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Biomedical subjects

J Michael Duncan

Publications and source records attributed to J Michael Duncan.

8 recordsLinked to original sources
PubMed2006

Myocardial thievery: the coronary-subclavian steal syndrome.

Coronary-subclavian steal syndrome entails the reversal of blood flow in a previously constructed internal mammary artery coronary conduit, which produces myocardial ischemia. The most frequent cause of the syndrome is atherosclerotic disease in the ipsilateral, proximal subclavian artery. Although coronary-subclavian steal was initially reported to be rare, the increasing documentation of this phenomenon and its potentially catastrophic consequences in recent series suggests that the incidence of the problem has been underreported and that its clinical impact has been underestimated. We review the causes and background of coronary-subclavian steal; methods of preventing, diagnosing, and treating it; and the potential influence of various treatment regimens on long-term survival and the likelihood of late adverse events in patients with coronary-subclavian steal syndrome.

Anticoagulants↗
PubMed2006

Invited commentary.

Explore the source record for details and available documents.

Atrial Fibrillation↗
PubMed2005

Concomitant brachiocephalic and coronary artery disease: outcome and decision analysis.

BACKGROUND: In patients with coronary artery disease, concomitant brachiocephalic disease may affect outcome and influence decision making regarding operative staging, technique, and choice of conduit. METHODS: Eighty consecutive patients (mean age, 59.3 years; 60.0% male) with concomitant brachiocephalic and coronary artery disease were identified either before (group A, n = 48) or after (group B, n = 32) coronary artery bypass grafting. Patients who had symptomatic brachiocephalic and coronary artery disease before surgery underwent concomitant brachiocephalic reconstruction and coronary artery bypass grafting using either all-vein coronary conduits (n = 41) or vein-and-internal mammary artery conduits (n = 7). Patients who had coronary-subclavian steal syndrome after coronary artery bypass (group B, n = 32) underwent either surgical (n = 5) or endovascular (n = 27) brachiocephalic reconstruction only. RESULTS: All patients were asymptomatic after intervention. Operative mortality was 4.2% for group A and 3.1% for group B. The perioperative stroke rate was 2.1% for group A and 0% for group B. Actuarial 10-year freedom from specific events for group A was as follows: death 59.9 +/- 12.8%, brachiocephalic restenosis 100%, coronary-subclavian steal syndrome 100%, myocardial infarction 83.5 +/- 10.5%, stroke 82.1 +/- 9.9%, redo coronary artery bypass grafting 95.8 +/- 4.1%, other vascular operation 82.2 +/- 8.9%, and adverse cardiac outcome (death, redo coronary artery bypass grafting, or myocardial infarction) 52.9% +/- 13.2% (for patients with all-vein conduits) or 100% (for patients with vein-and-internal mammary artery conduits). At midterm follow-up (mean, 2.92 years), both the surgical and the endovascular treatment subgroups of group B had 100% brachiocephalic patency. CONCLUSIONS: Long-term results in a limited population support continued evaluation of concomitant brachiocephalic reconstruction and coronary artery bypass grafting with use of the internal mammary artery conduit in an attempt to improve late survival in patients with concomitant disease. The excellent midterm brachiocephalic patency after either surgical or endovascular treatment of patients with coronary-subclavian steal syndrome supports continued evaluation of both methods.

Adult↗
PubMed2005

Brachiocephalic reconstruction II: operative and endovascular management of single-vessel disease.

OBJECTIVE: Although the surgical management of brachiocephalic disease is well established, evolving endovascular techniques present new options for treatment. We explored the potential benefits and drawbacks of these interventions in terms of outcome. METHODS: From 1966 to 2004, 391 consecutive patients (43.7% male; mean age, 61.9 years) with single-vessel brachiocephalic disease were treated with either operative bypass (group A; n = 229) or percutaneous transluminal angioplasty and stenting (group B; n = 162). RESULTS: All patients were asymptomatic after surgery or endovascular intervention. Group A and group B had similar operative mortality (0.9% vs 0.6%) and stroke (1.3% vs 0%) rates. However, 5 years after the procedure, group A had significantly better freedom from graft or intervention failure (92.7% +/- 2.1%) than did group B (83.9% +/- 3.7%; P = .03, Kaplan-Meier analysis; P = .001, Cox regression analysis). At 10 years, group A had the following rates of actuarial freedom from specific events: death, 73.7% +/- 4.6%; myocardial infarction, 84.2% +/- 3.6%; stroke, 91.4% +/- 3.4%; graft failure, 88.1% +/- 3.3%; coronary revascularization, 69.8% +/- 5.1%; and other vascular operation, 70.7% +/- 4.6%. Endovascular intervention involved less initial cost (mean savings, $8787 per procedure), was less invasive, and did not necessitate general anesthesia. On satisfaction questionnaires, 96.5% of patients receiving an endovascular intervention and 95.1% of patients receiving operative bypass for single-vessel brachiocephalic disease subjectively rated their treatment as "good" or "very good." CONCLUSIONS: Operative bypass and endovascular intervention for single-vessel brachiocephalic disease are both associated with acceptably low operative morbidity and mortality. Operative bypass produces significantly better mid-term freedom from graft or intervention failure than endovascular intervention and produces excellent long-term freedom from failure. Endovascular intervention offers tangible benefits regarding cost, level of invasiveness, and subjective patient satisfaction. Undetermined are the differences between the procedures regarding long-term durability, patterns of failure, efficacy as an adjunct to coronary artery bypass grafting, need for anticoagulation, efficacy as treatment for complex (multivessel) disease, and long-term cost.

Adult↗
PubMed2005

Brachiocephalic reconstruction I: operative and long-term results for complex disease.

OBJECTIVES: Complex brachiocephalic disease involves multiple vessels and is frequently associated with multisystem atherosclerosis. We reviewed surgical outcome and examined the impact of this problem on decision making regarding operative staging, technique, and choice of conduit. METHODS: Between 1966 and 2000, 157 consecutive patients (mean age, 54.0 years; 48.4% male) with innominate artery or multivessel brachiocephalic disease underwent operative reconstruction using either a transthoracic approach (group A, n = 113) or a less invasive, extrathoracic approach (group B, n = 44). Reconstruction required multiple distal anastomoses in 70 patients (44.6%), concomitant coronary artery bypass grafting (CABG) in 37 patients (23.6%), and concomitant carotid endarterectomy (CEA) in 26 patients (16.6%). RESULTS: No significant differences were found between group A and group B when operative mortality (2.7% vs 2.3%) and stroke rates (2.7% vs 6.8%) were analyzed. However, 10 years after surgery, freedom from graft failure was significantly better in group A (94.4% +/- 4.4%) than in group B (60.3% +/- 13.4%) ( P = .002). Freedom from graft failure was adversely affected by nonaortic inflow ( P = .002) and axillo-axillary cervical grafts ( P = .0001). Mortality and stroke rates for subgroups having multiple distal anastomoses (2.9%, 2/70 and 4.3%, 3/70), concomitant CABG (5.4%, 2/37 and 0, 0/37), and concomitant CEA (3.8%, 1/26 and 3.8%, 1/26) were similar to those of other patients. For the entire patient group, 10-year rates of actuarial freedom from specific events were death, 68.8% +/- 6.0%; myocardial infarction, 86.7% +/- 4.5%; stroke, 87.0% +/- 4.4%; coronary revascularization, 88.0% +/- 3.6%, and other vascular operation, 79.9% +/- 4.4%. CONCLUSIONS: Transthoracic arch reconstruction for complex brachiocephalic disease can be done with acceptably low morbidity and mortality similar to those of a less invasive, extrathoracic approach. Furthermore, the transthoracic approach is associated with significantly better long-term freedom from graft failure, possibly because it preserves aortic inflow to the great vessels. Nonetheless, the high frequency of late events in this relatively young patient population reflects the presence of multisystem atherosclerosis and suggests the need for close follow-up and lifestyle modification.

Adult↗
PubMed1981

Left ventricular aneurysm: Twenty-year surgical experience with 1572 patients at the Texas Heart Institute.

From January 1958 through December 1979, 1572 patients underwent surgery for left ventricular aneurysm (LVA) in our institution. The series included 1365 men and 207 women, with a ratio of 6.5:1. Ages ranged from 25 to 79 years, with a mean of 54.7 years. Most patients were in NYHA functional Class III or IV, and all had sustained at least one documented myocardial infarction. During the first decade, LVA resection alone was performed, but after the advent of aortocoronary bypass (ACB) surgery, the majority of patients underwent ACB along with LVA resection. Some required additional septoplasty, mitral valve replacement, annuloplasty, or aortic valve replacement. In all groups, the mortality was higher for women than for men. Early deaths were due primarily to acute or progressive myocardial failure secondary to recurrent myocardial infarction. Follow-up information for 6 months to 8 years was obtained by means of questionnaires submitted to patients and referring physicians. Of 475 patients who underwent LVA resection and ACB and who responded, 92.2% were either improved or asymptomatic.

Journal Article↗