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Biomedical subjects

N B Morris

Publications and source records attributed to N B Morris.

5 recordsLinked to original sources
PubMed1999

Utility of standby cardiopulmonary support for elective coronary interventions.

At our institution, elective coronary interventions are performed without formal surgical backup. Instead, a policy of "standby cardiopulmonary support" (CPS), and "next-available operating room" is used. Standby CPS requires a perfusionist dedicated to the catheterization laboratory with immediate access to CPS apparatus. Between January 1989 and June 1994 we performed 2,850 elective coronary interventions. Eleven patients (0.4%) required emergency CPS. None of these patients fell into a high-risk category for PTCA (i.e., sole circulation, ejection fraction <20%, unprotected left main). Eight of these (73%) had completion of their coronary intervention while on CPS in the catheterization laboratory. Three patients were sustained on CPS until an operating room became available. All patients required blood transfusions and sustained non-Q-wave myocardial infarctions. Two late in-hospital deaths occurred. Nine patients (82%) were successfully discharged. Standby CPS provides hemodynamic support for patients who sustain a potentially catastrophic event during coronary intervention. Our data suggest that this modality should not be limited to high-risk patients.

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PubMed1999

Brachytherapy. Savior or tease.

Dating from the inception of percutaneous coronary angioplasty, restenosis has been the postprocedural Achilles heel. Despite a decade of research, with a myriad of mechanical devices and pharmacologic agents, this vexing problem has yet to be resolved. Although intracoronary stents have proved effective at restenosis reduction, they have yet to achieve an acceptable level and, in some cases, remain resistant to any treatment. Intracoronary radiation using gamma or beta isotopes, has generated tremendous excitement with promising results. Indeed, the SCRIPPS (Scripps Coronary Radiation to Inhibit Proliferation Post Stenting) trial, which employed gamma radiation, showed a statistically significant reduction in restenosis in a small patient population. Further studies with a variety of isotopes and delivery modalities are currently underway, bringing with them their own assemblage of issues.

Angioplasty, Balloon, Coronary↗
PubMed1997

Catheter-based radiotherapy to inhibit restenosis after coronary stenting.

BACKGROUND: In animal models of coronary restenosis, intracoronary radiotherapy has been shown to reduce the intimal hyperplasia that is a part of restenosis. We studied the safety and efficacy of catheter-based intracoronary gamma radiation plus stenting to reduce coronary restenosis in patients with previous restenosis. METHODS: Patients with restenosis underwent coronary stenting, as required, and balloon dilation and were then randomly assigned to receive catheter-based irradiation with iridium-192 or placebo. Clinical follow-up was performed, with quantitative coronary angiographic and intravascular ultrasonographic measurements at six months. RESULTS: Fifty-five patients were enrolled; 26 were assigned to the iridium-192 group and 29 to the placebo group. Angiographic studies were performed in 53 patients (96 percent) at a mean (+/-SD) of 6.7+/-2.2 months. The mean minimal luminal diameter at follow-up was larger in the iridium-192 group than in the placebo group (2.43+/-0.78 mm vs. 1.85+/-0.89 mm, P=0.02). Late luminal loss was significantly lower in the iridium-192 group than in the placebo group (0.38+/-1.06 mm vs. 1.03+/-0.97 mm, P=0.03). Angiographically identified restenosis (stenosis of 50 percent or more of the luminal diameter at follow-up) occurred in 17 percent of the patients in the iridium-192 group, as compared with 54 percent of those in the placebo group (P= 0.01). There were no apparent complications of the treatment. CONCLUSIONS: In this preliminary, short-term study of patients with previous coronary restenosis, coronary stenting followed by catheter-based intracoronary radiotherapy substantially reduced the rate of subsequent restenosis.

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PubMed1995

Safety and efficacy of extended urokinase infusion plus stent deployment for treatment of obstructed, older saphenous vein grafts.

This study was designed to determine the safety and efficacy of extended, continuous infusion of urokinase plus stent deployment to treat older saphenous vein bypass grafts obstructed by both thrombus and atheromatous material. Thirty patients with angiographic evidence of thrombus and atheromatous material obstructing older vein grafts (mean age 8.3 years) underwent the combined interventions of urokinase infusion and stent deployment. The continuous infusion of urokinase was administered directly into each obstructed vein graft over a mean of 20.5 +/- 8.1 hours (median dose 2.2 +/- 0.7 million units). Stents were deployed at the sites of atheromatous obstruction either before (5 patients) or after (25 patients) infusion of urokinase. Twenty-eight of the 30 patients were successfully treated with the combined interventions (success rate 93.3%). In these 28 patients, percent diameter stenosis at the site of obstruction decreased from 86.0% to -0.2% and Thrombolysis in Myocardial Infarction trial flow increased from 1.0 to 2.5. Two patients (6.7%) developed stent thrombosis followed by myocardial infarction (1 with Q-wave infarction, 3.3%) and congestive heart failure. Minor complications included non-Q-wave myocardial infarction (5 patients, 16.7%) and access-site hemorrhage (5 patients, 16.7%). At 2-week follow-up, anginal symptoms were decreased in all 28 successfully treated patients. At 7.2 +/- 3.7-month follow-up, 5 of the 28 successfully treated patients (17.9%) had reacceleration of angina and angiographically documented restenosis at the site of stent deployment.(ABSTRACT TRUNCATED AT 250 WORDS)

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