James A. Magovern

A model for predicting transfusion after coronary artery bypass grafting

BACKGROUND Blood conservation has become an important issue in cardiac surgery. This study was undertaken to determine if the need of blood transfusion could be predicted from preoperative patient variables. METHODS From January 1, 1992, to December 31, 1993, 2,033 patients having isolated coronary artery bypass grafting procedures were studied; 1,446 (71%) were male and 587 (29%), female. The mean age was 65.1 +/- 9.9 years (range, 31 to 88 years). Emergency operation, urgent operation, and reoperations were done in 78 (4%), 188 (9%), and 189 (9%) patients, respectively. In the entire group, 1,245 (61%) received transfusion during hospitalization, and 788 (39%) did not. Logistic regression analysis was used to construct a model that predicted the need of transfusion of packed red blood cells after coronary artery bypass grafting. A transfusion risk score was constructed by assigning points to independent predictive factors on the basis of the logistic regression coefficient and the odds ratio. Preoperative predictors of transfusion were emergency operation, urgent operation, cardiogenic shock, catheterization-induced coronary occlusion, low body mass index, left ventricular ejection fraction lower than 0.30, age greater than 74 years, female sex, low red cell mass, peripheral vascular disease, insulin-dependent diabetes, creatinine level greater than 1.8 mg/dL, albumin value lower than 4 g/dL, and redo operation. RESULTS The mean transfusion risk score for patients receiving 0, 1 to 4, and greater than 4 units of packed red blood cells was 2.3 +/- 0.9, 5.2 +/- 3.0, and 9.6 +/- 3.5, respectively (p = 0.001). Patients with a score higher than 6 had a 95% transfusion incidence. The predictive model was validated on 422 patients having coronary artery bypass grafting from January 1 to May 31, 1994. The observed rates of the validation group fell within the 95% confidence intervals of the predicted rates. CONCLUSIONS These data demonstrate that readily available patient variables can predict patients at risk for transfusion. Routine use of aprotinin and other adjustments of cardiopulmonary bypass should be considered to reduce transfusion in high-risk patients.

Aortic valve replacement and combined aortic valve replacement and coronary artery bypass grafting: predicting high risk groups

To determine which groups of patients are at highest risk for operative or late mortality, 259 consecutive patients who underwent operation between 1978 and 1984 were studied; 170 underwent aortic valve replacement and 89 underwent aortic valve replacement combined with coronary artery bypass grafting. Multivariate analysis of risk factors selected emergency operation and patient age older than 70 years as the strongest predictors for operative death. Although patients having aortic valve replacement and coronary artery bypass grafting had a higher operative mortality rate (13.5 versus 3.5%), the combined operation had no independent predictive effect on early or late results. At a mean follow-up time of 48 months after surgery, 72% of the survivors of operation were living, 10% were lost to follow-up and 18% were dead. Seventy-seven percent of long-term survivors were in New York Heart Association functional class I or II. The incidence of thromboembolism, paravalvular leak, bacterial endocarditis and hemorrhage each occurred at a rate of less than 1% per patient-year. The factors associated with late death were preoperative age, male sex, left ventricular end-diastolic pressure, cardiac index and functional class. Despite an increase in operative mortality, patients undergoing emergency operation were not at higher risk of late death. Operative mortality is concentrated among several high risk groups. For patients undergoing elective operation, operative mortality is low, especially if the patient is less than 70 years old. Late results are good for all groups of patients undergoing operation, including those who are at greater risk of dying at operation.

Extracorporeal membrane oxygenation: Preliminary results in patients with postcardiotomy cardiogenic shock

Long-term survival at our institution for postcardiotomy cardiogenic shock patients supported with the BioPump is 36% (29/80 patients). A heparin-coated extracorporeal membrane oxygenator (ECMO), first introduced in 1991, may reduce organ injury associated with cardiopulmonary bypass. The device can be employed rapidly because it connects directly to the cardiopulmonary bypass cannula. In an effort to improve our results in the treatment of postcardiotomy cardiogenic shock, we used ECMO in 21 patients with this syndrome and accompanying complications. The patients were divided into three groups: group 1, ECMO after coronary artery bypass grafting; group 2, ECMO after mitral valve operation; and group 3, ECMO after open heart operation with prolonged cardiac arrest. Survival in group 1 was 80% with 12 of 14 patients discharged to home. All three deaths were caused by cardiac failure. Bleeding complications in this group were moderate. There was no evidence of disseminated intravascular coagulation, and levels of fibrin split products remained within the normal range. Postoperative complications included stroke (2), renal failure (1), mediastinitis (1), and prolonged respiratory failure (6). Mortality in group 2 was 100%. The major problem limiting recovery was left ventricular distention secondary to inadequate left ventricular decompression. Mortality in group 3 was 100%; all 4 died of brain death. Extracorporeal membrane oxygenation without left ventricular drainage clearly is not effective in patients undergoing mitral valve operations as it does not effectively decompress the left ventricle, but it was highly effective in treating postcardiotomy cardiogenic shock in our coronary artery bypass grafting patients. Extracorporeal membrane oxygenation also proved to be safe as the patient-related complications of stroke, renal failure, and mediastinitis were low. Our preliminary success with heparin-coated ECMO now needs to be confirmed by studies from other centers with larger groups of patients.

Prolonged open sternotomy and delayed sternal closure after cardiac operations

Maintenance of an open sternotomy (OS) after a complicated cardiac operation is an adjunct in the treatment of the severely impaired heart. We hypothesized that predictors of the timing, morbidity, and prognosis of delayed sternal closure (DSC) could be determined by intensive case review. Prolonged OS was used in 107 of 6,030 adult open heart patients (1.8%) between 1987 and 1991. Indications for OS were hemodynamic instability (40), myocardial edema (18), intractable bleeding (23), relentless arrhythmias (9), and ventricular assist devices (17). Delayed sternal closure was carried out in 75 of 107 patients at a mean of 3.4 +/- 0.3 days after OS. Fifty of these 75 (67%) survived and were discharged an average of 43 +/- 6 days after closure. Fifty-seven patients died: 32 before DSC at 3.7 +/- 0.8 days after OS and 25 after DSC at 27 +/- 4 days after OS. Baseline cardiac index (1.7 +/- 0.1 L.min-1.m-2) improved an average of 1.0 +/- 0.1 L.min-1.m-2 after OS (p less than or equal to 0.001) and remained stable through DSC (2.5 +/- 0.3 L.min-1.m-2) and late (9 +/- 0.7 days) follow-up (2.8 +/- 0.1 L.min-1.m-2). Delayed sternal closure in patients without ventricular assist devices was significantly more likely to be successful (45/63 versus 9/27; p less than 0.002) when carried out after the onset of a negative daily fluid balance. Sternal infection occurred in 4 of 75 (5%) patients after DSC and was associated with bleeding as an indication for OS (3/15 versus 1/60; p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Morbidity, cost, and six-month outcome of minimally invasive direct coronary artery bypass grafting

BACKGROUND Minimally invasive direct coronary artery bypass grafting (MIDCABG) promises to reduce the morbidity of coronary bypass, but this has not been proved. METHODS This retrospective study compares the morbidity, mortality, cost, and 6-month outcome of patients less than 80 years old undergoing elective left internal mammary artery to left anterior descending artery bypass grafting via MIDCABG (n = 60) or sternotomy (n = 55) between January 1995 and December 1996. There were no differences between the groups in mean age, sex distribution, or preoperative risk level. The left internal mammary artery was mobilized from the fifth costal cartilage to the subclavian artery in all patients. The anastomoses were done with a beating heart in the MIDCABG group and with cardioplegic arrest in the sternotomy group. RESULTS There were no operative deaths in either group. The MIDCABG patients had a lower transfusion incidence (10/60 [17%] versus 22/55 [40%]; p< or =0.02) and a shorter postoperative intubation time (2.1+/-4.2 versus 12.6+/-9 hours; p< or =0.0001). One patient in each group was reexplored for bleeding. Three sternotomy patients (3/55, 5%) required ventilatory support for greater than 48 hours, but no MIDCABG patient was ventilated for more than 24 hours. Median postoperative length of stay was 4 days for MIDCABG and 7 days for sternotomy. Estimated hospital costs were

Operation for congestive heart failure: transplantation, coronary artery bypass, and cardiomyoplasty.

11,200+/-3100 for MIDCABG and

Clinical cardiomyoplasty: Preoperative factors associated with outcome

15,600+/-4200 for CABG (p < 0.001). The reduced morbidity and cost of MIDCABG was found mostly in high-risk patients. At 6-month follow-up, 5 MIDCABG patients (5/60, 8%) had evidence of recurrent ischemia involving the left anterior descending artery, primarily the result of anastomotic stricture. CONCLUSIONS This analysis shows that MIDCABG reduces the initial morbidity and cost of coronary bypass, but some patients require subsequent reintervention. Long-term follow-up is needed before MIDCABG can be judged better than traditional bypass, but the initial results are promising, especially in high-risk patients.

Risks of Mitral Valve Replacement and Mitral Valve Replacement with Coronary Artery Bypass

Transplantation is effective therapy for congestive heart failure (CHF), but few donors are available and many patients are not candidates. We have therefore developed a surgical approach to CHF that offers several options. Patients with no medical or psychosocial contraindications are listed for heart transplantation (HT). Patients with ischemia on thallium scan and operable vessels have coronary artery bypass grafting (CABG). Patients who are not candidates for either of these options are evaluated for cardiomyoplasty (CMP). One hundred nineteen patients have now had operation for CHF: 61 had HT, 27 had CABG, and 31 had CMP. The mean ages of the three groups were 51 +/- 1 years, 59 +/- 3 years, and 56 +/- 2 years, respectively. Preoperative pulmonary capillary wedge pressure was 22 +/- 1.1 mm Hg in the HT group, 20 +/- 2.9 mm Hg in the CABG group, and 19 +/- 1.9 mm Hg in the CMP group. Left ventricular ejection fraction improved in operative survivors in each group: 0.23 +/- 0.01 to 0.69 +/- 0.01 for the HT group, 0.31 +/- 0.01 to 0.39 +/- 0.02 for the CABG group, and 0.26 +/- 0.01 to 0.33 +/- 0.03 for the CMP group (p < 0.01). The operative mortality rate was 7% for the HT patients, 4% for the CABG patients, and 16% for the CMP patients, and 1-year survival rates for those discharged were 94%, 91%, and 65%, respectively. Long-term survivors of CMP and CABG are functionally improved but still require medical therapy for CHF. Survivors of HT do not have CHF but suffer the consequences of immunosuppression.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of muscle origin and phenotype on satellite cell muscle-specific gene expression

Dynamic cardiomyoplasty has been used clinically to augment the ventricular function of a failing heart. Fifteen clinical dynamic cardiomyoplasties have been performed at Allegheny General Hospital since 1985. Left ventricular ejection fraction improved in long-term survivors from a preoperative value of 0.23 +/- 0.02 to 0.32 +/- 0.05 with postoperative cardiomyostimulation (p < 0.05). There was an average reduction of 2 +/- 0.3 New York Heart Association classes (3.6 +/- 0.2 before operation versus 1.6 +/- 0.4 after operation; p < 0.001). Postoperative mortality was 27% (4/15), and early mortality (within 6 months after operation) was 20% (3/15). Significant preoperative differences between survivors and nonsurvivors were found in right ventricular ejection fraction (0.53 +/- 0.03 versus 0.30 +/- 0.07; p < 0.05), pulmonary artery mean pressure (19 +/- 2 versus 34 +/- 6 mm Hg; p < 0.05), pulmonary artery diastolic pressure (12 +/- 1 versus 25 +/- 5 mm Hg; p < 0.05), and pulmonary vascular resistance (1.4 +/- 2 versus 2.5 +/- 0.7 Wood units; p < 0.05). Dynamic cardiomyoplasty can be done with low operative mortality in patients with isolated left ventricular failure, but mortality is high in those with biventricular failure or pulmonary hypertension. Improvement in functional class and ventricular function can be expected in long-term survivors. Application of these findings to patient selection will improve the risk/benefit ratio for dynamic cardiomyoplasty.

Right latissimus dorsi cardiomyoplasty for left ventricular failure

One hundred thirty consecutive patients who underwent mitral valve replacement (MVR) or MVR with coronary artery bypass grafting (CABG) using cold crystalloid cardioplegic solution were analyzed to determine operative mortality and risk factors. Twenty-eight patients had mitral stenosis (MS), 37 had mitral regurgitation (MR), 37 had mixed MS and MR, 23 had MR with coronary artery disease (CAD), and 5 had MS with CAD. Preoperative pulmonary artery pressure, pulmonary capillary wedge pressure, and cardiac index were not different among groups, but patients with MR and CAD had a significantly higher left ventricular end-diastolic pressure (LVEDP) and a significantly lower ejection fraction than other groups. Mortality was 7.1% for patients with MS, 5.4% for MR, 8.1% for mixed MS and MR, 0 for MS with CAD, and 21.7% for MR and CAD. Overall mortality was 9.2%. Eleven patients had emergency operations for cardiogenic shock with a mortality of 45%. Nineteen additional patients in New York Heart Association (NYHA) Functional Class IV had MVR or MVR plus CABG with a mortality of 26%. Sixteen patients required intraaortic balloon pump assistance, and 9 survived. Four patients with MR and CAD required the left ventricular assist device, and 3 survived. Excluding patients who had emergency operations, overall mortality was 5.8%. Excluding patients who had emergency operations and patients in NYHA Functional Class IV, overall mortality was 2%. Factors associated with death were cardiogenic shock, NYHA Class IV, LVEDP greater than 15 mm Hg (16% mortality), and age greater than 60 years (15% mortality).