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Biomedical subjects

M D Strong

Publications and source records attributed to M D Strong.

9 recordsLinked to original sources
PubMed1991

Hemostatic effects of tranexamic acid and desmopressin during cardiac surgery.

BACKGROUND: Desmopressin-induced release of tissue plasminogen activator from endothelial cells may explain the absence of its hemostatic effect in patients undergoing cardiac surgery. Prior administration of the antifibrinolytic drug tranexamic acid might unmask such an effect, and combination therapy might thereby improve postoperative hemostasis. METHODS AND RESULTS: A double-blinded design randomly allocated 163 adult patients undergoing coronary revascularization, valve replacement, both procedures, or repair of atrial septal defect to four treatment groups: placebo, tranexamic acid given as 10 mg/kg over 30 minutes followed by 1 mg.kg-1.hr-1 for 12 hours initiated before skin incision, desmopressin given as 0.3 micrograms/kg over 20 minutes after protamine infusion, and both drugs. One surgeon performed all operations. Blood loss consisted of mediastinal tube drainage over 12 hours. Follow-up visits sought evidence of myocardial infarction and stroke. Desmopressin decreased neither the 12-hour blood loss nor the amount of homologous red cells transfused. Tranexamic acid alone significantly reduced 12-hour blood loss, by 30% (mean, 318 versus 453 ml; p less than 0.0001), without enhancement by desmopressin. Tranexamic acid also decreased the proportion of patients receiving homologous blood within 12 hours of operation (8% versus 21%, p = 0.024) and within 5 days of operation (22% versus 41%, p = 0.011). CONCLUSIONS: Desmopressin exerts no hemostatic effect, with or without prior administration of antifibrinolytic drug. Prophylactic tranexamic acid alone appears economical and safe in decreasing blood loss and transfusion requirement after cardiac surgery.

Blood Coagulation Tests↗
PubMed1990

Prophylactic tranexamic acid decreases bleeding after cardiac operations.

Thirty-eight patients undergoing a cardiac operation randomly received either tranexamic acid, a potent inhibitor of plasminogen, or placebo in an effort to determine whether prophylactic antifibrinolytic therapy reduces chest tube drainage. Twelve-hour blood loss was 750 +/- 314 (standard deviation) ml in the placebo group and 496 +/- 228 ml in the drug group (p = 0.0057). Fibrin split products were present more frequently in patients in the placebo group (17 of 20 compared with four of 18 in the drug group; p = 0.0002). Tranexamic acid markedly decreased plasminogen availability (112 +/- 104 units in the placebo group versus 36 +/- 18 units in the drug group, p = 0.0058). Plasma fibrinogen concentrations were similar in the placebo and drug groups. Patients in the placebo group received more fresh-frozen plasma and more mediastinal shed blood than those in the drug group. No coagulation-related complication occurred in the group receiving tranexamic acid. We conclude that prophylactic tranexamic acid can be administered safely to inhibit fibrinolysis during cardiac operations, decrease postoperative bleeding, and possibly decrease the frequency of blood product transfusion.

Adult↗
PubMed1987

Exercise radionuclide assessment of left ventricular function before and after coronary bypass surgery.

The effects of elective saphenous vein coronary artery bypass surgery on left ventricular ejection fraction were assessed by using exercise first-pass radionuclide angiography in 66 consecutive patients. All patients with left main coronary artery or concomitant valvular disease were eliminated from the study. Before surgery, 7 patients had normal postexercise left ventricular function (Group 1), 33 had normal resting left ventricular function with an abnormal response to exercise (Group 2), and 26 had an abnormal resting left ventricular ejection fraction with an abnormal response to exercise (Group 3). Following surgery, patients in all three groups had no change in mean resting left ventricular ejection fraction; however, patients in Groups 2 and 3 had significant improvement in mean postexercise left ventricular ejection fraction (p less than 0.0001 and p less than 0.0054 respectively), whereas patients in Group 1 did not. Previous studies reported improvement in postexercise ejection fraction in patients with reduced resting left ventricular function and with an ischemic response to exercise (Group 3). But this is the first study to confirm improvement in postexercise function in patients with normal resting function and an ischemic response to exercise (Group 2).

Adult↗
PubMed1985

Left ventricular function after elective aneurysmectomy.

Employing rest and exercise first-pass radionuclide angiography before and 3 months after surgery, we studied patients with hemodynamically stable left ventricular aneurysm (LVA) undergoing both coronary artery bypass surgery to relieve angina pectoris and elective aneurysmectomy. There were 15 patients, 14 men and 1 woman with a mean age of 54 +/- 7 years. All patients had anterior and/or apical LVA. After surgery the postexercise mean left ventricular ejection fraction (LVEF) for the whole group improved significantly (p less than 0.004) compared with the preoperative value, but the resting LVEF did not change. The duration of exercise improved (p less than 0.01) after surgery, but not the double product. However, based upon the preoperative LVEF response to exercise, two groups were seen: Group A (n = 5) had greater than or equal to 5% increase in their LVEF with exercise versus Group B (n = 10), who had less than 5% increase or a decrease in their LVEF. Postoperatively, Group A decreased their LVEF with exercise and failed to improve exercise capacity or double product. Postoperatively, Group B increased the LVEF by greater than or equal to 5% as well as increasing exercise capacity (p less than 0.01), and double product (p less than 0.03). Group A had lower preoperative LVEF than Group B (p less than 0.01) and larger LVA. Patients with hemodynamically stable LVA who require coronary artery bypass surgery for angina should not have aneurysmectomy. The presence of hemodynamically stable LVA is not a contraindication to deriving benefit from myocardial revascularization.

Adult↗
PubMed1985

Rigid intraluminal prosthesis for replacement of thoracic and abdominal aorta.

During the past seven years, 80 patients have undergone aortic substitution using a rigid intraluminal prosthesis. There were 9 early deaths. The procedures involved 32 dissecting aneurysms (18 ascending and 14 descending), 16 atherosclerotic aneurysms of the ascending aorta and 13 atherosclerotic aneurysms of the descending aorta, 3 thoracoabdominal aneurysms, 2 arch aneurysms, and 14 abdominal aortic aneurysms. There was one early dislodgment of the rings necessitating reoperation, but no other early complications related to the procedure. In the follow-up period (mean, 25 months) there were 6 late deaths. One occurred 6 months after operation in a patient with empyema. There were no late complications of thrombosis, erosion, pseudoaneurysm formation, or hemorrhage. The follow-up data are extremely encouraging. We now are using this device whenever possible in all substitutions of the aorta, although in approximately 40% of patients, it is necessary to remove one of the spools and suture either the proximal or distal end of the graft owing to the close proximity of the aneurysm to the coronary ostia or the origin of the subclavian artery. Important techniques of insertion and postoperative angiograms are presented.

Adolescent↗
PubMed1985

Cryothermal mapping of recurrent ventricular tachycardia in man.

Intraoperative reversible cryothermal mapping of recurrent ventricular tachycardia was performed in seven patients with left ventricular aneurysms with use of a 0 degrees C ice probe. A single, reproducible cryotermination site was found in each patient. The cryotermination site was uniformly located in an area where local electrograms obtained during ventricular tachycardia showed electrical activation during the diastolic portion of the surface electrocardiogram, and was different than the site of activation coincident with the onset of the QRS complex on the surface electrocardiogram (earliest reactivation site or ERS) by 4.5 +/- 2.7 cm (mean +/- SD) in five of seven patients. Sinus rhythm late potentials were recorded at the cryotermination site in five of six patients and from the ERS in one. In five patients, extensive subendocardial resection including both the ERS and cryotermination sites was performed. In two patients only the cryotermination site was excised. In six survivors, including one in whom only the cryotermination site was excised, ventricular tachycardia could not be induced 2 weeks after surgery and has not recurred during the follow-up period of 7 to 17 months (12 +/- 4.5 months, mean +/- SD). Reversible cryothermal mapping may provide additional important information not obtained by standard electrogram mapping of ventricular tachycardia that may help guide surgical therapy of recurrent ventricular tachycardia.

Cold Temperature↗
PubMed1977

Successful correction of all mechanical complications of ischemic heart disease in the same patient.

Extensive surgery for all of the mechanical complications of ischemic heart disease is feasible with early diagnosis, catheterization, and aggressive medical and surgical therapy. A patient is report who, after recovering from cardiogenic shock, required a coronary bypass, closure of ventricular septal defects, mitral valve replacement, aneurysmectomy, and temporary pacemaker wires. The outcome was successful.

Aged↗
PubMedDate not supplied

Repair of caval lacerations during cardiac surgery.

Inadvertent tears to the atrial caval junction during open heart surgery can present as a disastrous complication. A method is described by which a flap of pericardium is mobilized and sutured over the caval laceration. Control of bleeding is facilitated and caval obstruction is minimized.

Cardiac Surgical Procedures↗