Surgical myocardial revascularization (CABG) in patients with pulmonary disease: beating heart versus cardiopulmonary bypass.

BACKGROUND: Adverse effects on the respiratory system can be severe in many instances after coronarv artery bypass grafting (CABG) with cardiopulmonary bypass (CPBP). Recently, operative techniques without CPBP have gained widespread consent, thanks to the newly developed retractors that allow satisfactory immobilisation of the surgical field. METHODS: Thirty-seven patients operated upon in our Institution between April 1997 and April 1998 showed an obstructive and/or restrictive pulmonary disease. Twenty-one patients were operated on without CBPB (group A), while 16 patients were operated using CPBP (group B, control). The allocation in each group had been randomised. RESULTS: The length of the operation in group A was less than in group B (196+/-35 minutes vs 235+/-60 minutes), (p=0.014). A significant difference was found in postoperative bleeding: 562+/-381 ml vs 776+/-378 (p=0.046), in postoperative red cell count, hemoglobin level and Hct. Permanence on the ventilator was 19.1+/-13 hours in group B and 13.1+/-6.1 hours in group A (p=0.03). The length of stay in ICU was significantly different: 33.8+/-16.2 hours for group A vs 53.6+/-29.3 hours for group B (p=0.01). No respiratory failure occurred in group A; two patients experienced slow weaning from ventilation assistance and one died from that complication in group B. CONCLUSIONS: Myocardial revascularization without CPBP allows a better postoperative clinical course in patients with advanced pulmonary disease.

Changes in skeletal muscle histology and metabolism in patients undergoing exercise deconditioning: effect of propionyl-L-carnitine.

To define the skeletal muscle abnormalities in patients undergoing exercise deconditioning and evaluate the metabolic effect of propionyl-L-carnitine (PLC), muscle biopsies were obtained from 28 patients with effort angina and 31 control subjects. Coronary artery disease patients received either placebo (n = 12), PLC (1.5 g i.v. followed by infusion of 1 mg/kg/min for 30 min, n = 10), or L-carnitine (1 g i.v. followed by infusion of 0.65 mg/kg/min for 30 min, n = 6) for 2 days. Exercise deconditioned patients treated with placebo showed normal muscle content of total carnitine and glycogen, and decrease in percentage of type 1 fibers (P < 0.01) and in the activity of citrate synthase (P < 0.05), succinate dehydrogenase (P < 0.05), and cytochrome oxidase (P < 0.05), as compared to controls. Both PLC and L-carnitine did not modify muscle fiber composition or enzyme activities, but significantly increased muscle levels of total carnitine by 42% and 31%, respectively (P < 0.05). Moreover, PLC significantly increased glycogen muscle content (P < 0.01), while the equimolar dose of L-carnitine did not. This effect, probably due to the anaplerotic activity of the propionic group of PLC, suggests that this drug may be effective in improving energy metabolism of muscles with impaired oxidative capacity.

Intermittent warm blood cardioplegia preserves myocardial beta-adrenergic receptor function.

BACKGROUND: Left ventricular dysfunction is frequently observed in patients after hypothermic cardioplegic arrest, and often inotropic intervention is necessary for patients to be successfully weaned from cardiopulmonary bypass (CPB). A myocardial beta-adrenergic receptor (beta AR) desensitization has been noted to occur after hypothermic CPB in patients undergoing coronary artery bypass grafting. This randomized study was undertaken to determine the effect of cardioplegic solution temperature on cardiac beta ARs. METHODS: Two groups of patients (20 patients in each) scheduled for elective coronary artery bypass grafting underwent CPB with either intermittent warm or cold blood cardioplegia. The density of the beta ARs, the proportion of beta 1- to beta 2-adrenergic receptors, and the beta AR coupling capacity to adenylate cyclase were determined in specimens of the right atrial tissue at baseline, during CPB, and after discontinuation of CPB. Plasma concentrations of catecholamines were also measured in both arterial and coronary sinus samples. RESULTS: In both cardioplegia groups, no significant modification in either the beta AR density or the proportion of beta 1- to beta 2-adrenergic receptors was detected. However, a significant decrease in adenylate cyclase activity after stimulation with isoproterenol was observed in the cold blood cardioplegia group during CPB (p < 0.01) and 30 minutes after its discontinuation (p < 0.05). Moreover, a significant decrease in adenylate cyclase activity during CPB was detected in this group after stimulation with sodium fluoride (p < 0.05), but this pattern was found to be completely reversed by 30 minutes after discontinuation of CPB. No modification in the basal or stimulated adenylate cyclase activity was observed in the warm blood cardioplegia group during or after CPB. CONCLUSIONS: Our results confirm the finding from previous studies of a cardiac beta AR desensitization after hypothermic cardioplegic arrest, and provide evidence of the advantages of intermittent warm blood cardioplegia in preserving the autonomic sympathetic function of the heart.

Complement and neutrophil activation during cardiopulmonary bypass: a randomized comparison of hypothermic and normothermic circulation.

OBJECTIVE: Activation of both complement and neutrophils has been demonstrated to be involved in many pathological reactions following cardiopulmonary bypass (CPB). The aim of the present study is to evaluate the effect of normothermic and hypothermic CPB on both complement and neutrophil activation. METHODS: Two groups of patients (n = 20 each) scheduled for elective coronary artery bypass grafting, underwent CPB with intermittent warm or cold blood cardioplegia. Plasma concentration of C3a, C5a and C5b-9, as well as nitro-blu tetrazolium (NBT) scores of circulating neutrophils were measured before anesthesia, 10 and 30 min after the beginning of CPB, and 8, 16 and 24 h, postoperatively. RESULTS: In both groups, CPB determined a significant complement activation, evidenced as a significant increase in plasma concentration of C3a, C5a and C5b-9. This in turn triggered the neutrophil activation, documented as a significant increase of NTB scores in circulating neutrophils at the end of CPB and in the early postoperative period. Interestingly, in the warm group the extent of both complement and neutrophil activation was significantly higher compared with the cold group during the whole sampling period. CONCLUSION: In conclusion, our study clearly demonstrates that warm CPB is associated with an increased ability to activate complement and neutrophils in patients undergoing coronary surgery.

Aortic valve replacement through a minimally invasive approach.

Minimally invasive cardiac surgery is rapidly gaining interest because of fast recovery, reduced morbidity, shorter hospital stay, lower costs, and better cosmetic results. Aortic valve surgery can be performed through a small (10- to 12-cm) transverse sternal incision, and femoro-femoral cannulation is used for cardiopulmonary bypass. Exposure of the ascending aorta is satisfactory. From 1 March through 30 September 1996, 7 patients underwent aortic valve replacement through this approach. The mean age of the 5 women and 2 men was 58.8 years. We used this technique mainly in patients with chronic obstructive pulmonary disease, diabetes, or obesity, in the absence of coronary artery disease. There was no mortality, nor was there reoperation for bleeding, stroke, or wound infection. All patients were extubated after 2 hours in intensive care and were discharged on the 4th postoperative day. Additional cases are needed to properly assess the correct indication and surgical technique.

Carotid endarterectomy and myocardial revascularization. A single stage procedure.

Carotid endarterectomy (CEA) and myocardial revascularization can be performed in a single procedure, performing CEA before or during cardio-pulmonary by-pass (CPB), or using a double stage approach. Over a 4 year period, 17 patients underwent CEA and coronary artery by-pass (CAB) with a single stage procedure. Fourteen patients (82.3%) were male, 3 (17.6%) were female. The mean age was 66.3 +/- 7.07. One patient (5.8%) had a previous neurological event (stroke); 5 patients (29.4%) had a previous transient ischemic attacks (TIA). The indications for the combined operations were CAD associated to unilateral internal carotid stenosis greater than 70% or 50% when symptomatic. In all patients CEA was performed after median sternotomy and heparinization, during CPB, with moderate hypotermia (30%C), performing CEA successively. One patient (5.8%) died of acute heart failure secondary to mediastinits. Minor neurological complications were present in 2 patients (11.7%) with signs of cerebral oedema. Myocardial infarction and late neurological deficit did not occur in any patient. We conclude that it is important, in the preoperative assessment of every patients with CAD, the screening for concomitant carotid vascular diseases, in order to avoid neurological complications during CPB, treating the two different diseases with a single stage approach, if carotid stenosis is greater than 70% or greater than 50% when symptomatic.

[Use of enoximone in the postoperative course of heart surgery]. / Impiego dell'enoximone nel decorso postoperatorio in cardiochirurgia.

The aim of this study was to evaluate the efficacy and safety of enoximone, an imidazolonic compound inhibiting cardiac phosphodiesterase III, during the postoperative period. The drug was administered prior to the usual stages of weaning the patient off extracorporeal circulation, to a group of 20 subjects who presented an ejection fraction of less than 35% following hemodynamic studies. Patients were randomly subdivided into 4 groups each of which received a different dose of enoximone according to the following protocol: Group A, 1 mg/kg bolus and slow infusion at 10 gamma/kg/min; Group B, 0.5 mg/kg bolus and slow infusion at 15 gamma/kg/min; Group C, 0.5 mg/kg bolus and slow infusion at 10 gamma/kg/min; Group D, slow infusion at 10 gamma/kg/min. The best results in hemodynamic terms and with regard to the positive inotropic and vasodilatory action of the drug in question were obtained in Group C. Increased cardiac output was observed in all patients within 120 minutes of enoximone administration and reduced systemic vascular resistance after approximately 6 hours of infusion. Special attention should be drawn to the use of the drug in patients who do not respond to conventional therapy due to its mechanism of action which is not dependent on beta receptors, thus enabling good results to be achieved even when these are down regulated. Special care must be taken however in administrating enoximone to platelet-deficient patients since the reduction of platelet levels is one of its collateral effect. Other collateral effects observed were: supraventricular arrhythmias and ventricular tachyarrhythmias.

Clinical experience with the transvenous Medtronic Pacer Cardioverter Defibrillator (PCD) System.

We review our experience with the transvenous Medtronic Pacer Cardioverter Defibrillator System (Model 7217B), a multifunction implantable pacer defibrillator combined with a transvenous lead system (Transvene). From April 1991 to October 1992, we implanted this device in 19 consecutive patients (11 men and 8 women; average age, 56.5 years). Nine patients (47.4%), 5 with coronary artery disease and 4 with dilated cardiomyopathy, had an ejection fraction of < 30%. The average operative time was 129 minutes. In 18 patients (94.7%), the transvenous lead system provided effective sensing, pacing, and defibrillation during intraoperative testing. In each of these cases, the defibrillation threshold was less than 18 J. In 1 patient (5.3%), it was necessary to switch to epicardial leads, which were implanted through a left thoracotomy. All patients were extubated in the recovery room. The average hospital stay was 8 days. There was no early mortality or morbidity. During a maximum follow-up period of 17 months (mean, 9.2 months), no sudden death occurred. The implantable system terminated 245 ventricular tachycardia episodes in 14 patients (73.7%) and 82 ventricular fibrillation episodes in 13 patients (68.4%). Two hundred eleven (86.1%) of the ventricular tachycardia episodes were resolved by antitachycardia pacing alone. In 2 patients (10.5%), the caval electrode became dislocated; repositioning of the electrode was followed by repeat defibrillation threshold evaluation. Our experience shows that the transvenous Medtronic Pacer Cardioverter Defibrillator System provides safe, effective treatment of ventricular tachyarrhythmias. Because the perioperative mortality and morbidity are extremely low, use of this device may be particularly beneficial in patients with a high operative risk. Moreover, the lower number of unpleasant therapeutic shocks should increase patient a acceptance of the device.

Myocardial revascularization in women.

To compare the results of coronary artery bypass in women and men, we reviewed our experience from January 1976 through June 1989. During this period, 170 women with coronary artery disease but with no other cardiac abnormalities underwent coronary artery bypass. We compared this group with a group of 150 men, matching them according to age, presence of angina, extent of disease, and surgical treatment. Preoperative clinical features, surgical data, and early and late results were analyzed. The operative mortality was similar between groups (2.9% for women vs 2.6% for men). The women, however, were more frequently overweight (54% vs 15%; p <0.001) and more often had the following: diabetes mellitus (34% vs 20%; p <0.01), a coronary artery diameter of <1.8 mm (64% vs 29%; p <0.001), poor saphenous vein quality (50% vs 16%; p <0.001), and incomplete revascularization (20% vs 4%; p <0.001). After a mean follow-up of 6 years, the women also had a higher incidence of recent-onset myocardial infarction (31% vs 12%; p <0.001) and a greater tendency to be symptomatic (48% vs 19%; p <0.001). The 12-year cumulative survival rates were similar in both groups (76.2% for women vs 77.1% for men). According to logistic regression analysis of the significantly different variables, the only independent determinants of postoperative asymptomatic status were satisfactory coronary artery caliber, good saphenous vein quality, and complete revascularization. We conclude that poorer functional results after coronary artery bypass surgery in women may be caused by a poorer quality of revascularization, which in turn is a result of smaller coronary artery diameter, worse distal runoff, and less satisfactory vein quality.

Late innominate vein thrombosis. Unusual complication following sternal closure.

An unusual complication of the median sternotomy is reported. A 37-year-old male experienced a left innominate vein thrombosis 20 months after surgery. The combined treatment consisting of local infusion with Urokinase, surgical removal of the wire and balloon catheter dilatation, was completely successful.

[Isolated traumatic rupture of the ascending aorta. Clinical case and review of the literature]. / Rottura traumatica isolata dell'aorta ascendente. Caso clinico e revisione della letteratura.

Rupture of the descending aorta after severe blunt chest trauma is a well recognised injury. Instead, isolated traumatic rupture of the ascending aorta is rarely diagnosed, with only five cases reported in the literature. A case of isolated traumatic rupture of the ascending aorta is here reported and the role of medical treatment is described.

False aneurysm from the aortic vent site.

False aneurysm from the aortic vent site is an uncommon complication following open heart surgery. An ascending aorta false aneurysm developed in a patient four months after mitral and aortic valve replacement. Extensive adhesions precluded aortic dissection and cross-clamping. Femoro-femoral cannulation, low flow, low pressure, and low temperature cardiopulmonary by-pass was used. The aneurysm was resected and then repaired with a Dacron patch. A Foley catheter was placed in the ascending aorta through the defect to obtain a bloodless field. This surgical approach can be useful in managing this difficult situation.

[Serial evaluation by effort test of the effects of coronary artery bypass on effort angina (author's transl)]. / Valutazione seriata mediante prove da sforzo degli effetti della chirurgia coronarica sul'angina stabile da sforzo.

To evaluate the duration of favourable effects of coronary artery bypass (CAB) on exercise-induced angina (A), 58 patients: 13 with single 21 with double and 24 with triple vessel disease, were studied. All patients underwent CAB for stable angina on effort. Patients underwent exercise testing (ET) before surgery at one, two and three years. Heart rate peak (HR), HR x systolic blood pressure peak (DP), work load (W), exercise-induced ST segment depression (ST) and incidence of A were evaluated; the results of ET before surgery were compared with those found after CAB. Our findings show that HR, DP, W and ST were significantly improved by surgery for at least 3 years. The lowest incidence of A was found at one year ET (20.6%), while it increased at two years (27,5%) and three years ET (37.9%). Most patients with A had angiographic evidence of left ventricular abnormal wall motion and ec-graphic signs of previous myocardial infarction. Our data indicate that serial exercise testing can objectively monitor the results of CAB. Most patients show an improved exercise tolerance for up to 3 years after CAB. Some patients, with more extensive CAD, showed a progressive deterioration of the clinical pattern and a decrease of the exercise tolerance.