Minimal operative mortality in patients undergoing coronary artery bypass with significant left ventricular dysfunction by maximization of metabolic and mechanical support

Abstract

Between January 1, 1992, and January 23, 1996, 111 consecutive patients with severe left ventricular dysfunction underwent isolated coronary artery bypass grafting. The ejection fraction in these patients ranged from 10% to 34% (mean 27.9% +/- 5.4%); in 18 patients the value was less than 20%. The high operative mortality rate (7.6% in Society of Thoracic Surgeons database) in this group of patients at high risk was targeted for reduction by provision of, in addition to the usual inotropic support, progressively more intensive metabolic and mechanical support. The metabolic support consisted of triiodothyronine; glucose, insulin, and potassium; aspartate/glutamate in the cardioplegic solution; and warm-cold-warm/antegrade-retrograde-antegrade cardioplegia. Mechanical support included liberal use of the intraaortic balloon pump, use of a new occlusive retrograde cardioplegia catheter, ultrafiltration to remove myocardial depressant factors, and, finally, delayed sternal closure. The operative mortality rate was 1.8% (2/111). Complications included reoperation because of bleeding (3.6%, 4/111), mediastinitis (1.8%, 2/111), and stroke (0.9%, 1/111) and there were no occurrences of new postoperative acute renal failure (0.0%, 0/111). The intensive care unit stay was 2.2 +/- 0.9 days with a length of stay in the hospital of 13.7 +/- 22.1 days. These techniques done before operation, intraoperatively, and postoperatively optimize the milieu of the depressed left ventricle by maximizing perioperative high-energy phosphate bonds; increasing the effectiveness of inotropic agents; unloading the left ventricle by chemical, metabolic, and mechanical support; and removing known myocardial depressant factors, which reduced the operative mortality rate to 1.8% compared with 7.6% as reported in the Society of Thoracic Surgeons' database.

A metabolic protective strategy could improve long-term survival in patients with LV-dysfunction undergoing CABG

“…Poor or even average results are less likely to be published. Typically the published papers differ from the STS data base from the corresponding time reporting a substantially higher mortality of 7.6% in patients with EF≤0.35 (48). Furthermore, the majority of studies are highly selected case series excluding patients that required valve procedures, redo-procedures, patients with cardiogenic shock and occasionally only including those that hade viable myocardium detected preoperatively or even excluding those that required IABP, had recent preoperative events or died early after surgery.…”

Vascular and renal function in experimental thyroid disorders

“…Administration of T 3 has been proposed to increase cardiac output and to decrease vascular resistance in certain clinical settings when conventional inotrophic drugs prove insufficient (190). Patients with poor ventricular function may benefit the most from the use of T 3 through a reduction in the need for conventional inotrophic drugs (191). Additionally, in the rat postinfarction model of heart failure, treatment with T 4 produced a positive inotrophic response, including an increase in left ventricular conractility and an increase in left ventricular end-diastolic pressure (192).…”

Oral triiodothyronine for the prevention of thyroid hormone reduction in adult valvular cardiac surgery

“…The longer aortic clamping time and lower ejection fraction in the T group, although not statistically significant (P = 0.083 and 0.099, respectively), raise the possibility that the patients randomly allocated to this group had more complex cardiopathies and that their surgical procedure was more complicated. Other studies demonstrated that T 3 replacement reduced clinical endpoints postoperatively, such as the need for pacemaker and mechanical assistance, use of vasoactive drugs, need for intensive care, or prevalence of atrial fibrillation (8,10,12,15,18), and some studies have even suggested decreased mortality (13,14).…”

“…Several studies have explored the intravenous administration of T 3 to adults (8)(9)(10)(11)(12)(13)(14) and, more recently, to children (15)(16)(17), during the cardiac surgery postoperative period. The results concerning clinical benefits, actual hemodynamic effects and need for inotropic drugs have been controversial.…”