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Biomedical subjects

J S Douglas

Publications and source records attributed to J S Douglas.

At least 19 recordsLinked to original sources
PubMed2001

Trends in outcome and costs of coronary intervention in the 1990s.

Our objective was to examine trends in outcome and cost of percutaneous coronary intervention (PCI) between 1990 and 1999. PCI has become the most common form of myocardial revascularization in recent years, rivaling the more established coronary artery bypass surgery. There has been increasing interest in improving outcome of PCI while also seeking to minimize cost. A total of 21,755 patients undergoing PCI were evaluated. Clinical data were gathered from the Emory Cardiovascular Database and financial data from the UB92 formulation of the hospital bill. Charges were reduced to cost using departmental cost-to-charge ratios. Costs were inflated to 1999 dollars using medical care inflation rates. Mortality varied without a significant trend from 0.63% to 0.44% (p = 0.64). The Q-wave myocardial infarction rate decreased from 0.68% to 0.40% (p = 0.0003). Emergent coronary surgery decreased from 3.50% to 1.25% (p <0.0001). Mean hospital inflation-adjusted cost decreased from $10,478 to $8,367 (p <0.0001). Length of stay after the procedure decreased from 2.8 to 1.8 days (p <0.0001). Outcome of PCI continues to improve, with a decrease in coronary surgery and Q-wave myocardial infarction but with no significant change in mortality. This was accomplished while also decreasing costs and length of stay. Whether these favorable trends will continue remains to be seen.

Age Distribution↗
PubMed2001

Coil embolization for successful treatment of perforation of chronically occluded proximal coronary artery.

We describe a case of a coronary artery perforation involving the proximal right coronary artery that was successfully managed by percutaneous coil embolization. In the setting of a chronic coronary artery occlusion, this demonstrates the successful use of thrombogenic platinum alloy coils for a large proximal vessel perforation which has not been described previously.

Balloon Occlusion↗
PubMed2001

Balloon angioplasty.

Explore the source record for details and available documents.

Angioplasty, Balloon↗
PubMed2000

Measurement of endogenous nitric oxide production.

The measurement of exhaled pulmonary nitric oxide concentrations requires that contamination from the upper respiratory tract and inhaled gases be eliminated. This can be achieved with no risk in the clinical setting of intubated patients of all ages in the operating room or intensive care unit. Further modifications of the anesthetic/ventilatory circuit allow for accurate determination of tidal volume and minute ventilation.

Anesthesia, Inhalation↗
PubMed1999

Influence of age on outcome after percutaneous transluminal coronary angioplasty.

This study estimates the influence of age on outcomes (mainly survival) of 21,516 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) between 1980 and 1996. We prospectively analyzed the patients in 5 age groups: <50, 50 to 59, 60 to 69, 70 to 79, and > or =80 years old. During the in-hospital period after PTCA, mortality increased from 0.28% in patients aged <50 to 3.45% in patients aged > or =80; Q-wave myocardial infarction was not significantly associated with age, and the 2 older groups were referred less often to coronary artery bypass graft surgery. During follow-up, lasting up to 10 years, the hazard of death was significantly influenced by age; Q-wave myocardial infarction was influenced by age, although the magnitude of the effect was relatively small and of questionable clinical significance; and coronary artery bypass graft surgery was performed less often in the 2 older age groups. Additional PTCA was similarly performed among the age groups. Age, diabetes mellitus, systemic hypertension, heart failure class, angioplasty in graft vessel, number of coronary vessels narrowed, and previous myocardial infarction were predictors of death over the 10-year follow-up. Age was the most important correlate of death after PTCA, with a 65% increase in the hazard of death for each 10-year increase in age. Age has an independent effect on early and late survival after PTCA.

Age Distribution↗
PubMed1999

Nitric oxide production and absorption in trachea, bronchi, bronchioles, and respiratory bronchioles of humans.

Different volumes of dead-space gas were collected and analyzed for nitric oxide (NO) content, either immediately after inspiration or after a period of breath holding on clean air or NO mixtures. This allowed calculation of NO equilibrium, NO production, and NO absorption. In seven young, healthy, adult nonsmokers, the mean NO equilibrium values in parts per billion (ppb) were 56 +/- 11 (SE) in the trachea, 37 +/- 6 in the bronchi, 21 +/- 3 in the bronchioles, and 16 +/- 2 in the respiratory bronchioles. At any given NO concentration, the NO absorption rate (in nl/min) equaled the NO concentration (in ppb) times A (the absorption coefficient in l/min). A values (in l/min) were 0.11 +/- 0.01 in the trachea, 0.17 +/- 0. 04 in the bronchi, 0.66 +/- 0.09 in the bronchioles, and 1.35 +/- 0. 32 in the respiratory bronchioles. NO equilibrium concentrations and production rates in one 74-yr-old subject were three to five times as high as those found in the young subjects. Mouth equilibrium NO concentrations were 3 and 6 parts per million in two subjects who had oral production rates of 6 and 23 nl/min, respectively. In conclusion, production and absorption of NO occur throughout the first 450 ml of the airways.

Adult↗
PubMed1998

Usefulness of the substitution of nonangiographic end points (death, acute myocardial infarction, coronary bypass and/or repeat angioplasty) for follow-up coronary angiography in evaluating the success of coronary angioplasty in patients with angina pectoris.

Historically, restenosis after coronary angioplasty has been assessed angiographically at about 6 months. The desirability of avoiding routine follow-up angiography as well as the recognition that angiographic and clinical assessments are not necessarily the same has prompted greater interest in following patients clinically after angioplasty. Clinical restenosis has been defined as the composite of death, myocardial infarction, coronary surgery, or additional angioplasty within 6 months of the index procedure. Clinical restenosis was observed in 2,340 of 11,473 patients (20.4%). The mortality at 6 months was only 1%. Although there were somewhat more acute myocardial infarctions and coronary surgical procedures, the most frequent event was additional angioplasty. Angiographic restenosis was noted in 30% of patients without clinical restenosis and in 87% of patients with clinical restenosis (p < 0.0001). Patients with clinical restenosis were less likely to be women, had more systemic hypertension, diabetes mellitus, more severe angina originally, fewer prior myocardial infarctions, more multivessel and left anterior descending artery disease, more multisite procedures, more branch site procedures, and longer and tighter stenoses both before and after the procedure. The year of the procedure did not correlate with restenosis. Clinical restenosis is less common than angiographic restenosis and the most common event is additional angioplasty. Although clinical restenosis is rarely fatal, it does result in inconvenience and additional resource consumption.

Angina Pectoris↗
PubMed1998

Outcome of coronary bypass surgery versus coronary angioplasty in diabetic patients with multivessel coronary artery disease.

OBJECTIVES: This study sought to compare the outcome of percutaneous transluminal coronary angioplasty (PTCA) (n = 834) and coronary artery bypass graft surgery (CABG) (n = 1805) in diabetic patients with multivessel coronary disease from an observational database. BACKGROUND: There is concern about selection of revascularization in diabetic patients with multivessel coronary artery disease. METHODS: Data were collected prospectively and entered into a computerized database. Follow-up was by letter or telephone or additional events resulting in readmission. RESULTS: After CABG there were more in-hospital deaths (0.36% vs. 4.99%, p < 0.0001) and a trend toward more Q wave myocardial infarctions than after PTCA. Five- and 10-year survival rates were 78% and 45% after PTCA and 76% and 48% after CABG, respectively (p = 0.47). At 5 and 10 years, insulin-requiring patients had lower survival rates of 72% and 31% after PTCA and 70% and 48% after CABG, respectively (p = 0.54). Multivariate correlates of long-term mortality were older age, low left ventricular ejection fraction, heart failure and hypertension. In the total group, insulin requirement was a correlate of long-term mortality. For the total group, choice of therapy had a multivariate hazard ratio close to 1. In the insulin-requiring subgroup, the multivariate hazard ratio was 1.35 (95% confidence interval 1.01 to 1.79) for PTCA versus CABG. Corrected for baseline differences, 5- and 10-year survival rates were 68% and 36% after PTCA and 75% and 47% after CABG, respectively, in the insulin-requiring subgroup. Nonfatal events were more common after PTCA, especially additional revascularization. CONCLUSIONS: This study reveals a high incidence of events in diabetic patients and raises further questions about angioplasty in insulin-requiring diabetic patients with multivessel disease.

Aged↗
PubMed1998

Production and absorption of nitric oxide gas in the nose.

Some nitric oxide gas (NO) produced in the sinuses and nasal cavity is absorbed before leaving the nose. To measure production and absorption, we introduced NO at different concentrations into one nostril while sampling the NO leaving the opposite nostril with the soft palate closed. The quantity of NO gas produced in six normal subjects (amount leaving plus the amount absorbed) averaged 352 nl/min and was the same at gas flows ranging from 8 to 347 ml/min and at 10 l/min. An absorption coefficient A was calculated by dividing the amount of NO absorbed by the concentration leaving the nose. A ranged from 17 ml/min at a nasal gas flow of 8 ml/min to an A of 24 ml/min at a nasal gas flow of 347 ml/min. The calculated rates of production and absorption did not change when gas flow rate was increased, suggesting diffusion equilibrium. The amount of uptake of NO in the nasal mucosa can be explained by its solubility coupled with tissue and blood reactivity.

Absorption↗
PubMed1997

Directional coronary atherectomy (DCA): a report from the New Approaches to Coronary Intervention (NACI) registry.

Directional coronary atherectomy (DCA) with the Simpson coronary atherocath seeks to debulk rather than simply displace obstructive tissue and is a means of enlarging the stenotic coronary lumen. This report from the New Approaches to Coronary Intervention (NACI) registry describes the experience of 1,196 patients who underwent DCA as the sole treatment for either native vessel or vein graft lesions. Device success (post-DCA residual stenosis <50% and > or =20% improvement) was achieved in 87.8%, with a lesion success rate (postprocedural residual stenosis <50% and > or =20% improvement) of 94.0%. The mean resultant stenosis after all interventions (by core laboratory) was 19%. Significant in-hospital complications occurred in 2.8% of patients with DCA attempts, including death 0.6%, Q-wave myocardial infarction (MI) 1.5%, and emergent coronary artery bypass graft surgery (CABG) 2.8%. At 1-year follow-up, cumulative mortality was 3.6%, with repeat revascularization in 28% (repeat percutaneous transluminal coronary angioplasty, 20.1%; CABG, 10.6%). This reflected percutaneous or surgical revascularization of the original lesion (target lesion revascularization) in 22.6% of patients. Subgroup analysis showed a lower lesion success rate and an increased complication rate for unplanned use, vein graft treatment, and treatment of a de novo (vs a restenotic) lesion. Multivariate analysis shows that diabetes mellitus, unstable angina, treatment of a restenotic lesion, and greater residual stenosis after the initial procedure were independent predictors of the composite endpoint of death/Q-wave MI/target lesion revascularization by 1-year follow-up. Among these generally favorable acute and 1-year results, the NACI directional atherectomy data confirm the "bigger is better" hypothesis: that lesions with a lower residual stenosis after a successful procedure had significantly fewer target lesion revascularizations between 30 days and 1 year, with no increase in major adverse events.

Atherectomy, Coronary↗
PubMed1997

Stent placement compared with balloon angioplasty for obstructed coronary bypass grafts. Saphenous Vein De Novo Trial Investigators.

BACKGROUND: Treatment of stenosis in saphenous-vein grafts after coronary-artery bypass surgery is a difficult challenge. The purpose of this study was to compare the effects of stent placement with those of balloon angioplasty on clinical and angiographic outcomes in patients with obstructive disease of saphenous-vein grafts. METHODS: A total of 220 patients with new lesions in aortocoronary-venous bypass grafts were randomly assigned to placement of Palmaz-Schatz stents or standard balloon angioplasty. Coronary angiography was performed during the index procedure and six months later. RESULTS: As compared with the patients assigned to angioplasty, those assigned to stenting had a higher rate of procedural efficacy, defined as a reduction in stenosis to less than 50 percent of the vessel diameter without a major cardiac complication (92 percent vs. 69 percent, P<0.001), but they had more frequent hemorrhagic complications (17 percent vs. 5 percent, P<0.01). Patients in the stent group had a larger mean (+/-SD) increase in luminal diameter immediately after the procedure (1.92+/-0.30 mm, as compared with 1.21+/-0.37 mm in the angioplasty group; P<0.001) and a greater mean net gain in luminal diameter at six months (0.85+/-0.96 vs. 0.54+/-0.91 mm, P=0.002). Restenosis occurred in 37 percent of the patients in the stent group and in 46 percent of the patients in the angioplasty group (P=0.24). The outcome in terms of freedom from death, myocardial infarction, repeated bypass surgery, or revascularization of the target lesion was significantly better in the stent group (73 percent vs. 58 percent, P = 0.03). CONCLUSIONS: As compared with balloon angioplasty, stenting of selected venous bypass-graft lesions resulted in superior procedural outcomes, a larger gain in luminal diameter, and a reduction in major cardiac events. However, there was no significant benefit in the rate of angiographic restenosis, which was the primary end point of the study.

Aged↗
PubMed1997

Angioplasty or surgery for multivessel coronary artery disease: comparison of eligible registry and randomized patients in the EAST trial and influence of treatment selection on outcomes. Emory Angioplasty versus Surgery Trial Investigators.

The Emory Angioplasty versus Surgery Trial (EAST) showed that multivessel patients eligible for both percutaneous transluminal coronary angioplasty (PTCA) and coronary bypass surgery (CABG) had equivalent 3-year outcomes regarding survival, myocardial infarction, and major myocardial ischemia. Patients eligible for the trial who were not randomized because of physician or patient refusal were followed in a registry. This study compares the outcomes of the randomized and registry patients. Of the 842 eligible patients, 450 did not enter the trial. Their baseline features closely resembled those of the randomized patients and follow up was performed using the same methods. In the registry there was a bias toward selecting CABG in patients with 3-vessel disease (84%) and PTCA in patients with 2-vessel disease (54%). Three-year survival for the registry patients was 96.4%, which was better than the randomized patients, 93.4% (p = 0.044). Angina relief in the registry was equal for CABG and PTCA patients and was better for the PTCA registry (12.4%) than PTCA randomized patients (19.6%) (p = 0.079). Thus, the registry confirms that EAST is representative of all eligible patients and does not represent a low-risk subgroup. Since baseline differences were small, improved survival in the registry may be due to treatment selection. Physician judgment, even in patients judged appropriate for clinical trials, remains a potentially important predictor of outcomes.

Aged↗
PubMed1997

Short- and long-term outcome of narrowed saphenous vein bypass graft: a comparison of Palmaz-Schatz stent, directional coronary atherectomy, and balloon angioplasty.

Percutaneous treatment of saphenous vein graft (SVG) stenosis has been established as an alternative to repeat coronary artery bypass grafting. Intracoronary Palmaz-Schatz stent (PSS) and directional coronary atherectomy (DCA) have been suggested to provide better short- and long-term results than balloon angioplasty. Records of 840 patients with 931 SVG lesions treated with PSS (121 patients, 132 lesions), DCA (103 patients, 107 lesions), and balloon angioplasty (616 patients, 692 lesions) were reviewed. Inhospital and long-term outcome were compared among treated groups. The groups had similar clinical and angiographic baseline characteristics except for higher previously dilated grafts in the stent group and graft location among devices. Stent placement was angiographically successful in 99%, DCA in 95%, and balloon angioplasty in 93% of the lesions (p = 0.03). Quantitative angiography revealed a larger lumen diameter after procedure after PSS (3.2 mm) and DCA (3.1 mm) compared with 2.4 mm after balloon angioplasty (p = 0.0001). Angiographic complications (abrupt closure, severe dissections, or distal embolization) were evident in eight (6.1%) lesions after PSS placement, in 17 (15.9%) after DCA, and in 61 (8.8%) after balloon angioplasty. Serious in-hospital clinical complications (death, emergency coronary artery bypass grafting, or Q-wave myocardial infarction) were similar among devices. Survival rates were similar among the groups (p = 0.15). Repeat revascularization at follow-up was reported in 58 (60.4%) of patients after PSS, in 48 (51.1%) after DCA, and in 280 (49.4%) after balloon angioplasty. Correlates of additional revascularization at follow-up were older grafts, calcific lesions, previously dilated grafts, longer lesions, and patients with lower ejection fractions (odds ratio 1.06, 1.34, 1.43, 1.04, and 1.01, respectively). Correlates of mortality rate at follow-up were older patients, patients with lower ejection fractions, and distal embolization (odds ratio 1.04, 1.04, and 1.92, respectively). These data suggest that in patents with SVG stenosis the initial success and morbidity rates are similar when comparing PSS and DCA with balloon angioplasty. Although a larger lumen is obtained with PSS and DCA, patients who underwent balloon angioplasty had similar rates of cardiac events and requirements for additional procedures at follow-up.

Aged↗
PubMed1997

Exhalation of gaseous nitric oxide by rats in response to endotoxin and its absorption by the lungs.

Rats injected with a lipopolysaccharide endotoxin produce detectable concentrations of nitric oxide gas (NO) in the expired air within 60 min. The concentration of NO reaches a plateau at 3 h. Production of the NO is dose dependent on lipopolysaccharide, and at a dose of 1 mg/kg i.v., lipopolysaccharide alveolar concentrations of > 260 parts per billion are observed. NO synthase inhibitors suppress this NO production in response to endotoxin. Experiments were conducted to ascertain the site of origin of this NO and to measure the capacity of the lungs to absorb NO from alveolar air. Results indicate that the endotoxin-induced NO originates from within the lungs themselves and that the lungs have the capacity to absorb > 60% of NO that is presented to them. Lung tissues absorb approximately 44-47% of the NO load, blood carries away between 15 and 19%, while the remainder is exhaled in the expired air. It is proposed that the exhalation of NO might prove useful as an early biomarker for acute lung injury.

Animals↗
PubMed1996

"Bailout" coronary stenting in patients with a recent myocardial infarction.

Patients who underwent bailout intracoronary stenting within 7 days of a myocardial infarction had lower clinical and angiographic success rates and a higher incidence of emergent coronary artery bypass graft surgery than patients who underwent bailout stenting without a history of a recent myocardial infarction. In addition, there was a trend toward more cardiac events after discharge in patients who received stents after a recent myocardial infarction.

Aged↗
PubMed1996

Functional and binding characteristics of long-acting beta 2-agonists in lung and heart.

Salmeterol and formoterol, two new long-acting beta 2-agonists were equipotent (values of negative log molar concentration eliciting half-maximal effect [pD2] 9.2 +/- 0.03 and 8.9 +/- 0.03, respectively) in relaxing maximally contracted guinea pig tracheal spirals (histamine, 100 microM). Both agonists were 10 times more potent than L-isoproterenol and fenoterol and 100 times more potent than albuterol. L-Isoproterenol and fenoterol induced > 90% relaxation (percentage of maximal aminophylline relaxation). Formoterol and albuterol were equally efficacious. Formoterol was more efficacious (86 +/- 5%) than salmeterol (62 +/- 3%) or soterenol (59 +/- 3%). In minimally contracted tissues (10 microM histamine), agonist potencies increased 10-fold and relaxation was complete. In [125I]iodocyanopindolol-labeled bronchial membranes, formoterol and salmeterol induced high-affinity states of the beta 2-receptor (pKh 9.6 +/- 0.4 and 10.4 +/- 0.7, respectively), the former inducing a higher percentage (57 +/- 6 versus 28 +/- 4, p < 0.05). Only low-affinity binding (pKI) was observed when guanine nucleotide was present. pD2 values were similar to pKh values and relative efficacies significantly correlated with percentage of pKI sites. Formoterol and salmeterol were highly selective for the beta 2 versus beta 1-subtype (pKI values were 8.2 +/- 0.09 and 6.25 +/- 0.06 and 8.3 +/- 0.04 and 5.7 +/- 0.04, respectively). Albuterol (5.83 +/- 0.06 and 4.71 +/- 0.16) and fenoterol (6.33 +/- 0.07 and 5.67 +/- 0.05) were less selective. These results can explain the potencies and efficacies of salmeterol and formoterol in humans.

Adrenergic beta-Agonists↗