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Biomedical subjects

H L Lazar

Publications and source records attributed to H L Lazar.

At least 19 recordsLinked to original sources

Glucose-insulin-potassium solutions improve outcomes in diabetics who have coronary artery operations.

BACKGROUND: This study was undertaken to determine whether glucose-insulin-potassium (GIK) would improve myocardial performance and limit morbidity after coronary artery bypass grafting in diabetic patients. METHODS: Forty consecutive coronary artery bypass grafting patients with medically treated diabetes mellitus were prospectively randomly assigned to either a GIK group (n = 20; 500 mL D5W + 80 U regular insulin + 40 mEq KCl 30 mL/hour) or a no-GIK group (n = 20; D5W at 30 mL/hour). The GIK was begun at anesthetic induction and continued for 12 hours postoperatively. RESULTS: Patients treated with GIK had higher postoperative cardiac indices (2.88 +/- 0.50 versus 2.20 +/- 0.39 L/minute per square meter; p < 0.0001), lower inotrope scores (0.40 +/- 0.68 versus 1.25 +/- 1.44; p = 0.05), less weight gain (5.80 +/- 3.76 versus 13.85 +/- 6.52 pounds; p < 0.0001), and had shorter times of ventilator support (8.35 +/- 2.60 versus 13.45 +/- 7.33 hours; p = 0.0128). They had a significantly lower prevalence of atrial fibrillation (15% versus 60%; p = 0.003), and shorter hospital stays (6.70 +/- 1.52 versus 10.15 +/- 6.62 days; p = 0.02). CONCLUSIONS: Substrate enhancement with GIK in diabetic patients improved myocardial performance and resulted in faster recovery after coronary artery bypass grafting.

Aged↗

Total complement inhibition: an effective strategy to limit ischemic injury during coronary revascularization on cardiopulmonary bypass.

BACKGROUND: Activation of complement during revascularization of ischemic myocardium accentuates myocardial dysfunction. Soluble human complement receptor type 1 (sCR1) is a potent inhibitor of complement, as are heparin-bonded (HB) cardiopulmonary bypass (CPB) circuits. This study sought to determine whether total complement inhibition with the combination of sCR1 and HB-CPB limits damage during the revascularization of ischemic myocardium. METHODS AND RESULTS: In 40 pigs, the second and third diagonal coronary arteries were occluded for 90 minutes, followed by 45 minutes of cardioplegic arrest and 180 minutes of reperfusion. In 10 pigs, sCR1 (10 mg/kg) was infused 5 minutes after the onset of coronary occlusion (sCR1), 10 received HB-CPB only (HB-CPB), 10 received sCR1 and HB-CPB (sCR1+HB), and 10 received neither sCR1 or HB-CPB (unmodified). Addition of sCR1 to the HB group resulted in less myocardial tissue acidosis (DeltapH = -0.72+/-0.03 for unmodified; -0.46+/-0.05 for HB; -0.18+/-0.04 for sCR1; -0.13+/-0.01 for sCR1+HB), better recovery of wall motion scores (4 = normal to -1 = dyskinesia; 1.67+/-0.17 for unmodified; 2.80+/-0.08 for HB; 3.35+/-0.10 for sCR1; 3.59+/-0.08 for sCR1+HB), less lung water accumulation (5.46+/-0.28% for unmodified; 2.39+/-0.34% for HB; 1.22+/-0.07% for sCR1; 1.24+/-0.13% for sCR1+HB), and smaller infarct size (area necrosis/area risk = 44.6+/-0.7% for unmodified; 33.2+/-1.9% for HB; 19.0+/-2.4% for sCR1; 20+/-1.0% for sCR1+HB) (P<0.05 versus unmodified; P<0.05 versus unmodified and HB groups). CONCLUSIONS: Total complement inhibition with sCR1 and sCR1+HB circuits optimizes recovery during the revascularization of ischemic myocardium.

Animals↗

Decreased incidence of arterial thrombosis using heparin-bonded intraaortic balloons.

BACKGROUND: This experimental study sought to determine whether heparin-bonding of intraaortic balloons (IAB) would decrease the incidence of arterial thrombosis in the absence of systemic heparinization. METHODS: In 25 adult pigs, a 9F, 40-mL IAB was inserted into the femoral artery and positioned just below the takeoff of the left subclavian artery for 9 hours. Five animals received systemic heparin, 10 animals had no heparin, and another 10 animals received no heparin but the IAB was heparin-bonded (Duraflo II). Thrombus formation was assessed using a numerical scoring system (0 = no thrombosis to 3 = thrombus >5 cm or evidence of luminal compromise). RESULTS: Animals receiving heparin and heparin-bonded IAB had no thrombus formation around the IAB (mean +/- SE; 0 +/- 0.00 heparin versus 1.55 +/- 0.29 no heparin versus 0 +/- 0.00 heparin-bonded; p < 0.005), at the insertion site (0 +/- 0.00 heparin versus 1.55 +/- 0.29 no heparin versus 0 +/- 0.0 heparin-bonded; p < 0.005), and in the distal femoral artery (0 +/- 0.00 heparin versus 2.00 +/- 0.23 no heparin versus 0 +/- 0.00 heparin-bonded; p < 0.005). CONCLUSIONS: Heparin-bonding of the IAB significantly decreases thrombus formation in the absence of systemic heparinization.

Animals↗

Effect of gender on postoperative outcomes and hospital stays after coronary artery bypass grafting.

BACKGROUND: Compared to men, women undergoing coronary artery bypass grafting appear to have a higher morbidity and mortality, particularly in the perioperative period. This study was designed to answer the questions of whether such differences in clinical outcomes between men and women still exist with improvements in surgical techniques and determine whether it is gender or associated comorbid conditions in women that lead to higher morbidity. METHODS: An analysis of a single center's contemporary experience (1994 to 1997) of 1,743 consecutive patients undergoing primary coronary artery bypass grafting was performed. Only reoperations were excluded. Data were collected prospectively and presented as mean +/- standard deviation (p<0.05). RESULTS: Women represented 30.0% of patients. Compared with men, women were older (68.4 versus 63.8 years; p<0.05), and had more urgent surgical interventions (70.0% versus 56.7%; p<0.05), a higher incidence of diabetes (42.1% versus 26.7%; p<0.05), hypertension (82.0% versus 73.9%; p<0.05), lower body surface area (1.73+/-0.18 m2 versus 2.03+/-0.19 m2; p<0.05), and hematocrit (31.7%+/-3.9% versus 36.2%+/-3.9%; p<0.05). Ejection fraction, incidence of previous myocardial infarction, chronic obstructive pulmonary disease, left main (LM) disease, renal insufficiency, extent of coronary disease, and preoperative intraaortic balloon pump were similar. Women received fewer arterial grafts (91.0% versus 95.5%; p<0.05) and distal anastomoses (3.31+/-0.88 versus 3.49+/-0.94 p<0.05). Despite these differences, there were no statistical differences in the incidence of postoperative death (1.5% versus 1.0%), myocardial infarction (0.6% versus 0.6%), or cerebrovascular accident/transient ischemic attack (1.1% versus 0.4%) between men and women. Women had a higher inotropic support (10.2% versus 4.4%; p<0.05) and longer hospital stays (7.3+/-5.7 days versus 6.3+/-4.2 days; p<0.05). Using multivariate analysis, female gender was not an independent predictor of death or postoperative complications but was a predictor of length of hospital stay, use of arterial grafts, and extent of coronary revascularization. CONCLUSIONS: After accounting for differences in their risk variables, the incidences of death, perioperative myocardial infarction and cerebrovascular accident/ transient ischemic attack after coronary artery bypass grafting in women and men were not statistically significant. Perioperative complications are related to comorbid risk factors but not to female gender itself. Further studies are warranted.

Age Factors↗

Improved clinical outcomes after operation of the proximal aorta: a 10-year experience.

BACKGROUND: This study evaluated the impact of recent advances (particularly noninvasive diagnosis, retrograde cerebral perfusion, heparin-bonded circuits, and use of collagen-impregnated grafts and antifibrinolytic agents) on clinical outcomes of patients undergoing proximal aortic operations. METHODS: One hundred eight consecutive patients undergoing 111 proximal aortic operations over 10 years were studied. The cohort was divided into two groups: early, 1987 to 1993 and late, 1994 to 1997. RESULTS: Baseline patients profiles, indications for operation (aneurysm, 66 patients; dissection, 45 patients), priority of the operation, and surgical procedures were comparable for both groups. Mortality and morbidity for the entire cohort were 13.5% (15 of 111) and 66% (73 of 111), respectively. Compared with the early group, the late group was characterized by significantly higher use of noninvasive diagnostic modalities (69% versus 10%), exclusive use of heparin-bonded circuits and collagen-impregnated grafts (100% versus 0% for both), use of antifibrinolytic agents (79% versus 8%), and the introduction of retrograde cerebral perfusion (43% versus 0%) (p<0.00001 for all). These changes in practice were associated with a substantial decrease in operative mortality (26% [13 of 49] versus 3% [2 of 62], p = 0.001), overall morbidity (77% [38 of 49] versus 56% [35 of 62], p = 0.02), blood transfusions (55.6+/-48 donor units versus 29.3+/-35 donor units, p = 0.003), and a shorter hospital stay (21.6+/-31 days versus 12.1+/-15 days, p = 0.07). Average long-term follow-up for 99% (107 of 108) of patients was 29.6+/-30 months (1 to 120 months). Ten-year actuarial survival was 57.3%+/-8% with 93% being in New York Heart Association functional class I or II. CONCLUSIONS: Recent advances, particularly noninvasive diagnosis and improved operative management, have led to a substantial reduction in mortality and morbidity after proximal aortic operation. Improved short- and long-term outcomes were achieved both in acute dissection and aneurysm procedures, although patients remain at risk for long-term distal aortic complications.

Adult↗

Favorable impact of stents after emergent coronary artery bypass for failed angioplasty.

BACKGROUND: This study was undertaken to determine the impact of the use and availability of coronary stents on outcomes in patients requiring emergent coronary artery bypass graft (CABG) surgery following a failed percutaneous transluminal coronary angioplasty (PTCA). METHODS: Patients were divided into two groups based on the year of their CABG for a failed PTCA and the availability of stents: group 1, 1992 to 1994, stents not available (n = 34); and group 2, 1995 to 1997, stents available (n = 26). RESULTS: CABG patients in the group where stents were not available were more likely to have had an abrupt coronary occlusion (26 of 34 versus 3 of 26; p < 0.0001) and less likely to have had a dissection (8 of 34 versus 23 of 26; p < 0.0001) as their indication for emergent CABG. Patients in the stent era had a lower incidence of perioperative myocardial infarction (5 of 26 versus 17 of 34; p < 0.01) and a decreased mortality rate (0 of 26 versus 6 of 34; p < 0.03). In the 9 patients where stents were employed, patency of the lumen was restored in 8 patients and there was only 1 myocardial infarction. CONCLUSIONS: Stents have had a favorable impact on patients requiring an emergent CABG following a failed PTCA.

Aged↗

Accelerated allograft degeneration after aortic valve endocarditis.

Early calcification of aortic allografts is usually seen in children less than 3 years of age. We describe a case of a 22-year-old intravenous drug user who developed calcific aortic valve stenosis less than 3 years after an allograft root replacement for endocarditis.

Adult↗

Improved clinical outcomes in patients undergoing coronary artery bypass grafting with coronary endarterectomy.

BACKGROUND: Coronary artery bypass grafting (CABG) with coronary endarterectomy (CE) has been associated with increased morbidity and mortality. We sought to evaluate the impact of recent advances in operative and perioperative management on outcomes after CE. METHODS: One hundred fifty-one consecutive patients undergoing first-time CABG with CE between 1991 and 1997 were compared with a concurrent group of 757 patients undergoing CABG without CE (Control). RESULTS: Age, gender, left ventricular ejection fraction, percent nonelective were similar in both groups. Compared with control, the CE group had a higher incidence of hypertension (80% versus 71%, p = 0.02), diabetes (42% versus 32%, p = 0.01), prior myocardial infarction (MI) (68% versus 59%, p = 0.05), peripheral vascular disease (36% versus 16%, p < 0.001), renal failure (15% versus 4%, p < 0.001), and three-vessel coronary disease (81% versus 70%, p = 0.007), resulting in higher Society of Thoracic Surgeons database predicted mortality (4.9+/-5.9% versus 3.9+/-4.6%, p = 0.05). Despite the higher risk profile of the CE group, hospital mortality (CE 2.0%, Control 1.2%) and the incidence of major complications such as cerebrovascular accident (CVA) (0.7% versus 1.5%), major respiratory complications (8% versus 5%), and postoperative MI (3% versus 1.4%) were similar between the groups (all p = NS). In a multiple logistic regression analysis, prolonged cardiopulmonary bypass time was an independent predictor of postoperative MI (odds ratio 1.2, CI 1.05 to 1.39, p < 0.01) and the use of heparin-bonded cardiopulmonary bypass circuits of reduced MI rate (odds ratio 0.25, CI 0.08 to 0.76, p < 0.01). Mean follow-up for 94% of patients was 30+/-19 months (range 1 to 83 months). Five-year survival after CE was 70+/-5%, with 96% of patients in Canadian Cardiovascular Society class I/II. CONCLUSIONS: In a contemporary series of carefully selected patients, mortality and major complications after CE are now similar to CABG without CE. CE itself is not an independent predictor of postoperative MI. Functional class of hospital survivors is excellent.

Aged↗

Effect of anticoagulation protocol on outcome in patients undergoing CABG with heparin-bonded cardiopulmonary bypass circuits.

BACKGROUND: We have demonstrated that the use of heparin-bonded cardiopulmonary bypass circuits (HBCs) combined with a lower anticoagulation protocol as an adjunct to an integrated blood conservation strategy decreases the incidence and magnitude of homologous transfusion and improves clinical outcome in patients undergoing primary coronary artery bypass grafting. It is not known whether it is the lower anticoagulation protocol that influences outcome in patients treated with HBCs. Furthermore, the thrombogenic risk of using lower anticoagulation with HBCs still is debated. METHODS: To answer these questions, a prospective randomized study was conducted in which 244 patients undergoing primary coronary artery bypass grafting were treated with HBCs and randomized to undergo either a full (activated clotting time, > 450 seconds) or a lower (activated clotting time, > 250 seconds) anticoagulation protocol. In addition to clinical outcome, levels of thrombin generation markers during and after cardiopulmonary bypass were assessed in a consecutive subset of 58 patients (full anticoagulation profile = 28, lower anticoagulation profile = 30) by measuring thrombin-antithrombin complexes and prothrombin fragment 1.2. Levels of these markers also were correlated with the activated clotting time during cardiopulmonary bypass. RESULTS: Preoperative and intraoperative risk profiles and other characteristics were similar in both groups, with more than 60% of patients undergoing nonelective operation. Compared with the full anticoagulation protocol group, patients in the lower anticoagulation protocol group were less likely to require blood products (24.2% versus 35.8%, respectively; p = 0.047) and received substantially fewer homologous donor units (0.50 +/- 0.92 versus 1.08 +/- 2.10 U, respectively; p = 0.005). Clinical outcomes were uniformly outstanding (but similar) in both treatment groups, with a modest reduction in the length of the hospital stay in the lower anticoagulation protocol group (5.26 +/- 1.23 versus 5.63 +/- 1.73 days, respectively; p = 0.05). The use of HBCs with a lower anticoagulation protocol was not associated with any adverse clinical events. Thrombin generation increased during cardiopulmonary bypass in both treatment groups, but was unrelated to the anticoagulation protocol or the activated clotting time (r2 = 0.03). No differences between the full and lower anticoagulation protocol groups were noted in the number of microemboli detected by transcranial Doppler analyses during cardiopulmonary bypass (n = 40) or in the postoperative neurologic and neuropsychologic outcomes (n = 30). CONCLUSIONS: This study definitively demonstrates that, when used appropriately, patients who are treated with HBCs and a lower anticoagulation protocol have a lower incidence and magnitude of homologous transfusion and are not at any added risk for clinical, hematologic (thrombin-antithrombin complex and fragment 1.2 measurements), or microscopic (transcranial Doppler analyses) thromboembolic complications or for neurologic or neuropsychologic deficits.

Aged↗

Reduction of allogeneic blood transfusions after open heart operations by lowering cardiopulmonary bypass prime volume.

BACKGROUND: Despite recent advances in blood conservation techniques, up to 30% to 80% of patients undergoing open heart operations require allogeneic blood transfusions. A prospective, randomized study was performed to test the effect of lowering cardiopulmonary bypass prime volume (as an additional component of an integrated blood conservation strategy) on clinical outcome and allogeneic blood transfusion. METHODS: One hundred fourteen patients undergoing open heart operations were randomized to either full prime (FP) volume (1,400 mL of Plasmalyte solution) or reduced prime (RP) volume (600 to 800 mL). The reduction of prime volume was achieved by slowly draining the cardiopulmonary bypass circuit into a cell-saving device before the initiation of bypass. Firm transfusion thresholds were observed. RESULTS: There were no significant differences between the groups with respect to baseline characteristics, body surface area, type and urgency of the procedures, perfusion technique, and hematologic profile. Mortality (FP, 1.7%; RP, 0%; p approximately 1.0) and overall morbidity (FP, 28.1%; RP, 22.8%; p = 0.53) were similar. However, transfusion requirements were significantly lower in the RP group: total donor exposure, 3.8 +/- 10.1 versus 1.0 +/- 2.4 units (p = 0.044); percentage of patients transfused, 54% (n = 31) versus 35% (n = 20) (p = 0.036). Twenty-four-hour chest tube drainage was similar: 455 +/- 223 mL for FP versus 472 +/- 173 mL for RP (p = 0.66). The lowest hematocrit on bypass was significantly higher in the RP group: 29.3% +/- 4% versus 26.3% +/- 5.3% (p = 0.009). CONCLUSIONS: Lowering cardiopulmonary bypass prime volume resulted in a significant decrease in allogeneic blood product use. Because postoperative 24-hour chest tube drainage was similar in both groups, and hematocrit during bypass was higher in the RP group, the reduction in allogeneic blood transfusions appears to be related to a decrease in prime-induced hemodilution. This technique is effective, simple, and safe. It therefore should be strongly considered for patients undergoing operations using normothermic or near-normothermic cardiopulmonary bypass who are at high risk for allogeneic blood transfusion.

Aged↗

Soluble complement receptor type I limits damage during revascularization of ischemic myocardium.

BACKGROUND: This study was undertaken to determine whether suppression of complement activation with soluble human complement receptor type I reduces myocardial damage during the revascularization of ischemic myocardium. METHODS: In 20 pigs, the second and third diagonal coronary arteries were occluded for 90 minutes, followed by 45 minutes of cardioplegic arrest and 180 minutes of reperfusion. In 10 pigs, soluble human complement receptor type I (10 mg/kg) was infused over 30 minutes before the period of coronary occlusion; 10 other pigs received no soluble human complement receptor type I. Complement activation was measured by total hemolytic complement activity (expressed as a percentage of preischemic values). Ischemic damage was assessed by changes in myocardial tissue pH, wall motion scores (range, 4=normal to -1=dyskinesia), and infarct size (area of necrosis versus area at risk). RESULTS: After 180 minutes of reperfusion, hearts treated with soluble human complement receptor type I had significantly less complement activation than nontreated hearts (1.1%+/-0.09% versus 7.8%+/-0.04%, respectively; p < 0.002), less myocardial acidosis (-0.41+/-0.03 versus -0.72+/-0.03, respectively; p < 0.0001), higher wall motion scores (3.1+/-0.09 versus 1.67+/-0.16, respectively; p < 0.0001), and smaller infarct size (24.6%+/-2.0% versus 41%+/-1.3%, respectively; p < 0.0001). CONCLUSIONS: Complement inhibition with soluble human complement receptor type I significantly limits ischemic damage during the revascularization of acutely ischemic myocardium.

Acidosis↗

Extubation of the patient after a difficult intubation.

A case of a difficult intubation in a heavy smoker requiring reoperative coronary artery bypass grafting is presented. A technique is described to extubate patients with marginal pulmonary function and a difficult intubation using airway exchange catheters.

Akathisia, Drug-Induced↗

Coronary artery bypass grafting in patients with cerebrovascular disease.

The incidence of carotid artery disease in patients undergoing coronary artery bypass grafting appears to be increasing as our population ages. The optimal treatment for these high-risk patients with concomitant carotid and coronary artery disease remains controversial. This review focuses on the management of patients with coexistent carotid and coronary arteriosclerosis. The significance and management of the patient with an asymptomatic carotid stenosis in patients undergoing coronary artery bypass grafting and the role of combined coronary artery bypass grafting and carotid endarterectomy in these patients will be discussed.

Brain↗

Comparison of risk profile and outcomes in patients undergoing surgical and catheter-based revascularization.

BACKGROUND: The effects of the randomized revascularization trials and improved strategies and techniques for coronary artery bypass graft (CABG) surgery and percutaneous transluminal catheter-based revascularization (PTCR) on current patient selection and clinical outcomes are unknown. METHODS: We evaluated a concurrent, contemporary (1995 to 1997), and consecutive group of patients undergoing CABG (n = 982) or PTCR (n = 939) in a single institution that participated in the Bypass Angioplasty Revascularization Investigation (BARI) trial. Results are presented as percent or mean +/- SD. Compared to PTCR, patients undergoing CABG were older (66.2+/-10.7 vs. 62.0+/-11.8 years, p<0.05) with a higher incidence of hypertension (73.3% vs. 52.4%, p<0.05), diabetes (32.5% vs. 23.1%, p<0.05), active smoking (67.8% vs. 27.2%, p<0.05), prior myocardial infarction (MI)(66.8% vs. 28.5%, p<0.05), peripheral vascular disease (19.8% vs. 7.7%, p<0.05), prior cerebrovascular accident (CVA)/transient ischemic attack (TIA) (6.4% vs. 2.8%, p<0.05), and a lower ejection fraction (48.7%+/-14.5% vs. 55.3%+/-11.7%, p<0.05). The presenting functional class and incidence of female gender were similar for both revascularization strategies. RESULTS: Compared to patients undergoing CABG, those undergoing PTCR were more likely to have single or two vessel coronary artery disease (88.6% vs. 23.1%, p<0.001) and had fewer vessels revascularized per patient (1.08+/-0.30 vs. 3.5+/-0.98, p<0.001). Outcomes were comparable for CABG and PTCR with a similar incidence of death (1.0% vs. 0.9%, NS), renal insufficiency (0.7% vs. 0.6%, NS), and CVA/TIA (0.9% vs. 0.3%, NS). Patients undergoing CABG had a higher incidence of pulmonary complications (5.2% vs. 1.0%, p<0.05), a lower incidence of periprocedural MI (1.1% vs. 4.1%, p<0.05) and major complication (5.9% vs. 9.4%, p<0.05), but longer hospital stays (6.5+/-5.1 vs. 3.1+/-2.6 days, p<0.05). CONCLUSIONS: Despite higher clinical and angiographic risk profiles in patients undergoing CABG, clinical results, morbidity, and mortality were comparable to those of PTCR. With evolving techniques, continued reevaluation of indications and outcomes are necessary.

Aged↗

Beneficial effects of angiotensin-converting enzyme inhibitors during acute revascularization.

BACKGROUND: This experimental study was undertaken to determine whether using angiotensin-converting enzyme inhibitors during surgical revascularization of acutely ischemic myocardium would improve wall motion and limit infarct size. METHODS: Twenty pigs underwent 90 minutes of occlusion of the second and third diagonal arteries followed by 45 minutes of cardioplegic arrest and 180 minutes of reperfusion. In 10 animals, the angiotensin-converting enzyme inhibitor enalaprilat (0.05 mg/kg) was infused intravenously during coronary occlusion; 10 other animals received no angiotensin-converting enzyme inhibitors. Ischemic damage was assessed by the number of cardioversions required for ventricular tachycardia or fibrillation; wall motion scores using echocardiography (4=normal to -1=dyskinesia); and infarct size using histochemical staining. Epicardial coronary artery vasomotor function was assessed using standard organ chamber methodology. RESULTS: Enalaprilat-treated hearts had the least amount of ventricular irritability (0.84+/-0.24 versus 2.77+/-0.22 cardioversions; p < 0.01), the best recovery of wall motion score (3.20+/-0.15 versus 1.52+/-0.07; p < 0.0001), and the lowest infarct size (22.6%+/-1.4% versus 37.7%+/-3.0%; p < 0.001). Endothelium-independent relaxation was preserved in all hearts; however, endothelium-dependent relaxation was impaired in both groups. CONCLUSIONS: Angiotensin-converting enzyme inhibitors reduce myocardial damage during surgical revascularization of acutely ischemic myocardium.

Angiotensin-Converting Enzyme Inhibitors↗