Coronary artery bypass surgery in patients with severely impaired left ventricular function]

The efficacy and problem of coronary artery bypass grafting (CABG) in patients with severely impaired left ventricular function (left ventricular ejection fraction < or = 30%) were assessed in 27 patients of whom 17 (group 1) underwent emergent CABG and 10 (group 2) elective between Jan 1984 to Aug 1990. As a whole, history of myocardial infarction (24/27, 88.9%), large left ventricular volume with reduced ejection fraction (LVEDVI 126.08 +/- 25.91 ml/m2, LVESVI 93.04 +/- 21.02 ml/m2, LVEF 25.04 +/- 4.75%) and multiple vessel disease with at least one vessel total occlusion (20/27, 74.1%) were characteristically seen in these patients. The patients of group 1 were significantly older (mean 66.12 +/- 5.68 vs 57.10 +/- 8.08, p < 0.01) and needed more frequent preoperative support with IABP (17/17 vs 4/10, p < 0.01). Using Thallium-201 scintigraphy, in 10 patients of group 1 and 9 of group 2, myocardial viability in the proposed bypass area was evaluated before operations. Average 2.37 +/- 0.79 grafts were placed and continuous retrograde cold blood cardioplegia via the coronary sinus was employed for myocardial protection. Two mitral annuloplasty (MAP) for ischemic mitral regurgitation and 2 cryoablation for the treatment of ventricular tachycardia were performed concomitantly. Operative mortality was 47.1% in group 1 and none in group 2 (p < 0.05). Two cases of MAP died, but two cases of cryoablation survived. Postoperative LVEF was improved significantly only in group 2 (p < 0.05), but during the follow-up period of 7 months to 6 years, all 19 survivors expect one remains with NYHA class I or II.(ABSTRACT TRUNCATED AT 250 WORDS)     

Perioperative management of patients with impaired left ventricular function

The development of acute perioperative left ventricular failure leading to haemodynamic catastrophe has several reasons. The management of left ventricular dysfunction requires a step-by-step therapeutic approach. Extensive haemodynamic monitoring is fundamental to distinguish between the need for positive inotropes, lowering pre- or afterload or increasing perfusion pressure by vasopressors. Catecholamines are still the cornerstone for treating acute left ventricular dysfunction. Whether synthetic, costly catecholamines offer any advantage over 'natural', low-priced catecholamines has not yet been definitely determined. Optimizing ventricular loading by vasoactive substances will help to improve overall myocardial performance. Knowledge of pre-existing cardiac disease and of haemodynamic principles are prerequisites for selecting an appropriate therapeutic regime. This appears to be more important for successfully treating acute perioperative myocardial failure than waiting for a new 'magic' substance.     

Nifekalant hydrochloride effective against perioperative ventricular tachycardia in patients with impaired left ventricular function

Perioperative ventricular tachycardia (VT) was treated with nifekalant hydrochloride, a pure potassium channel blocker in 2 patients with low left ventricular ejection fraction (LVEF). The first patient is a 34-year-old woman, a chronic hemodialysis patient in whom severe aortic stenosis due to structural valvular deterioration of the previously implanted tissue valve was diagnosed with her LVEF of 26.9%. She underwent urgent redo aortic valve replacement with a mechanical valve. Postoperatively a sustained VT developed. After she received direct-current (DC) shock, nifekalant hydrochloride was administered. The 2nd patient is a 44-year-old man who presented with severe congestive heart failure. A coronary angiogram revealed triple vessel disease as well as decreased LVEF of 16% and ischemic mitral regurgitation. He underwent triple coronary artery bypass grafting and mitral ring annuloplasty. A VT developed requiring DC shock during hemostasis. Nifekalant hydrochloride was given immediately. In both patients, nifekalant hydrochloride was given intravenously in a dose of 0.3 mg/kg followed by a continuous intravenous infusion at a dose of 0.4 mg/kg/hr. Our experience shows nifekalant hydrochloride is effective against perioperative VT, especially in patients with impaired left ventricular function since it has mild positive inotropic effect.     

Levosimendan for patients with impaired left ventricular function undergoing cardiac surgery

The efficacy of levosimendan treatment for a low cardiac output status following cardiac surgery has not been established. Here, we review our initial experiences of the perioperative use of levosimendan. This study is a retrospective uncontrolled trial. Nine patients who underwent cardiac surgery, and developed a low cardiac output status resistant to conventional inotropic support, were given levosimendan. The mean preoperative ejection fraction was 35.2+/-3.4%. All patients were on concomitant inotropic agents and had previously undergone intra-aortic balloon pumping. Cardiac index increased immediately from 2.14+/-0.33 l/min/m(2) at baseline to 2.41+/-0.31 (P=0.02) at 1 h, rising to 2.67+/-0.43 (P<0.001) at 4 h after the loading dose was started. Similarly, the systemic vascular resistance index decreased from 2350+/-525 dynes/s/cm(-5)/m(2) at baseline to 1774+/-360 (P=0.002) at 4 h. In the case of all but one of the patients, either the dose of the concomitant inotropic support or the balloon pumping could be weaned down within 24 h after completion of the levosimendan infusion. No withdrawal of levosimendan was required. Levosimendan could constitute a new therapeutic option for postoperative low cardiac output.     

Surgery of secondary mitral insufficiency in patients with impaired left ventricular function

Background  

Secondary mitral insufficiency (SMI) is an indicator of a poor prognosis in patients with ischemic and dilated cardiomyopathies. Numerous studies corroborated that mitral valve (MV) surgery improves survival and may be an alternative to heart transplantation in this group of patients.     

Effects of fentanyl on left ventricular diastolic function

Effects of fentanyl on left ventricular diastolic function were investigated in chronically instrumented dogs. An electromagnetic mitral flow probe was placed in the left atrium and a micromanometer was placed in the left atrium as well as in the left ventricle to measure ventricular pressure (LVP), left atrial pressure (LAP), derivative of left ventricular pressure (dp/dt), mitral flow (MIF) and ECG in conscious resting dogs. Following induction of anesthesia with thiopental (15-20 mg.kg-1) and vecuronium (0.1 mg.kg-1), fentanyl (10, 50 and 100 mcg.kg-1) was administered at 30 min intervals. The direct measurement of phasic MIF was used to obtain a set of diastolic indices: peak rapid filling period (PRFR), filling volume (FV), FV due to atrial contraction (FV-A), isovolumic relaxation period (IVRP) and diastolic filling period (DFP). Each diastolic index during conscious resting state was compared with that obtained during fentanyl anesthesia using paired t-test. There were no significant changes in those diastolic indices under fentanyl (10, 50 and 100 mcg.kg-1) anesthesia except PRFR and dp/dt under fentanyl 10 mcg.kg-1 which decreased. Although heart rate decreased about 50% under fentanyl, IVRP and PRFR did not increase significantly, but DFP (P less than 0.05) and FV (P less than 0.01) increased significantly. DFP correlated well with RR interval under conscious resting state under fentanyl anesthesia (r = 0.992 and r = 0.967). This study suggests that in the absence of surgical stress, fentanyl does not impair left ventricular diastolic function.     

Use of an intraaortic balloon pump in patients with impaired left ventricular function.

Prophylactic use of an intraaortic balloon pump (IABP) prior to open-heart surgery in patients with impaired left ventricular function is still under debate. Patients with left ventricular ejection fraction (LVEF) < 40% were therefore compared according to time of IABP placement, viz. preoperative (n = 56), intraoperative (n = 40) or postoperative (n = 17), and also with patients who did not receive mechanical support despite LVEF < 40% (n = 78). The main indication for preoperative IABP insertion was severely impaired left ventricular function (80%), while patients with intraoperative or postoperative IABP placement mainly presented with low cardiac-output syndrome (70%/53%). Preoperative IABP was associated with a low mortality rate (8.9%), whereas patients with intraoperative or postoperative IABP placement had a high mortality risk and an increased catecholamine requirement. Of the patients scheduled for surgery without prophylactic IABP, 19% required intra- or postoperative insertion. Prophylactic placement of IABP thus reduced the mortality rate as well as the postoperative need for mechanical and catecholamine support. Need for intraoperative IABP insertion was associated with high mortality, whereas the outcome after postoperative IABP placement depended on the indication for the measure.     

Aortic valve replacement in patients with impaired ventricular function

BACKGROUND: Patients with reduced ventricular function undergoing aortic valve replacement have increased operative risks, but the impact of valvular pathophysiology and other risk factors has not been clearly defined. METHODS: From June 1992 through June 2002, 1,402 consecutive patients underwent isolated aortic valve surgery with or without coronary artery bypass grafting; of these patients, 416 had an ejection fraction less than 40% and are the subject of this report. These patients (mean age, 68.6) had severe stenosis (62.5%), severe regurgitation (30.3%), or mixed disease (7.2%). Aortic valve replacement plus coronary artery bypass grafting was performed in 48.4% of patients, and 27% had previous cardiac surgery. Follow-up included echocardiography and survival analysis. RESULTS: Hospital mortality was 10.1% (42 of 416), with no difference between aortic stenosis (9.6%) and regurgitation (11.1%). Multivariate analysis revealed that age (p = 0.002) and renal disease (odds ratio = 4.2; 95% confidence interval, 1.9 to 9.3; p = 0.001) were independently associated predictors of mortality. Valvular pathophysiology had no impact on mortality. Peripheral vascular disease, multivessel coronary disease, and renal disease were associated risks for any postoperative complication. Peripheral vascular disease (odds ratio = 12.3, p = 0.02), history of cerebrovascular disease (odds ratio = 4.8, p = 0.038), and diabetes (odds ratio = 2.7, p = 0.04) were associated risks for stroke. The ejection fraction was more than 40% in 52% of the patients who had postoperative echocardiography (mean follow-up, 6 months). Actuarial survival revealed no difference between pathophysiologic groups. CONCLUSIONS: Aortic valve surgery in patients with impaired ventricular function carries an acceptable operative risk that can be stratified by age and comorbidities. The type of valvular pathophysiology does not significantly affect mortality.     

Coronary artery bypass surgery in patients with impaired left ventricular function. Predictors of hospital outcome

This prospective study evaluates the surgical outcome of 75 consecutive patients with impaired left ventricular function, including an analysis of predictors of the short-term outcome following coronary artery bypass grafting (CABG). Seventy-five patients (mean age 64 +/- 13 years) with coronary artery disease and impaired left ventricular function (left ventricular ejection fraction [EF] < or = 40%) who underwent a coronary artery bypass surgery were prospectively studied. Echocardiography and thallium-201 myocardial scintigraphy were preoperatively performed to measure the left ventricular function and to assess myocardial viability. Postoperative echocardiography was done before discharge and six months later to evaluate recovery of left ventricular function. Five patients (6.7%) died in total: three deaths were cardiac related (4%) and two patients (2.7%) died due to other causes. The left ventricular ejection fraction improved immediately after the operation (from 32.2 +/- 6% to 39.5 +/- 8%, p = 0.01) and showed a sustained improvement at later follow-up (mean = 16.3 +/- 4.5 months) (44.0 +/- 4.0%, p = 0.01). The left ventricular wall motion score improved significantly only at later follow-up (from 12.2 +/- 1.8 to 9.4 +/- 2.0, p = 0.03). In 43 patients of whom a preoperative thallium-201 scintigraphy was available, the presence of extensive reversible defects was correlated with significant improvement in EF. On the other hand, a poor outcome was correlated with the presence of pathological Q waves in the preoperative ECG and with an increased left ventricular end-systolic volume index (> 100 ml/m2). Patients with marked left ventricular dysfunction can safely undergo CABG with a low mortality and morbidity. The presence of extensive reversible defects on preoperative thallium-201 scintigraphy is a strong predictor of postoperative recovery of myocardial function. A poor outcome of surgery can be expected in the presence of pathological Q waves on the preoperative ECG or when the left ventricular endsystolic volume index exceeds 100 ml/m2.     

Beating heart ischemic mitral valve repair and coronary revascularization in patients with impaired left ventricular function

OBJECTIVE: The aim of this study is to evaluate in a cohort of patients with impaired left ventricular (LV) function and ischemic mitral valve regurgitation (MVR), the effects of on-pump/beating heart versus conventional surgery in terms of postoperative mortality and morbidity and LV function improvement. MATERIALS AND METHODS: Between January 1993 and February 2001, 91 patients with LVEF between 17% and 35% and chronic ischemic MVR (grade III-IV), underwent MV repair in concomitance with coronary artery bypass grafting (CABG) Sixty-one patients (Group I) underwent cardiac surgery with cardioplegic arrest, and 30 patients (Group II) underwent beating heart combined surgery. Aortic valve insufficiency was considered a contraindication for the on-pump/beating heart procedure. Mean age in Group I was 64.4 +/- 7 years and in Group II, 65 +/- 6 years (p = 0.69). RESULTS: The in-hospital mortality in Group I was 8 (13%) patients versus 2 (7%) patients in Group II (p > 0.1). The cardiopulmonary bypass (CPB) time was significantly higher in Group I (p < 0.001). In Groups I and II, respectively (p > 0.1), 2.5 +/- 1 and 2.7 +/- 0.8 grafts per patient were employed. Perioperative complications were identified in 37 (60.7%) patients in Group I versus 10 (33%) patients in Group II (p = 0.025). Prolonged inotropic support of greater than 24 hours was needed in 48 (78.7%) patients (Group I) versus 15 (50%) patients (Group II) (p = 0.008). Postoperative IABP and low cardiac output incidence were significantly higher in Group I, p = 0.03 and p = 0.027, respectively. Postoperative bleeding greater than 1000 mL was identified in 24 patients (39.4%) in Group I versus 5 (16.7%) in Group II (p = 0.033). Renal dysfunction incidence was 65.6% (40 patients) in Group I versus 36.7% (11 patients) in Group II (p = 0.013). The echocardiographic examination within six postoperative months revealed a significant improvement of MV regurgitation fraction, LV function, and reduced dimensions in both groups. The postoperative RF was significantly lower in Group II patients 12 +/- 6 (%) versus 16 +/- 5.6 (%) in Group I (p = 0.001). The 1, 2, and 3 years actuarial survival including all deaths was 91.3%, 84.2%, and 70% in Group I and 93.3%, 87.1%, and 75% in Group II (p = ns). NYHA FC improved significantly in all patients from both groups. CONCLUSION: We conclude that patients with impaired LV function and ischemic MVR may undergo combined surgery with acceptable mortality and morbidity. The on/pump beating heart MV repair simultaneous to CABG offers an acceptable postoperative outcome in selected patients.     

Myocardial ischaemia in patients with impaired left ventricular function undergoing coronary artery bypass grafting--milrinone versus nifedipin

BACKGROUND AND OBJECTIVE: Myocardial ischaemia and infarction are major complications immediately after coronary artery bypass grafting. They may be due to incomplete surgical revascularization, perioperative anaesthetic management or vasospasm of arterial grafts, e.g. the internal mammary artery. Infusions of nifedipine or milrinone have been advocated to prevent spasm of the mammary artery. The study compared the incidence of myocardial ischaemia after continuous infusion of either nifedipine (0.2 microg kg(-1) min(-1)) or milrinone (0.375 microg kg(-1) min(-1)) in patients with compromised left ventricular function scheduled for elective coronary artery bypass graft. METHODS: After Institutional Review Board approval, this double-blinded randomized clinical study enrolled 30 adult patients with compromised left ventricular function (ejection fraction < 0.4) scheduled for elective coronary artery bypass grafting after written informed consent had been obtained. Ischaemia was detected by Holter electrocardiographic monitoring. The incidence of myocardial cell death was monitored by serial determinations of the creatine kinase-MB (CK-MB) and troponin-I. RESULTS: New ST elevation > or = 0.2 mV or new ST depression < or = 0.1 mV occurred in five of 15 patients in the milrinone group (33.3%) and in 13 of 15 patients (86.6%) in the nifedipine group (P < 0.05). There were increases in CK-MB and troponin-I in both groups. Twenty-four hours postoperatively, CK-MB (P = 0.003) and troponin-I (P = 0.001) were significantly higher in the nifedipine group. CONCLUSIONS: Perioperative continuous infusion of milrinone, compared with nifedipine, results in a significantly lower incidence of myocardial ischaemia and myocardial cell damage after elective coronary artery bypass grafting.     

Outcome of geometric endoventricular repair in impaired left ventricular function

BACKGROUND: Traditionally, repair of left ventricular aneurysms has been limited to patients with large localized ventricular aneurysms. Repair of dyskinetic segments in the setting of poor left ventricular function is still contentious. METHODS: Forty patients underwent geometric endoventricular repair, a new technique of ventricular aneurysm repair, over a 2-year period. Two groups of patients undergoing coronary artery bypass grafting (CABG) for left ventricular dysfunction in the same time period were reviewed. Group 1 comprised 23 consecutive patients who underwent geometric endo-ventricular repair along with CABGs, whereas group II consisted of 22 patients who underwent CABG alone. RESULTS: The early mortality was 9.1% in group I (1 cardiac, 1 noncardiac) and 0 in group II (NS). New York Heart Association class was remarkably improved from 3.4 to 1.4 (p < 0.05) in group I and to a lesser extent in group II (3.7+/-0.5 versus 2.3+/-0.5). Diastolic dimension of left ventricle was significantly reduced from 5.6 cm to 4.4 cm (p < 0.05) in group I and virtually unchanged in group II. There was one late death in each of the groups. CONCLUSIONS: This technique of geometric left ventricular aneurysm repair is useful in patients with dyskinetic segments and may help in reducing cardiac size.     

The effects of remifentanil on hemodynamic response to intubation. A comparative study with fentanyl]

BACKGROUND: The aim of this study was to evaluate the effects of remifentanil in comparison with those of fentanyl on the hemodynamic response to orotracheal intubation. METHODS: Experimental design: prospective comparative and randomized study. Setting: operating room in a neurosurgery department at University. Patients: 50 patients, ASA I or II with age ranging from 32 to 64 years were divided in two groups randomly. Interventions: 25 patients received fentanyl as single bolus dose of 2.0 micrograms/kg and atropine 0.01 mg/kg i.v. as premedication while the remainders received atropine 0.01 mg/kg i.v. and remifentanil 0.2 microgram/kg/min as infusion. All patients were induced with propofol 2.0 mg/kg and cisatracurium 0.15 mg/kg for muscle relaxation and were intubated 4 min after induction of anesthesia. Measurements: Heart rate, SAP, DAP, MAP and RPP were recorded at different times: baseline, induction, intubation, 1, 2, 3 and 4 min after intubation; ECG and pulsoximetry were monitored continuously. Statistical analysis was carried out using ANOVA for repeated measures and Bonferroni t-test a value of p < 0.05 was considered to be significant. RESULTS: Significant increases in PAS were recorded, at intubation and at 1 min after in patients treated with fentanyl; in the remifentanil group significant decreases in SAP at induction and at 4 min after intubation were recorded. HR increased significantly at intubation and at 1, 2 and 3 min after in the fentanyl group. RPP showed a significant decrease at induction in the remifentanil group and significant increases at intubation and at 1, 2 and 3 min after in patients treated with fentanyl. CONCLUSION: In conclusion remifentanil was found to properly control the hemodynamic response to intubation in comparison with fentanyl.     

Implantable cardioverter-defibrillators improve survival after coronary artery bypass grafting in patients with severely impaired left ventricular function

Objective  

Patients with severe left ventricular (LV) dysfunction have a poor long term survival despite complete surgical revascularization. Recent data suggests that the use of Implantable Cardioverter-Defibrillator (ICD) improves survival in patients with severe LV dysfunction. We compared the survival impact of ICD implantation in patients with severe LV dysfunction who underwent CABG.