Search PubMed⌕ Search

Biomedical subjects

J A Bittl

Publications and source records attributed to J A Bittl.

At least 37 records · Page 2Linked to original sources
PubMed1997

Contemporary percutaneous treatment of unprotected left main coronary stenoses: initial results from a multicenter registry analysis 1994-1996.

BACKGROUND: Coronary artery bypass surgery (CABG) has been considered the therapy of choice for patients with unprotected left main (ULMT) coronary stenoses. Selected single-center reports suggest that the results of percutaneous intervention may now approach those of CABG. METHODS AND RESULTS: To assess the results of percutaneous ULMT treatment from a wide variety of experienced interventional centers, we requested data on consecutive patients treated after January 1, 1994, from 25 centers. One hundred seven patients were identified who were treated either electively (n=91) or for acute myocardial infarction (n=16). Of patients treated electively, 25% were considered inoperable, and 27% were considered high risk for bypass surgery. Primary treatment included stents (50%), directional atherectomy (24%), and balloon angioplasty (20%). Follow-up was 98.8% complete at 15+/-8 months. Results varied considerably, depending on presentation and treatment. For patients with acute myocardial infarction, technical success was achieved in 75%, and survival to hospital discharge was 31%. For elective patients, technical success was achieved in 98.9%, and in-hospital survival was strongly correlated with left ventricular ejection fraction (P=.003). Longer-term event (death, infarction, or bypass surgery) -free survival was correlated with ejection fraction (P<.001) and was inversely related to presentation with progressive or rest angina (P<.001). Surgical candidates with ejection fractions > or = 40% had an in-hospital survival of 98% and a 9-month event-free survival of 86+/-5%, whereas patients with ejection fractions < 40% had 67% and 22+/-12% in-hospital and 9-month event-free survivals, respectively. Nine hospital survivors (10.6%) experienced cardiac death within 6 months of hospital discharge. CONCLUSIONS: While results for selected patients appear promising, until early post-hospital discharge cardiac death can be better understood and minimized, percutaneous revascularization of ULMT stenosis should not be considered an alternative to bypass surgery for most patients. When percutaneous revascularization of ULMT is required, directional atherectomy and stenting appear to be the preferred techniques, and follow-up angiography 6 to 8 weeks after treatment is probably advisable.

Aged↗
PubMed1997

Excimer laser coronary angioplasty: the New Approaches to Coronary Intervention (NACI) experience.

In the New Approaches to Coronary Intervention (NACI) registry, 887 patients were electively treated with excimer laser coronary angioplasty (ELCA) for coronary artery disease. The Advanced Interventional System (AIS) system was used in 487 cases; the Spectranetics system, in 400. The mean age was 63.4 years. Most patients had unstable angina (60.3%); 43.7% had a prior myocardial infarction; and 18.6% were high risk or inoperable patients. Mean ejection fraction was 55.4%. A total of 1,000 lesions were treated in the 887 patients. Of the 1,000 lesions treated with ELCA in the 887 patients, 36% were in the right coronary artery; 33%, left anterior descending; 13%, circumflex; 3%, left main; and 16.6%, vein graft. By angiographic core laboratory analysis available for 752 (85%) patients with 839 lesions, lesions were 12.76 mm long. The minimum lumen diameter increased to 1.29 mm after the laser and finally to 1.95 mm after adjunctive percutaneous transluminal coronary angioplasty (PTCA) (which was performed in 93% of all lesions), with a final residual stenosis of 32.1% and Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow in 95%. Dissections of grades B, C, or D were seen after 22.0% of initial laser attempts, and postlaser perforations were noted in 2.6%. Additional such dissections accumulated after adjunctive PTCA but the perforation rate remained low. Procedural success was achieved in 84% of patients, but 1.2% died, 0.7% experienced Q-wave myocardial infarction (MI), and 2.7% required emergency bypass surgery. Multiple logistic regression analysis could not identify any independent predictors of these in-hospital complications. One-year mortality was 5.7% and the cumulative incidence of Q-wave MI was 1.5%. Coronary artery bypass graft (CABG) surgery was performed in 15.0% of patients whereas 25.5% required repeat percutaneous intervention with a target lesion revascularization rate of 31%. Independent predictors of death, Q-wave MI, or target lesion revascularization (which, combined, occurred in 35.6% of patients) were the absence of prior MI, ELCA in the circumflex, perforation after the procedure, and small (<2 mm) final minimal lumen diameter. Considering the large number of patients with high-risk lesions, laser angioplasty was performed with excellent procedural success rates and a reasonable incidence of major complications.

Aged↗
PubMed1997

Bivalirudin compared with heparin during coronary angioplasty for thrombus-containing lesions.

OBJECTIVES: We investigated whether bivalirudin is more effective than heparin in preventing ischemic complications in high risk patients undergoing coronary angioplasty for thrombus-containing lesions detected by angiography. BACKGROUND: Heparin is administered during coronary angioplasty to prevent closure of the dilated vessel. Bivalirudin (Hirulog) is a direct thrombin inhibitor that can be safely substituted for heparin during angioplasty. Bivalirudin has several theoretic advantages over heparin as an anticoagulant agent. METHODS: We performed an observational analysis of the Hirulog Angioplasty Study in which 4,098 patients with unstable or postinfarction angina were randomized to receive either bivalirudin or heparin during coronary angioplasty. The study group for this analysis consisted of 567 patients who had thrombus-containing lesions on angiography. The primary end point was death, myocardial infarction, emergency coronary artery bypass graft surgery or abrupt vessel closure before hospital discharge. RESULTS: Patients with thrombus-containing lesions had a higher incidence of myocardial infarction (5.1% vs. 3.2%, p = 0.03) and abrupt vessel closure (13.6% vs. 8.3%, p < 0.001) than those without thrombus. In patients with thrombus-containing lesions, however, the incidence of the primary end point was not different between the bivalirudin and heparin treatment groups. Furthermore, no difference in the incidence of ischemic events at 6 months was seen between the treatment groups. CONCLUSIONS: Bivalirudin is not more effective than heparin in preventing ischemic complications in patients undergoing coronary angioplasty for thrombus-containing lesions detected by angiography. Other approaches, perhaps involving potent anti-platelet agents, should be considered for patients with thrombus-containing lesions.

Aged↗
PubMed1996

Excimer laser angioplasty: focus on total occlusions.

This commentary reviews two studies published in the current issue of The American Journal of Cardiology, which provide important information about the use of excimer laser angioplasty for the treatment of chronic total occlusions. The commentary also summarizes fundamental laser mechanisms to clarify the shortcomings of excimer laser angioplasty--modest lumen improvement, prevalent vessel dissection, and troublesome restenosis--and to identify new applications of excimer laser technology.

Angioplasty, Balloon, Coronary↗
PubMed1996

Analysis and comparison of operator-specific outcomes in interventional cardiology. From a multicenter database of 4860 quality-controlled procedures.

BACKGROUND: Medical consumers are increasingly requesting methods to discriminate among the results of different providers. Standards for appropriate modeling, risk adjustment, and evaluation ("scorecarding") in this setting are not well developed, although such evaluation is being performed by the medical insurance industry and by several states in the United States. Our objectives were to develop and examine clinically meaningful methodology for assessing the operator-specific results for percutaneous coronary revascularization. METHODS AND RESULTS: From a multicenter database of patients treated since January 1, 1990, we used training and validation samples (n = 4860) to develop several models for risk adjustment and applied them to 38 providers performing 25 to 523 procedures in the database. Models were developed using multivariable logistic regression techniques for combinations of the end points of death, myocardial infarction, bypass surgery, and procedural success. Models were evaluated for predictive accuracy by using receiver operating characteristic (ROC) analysis, for the capacity to discriminate between superior and inferior provider outcomes, and for subjectivity and concordance. Major complications occurred in 3.6% of patients. The area under the ROC curve (with perfect discriminatory accuracy, area = 1.0; with no apparent accuracy, area = 0.5) in the validation sample, and frequency of identification of operators with outcomes outside the 95% CI for the outcome in question for the models were for death, 0.85 and 7.9%; for death, Q-wave infarction, and bypass surgery, 0.77 and 13.2%; for death, all infarction, and bypass surgery, 0.66 and 10.5%; and for procedural success, 0.76 and 23.7%. For the models as a group, identification of outliers was inversely related to provider volume (P = .05). Models evaluating non-Q-wave infarction or requiring measurement of percent diameter stenosis were identified as being most susceptible to provider manipulation. CONCLUSIONS: For percutaneous coronary revascularization, modeling to discriminate between provider outcomes is limited by the low incidence of major adverse events, subjectivity or susceptibility to manipulation of more frequently occurring adverse events, the generally modest predictive capacity of the models, and the low volume of individual provider treatments. Modeling will be most useful in the identification of providers with extremely poor outcomes and for discrimination between providers with very large procedural volume. Until improved understanding of the biological and mechanical correlates of major complications allows the development of more predictive models, interpretation of the results of scorecarding, particularly for low-volume providers, should be made with caution.

Female↗
PubMed1996

Clinical results with excimer laser coronary angioplasty.

This comprehensive review of randomized trials and registry reports makes several assertions about the clinical usefulness of excimer laser angioplasty. First, refinements in patient selection and excimer laser technique have resulted in improved procedural outcome. Second, the overall rates of clinical success for excimer laser angioplasty are approximately 90%, major and minor complications 6%, and vessel perforation 1%. Third, superior success rates are achieved for saphenous vein graft lesions, ostial stenoses and total occlusions, but decreased success rates are obtained for bifurcation, calcified and thrombus-containing lesions. The routine use of saline infusion during excimer laser angioplasty and careful evaluation of this therapy for new indications such as in-stent restenosis will increase the usefulness of excimer laser angioplasty in interventional cardiovascular medicine.

Angioplasty, Balloon, Coronary↗
PubMed1995

Effect of intracoronary saline infusion on dissection during excimer laser coronary angioplasty: a randomized trial. The Percutaneous Excimer Laser Coronary Angioplasty (PELCA) Investigators.

OBJECTIVES: We sought to evaluate whether intracoronary saline infusion during excimer laser coronary angioplasty decreases the incidence of significant laser-induced coronary artery dissections. BACKGROUND: Despite procedural success rates > 90%, coronary artery dissections occur in 17% to 27% of excimer laser coronary angioplasty procedures. Excimer laser irradiation of blood results in vapor bubble formation and acoustomechanical trauma to the vessel wall. Saline infusion into a coronary artery may minimize blood irradiation and consequent arterial wall damage. METHODS: In this prospective, randomized, controlled study, consecutive patients undergoing excimer laser coronary angioplasty were randomly assigned to conventional laser irradiation in a blood medium or to laser irradiation with blood displacement by intracoronary saline infusion. In the patients randomized to intracoronary saline infusion, prewarmed normal saline was injected through the coronary artery guide catheter at a rate of 1 to 2 ml/s using a power injector. The incidence and severity of dissection after excimer laser ablation were evaluated in a core laboratory by angiographers with no knowledge of treatment assignment. The severity of coronary artery dissection was rated on an ordinal scale of 1 to 5. Dissections of grade 2 or higher were considered significant. RESULTS: The mean (+/- SE) dissection grade after laser angioplasty in patients treated with intracoronary saline infusion was 0.43 +/- 0.13 compared with 0.91 +/- 0.26 in patients undergoing laser angioplasty in a blood medium. The incidence of significant dissection was 7% in saline-treated patients compared with 24% in conventionally treated patients (p < 0.05). No significant complications were associated with saline infusion. CONCLUSIONS: Intracoronary saline infusion should be incorporated into all excimer laser coronary angioplasty procedures.

Aged↗
PubMed1995

Treatment with bivalirudin (Hirulog) as compared with heparin during coronary angioplasty for unstable or postinfarction angina. Hirulog Angioplasty Study Investigators.

BACKGROUND: Heparin is often administered during and after coronary angioplasty to prevent closure of the dilated vessel. However, ischemic or hemorrhagic complications occur in 5 to 10 percent of treated patients. We studied whether these complications could be prevented when the direct thrombin inhibitor bivalirudin (Hirulog) was used in place of heparin. METHODS: We performed a double-blind, randomized trial in 4098 patients undergoing angioplasty for unstable or postinfarction angina. Patients were assigned to receive either heparin or bivalirudin immediately before angioplasty. The primary end point were death in the hospital, myocardial infarction, abrupt vessel closure, or rapid clinical deterioration of cardiac origin. RESULTS: In the total study group, bivalirudin did not significantly reduce the incidence of the primary end point (11.4 percent, vs. 12.2 percent for heparin) but did result in a lower incidence of bleeding (3.8 percent vs. 9.8 percent, P < 0.001). In the prospectively stratified subgroup of 704 patients with postinfarction angina, bivalirudin therapy resulted in a lower incidence of the primary end point (9.1 percent vs. 14.2 percent, P = 0.04) and a lower incidence of bleeding (3.0 percent vs. 11.1 percent, P < 0.001), but in a similar cumulative rate of death, myocardial infarction, and repeated revascularization in the six months after angioplasty (20.5 percent vs. 25.1 percent, P = 0.17). CONCLUSIONS: Bivalirudin was at least as effective as high-dose heparin in preventing ischemic complications in patients who underwent angioplasty for unstable angina, and it carried a lower risk of bleeding. Bivalirudin, as compared with heparin, reduced the risk of immediate ischemic complications in patients with postinfarction angina, but this difference was no longer apparent after six months.

Aged↗
PubMed1995

Early and late quantitative angiographic results of vein graft lesions treated by excimer laser with adjunctive balloon angioplasty.

BACKGROUND: Percutaneous excimer laser coronary angioplasty (PELCA) has been approved for treatment of diseased saphenous vein bypass grafts. However, detailed and complete quantitative angiographic analysis of immediate procedural and late follow-up results has not been performed. METHODS AND RESULTS: PELCA using the CVX-300 excimer laser system was performed in 125 bypass lesions (mean graft age, 96 +/- 53 months; range, 2 to 240 months) in 106 consecutive patients at eight centers. Quantitative analyses of the procedural and follow-up angiograms were done with the Cardiac Measurement System. Stand-alone PELCA was done in 21 lesions (17%). Lesions were located at the ostium (20%), body (67%), or distal anastomosis (13%). The graft reference diameter was 3.26 +/- 0.79 mm (mean +/- SD). Minimal lumen diameter increased from 1.09 +/- 0.52 mm before treatment to 1.61 +/- 0.69 mm after laser and 2.18 +/- 0.63 mm after adjunctive balloon dilation (P < .001) but had declined at follow-up to 1.40 +/- 1.17 mm. Dissections were evident in 45% of lesions after laser treatment (types A and B, 27%; types C through F, 18%), including 7% occlusions. Angiographic success (< or = 50% diameter stenosis [% DS]) was 54% after laser and 91% after adjunctive PTCA, with an overall clinical success rate of 89%. In-hospital complications were death, 0.9%; myocardial infarction (Q-wave and non-Q-wave), 4.5%; and bypass surgery, 0.9%. Independent predictors of % DS after laser were reference diameter, lesion length, and minimal lumen diameter before laser. At angiographic follow-up in 83% of eligible patients, the restenosis rate per lesion (DS > 50%) was 52%, including 23 occlusions (24%). The only independent predictor of increased % DS at follow-up was lesion symmetry. Logistic regression indicated that smaller reference diameter was an independent predictor of late occlusion. Overall 1-year mortality was 8.6%. Actuarial event-free survival (freedom from death, myocardial infarction, bypass surgery, or target vessel percutaneous transluminal coronary angioplasty) was 48.2% at 1 year. CONCLUSIONS: Excimer laser angioplasty with adjunctive balloon angioplasty can be safely and successfully performed in diseased, old saphenous vein bypass graft lesions considered at high risk for reintervention. The extent of laser ablation remains limited by the diameter and effectiveness of the catheters. Late restenosis and, in particular, total occlusion mitigate the early benefits of the procedure. Other approaches such as the routine use of additional anticoagulation (eg, warfarin) should be considered to reduce the risk of late occlusions and restenosis after laser angioplasty of bypass grafts.

Aged↗
PubMed1995

Orthodeoxia-platypnea due to intracardiac shunting--relief with transcatheter double umbrella closure.

The safety and efficacy of transcatheter clamshell occlusion of patent foramen ovale for relief of severe arterial desaturation and dyspnea in the upright position due to intracardiac shunting were examined in eight patients with excessive risk of surgical patent foramen ovale closure. All patients had successful reduction of intracardiac shunting with an immediate rise in oxygen saturation > or = 95% by implantation of a clamshell device on the atrial septum. Despite two early incidents of device embolization, retrieval and immediate re-implantation, and one patient with nonsustained atrial and ventricular arrhythmias, there were no adverse clinical sequelae. In follow-up evaluation transcatheter clamshell closure of patent foramen ovale has provided persistent relief from shunt-related arterial desaturation and symptomatology in all living patients.

Adult↗
PubMed1995

Comparative safety profiles of hirulog and heparin in patients undergoing coronary angioplasty. The Hirulog Angioplasty Study Investigators.

Several new anticoagulants and antiplatelet agents have been developed for use in coronary angioplasty, but almost all have been associated with an increased incidence of bleeding complications. Hirulog, a direct thrombin inhibitor, has several theoretical advantages over heparin. It is unclear, however, whether the use of hirulog as a substitute for heparin in angioplasty would result in a higher incidence of bleeding or other side effects. The safety profile of hirulog was compared with that of heparin in a randomized, double-blind trial in 4312 patients who were scheduled to undergo angioplasty for unstable or postinfarction angina. The goal of anticoagulation was to achieve an activated clotting time of approximately 350 seconds with hirulog (bolus dose of 1.0 mg/kg body weight followed by a 4-hour infusion of 2.5 mg/kg per hour and a 14- to 20-hour infusion of 0.2 mg/kg per hour) or heparin (bolus dose of 175 units/kg followed by an 18- to 24-hour infusion of 15 units/kg per hour). Adverse events were recorded prospectively by study personnel and confirmed independently by clinical monitors blinded to treatment assignment. Compared with heparin in an intention-to-treat analysis, hirulog therapy was associated with either equivalent or lower rates of side effects. Most of the side effects of hirulog and heparin were related to hemorrhagic complications such as intravascular puncture site hemorrhage (29.1% vs 61.6%; p < 0.001), hematuria (16.6% vs 20.6%; p = 0.001), bleeding requiring red cell transfusion (3.7% vs 8.6%; p < 0.001), or hematemesis (0.8% vs 1.9%; p = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗