What factors influence the results of coronary artery bypass grafting in aged patients?

AIM: Early and late results were studied in order to improve the indication for coronary artery bypass grafting (CABG) and to enhance METHODS: A total of 1 973 patients aged 70 years and older who had undergone isolated CABG were studied. Elective operations (EL) were performed in 1 716 patients and 257 patients underwent urgent or emergency operations (UR/EM). Patients were divided into two groups; 104 patients aged 80 years and older (Oct. Group) and 1 869 patients of septuagenarians (Sept. Group). There were no differences between the groups in the number of diseased vessels. RESULTS: Total operative mortality rates in the Oct. and the Sept. groups were 7% and 4%, respectively. The operative mortality of elective surgery was 4% in both groups. The operative mortality of UR/EM CABG was significantly higher in the Oct. group than in the Sept. group (21% vs 6%). Operative mortality was significantly higher in patients with preoperative poor (<49%) left ventricular ejection fraction (LVEF) than in patients with higher (>50%) LVEF (6% vs 3%). Among preoperative risk factors, diabetes mellitus and peripheral vascular disease were significant contributory factors to operative death. In the follow-up study, 70% patients of the Oct. group and 72% patients of the Sept. group survived. Preoperative number of diseased vessels and number of CABG grafts did not influence the early and late CONCLUSION: Preoperative poor LVEF, diabetes mellitus and peripheral vascular disease were significant contributory factors to operative death. When feasible, CABG in octogenarians should be performed electively.

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.

Combined endocardial and epicardial radiofrequency ablation of right and left atria in the treatment of atrial fibrillation.

BACKGROUND: The maze procedure and its modifications have been successful in treating atrial fibrillation (AF), at the expense of longer procedure times and increased morbidity. This study evaluated the early results of using radiofrequency ablation as a surgical adjunct in treating AF. METHODS: Twenty-six patients, with established or frequent intermittent AF, who were undergoing various cardiac surgical procedures, were enrolled. During their operations, the patients underwent intraoperative left and right atrial radiofrequency ablation lesions using a handheld flexible probe. Patients were followed up with echocardiography and Holter monitoring. RESULTS: All 26 patients were weaned off cardiopulmonary bypass in sinus rhythm. There were 2 early noncardiac deaths in high-risk patients; 23 surviving patients (95%) remained in sinus rhythm at a mean follow-up of 175 days (range 96 to 400 days). Three patients were defibrillated into sinus rhythm 30, 40, and 60 days after their operation. Test epicardial lesions on the right atrial appendage in 12 patients showed full-thickness coagulation of tissue in 10 (83%). CONCLUSIONS: A combined endocardial and epicardial set of radiofrequency lesions in both atria abolished AF in most patients at 6 months and facilitated easy conversion of recurrent AF into sinus rhythm. The transmural nature of the epicardial lesions has implications for further development.

Exclusive Y graft operation for multivessel coronary revascularization.

BACKGROUND: The pedicled (in-situ) left internal mammary artery grafted to the left anterior descending artery has a very high late patency and reduces late mortality following coronary artery bypass surgery. A technique is described which achieves total arterial revascularization in patients with multivessel coronary disease and which is also entirely pedicled. METHODS: Using the left internal mammary artery and radial artery joined as a composite Y graft, all coronary territories may be grafted. RESULTS: One in-hospital death from 464 patients (0.2%) occurred. Age (mean +/- standard error) was 64.7 +/- 0.5 years and number of distal anastomoses 3.4 +/- 0.04. Of 1,681 patients from Royal Melbourne Hospital, 346 had this operation. Comparison found no preoperative selection bias and no postoperative differences in complications. Actuarial survival was 0.98 +/- 0.01 at 36.1 +/- 0.3 months. CONCLUSIONS: Total arterial revascularization may be performed using the left internal mammary artery and radial artery as a composite Y graft. There was no increase in complications. This technique preserves the left internal mammary artery to left anterior descending artery graft.

Ventricular containment as an adjunctive procedure in ischemic caridomyopathy: early results.

BACKGROUND: Ventricular containment with custom-made polyester mesh is an evolving technique that has been studied in experimental animals with heart failure with good results. METHODS: Five patients with symptomatic heart failure and ischemic cardiomyopathy were enrolled in a Phase I study, and underwent ventricular containment with custom-made polyester mesh along with coronary artery bypass grafting. Four patients had additional ventricular reconstruction of large myocardial scars. RESULTS: All patients were in NYHA functional class III at the time of their operation with a mean ejection fraction of 27.4%+/-6.6%. There were no deaths. Mean postoperative ejection fraction was 35.1%+/-12.6% (p = 0.16). Left ventricular end-diastolic diameter fell from 63.2+/-1.6 mm preoperatively to 50.6+/-5 mm, postoperatively (p = 0.004). There was no evidence of diastolic dysfunction or pericardial constriction on intra- or postoperative echocardiography. At a mean follow-up of 180 days all patients were in NYHA class I with no readmissions for heart failure. Repeat coronary angiography at 6 months revealed patent grafts in all patients. CONCLUSIONS: Ventricular containment with a customized mesh may be performed safely as an adjunct to conventional cardiac operation in patients with symptomatic heart failure. Longer follow-up with an expansion of the study will help delineate the long-term effects of this therapy.

High lactate predicts the failure of intraaortic balloon pumping after cardiac surgery.

BACKGROUND: Despite the use of intraaortic balloon pump (IABP) support in complex cardiac surgical patients, morbidity and mortality rates are high. More advanced mechanical cardiovascular support should be considered in those patients who are highly likely to die despite IABP support. We sought to identify early, readily available prognostic markers for patients receiving IABP support. METHODS: A retrospective analysis was performed on 39 patients requiring IABP support following cardiac surgery for more than 2 years. The accuracy and predictive ability of multiple potential markers of mortality were statistically assessed. RESULTS: Sixty-seven percent of the patients were successfully weaned from IABP support and 46% survived to hospital discharge. Serious complications occurred in 13% of patients. Serum lactate more than 10 mmol/L in the first 8 hours of IABP support predicted a 100% mortality. Base deficit more than 10 mmol/L, mean arterial pressure less than 60 mm Hg, urine output less than 30 mls/h for 2 hours, and dose of epinephrine or norepinephrine more than 10 microg/min were other highly predictive prognostic markers. CONCLUSIONS: Morbidity and mortality rates remain high despite IABP support following cardiac surgery. Mortality can be predicted by the presence of elevated serum lactate, elevated base deficit, hypotension, oliguria and large vasopressor doses, any of which should prompt appropriate consideration as to other mechanical cardiovascular support.

Metabolic changes and myocardial injury during cardioplegia: a pilot study.

BACKGROUND: The timing, nature, and severity of both increased cardiac troponin I (cTn-I) levels and myocardial injury during ischemic arrest with cardioplegia are unknown. To define them more accurately, we studied myocardial metabolic activity and the release of markers of myocardial cell injury into the coronary sinus before, during, and after cardioplegia. METHODS: We simultaneously measured creatine kinase, creatine kinase-MB, cTn-I, lactate, phosphate, and blood gases in coronary sinus and systemic arterial blood from 12 patients before cardiopulmonary bypass, after removal of the aortic cross-clamp, and after discontinuation of cardiopulmonary bypass. We also measured coronary sinus flow and transmyocardial fluxes of all analytes and calculated myocardial oxygen consumption, myocardial carbon dioxide production, and myocardial energy expenditure. RESULTS: Myocardial lactate release increased 10-fold after removal of the aortic cross-clamp (p = 0.012) and was accompanied by a surge in myocardial phosphate uptake (p = 0.056). These events were associated with only partial cardioplegia-induced suppression of myocardial oxygen consumption (p = 0.0047), myocardial carbon dioxide production (p = 0.0022), and myocardial energy expenditure (p = 0.0029). Simultaneously, coronary sinus cTn-I levels increased from a mean of 0.76 to 2.43 ng/mL after removal of the aortic cross-clamp, and 2.51 ng/mL after cardiopulmonary bypass (p = 0.014), leading to an increase in arterial cTn-I concentration from 0.18 to 0.98 and 3.01 ng/mL (p = 0.0002). Thus, cTn-I release across the myocardium was absent at baseline, became detectable (p = 0.012) after removal of the aortic cross-clamp, and correlated with cross-clamp and pump times. Similar changes occurred with creatine kinase-MB. CONCLUSIONS: Metabolic myocardial stress occurs during ischemic arrest with cardioplegia and is associated with inadequate suppression of metabolism and with a surge in cTn-I and creatine kinase-MB release, which is maximal after removal of the aortic cross-clamp. These changes are likely to represent structural myocardial cell injury.

Ulnar artery as a coronary bypass graft.

BACKGROUND: The ulnar artery has been used as a coronary bypass graft in 8 patients when it was deemed unsafe to harvest the radial artery after evaluation of the arterial circulation in the forearm and hand. METHODS: The ulnar artery was removed from the lower three quarters of the forearm, along with its satellite veins. Dissection was commenced distally near the wrist and extended proximally to where the ulnar artery passed between the two heads of origin of the flexor digitorum superficialis. The artery was divided distally above the wrist joint and proximally at a point immediately below the origin of the common interosseus artery. RESULTS: Ten ulnar arteries were removed for use as coronary artery bypass grafts; two were rejected, one because of severe calcification and the other because of atherosclerotic occlusion. The remaining eight ulnar arteries were grafted successfully to coronary arteries other than the left anterior descending. No early hand or cardiac complications were observed. CONCLUSIONS: The ulnar artery is an alternative coronary artery bypass graft that may be used when the radial artery is dominant and cannot be removed without risk. The ulnar artery is in close proximity to the ulnar nerve and harvesting has the potential to injure the nerve. Therefore, until the use of the ulnar artery has been more fully evaluated it should be used only when other options have been exhausted.

An extracorporeal membrane oxygenation-based approach to cardiogenic shock in an older population.

BACKGROUND: We investigated the efficacy of an integrated system of advanced supportive care based on extracorporeal membrane oxygenation (ECMO) in older patients with an estimated mortality of more than 90% to establish whether its use is justifiable. METHODS: Treatment was provided by cardiac surgeons and critical care physicians and included the following key elements: (1) ECMO, (2) early application of continuous venovenous hemofiltration, (3) inhaled nitric oxide, (4) maintenance of perfusion pressure with norepinephrine, (5) maintenance of pulmonary blood flow by ventricular filling with intravenous colloids, (6) avoidance of early postoperative anticoagulation, (7) frequent use of transesophageal echocardiography, and (8) low tidal volume ventilation. Demographic features, intraoperative details, postoperative course, ECMO weaning rate, morbidity, survival to hospital discharge, and the quality of life of survivors were recorded. RESULTS: Seventeen consecutive patients (median age, 69 years) with refractory cardiogenic shock were studied. The median duration of ECMO was 86 hours (20 to 201 hours). Eleven patients (65%) were successfully weaned from ECMO. Seven patients (41%) survived to discharge. The major causes of morbidity were bleeding and leg ischemia. All patients who survived to discharge were alive and well at follow-up (median, 21 months) and reported a satisfactory quality of life. CONCLUSIONS: An ECMO-based approach can be used with acceptable results in the treatment of refractory cardiogenic shock, even in older patients.

Hemofiltration during cardiopulmonary bypass for high risk adult cardiac surgery.

AIMS: The role of hemofiltration (HF) during cardiopulmonary bypass (CPB) in adult cardiac surgery is controversial. It may be beneficial during prolonged CPB in high-risk surgery. Accordingly, we sought to compare two groups of patients undergoing high-risk cardiac surgery with or without HF. METHODS: One hundred and eighteen patients who underwent complex cardiac surgical procedures during a 12-month period were divided into two groups. Group I (n=61) comprised patients who were treated with hemofiltration during CPB. Group II (n=57) were not filtered. Estimated risk of death, standard demographic, clinical and surgical features were obtained and predetermined outcomes were studied. Statistical comparisons were made. RESULTS: Age, procedure times and mortality rates were similar in both groups. The mean volume of fluid removed in group I was 3.4 L. The preoperative mean Parsonnet score was 24.8 in group I and 22.5 in group II (ns). Postoperative serum hemoglobin, hematocrit, platelet, and albumin levels were all significantly higher in group I patients (p=0.0015) indicating hemoconcentration. Post-operative chest drainage showed a trend toward decreased post-operative bleeding in group I (p=0.065). Postoperative pleural effusions requiring chest tube drainage were significantly less in group I (9.8% vs. 29.8% 6; p = 0.0062). The incidence of lung infection was also decreased from 26.3% to 13.1% (p=0.05). Operative mortality was similar in both groups (11.4% in group 1, 10.5% in group II, ns). CONCLUSION: Hemofiltration during CPB attenuates postoperative anemia, thrombocytopenia and hypoalbuminemia, may reduce post-operative bleeding and appears to decrease post-operative pulmonary complications.

The mid-term results of ventricular containment (ACORN WRAP) for end-stage ischemic cardiomyopathy.

The acorn cardiac support device (ACSD) is a device designed to treat heart failure by containing the heart to prevent further dilation. Six patients with symptomatic heart failure due to ischemic cardiomyopathy were treated surgically with ACSD. All patients simultaneously underwent coronary artery bypass grafting. Ventricular reconstruction was also performed in 5 of the 6 patients. We followed up the patients for 12 months postoperatively, monitoring the left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), mitral regurgitation, and NYHA classification. Both the LVEDD and LVESD were significantly improved one month postoperatively (from 63.2 to 50.6 mm, p=0.004, and from 51.6 to 39.5 mm, p=0.025, respectively). These dimensions did not change significantly over the next 11 months. NYHA functional class improved significantly from a mean of 3 to 1.4 at 12 months (p=0.012). Mitral regurgitation improved from a mean of 2.7 preoperatively to 1.4 at 12 months and the average LVEF also improved from 27% preoperatively to 35.9% at 12 months after surgery. However these latter two results were not statistically significant. There were no late deaths and no readmissions for heart failure. Repeat coronary angiography at 6 months revealed patent grafts in all patients. The mid-term results of ACSD for patients with symptomatic heart failure suggest that ventricular containment may be useful for preventing further cardiac dilation in patients with ischemic cardiomyopathy. Randomized, long-term studies are needed to assess the efficacy and possible role of ASCD in the future management of heart failure.