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Biomedical subjects

A A Bert

Publications and source records attributed to A A Bert.

At least 19 recordsLinked to original sources
PubMed2001

A beta-blocker, not magnesium, is effective prophylaxis for atrial tachyarrhythmias after coronary artery bypass graft surgery.

OBJECTIVE: To evaluate magnesium as a sole or adjuvant agent with currently used prophylactic drugs in suppressing postoperative atrial tachyarrhythmias (POAT) after coronary artery bypass graft (CABG) surgery. DESIGN: Single-center prospective, randomized clinical trial. SETTING: University hospital. PARTICIPANTS: Patients (n = 400) undergoing CABG surgery. INTERVENTIONS: Patients were randomized among 6 prophylaxis regimens: (1) control (no antiarrhythmics), (2) magnesium only, (3) digoxin only, (4) magnesium and digoxin, (5) propranolol only, and (6) magnesium and propranolol. Patients randomized to a regimen including magnesium received 12 g given during 96 hours postoperatively. Patients in a digoxin regimen received 1 mg after cardiopulmonary bypass and 0.25 mg daily. Patients in a propranolol regimen received 1 mg intravenously every 6 hours until able to take 10 mg orally 4 times a day. Prophylaxis regimens were discontinued after 4 days postoperatively. MEASUREMENTS AND MAIN RESULTS: The primary outcome was a sustained POAT or discharge from the hospital. Control patients had an incidence of POAT (38%) not significantly different from patients in magnesium-only (38%), digoxin-only (31%), and magnesium with digoxin (37%) regimens. Patients treated with propranolol had a significant reduction in POAT. Nearly identical POAT rates in the propranolol-only (18%) and propranolol with magnesium (19%) groups support the lack of efficacy of magnesium in this trial. Study design allowed analysis of and showed a beta-blocker withdrawal effect in addition to suppressive benefit of postoperative beta-blockers. CONCLUSION: beta-Blocker prophylaxis is indicated to reduce the incidence of POAT in CABG surgery patients and to prevent a beta-blocker withdrawal effect in patients receiving these medications preoperatively. Digoxin and magnesium as sole or adjuvant agents do not offer suppressive or ventricular rate reduction benefits in POAT.

Adrenergic beta-Antagonists↗
PubMed2000

Reproducible echocardiography in juvenile sheep and its application in the evaluation of a pulmonary valve homograft implant.

Increased use of the ovine animal model in cardiovascular surgical research has created a salient need for standardized echocardiography techniques. To demonstrate a reproducible image in this species and confirm the validity of echocardiography as a diagnostic tool, we implanted 10 sheep with a pulmonary valve homograft and monitored them through weekly echocardiographic examinations until 20 weeks after implantation. We obtained good images from the left cranial and the left caudal transducer windows without needing to sedate the animals. Sedated sheep yielded adequate views from the right apical window. Echocardiographic data on the implanted homografts (including functional capacity, presence of calcification, and hemodynamic information and measurements), completely agreed with the results of the post-explantation examinations.

Animals↗
PubMed1999

Veno-arterial modified ultrafiltration in children after cardiopulmonary bypass.

A method of performing veno-arterial modified ultrafiltration is described that utilizes conventional blood flow through the aortic and venous cannulae. A dual-pump blood cardioplegia console is adapted to aspirate blood from the cardiopulmonary bypass venous line. The blood is ultrafiltered, sent through the cardioplegia heat exchanger, and returned to the aorta via the cardioplegia needle. Veno-arterial modified ultrafiltration has produced no visual evidence of air entrainment in the cardiopulmonary arterial line. This method allows the immediate resumption of cardiopulmonary bypass without the need for the surgeon to recannulate or alter tubing. Thirty-five children underwent veno-arterial modified ultrafiltration; the results show significant increases in postoperative hematocrit, early extubation, and improved rheology.

Cardiopulmonary Bypass↗
PubMed1997

Nineteen-millimeter aortic St. Jude Medical heart valve prosthesis: up to sixteen years' follow-up.

UNLABELLED: BACKGROUND; Prosthetic valve replacement in a small aortic root without annulus enlargement raises concern about its long-term benefits. METHODS: Between July 1979 and June 1994, 104 (18%) of 593 patients underwent aortic valve replacement using the 19-mm St. Jude Medical heart valve prosthesis. There were 93 women and 11 men, with a mean age of 66.2 +/- 10.6 years. Forty-four patients (42%) were 70 or more years old. The mean body surface area was 1.61 +/- 0.16 m2 (range, 1.2 to 2.1 m2). Forty-nine patients (47%) underwent concomitant procedures; 23 patients (22%) required coronary artery bypass grafts and 25 patients (24%), mitral valve replacement. Ninety-eight patients (94%) presented in New York Heart Association class III and IV. RESULTS: The operative mortality was 7.6% (8 patients). Follow-up was 100% with a mean of 5.48 +/- 3.73 years (range, 1 to 16 years) and a total of 708 patient-years. There were 18 late deaths, with a mortality of 2.5% patient-years. The incidence of thromboembolism was 0.4% patient-years (3 patients) and anticoagulant-related morbidity was 0.85% patient-years (6 patients). Long-term survival in the two groups with a body surface area of less than 1.7 m2 and 1.7 m2 or more was not statistically different (p = 0.30). The univariate analysis with body surface area as a predictor of mortality showed that a larger body surface area had no effect on the long-term mortality (chi2 p value = 0.36). Survival for 5 and 10 years with the 95% confidence interval was 80.6% +/- 8.3% and 61.6% +/- 15%. Freedom from thromboembolism was 96.3% +/- 4.2% and anticoagulant-related hemorrhage was 91.8% +/- 6.8% at the end of 16 years. Cox proportional hazards model, with time-dependent covariates, showed that events of thromboembolism, anticoagulant-related hemorrhage, and myocardial infarction during follow-up increased the risk of late death (risk ratio, 9.5, 10.3, and 32.8, respectively). The age at operation was an independent risk factor, with decreased survival with age 70 or more years (p = 0.0002). However, body surface area (p = 0.97) and concomitant cardiac procedures (p = 0.86) were not statistically significant predictors of death. CONCLUSIONS: The long-term performance of the 19-mm St. Jude Medical heart valve prosthesis in the small aortic root is satisfactory irrespective of the body surface area, and it is a viable alternative for such patients.

Adult↗
PubMed1997

St. Jude Medical cardiac valves in small aortic roots: follow-up to sixteen years.

Prosthetic aortic valve replacement in the small aortic root raises concerns of its long-term effects. Between 1978 and 1994, 270 patients received only small aortic prostheses (< or = 21 mm). There were 117 men (43.3%) and 153 women (56.7%) with a mean age of 64.3 +/- 11.6 years (range 19 to 87 years). The body surface areas ranged from 1.2 to 2.26 m2 (mean 1.71 +/- 0.27 m2). Ninety-one percent of patients had New York Heart Association class III or IV symptoms and 33% underwent concomitant coronary artery bypass grafting. The operative mortality rate was 3.3% (9 deaths) and follow-up (100%) extended from 1 to 16 years (mean 6.2 +/- 3.9 years) with cumulative survival of 1676 patient-years. There were 55 late deaths (3.28% per patient-year). The linearized rates of morbidity reported as percent per patient-year were as follows: structural failure, 0%; paravalvular leak, 0.12%; prosthetic endocarditis, 0.24%; anticoagulant-related morbidity, 1.24%; and thromboembolism, 1.10%. In 89% of the survivors New York Heart Association functional performance had improved to class II or I. The actuarial survival with 95% confidence intervals at 5, 10, and 16 years was 86.9% (82.5%, 91.3%), 68.6% (60.6%, 76.6%), and 53.6% (36.6%, 70.6%), respectively. Freedom from late valve-related events (95% confidence intervals) at 10 and 16 years was as follows: thromboembolism, 91.2% (86.6%, 95.8%) and 78.3% (62.6%, 94%); anticoagulant-related morbidity, 89.1% (83.8%, 94.4%) and 81.0% (65.1%, 96.9%); and prosthetic endocarditis, 98.8% (97.5%, 100%) and 98.8% (97.5%, 100%), respectively. Multivariate analysis revealed age at operation, myocardial infarction, and endocarditis affected the long-term survival. The risk of sudden death irrespective of body surface area and valve size was not statistically different. Thus the long-term performance of the St. Jude Medical valve in small aortic roots is satisfactory.

Adult↗
PubMed1995

Stroke during coronary artery bypass grafting using hypothermic versus normothermic perfusion.

Does the abandonment of hypothermic perfusion during cardiopulmonary bypass compromise cerebral protection and thus lead to a higher incidence of stroke? From 1987 to June 1993, 2,585 consecutive patients underwent myocardial revascularization using warm-body (perfusion at 37 degrees C), cold-heart (cold cardioplegic arrest) surgical technique and were followed for new overt neurologic deficits. Perfusion pressure was maintained between 50 and 70 mm Hg, and hematocrit was kept around 20%. There were 25 operative deaths (1%) in this normothermic group, and new neurologic deficits developed after operation in 25 patients (1%). These results were compared retrospectively with those in 1,605 patients who underwent myocardial revascularization between 1980 and 1986 with moderate hypothermic (25 degrees to 30 degrees C) perfusion, the same surgical team, and similar operative techniques. The normothermic group included more elderly patients, more patients with left ventricular dysfunction and unstable angina, and more frequent use of an internal mammary artery conduit. Neurologic complication rates were 1% and 1.3% for the normothermic and hypothermic perfusion groups, respectively. Risk factors for stroke that were identified included age greater than 70 years, severity of aortic arch atherosclerosis, and severe hypotension in the perioperative period. Thus, in a large clinical series, the incidence of overt neurologic injuries was found to be no higher with normothermic perfusion than with hypothermic perfusion.

Aged↗
PubMed1994

Neurological complications during myocardial revascularization using warm-body, cold-heart surgery.

Does the use of warm-body perfusion in elderly patients with severe cerebrovascular disease lead to a higher incidence of stroke, due to hypotension secondary to low systemic vascular resistance? Two thousand, three hundred eighty-three (2,383) consecutive myocardial revascularizations were performed (1987-1992) using warm-body (perfusion 37 degrees C), cold-heart surgery (cold cardioplegic arrest). The perfusion pressure was maintained between 50-70 torr; hematocrit was kept around 20%. Prospective data during hospitalization revealed 23 operative deaths (1%), and 24 patients (1%) who developed new neurological signs after surgery. The latter formed three groups: Group I consisted of six patients with severe neurological deficits, who never regained consciousness and died after support systems withdrawal. Group II included 14 patients with postoperative clinical evidence of focal cerebral infarction (9 had hemiplegia, 2 had visual disturbance, and 3 showed alteration of memory), all of whom had residual defects at discharge; Group III was composed of four patients with minor neurological deficits after surgery (hemiparesis, gait disturbance, mental changes) which had cleared up by discharge. These data were compared retrospectively with 1605 patients (1980-1986) undergoing myocardial revascularization with moderate (25-30 degrees C) hypothermia and the same surgical team and operative techniques. Both groups had similar preoperative demographics except the warm group included more elderly patients, higher numbers with unstable angina and poor ejection fraction, and more frequent use of a mammary artery conduit. Neurological complications were 1% and 1.3% for the normothermic and hypothermic perfusion groups respectively. Incremental risk factors of stroke remain: age over 70 years, diffuse atherosclerosis of the aorta, carotid occlusive disease, and severe hypotension during perfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Perioperative paraplegia and multiorgan failure from heparin-induced thrombocytopenia.

Heparin-induced thrombocytopenia and thrombosis syndrome is a rare but devastating complication. We report a patient with heparin-induced thrombocytopenia in whom heparin-induced thrombocytopenia and thrombosis syndrome developed after a cardiac operation, complicated by acute thrombosis of the aorta followed by renal failure, paralysis, and ischemic necrosis of the lower extremities. The literature suggests aspirin, dipyridamole, and iloprost as effective prophylactic agents for perioperative heparin-induced thrombocytopenia and thrombosis syndrome. This unfortunate complication underscores the importance of close platelet count monitoring in all preoperative patients undergoing prolonged heparin therapy.

Aorta, Abdominal↗
PubMed1993

Warm body, cold heart surgery. Clinical experience in 2817 patients.

Systemic hypothermia is used almost universally in cardiac surgery. Since 1987, 2817 patients have had normothermic cardiopulmonary bypass (NCPB, "warm body", bladder temperature 36 degrees C) with cold blood cardioplegic arrest ("cold heart", 8 degrees-14 degrees C) during open heart surgery. No patients were denied this technique regardless of age, condition or severity of surgery. Clinical Characteristics in Patients: Age range: 16-84 years, mean 66; male/female ratio 3:1; pump time (min) 24-183, mean 91; cross-clamp time (min) 15-148, mean 68; types of surgery: coronary artery bypass (n = 2214), valvular (n = 489) and miscellaneous (aneurysms, tumors, arrhythmias, congenital, etc) (n = 114). One thousand and sixty-nine (1069) patients had urgent coronary artery bypass grafting (CABG). The ejection fraction was less than 0.40 in 843 patients (30%). The thirty-day operative mortality for the entire group was 1.7% (48/2817 patients): CABG = 1% (23/2214 patients), valvular = 3% (15/489 patients) and miscellaneous 9% (10/114 patients). Postoperative complications were: perioperative myocardial infarction (34 patients) = 1.2%, postoperative bleeding requiring reexploration (37 patients) = 1.3%, stroke (27 patients) = 1%, and mediastinal infection (21 patients) = 0.7%. During NCPB (WARM) systemic vascular resistance was extremely low, cardiac output was high and it was easier to wean patients from the pump. No intraaortic balloon pump was used during this period. Pulmonary complications and coagulopathy were extremely rare. These results provide reassurance that NCPB (WARM) in combination with cold cardioplegic arrest provides excellent myocardial and total body protection during cardiac surgery and is particularly suitable for high-risk patients.

Aged↗
PubMed1993

Right ventricular function after normothermic versus hypothermic cardiopulmonary bypass.

Normothermic systemic perfusion in patients undergoing cardiopulmonary bypass may compromise myocardial hypothermia, a mainstay for preservation of ventricular function during iatrogenic cardiac arrest. The right ventricle is the area of the heart most susceptible to rewarming. We prospectively evaluated myocardial rewarming and indexes of right ventricular function in 30 patients undergoing coronary artery bypass grafting randomized to receive moderate hypothermic (bladder temperature 25 degrees C) or normothermic perfusion and multidose cold blood cardioplegia during cardiopulmonary bypass. All patients had significant stenosis (> 70%) of the right coronary artery, and in 27 of 30 the right coronary artery was revascularized. A right ventricular ejection fraction/volumetric catheter was used to assess right ventricular function by right ventricular ejection fraction and a preload (right ventricular end-diastolic volume) normalized right ventricular stoke work index in the prebypass and postbypass periods. Findings included the following: (1) Greater rewarming of all areas of the heart occurs with normothermic bypass, with the mean temperature difference at the end of each intracardioplegic period ranging from 4.0 degrees to 6.3 degrees C warmer than with hypothermic bypass; (2) the right ventricle was not more susceptible to rewarming than the posterior left ventricle or interventricular septum in either group; (3) right ventricular function did not differ between groups at any time in the study, including the immediate postarrest period; and (4) right ventricular function was preserved and equivalent to the prebypass baseline. We conclude that the moderate myocardial rewarming that occurs with normothermic perfusion does not compromise right ventricular preservation in patients with right coronary artery disease undergoing revascularization with multidose cold blood cardioplegia to maintain electromechanical arrest.

Aged↗
PubMed1993

Warm body, cold heart: myocardial revascularization in 2383 consecutive patients.

Systemic hypothermia is used almost universally in cardiac surgery. Since 1987, 2383 patients underwent normothermic cardiopulmonary bypass (NCPB, "warm body", bladder temperature 36 degrees C) with cold blood cardioplegic arrest ("cold heart", 8-14 degrees C) during myocardial revascularization. No patients were denied this technique regardless of age, condition or severity of surgery. Clinical characteristics in patients: Age range: 31-92 years, mean 66; male/female ratio 3:1; pump time (min): 23-228, mean 80; cross clamp time (min): 18-152, mean 60. One thousand, one hundred and sixty-one patients (49%) had urgent coronary artery bypass grafting (CABG). Ejection fraction was less than 0.4 in 843 patients (30%). Thirty-day operative mortality was 1% (23/2383 patients). Postoperative complications were: perioperative myocardial infarction (35 patients) = 1.5%; postoperative bleeding requiring reexploration (33 patients) = 1.4%; stroke (22 patients) = 0.9%; mediastinal infection (24 patients) = 1%; and renal insufficiency (25 patients) = 1%. During NCPB (warm), systemic vascular resistance was extremely low, cardiac output was high and it was easier to wean patients from the pump. No patient required the intraaortic balloon pump during peri- and post-operative periods. Pulmonary complications and coagulopathy were extremely rare. These results provide reassurance that NCPB (warm) in combination with cold cardioplegic arrest provides excellent myocardial and total body protection during myocardial revascularization and is particularly suitable for high-risk patients.

Aged↗
PubMed1992

Aortic valve replacement (AVR): influence of age on operative morbidity and mortality.

Retrospective analysis of 306 patients following aortic valve replacement (AVR) was carried out between 1985-89. Patients were divided into two groups: group 1 patients were less than 70 years of age and group 2 were greater than 70 years of age. The multivariant analysis of risk factors showed the only increased risk for surgery was the NYHA class IV in either group. There was no overall difference in morbidity and mortality. The actuarial survival rate for group 2 patients was 95% at 1 year and 75% at 5 years. This was not different when compared for death in age- and sex-matched controls from the general population. AVR in the elderly is safe, the long-term result is good and it remains the treatment of choice unless there is an absolute contraindication.

Age Factors↗