 carotid procedures (58 reoperations, Group I, and 25 PTA/stentings, Group II) were done for RCS. Patients were followed at regular intervals with duplex ultrasound scanning. The outcome of the stented group (Group II) was divided into early experience (Group IIA, first 12 cases) and late experience (Group IIB, last 13 cases) for learning curve consideration, and each was compared with the reoperation group. A Kaplan-Meier life table analysis was used to estimate the stroke-free survival rates and freedom from > or =50% recurrent restenosis for both groups. RESULTS: The demographic and clinical characteristics and indications for intervention were similar for both groups. The mean time from the original CEA to reoperation was 41 months in Group I versus 43 months in Group II. Overall, stenting had higher 30-day stroke rates than reoperations-16% (3 major and 1 minor stroke) versus 3.4% (1 out of 2 [1.7%] was a major stroke, P <.05). However, Group IIB had similar major stroke rates to Group I (0% versus 1.7%). Cranial nerve injury was noted in 10 patients (17%) in Group I (only 1 [1.7%] was permanent) versus 0% in Group II (P <.05). Recurrent > or =50% restenosis was higher in Group II than in Group I (24% versus 0%, P <.001). Stroke-free survival rates at 6 months and 1, 2, and 3 years for Group I were 97%, 97%, 94%, and 82%, respectively, versus 79%, 79%, 79%, and 79%, respectively, for Group II (P =.059). Freedom from recurrent > or =50% restenosis rates at 6 months and 1, 2, and 3 years were 100%, 100%, 100%, and 100%, respectively, for Group I versus 100%, 94%, 65%, and 44%, respectively, for Group II (P <.0001). CONCLUSIONS: Carotid PTA/stenting has a similar 30-day stroke rate to that of reoperation for RCS once experience is established. However, PTA/stenting has a higher incidence of restenosis than reoperation, which is associated with a percentage of cranial nerve injuries. Therefore, PTA/stenting can be an alternative to reoperation, particularly in marginal surgical risk patients.

Aged↗

Cerebral protection systems for distal emboli during carotid artery interventions.

Carotid angioplasty and stenting is associated with liberation of cerebral emboli that can cause periprocedural stroke. There are currently three classes of emboli protection devices (EPDs) that are undergoing feasibility studies and one randomized clinical trial. Preliminary data from a small series appear to be promising, and there appears to be attenuation of embolic signals on a cerebral Doppler exam with EPD use. However, rare strokes and patient intolerance due to imposed ischemia have been observed. The advantages and disadvantages of each EPD class and the issues involving clinical trials and surrogate end points in this area of study are discussed.

Angioplasty↗

Acute profound thrombocytopenia following C7E3 Fab (Abciximab) therapy: case reports, review of the literature and implications for therapy.

Platelets play a crucial role in the ischemic complications of percutaneous coronary procedures. The recent availability of C7E3 Fab (Abxiximab or ReoProtrade mark), a chimeric monoclonal antibody Fab fragment directed against the platelet glycoprotein IIb/IIIa receptor, has reduced abrupt closure and other adverse events and lessened the need for revascularization procedures. As the use for this drug has increased, rare cases of severe thrombocytopenia have been revealed. From August 1995 to June 1997, 452 patients at Charleston Area Medical Center who underwent percutaneous coronary revascularization procedures and were treated with abciximab were evaluated for the development of severe thrombocytopenia (i.e., platelet count less than 20,000 within 48 hr of treatment). A review of published reports of severe thrombocytopenia was also reviewed. A review of published reports of abciximab-induced severe thrombocytopenia, as well as our three cases, reveals that: 1) the incidence is less than 0.7%; 2) the nadir platelet count (range 1, 000-16,000) was noted within 2-31 hr after abciximab infusion; 3) the platelet count increases to greater than 100,000 within 12 days in all patients; 4) bleeding episodes were treated with platelet transfusion with an improvement in platelet count within 24 hr in all patients in whom they were given; and 5) in the one patient treated with gamma globulin alone, no significant rise in platelet count was noted. Acute severe thrombocytopenia can occur after ReoProtrade mark administration. Its development is not predictable and may occur within 2 hr of administration. Thrombocytopenia, therefore, requires consideration in every patient treated with this drug. It appears prudent to obtain a platelet count 2 hr after initiating ReoProtrade mark. If thrombocytopenia develops, then the drug can be stopped in a timely manner and platelet transfusion can be given.

Abciximab↗

Primary stent deployment in occlusive subclavian artery disease.

Primary (without antecedent balloon dilation) Palmaz stent implantation was successfully performed in 27 consecutive patients entering with 31 obstructed subclavian arteries. Stents (n = 50) were successfully deployed, using the brachial (n = 7), femoral (n = 16), or combined (n = 8) approach, to revascularize 31 subclavian vessels [8 occluded (26%); 23 stenotic (74%)], using a 6 or 7.5 French delivery system. The indications for intervention were arm claudication in 8 patients (30%), subclavian steal syndrome in 11 patients (41%), angina pectoris secondary to impaired blood flow to the left internal mammary artery coronary bypass in 6 patients (22%), and recanalization of a left subclavian occlusion to permit central arterial access and performance of a second interventional procedure 2 patients (7%). The percent diameter stenosis improved from 85 +/- 12% to 6 +/- 7% (P < 0.001); and, the peak and mean translesion gradients decreased, respectively, from 56 +/- 35 mm Hg to 3 +/- 4 mm Hg (P < 0.01), and 29 +/- 18 mm Hg to 2 +/- 2 mm Hg (P < 0.01). Procedural complications encountered were one stent dislodgement with migration into and uneventful deployment within the right external iliac artery, and two brachial artery repairs. No acute vessel closures, deaths, myocardial infarctions, cerebrovascular accidents, transient ischemic attacks, or need for transfusions occurred. Therefore, primary subclavian artery stent deployment can be performed using low-profile sheath systems with excellent success (100%), resulting in immediate restoration of pulsatile flow, and few complications. The incidence of lesion recurrence remains for follow-up studies.

Adult↗

Continued benefit of lovastatin in the treatment of hypercholesterolemia in 36 patients.

After one year of treatment, low-dose (20 mg/d) lovastatin achieved continued efficacy without tachyphylaxis in 36 patients with Type IIa or IIb hyperlipoproteinemia. Six week and one year reductions in low density lipoprotein (LDL) cholesterol were significant at 33% and 31% in these patients respectively; reductions in total cholesterol were also significant at 25% and 22% respectively. Increases in high density lipoprotein cholesterol (HDL) were 6% at six weeks and 10% at one year; triglycerides were reduced 16% and 11% respectively. The cholesterol lowering effects were similar for males and females (23% and 21% respectively). Low-dose lovastatin (20 mg/d) is a good choice for reducing cholesterol in patients with primary Type IIa or IIb hyperlipoproteinemia refractory to diet therapy because it is effective in lowering LDL-cholesterol, while raising HDL-cholesterol with few side effects and without tachyphylaxis.

Aged↗

The use of Gianturco-Roubin flexible metallic coronary stents in old saphenous vein grafts: in-hospital outcome and 7 day angiographic patency.

After placement of a Gianturco-Roubin metallic, coiled coronary stent(s) following balloon angioplasty (PTCA), a pre-discharge (7 day) angiogram determined the patency of the old coronary bypass vein graft(s) (SVG) (> or = 5 years remote from their last surgery, mean age: 8.5 +/- 1.8 years). Metallic, coiled stents were successfully deployed in 95/96 (99%) patients within 100/101 (99%) SVGs. The indications for deployment were threatened [81 patients (84%)] or acute [15 patients (16%)] vein graft closure following PTCA. Intragraft urokinase infusion was performed in 17 patients (17%) [6 patients with baseline occlusions; 11 with abrupt closure post PTCA]. Complications encountered included three (3%) in-hospital deaths (two procedure related) two (2%) Q wave myocardial infarctions, six (6%) non-Q wave myocardial infarctions, and 22 (22%) bleeding problems. These included, not mutually exclusively, 21 (22%) requiring transfusions, six (6%) cases of gastrointestinal bleeding, six (6%) pseudoaneurysms, five (5%) retroperitoneal haemorrhages and two (2%) cerebrovascular accidents. All patients received dipyridamole, aspirin, dextran, and anticoagulation (heparin 10-20,000 U intra-procedurally); a heparin infusion was continued for 5 +/- 1 days, despite warfarin administration which attained a therapeutic prothrombin time (PT) (1.5-2 times control) by 3 +/- 1 days. Out of the 95 successfully treated patients, six with eight stented grafts were ineligible for pre-discharge angiography. Of the six, three died in hospital (four SVGs), one had an intracerebral haemorrhage (one SVG), and two were asymptomatic patients with chronic renal failure (three SVGs).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Tracheal carinal angle and left atrial size.

Left atrial enlargement is a significant finding, usually indicating elevated left ventricular end-diastolic pressure. An increased tracheal carinal angle has been reported as one indicator on chest radiography of left atrial enlargement. This study retrospectively compared echocardiographically determined left atrial size with carinal angle on plain films. Enlarged left atria and paired, age-matched normal left atria by echocardiography were selected. The carinal angle was measured on roentgenogram (standard and portable films) by goniometer. The left atrium could be accurately predicted to be larger than 5.0 cm in diameter if the carinal angle was 100 degrees or greater. A carinal angle greater than 100 degrees is an easy, inexpensive, reliable method of predicting left atrial enlargement.

Adult↗

Effectiveness of low-dose lovastatin in lowering serum cholesterol. Experience with 56 patients.

This study reviews the progress of 56 consecutive patients with type IIa and IIb hyperlipoproteinemia following treatment with lovastatin. Lovastatin, a potent inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, has been shown to have a cholesterol-lowering effect in doses ranging from 10 to 80 mg/d. Thus far, however, no large study has been performed to show the effectiveness of low-dose lovastatin (20 mg/d) for more than a 6-week duration. Fifty-six patients with known coronary artery disease were prospectively studied, with fasting lipid values being measured at baseline and after 6, 12, 18, and 24 weeks of 20-mg/d lovastatin therapy given as a single evening dose. The total cholesterol level fell 26% from a mean baseline of 8.12 mmol/L (314 mg/dL) and triglyceride levels fell by 12% from a mean baseline of 2.46 mmol/L. The high-density lipoprotein levels increased 7.6%. One patient with known preexisting liver disease was withdrawn from the study owing to an asymptomatic significant rise in liver function test results; one subject complaining of proximal muscle weakness was also withdrawn. The maximal decrease in total cholesterol level occurred within 6 weeks of initiation of therapy. We conclude that low-dose (20-mg/d) lovastatin was effective in lowering serum cholesterol levels in patients with primary type IIa or IIb hyperlipoproteinemia with minimal short-term side effects. Further studies are needed to establish the long-term safety and effectiveness of this drug.

Cholesterol↗

Xanthelasma: clinical indicator of decreased levels of high-density lipoprotein cholesterol.

The fasting plasma lipid and lipoprotein levels were measured prospectively in 41 consecutive patients with xanthelasma seen over a four-year period. The study group included 25 women and 16 men with mean ages of 60 and 56 years, respectively. Each patient had clinical evaluation for medications or illnesses that might affect plasma lipid levels before entry into the study. The most striking lipid abnormality was the preponderance of decreased levels of high-density lipoprotein cholesterol (HDL-C). In 94% of the study population, HDL-C values were less than the mean values of the age-matched reference population. For men the mean HDL-C level was 30.8 mg/dl (vs 45 mg/dl in the reference population, P less than .001); for women the mean HDL-C level was 33 mg/dl (vs 50 mg/dl, P less than .001). The total cholesterol, low-density lipoprotein, and triglyceride levels of those in the study were not significantly different from those of the patients in the reference population. Evaluation of cardiac risk based solely on HDL-C levels showed 80% of the study population to have three to four times the average risk. This study points out the high probability of decreased HDL-C levels in patients with xanthelasma. Since the level of HDL-C has been shown to be inversely related to the incidence of cardiovascular disease, it may be prudent to evaluate HDL-C levels and do a thorough cardiovascular evaluation in patients with xanthelasma.

Adult↗

Endovascular repair of abdominal aortic aneurysms: our early experience.

Endovascular repair of abdominal aortic aneurysms (AAA) seems to hold the potential for decreased perioperative mortality and morbidity associated with the standard open repair by eliminating major surgical exposure of the aorta and prolonged aortic cross-clamping. After several years of FDA-approved clinical trials of multiple aortic-stented grafts, the FDA, in September 1999, approved two devices (the ANCURE and the AneuRx) for commercial use in the United States. We implanted the first device in the Tri-State area at the Charleston Area Medical Center (CAMC) on Feb. 6, 2000, and this study reviews our early experiences with 15 patients utilizing these two devices at CAMC.

Aged↗