Impact of preoperative left ventricular ejection fraction on long-term survival after aortic valve replacement for aortic stenosis.

BACKGROUND: The survival of patients who undergo aortic valve replacement (AVR) for severe aortic stenosis with reduced preoperative ejection fractions (EFs) is not well described in the literature. METHODS AND RESULTS: Patients undergoing AVR for severe aortic stenosis were analyzed using the Northern New England Cardiovascular Disease Study Group surgical registry. Patients were stratified by preoperative EF (≥50%, 40%-49%, and <40%) and concomitant coronary artery bypass grafting. Crude and adjusted survival across strata of EF was estimated for patients up to 8 years beyond their index admission. A total of 5277 patients underwent AVR for severe aortic stenosis between 1992 and 2008. There were 727 (14%) patients with preoperative EF <40%. Preoperative EF had minimal effect on postoperative morbidity. There was no difference in 30-day mortality across EF strata among the isolated AVR cohort. Preserved EF conferred 30-day survival benefit among the AVR+coronary artery bypass grafting population (EF≥50%, 96%; EF<40%, 91%; P=0.003). Patients with preserved EF had significantly improved 6-month and 8-year survival compared with their reduced EF counterparts. CONCLUSIONS: Survival after AVR or AVR+coronary artery bypass grafting was most favorable among patients with preoperative preserved EF. However, patients with mild to moderately depressed EF experienced a substantial survival benefit compared with the natural history of medically treated patients. Furthermore, minor reductions of EF carried equivalent increased risk to those with more compromised function suggesting patients are best served when an AVR is performed before even minor reductions in myocardial function.

Limited blood transfusion does not impact survival in octogenarians undergoing cardiac operations.

BACKGROUND: We previously reported that transfusion of 1 to 2 units of red blood cells (RBCs) confers a 16% increased hazard of late death after cardiac surgical treatment. We explored whether a similar effect existed among octogenarians. METHODS: We enrolled 17,026 consecutive adult patients undergoing cardiac operations from 2001 to 2008 in northern New England. Patients receiving more than 2 units of RBCs or undergoing emergency operations were excluded. Early (to 6 months) and late (to 3 years, among those surviving longer than 6 months) survival was confirmed using the Social Security Death Index. We estimated the relationship between RBCs and survival, and any interaction by age (<80 years versus ≥80 years) or procedure. We calculated the adjusted hazard ratio (HR), and plotted adjusted survival curves. RESULTS: Patients receiving RBCs had more comorbidities irrespective of age. Patients 80 years of age or older underwent transfusion more often than patients younger than 80 years (51% versus 30%; p<0.001). There was no evidence of an interaction by age or procedure (p>0.05). Among patients younger than 80 years, RBCs significantly increased a patient's risk of early death [HR, 2.03; 95% confidence interval [CI], 1.47, 2.80] but not late death 1.21 (95%CI, 0.88, 1.67). RBCs did not increase the risk of early [HR, 1.47; 95% CI, 0.84, 2.56] or late (HR, 0.92 95% CI, 0.50, 1.69) death in patients 80 years or older. CONCLUSIONS: Octogenarians receive RBCs more often than do younger patients. Although transfusion of 1 to 2 units of RBCs increases the risk of early death in patients younger than 80 years, this effect was not present among octogenarians. There was no significant effect of RBCs in late death in either age group.

Effect of prior cardiac operations on survival after coronary artery bypass grafting.

BACKGROUND: We examined a recent regional experience to determine the effect of a prior cardiac operation on short-term and midterm outcomes after coronary artery bypass grafting (CABG). METHODS: We identified 20,703 patients who underwent nonemergent CABG at 8 centers in northern New England from 2000 to 2008, of whom 818 (3.8%) had undergone prior cardiac operations. Prior CABG using a minimal or full sternotomy was considered a prior sternotomy. Survival data out to 4 years were obtained from a link with the Social Security Administration Death Index. Hazard ratios were estimated using a Cox proportional hazards regression model, and adjusted survival curves were estimated using inverse probability weighting. In a separate analysis, 1,182 patients were matched 1:1 by a patient's propensity for having undergone prior CABG. RESULTS: Patients with prior sternotomies had a greater burden of comorbid diseases and increased acuity and had a greater likelihood of returning to the operating room for bleeding and low cardiac output failure. Prior sternotomy was associated with an increased risk of death out to 4 years for patients undergoing CABG, with an unmatched hazard ratio of 1.34 (95% confidence interval, 1.10 to 1.64) and a matched hazard ratio of 1.36 (95% confidence interval, 1.01 to 1.81). CONCLUSIONS: Analyses of our recent regional experience with nonemergent CABG showed that a prior cardiac operation was associated with a nearly twofold increased hazard of death at up to 4 years of follow-up.

Detection and elimination of microemboli related to cardiopulmonary bypass.

BACKGROUND: Neurobehavioral impairment is a common complication of coronary bypass surgery. Cerebral microemboli during cardiopulmonary bypass (CPB) are a principal mechanism of cognitive injury. The aim of this work was to study the occurrence of cerebral embolism during CPB and to evaluate the effectiveness of evidence-based CPB circuit component and process changes on the exposure of the patient to emboli. METHODS AND RESULTS: M-Mode Doppler was used to detect emboli in the inflow and outflow of cardiopulmonary circuit and in the right and left middle cerebral arteries. Doppler signals were merged into a single display to allow real-time associations between discrete clinical techniques and emboli detection. One hundred sixty-nine isolated coronary artery bypass grafting (CABG) patients were studied between 2002 and 2008. There was no statistical difference in median microemboli detected in the inflow of the CPB circuit, (Phase I, 931; Phase II, 1214; Phase III, 1253; Phase IV, 1125; F [3,158]=0.8, P=0.96). Significant changes occurred in median microemboli detected in the outflow of the CPB circuit across phases, (Phase I, 702; Phase II, 572; Phase III, 596; Phase IV, 85; F [3,157]=13.1, P<0.001). Significant changes also occurred in median microemboli detected in the brain across phases, (Phase I, 604; Phase II, 429; Phase III, 407; Phase IV, 138; F [3,153]=14.4, P<0.001). Changes in the cardiopulmonary bypass circuit were associated with an 87.9% (702 versus 85) reduction in median microemboli in the outflow of the CPB circuit (P<0.001), and a 77.2% (604 versus 146) reduction in microemboli in the brain (P<0.001). CONCLUSIONS: Changes in CPB techniques and circuit components, including filter size and type of pump, resulted in a reduction in more than 75% of cerebral microemboli.

Heparin-induced thrombocytopenia with thrombosis syndrome managed with plasmapheresis.

Heparin-induced thrombocytopenia with thrombosis syndrome is an antibody-mediated disorder that has a high mortality in cardiac surgical patients in spite of early diagnosis and management with direct thrombin inhibitors. Plasmapheresis, an extracorporeal technique that has been designed for the removal of large molecular weight substances from the plasma, can remove the offending antibodies from these desperately ill patients. We describe a case of a postoperative cardiac surgery patient with heparin-induced thrombocytopenia with thrombosis syndrome and multi-system failure who was dependent upon a left ventricular assist device. He was treated successfully with plasmapheresis with recovery of his platelet count from 25,000/microl to over 200,000/microl, along with multi-organ recovery. This patient survived because of plasmapheresis. Removing the antibodies to the heparin-platelet factor four complex with plasmapheresis is an effective strategy to treat these patients. We believe that the use of plasmapheresis as a bail-out procedure in these often desperately ill post-operative cardiac surgical patients who have heparin-induced thrombocytopenia with thrombosis syndrome could be lifesaving.

Successful management of a left ventricular assist device malfunction in an outpatient setting.

Heart disease kills as many people as nearly all other causes of death combined. Chronic, progressive, end-stage heart failure results in substantial health care costs and immeasurable suffering for both individuals in particular and society in general. Ventricular assist devices are having an increasing role in supporting patients with severe circulatory compromise. These devices provide support and make it possible for patients to be discharged from the hospital and returned to their communities. System failures and device malfunctions do occur and are the most common cause of death for patients on device support. We present a device malfunction involving a HeartMate XVE Bridge to Transplant that occurred while the patient was at his home, > 100 mi. from our center. The patient was placed on a HeartMate after a re-operative coronary artery bypass surgery. He was discharged to his home on day 43 after device implant. On the 447th post-operative day, two "Red Heart" alarms occurred. After initiating hand pumping of the device, the patient's companion contacted our center, and the local Emergency Medical Service was activated. The patient was transported by helicopter to the Maine Medical Center, where he was placed on a backup pneumatic console and subsequently transferred to a Boston transplant center. The patient subsequently underwent cardiac transplantation. It is imperative to have a definitive strategy and clear support plan to address device malfunctions and system failures. Considering the growing number of ventricular assist device patients discharged home, these occurrences will be more common outside of the hospital setting. Education of clinicians, patients, and their companions, as well as local rescue teams and community hospitals, is essential for successful outcomes and continued quality of life.