A prospective randomized trial of Duraflo II heparin-coated circuits in cardiac reoperations.

BACKGROUND: Heparin-coated circuits in cardiopulmonary bypass have been shown to decrease the systemic inflammatory responses associated with cardiopulmonary bypass. Previous clinical studies on low-risk patients who had coronary artery bypass grafting (CABG) and received full-dose systemic heparin did not have clearly improved clinical outcomes. We hypothesized that the beneficial effects of heparin-coated circuits might be seen in patients who had cardiac reoperations. METHODS: Three hundred fifty patients who had reoperation with CABG only (58%), or with valve operations (42%) were randomly assigned to receive either a heparin-coated (Duraflo II; study group) or uncoated (control group) circuit. Clinical outcomes were compared and the variables were analyzed using the following three groups: entire populations of study group and control group, subgroup of patients who had CABG reoperation only, and a subgroup who had valve reoperation or combined valve and CABG reoperation. RESULTS: Preoperative variables were the same in both groups. No difference in clinical outcomes could be demonstrated except that the percentage of patients with major bleeding episodes was significantly lower in the study group (1.2% versus 5.4%, p = 0.035). In the subgroup analysis of patients who had valve reoperations, lower blood transfusion requirements in the intensive care unit (p = 0.013) were found in the study group. When the subgroup of patients who had CABG reoperations was analyzed separately, there was a trend toward less reoperation for bleeding in the study group (0% versus 4.0%, p = 0.058). CONCLUSIONS: We conclude that the use of heparin-coated circuits was safe and imparted protection from reoperations for bleeding and major bleeding episodes. Material-independent blood activation (eg, blood-air interface and cardiotomy suction) blunted the total effect of the heparin-coated surface.

Secular trends in nosocomial bloodstream infections in a 55-bed cardiothoracic intensive care unit.

BACKGROUND: Although bloodstream infections (BSIs) occur more frequently in intensive care unit patients than in ward patients, most studies of nosocomial BSIs in critically ill patients have not distinguished between intensive care unit populations beyond surgical, medical, and pediatric patients. METHODS: The primary objective of this study was to characterize the secular trends in rates of nosocomial BSIs for all pathogens among patients admitted to a busy cardiothoracic intensive care unit in a single tertiary care institution between January 1986 and December 1995. Patients with nosocomial BSIs were identified through continual prospective surveillance. RESULTS: A total of 40,207 patients were admitted to the cardiothoracic intensive care unit during the 10-year study period, and 804 episodes of nosocomial BSIs among 681 patients were identified. The mean crude BSI infection rate was 6.0 per 1,000 patient-care days and increased linearly during the study period (range, 4.4 to 8.1 per 1000 patient-care days), and approached statistical significance (p value = 0.07). The most common organisms causing BSIs were Staphylococcus aureus (12%), coagulase-negative staphylococci (11%), Candida albicans (11%), Pseudomonas aeruginosa (10%), and Enterococci (9%). The leading sources of nosocomial BSIs were primary BSIs (33%), intravascular devices (27%), lower respiratory tract infections (17%), and surgical wound infections (12%). The etiologic fraction or the proportion of deaths in cardiothoracic intensive care unit patients with BSIs was 15-fold higher than those patients without BSIs (37% versus 2.5%, p < 0.001). CONCLUSIONS: Rates of nosocomial BSIs among patients in our cardiothoracic intensive care unit have increased linearly during the past decade and patients with nosocomial BSIs have an increased risk of in hospital mortality.

Biocompatibility of heparin-coated extracorporeal bypass circuits: a randomized, masked clinical trial.

Cardiopulmonary bypass circuits cause morbidity during cardiac operations. Plasma proteins and cellular components are stimulated by contact with the cardiopulmonary bypass circuit and can cause bleeding and postperfusion syndrome. This is especially true in patients undergoing reoperative cardiac procedures, which carries a higher risk of postoperative bleeding and prolonged ventilation compared with primary cardiac surgical procedures. Recently, cardiopulmonary bypass circuit surfaces have been coated with antithrombotic agents to improve their biocompatibility. This study evaluated the effect of a heparin-coated cardiopulmonary bypass system (Duraflo II, Baxter Bentley Healthcare Systems, Irvine, Calif.) on thrombin formation, platelet stimulation, and leukocyte activation in patients undergoing reoperative coronary artery bypass grafting or valve operation. Fifty patients were selected and randomly assigned to a standard noncoated control system (n = 26) or the Duraflo heparin-coated system (n = 24). Similar heparin doses were used in both groups (3 mg/kg). The heparin-coated group used a completely heparin-coated bypass circuit including the cardiotomy reservoir; arterial filters were heparin-coated in both groups. Samples were obtained before cardiopulmonary bypass, 30 minutes into cardiopulmonary bypass, 5 minutes after crossclamp removal, and 5 minutes after protamine administration. Thrombin formation (thrombin-antithrombin III by enzyme-linked immunosorbent assays) and platelet activation (beta-thromboglobulin by enzyme-linked immunosorbent assays; P-selectin expression by flow cytometry) were assayed. Leukocyte activation was determined by quantitative and qualitative analysis of arterial filters by scanning electron microscopy in six patients from each group. In both circuits, thrombin values increased markedly 30 minutes into cardiopulmonary bypass compared with baseline values (p < 0.001) (heparin-coated, 7 +/- 5 to 96 +/- 115 ng/ml; noncoated, 10 +/- 9 to 115 +/- 125 ng/ml). Platelet activation as measured by beta-thromboglobulin (heparin-coated, 104 +/- 100 to 284 +/- 166 IU/ml; noncoated, 81 +/- 74 to 288 +/- 277 IU/ml) and P-selectin expression (heparin-coated, 1.5% +/- 1.5% to 6.4% +/- 6.1%; noncoated, 1.4% +/- 1.1% to 6.2% +/- 4.3%) also significantly increased 30 minutes into cardiopulmonary bypass compared with baseline values (p < 0.001). Platelet activation and thrombin generation did not differ between the two circuits at any time. Granulocyte activation and platelet deposition did not differ between the two circuits when arterial filters were evaluated. Both groups had similar heparin and protamine administration, blood transfusions, postoperative alveolar-arterial oxygen gradient, time to extubation, length of intensive care unit stay, and overall morbidity and mortality. Clinical outcome and blood loss did not differ between the groups. We conclude that heparin-coated cardiopulmonary bypass circuits did not improve biochemical or clinical markers of biocompatibility in a reoperative patient population.

Extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock.

BACKGROUND: Extracorporeal membrane oxygenation circuits have recently been introduced for extracorporeal life support (ECLS) in adult patients in cardiogenic shock and have been shown to provide excellent oxygenation and hemodynamic support. Heparin coating of the extracorporeal circuit provides a more biocompatible surface, which has been shown to minimize early surface-induced complement activation and platelet dysfunction and hence may improve patient survival. This report reviews our experience with extracorporeal membrane oxygenation to treat postcardiotomy cardiogenic shock using minimal to no systemic heparinization in 23 patients. METHODS: During the 22-month period September 1992 through July 1994, 23 patients in cardiogenic shock were placed on venoarterial ECLS using a heparin-bonded circuit. These patients' charts were retrospectively reviewed. A logistic regression analysis of the variables collected was performed to identify clear-cut predictors of ability to be weaned from ECLS. RESULTS: Average patient age was 47.3 +/- 16.4 years (range, 5 to 72 years). There were 17 male patients. Average time on ECLS was 58.4 +/- 35.1 hours (range, 0.5 to 144 hours). Statistical analysis revealed that patients unable to be weaned from ECLS were more likely to have a critically dilated left ventricle on echocardiography and were female. Ten patients (43.5%) died while on ECLS. Four patients were transferred to an implantable left ventricular assist device, and 3 underwent successful transplantation. The 9 other patients were successfully weaned from ECLS, and 4 were discharged home from the hospital. Overall, 7 patients (30.4%) who were placed on ECLS were successfully discharged home. CONCLUSIONS: Extracorporeal life support using an extracorporeal membrane oxygenation system provides excellent cardiac support with similar hospital survival rates as centrifugal mechanical support. Extracorporeal life support has complications unique to itself, but with time, these are likely to be overcome. Women and patients with persistent left ventricular dilatation are less likely to be weaned.

Have PTCA failures requiring emergent bypass operation changed?

From 1980 through 1990, 9,145 patients had balloon angioplasty with failure of the procedure requiring emergent surgical revascularization within 24 hours occurring in 253 patients (2.8%). Patients were divided into two cohorts based on the date of the percutaneous transluminal coronary angioplasty (PTCA): 1980 to 1985 (n = 109) and 1986 to 1990 (n = 144). The incidence of PTCA failure was 3.8% during 1980 to 1985 (109/2,903) and decreased to 2.3% (144/6,242) for 1986 to 1990. Comparison of pre-PTCA patient characteristics between the two periods showed that only a history of a previous PTCA and class III or class IV symptoms were more common in the recent years (p < or = 0.05). In-hospital mortality after emergency operation was 4.6% (5/109) during 1980 to 1985 and 7.6% (11/144) from 1985 to 1990 (p = not significant). This trend toward increased mortality appeared to be related to an increased number of patients who underwent operation in a state of severe hemodynamic compromise in the more recent period. The in-hospital mortality rate for patients in shock or undergoing cardiopulmonary resuscitation was 28.3% (13/46) compared with 1.4% (3/207) for patients with less severe hemodynamic derangement (p < 0.001). Use of the intraaortic balloon pump preoperatively increased from 12.8% to 32.6% (p < 0.01). Late survival was 92% at 2 and 87% at 5 postoperative years. Although the incidence of PTCA failure necessitating emergent surgical intervention has decreased over time, there has been a trend toward an increased in-hospital mortality rate for those patients that does not appear to be related to more severe pre-PTCA characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary isolated coronary artery bypass in left ventricular dysfunction: survival and predictors of survival.

Coronary angiograms of 462 patients with ejection fractions below 51% who underwent primary isolated coronary artery bypass at the Cleveland Clinic from 1981 to 1985 were available for review. They were divided into two groups: group 1 (n = 166) with severe ventricular dysfunction (ejection fraction less than 30%) and group 2 (n = 296) with moderate ventricular dysfunction (ejection fraction 31 to 50%) at a median follow-up of 5.8 years/patient. The actuarial survival was 64.3% in group 1 and 80.6% in group 2 (P = 0.0001). By multivariate analysis, congestive heart failure (P = 0.0001) was the single most important factor affecting survival for both groups. In addition, in group 1 the preoperative use of inotropes (P = 0.03) and in group 2 the presence of peripheral vascular disease (P = 0.001) affected long term survival.

Surgical treatment of isolated left anterior descending coronary stenosis. Comparison of left internal mammary artery and venous autograft at 18 to 20 years of follow-up.

To assess the long-term results of the surgical treatment of isolated left anterior descending coronary artery stenosis and compare surgical strategies for graft selection, we reviewed 100 consecutive patients receiving left internal mammary artery-to-left anterior descending artery grafts and 100 consecutive patients who received a saphenous vein autograft to the left anterior descending artery. All patients underwent operation from 1971 through 1973. The internal mammary artery and saphenous vein graft groups were equivalent with regard to preoperative clinical and angiographic variables, except that patients receiving left internal mammary artery grafts had a higher prevalence of noncritical disease (less than 50% stenosis) in the circumflex and right coronary arteries than did the saphenous vein graft group. Mean follow-up for the internal mammary artery and saphenous vein graft groups was 18.7 years and 20.7 years, respectively. The 18-year outcome was superior for the internal mammary artery group. Cox regression analysis confirmed that patients with left internal mammary artery grafts had superior survival, intervention-free survival, and event-free survival (all p < 0.01). The presence of noncritical disease in other vessels adversely affected intervention-free survival and event-free survival for both groups (all p < 0.03) and decreased survival for the saphenous vein graft group (p = 0.01) but not for the internal mammary artery group (p = 0.24). We conclude that in long-term follow-up of surgically treated isolated left anterior descending artery stenosis (1) the left internal mammary artery consistently yields better overall and intervention-free survival than does the saphenous vein graft, (2) outcome is influenced by the presence of noncritical disease in other vessels at the initial operation, and (3) deployment of the left internal mammary artery in the treatment of isolated left anterior descending artery stenosis yielded 18 years of intervention-free survival of 60.5% and provides a standard for comparison with other forms of therapeutic intervention.

Perioperative risk of bilateral internal mammary artery grafting: analysis of 500 cases from 1971 to 1984.

The records of the first 500 patients (420 men, 80 women, mean age 55 years, range 24 to 78) undergoing bilateral internal mammary artery (IMA) grafting were reviewed to determine in-hospital morbidity and mortality. Sixty patients (12%) had had previous cardiac operations and 130 (26%) previous saphenous vein removal. From two to seven total grafts (mean 3.2) were performed, including 595 IMA grafts to the anterior descending or diagonal artery, 355 to the circumflex, and 105 to the right coronary system. To assess changing risks, the first 125 patients (group A, 1971 to 1982) were compared with the next 375 (group B, 1982 to 1984). Major complications in groups A and B included stroke, four (3.2%) vs ine (2.4%); wound complications requiring reoperation, three (2.4%) vs five (1.3%); prolonged (greater than 48 hr) respiratory care, seven (5.6%) vs 19 (5.1%); and death, two (1.6%) vs five (1.3%) (no p value less than .05). Complications significantly less frequent in group B were new Q waves in nine (7.2%) vs 10 (2.7%) in group A (p = .02) and reoperation for bleeding in 17 (13.6%) vs 16 (4.3%) in group A (p = .0003). Logistic regression analysis showed that major complications did not correlate with gender, diabetes, number of grafts, or preoperative left ventricular function but were associated with increasing age (p = .0001) and previous cardiac surgery (p = .009) and were decreased by the use of cardioplegia (p = .002). The excellent long-term patency of IMA grafts, combined with low and decreasing perioperative risk, supports the continued use of bilateral IMA grafting.

Early results of emergency surgery after coronary angioplasty.

During the period of our study 81 patients undergoing elective coronary artery angioplasty at our institution required emergency revascularization surgery within the ensuing 24 hr. The mean age of the 59 men and 22 women was 57 years (32 to 74 years). The principal indications for the emergency surgery were acute occlusion (n = 36), dissection (n = 28), unstable angina (n = 10), ventricular arrhythmias (n = 4), and unsuccessful balloon dilatation (n = 3). There were two early deaths and in 35 patients the presence of three criteria for myocardial infarction was noted postoperatively. Including these patients, 52 patients surviving their hospital course suffered 75 major complications. Emergency surgery after failed percutaneous transluminal coronary angioplasty can be performed with low mortality, but it carries a high incidence of major postoperative complications.

Results of mitral valve reconstruction.

To evaluate the early results of mitral valve reconstruction for mitral insufficiency, 117 consecutive cases were analyzed. Sixty-four (57.7%) of the patients were men, and the mean age was 60 +/- 13 years (range 18 to 85). Eighty-nine (76%) of the patients were in NYHA functional class III or IV preoperatively. The cause of the mitral disease was degenerative in 94 (80%) and rheumatic in 13 (11%) patients. Isolated mitral valve repair was performed in 56 patients (47.9%); the remainder underwent associated procedures that included myocardial revascularization in 38 (32.5%). Ninety-nine (85%) underwent a ring annuloplasty but in only seven (6%) was this the only repair technique. Resection of the posterior leaflet was performed in 41 (35%). There were five operative deaths (4.3%); one (1.8%) occurred after isolated repair and four (6.5%) after repair with associated procedures. All deaths occurred in patients greater than 65 years of age who were in NYHA functional class III or IV. Mean follow-up was 13.5 months (range 1 to 62). Two year actuarial survival was 90.6%. Three patients required reoperation (incidence of 2.5% per patient-year). Two patients sustained embolic events (incidence of 1.6% per patient-year). There were no anticoagulant-related complications. After surgery, 100 survivors (96.2%) were in NYHA functional class I or II.

Young adults with coronary atherosclerosis: 10 year results of surgical myocardial revascularization.

This study reviews data on 107 patients, aged 35 years or younger, who underwent surgical coronary revascularization from 1971 to 1975. Early clinical events included one operative death and five nonfatal perioperative myocardial infarctions. Late follow-up (mean interval after operation 115 months) demonstrated actuarial survival rates of 94% at 5 years and 85% at 10 years. Fifteen late deaths, 23 nonfatal myocardial infarctions, 13 reoperations and return of severe angina in 10 patients were considered late clinical events. Actuarial survival free of early or late clinical events was 77% at 5 years and 53% at 10 postoperative years. Testing of clinical, angiographic and operative variables for influence on survival and event-free survival showed that survival was decreased by multivessel disease and impaired left ventricular function; event-free survival was decreased by a family history of coronary disease and cigarette smoking. Both survival and event-free survival were decreased by diabetes and elevated serum cholesterol. Postoperative cardiac catheterization (64 patients, mean postoperative interval 47 months) demonstrated that mammary artery graft patency (25 of 27, 93%) exceeded vein graft patency (49 of 88, 56%, p less than 0.01). The atherogenic diatheses of young adults may compromise the operative result, whereas use of internal mammary artery grafts may enhance the palliation of bypass surgery.

Extravascular lung water values in patients undergoing coronary artery bypass surgery.

Using a commercially produced lung water computer, we measured extravascular thermal volume (ETVL) to study changes in extravascular lung water (EVLW) caused by coronary artery bypass surgery. The normal baseline ETVL before anesthesia was 5.47 +/- 1.67 (SD) ml/kg. ETVL was not significantly changed 2 h after surgery but was significantly lower (P less than 0.05) 24 h later in 9 patients. There was no relationship between P(A-a)O2/FIO2 ratios and values of ETV1.